Science.gov

Sample records for acoustic thermography acat

  1. Air Coupled Acoustic Thermography (acat) Inspection Technique

    NASA Astrophysics Data System (ADS)

    Zalameda, J. N.; Winfree, W. P.; Yost, W. T.

    2008-02-01

    The scope of this effort is to determine the viability of a new heating technique using a noncontact acoustic excitation source. Because of low coupling between air and the structure, a synchronous detection method is employed. Any reduction in the out of plane stiffness improves the acoustic coupling efficiency and as a result, defective areas have an increase in temperature relative to the surrounding area. Hence a new measurement system, based on air-coupled acoustic energy and synchronous detection is presented. An analytical model of a clamped circular plate is given, experimentally tested, and verified. Repeatability confirms the technique with a measurement uncertainty of +/-6.2 percent. The range of frequencies used was 800-2,000 Hertz. Acoustic excitation and consequent thermal detection of flaws in a helicopter blade is examined and results indicate that air coupled acoustic excitation enables the detection of core damage in sandwich honeycomb structures.

  2. Air Coupled Acoustic Thermography (ACAT) Inspection Technique

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph; Winfree, William P.; Yost, William T.

    2007-01-01

    The scope of this effort is to determine the viability of a new heating technique using a noncontact acoustic excitation source. Because of low coupling between air and the structure, a synchronous detection method is employed. Any reduction in the out of plane stiffness improves the acoustic coupling efficiency and as a result, defective areas have an increase in temperature relative to the surrounding area. Hence a new measurement system, based on air-coupled acoustic energy and synchronous detection is presented. An analytical model of a clamped circular plate is given, experimentally tested, and verified. Repeatability confirms the technique with a measurement uncertainty of plus or minus 6.2 percent. The range of frequencies used was 800-2,000 Hertz. Acoustic excitation and consequent thermal detection of flaws in a helicopter blade is examined and results indicate that air coupled acoustic excitation enables the detection of core damage in sandwich honeycomb structures.

  3. Application of Air Coupled Acoustic Thermography (ACAT) for Inspection of Honeycomb Sandwich Structures

    NASA Technical Reports Server (NTRS)

    Winfree, William P.; Zalameda, Joseph N.; Pergantis, Charles; Flanagan, David; Deschepper, Daniel

    2009-01-01

    The application of a noncontact air coupled acoustic heating technique is investigated for the inspection of advanced honeycomb composite structures. A weakness in the out of plane stiffness of the structure, caused by a delamination or core damage, allows for the coupling of acoustic energy and thus this area will have a higher temperature than the surrounding area. Air coupled acoustic thermography (ACAT) measurements were made on composite sandwich structures with damage and were compared to conventional flash thermography. A vibrating plate model is presented to predict the optimal acoustic source frequency. Improvements to the measurement technique are also discussed.

  4. Air-coupled acoustic thermography for in-situ evaluation

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N. (Inventor); Winfree, William P. (Inventor); Yost, William T. (Inventor)

    2010-01-01

    Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and/or repeatability, sound and/or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

  5. Thermography.

    ERIC Educational Resources Information Center

    Cage, Bob N.

    1984-01-01

    Thermography, a diagnostic tool that combines photography and infrared sensing, permits direct measurement of apparent surface temperatures. Building energy losses can be detected and correction measures planned. Criteria for the use of thermography are provided. (MLF)

  6. Characterization of acoustic streaming and heating using synchronized infrared thermography and particle image velocimetry.

    PubMed

    Layman, Christopher N; Sou, In Mei; Bartak, Rico; Ray, Chittaranjan; Allen, John S

    2011-09-01

    Real-time measurements of acoustic streaming velocities and surface temperature fields using synchronized particle image velocimetry and infrared thermography are reported. Measurements were conducted using a 20 kHz Langevin type acoustic horn mounted vertically in a model sonochemical reactor of either degassed water or a glycerin-water mixture. These dissipative phenomena are found to be sensitive to small variations in the medium viscosity, and a correlation between the heat flux and vorticity was determined for unsteady convective heat transfer.

  7. A synchronized particle image velocimetry and infrared thermography technique applied to an acoustic streaming flow

    PubMed Central

    Sou, In Mei; Layman, Christopher N.; Ray, Chittaranjan

    2013-01-01

    Subsurface coherent structures and surface temperatures are investigated using simultaneous measurements of particle image velocimetry (PIV) and infrared (IR) thermography. Results for coherent structures from acoustic streaming and associated heating transfer in a rectangular tank with an acoustic horn mounted horizontally at the sidewall are presented. An observed vortex pair develops and propagates in the direction along the centerline of the horn. From the PIV velocity field data, distinct kinematic regions are found with the Lagrangian coherent structure (LCS) method. The implications of this analysis with respect to heat transfer and related sonochemical applications are discussed. PMID:24347810

  8. A synchronized particle image velocimetry and infrared thermography technique applied to an acoustic streaming flow.

    PubMed

    Sou, In Mei; Allen, John S; Layman, Christopher N; Ray, Chittaranjan

    2011-11-01

    Subsurface coherent structures and surface temperatures are investigated using simultaneous measurements of particle image velocimetry (PIV) and infrared (IR) thermography. Results for coherent structures from acoustic streaming and associated heating transfer in a rectangular tank with an acoustic horn mounted horizontally at the sidewall are presented. An observed vortex pair develops and propagates in the direction along the centerline of the horn. From the PIV velocity field data, distinct kinematic regions are found with the Lagrangian coherent structure (LCS) method. The implications of this analysis with respect to heat transfer and related sonochemical applications are discussed. PMID:24347810

  9. Combining Passive Thermography and Acoustic Emission for Large Area Fatigue Damage Growth Assessment of a Composite Structure

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Horne, Michael R.; Madaras, Eric I.; Burke, Eric R.

    2016-01-01

    Passive thermography and acoustic emission data were obtained for improved real time damage detection during fatigue loading. A strong positive correlation was demonstrated between acoustic energy event location and thermal heating, especially if the structure under load was nearing ultimate failure. An image processing routine was developed to map the acoustic emission data onto the thermal imagery. This required removing optical barrel distortion and angular rotation from the thermal data. The acoustic emission data were then mapped onto thermal data, revealing the cluster of acoustic emission event locations around the thermal signatures of interest. By combining both techniques, progression of damage growth is confirmed and areas of failure are identified. This technology provides improved real time inspections of advanced composite structures during fatigue testing.Keywords: Thermal nondestructive evaluation, fatigue damage detection, aerospace composite inspection, acoustic emission, passive thermography

  10. Determination of the dynamics of temperature variation in a model object by acoustic thermography

    NASA Astrophysics Data System (ADS)

    Anosov, A. A.; Belyaev, R. V.; Vilkov, V. A.; Kazanskiĭ, A. S.; Mansfel'D, A. D.; Sharakshané, A. S.

    2008-07-01

    An experiment on monitoring the dynamics of internal temperature variation in a model object by the acoustic thermography method is carried out. The measurements were performed in a cell filled with an aqueous solution of glycerol, into which a plasticine object was placed. Thermal acoustic radiation of the object was measured in the course of its heating and cooling. Two bars of acoustic thermometers positioned on two sides of the object were used for this purpose. The results of measurements allowed the reconstruction of the dynamics of the varying two-dimensional distribution of in-depth temperature. The position of the heated region, its temperature, and its characteristic size are estimated. In addition, an estimate is obtained for the absorption coefficient.

  11. Identification of ACAT1- and ACAT2-specific inhibitors using a novel, cell-based fluorescence assay: individual ACAT uniqueness.

    PubMed

    Lada, Aaron T; Davis, Matthew; Kent, Carol; Chapman, James; Tomoda, Hiroshi; Omura, Satoshi; Rudel, Lawrence L

    2004-02-01

    Acyl CoA:cholesterol acyltransferase 1 (ACAT1) and ACAT2 are enzymes responsible for the formation of cholesteryl esters in tissues. While both ACAT1 and ACAT2 are present in the liver and intestine, the cells containing either enzyme within these tissues are distinct, suggesting that ACAT1 and ACAT2 have separate functions. In this study, NBD-cholesterol was used to screen for specific inhibitors of ACAT1 and ACAT2. Incubation of AC29 cells, which do not contain ACAT activity, with NBD-cholesterol showed weak fluorescence when the compound was localized in the membrane. When AC29 cells stably transfected with either ACAT1 or ACAT2 were incubated with NBD-cholesterol, the fluorescent signal localized to the nonpolar core of cytoplasmic lipid droplets was strongly fluorescent and was correlated with two independent measures of ACAT activity. Several compounds were found to have greater inhibitory activity toward ACAT1 than ACAT2, and one compound was identified that specifically inhibits ACAT2. The demonstration of selective inhibition of ACAT1 and ACAT2 provides evidence for uniqueness in structure and function of these two enzymes. To the extent that ACAT2 is confined to hepatocytes and enterocytes, the only two cell types that secrete lipoproteins, selective inhibition of ACAT2 may prove to be most beneficial in the reduction of plasma lipoprotein cholesterol concentrations. PMID:14617738

  12. Combining passive thermography and acoustic emission for large area fatigue damage growth assessment of a composite structure

    NASA Astrophysics Data System (ADS)

    Zalameda, Joseph N.; Horne, Michael R.; Madaras, Eric I.; Burke, Eric R.

    2016-05-01

    Passive thermography and acoustic emission data were obtained for improved real time damage detection during fatigue loading. A strong positive correlation was demonstrated between acoustic energy event location and thermal heating, especially if the structure under load was nearing ultimate failure. An image processing routine was developed to map the acoustic emission data onto the thermal imagery. This required removing optical barrel distortion and angular rotation from the thermal data. The acoustic emission data were then mapped onto thermal data, revealing the cluster of acoustic emission event locations around the thermal signatures of interest. By combining both techniques, progression of damage growth is confirmed and areas of failure are identified. This technology provides improved real time inspections of advanced composite structures during fatigue testing.

  13. Automatic Collision Avoidance Technology (ACAT)

    NASA Technical Reports Server (NTRS)

    Swihart, Donald E.; Skoog, Mark A.

    2007-01-01

    This document represents two views of the Automatic Collision Avoidance Technology (ACAT). One viewgraph presentation reviews the development and system design of Automatic Collision Avoidance Technology (ACAT). Two types of ACAT exist: Automatic Ground Collision Avoidance (AGCAS) and Automatic Air Collision Avoidance (AACAS). The AGCAS Uses Digital Terrain Elevation Data (DTED) for mapping functions, and uses Navigation data to place aircraft on map. It then scans DTED in front of and around aircraft and uses future aircraft trajectory (5g) to provide automatic flyup maneuver when required. The AACAS uses data link to determine position and closing rate. It contains several canned maneuvers to avoid collision. Automatic maneuvers can occur at last instant and both aircraft maneuver when using data link. The system can use sensor in place of data link. The second viewgraph presentation reviews the development of a flight test and an evaluation of the test. A review of the operation and comparison of the AGCAS and a pilot's performance are given. The same review is given for the AACAS is given.

  14. Buying Thermography

    NASA Astrophysics Data System (ADS)

    Madding, Robert P.

    1981-01-01

    The cost of thermographic information obtained by contracting for a service is compared to that of buying equipment and doing the work in-house. A breakeven analysis method is used to find the number of days per year an instrument must be used to justify buying it. Life-cycle costing techniques are used to find the equivalent annual cost of various classes of thermographic instruments. Results indicate that a full-time person earning 20,000 annually must use a 30,000 instrument at least 73 days per year if thermography can otherwise be contracted for $675 per day. By devoting a person to thermography part-time, the number of inspection days for this case can be reduced to about 28. Further in-house advantage can be gained by considering investment tax credits, salvage value and, to some extent, accelerated depreciation. Techniques for finding the breakeven number of inspection days for other costs are developed. A nomogram is included for rapid comparisons.

  15. Synthetic conversion of ACAT inhibitor to acetylcholinesterase inhibitor.

    PubMed

    Obata, R; Sunazuka, T; Otoguro, K; Tomoda, H; Harigaya, Y; Omura, S

    2000-06-19

    Natural product acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor pyripyropene A was synthetically converted to acetylcholinesterase (AChE) inhibitor via heterolitic cleavage of the 2-pyrone ring, followed by gamma-acylation/cyclization with several aroyl chlorides. The 4-pyridyl analogue selectively showed AChE inhibitory activity (IC50 7.9 microM) and no ACAT inhibitory activity IC50 = >1000 microM. PMID:10890154

  16. Isoform-specific inhibitors of ACATs: recent advances and promising developments.

    PubMed

    Ohshiro, Taichi; Tomoda, Hiroshi

    2011-12-01

    Acyl-CoA:cholesterol acyltransferase (ACAT) is a promising therapeutic target for cardiovascular diseases. Although a number of synthetic ACAT inhibitors have been developed, they have failed to show efficacy in clinical trials. Now, the presence of two ACAT isoforms with distinct functions, ACAT1 and ACAT2, has been discovered. Thus, the selectivity of ACAT inhibitors toward the two isoforms is important for their development as novel anti-atherosclerotic agents. The selectivity study indicated that fungal pyripyropene A (PPPA) is only an ACAT2-specific inhibitor. Furthermore, PPPA proved orally active in atherogenic mouse models, indicating it possessed cholesterol-lowering and atheroprotective activities. Certain PPPA derivatives, semi-synthetically prepared, possessed more potent and selective in vitro activity than PPPA against ACAT2. This review covers these studies and describes the future prospects of ACAT2-specific inhibitors. PMID:22098352

  17. Cholesterol esterification by ACAT2 is essential for efficient intestinal cholesterol absorption: evidence from thoracic lymph duct cannulation[S

    PubMed Central

    Nguyen, Tam M.; Sawyer, Janet K.; Kelley, Kathryn L.; Davis, Matthew A.; Rudel, Lawrence L.

    2012-01-01

    The hypothesis tested in this study was that cholesterol esterification by ACAT2 would increase cholesterol absorption efficiency by providing cholesteryl ester (CE) for incorporation into chylomicrons. The assumption was that absorption would be proportional to Acat2 gene dosage. Male ACAT2+/+, ACAT2+/−, and ACAT2−/− mice were fed a diet containing 20% of energy as palm oil with 0.2% (w/w) cholesterol. Cholesterol absorption efficiency was measured by fecal dual-isotope and thoracic lymph duct cannulation (TLDC) methods using [3H]sitosterol and [14C]cholesterol tracers. Excellent agreement among individual mice was found for cholesterol absorption measured by both techniques. Cholesterol absorption efficiency in ACAT2−/− mice was 16% compared with 46–47% in ACAT2+/+ and ACAT2+/− mice. Chylomicrons from ACAT2+/+ and ACAT2+/− mice carried ∼80% of total sterol mass as CE, whereas ACAT2−/− chylomicrons carried >90% of sterol mass in the unesterified form. The total percentage of chylomicron mass as CE was reduced from 12% in the presence of ACAT2 to ∼1% in ACAT2−/− mice. Altogether, the data demonstrate that ACAT2 increases cholesterol absorption efficiency by providing CE for chylomicron transport, but one copy of the Acat2 gene, providing ∼50% of ACAT2 mRNA and enzyme activity, was as effective as two copies in promoting cholesterol absorption. PMID:22045928

  18. Mass-production of human ACAT-1 and ACAT-2 to screen isoform-specific inhibitor: a different substrate specificity and inhibitory regulation.

    PubMed

    Cho, Kyung-Hyun; An, Sojin; Lee, Woo-Song; Paik, Young-Ki; Kim, Young-Kook; Jeong, Tae-Sook

    2003-10-01

    Recently, acyl-CoA:cholesterol acyltransferase was found to be present as two isoforms, ACAT-1 and ACAT-2, in mammalian tissues with different metabolic functions and tissue-specific locations. In this study, the isoforms were mass-produced individually from insect cells to establish a more sensitive and reliable screening method for specific inhibitors against each isoform. The expressed hACAT-1 and hACAT-2 appeared as a 50 kDa- and a 46 kDa-band on SDS-PAGE, respectively, from Hi5 cells and they preferred to exist in oligomeric form, from dimer to tetramer, during the purification process. They also exhibited an approximate 3.4 to 3.7-fold increase in activities when compared to rat liver microsomal fractions at the same protein concentration. Known ACAT inhibitors, pyripyropene A, oleic acid anilide, and diethyl pyrocarbonate, were tested to evaluate the inhibitory specificity and sensitivity of the expressed enzymes. Interestingly, pyripyropene A inhibited only the hACAT-2 fraction with IC(50)=0.64 microM but not the hACAT-1 fraction; whereas the fatty acid anilide did not show a significant difference in inhibitory activity with either hACAT-1 or hACAT-2. Furthermore, cholesterol was more rapidly utilized by hACAT-1, but hACAT-2 esterified other cholic acid derivatives more efficiently. These results suggest that the specificity of each substrate and inhibitor was highly different, depending on each isoform from the viewpoint of the regulatory site and the substrate binding site location. PMID:13679053

  19. Nondestructive testing with thermography

    NASA Astrophysics Data System (ADS)

    Ibarra-Castanedo, Clemente; Tarpani, José Ricardo; Maldague, Xavier P. V.

    2013-11-01

    Thermography is a nondestructive testing (NDT) technique based on the principle that two dissimilar materials, i.e., possessing different thermo-physical properties, would produce two distinctive thermal signatures that can be revealed by an infrared sensor, such as a thermal camera. The fields of NDT applications are expanding from classical building or electronic components monitoring to more recent ones such as inspection of artworks or composite materials. Furthermore, thermography can be conveniently used as a didactic tool for physics education in universities given that it provides the possibility of visualizing fundamental principles, such as thermal physics and mechanics among others.

  20. Clinical applications of computerized thermography

    NASA Technical Reports Server (NTRS)

    Anbar, Michael

    1988-01-01

    Computerized or digital, thermography is a rapidly growing diagnostic imaging modality. It has superseded contact thermography and analog imaging thermography which do not allow effective quantization. Medical applications of digital thermography can be classified in two groups: static and dynamic imaging. They can also be classified into macro thermography (resolution greater than 1 mm) and micro thermography (resolution less than 100 microns). Both modalities allow a thermal resolution of 0.1 C. The diagnostic power of images produced by any of these modalities can be augmented by the use of digital image enhancement and image recognition procedures. Computerized thermography has been applied in neurology, cardiovascular and plastic surgery, rehabilitation and sports medicine, psychiatry, dermatology and ophthalmology. Examples of these applications are shown and their scope and limitations are discussed.

  1. Evaluation of infrared thermography body temperature and collar-mounted accelerometer and acoustic technology for predicting time of ovulation of cows in a pasture-based system.

    PubMed

    Talukder, S; Thomson, P C; Kerrisk, K L; Clark, C E F; Celi, P

    2015-03-01

    This study was conducted to test the hypothesis that the specificity of infrared thermography (IRT) in detecting cows about to ovulate could be improved using different body parts that are less likely to be contaminated by fecal matter. In addition, the combined activity and rumination data captured by accelerometers were evaluated to provide a more accurate indication of ovulation than the activity and rumination data alone. Thermal images of 30 cows were captured for different body areas (eye, ear, muzzle, and vulva) twice daily after AM and PM milking sessions during the entire experimental period. Milk progesterone data and insemination records were used to determine the date of ovulation. Cows were fitted with SCR heat and rumination long-distance tags (SCR HR LD) for 1 month. Activity- and rumination-based estrus alerts were initially identified using default threshold values set by the manufacturer; however, a range of thresholds was also created and tested for both activity and rumination to determine the potential for higher levels of accuracy of ovulation detection. Visual assessment of mounting indicators resulted in 75% sensitivity (Se), 100% specificity (Sp), and 100% positive predictive value (PPV). Overall, IRT showed poor performance for detecting cows about to ovulate. Vulval temperature resulted in the greatest (80%) Sp but the poorest (21%) Se compared with the IRT temperatures of other body areas. The SCR HR LD tags default threshold value resulted in 78% Se, 57% Sp, and 70% PPV. Lowering the activity threshold from the default value improved the sensitivity but created a large number of false positives, which resulted in a decrease in specificity. Lowering the activity threshold to 20 resulted in a detection performance of 80% Se, 94% Sp, and 67% PPV, whereas the rumination levels achieved 35% Se, 69% Sp, and 14% PPV. The area under the curve for the activity level, rumination level, and the combined measures of activity and rumination levels

  2. Thermography in Neurologic Practice

    PubMed Central

    Neves, Eduardo Borba; Vilaça-Alves, José; Rosa, Claudio; Reis, Victor Machado

    2015-01-01

    One kind of medical images that has been developed in the last decades is thermal images. These images are assessed by infrared cameras and have shown an exponential development in recent years. In this sense, the aim of this study was to describe possibilities of thermography usage in the neurologic practice. It was performed a systematic review in Web of Knowledge (Thompson Reuters), set in all databases which used two combination of keywords as “topic”: “thermography” and “neurology”; and “thermography” and “neurologic”. The chronological period was defined from 2000 to 2014 (the least 15 years). Among the studies included in this review, only seven were with experimental design. It is few to bring thermography as a daily tool in clinical practice. However, these studies have suggested good results. The studies of review and an analyzed patent showed that the authors consider the thermography as a diagnostic tool and they recommend its usage. It can be concluded that thermography is already used as a diagnostic and monitoring tool of patients with neuropathies, particularly in complex regional pain syndrome, and stroke. And yet, this tool has great potential for future research about its application in diagnosis of other diseases of neurological origin. PMID:26191090

  3. [The instrument for thermography].

    PubMed

    Hamaguchi, Shinsuke

    2014-07-01

    Thermography is an imaging method using the instrument to detect infrared rays emitted from the body surface, and to plot them as a distribution diagram of the temperature information. Therefore, a thermographic instrument can be assumed to measure the skin temperature of the diseased region. Such an instrument is a useful device for noninvasive and objective assessment of various diseases. Examination using a thermographic instrument can assess the autonomic dysfunction by measuring the skin blood flow involved with the sympathetic innervation. Thermography is useful in assisting the determination of the therapeutic effect. However, autonomic dysfunction should be confirmed correctly with the assessment of thermatome that shows abnormal thermal distribution in the region of the disease. Thermography should make noticeable the difference between the body temperature of abnormal and normal sites, and show the alteration of temperature. Monitoring using thermography is useful to determine the effect of sympathetic nerve block. If a thermographic instrument is used, it is important that examiners should understand the function of the instrument, as well as its advantages and disadvantages. PMID:25098130

  4. Effect of nitrogen and temperature on the transcription of an ACAT gene in Isochrysis galbana.

    PubMed

    Huang, Yijiang; Zheng, Minggang; Wan, Wenwen; Sun, Zhongtao

    2014-11-01

    Thiolases are functionally divided into two groups: 3-ketoacyl-CoA thiolase and acetoacetyl-CoA thiolase (ACAT). Acetoacetyl-CoA thiolase plays a key role in the mevalonate pathway. In this study, a novel gene, IgACAT, which encodes ACAT was cloned from Isochrysis galbana and characterized. The cDNA of IgACAT was 1551 bp in length, consisting of an open reading frame of 1173 bp, a 5' untranslated region of 69 bp and a 3' untranslated region of 309 bp. The deduced amino acid sequence of IgACAT was 390 amino acid residues in length with a predicted molecular weight of 53.59 kDa and an isoelectric point of pH 9.04. The triterpenes content and the expression of IgACAT under nitrogen and temperature stress were analyzed. When I. galbana was treated with excessive nitrogen and at 35 °C, respectively, both the triterpenes content and the abundance of IgACAT gene transcript increased. Our findings will facilitate the regulation of gene expression and genetic modification of the triterpenes synthesis pathway of I. galbana.

  5. Effects of moisture in infrared thermography of resin matrix composites

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Kantsios, A. G.; Mcerlean, E. A.; Babcock, R. A.; Buckingham, R. D.

    1978-01-01

    Several multiply graphite polyimide composite specimens were examined by real-time infrared thermography in order to study the effects of moisture on their thermograms. Heat was injected from one side and IR emission detected on the opposite side using AGA Thermovision System-680. No differences between the thermograms of dry and water containing specimens were detected for defect-free specimens. However, the presence of trapped water in defective specimens modified the thermographic contrast significantly. It is concluded that: (1) IR thermography can be used to detect moisture in defective composites, and (2) because of the possibility of moisture camouflaging defects, IR thermography for subsurface defect detection should be supplemented by other techniques - such as acoustical imaging and X-radiography.

  6. Tissue-specific knockouts of ACAT2 reveal that intestinal depletion is sufficient to prevent diet-induced cholesterol accumulation in the liver and blood[S

    PubMed Central

    Zhang, Jun; Kelley, Kathryn L.; Marshall, Stephanie M.; Davis, Matthew A.; Wilson, Martha D.; Sawyer, Janet K.; Farese, Robert V.; Brown, J. Mark; Rudel, Lawrence L.

    2012-01-01

    Acyl-CoA:cholesterol acyltransferase 2 (ACAT2) generates cholesterol esters (CE) for packaging into newly synthesized lipoproteins and thus is a major determinant of blood cholesterol levels. ACAT2 is expressed exclusively in the small intestine and liver, but the relative contributions of ACAT2 expression in these tissues to systemic cholesterol metabolism is unknown. We investigated whether CE derived from the intestine or liver would differentially affect hepatic and plasma cholesterol homeostasis. We generated liver-specific (ACAT2L−/L−) and intestine-specific (ACAT2SI−/SI−) ACAT2 knockout mice and studied dietary cholesterol-induced hepatic lipid accumulation and hypercholesterolemia. ACAT2SI−/SI− mice, in contrast to ACAT2L−/L− mice, had blunted cholesterol absorption. However, specific deletion of ACAT2 in the intestine generated essentially a phenocopy of the conditional knockout of ACAT2 in the liver, with reduced levels of plasma very low-density lipoprotein and hepatic CE, yet hepatic-free cholesterol does not build up after high cholesterol intake. ACAT2L−/L− and ACAT2SI−/SI− mice were equally protected from diet-induced hepatic CE accumulation and hypercholesterolemia. These results suggest that inhibition of intestinal or hepatic ACAT2 improves atherogenic hyperlipidemia and limits hepatic CE accumulation in mice and that depletion of intestinal ACAT2 is sufficient for most of the beneficial effects on cholesterol metabolism. Inhibitors of ACAT2 targeting either tissue likely would be beneficial for atheroprotection. PMID:22460046

  7. Intestine-specific MTP and global ACAT2 deficiency lowers acute cholesterol absorption with chylomicrons and HDLs

    PubMed Central

    Boutjdir, Mohamed; Rudel, Lawrence L.; Hussain, M. Mahmood

    2014-01-01

    Intestinal cholesterol absorption involves the chylomicron and HDL pathways and is dependent on microsomal triglyceride transfer protein (MTP) and ABCA1, respectively. Chylomicrons transport free and esterified cholesterol, whereas HDLs transport free cholesterol. ACAT2 esterifies cholesterol for secretion with chylomicrons. We hypothesized that free cholesterol accumulated during ACAT2 deficiency may be secreted with HDLs when chylomicron assembly is blocked. To test this, we studied cholesterol absorption in mice deficient in intestinal MTP, global ACAT2, and both intestinal MTP and global ACAT2. Intestinal MTP ablation significantly increased intestinal triglyceride and cholesterol levels and reduced their transport with chylomicrons. In contrast, global ACAT2 deficiency had no effect on triglyceride absorption but significantly reduced cholesterol absorption with chylomicrons and increased cellular free cholesterol. Their combined deficiency reduced cholesterol secretion with both chylomicrons and HDLs. Thus, contrary to our hypothesis, free cholesterol accumulated in the absence of MTP and ACAT2 is unavailable for secretion with HDLs. Global ACAT2 deficiency causes mild hypertriglyceridemia and reduces hepatosteatosis in mice fed high cholesterol diets by increasing hepatic lipoprotein production by unknown mechanisms. We show that this phenotype is preserved in the absence of intestinal MTP in global ACAT2-deficient mice fed a Western diet. Further, we observed increases in hepatic MTP activity in these mice. Thus, ACAT2 deficiency might increase MTP expression to avoid hepatosteatosis in cholesterol-fed animals. Therefore, ACAT2 inhibition might avert hepatosteatosis associated with high cholesterol diets by increasing hepatic MTP expression and lipoprotein production. PMID:25030663

  8. Material Evaluation by Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Holland, Stephen D.; Reusser, Ricky S.

    2016-07-01

    Infrared thermography uses the temperature-imaging capability of modern thermal cameras to characterize materials and detect flaws. An energy source—whether a pulse of light from a laser or flash lamp, an induction coil, or some other source—induces heat flow in a material, and the resulting temperature patterns are imaged with the thermal camera. In flash thermography, the most widely used form of quantitative thermography, a pulse of light is used as the energy source, and then the surface cooldown is imaged with the thermal camera. Calculations based on an elementary theory of 1D heat conduction can determine thickness (or, equivalently, thermal diffusivity), and nonuniformity in the cooldown will identify defects. This article reviews the methods, approaches, and models of thermography. It focuses on illustrating and identifying the materials, thicknesses, and flaw conditions under which thermography is an effective material characterization technique.

  9. Aerial thermography for energy conservation

    NASA Technical Reports Server (NTRS)

    Jack, J. R.

    1978-01-01

    Thermal infrared scanning from an aircraft is a convenient and commercially available means for determining relative rates of energy loss from building roofs. The need to conserve energy as fuel costs makes the mass survey capability of aerial thermography an attractive adjunct to community energy awareness programs. Background information on principles of aerial thermography is presented. Thermal infrared scanning systems, flight and environmental requirements for data acquisition, preparation of thermographs for display, major users and suppliers of thermography, and suggested specifications for obtaining aerial scanning services were reviewed.

  10. Hepatic ACAT2 Knock Down Increases ABCA1 and Modifies HDL Metabolism in Mice

    PubMed Central

    Degirolamo, Chiara; Gomaraschi, Monica; Graham, Mark; Ossoli, Alice; Larsson, Lilian; Calabresi, Laura; Gustafsson, Jan-Åke; Steffensen, Knut R.; Eriksson, Mats; Parini, Paolo

    2014-01-01

    Objectives ACAT2 is the exclusive cholesterol-esterifying enzyme in hepatocytes and enterocytes. Hepatic ABCA1 transfers unesterified cholesterol (UC) to apoAI, thus generating HDL. By changing the hepatic UC pool available for ABCA1, ACAT2 may affect HDL metabolism. The aim of this study was to reveal whether hepatic ACAT2 influences HDL metabolism. Design WT and LXRα/β double knockout (DOKO) mice were fed a western-type diet for 8 weeks. Animals were i.p. injected with an antisense oligonucleotide targeted to hepatic ACAT2 (ASO6), or with an ASO control. Injections started 4 weeks after, or concomitantly with, the beginning of the diet. Results ASO6 reduced liver cholesteryl esters, while not inducing UC accumulation. ASO6 increased hepatic ABCA1 protein independently of the diet conditions. ASO6 affected HDL lipids (increased UC) only in DOKO, while it increased apoE-containing HDL in both genotypes. In WT mice ASO6 led to the appearance of large HDL enriched in apoAI and apoE. Conclusions The use of ASO6 revealed a new pathway by which the liver may contribute to HDL metabolism in mice. ACAT2 seems to be a hepatic player affecting the cholesterol fluxes fated to VLDL or to HDL, the latter via up-regulation of ABCA1. PMID:24695360

  11. ACAT1 deletion in murine macrophages associated with cytotoxicity and decreased expression of collagen type 3A1

    SciTech Connect

    Rodriguez, Annabelle . E-mail: arodrig5@jhmi.edu; Ashen, M. Dominique; Chen, Edward S.

    2005-05-27

    In contrast to some published studies of murine macrophages, we previously showed that ACAT inhibitors appeared to be anti-atherogenic in primary human macrophages in that they decreased foam cell formation without inducing cytotoxicity. Herein, we examined foam cell formation and cytotoxicity in murine ACAT1 knockout (KO) macrophages in an attempt to resolve the discrepancies. Elicited peritoneal macrophages from normal C57BL6 and ACAT1 KO mice were incubated with DMEM containing acetylated LDL (acLDL, 100 {mu}g protein/ml) for 48 h. Cells became cholesterol enriched and there were no differences in the total cholesterol mass. Esterified cholesterol mass was lower in ACAT1 KO foam cells compared to normal macrophages (p < 0.04). Cytotoxicity, as measured by the cellular release of [{sup 14}C]adenine from macrophages, was approximately 2-fold greater in ACAT1 KO macrophages as compared to normal macrophages (p < 0.0001), and this was independent of cholesterol enrichment. cDNA microarray analysis showed that ACAT1 KO macrophages expressed substantially less collagen type 3A1 (26-fold), which was confirmed by RT-PCR. Total collagen content was also significantly reduced (57%) in lung homogenates isolated from ACAT1 KO mice (p < 0.02). Thus, ACAT1 KO macrophages show biochemical changes consistent with increased cytotoxicity and also a novel association with decreased expression of collagen type 3A1.

  12. Synthesis and structure-activity relationship of pyripyropene A derivatives as potent and selective acyl-CoA:cholesterol acyltransferase 2 (ACAT2) inhibitors: part 1.

    PubMed

    Ohtawa, Masaki; Yamazaki, Hiroyuki; Ohte, Satoshi; Matsuda, Daisuke; Ohshiro, Taichi; Rudel, Lawrence L; Omura, Satoshi; Tomoda, Hiroshi; Nagamitsu, Tohru

    2013-03-01

    In an effort to develop potent and selective inhibitors toward ACAT2, structure-activity relationship studies were carried out using derivatives based on pyripyropene A (PPPA, 1). We have successfully developed novel PPPA derivatives with a 7-O-substituted benzoyl substituent that significantly exhibit more potent ACAT2 inhibitory activity and higher ACAT2 isozyme selectivity than 1. PMID:23369538

  13. Design and synthesis of simple, yet potent and selective non-ring-A pyripyropene A-based inhibitors of acyl-coenzyme A: cholesterol acyltransferase 2 (ACAT2).

    PubMed

    Zhan, Yang; Zhang, Xiao-Wei; Xiong, Ying; Li, Bo-Liang; Nan, Fa-Jun

    2016-01-14

    A series of pyripyropene A-based compounds were designed and synthesized by opening the upper section of the A-ring, which significantly simplifies the structure and synthesis from commercially available starting materials. Representative compound (-)-3 exhibited potent activity against ACAT2 and greater selectivity for ACAT2 than for ACAT1. PMID:26584338

  14. PREFACE: 16th International workshop on Advanced Computing and Analysis Techniques in physics research (ACAT2014)

    NASA Astrophysics Data System (ADS)

    Fiala, L.; Lokajicek, M.; Tumova, N.

    2015-05-01

    This volume of the IOP Conference Series is dedicated to scientific contributions presented at the 16th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2014), this year the motto was ''bridging disciplines''. The conference took place on September 1-5, 2014, at the Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic. The 16th edition of ACAT explored the boundaries of computing system architectures, data analysis algorithmics, automatic calculations, and theoretical calculation technologies. It provided a forum for confronting and exchanging ideas among these fields, where new approaches in computing technologies for scientific research were explored and promoted. This year's edition of the workshop brought together over 140 participants from all over the world. The workshop's 16 invited speakers presented key topics on advanced computing and analysis techniques in physics. During the workshop, 60 talks and 40 posters were presented in three tracks: Computing Technology for Physics Research, Data Analysis - Algorithms and Tools, and Computations in Theoretical Physics: Techniques and Methods. The round table enabled discussions on expanding software, knowledge sharing and scientific collaboration in the respective areas. ACAT 2014 was generously sponsored by Western Digital, Brookhaven National Laboratory, Hewlett Packard, DataDirect Networks, M Computers, Bright Computing, Huawei and PDV-Systemhaus. Special appreciations go to the track liaisons Lorenzo Moneta, Axel Naumann and Grigory Rubtsov for their work on the scientific program and the publication preparation. ACAT's IACC would also like to express its gratitude to all referees for their work on making sure the contributions are published in the proceedings. Our thanks extend to the conference liaisons Andrei Kataev and Jerome Lauret who worked with the local contacts and made this conference possible as well as to the program

  15. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  16. Thermography pattern analysis and separation

    NASA Astrophysics Data System (ADS)

    Gao, Bin; Bai, Libing; Woo, W. L.; Tian, Guiyun

    2014-06-01

    Analysis of thermography spatial-transient patterns has considerable potential to enable automatic identification and quantification of defects in non-destructive testing and evaluation. This Letter proposes a non-negative pattern separation model for eddy current pulsed thermography to automatically extract important spatial and time patterns according to the transient thermal sequences without any pre-training or prior knowledge. In particular, the method is scale-invariant, such that large differences in surface emissivity, hot spots, and cool areas with dynamic range of thermal contrast can be extracted. Finally, an artificial slot in a steel sample with shining, black strip on the surface is tested to validate the proposed method.

  17. Acyl-CoA:cholesterol acyltransferases (ACATs/SOATs): Enzymes with multiple sterols as substrates and as activators.

    PubMed

    Rogers, Maximillian A; Liu, Jay; Song, Bao-Liang; Li, Bo-Liang; Chang, Catherine C Y; Chang, Ta-Yuan

    2015-07-01

    Cholesterol is essential to the growth and viability of cells. The metabolites of cholesterol include: steroids, oxysterols, and bile acids, all of which play important physiological functions. Cholesterol and its metabolites have been implicated in the pathogenesis of multiple human diseases, including: atherosclerosis, cancer, neurodegenerative diseases, and diabetes. Thus, understanding how cells maintain the homeostasis of cholesterol and its metabolites is an important area of study. Acyl-coenzyme A:cholesterol acyltransferases (ACATs, also abbreviated as SOATs) converts cholesterol to cholesteryl esters and play key roles in the regulation of cellular cholesterol homeostasis. ACATs are most unusual enzymes because (i) they metabolize diverse substrates including both sterols and certain steroids; (ii) they contain two different binding sites for steroidal molecules. In mammals, there are two ACAT genes that encode two different enzymes, ACAT1 and ACAT2. Both are allosteric enzymes that can be activated by a variety of sterols. In addition to cholesterol, other sterols that possess the 3-beta OH at C-3, including PREG, oxysterols (such as 24(S)-hydroxycholesterol and 27-hydroxycholesterol, etc.), and various plant sterols, could all be ACAT substrates. All sterols that possess the iso-octyl side chain including cholesterol, oxysterols, various plant sterols could all be activators of ACAT. PREG can only be an ACAT substrate because it lacks the iso-octyl side chain required to be an ACAT activator. The unnatural cholesterol analogs epi-cholesterol (with 3-alpha OH in steroid ring B) and ent-cholesterol (the mirror image of cholesterol) contain the iso-octyl side chain but do not have the 3-beta OH at C-3. Thus, they can only serve as activators and cannot serve as substrates. Thus, within the ACAT holoenzyme, there are site(s) that bind sterol as substrate and site(s) that bind sterol as activator; these sites are distinct from each other. These features form

  18. Acyl-CoA:cholesterol acyltransferases (ACATs/SOATs): enzymes with multiple sterols as substrates and as activators

    PubMed Central

    Rogers, Maximillian A.; Liu, Jay; Song, Bao-Liang; Li, Bo-Liang; Chang, Catherine C.Y.; Chang, Ta-Yuan

    2016-01-01

    Cholesterol is essential to the growth and viability of cells. The metabolites of cholesterol include: steroids, oxysterols, and bile acids, all of which play important physiological functions. Cholesterol and its metabolites have been implicated in the pathogenesis of multiple human diseases, including: atherosclerosis, cancer, neurodegenerative diseases, and diabetes. Thus, understanding how cells maintain the homeostasis of cholesterol and its metabolites is an important area of study. Acyl-coenzyme A:cholesterol acyltransferases (ACATs, also abbreviated as SOATs) converts cholesterol to cholesteryl esters and play key roles in the regulation of cellular cholesterol homeostasis. ACATs are most unusual enzymes because (i) they metabolize diverse substrates including both sterols and certain steroids; (ii) they contain two different binding sites for steroidal molecules. In mammals, there are two ACAT genes that encode two different enzymes, ACAT1 and ACAT2. Both are allosteric enzymes that can be activated by a variety of sterols. In addition to cholesterol, other sterols that possess the 3-beta OH at C-3, including PREG, oxysterols (such as 24(S)-hydroxycholesterol and 27-hydroxycholesterol, etc.), and various plant sterols, could all be ACAT substrates. All sterols that possess the iso-octyl side chain including cholesterol, oxysterols, various plant sterols could all be activators of ACAT. PREG can only be an ACAT substrate because it lacks the isooctyl side chain required to be an ACAT activator. The unnatural cholesterol analogs epi-cholesterol (with 3-alpha OH in steroid ring B) and ent-cholesterol (the mirror image of cholesterol) contain the iso-octyl side chain but do not have the 3-beta OH at C-3. Thus, they can only serve as activators and cannot serve as substrates. Thus, within the ACAT holoenzyme, there are site(s) that bind sterol as substrate and site(s) that bind sterol as activator; these sites are distinct from each other. These features form

  19. Measurement limits in flash thermography

    NASA Astrophysics Data System (ADS)

    Shepard, Steven M.; Lhota, James R.; Ahmed, Tasdiq

    2009-05-01

    Although active thermography has traditionally been regarded as a qualitative NDT method, its potential for quantitative measurement of thermophysical properties including wall thickness, flaw size and depth, thermal diffusivity or effusivity has been the subject of numerous investigations. Enabled by improvements in IR camera technology and fast, abundant and inexpensive computing power for advanced signal processing, measurement results have been reported using a variety of excitation and signal processing schemes. Results are often presented as a correlation between thermography data and nominal properties or independent measurements by another "validated" method. However, given the diffusion mechanism that underlies thermography, and the quantization and sampling conditions implicit in using an IR camera as a temperature sensor, there are definite limits to what can be achieved in a thermography measurement. While many benefits can be achieved with improved instrumentation, efficient energy insertion or optimized signal processing, ultimately, the limits imposed by diffusion and instrumentation take precedence, and cannot be circumvented. In this paper, the effects of camera frame rate and sensitivity on measurement of the thickness of a slab are examined, using basic 1-dimensional diffusion approximations.

  20. Veterinary applications of infrared thermography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abnormal temperature is a major indicator of disease; infrared thermography (IRT) can assess changes in surface temperature quickly and remotely. This technology can be applied to myriad diseases in veterinary medicine, ranging across host species and disease etiologies. It can also be used to deter...

  1. Estrogen Decreases Atherosclerosis In Part By Reducing Hepatic Acyl-CoA:Cholesterol Acyltransferase 2 (ACAT2) In Monkeys

    PubMed Central

    Kavanagh, Kylie; Davis, Matthew A.; Zhang, Li; Wilson, Martha D.; Register, Thomas C.; Adams, Michael R.; Rudel, Lawrence L.; Wagner, Janice D.

    2009-01-01

    Objective Estrogens decrease atherosclerosis progression, mediated in part through changes in plasma lipids and lipoproteins. This study aimed to determine estrogen-induced changes in hepatic cholesterol metabolism, plasma lipoproteins, and the relationship of these changes to atherosclerosis extent. Methods and Results Ovariectomized monkeys (n=34) consumed atherogenic diets for 30 months which contained either no hormones (control, n=17) or conjugated equine estrogens (CEE, n=17) at a human dose equivalent of 0.625 mg/d. Hepatic cholesterol content, low-density lipoprotein (LDL) receptor expression, cholesterol 7α-hydroxylase and acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity and expression levels were determined. CEE treatment resulted in lower plasma concentrations of very-low- and intermediate density lipoprotein cholesterol (V+IDLC; p=0.01), smaller LDL particles (p=0.002) and 50% lower hepatic cholesterol content (total, free and esterified; p<0.05 for all). Total ACAT activity was significantly lower (p=0.01), explained primarily by reductions in the activity of ACAT2. Estrogen regulation of enzymatic activity was at the protein level as both ACAT1 and 2 protein, but not mRNA levels, were lower (p=0.02 and <0.0001, respectively). ACAT2 activity was significantly associated with hepatic total cholesterol, plasma V+IDLC cholesterol, and atherosclerosis. Conclusions Atheroprotective effects of estrogen therapy may be related to reduced hepatic secretion of ACAT2-derived cholesteryl esters in plasma lipoproteins. Condensed Abstract Estrogen inhibits atherogenesis. We demonstrate in ovariectorized monkeys that estrogen therapy led to lower hepatic and circulating lipoprotein cholesterol, and lower ACAT2 protein and associated activity levels as compared to controls. Hepatic ACAT2 activity was highly correlated with, and was an independent predictor of coronary artery atherosclerosis extent. PMID:19759374

  2. Relationship between bioavailability and hypocholesterolemic activity of YM17E, an inhibitor of ACAT, in cholesterol-fed rats.

    PubMed

    Uchida, T; Aoyama, K; Watanabe, T; Higuchi, S

    1998-03-01

    The relationship between bioavailability and the serum cholesterol-lowering effect of YM17E, an ACAT inhibitor was investigated. Serum cholesterol levels in cholesterol-fed rats decreased after both oral and intravenous administration of YM17E. Marked inhibition of cholesterol absorption was observed after oral administration, but not after intravenous administration. YM17E and its five active metabolites were primarily distributed in the liver after intravenous administration, but in small intestine and liver after oral administration. Hepatic ACAT activity in cholesterol-fed rats was inhibited by intravenous administration. Cholesteryl ester input into plasma by Triton WR-1339 treatment to the rats was inhibited by intravenous administration of YM17E. Plasma clearance of 125I-LDL in cholesterol-fed rats increased after YM17E treatment suggesting a decrease in LDL production. These results indicate that the hypocholesterolemic effect of intravenous YM17E was due to hepatic ACAT inhibition, not an inhibition of intestinal cholesterol absorption. The contribution of ACAT inhibition in small intestine and liver on the pharmacological effect could be explained by plasma inhibitor concentration after oral or intravenous administration of YM17E. From these results, it is concluded that the change in bioavailability of ACAT inhibitors change the mechanism of hypocholesterolemic effects, shifting the relative contributions of small intestinal and hepatic ACAT inhibition. PMID:9568741

  3. Summary of the ACAT Round Table Discussion: Open-source, knowledge sharing and scientific collaboration

    NASA Astrophysics Data System (ADS)

    Carminati, Federico; Perret-Gallix, Denis; Riemann, Tord

    2014-06-01

    Round table discussions are in the tradition of ACAT. This year's plenary round table discussion was devoted to questions related to the use of scientific software in High Energy Physics and beyond. The 90 minutes of discussion were lively, and quite a lot of diverse opinions were spelled out. Although the discussion was, in part, controversial, the participants agreed unanimously on several basic issues in software sharing: • The importance of having various licensing models in academic research; • The basic value of proper recognition and attribution of intellectual property, including scientific software; • The user respect for the conditions of use, including licence statements, as formulated by the author. The need of a similar discussion on the issues of data sharing was emphasized and it was recommended to cover this subject at the conference round table discussion of next ACAT. In this contribution, we summarise selected topics that were covered in the introductory talks and in the following discussion.

  4. PREFACE: 15th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT2013)

    NASA Astrophysics Data System (ADS)

    Wang, Jianxiong

    2014-06-01

    This volume of Journal of Physics: Conference Series is dedicated to scientific contributions presented at the 15th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2013) which took place on 16-21 May 2013 at the Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China. The workshop series brings together computer science researchers and practitioners, and researchers from particle physics and related fields to explore and confront the boundaries of computing and of automatic data analysis and theoretical calculation techniques. This year's edition of the workshop brought together over 120 participants from all over the world. 18 invited speakers presented key topics on the universe in computer, Computing in Earth Sciences, multivariate data analysis, automated computation in Quantum Field Theory as well as computing and data analysis challenges in many fields. Over 70 other talks and posters presented state-of-the-art developments in the areas of the workshop's three tracks: Computing Technologies, Data Analysis Algorithms and Tools, and Computational Techniques in Theoretical Physics. The round table discussions on open-source, knowledge sharing and scientific collaboration stimulate us to think over the issue in the respective areas. ACAT 2013 was generously sponsored by the Chinese Academy of Sciences (CAS), National Natural Science Foundation of China (NFSC), Brookhaven National Laboratory in the USA (BNL), Peking University (PKU), Theoretical Physics Cernter for Science facilities of CAS (TPCSF-CAS) and Sugon. We would like to thank all the participants for their scientific contributions and for the en- thusiastic participation in all its activities of the workshop. Further information on ACAT 2013 can be found at http://acat2013.ihep.ac.cn. Professor Jianxiong Wang Institute of High Energy Physics Chinese Academy of Science Details of committees and sponsors are available in the PDF

  5. ACAT inhibition reduces the progression of pre-existing, advanced atherosclerotic mouse lesions without plaque or systemic toxicity

    PubMed Central

    Rong, James X.; Blachford, Courtney; Feig, Jonathan E.; Bander, Ilda; Mayne, Jeffrey; Kusunoki, Jun; Miller, Christine; Davis, Matthew; Wilson, Martha; Dehn, Shirley; Thorp, Edward; Tabas, Ira; Taubman, Mark B.; Rudel, Lawrence L.; Fisher, Edward A.

    2013-01-01

    Objective Acyl-CoA:cholesterol acyltransferase (ACAT) converts cholesterol to cholesteryl esters in plaque foam cells. Complete deficiency of macrophage ACAT has been shown to increase atherosclerosis in hypercholesterolemic mice due to cytotoxicity from free cholesterol accumulation, while we previously showed that partial ACAT inhibition by Fujirebio compound F1394 decreased early atherosclerosis development. In this report, we tested F1394 effects on pre-established, advanced lesions of apoE-/- mice. Methods & Results ApoE-/- mice on Western diet for 14 weeks developed advanced plaques, and were either sacrificed (“Baseline”), or continued on Western diet without or with F1394 and sacrificed after 14 more weeks. F1394 was not associated with systemic toxicity. Compared to the baseline group, lesion size progressed in both groups; however, F1394 significantly retarded plaque progression, and reduced plaque macrophage, free and esterified cholesterol, and tissue factor contents compared to the untreated group. Apoptosis of plaque cells was not increased, consistent with the decrease in lesional free cholesterol, plaque necrosis was not increased, and efferocytosis (phagocytic clearance of apoptotic cells) was not impaired. The effects of F1394 were independent of changes in plasma cholesterol levels. Conclusions Partial ACAT inhibition by F1394 lowered plaque cholesterol content and had other antiatherogenic effects in advanced lesions in apoE-/- mice without overt systemic or plaque toxicity, suggesting the continued potential of ACAT inhibition for the clinical treatment of atherosclerosis in spite of recent trial data. PMID:23139293

  6. Assignment of the human cytosolic acetoacetyl-coenzyme a thiolase (ACAT2) gene to chromosome 6q25.3-q26

    SciTech Connect

    Masuno, Mitsuo; Imaizumi, Kiyoshi; Kuroki, Yoshikazu

    1996-08-15

    This report describes the localization of the human cytosolic acetoacetyl-coenzyme A thiolase (ACAT2) gene to human chromosome 6q25.3-q26 using fluorescence in situ hybridization. ACAT2 is involved in steroid biosynthesis; deficiency of this coenzyme results in a phenotype which includes severe mental retardation. 11 refs., 1 fig.

  7. Pyripyropenes, Novel ACAT inhibitors produced by Aspergillus fumigatus. III. Structure elucidation of pyripyropenes E to L.

    PubMed

    Tomoda, H; Tabata, N; Yang, D J; Takayanagi, H; Nishida, H; Omura, S; Kaneko, T

    1995-06-01

    Eight new pyripyropenes, E to L, were isolated from the culture broth of Aspergillus fumigatus FO-1289-2501 selected as a higher producer by NTG mutation. Structural elucidation indicated that all the pyripyropenes have the same pyridino-alpha-pyrone sesquiterpene core as pyripyropenes A to D. Among them, pyripyropene L showed the most potent inhibition against acyl-CoA: cholesterol acyltransferase (ACAT) activity with an IC50 value of 0.27 microM in rat liver microsomes. PMID:7622436

  8. Reliable aerial thermography for energy conservation

    NASA Technical Reports Server (NTRS)

    Jack, J. R.; Bowman, R. L.

    1981-01-01

    A method for energy conservation, the aerial thermography survey, is discussed. It locates sources of energy losses and wasteful energy management practices. An operational map is presented for clear sky conditions. The map outlines the key environmental conditions conductive to obtaining reliable aerial thermography. The map is developed from defined visual and heat loss discrimination criteria which are quantized based on flat roof heat transfer calculations.

  9. Origin of gene overlap: the case of TCP1 and ACAT2.

    PubMed Central

    Shintani, S; O'hUigin, C; Toyosawa, S; Michalová, V; Klein, J

    1999-01-01

    The human acetyl-CoA acetyltransferase 2 gene, ACAT2, codes for a thiolase, an enzyme involved in lipid metabolism. The human T-complex protein 1 gene, TCP1, encodes a molecular chaperone of the chaperonin family. The two genes overlap by their 3'-untranslated regions, their coding sequences being located on opposite DNA strands in a tail-to-tail orientation. To find out how the overlap might have arisen in evolution, the homologous genes of the zebrafish, the African toad, caiman, platypus, opossum, and wallaby were identified. In each species, standard or long polymerase chain reactions were used to determine whether the ACAT2 and TCP1 homologs are closely linked and, if so, whether they overlap. The results reveal that the overlap apparently arose during the transition from therapsid reptiles to mammals and has been retained for >200 million years. Part of the overlapping untranslated region shows remarkable sequence conservation. The overlap presumably arose during the chromosomal rearrangement that brought the two unrelated and previously separated genes together. One or both of the transposed genes found by chance signals that are necessary for the processing of their transcripts to be present on the noncoding strand of the partner gene. PMID:10353914

  10. In vitro metabolism of pyripyropene A and ACAT inhibitory activity of its metabolites.

    PubMed

    Matsuda, Daisuke; Ohshiro, Taichi; Ohtawa, Masaki; Yamazaki, Hiroyuki; Nagamitsu, Tohru; Tomoda, Hiroshi

    2015-01-01

    Pyripyropene A (PPPA, 1) of fungal origin, a selective inhibitor of acyl-CoA:cholesterol acyltransferase 2 (ACAT2), proved orally active in atherogenic mouse models. The in vitro metabolites of 1 in liver microsomes and plasma of human, rabbit, rat and mouse were analyzed by ultra fast liquid chromatography and liquid chromatography/tandem mass spectrometry. In the liver microsomes from all species, successive hydrolysis occurred at the 1-O-acetyl residue, then at the 11-O-acetyl residue of 1, while the 7-O-acetyl residue was resistant to hydrolysis. Furthermore, dehydrogenation of the newly generated 11-alcoholic hydroxyl residue occurred in human and mouse-liver microsomes, while oxidation of the pyridine ring occurred in human and rabbit liver microsomes. On the other hand, hydrolysis of the 7-O-acetyl residue proceeded only in the mouse plasma. These data indicated that the in vitro metabolic profiles of 1 have subtle differences among animal species. All of the PPPA metabolites observed in liver microsomes and plasma markedly decreased ACAT2 inhibitory activity. These findings will help us to synthesize new PPPA derivatives more effective in in vivo study than 1. PMID:25005817

  11. Novel N-terminal Cleavage of APP Precludes Aβ Generation in ACAT-Defective AC29 Cells

    PubMed Central

    Huttunen, Henri J.; Puglielli, Luigi; Ellis, Blake C.; Ingano, Laura A. MacKenzie

    2009-01-01

    A common pathogenic event that occurs in all forms of Alzheimer’s disease is the progressive accumulation of amyloid β-peptide (Aβ) in brain regions responsible for higher cognitive functions. Inhibition of acyl-coenzyme A: cholesterol acyltransferase (ACAT), which generates intracellular cholesteryl esters from free cholesterol and fatty acids, reduces the biogenesis of the Aβ from the amyloid precursor protein (APP). Here we have used AC29 cells, defective in ACAT activity, to show that ACAT activity steers APP either toward or away from a novel proteolytic pathway that replaces both α and the amyloidogenic β cleavages of APP. This alternative pathway involves a novel cleavage of APP holoprotein at Glu281, which correlates with reduced ACAT activity and Aβ generation in AC29 cells. This sterol-dependent cleavage of APP occurs in the endosomal compartment after internalization of cell surface APP. The resulting novel C-terminal fragment APP-C470 is destined to proteasomal degradation limiting the availability of APP for the Aβ generating system. The proportion of APP molecules that are directed to the novel cleavage pathway is regulated by the ratio of free cholesterol and cholesteryl esters in cells. These results suggest that subcellular cholesterol distribution may be an important regulator of the cellular fate of APP holoprotein and that there may exist several competing proteolytic systems responsible for APP processing within the endosomal compartment. PMID:18618086

  12. ACAT2 and human hepatic cholesterol metabolism: identification of important gender-related differences in normolipidemic, non-obese Chinese patients

    PubMed Central

    Parini, Paolo; Jiang, Zhao-Yan; Einarsson, Curt; Eggertsen, Gösta; Zhang, Sheng-Dao; Rudel, Lawrence L; Han, Tian-Quan; Eriksson, Mats

    2009-01-01

    Objective ACAT2 is a major cholesterol esterification enzyme specifically expressed in hepatocytes and may control the amount of hepatic free (unesterified) cholesterol available for secretion into bile or into HDL. This study aims to further elucidate physiologic roles of ACAT2 in human hepatic cholesterol metabolism. Methods and Results Liver biopsies from 40 normolipidemic, non-obese gallstone patients including some gallstone-free patients (female/male, 18/22) were collected and analyzed for microsomal ACAT2 activity, protein and mRNA expression. Plasma HDL-cholesterol (HDL-C) was significantly higher in females than in males, while triglycerides were significantly lower. ACAT2 activity in females was significantly lower than observed in males, regardless of the presence of gallstone disease. Moreover, the activity of ACAT2 correlated negatively with plasma levels of HDL-C (r=−0.57, P<0.05) and with Apo AI (r=−0.49, P<0.05). Conclusion This is the first description of a gender-related difference in hepatic ACAT2 activity in normolipidemic non-obese Chinese patients suggesting a possible role for ACAT2 in the regulation of cholesterol metabolism in humans. The negative correlation between ACAT2 activity and HDL-C or Apo AI may reflect this regulation. Since ACAT2 activity generally has been found to be pro-atherogenic in animal models, the observed sex-related difference may contribute to female protection from complications of coronary heart disease (CHD). PMID:19467657

  13. Thermography to Inspect Insulation of Large Cryogenic Tanks

    NASA Technical Reports Server (NTRS)

    Arens, Ellen; Youngquist, Robert

    2011-01-01

    Thermography has been used in the past to monitor active, large, cryogenic storage tanks. This approach proposes to use thermography to monitor new or refurbished tanks, prior to filling with cryogenic liquid, to look for insulation voids. Thermography may provide significant cost and schedule savings if voids can be detected early before a tank is returned to service.

  14. Fighting Testing ACAT/FRRP: Automatic Collision Avoidance Technology/Fighter Risk Reduction Project

    NASA Technical Reports Server (NTRS)

    Skoog, Mark A.

    2009-01-01

    This slide presentation reviews the work of the Flight testing Automatic Collision Avoidance Technology/Fighter Risk Reduction Project (ACAT/FRRP). The goal of this project is to develop common modular architecture for all aircraft, and to enable the transition of technology from research to production as soon as possible to begin to reduce the rate of mishaps. The automated Ground Collision Avoidance System (GCAS) system is designed to prevent collision with the ground, by avionics that project the future trajectory over digital terrain, and request an evasion maneuver at the last instance. The flight controls are capable of automatically performing a recovery. The collision avoidance is described in the presentation. Also included in the presentation is a description of the flight test.

  15. ACAT inhibition of alkamides identified in the fruits of Piper nigrum.

    PubMed

    Rho, Mun-Chual; Lee, Seung Woong; Park, Hye Ran; Choi, Jung-Ho; Kang, Ji Yun; Kim, Koanhoi; Lee, Hyun Sun; Kim, Young Kook

    2007-03-01

    In this study, via a bioactivity-guided fractionation of MeOH extracts of the fruits of Piper nigrum, alkamide (5) and five previously-identified alkamides were isolated. Their structures were elucidated via spectroscopic analysis ((1)H, (13)C NMR and ESI-MS), as follows: retrofractamide A (1), pipercide (2), piperchabamide D (3), pellitorin (4), dehydroretrofractamide C (5) and dehydropipernonaline (6). The IC(50) values determined for the compounds were 24.5 (1), 3.7 (2), 13.5 (3), 40.5 (4), 60 (5) and 90 microM (6), according to the results of an ACAT enzyme assay system using rat liver microsomes. These compounds all inhibited cholesterol esterification in HepG2 cells.

  16. 3D medical thermography device

    NASA Astrophysics Data System (ADS)

    Moghadam, Peyman

    2015-05-01

    In this paper, a novel handheld 3D medical thermography system is introduced. The proposed system consists of a thermal-infrared camera, a color camera and a depth camera rigidly attached in close proximity and mounted on an ergonomic handle. As a practitioner holding the device smoothly moves it around the human body parts, the proposed system generates and builds up a precise 3D thermogram model by incorporating information from each new measurement in real-time. The data is acquired in motion, thus it provides multiple points of view. When processed, these multiple points of view are adaptively combined by taking into account the reliability of each individual measurement which can vary due to a variety of factors such as angle of incidence, distance between the device and the subject and environmental sensor data or other factors influencing a confidence of the thermal-infrared data when captured. Finally, several case studies are presented to support the usability and performance of the proposed system.

  17. IR Thermography NDE of ISS Radiator Panels

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay; Winfree, William; Morton, Richard; Wilson, Walter; Reynolds, Gary

    2010-01-01

    The presentation covers an active and a passive infrared (IR) thermography for detection of delaminations in the radiator panels used for the International Space Station (ISS) program. The passive radiator IR data was taken by a NASA astronaut in an extravehicular activity (EVA) using a modified FLIR EVA hand-held camera. The IR data could be successfully analyzed to detect gross facesheet disbonds. The technique used the internal hot fluid tube as the heat source in analyzing the IR data. Some non-flight ISS radiators were inspected using an active technique of IR flash thermography to detect disbond of face sheet with honeycomb core, and debonds in facesheet overlap areas. The surface temperature and radiated heat emission from flight radiators is stable during acquisition of the IR video data. This data was analyzed to detect locations of unexpected surface temperature gradients. The flash thermography data was analyzed using derivative analysis and contrast evolutions. Results of the inspection are provided.

  18. Exit Presentation: Infrared Thermography on Graphite/Epoxy

    NASA Technical Reports Server (NTRS)

    Comeaux, Kayla

    2010-01-01

    This slide presentation reports on the internship project that was accomplished during the summer of 2010. The objectives of the project were to: (1) Simulate Flash Thermography on Graphite/Epoxy Flat Bottom hole Specimen and thin void specimens, (2) Obtain Flash Thermography data on Graphite/Epoxy flat bottom hole specimens, (3) Compare experimental results with simulation results, Compare Flat Bottom Hole Simulation with Thin Void Simulation to create a graph to determine size of IR Thermography detected defects

  19. Infrared thermography in the architectural field.

    PubMed

    Meola, Carosena

    2013-01-01

    Infrared thermography is becoming ever more popular in civil engineering/architecture mainly due to its noncontact character which includes two great advantages. On one side, it prevents the object, under inspection, from any alteration and this is worthwhile especially in the presence of precious works of art. On the other side, the personnel operate in a remote manner far away from any hazard and this complies well with safety at work regulations. What is more, it offers the possibility to quickly inspect large surfaces such as the entire facade of a building. This paper would be an overview of the use of infrared thermography in the architectural and civil engineering field. First, some basic testing procedures are described, and then some key examples are presented owing to both laboratory tests and applications in situ spanning from civil habitations to works of art and archaeological sites.

  20. Infrared Thermography in the Architectural Field

    PubMed Central

    2013-01-01

    Infrared thermography is becoming ever more popular in civil engineering/architecture mainly due to its noncontact character which includes two great advantages. On one side, it prevents the object, under inspection, from any alteration and this is worthwhile especially in the presence of precious works of art. On the other side, the personnel operate in a remote manner far away from any hazard and this complies well with safety at work regulations. What is more, it offers the possibility to quickly inspect large surfaces such as the entire facade of a building. This paper would be an overview of the use of infrared thermography in the architectural and civil engineering field. First, some basic testing procedures are described, and then some key examples are presented owing to both laboratory tests and applications in situ spanning from civil habitations to works of art and archaeological sites. PMID:24319358

  1. Liquid crystal thermography in boiling heat transfer

    SciTech Connect

    Klausner, J.F.; Mei, R.; Chen, W.C.

    1995-12-31

    The utilization of liquid crystal thermography to study heterogeneous boiling phenomena has gained popularity in recent years. In order not to disturb the nucleation process, which occurs in the microstructure of the heating surface, the crystals are applied to the backside of a thin heater. This work critically examines the ability of liquid crystal thermography to quantitatively capture the thermal field on the boiling surface. The thermal field identified experimentally through liquid crystal thermography is compared against that computed in the vicinity of a growing vapor bubble using a simulation which considers the simultaneous heat transfer between three phases: the solid heater, the liquid microlayer, and the growing vapor bubble. The temperature history beneath a growing vapor bubble elucidates the high frequency response required to capture the transient thermal fields commonly encountered in boiling experiments. Examination of the governing equations and numerical results reveal that due to the heater thermal inertia, the temperature variation on the bottom of the heater is significantly different than that on the boiling surface. In addition, the crystals themselves have a finite spatial resolution and frequency response which filter out much of the microscale phenomenon associated with boiling heat transfer. Analysis of existing pool and flow boiling liquid crystal thermographs indicate that the typical spacial resolution is on the order of 0.25 mm and the response time is on the order of 5 ms which are insufficient to resolve the fine spacial and temporal details of the heating surface thermal field. Thus the data obtained from liquid crystal thermography applied to boiling heat transfer must be cautiously interpreted.

  2. Method of thermography in diagnosing cardiovascular diseases

    NASA Astrophysics Data System (ADS)

    Lazyuk, D. G.; Sidorenko, I. V.; Krushevskaya, T. V.

    1996-05-01

    We investigated the possibility of using infrared thermography (IT) in diagnosing the commonest cardiovascular diseases: ischemic heart disease (IHD) and hypertensive disease (HD). We show that the IT method allows one to evaluate the condition of peripheral blood flow, but the results of examination depend greatly on the presence of accompanying diseases (osteochondrosis, varicosis). The IT method is not specific enough to evaluate the functional state of a myocardium.

  3. NDT of railway components using induction thermography

    NASA Astrophysics Data System (ADS)

    Netzelmann, U.; Walle, G.; Ehlen, A.; Lugin, S.; Finckbohner, M.; Bessert, S.

    2016-02-01

    Induction or eddy current thermography is used to detect surface cracks in ferritic steel. The technique is applied to detect surface cracks in rails from a moving test car. Cracks were detected at a train speed between 2 and 15 km/h. An automated demonstrator system for testing railway wheels after production is described. While the wheel is rotated, a robot guides the detection unit consisting of inductor and infrared camera over the surface.

  4. Quantitative Evaluation of Pulsed Thermography, Lock-in Thermography and Vibrothermography on Foreign Object Defect (FOD) in CFRP

    PubMed Central

    Liu, Bin; Zhang, Hai; Fernandes, Henrique; Maldague, Xavier

    2016-01-01

    In this article, optical excitation thermographic techniques, including pulsed thermography and lock-in thermography, were used to detect foreign object defect (FOD) and delamination in CFRP. Then, vibrothermography as an ultrasonic excitation technique was used to detect these defects for the comparative purposes. Different image processing methods, including cold image subtraction (CIS), principal component thermography (PCT), thermographic signal reconstruction (TSR) and Fourier transform (FT), were performed. Finally, a comparison of optical excitation thermography and vibrothermography was conducted, and a thermographic probability of detection was given. PMID:27213403

  5. Quantitative Evaluation of Pulsed Thermography, Lock-in Thermography and Vibrothermography on Foreign Object Defect (FOD) in CFRP.

    PubMed

    Liu, Bin; Zhang, Hai; Fernandes, Henrique; Maldague, Xavier

    2016-05-21

    In this article, optical excitation thermographic techniques, including pulsed thermography and lock-in thermography, were used to detect foreign object defect (FOD) and delamination in CFRP. Then, vibrothermography as an ultrasonic excitation technique was used to detect these defects for the comparative purposes. Different image processing methods, including cold image subtraction (CIS), principal component thermography (PCT), thermographic signal reconstruction (TSR) and Fourier transform (FT), were performed. Finally, a comparison of optical excitation thermography and vibrothermography was conducted, and a thermographic probability of detection was given.

  6. Synthesis and structure-activity relationship of pyripyropene A derivatives as potent and selective acyl-CoA:cholesterol acyltransferase 2 (ACAT2) inhibitors: part 3.

    PubMed

    Ohtawa, Masaki; Yamazaki, Hiroyuki; Ohte, Satoshi; Matsuda, Daisuke; Ohshiro, Taichi; Rudel, Lawrence L; Ōmura, Satoshi; Tomoda, Hiroshi; Nagamitsu, Tohru

    2013-07-01

    In an effort to develop potent and selective inhibitors toward ACAT2, structure-activity relationship studies were carried out using derivatives based on pyripyropene A (PPPA, 1). In particular, we investigated the possibility of introducing appropriate 1,11-O-benzylidene and 7-O-substituted benzoyl moieties into PPPA (1). The new o-substituted benzylidene derivatives showed higher selectivity for ACAT2 than PPPA (1). Among them, 1,11-O-o-methylbenzylidene-7-O-p-cyanobenzoyl PPPA derivative 7q and 1,11-O-o,o-dimethylbenzylidene-7-O-p-cyanobenzoyl PPPA derivative 7z proved to be potent ACAT2 inhibitors with unprecedented high isozyme selectivity. PMID:23711919

  7. Multiple mechanisms limit the accumulation of unesterified cholesterol in the small intestine of mice deficient in both ACAT2 and ABCA1.

    PubMed

    Turley, Stephen D; Valasek, Mark A; Repa, Joyce J; Dietschy, John M

    2010-11-01

    Cholesterol homeostasis in the enterocyte is regulated by the interplay of multiple genes that ultimately determines the net amount of cholesterol reaching the circulation from the small intestine. The effect of deleting these genes, particularly acyl CoA:cholesterol acyl transferase 2 (ACAT2), on cholesterol absorption and fecal sterol excretion is well documented. We also know that the intestinal mRNA level for adenosine triphosphate-binding cassette transporter A1 (ABCA1) increases in Acat2(-/-) mice. However, none of these studies has specifically addressed how ACAT2 deficiency impacts the relative proportions of esterified and unesterified cholesterol (UC) in the enterocyte and whether the concurrent loss of ABCA1 might result in a marked buildup of UC. Therefore, the present studies measured the expression of numerous genes and related metabolic parameters in the intestine and liver of ACAT2-deficient mice fed diets containing either added cholesterol or ezetimibe, a selective sterol absorption inhibitor. Cholesterol feeding raised the concentration of UC in the small intestine, and this was accompanied by a significant reduction in the relative mRNA level for Niemann-Pick C1-like 1 (NPC1L1) and an increase in the mRNA level for both ABCA1 and ABCG5/8. All these changes were reversed by ezetimibe. When mice deficient in both ACAT2 and ABCA1 were fed a high-cholesterol diet, the increase in intestinal UC levels was no greater than it was in mice lacking only ACAT2. This resulted from a combination of compensatory mechanisms including diminished NPC1L1-mediated cholesterol uptake, increased cholesterol efflux via ABCG5/8, and possibly rapid cell turnover.

  8. ACAT2 and ABCG5/G8 are both required for efficient cholesterol absorption in mice: evidence from thoracic lymph duct cannulation[S

    PubMed Central

    Nguyen, Tam M.; Sawyer, Janet K.; Kelley, Kathryn L.; Davis, Matthew A.; Kent, Carol R.; Rudel, Lawrence L.

    2012-01-01

    The metabolic fate of newly absorbed cholesterol and phytosterol is orchestrated through adenosine triphosphate-binding cassette transporter G5 and G8 heterodimer (G5G8), and acyl CoA:cholesterol acyltransferase 2 (ACAT2). We hypothesized that intestinal G5G8 limits sterol absorption by reducing substrate availability for ACAT2 esterification and have attempted to define the roles of these two factors using gene deletion studies in mice. Male ACAT2−/−, G5G8−/−, ACAT2−/−G5G8−/− (DKO), and wild-type (WT) control mice were fed a diet with 20% of energy as palm oil and 0.2% (w/w) cholesterol. Sterol absorption efficiency was directly measured by monitoring the appearance of [3H]sitosterol and [14C]cholesterol tracers in lymph after thoracic lymph duct cannulation. The average percentage (± SEM) absorption of [14C]cholesterol after 8 h of lymph collection was 40.55 ± 0.76%, 19.41 ± 1.52%, 32.13 ± 1.60%, and 21.27 ± 1.35% for WT, ACAT2−/−, G5G8−/−, and DKO mice, respectively. [3H]sitosterol absorption was <2% in WT and ACAT2−/− mice, whereas it was up to 6.8% in G5G8−/− and DKO mice. G5G8−/− mice also produced chylomicrons with ∼70% less cholesterol ester mass than WT mice. In contrast to expectations, the data demonstrated that the absence of G5G8 led to decreased intestinal cholesterol esterification and reduced cholesterol transport efficiency. Intestinal G5G8 appeared to limit the absorption of phytosterols; ACAT2 more efficiently esterified cholesterol than phytosterols. The data indicate that handling of sterols by the intestine involves both G5G8 and ACAT2 but that an additional factor (possibly Niemann-Pick C1-like 1) may be key in determining absorption efficiency. PMID:22669916

  9. Thermography Inspection for Detection and Tracking of Composite Cylinder Damage During Load Testing

    NASA Technical Reports Server (NTRS)

    Zalameda, J. N.; Winfree, W. P.; Seebo, J. P.; Johnston, P. H.

    2010-01-01

    Two thermography techniques, passive and active, are used to detect damage initiation and progression in a cyclically loaded composite cylinder. The passive thermography tracks damage progression in real time during cyclic loading. Active flash thermography, using a flash tube enclosed within the cylinder, images delaminations in a cylinder under different loads. A differential thermography processing technique eliminates normal material variations and improves sensitivity to and sizing of delaminations. The thermography results were compared to nonimmersion ultrasonic results.

  10. Airborne thermography or infrared remote sensing.

    PubMed

    Goillot, C C

    1975-01-01

    Airborne thermography is part of the more general remote sensing activity. The instruments suitable for image display are infrared line scanners. A great deal of interest has developed during the past 10 years in airborne thermal remote sensing and many applications are in progress. Infrared scanners on board a satellite are used for observation of cloud cover; airborne infrared scanners are used for forest fire detection, heat budget of soils, detecting insect attack, diseases, air pollution damage, water stress, salinity stress on vegetation, only to cite some main applications relevant to agronomy. Using this system it has become possible to get a 'picture' of our thermal environment.

  11. Infrared thermography in the restoration of cultural properties

    NASA Astrophysics Data System (ADS)

    Carlomagno, Giovanni M.; Carosena, Meola

    2001-03-01

    Some of the work carried out at DETEC on the use of infrared thermography in the architectural restoration field is examined. Three different techniques, pulse thermography (PT), modulated thermography (MT) and pulse phase thermography (PPT) are analyzed through the control of some art treasures such as mosaics and frescoes. In particular, the following artifacts are considered: mosaics covering some external walls of the building of the Faculty of Engineering of Naples, frescoes in the Duomo of Sarno, frescoes in the Cripta SS. Stefani in Vaste (Le), mosaics and frescoes in the Archeological Museum of Naples coming from Pompeii and Ruvo. It is found that the choice of the technique depends on the specific surface to be tested: if only qualitative information about detachments and cracks are needed the pulse thermography is sufficient; if the surface is not very sensitive to temperature rising, the pulse phase thermography can be applied which gives information about the location of the defected zone. If instead, the analysis regards rare art treasures, lockin thermography is the only response.

  12. Flash Infrared Thermography Contrast Data Analysis Technique

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay

    2014-01-01

    This paper provides information on an IR Contrast technique that involves extracting normalized contrast versus time evolutions from the flash thermography inspection infrared video data. The analysis calculates thermal measurement features from the contrast evolution. In addition, simulation of the contrast evolution is achieved through calibration on measured contrast evolutions from many flat-bottom holes in the subject material. The measurement features and the contrast simulation are used to evaluate flash thermography data in order to characterize delamination-like anomalies. The thermal measurement features relate to the anomaly characteristics. The contrast evolution simulation is matched to the measured contrast evolution over an anomaly to provide an assessment of the anomaly depth and width which correspond to the depth and diameter of the equivalent flat-bottom hole (EFBH) similar to that used as input to the simulation. A similar analysis, in terms of diameter and depth of an equivalent uniform gap (EUG) providing a best match with the measured contrast evolution, is also provided. An edge detection technique called the half-max is used to measure width and length of the anomaly. Results of the half-max width and the EFBH/EUG diameter are compared to evaluate the anomaly. The information provided here is geared towards explaining the IR Contrast technique. Results from a limited amount of validation data on reinforced carbon-carbon (RCC) hardware are included in this paper.

  13. Active thermography in qualitative evaluation of protective materials.

    PubMed

    Gralewicz, Grzegorz; Wiecek, Bogusław

    2009-01-01

    This is a study of the possibilities of a qualitative evaluation of protective materials with active thermography. It presents a simulation of a periodic excitation of a multilayer composite material. Tests were conducted with lock-in thermography on Kevlar composite consisting of 16 layers of Kevlar fabric reinforced with formaldehyde resin with implanted delamination defects. Lock-in thermography is a versatile tool for nondestructive evaluation. It is a fast, remote and nondestructive procedure. Hence, it was used to detect delaminations in the composite structure of materials used in the production of components designed for personal protection. This method directly contributes to an improvement in safety.

  14. Benefits of using infrared thermography in utility substations

    NASA Astrophysics Data System (ADS)

    Kregg, Michael A.

    2004-04-01

    One-way for a utility to deliver a superior product is for it to use infrared thermography (IR) as a preventative maintenance (PM) tool in its generating stations and on its transmission / distribution (T&D) system. Thermography"s use in a PM program can help avoid emergency restorations, identify additional issues to be addressed during routine maintenance, minimize component deterioration which extends component life cycle, and verify work performed as well as identify bad work practices. All these benefits lead to reduced utility maintenance costs and parts stock, and increased system reliability, utility and customer revenues, and utility customer retention.

  15. Extraction of thermal Green's function using diffuse fields: a passive approach applied to thermography

    NASA Astrophysics Data System (ADS)

    Capriotti, Margherita; Sternini, Simone; Lanza di Scalea, Francesco; Mariani, Stefano

    2016-04-01

    In the field of non-destructive evaluation, defect detection and visualization can be performed exploiting different techniques relying either on an active or a passive approach. In the following paper the passive technique is investigated due to its numerous advantages and its application to thermography is explored. In previous works, it has been shown that it is possible to reconstruct the Green's function between any pair of points of a sensing grid by using noise originated from diffuse fields in acoustic environments. The extraction of the Green's function can be achieved by cross-correlating these random recorded waves. Averaging, filtering and length of the measured signals play an important role in this process. This concept is here applied in an NDE perspective utilizing thermal fluctuations present on structural materials. Temperature variations interacting with thermal properties of the specimen allow for the characterization of the material and its health condition. The exploitation of the thermographic image resolution as a dense grid of sensors constitutes the basic idea underlying passive thermography. Particular attention will be placed on the creation of a proper diffuse thermal field, studying the number, placement and excitation signal of heat sources. Results from numerical simulations will be presented to assess the capabilities and performances of the passive thermal technique devoted to defect detection and imaging of structural components.

  16. Airborne thermography of temperature patterns in sugar beet piles

    NASA Technical Reports Server (NTRS)

    Moore, D. G.; Bichsel, S.

    1975-01-01

    An investigation was conducted to evaluate the use of thermography for locating spoilage areas (chimneys) within storage piles and to subsequently use the information for the scheduling of their processing. Thermal-infrared quantitative scanner data were acquired initially on January 16, 1975, over the storage piles at Moorhead, Minnesota, both during the day and predawn. Photographic data were acquired during the day mission to evaluate the effect of uneven snow cover on the thermal emittance, and the predawn thermography was used to locate potential chimneys. The piles were examined the day prior for indications of spoilage areas, and the ground crew indicated that no spoilage areas were located using their existing methods. Nine spoilage areas were interpreted from the thermography. The piles were rechecked by ground methods three days following the flights. Six of the nine areas delineated by thermography were actual spoilage areas.

  17. Infrared Thermography for Temperature Measurement and Non-Destructive Testing

    PubMed Central

    Usamentiaga, Rubèn; Venegas, Pablo; Guerediaga, Jon; Vega, Laura; Molleda, Julio; Bulnes, Francisco G.

    2014-01-01

    The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed. PMID:25014096

  18. Induction thermography for non-destructive evaluation of adhesive bonds

    NASA Astrophysics Data System (ADS)

    Balaji, L.; Balasubramaniam, Krishnan; Krishnamurthy, C. V.

    2013-01-01

    Adhesive bonding is widely used in automotive industry in the recent times. One of the major problems with adhesive bonds is the lack of a suitable non-destructive evaluation technique for assessing bonding. In this paper, an experimental study was carried out to apply induction thermography technique to evaluate adhesively bonded steel plates. Samples were fabricated with artificial defects such as air gap, foreign material, and improper adhesive filling. Induction thermography technique was found to detect defects and foreign inclusions. The sample specimen was also inspected using standard techniques such as Ultrasonic testing and Radiography testing. Defect detecting capabilities of the three techniques are compared. Induction thermography heating was FE modelled in 3D using COMSOL 3.5a. The simulated Induction thermography model was compared and validated with experimental results.

  19. Thermography in mass screening investigations of industrial workers

    NASA Astrophysics Data System (ADS)

    Chehter, A. I.; Ginsburg, L. I.; Traktinsky, A. G.

    1993-11-01

    The role of thermography in screening, directed to diagnose breast diseases, chronic tonsillitis, neurocirculatory dystonia, gall bladder dyskinesia, sinusitis, and to detect the character of influence of harmful factors on workers organisms is studied. The investigations demonstrate a possibility of a successful utilization of thermography in mass prophylactive examinations in order to diagnose these diseases, but the problem of breast tumors diagnostics demands the following investigations.

  20. Automated Spot Weld Inspection using Infrared Thermography

    SciTech Connect

    Chen, Jian; Zhang, Wei; Yu, Zhenzhen; Feng, Zhili

    2012-01-01

    An automated non-contact and non-destructive resistance spot weld inspection system based on infrared (IR) thermography was developed for post-weld applications. During inspection, a weld coupon was heated up by an auxiliary induction heating device from one side of the weld, while the resulting thermal waves on the other side were observed by an IR camera. The IR images were analyzed to extract a thermal signature based on normalized heating time, which was then quantitatively correlated to the spot weld nugget size. The use of normalized instead of absolute IR intensity was found to be useful in minimizing the sensitivity to the unknown surface conditions and environment interference. Application of the IR-based inspection system to different advanced high strength steels, thickness gauges and coatings were discussed.

  1. INFRARED THERMOGRAPHY OF CUTANEOUS MELANOMA METASTASES

    PubMed Central

    Shada, Amber L.; Dengel, Lynn T.; Petroni, Gina R.; Smolkin, Mark E.; Acton, Scott; Slingluff, Craig L.

    2014-01-01

    Background Differentiating melanoma metastasis from benign cutaneous lesions currently requires biopsy or costly imaging, such as positron emission tomography scans. Melanoma metastases have been observed to be subjectively warmer than similarly appearing benign lesions. We hypothesized that infrared (IR) thermography would be sensitive and specific in differentiating palpable melanoma metastases from benign lesions. Materials and methods Seventy-four patients (36 females and 38 males) had 251 palpable lesions imaged for this pilot study. Diagnosis was determined using pathologic confirmation or clinical diagnosis. Lesions were divided into size strata for analysis: 0–5, >5–15, >15–30, and >30 mm. Images were scored on a scale from −1 (colder than the surrounding tissue) to +3 (significantly hotter than the surrounding tissue). Sensitivity and specificity were calculated for each stratum. Logistical challenges were scored. Results IR imaging was able to determine the malignancy of small (0–5 mm) lesions with a sensitivity of 39% and specificity of 100%. For lesions >5–15 mm, sensitivity was 58% and specificity 98%. For lesions >15–30 mm, sensitivity was 95% and specificity 100%, and for lesions >30 mm, sensitivity was 78% and specificity 89%. The positive predictive value was 88%–100% across all strata, and the negative predictive value was 95% for >15–30 mm lesions and 80% for >30 mm lesions. Conclusions Malignant lesions >15 mm were differentiated from benign lesions with excellent sensitivity and specificity. IR imaging was well tolerated and feasible in a clinic setting. This pilot study shows promise in the use of thermography for the diagnosis of malignant melanoma with further potential as a noninvasive tool to follow tumor responses to systemic therapies. PMID:23043862

  2. Real Time Fatigue Damage Growth Assessment of a Composite Three-Stringer Panel Using Passive Thermography

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Burke, Eric R.; Horne, Michael R.; Bly, James B.

    2015-01-01

    Fatigue testing of advanced composite structures is critical to validate both structural designs and damage prediction models. In-situ inspection methods are necessary to track damage onset and growth as a function of load cycles. Passive thermography is a large area, noncontact inspection technique that is used to detect composite damage onset and growth in real time as a function of fatigue cycles. The thermal images are acquired in synchronicity to the applied compressive load using a dual infrared camera acquisition system for full (front and back) coverage. Image processing algorithms are investigated to increase defect contrast areas. The thermal results are compared to non-immersion ultrasound inspections and acoustic emission data.

  3. Optically and non-optically excited thermography for composites: A review

    NASA Astrophysics Data System (ADS)

    Yang, Ruizhen; He, Yunze

    2016-03-01

    Composites, such as glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP), and adhesive bonding are being increasingly used in fields of aerospace, renewable energy, civil and architecture, and other industries. Flaws and damages are inevitable during either fabrication or lifetime of composites structures or components. Thus, nondestructive testing (NDT) are extremely required to prevent failures and to increase reliability of composite structures or components in both manufacture and in-service inspection. Infrared thermography techniques including pulsed thermography, pulsed phase thermography, and lock-in thermography have shown the great potential and advantages. Besides conventional optical thermography, other sources such as laser, eddy current, microwave, and ultrasound excited thermography are drawing increasingly attentions for composites. In this work, a fully, in-depth and comprehensive review of thermography NDT techniques for composites inspection was conducted based on an orderly and concise literature survey and detailed analysis. Firstly, basic concepts for thermography NDT were defined and introduced, such as volume heating thermography. Next, the developments of conventional optic, laser, eddy current, microwave, and ultrasound thermography for composite inspection were reviewed. Then, some case studies for scanning thermography were also reviewed. After that, the strengths and limitations of thermography techniques were concluded through comparison studies. At last, some research trends were predicted. This work containing critical overview, detailed comparison and extensive list of references will disseminates knowledge between users, manufacturers, designers and researchers involved in composite structures or components inspection by means of thermography NDT techniques.

  4. Purification of Recombinant Acyl-Coenzyme A:Cholesterol Acyltransferase 1 (ACAT1) from H293 Cells and Binding Studies Between the Enzyme and Substrates Using Difference Intrinsic Fluorescence Spectroscopy†

    PubMed Central

    Chang, Catherine CY; Miyazaki, Akira; Dong, Ruhong; Kheirollah, Alireza; Yu, Chunjiang; Geng, Yong; Higgs, Henry N; Chang, Ta-Yuan

    2010-01-01

    Acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1) is a membrane bound enzyme utilizing long-chain fatty acyl-coenzyme A and cholesterol to form cholesteryl esters and coenzyme A. Previously, we had expressed tagged human ACAT1 (hACAT1) in CHO cells and purified it to homogeneity; however, only a sparse amount of purified protein could be obtained. Here we report that the hACAT1 expression level in H293 cells is 18-fold higher than that in CHO cells. We have developed a milder purification procedure to purify the enzyme to homogeneity. The abundance of the purified protein enabled us to conduct difference intrinsic fluorescence spectroscopy to study the binding between the enzyme and its substrates in CHAPS/phospholipid mixed micelles. The results show that oleoyl CoA binds to ACAT1 with Kd=1.9 μM, and elicits significant structural changes of the protein as manifested by the significantly positive changes in its fluorescence spectrum; stearoyl CoA elicits a similar spectrum change with much lower in magnitude. Previously, kinetic studies had shown that cholesterol is an efficient substrate and an allosteric activator of ACAT1, while its diastereomer epicholesterol is neither a substrate nor an activator. Here we show that both cholesterol and epicholesterol induce positive changes in the ACAT1 fluorescence spectrum; however, the magnitude of spectrum changes induced by cholesterol is much larger than epicholesterol. These results show that stereospecificity, governed by the 3beta-OH moiety in steroid ring A, plays an important role in the binding of cholesterol to ACAT1. PMID:20964445

  5. Particle image velocimetry and infrared thermography in a levitated droplet with nanosilica suspensions

    NASA Astrophysics Data System (ADS)

    Saha, Abhishek; Basu, Saptarshi; Kumar, Ranganathan

    2012-03-01

    Preferential accumulation and agglomeration kinetics of nanoparticles suspended in an acoustically levitated water droplet under radiative heating has been studied. Particle image velocimetry performed to map the internal flow field shows a single cell recirculation with increasing strength for decreasing viscosities. Infrared thermography and high speed imaging show details of the heating process for various concentrations of nanosilica droplets. Initial stage of heating is marked by fast vaporization of liquid and sharp temperature rise. Following this stage, aggregation of nanoparticles is seen resulting in various structure formations. At low concentrations, a bowl structure of the droplet is dominant, maintained at a constant temperature. At high concentrations, viscosity of the solution increases, leading to rotation about the levitator axis due to the dominance of centrifugal motion. Such complex fluid motion inside the droplet due to acoustic streaming eventually results in the formation of a ring structure. This horizontal ring eventually reorients itself due to an imbalance of acoustic forces on the ring, exposing larger area for laser absorption and subsequent sharp temperature rise.

  6. Breast cancer detection in rotational thermography images using texture features

    NASA Astrophysics Data System (ADS)

    Francis, Sheeja V.; Sasikala, M.; Bhavani Bharathi, G.; Jaipurkar, Sandeep D.

    2014-11-01

    Breast cancer is a major cause of mortality in young women in the developing countries. Early diagnosis is the key to improve survival rate in cancer patients. Breast thermography is a diagnostic procedure that non-invasively images the infrared emissions from breast surface to aid in the early detection of breast cancer. Due to limitations in imaging protocol, abnormality detection by conventional breast thermography, is often a challenging task. Rotational thermography is a novel technique developed in order to overcome the limitations of conventional breast thermography. This paper evaluates this technique's potential for automatic detection of breast abnormality, from the perspective of cold challenge. Texture features are extracted in the spatial domain, from rotational thermogram series, prior to and post the application of cold challenge. These features are fed to a support vector machine for automatic classification of normal and malignant breasts, resulting in a classification accuracy of 83.3%. Feature reduction has been performed by principal component analysis. As a novel attempt, the ability of this technique to locate the abnormality has been studied. The results of the study indicate that rotational thermography holds great potential as a screening tool for breast cancer detection.

  7. Crack depth determination with inductive thermography

    NASA Astrophysics Data System (ADS)

    Oswald-Tranta, B.; Schmidt, R.

    2015-05-01

    Castings, forgings and other steel products are nowadays usually tested with magnetic particle inspection, in order to detect surface cracks. An alternative method is active thermography with inductive heating, which is quicker, it can be well automated and as in this paper presented, even the depth of a crack can be estimated. The induced eddy current, due to its very small penetration depth in ferro-magnetic materials, flows around a surface crack, heating this selectively. The surface temperature is recorded during and after the short inductive heating pulse with an infrared camera. Using Fourier transformation the whole IR image sequence is evaluated and the phase image is processed to detect surface cracks. The level and the local distribution of the phase around a crack correspond to its depth. Analytical calculations were used to model the signal distribution around cracks with different depth and a relationship has been derived between the depth of a crack and its phase value. Additionally, also the influence of the heating pulse duration has been investigated. Samples with artificial and with natural cracks have been tested. Results are presented comparing the calculated and measured phase values depending on the crack depth. Keywords: inductive heating, eddy current, infrared

  8. Thermography applied acupuncture and qi-gong

    NASA Astrophysics Data System (ADS)

    Qin, Yuwen; Ji, Hong-Wei; Chen, Jin-Long; Li, Hong-Qi

    1997-04-01

    Thermographic technique can be used to measure temperature distribution of body surface in real-time, non-contact and full-field, which has been successfully used in medical diagnosis, remote sensing, and NDT, etc. The authors have developed a thermographic experiment that can be applied to inspect the effect of action of acupuncture and qi-gong (a system of deep breathing exercises) by measuring the temperature of hand and arm. The observation is performed respectively by thermography for the dynamic changes of temperature of the arm and hand after acupuncture therapy and qi-gong therapy. Thermographic results show that the temperature on the collateral channels increases markedly. In the meantime, it can be seen that the above therapies of Chinese medicine can stimulate the channel collateral system. This also contributes a new basis to the effect of action of the therapies of Chinese medicine. The work shows that thermographic technique is a powerful tool for research in Chinese medicine. In this paper, some thermal images are obtained from the persons treated with acupuncture and qi- gong.

  9. Time-resolved tribo-thermography

    NASA Astrophysics Data System (ADS)

    Dinwiddie, Ralph B.; Blau, Peter J.

    1999-03-01

    Wear of coated surfaces tends to progress through a series of stages in which damage accumulates until the coating fails to protect its substrate. Depending on the coating system and the contact conditions, these stages can sometimes be detected as a series of discrete periods of changing frictional behavior, or they can occur quite rapidly, leading to rapid removal of the coating. A new technique has been developed to capture magnified infrared (IR) images of a selected location on a moving wear surface and to synchronize these cycle-by-cycle images with the instantaneous friction force that occurs at the same location. A pin-on-disk tribometer has been used to demonstrate the principle, but other kinds of test geometries can also be used. Contrast in the IR images derives not only from the surface temperatures but also from the emissivity of surface features. A spatial calibration of the system allows the measurement of the width of the wear path as a function of time. By studying a series of captured and friction- synchronized images, it is possible to observe the detailed progression of wear and the corresponding frictional transitions in a limitless variety of materials. Examples of several different materials, including, steel, aluminum, brass, and paint, will be used to illustrate the application of time-resolved microscopic tribo-thermography to coatings research.

  10. Imaging Cracks by Laser Excited Thermography

    NASA Astrophysics Data System (ADS)

    Schlichting, J.; Kervalishvili, G. N.; Maierhofer, Ch.; Kreutzbruck, M.

    2010-02-01

    During the last years active thermography is increasingly used in a number of NDT problems in production and maintenance. In this work we focus on the detection of vertical cracks starting at the surface, which is an important indication of structural failure. By using local thermal excitation it is possible to image anisotropies in the lateral diffusivity by recording the temporal temperature data with an infrared camera. The regional transient behaviour of temperature distribution then can provide quantitative information of the crack parameter. In doing so, we present an advanced technique for the determination of the crack depth. The experimental set-up is based on an Nd:YAG laser. The beam is focused on the test sample by using an optical scanner to create the required lateral heat flow. The time resolved temperature distribution is recorded with an infrared camera (InSb FPA, 3 to 5 μm) providing a frame rate of up to 500 Hz. In addition we report on numerical simulation to investigate the concept of local heat excitation for a quantitative estimation of crack parameters. The modeling also includes the influence of surface to surface radiation inside the crack. We obtained a good consistency between experimental and theoretical data.

  11. Medical applications of infrared thermography: A review

    NASA Astrophysics Data System (ADS)

    Lahiri, B. B.; Bagavathiappan, S.; Jayakumar, T.; Philip, John

    2012-07-01

    Abnormal body temperature is a natural indicator of illness. Infrared thermography (IRT) is a fast, passive, non-contact and non-invasive alternative to conventional clinical thermometers for monitoring body temperature. Besides, IRT can also map body surface temperature remotely. Last five decades witnessed a steady increase in the utility of thermal imaging cameras to obtain correlations between the thermal physiology and skin temperature. IRT has been successfully used in diagnosis of breast cancer, diabetes neuropathy and peripheral vascular disorders. It has also been used to detect problems associated with gynecology, kidney transplantation, dermatology, heart, neonatal physiology, fever screening and brain imaging. With the advent of modern infrared cameras, data acquisition and processing techniques, it is now possible to have real time high resolution thermographic images, which is likely to surge further research in this field. The present efforts are focused on automatic analysis of temperature distribution of regions of interest and their statistical analysis for detection of abnormalities. This critical review focuses on advances in the area of medical IRT. The basics of IRT, essential theoretical background, the procedures adopted for various measurements and applications of IRT in various medical fields are discussed in this review. Besides background information is provided for beginners for better understanding of the subject.

  12. Defect characterisation based on heat diffusion using induction thermography testing.

    PubMed

    He, Yunze; Pan, Mengchun; Luo, Feilu

    2012-10-01

    Pulsed eddy current (PEC) thermography (a.k.a. induction thermography) has been successfully applied to detect defects (corrosion, cracks, impact, and delamination) in metal alloy and carbon fiber reinforced plastic. During these applications, the defect detection mechanism is mainly investigated based on the eddy current interaction with defect. In this paper, defect characterisation for wall thinning defect and inner defect in steel is investigated based on heat diffusion. The paper presents the PEC thermography testing, which integrates the reflection mode and transmission mode by means of configuring two cameras on both sides of sample. The defect characterisation methods under transmission mode and reflection mode are investigated and compared through 1D analytical analysis, 3D numerical studies, and experimental studies. The suitable detection mode for wall thinning and inner defects quantification is concluded.

  13. Defect characterisation based on heat diffusion using induction thermography testing

    NASA Astrophysics Data System (ADS)

    He, Yunze; Pan, Mengchun; Luo, Feilu

    2012-10-01

    Pulsed eddy current (PEC) thermography (a.k.a. induction thermography) has been successfully applied to detect defects (corrosion, cracks, impact, and delamination) in metal alloy and carbon fiber reinforced plastic. During these applications, the defect detection mechanism is mainly investigated based on the eddy current interaction with defect. In this paper, defect characterisation for wall thinning defect and inner defect in steel is investigated based on heat diffusion. The paper presents the PEC thermography testing, which integrates the reflection mode and transmission mode by means of configuring two cameras on both sides of sample. The defect characterisation methods under transmission mode and reflection mode are investigated and compared through 1D analytical analysis, 3D numerical studies, and experimental studies. The suitable detection mode for wall thinning and inner defects quantification is concluded.

  14. Infrared thermography on ocular surface temperature: A review

    NASA Astrophysics Data System (ADS)

    Tan, Jen-Hong; Ng, E. Y. K.; Rajendra Acharya, U.; Chee, C.

    2009-07-01

    Body temperature is a good indicator of human health. Thermal imaging system (thermography) is a non-invasive imaging procedure used to record the thermal patterns using Infrared (IR) camera. It provides visual and qualitative documentation of temperature changes in the vascular tissues, and is beginning to play an important role in the field of ophthalmology. This paper deals with the working principle, use and advantages of IR thermography in the field of ophthalmology. Different algorithms to acquire the ocular surface temperature (OST), that can be used for the diagnosis of ocular diseases are discussed.

  15. Computer Assisted Thermography And Its Application In Ovulation Detection

    NASA Astrophysics Data System (ADS)

    Rao, K. H.; Shah, A. V.

    1984-08-01

    Hardware and software of a computer-assisted image analyzing system used for infrared images in medical applications are discussed. The application of computer-assisted thermography (CAT) as a complementary diagnostic tool in centralized diagnostic management is proposed. The authors adopted 'Computer Assisted Thermography' to study physiological changes in the breasts related to the hormones characterizing the menstrual cycle of a woman. Based on clinical experi-ments followed by thermal image analysis, they suggest that 'differential skin temperature (DST)1 be measured to detect the fertility interval in the menstrual cycle of a woman.

  16. Mapping Surface Temperature on Biological Tissues by Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya; Chen, Yichao; Bartels, Kenneth; Wicksted, James; Chen, Wei

    2007-03-01

    In this paper, non-contact and noninvasive infrared thermography in the measurement of skin temperature on a mice model during dye-enhanced laser-tumor treatment coupled with the immunological response is explored. Mice with mammary tumors are injected with light absorption enhancing dye (indocyanine green, ICG) and immunoadjuvant (glycated chitosan, GC) prior to laser light (805 nm) irradiation through optical fiber. Using an infrared temperature probe, images are acquired and analyzed to determine surface temperature measurements. Simulations of the surface temperature measurements are conducted using a Monte Carlo finite difference method. The simulation results are in good agreement with the thermography measurements.

  17. IR Thermography of International Space Station Radiator Panels

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay; Winfree, WIlliam; Morton, Richard; Howell, Patricia

    2010-01-01

    Several non-flight qualification test radiators were inspected using flash thermography. Flash thermography data analysis used raw and second derivative images to detect anomalies (Echotherm and Mosaic). Simple contrast evolutions were plotted for the detected anomalies to help in anomaly characterization. Many out-of-family indications were noted. Some out-of-family indications were classified as cold spot indications and are due to additional adhesive or adhesive layer behind the facesheet. Some out-of-family indications were classified as hot spot indications and are due to void, unbond or lack of adhesive behind the facesheet. The IR inspection helped in assessing expected manufacturing quality of the radiators.

  18. Heat flux sensors for infrared thermography in convective heat transfer.

    PubMed

    Carlomagno, Giovanni Maria; de Luca, Luigi; Cardone, Gennaro; Astarita, Tommaso

    2014-11-07

    This paper reviews the most dependable heat flux sensors, which can be used with InfraRed (IR) thermography to measure convective heat transfer coefficient distributions, and some of their applications performed by the authors' research group at the University of Naples Federico II. After recalling the basic principles that make IR thermography work, the various heat flux sensors to be used with it are presented and discussed, describing their capability to investigate complex thermo-fluid-dynamic flows. Several applications to streams, which range from natural convection to hypersonic flows, are also described.

  19. Nondestructive evaluation technique using infrared thermography and terahertz imaging

    NASA Astrophysics Data System (ADS)

    Sakagami, Takahide; Shiozawa, Daiki; Tamaki, Yoshitaka; Iwama, Tatsuya

    2016-05-01

    Nondestructive testing (NDT) techniques using pulse heating infrared thermography and terahertz (THz) imaging were developed for detecting deterioration of oil tank floor, such as blister and delamination of corrosion protection coating, or corrosion of the bottom steel plate under coating. Experimental studies were conducted to demonstrate the practicability of developed techniques. It was found that the pulse heating infrared thermography was utilized for effective screening inspection and THz-TDS imaging technique performed well for the detailed inspection of coating deterioration and steel corrosion.

  20. Heat Flux Sensors for Infrared Thermography in Convective Heat Transfer

    PubMed Central

    Carlomagno, Giovanni Maria; de Luca, Luigi; Cardone, Gennaro; Astarita, Tommaso

    2014-01-01

    This paper reviews the most dependable heat flux sensors, which can be used with InfraRed (IR) thermography to measure convective heat transfer coefficient distributions, and some of their applications performed by the authors' research group at the University of Naples Federico II. After recalling the basic principles that make IR thermography work, the various heat flux sensors to be used with it are presented and discussed, describing their capability to investigate complex thermo-fluid-dynamic flows. Several applications to streams, which range from natural convection to hypersonic flows, are also described. PMID:25386758

  1. Avasimibe, an ACAT inhibitor, enhances the lipid lowering effect of atorvastatin in subjects with homozygous familial hypercholesterolemia.

    PubMed

    Raal, Frederick J; Marais, A David; Klepack, Ellen; Lovalvo, Jennifer; McLain, Richard; Heinonen, Therese

    2003-12-01

    This study assessed the efficacy and safety of avasimibe (CI-1011), an inhibitor of acyl coenzyme A-cholesterol acyltransferase (ACAT) in subjects with homozygous familial hypercholesterolemia (HoFH). Twenty seven subjects were enrolled in a double-blind, randomized, 3-sequence crossover trial of atorvastatin 80 mg QD, avasimibe 750 mg QD, and the combined treatment of atorvastatin 80 mg QD and avasimibe 750 mg QD after a washout period of 4 weeks. Each treatment period was administered over 6 weeks for a total of 18 weeks. There were no significant lipid changes resulting from the administration of avasimibe monotherapy. Avasimibe in combination with atorvastatin resulted in a significantly better reduction of total cholesterol (TC) as compared to atorvastatin alone (-22% versus -18%) (P < 0.05). All other lipid changes were not statistically significant for combination therapy compared to atorvastatin monotherapy, however there were greater reductions in triglycerides (TG) (-24% versus -13%), low-density lipoprotein cholesterol (LDL-C) (-23% versus -19%), very low-density lipoprotein cholesterol (VLDL-C) (-24% versus -13%) and high-density lipoprotein cholesterol (HDL-C) (-11% versus -6%). Avasimibe may modestly enhance the lipid-reducing effect of atorvastatin by further inhibiting the production of intracellular cholesterol through mechanisms that appear to be compatible in this population. PMID:14644397

  2. Inspecting thermal barrier coatings by IR thermography

    NASA Astrophysics Data System (ADS)

    Bison, Paolo G.; Marinetti, Sergio; Grinzato, Ermanno G.; Vavilov, Vladimir P.; Cernuschi, Federico; Robba, Daniele

    2003-04-01

    As far as power generation is concerned, coating technologies find the main and more advanced applications. Nowadays, superalloys available for manufacturing hot path components in gas turbine like combustion liners, blades and vanes can not sustain temperatures up to 1100°C. In order to guarantee a significative temperature drop ceramic thermal barrier coatings are deposited onto the metallic core. The thickness of thermal barrier coatings (TBC) ranges from a few hundreds microns up to 1 millimetre or more, depending on component and deposition technique (mainly Air Plasma Spray or Electron Beam Physical Vapour Deposition). The structural integrity of both the substrate and the coating and their mutual adhesion is a key point because any loss of the protective layer exposes the bulk material to an extremely aggressive environment in terms of oxidation and temperature. Therefore, TBC must be tested for detecting of defects during both quality control and periodic in-service inspections. Because of the key role played by thickness and low thermal diffusivity of TBC in the decreasing of the substrate material temperature, both delaminations and thickness variation must be detected and classified. Pulsed Thermography has been successfully applied to this application field. Nevertheless, the procedure gives ambiguous results when thickness or thermal properties change in a continuous way within the thermal barrier. In this paper, a specific study on the detection performances of NDE techniques is presented, even when a non-uniform TBC thickness is superimposed to the disbonding defect. Tests performed at workshop on real and specifically manufactured components are reported. Dedicated processing algorithms improving the test reliability and effectiveness are presented as well. Tests on real components on the field are also reported.

  3. NASA MUST Paper: Infrared Thermography of Graphite/Epoxy

    NASA Technical Reports Server (NTRS)

    Comeaux, Kayla; Koshti, Ajay

    2010-01-01

    The focus of this project is to use Infrared Thermography, a non-destructive test, to detect detrimental cracks and voids beneath the surface of materials used in the space program. This project will consist of developing a simulation model of the Infrared Thermography inspection of the Graphite/Epoxy specimen. The simulation entails finding the correct physical properties for this specimen as well as programming the model for thick voids or flat bottom holes. After the simulation is completed, an Infrared Thermography inspection of the actual specimen will be made. Upon acquiring the experimental test data, an analysis of the data for the actual experiment will occur, which includes analyzing images, graphical analysis, and analyzing numerical data received from the infrared camera. The simulation will then be corrected for any discrepancies between it and the actual experiment. The optimized simulation material property inputs can then be used for new simulation for thin voids. The comparison of the two simulations, the simulation for the thick void and the simulation for the thin void, provides a correlation between the peak contrast ratio and peak time ratio. This correlation is used in the evaluation of flash thermography data during the evaluation of delaminations.

  4. Use of aerial thermography in Canadian energy conservation programs

    NASA Technical Reports Server (NTRS)

    Cihlar, J.; Brown, R. J.; Lawrence, G.; Barry, J. N.; James, R. B.

    1977-01-01

    Recent developments in the use of aerial thermography in energy conservation programs within Canada were summarized. Following a brief review of studies conducted during the last three years, methodologies of data acquisition, processing, analysis and interpretation was discussed. Examples of results from an industrial oriented project were presented and recommendations for future basic work were outlined.

  5. Infrared thermography for CFRP inspection: computational model and experimental results

    NASA Astrophysics Data System (ADS)

    Fernandes, Henrique C.; Zhang, Hai; Morioka, Karen; Ibarra-Castanedo, Clemente; López, Fernando; Maldague, Xavier P. V.; Tarpani, José R.

    2016-05-01

    Infrared Thermography (IRT) is a well-known Non-destructive Testing (NDT) technique. In the last decades, it has been widely applied in several fields including inspection of composite materials (CM), specially the fiber-reinforced polymer matrix ones. Consequently, it is important to develop and improve efficient NDT techniques to inspect and assess the quality of CM parts in order to warranty airworthiness and, at the same time, reduce costs of airline companies. In this paper, active IRT is used to inspect carbon fiber-reinforced polymer (CFRP) at laminate with artificial inserts (built-in sample) placed on different layers prior to the manufacture. Two optical active IRT are used. The first is pulsed thermography (PT) which is the most widely utilized IRT technique. The second is a line-scan thermography (LST) technique: a dynamic technique, which can be employed for the inspection of materials by heating a component, line-by-line, while acquiring a series of thermograms with an infrared camera. It is especially suitable for inspection of large parts as well as complex shaped parts. A computational model developed using COMSOL Multiphysics® was used in order to simulate the inspections. Sequences obtained from PT and LST were processed using principal component thermography (PCT) for comparison. Results showed that it is possible to detect insertions of different sizes at different depths using both PT and LST IRT techniques.

  6. Defect Detection in Composite Coatings by Computational Simulation Aided Thermography

    NASA Astrophysics Data System (ADS)

    Almeida, R. M.; Souza, M. P. V.; Rebello, J. M. A.

    2010-02-01

    Thermography is based on the measurement of superficial temperature distribution of an object inspected subjected to tension, normally thermal heat. This measurement is performed with a thermographic camera that detects the infrared radiation emitted by every object. In this work thermograph was simulated by COMSOL software for optimize experimental parameters in composite material coatings inspection.

  7. Heat transfer investigation in pipe by IR thermography

    NASA Astrophysics Data System (ADS)

    Koppel, Tiit; Ainola, Leo; Ekholm, Ari; Lahdeniemi, Matti

    2000-03-01

    The IR-thermography has proved to be a useful contactless instrument in fluid flow research, especially for investigation of heat transfer processes. Series of experimental measurements of suddenly accelerated and pulsating pipe flow were made at Satakunta Polytechnic, Technology in Pori, Finland, with this aim.

  8. Concept And Development Of Instruments For ITER Thermography

    SciTech Connect

    Reichle, R.; Balorin, C.; Carpentier, S.; Corre, Y.; Davi, M.; Delchambre, E.; Desgrange, C.; Escourbiac, F.; Fougerolle, S.; Gardarein, J. L.; Gauthier, E.; Guilhem, D.; Jouve, M.; Loarer, Th.; Martins, J. P.; Patterlini, J. C.; Pocheau, C.; Roche, H.; Salasca, S.; Travere, J. M.

    2008-03-12

    We give here a short overview of the status of the development for ITER thermography as performed by the CEA-Cadarache and some of its collaboration partners. The topics that have been included in this synthesis are the status of the optical design, the role of multi-wavelength mesurements, multicolour pyroreflectometry, photothermal methods, and reflection simulations and measurements.

  9. Investigation on choosing technical parameters for pulse thermography

    NASA Astrophysics Data System (ADS)

    Li, Huijuan

    2015-04-01

    Composite material connected by glue has gained popularity as a replacement for conventional materials and structures to reduce weight and improve strength in the aerospace industry, with the development of material science and structural mechanics. However, the adhesive bonding process is more susceptible to quality variations during manufacturing than traditional joining methods. The integrality, strength and rigidity of product would be broken by disbonding. Infrared thermography is one of several non-destructive testing techniques which can be used for defect detection in aircraft materials. Pulsed infrared thermography has been widely used in aerospace and mechanical manufacture industry because it can offer noncontact, quickly and visual examinations of disbonding defects. However the parameter choosing method is difficult to decide. Investigate the choosing technical parameters for pulse thermograpghy is more important to ensure the product quality and testing efficiency. In this paper, two kinds of defects which are of various size, shape and location below the test surface are planted in the honeycomb structure, they are all tested by pulsed thermography. This paper presents a study of single factor experimental research on damage sample in simulation was carried out. The impact of the power of light source, detection distance, and the wave band of thermography camera on detecting effect is studied. The select principle of technique is made, the principle supplied basis for selection of detecting parameters in real part testing.

  10. Shuttle Entry Imaging Using Infrared Thermography

    NASA Technical Reports Server (NTRS)

    Horvath, Thomas; Berry, Scott; Alter, Stephen; Blanchard, Robert; Schwartz, Richard; Ross, Martin; Tack, Steve

    2007-01-01

    imaging platforms used within DoD along with agency assets developed and optimized for use during Shuttle ascent to demonstrate capability (i.e., tracking, acquisition of multispectral data, spatial resolution) and identify system limitations (i.e., radiance modeling, saturation) using state-of-the-art imaging instrumentation and communication systems. Global infrared intensity data have been transformed to temperature by comparison to Shuttle flight thermocouple data. Reasonable agreement is found between the flight thermography images and numerical prediction. A discussion of lessons learned and potential application to a potential Shuttle boundary layer transition flight test is presented.

  11. Integration of ground-penetrating radar, ultrasonic tests and infrared thermography for the analysis of a precious medieval rose window

    NASA Astrophysics Data System (ADS)

    Nuzzo, L.; Calia, A.; Liberatore, D.; Masini, N.; Rizzo, E.

    2010-04-01

    The integration of high-resolution, non-invasive geophysical techniques (such as ground-penetrating radar or GPR) with emerging sensing techniques (acoustics, thermography) can complement limited destructive tests to provide a suitable methodology for a multi-scale assessment of the state of preservation, material and construction components of monuments. This paper presents the results of the application of GPR, infrared thermography (IRT) and ultrasonic tests to the 13th century rose window of Troia Cathedral (Apulia, Italy), affected by widespread decay and instability problems caused by the 1731 earthquake and reactivated by recent seismic activity. This integrated approach provided a wide amount of complementary information at different scales, ranging from the sub-centimetre size of the metallic joints between the various architectural elements, narrow fractures and thin mortar fillings, up to the sub-metre scale of the internal masonry structure of the circular ashlar curb linking the rose window to the façade, which was essential to understand the original building technique and to design an effective restoration strategy.

  12. Correlation of infrared thermographic patterns and acoustic emission signals with tensile deformation and fracture processes

    NASA Astrophysics Data System (ADS)

    Venkataraman, B.; Raj, Baldev; Mukhopadhyay, C. K.; Jayakumar, T.

    2001-04-01

    During tensile deformation, part of the mechanical work done on the specimen is transformed into heat and acoustic activity. The amount of acoustic activity and the thermal emissions depend on the test conditions and the deformation behavior of the specimen during loading. Authors have used thermography and acoustic emission (AE) simultaneously for monitoring tensile deformation in AISI type 316 SS. Tensile testing was carried out at 298 K at three different strain rates. It has been shown that the simultaneous use of these techniques can provide complementary information for characterizing the tensile deformation and fracture processes.

  13. Divertor IR thermography on Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Terry, J. L.; LaBombard, B.; Brunner, D.; Payne, J.; Wurden, G. A.

    2010-10-01

    Alcator C-Mod is a particularly challenging environment for thermography. It presents issues that will similarly face ITER, including low-emissivity metal targets, low-Z surface films, and closed divertor geometry. In order to make measurements of the incident divertor heat flux using IR thermography, the C-Mod divertor has been modified and instrumented. A 6° toroidal sector has been given a 2° toroidal ramp in order to eliminate magnetic field-line shadowing by imperfectly aligned divertor tiles. This sector is viewed from above by a toroidally displaced IR camera and is instrumented with thermocouples and calorimeters. The camera provides time histories of surface temperatures that are used to compute incident heat-flux profiles. The camera sensitivity is calibrated in situ using the embedded thermocouples, thus correcting for changes and nonuniformities in surface emissivity due to surface coatings.

  14. Developing written inspection procedures for thermal/infrared thermography

    SciTech Connect

    Snell, J.

    1996-12-31

    Written inspection procedures are essential to acquiring valid data on a repeatable basis. They are also vital to the safety of the thermographer, and may, for that reason alone, be required by a company. Many thermographers are working with no written procedures. To date only a few of the necessary procedures have been developed by recognized standards organizations. The lack of procedures is limiting the use of thermography. Where thermography is being used without them, results are often less than optimum. This paper will (1) survey existing procedures and standards; (2) discuss current efforts by standards organizations to develop standards and procedures; and (3) present a general methodology from which written inspection procedures can be developed for many thermographic inspections.

  15. International standards pertaining to thermography practices, training and certification

    NASA Astrophysics Data System (ADS)

    West Åkerblom, Lisa

    2008-03-01

    American, European and International societies establish standards for individuals and companies within the field of infrared thermography. Historically addressing non-destructive testing (NDT) applications and personnel, standards exist and are being developed within the fields of condition monitoring (CM) and building diagnostics. Incorrect reference to or application of standards and guidelines create widespread market confusion. What type of claim can be made against which standards? Does the standard apply to a company or an individual? To what or whom is the standard intended? Does reference to a standard guarantee compliance or imply quality? How does one become educated or involved in standards? An overview of international standards within the field of thermography (with brief reference to recognizable guidelines and standards such as ASNT SNT-TC-1A and CEN 473), their status and application will be presented.

  16. Eddy current pulsed phase thermography and feature extraction

    NASA Astrophysics Data System (ADS)

    He, Yunze; Tian, GuiYun; Pan, Mengchun; Chen, Dixiang

    2013-08-01

    This letter proposed an eddy current pulsed phase thermography technique combing eddy current excitation, infrared imaging, and phase analysis. One steel sample is selected as the material under test to avoid the influence of skin depth, which provides subsurface defects with different depths. The experimental results show that this proposed method can eliminate non-uniform heating and improve defect detectability. Several features are extracted from differential phase spectra and the preliminary linear relationships are built to measure these subsurface defects' depth.

  17. Airborne thermography for condition monitoring of a public baths building

    NASA Astrophysics Data System (ADS)

    Mattsson, Mats; Hellman, Erik; Ljungberg, Sven-Ake

    2001-03-01

    Airborne and ground-based thermography surveys have been performed in order to detect moisture and energy related problems in the construction of a public swimming bath building. This paper describes the information potential and the advantages and limitations using a standard IR-camera and traditional inspection methods to gather information for retrofit priorities. The damage conditions indicated in the thermal images are confirmed by field inspections and photographic documentation.

  18. Efficiency of thermography in the study of hydrological connectivity

    NASA Astrophysics Data System (ADS)

    Cantreul, Vincent; Burgeon, Victor; Triquet, Johan; Tuerlinck, Manon; Vaelen, Guillaume; Leemans, Vincent; Degré, Aurore

    2016-04-01

    Hydrologic connectivity is an emerging concept which permits deeper understanding of catchments behavior. However, the measurements of functional connectivity is complex and still needs new developments in order to approach the « dynamic » part of the story. This study aims at assessing the efficiency of thermography to analyze hydrologic connectivity in an agricultural catchment in Belgium (loamy soils). Tests have been performed on experimental tubs at first and on field at second. Under controlled conditions, hot milk was spread on an experimental tub with bare soil and grass. The hot milk permits to compare color tracer with thermic one. The results are quite good. The binarization of pictures from usual camera and from thermic one gives similar percentage of runoff coverage at same locations. The mean difference is about 8% for bare soils and 10% for planted grass. There is a slight overestimation with thermic camera because of time delay of soil cooling after milk passing. In the same time in the planted grass, there are some runoff pixels which are hidden by vegetation. On field, blue colored water was used to simulate a rainfall on a field covered with mustard and on the same field without any coverage. Where runoff flows, the soil appears warmer because of heat extracted by water in the soil. The results comparing visual and thermic pictures are more nuanced. The mean difference reaches 30% on bare soil. Indeed, (i) the rainfall drops seem to hide the runoff during the rain; (ii) the vegetation density (mustard) is quite a problem for runoff detection. However, the difference between successive time pictures permits to distinguish flow paths easily. In conclusion, thermography stands as a good alternative for connectivity study. It's obviously a preliminary study which gives some indications of the possible use of thermography. At present, we are testing real rainfalls (different types) with different camera's positions and different land use (different

  19. Laser active thermography for non-destructive testing

    NASA Astrophysics Data System (ADS)

    Semerok, A.; Grisolia, C.; Fomichev, S. V.; Thro, P.-Y.

    2013-11-01

    Thermography methods have found their applications in different fields of human activity. The non-destructive feature of these methods along with the additional advantage by automated remote control and tests of nuclear installations without personnel attendance in the contaminated zone are of particular interest. Laser active pyrometry and laser lock-in thermography for in situ non-destructive characterization of micrometric layers on graphite substrates from European tokamaks were under extensive experimental and theoretical studies in CEA (France). The studies were aimed to obtain layer characterization with cross-checking the layer thermal contact coefficients determined by active laser pyrometry and lock-in thermography. The experimental installation comprised a Nd-YAG pulsed repetition rate laser (1 Hz - 10 kHz repetition rate frequency, homogeneous spot) and a home-made pyrometer system based on two pyrometers for the temperature measurements in 500 - 2600 K range. For both methods, the layer characterization was provided by the best fit of the experimental results and simulations. The layer thermal contact coefficients determined by both methods were quite comparable. Though there was no gain in the measurements accuracy, lock-in measurements have proved their advantage as being much more rapid. The obtained experimental and theoretical results are presented. Some practical applications and possible improvements of the methods are discussed.

  20. Inspection of composite structures using line scanning thermography

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Butera, Manny; Godinez, Valery

    2012-06-01

    This work deals with the non destructive analysis of different composite parts and structures using Line Scanning Thermography (LST), a non-contact inspection method based in dynamic thermography. The LST technique provides a quick and efficient methodology to scan wide areas rapidly; the technique has been used on the inspection of composite propellers, sandwich panels, motor case tubes and wind turbine blades, among others. In LST a line heat source is used to thermally excite the surface under study while an infrared detector records the transient surface temperature variation of the heated region. Line Scanning Thermography (LST), has successfully been applied to determine the thickness of metallic plates and to assess boiler tube thinning. In this paper the LST protocols developed for the detection of sub-surface defects in different composite materials commonly used in aerospace applications, plates will be presented. In most cases the thermal images acquired using LST will be compared with ultrasonic c-scans. The fundamentals of LST will be discussed, as well as the limitations of this technique for NDT inspection.

  1. Application of IR thermography for unsteady fluid-flow research

    NASA Astrophysics Data System (ADS)

    Koppel, Tiit; Lahdeniemi, Matti; Ekholm, Ari

    1998-03-01

    In the recent years the IR thermography technique has been sued successfully as a new contactless instrument for gas and fluid flow research in pipes and on the surface of a flat plate. It is well known that most energy changes in the flow take place in the boundary layer. This is in turn important for the intensity of convective heat transfer in pipe flows and enables to measure processes connected with energy changes in the flow from outside the pipe. Series of measurements of suddenly accelerated and pulsating pipe flow were made at Satakunta Polytechnic, Technology Pori, Finland. The theoretical criterion describing the transition from laminar to turbulent regime is found depending on the critical thickness of the boundary layer of suddenly accelerated flow. At the moment of transition of the 'plug' type flow into turbulent flow, the velocities in the wall region diminish and this can be detected using the IR thermography from the wall temperature changes. the experimental results of the mean velocity development and transition criteria correspond to the theoretical calculations. The changes of the internal structure of the flow affect the convective heat transfer and this in turn influences the pipe wall temperature. IR thermography measures pipe wall temperature changes and consequently we can detect flow structure changes in the boundary layer in the accelerated and decelerated phase of the pulsating pipe flow.

  2. Infrared Contrast Analysis Technique for Flash Thermography Nondestructive Evaluation

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay

    2014-01-01

    The paper deals with the infrared flash thermography inspection to detect and analyze delamination-like anomalies in nonmetallic materials. It provides information on an IR Contrast technique that involves extracting normalized contrast verses time evolutions from the flash thermography infrared video data. The paper provides the analytical model used in the simulation of infrared image contrast. The contrast evolution simulation is achieved through calibration on measured contrast evolutions from many flat bottom holes in the subject material. The paper also provides formulas to calculate values of the thermal measurement features from the measured contrast evolution curve. Many thermal measurement features of the contrast evolution that relate to the anomaly characteristics are calculated. The measurement features and the contrast simulation are used to evaluate flash thermography inspection data in order to characterize the delamination-like anomalies. In addition, the contrast evolution prediction is matched to the measured anomaly contrast evolution to provide an assessment of the anomaly depth and width in terms of depth and diameter of the corresponding equivalent flat-bottom hole (EFBH) or equivalent uniform gap (EUG). The paper provides anomaly edge detection technique called the half-max technique which is also used to estimate width of an indication. The EFBH/EUG and half-max width estimations are used to assess anomaly size. The paper also provides some information on the "IR Contrast" software application, half-max technique and IR Contrast feature imaging application, which are based on models provided in this paper.

  3. Applications of the thermography in the animal production

    NASA Astrophysics Data System (ADS)

    Piñeiro, Carlos; Vizcaino, Elena; Morales, Joaquín.; Manso, Alberto; Díaz, Immaculada; Montalvo, Gema

    2015-04-01

    Infrared thermography is a working technology for over decades, which have been applied mainly in the buildings. We want to move this use to the animal production in order to help us to detect problems of energy efficiency in the facilities preventing, for example, the animal's welfare. In animal production it is necessary to provide a suitable microclimate according to age and production stage of the animals. This microclimate is achieved in the facilities through the environment modification artificially, providing an appropriate comfort for the animals. Many of the problems detected in farms are related to a poor environmental management and control. This is where infrared thermography becomes an essential diagnostic tool to detect failures in the facilities that will be related with health and performance of the animals. The use of this technology in energy audits for buildings, facilities, etc. is becoming more frequent, enabling the technician to easily detect and assess the temperature and energy losses, and it can be used as a support to draft reports and to transmit the situation to the owner in a visual format. In this way, both will be able to decide what improvements are required. Until now, there was not an appropriate technology with affordable prices and easy to manage enough in order to allow the use of the thermography like a routine tool for the diagnostic of these problems, but currently there are some solutions which are starting to appear on the market to meet the requirements needed by the industry.

  4. Acoustical standards in engineering acoustics

    NASA Astrophysics Data System (ADS)

    Burkhard, Mahlon D.

    2001-05-01

    The Engineering Acoustics Technical Committee is concerned with the evolution and improvement of acoustical techniques and apparatus, and with the promotion of new applications of acoustics. As cited in the Membership Directory and Handbook (2002), the interest areas include transducers and arrays; underwater acoustic systems; acoustical instrumentation and monitoring; applied sonics, promotion of useful effects, information gathering and transmission; audio engineering; acoustic holography and acoustic imaging; acoustic signal processing (equipment and techniques); and ultrasound and infrasound. Evident connections between engineering and standards are needs for calibration, consistent terminology, uniform presentation of data, reference levels, or design targets for product development. Thus for the acoustical engineer standards are both a tool for practices, for communication, and for comparison of his efforts with those of others. Development of many standards depends on knowledge of the way products are put together for the market place and acoustical engineers provide important input to the development of standards. Acoustical engineers and members of the Engineering Acoustics arm of the Society both benefit from and contribute to the Acoustical Standards of the Acoustical Society.

  5. Acoustic Neuroma

    MedlinePlus

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. The tumor ... press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the symptoms ...

  6. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  7. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  8. Infrared thermography monitoring of the NaCl crystallisation process

    NASA Astrophysics Data System (ADS)

    Vázquez, Patricia; Thomachot-Schneider, Céline; Mouhoubi, Kamel; Fronteau, Gilles; Gommeaux, Maxime; Benavente, David; Barbin, Vincent; Bodnar, Jean-Luc

    2015-07-01

    In this work, we describe the growth of NaCl crystals by evaporating droplets of aqueous solution while monitoring them with infrared thermography. Over the course of the evaporation experiments, variations in the recorded signal were observed and interpreted as being the result of evaporation and crystallisation. In particular, we observed sharp and transient decreases in the thermosignal during the later stages of high-concentration drop evaporation. The number of such events per experiment, referred to as "pop-cold events", varied from 1 to over 100 and had durations from 1 to 15 s. These events are interpreted as a consequence from the top-supplied creeping (TSC) of the solution feeding the growth of efflorescence-like crystals. This phenomenon occurred when the solution was no longer macroscopically visible. In this case, efflorescence-like crystals with a spherulite shape grew around previously formed cubic crystals. Other crystal morphologies were also observed but were likely fed by mass diffusion or bottom-supplied creeping (BSC) and were not associated with "pop-cold events"; these morphologies included the cubic crystals at the centre, ring-shaped at the edge of droplets and fan-shaped crystals. After complete evaporation, an analysis of the numbers and sizes of the different types of crystals was performed using image processing. Clear differences in their sizes and distribution were observed in relation to the salt concentration. Infrared thermography permitted a level of quantification that previously was only possible using other techniques. As example, the intermittent efflorescence growth process was clearly observed and measured for the first time using infrared thermography.

  9. In-Flight Flow Visualization Using Infrared Thermography

    NASA Technical Reports Server (NTRS)

    vanDam, C. P.; Shiu, H. J.; Banks D. W.

    1997-01-01

    The feasibility of remote infrared thermography of aircraft surfaces during flight to visualize the extent of laminar flow on a target aircraft has been examined. In general, it was determined that such thermograms can be taken successfully using an existing airplane/thermography system (NASA Dryden's F-18 with infrared imaging pod) and that the transition pattern and, thus, the extent of laminar flow can be extracted from these thermograms. Depending on the in-flight distance between the F-18 and the target aircraft, the thermograms can have a spatial resolution of as little as 0.1 inches. The field of view provided by the present remote system is superior to that of prior stationary infrared thermography systems mounted in the fuselage or vertical tail of a subject aircraft. An additional advantage of the present experimental technique is that the target aircraft requires no or minimal modifications. An image processing procedure was developed which improves the signal-to-noise ratio of the thermograms. Problems encountered during the analog recording of the thermograms (banding of video images) made it impossible to evaluate the adequacy of the present imaging system and image processing procedure to detect transition on untreated metal surfaces. The high reflectance, high thermal difussivity, and low emittance of metal surfaces tend to degrade the images to an extent that it is very difficult to extract transition information from them. The application of a thin (0.005 inches) self-adhesive insulating film to the surface is shown to solve this problem satisfactorily. In addition to the problem of infrared based transition detection on untreated metal surfaces, future flight tests will also concentrate on the visualization of other flow phenomena such as flow separation and reattachment.

  10. Eddy current pulsed phase thermography for subsurface defect quantitatively evaluation

    NASA Astrophysics Data System (ADS)

    He, Yunze; Pan, Mengchun; Tian, GuiYun; Chen, Dixiang; Tang, Ying; Zhang, Hong

    2013-09-01

    This Letter verified eddy current pulse phase thermography through numerical and experimental studies. During the numerical studies, two characteristic features, blind frequency and min phase, were extracted from differential phase spectra, and their monotonic relationships with defects' depth under different heating time were compared. According to the numerical studies, 100 ms was employed as heating time during the improved experimental studies. The experimental results agreed with the numerical results. Based on their linear relationship with defects' depths, both features can be used to measure the defect's depth.

  11. Finite Element Modeling of Transient Thermography Inspection of Composite Materials

    NASA Technical Reports Server (NTRS)

    Chu, Tsuchin Philip

    1998-01-01

    Several finite element models of defects such as debond and void have been developed for composite panels subjected to transient thermography inspection. Since the exact nature of the heat generated from the flash lamps is unknown, direct comparison between FEA and experimental results is not possible. However, some similarity of the results has been observed. The shape of the time curve that simulates the heat flux from the flash lamps has minimal effect on the temperature profiles. Double the number of flash lamps could increase the contrast of thermal image and define the shape of defect better.

  12. Visualization of In-Flight Flow Phenomena Using Infrared Thermography

    NASA Technical Reports Server (NTRS)

    Banks, D. W.; vanDam, C. P.; Shiu, H. J.; Miller, G. M.

    2000-01-01

    Infrared thermography was used to obtain data on the state of the boundary layer of a natural laminar flow airfoil in supersonic flight. In addition to the laminar-to-turbulent transition boundary, the infrared camera was able to detect shock waves and present a time dependent view of the flow field. A time dependent heat transfer code was developed to predict temperature distributions on the test subject and any necessary surface treatment. A commercially available infrared camera was adapted for airborne use in this application. Readily available infrared technology has the capability to provide detailed visualization of various flow phenomena in subsonic to hypersonic flight regimes.

  13. Defect depth measurement of carbon fiber reinforced polymers by thermography

    NASA Astrophysics Data System (ADS)

    Chen, Terry Y.; Chen, Jian-Lun

    2016-01-01

    Carbon fiber reinforced polymers has been widely used in all kind of the industries. However the internal defects can result in the change of material or mechanical properties, and cause safety problem. In this study, step-heating thermography is employed to measure the time series temperature distribution of composite plate. The principle of heat conduction in a flat plate with defect inside is introduced. A temperature separation criterion to determine the depth of defect inside the specimen is obtained experimentally. Applying this criterion to CFRP specimens with embedded defects, the depth of embedded defect in CFRP can be determined quite well from the time series thermograms obtained experimentally.

  14. Crack detection using pulsed eddy current stimulated thermography

    SciTech Connect

    Kostson, E.; Weekes, B.; Almond, D. P.; Wilson, J.; Tian, G. Y.

    2011-06-23

    This contribution presents results from studies investigating factors that influence the detection of surface breaking cracks using pulsed eddy current thermography. The influences of the current strength and crack orientation in both ferromagnetic and non-ferromagnetic metals have been investigated. It has been found that crack detection is far more sensitive to crack orientation in non-ferromagnetic metals than in ferromagnetic metals. The effects of crack size on detectability are presented for a large number of steel, nickel alloy and titanium samples. Results of studies comparing crack images obtained prior and after coating a nickel alloy sample with a thermal barrier coating are presented.

  15. Infrared Thermography Applied to the Study of Cultural Heritage

    NASA Astrophysics Data System (ADS)

    Mercuri, F.; Cicero, C.; Orazi, N.; Paoloni, S.; Marinelli, M.; Zammit, U.

    2015-06-01

    Active infrared thermography is an important non-destructive technique frequently employed in the analysis of cultural heritage. For its capability to show subsurface features in the artifacts, this technique has been used to investigate various kinds of artifacts, composed of different structures and materials. In this work, an overview of its recent applications is presented. In particular, the detection of cold working features in bronze sculpture investigations, of buried features in ancient book bindings, such as their structural characteristics and written scraps re-used in their manufacturing process, and on the investigation of defects and inhomogeneities in illuminations, is reported.

  16. Eddy current step heating thermography for quantitatively evaluation

    NASA Astrophysics Data System (ADS)

    He, Yunze; Pan, Mengchun; Chen, Dixiang; Tian, GuiYun; Zhang, Hong

    2013-11-01

    This Letter proposed eddy current step heating thermography (ECSHT) combing eddy current excitation with SHT. It has been verified through numerical and experimental studies that the temperature-time1/2 curve can be used to detect the subsurface defects. Separation time was defined and extracted from temperature responses as characteristic feature. Experiment studies with mild steel sample were conducted, and the experimental results showed that two features representing separation time can be used to measure the defect's depth based on their linear relationships.

  17. Topological Acoustics

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-01

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

  18. Topological acoustics.

    PubMed

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-20

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

  19. State of the art of aerial thermography in Iceland: thermography of geothermal areas during the past 20 years

    NASA Astrophysics Data System (ADS)

    Bjornsson, Sigfus; Arnason, Kolbeinn

    1995-03-01

    Aerial thermography was first applied in Iceland in the early sixties in conjunction with the suboceanic eruption of Surtsey. The same technique was subsequently applied (in the late sixties, early seventies) to some major geothermal areas in Iceland. Although it gave a global view of heat on the surface, local geologists/geophysicists were not impressed by the inroad of this space technology. According to this view, the technique lacked sensitivity, resolution, means of calibration, and gave very distorted images. Although microwave remote sensing (applied in glaciology) and processing of Landsat data (including IR) was practiced, aerial thermography lay at rest in Iceland until the mid eighties, when it was taken up again first for demonstration purposes using an instrument we rented jointly with the Geodetic Institute, but later it would be based on our own developments. Our work being application driven, due to the way this development is financed, the emphasis in the late eighties/early nineties was mainly on the near infrared range. For the last three years it has shifted however towards the far infrared range again and focused on geothermal areas, both for scientific purposes as well as for natural heat reservoirs for distance heating networks. Aerial thermography of wide area natural heat and energy distribution networks sets stringent requirements, e.g. to sensitivity and temporal, spatial as well as spectral resolutions. Efforts to meet that goal in Iceland have led to new developments based on wide aperture line scanners covering swaths in the flight direction, frame based focal plane cameras and on improved signal processing and data processing procedures. A particular emphasis has been on error corrections due to unpredictable aircraft movements.

  20. 3D thermography imaging standardization technique for inflammation diagnosis

    NASA Astrophysics Data System (ADS)

    Ju, Xiangyang; Nebel, Jean-Christophe; Siebert, J. Paul

    2005-01-01

    We develop a 3D thermography imaging standardization technique to allow quantitative data analysis. Medical Digital Infrared Thermal Imaging is very sensitive and reliable mean of graphically mapping and display skin surface temperature. It allows doctors to visualise in colour and quantify temperature changes in skin surface. The spectrum of colours indicates both hot and cold responses which may co-exist if the pain associate with an inflammatory focus excites an increase in sympathetic activity. However, due to thermograph provides only qualitative diagnosis information, it has not gained acceptance in the medical and veterinary communities as a necessary or effective tool in inflammation and tumor detection. Here, our technique is based on the combination of visual 3D imaging technique and thermal imaging technique, which maps the 2D thermography images on to 3D anatomical model. Then we rectify the 3D thermogram into a view independent thermogram and conform it a standard shape template. The combination of these imaging facilities allows the generation of combined 3D and thermal data from which thermal signatures can be quantified.

  1. NDE of FRP Wrapped Timber Bridge Components Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Halabe, U. B.; Steele, W. E.; GangaRao, H. V. S.; Klinkhachorn, P.

    2003-03-01

    This paper presents the results of an experimental study on the use of infrared thermography technique for detection of subsurface debonds in fiber reinforced polymer (FRP) wrapped timber railroad bridge components. Simulated subsurface debonds were constructed in the laboratory in timber piles wrapped with FRP composite fabric. The debonds varied in size, thickness and severity. These debonds were placed between the 1/8″ thick FRP wrap and the timber surface. The thermal images from the delaminated specimens were compared with the thermal images from undamaged specimens to study the effect of subsurface debonds. In addition, several field tests were conducted using the infrared imaging system on three timber railroad bridges located in Moorefield, West Virginia that were rehabilitated with FRP composite fabric wraps. The field test data was used to detect any possible debond at the composite-timber interface and study the effect of environmental parameters on the infrared images. This study showed that the infrared thermography technique can be effectively used to detect subsurface debonds in timber components wrapped with FRP composite fabric. The study also shows the effect of different parameters (environmental conditions, heat source, etc.) on the infrared images.

  2. Noninvasive diagnosis of seed viability using infrared thermography

    PubMed Central

    Kranner, Ilse; Kastberger, Gerald; Hartbauer, Manfred; Pritchard, Hugh W.

    2010-01-01

    Recent advances in the noninvasive analyses of plant metabolism include stress imaging techniques, mainly developed for vegetative tissues. We explored if infrared thermography can be used to predict whether a quiescent seed will germinate or die upon water uptake. Thermal profiles of viable, aged, and dead Pisum sativum seeds were recorded, and image analysis of 22,000 images per individual seed showed that infrared thermography can detect imbibition- and germination-associated biophysical and biochemical changes. These “thermal fingerprints” vary with viability in this species and in Triticum aestivum and Brassica napus seeds. Thermogenesis of the small individual B. napus seeds was at the limit of the technology. We developed a computer model of “virtual pea seeds,” that uses Monte Carlo simulation, based on the heat production of major seed storage compounds to unravel physico-chemical processes of thermogenesis. The simulation suggests that the cooling that dominates the early thermal profiles results from the dissolution of low molecular-weight carbohydrates. Moreover, the kinetics of the production of such “cooling” compounds over the following 100 h is dependent on seed viability. We also developed a deterministic tool that predicts in the first 3 hours of water uptake, when seeds can be redried and stored again, whether or not a pea seed will germinate. We believe that the early separation of individual, ungerminated seeds (live, aged, or dead) before destructive germination assessment creates unique opportunities for integrative studies on cell death, differentiation, and development. PMID:20133712

  3. Identification of age degradation in EPROM chips using infrared thermography

    NASA Astrophysics Data System (ADS)

    Allred, Lloyd G.

    1998-03-01

    In a recent upgrade of the digital flight control computer for the F-16, there was serious consternation expressed about the quality of the soldering repair process. Dozens of circuit cards failed to function after the upgrade, even though all of these cards operated correctly before the modifications. The shop called for the use of the IR camera to assist in diagnosing and repairing these cards. What the Neural Radiant Energy Detection found was faulty and marginal chips.Of particular interest was the presence of degraded EPROM chips on the Program Memory cards. While it is known that EPROMs have a limited life cycle, the failure has been further characterized. Thermography provides a quantification of the degradation in thermal performance as the EPROMs are reused. Pristine EPROM chips have a rise rate of about 0.008 degrees C/sec. When the heat rates exceed 0.021 degrees C/sec, the EPROM chips will not accept a program. Some of the chips exhibited heat rates exceeding 0.1 degrees C/sec. Some chips with degradation of 0.018 degrees C/sec would accept a program, but fail other functional tests. What is clear from these results is that IR thermography can be used to identify degrading EPROM chips for replacement before failures become immanent.

  4. Karst Groundwater Hydrologic Analyses Based on Aerial Thermography

    NASA Technical Reports Server (NTRS)

    Campbell, C. Warren; Keith, A. G.

    2000-01-01

    On February 23, 1999, thermal imagery of Marshall Space Flight Center, Alabama was collected using an airborne thermal camera. Ground resolution was I in. Approximately 40 km 2 of thermal imagery in and around Marshall Space Flight Center (MSFC) was analyzed to determine the location of springs for groundwater monitoring. Subsequently, forty-five springs were located ranging in flow from a few ml/sec to approximately 280 liter/sec. Groundwater temperatures are usually near the mean annual surface air temperature. On thermography collected during the winter, springs show up as very warm spots. Many of the new springs were submerged in lakes, streams, or swamps; consequently, flow measurements were difficult. Without estimates of discharge, the impacts of contaminated discharge on surface streams would be difficult to evaluate. An approach to obtaining an estimate was developed using the Environmental Protection Agency (EPA) Cornell Mixing Zone Expert System (CORMIX). The thermography was queried to obtain a temperature profile down the center of the surface plume. The spring discharge was modeled with CORMIX, and the flow adjusted until the surface temperature profile was matched. The presence of volatile compounds in some of the new springs also allowed MSFC to unravel the natural system of solution cavities of the karst aquifer. Sampling results also showed that two springs on either side of a large creek had the same water source so that groundwater was able to pass beneath the creek.

  5. A relative-intensity two-color phosphor thermography system

    NASA Technical Reports Server (NTRS)

    Merski, N. Ronald

    1991-01-01

    The NASA LaRC has developed a relative-intensity two-color phosphor thermography system. This system has become a standard technique for acquiring aerothermodynamic data in LaRC Hypersonic Facilities Complex (HFC). The relative intensity theory and its application to the LaRC phosphor thermography system is discussed along with the investment casting technique which is critical to the utilization of the phosphor method for aerothermodynamic studies. Various approaches to obtaining quantitative heat transfer data using thermographic phosphors are addressed and comparisons between thin-film data and thermographic phosphor data on an orbiter-like configuration are presented. In general, data from these two techniques are in good agreement. A discussion is given on the application of phosphors to integration heat transfer data reduction techniques (the thin film method) and preliminary heat transfer data obtained on a calibration sphere using thin-film equations are presented. Finally, plans for a new phosphor system which uses target recognition software are discussed.

  6. Computed Tomography and Thermography Increases CMC Material and Process Development Efficiency and Testing Effectiveness

    NASA Technical Reports Server (NTRS)

    Effinger, Michael; Beshears, Ron; Hufnagle, David; Walker, James; Russell, Sam; Stowell, Bob; Myers, David

    2002-01-01

    Nondestructive characterization techniques have been used to steer development and testing of CMCs. Computed tomography is used to determine the volumetric integrity of the CMC plates and components. Thermography is used to determine the near surface integrity of the CMC plates and components. For process and material development, information such as density uniformity, part delamination, and dimensional tolerance conformity is generated. The information from the thermography and computed tomography is correlated and then specimen cutting maps are superimposed on the thermography images. This enables for tighter data and potential explanation of off nominal test data. Examples of nondestructive characterization utilization to make decisions in process and material development and testing are presented.

  7. Musical Acoustics

    NASA Astrophysics Data System (ADS)

    Gough, Colin

    This chapter provides an introduction to the physical and psycho-acoustic principles underlying the production and perception of the sounds of musical instruments. The first section introduces generic aspects of musical acoustics and the perception of musical sounds, followed by separate sections on string, wind and percussion instruments.

  8. Acoustic metafluids.

    PubMed

    Norris, Andrew N

    2009-02-01

    Acoustic metafluids are defined as the class of fluids that allow one domain of fluid to acoustically mimic another, as exemplified by acoustic cloaks. It is shown that the most general class of acoustic metafluids are materials with anisotropic inertia and the elastic properties of what are known as pentamode materials. The derivation uses the notion of finite deformation to define the transformation of one region to another. The main result is found by considering energy density in the original and transformed regions. Properties of acoustic metafluids are discussed, and general conditions are found which ensure that the mapped fluid has isotropic inertia, which potentially opens up the possibility of achieving broadband cloaking. PMID:19206861

  9. Infrared thermography for laser-based powder bed fusion additive manufacturing processes

    NASA Astrophysics Data System (ADS)

    Moylan, Shawn; Whitenton, Eric; Lane, Brandon; Slotwinski, John

    2014-02-01

    Additive manufacturing (AM) has the potential to revolutionize discrete part manufacturing, but improvements in processing of metallic materials are necessary before AM will see widespread adoption. A better understanding of AM processes, resulting from physics-based modeling as well as direct process metrology, will form the basis for these improvements. Infrared (IR) thermography of AM processes can provide direct process metrology, as well as data necessary for the verification of physics-based models. We review selected works examining how IR thermography was implemented and used in various powder-bed AM processes. This previous work, as well as significant experience at the National Institute of Standards and Technology in temperature measurement and IR thermography for machining processes, shapes our own research in AM process metrology with IR thermography. We discuss our experimental design, as well as plans for future IR measurements of a laser-based powder bed fusion AM process.

  10. Infrared thermography for laser-based powder bed fusion additive manufacturing processes

    SciTech Connect

    Moylan, Shawn; Whitenton, Eric; Lane, Brandon; Slotwinski, John

    2014-02-18

    Additive manufacturing (AM) has the potential to revolutionize discrete part manufacturing, but improvements in processing of metallic materials are necessary before AM will see widespread adoption. A better understanding of AM processes, resulting from physics-based modeling as well as direct process metrology, will form the basis for these improvements. Infrared (IR) thermography of AM processes can provide direct process metrology, as well as data necessary for the verification of physics-based models. We review selected works examining how IR thermography was implemented and used in various powder-bed AM processes. This previous work, as well as significant experience at the National Institute of Standards and Technology in temperature measurement and IR thermography for machining processes, shapes our own research in AM process metrology with IR thermography. We discuss our experimental design, as well as plans for future IR measurements of a laser-based powder bed fusion AM process.

  11. A comparative review of thermography as a breast cancer screening technique.

    PubMed

    Kennedy, Deborah A; Lee, Tanya; Seely, Dugald

    2009-03-01

    Breast cancer is the most frequently diagnosed cancer of women in North America. Despite advances in treatment that have reduced mortality, breast cancer remains the second leading cause of cancer induced death. Several well established tools are used to screen for breast cancer including clinical breast exams, mammograms, and ultrasound. Thermography was first introduced as a screening tool in 1956 and was initially well accepted. However, after a 1977 study found thermography to lag behind other screening tools, the medical community lost interest in this diagnostic approach. This review discusses each screening tool with a focus brought to thermography. No single tool provides excellent predictability; however, a combination that incorporates thermography may boost both sensitivity and specificity. In light of technological advances and maturation of the thermographic industry, additional research is required to confirm the potential of this technology to provide an effective non-invasive, low risk adjunctive tool for the early detection of breast cancer.

  12. Subsurface defect detection in first layer of pavement structure and reinforced civil engineering structure by FRP bonding using active infrared thermography

    NASA Astrophysics Data System (ADS)

    Dumoulin, Jean; Ibos, Laurent

    2010-05-01

    In many countries road network ages while road traffic and maintenance costs increase. Nowadays, thousand and thousand kilometers of roads are each year submitted to surface distress survey. They generally lean on pavement surface imaging measurement techniques, mainly in the visible spectrum, coupled with visual inspection or image processing detection of emergent distresses. Nevertheless, optimisation of maintenance works and costs requires an early detection of defects within the pavement structure when they still are hidden from surface. Accordingly, alternative measurement techniques for pavement monitoring are currently under investigation (seismic methods, step frequency radar). On the other hand, strengthening or retrofitting of reinforced concrete structures by externally bonded Fiber Reinforced Polymer (FRP) systems is now a commonly accepted and widespread technique. However, the use of bonding techniques always implies following rigorous installing procedures. To ensure the durability and long-term performance of the FRP reinforcements, conformance checking through an in situ auscultation of the bonded FRP systems is then highly suitable. The quality-control program should involve a set of adequate inspections and tests. Visual inspection and acoustic sounding (hammer tap) are commonly used to detect delaminations (disbonds) but are unable to provide sufficient information about the depth (in case of multilayered composite) and width of debonded areas. Consequently, rapid and efficient inspection methods are also required. Among the non destructive methods under study, active infrared thermography was investigated both for pavement and civil engineering structures through experiments in laboratory and numerical simulations, because of its ability to be also used on field. Pulse Thermography (PT), Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) approaches have been tested onto pavement samples and CFRP bonding on concrete

  13. Potentialities of steady-state and transient thermography in breast tumour depth detection: A numerical study.

    PubMed

    Amri, Amina; Pulko, Susan Helen; Wilkinson, Anthony James

    2016-01-01

    Breast thermography still has inherent limitations that prevent it from being fully accepted as a breast screening modality in medicine. The main challenges of breast thermography are to reduce false positive results and to increase the sensitivity of a thermogram. Further, it is still difficult to obtain information about tumour parameters such as metabolic heat, tumour depth and diameter from a thermogram. However, infrared technology and image processing have advanced significantly and recent clinical studies have shown increased sensitivity of thermography in cancer diagnosis. The aim of this paper is to study numerically the possibilities of extracting information about the tumour depth from steady state thermography and transient thermography after cold stress with no need to use any specific inversion technique. Both methods are based on the numerical solution of Pennes bioheat equation for a simple three-dimensional breast model. The effectiveness of two approaches used for depth detection from steady state thermography is assessed. The effect of breast density on the steady state thermal contrast has also been studied. The use of a cold stress test and the recording of transient contrasts during rewarming were found to be potentially suitable for tumour depth detection during the rewarming process. Sensitivity to parameters such as cold stress temperature and cooling time is investigated using the numerical model and simulation results reveal two prominent depth-related characteristic times which do not strongly depend on the temperature of the cold stress or on the cooling period.

  14. Potentialities of steady-state and transient thermography in breast tumour depth detection: A numerical study.

    PubMed

    Amri, Amina; Pulko, Susan Helen; Wilkinson, Anthony James

    2016-01-01

    Breast thermography still has inherent limitations that prevent it from being fully accepted as a breast screening modality in medicine. The main challenges of breast thermography are to reduce false positive results and to increase the sensitivity of a thermogram. Further, it is still difficult to obtain information about tumour parameters such as metabolic heat, tumour depth and diameter from a thermogram. However, infrared technology and image processing have advanced significantly and recent clinical studies have shown increased sensitivity of thermography in cancer diagnosis. The aim of this paper is to study numerically the possibilities of extracting information about the tumour depth from steady state thermography and transient thermography after cold stress with no need to use any specific inversion technique. Both methods are based on the numerical solution of Pennes bioheat equation for a simple three-dimensional breast model. The effectiveness of two approaches used for depth detection from steady state thermography is assessed. The effect of breast density on the steady state thermal contrast has also been studied. The use of a cold stress test and the recording of transient contrasts during rewarming were found to be potentially suitable for tumour depth detection during the rewarming process. Sensitivity to parameters such as cold stress temperature and cooling time is investigated using the numerical model and simulation results reveal two prominent depth-related characteristic times which do not strongly depend on the temperature of the cold stress or on the cooling period. PMID:26522612

  15. Porosity Measurement in Laminated Composites by Thermography and FEA

    NASA Technical Reports Server (NTRS)

    Chu, Tsuchin Philip; Russell, Samuel S.; Walker, James L.; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    This paper presents the correlation between the through-thickness thermal diffusivity and the porosity of composites. Finite element analysis (FEA) was used to determine the transient thermal response of composites that were subjected to laser heating. A series of finite element models were built and thermal responses for isotropic and orthographic materials with various thermal diffusivities subjected to different heating conditions were investigated. Experiments were conducted to verify the models and to estimate the unknown parameters such as the amount of heat flux. The analysis and experimental results show good correlation between thermal diffusivity and porosity in the composite materials. They also show that both laser and flash heating can be used effectively to obtain thermal diffusivity. The current infrared thermography system is developed for use with flash heating. The laser heating models and the FEA results can provide useful tools to develop practical thermal diffusivity measurement scheme using laser heat.

  16. Eddy current pulsed thermography for fatigue evaluation of gear

    NASA Astrophysics Data System (ADS)

    Tian, Gui Yun; Yin, Aijun; Gao, Bin; Zhang, Jishan; Shaw, Brian

    2014-02-01

    The pulsed eddy current (PEC) technique generates responses over a wide range of frequencies, containing more spectral coverage than traditional eddy current inspection. Eddy current pulsed thermography (ECPT), a newly developed non-destructive testing (NDT) technique, has advantages such as rapid inspection of a large area within a short time, high spatial resolution, high sensitivity and stand-off measurement distance. This paper investigates ECPT for the evaluation of gear fatigue tests. The paper proposes a statistical method based on single channel blind source separation to extract details of gear fatigue. The discussion of transient thermal distribution and patterns of fatigue contact surfaces as well as the non-contact surfaces have been reported. In addition, the measurement for gears with different cycles of fatigue tests by ECPTand the comparison results between ECPT with magnetic Barkhausen noise (MBN) have been evaluated. The comparison shows the competitive capability of ECPT in fatigue evaluation.

  17. Modeling of the Multiparameter Inverse Task of Transient Thermography

    NASA Technical Reports Server (NTRS)

    Plotnikov, Y. A.

    1998-01-01

    Transient thermography employs preheated surface temperature variations caused by delaminations, cracks, voids, corroded regions, etc. Often, it is enough to detect these changes to declare a defect in a workpiece. It is also desirable to obtain additional information about the defect from the thermal response. The planar size, depth, and thermal resistance of the detected defects are the parameters of interest. In this paper a digital image processing technique is applied to simulated thermal responses in order to obtain the geometry of the inclusion-type defects in a flat panel. A three-dimensional finite difference model in Cartesian coordinates is used for the numerical simulations. Typical physical properties of polymer graphite composites are assumed. Using different informative parameters of the thermal response for depth estimation is discussed.

  18. Real time capable infrared thermography for ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Sieglin, B.; Faitsch, M.; Herrmann, A.; Brucker, B.; Eich, T.; Kammerloher, L.; Martinov, S.

    2015-11-01

    Infrared (IR) thermography is widely used in fusion research to study power exhaust and incident heat load onto the plasma facing components. Due to the short pulse duration of today's fusion experiments, IR systems have mostly been designed for off-line data analysis. For future long pulse devices (e.g., Wendelstein 7-X, ITER), a real time evaluation of the target temperature and heat flux is mandatory. This paper shows the development of a real time capable IR system for ASDEX Upgrade. A compact IR camera has been designed incorporating the necessary magnetic and electric shielding for the detector, cooler assembly. The camera communication is based on the Camera Link industry standard. The data acquisition hardware is based on National Instruments hardware, consisting of a PXIe chassis inside and a fibre optical connected industry computer outside the torus hall. Image processing and data evaluation are performed using real time LabVIEW.

  19. Real time capable infrared thermography for ASDEX Upgrade.

    PubMed

    Sieglin, B; Faitsch, M; Herrmann, A; Brucker, B; Eich, T; Kammerloher, L; Martinov, S

    2015-11-01

    Infrared (IR) thermography is widely used in fusion research to study power exhaust and incident heat load onto the plasma facing components. Due to the short pulse duration of today's fusion experiments, IR systems have mostly been designed for off-line data analysis. For future long pulse devices (e.g., Wendelstein 7-X, ITER), a real time evaluation of the target temperature and heat flux is mandatory. This paper shows the development of a real time capable IR system for ASDEX Upgrade. A compact IR camera has been designed incorporating the necessary magnetic and electric shielding for the detector, cooler assembly. The camera communication is based on the Camera Link industry standard. The data acquisition hardware is based on National Instruments hardware, consisting of a PXIe chassis inside and a fibre optical connected industry computer outside the torus hall. Image processing and data evaluation are performed using real time LabVIEW.

  20. Aerial thermography studies of power plant heated lakes

    SciTech Connect

    Villa-Aleman, E.

    2000-01-26

    Remote sensing temperature measurements of water bodies is complicated by the temperature differences between the true surface or skin water and the bulk water below. Weather conditions control the reduction of the skin temperature relative to the bulk water temperature. Typical skin temperature depressions range from a few tenths of a degree Celsius to more than one degree. In this research project, the Savannah River Technology Center (SRTC) used aerial thermography and surface-based meteorological and water temperature measurements to study a power plant cooling lake in South Carolina. Skin and bulk water temperatures were measured simultaneously for imagery calibration and to produce a database for modeling of skin temperature depressions as a function of weather and bulk water temperatures. This paper will present imagery that illustrates how the skin temperature depression was affected by different conditions in several locations on the lake and will present skin temperature modeling results.

  1. Infrared-thermography imaging system multiapplications for manufacturing

    NASA Astrophysics Data System (ADS)

    Stern, Sharon A.

    1990-03-01

    Imaging systems technology has been utilized traditionally for diagnosing structural envelope or insulation problems in the general thermographic comunity. Industrially, new applications for utilizing thermal imaging technology have been developed i n pred i cti ve/preventi ye mai ntenance and prod uct moni tori ng prociures at Eastman Kodak Company, the largest photographic manufacturering producer in the world. In the manufacturing processes used at Eastman Kodak Company, new applications for thermal imaging include: (1) Fluid transfer line insulation (2) Web coating drying uniformity (3) Web slitter knives (4) Heating/cooling coils (5) Overheated tail bearings, and (6) Electrical phase imbalance. The substantial cost benefits gained from these applications of infrared thermography substantiate the practicality of this approach and indicate the desirability of researching further appl i cati ons.

  2. Optimized laser application in dermatology using infrared thermography

    NASA Astrophysics Data System (ADS)

    Thomas, Roderick A.; Donne, Kelvin E.; Clement, Marc; Kiernan, Michael N.

    2002-03-01

    Infrared thermography can be used to optimize the application of lasers in dermatology with particular reference to the treatment of certain skin disorders such as vascular lesions and depilation. The efficacy of treatment is dependent upon a number of factors including: Optimization and correct selection of laser parameters such as wavelength and spot size. Human factors, such as laser operator skill, patient's skin type and anatomical location. By observing the thermal effects of laser irradiation on the skins surface during treatment results in improved efficacy and minimizes the possible threshold to skin damage, reducing the possibility of burning and scarring. This is of particular significance for example, in the control of purpura for the treatment of vascular lesions. The optimization is validated with reference to a computer model that predicts various skin temperatures based on two different laser spot sizes.

  3. Technical design note: differential infrared thermography of methane jets

    NASA Astrophysics Data System (ADS)

    Golzke, Hendrik; Leick, Philippe; Dreizler, Andreas

    2016-10-01

    In this note a novel approach for temperature measurements of methane jets is presented. Differential infrared thermography (DIT) is a contactless, tracer-free temperature determination method for semi-transparent objects, based on an infrared camera. DIT does not rely on a specific a priori value for the emissivity, but typically assumes constant emissivity within the relevant wavelength band. This is reasonable for complex hydrocarbons (i.e. as in liquid fuel sprays) but no longer justified for the discrete absorption spectrum of simple molecules such as methane. An alternative approximation is suggested and discussed, and the feasibility of DIT for the study of supercritical methane jets in a pressure chamber at conditions relevant for internal combustion engines is demonstrated. As DIT also determines the gas emissivity, a combined two-dimensional temperature and projected density visualisation becomes possible and is shown to highlight supersonic structurues such as Mach disks.

  4. Localization of wood floor structure by infrared thermography

    NASA Astrophysics Data System (ADS)

    Cochior Plescanu, C.; Klein, M.; Ibarra-Castanedo, C.; Bendada, A.; Maldague, X.

    2008-03-01

    One of our industrial partners, Assek Technologie, is interested in developing a technique that would improve the drying process of wood floor in basements after flooding. In order to optimize the procedure, the floor structure and the damaged (wet) area extent must first be determined with minimum intrusion (minimum or no dismantling). The present study presents the use of infrared thermography to reveal the structure of (flooded) wood floors. The procedure involves opening holes in the floor. Injecting some hot air through those holes reveals the framing structure even if the floor is covered by vinyl or ceramic tiles. This study indicates that thermal imaging can also be used as a tool to validate the decontamination process after drying. Thermal images were obtained on small-scale models and in a demonstration room.

  5. High speed heterodyne infrared thermography applied to thermal diffusivity identification.

    PubMed

    Pradere, C; Clerjaud, L; Batsale, J C; Dilhaire, S

    2011-05-01

    We have combined InfraRed thermography and thermal wave techniques to perform microscale, ultrafast (microsecond) temperature field measurements. The method is based on an IR camera coupled to a microscope and synchronized to the heat source by means of phase locked function generators. The principle is based on electronic stroboscopic sampling where the low IR camera acquisition frequency f(acq) (25 Hz) undersamples a high frequency thermal wave. This technique permits the measurement of the emissive thermal response at a (microsecond) short time scale (microsecond) with the full frame mode of the IR camera with a spatial thermal resolution of 7 μm. Then it becomes possible to study 3D transient heat transfer in heterogeneous and high thermal conductive thin layers. Thus it is possible for the first time in our knowledge to achieve temperature field measurements in heterogeneous media within a wide range of time domains. The IR camera is now a suitable instrument for multiscale thermal analysis.

  6. Advanced Image Processing for Defect Visualization in Infrared Thermography

    NASA Technical Reports Server (NTRS)

    Plotnikov, Yuri A.; Winfree, William P.

    1997-01-01

    Results of a defect visualization process based on pulse infrared thermography are presented. Algorithms have been developed to reduce the amount of operator participation required in the process of interpreting thermographic images. The algorithms determine the defect's depth and size from the temporal and spatial thermal distributions that exist on the surface of the investigated object following thermal excitation. A comparison of the results from thermal contrast, time derivative, and phase analysis methods for defect visualization are presented. These comparisons are based on three dimensional simulations of a test case representing a plate with multiple delaminations. Comparisons are also based on experimental data obtained from a specimen with flat bottom holes and a composite panel with delaminations.

  7. Detection of pathogenic gram negative bacteria using infrared thermography

    NASA Astrophysics Data System (ADS)

    Lahiri, B. B.; Divya, M. P.; Bagavathiappan, S.; Thomas, Sabu; Philip, John

    2012-11-01

    Detection of viable bacteria is of prime importance in all fields of microbiology and biotechnology. Conventional methods of enumerating bacteria are often time consuming and labor-intensive. All living organisms generate heat due to metabolic activities and hence, measurement of heat energy is a viable tool for detection and quantification of bacteria. In this article, we employ a non-contact and real time method - infrared thermography (IRT) for measurement of temperature variations in four clinically significant gram negative pathogenic bacteria, viz. Vibrio cholerae, Vibrio mimicus, Proteus mirabilis and Pseudomonas aeruginosa. We observe that, the energy content, defined as the ratio of heat generated by bacterial metabolic activities to the heat lost from the liquid medium to the surrounding, vary linearly with the bacterial concentration in all the four pathogenic bacteria. The amount of energy content observed in different species is attributed to their metabolisms and morphologies that affect the convection velocity and hence heat transport in the medium.

  8. IR-thermography for Quality Prediction in Selective Laser Deburring

    NASA Astrophysics Data System (ADS)

    Möller, Mauritz; Conrad, Christian; Haimerl, Walter; Emmelmann, Claus

    Selective Laser Deburring (SLD) is an innovative edge-refinement process being developed at the Laser Zentrum Nord (LZN) in Hamburg. It offers a wear-free processing of defined radii and bevels at the edges as well as the possibility to deburr several materials with the same laser source. Sheet metal parts of various applications need to be post-processed to remove sharp edges and burrs remaining from the initial production process. Thus, SLD will provide an extended degree of automation for the next generation of manufacturing facilities. This paper investigates the dependence between the deburring result and the temperature field in- and post-process. In order to achieve this, the surface temperature near to the deburred edge is monitored with IR-thermography. Different strategies are discussed for the approach using the IR-information as a quality assurance. Additional experiments are performed to rate the accuracy of the quality prediction method in different deburring applications.

  9. IR thermography for dynamic detection of laminar-turbulent transition

    NASA Astrophysics Data System (ADS)

    Simon, Bernhard; Filius, Adrian; Tropea, Cameron; Grundmann, Sven

    2016-05-01

    This work investigates the potential of infrared (IR) thermography for the dynamic detection of laminar-turbulent transition. The experiments are conducted on a flat plate at velocities of 8-14 m/s, and the transition of the laminar boundary layer to turbulence is forced by a disturbance source which is turned on and off with frequencies up to 10 Hz. Three different heating techniques are used to apply the required difference between fluid and structure temperature: a heated aluminum structure is used as an internal structure heating technique, a conductive paint acts as a surface bounded heater, while an IR heater serves as an example for an external heating technique. For comparison of all heating techniques, a normalization is introduced and the frequency response of the measured IR camera signal is analyzed. Finally, the different heating techniques are compared and consequences for the design of experiments on laminar-turbulent transition are discussed.

  10. Real time capable infrared thermography for ASDEX Upgrade

    SciTech Connect

    Sieglin, B. Faitsch, M.; Herrmann, A.; Brucker, B.; Eich, T.; Kammerloher, L.; Martinov, S.

    2015-11-15

    Infrared (IR) thermography is widely used in fusion research to study power exhaust and incident heat load onto the plasma facing components. Due to the short pulse duration of today’s fusion experiments, IR systems have mostly been designed for off-line data analysis. For future long pulse devices (e.g., Wendelstein 7-X, ITER), a real time evaluation of the target temperature and heat flux is mandatory. This paper shows the development of a real time capable IR system for ASDEX Upgrade. A compact IR camera has been designed incorporating the necessary magnetic and electric shielding for the detector, cooler assembly. The camera communication is based on the Camera Link industry standard. The data acquisition hardware is based on National Instruments hardware, consisting of a PXIe chassis inside and a fibre optical connected industry computer outside the torus hall. Image processing and data evaluation are performed using real time LabVIEW.

  11. HeatWave: the next generation of thermography devices

    NASA Astrophysics Data System (ADS)

    Moghadam, Peyman; Vidas, Stephen

    2014-05-01

    Energy sustainability is a major challenge of the 21st century. To reduce environmental impact, changes are required not only on the supply side of the energy chain by introducing renewable energy sources, but also on the demand side by reducing energy usage and improving energy efficiency. Currently, 2D thermal imaging is used for energy auditing, which measures the thermal radiation from the surfaces of objects and represents it as a set of color-mapped images that can be analysed for the purpose of energy efficiency monitoring. A limitation of such a method for energy auditing is that it lacks information on the geometry and location of objects with reference to each other, particularly across separate images. Such a limitation prevents any quantitative analysis to be done, for example, detecting any energy performance changes before and after retrofitting. To address these limitations, we have developed a next generation thermography device called Heat Wave. Heat Wave is a hand-held 3D thermography device that consists of a thermal camera, a range sensor and color camera, and can be used to generate precise 3D model of objects with augmented temperature and visible information. As an operator holding the device smoothly waves it around the objects of interest, Heat Wave can continuously track its own pose in space and integrate new information from the range and thermal and color cameras into a single, and precise 3D multi-modal model. Information from multiple viewpoints can be incorporated together to improve the accuracy, reliability and robustness of the global model. The approach also makes it possible to reduce any systematic errors associated with the estimation of surface temperature from the thermal images.

  12. Dual-band infrared thermography for quantitative nondestructive evaluation

    SciTech Connect

    Durbin, P.F.; Del Grande, N.K.; Dolan, K.W.; Perkins, D.E.; Shapiro, A.B.

    1993-04-01

    The authors have developed dual-band infrared (DBIR) thermography that is being applied to quantitative nondestructive evaluation (NDE) of aging aircraft. The DBIR technique resolves 0.2 degrees C surface temperature differences for inspecting interior flaws in heated aircraft structures. It locates cracks, corrosion sites, disbonds or delaminations in metallic laps and composite patches. By removing clutter from surface roughness effects, the authors clarify interpretation of subsurface flaws. To accomplish this, the authors ratio images recorded at two infrared bands, centered near 5 microns and 10 microns. These image ratios are used to decouple temperature patterns associated with interior flaw sites from spatially varying surface emissivity noise. They also discuss three-dimensional (3D) dynamic thermal imaging of structural flaws using dual-band infrared (DBIR) computed tomography. Conventional thermography provides single-band infrared images which are difficult to interpret. Standard procedures yield imprecise (or qualitative) information about subsurface flaw sites which are typically masked by surface clutter. They use a DBIR imaging technique pioneered at LLNL to capture the time history of surface temperature difference patterns for flash-heated targets. They relate these patterns to the location, size, shape and depth of subsurface flaws. They have demonstrated temperature accuracies of 0.2{degree}C, timing synchronization of 3 ms (after onset of heat flash) and intervals of 42 ms, between images, during an 8 s cooling (and heating) interval characterizing the front (and back) surface temperature-time history of an epoxy-glue disbond site in a flash-heated aluminum lap joint.

  13. Application of infrared thermography in computer aided diagnosis

    NASA Astrophysics Data System (ADS)

    Faust, Oliver; Rajendra Acharya, U.; Ng, E. Y. K.; Hong, Tan Jen; Yu, Wenwei

    2014-09-01

    The invention of thermography, in the 1950s, posed a formidable problem to the research community: What is the relationship between disease and heat radiation captured with Infrared (IR) cameras? The research community responded with a continuous effort to find this crucial relationship. This effort was aided by advances in processing techniques, improved sensitivity and spatial resolution of thermal sensors. However, despite this progress fundamental issues with this imaging modality still remain. The main problem is that the link between disease and heat radiation is complex and in many cases even non-linear. Furthermore, the change in heat radiation as well as the change in radiation pattern, which indicate disease, is minute. On a technical level, this poses high requirements on image capturing and processing. On a more abstract level, these problems lead to inter-observer variability and on an even more abstract level they lead to a lack of trust in this imaging modality. In this review, we adopt the position that these problems can only be solved through a strict application of scientific principles and objective performance assessment. Computing machinery is inherently objective; this helps us to apply scientific principles in a transparent way and to assess the performance results. As a consequence, we aim to promote thermography based Computer-Aided Diagnosis (CAD) systems. Another benefit of CAD systems comes from the fact that the diagnostic accuracy is linked to the capability of the computing machinery and, in general, computers become ever more potent. We predict that a pervasive application of computers and networking technology in medicine will help us to overcome the shortcomings of any single imaging modality and this will pave the way for integrated health care systems which maximize the quality of patient care.

  14. Acoustic trauma

    MedlinePlus

    Acoustic trauma is a common cause of sensory hearing loss . Damage to the hearing mechanisms within the inner ... Symptoms include: Partial hearing loss that most often involves ... The hearing loss may slowly get worse. Noises, ringing in ...

  15. Acoustic Neuroma

    MedlinePlus

    ... slow growing tumor which arise primarily from the vestibular portion of the VIII cranial nerve and lie ... you have a "brain tumor" called acoustic neuroma (vestibular schwannoma). You think you are the only one ...

  16. Underwater Acoustics.

    ERIC Educational Resources Information Center

    Creasey, D. J.

    1981-01-01

    Summarizes the history of underwater acoustics and describes related research studies and teaching activities at the University of Birmingham (England). Also includes research studies on transducer design and mathematical techniques. (SK)

  17. Room Acoustics

    NASA Astrophysics Data System (ADS)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  18. Acoustic biosensors

    PubMed Central

    Fogel, Ronen; Seshia, Ashwin A.

    2016-01-01

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  19. Acoustic biosensors.

    PubMed

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

    2016-06-30

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  20. Tracking composite material damage evolution using Bayesian filtering and flash thermography data

    NASA Astrophysics Data System (ADS)

    Gregory, Elizabeth D.; Holland, Steve D.

    2016-05-01

    We propose a method for tracking the condition of a composite part using Bayesian filtering of ash thermography data over the lifetime of the part. In this demonstration, composite panels were fabricated; impacted to induce subsurface delaminations; and loaded in compression over multiple time steps, causing the delaminations to grow in size. Flash thermography data was collected between each damage event to serve as a time history of the part. The ash thermography indicated some areas of damage but provided little additional information as to the exact nature or depth of the damage. Computed tomography (CT) data was also collected after each damage event and provided a high resolution volume model of damage that acted as truth. After each cycle, the condition estimate, from the ash thermography data and the Bayesian filter, was compared to 'ground truth'. The Bayesian process builds on the lifetime history of ash thermography scans and can give better estimates of material condition as compared to the most recent scan alone, which is common practice in the aerospace industry. Bayesian inference provides probabilistic estimates of damage condition that are updated as each new set of data becomes available. The method was tested on simulated data and then on an experimental data set.

  1. Physical interpretation and separation of eddy current pulsed thermography

    NASA Astrophysics Data System (ADS)

    Yin, Aijun; Gao, Bin; Yun Tian, Gui; Woo, W. L.; Li, Kongjing

    2013-02-01

    Eddy current pulsed thermography (ECPT) applies induction heating and a thermal camera for non-destructive testing and evaluation (NDT&E). Because of the variation in resultant surface heat distribution, the physical mechanism that corresponds to the general behavior of ECPT can be divided into an accumulation of Joule heating via eddy current and heat diffusion. However, throughout the literature, the heating mechanisms of ECPT are not given in detail in the above two thermal phenomena and they are difficult to be separated. Nevertheless, once these two physical parameters are separated, they can be directly used to detect anomalies and predict the variation in material properties such as electrical conductivity, magnetic permeability and microstructure. This paper reports physical interpretation of these two physical phenomena that can be found in different time responses given the ECPT image sequences. Based on the phenomenon and their behaviors, the paper proposes a statistical method based on single channel blind source separation to decompose the two physical phenomena using different stages of eddy current and thermal propagation from the ECPT images. Links between mathematical models and physical models have been discussed and verified. This fundamental understanding of transient eddy current distribution and heating propagation can be applied to the development of feature extraction and pattern recognition for the quantitative analysis of ECPT measurement images and defect characterization.

  2. Measuring and Estimating Normalized Contrast in Infrared Flash Thermography

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay M.

    2013-01-01

    Infrared flash thermography (IRFT) is used to detect void-like flaws in a test object. The IRFT technique involves heating up the part surface using a flash of flash lamps. The post-flash evolution of the part surface temperature is sensed by an IR camera in terms of pixel intensity of image pixels. The IR technique involves recording of the IR video image data and analysis of the data using the normalized pixel intensity and temperature contrast analysis method for characterization of void-like flaws for depth and width. This work introduces a new definition of the normalized IR pixel intensity contrast and normalized surface temperature contrast. A procedure is provided to compute the pixel intensity contrast from the camera pixel intensity evolution data. The pixel intensity contrast and the corresponding surface temperature contrast differ but are related. This work provides a method to estimate the temperature evolution and the normalized temperature contrast from the measured pixel intensity evolution data and some additional measurements during data acquisition.

  3. Monitoring sintering burn-through point using infrared thermography.

    PubMed

    Usamentiaga, Rubén; Molleda, Julio; Garcia, Daniel F; Bulnes, Francisco G

    2013-01-01

    Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process. PMID:23939585

  4. The Effects of Heating Methods on Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Mercer, A. Scott; Klinkhachorn, P.; Halabe, Udaya B.; GangaRao, Hota V. S.

    2007-03-01

    Infrared (IR) Thermography is a good way of detecting air filled defects in FRP decks. When heat is applied to the deck surface, the material over the air void heats up faster and becomes hotter than the surrounding area and an IR camera can distinguish this defective area from a sound area in the deck based on surface temperature measurements. Since this technique requires application of heat in order to produce results, it seems only logical that one should research the effects of different heating types on the defect analysis. For this study, various heat sources; such as the sun, a 5000 BTU quartz electric heater, a 9000 BTU propane convection heater, and a 35000 BTU forced air propane heater, were used to heat up an FRP deck specimen with built-in defects for IR analysis. Different heating times were used to determine the effects on the accuracy and the total elapsed time involved in seeing a defect in the resultant IR images. A few methods, such as CO2 cooling, for decreasing the time it takes to see the defect in the image were also explored.

  5. Monitoring sintering burn-through point using infrared thermography.

    PubMed

    Usamentiaga, Rubén; Molleda, Julio; Garcia, Daniel F; Bulnes, Francisco G

    2013-08-09

    Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process.

  6. Monitoring Sintering Burn-Through Point Using Infrared Thermography

    PubMed Central

    Usamentiaga, Rubén; Molleda, Julio; Garcia, Daniel F.; Bulnes, Francisco G.

    2013-01-01

    Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process. PMID:23939585

  7. Assessment of lower limb prosthesis through wearable sensors and thermography.

    PubMed

    Cutti, Andrea Giovanni; Perego, Paolo; Fusca, Marcello C; Sacchetti, Rinaldo; Andreoni, Giuseppe

    2014-03-11

    This study aimed to explore the application of infrared thermography in combination with ambulatory wearable monitoring of temperature and relative humidity, to assess the residual limb-to-liner interface in lower-limb prosthesis users. Five male traumatic transtibial amputees were involved, who reported no problems or discomfort while wearing the prosthesis. A thermal imaging camera was used to measure superficial thermal distribution maps of the stump. A wearable system for recording the temperature and relative humidity in up to four anatomical points was developed, tested in vitro and integrated with the measurement set. The parallel application of an infrared camera and wearable sensors provided complementary information. Four main Regions of Interest were identified on the stump (inferior patella, lateral/medial epicondyles, tibial tuberosity), with good inter-subject repeatability. An average increase of 20% in hot areas (P < 0.05) is shown after walking compared to resting conditions. The sensors inside the cuff did not provoke any discomfort during recordings and provide an inside of the thermal exchanges while walking and recording the temperature increase (a regime value is ~+1.1 ± 0.7 °C) and a more significant one (~+4.1 ± 2.3%) in humidity because of the sweat produced. This study has also begun the development of a reference data set for optimal socket/liner-stump construction.

  8. Surface temperatures of insulated glazing units: Infrared thermography laboratory measurements

    SciTech Connect

    Griffith, B.T.; Tuerler, D.; Arasteh, D.

    1995-12-01

    Data are presented for the distribution of surface temperatures on the warm-side surface of seven different insulated glazing units. Surface temperatures are measured using infrared thermography and an external referencing technique. This technique allows detailed mapping of surface temperatures that is non-intrusive. The glazings were placed between warm and cold environmental chambers that were operated at conditions corresponding to standard design conditions for winter heating. The temperatures conditions are 2 1.1{degrees}C (70{degrees}F) and -17.8{degrees}C (0{degrees}F) on the warm and cold sides, respectively. Film coefficients varied somewhat with average conditions of about 7.6 W/m{sup 2}{circ}K (1.34 Btu/h-ft{sup 2}{circ}{degrees}F) for the warm-side and 28.9 W/m{sup 2}{circ}K (5.1 Btu/h{circ}ft{sup 2}{circ}{degrees}F) for the cold-side. Surface temperature data are plotted for the vertical distribution along the centerline of the IG and for the horizontal distribution along the centerline. This paper is part of larger collaborative effort that studied the same set of glazings.

  9. Use of modern infrared thermography for wildlife population surveys

    NASA Astrophysics Data System (ADS)

    Garner, Dale L.; Underwood, H. Brian; Porter, William F.

    1995-03-01

    A commercially available thermal-infrared scanning system was used to survey populations of several wildlife species. The system's ability to detect species of different sizes in varying habitats relative to conventional survey methods, to differentiate between species in the same habitat, and the influence of environtmental factors on operational aspects of employing this technology in the field were evaluated. Total costs for the surveys were approximately 0.36/ha. There were marked discrepancies in the counts of untrained observers and those from trained analysis. Computer-assisted analysis of infrared imagery recorded 52% fewer deer than were estimated from drive counts, and densities of moose were five times those estimated from conventional aerial methods. By flying concentric circles and using telephoto, detailed counts of turkeys and deer were possible. With the aid of computer-assisted analysis, infrared thermography may become a useful wildlife population survey tool. More research is needed to verify the actual efficiency of detection by combining aerial scans with ground truthing for a variely of species and habitals.

  10. Nondestructive evaluation of weld defects by infrared thermography

    SciTech Connect

    Satonaka, Shinobu; Ohba, Hiroyasu; Shinozaki, Kenya

    1995-12-31

    In order to clarify the applicability of infrared thermography to the nondestructive evaluation of weld defects, an infrared measurement was conducted on the welds with various artificial defects. Two heating methods, a moving gas flame and a Joule effect by electric current flow, were used for the fast and large area inspection with readily interpretable images of defects. Finite element analysis was also used for the theoretical analyses of beat conduction and electric current flow, together with the development of imaging technique for the evaluation of the shape and size of defects. As the results of infrared measurements and theoretical analyses, the selection of heating method and the acquisition of infrared images were important for the clear image and precise measurement of weld defects. As for the clear images, the Joule effect heating was useful for the detection of open-to-the-surface defects, while the moving gas flame heating was available to the inner defect parallel to the surface. It was also clarified that the types of defects were identified by the distribution of high and low temperature regions. In the measurement of defect size, defect edges were evaluated by the positions with maximum temperature gradient in the moving gas flame heating, and with minimum second derivative of temperature in the Joule effect heating. The effective images for the precise measurement of defect size were obtained from the ones immediately after current flow in the Joule effect heating, and just before the arrival of gas flame beneath the defect.

  11. Automated diagnosis of dry eye using infrared thermography images

    NASA Astrophysics Data System (ADS)

    Acharya, U. Rajendra; Tan, Jen Hong; Koh, Joel E. W.; Sudarshan, Vidya K.; Yeo, Sharon; Too, Cheah Loon; Chua, Chua Kuang; Ng, E. Y. K.; Tong, Louis

    2015-07-01

    Dry Eye (DE) is a condition of either decreased tear production or increased tear film evaporation. Prolonged DE damages the cornea causing the corneal scarring, thinning and perforation. There is no single uniform diagnosis test available to date; combinations of diagnostic tests are to be performed to diagnose DE. The current diagnostic methods available are subjective, uncomfortable and invasive. Hence in this paper, we have developed an efficient, fast and non-invasive technique for the automated identification of normal and DE classes using infrared thermography images. The features are extracted from nonlinear method called Higher Order Spectra (HOS). Features are ranked using t-test ranking strategy. These ranked features are fed to various classifiers namely, K-Nearest Neighbor (KNN), Nave Bayesian Classifier (NBC), Decision Tree (DT), Probabilistic Neural Network (PNN), and Support Vector Machine (SVM) to select the best classifier using minimum number of features. Our proposed system is able to identify the DE and normal classes automatically with classification accuracy of 99.8%, sensitivity of 99.8%, and specificity if 99.8% for left eye using PNN and KNN classifiers. And we have reported classification accuracy of 99.8%, sensitivity of 99.9%, and specificity if 99.4% for right eye using SVM classifier with polynomial order 2 kernel.

  12. Remote monitoring of breathing dynamics using infrared thermography

    PubMed Central

    Pereira, Carina Barbosa; Yu, Xinchi; Czaplik, Michael; Rossaint, Rolf; Blazek, Vladimir; Leonhardt, Steffen

    2015-01-01

    An atypical or irregular respiratory frequency is considered to be one of the earliest markers of physiological distress. In addition, monitoring of this vital parameter plays a major role in diagnosis of respiratory disorders, as well as in early detection of sudden infant death syndrome. Nevertheless, the current measurement modalities require attachment of sensors to the patient’s body, leading to discomfort and stress. The current paper presents a new robust algorithm to remotely monitor breathing rate (BR) by using thermal imaging. This approach permits to detect and to track the region of interest (nose) as well as to estimate BR. In order to study the performance of the algorithm, and its robustness against motion and breathing disorders, three different thermal recordings of 11 healthy volunteers were acquired (sequence 1: normal breathing; sequence 2: normal breathing plus arbitrary head movements; and sequence 3: sequence of specific breathing patterns). Thoracic effort (piezoplethysmography) served as “gold standard” for validation of our results. An excellent agreement between estimated BR and ground truth was achieved. Whereas the mean correlation for sequence 1–3 were 0.968, 0.940 and 0.974, the mean absolute BR errors reached 0.33, 0.55 and 0.96 bpm (breaths per minute), respectively. In brief, this work demonstrates that infrared thermography is a promising, clinically relevant alternative for the currently available measuring modalities due to its performance and diverse remarkable advantages. PMID:26601003

  13. Assessment of Lower Limb Prosthesis through Wearable Sensors and Thermography

    PubMed Central

    Cutti, Andrea Giovanni; Perego, Paolo; Fusca, Marcello C.; Sacchetti, Rinaldo; Andreoni, Giuseppe

    2014-01-01

    This study aimed to explore the application of infrared thermography in combination with ambulatory wearable monitoring of temperature and relative humidity, to assess the residual limb-to-liner interface in lower-limb prosthesis users. Five male traumatic transtibial amputees were involved, who reported no problems or discomfort while wearing the prosthesis. A thermal imaging camera was used to measure superficial thermal distribution maps of the stump. A wearable system for recording the temperature and relative humidity in up to four anatomical points was developed, tested in vitro and integrated with the measurement set. The parallel application of an infrared camera and wearable sensors provided complementary information. Four main Regions of Interest were identified on the stump (inferior patella, lateral/medial epicondyles, tibial tuberosity), with good inter-subject repeatability. An average increase of 20% in hot areas (P < 0.05) is shown after walking compared to resting conditions. The sensors inside the cuff did not provoke any discomfort during recordings and provide an inside of the thermal exchanges while walking and recording the temperature increase (a regime value is ∼+1.1 ± 0.7 °C) and a more significant one (∼+4.1 ± 2.3%) in humidity because of the sweat produced. This study has also begun the development of a reference data set for optimal socket/liner-stump construction. PMID:24618782

  14. Study Methods to Characterize and Implement Thermography Nondestructive Evaluation (NDE)

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    1998-01-01

    The limits and conditions under which an infrared thermographic nondestructive evaluation can be utilized to assess the quality of aerospace hardware is demonstrated in this research effort. The primary focus of this work is on applying thermography to the inspection of advanced composite structures such as would be found in the International Space Station Instrumentation Racks, Space Shuttle Cargo Bay Doors, Bantam RP-1 tank or RSRM Nose Cone. Here, the detection of delamination, disbond, inclusion and porosity type defects are of primary interest. In addition to composites, an extensive research effort has been initiated to determine how well a thermographic evaluation can detect leaks and disbonds in pressurized metallic systems "i.e. the Space Shuttle Main Engine Nozzles". In either case, research into developing practical inspection procedures was conducted and thermographic inspections were performed on a myriad of test samples, subscale demonstration articles and "simulated" flight hardware. All test samples were fabricated as close to their respective structural counterparts as possible except with intentional defects for NDE qualification. As an added benefit of this effort to create simulated defects, methods were devised for defect fabrication that may be useful in future NDE qualification ventures.

  15. Detection of localized fatigue damage in steel by thermography

    NASA Astrophysics Data System (ADS)

    Medgenberg, Justus; Ummenhofer, Thomas

    2007-04-01

    Fatigue damage of unalloyed steels in the high cycle regime is governed by localized cyclic plastic deformations and subsequent crack initiation. The extent of early microplastic deformations depends on the applied stress level, stress concentration at macroscopic notches, surface treatment, residual stresses etc. The onset of a nonlinear material response can be regarded as an early indicator of fatigue damage. During fatigue loading thermoelastic coupling and thermoplastic dissipation cause characteristic temperature variations in tested specimens which have been assessed by a highly sensitive infrared camera. A specialized data processing method in the time domain has been developed which allows to separate the different contributions to the measured temperature signal. In contrast to other methods - as e.g. measuring the rise of mean temperature during fatigue loading - the proposed methodology is based on measurements during the stabilized temperature regimen and offers very high spatial resolution of localized phenomena. Investigations have been made on mildly notched cylindrical and also on welded specimens. The results confirm the close relation between the local temperature signal and typical fatigue phenomena. The new methodology allows for a much better localization and quantification of effects as cyclic plasticity, crack initiation, crack growth etc. The following paper presents considerations and experimental results of an application of thermography to the local assessment of fatigue damage.

  16. Infrared thermography based studies on mobile phone induced heating

    NASA Astrophysics Data System (ADS)

    Lahiri, B. B.; Bagavathiappan, S.; Soumya, C.; Jayakumar, T.; Philip, John

    2015-07-01

    Here, we report the skin temperature rise due to the absorption of radio frequency (RF) energy from three handheld mobile phones using infrared thermography technique. Experiments are performed under two different conditions, viz. when the mobile phones are placed in soft touch with the skin surface and away from the skin surface. Additionally, the temperature rise of mobile phones during charging, operation and simultaneous charging and talking are monitored under different exposure conditions. It is observed that the temperature of the cheek and ear regions monotonically increased with time during the usage of mobile phones and the magnitude of the temperature rise is higher for the mobile phone with higher specific absorption rate. The increase in skin temperature is higher when the mobile phones are in contact with the skin surface due to the combined effect of absorption of RF electromagnetic power and conductive heat transfer. The increase in the skin temperature in non-contact mode is found to be within the safety limit of 1 °C. The measured temperature rise is in good agreement with theoretical predictions. The empirical equation obtained from the temperature rise on the cheek region of the subjects correlates well with the specific absorption rate of the mobile phones. Our study suggests that the use of mobile phones in non-contact mode can significantly lower the skin temperature rise during its use and hence, is safer compared to the contact mode.

  17. International standards for pandemic screening using infrared thermography

    NASA Astrophysics Data System (ADS)

    Pascoe, D. D.; Ring, E. F.; Mercer, J. B.; Snell, J.; Osborn, D.; Hedley-Whyte, J.

    2010-03-01

    The threat of a virulent strain of influenza, severe acute respiratory syndrome (SARS), tuberculosis, H1N1/A virus (swine flu) and possible mutations are a constant threat to global health. Implementation of pandemic infrared thermographic screening is based on the detection of febrile temperatures (inner canthus of the eyes) that are correlated with an infectious disease. Previous attempts at pandemic thermal screening have experienced problems (e.g. SARS outbreak, Singapore 2003) associated with the deployment plan, implementation and operation of the screening thermograph. Since this outbreak, the International Electrotechnical Commission has developed international standards that set minimum requirements for thermographic system fever screening and procedures that insure reliable and reproducible measurements. These requirements are published in IEC 80601-2-59:2008, Medical electrical equipment - Part 2-59: Particular requirements for the basic safety and essential performance of screening thermographs for human febrile temperature screening. The International Organization for Standardization has developed ISO/TR 13154:2009, Medical Electrical Equipment - which provides deployment, implementation and operational guidelines for identifying febrile humans using a screening thermograph. These new standards includes recommendations for camera calibrations, use of black body radiators, view field, focus, pixels within measurement site, image positioning, and deployment locations. Many current uses of thermographic screening at airports do not take into account critical issues addressed in the new standard, and are operating below the necessary effectiveness and efficiency. These documents, related thermal research, implications for epidemiology screening, and the future impact on medical thermography are discussed.

  18. Pulse Phase Thermography for Defect Detection and Visualization

    NASA Technical Reports Server (NTRS)

    Marinetti, Sergio; Plotnikov, Yuri A.; Winfree, William P.; Braggiotti, Alberto

    1999-01-01

    Pulse Phase Thermography (PPT) has been reported as a novel powerful technique of the thermal NDE. It employs application of the Discrete Fourier Transform (DFT) to thermal images obtained following flash heating of the front surface of a specimen. The computed phasegrams are excellent for defect visualization in a wide range of materials. This is in part due to their low sensitivity to uneven heating. This work is an attempt to analyze advantages and limitations of PPT. Results of application of the DFT to simulated temperature decays are presented. The temperature evolution on a surface has been simulated based on an analytical solution of the one-dimensional heat diffusion problem. A more sophisticated study has been done for different sizes of defects using numerical solution of the three-dimensional mathematical model. Capabilities of PPT for in-depth scanning and for monitoring of the material loss are discussed. The recommendations for the practical application of the PPT are presented. Experimental results obtained following these recommendations are reported.

  19. On Field Inspection of Composite Pipes Using Pulsed Phase Thermography

    NASA Astrophysics Data System (ADS)

    Souza, M. P. V.; Almeida, R. M.; Rebello, J. M. A.; Soares, S. D.

    2010-02-01

    The pulsed phase thermography (PPT) is becoming a valuable tool on the detection and dimensioning of defects on composite materials. However, the most of the works that adopt the PPT needs very sophisticated equipment to thermal excitation of the specimen and data acquisition. This work uses the concepts of the PPT to inspect sections of fiberglass reinforced epoxy pipes used on adhesively bonded joints applied on the oil industry on extraction and transportation of fluids, using low cost and simple equipment to thermal excitation. A MatLab routine to data processing was used intending to achieve a fast and reliable non-destructive method to be performed on field. Amplitude and phase images are generated from the infrared images without any pre-processing technique revealing simulated defects that were impossible to be detected on the original data. A study of how deep the thermal wave can reach along the thickness of this kind of material is also performed trying to estipulate the limits of the technique aiming on the detection of problems on adhesive layers using two heat sources: halogen lamp and industrial air blower. Results support the possibility of implementing a reliable and low cost method of inspection on field to various values of pipe thicknesses found on plants of the oil industry.

  20. Thermography for estimating near-surface soil moisture under developing crop canopies

    NASA Technical Reports Server (NTRS)

    Heilman, J. L.; Moore, D. G.

    1980-01-01

    Previous investigations of thermal infrared techniques using remote sensors (thermography) for estimating soil water content have been limited primarily to bare soil. Ground-based and aircraft investigations were conducted to evaluate the potential for extending the thermography approach to developing crop canopies. A significant exponential relationship was found between the volumetric soil water content in the 0-4 cm soil layer and the diurnal difference between surface soil temperature measured at 0230 and 1330 LST (satellite overpass times of NASA's Heat Capacity Mapping Mission - HCMM). Surface soil temperatures were estimated using minimum air temperature, percent cover of the canopy and remote measurements of canopy temperature. Results of the investigation demonstrated that thermography can potentially be used to estimate soil temperature and soil moisture throughout a complete growing season for a number of different crops and soils.

  1. Damage Detection in Rotorcraft Composite Structures Using Thermography and Laser-Based Ultrasound

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Zalameda, Joseph N.; Madaras, Eric I.

    2004-01-01

    New rotorcraft structural composite designs incorporate lower structural weight, reduced manufacturing complexity, and improved threat protection. These new structural concepts require nondestructive evaluation inspection technologies that can potentially be field-portable and able to inspect complex geometries for damage or structural defects. Two candidate technologies were considered: Thermography and Laser-Based Ultrasound (Laser UT). Thermography and Laser UT have the advantage of being non-contact inspection methods, with Thermography being a full-field imaging method and Laser UT a point scanning technique. These techniques were used to inspect composite samples that contained both embedded flaws and impact damage of various size and shape. Results showed that the inspection techniques were able to detect both embedded and impact damage with varying degrees of success.

  2. Use of infra-red thermography for automotive climate control analysis

    SciTech Connect

    Burch, S.D.; Hassani, V.; Penney, T.R.

    1994-03-01

    In this paper, several automotive climate control applications for IR thermography are described. Some of these applications can be performed using conventional IR techniques. Others, such as visualizing the air temperature distribution within the cabin, at duct exits, and at heater and evaporator faces, require new experimental methods. In order to capture the temperature distribution within an airstream, a 0.25-mm-thick (0.01 inch) fiberglass screen is used. This screen can be positioned perpendicular or parallel to the flow to obtain three-dimensional spatial measurements. In many cases, the air flow pattern can be inferred from the resulting temperature distribution, allowing improved air distribution designs. In all cases, significant improvement in the speed, ease, and quantity of temperature distribution information can be realized with thermography as compared to conventional thermocouple array techniques. Comparisons are presented between IR thermography images and both thermocouple measurements and computational fluid dynamics (CFD) predictions.

  3. Nde of Advanced Automotive Composite Materials that Apply Ultrasound Infrared Thermography Technique

    NASA Astrophysics Data System (ADS)

    Choi, Seung-Hyun; Park, Soo-Keun; Kim, Jae-Yeol

    The infrared thermographic nondestructive inspection technique is a quality inspection and stability assessment method used to diagnose the physical characteristics and defects by detecting the infrared ray radiated from the object without destructing it. Recently, the nondestructive inspection and assessment that use the ultrasound-infrared thermography technique are widely adopted in diverse areas. The ultrasound-infrared thermography technique uses the phenomenon that the ultrasound wave incidence to an object with cracks or defects on its mating surface generates local heat on the surface. The car industry increasingly uses composite materials for their lightweight, strength, and environmental resistance. In this study, the car piston passed through the ultrasound-infrared thermography technique for nondestructive testing, among the composite material car parts. This study also examined the effects of the frequency and power to optimize the nondestructive inspection.

  4. Nondestructive test of brazed cooling tubes of prototype bolometer camera housing using active infrared thermography

    NASA Astrophysics Data System (ADS)

    Tahiliani, Kumudni; Pandya, Santosh P.; Pandya, Shwetang; Jha, Ratneshwar; Govindarajan, J.

    2011-01-01

    The active infrared thermography technique is used for assessing the brazing quality of an actively cooled bolometer camera housing developed for steady state superconducting tokamak. The housing is a circular pipe, which has circular tubes vacuum brazed on the periphery. A unique method was adopted to monitor the temperature distribution on the internal surface of the pipe. A stainless steel mirror was placed inside the pipe and the reflected IR radiations were viewed using an IR camera. The heat stimulus was given by passing hot water through the tubes and the temperature distribution was monitored during the transient phase. The thermographs showed a significant nonuniformity in the brazing with a contact area of around 51%. The thermography results were compared with the x-ray radiographs and a good match between the two was observed. Benefits of thermography over x-ray radiography testing are emphasized.

  5. Evaluation of paint coating thickness variations based on pulsed Infrared thermography laser technique

    NASA Astrophysics Data System (ADS)

    Mezghani, S.; Perrin, E.; Vrabie, V.; Bodnar, J. L.; Marthe, J.; Cauwe, B.

    2016-05-01

    In this paper, a pulsed Infrared thermography technique using a homogeneous heat provided by a laser source is used for the non-destructive evaluation of paint coating thickness variations. Firstly, numerical simulations of the thermal response of a paint coated sample are performed. By analyzing the thermal responses as a function of thermal properties and thickness of both coating and substrate layers, optimal excitation parameters of the heating source are determined. Two characteristic parameters were studied with respect to the paint coating layer thickness variations. Results obtained using an experimental test bench based on the pulsed Infrared thermography laser technique are compared with those given by a classical Eddy current technique for paint coating variations from 5 to 130 μm. These results demonstrate the efficiency of this approach and suggest that the pulsed Infrared thermography technique presents good perspectives to characterize the heterogeneity of paint coating on large scale samples with other heating sources.

  6. Thermophysical analysis of II-VI semiconductors by PPE calorimetry and lock-in thermography

    SciTech Connect

    Streza, M.; Dadarlat, D.; Strzałkowski, K.

    2013-11-13

    An accurate determination of thermophysical properties such as thermal diffusivity, thermal effusivity and thermal conductivity is extremely important for characterization and quality assurance of semiconductors. Thermal diffusivity and effusivity of some binary semiconductors have been investigated. Two experimental techniques were used: a contact technique (PPE calorimetry) and a non contact technique (lock-in thermography). When working with PPE, in the back (BPPE) configuration and in the thermally thick regim of the pyroelectric sensor, we can get the thermal diffusivity of the sample by performing a scanning of the excitation frequency of radiation. Thermal effusivity is obtained in front configuration (sensor directly irradiated and sample in back position) by performing a thickness scan of a coupling fluid. By using the lock-in thermography technique, the thermal diffusivity of the sample is obtained from the phase image. The results obtained by the two techniques are in good agreement. Nevertheless, for the determination of thermal diffusivity, lock-in thermography is preferred.

  7. Low-velocity impact damage characterization of carbon fiber reinforced polymer (CFRP) using infrared thermography

    NASA Astrophysics Data System (ADS)

    Li, Yin; Zhang, Wei; Yang, Zheng-wei; Zhang, Jin-yu; Tao, Sheng-jie

    2016-05-01

    Carbon fiber reinforced polymer (CFRP) after low-velocity impact is detected using infrared thermography, and different damages in the impacted composites are analyzed in the thermal maps. The thermal conductivity under pulse stimulation, frictional heating and thermal conductivity under ultrasonic stimulation of CFRP containing low-velocity impact damage are simulated using numerical simulation method. Then, the specimens successively exposed to the low-velocity impact are respectively detected using the pulse infrared thermography and ultrasonic infrared thermography. Through the numerical simulation and experimental investigation, the results obtained show that the combination of the above two detection methods can greatly improve the capability for detecting and evaluating the impact damage in CFRP. Different damages correspond to different infrared thermal images. The delamination damage, matrix cracking and fiber breakage are characterized as the block-shape hot spot, line-shape hot spot,

  8. Calibration and Evaluation of Ultrasound Thermography Using Infrared Imaging.

    PubMed

    Hsiao, Yi-Sing; Deng, Cheri X

    2016-02-01

    Real-time monitoring of the spatiotemporal evolution of tissue temperature is important to ensure safe and effective treatment in thermal therapies including hyperthermia and thermal ablation. Ultrasound thermography has been proposed as a non-invasive technique for temperature measurement, and accurate calibration of the temperature-dependent ultrasound signal changes against temperature is required. Here we report a method that uses infrared thermography for calibration and validation of ultrasound thermography. Using phantoms and cardiac tissue specimens subjected to high-intensity focused ultrasound heating, we simultaneously acquired ultrasound and infrared imaging data from the same surface plane of a sample. The commonly used echo time shift-based method was chosen to compute ultrasound thermometry. We first correlated the ultrasound echo time shifts with infrared-measured temperatures for material-dependent calibration and found that the calibration coefficient was positive for fat-mimicking phantom (1.49 ± 0.27) but negative for tissue-mimicking phantom (-0.59 ± 0.08) and cardiac tissue (-0.69 ± 0.18°C-mm/ns). We then obtained the estimation error of the ultrasound thermometry by comparing against the infrared-measured temperature and revealed that the error increased with decreased size of the heated region. Consistent with previous findings, the echo time shifts were no longer linearly dependent on temperature beyond 45°C-50°C in cardiac tissues. Unlike previous studies in which thermocouples or water bath techniques were used to evaluate the performance of ultrasound thermography, our results indicate that high-resolution infrared thermography is a useful tool that can be applied to evaluate and understand the limitations of ultrasound thermography methods.

  9. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, B.T.; Chou, C.H.

    1990-03-20

    A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.

  10. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, Butrus T.; Chou, Ching H.

    1990-01-01

    A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

  11. Emissivity-corrected power loss calibration for lock-in thermography measurements on silicon solar cells

    SciTech Connect

    Kasemann, Martin; Walter, Benjamin; Meinhardt, Christoph; Ebser, Jan; Kwapil, Wolfram; Warta, Wilhelm

    2008-06-01

    This paper describes power loss calibration procedures with implemented emissivity correction. The determination of our emissivity correction matrix does neither rely on blackbody reference measurements nor on the knowledge of any sample temperatures. To describe the emissivity-corrected power calibration procedures in detail, we review the theory behind lock-in thermography and show experimentally that the lock-in signal is proportional to the power dissipation in the solar cell. Experiments show the successful application of our emissivity correction procedure, which significantly improves the informative value of lock-in thermography images and the reliability of the conclusions drawn from these images.

  12. Nondestructive testing of plastered mosaics with the use of active thermography approaches

    NASA Astrophysics Data System (ADS)

    Cheilakou, Eleni; Avdelidis, Nico P.; Ibarra-Castanedo, Clemente; Koui, Maria; Bendada, Abdel Hakim; Maldague, Xavier P.

    2010-05-01

    In this work, different mosaics covered with various plasters (of thickness and compositions) were evaluated in lab by means of active long wave and mid wave thermography approaches, with the intention of detecting the tesserae beneath the plastered surface. Thermal images as well as thermal contrast curves between plastered surfaces and plastered mosaics were recorded. Special considerations concerning the applicability and accuracy of the used approaches for this specific application are presented. Results from the assessment are presented and discussed, indicating that images seeing through the mortar-plaster on plastered mosaic surfaces can be obtained using active thermography approaches.

  13. Role of thermography in the assessment of infraorbital nerve injury after malar fractures.

    PubMed

    McGimpsey, J G; Vaidya, A; Biagioni, P A; Lamey, P J

    2000-12-01

    We studied 45 patients with malar fractures who had some degree of infraorbital nerve deficit. Thermographic facial images failed to show any substantial changes in the temperature profiles of the affected and the normal control sides in relation to reco very of their facial sensation. Although some patients who had thermography on the day of injury showed significant temperature differences between the affected and the normal sides, these differences were probably the result of the acute inflammatory ch anges caused by the injury. We suggest that infrared thermography has little place in the assessment of infraorbital nerve deficits. PMID:11092769

  14. Non-destructive Testing by Infrared Thermography Under Random Excitation and ARMA Analysis

    NASA Astrophysics Data System (ADS)

    Bodnar, J. L.; Nicolas, J. L.; Candoré, J. C.; Detalle, V.

    2012-11-01

    Photothermal thermography is a non-destructive testing (NDT) method, which has many applications in the field of control and characterization of thin materials. This technique is usually implemented under CW or flash excitation. Such excitations are not adapted for control of fragile materials or for multi-frequency analysis. To allow these analyses, in this article, the use of a new control mode is proposed: infrared thermography under random excitation and auto regressive moving average analysis. First, the principle of this NDT method is presented. Then, the method is shown to permit detection, with low energy constraints, of detachments situated in mural paintings.

  15. A comparison of thermography, radioisotope scanning and clinical assessment of the knee joints in haemophilia.

    PubMed

    Forbes, C D; James, W; Prentice, C R; Greig, W R

    1975-01-01

    Thermography, radioactive scanning and clinical assessment of the knee joints of a series of patients with haemophilia or Christmas disease have been performed. A positive correlation was found between the abnormalities of the thermograms, radioactive scans and the clinical signs in acute haemarthrosis, but not in chronic haemophilic joint disease nor in patients without clinical joint disease. No correlation between the thermograms, radioactive scans and the number of previous joint bleeds was shown. Thermography and radionuclide scanning provide rapid means of quantifying changes within the haemophilic joint and may be useful in assessing treatment of haemophilic haemarthrosis.

  16. Medical Acoustics

    NASA Astrophysics Data System (ADS)

    Beach, Kirk W.; Dunmire, Barbrina

    Medical acoustics can be subdivided into diagnostics and therapy. Diagnostics are further separated into auditory and ultrasonic methods, and both employ low amplitudes. Therapy (excluding medical advice) uses ultrasound for heating, cooking, permeablizing, activating and fracturing tissues and structures within the body, usually at much higher amplitudes than in diagnostics. Because ultrasound is a wave, linear wave physics are generally applicable, but recently nonlinear effects have become more important, even in low-intensity diagnostic applications.

  17. Evaluation of Microbolometer-Based Thermography for Gossamer Space Structures

    NASA Technical Reports Server (NTRS)

    Miles, Jonathan J.; Blandino, Joseph R.; Jenkins, Christopher H.; Pappa, Richard S.; Banik, Jeremy; Brown, Hunter; McEvoy, Kiley

    2005-01-01

    In August 2003, NASA's In-Space Propulsion Program contracted with our team to develop a prototype on-board Optical Diagnostics System (ODS) for solar sail flight tests. The ODS is intended to monitor sail deployment as well as structural and thermal behavior, and to validate computational models for use in designing future solar sail missions. This paper focuses on the thermography aspects of the ODS. A thermal model was developed to predict local sail temperature variations as a function of sail tilt to the sun, billow depth, and spectral optical properties of front and back sail surfaces. Temperature variations as small as 0.5 C can induce significant thermal strains that compare in magnitude to mechanical strains. These thermally induced strains may result in changes in shape and dynamics. The model also gave insight into the range and sensitivity required for in-flight thermal measurements and supported the development of an ABAQUS-coupled thermo-structural model. The paper also discusses three kinds of tests conducted to 1) determine the optical properties of candidate materials; 2) evaluate uncooled microbolometer-type infrared imagers; and 3) operate a prototype imager with the ODS baseline configuration. (Uncooled bolometers are less sensitive than cooled ones, but may be necessary because of restrictive ODS mass and power limits.) The team measured the spectral properties of several coated polymer samples at various angles of incidence. Two commercially available uncooled microbolometer imagers were compared, and it was found that reliable temperature measurements are feasible for both coated and uncoated sides of typical sail membrane materials.

  18. Using aerial infrared thermography to detect utility theft of service

    NASA Astrophysics Data System (ADS)

    Stockton, Gregory R.; Lucas, R. Gillem

    2012-06-01

    Natural gas and electric utility companies, public utility commissions, consumer advocacy groups, city governments, state governments and the federal government United States continue to turn a blind eye towards utility energy theft of service which we conservatively estimate is in excess of 10 billion a year. Why? Many in the United States have exhausted their unemployment benefits. The amounts for federal funding for low income heating assistance programs (LIHEAP) funds were cut by nearly 40% for 2012 to 3.02 billion. "At peak funding ($5.1 billion in 2009), the program was national in scale but still only had enough resources to support roughly 1/4 of the eligible households.i" Contributions to charities are down and the number of families below the poverty line who are unable to pay to heat their houses continues to rise. Many of the less fortunate in our society now consider theft and fraud to be an attractive option for their supply of natural gas and/or electricity. A record high mild winter in 2011-2012 coupled with 10-year low natural gas prices temporarily obscured the need for low income heating assistance programs (LIHEAPs) from the news and federal budgets, but cold winters will return. The proliferation of smart meters and automated meter infrastructures across our nation can do little to detect energy theft because the thieves can simply by-pass the meters, jumper around the meters and/or steal meters from abandoned houses and use them. Many utility systems were never set-up to stop these types of theft. Even with low-cost per identified thief method using aerial infrared thermography, utilities continue to ignore theft detection.

  19. Acoustic Tooth Cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1984-01-01

    Acoustically-energized water jet aids in plaque breakdown. Acoustic Wand includes acoustic transducer 1/4 wave plate, and tapered cone. Together elements energize solution of water containing mild abrasive injected into mouth to help prevent calculous buildup.

  20. A new measurement method of coatings thickness based on lock-in thermography

    NASA Astrophysics Data System (ADS)

    Zhang, Jin-Yu; Meng, Xiang-bin; Ma, Yong-chao

    2016-05-01

    Coatings have been widely used in modern industry and it plays an important role. Coatings thickness is directly related to the performance of the functional coatings, therefore, rapid and accurate coatings thickness inspection has great significance. Existing coatings thickness measurement method is difficult to achieve fast and accurate on-site non-destructive coatings inspection due to cost, accuracy, destruction during inspection and other reasons. This paper starts from the introduction of the principle of lock-in thermography, and then performs an in-depth study on the application of lock-in thermography in coatings inspection through numerical modeling and analysis. The numerical analysis helps explore the relationship between coatings thickness and phase, and the relationship lays the foundation for accurate calculation of coatings thickness. The author sets up a lock-in thermography inspection system and uses thermal barrier coatings specimens to conduct an experiment. The specimen coatings thickness is measured and calibrated to verify the quantitative inspection. Experiment results show that the lock-in thermography method can perform fast coatings inspection and the inspection accuracy is about 95%. Therefore, the method can meet the field testing requirements for engineering projects.

  1. Fabrication of 0.0075-Scale Orbiter Phosphor Thermography Test Models for Shuttle RTF Aeroheating Studies

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M.; Powers, Michael A.; Griffith, Mark S.; Hopins, John W.; Veneris, Pete H.; Kuykendoll, Kathryn

    2006-01-01

    This report details the techniques and fidelity associated with aeroheating models constructed in support of the return-to-flight boundary layer transition (BLT) activity for STS-114. This report provides technical descriptions of the methods, materials, and equipment used, as well as the surface quality results obtained with the cast ceramic phosphor thermography models.

  2. Robust, automated processing of IR thermography for quantitative boundary-layer transition measurements

    NASA Astrophysics Data System (ADS)

    Crawford, Brian K.; Duncan, Glen T.; West, David E.; Saric, William S.

    2015-07-01

    A technique for automated, quantitative, global boundary-layer transition detection using IR thermography is developed. Transition data are rigorously mapped onto model coordinates in an automated fashion on moving targets. Statistical analysis of transition data that is robust to environmental contamination is presented.

  3. Lock-in thermography for evaluation of destruction area and determination of depth

    NASA Astrophysics Data System (ADS)

    Wang, Zijun; Liu, Junyan; Dai, Jingmin

    2007-12-01

    Infrared Thermography is a Nondestructive Testing and Evaluating (NDT&E) technique that allows the non-contact inspection of systems and materials through a mapping of thermal patterns on the surface of the objects of interest. Defect detection principle in active thermography is based on the fact that a difference of thermal properties exists between the sound area and a defective region, which can be used for defect detection and quantification purposes. In this paper, experimental studies were made on the applicability to the detection of artificial defects in a steel flat plate with 12 flat-bottomed holes with three different sizes located at three different depths. The object was periodically heated by quartz lamps combined with light controller. The controller was operated by the same reference signal for the lock-in thermography. It was found that the defects were detected by localized contrast change in the phase delay images. It was also found that the location and size of defects can be estimated by the area of contrast change in the phase delay images which was clearly observed compared with conventional thermography techniques. The relationship between the values of phase delay and heating periods or modulation frequency was examined for several defect depths.

  4. Acoustic transducer

    DOEpatents

    Drumheller, D.S.

    1997-12-30

    An acoustic transducer is described comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2,000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers. 4 figs.

  5. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    1997-01-01

    An acoustic transducer comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers.

  6. Spatially resolved determination of the short-circuit current density of silicon solar cells via lock-in thermography

    SciTech Connect

    Fertig, Fabian Greulich, Johannes; Rein, Stefan

    2014-05-19

    We present a spatially resolved method to determine the short-circuit current density of crystalline silicon solar cells by means of lock-in thermography. The method utilizes the property of crystalline silicon solar cells that the short-circuit current does not differ significantly from the illuminated current under moderate reverse bias. Since lock-in thermography images locally dissipated power density, this information is exploited to extract values of spatially resolved current density under short-circuit conditions. In order to obtain an accurate result, one or two illuminated lock-in thermography images and one dark lock-in thermography image need to be recorded. The method can be simplified in a way that only one image is required to generate a meaningful short-circuit current density map. The proposed method is theoretically motivated, and experimentally validated for monochromatic illumination in comparison to the reference method of light-beam induced current.

  7. Finite element modeling of haptic thermography: A novel approach for brain tumor detection during minimally invasive neurosurgery.

    PubMed

    Sadeghi-Goughari, Moslem; Mojra, Afsaneh

    2015-10-01

    Intraoperative Thermal Imaging (ITI) is a novel neuroimaging method that can potentially locate tissue abnormalities and hence improves surgeon's diagnostic ability. In the present study, thermography technique coupled with artificial tactile sensing method called "haptic thermography" is utilized to investigate the presence of an abnormal object as a tumor with an elevated temperature relative to the normal tissue in the brain. The brain tissue is characterized as a hyper-viscoelastic material to be descriptive of mechanical behavior of the brain tissue during tactile palpation. Based on a finite element approach, Magnetic Resonance Imaging (MRI) data of a patient diagnosed to have a brain tumor is utilized to simulate and analyze the capability of haptic thermography in detection and localization of brain tumor. Steady-state thermal results prove that temperature distribution is an appropriate outcome of haptic thermography for the superficial tumors while heat flux distribution can be used as an extra thermal result for deeply located tumors. PMID:26590456

  8. Integration of reflectances and thermography imagery for transport infrastructures diagnostics

    NASA Astrophysics Data System (ADS)

    Pignatti, S.; Palombo, A.; Pascucci, S.; Santini, F.

    2012-04-01

    The integrated use of reflectances and thermography to study and diagnostic of transport infrastructures has been applied on the Musumeci Bridge (Potenza, Italy) test site as a fast and non-destructive tool in the framework of the Integrated System for Transport Infrastructures surveillance and Monitoring by Electromagnetic Sensing (ISTIMES) project, funded by the European Commission in the frame of a joint Call "ICT and Security" of the Seventh Framework Programme, in order to extract appropriate information and make useful decisions [1]. The applied hyperspectral imagery is primarily suited for the detection and characterization of alterations and defects in the structures' surface, whereas by means of thermography it is possible to attain near real-time information about the internal structure such as a bridge. Hyperspectral data is able to discriminate materials on the basis of their different patterns of wavelength-specific absorption; in fact, they are successfully used for identifying minerals and rocks, as well as detecting surface materials properties [2]. For this study we used the HySpex VNIR-1600 and the SWIR-320 hyperspectral scanners (see details in Table 1) located beneath the Musmeci Bridge thus being able to acquire the structure. The hyperspectral data processing has allowed to derive indication/parameters related to the status of the structure surface, i.e. by means of the detection of the surface weathering status of the iron (i.e. iron oxides such as limonite/goethite) used to reinforce the cement structure and the occurring detachments of the cement covering the iron. This assessment can be used to foresee more severe damages of the armed concrete. Concerning the rationale for using a high sensitivity Infrared camera in the MWIR range (3.5-5 micron; see Table 1) for the Musumeci test site is based on the fact that the high radiometric resolution of the thermal images time series allows analyzing the structure homogeneity and the cohesion of

  9. Acoustic emission descriptors

    NASA Astrophysics Data System (ADS)

    Witos, Franciszek; Malecki, Ignacy

    The authors present selected problems associated with acoustic emission interpreted as a physical phenomenon and as a measurement technique. The authors examine point sources of acoustic emission in isotropic, homogeneous linearly elastic media of different shapes. In the case of an unbounded medium the authors give the analytical form of the stress field and the wave shift field of the acoustic emission. In the case of a medium which is unbounded plate the authors give a form for the equations which is suitable for numerical calculation of the changes over time of selected acoustic emission values. For acoustic emission as a measurement technique, the authors represent the output signal as the resultant of a mechanical input value which describes the source, the transient function of the medium, and the transient function of specific components of the measurement loop. As an effect of this notation, the authors introduce the distinction between an acoustic measurement signal and an acoustic measurement impulse. The authors define the basic parameters of an arbitrary impulse. The authors extensively discuss the signal functions of acoustic emission impulses and acoustic emission signals defined in this article as acoustic emission descriptors (or signal functions of acoustic emission impulses) and advanced acoustic emission descriptors (which are either descriptors associated with acoustic emission applications or the signal functions of acoustic emission signals). The article also contains the results of experimental research on three different problems in which acoustic emission descriptors associated with acoustic emission pulses, acoustic emission applications, and acoustic emission signals are used. These problems are respectively: a problem of the amplitude-load characteristics of acoustic emission pulses in carbon samples subjected to compound uniaxial compression, the use of acoustic emission to predict the durability characteristics of conveyor belts, and

  10. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  11. Acoustic cryocooler

    DOEpatents

    Swift, Gregory W.; Martin, Richard A.; Radenbaugh, Ray

    1990-01-01

    An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintian a cooling load of 5 W at 80 K.

  12. Acoustic telemetry.

    SciTech Connect

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  13. The Role of Infrared Thermography as a Non-Invasive Tool for the Detection of Lameness in Cattle

    PubMed Central

    Alsaaod, Maher; Schaefer, Allan L.; Büscher, Wolfgang; Steiner, Adrian

    2015-01-01

    The use of infrared thermography for the identification of lameness in cattle has increased in recent years largely because of its non-invasive properties, ease of automation and continued cost reductions. Thermography can be used to identify and determine thermal abnormalities in animals by characterizing an increase or decrease in the surface temperature of their skin. The variation in superficial thermal patterns resulting from changes in blood flow in particular can be used to detect inflammation or injury associated with conditions such as foot lesions. Thermography has been used not only as a diagnostic tool, but also to evaluate routine farm management. Since 2000, 14 peer reviewed papers which discuss the assessment of thermography to identify and manage lameness in cattle have been published. There was a large difference in thermography performance in these reported studies. However, thermography was demonstrated to have utility for the detection of contralateral temperature difference and maximum foot temperature on areas of interest. Also apparent in these publications was that a controlled environment is an important issue that should be considered before image scanning. PMID:26094632

  14. Prospects and limitations of digital Shearography and Active Thermography in finding and rating flaws in CFRP sandwich parts with honeycomb core

    NASA Astrophysics Data System (ADS)

    Gruber, J.; Mayr, G.; Hendorfer, G.

    2012-05-01

    This work shows the prospects and limitations of the non-destructive testing methods Digital Shearography and Active Thermography when applied to CFRP sandwich parts with honeycomb cores. Two specimens with different core materials (aluminum, NOMEX) and artificial flaws such as delaminations, disbonds and inclusions of foreign material, are tested with Digital Shearography and Pulse Thermography including Pulse Phase Thermography. Both methods provide a good ability for finding and rating the flaws.

  15. Depth-Penetrating Luminescence Thermography of Thermal- Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Eldridge, Jeffrey

    2005-01-01

    A thermographic method has been developed for measuring temperatures at predetermined depths within dielectric material layers . especially thermal-barrier coatings. This method will help satisfy a need for noncontact measurement of through-the-thickness temperature gradients for evaluating the effectiveness of thermal- barrier coatings designed to prevent overheating of turbine blades, combustor liners, and other engine parts. Heretofore, thermography has been limited to measurement of surface and near-surface temperatures. In the thermographic method that is the immediate predecessor of the present method, a thermographic phosphor is applied to the outer surface of a thermal barrier coating, luminescence in the phosphor is excited by illuminating the phosphor at a suitable wavelength, and either the time dependence of the intensity of luminescence or the intensities of luminescence spectral lines is measured. Then an emissivity-independent surface-temperature value is computed by use of either the known temperature dependence of the luminescence decay time or the known temperature dependence of ratios between intensities of selected luminescence spectral lines. Until now, depth-penetrating measurements have not been possible because light of the wavelengths needed to excite phosphors could not penetrate thermal-barrier coating materials to useful depths. In the present method as in the method described above, one exploits the temperature dependence of luminescence decay time. In this case, the phosphor is incorporated into the thermal-barrier coat at the depth at which temperature is to be measured. To be suitable for use in this method, a phosphor must (1) exhibit a temperature dependence of luminescence decay time in the desired range, (2) be thermochemically compatible with the thermal-barrier coating, and (3) exhibit at least a minor excitation spectral peak and an emission spectral peak, both peaks being at wavelengths at which the thermal-barrier coating is

  16. Analyzing changes in the beef cattle ranching communities of acatic and tepatitlan de morelos, jalisco, Mexico related to land cover and climate variability

    NASA Astrophysics Data System (ADS)

    Trevino-Pena, Melva B.

    The impacts of climate change on the environment at the global scale can be determined through the use of large-scale circulation models; however, the results from these models are difficult to interpret at the regional or local levels. Regional vulnerability analyses consider the knowledge of locals, which may provide insight into the effects of climate variability on the environment at smaller scales, and most importantly, the effects that these developments are having on society. The objective of this research was to analyze the vulnerability to climate variability of the beef cattle ranching communities of the municipalities of Acatic and of Tepatitlan de Morelos, Jalisco, Mexico. These municipalities are found in a region of the state referred to as "Los Altos". The economy of Los Altos largely relies on agricultural and farming practices; these sectors provide the largest source of employment in the area. In the two municipalities that comprise the study area, the beef cattle industry is one of the strongest economic activities. Climate variability poses great threat on these communities because the main economic activities of the region are highly dependent on natural resources. To have a better understanding of the human-environment interactions in this region, remote sensing methods were applied. Three Landsat Thematic Mapper (TM) images (years: 1985, 1993 and 2000) were employed to generate land use and land cover classification maps of the study area; these maps were then subjected to a change detections analysis. Some of the land use and land cover categories experienced more change than others; among those was the category of water, shrub land and crop land. The area covered by water nearly doubled from 1985 to 1993 and then nearly decreased by half by the year 2000. From 1985 to 1993, here was a decrease in the shrub land of about 1200 ha and concurrently an increase in the crop land of about 1400 ha. From 1993 to 2000 there was an increase in the

  17. Field test of infrared thermography applied to biogas controlling in landfill sites

    NASA Astrophysics Data System (ADS)

    Madruga, Francisco J.; Muñoz, Jaime M.; González, Daniel A.; Tejero, Juan I.; Cobo, Adolfo; Gil, José L.; Conde, Olga M.; López-Higuera, Jose M.

    2007-04-01

    The gases accumulated inside the landfill as result of the fermentation of Municipal Solid Waste (MSW) known as biogas, are taking into consideration all possible uses as direct transformation into electricity. The system for collecting, regulating and controlling the biogas must include all the necessary safety features where the biogas leakage presents a high impact. Infrared thermography can be use to detect gas leakages due to the differences in temperature between the gas and the immediate surroundings. This method is able to monitor a wide area of landfill sites, quickly. This technology will not be effective if the differences in temperature are not better than five degrees. This paper describes a field test conducted to study the limitations of the infrared thermography caused by weather conditions and the moment of day or/and season when the thermal images was captured. Pipelines, borders, cells, covers, slopes and leakage (hot spots) are studied and optimum conditions are defined.

  18. Electromagnetic Thermography Nondestructive Evaluation: Physics-based Modeling and Pattern Mining

    PubMed Central

    Gao, Bin; Woo, Wai Lok; Tian, Gui Yun

    2016-01-01

    Electromagnetic mechanism of Joule heating and thermal conduction on conductive material characterization broadens their scope for implementation in real thermography based Nondestructive testing and evaluation (NDT&E) systems by imparting sensitivity, conformability and allowing fast and imaging detection, which is necessary for efficiency. The issue of automatic material evaluation has not been fully addressed by researchers and it marks a crucial first step to analyzing the structural health of the material, which in turn sheds light on understanding the production of the defects mechanisms. In this study, we bridge the gap between the physics world and mathematical modeling world. We generate physics-mathematical modeling and mining route in the spatial-, time-, frequency-, and sparse-pattern domains. This is a significant step towards realizing the deeper insight in electromagnetic thermography (EMT) and automatic defect identification. This renders the EMT a promising candidate for the highly efficient and yet flexible NDT&E. PMID:27158061

  19. Reconstruction of a nonlinear heat transfer law from uncomplete boundary data by means of infrared thermography

    NASA Astrophysics Data System (ADS)

    Clarelli, Fabrizio; Inglese, Gabriele

    2016-11-01

    Heat exchange between a conducting plate and the environment is described here by means of an unknown nonlinear function F of the temperature u. In this paper we construct a method for recovering F by means of polynomial expansion, perturbation theory and the toolbox of thermal inverse problems. We test our method on two examples: In the first one, we heat the plate (initially at 20 ^\\circ {{C}}) from one side, read the temperature on the same side and identify the heat exchange law on the opposite side (active thermography); in the second example we measure the temperature of one side of the plate (initially at 1500 ^\\circ {{C}}) and study the heat exchange while cooling (passive thermography).

  20. Quantitative analysis of pulse thermography data for degradation assessment of historical buildings

    NASA Astrophysics Data System (ADS)

    Di Maio, Rosa; Piegari, Ester; Mancini, Cecilia; Chiapparino, Antonella

    2015-06-01

    In the last decades, infrared thermography has been successfully applied to various materials and structures for the assessment of their state of conservation and planning suitable restoration works. To this aim, mathematical models are required to characterize thermal anomaly sources, such as detachments, water infiltration and material decomposition processes. In this paper, an algorithm based on the conservative finite difference method is used to analyse pulse thermography data acquired on an ancient building in the Pompeii archaeological site (Naples, Italy). The numerical study is applied to both broad and narrow elongated thermal anomalies. In particular, from the comparison between simulated and experimental thermal decays, the plaster thickness was characterized in terms of thermal properties and areas of possible future detachments, and moisture infiltration depths were identified.

  1. Evaluation of the diagnostic power of thermography in breast cancer using Bayesian network classifiers.

    PubMed

    Nicandro, Cruz-Ramírez; Efrén, Mezura-Montes; María Yaneli, Ameca-Alducin; Enrique, Martín-Del-Campo-Mena; Héctor Gabriel, Acosta-Mesa; Nancy, Pérez-Castro; Alejandro, Guerra-Hernández; Guillermo de Jesús, Hoyos-Rivera; Rocío Erandi, Barrientos-Martínez

    2013-01-01

    Breast cancer is one of the leading causes of death among women worldwide. There are a number of techniques used for diagnosing this disease: mammography, ultrasound, and biopsy, among others. Each of these has well-known advantages and disadvantages. A relatively new method, based on the temperature a tumor may produce, has recently been explored: thermography. In this paper, we will evaluate the diagnostic power of thermography in breast cancer using Bayesian network classifiers. We will show how the information provided by the thermal image can be used in order to characterize patients suspected of having cancer. Our main contribution is the proposal of a score, based on the aforementioned information, that could help distinguish sick patients from healthy ones. Our main results suggest the potential of this technique in such a goal but also show its main limitations that have to be overcome to consider it as an effective diagnosis complementary tool.

  2. Electromagnetic Thermography Nondestructive Evaluation: Physics-based Modeling and Pattern Mining.

    PubMed

    Gao, Bin; Woo, Wai Lok; Tian, Gui Yun

    2016-01-01

    Electromagnetic mechanism of Joule heating and thermal conduction on conductive material characterization broadens their scope for implementation in real thermography based Nondestructive testing and evaluation (NDT&E) systems by imparting sensitivity, conformability and allowing fast and imaging detection, which is necessary for efficiency. The issue of automatic material evaluation has not been fully addressed by researchers and it marks a crucial first step to analyzing the structural health of the material, which in turn sheds light on understanding the production of the defects mechanisms. In this study, we bridge the gap between the physics world and mathematical modeling world. We generate physics-mathematical modeling and mining route in the spatial-, time-, frequency-, and sparse-pattern domains. This is a significant step towards realizing the deeper insight in electromagnetic thermography (EMT) and automatic defect identification. This renders the EMT a promising candidate for the highly efficient and yet flexible NDT&E. PMID:27158061

  3. Is it possible to revive the flagging interest in thermography for neurology?

    NASA Astrophysics Data System (ADS)

    Stulin, Igor D.

    1993-11-01

    The paper describes the results of twenty-years of experience in applying thermography (thermal imaging) in routine and urgent neurology, based on the study of more than ten thousand patients. Stress is laid on the fact that thermography is of great significance for diagnosing dextrocerebral hemorrhagic insult with a manifestation of pronounced hemihypothermia in the paralyzed limbs, identifying paraorbital hyperthermia on the side of rhinogenous cerebral abscess, for instrumental registration of transitory heat-up of the nasolabial region in the case of patients suffering from hypertensive nasal bleeding. Much attention is given to diagnosis of intra- and extracerebral phlebopathy in urgent neurology -- early diagnosis of iatrogenic catheterization phlebitis, interference with the venous return in the paralyzed lower limb. The novelty here is the employment of telethermography for complex diagnosis of cerebral death.

  4. Evaluation of the diagnostic power of thermography in breast cancer using Bayesian network classifiers.

    PubMed

    Nicandro, Cruz-Ramírez; Efrén, Mezura-Montes; María Yaneli, Ameca-Alducin; Enrique, Martín-Del-Campo-Mena; Héctor Gabriel, Acosta-Mesa; Nancy, Pérez-Castro; Alejandro, Guerra-Hernández; Guillermo de Jesús, Hoyos-Rivera; Rocío Erandi, Barrientos-Martínez

    2013-01-01

    Breast cancer is one of the leading causes of death among women worldwide. There are a number of techniques used for diagnosing this disease: mammography, ultrasound, and biopsy, among others. Each of these has well-known advantages and disadvantages. A relatively new method, based on the temperature a tumor may produce, has recently been explored: thermography. In this paper, we will evaluate the diagnostic power of thermography in breast cancer using Bayesian network classifiers. We will show how the information provided by the thermal image can be used in order to characterize patients suspected of having cancer. Our main contribution is the proposal of a score, based on the aforementioned information, that could help distinguish sick patients from healthy ones. Our main results suggest the potential of this technique in such a goal but also show its main limitations that have to be overcome to consider it as an effective diagnosis complementary tool. PMID:23762182

  5. Evaluation of the Diagnostic Power of Thermography in Breast Cancer Using Bayesian Network Classifiers

    PubMed Central

    Nicandro, Cruz-Ramírez; Efrén, Mezura-Montes; María Yaneli, Ameca-Alducin; Enrique, Martín-Del-Campo-Mena; Héctor Gabriel, Acosta-Mesa; Nancy, Pérez-Castro; Alejandro, Guerra-Hernández; Guillermo de Jesús, Hoyos-Rivera; Rocío Erandi, Barrientos-Martínez

    2013-01-01

    Breast cancer is one of the leading causes of death among women worldwide. There are a number of techniques used for diagnosing this disease: mammography, ultrasound, and biopsy, among others. Each of these has well-known advantages and disadvantages. A relatively new method, based on the temperature a tumor may produce, has recently been explored: thermography. In this paper, we will evaluate the diagnostic power of thermography in breast cancer using Bayesian network classifiers. We will show how the information provided by the thermal image can be used in order to characterize patients suspected of having cancer. Our main contribution is the proposal of a score, based on the aforementioned information, that could help distinguish sick patients from healthy ones. Our main results suggest the potential of this technique in such a goal but also show its main limitations that have to be overcome to consider it as an effective diagnosis complementary tool. PMID:23762182

  6. Heat transfer measurements in ONERA supersonic and hypersonic wind tunnels using passive and active infrared thermography

    NASA Astrophysics Data System (ADS)

    Balageas, D.; Boscher, D.; Deom, A.; Gardette, G.

    Over the past few years, a major intellectual and technical investment has been made at ONERA to use data acquisition systems and data reduction procedures using an infrared camera as a detector under routine wind tunnel conditions. This allows a really quantitative mapping of heat transfer rate distributions on models in supersonic and hypersonic flows. Sufficient experience has now been acquired to allow us to give an overview of: (1) the systems and data reduction procedures developed for both passive and active methods; (2) typical results obtained on various configurations such as supersonic axisymmetrical flow around an ogival body (passive and active thermography), heat flux modulation in the reattachment zone of a flap in hypersonic regime, transitional heating on very slightly blunted spheroconical bodies in hypersonic flows, and materials testing in high-enthalpy hypersonic flow (passive thermography).

  7. Infrared thermography-based visualization of droplet transport in liquid sprays

    NASA Astrophysics Data System (ADS)

    Akafuah, Nelson K.; Salazar, Abraham J.; Saito, Kozo

    2010-05-01

    An infrared thermography-based technique for the characterization and visualization of liquid sprays was developed. The technique was tested on two atomizers: a high-speed rotary bell atomizer and a high volume low pressure air-assisted atomizer. The technique uses an infrared thermography-based measurement in which a uniformly heated background acts as a thermal radiation source, and an infrared camera as the receiver. The infrared energy emitted by the radiation source in traveling through the spray is attenuated by the presence of the droplets inside the spray. The infrared intensity is captured by the receiver showing the attenuation in the image as a result of the presence of the spray. The captured thermal image is used to study detailed macroscopic features of the spray flow field and the evolution of the paint droplets as they are transferred from the applicator to the target surface.

  8. Modeling of the ITER-like wide-angle infrared thermography view of JET.

    PubMed

    Aumeunier, M-H; Firdaouss, M; Travère, J-M; Loarer, T; Gauthier, E; Martin, V; Chabaud, D; Humbert, E

    2012-10-01

    Infrared (IR) thermography systems are mandatory to ensure safe plasma operation in fusion devices. However, IR measurements are made much more complicated in metallic environment because of the spurious contributions of the reflected fluxes. This paper presents a full predictive photonic simulation able to assess accurately the surface temperature measurement with classical IR thermography from a given plasma scenario and by taking into account the optical properties of PFCs materials. This simulation has been carried out the ITER-like wide angle infrared camera view of JET in comparing with experimental data. The consequences and the effects of the low emissivity and the bidirectional reflectivity distribution function used in the model for the metallic PFCs on the contribution of the reflected flux in the analysis are discussed.

  9. Assessment of techniques of massage and pumping in the treatment of breast engorgement by thermography

    PubMed Central

    Heberle, Anita Batista dos Santos; de Moura, Marcos Antônio Muniz; de Souza, Mauren Abreu; Nohama, Percy

    2014-01-01

    Objective to evaluate techniques of massage and pumping in the treatment of postpartum breast engorgement through thermography. Method the study was conducted in the Human Milk Bank of a hospital in Curitiba, Brazil. We randomly selected 16 lactating women with engorgement with the classification lobar, ampullary and glandular, moderate and intense. We compared the differential patterns of temperature, before and after the treatment by means of massage and pumping. Results we found a negative gradient of 0.3°C of temperature between the pre- and post-treatment in the experimental group. Breasts with intense engorgement were 0.7°C warmer when compared with moderate engorgement. Conclusion massage and electromechanical pumping were superior to manual methods when evaluated by thermography. REBEC: U1111-1136-9027. PMID:26107836

  10. Intraoperative imaging of cortical cerebral perfusion by time-resolved thermography and multivariate data analysis

    NASA Astrophysics Data System (ADS)

    Steiner, Gerald; Sobottka, Stephan B.; Koch, Edmund; Schackert, Gabriele; Kirsch, Matthias

    2011-01-01

    A new approach to cortical perfusion imaging is demonstrated using high-sensitivity thermography in conjunction with multivariate statistical data analysis. Local temperature changes caused by a cold bolus are imaged and transferred to a false color image. A cold bolus of 10 ml saline at ice temperature is injected systemically via a central venous access. During the injection, a sequence of 735 thermographic images are recorded within 2 min. The recorded data cube is subjected to a principal component analysis (PCA) to select slight changes of the cortical temperature caused by the cold bolus. PCA reveals that 11 s after injection the temperature of blood vessels is shortly decreased followed by an increase to the temperature before the cold bolus is injected. We demonstrate the potential of intraoperative thermography in combination with multivariate data analysis to image cortical cerebral perfusion without any markers. We provide the first in vivo application of multivariate thermographic imaging.

  11. Quantitative detection of defects based on Markov-PCA-BP algorithm using pulsed infrared thermography technology

    NASA Astrophysics Data System (ADS)

    Tang, Qingju; Dai, Jingmin; Liu, Junyan; Liu, Chunsheng; Liu, Yuanlin; Ren, Chunping

    2016-07-01

    Quantitative detection of debonding defects' diameter and depth in TBCs has been carried out using pulsed infrared thermography technology. By combining principal component analysis with neural network theory, the Markov-PCA-BP algorithm was proposed. The principle and realization process of the proposed algorithm was described. In the prediction model, the principal components which can reflect most characteristics of the thermal wave signal were set as the input, and the defect depth and diameter was set as the output. The experimental data from pulsed infrared thermography tests of TBCs with flat bottom hole defects was selected as the training and testing sample. Markov-PCA-BP predictive system was arrived, based on which both the defect depth and diameter were identified accurately, which proved the effectiveness of the proposed method for quantitative detection of debonding defects in TBCs.

  12. Depth estimation of surface cracks on metallic components by means of lock-in thermography

    NASA Astrophysics Data System (ADS)

    Streza, M.; Dadarlat, D.; Fedala, Y.; Longuemart, S.

    2013-07-01

    In this work, a new method to characterize vertical cracks by lock-in thermography is presented. The heat transfer process induced by a modulated thermal excitation located in the vicinity of the crack is simulated using a finite element method computer package. The propagation of heat flow along the solid surface is disturbed when crossing an inhomogeneity. The disturbance of the thermal-wave allows a quantitative analysis of the crack. The main idea consists of exploiting the second derivative of the amplitude image in order to highlight the useful signal. In addition, an image analysis procedure based on the use of Laplacian calculations is proposed. To support this approach, experimental tests were performed and compared with mathematical simulations. The results demonstrate the potential of active lock-in thermography as a contactless tool for crack-depth estimation.

  13. Acoustic hemostasis

    NASA Astrophysics Data System (ADS)

    Crum, Lawrence; Beach, Kirk; Carter, Stephen; Chandler, Wayne; Curra, Francesco; Kaczkowski, Peter; Keilman, George; Khokhlova, Vera; Martin, Roy; Mourad, Pierre; Vaezy, Shahram

    2000-07-01

    In cases of severe injury, physicians speak of a "golden hour"—a brief grace period in which quickly applied, proper therapy can save the life of the patient. Much of this mortality results from exsanguination, i.e., bleeding to death—often from internal hemorrhage. The inability of a paramedic to treat breaches in the vascular system deep within the body or to stem the loss of blood from internal organs is a major reason for the high level of mortality associated with blunt trauma. We have undertaken an extensive research program to treat the problem of internal bleeding. Our approach is as follows: (a) We use scanning ultrasound to identify internal bleeding and hemorrhage, (b) we use ultrasound imaging to locate specific breaches in the vascular system, both from damaged vessels and gross damage to the capillary bed, and (c) we use High Intensity Focused Ultrasound (HIFU) to treat the damaged region and to induce hemostasis. We present a general review of this research with some emphasis on the role of nonlinear acoustics.

  14. Detection and Characterization of Boundary-Layer Transition in Flight at Supersonic Conditions Using Infrared Thermography

    NASA Technical Reports Server (NTRS)

    Banks, Daniel W.

    2008-01-01

    Infrared thermography is a powerful tool for investigating fluid mechanics on flight vehicles. (Can be used to visualize and characterize transition, shock impingement, separation etc.). Updated onboard F-15 based system was used to visualize supersonic boundary layer transition test article. (Tollmien-Schlichting and cross-flow dominant flow fields). Digital Recording improves image quality and analysis capability. (Allows accurate quantitative (temperature) measurements, Greater enhancement through image processing allows analysis of smaller scale phenomena).

  15. Coupling IR Thermography and BIA to analyse body reaction after one acupuncture session

    NASA Astrophysics Data System (ADS)

    Piquemal, M.

    2013-04-01

    Coupling both thermography and bio-Impedance, some biophysical acupuncture mechanisms are statically studied on a small population of 18 subjects. Results show that a possible way of understanding acupuncture, in an electrical way, should be to consider ionic flux redistribution between vascular and extra cell compartments. This is a two steps mechanism. The first one is starting with needles insertion and the second one is lasting with more intensity after removing them from skin.

  16. Transmission thermography for inspecting the busbar insulation layer in thermonuclear experimental reactor

    NASA Astrophysics Data System (ADS)

    Chen, Dapeng; Zhang, Guang; Zhang, Xiaolong; Zeng, Zhi

    2014-11-01

    In Thermonuclear Experimental Reactor, Superconducting Busbar is used for current transmission between magnet coils and current leads. The work temperature of the Busbar is about 4K because of liquid helium via inside. The large temperature grad from 300K to 4K could lead to the defects and damages occur on the insulation layer, which is made of glass fiber and polyimide and has a big different thermal expansion coefficient compared with the metal inner cylinder. This paper aims at developing an infrared transmission non-destructive evaluation (NDE) method for inspecting the insulation layer of Superconducting Busbar; theoretical model of transient heat conduction under a continuous inner heat source for cylindrical structure is described in the paper; a Busbar specimen which is designed with three delamination defects of different depths is heated inside by pouring hot water and monitored by an infrared detector located outside. Results demonstrate excellent detection performance for delamination defects in the insulation layer by using transmission thermography, all of the three defects of different depths can be visualized clearly in the thermal images, and the deeper defect has a better signal contrast, which is also shown in the temperature difference between defects and sound area vs. time curves. The results of light pulse thermography is also shown as a comparison, and it is found that the thermal images obtained by the transmission thermography has a much better signal contrast than that of the pulse thermography. In order to verify the experiments, finite element method is applied to simulate the heat conduction in the Busbar under the continuous inside heating, and it is found that the simulated temperature vs. time and simulated temperature difference vs. time curves are basically coincident with the experimental results. In addition, the possibility of in-service inspection for Busbar insulation layer in ITER item is discussed.

  17. Study on flaw detectability of NDT induction thermography technique for laminated CFRP composites

    NASA Astrophysics Data System (ADS)

    Kien Bui, Huu; Wasselynck, Guillaume; Trichet, Didier; Berthiau, Gérard

    2016-01-01

    Using a 3D finite elements simulation tool, a study on the flaw detection capacity of the non destructive testing (NDT) induction thermography (IT) technique for laminated carbon fiber reinforced polymers (CFRP) composites is presented. Delamination and fiber rupture flaw occurring at the elementary-ply scale are considered. In order to reduce the impact of measurement noise on the flaw detectability, several signal processing techniques are proposed. Contribution to the topical issue "Numelec 2015 - Elected submissions", edited by Adel Razek

  18. Application of infrared thermography to the interpretation of tests in an icing wind tunnel

    NASA Astrophysics Data System (ADS)

    Henry, R.; Guffond, D.

    Wall temperature measurements were obtained in an icing wind tunnel using infrared thermography in order to validate models for the simulation of electrothermal deicers intended for helicopter blades. The measurement procedure involves adjusting the camera for the temperature range considered, determining the directional emissivity of the profile surface and of the ice, and using Mie theory to determine the atmospheric transmission factor. The present results demonstrate the importance of taking the phase change of the ice into account in deicer modeling.

  19. Neonatal infrared thermography imaging: Analysis of heat flux during different clinical scenarios

    NASA Astrophysics Data System (ADS)

    Abbas, Abbas K.; Heimann, Konrad; Blazek, Vladimir; Orlikowsky, Thorsten; Leonhardt, Steffen

    2012-11-01

    IntroductionAn accurate skin temperature measurement of Neonatal Infrared Thermography (NIRT) imaging requires an appropriate calibration process for compensation of external effects (e.g. variation of environmental temperature, variable air velocity or humidity). Although modern infrared cameras can perform such calibration, an additional compensation is required for highly accurate thermography. This compensation which corrects any temperature drift should occur during the NIRT imaging process. We introduce a compensation technique which is based on modeling the physical interactions within the measurement scene and derived the detected temperature signal of the object. Materials and methodsIn this work such compensation was performed for different NIRT imaging application in neonatology (e.g. convective incubators, kangaroo mother care (KMC), and an open radiant warmer). The spatially distributed temperatures of 12 preterm infants (average gestation age 31 weeks) were measured under these different infant care arrangements (i.e. closed care system like a convective incubator, and open care system like kangaroo mother care, and open radiant warmer). ResultsAs errors in measurement of temperature were anticipated, a novel compensation method derived from infrared thermography of the neonate's skin was developed. Moreover, the differences in temperature recording for the 12 preterm infants varied from subject to subject. This variation could be arising from individual experimental setting applied to the same region of interest over the neonate's body. The experimental results for the model-based corrections is verified over the selected patient group. ConclusionThe proposed technique relies on applying model-based correction to the measured temperature and reducing extraneous errors during NIRT. This application specific method is based on different heat flux compartments present in neonatal thermography scene. Furthermore, these results are considered to be

  20. Early events in plant hypersensitive response leaves revealed by IR thermography

    NASA Astrophysics Data System (ADS)

    Boccara, Martine; Boue, Christine; De Paepe, Rosine; Boccara, Albert C.

    2001-10-01

    Infrared thermography is used to reveal the establishment of Erwinia amylovora harpin-induced hypersensitive response (HR) in Nicotiana sylvestris leaves. We observed a decrease in temperature (1-2 degree(s)C) in the harpin infiltrated zone, correlated with an increase in stomatal opening, strongly suggesting that the temperature decrease is due to higher transpiration rate. IRT experiments were conducted in a laboratory environment and could be widely applied for genotype screening and monitoring drug effects.

  1. A combined approach for using thermography for the detection of diabetes mellitus

    NASA Astrophysics Data System (ADS)

    Berry, Bob

    2014-05-01

    This paper presents work done to develop an early diagnosis and monitoring method-encompassing thermography for the detection of Diabetes Mellitus. The early detection method involves fusion of images from infrared cameras, ultrasound devices, a 3D camera and a dermatascope. The project is to develop a novel system that could be easily used by physicians to allow for early intervention, and the paper highlights the approach taken by the Skindetector project.

  2. Infrared dermal thermography on diabetic feet soles to predict ulcerations: a case study

    NASA Astrophysics Data System (ADS)

    Liu, Chanjuan; van der Heijden, Ferdi; Klein, Marvin E.; van Baal, Jeff G.; Bus, Sicco A.; van Netten, Jaap J.

    2013-03-01

    Diabetic foot ulceration is a major complication for patients with diabetes mellitus. If not adequately treated, these ulcers may lead to foot infection, and ultimately to lower extremity amputation, which imposes a major burden to society and great loss in health-related quality of life for patients. Early identification and subsequent preventive treatment have proven useful to limit the incidence of foot ulcers and lower extremity amputation. Thus, the development of new diagnosis tools has become an attractive option. The ultimate objective of our project is to develop an intelligent telemedicine monitoring system for frequent examination on patients' feet, to timely detect pre-signs of ulceration. Inflammation in diabetic feet can be an early and predictive warning sign for ulceration, and temperature has been proven to be a vicarious marker for inflammation. Studies have indicated that infrared dermal thermography of foot soles can be one of the important parameters for assessing the risk of diabetic foot ulceration. This paper covers the feasibility study of using an infrared camera, FLIR SC305, in our setup, to acquire the spatial thermal distribution on the feet soles. With the obtained thermal images, automated detection through image analysis was performed to identify the abnormal increased/decreased temperature and assess the risk for ulceration. The thermography for feet soles of patients with diagnosed diabetic foot complications were acquired before the ordinary foot examinations. Assessment from clinicians and thermography were compared and follow-up measurements were performed to investigate the prediction. A preliminary case study will be presented, indicating that dermal thermography in our proposed setup can be a screening modality to timely detect pre-signs of ulceration.

  3. Artificial disbonds for calibration of transient thermography inspection of thermal barrier coating systems

    NASA Astrophysics Data System (ADS)

    Ptaszek, Grzegorz; Cawley, Peter; Almond, Darryl; Pickering, Simon

    2012-05-01

    Transient thermography is commonly used for the detection of disbonds in thermal barrier coatings (TBC). As for other NDT techniques, reference test specimens are required for calibration, but unfortunately, real disbonds are very difficult to use because it is difficult to control their size, and larger ones tend to spall. Flat bottomed holes are commonly used, but these over-estimate the thermal contrast obtained for a defect of a given diameter. This paper quantifies the difference, and proposes an artificial disbond.

  4. Acoustic Emission Analysis of Damage Progression in Thermal Barrier Coatings Under Thermal Cyclic Conditions

    NASA Technical Reports Server (NTRS)

    Appleby, Matthew; Zhu, Dongming; Morscher, Gregory

    2015-01-01

    Damage evolution of electron beam-physical vapor deposited (EBVD-PVD) ZrO2-7 wt.% Y2O3 thermal barrier coatings (TBCs) under thermal cyclic conditions was monitored using an acoustic emission (AE) technique. The coatings were heated using a laser heat flux technique that yields a high reproducibility in thermal loading. Along with AE, real-time thermal conductivity measurements were also taken using infrared thermography. Tests were performed on samples with induced stress concentrations, as well as calcium-magnesium-alumino-silicate (CMAS) exposure, for comparison of damage mechanisms and AE response to the baseline (as-produced) coating. Analysis of acoustic waveforms was used to investigate damage development by comparing when events occurred, AE event frequency, energy content and location. The test results have shown that AE accumulation correlates well with thermal conductivity changes and that AE waveform analysis could be a valuable tool for monitoring coating degradation and provide insight on specific damage mechanisms.

  5. Application of Infrared Thermography as a Diagnostic Tool of Knee Osteoarthritis

    NASA Astrophysics Data System (ADS)

    Arfaoui, Ahlem; Bouzid, Mohamed Amine; Pron, Hervé; Taiar, Redha; Polidori, Guillaume

    This paper aimed to study the feasibility of application of infrared thermography to detect osteoarthritis of the knee and to compare the distribution of skin temperature between participants with osteoarthritis and those without pathology. All tests were conducted at LACM (Laboratory of Mechanical Stresses Analysis) and the gymnasium of the University of Reims Champagne Ardennes. IR thermography was performed using an IR camera. Ten participants with knee osteoarthritis and 12 reference healthy participants without OA participated in this study. Questionnaires were also used. The participants with osteoarthritis of the knee were selected on clinical examination and a series of radiographs. The level of pain was recorded by using a simple verbal scale (0-4). Infrared thermography reveals relevant disease by highlighting asymmetrical behavior in thermal color maps of both knees. Moreover, a linear evolution of skin temperature in the knee area versus time has been found whatever the participant group is in the first stage following a given effort. Results clearly show that the temperature can be regarded as a key parameter for evaluating pain. Thermal images of the knee were taken with an infrared camera. The study shows that with the advantage of being noninvasive and easily repeatable, IRT appears to be a useful tool to detect quantifiable patterns of surface temperatures and predict the singular thermal behavior of this pathology. It also seems that this non-intrusive technique enables to detect the early clinical manifestations of knee OA.

  6. Use of high resolution digital thermography to detect Heterodera schachtii infestation in sugar beets.

    PubMed

    Schmitz, A; Kiewnick, S; Schlang, J; Sikora, R A

    2004-01-01

    Thermography is a non-destructive method used to monitor pest and disease infestations, as it is related to changes in plant water status. Surface temperature differences of the crop canopy may be an indicator of nematode infestation as the parasitation of the root system reduces evaporation of leaves. To test the potential of high resolution digital thermography to detect Heterodera schachtii infestation, experiments using increasing nematode densities and different sugar beet varieties were conducted. From June to August 2003 the crop canopy temperature was measured with a thermal infrared camera from a helicopter. A significant correlation between canopy temperature and nematode density was observed with the susceptible cultivar Monza whereas the resistant cultivar Paulina did not show any correlation. Mean temperature comparison showed significant differences between the lowest infestation level (500 eggs and larvae/100 ml soil) and the highest infestation level (>1500 eggs and larvae/100 ml soil). At the beginning of the season canopy temperature differences between healthy and nematode infested sugar beets were higher (approximately 1 degree C) compared to later assessment dates when the water supply in the soil was limited. Since low and high nematode infestation could be clearly distinguished with the susceptible cultivar by airborne thermal images, thermography might be a useful tool for monitoring sugar beet fields. PMID:15759435

  7. Infrared Thermography to Evaluate Heat Tolerance in Different Genetic Groups of Lambs

    PubMed Central

    McManus, Concepta; Bianchini, Eliandra; Paim, Tiago do Prado; de Lima, Flavia Gontijo; Braccini Neto, José; Castanheira, Marlos; Esteves, Geisa Isilda Ferreira; Cardoso, Caio Cesar; Dalcin, Vanessa Calderaro

    2015-01-01

    Heat stress is considered a limiting factor for sheep production. We used information from physiological characteristics linked to heat tolerance to determine whether infrared thermography temperatures were able to separate groups of animals and determine the most important variables in this differentiation. Forty-eight four-month-old male lambs from eight genetic groups were used. Physiological (rectal temperature–RT, heart rate–HR, respiratory rate–RR) and blood traits, infrared thermography temperatures, heat tolerance indices, body measurements, weight and carcass traits were measured. Statistical analyses included variance, correlations, factor, discrimination and regression. Observing the correlations between physiological characteristics (RT, RR and HR) with temperatures measured by infrared thermography, regions for further studies should include the mean temperature of flank, nose and rump. Results show that there are strong relationships between thermograph measurements and RR, RT and HR in lambs, which are suggested to be directly correlated with heat tolerance capacity of the different genetic groups evaluated in this study. The assessment of body surface temperature measured by the thermograph could be used as a noninvasive tool to assess heat tolerance of the animals. PMID:26193274

  8. Line scanning thermography for rapid nondestructive inspection of large scale composites

    SciTech Connect

    Chung, S.; Ley, O.; Godinez, V.; Bandos, B.

    2011-06-23

    As next generation structures are utilizing larger amounts of composite materials, a rigorous and reliable method is needed to inspect these structures in order to prevent catastrophic failure and extend service life. Current inspection methods, such as ultrasonic, generally require extended down time and man hours as they are typically carried out via point-by-point measurements. A novel Line Scanning Thermography (LST) System has been developed for the non-contact, large-scale field inspection of composite structures with faster scanning times than conventional thermography systems. LST is a patented dynamic thermography technique where the heat source and thermal camera move in tandem, which allows the continuous scan of long surfaces without the loss of resolution. The current system can inspect an area of 10 in{sup 2} per 1 second, and has a resolution of 0.05x0.03 in{sup 2}. Advanced data gathering protocols have been implemented for near-real time damage visualization and post-analysis algorithms for damage interpretation. The system has been used to successfully detect defects (delamination, dry areas) in fiber-reinforced composite sandwich panels for Navy applications, as well as impact damage in composite missile cases and armor ceramic panels.

  9. Detection of seal contamination in heat-sealed food packaging based on active infrared thermography

    NASA Astrophysics Data System (ADS)

    D'huys, Karlien; Saeys, Wouter; De Ketelaere, Bart

    2015-05-01

    In the food industry packaging is often applied to protect the product from the environment, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the material used and the closure (seal). The material is selected based on the specific needs of the food product to be wrapped. However, proper closure of the package is often harder to achieve. One problem possibly jeopardizing seal quality is the presence of food particles between the seal. Seal contamination can cause a decreased seal strength and thus an increased packaging failure risk. It can also trigger the formation of microchannels through which air and microorganisms can enter and spoil the enclosed food. Therefore, early detection and removal of seal-contaminated packages from the production chain is essential. In this work, a pulsed-type active thermography method using the heat of the sealing bars as an excitation source was studied for detecting seal contamination. The cooling profile of contaminated seals was recorded. The detection performance of four processing methods (based on a single frame, a fit of the cooling profile, pulsed phase thermography and a matched filter) was compared. High resolution digital images served as a reference to quantify contamination. The lowest detection limit (equivalent diameter of 0.63 mm) and the lowest processing time (0.42 s per sample) were obtained for the method based on a single frame. Presumably, practical limitations in the recording stage prevented the added value of active thermography to be fully reflected in this application.

  10. Application of infrared lock-in thermography for the quantitative evaluation of bruises on pears

    NASA Astrophysics Data System (ADS)

    Kim, Ghiseok; Kim, Geon-Hee; Park, Jongmin; Kim, Dae-Yong; Cho, Byoung-Kwan

    2014-03-01

    An infrared lock-in thermography technique was adjusted for the detection of early bruises on pears. This mechanical damage is usually difficult to detect in the early stage after harvested using conventional visual sorting or CCD sensor-based imaging processing methods. We measured the thermal emission signals from pears using a highly sensitive mid-infrared thermal camera. These images were post-processed using a lock-in method that utilized the periodic thermal energy input to the pear. By applying the lock-in method to infrared thermography, the detection sensitivity and signal to noise ratio were enhanced because of the phase-sensitive narrow-band filtering effect. It was also found that the phase information of thermal emission from pears provides good metrics with which to identify quantitative information about both damage size and damage depth for pears. Additionally, a photothermal model was implemented to investigate the behavior of thermal waves on pears under convective conditions. Theoretical results were compared to experimental results. These results suggested that the proposed lock-in thermography technique and resultant phase information can be used to detect mechanical damage to fruit, especially in the early stage of bruising.

  11. Infrared Thermography to Evaluate Heat Tolerance in Different Genetic Groups of Lambs.

    PubMed

    McManus, Concepta; Bianchini, Eliandra; Paim, Tiago do Prado; de Lima, Flavia Gontijo; Neto, José Braccini; Castanheira, Marlos; Esteves, Geisa Isilda Ferreira; Cardoso, Caio Cesar; Dalcin, Vanessa Calderaro

    2015-07-16

    Heat stress is considered a limiting factor for sheep production. We used information from physiological characteristics linked to heat tolerance to determine whether infrared thermography temperatures were able to separate groups of animals and determine the most important variables in this differentiation. Forty-eight four-month-old male lambs from eight genetic groups were used. Physiological (rectal temperature-RT, heart rate-HR, respiratory rate-RR) and blood traits, infrared thermography temperatures, heat tolerance indices, body measurements, weight and carcass traits were measured. Statistical analyses included variance, correlations, factor, discrimination and regression. Observing the correlations between physiological characteristics (RT, RR and HR) with temperatures measured by infrared thermography, regions for further studies should include the mean temperature of flank, nose and rump. Results show that there are strong relationships between thermograph measurements and RR, RT and HR in lambs, which are suggested to be directly correlated with heat tolerance capacity of the different genetic groups evaluated in this study. The assessment of body surface temperature measured by the thermograph could be used as a noninvasive tool to assess heat tolerance of the animals.

  12. Application of infrared thermography to structural integrity evaluation of steel bridges

    NASA Astrophysics Data System (ADS)

    Sakagami, Takahide; Izumi, Yui; Kubo, Shiro

    2010-10-01

    A new remote nondestructive evaluation technique based on thermoelastic temperature measurement by infrared thermography was developed for the evaluation of fatigue cracks propagating from welded joints in steel bridges. Fatigue cracks were detected from localized thermoelastic temperature changes at crack tips due to stress singularities generated by wheel loading from traffic on a bridge. A self-reference lock-in data-processing technique was developed to improve the signal-to-noise ratio of the thermal images obtained in the crack detection process. Thermoelastic stress analyses in the vicinity of crack tips were carried out after the crack detection process by self-reference lock-in thermography. The stress distribution under wheel loading by traffic was measured by infrared thermography. Stress intensity factors were directly evaluated from the measured stress distribution. It was found that these fracture mechanics parameters can be evaluated with reasonable accuracy by the proposed technique, enabling the assessment of structural integrity based on the evaluated fracture mechanics parameters.

  13. Implementing Recommendations of the Columbia Accident Investigation Board: Development of On-Orbit IR Thermography

    NASA Technical Reports Server (NTRS)

    Ottens, Brian P.; Parker, Bradford; Stephan, Ryan

    2005-01-01

    One of NASA's Space Shuttle Return-to-Flight (RTF) efforts has been to develop thermography for the on-orbit inspection of the Reinforced Carbon Carbon (RCC) portion of the Orbiter Wing Leading Edge (WLE). This paper addresses the capability of thermography to detect cracks in RCC by using in-plane thermal gradients that naturally occur on-orbit. Crack damage, which can result from launch debris impact, is a detection challenge for other on-orbit sensors under consideration for RTF, such as the Intensified Television Camera and Laser Dynamic Range Imager. We studied various cracks in RCC, both natural and simulated, along with material characteristics, such as emissivity uniformity, in steady-state thermography. Severity of crack, such as those likely and unlikely to cause burn through were tested, both in-air and in-vacuum, and the goal of this procedure was to assure crew and vehicle safety during reentry by identification and quantification of a damage condition while on-orbit. Expected thermal conditions are presented in typical shuttle orbits, and the expected damage signatures for each scenario are presented. Finally, through statistical signal detection, our results show that even at very low in-plane thermal gradients, we are able to detect damage at or below the threshold for fatality in the most critical sections of the WLE, with a confidence exceeding 1 in 10,000 probability of false negative.

  14. Acoustic source for generating an acoustic beam

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  15. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

    In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control.

  16. What Is an Acoustic Neuroma

    MedlinePlus

    ... Acoustic Neuroma An acoustic neuroma, also called a vestibular schwannoma, is a rare benign tumor of the ... Acoustic Neuroma? An acoustic neuroma, known as a vestibular schwannoma, is a benign (non-cancerous) growth that ...

  17. Symptoms of Acoustic Neuroma

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  18. Acoustic Neuroma Educational Video

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  19. Active and passive infrared thermography applied to the detection and characterization of hidden defects in structure

    NASA Astrophysics Data System (ADS)

    Dumoulin, Jean

    2013-04-01

    Infrared thermography for Non Destructive Testing (NDT) has encountered a wide spreading this last 2 decades, in particular thanks to emergence on the market of low cost uncooled infrared camera. So, infrared thermography is not anymore a measurement technique limited to laboratory application. It has been more and more involved in civil engineering and cultural heritage applications, but also in many other domains, as indicated by numerous papers in the literature. Nevertheless, laboratory, measurements are done as much as possible in quite ideal conditions (good atmosphere conditions, known properties of materials, etc.), while measurement on real site requires to consider the influence of not controlled environmental parameters and additional unknown thermal properties. So, dedicated protocol and additional sensors are required for measurement data correction. Furthermore, thermal excitation is required to enhance the signature of defects in materials. Post-processing of data requires to take into account the protocol used for the thermal excitation and sometimes its nature to avoid false detection. This analysis step is based on signal and image processing tool and allows to carry out the detection. Characterization of anomalies detected at the previous step can be done by additional signal processing in particular for manufactured objects. The use of thermal modelling and inverse method allows to determine properties of the defective area. The present paper will first address a review of some protocols currently in use for field measurement with passive and/or active infrared measurements. Illustrations in various experiments carried out on civil engineering structure will be shown and discussed. In a second part, different post-processing approaches will be presented and discussed. In particular, a review of the most standard processing methods like Fast Fourier Analysis, Principal Components Analysis, Polynomial Decomposition, defect characterization using

  20. Non Destructive Testing by active infrared thermography coupled with shearography under same optical heat excitation

    NASA Astrophysics Data System (ADS)

    Theroux, Louis-Daniel; Dumoulin, Jean; Maldague, Xavier

    2014-05-01

    As infrastructures are aging, the evaluation of their health is becoming crucial. To do so, numerous Non Destructive Testing (NDT) methods are available. Among them, thermal shearography and active infrared thermography represent two full field and contactless methods for surface inspection. The synchronized use of both methods presents multiples advantages. Most importantly, both NDT are based on different material properties. Thermography depend on the thermal properties and shearography on the mechanical properties. The cross-correlation of both methods result in a more accurate and exact detection of the defects. For real site application, the simultaneous use of both methods is simplified due to the fact that the excitation method (thermal) is the same. Active infrared thermography is the measure of the temperature by an infrared camera of a surface subjected to heat flux. Observation of the variation of temperature in function of time reveal the presence of defects. On the other hand, shearography is a measure of out-of-plane surface displacement. This displacement is caused by the application of a strain on the surface which (in our case) take the form of a temperature gradient inducing a thermal stress To measure the resulting out-of-plane displacement, shearography exploit the relation between the phase difference and the optical path length. The phase difference is measured by the observation of the interference between two coherent light beam projected on the surface. This interference is due to change in optical path length as the surface is deformed [1]. A series of experimentation have been conducted in laboratory with various sample of concrete reinforced with CFRP materials. Results obtained reveal that with both methods it was possible to detect defects in the gluing. An infrared lamp radiating was used as the active heat source. This is necessary if measurements with shearography are to be made during the heating process. A heating lamp in the

  1. Acoustic emission frequency discrimination

    NASA Technical Reports Server (NTRS)

    Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

    1988-01-01

    In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

  2. Research on lock-in thermography for aerospace materials of nondestructive test based on image sequence processing

    NASA Astrophysics Data System (ADS)

    Liu, Junyan; Dai, Jingmin; Wang, Yang

    2008-11-01

    IR Lock in thermography is an active thermography technology based on thermal wave signal processing, especially, it has many advantages for nondestructive test of composite materials and compound structure application and has been applied on aerospace, automotive, mechanics and electric fields. In lock in thermography, given sufficient time for periodic heating, the surface temperature will evolve periodically in a sinusoidal pattern form the transient state to the steady state. In this paper, the principle of lock in thermography is introduced and the heat transferring process is analyzed by the sinusoidal variation heating flow transferred in materials by means of FEM method. In experiment, the modulating optical stimulation is applied to sample, and image sequences are collected by Jade MWIR 550 FPA IR camera. The digital filter algorithm which is Savitzky-Golay digital smoothness filters is used to remove the effects of high frequency noise. A phase image at the frequency of periodic heating can be calculated using a Fourier transform of the periodic heating frequency in transient state for defect detection. The IR lock in thermography processing software is developed by using of visual C++ programmed based image sequence collected. The experimental results show that the developed system reached up to high level of conventional steady state Lock in method.

  3. Short-circuit current density imaging of crystalline silicon solar cells via lock-in thermography: Robustness and simplifications

    SciTech Connect

    Fertig, Fabian Greulich, Johannes; Rein, Stefan

    2014-11-14

    Spatially resolved determination of solar cell parameters is beneficial for loss analysis and optimization of conversion efficiency. One key parameter that has been challenging to access by an imaging technique on solar cell level is short-circuit current density. This work discusses the robustness of a recently suggested approach to determine short-circuit current density spatially resolved based on a series of lock-in thermography images and options for a simplified image acquisition procedure. For an accurate result, one or two emissivity-corrected illuminated lock-in thermography images and one dark lock-in thermography image have to be recorded. The dark lock-in thermography image can be omitted if local shunts are negligible. Furthermore, it is shown that omitting the correction of lock-in thermography images for local emissivity variations only leads to minor distortions for standard silicon solar cells. Hence, adequate acquisition of one image only is sufficient to generate a meaningful map of short-circuit current density. Beyond that, this work illustrates the underlying physics of the recently proposed method and demonstrates its robustness concerning varying excitation conditions and locally increased series resistance. Experimentally gained short-circuit current density images are validated for monochromatic illumination in comparison to the reference method of light-beam induced current.

  4. Tutorial on architectural acoustics

    NASA Astrophysics Data System (ADS)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  5. Using infrared thermography for the creation of a window surface temperature database to validate computer heat transfer models

    SciTech Connect

    Beck, F.A.; Griffith, B.T.; Tuerler, D.; Arasteh, D.

    1995-04-01

    IR thermography is well suited for resolving small differences in the thermal performance of highly insulating window systems. Infrared thermographic measurements made in conjunction with reference emitter techniques in a controlled and characterized laboratory setting can have an absolute accuracy of {plus_minus}0.5{degree}C. Quantitative infrared thermography requires that a number of sources of error related to measurement accuracy and test environmental conditions be quantified and minimized to the extent possible. Laboratory-based infrared thermography can be used to generate window surface temperature profile databases which can be used to direct the development of 2-D and 3-D finite element and finite difference method fenestration heat transfer simulation codes, identify their strengths and weaknesses, set research priorities, and validate finished modeling tools. Development of such a database is under way at Lawrence Berkeley Laboratory, and will be made available for public use.

  6. Study on the heat flux reconstruction with the infrared thermography for the divertor target plates in the KSTAR tokamak.

    PubMed

    Kang, C S; Lee, H H; Oh, S; Lee, S G; Wi, H M; Kim, Y S; Kim, H S

    2016-08-01

    An infrared (IR) thermography is the preferred diagnostic that can quantify heat flux by measuring the surface temperature distributions of the divertor plates. The IR thermography is successfully instrumented on Korea Superconducting Tokamak Advanced Research (KSTAR). In this study, finite volume method is considered to solve the heat conduction equations. 1D-, 2D-, and 3D models are developed and compared with various calculation algorithms, such as Duhamel's theorem and THEODOR. These comparisons show good agreement. In order to acquire more efficient and reliable calculation results, we consider two numerical analysis schemes, influence of temperature on thermal properties and image stabilization. Recently, this reconstruction code is successfully applied to the KSTAR IR thermography. PMID:27587124

  7. Study on the heat flux reconstruction with the infrared thermography for the divertor target plates in the KSTAR tokamak.

    PubMed

    Kang, C S; Lee, H H; Oh, S; Lee, S G; Wi, H M; Kim, Y S; Kim, H S

    2016-08-01

    An infrared (IR) thermography is the preferred diagnostic that can quantify heat flux by measuring the surface temperature distributions of the divertor plates. The IR thermography is successfully instrumented on Korea Superconducting Tokamak Advanced Research (KSTAR). In this study, finite volume method is considered to solve the heat conduction equations. 1D-, 2D-, and 3D models are developed and compared with various calculation algorithms, such as Duhamel's theorem and THEODOR. These comparisons show good agreement. In order to acquire more efficient and reliable calculation results, we consider two numerical analysis schemes, influence of temperature on thermal properties and image stabilization. Recently, this reconstruction code is successfully applied to the KSTAR IR thermography.

  8. Study on the heat flux reconstruction with the infrared thermography for the divertor target plates in the KSTAR tokamak

    NASA Astrophysics Data System (ADS)

    Kang, C. S.; Lee, H. H.; Oh, S.; Lee, S. G.; Wi, H. M.; Kim, Y. S.; Kim, H. S.

    2016-08-01

    An infrared (IR) thermography is the preferred diagnostic that can quantify heat flux by measuring the surface temperature distributions of the divertor plates. The IR thermography is successfully instrumented on Korea Superconducting Tokamak Advanced Research (KSTAR). In this study, finite volume method is considered to solve the heat conduction equations. 1D-, 2D-, and 3D models are developed and compared with various calculation algorithms, such as Duhamel's theorem and THEODOR. These comparisons show good agreement. In order to acquire more efficient and reliable calculation results, we consider two numerical analysis schemes, influence of temperature on thermal properties and image stabilization. Recently, this reconstruction code is successfully applied to the KSTAR IR thermography.

  9. ACOUSTICAL STANDARDS NEWS.

    PubMed

    Stremmel, Neil; Struck, Christopher J

    2016-07-01

    American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, S3/SC 1, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, animal bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes a catalog of Acoustical American National Standards. To receive a copy of the latest Standards catalog, please contact Neil Stremmel.Comments are welcomed on all material in Acoustical Standards News.This Acoustical Standards News section in JASA, as well as the National Catalog of Acoustical Standards and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org. PMID:27475185

  10. A preliminary biomechanical assessment of a polymer composite hip implant using an infrared thermography technique validated by strain gage measurements.

    PubMed

    Bougherara, Habiba; Rahim, Ehsan; Shah, Suraj; Dubov, Anton; Schemitsch, Emil H; Zdero, Rad

    2011-07-01

    With the resurgence of composite materials in orthopaedic applications, a rigorous assessment of stress is needed to predict any failure of bone-implant systems. For current biomechanics research, strain gage measurements are employed to experimentally validate finite element models, which then characterize stress in the bone and implant. Our preliminary study experimentally validates a relatively new nondestructive testing technique for orthopaedic implants. Lock-in infrared (IR) thermography validated with strain gage measurements was used to investigate the stress and strain patterns in a novel composite hip implant made of carbon fiber reinforced polyamide 12 (CF/PA12). The hip implant was instrumented with strain gages and mechanically tested using average axial cyclic forces of 840 N, 1500 N, and 2100 N with the implant at an adduction angle of 15 deg to simulate the single-legged stance phase of walking gait. Three-dimensional surface stress maps were also obtained using an IR thermography camera. Results showed almost perfect agreement of IR thermography versus strain gage data with a Pearson correlation of R(2) = 0.96 and a slope = 1.01 for the line of best fit. IR thermography detected hip implant peak stresses on the inferior-medial side just distal to the neck region of 31.14 MPa (at 840 N), 72.16 MPa (at 1500 N), and 119.86 MPa (at 2100 N). There was strong correlation between IR thermography-measured stresses and force application level at key locations on the implant along the medial (R(2) = 0.99) and lateral (R(2) = 0.83 to 0.99) surface, as well as at the peak stress point (R(2) = 0.81 to 0.97). This is the first study to experimentally validate and demonstrate the use of lock-in IR thermography to obtain three-dimensional stress fields of an orthopaedic device manufactured from a composite material.

  11. Eddy current pulsed phase thermography considering volumetric induction heating for delamination evaluation in carbon fiber reinforced polymers

    NASA Astrophysics Data System (ADS)

    Yang, Ruizhen; He, Yunze

    2015-06-01

    Anisotropy and inhomogeneity of carbon fiber reinforced polymers (CFRPs) result in that many traditional non-destructive inspection techniques are inapplicable on the delamination evaluation. This letter introduces eddy current pulsed phase thermography (ECPPT) for CFRPs evaluation considering volumetric induction heating due to small electrical conductivity, abnormal thermal wave propagation, and Fourier analysis. The proposed methods were verified through experimental studies under transmission and reflection modes. Using ECPPT, the influence of the non-uniform heating effect and carbon fiber structures can be suppressed, and then delamination detectability can be improved dramatically over eddy current pulsed thermography.

  12. The influence of swimming type on the skin-temperature maps of a competitive swimmer from infrared thermography.

    PubMed

    Zaïdi, H; Taïar, R; Fohanno, S; Polidori, G

    2007-01-01

    This work aims to study the usability of infrared thermography in swimming for the purpose of quantifying the influence of the swimming style on the cartographies of cutaneous temperatures of a swimmer. Only one subject took part in the experimental protocol, who was to accomplish a 4 x 100 m 4 medley. Thermal acquisitions followed by one period of recovery with return to thermal balance were carried out between particular strokes. IR thermography made it possible to discuss the influence of the swimming style on the distributions of cutaneous temperatures in various body zones. This process seems to be completely adaptable to the development of future statistical studies. PMID:17933104

  13. A protocol for analysing thermal stress in insects using infrared thermography.

    PubMed

    Gallego, Belén; Verdú, José R; Carrascal, Luis M; Lobo, Jorge M

    2016-02-01

    The study of insect responses to thermal stress has involved a variety of protocols and methodologies that hamper the ability to compare results between studies. For that reason, the development of a protocol to standardize thermal assays is necessary. In this sense, infrared thermography solves some of the problems allowing us to take continuous temperature measurements without handling the individuals, an important fact in cold-blooded organisms like insects. Here, we present a working protocol based on infrared thermography to estimate both cold and heat thermal stress in insects. We analyse both the change in the body temperature of individuals and their behavioural response. In addition, we used partial least squares regression for the statistical analysis of our data, a technique that solves the problem of having a large number of variables and few individuals, allowing us to work with rare or endemic species. To test our protocol, we chose two species of congeneric, narrowly distributed dung beetles that are endemic to the southeastern part of the Iberian Peninsula. With our protocol we have obtained five variables in the response to cold and twelve in the response to heat. With this methodology we discriminate between the two flightless species of Jekelius through their thermal response. In response to cold, Jekelius hernandezi showed a higher rate of cooling and reached higher temperatures of stupor and haemolymph freezing than Jekelius punctatolineatus. Both species displayed similar thermoregulation ranges before reaching lethal body temperature with heat stress. Overall, we have demonstrated that infrared thermography is a suitable method to assess insect thermal responses with a high degree of sensitivity, allowing for the discrimination between closely related species. PMID:26857985

  14. Clinical study on thermography, as modern investigation method for Candida-associated denture stomatitis.

    PubMed

    Iosif, Laura; Preoteasa, Cristina Teodora; Murariu-Măgureanu, Cătălina; Preoteasa, Elena

    2016-01-01

    Candida-associated denture stomatitis is an infectious inflammatory condition of the oral mucosa, with frequent recurrences. The aim of this study was to assess the use of infrared thermography as investigation method for Candida-associated denture stomatitis (as inflammatory disorder of the maxillary denture bearing area), by comparing disease and non-disease groups. An observational study was conducted on maxillary edentulous patients treated by acrylic dentures, with and without Candida-associated denture stomatitis. Diagnostic test methods used were clinical examination for denture stomatitis and conventional microbiological culture method for oral candidiasis. Thermography analysis of the maxillary denture bearing area was made using the ThermaCAM PM350 infrared camera (Inframetrics, Flir Systems) and ThermaGram Pro 95 software, data being acquired by usage of standard protocol of thermographic registrations. The sample included 52 patients, 21 with and 31 without Candida-associated denture stomatitis. The temperature of the maxillary mucosa corresponding to the denture bearing area was found to be statistically significantly higher in Candida-associated denture stomatitis (mean 36.20°C), compared to healthy oral mucosa (mean 34.85°C). The thermal threshold value of 35.44°C was identified as best differentiating a pathological from normal state of the maxillary mucosa corresponding to the denture bearing area. In conclusion, infrared thermography, a rapid non-invasive investigation method, has the premises to bring valuable data in inflammatory disorders of the maxillary denture bearing area, as Candida-associated denture stomatitis that may be used for screening, diagnostic or monitoring purposes.

  15. In-Field-of-View Thermal Image Calibration System for Medical Thermography Applications

    NASA Astrophysics Data System (ADS)

    Simpson, R. C.; McEvoy, H. C.; Machin, G.; Howell, K.; Naeem, M.; Plassmann, P.; Ring, F.; Campbell, P.; Song, C.; Tavener, J.; Ridley, I.

    2008-06-01

    Medical thermography has become ever more accessible to hospitals, medical research, and clinical centers with the new generation of thermal cameras, which are easier to use and lower in cost. Some diagnostic techniques using thermal cameras are now regarded as standardized, such as the cold challenge test for Raynaud’s phenomenon. The future for medical thermography appears to be improved accuracy, standardization, and establishment as a mainstream medical imaging methodology. Medical thermography standardization, quantitative measurements, image comparison, and multi-center research trials all require thermal cameras to provide a demonstrably traceable, accurate, and reliable temperature output. To this end, the National Physical Laboratory (NPL) has developed a multi-fixed-point source that serves as an in-image calibration system, thereby providing a reliable means for radiometric image validation. An in-field-of-view fixed-point validation system for thermal imaging has successfully been developed, tested, and validated at NPL and has undergone field trials at three clinical centers in the UK. The sources use the phase change plateaux of gallium zinc eutectic, gallium, and ethylene carbonate. The fixed-point sources have an estimated cavity emissivity of greater than 0.998, a plateau longevity of nominally 3 h at ambient conditions, a stability of 0.1°C, or better, over that period, a repeatability of 0.1°C or better, and an estimated temperature uncertainty of ±0.4°C ( k = 2). In this article, the source specifications and design as well as testing, validation, and field trial results are described in detail.

  16. High-resolution survey of buildings by lock-in IR thermography

    NASA Astrophysics Data System (ADS)

    Bortolin, A.; Cadelano, G.; Ferrarini, G.; Bison, P.; Peron, F.; Maldague, X.

    2013-05-01

    Applications of Infrared Thermography in buildings surveys are not limited to the identification of the temperature distribution and heat losses on building envelopes. As it is well known from NDT testing in industrial applications, active IR thermographic methods such as heating-up/cooling-down or lock-in thermography improve the results in many investigations. In civil engineering these techniques have not been used widely. Mostly, thermography is used in a quasistatic manner. This paper illustrates a new approach to achieve, by the lock-in technique, an in depth view of the structure of the wall evidencing the presence of buried elements, interfaces and cracks. The idea is to take advantage of the periodic heating and cooling of earth surface due to the alternating of day and night. The corresponding thermal wave has a period equal to 24 hours that can probe the walls of buildings with a penetration depth of the order of some centimeters. The periodic temperature signal is analysed to extract amplitude and phase. It is expected that the phase image gives the indication of inhomogeneity buried in the wall structure. As a case study, the exterior surface of Palazzo Ducale in Venice is analysed and illustrated. In addition to IR images, visible electromagnetic band is considered to evaluate the strength of the solar radiation and the geometrical distortion. Indeed, the periodicity due to the Earth rotation is only approximately of 24 hours. The passing clouds or the possibility of rainy days can superimpose other heating or cooling frequencies to the main one. The Fourier analysis of the impinging radiation on the wall is performed. The façade of Palazzo Ducale is tiled with stone of two different colours and types. A final attempt to automatically classify the stone tiles in the visible and infrared images is conducted.

  17. An active thermography approach for thermal and electrical characterization of thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Streza, M.; Longuemart, S.; Guilmeau, E.; Strzalkowski, K.; Touati, K.; Depriester, M.; Maignan, A.; Sahraoui, A. Hadj

    2016-07-01

    The enhancement of figure of merit (ZT) of thermoelectrics is becoming extremely important for an efficient conversion of thermal energy into electrical energy. In this respect, reliable measurements of thermal and electrical parameters are of paramount importance in order to characterize thermoelectric materials in terms of their efficiency. In this work, a combined theoretical-experimental active thermography approach is presented. The method consists of selecting the right sequential interdependence between the excitation frequency and the sampling rate of the infrared camera, by computing a temporal Fourier analysis of each pixel of the recorded IR image. The method is validated by using a reference sample which is then applied to a recent synthesized titanium trisulphide thermoelectric material (TiS3). By combining AC and steady-state experiments, one can obtain information on both thermal and electrical parameters of TE materials (namely thermal diffusivity, Seebeck coefficient). The thermal diffusivity and thermal conductivity of TiS3 are also measured using photothermal radiometry technique (PTR) and the resulting values of these parameters are α  =  9.7*10-7 m2 s-1 and k  =  2.2 W m-1 K, respectively. The results obtained with the two techniques are in good agreement. In the case of TE materials, the main benefit of the proposed method is related to its non-contact nature and the possibility of obtaining the electric potential and temperature at the same probes. The Seebeck coefficient obtained by active IR thermography (S  =  -554 μV K-1) is consistent with the one obtained using an ULVAC-ZEM3 system (S  =  -570 μV K-1). For a large number of users of thermographic cameras, which are not equipped with a lock-in thermography module, the present approach provides an affordable and cheaper solution.

  18. An active thermography approach for thermal and electrical characterization of thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Streza, M.; Longuemart, S.; Guilmeau, E.; Strzalkowski, K.; Touati, K.; Depriester, M.; Maignan, A.; Sahraoui, A. Hadj

    2016-07-01

    The enhancement of figure of merit (ZT) of thermoelectrics is becoming extremely important for an efficient conversion of thermal energy into electrical energy. In this respect, reliable measurements of thermal and electrical parameters are of paramount importance in order to characterize thermoelectric materials in terms of their efficiency. In this work, a combined theoretical-experimental active thermography approach is presented. The method consists of selecting the right sequential interdependence between the excitation frequency and the sampling rate of the infrared camera, by computing a temporal Fourier analysis of each pixel of the recorded IR image. The method is validated by using a reference sample which is then applied to a recent synthesized titanium trisulphide thermoelectric material (TiS3). By combining AC and steady-state experiments, one can obtain information on both thermal and electrical parameters of TE materials (namely thermal diffusivity, Seebeck coefficient). The thermal diffusivity and thermal conductivity of TiS3 are also measured using photothermal radiometry technique (PTR) and the resulting values of these parameters are α  =  9.7*10‑7 m2 s‑1 and k  =  2.2 W m‑1 K, respectively. The results obtained with the two techniques are in good agreement. In the case of TE materials, the main benefit of the proposed method is related to its non-contact nature and the possibility of obtaining the electric potential and temperature at the same probes. The Seebeck coefficient obtained by active IR thermography (S  =  ‑554 μV K‑1) is consistent with the one obtained using an ULVAC-ZEM3 system (S  =  ‑570 μV K‑1). For a large number of users of thermographic cameras, which are not equipped with a lock-in thermography module, the present approach provides an affordable and cheaper solution.

  19. AST Launch Vehicle Acoustics

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  20. Mapping soil surface macropores using infrared thermography: an exploratory laboratory study.

    PubMed

    de Lima, João L M P; Abrantes, João R C B; Silva, Valdemir P; de Lima, M Isabel P; Montenegro, Abelardo A A

    2014-01-01

    Macropores and water flow in soils and substrates are complex and are related to topics like preferential flow, nonequilibrium flow, and dual-continuum. Hence, the quantification of the number of macropores and the determination of their geometry are expected to provide a better understanding on the effects of pores on the soil's physical and hydraulic properties. This exploratory study aimed at evaluating the potential of using infrared thermography for mapping macroporosity at the soil surface and estimating the number and size of such macropores. The presented technique was applied to a small scale study (laboratory soil flume). PMID:25371915

  1. Research on defects inspection of solder balls based on eddy current pulsed thermography.

    PubMed

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-10-13

    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  2. Characterization of an Inclusion of Plastazote Located in an Academic Fresco by Photothermal Thermography

    NASA Astrophysics Data System (ADS)

    Bodnar, J. L.; Nicolas, J. L.; Mouhoubi, K.; Candore, J. C.; Detalle, V.

    2013-09-01

    The aim of this study is to approach the possibilities of stimulated infrared thermography in dimensional characterization of defects situated in mural paintings. For this purpose, it is suggested to proceed in two stages. First, an in situ longitudinal thermal-diffusivity measurement is developed. Then the characterization of the depth of the studied defect by means of an extended photothermal analysis and a comparison between theory and experiment is carried out. In this article is shown that this approach allows a good estimate of the depth of a plastazote inclusion in a partial copy of the “Saint Christophe” of the Campana collection in the Louvre Museum.

  3. Infrared thermography as a diagnostic tool to indicate sick-house-syndrome: a case-study

    NASA Astrophysics Data System (ADS)

    Ljungberg, Sven-Ake

    1996-03-01

    Every third child and many adults in Sweden have allergic reactions caused by indoor environmental problems. A lot of buildings constructed during the building-boom period of 1950 - 1990 expose the sick-house-syndrome, due to built-in moisture problems and poor ventilation performance of the building. Leaky building construction, transport of humid air condensing on thermal bridges within the construction gives rise to a humid environment, and forms a base for a microbial deterioration process of organic materials, with emissions hazardous for human health. So far there are no universal and cost efficient techniques or methods developed which could be used to reveal the sick-house-syndrome. In this paper we present the results of a case-study of the sick-house-syndrome, and an investigation concept with a combination of different techniques and methods to detect and to map underlying factors that form the base for microbial activities. The concept includes mobile and indoor thermography, functional control of ventilation systems, tracer gas techniques for measurement of air flow exchange rate in different rooms, microbial investigation of emissions, field inspections within the building construction and the building envelope, and medical investigation of the health status of the people working in the building. Mobile thermography of the exterior facades has been performed with a longwave AGEMA THV 900, respectively THV 1000 infrared system, during the period December 1994 - June 1995, at different and similar weather and radiation conditions, and with the building pressurized at one accession. Indoor thermography has been performed with a shortwave AGEMA THV 470 system, for a selection of objects/surfaces with thermal deviations, indicated in thermograms from the different mobile thermographic surveys. Functional control was performed for the ventilation systems, and air flow rates were measured using tracer gas technique for a selection of rooms with different

  4. Parameterisation of non-homogeneities in buried object detection by means of thermography

    NASA Astrophysics Data System (ADS)

    Stepanić, Josip; Malinovec, Marina; Švaić, Srećko; Krstelj, Vjera

    2004-05-01

    Landmines and their natural environment form a system of complex dynamics with variable characteristics. A manifestation of that complexity within the context of thermography-based landmines detection is excessive noise in thermograms. That has severely suppressed application of thermography in landmines detection for the purposes of humanitarian demining. (To be differentiated from military demining and demining for military operations other than war [Land Mine Detection DOD's Research Program Needs a Comprehensive Evaluation Strategy, US GAO Report, GAO-01 239, 2001; International Mine Action Standards, Chapter 4.--Glossary. Available at: < http://www.mineactionstandards.org/IMAS_archive/Final/04.10.pdf>].) The discrepancy between the existing role and the actual potential of thermography in humanitarian demining motivated systematic approach to sources of noise in thermograms of buried objects. These sources are variations in mine orientation relative to soil normal, which modify the shape of mine signature on thermograms, as well as non-homogeneities in soil and vegetation layer above the mine, which modify the overall quality of thermograms. This paper analyses the influence of variable mines, and more generally the influence of axially symmetric buried object orientation on the quality of its signature on thermograms. The following two angles have been extracted to serve as parameters describing variation in orientation: (i) θ--angle between the local vertical axis and mine symmetry axis and (ii) ψ--angle between local vertical axis and soil surface normal. Their influence is compared to the influence of (iii) d--the object depth change, which serves as control parameter. The influences are quantified and ranked within a statistically planned experiment. The analysis has proved that among the parameters listed, the most influential one is statistical interaction dψ, followed with the statistical interaction dθ. According to statistical tests, these two

  5. Reconstruction of size and depth of simulated defects in austenitic steel plate using pulsed infrared thermography

    NASA Astrophysics Data System (ADS)

    Wysocka-Fotek, Olga; Oliferuk, Wiera; Maj, Michał

    2012-07-01

    In this paper the size and depth (distance from the tested surface) of defects in austenitic steel were estimated using pulse infrared thermography. The thermal contrast calculated from the surface distribution of the temperature is dependent on both these parameters. Thus, two independent experimental methods of defect size and depth determination were proposed. The defect size was estimated on the basis of surface distribution of the time derivative of the temperature, whereas the defect depth was assessed from the dependence of surface thermal contrast vs. cooling time.

  6. Research on defects inspection of solder balls based on eddy current pulsed thermography.

    PubMed

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-01-01

    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique. PMID:26473871

  7. Correlation Study Of Diffenrential Skin Temperatures (DST) For Ovulation Detection Using Infra-Red Thermography

    NASA Astrophysics Data System (ADS)

    Rao, K. H. S.; Shah, A. v.; Ruedi, B.

    1982-11-01

    The importance of ovulation time detection in the Practice of Natural Birth Control (NBC) as a contraceptive tool, and for natural/artificial insemination among women having the problem of in-fertility, is well known. The simple Basal Body Temperature (BBT) method of ovulation detection is so far unreliable. A newly proposed Differential Skin Temperature (DST) method may help minimize disturbing physiological effects and improve reliability. This paper explains preliminary results of a detailed correlative study on the DST method, using Infra-Red Thermography (IRT) imaging, and computer analysis techniques. Results obtained with five healthy, normally menstruating women volunteers will be given.

  8. Advanced techniques in IR thermography as a tool for the pest management professional

    NASA Astrophysics Data System (ADS)

    Grossman, Jon L.

    2006-04-01

    Within the past five years, the Pest Management industry has become aware that IR thermography can aid in the detection of pest infestations and locate other conditions that are within the purview of the industry. This paper will review the applications that can be utilized by the pest management professional and discuss the advanced techniques that may be required in conjunction with thermal imaging to locate insect and other pest infestations, moisture within structures, the verification of data and the special challenges associated with the inspection process.

  9. Identification of Impact Damage in Composite Laminates through Integrated Pulsed Phase Thermography and Embedded Thermal Sensors

    NASA Astrophysics Data System (ADS)

    Pawar, Sachin Sampatrao

    This dissertation develops a methodology to identify impact damage in aerospace composite laminates using integrated pulsed phase thermography and fiber Bragg grating (FBG) sensors. Initially, a two-dimensional woven, carbon fiber epoxy laminate is used to calibrate the defect depth with blind frequency for the particular material system using pulsed phase thermography (PPT). The calibration specimen contains simulated defects in the form of polymer foam inclusions. The calibrated depth vs. blind frequency relation is then applied to specimens with barely visible impact damage due to low velocity impacts. The results demonstrate that the use of the polymer insert simulated defects, in contrast to drilled holes or inserts with higher thermal contrast, provides thermal phase shifts similar to that observed in the impacted specimens. Despite the differences between the simulated and impact damage (e.g. the irregular boundaries and thin nature of the delaminations), the minimum depth of delamination from the impacted surface and the extent of damage on the rear surface of the specimen calculated from the PPT images are shown to correspond well with those of visual observations. The next group of laminated composite specimens are fabricated with embedded FBG sensors to test the ability of the combined inspection method using pulsed phase thermography and FBG sensors to identify impact damage severity. Initially three sets of specimens containing a single FBG sensor at the mid-plane, along with data from previous studies, are used to optimize the distance of low velocity impact damage from the FBG sensor and also to optimize the FBG interrogator data acquisition rate. The results from these specimens show a wide scatter in the FBG sensor temperature measurements during cooling. Also, due to its low conductivity, specimen took long time to cool, increasing the inspection time. Therefore for the final specimen the FBG sensor data acquisition is performed in the heating

  10. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    PubMed Central

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-01-01

    In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT). Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique. PMID:26473871

  11. An Overview of Recent Application of Medical Infrared Thermography in Sports Medicine in Austria

    PubMed Central

    Hildebrandt, Carolin; Raschner, Christian; Ammer, Kurt

    2010-01-01

    Medical infrared thermography (MIT) is used for analyzing physiological functions related to skin temperature. Technological advances have made MIT a reliable medical measurement tool. This paper provides an overview of MIT’s technical requirements and usefulness in sports medicine, with a special focus on overuse and traumatic knee injuries. Case studies are used to illustrate the clinical applicability and limitations of MIT. It is concluded that MIT is a non-invasive, non-radiating, low cost detection tool which should be applied for pre-scanning athletes in sports medicine. PMID:22399901

  12. Thermoelastic Analysis of a Vibrating TiB/Ti Cantilever Beam Using Differential Thermography

    SciTech Connect

    Byrd, Larry; Wyen, Travis; Byrd, Alex

    2008-02-15

    Differential thermography has been used to detect the fluctuating temperatures due the thermoelastic effect for a number of years. This paper examines functionally graded TiB/Ti cantilever beams excited on an electromechanical shaker in fully reversed bending. Finite difference analysis of specimens was used to look at the effect of heat conduction, convection and the fundamental frequency on the surface temperature distribution and compared to experimental data. The thermoelastic effect was also used to detect cracking and the stress field at the tip of the fixture during fatigue.

  13. Using infrared thermography in order to compare laser and hybrid (laser+MIG) welding processes

    NASA Astrophysics Data System (ADS)

    Matteï, Simone; Grevey, Dominique; Mathieu, Alexandre; Kirchner, Laetitia

    2009-09-01

    In order to deepen the understanding of the differences between laser and laser-arc hybrid welding, comparisons were undertaken using thermography. The experiments were carried out for a T assembly of aluminium alloy plates. Modelling, based on the finite element method approach, was realized using IR temperature measurements and seam geometry. For a value of the power supply, depicted as a surface source in the hybrid case, agreement was found between simulated and measured temperatures. The arc power supply efficiency value is similar to the usually used value.

  14. Characterization of pores in high pressure die cast aluminum using active thermography and computed tomography

    NASA Astrophysics Data System (ADS)

    Maierhofer, Christiane; Myrach, Philipp; Röllig, Mathias; Jonietz, Florian; Illerhaus, Bernhard; Meinel, Dietmar; Richter, Uwe; Miksche, Ronald

    2016-02-01

    Larger high pressure die castings (HPDC) and decreasing wall thicknesses are raising the issue of casting defects like pores in aluminum structures. Properties of components are often strongly influenced by inner porosity. As these products are being established more and more in lightweight construction (e.g. automotive and other transport areas), non-destructive testing methods, which can be applied fast and on-site, are required for quality assurance. In this contribution, the application of active thermography for the direct detection of larger pores is demonstrated. The analysis of limits and accuracy of the method are completed by numerical simulation and the method is validated using computed tomography.

  15. Photothermal Thermography Applied to the Non-destructive Testing of Different Types of Works of Art

    NASA Astrophysics Data System (ADS)

    Bodnar, J. L.; Mouhoubi, K.; Szatanik-Perrier, G.; Vallet, J. M.; Detalle, V.

    2012-11-01

    In this article, various cases in helping to restore works of art by stimulated infrared thermography are presented. First, the method allows detecting old restorations found on a mural painting in the French senate. Then, it is demonstrated how the photothermal method enables determination of the underlying structure of the mural painting "The Apotheosis of Saint Bruno" in the Charterhouse of Villeneuve-lez-Avignon. Finally, the method allows locating separate canvas paintings on "Avenant de l'aurore" in the "Luxembourg" French Senate building.

  16. Stimulated infrared thermography applied to thermophysical characterization of cultural heritage mural paintings

    NASA Astrophysics Data System (ADS)

    Bodnar, Jean-Luc; Nicolas, Jean-Louis; Mouhoubi, Kamel; Detalle, Vincent

    2012-11-01

    The purpose of this paper is to approach stimulated infrared thermography possibilities in terms of measuring longitudinal thermal diffusivity of mural paintings in situ. The measuring method principle is first submitted. It is based on temporal analysis of changes in the characteristic radius beams of spatial profiles of the photothermal signal, measured on the spot of the laser excitation. The feasibility of the method is demonstrated, thanks to a series of simulations. Lastly, the method enables to correctly estimate longitudinal thermal diffusivity in a test sample, and further in a fragment copy of "Saint Christophe" belonging to the Campana collection in the Louvre.

  17. Thermography Inspection for Early Detection of Composite Damage in Structures During Fatigue Loading

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Burke, Eric R.; Parker, F. Raymond; Seebo, Jeffrey P.; Wright, Christopher W.; Bly, James B.

    2012-01-01

    Advanced composite structures are commonly tested under controlled loading. Understanding the initiation and progression of composite damage under load is critical for validating design concepts and structural analysis tools. Thermal nondestructive evaluation (NDE) is used to detect and characterize damage in composite structures during fatigue loading. A difference image processing algorithm is demonstrated to enhance damage detection and characterization by removing thermal variations not associated with defects. In addition, a one-dimensional multilayered thermal model is used to characterize damage. Lastly, the thermography results are compared to other inspections such as non-immersion ultrasonic inspections and computed tomography X-ray.

  18. New applications of liquid-crystal thermography in rotating turbomachinery heat transfer research

    NASA Technical Reports Server (NTRS)

    Blair, M. F.; Wagner, J. H.; Steuber, G. D.

    1991-01-01

    Two new liquid-crystal thermography techniques developed for use in rotating heat transfer experiments are described. In one experiment steady-state heat transfer data were obtained on the exterior surface of rotating turbine airfoil models. In the second study a transient technique was employed to obtain interior-surface heat transfer data in a rotating turbine blade coolant passage model. Sample data are presented in the form of photographs of the liquid-crystal temperature patterns and as contour maps and distributions of heat transfer on the rotor and coolant passage surfaces.

  19. Acoustic Translation of an Acoustically Levitated Sample

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Allen, J. L.

    1986-01-01

    Acoustic-levitation apparatus uses only one acoustic mode to move sample from one region of chamber to another. Sample heated and cooled quickly by translation between hot and cold regions of levitation chamber. Levitated sample is raised into furnace region by raising plunger. Frequency of sound produced by transducers adjusted by feedback system to maintain (102) resonant mode, which levitates sample midway between transducers and plunger regardless of plunger position.

  20. Liquid Helium Acoustic Microscope.

    NASA Astrophysics Data System (ADS)

    Steer, Andrew Paul

    Available from UMI in association with The British Library. In an acoustic microscope, images are generated by monitoring the intensity of the ultrasonic reflection, or echo, from the surface of a sample. In order to achieve this a pulse of acoustic energy is produced by the excitation of a thin film transducer. The pulse thus generated propagates through a crystal and is incident upon the acoustic lens surface, which is the boundary between the crystal and an acoustic coupling liquid. The acoustic lens is a converging element, and brings the ultrasonic beam to a focus within the liquid. A sample, placed at the focus, can act as a reflector, and the returned pulse then contains information regarding the acoustic reflectivity of this specimen. Acoustic pulses are repeatedly launched and detected while the acoustic lens is scanned over the surface of the sample. In this manner an acoustic image is constructed. Acoustic losses in room temperature liquid coupling media represent a considerable source of difficulty in the recovery of acoustic echo signals. At the frequencies of operation required in a microscope which is capable of high resolution, the ultrasonic attenuation is not only large but increases with the square of frequency. In superfluid liquid helium at temperatures below 0.1 K, however, the ultrasonic attenuation becomes negligible. Furthermore, the low sound velocity in liquid helium results in an increase in resolution, since the acoustic wavelength is proportional to velocity. A liquid helium acoustic microscope has been designed and constructed. Details of the various possible detection methods are given, and comparisons are made between them. Measurements of the performance of the system that was adopted are reported. The development of a cooled preamplifier is also described. The variation of reflected signal with object distance has been measured and compared with theoretical predictions. This variation is important in the analysis of acoustic

  1. Nonlinear Acoustics in Fluids

    NASA Astrophysics Data System (ADS)

    Lauterborn, Werner; Kurz, Thomas; Akhatov, Iskander

    At high sound intensities or long propagation distances at in fluids sufficiently low damping acoustic phenomena become nonlinear. This chapter focuses on nonlinear acoustic wave properties in gases and liquids. The origin of nonlinearity, equations of state, simple nonlinear waves, nonlinear acoustic wave equations, shock-wave formation, and interaction of waves are presented and discussed. Tables are given for the nonlinearity parameter B/A for water and a range of organic liquids, liquid metals and gases. Acoustic cavitation with its nonlinear bubble oscillations, pattern formation and sonoluminescence (light from sound) are modern examples of nonlinear acoustics. The language of nonlinear dynamics needed for understanding chaotic dynamics and acoustic chaotic systems is introduced.

  2. Comparative study on submillimeter flaws in stitched T-joint carbon fiber reinforced polymer by infrared thermography, microcomputed tomography, ultrasonic c-scan and microscopic inspection

    NASA Astrophysics Data System (ADS)

    Zhang, Hai; Hassler, Ulf; Genest, Marc; Fernandes, Henrique; Robitaille, Francois; Ibarra-Castanedo, Clemente; Joncas, Simon; Maldague, Xavier

    2015-10-01

    Stitching is used to reduce dry-core (incomplete infusion of T-joint core) and reinforce T-joint structure. However, it may cause new types of flaws, especially submillimeter flaws. Microscopic inspection, ultrasonic c-scan, pulsed thermography, vibrothermography, and laser spot thermography are used to investigate the internal flaws in a stitched T-joint carbon fiber-reinforced polymer (CFRP) matrix composites. Then, a new microlaser line thermography is proposed. Microcomputed tomography (microCT) is used to validate the infrared results. A comparison between microlaser line thermography and microCT is performed. It was concluded that microlaser line thermography can detect the internal submillimeter defects. However, the depth and size of the defects can affect the detection results. The microporosities with a diameter of less than 54 μm are not detected in the microlaser line thermography results. Microlaser line thermography can detect the microporosity (a diameter of 0.162 mm) from a depth of 90 μm. However, it cannot detect the internal microporosity (a diameter of 0.216 mm) from a depth of 0.18 mm. The potential causes are given. Finally, a comparative study is conducted.

  3. Acoustic Levitator Maintains Resonance

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Gaspar, M. S.

    1986-01-01

    Transducer loading characteristics allow resonance tracked at high temperature. Acoustic-levitation chamber length automatically adjusted to maintain resonance at constant acoustic frequency as temperature changes. Developed for containerless processing of materials at high temperatures, system does not rely on microphones as resonance sensors, since microphones are difficult to fabricate for use at temperatures above 500 degrees C. Instead, system uses acoustic transducer itself as sensor.

  4. Acoustic dispersive prism

    PubMed Central

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  5. Localized acoustic surface modes

    NASA Astrophysics Data System (ADS)

    Farhat, Mohamed; Chen, Pai-Yen; Bağcı, Hakan

    2016-04-01

    We introduce the concept of localized acoustic surface modes. We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  6. Low frequency acoustic microscope

    DOEpatents

    Khuri-Yakub, Butrus T.

    1986-11-04

    A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

  7. Clinical applications of dynamic infrared thermography in plastic surgery: a systematic review

    PubMed Central

    John, Hannah Eliza; Niumsawatt, Vachara; Whitaker, Iain S.

    2016-01-01

    Background Infrared thermography (IRT) has become an increasingly utilized adjunct to more expensive and/or invasive investigations in a range of surgical fields, no more so than in plastic surgery. The combination of functional assessment, flow characteristics and anatomical localization has led to increasing applications of this technology. This article aims to perform a systematic review of the clinical applications of IRT in plastic surgery. Methods A systematic literature search using the keywords ‘IRT’ and ‘dynamic infrared thermography (DIRT)’ has been accomplished. A total of 147 papers were extracted from various medical databases, of which 34 articles were subjected to a full read by two independent reviewers, to ensure the papers satisfied the inclusion and exclusion criteria. Studies focusing on the use of IRT in breast cancer diagnosis were excluded. Results A systematic review of 29 publications demonstrated the clinical applications of IRT in plastic surgery today. They include preoperative planning of perforators for free flaps, post operative monitoring of free flaps, use of IRT as an adjunct in burns depth analysis, in assessment of response to treatment in hemangioma and as a diagnostic test for cutaneous melanoma and carpal tunnel syndrome (CTS). Conclusions Modern infrared imaging technology with improved standardization protocols is now a credible, useful non-invasive tool in clinical practice. PMID:27047781

  8. Inspection of disbonds in multilayer dissimilar metal structure using lock-in thermography.

    PubMed

    Zhou, Zhenggan; Zhao, Hanxue; Sun, Guangkai; He, Pengfei; Fan, Jin; Li, Gen

    2016-06-01

    This paper reports the characterization of disbonds between a steel plate and a lead plate on the surface of the lead using lock-in thermography. Based on the photothermal model, the excitation frequency of the bonding specimen with the steel plate and the lead plate is optimized. A lock-in thermography testing system is established to inspect the specimen. The Fourier transform method is used to process the infrared image sequences. To improve the signal-to-noise ratio (SNR), a fuzzy c-means (FCM) algorithm is used to process the phase matrix. The influence of number of clusters on the processing results is researched, and the optimal value of clusters number is obtained. The shearing phase technique is used to evaluate the size of the disbonds quantitatively. The measurement results of the artificial disbonds in the specimen show good agreement with the actual values. The results prove that FCM is effective in enhancing the SNR of the phase image, which makes it feasible for the quantitative determination of defect size by the shearing phase technique. PMID:27411208

  9. Thermography and Sonic Anemometry to Analyze Air Heaters in Mediterranean Greenhouses

    PubMed Central

    López, Alejandro; Valera, Diego L.; Molina-Aiz, Francisco; Peña, Araceli

    2012-01-01

    The present work has developed a methodology based on thermography and sonic anemometry for studying the microclimate in Mediterranean greenhouses equipped with air heaters and polyethylene distribution ducts to distribute the warm air. Sonic anemometry allows us to identify the airflow pattern generated by the heaters and to analyze the temperature distribution inside the greenhouse, while thermography provides accurate crop temperature data. Air distribution by means of perforated polyethylene ducts at ground level, widely used in Mediterranean-type greenhouses, can generate heterogeneous temperature distributions inside the greenhouse when the system is not correctly designed. The system analyzed in this work used a polyethylene duct with a row of hot air outlet holes (all of equal diameter) that expel warm air toward the ground to avoid plant damage. We have observed that this design (the most widely used in Almería's greenhouses) produces stagnation of hot air in the highest part of the structure, reducing the heating of the crop zone. Using 88 kW heating power (146.7 W·m−2) the temperature inside the greenhouse is maintained 7.2 to 11.2 °C above the outside temperature. The crop temperature (17.6 to 19.9 °C) was maintained above the minimum recommended value of 10 °C. PMID:23202025

  10. Transient-spatial pattern mining of eddy current pulsed thermography using wavelet transform

    NASA Astrophysics Data System (ADS)

    Yang, Hailong; Gao, Bin; Tian, Guiyun; Ren, Wenwei; Woo, Wai Lok

    2014-07-01

    Eddy current pulsed thermography(ECPT) is an emerging Non-destructive testing and evaluation(NDT & E) technique, which uses hybrid eddy current and thermography NDT & E techniques that enhances the detectability from their compensation. Currently, this technique is limited by the manual selection of proper contrast frames and the issue of improving the efficiency of defect detection of complex structure samples remains a challenge. In order to select a specific frame from transient thermal image sequences to maximize the contrast of thermal variation and defect pattern from complex structure samples, an energy driven approach to compute the coefficient energy of wavelet transform is proposed which has the potential of automatically selecting both optimal transient frame and spatial scale for defect detection using ECPT. According to analysis of the variation of different frequency component and the comparison study of the detection performance of different scale and wavelets, the frame at the end of heating phase is automatically selected as an optimal transient frame for defect detection. In addition, the detection capabilities of the complex structure samples can be enhanced through proper spatial scale and wavelet selection. The proposed method has successfully been applied to low speed impact damage detection of carbon fibre reinforced polymer(CFRP) composite as well as providing the guidance to improve the detectability of ECPT technique.

  11. Detection of defects in laser powder deposition (LPD) components by pulsed laser transient thermography

    NASA Astrophysics Data System (ADS)

    Santospirito, S. P.; Słyk, Kamil; Luo, Bin; Łopatka, Rafał; Gilmour, Oliver; Rudlin, John

    2013-05-01

    Detection of defects in Laser Powder Deposition (LPD) produced components has been achieved by laser thermography. An automatic in-process NDT defect detection software system has been developed for the analysis of laser thermography to automatically detect, reliably measure and then sentence defects in individual beads of LPD components. A deposition path profile definition has been introduced so all laser powder deposition beads can be modeled, and the inspection system has been developed to automatically generate an optimized inspection plan in which sampling images follow the deposition track, and automatically control and communicate with robot-arms, the source laser and cameras to implement image acquisition. Algorithms were developed so that the defect sizes can be correctly evaluated and these have been confirmed using test samples. Individual inspection images can also be stitched together for a single bead, a layer of beads or multiple layers of beads so that defects can be mapped through the additive process. A mathematical model was built up to analyze and evaluate the movement of heat throughout the inspection bead. Inspection processes were developed and positional and temporal gradient algorithms have been used to measure the flaw sizes. Defect analysis is then performed to determine if the defect(s) can be further classified (crack, lack of fusion, porosity) and the sentencing engine then compares the most significant defect or group of defects against the acceptance criteria - independent of human decisions. Testing on manufactured defects from the EC funded INTRAPID project has successful detected and correctly sentenced all samples.

  12. Pulse thermography for quantitative nondestructive evaluation of sound, de-mineralized and re-mineralized enamel

    NASA Astrophysics Data System (ADS)

    Ando, Masatoshi; Sharp, Nathan; Adams, Douglas

    2012-04-01

    Current limitations for diagnosing mineralization state of tooth enamel can lead to improper surgical treatments. A method is investigated by which the tooth health state is characterized according to its thermal response, which is hypothesized to be sensitive to increased porosity in enamel that is caused by demineralization. Several specimens consisting of previously extracted human teeth a re prepared by exposure to Streptococcus mutans A32-2 in trypticase-soy-borth supplemented with 5% sucrose at 37°C for 3 or 6 days to de-mineralize two 1×1mm2-windows on each tooth. One of these windows is then re-mineralized with 250 or 1,100ppm-F as NaF for 10 days by pH-cyclic-model. Pulse thermography is used to measure the thermal response of these sections as well as the sound (healthy) portions of the specimen. A spatial profile of the thermal parameters of the specimens is then extracted from the thermography data and are used to compare the sound, de-mineralized, and re-mineralized areas. Results show that the thermal parameters are sensitive to the mineralization state of the tooth and that this method has the potential to accurately and quickly characterize the mineralization state of teeth, thereby allowing future dentists to make informed decisions regarding the best treatment for teeth that have experienced demineralization.

  13. Infrared thermography investigation of an evaporating sessile water droplet on heated substrates.

    PubMed

    Girard, Fabien; Antoni, Mickaël; Sefiane, Khellil

    2010-04-01

    The present study is an experimental investigation of the thermal evolution of millimeter-sized sessile water droplets deposited on heated substrates. Infrared thermography is used to record temperature profiles on the droplet interface in time as evaporation takes place. The local measurements of the interface temperature allowed us to deduce the local evaporation rate and its evolution in time. To our knowledge, this is the first time that such measurements have been performed. The deduced evaporation rate using thermography data has been validated with optical measurements. Temperature evolution is used to reveal the contact line location and transient temperature fields. Temperature differences between the apex of the droplet and the contact line are shown to decrease in time. The rate of local temperature increase at the interface is found to behave linearly with time. The slope of this linear increase turns out to be more pronounced as the substrate temperature is increased. A generalized linear trend, using dimensionless properties for the interface temperature rise, is deduced from the measurements. PMID:20199075

  14. Dynamic Infrared Thermography Study of Blood Flow Relative to Lower Limp Position

    NASA Astrophysics Data System (ADS)

    Stathopoulos, I.; Skouroliakou, K.; Michail, C.; Valais, I.

    2015-09-01

    Thermography is an established method for studying skin temperature distribution. Temperature distribution on body surface is influenced by a variety of physiological mechanisms and has been proven a reliable indicator of various physiological disorders. Blood flow is an important factor that influences body heat diffusion and skin temperature. In an attempt to validate and further elucidate thermal models characterizing the human skin, dynamic thermography of the lower limp in horizontal and vertical position was performed, using a FLIR T460 thermographic camera. Temporal variation of temperature was recorded on five distinct points of the limp. Specific points were initially cooled by the means of an ice cube and measurements of the skin temperature were obtained every 30 seconds as the skin temperature was locally reduced and afterwards restored at its initial value. The return to thermal balance followed roughly the same pattern for all points of measurement, although the heating rate was faster when the foot was in horizontal position. Thermal balance was achieved faster at the spots that were positioned on a vein passage. Our results confirm the influence of blood flow on the thermal regulation of the skin. Spots located over veins exhibit different thermal behaviour due to thermal convection through blood flow. Changing the position of the foot from vertical to horizontal, effectively affects blood perfusion as in the vertical position blood circulation is opposed by gravity.

  15. Active Thermography for the Detection of Defects in Powder Metallurgy Compacts

    SciTech Connect

    Benzerrouk, Souheil; Ludwig, Reinhold; Apelian, Diran

    2007-03-21

    Active thermography is an established NDE technique that has become the method of choice in many industrial applications which require non-contact access to the parts under test. Unfortunately, when conducting on-line infrared (IR) inspection of powder metallic compacts, complications can arise due the generally low emissivity of metals and the thermally noisy environment typically encountered in manufacturing plants. In this paper we present results of an investigation that explores the suitability of active IR imaging of powder metallurgy compacts for the detection of surface and sub-surface defects in the pre-sinter state and in an on-line manufacturing setting to ensure complete quality assurance. Additional off-line tests can be carried out for statistical quality analyses. In this research, the IR imaging of sub-surface defects is based on a transient instrumentation approach that relies on an electric control system which synchronizes and monitors the thermal response due to an electrically generated heat source. Preliminary testing reveals that this newly developed pulsed thermography system can be employed for the detection of subsurface defects in green-state parts. Practical measurements agree well with theoretical predictions. The inspection approach being developed can be used for the testing of green-state compacts as they exit the compaction press at speeds of up to 1,000 parts per hour.

  16. Observations of Ice Nucleation and Propagation in Plants Using Infrared Video Thermography.

    PubMed

    Wisniewski, M.; Lindow, S. E.; Ashworth, E. N.

    1997-02-01

    We evaluated the use of infrared (IR) video thermography to observe directly ice nucleation and propagation in plants. An imaging radiometer with an HgCdTe long-wave (8-12 [mu]m) detector was utilized to image the thermal response of plants during freezing. IR images were analyzed in real time and recorded on videotape. Information on the videotape was subsequently accessed and analyzed utilizing IR image analysis software. Freezing of water droplets as small as 0.5 [mu]L was clearly detectable with the radiometer. Additionally, a comparison of temperature tracking data collected by the radiometer with data collected with thermocouples showed close correspondence. Monitoring of an array of plant species under different freezing conditions revealed that ice nucleation and propagation are readily observable by thermal imaging. In many instances, the ice nucleation-active bacterium Pseudomonas syringae placed on test plants could be seen to initiate freezing of the whole plant. Apparent ice nucleation by intrinsic nucleators, despite the presence of ice nucleation-active bacteria, was also evident in some species. Floral bud tissues of peach (Prunus persica) could be seen to supercool below the temperature of stem tissues, and ice nucleation at the site of insertion of the thermocouple was frequently observed. Rates of propagation of ice in different tissues were also easily measured by thermal imaging. This study demonstrates that IR thermography is an excellent method for studying ice nucleation and propagation in plants.

  17. Investigation of the use of thermography for research and clinical applications in pregnant women

    NASA Astrophysics Data System (ADS)

    Topalidou, Anastasia; Downe, Soo

    2016-03-01

    Background: The possibility of using thermal imaging, as a non-invasive method, in medicine may provide potential ability of advanced imaging. Objective: The conduction of a preliminary study in healthy non-pregnant females in order to investigate the imaging ability of thermography and its implementation; and to determine hot and cold areas in order to create a "map" of temperature distribution of the abdomen and the torso. Methods: Participants were 18-45 years old non-pregnant women (n = 10), who were measured at 4 different distances. Two thermal imaging cameras and their corresponding software were used to measure abdomen, low back, left and right side of the torso. Results: There were no statistically significant differences in the mean values of the exported temperatures according the distance and the angle between the camera and the subject. The inferior part of the rectus abdominis muscle recorded the coldest zone and the umbilicus appeared as the most prominent hot spot. Conclusions: Thermography shows to be a potential non-invasive technique offering new options in the evaluation of pregnant and laboring women.

  18. Principal Components of Thermography analyses of the Silk Tomb, Petra (Jordan)

    NASA Astrophysics Data System (ADS)

    Gomez-Heras, Miguel; Alvarez de Buergo, Monica; Fort, Rafael

    2015-04-01

    This communication presents the results of an active thermography survey of the Silk Tomb, which belongs to the Royal Tombs compound in the archaeological city of Petra in Jordan. The Silk Tomb is carved in the variegated Palaeozoic Umm Ishrin sandstone and it is heavily backweathered due to surface runoff from the top of the cliff where it is carved. Moreover, the name "Silk Tomb" was given because of the colourful display of the variegated sandstone due to backweathering. A series of infrared images were taken as the façade was heated by sunlight to perform a Principal Component of Thermography analyses with IR view 1.7.5 software. This was related to indirect moisture measurements (percentage of Wood Moisture Equivalent) taken across the façade, by means of a Protimeter portable moisture meter. Results show how moisture retention is deeply controlled by lithological differences across the façade. Research funded by Geomateriales 2 S2013/MIT-2914 and CEI Moncloa (UPM, UCM, CSIC) through a PICATA contract and the equipment from RedLAbPAt Network

  19. Infrared thermography based defect detection in ferromagnetic specimens using a low frequency alternating magnetic field

    NASA Astrophysics Data System (ADS)

    Lahiri, B. B.; Bagavathiappan, S.; Soumya, C.; Mahendran, V.; Pillai, V. P. M.; Philip, John; Jayakumar, T.

    2014-05-01

    A new active infrared thermography based technique is proposed for defect detection in ferromagnetic specimens using a low frequency alternating magnetic field induced heating. The test specimens (four mild steel specimens with artificial rectangular slots of 8.0, 5.0, 3.3 and 3.0 mm depths) are magnetized using a low frequency alternating magnetic field and by using an infrared camera, the surface temperature is remotely monitored in real time. An alternating magnetic field induces an eddy current in the specimen which increases the specimen temperature due to the Joule's heating. The experimental results show a thermal contrast in the defective region that decays exponentially with the defect depth. The observed thermal contrast is attributed to the reduction in induction heating due to the leakage of magnetic flux caused by magnetic permeability gradient in the defective region. The proposed technique is suitable for rapid non-contact wide area inspection of ferromagnetic materials and offers several advantages over the conventional active thermography techniques like fast direct heating, no frequency optimization, no dependence on the surface absorption coefficient and penetration depth.

  20. Observations of Ice Nucleation and Propagation in Plants Using Infrared Video Thermography.

    PubMed

    Wisniewski, M.; Lindow, S. E.; Ashworth, E. N.

    1997-02-01

    We evaluated the use of infrared (IR) video thermography to observe directly ice nucleation and propagation in plants. An imaging radiometer with an HgCdTe long-wave (8-12 [mu]m) detector was utilized to image the thermal response of plants during freezing. IR images were analyzed in real time and recorded on videotape. Information on the videotape was subsequently accessed and analyzed utilizing IR image analysis software. Freezing of water droplets as small as 0.5 [mu]L was clearly detectable with the radiometer. Additionally, a comparison of temperature tracking data collected by the radiometer with data collected with thermocouples showed close correspondence. Monitoring of an array of plant species under different freezing conditions revealed that ice nucleation and propagation are readily observable by thermal imaging. In many instances, the ice nucleation-active bacterium Pseudomonas syringae placed on test plants could be seen to initiate freezing of the whole plant. Apparent ice nucleation by intrinsic nucleators, despite the presence of ice nucleation-active bacteria, was also evident in some species. Floral bud tissues of peach (Prunus persica) could be seen to supercool below the temperature of stem tissues, and ice nucleation at the site of insertion of the thermocouple was frequently observed. Rates of propagation of ice in different tissues were also easily measured by thermal imaging. This study demonstrates that IR thermography is an excellent method for studying ice nucleation and propagation in plants. PMID:12223611

  1. The use of infrared thermography in the evaluation of oral lesions.

    PubMed

    White, B A; Lockhart, P B; Connolly, S F; Sonis, S T

    1986-11-01

    This study was conducted to quantitate the degree of inflammation associated with oral lesions by using infrared thermography. It was reasoned that the increased vascularity associated with inflamed tissue may result in measurable increases in surface temperature. One subject with normal oral mucosa and three subjects with oral lesions of varying causes were studied with a thermal video system, using an infrared imager and microprocessor. A clinical photograph of each subject was obtained. Multiple thermograms were made in a temperature range of 30.0 C to 34.2 C at a sensitivity of 0.2 C. Photographs were taken on different occasions to determine whether the temperature readings could be duplicated and to test the accuracy of each reading. The normal surface temperature of the control subject's mucosa was significantly cooler than were the temperatures of the inflamed areas in the subjects with lesions induced by chemotherapy. The temperature of the areas of stomatitis was consistent (subject 3, mean = 33.7 C; subject 4, mean = 33.9 C). The necrotic center of a traumatic ulcer inhibited measurement of an underlying inflamed base and, thus, was equivalent to the control in temperature (subject 1 (control), mean = 31.9 C; subject 2 (necrotic lesion), mean = 31.7 C). These results suggest that infrared thermography may provide a means to quantitatively assess the degree of mucosal inflammation. PMID:3465795

  2. Detection and characterisation of delamination in PV modules by active infrared thermography

    NASA Astrophysics Data System (ADS)

    Sinha, A.; Sastry, O. S.; Gupta, R.

    2016-01-01

    The paper presents a fast and efficient method for the detection and characterisation of delamination in photovoltaic (PV) modules by using active infrared thermography approach. A discrete part of PV module was irradiated by step heating and its thermal image sequence was used to detect and analyse delamination. Different types of heating source for thermal excitation for this application have been studied. An electro-thermal model was developed to simulate the active thermography approach for the characterisation of delamination in PV module by equivalent resistance-capacitance (RC) network using a circuit simulator. This simulation approach was used to estimate the extent of delamination in the module and to determine the optimum parameters for the characterisation of delamination. Different applications based on front and backsides of heating the module were also proposed in this paper. The proposed method has the potential to be employed for the quality check of PV modules during inline production as well as for the predictive maintenance of outdoor PV plants.

  3. Numerical analysis of angular defects in bent plates using tone burst eddy-current thermography (TBET)

    NASA Astrophysics Data System (ADS)

    Libin, M. N.; Balasubramaniam, Krishnan; Maxfield, B. W.

    2013-01-01

    Tone Burst Eddy current Thermography (TBET) is a new hybrid, non-contacting, Non-Destructive Evaluation (NDT) method which employs a combination of Pulsed Eddy current Thermography (PEC) and Thermographic Non-Destructive Evaluation (TNDE). For understanding angular cracks, fundamental knowledge about the induced current density distribution in the component under test is required. Further, this information enables us to find the amount of heat produced at those locations and how it diffuses to the surface. This paper describes simulation work done for cracks set at an angle to the surface in flat and bent aluminum plates. The investigation is implemented by the simulating transient thermal distribution for 2D angular cracks via finite element package COMSOL multi-physics with AC/DC module and general heat transfer. At crack edges, induced current is seen concentrated thus indicating a localized high heating in those areas relative to other regions. A numerical study was also carried out by varying parameters like crack angle (0°, 22.5°, 45°, 67.5°) and crack length (0.6mm, 1.2mm, 1.8mm) the transient thermal distributions were compared for different plate bend angles (180°, 120°, 90°, 60°, 30°). TBET method was found well suited for the detection of service induced cracks, usually caused by either rolling contact fatigue or stress corrosion, with a high degree of sensitivity.

  4. Non-destructive testing of composite materials by means of active thermography-based tools

    NASA Astrophysics Data System (ADS)

    Lizaranzu, Miguel; Lario, Alberto; Chiminelli, Agustín; Amenabar, Ibán

    2015-07-01

    Infrared analysis tools are nowadays widely used for the non-destructive testing of components made up in composite materials, belonging to many different industrial sectors. Being a non-contact method, its capability for the inspection of large areas in short periods of time justifies the great number of works and technical studies that can be found in this field. The growing interest in the technique is also supported by the development, during recent years, of increasingly powerful equipment and data analysis tools. In order to establish a base of knowledge to assist defect identification in real components inspections, the design and manufacturing of inspection samples including controlled defects, is a frequently used strategy. This paper deals with the analysis, by means of transient active thermography, of a set of inspection patterns made out of different composite materials and configurations that can be found in the wind turbine blade manufacturing industry. The design and manufacturing of these patterns are described, including different types of representative defects, stack configurations and composite manufacturing techniques. Reference samples are then inspected by means of active thermography analysis tools and the results obtained are discussed.

  5. IR thermography for the assessment of the thermal conductivity of thermoelectric modules at intermediate temperature

    NASA Astrophysics Data System (ADS)

    Boldrini, S.; Ferrario, A.; Bison, P.; Miozzo, A.; Montagner, F.; Fabrizio, M.

    2016-05-01

    The correct measurement of the performances of thermoelectric (TE) modules for energy conversion is a mandatory task both for laboratory research and for industries engaged in TE modules development or in their integration into thermoelectric generators. A testing device oriented to the maximum flexibility, based on the heat flow meter method at the cold side of the module has been developed. The system is conceived to test TE modules (single or in cascade) with a footprint up to 60x60 mm2, from room temperature up to intermediate temperature. Modules can be tested under vacuum or inert atmosphere. Specifically, the flow meter is made of a block of material, with known thermal conductivity, in contact with the cold side of the thermoelectric module. The heat flow is finally determined by measuring the temperature profile along the heat flow path and that is obtained by IR thermography. IR thermography is also utilized to evaluate the contact resistance between the active thermoelectric elements made of ceramic materials and the ceramic layer working as heat diffuser and mechanical support. Some finite element thermal analyses of the system performed for its design are presented.

  6. [Objective assessment of facial paralysis using local binary pattern in infrared thermography].

    PubMed

    Liu, Xulong; Hong, Wenxue; Zhang, Tao; Wu, Zhenying

    2013-02-01

    Facial paralysis is a frequently-occurring disease, which causes the loss of the voluntary muscles on one side of the face due to the damages the facial nerve and results in an inability to close the eye and leads to dropping of the angle of the mouth. There have been few objective methods to quantitatively diagnose it and assess this disease for clinically treating the patients so far. The skin temperature distribution of a healthy human body exhibits a contralateral symmetry. Facial paralysis usually causes an alteration of the temperature distribution of body with the disease. This paper presents the use of the histogram distance of bilateral local binary pattern (LBP) in the facial infrared thermography to measure the asymmetry degree of facial temperature distribution for objective assessing the severity of facial paralysis. Using this new method, we performed a controlled trial to assess the facial nerve function of the healthy subjects and the patients with Bell's palsy respectively. The results showed that the mean sensitivity and specificity of this method are 0.86 and 0.89 respectively. The correlation coefficient between the asymmetry degree of facial temperature distribution and the severity of facial paralysis is an average of 0.657. Therefore, the histogram distance of local binary pattern in the facial infrared thermography is an efficient clinical indicator with respect to the diagnosis and assessment of facial paralysis.

  7. Toward understanding the complex mechanisms behind breast thermography: an overview for comprehensive numerical study

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Zhan, Wang; Loew, Murray H.

    2011-03-01

    The abnormal thermogram has been shown to be a reliable indicator of a high risk of breast cancer. Nevertheless, a major weakness of current infrared breast thermography is its poor sensitivity for deeper tumors. Numerical modeling for breast thermography provides an effective tool to investigate the complex relationships between the breast thermal behaviors and the underlying patho-physiological conditions. We have developed a set of new modeling techniques to take into account some subtle factors usually ignored in previous studies, such as gravity-induced elastic deformations of the breast, nonlinear elasticity of soft tissues, and dynamic behavior of thermograms. Conventional "forward problem" modeling cannot be used directly to improve tumor detectability, however, because the underlying tissue thermal properties are generally unknown. Therefore, we propose an "inverse problem" modeling technique that aims to estimate the tissue thermal properties from the breast surface thermogram. Our data suggest that the estimation of the tumor-induced thermal contrast can be improved significantly by using the proposed inverse problem solving techniques to provide the individual-specific thermal background, especially for deeper tumors. We expect the proposed new methods, taken together, to provide a stronger foundation for, and greater specificity and precision in, thermographic diagnosis, and treatment, of breast cancer.

  8. Using infrared thermography to evaluate the injuries of cold-stored guava.

    PubMed

    Gonçalves, Bárbara Jordana; Giarola, Tales Márcio de Oliveira; Pereira, Daniele Fernanda; Vilas Boas, Eduardo Valério de Barros; de Resende, Jaime Vilela

    2016-02-01

    This study aimed to identify using the infrared (IR) thermography data the injuries of guavas during cooling and storage at different temperatures. Three experiments were performed at three different temperatures with one storage time. The first experiment was done with static air in a refrigerator at 5 °C, the second experiment was conducted in a tunnel with forced air at 10 °C, and the third experiment was conducted in an air conditioned environment at 20 °C. Mechanical injuries caused by the impact of a pendulum were induced on guava surfaces. The surface temperatures were obtained for bruised and sound tissues during cooling and storage using an Infrared (IR) camera. With thermography, it was possible to distinguish the injured tissues of the fruits that were unaffected at temperatures of 5, 10 and 20 °C in first hours of cooling. The results suggest that the storage of guava fruits at 5 °C in static air resulted in cold-induced injury, while storage at 20 °C resulted in an altered activity pattern. The stored guava fruits were analyzed for mass loss, firmness, color, total sugars, total pectin and solubility. The parameters values were lower during the forced-air cooling and storage at 5 and 10 °C. When stored at 20 °C, there was fruit maturation that caused tissue softening, which makes the fruits more susceptible to deterioration and thermographic readings showed opposite trends.

  9. Acoustic Levitation With Less Equipment

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Jacobi, N.

    1983-01-01

    Certain chamber shapes require fewer than three acoustic drivers. Levitation at center of spherical chamber attained using only one acoustic driver. Exitation of lowest spherical mode produces asymmetric acoustic potential well.

  10. Body Functions and Structures Pertinent to Infrared Thermography-Based Access for Clients with Severe Motor Disabilities

    ERIC Educational Resources Information Center

    Memarian, Negar; Venetsanopoulos, Anastasios N.; Chau, Tom

    2011-01-01

    Infrared thermography has been recently proposed as an access technology for individuals with disabilities, but body functions and structures pertinent to its use have not been documented. Seven clients (2 adults, 5 youth) with severe disabilities and their primary caregivers participated in this study. All clients had a Gross Motor Functional…

  11. Use of thermography in the detection of heat loss from school buildings: a manual for school officials

    SciTech Connect

    Cage, B.N.; Walls, M.; Wolfe, C.

    1981-01-01

    Approaches to the assessment of thermal efficiency of a building are described. Other topics discussed are: the effectiveness of various systems, the use of thermography, cost-effectiveness considerations, and the use of this technology in the public school setting. (MHR)

  12. Real-Time Debonding Monitoring of Composite Repaired Materials via Electrical, Acoustic, and Thermographic Methods

    NASA Astrophysics Data System (ADS)

    Grammatikos, S. A.; Kordatos, E. Z.; Matikas, T. E.; Paipetis, A. S.

    2014-01-01

    The electrical properties of composite materials have been thoroughly investigated recently for the detection and monitoring of damage in carbon fiber-reinforced polymers (CFRPs) under mechanical loading. Carbon nanotubes are incorporated in the polymer matrix of CFRPs for the enhancement of their electrical properties. The electrical properties have shown to be sensitive to the damage state of the material and hence their monitoring provides the profile of their structural deterioration. The aim of the paper is the cross-validation and benchmarking of an electrical potential change monitoring (EPCM) technique against acoustic emission (AE) and lock-in thermography (LT). All techniques successfully identified damage and its propagation. Thermography was more efficient in quantifying damage and describing dynamically the debond topology, as it provided full 2D imaging of the debond in real time. EPCM was successful in providing quantitative information on debond propagation and its directionality. AE provided consistent information on damage propagation. All techniques identified three stages in the fatigue life of the interrogated coupons. The representation of the fatigue behavior as a function of life fraction, the correlation of AE data with EPCM and LT data, and most importantly the consistent behavior of all tested coupons allowed for both the direct and indirect cross-correlation of all employed methodologies, which consistently identified all aforementioned fatigue life stages.

  13. Acoustics Critical Readiness Review

    NASA Technical Reports Server (NTRS)

    Ballard, Kenny

    2010-01-01

    This presentation reviews the status of the acoustic equipment from the medical operations perspective. Included is information about the acoustic dosimeters, sound level meter, and headphones that are planned for use while on orbit. Finally there is information about on-orbit hearing assessments.

  14. Introduction to acoustic emission

    NASA Technical Reports Server (NTRS)

    Possa, G.

    1983-01-01

    Typical acoustic emission signal characteristics are described and techniques which localize the signal source by processing the acoustic delay data from multiple sensors are discussed. The instrumentation, which includes sensors, amplifiers, pulse counters, a minicomputer and output devices is examined. Applications are reviewed.

  15. Virtual acoustics displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

    1991-01-01

    The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

  16. Acoustic ground impedance meter

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1984-01-01

    A method and apparatus are presented for measuring the acoustic impedance of a surface in which the surface is used to enclose one end of the chamber of a Helmholz resonator. Acoustic waves are generated in the neck of the resonator by a piston driven by a variable speed motor through a cam assembly. The acoustic waves are measured in the chamber and the frequency of the generated acoustic waves is measured by an optical device. These measurements are used to compute the compliance and conductance of the chamber and surface combined. The same procedure is followed with a calibration plate having infinite acoustic impedance enclosing the chamber of the resonator to compute the compliance and conductance of the chamber alone. Then by subtracting, the compliance and conductance for the surface is obtained.

  17. Ocean acoustic hurricane classification.

    PubMed

    Wilson, Joshua D; Makris, Nicholas C

    2006-01-01

    Theoretical and empirical evidence are combined to show that underwater acoustic sensing techniques may be valuable for measuring the wind speed and determining the destructive power of a hurricane. This is done by first developing a model for the acoustic intensity and mutual intensity in an ocean waveguide due to a hurricane and then determining the relationship between local wind speed and underwater acoustic intensity. From this it is shown that it should be feasible to accurately measure the local wind speed and classify the destructive power of a hurricane if its eye wall passes directly over a single underwater acoustic sensor. The potential advantages and disadvantages of the proposed acoustic method are weighed against those of currently employed techniques. PMID:16454274

  18. Ocean acoustic hurricane classification.

    PubMed

    Wilson, Joshua D; Makris, Nicholas C

    2006-01-01

    Theoretical and empirical evidence are combined to show that underwater acoustic sensing techniques may be valuable for measuring the wind speed and determining the destructive power of a hurricane. This is done by first developing a model for the acoustic intensity and mutual intensity in an ocean waveguide due to a hurricane and then determining the relationship between local wind speed and underwater acoustic intensity. From this it is shown that it should be feasible to accurately measure the local wind speed and classify the destructive power of a hurricane if its eye wall passes directly over a single underwater acoustic sensor. The potential advantages and disadvantages of the proposed acoustic method are weighed against those of currently employed techniques.

  19. Cochlear bionic acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  20. Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dowling, David R.; Sabra, Karim G.

    2015-01-01

    Acoustic waves carry information about their source and collect information about their environment as they propagate. This article reviews how these information-carrying and -collecting features of acoustic waves that travel through fluids can be exploited for remote sensing. In nearly all cases, modern acoustic remote sensing involves array-recorded sounds and array signal processing to recover multidimensional results. The application realm for acoustic remote sensing spans an impressive range of signal frequencies (10-2 to 107 Hz) and distances (10-2 to 107 m) and involves biomedical ultrasound imaging, nondestructive evaluation, oil and gas exploration, military systems, and Nuclear Test Ban Treaty monitoring. In the past two decades, approaches have been developed to robustly localize remote sources; remove noise and multipath distortion from recorded signals; and determine the acoustic characteristics of the environment through which the sound waves have traveled, even when the recorded sounds originate from uncooperative sources or are merely ambient noise.

  1. Acoustic suspension system

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Wang, T. G. (Inventor)

    1983-01-01

    An acoustic levitation system is described, with single acoustic source and a small reflector to stably levitate a small object while the object is processed as by coating or heating it. The system includes a concave acoustic source which has locations on opposite sides of its axis that vibrate towards and away from a focal point to generate a converging acoustic field. A small reflector is located near the focal point, and preferably slightly beyond it, to create an intense acoustic field that stably supports a small object near the reflector. The reflector is located about one-half wavelength from the focal point and is concavely curved to a radius of curvature (L) of about one-half the wavelength, to stably support an object one-quarter wavelength (N) from the reflector.

  2. Acoustic integrated extinction

    PubMed Central

    Norris, Andrew N.

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122, 3206–3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time-dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency. PMID:27547100

  3. Scrotal infrared digital thermography as a predictor of seasonal effects on sperm traits in Braford bulls

    NASA Astrophysics Data System (ADS)

    Menegassi, Silvio Renato Oliveira; Barcellos, Júlio Otavio Jardim; Dias, Eduardo Antunes; Koetz, Celso; Pereira, Gabriel Ribas; Peripolli, Vanessa; McManus, Concepta; Canozzi, Maria Eugênia Andrighetto; Lopes, Flávio Guiselli

    2015-03-01

    The aim of this study was to assess the seasonal effects of the environment on semen quality in bulls, using infrared thermography. Sperm motility (M), mass motion (MM), and vigor (VIG) were evaluated in sperm samples from 17 Bradford bulls aged approximately 24 months at the beginning of the study. Infrared thermography images and data were collected using an infrared FLIR T 300 camera and Quick Report 1.2 SP2 software to determine the temperature of the proximal and distal poles of the testis and to assess the testicular temperature gradient. The seasonal effects on physiological, seminal, and climatic variables were analyzed by the GLM ANOVA and CORR procedures using SAS®. The microclimatic factors were recorded in hourly intervals, and the daily mean temperature and mean relative humidity were calculated to determine the daily temperature-humidity index (THI) every day for 1 year. The temperature gradient (TG) variations of the testes were significantly higher in the autumn (4.5 °C), winter (4.0 °C), and spring (2.9 °C) compared to summer (0.9 °C) ( P < 0.05). Ocular globe temperatures were lower in the winter (27.6 °C) and autumn (26.8 °C) compared to summer (33.9 °C) and spring (31.1 °C) ( P < 0.05). The average MM (2.58), M (52.64), and VIG (2.70) of the semen decreased in the summer compared to other seasons ( P < 0.01). The TG was negatively correlated with THI (-0.44; P < 0.05). For the seminal variables, MaD (-0.45; P < 0.05) and TD (-0.50; P < 0.01) presented a negative correlation with TG. The TG had a positive correlation between M and VIG, which had values of 0.36 and 0.35, respectively ( P < 0.05). We have concluded that infrared thermography can be used to assess the testicular temperature gradient and its consequences on physical and quantitative aspects of sperm.

  4. Use of infrared thermography for the diagnosis and grading of sprained ankle injuries

    NASA Astrophysics Data System (ADS)

    Oliveira, João; Vardasca, Ricardo; Pimenta, Madalena; Gabriel, Joaquim; Torres, João

    2016-05-01

    Ankle joint sprains are a common medical condition estimated to be responsible for 15-25% of all musculoskeletal injuries worldwide. The pathophysiology of the lesion can represent considerable time lost to injury, as well as long-term disability in up to 60% of patients. A percentage between 10% and 20% may complicate with chronic instability of the ankle joint and disability in walking, contributing to morbidity and poor life quality. Ankle sprains can be classified as grade I, II, or III, based on the extent of damage and number of ligaments affected. The diagnostic grading is important for setting further treatment and rehabilitation, since more severe injuries carries risk of recurrence, added morbidity and decrease in life quality. The aim of this work was to evaluate the adequacy of infrared thermography as a potential complimentary diagnostic tool of the distinct lesions grades. Evaluation of different thermographic values of the ankle region (in both affected and non-affected foot) was conducted for this purpose. The principal results to be highlighted are that some of the regions, namely anterior view for non defined time after injury analysis, and anterior, frontal, posterior and anterior talofibular ligament regions and proximal calcaneofibular ligament regions in acute lesions (herein defined as less than 6 h post-traumatic event) presented consistent profiles of variation. The analyses were performed considering affected and non-affected ankles results on plotted graphics representing termographic evaluation and grading of these lesions performed using ultrasound by experimented medical radiologists. An increase in temperature values was observed when progressing from mild to severe ankle sprain injuries, with these regions presenting lower values for the affected ankle when compared to the non-affected ankle in all the analysis performed. The remaining analysed regions did not present the same variations. Statistical analysis using Kruskal

  5. Association of digital cushion thickness with sole temperature measured with the use of infrared thermography.

    PubMed

    Oikonomou, G; Trojacanec, P; Ganda, E K; Bicalho, M L S; Bicalho, R C

    2014-07-01

    The main objective of this study was to investigate the association between digital cushion thickness and sole temperature measured by infrared thermography. Data were collected from 216 lactating Holstein cows at 4 to 10d in milk (DIM). Cows were locomotion scored and sole temperature was measured after claw trimming (a minimum delay of 3 min was allowed for the hoof to cool) using an infrared thermography camera. Temperature was measured at the typical ulcer site of the lateral digit of the left hind foot. Immediately after the thermographic image was obtained, the thickness of the digital cushion was measured by ultrasonography. Rumen fluid samples were collected with a stomach tube and sample pH was measured immediately after collection. Additionally, a blood sample was obtained and used for measurements of serum concentrations of β-hydroxybutyrate (BHBA), nonesterified fatty acids (NEFA), and haptoglobin. To evaluate the associations of digital cushion thickness with sole temperature, a linear regression model was built using the GLIMMIX procedure in SAS software (SAS Institute Inc., Cary, NC). Sole temperature was the response variable, and digital cushion thickness quartiles, locomotion score group, rumen fluid pH, rumen fluid sample volume, environmental temperature, age in days, and serum levels of NEFA, BHBA, and haptoglobin were fitted in the model. Only significant variables were retained in the final model. Simple linear regression scatter plots were used to illustrate associations between sole temperature (measured by infrared thermography at the typical ulcer site) and environmental temperature and between NEFA and BHBA serum levels and haptoglobin. One-way ANOVA was used to compare rumen fluid pH for different locomotion score groups and for different digital cushion quartiles. Results from the multivariable linear regression model showed that sole temperature increased as locomotion scores increased and decreased as digital cushion thickness

  6. Damage characterization in engineering materials using a combination of optical, acoustic, and thermal techniques

    NASA Astrophysics Data System (ADS)

    Tragazikis, I. K.; Exarchos, D. A.; Dalla, P. T.; Matikas, T. E.

    2016-04-01

    This paper deals with the use of complimentary nondestructive methods for the evaluation of damage in engineering materials. The application of digital image correlation (DIC) to engineering materials is a useful tool for accurate, noncontact strain measurement. DIC is a 2D, full-field optical analysis technique based on gray-value digital images to measure deformation, vibration and strain a vast variety of materials. In addition, this technique can be applied from very small to large testing areas and can be used for various tests such as tensile, torsion and bending under static or dynamic loading. In this study, DIC results are benchmarked with other nondestructive techniques such as acoustic emission for damage localization and fracture mode evaluation, and IR thermography for stress field visualization and assessment. The combined use of these three nondestructive methods enables the characterization and classification of damage in materials and structures.

  7. Acoustic sniper localization system

    NASA Astrophysics Data System (ADS)

    Prado, Gervasio; Dhaliwal, Hardave; Martel, Philip O.

    1997-02-01

    Technologies for sniper localization have received increased attention in recent months as American forces have been deployed to various trouble spots around the world. Among the technologies considered for this task acoustics is a natural choice for various reasons. The acoustic signatures of gunshots are loud and distinctive, making them easy to detect even in high noise background environments. Acoustics provides a passive sensing technology with excellent range and non line of sight capabilities. Last but not least, an acoustic sniper location system can be built at a low cost with off the shelf components. Despite its many advantages, the performance of acoustic sensors can degrade under adverse propagation conditions. Localization accuracy, although good, is usually not accurate enough to pinpoint a sniper's location in some scenarios (for example which widow in a building or behind which tree in a grove). For these more demanding missions, the acoustic sensor can be used in conjunction with an infra red imaging system that detects the muzzle blast of the gun. The acoustic system can be used to cue the pointing system of the IR camera in the direction of the shot's source.

  8. Acoustic cooling engine

    DOEpatents

    Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1988-01-01

    An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.

  9. Acoustic mapping velocimetry

    NASA Astrophysics Data System (ADS)

    Muste, M.; Baranya, S.; Tsubaki, R.; Kim, D.; Ho, H.; Tsai, H.; Law, D.

    2016-05-01

    Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments.

  10. Calibration of acoustic transients.

    PubMed

    Burkard, Robert

    2006-05-26

    This article reviews the appropriate stimulus parameters (click duration, toneburst envelope) that should be used when eliciting auditory brainstem responses from mice. Equipment specifications required to calibrate these acoustic transients are discussed. Several methods of calibrating the level of acoustic transients are presented, including the measurement of peak equivalent sound pressure level (peSPL) and peak sound pressure level (pSPL). It is hoped that those who collect auditory brainstem response thresholds in mice will begin to use standardized methods of acoustic calibration, so that hearing thresholds across mouse strains obtained in different laboratories can more readily be compared.

  11. Acoustical heat pumping engine

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1983-08-16

    The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium.

  12. PRSEUS Acoustic Panel Fabrication

    NASA Technical Reports Server (NTRS)

    Nicolette, Velicki; Yovanof, Nicolette P.; Baraja, Jaime; Mathur, Gopal; Thrash, Patrick; Pickell, Robert

    2011-01-01

    This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration with regards to acoustic response. A PRSEUS panel was designed and fabricated and provided to NASA-LaRC for acoustic response testing in the Structural Acoustics Loads and Transmission (SALT) facility). Preliminary assessments of the sound transmission characteristics of a PRSEUS panel subjected to a representative Hybrid Wing Body (HWB) operating environment were completed for the NASA Environmentally Responsible Aviation (ERA) Program.

  13. Acoustic rotation control

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Croonquist, A. P.; Wang, T. G. (Inventor)

    1983-01-01

    A system is described for acoustically controlled rotation of a levitated object, which avoids deformation of a levitated liquid object. Acoustic waves of the same wavelength are directed along perpendicular directions across the object, and with the relative phases of the acoustic waves repeatedly switched so that one wave alternately leads and lags the other by 90 deg. The amount of torque for rotating the object, and the direction of rotation, are controlled by controlling the proportion of time one wave leads the other and selecting which wave leads the other most of the time.

  14. Acoustical heat pumping engine

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-08-16

    The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium. 2 figs.

  15. Acoustic well cleaner

    DOEpatents

    Maki, Jr., Voldi E.; Sharma, Mukul M.

    1997-01-21

    A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.

  16. Underwater acoustic omnidirectional absorber

    NASA Astrophysics Data System (ADS)

    Naify, Christina J.; Martin, Theodore P.; Layman, Christopher N.; Nicholas, Michael; Thangawng, Abel L.; Calvo, David C.; Orris, Gregory J.

    2014-02-01

    Gradient index media, which are designed by varying local element properties in given geometry, have been utilized to manipulate acoustic waves for a variety of devices. This study presents a cylindrical, two-dimensional acoustic "black hole" design that functions as an omnidirectional absorber for underwater applications. The design features a metamaterial shell that focuses acoustic energy into the shell's core. Multiple scattering theory was used to design layers of rubber cylinders with varying filling fractions to produce a linearly graded sound speed profile through the structure. Measured pressure intensity agreed with predicted results over a range of frequencies within the homogenization limit.

  17. The use of thermography in energy performance of buildings-directive (EPBD)-applications

    NASA Astrophysics Data System (ADS)

    Kauppinen, T.

    2009-05-01

    EPBD-directive has taken into the use in European Union Countries. In Finland, in connection with the directive and with harmonization of building codes, the building codes dealing with insulation and energy use has been renewed. At the first time there is a requirement of energy efficiency calculations. Energy efficiency is connected with energy labeling. Also first time there are now prerequisites for air tightness of buildings. These new challenges have created a boom of increased quality control needs in construction companies, including different verification methods. The use of thermography and air-tightness test (blower door tests) has been exploited by increasing speed. The interpretation of result will be a growing problem, even lot of work has been done e.g. in certification procedure of building thermographers. In this presentation some results of multi-storey apartment houses and other targets will be presented, and discussion about the problems which may occur in the future.

  18. Eddy Current Pulsed Thermography with Different Excitation Configurations for Metallic Material and Defect Characterization.

    PubMed

    Tian, Gui Yun; Gao, Yunlai; Li, Kongjing; Wang, Yizhe; Gao, Bin; He, Yunze

    2016-06-08

    This paper reviews recent developments of eddy current pulsed thermography (ECPT) for material characterization and nondestructive evaluation (NDE). Due to the fact that line-coil-based ECPT, with the limitation of non-uniform heating and a restricted view, is not suitable for complex geometry structures evaluation, Helmholtz coils and ferrite-yoke-based excitation configurations of ECPT are proposed and compared. Simulations and experiments of new ECPT configurations considering the multi-physical-phenomenon of hysteresis losses, stray losses, and eddy current heating in conjunction with uniform induction magnetic field have been conducted and implemented for ferromagnetic and non-ferromagnetic materials. These configurations of ECPT for metallic material and defect characterization are discussed and compared with conventional line-coil configuration. The results indicate that the proposed ECPT excitation configurations can be applied for different shapes of samples such as turbine blade edges and rail tracks.

  19. Aerial thermography from low-cost UAV for the generation of thermographic digital terrain models

    NASA Astrophysics Data System (ADS)

    Lagüela, S.; Díaz-Vilariño, L.; Roca, D.; Lorenzo, H.

    2015-03-01

    Aerial thermography is performed from a low-cost aerial vehicle, copter type, for the acquisition of data of medium-size areas, such as neighbourhoods, districts or small villages. Thermographic images are registered in a mosaic subsequently used for the generation of a thermographic digital terrain model (DTM). The thermographic DTM can be used with several purposes, from classification of land uses according to their thermal response to the evaluation of the building prints as a function of their energy performance, land and water management. In the particular case of buildings, apart from their individual evaluation and roof inspection, the availability of thermographic information on a DTM allows for the spatial contextualization of the buildings themselves and the general study of the surrounding area for the detection of global effects such as heat islands.

  20. C/C composite brake disk nondestructive evaluation by IR thermography

    NASA Astrophysics Data System (ADS)

    Chu, Tsuchin P.; Poudel, Anish; Filip, Peter

    2012-06-01

    This paper discusses the non-destructive evaluation of thick Carbon/Carbon (C/C) composite aircraft brake disks by using transient infrared thermography (IRT) approach. Thermal diffusivity measurement technique was applied to identify the subsurface anomalies in thick C/C brake disks. In addition, finite element analysis (FEA) modeling tool was used to determine the transient thermal response of the C/C disks that were subjected to flash heating. For this, series of finite element models were built and thermal responses with various thermal diffusivities subjected to different heating conditions were investigated. Experiments were conducted to verify the models by using custom built in-house IRT system and commercial turnkey system. The analysis and experimental results showed good correlation between thermal diffusivity value and anomalies within the disk. It was demonstrated that the step-heating transient thermal approach could be effectively applied to obtain the whole field thermal diffusivity value of C/C composites.

  1. Characterization of defects situated in a fresco by stimulated infrared thermography

    NASA Astrophysics Data System (ADS)

    Candoré, J. C.; Bodnar, J. L.; Detalle, V.; Grossel, P.

    2012-01-01

    The objective of this work is to approach the possibilities of stimulated infrared thermography in dimensional characterization of defects situated in mural paintings. Towards this end, we have proceeded in two stages. Initially, we have developed, with the help of a point source photothermal analysis, an in situ measurement of the longitudinal thermal diffusivity parameter. Then, we have proceeded to the characterization of the depth of the studied defect, by means of a wide photothermal analysis and of a confrontation between theory and experiment. In this article, we present these two measurement techniques and show that the approach allows a good estimation of the depth of an inclusion of plastazote in a copy of the "Saint Christophe" of the "Campana" collection of the "Louvre Museum".

  2. Contribution to the improvement of heritage mural painting non-destructive testing by stimulated infrared thermography

    NASA Astrophysics Data System (ADS)

    Bodnar, Jean-Luc; Mouhoubi, Kamel; Di Pallo, Luigi; Detalle, Vincent; Vallet, Jean-Marc; Duvaut, Thierry

    2013-10-01

    Non-destructive testing of heritage mural paintings by means of stimulated infrared thermography has now become rather efficient [1-14]. However, pigments, which form a pictorial layer, have contrasting radiative properties possibly leading to artifact detection. In this paper, attempts to alleviate this difficulty are presented. Based on the spectroscopic study of different paint layers, one can argue that, in the medium infrared field, this radiative disparity decreases significantly. Then, with similar settings, it can be shown that ceramic radiative sources allow reaching this wavelength band. Finally, on the basis of a study carried out on an academic sample and a partial copy of a fresco from the cathedral of Angers, combining ceramic heat sources with a laboratory SAMMTHIR experimental setup enables to make real headway in terms of defects' detection.

  3. Infrared thermography for process control and predictive maintenance purposes in a steel wire drawing machine

    NASA Astrophysics Data System (ADS)

    Rozlosnik, Andres E.; Lardone, Victor M.

    1999-03-01

    The industrial drawing process reduces the section of the wire rod by pulling the material through a hard die. This process generates heat by deformation and friction. The heat generated must be immediately removed after every reduction diameter step, otherwise the final quality of wire and the drawing performance will be poor. That is the reason why the improvement of the cooling efficiency in the drawing machine is of great importance. The better the cooling efficiency, the greater the wire quality and the productivity of the process will be. Nowadays, the infrared thermography control offer the possibility to analyze how the drawing aspect is affecting the cooling efficiency and how this technique allows the drawing process improvements. As you look at the capstans in the wire process control, you are doing at the same time, predictive maintenance in the machine.

  4. Irradiance-based emissivity correction in infrared thermography for electronic applications.

    PubMed

    Vellvehi, M; Perpiñà, X; Lauro, G L; Perillo, F; Jordà, X

    2011-11-01

    This work analyzes, discusses, and proposes a solution to the problem of the emissivity correction present in infrared thermography when coatings with known emissivity cannot be deposited on the inspected surface. It is shown that the conventional technique based on two reference thermal images and the linearization of the blackbody radiation dependence on temperature is not a reliable and accurate solution when compared with the coating procedure. In this scenario, a new approach based on the direct processing of the output signal of the infrared camera (which is proportional to the detected irradiance) is proposed to obtain an accurate emissivity and surrounding reflections map, perfectly compensating the thermal maps. The results obtained have been validated using a module as a test vehicle containing two thermal test chips which incorporate embedded temperature sensors.

  5. Infrared thermography and acupuncture of the lobe of the outer ear in patients with facial pain

    NASA Astrophysics Data System (ADS)

    Rossi, Ricardo; Lluesma, Eliseo G.

    2001-03-01

    We have assessed the thermal camera to complement the clinical odontology with the clinical assistance of acupuncture. Relevant cases of study were those of patients with facial pain. This work has registered the temperatures of the microsystem of the lobe of the outer ear. The recordings were made before, during and after removing the needles. Measurements of patients' temperatures were made very two minutes for 20 minutes, and a gradual increase of temperature was observed. The thermal camera allowed to register maps (thermography) that show an area affected with pain. After thermograms were performed to odontology patients treated with acupuncture, we were able to compare the temperature distribution maps and we found that they were quasi repetitive in the same zones in several patients for a specific illness. We made this technique available to different patients with lack of good irrigation on face and neck with the aim to establish patterns.

  6. Thermal runaway in polyimide at high electric field probed by infrared thermography

    NASA Astrophysics Data System (ADS)

    Diaham, Sombel; Belijar, Guillaume; Locatelli, Marie-Laure; Lebey, Thierry

    2015-03-01

    An original way for characterizing dielectrics under high electric field and high temperature based on the coupling between electric current measurements and real-time fast infrared (IR) thermography is demonstrated. Particularly, the Joule heating phenomenon at high field is quantified by 2D-temperature cartography in a polyimide (PI) film set at an initial temperature of 300 °C through IR observations of the polarized electrode. 2D-temperature cartography highlights the temperature increase with increasing the electric field. The thermal runway occurs prior to the dielectric breakdown from an electric field threshold of 140-150 V/μm. This corresponds to a dissipated volume power density between 2 and 5 mW/μm3. Such values report the limit of the electro-thermal equilibrium in PI film.

  7. A simple blackbody simulator with several possibilities and applications on thermography

    NASA Astrophysics Data System (ADS)

    dos Santos, Laerte; Lemos, Alisson Maria; Abi-Ramia, Marco Antônio

    2016-05-01

    Originally designed to make the practical examination on thermography certification1 possible, the device presented in this paper has demonstrated to be a very useful and versatile didactic tool for training centers and educational institutions, it can also be used as a low cost blackbody simulator to verify calibration of radiometers. It is a simple device with several functionalities for studying and for applications on heat transfer and radiometry, among them the interesting ability to thermally simulate the surface of real objects. On that functionality, if the device is seen by a thermographic camera, it reproduces the surface apparent temperatures of the object that it is simulating, at the same time, if it is seen by a naked eye it shows a visible image of that same surface. This functionality makes the practical study in the classroom possible, from different areas such as electrical, mechanical, medical, building, veterinary, etc.

  8. Photothermal and infrared thermography characterizations of thermal diffusion in hydroxyapatite materials

    NASA Astrophysics Data System (ADS)

    Bante-Guerra, J.; Conde-Contreras, M.; Trujillo, S.; Martinez-Torres, P.; Cruz-Jimenez, B.; Quintana, P.; Alvarado-Gil, J. J.

    2009-02-01

    Non destructive analysis of hydroxyapatite materials is an active research area mainly in the study of dental pieces and bones due to the importance these pieces have in medicine, archeology, dentistry, forensics and anthropology. Infrared thermography and photothermal techniques constitute highly valuable tools in those cases. In this work the quantitative analysis of thermal diffusion in bones is presented. The results obtained using thermographic images are compared with the ones obtained from the photothermal radiometry. Special emphasis is done in the analysis of samples with previous thermal damage. Our results show that the treatments induce changes in the physical properties of the samples. These results could be useful in the identification of the agents that induced modifications of unknown origin in hydroxyapatite structures.

  9. Thermal performance of windows by means of thermography and heat-flux meters

    NASA Astrophysics Data System (ADS)

    Kauppinen, Timo T.

    2002-03-01

    The replacement of windows is the most common renovation measure in Finland. There are also problems in new buildings especially with new thin light metal-framed windows, even though the U-value of the pane would be acceptable. The minor defects in the installation may cause IAQ-problems - because of seam leaks and thermal bridges. There is no general procedure for condition survey of windows based on measurements. In this paper a procedure for testing windows in in-situ conditions is presented based on case studies. Thermal performance of windows can be measured using thermography and supporting methods, like heat-flux measurements and air leak tests. Even though the absolute results may include interfering factors, we can compare the windows with each other (depending on the conditions) and make decisions on the quality of the installation work and the thermal performance of windows.

  10. Comparison of luminescence imaging and illuminated lock-in thermography on silicon solar cells

    NASA Astrophysics Data System (ADS)

    Kasemann, Martin; Schubert, Martin C.; The, Manuel; Köber, Mariana; Hermle, Martin; Warta, Wilhelm

    2006-11-01

    Spatially resolved electroluminescence (EL) and photoluminescence (PL) images of solar cells are compared to spatially resolved power loss images obtained by illuminated lock-in thermography (ILIT). A significant difference is shown for a solar cell with shunts, while series resistance and charge carrier recombination cause only minor differences in the images. The PL image of a solar cell with shunts appears highly blurred in the shunted region. The origin of this effect is discussed, and a circuit simulation with an appropriate solar cell model is performed. The authors conclude that the blurring of shunted regions is inherent in the method of EL/PL imaging and that ILIT is advantageous for localizing shunts.

  11. Gamma-irradiation tests of IR optical fibres for ITER thermography--a case study

    SciTech Connect

    Reichle, R.; Pocheau, C.; Jouve, M.

    2008-03-12

    In the course of the development of a concept for a spectrally resolving infrared thermography diagnostic for the ITER divertor we have tested 3 types of infrared (IR) fibres in Co{sup 60} irradiation facilities under {gamma} irradiation. The fibres were ZrF{sub 4} (and HfF{sub 4}) fibres from different manufacturers, hollow fibres (silica capillaries with internal Ag/AgJ coating) and a sapphire fibre. For the IR range, only the latter fibre type encourages to go further for neutron tests in a reactor. If one restricted the interest onto the near infrared range, high purity core silica fibres could be used. This study might be seen as a typical example of the relation between diagnostic development for a nuclear environment and irradiation experiments.

  12. Advanced ultrasound activated lockin-thermography for defect selective depth-resolved imaging

    NASA Astrophysics Data System (ADS)

    Gleiter, A.; Riegert, G.; Zweschper, Th.; Degenhardt, R.; Busse, G.

    2006-04-01

    Ultrasound activated Lockin-Thermography ("ultrasound attenuation mapping") is a defect selective NDT-technique. Its main advantage is a high probability of defect detection ("POD") since only defects produce a signal while all other features are suppressed. The mechanism involved is local sound absorption which turns a variably loaded defect into a heat source. Thermographic monitoring of elastic wave attenuation in defects was reported for the first time in 1979 by Henneke and colleagues for continuous and pulsed ultrasound injection. Later, amplitude modulated ultrasound was used to derive frequency coded phase angle images combining defect-selectivity with robustness of measurement. With mono-frequent ultrasound excitation a standing wave pattern might hide defects. With additional modulation of the ultrasound frequency such a misleading pattern can be minimized. Applications related to quality maintenance (aerospace, automotive industry) will be presented in order to illustrate the potential of frequency modulated ultrasound excitation and its applications.

  13. Eddy Current Pulsed Thermography with Different Excitation Configurations for Metallic Material and Defect Characterization.

    PubMed

    Tian, Gui Yun; Gao, Yunlai; Li, Kongjing; Wang, Yizhe; Gao, Bin; He, Yunze

    2016-01-01

    This paper reviews recent developments of eddy current pulsed thermography (ECPT) for material characterization and nondestructive evaluation (NDE). Due to the fact that line-coil-based ECPT, with the limitation of non-uniform heating and a restricted view, is not suitable for complex geometry structures evaluation, Helmholtz coils and ferrite-yoke-based excitation configurations of ECPT are proposed and compared. Simulations and experiments of new ECPT configurations considering the multi-physical-phenomenon of hysteresis losses, stray losses, and eddy current heating in conjunction with uniform induction magnetic field have been conducted and implemented for ferromagnetic and non-ferromagnetic materials. These configurations of ECPT for metallic material and defect characterization are discussed and compared with conventional line-coil configuration. The results indicate that the proposed ECPT excitation configurations can be applied for different shapes of samples such as turbine blade edges and rail tracks. PMID:27338389

  14. LATERAL HEAT FLOW INFRARED THERMOGRAPHY FOR THICKNESS INDEPENDENT DETERMINATION OF THERMAL DIFFUSIVITY IN CFRP

    SciTech Connect

    Tralshawala, Nilesh; Howard, Don; Knight, Bryon; Plotnikov, Yuri; Ringermacher, Harry

    2008-02-28

    In conventional infrared thermography, determination of thermal diffusivity requires thickness information. Recently GE has been experimenting with the use of lateral heat flow to determine thermal diffusivity without thickness information. This work builds on previous work at NASA Langley and Wayne State University but we incorporate thermal time of flight (tof) analysis rather than curve fitting to obtain quantitative information. We have developed appropriate theoretical models and a tof based data analysis framework to experimentally determine all components of thermal diffusivity from the time-temperature measurements. Initial validation was carried out using finite difference simulations. Experimental validation was done using anisotropic carbon fiber reinforced polymer (CFRP) composites. We found that in the CFRP samples used, the in-plane component of diffusivity is about eight times larger than the through-thickness component.

  15. Eddy Current Pulsed Thermography with Different Excitation Configurations for Metallic Material and Defect Characterization

    PubMed Central

    Tian, Gui Yun; Gao, Yunlai; Li, Kongjing; Wang, Yizhe; Gao, Bin; He, Yunze

    2016-01-01

    This paper reviews recent developments of eddy current pulsed thermography (ECPT) for material characterization and nondestructive evaluation (NDE). Due to the fact that line-coil-based ECPT, with the limitation of non-uniform heating and a restricted view, is not suitable for complex geometry structures evaluation, Helmholtz coils and ferrite-yoke-based excitation configurations of ECPT are proposed and compared. Simulations and experiments of new ECPT configurations considering the multi-physical-phenomenon of hysteresis losses, stray losses, and eddy current heating in conjunction with uniform induction magnetic field have been conducted and implemented for ferromagnetic and non-ferromagnetic materials. These configurations of ECPT for metallic material and defect characterization are discussed and compared with conventional line-coil configuration. The results indicate that the proposed ECPT excitation configurations can be applied for different shapes of samples such as turbine blade edges and rail tracks. PMID:27338389

  16. Recognition of wall materials through active thermography coupled with numerical simulations.

    PubMed

    Pietrarca, Francesca; Mameli, Mauro; Filippeschi, Sauro; Fantozzi, Fabio

    2016-09-01

    In the framework of historical buildings, wall thickness as well as wall constituents are not often known a priori, and active IR thermography can be exploited as a nonintrusive method for detecting what kind of material lies beneath the external plaster layer. In the present work, the wall of a historical building is subjected to a heating stimulus, and the surface temperature temporal trend is recorded by an IR camera. A hybrid numerical model is developed in order to simulate the transient thermal response of a wall made of different known materials underneath the plaster layer. When the numerical thermal contrast and the appearance time match with the experimental thermal images, the material underneath the plaster can be qualitatively identified. PMID:27607254

  17. Infrared thermography for detection of laminar-turbulent transition in low-speed wind tunnel testing

    NASA Astrophysics Data System (ADS)

    Joseph, Liselle A.; Borgoltz, Aurelien; Devenport, William

    2016-05-01

    This work presents the details of a system for experimentally identifying laminar-to-turbulent transition using infrared thermography applied to large, metal models in low-speed wind tunnel tests. Key elements of the transition detection system include infrared cameras with sensitivity in the 7.5- to 14.0-µm spectral range and a thin, insulating coat for the model. The fidelity of the system was validated through experiments on two wind-turbine blade airfoil sections tested at Reynolds numbers between Re = 1.5 × 106 and 3 × 106. Results compare well with measurements from surface pressure distributions and stethoscope observations. However, the infrared-based system provides data over a much broader range of conditions and locations on the model. This paper chronicles the design, implementation and validation of the infrared transition detection system, a subject which has not been widely detailed in the literature to date.

  18. The development of in-situ calibration method for divertor IR thermography in ITER

    SciTech Connect

    Takeuchi, M.; Sugie, T.; Ogawa, H.; Takeyama, S.; Itami, K.

    2014-08-21

    For the development of the calibration method of the emissivity in IR light on the divertor plate in ITER divertor IR thermography system, the laboratory experiments have been performed by using IR instruments. The calibration of the IR camera was performed by the plane black body in the temperature of 100–600 degC. The radiances of the tungsten heated by 280 degC were measured by the IR camera without filter (2.5–5.1 μm) and with filter (2.95 μm, 4.67 μm). The preliminary data of the scattered light of the laser of 3.34 μm that injected into the tungsten were acquired.

  19. Logarithmic analysis of eddy current thermography based on longitudinal heat conduction for subsurface defect evaluation

    NASA Astrophysics Data System (ADS)

    Yang, Ruizhen; He, Yunze

    2014-11-01

    Longitudinal heat conduction from surface to inside of solid material could be used to evaluate the subsurface defects. Considering that the skin depth of high frequency eddy current in metal is quite small, this paper proposed logarithmic analysis of eddy current thermography (ECT) to quantify the depth of subsurface defects. The proposed method was verified through numerical and experimental studies. In numerical study, ferromagnetic material and non-ferromagnetic material were both considered. Results showed that the temperature-time curve in the logarithm domain could be used to detect subsurface defects. Separation time was defined as the characteristic feature to measure the defect's depth based on their linear relationships. The thermograms reconstructed by logarithm of temperature can improve defect detectability.

  20. Non-destructive testing of works of art by stimulated infrared thermography

    NASA Astrophysics Data System (ADS)

    Candoré, J. C.; Bodnar, J. L.; Detalle, V.; Grossel, P.

    2012-02-01

    In this work, we present various examples of assistance to the restoration of works of art by stimulated infrared thermography. We show initially that the method allows the detection of delamination located in mural paintings, such as in the "Saint Christophe" of the Campana collection of the Louvre French museum. We show then that it also makes it possible to detect delaminations or galleries of worms in marquetries. We show in a third stage that it provides for the detection of detachment of grayness in stained glasses. We show in a fourth stage that it allows the visualization of shards or metal inserts located in a Greek "panathénaque" amphora of the French National museum of the Ceramics of Sevres. We show finally, that the method permits the detection of a crack located in an ovoid vase of the same French National museum of the Ceramics of Sevres.

  1. Characterization of emission microscopy and liquid crystal thermography in IC fault localization

    NASA Astrophysics Data System (ADS)

    Lau, C. K.; Sim, K. S.

    2013-05-01

    This paper characterizes two fault localization techniques - Emission Microscopy (EMMI) and Liquid Crystal Thermography (LCT) by using integrated circuit (IC) leakage failures. The majority of today's semiconductor failures do not reveal a clear visual defect on the die surface and therefore require fault localization tools to identify the fault location. Among the various fault localization tools, liquid crystal thermography and frontside emission microscopy are commonly used in most semiconductor failure analysis laboratories. Many people misunderstand that both techniques are the same and both are detecting hot spot in chip failing with short or leakage. As a result, analysts tend to use only LCT since this technique involves very simple test setup compared to EMMI. The omission of EMMI as the alternative technique in fault localization always leads to incomplete analysis when LCT fails to localize any hot spot on a failing chip. Therefore, this research was established to characterize and compare both the techniques in terms of their sensitivity in detecting the fault location in common semiconductor failures. A new method was also proposed as an alternative technique i.e. the backside LCT technique. The research observed that both techniques have successfully detected the defect locations resulted from the leakage failures. LCT wass observed more sensitive than EMMI in the frontside analysis approach. On the other hand, EMMI performed better in the backside analysis approach. LCT was more sensitive in localizing ESD defect location and EMMI was more sensitive in detecting non ESD defect location. Backside LCT was proven to work as effectively as the frontside LCT and was ready to serve as an alternative technique to the backside EMMI. The research confirmed that LCT detects heat generation and EMMI detects photon emission (recombination radiation). The analysis results also suggested that both techniques complementing each other in the IC fault localization

  2. Diagnosis of response and non-response to dry eye treatment using infrared thermography images

    NASA Astrophysics Data System (ADS)

    Acharya, U. Rajendra; Tan, Jen Hong; Vidya, S.; Yeo, Sharon; Too, Cheah Loon; Lim, Wei Jie Eugene; Chua, Kuang Chua; Tong, Louis

    2014-11-01

    The dry eye treatment outcome depends on the assessment of clinical relevance of the treatment effect. The potential approach to assess the clinical relevance of the treatment is to identify the symptoms responders and non-responders to the given treatments using the responder analysis. In our work, we have performed the responder analysis to assess the clinical relevance effect of the dry eye treatments namely, hot towel, EyeGiene®, and Blephasteam® twice daily and 12 min session of Lipiflow®. Thermography is performed at week 0 (baseline), at weeks 4 and 12 after treatment. The clinical parameters such as, change in the clinical irritations scores, tear break up time (TBUT), corneal staining and Schirmer's symptoms tests values are used to obtain the responders and non-responders groups. We have obtained the infrared thermography images of dry eye symptoms responders and non-responders to the three types of warming treatments. The energy, kurtosis, skewness, mean, standard deviation, and various entropies namely Shannon, Renyi and Kapoor are extracted from responders and non-responders thermograms. The extracted features are ranked based on t-values. These ranked features are fed to the various classifiers to get the highest performance using minimum features. We have used decision tree (DT), K nearest neighbour (KNN), Naves Bayesian (NB) and support vector machine (SVM) to classify the features into responder and non-responder classes. We have obtained an average accuracy of 99.88%, sensitivity of 99.7% and specificity of 100% using KNN classifier using ten-fold cross validation.

  3. Validation of quantitative IR thermography for estimating the U-value by a hot box apparatus

    NASA Astrophysics Data System (ADS)

    Nardi, I.; Paoletti, D.; Ambrosini, D.; de Rubeis, T.; Sfarra, S.

    2015-11-01

    Energy saving plays a key role in the reduction of energy consumption and carbon emission, and therefore it is essential for reaching the goal of the 20-20-2020 policy. In particular, buildings are responsible of about 30% of the total amount of Europe energy consumption; the increase of their energy efficiency with the reduction of the thermal transmittance of the envelope is a point of strength with the actions and strategies of the policy makers. Currently, the study of energy performance of buildings is based on international standards, in particular the Italian one allows to calculate the U-value according the ISO 6946 or by in-situ measurements, using a heat flow meter (HFM), following recommendations provided in ISO 9869. In the last few years, a new technique, based on Infrared Thermography (IRT) (also referred to as Infrared Thermovision Technique - ITT), has been proposed for in situ determination of the thermal transmittance of opaque building elements. Some case studies have been reported. This method has already been applied on existing buildings, providing reliable results, but also revealing some weaknesses. In order to overcome such weak points and to assess a systematic procedure for the application of IRT, a validation of the method has been performed in a monitored environment. Infrared camera, the heat flow meter sensors and a nearby meteorological station have been used for thermal transmittance measurement. Comparison between the U-values measured in a hot box with IRT as well as values calculated following international standards and HFM results has been effected. Results give a good description of the advantages, as well as of the open problems, of IR Thermography for estimating the U-value. Further studies will help to refine the technique, and to identify the best operative conditions.

  4. Concentration of mycotoxins and chemical composition of corn silage: a farm survey using infrared thermography.

    PubMed

    Schmidt, P; Novinski, C O; Junges, D; Almeida, R; de Souza, C M

    2015-09-01

    This work evaluated the chemical composition and mycotoxin incidence in corn silage from 5 Brazilian dairy-producing regions: Castro, in central-eastern Paraná State (n=32); Toledo, in southwestern Paraná (n=20); southeastern Goiás (n=14); southern Minas Gerais (n=23); and western Santa Catarina (n=20). On each dairy farm, an infrared thermography camera was used to identify 3 sampling sites that exhibited the highest temperature, a moderate temperature, and the lowest temperature on the silo face, and 1 sample was collected from each site. The chemical composition and concentrations of mycotoxins were evaluated, including the levels of aflatoxins B1, B2, G1, and G2; zearalenone; ochratoxin A; deoxynivalenol; and fumonisins B1 and B2. The corn silage showed a highly variable chemical composition, containing, on average, 7.1±1.1%, 52.5±5.4%, and 65.2±3.6% crude protein, neutral detergent fiber, and total digestible nutrients, respectively. Mycotoxins were found in more than 91% of the samples, with zearalenone being the most prevalent (72.8%). All samples from the Castro region contained zearalenone at a high average concentration (334±374µg/kg), even in well-preserved silage. The incidence of aflatoxin B1 was low (0.92%). Silage temperature and the presence of mycotoxins were not correlated; similarly, differences were not observed in the concentration or incidence of mycotoxins across silage locations with different temperatures. Infrared thermography is an accurate tool for identifying heat sites, but temperature cannot be used to predict the chemical composition or the incidence of mycotoxins that have been analyzed, within the silage. The pre-harvest phase of the ensiling process is most likely the main source of mycotoxins in silage.

  5. The uses of infrared thermography to evaluate the effects of climatic variables in bull's reproduction

    NASA Astrophysics Data System (ADS)

    Menegassi, Silvio Renato Oliveira; Pereira, Gabriel Ribas; Dias, Eduardo Antunes; Koetz, Celso; Lopes, Flávio Guiselli; Bremm, Carolina; Pimentel, Concepta; Lopes, Rubia Branco; da Rocha, Marcela Kuczynski; Carvalho, Helena Robattini; Barcellos, Júlio Otavio Jardim

    2016-01-01

    The objective of this study was to evaluate the seasonal effects of the environment on sperm quality in subtropical region determined by temperature and humidity index (THI). We used 20 Brangus bulls (5/8 Angus × 3/8 Nellore) aged approximately 24 months at the beginning of the study. Semen evaluations were performed twice per season during 1 year. Climate THI data were collected from an automatic weather station from the National Institute of Meteorology. Infrared thermography images were used to determine the temperature of the proximal and distal poles of the testis to assess the testicular temperature gradient (TG). The seasonal effects on seminal and climatic variables were analyzed with ANOVA using MIXED procedure of SAS. Sperm motility in spring (60.1 %), summer (57.6 %), and autumn (64.5 %) showed difference compared to winter (73.0 %; P < 0.01). TG was negatively correlated with THI at 18 days (spermiogenesis) (-0.76; P < 0.05) and at 12 days (epididymal transit) (-0.85; P < 0.01). Ocular temperature (OcT) had a positive correlation with THI at 18 days (0.78; P < 0.05) and at 12 days (0.84; P < 0.01). Motility showed a negative correlation with THI only at 18 days (-0.79; P < 0.05). During spermiogenesis, the TG had higher negative correlation compared to OcT (-0.97; P < 0.01) and rectal temperature (-0.72; P < 0.05). Spermatozoa with distal midpiece reflex were correlated with THI during transit epididymis (0.72; P < 0.05). Seminal parameters are not affected when THI reaches 93.0 (spermiogenesis) and 88.0 (epididymal transit). We concluded that infrared thermography can be adopted as an indirect method in order to assess the effect of environmental changes in TG and OcT of Brangus bulls.

  6. The use of infrared thermography in the evaluation of oral lesions.

    PubMed

    White, B A; Lockhart, P B; Connolly, S F; Sonis, S T

    1987-01-01

    We have attempted to quantify the degree of inflammation associated with oral lesions through the use of infrared thermography, since the increased vascularity associated with inflamed tissue might result in measurable increases in surface temperature. This would provide a better measure of the relief of pain and inflammation associated with cancer chemotherapy mucositis by an antiinflammatory drug such as benzydamine hydrochloride than the subjective pain scales now employed. One subject with normal oral mucosa and three subjects with oral lesions of varying aetiology were studied with a Hughes Series 4000 PROBEYE thermal video system utilizing an infrared imager and microprocessor. A 35-mm camera was used to obtain a colour photograph of each subject. Multiple thermograms were made in a temperature range of 30.0 degrees C to 34.2 degrees C at a sensitivity of 0.2 degrees C. Photographs were taken on different occasions to determine whether the temperature readings could be duplicated and to test the accuracy of each reading. The normal surface temperature of the control subject's mucosa was found to be significantly cooler than clinical areas of inflammation in patients with lesions induced by chemotherapy. The temperature of the areas of stomatitis was remarkably consistent (Subject C means 33.7 degrees C; Subject D means 33.9 degrees C). Interestingly, the necrotic center of a traumatic ulcer inhibited measurement of an underlying inflamed base and was thus equivalent in temperature to the normal control (Normal means 31.9 degrees C; Subject B necrotic lesion means 31.7 degrees C). These results suggest that infrared thermography may represent a means to assess quantitatively the degree of mucosal inflammation. Additional studies are in progress. PMID:3610508

  7. Using infrared thermography to evaluate the injuries of cold-stored guava.

    PubMed

    Gonçalves, Bárbara Jordana; Giarola, Tales Márcio de Oliveira; Pereira, Daniele Fernanda; Vilas Boas, Eduardo Valério de Barros; de Resende, Jaime Vilela

    2016-02-01

    This study aimed to identify using the infrared (IR) thermography data the injuries of guavas during cooling and storage at different temperatures. Three experiments were performed at three different temperatures with one storage time. The first experiment was done with static air in a refrigerator at 5 °C, the second experiment was conducted in a tunnel with forced air at 10 °C, and the third experiment was conducted in an air conditioned environment at 20 °C. Mechanical injuries caused by the impact of a pendulum were induced on guava surfaces. The surface temperatures were obtained for bruised and sound tissues during cooling and storage using an Infrared (IR) camera. With thermography, it was possible to distinguish the injured tissues of the fruits that were unaffected at temperatures of 5, 10 and 20 °C in first hours of cooling. The results suggest that the storage of guava fruits at 5 °C in static air resulted in cold-induced injury, while storage at 20 °C resulted in an altered activity pattern. The stored guava fruits were analyzed for mass loss, firmness, color, total sugars, total pectin and solubility. The parameters values were lower during the forced-air cooling and storage at 5 and 10 °C. When stored at 20 °C, there was fruit maturation that caused tissue softening, which makes the fruits more susceptible to deterioration and thermographic readings showed opposite trends. PMID:27162386

  8. Examining gender specificity of sexual response with concurrent thermography and plethysmography.

    PubMed

    Huberman, Jackie S; Chivers, Meredith L

    2015-10-01

    Men's genital responses are significantly greater to sexual stimuli of their preferred gender compared to their nonpreferred gender (gender-specific), whereas androphilic (i.e., sexually attracted to men) women's genital responses are similar to sexual stimuli depicting either women or men (gender-nonspecific). This gendered pattern of genital response has only been demonstrated using vaginal photoplethysmography (VPP) in women and primarily penile plethysmography (PPG) in men. These measures assess different aspects of genital vasocongestion, thereby limiting comparisons between genders. Thermography is a newer sexual psychophysiology methodology that measures genital vasocongestion via temperature change and is better suited to assess sexual response between genders because the dependent measure, change in genital temperature, is similar for women and men. Further, previous studies have assessed gender specificity of sexual response across relatively short sexual stimuli, allowing only the examination of initial phases of sexual response. We examined gender specificity of sexual arousal by measuring women's and men's genital responses to lengthier stimuli with concurrent thermography and VPP/PPG. Gynephilic men (i.e., sexually attracted to women; n = 27) and androphilic women (n = 28) viewed 10-min films depicting men masturbating, women masturbating, and a nonsexual film, and reported feelings of sexual arousal while genital responses were assessed. Across measures, men's sexual responses were gender-specific and women's responses were gender-nonspecific, indicating that the gender difference in gender specificity of arousal is robust to methodology and stimulus duration. These findings replicate previous research, extend knowledge of gendered sexual response, and highlight the utility of multimethod approaches in sexual psychophysiology.

  9. Modeling static and dynamic thermography of the human breast under elastic deformation.

    PubMed

    Jiang, Li; Zhan, Wang; Loew, Murray H

    2011-01-01

    An abnormal thermogram has been shown to be a reliable indicator of increased risk of breast cancer. Numerical modeling techniques for thermography are proposed to quantify the complex relationships between the breast thermal behaviors and the underlying physiological/pathological conditions. Previous thermal modeling techniques did not account for gravity-induced elastic deformation arising from various body postures, nor did they suggest that a dynamic thermal procedure may be used to enhance clinical diagnosis. In this paper, 3D finite element method (FEM)-based thermal and elastic modeling techniques are developed to characterize comprehensively both the thermal and elastic properties of normal and tumorous breast tissues during static and dynamic thermography. In the steady state, gravity-induced breast deformation is found to cause an upper-lower asymmetric surface temperature contrast for sitting/standing up body posture, even though all the thermal and elastic properties are assumed uniform. Additionally, the tumor-induced surface temperature alterations are found to be caused primarily by shallow tumors and to be less sensitive to tumor size than to tumor depth. In the dynamic state, the breast exhibits distinctive temporal patterns that are associated with distinct thermal events: cold stress and thermal recovery induced by changes in the ambient temperature. Specifically, the tumor-induced thermal contrast shows an opposite initial change and delayed peak as compared with the deformation-induced thermal contrast. These findings are expected to provide a stronger foundation for, and greater specificity and precision in, thermographic diagnosis, and treatment of breast cancer.

  10. [Objective assessment of facial paralysis using infrared thermography and formal concept analysis].

    PubMed

    Liu, Xu-Long; Hong, Wen-Xue; Liu, Jie-Min

    2014-04-01

    This paper presented a novel approach to objective assessment of facial nerve paralysis based on infrared thermography and formal concept analysis. Sixty five patients with facial nerve paralysis on one side were included in the study. The facial temperature distribution images of these 65 patients were captured by infrared thermography every five days during one-month period. First, the facial thermal images were pre-processed to identify six potential regions of bilateral symmetry by using image segmentation techniques. Then, the temperature differences on the left and right sides of the facial regions were extracted and analyzed. Finally, the authors explored the relationships between the statistical averages of those temperature differences and the House-Brackmann score for objective assessment degree of nerve damage in a facial nerve paralysis by using formal concept analysis. The results showed that the facial temperature distribution of patients with facial nerve paralysis exhibited a contralateral asymmetry, and the bilateral temperature differences of the facial regions were greater than 0.2 degrees C, whereas in normal healthy individuals these temperature differences were less than 0.2 degrees C. Spearman correlation coefficient between the bilateral temperature differences of the facial regions and the degree of facial nerve damage was an average of 0.508, which was statistically significant (p < 0.05). Furthermore, if one of the temperature differences of bilateral symmetry on facial regions was greater than 0.2 degrees C, and all were less than 0.5 degrees C, facial nerve paralysis could be determined as for the mild to moderate; if one of the temperature differences of bilateral symmetry was greater than 0.5 degrees C, facial nerve paralysis could be determined as for serious. In conclusion, this paper presents an automated technique for the computerized analysis of thermal images to objectively assess facial nerve related thermal dysfunction by

  11. Neonatal non-contact respiratory monitoring based on real-time infrared thermography

    PubMed Central

    2011-01-01

    Background Monitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration rate of the neonate. It will be shown that the respiration rate of neonates can be monitored based on analysis of the anterior naris (nostrils) temperature profile associated with the inspiration and expiration phases successively. Objective The aim of this study is to develop and investigate a new non-contact respiration monitoring modality for neonatal intensive care unit (NICU) using infrared thermography imaging. This development includes subsequent image processing (region of interest (ROI) detection) and optimization. Moreover, it includes further optimization of this non-contact respiration monitoring to be considered as physiological measurement inside NICU wards. Results Continuous wavelet transformation based on Debauches wavelet function was applied to detect the breathing signal within an image stream. Respiration was successfully monitored based on a 0.3°C to 0.5°C temperature difference between the inspiration and expiration phases. Conclusions Although this method has been applied to adults before, this is the first time it was used in a newborn infant population inside the neonatal intensive care unit (NICU). The promising results suggest to include this technology into advanced NICU monitors. PMID:22243660

  12. [Diagnosing Low Health and Wood Borer Attacked Trees of Chinese Arborvitae by Using Thermography].

    PubMed

    Wang, Fei; Wu, De-jun; Zhai, Guo-feng; Zang, Li-peng

    2015-12-01

    Water and energy metabolism of plants is very important actions in their lives. Although the studies about these actions by using thermography were often reported, seldom were found in detecting the health status of forest trees. In this study, we increase the measurement accuracy and comparability of thermo-images by creating the difference indices. Based on it, we exam the water and energy status in stem of Chinese arborvitae (Platycladus orientalis (L.) Franco) by detecting the variance of far infrared spectrum between sap-wood and heart-wood of the cross-section of felling trees and the cores from an increment borer using thermography. The results indicate that the sap rate between sapwood and heartwood is different as the variance of the vigor of forest trees. Meanwhile, the image temperature of scale leaves from Chinese arborvitae trees with different vigor is also dissimilar. The far infrared spectrum more responds the sap status not the wood percentage in comparing to the area rate between sapwood and heartwood. The image temperature rate can be used in early determining the health status of Chinese arborvitae trees. The wood borers such as Phloeosinus aubei Perris and Semanotus bifasciatus Motschulsky are the pests which usually attack the low health trees, dying trees, wilted trees, felled trees and new cultivated trees. This measuring technique may be an important index to diagnose the health and vigor status after a large number of measurements for Chinese arborvitae trees. Therefore, there is potential to be an important index to check the tree vigor and pest damage status by using this technique. It will be a key in the tending and management of ecological and public Chinese arborvitae forest.

  13. Infrared contrast data analysis method for quantitative measurement and monitoring in flash infrared thermography

    NASA Astrophysics Data System (ADS)

    Koshti, Ajay M.

    2015-04-01

    The paper provides information on a new infrared (IR) image contrast data post-processing method that involves converting raw data to normalized contrast versus time evolutions from the flash infrared thermography inspection video data. Thermal measurement features such as peak contrast, peak contrast time, persistence time, and persistence energy are calculated from the contrast evolutions. In addition, simulation of the contrast evolution is achieved through calibration on measured contrast evolutions from many flat bottom holes in a test plate of the subject material. The measurement features are used to monitor growth of anomalies and to characterize the void-like anomalies. The method was developed to monitor and analyze void-like anomalies in reinforced carbon-carbon (RCC) materials used on the wing leading edge of the NASA Space Shuttle Orbiters, but the method is equally applicable to other materials. The thermal measurement features relate to the anomaly characteristics such as depth and size. Calibration of the contrast is used to provide an assessment of the anomaly depth and width which correspond to the depth and diameter of the equivalent flat bottom hole (EFBH) from the calibration data. An edge detection technique called the half-max is used to measure width and length of the anomaly. Results of the half-max width and the EFBH diameter are compared with actual widths to evaluate utility of IR Contrast method. Some thermal measurements relate to gap thickness of the delaminations. Results of IR Contrast method on RCC hardware are provided. Keywords: normalized contrast, flash infrared thermography.

  14. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

    This invention is comprised of a compact acoustic refrigeration system that actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment.

  15. Acoustics lecturing in Mexico

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio

    2002-11-01

    Some thirty years ago acoustics lecturing started in Mexico at the National Polytechnic Institute in Mexico City, as part of the Bachelor of Science degree in Communications and Electronics Engineering curricula, including the widest program on this field in the whole country. This program has been producing acoustics specialists ever since. Nowadays many universities and superior education institutions around the country are teaching students at the B.Sc. level and postgraduate level many topics related to acoustics, such as Architectural Acoustics, Seismology, Mechanical Vibrations, Noise Control, Audio, Audiology, Music, etc. Also many institutions have started research programs in related fields, with participation of medical doctors, psychologists, musicians, engineers, etc. Details will be given on particular topics and development.

  16. Compact acoustic refrigerator

    DOEpatents

    Bennett, G.A.

    1992-11-24

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

  17. Acoustic imaging system

    DOEpatents

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  18. Acoustic Neuroma Association

    MedlinePlus

    ... Platinum Sponsors More from this sponsor... Platinum Sponsor Gold Sponsor University of Colorado Acoustic Neuroma Program Rocky Mountain Gamma Knife Center Gold Sponsor NYU Langone Medical Center Departments of Neurosurgery ...

  19. Acoustic-Levitation Chamber

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Granett, D.; Lee, M. C.

    1984-01-01

    Uncontaminated environments for highly-pure material processing provided within completely sealed levitation chamber that suspends particles by acoustic excitation. Technique ideally suited for material processing in low gravity environment of space.

  20. Multimode Acoustic Research

    NASA Technical Reports Server (NTRS)

    Barmatz, M.

    1985-01-01

    There is a need for high temperature containerless processing facilities that can efficiently position and manipulate molten samples in the reduced gravity environment of space. The goal of the research is to develop sophisticated high temperature manipulation capabilities such as selection of arbitrary axes rotation and rapid sample cooling. This program will investigate new classes of acoustic levitation in rectangular, cylindrical and spherical geometries. The program tasks include calculating theoretical expressions of the acoustic forces in these geometries for the excitation of up to three acoustic modes (multimodes). These calculations are used to: (1) determine those acoustic modes that produce stable levitation, (2) isolate the levitation and rotation capabilities to produce more than one axis of rotation, and (3) develop methods to translate samples down long tube cylindrical chambers. Experimental levitators will then be constructed to verify the stable levitation and rotation predictions of the models.

  1. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A.

    1992-01-01

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

  2. Numerical Techniques in Acoustics

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J. (Compiler)

    1985-01-01

    This is the compilation of abstracts of the Numerical Techniques in Acoustics Forum held at the ASME's Winter Annual Meeting. This forum was for informal presentation and information exchange of ongoing acoustic work in finite elements, finite difference, boundary elements and other numerical approaches. As part of this forum, it was intended to allow the participants time to raise questions on unresolved problems and to generate discussions on possible approaches and methods of solution.

  3. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface

    NASA Astrophysics Data System (ADS)

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-11-01

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell’s law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications.

  4. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface.

    PubMed

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A

    2014-11-24

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications.

  5. Acoustic detection of pneumothorax

    NASA Astrophysics Data System (ADS)

    Mansy, Hansen A.; Royston, Thomas J.; Balk, Robert A.; Sandler, Richard H.

    2003-04-01

    This study aims at investigating the feasibility of using low-frequency (<2000 Hz) acoustic methods for medical diagnosis. Several candidate methods of pneumothorax detection were tested in dogs. In the first approach, broadband acoustic signals were introduced into the trachea during end-expiration and transmitted waves were measured at the chest surface. Pneumothorax was found to consistently decrease pulmonary acoustic transmission in the 200-1200-Hz frequency band, while less change was observed at lower frequencies (p<0.0001). The ratio of acoustic energy between low (<220 Hz) and mid (550-770 Hz) frequency bands was significantly different in the control (healthy) and pneumothorax states (p<0.0001). The second approach measured breath sounds in the absence of an external acoustic input. Pneumothorax was found to be associated with a preferential reduction of sound amplitude in the 200- to 700-Hz range, and a decrease of sound amplitude variation (in the 300 to 600-Hz band) during the respiration cycle (p<0.01 for each). Finally, chest percussion was implemented. Pneumothorax changed the frequency and decay rate of percussive sounds. These results imply that certain medical conditions may be reliably detected using appropriate acoustic measurements and analysis. [Work supported by NIH/NHLBI #R44HL61108.

  6. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography. PMID:26723303

  7. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography.

  8. A compact acoustic recorder

    NASA Astrophysics Data System (ADS)

    Stein, Ronald

    1989-09-01

    The design and operation of a portable compact acoustic recorder is discussed. Designed to be used in arctic conditions for applications that require portable equipment, the device is configured to fit into a lightweight briefcase. It will operate for eight hours at -40 F with heat provided by a hot water bottle. It has proven to be an effective scientific tool in the measurement of underwater acoustic signals in arctic experiments. It has also been used successfully in warmer climates, e.g., in recording acoustic signals from small boats with no ac power. The acoustic recorder's cost is moderate since it is based on a Sony Walkman Professional (WM-D6C) tape recorder playback unit. A speaker and battery assembly and a hydrophone interface electronic assembly complete the system electronics. The interface assembly supplies a number of functions, including a calibration tone generator, an audio amplifier, and a hydrophone interface. Calibrated acoustic recordings can be made by comparing the calibration tone amplitude with the acoustic signal amplitude. The distortion of the recording is minimized by using a high quality, consumer tape recorder.

  9. Acoustic communication by ants

    NASA Astrophysics Data System (ADS)

    Hickling, Robert

    2002-05-01

    Many ant species communicate acoustically by stridulating, i.e., running a scraper over a washboard-like set of ridges. Ants appear to be insensitive to airborne sound. Consequently, myrmecologists have concluded that the stridulatory signals are transmitted through the substrate. This has tended to diminish the importance of acoustic communication, and it is currently believed that ant communication is based almost exclusively on pheromones, with acoustic communication assigned an almost nonexistent role. However, it can be shown that acoustic communication between ants is effective only if the medium is air and not the substrate. How, then, is it possible for ants to appear deaf to airborne sound and yet communicate through the air? An explanation is provided in a paper [R. Hickling and R. L. Brown, ``Analysis of acoustic communication by ants,'' J. Acoust. Soc. Am. 108, 1920-1929 (2000)]. Ants are small relative to the wavelengths they generate. Hence, they create a near field, which is characterized by a major increase in sound velocity (particle velocity of sound) in the vicinity of the source. Hair sensilla on the ants' antennae respond to sound velocity. Thus, ants are able to detect near-field sound from other ants and to exclude extraneous airborne sound.

  10. A comparative study of principal component analysis and independent component analysis in eddy current pulsed thermography data processing.

    PubMed

    Bai, Libing; Gao, Bin; Tian, Shulin; Cheng, Yuhua; Chen, Yifan; Tian, Gui Yun; Woo, W L

    2013-10-01

    Eddy Current Pulsed Thermography (ECPT), an emerging Non-Destructive Testing and Evaluation technique, has been applied for a wide range of materials. The lateral heat diffusion leads to decreasing of temperature contrast between defect and defect-free area. To enhance the flaw contrast, different statistical methods, such as Principal Component Analysis and Independent Component Analysis, have been proposed for thermography image sequences processing in recent years. However, there is lack of direct and detailed independent comparisons in both algorithm implementations. The aim of this article is to compare the two methods and to determine the optimized technique for flaw contrast enhancement in ECPT data. Verification experiments are conducted on artificial and thermal fatigue nature crack detection.

  11. Investigation of defect characteristics and heat transfer in step heating thermography of metal plates repaired with composite patches

    NASA Astrophysics Data System (ADS)

    Daryabor, P.; Safizadeh, M. S.

    2016-05-01

    Nowadays, composite patches are widely used in different industries to repair damaged metal structures. Inspection of such repaired structures is always considered as a challenging task. Different thermography methods such as step heating are commonly used to inspect repaired structures. Some parameters such as defect features or heating procedure play major roles in defect detection. In this work, in order to investigate such effects, step heating thermography of an aluminum plate repaired with a composite patch is modeled and tested. The main goal of this study is to evaluate the effects of defect type (delamination and disbond), size and depth on the detection ability of the test. Moreover, regarding the heat transfer process obtained from the simulation, the appropriate heating procedure for inspecting the repaired metal structures is determined. To validate the simulation outputs, experimental results corresponding to the temperature variations are compared with those predicted from the simulation.

  12. A comparative study of principal component analysis and independent component analysis in eddy current pulsed thermography data processing

    NASA Astrophysics Data System (ADS)

    Bai, Libing; Gao, Bin; Tian, Shulin; Cheng, Yuhua; Chen, Yifan; Tian, Gui Yun; Woo, W. L.

    2013-10-01

    Eddy Current Pulsed Thermography (ECPT), an emerging Non-Destructive Testing and Evaluation technique, has been applied for a wide range of materials. The lateral heat diffusion leads to decreasing of temperature contrast between defect and defect-free area. To enhance the flaw contrast, different statistical methods, such as Principal Component Analysis and Independent Component Analysis, have been proposed for thermography image sequences processing in recent years. However, there is lack of direct and detailed independent comparisons in both algorithm implementations. The aim of this article is to compare the two methods and to determine the optimized technique for flaw contrast enhancement in ECPT data. Verification experiments are conducted on artificial and thermal fatigue nature crack detection.

  13. High-frequency heterodyne lock-in thermography (HeLIT): A highly sensitive method to detect early caries

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Liu, Jun-yan; Yang, Jun-han; Oliullah, Md.; Wang, Xiao-chun; Wang, Yang

    2016-10-01

    In this letter, a nonlinear photothermal characteristic of dental tissues has been verified by photothermal radiometry at a given frequency with changing of the laser intensity. Subsequently, the high-frequency heterodyne lock-in thermography (HeLIT) scheme has been introduced to overcome shortages of the low infrared camera frame rate and the poor signal-noise ratio. The smooth surface tooth was artificially demineralized at a different time, and then it was detected by HeLIT, Results illustrated that the phase delay increases with the extension of the demineralized treatment time. The comparison experiments between HeLIT and the homodyne lock-in thermography for detecting artificial caries were carried out. Experimental results illustrated that the HeLIT has the merits of high sensitivity and specificity in detecting early caries.

  14. Measurement of Three-Dimensional Anisotropic Thermal Diffusivities for Carbon Fiber-Reinforced Plastics Using Lock-In Thermography

    NASA Astrophysics Data System (ADS)

    Ishizaki, Takuya; Nagano, Hosei

    2015-11-01

    A new measurement technique to measure the in-plane thermal diffusivity, the distribution of in-plane anisotropy, and the out-of-plane thermal diffusivity has been developed to evaluate the thermal conductivity of anisotropic materials such as carbon fiber-reinforced plastics (CFRPs). The measurements were conducted by using a laser-spot-periodic-heating method. The temperature of the sample is detected by using lock-in thermography. Thermography can analyze the phase difference between the periodic heat input and the temperature response of the sample. Two kinds of samples, unidirectional (UD) and cross-ply (CP) pitch-based CFRPs, were fabricated and tested in an atmospheric condition. All carbon fibers of the UD sample run in one direction [90°]. The carbon fibers of the CP sample run in two directions [0°/90°]. It is found that, by using lock-in thermography, it is able to visualize the thermal anisotropy and calculate the angular dependence of the in-plane thermal diffusivity of the CFRPs. The out-of-plane thermal diffusivity of CFRPs was also measured by analyzing the frequency dependence of the phase difference.

  15. Active thermography and post-processing image enhancement for recovering of abraded and paint-covered alphanumeric identification marks

    NASA Astrophysics Data System (ADS)

    Montanini, R.; Quattrocchi, A.; Piccolo, S. A.

    2016-09-01

    Alphanumeric marking is a common technique employed in industrial applications for identification of products. However, the realised mark can undergo deterioration, either by extensive use or voluntary deletion (e.g. removal of identification numbers of weapons or vehicles). For recovery of the lost data many destructive or non-destructive techniques have been endeavoured so far, which however present several restrictions. In this paper, active infrared thermography has been exploited for the first time in order to assess its effectiveness in restoring paint covered and abraded labels made by means of different manufacturing processes (laser, dot peen, impact, cold press and scribe). Optical excitation of the target surface has been achieved using pulse (PT), lock-in (LT) and step heating (SHT) thermography. Raw infrared images were analysed with a dedicated image processing software originally developed in Matlab™, exploiting several methods, which include thermographic signal reconstruction (TSR), guided filtering (GF), block guided filtering (BGF) and logarithmic transformation (LN). Proper image processing of the raw infrared images resulted in superior contrast and enhanced readability. In particular, for deeply abraded marks, good outcomes have been obtained by application of logarithmic transformation to raw PT images and block guided filtering to raw phase LT images. With PT and LT it was relatively easy to recover labels covered by paint, with the latter one providing better thermal contrast for all the examined targets. Step heating thermography never led to adequate label identification instead.

  16. Study of a brittle and precious medieval rose-window by means of the integration of GPR, stress wave tests and infrared thermography

    NASA Astrophysics Data System (ADS)

    Nuzzo, L.; Masini, N.; Rizzo, E.

    2009-04-01

    The correct management and restoration of architectural monuments of high cultural interest requires a comprehensive understanding of their status of preservation, the detection of the building features, the localization of damages and possibly the identification of their causes, nature and extent. To this aim, in recent times there is a growing interest on non-destructive and non-invasive geophysical methods as an invaluable tool for correlating spatially the information gained through destructive tests, which are restricted to a few locations of the investigated structure, and to optimize the choice of their position in order to minimize their impact on the monument structural stability. Moreover, the integration of the classical geophysical techniques with emerging surface and subsurface sensing techniques (acoustics, thermography) provides a suitable methodology for a multi-scale assessment of the monument state of preservation and its material and building components, which is vital for addressing maintenance and restoration issues. The present case study focuses on the application of Ground Penetrating Radar (GPR), infrared thermography (IRT), sonic and ultrasonic tests to analyze a 13th century precious rose window in Southern Italy, affected by widespread decay and instability problems. The Cathedral of Troia (Apulia, Italy) is the masterpiece of the Apulian Romanesque architecture. Its façade is adorned with an astonishing 6 m diameter rose window consisting of 11 twin columns, in various stone and reused marbles, connected to a central oculus and to a ring of trapezoidal elements decorated with arched ribworks. Between the twin columns there are 11 triangular carved panels with different and strongly symbolic geometrical patterns. According to visual inspection, mineralogical and petrographic studies, different materials have been used for the different architectural elements: fine grained limestone for the central oculus, medium-fine grained calcarenite

  17. Measuring acoustic habitats

    PubMed Central

    Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E

    2015-01-01

    1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies. PMID:25954500

  18. Acoustic Imaging in Helioseismology

    NASA Astrophysics Data System (ADS)

    Chou, Dean-Yi; Chang, Hsiang-Kuang; Sun, Ming-Tsung; LaBonte, Barry; Chen, Huei-Ru; Yeh, Sheng-Jen; Team, The TON

    1999-04-01

    The time-variant acoustic signal at a point in the solar interior can be constructed from observations at the surface, based on the knowledge of how acoustic waves travel in the Sun: the time-distance relation of the p-modes. The basic principle and properties of this imaging technique are discussed in detail. The helioseismic data used in this study were taken with the Taiwan Oscillation Network (TON). The time series of observed acoustic signals on the solar surface is treated as a phased array. The time-distance relation provides the phase information among the phased array elements. The signal at any location at any time can be reconstructed by summing the observed signal at array elements in phase and with a proper normalization. The time series of the constructed acoustic signal contains information on frequency, phase, and intensity. We use the constructed intensity to obtain three-dimensional acoustic absorption images. The features in the absorption images correlate with the magnetic field in the active region. The vertical extension of absorption features in the active region is smaller in images constructed with shorter wavelengths. This indicates that the vertical resolution of the three-dimensional images depends on the range of modes used in constructing the signal. The actual depths of the absorption features in the active region may be smaller than those shown in the three-dimensional images.

  19. [Acoustic characteristics of classrooms].

    PubMed

    Koszarny, Zbigniew; Chyla, Andrzej

    2003-01-01

    Quality and usefulness of school rooms for transmission of verbal information depends on the two basic parameters: form and quantity of the reverberation time, and profitable line measurements of school rooms from the acoustic point of view. An analysis of the above-mentioned parameters in 48 class rooms and two gymnasiums in schools, which were built in different periods, shows that the most important problem is connected with too long reverberation time and inappropriate acoustic proportions. In schools built in the 1970s, the length of reverberation time is mostly within a low frequency band, while in schools built contemporarily, the maximum length of disappearance time takes place in a quite wide band of 250-2000 Hz. This exceeds optimal values for that kind of rooms at least twice, and five times in the newly built school. A long reverberation time is connected with a low acoustic absorption of school rooms. Moreover, school rooms are characterised by inappropriate acoustic proportions. The classrooms, in their relation to the height, are too long and too wide. It is connected with deterioration of the transmission of verbal information. The data show that this transmission is unequal. Automatically, it leads to a speech disturbance and difficulties with understanding. There is the need for adaptation of school rooms through increase of an acoustic absorption.

  20. Acoustic emission monitoring system

    DOEpatents

    Romrell, Delwin M.

    1977-07-05

    Methods and apparatus for identifying the source location of acoustic emissions generated within an acoustically conductive medium. A plurality of acoustic receivers are communicably coupled to the surface of the medium at a corresponding number of spaced locations. The differences in the reception time of the respective sensors in response to a given acoustic event are measured among various sensor combinations prescribed by the monitoring mode employed. Acoustic reception response encountered subsequent to the reception by a predetermined number of the prescribed sensor combinations are inhibited from being communicated to the processing circuitry, while the time measurements obtained from the prescribed sensor combinations are translated into a position measurement representative of the location on the surface most proximate the source of the emission. The apparatus is programmable to function in six separate and five distinct operating modes employing either two, three or four sensory locations. In its preferred arrangement the apparatus of this invention will re-initiate a monitoring interval if the predetermined number of sensors do not respond to a particular emission within a given time period.

  1. ACOUSTICS IN ARCHITECTURAL DESIGN, AN ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS.

    ERIC Educational Resources Information Center

    DOELLE, LESLIE L.

    THE PURPOSE OF THIS ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS WAS--(1) TO COMPILE A CLASSIFIED BIBLIOGRAPHY, INCLUDING MOST OF THOSE PUBLICATIONS ON ARCHITECTURAL ACOUSTICS, PUBLISHED IN ENGLISH, FRENCH, AND GERMAN WHICH CAN SUPPLY A USEFUL AND UP-TO-DATE SOURCE OF INFORMATION FOR THOSE ENCOUNTERING ANY ARCHITECTURAL-ACOUSTIC DESIGN…

  2. The uses of infrared thermography to evaluate the effects of climatic variables in bull's reproduction.

    PubMed

    Menegassi, Silvio Renato Oliveira; Pereira, Gabriel Ribas; Dias, Eduardo Antunes; Koetz, Celso; Lopes, Flávio Guiselli; Bremm, Carolina; Pimentel, Concepta; Lopes, Rubia Branco; da Rocha, Marcela Kuczynski; Carvalho, Helena Robattini; Barcellos, Júlio Otavio Jardim

    2016-01-01

    The objective of this study was to evaluate the seasonal effects of the environment on sperm quality in subtropical region determined by temperature and humidity index (THI). We used 20 Brangus bulls (5/8 Angus × 3/8 Nellore) aged approximately 24 months at the beginning of the study. Semen evaluations were performed twice per season during 1 year. Climate THI data were collected from an automatic weather station from the National Institute of Meteorology. Infrared thermography images were used to determine the temperature of the proximal and distal poles of the testis to assess the testicular temperature gradient (TG). The seasonal effects on seminal and climatic variables were analyzed with ANOVA using MIXED procedure of SAS. Sperm motility in spring (60.1%), summer (57.6%), and autumn (64.5%) showed difference compared to winter (73.0%; P < 0.01). TG was negatively correlated with THI at 18 days (spermiogenesis) (-0.76; P < 0.05) and at 12 days (epididymal transit) (-0.85; P < 0.01). Ocular temperature (OcT) had a positive correlation with THI at 18 days (0.78; P < 0.05) and at 12 days (0.84; P < 0.01). Motility showed a negative correlation with THI only at 18 days (-0.79; P < 0.05). During spermiogenesis, the TG had higher negative correlation compared to OcT (-0.97; P < 0.01) and rectal temperature (-0.72; P < 0.05). Spermatozoa with distal midpiece reflex were correlated with THI during transit epididymis (0.72; P < 0.05). Seminal parameters are not affected when THI reaches 93.0 (spermiogenesis) and 88.0 (epididymal transit). We concluded that infrared thermography can be adopted as an indirect method in order to assess the effect of environmental changes in TG and OcT of Brangus bulls. PMID:26049285

  3. The uses of infrared thermography to evaluate the effects of climatic variables in bull's reproduction.

    PubMed

    Menegassi, Silvio Renato Oliveira; Pereira, Gabriel Ribas; Dias, Eduardo Antunes; Koetz, Celso; Lopes, Flávio Guiselli; Bremm, Carolina; Pimentel, Concepta; Lopes, Rubia Branco; da Rocha, Marcela Kuczynski; Carvalho, Helena Robattini; Barcellos, Júlio Otavio Jardim

    2016-01-01

    The objective of this study was to evaluate the seasonal effects of the environment on sperm quality in subtropical region determined by temperature and humidity index (THI). We used 20 Brangus bulls (5/8 Angus × 3/8 Nellore) aged approximately 24 months at the beginning of the study. Semen evaluations were performed twice per season during 1 year. Climate THI data were collected from an automatic weather station from the National Institute of Meteorology. Infrared thermography images were used to determine the temperature of the proximal and distal poles of the testis to assess the testicular temperature gradient (TG). The seasonal effects on seminal and climatic variables were analyzed with ANOVA using MIXED procedure of SAS. Sperm motility in spring (60.1%), summer (57.6%), and autumn (64.5%) showed difference compared to winter (73.0%; P < 0.01). TG was negatively correlated with THI at 18 days (spermiogenesis) (-0.76; P < 0.05) and at 12 days (epididymal transit) (-0.85; P < 0.01). Ocular temperature (OcT) had a positive correlation with THI at 18 days (0.78; P < 0.05) and at 12 days (0.84; P < 0.01). Motility showed a negative correlation with THI only at 18 days (-0.79; P < 0.05). During spermiogenesis, the TG had higher negative correlation compared to OcT (-0.97; P < 0.01) and rectal temperature (-0.72; P < 0.05). Spermatozoa with distal midpiece reflex were correlated with THI during transit epididymis (0.72; P < 0.05). Seminal parameters are not affected when THI reaches 93.0 (spermiogenesis) and 88.0 (epididymal transit). We concluded that infrared thermography can be adopted as an indirect method in order to assess the effect of environmental changes in TG and OcT of Brangus bulls.

  4. Acquisition of the spatial temperature distribution of rock faces by using infrared thermography

    NASA Astrophysics Data System (ADS)

    Beham, Michael; Rode, Matthias; Schnepfleitner, Harald; Sass, Oliver

    2013-04-01

    Rock temperature plays a central role for weathering and therefore influences the risk potential originating from rockfall processes. So far, for the acquisition of temperature mainly point-based measuring methods have been used and accordingly, two-dimensional temperature data is rare. To overcome this limitation, an infrared camera was used to collect and analyse data on the spatial temperature distribution on 10 x 10 m sections of rock faces in the Gesäuse (900m a.s.l.) and in the Dachsteingebirge (2700m a.s.l.) within the framework of the research project ROCKING ALPS (FWF-P24244). The advantage of infrared thermography to capture area-wide temperatures has hardly ever been used in this context. In order to investigate the differences between north-facing and south-facing rock faces at about the same period of time it was necessary to move the camera between the sites. The resulting offset of the time lapse infrared images made it necessary to develop a sophisticated methodology to rectify the captured images in order to create matching datasets for future analysis. With the relatively simple camera used, one of the main challenges was to find a way to convert the colour-scale or grey-scale values of the rectified image back to temperature values after the rectification process. The processing steps were mainly carried out with MATLAB. South-facing rock faces generally experienced higher temperatures and amplitudes compared to the north facing ones. In view of the spatial temperature distribution, the temperatures of shady areas were clearly below those of sunny ones, with the latter also showing the highest amplitudes. Joints and sun-shaded areas were characterised by attenuated diurnal temperature fluctuations closely paralleled to the air temperature. The temperature of protruding rock parts and of loose debris responded very quick to changes in radiation and air temperatures while massive rock reacted more slowly. The potential effects of temperature on

  5. Surface Acoustic Wave Microfluidics

    NASA Astrophysics Data System (ADS)

    Yeo, Leslie Y.; Friend, James R.

    2014-01-01

    Fluid manipulations at the microscale and beyond are powerfully enabled through the use of 10-1,000-MHz acoustic waves. A superior alternative in many cases to other microfluidic actuation techniques, such high-frequency acoustics is almost universally produced by surface acoustic wave devices that employ electromechanical transduction in wafer-scale or thin-film piezoelectric media to generate the kinetic energy needed to transport and manipulate fluids placed in adjacent microfluidic structures. These waves are responsible for a diverse range of complex fluid transport phenomena - from interfacial fluid vibration and drop and confined fluid transport to jetting and atomization - underlying a flourishing research literature spanning fundamental fluid physics to chip-scale engineering applications. We highlight some of this literature to provide the reader with a historical basis, routes for more detailed study, and an impression of the field's future directions.

  6. Acoustic particle separation

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Stoneburner, J. D.; Jacobi, N.; Wang, T. (Inventor)

    1985-01-01

    A method is described which uses acoustic energy to separate particles of different sizes, densities, or the like. The method includes applying acoustic energy resonant to a chamber containing a liquid of gaseous medium to set up a standing wave pattern that includes a force potential well wherein particles within the well are urged towards the center, or position of minimum force potential. A group of particles to be separated is placed in the chamber, while a non-acoustic force such as gravity is applied, so that the particles separate with the larger or denser particles moving away from the center of the well to a position near its edge and progressively smaller lighter particles moving progressively closer to the center of the well. Particles are removed from different positions within the well, so that particles are separated according to the positions they occupy in the well.

  7. Acoustic Levitation Containerless Processing

    NASA Technical Reports Server (NTRS)

    Whymark, R. R.; Rey, C. A.

    1985-01-01

    This research program consists of the development of acoustic containerless processing systems with applications in the areas of research in material sciences, as well as the production of new materials, solid forms with novel and unusual microstructures, fusion target spheres, and improved optical fibers. Efforts have been focused on the containerless processing at high temperatures for producing new kinds of glasses. Also, some development has occurred in the areas of containerlessly supporting liquids at room temperature, with applications in studies of fluid dynamics, potential undercooling of liquids, etc. The high temperature area holds the greatest promise for producing new kinds of glasses and ceramics, new alloys, and possibly unusual structural shapes, such as very uniform hollow glass shells for fusion target applications. High temperature acoustic levitation required for containerless processing has been demonstrated in low-g environments as well as in ground-based experiments. Future activities include continued development of the signals axis acoustic levitator.

  8. Acoustic energy shaping

    NASA Technical Reports Server (NTRS)

    Wang, T. G.; Elleman, D. D. (Inventor)

    1977-01-01

    A suspended mass is shaped by melting all or a selected portion of the mass and applying acoustic energy in varying amounts to different portions of the mass. In one technique for forming an optical waveguide slug, a mass of oval section is suspended and only a portion along the middle of the cross-section is heated to a largely fluid consistency. Acoustic energy is applied to opposite edges of the oval mass to press the unheated opposite edge portions together so as to form bulges at the middle of the mass. In another technique for forming a ribbon of silicon for constructing solar cells, a cylindrical thread of silicon is drawn from a molten mass of silicon, and acoustic energy is applied to opposite sides of the molten thread to flatten it into a ribbon.

  9. Passive broadband acoustic thermometry

    NASA Astrophysics Data System (ADS)

    Anosov, A. A.; Belyaev, R. V.; Klin'shov, V. V.; Mansfel'd, A. D.; Subochev, P. V.

    2016-04-01

    The 1D internal (core) temperature profiles for the model object (plasticine) and the human hand are reconstructed using the passive acoustothermometric broadband probing data. Thermal acoustic radiation is detected by a broadband (0.8-3.5 MHz) acoustic radiometer. The temperature distribution is reconstructed using a priori information corresponding to the experimental conditions. The temperature distribution for the heated model object is assumed to be monotonic. For the hand, we assume that the temperature distribution satisfies the heat-conduction equation taking into account the blood flow. The average error of reconstruction determined for plasticine from the results of independent temperature measurements is 0.6 K for a measuring time of 25 s. The reconstructed value of the core temperature of the hand (36°C) generally corresponds to physiological data. The obtained results make it possible to use passive broadband acoustic probing for measuring the core temperatures in medical procedures associated with heating of human organism tissues.

  10. Latticed pentamode acoustic cloak.

    PubMed

    Chen, Yi; Liu, Xiaoning; Hu, Gengkai

    2015-01-01

    We report in this work a practical design of pentamode acoustic cloak with microstructure. The proposed cloak is assembled by pentamode lattice made of a single-phase solid material. The function of rerouting acoustic wave round an obstacle has been demonstrated numerically. It is also revealed that shear related resonance due to weak shear resistance in practical pentamode lattices punctures broadband feature predicted based on ideal pentamode cloak. As a consequence, the latticed pentamode cloak can only conceal the obstacle in segmented frequency ranges. We have also shown that the shear resonance can be largely reduced by introducing material damping, and an improved broadband performance can be achieved. These works pave the way for experimental demonstration of pentamode acoustic cloak. PMID:26503821

  11. Latticed pentamode acoustic cloak

    PubMed Central

    Chen, Yi; Liu, Xiaoning; Hu, Gengkai

    2015-01-01

    We report in this work a practical design of pentamode acoustic cloak with microstructure. The proposed cloak is assembled by pentamode lattice made of a single-phase solid material. The function of rerouting acoustic wave round an obstacle has been demonstrated numerically. It is also revealed that shear related resonance due to weak shear resistance in practical pentamode lattices punctures broadband feature predicted based on ideal pentamode cloak. As a consequence, the latticed pentamode cloak can only conceal the obstacle in segmented frequency ranges. We have also shown that the shear resonance can be largely reduced by introducing material damping, and an improved broadband performance can be achieved. These works pave the way for experimental demonstration of pentamode acoustic cloak. PMID:26503821

  12. A New Wave of Acoustics.

    ERIC Educational Resources Information Center

    Beyer, Robert

    1981-01-01

    Surveys 50 years of acoustical studies by discussing selected topics including the ear, nonlinear representations, underwater sound, acoustical diagnostics, absorption, electrolytes, phonons, magnetic interaction, and superfluidity and the five sounds. (JN)

  13. Acoustic bubble removal method

    NASA Technical Reports Server (NTRS)

    Trinh, E. H.; Elleman, D. D.; Wang, T. G. (Inventor)

    1983-01-01

    A method is described for removing bubbles from a liquid bath such as a bath of molten glass to be used for optical elements. Larger bubbles are first removed by applying acoustic energy resonant to a bath dimension to drive the larger bubbles toward a pressure well where the bubbles can coalesce and then be more easily removed. Thereafter, submillimeter bubbles are removed by applying acoustic energy of frequencies resonant to the small bubbles to oscillate them and thereby stir liquid immediately about the bubbles to facilitate their breakup and absorption into the liquid.

  14. Acoustic emission intrusion detector

    DOEpatents

    Carver, Donald W.; Whittaker, Jerry W.

    1980-01-01

    An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal.

  15. Electromechanical acoustic liner

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark (Inventor); Cattafesta, III, Louis N. (Inventor); Nishida, Toshikazu (Inventor); Horowitz, Stephen Brian (Inventor)

    2007-01-01

    A multi-resonator-based system responsive to acoustic waves includes at least two resonators, each including a bottom plate, side walls secured to the bottom plate, and a top plate disposed on top of the side walls. The top plate includes an orifice so that a portion of an incident acoustical wave compresses gas in the resonators. The bottom plate or the side walls include at least one compliant portion. A reciprocal electromechanical transducer coupled to the compliant portion of each of the resonators forms a first and second transducer/compliant composite. An electrical network is disposed between the reciprocal electromechanical transducer of the first and second resonator.

  16. Acoustic tooth cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S. (Inventor)

    1982-01-01

    An acoustic oral hygiene unit is described that uses acoustic energy to oscillate mild abrasive particles in a water suspension which is then directed in a low pressure stream onto the teeth. The oscillating abrasives scrub the teeth clean removing food particles, plaque, calculous, and other foreign material from tooth surfaces, interproximal areas, and tooth-gingiva interface more effectively than any previous technique. The relatively low power output and the basic design makes the invention safe and convenient for everyday use in the home without special training. This invention replaces all former means of home dental prophylaxis, and requires no augmentation to fulfill all requirements for daily oral hygienic care.

  17. Densitometry By Acoustic Levitation

    NASA Technical Reports Server (NTRS)

    Trinh, Eugene H.

    1989-01-01

    "Static" and "dynamic" methods developed for measuring mass density of acoustically levitated solid particle or liquid drop. "Static" method, unknown density of sample found by comparison with another sample of known density. "Dynamic" method practiced with or without gravitational field. Advantages over conventional density-measuring techniques: sample does not have to make contact with container or other solid surface, size and shape of samples do not affect measurement significantly, sound field does not have to be know in detail, and sample can be smaller than microliter. Detailed knowledge of acoustic field not necessary.

  18. Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

    2009-01-01

    Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in

  19. Post Treatment of Acoustic Neuroma

    MedlinePlus

    Home What is an AN What is an Acoustic Neuroma? Identifying an AN Symptoms Acoustic Neuroma Keywords Educational Video Pre-Treatment Treatment Options Summary Treatment Options Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions ...

  20. Variable-Position Acoustic Levitation

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Stoneburner, J. D.; Jacobi, N.; Wang, T. G.

    1983-01-01

    Method of acoustic levitation supports objects at positions other than acoustic nodes. Acoustic force is varied so it balances gravitational (or other) force, thereby maintaining object at any position within equilibrium range. Levitation method applicable to containerless processing. Such objects as table-tennis balls, hollow plastic spheres, and balsa-wood spheres levitated in laboratory by new method.

  1. Fundamentals of Acoustics. Psychoacoustics and Hearing. Acoustical Measurements

    NASA Technical Reports Server (NTRS)

    Begault, Durand R.; Ahumada, Al (Technical Monitor)

    1997-01-01

    These are 3 chapters that will appear in a book titled "Building Acoustical Design", edited by Charles Salter. They are designed to introduce the reader to fundamental concepts of acoustics, particularly as they relate to the built environment. "Fundamentals of Acoustics" reviews basic concepts of sound waveform frequency, pressure, and phase. "Psychoacoustics and Hearing" discusses the human interpretation sound pressure as loudness, particularly as a function of frequency. "Acoustic Measurements" gives a simple overview of the time and frequency weightings for sound pressure measurements that are used in acoustical work.

  2. Acoustic subwavelength imaging of subsurface objects with acoustic resonant metalens

    SciTech Connect

    Cheng, Ying; Liu, XiaoJun; Zhou, Chen; Wei, Qi; Wu, DaJian

    2013-11-25

    Early research into acoustic metamaterials has shown the possibility of achieving subwavelength near-field acoustic imaging. However, a major restriction of acoustic metamaterials is that the imaging objects must be placed in close vicinity of the devices. Here, we present an approach for acoustic imaging of subsurface objects far below the diffraction limit. An acoustic metalens made of holey-structured metamaterials is used to magnify evanescent waves, which can rebuild an image at the central plane. Without changing the physical structure of the metalens, our proposed approach can image objects located at certain distances from the input surface, which provides subsurface signatures of the objects with subwavelength spatial resolution.

  3. Reduction of evaporative flux in bean leaves due to chitosan treatment assessed by infrared thermography

    NASA Astrophysics Data System (ADS)

    Ludwig, N.; Cabrini, R.; Faoro, F.; Gargano, M.; Gomarasca, S.; Iriti, M.; Picchi, V.; Soave, C.

    2010-01-01

    Infrared thermography can be used as a tool for evaluating antitranspirant treatment through the measurement of evaporative fluxes. The aim of this work is to compare the leaf surface temperatures of plant treated with chitosan (CHT), a potential stomatal-closing antitranspirant, with temperatures of leaves treated with the commercially available antitranspirant Vapor Gard®, a film-forming polyterpene. The main problem in the correct evaluation of stomatal conductance at leaf level is due to the need of performing a measurement in a completely non-invasive method. The main advantage of thermographic method is the possibility to acquire information about instantaneous conditions of transpiration over a large number of plants, with no need of sampling and avoiding any contact with plants. Tests on bean plants ( Phaseolus vulgaris) showed the applicability of the thermal imaging to discriminate plants with different evaporation rate due to treatment with different antitranspirant compounds. Quantitative evaluation of evaporative flux and stomatal conductance was obtained through reference measurements on standards with calibrated conductance. Non-destructive gravimetric measurements were used in order to get a reliable evaluation of evaporative fluxes. In conclusion, thermographic approach, in climatic chamber, seems to be a valid tool for rapidly screening the performance of different antitranspirant products.

  4. Use of infrared thermography in children with shock: A case series

    PubMed Central

    Ortiz-Dosal, Alejandra; Rivera-Vega, Rosalina; Simón, Jorge; González, Francisco J

    2014-01-01

    Shock is a complex clinical syndrome caused by an acute failure of circulatory function resulting in inadequate tissue and organ perfusion. Digital infrared thermal imaging is a non-invasive technique that can detect changes in blood perfusion by detecting small changes in the temperature of the skin. In this preliminary study, eight pediatric patients (five boys, three girls), ages ranging from 6 to 14 years (average: 9.8 years), were admitted to the Intensive Care Unit at “Dr. Ignacio Morones Prieto” Central Hospital; here, the patients were examined using digital infrared thermal imaging. Patients in shock showed a significant decrease in distal temperature (at least 7°), compared to critically ill patients without shock. The latter group presented a skin temperature pattern very similar to the one previously reported for healthy children. The results show that infrared thermography can be used as a non-invasive method for monitoring the temperature in pediatric patients in intensive care units in order to detect shock in its early stages. PMID:27489669

  5. Achieving thermography with a thermal security camera using uncooled amorphous silicon microbolometer image sensors

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Wei; Tesdahl, Curtis; Owens, Jim; Dorn, David

    2012-06-01

    Advancements in uncooled microbolometer technology over the last several years have opened up many commercial applications which had been previously cost prohibitive. Thermal technology is no longer limited to the military and government market segments. One type of thermal sensor with low NETD which is available in the commercial market segment is the uncooled amorphous silicon (α-Si) microbolometer image sensor. Typical thermal security cameras focus on providing the best image quality by auto tonemaping (contrast enhancing) the image, which provides the best contrast depending on the temperature range of the scene. While this may provide enough information to detect objects and activities, there are further benefits of being able to estimate the actual object temperatures in a scene. This thermographic ability can provide functionality beyond typical security cameras by being able to monitor processes. Example applications of thermography[2] with thermal camera include: monitoring electrical circuits, industrial machinery, building thermal leaks, oil/gas pipelines, power substations, etc...[3][5] This paper discusses the methodology of estimating object temperatures by characterizing/calibrating different components inside a thermal camera utilizing an uncooled amorphous silicon microbolometer image sensor. Plots of system performance across camera operating temperatures will be shown.

  6. The Use of Infrared Thermography for Porosity Assessment of Intact Rock

    NASA Astrophysics Data System (ADS)

    Mineo, S.; Pappalardo, G.

    2016-08-01

    Preliminary results on a new test for the indirect assessment of porosity through infrared thermography are presented. The study of the cooling behavior of rock samples in laboratory, through the analysis of thermograms, proved an innovative tool for the estimation of such an important property, which is one of the main features affecting the mechanical behavior of rocks. A detailed experimentation was performed on artificially heated volcanic rock samples characterized by different porosity values. The cooling trend was described both graphically and numerically, with the help of cooling curves and Cooling Rate Index. The latter, which proved strictly linked to porosity, was employed to find reliable equations for its indirect estimation. Simple and multiple regression analyses returned satisfactory outcomes, highlighting the great match between predicted and measured porosity values, thus confirming the goodness of the proposed model. This study brings a novelty in rock mechanics, laying the foundation for future researches aimed at refining achieved results for the validation of the model in a larger scale.

  7. The roles of vibration analysis and infrared thermography in monitoring air-handling equipment

    NASA Astrophysics Data System (ADS)

    Wurzbach, Richard N.

    2003-04-01

    Industrial and commercial building equipment maintenance has not historically been targeted for implementation of PdM programs. The focus instead has been on manufacturing, aerospace and energy industries where production interruption has significant cost implications. As cost-effectiveness becomes more pervasive in corporate culture, even office space and labor activities housed in large facilities are being scrutinized for cost-cutting measures. When the maintenance costs for these facilities are reviewed, PdM can be considered for improving the reliability of the building temperature regulation, and reduction of maintenance repair costs. An optimized program to direct maintenance resources toward a cost effective and pro-active management of the facility can result in reduced operating budgets, and greater occupant satisfaction. A large majority of the significant rotating machinery in a large building environment are belt-driven air handling units. These machines are often poorly designed or utilized within the facility. As a result, the maintenance staff typically find themselves scrambling to replace belts and bearings, going from one failure to another. Instead of the reactive-mode maintenance, some progressive and critical institutions are adopting predictive and proactive technologies of infrared thermography and vibration analysis. Together, these technologies can be used to identify design and installation problems, that when corrected, significantly reduce maintenance and increase reliability. For critical building use, such as laboratories, research facilities, and other high value non-industrial settings, the cost-benefits of more reliable machinery can contribute significantly to the operational success.

  8. Automatic detection of diabetic foot complications with infrared thermography by asymmetric analysis

    NASA Astrophysics Data System (ADS)

    Liu, Chanjuan; van Netten, Jaap J.; van Baal, Jeff G.; Bus, Sicco A.; van der Heijden, Ferdi

    2015-02-01

    Early identification of diabetic foot complications and their precursors is essential in preventing their devastating consequences, such as foot infection and amputation. Frequent, automatic risk assessment by an intelligent telemedicine system might be feasible and cost effective. Infrared thermography is a promising modality for such a system. The temperature differences between corresponding areas on contralateral feet are the clinically significant parameters. This asymmetric analysis is hindered by (1) foot segmentation errors, especially when the foot temperature and the ambient temperature are comparable, and by (2) different shapes and sizes between contralateral feet due to deformities or minor amputations. To circumvent the first problem, we used a color image and a thermal image acquired synchronously. Foot regions, detected in the color image, were rigidly registered to the thermal image. This resulted in 97.8%±1.1% sensitivity and 98.4%±0.5% specificity over 76 high-risk diabetic patients with manual annotation as a reference. Nonrigid landmark-based registration with B-splines solved the second problem. Corresponding points in the two feet could be found regardless of the shapes and sizes of the feet. With that, the temperature difference of the left and right feet could be obtained.

  9. AN EVALUATION OF INFRARED THERMOGRAPHY FOR DETECTION OF BUMBLEFOOT (PODODERMATITIS) IN PENGUINS.

    PubMed

    Duncan, Ann E; Torgerson-White, Lauri L; Allard, Stephanie M; Schneider, Tom

    2016-06-01

    The objective of this study was to evaluate infrared thermography as a noninvasive screening tool for detection of pododermatitis during the developing and active stages of disease in three species of penguins: king penguin (Aptenodytes patagonicus) , macaroni penguin (Eudyptes chrysolophus), and rockhopper penguin (Eudyptes chrysocome). In total, 67 penguins were examined every 3 mo over a 15-mo period. At each exam, bumblefoot lesions were characterized and measured, and a timed series of thermal images were collected over a 4-min period. Three different methods were compared for analysis of thermograms. Feet with active lesions that compromise the surface of the foot were compared to feet with inactive lesions and no lesions. The hypothesis was that feet with active lesions would have warmer surface temperatures than the other conditions. Analysis of the data showed that although feet with active bumblefoot lesions are warmer than feet with inactive or no lesions, the variability seen in each individual penguin from one exam day to the next and the overlap seen between temperatures from each condition made thermal imaging an unreliable tool for detection of bumblefoot in the species studied. PMID:27468019

  10. Infrared thermography coupled with digital image correlation in studying plastic deformation on the mesoscale level

    NASA Astrophysics Data System (ADS)

    Wang, Xiaogang; Witz, Jean-François; El Bartali, Ahmed; Jiang, Chao

    2016-11-01

    This paper focuses on a study of plastic deformation on the mesoscale level by infrared thermography coupled with digital image correlation. First, a novel technique for fully-coupled thermal and kinematic measurements was developed, and the common problem of spatial coupling in the multifield measurement was solved successfully using an image registration method. Then the developed technique was applied to investigate the plastic deformation of a pure aluminium oligocrystal specimen in a tensile test. The deformed specimen manifested high strains of type out-of-plane, which were found closely associated with the crystallographic structure. From a metrological point of view, the out-of-plane effect on the thermographic measurement was analyzed, and the pertinent radiometric artifacts were estimated. The source of errors was verified through a correlation analysis between the estimated artifacts and specimen surface profile. Moreover, the out-of-plane effect on the kinematic measurement was investigated, and the relevant errors were analyzed via the correlation residual. The analysis highlighted the role of the microstructure that played in the plastic deformation and showed that grain boundary was crucial in shaping the heterogeneous deformation patterns for aluminium oligocrystals.

  11. Vibration characteristics measurement of beam-like structures using infrared thermography

    NASA Astrophysics Data System (ADS)

    Talai, S. M.; Desai, D. A.; Heyns, P. S.

    2016-11-01

    Infrared thermography (IRT) has matured and is now widely accepted as a condition monitoring tool where temperature is measured in a non-contact way. Since the late 1970s, it has been extensively used in vibrothermography (Sonic IR) non-destructive technique for the evaluation of surface cracks through the observation of thermal imaging of the vibration-induced crack heat generation. However, it has not received research attention on prediction of structural vibration behaviour, hence; the concept to date is not understood. Therefore, this paper explores its ability to fill the existing knowledge gap. To achieve this, two cantilever beam-like structures couple with a friction rod subjected to a forced excitations while infrared cameras capturing the thermal images on the friction interfaces. The analysed frictional temperature evolution using the Matlab Fast Fourier Transform (FFT) algorithm and the use of the heat conduction equation in conjunction with a finite difference approach successfully identifies the structural vibration characteristics; with maximum error of 0.28% and 20.71% for frequencies and displacements, respectively. These findings are particularly useful in overcoming many limitations inherent in some of the current vibration measuring techniques applied in structural integrity management such as strain gauge failures due to fatigue.

  12. Frescoes diagnostic using laser Doppler vibrometry and infrared thermography: experimental and numerical approaches

    NASA Astrophysics Data System (ADS)

    Agnani, Alexia; De Andrade, Roberto M.; Esposito, Enrico; Feligiotti, Mara; Tavares, Sinthya G.

    2006-06-01

    In this work laser Doppler vibrometry has been used for damage detection in frescoes. Results were compared with the ones obtained through infrared thermography, and, for both techniques, mathematical models were implemented to simulate the physical domains and conditions of the employed test sample. The limitations of each methodology are also discussed. The numerical model of the vibrometric investigations has been constructed using Finite Elements Method modeling. A new procedure based on the observation of Rayleigh waves propagation velocities allowed to acquire sample mechanical parameters. Comparison of experimental and simulated data and independent defect diameter measurement by echographic equipment, allowed to establish the confidence level and the discrepancies in the developed model. Also operational limits of the vibrometric technique have been studied by acquisition of Signal-to-Noise ratio on different areas of a sample. The Fourier equation has been used for the mathematical model employed for the numerical simulation of the thermographic investigations. Numerical technique with formularization in finite volumes has been employed and a FORTRAN code has been developed to solve the thermal problem.

  13. Differential infrared thermography for boundary layer transition detection on pitching rotor blade models

    NASA Astrophysics Data System (ADS)

    Raffel, Markus; Merz, Christoph B.; Schwermer, Till; Richter, Kai

    2015-02-01

    Differential infrared thermography (DIT) was investigated and applied for the detection of unsteady boundary layer transition locations on a pitching airfoil and on a rotating blade under cyclic pitch. DIT is based on image intensity differences between two successively recorded infrared images. The images were recorded with a high framing rate infrared camera. A pitching NACA0012 airfoil served as the first test object. The recorded images were used in order to investigate and to further improve evaluation strategies for periodically moving boundary layer transition lines. The measurement results are compared with the results of unsteady CFD simulations based on the DLR-TAU code. DIT was then used for the first time for the optical measurement of unsteady transition locations on helicopter rotor blade models under cyclic pitch and rotation. Image de-rotation for tracking the blade was employed using a rotating mirror to increase exposure time without causing motion blur. The paper describes the challenges that occurred during the recording and evaluation of the data in detail. However, the results were found to be encouraging to further improve the method toward the measurement of unsteady boundary layer transition lines on helicopter rotor models in forward flight.

  14. A Quantitative Investigation of Surface Roughness Effects on Airfoil Boundary Layer Transition Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Beeby, Todd Daniel

    An investigation of the impact of subcritical leading edge distributed roughness elements on airfoil boundary layer transition location has been undertaken using infrared thermography. In particular, a quantitative approach to boundary layer transition location detection using a differential energy balance method was implemented using a heating pad to produce constant heat flux. This was performed on a S809 airfoil model at Re c = 0.75 and 1.0 x 106, using roughness elements of height k/c = 3.75, 4.25 and 5.00 x 10 --4, pattern densities of 2 to 10 %, and roughness locations of 1 to 6 % chord. Turbulator tape of height k/c = 6.67 x 10--4 was also examined. Results indicate significant impact on transition for all roughness cases, and a more pronounced influence of roughness density as compared to roughness element height. The phenomenon of early laminar bubble collapse was also found to occur for some roughness configurations. The quantitative method used was found to be an effective means for automated transition location determination.

  15. Feasibility of using line scanning thermography in NDE of wind turbine blades

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Godinez, Valery

    2011-04-01

    Today, the increasing energy demand and the need for clean power generation has lead to the improvement of wind turbines and the development non invasive inspection techniques for the assessment of wind turbine blades to maintain long term reliability as well as to avoid catastrophic failures. Given the complexity of the geometry, the material composition and material thicknesses, finding a NDT technique to effectively and rapidly inspect the blades is a challenging task. Wind turbine blades are fabricated using different materials like fiber glass, carbon composites, foam and/ or balsa wood. Layers of these materials are bonded together using an epoxy type resin. Inspection of the bond quality between external layers and structural elements of the blade is of fundamental importance for quality control and service of the blade. In this study our efforts towards the applications of Line Scanning Thermography (LST) for the analysis of test coupons fabricated using the materials employed in the manufacture of wind turbine blades, as well as some wind turbine blade sections. LST utilizes a line heat source to thermally excite the surface to be inspected and an infrared detector to record the transient surface temperature variation produced by disbonds, and other subsurface imperfections. The LST technique has provided a quick and efficient methodology to scan large composite structures, which makes it desirable for the inspection of wind turbine blades. The scanning protocols developed for the detection of sub-surface disbonds (delamination) in coupons and parts will be presented. The successes and limitations of the technique will be discussed.

  16. Soft, thin skin-mounted power management systems and their use in wireless thermography.

    PubMed

    Lee, Jung Woo; Xu, Renxiao; Lee, Seungmin; Jang, Kyung-In; Yang, Yichen; Banks, Anthony; Yu, Ki Jun; Kim, Jeonghyun; Xu, Sheng; Ma, Siyi; Jang, Sung Woo; Won, Phillip; Li, Yuhang; Kim, Bong Hoon; Choe, Jo Young; Huh, Soojeong; Kwon, Yong Ho; Huang, Yonggang; Paik, Ungyu; Rogers, John A

    2016-05-31

    Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios. PMID:27185907

  17. Appreciation of the traffic effects on the RST by infrared thermography

    NASA Astrophysics Data System (ADS)

    Khalifa, Abderrahmen; Marchetti, Mario; Buès, Michel

    2014-09-01

    Road surface temperature forecast is a key component of winter maintenance strategy in many developed countries. Numerical tools exist to help road managers to organize services and consequently to trigger de-icing operations. Forecasting strategies have been commonplace since the 1980s, and often based on numerical models. Traffic is one of the influencing parameters, specifically in urban areas. This work was undertaken to evaluate to which extent an accurate description of traffic might improve numerical model dedicated to road surface temperature forecasting. Two sets of experiments were run to detect and to quantify traffic effects on RST. First one consisted in driving above an infrared radiometer, a pyrgeometer and other atmospheric probes to measure the radiative contribution of a passing vehicle at various speeds. In the second set, an infrared camera was installed on a vehicle in an urban traffic flow. This camera was mounted on the roof and focused the pavement right behind the vehicle ahead, both circulating at the same speed. Infrared thermography indicated a fleeting contribution of traffic to RST. The temperature increase in circulated areas, with respect to uncirculated ones, does not last according to collected measurements. Measurements with atmospheric and radiometric probes provided elements to properly take into account traffic in a numerical model and to appreciate its contribution.

  18. Soft, thin skin-mounted power management systems and their use in wireless thermography.

    PubMed

    Lee, Jung Woo; Xu, Renxiao; Lee, Seungmin; Jang, Kyung-In; Yang, Yichen; Banks, Anthony; Yu, Ki Jun; Kim, Jeonghyun; Xu, Sheng; Ma, Siyi; Jang, Sung Woo; Won, Phillip; Li, Yuhang; Kim, Bong Hoon; Choe, Jo Young; Huh, Soojeong; Kwon, Yong Ho; Huang, Yonggang; Paik, Ungyu; Rogers, John A

    2016-05-31

    Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios.

  19. Investigation of factors affecting backside hotspot localization in infrared lock-in thermography

    NASA Astrophysics Data System (ADS)

    Koh, Nicholas Chiu Yen; Sim, Kok Swee; Hoe, Tiong Min

    2015-07-01

    Infrared lock-in thermography (IR-LIT) is a fault localization technique that serves the purpose of detecting a local heat source or hotspot emitted by the faulty area. Performing backside hotspot localization overcomes the limitation during frontside hotspot localization, especially for shorted areas that emit a low heat source. In order to produce better hotspot localization from the package backside, it is important to study more of the factors affecting backside hotspot localization, including the power settings of the device, the lock-in frequency, and the die thickness of the packages. Power packages are inspected using a tool with varying power and frequency settings. The results are collected by observing the size of the hotspot and by recording the time taken for the hotspot to appear. To investigate the die thickness, the die surface is grinded from the backside of the die and the thickness of the die was measured using x-rays. The relationship between the power settings, the frequency settings, and the die thickness does show significant changes to the hotspot size and the time taken to generate a hotspot.

  20. Real-time quantification of viable bacteria in liquid medium using infrared thermography

    NASA Astrophysics Data System (ADS)

    Salaimeh, Ahmad A.; Campion, Jeffrey J.; Gharaibeh, Belal Y.; Evans, Martin E.; Saito, Kozo

    2011-11-01

    Quantifying viable bacteria in liquids is important in environmental, food processing, manufacturing, and medical applications. Since vegetative bacteria generate heat as a result of biochemical reactions associated with cellular functions, thermal sensing techniques, including infrared thermography (IRT), have been used to detect viable cells in biologic samples. We developed a novel method that extends the dynamic range and improves the sensitivity of bacterial quantification by IRT. The approach uses IRT video, thermodynamics laws, and heat transfer mechanisms to directly measure, in real-time, the amount of energy lost as heat from the surface of a liquid sample containing bacteria when the specimen cools to a lower temperature over 2 min. We show that the Energy Content ( EC) of liquid media containing as few as 120 colony-forming units (CFU) of Escherichia coli per ml was significantly higher than that of sterile media ( P < 0.0001), and that EC and viable counts were strongly positively correlated ( r = 0.986) over a range of 120 to approximately 5 × 10 8 CFU/ml. Our IRT approach is a unique non-contact method that provides real-time bacterial enumeration over a wide dynamic range without the need for sample concentration, modification, or destruction. The approach could be adapted to quantify other living cells in a liquid milieu and has the potential for automation and high throughput.

  1. Soft, thin skin-mounted power management systems and their use in wireless thermography

    PubMed Central

    Lee, Jung Woo; Xu, Renxiao; Lee, Seungmin; Jang, Kyung-In; Yang, Yichen; Banks, Anthony; Yu, Ki Jun; Kim, Jeonghyun; Xu, Sheng; Ma, Siyi; Jang, Sung Woo; Won, Phillip; Li, Yuhang; Kim, Bong Hoon; Choe, Jo Young; Huh, Soojeong; Kwon, Yong Ho; Huang, Yonggang; Paik, Ungyu; Rogers, John A.

    2016-01-01

    Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios. PMID:27185907

  2. Precise Temperature Mapping of GaN-Based LEDs by Quantitative Infrared Micro-Thermography

    PubMed Central

    Chang, Ki Soo; Yang, Sun Choel; Kim, Jae-Young; Kook, Myung Ho; Ryu, Seon Young; Choi, Hae Young; Kim, Geon Hee

    2012-01-01

    A method of measuring the precise temperature distribution of GaN-based light-emitting diodes (LEDs) by quantitative infrared micro-thermography is reported. To reduce the calibration error, the same measuring conditions were used for both calibration and thermal imaging; calibration was conducted on a highly emissive black-painted area on a dummy sapphire wafer loaded near the LED wafer on a thermoelectric cooler mount. We used infrared thermal radiation images of the black-painted area on the dummy wafer and an unbiased LED wafer at two different temperatures to determine the factors that degrade the accuracy of temperature measurement, i.e., the non-uniform response of the instrument, superimposed offset radiation, reflected radiation, and emissivity map of the LED surface. By correcting these factors from the measured infrared thermal radiation images of biased LEDs, we determined a precise absolute temperature image. Consequently, we could observe from where the local self-heat emerges and how it distributes on the emitting area of the LEDs. The experimental results demonstrated that highly localized self-heating and a remarkable temperature gradient, which are detrimental to LED performance and reliability, arise near the p-contact edge of the LED surface at high injection levels owing to the current crowding effect. PMID:22666050

  3. Infrared thermography of transition due to isolated roughness elements in hypersonic flows

    NASA Astrophysics Data System (ADS)

    Avallone, F.; Schrijer, F. F. J.; Cardone, G.

    2016-02-01

    Boundary layer transition in high-speed flows is a phenomenon that despite extensive research over the years is still extremely hard to predict. The presence of protrusions or gaps can lead to an accelerated laminar-to-turbulent transition enhancing the thermal loads and the skin friction coefficient. In the current investigation, inverse heat transfer measurements using infrared thermography are performed on the flow past different roughness geometries in the form of cylinders and diamond at free stream Mach number equal to 7.5, h/δ ranging between 0.5 and 0.9 (where h is the roughness height and δ is the boundary layer thickness), and Reθ ranging between 1305 and 2450. The roughness elements are positioned on a 5° ramp placed at zero angle of attack. The measurements indicate that the roughness geometry influences the transitional pattern while the frontal area influences both the transition location and the maximum value of the Stanton number along the centreline. Moreover, there is a strong connection between the streamwise centreline Stanton number and the spreading of the wake width. In particular, the transition process is characterized by an approximately constant wake width. Differently, the wake width spreads at the location where the streamwise centreline Stanton number reaches the turbulent level. This point corresponds to a local maximum of the wake amplitude defined as one half of the maximum spanwise variation of the Stanton number.

  4. Automatic detection of diabetic foot complications with infrared thermography by asymmetric analysis.

    PubMed

    Liu, Chanjuan; van Netten, Jaap J; van Baal, Jeff G; Bus, Sicco A; van der Heijden, Ferdi

    2015-02-01

    Early identification of diabetic foot complications and their precursors is essential in preventing their devastating consequences, such as foot infection and amputation. Frequent, automatic risk assessment by an intelligent telemedicine system might be feasible and cost effective. Infrared thermography is a promising modality for such a system. The temperature differences between corresponding areas on contralateral feet are the clinically significant parameters. This asymmetric analysis is hindered by (1) foot segmentation errors, especially when the foot temperature and the ambient temperature are comparable, and by (2) different shapes and sizes between contralateral feet due to deformities or minor amputations. To circumvent the first problem, we used a color image and a thermal image acquired synchronously. Foot regions, detected in the color image, were rigidly registered to the thermal image. This resulted in 97.8% ± 1.1% sensitivity and 98.4% ± 0.5% specificity over 76 high-risk diabetic patients with manual annotation as a reference. Nonrigid landmark-based registration with B-splines solved the second problem. Corresponding points in the two feet could be found regardless of the shapes and sizes of the feet. With that, the temperature difference of the left and right feet could be obtained.

  5. Experimental Heat Transfer Study of Endwall in a Linear Cascade with IR Thermography

    NASA Astrophysics Data System (ADS)

    Rojo, Borja; Jimenez, Carlos; Chernoray, Valery

    2014-03-01

    This abstract presents an endwall heat transfer experimental data of air flow going through outlet guide vanes (OGVs) situated in a low speed linear cascade. The measurement technique for this experiment was infrared thermography. In order to calculate the heat transfer coefficient (HTC) on the endwall, it has been used an instrumented window with a controlled constant temperature in one side of a 5 millimeter Plexiglass in order to generate high temperature gradients and, therefore, by measuring the surface temperature one the other side of the Plexiglass, it is calculated the HTC. Due to the fact that Plexiglass material has not good optical properties at infrared spectrum, it has been used a thin layer of black paint (10-12 μm) which has high emissivity (0.973) in the range of temperature that we are working. The Reynolds number for this experiment is 300000 in on and off-design configuration of the OGVs (on-design 25° and off-design cases are 40° and -25° incident angle). Furthermore, the on-design case is run at two different Reynolds number, 300000 and 450000. During this experiments it can be seen how changing the inlet angle to the OGVs produces significant differences on the heat transfer along the endwall. The main objective for this investigation is to study the heat transfer along the endwall of a linear cascade so that it would be a well-defined test case for CFD validation.

  6. Use of infrared thermography in children with shock: A case series.

    PubMed

    Ortiz-Dosal, Alejandra; Kolosovas-Machuca, Eleazar S; Rivera-Vega, Rosalina; Simón, Jorge; González, Francisco J

    2014-01-01

    Shock is a complex clinical syndrome caused by an acute failure of circulatory function resulting in inadequate tissue and organ perfusion. Digital infrared thermal imaging is a non-invasive technique that can detect changes in blood perfusion by detecting small changes in the temperature of the skin. In this preliminary study, eight pediatric patients (five boys, three girls), ages ranging from 6 to 14 years (average: 9.8 years), were admitted to the Intensive Care Unit at "Dr. Ignacio Morones Prieto" Central Hospital; here, the patients were examined using digital infrared thermal imaging. Patients in shock showed a significant decrease in distal temperature (at least 7°), compared to critically ill patients without shock. The latter group presented a skin temperature pattern very similar to the one previously reported for healthy children. The results show that infrared thermography can be used as a non-invasive method for monitoring the temperature in pediatric patients in intensive care units in order to detect shock in its early stages.

  7. Real Time Detection of Defects in GFRP Bridge Decks Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Klinkhachorn, P.; Lonkar, G. M.; Halabe, Udaya B.; GangaRao, Hota V. S.

    2006-03-01

    This work is aimed at building a real time system to detect subsurface defects in GFRP bridge decks using infrared thermography. The issues addressed are: (a) development of a real time defect detection system, and (b) image mosaicking to build a composite image map. In the tests conducted, a turn key system was built in Matlab environment using the FLIR SDK to acquire image from the ThermaCAM S60 infrared camera. The images were then analyzed by defect detection algorithms. Efforts were made to minimize the time to detect defects in a captured image. In the second phase, image mosaicking was used to build a "composite image" that combines all the infrared images to form a single image. The location of defects in the "composite image" leads to a system that will be able to point out defects in the bridge as a whole. The study creates a base that can be used for real time defect detection in GFRP bridge decks.

  8. AN EVALUATION OF INFRARED THERMOGRAPHY FOR DETECTION OF BUMBLEFOOT (PODODERMATITIS) IN PENGUINS.

    PubMed

    Duncan, Ann E; Torgerson-White, Lauri L; Allard, Stephanie M; Schneider, Tom

    2016-06-01

    The objective of this study was to evaluate infrared thermography as a noninvasive screening tool for detection of pododermatitis during the developing and active stages of disease in three species of penguins: king penguin (Aptenodytes patagonicus) , macaroni penguin (Eudyptes chrysolophus), and rockhopper penguin (Eudyptes chrysocome). In total, 67 penguins were examined every 3 mo over a 15-mo period. At each exam, bumblefoot lesions were characterized and measured, and a timed series of thermal images were collected over a 4-min period. Three different methods were compared for analysis of thermograms. Feet with active lesions that compromise the surface of the foot were compared to feet with inactive lesions and no lesions. The hypothesis was that feet with active lesions would have warmer surface temperatures than the other conditions. Analysis of the data showed that although feet with active bumblefoot lesions are warmer than feet with inactive or no lesions, the variability seen in each individual penguin from one exam day to the next and the overlap seen between temperatures from each condition made thermal imaging an unreliable tool for detection of bumblefoot in the species studied.

  9. Soft, thin skin-mounted power management systems and their use in wireless thermography

    NASA Astrophysics Data System (ADS)

    Lee, Jung Woo; Xu, Renxiao; Lee, Seungmin; Jang, Kyung-In; Yang, Yichen; Banks, Anthony; Yu, Ki Jun; Kim, Jeonghyun; Xu, Sheng; Ma, Siyi; Jang, Sung Woo; Won, Phillip; Li, Yuhang; Kim, Bong Hoon; Choe, Jo Young; Huh, Soojeong; Kwon, Yong Ho; Huang, Yonggang; Paik, Ungyu; Rogers, John A.

    2016-05-01

    Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios.

  10. Classification of factors influencing the use of infrared thermography in humans: A review

    NASA Astrophysics Data System (ADS)

    Fernández-Cuevas, Ismael; Bouzas Marins, Joao Carlos; Arnáiz Lastras, Javier; Gómez Carmona, Pedro María; Piñonosa Cano, Sergio; García-Concepción, Miguel Ángel; Sillero-Quintana, Manuel

    2015-07-01

    Body temperature is one of the most commonly used indicators of health status in humans. Infrared thermography (IRT) is a safe, non-invasive and low-cost technique that allows for the rapid and non-invasive recording of radiating energy that is released from the body. IRT measures this radiation, directly related to skin temperature (Tsk) and has been widely used since the early 1960s in different areas. Recent technical advances in infrared cameras have made new human applications of IRT (beyond diagnostic techniques) possible. This review focuses on the lack of comprehensive information about the factors influencing the use of IRT in humans, and proposes a comprehensive classification in three primary groups: environmental, individual and technical factors. We aim: to propose a common framework for further investigations; to reinforce the accuracy of human IRT; to summarise and discuss the results from the studies carried out on each factor and to identify areas requiring further research to determine their effects on human IRT.

  11. Using lock-in infrared thermography for the visualization of the hand vascular tree

    NASA Astrophysics Data System (ADS)

    Bouzida, Nabila; Bendada, Abdel Hakim; Piau, Jean-Marc; Akhloufi, Moulay; Maldague, Xavier; Raymond, Mathieu

    2008-03-01

    An imaging technique of the hand vein tree is presented in this paper. Using the natural human circulatory system and a controlled armband pressure around the arm, a lock-in thermography technique with an internal excitation is carried out. Since the stimulation frequency is inversely proportional to the inspection depth, the subcutaneous layer requires the use of a very slow frequency. Thus, a sawtooth waveform is preferred to minimize the duration of the pressure applied to the armband during the experiment. A frequency of approximately 0.03 Hz and a pressure range between 100 and 140 mmHg, according to the diastolic and systolic blood pressure, are used as stimulation. Then, dorsal hand amplitude and phase images are obtained with IR_view (Klein, 1999), a tool specifically designed to analyze infrared images. The hand vein structure is thermally mapped by an infrared camera operating in the middle wavelength infrared range (MWIR) at room temperature. Parasitic frequencies are avoided by keeping the hand fixed. The resulting images show a gradient of temperature between surrounding tissues and the back-of-hand veins. The vascular signature segmentation is extracted from the amplitude and phase images by using a Fast Fourier Transform image processing technique. This work could be used for vein localization for perfusion or for the early diagnosis of vein diseases such as primitive varicose and deep vein thrombosis (DVT). A hand vein signature database for identification purposes is also possible.

  12. Classification of electrical problems detected by infrared thermography using a risk assessment process

    NASA Astrophysics Data System (ADS)

    McIntosh, Gregory B.; Huff, Roy

    2016-05-01

    For more than 40 years thermography has been used for electrical problem detection. In addition, since radiometric infrared cameras can establish apparent surface temperature of the problem, a classification system is often utilized based upon surface temperature, or temperature rise above normal operating temperature or ambient air temperature. This however can be an extremely unreliable classification method for a number of reasons including: emissivity and background energy; a lack of regard for failure modes and stressors; surface temperature variability with load and ambient conditions; temperature gradient from internal source to surface; and the presence of convection, just to name a few. Standards, such as NFPA 70B, try to address some of these issues by having very low threshold temperature limits, but this as well has issues including identifying an over-abundance of non-critical problems for immediate repair. This paper will present a risk assessment process and matrix which classifies electrical problems based upon a variety of factors affecting both probability and consequence of electrical component failure. Inherent in this process will be a discussion of understanding and analysing electrical connection failure modes and failure stressors, as well as consideration of both heat energy flow and stored energy rather than only considering surface temperature as a single point predictor of catastrophic failure.

  13. Precise temperature mapping of GaN-based LEDs by quantitative infrared micro-thermography.

    PubMed

    Chang, Ki Soo; Yang, Sun Choel; Kim, Jae-Young; Kook, Myung Ho; Ryu, Seon Young; Choi, Hae Young; Kim, Geon Hee

    2012-01-01

    A method of measuring the precise temperature distribution of GaN-based light-emitting diodes (LEDs) by quantitative infrared micro-thermography is reported. To reduce the calibration error, the same measuring conditions were used for both calibration and thermal imaging; calibration was conducted on a highly emissive black-painted area on a dummy sapphire wafer loaded near the LED wafer on a thermoelectric cooler mount. We used infrared thermal radiation images of the black-painted area on the dummy wafer and an unbiased LED wafer at two different temperatures to determine the factors that degrade the accuracy of temperature measurement, i.e., the non-uniform response of the instrument, superimposed offset radiation, reflected radiation, and emissivity map of the LED surface. By correcting these factors from the measured infrared thermal radiation images of biased LEDs, we determined a precise absolute temperature image. Consequently, we could observe from where the local self-heat emerges and how it distributes on the emitting area of the LEDs. The experimental results demonstrated that highly localized self-heating and a remarkable temperature gradient, which are detrimental to LED performance and reliability, arise near the p-contact edge of the LED surface at high injection levels owing to the current crowding effect.

  14. Non-destructive inspection of drilled holes in reinforced honeycomb sandwich panels using active thermography

    NASA Astrophysics Data System (ADS)

    Usamentiaga, R.; Venegas, P.; Guerediaga, J.; Vega, L.; López, I.

    2012-11-01

    The aerospace industry is in constant need of ever-more efficient inspection methods for quality control. Product inspection is also essential to maintain the safe operation of aircraft components designed to perform for decades. This paper proposes a method for non-destructive inspection of drilled holes in reinforced honeycomb sandwich panels. Honeycomb sandwich panels are extensively employed in the aerospace industry due to their high strength and stiffness to weight ratios. In order to attach additional structures to them, panels are reinforced by filling honeycomb cells and drilling holes into the reinforced areas. The proposed procedure is designed to detect the position of the holes within the reinforced area and to provide a robust measurement of the distance between each hole and the boundary of the reinforced area. The result is a fast, safe and clean inspection method for drilled holes in reinforced honeycomb sandwich panels that can be used to robustly assess a possible displacement of the hole from the center of the reinforced area, which could have serious consequences. The proposed method is based on active infrared thermography, and uses state of the art methods for infrared image processing, including signal-to-nose ratio enhancement, hole detection and segmentation. Tests and comparison with X-ray inspections indicate that the proposed system meets production needs.

  15. Infrared thermography of evaporative fluxes and dynamics of salt deposition on heterogeneous porous surfaces

    NASA Astrophysics Data System (ADS)

    Nachshon, Uri; Shahraeeni, Ebrahim; Or, Dani; Dragila, Maria; Weisbrod, Noam

    2011-12-01

    Evaporation of saline solutions from porous media, common in arid areas, involves complex interactions between mass transport, energy exchange and phase transitions. We quantified evaporation of saline solutions from heterogeneous sand columns under constant hydraulic boundary conditions to focus on effects of salt precipitation on evaporation dynamics. Mass loss measurements and infrared thermography were used to quantify evaporation rates. The latter method enables quantification of spatial and temporal variability of salt precipitation to identify its dynamic effects on evaporation. Evaporation from columns filled with texturally-contrasting sand using different salt solutions revealed preferential salt precipitation within the fine textured domains. Salt precipitation reduced evaporation rates from the fine textured regions by nearly an order of magnitude. In contrast, low evaporation rates from coarse-textured regions (due to low capillary drive) exhibited less salt precipitation and consequently less evaporation rate suppression. Experiments provided insights into two new phenomena: (1) a distinct increase in evaporation rate at the onset of evaporation; and (2) a vapor pumping mechanism related to the presence of a salt crust over semidry media. Both phenomena are related to local vapor pressure gradients established between pore water and the surface salt crust. Comparison of two salts: NaCl and NaI, which tend to precipitate above the matrix surface and within matrix pores, respectively, shows a much stronger influence of NaCl on evaporation rate suppression. This disparity reflects the limited effect of NaI precipitation on matrix resistivity for solution and vapor flows.

  16. The use of infrared thermography to detect the skin temperature response to physical activity

    NASA Astrophysics Data System (ADS)

    Tanda, G.

    2015-11-01

    Physical activity has a noticeable effect on skin blood flow and temperature. The thermal regulatory and hemodynamic processes during physical activity are controlled by two conflicting mechanisms: the skin vasoconstriction induced by the blood flow demand to active muscles and the skin vasodilation required by thermoregulation to increase warm blood flow and heat conduction to the skin. The time-evolution of skin temperature during exercise can give useful information about the adaptation of the subject as a function of specific type, intensity and duration of exercise. In this paper, infrared thermography is used to investigate the thermal response of skin temperature during running exercise on treadmill for a group of seven healthy and trained runners. Two different treadmill exercises are considered: a graded load exercise and a constant load exercise; for both exercises the duration was 30 minutes. Within the limits due to the relatively small size of the sample group, results typically indicate a fall in skin temperature during the initial stage of running exercise. As the exercise progresses, the dynamics of the skin temperature response depends on the type of exercise (graded versus constant load) and probably on the level of training of the subject.

  17. Applications of infrared thermography for nondestructive testing of fatigue cracks in steel bridges

    NASA Astrophysics Data System (ADS)

    Sakagami, Takahide; Izumi, Yui; Kobayashi, Yoshihiro; Mizokami, Yoshiaki; Kawabata, Sunao

    2014-05-01

    In recent years, fatigue crack propagations in aged steel bridge which may lead to catastrophic structural failures have become a serious problem. For large-scale steel structures such as orthotropic steel decks in highway bridges, nondestructive inspection of deteriorations and fatigue damages are indispensable for securing their safety and for estimating their remaining strength. As conventional NDT techniques for steel bridges, visual testing, magnetic particle testing and ultrasonic testing have been commonly employed. However, these techniques are time- and labor- consuming techniques, because special equipment is required for inspection, such as scaffolding or a truck mount aerial work platform. In this paper, a new thermography NDT technique, which is based on temperature gap appeared on the surface of structural members due to thermal insulation effect of the crack, is developed for detection of fatigue cracks. The practicability of the developed technique is demonstrated by the field experiments for highway steel bridges in service. Detectable crack size and factors such as measurement time, season or spatial resolution which influence crack detectability are investigated.

  18. Line laser lock-in thermography for instantaneous imaging of cracks in semiconductor chips

    NASA Astrophysics Data System (ADS)

    An, Yun-Kyu; Yang, Jinyeol; Hwang, Soonkyu; Sohn, Hoon

    2015-10-01

    This study proposes a new line laser lock-in thermography (LLT) technique for instantaneous inspection of surface cracks in semiconductor chips. First, a new line LLT system is developed by integrating a line scanning laser source, a high-speed infrared (IR) camera with a close-up lens, and a control computer. The proposed line LLT system scans a line laser beam onto a target semiconductor chip surface and measures the corresponding thermal wave propagation using an IR camera. A novel baseline-free crack visualization algorithm is then proposed so that heat blocking phenomena caused by crack formation can be automatically visualized and diagnosed without relying on the baseline data obtained from the pristine condition of a target semiconductor chip. The proposed inspection technique offers the following advantages over the existing semiconductor chip inspection techniques: (1) inspection is performed in a noncontact, nondestructive and nonintrusive manner; (2) the crack diagnosis can be accomplished using only current-state thermal images and thus past thermal images are unnecessary; and (3) crack detectability is significantly enhanced by achieving high spatial resolution for thermal images and removing undesired noise components from the measured thermal images. Validation tests are performed on two different types of semiconductor die chips with real micro-cracks produced during actual fabrication processes. The experiments demonstrate that the proposed line LLT technique can successfully visualize and detect semiconductor chip cracks with width of 28-54 μm.

  19. Automating data analysis during the inspection of boiler tubes using line scanning thermography

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Momeni, Sepand; Ostroff, Jason; Godinez, Valery

    2012-05-01

    Failures in boiler waterwalls can occur when a relatively small amount of corrosion and loss of metal have been experienced. This study presents our efforts towards the application of Line Scanning Thermography (LST) for the analysis of thinning in boiler waterwall tubing. LST utilizes a line heat source to thermally excite the surface to be inspected and an infrared detector to record the transient surface temperature increase observed due to the presence of voids, thinning or other defects. In waterwall boiler tubes the defects that can be detected using LST correspond to corrosion pitting, hydrogen damage and wall thinning produced by inadequate burner heating or problems with the water chemistry. In this paper we discuss how the LST technique is implemented to determine thickness from the surface temperature data, and we describe our efforts towards developing a semiautomatic analysis tool to speed up the time between scanning, reporting and implementing repairs. We compare the density of data produced by the common techniques used to assess wall thickness and the data produced by LST.

  20. Acoustics in Schools.

    ERIC Educational Resources Information Center

    Singer, Miriam J.

    This paper explores the issues associated with poor acoustics within schools. Additionally, it suggests remedies for existing buildings and those under renovation, as well as concerns for new construction. The paper discusses the effects of unwanted noise on students in terms of physiological, motivational, and cognitive influences. Issues are…