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At least 379 records · Page 21Linked to original sources
PubMed2002

Convective heat transfer and infrared thermography.

Infrared (IR) thermography, because of its two-dimensional and non-intrusive nature, can be exploited in industrial applications as well as in research. This paper deals with measurement of convective heat transfer coefficients (h) in three complex fluid flow configurations that concern the main aspects of both internal and external cooling of turbine engine components: (1) flow in ribbed, or smooth, channels connected by a 180 degrees sharp turn, (2) a jet in cross-flow, and (3) a jet impinging on a wall. The aim of this study was to acquire detailed measurements of h distribution in complex flow configurations related to both internal and external cooling of turbine components. The heated thin foil technique, which involves the detection of surface temperature by means of an IR scanning radiometer, was exploited to measure h. Particle image velocimetry was also used in one of the configurations to precisely determine the velocity field.

Convection↗
PubMed1992

Microwave thermography: a non-invasive technique for investigation of injury of the superficial digital flexor tendon in the horse.

Microwave thermographs were recorded from 77 normal horses. In 51% the lowest temperature was recorded in the mid-metacarpal region, and in 41% it was in the distal metacarpal region. The mean temperature of the normal limbs ranged from 25.04 to 37.4 degrees C. Maximum temperature differences between symmetrical points in both forelimbs ranged from 0 to 5.33 degrees C and differences in mean limb temperatures between both forelimbs ranged from 0 to 2.91 degrees C. In 48 horses with acute (less than 4 weeks' duration) injury of the superficial digital flexor tendon (SDFT) (36 unilateral, 12 bilateral) and 12 horses with acute injury of the soft tissues of the palmar metacarpal region other than the SDFT (all unilateral) 66% of forelimbs had acute SDFT injury, and 50% of those with other soft tissue injuries, had elevations of the temperature in the mid- or distal metacarpal region. Abnormal values for mean limb temperature, difference in mean limb temperature and maximum temperature difference between locations in opposite forelimbs were detected in 75% of the horses with SDFT injury and in only 16% of the horses with other soft tissue injury. The sensitivity of microwave thermography for the detection of SDFT injury was 81% and the specificity 74%. When 30 horses in National Hunt training were examined weekly for 5 weeks, 2 horses sustained SDFT injury during that period. The microwave thermographs recorded from these 2 horses, at 1 and 2 weeks before the onset of clinical signs, were abnormal. However, 16 horses which did not develop tendon injury also displayed thermographic abnormalities.

Animals↗
PubMed1980

Neonatal skin temperature distribution using infra-red colour thermography.

1. Infra-red Colour Thermography was used to visualize skin temperatures over seven neonates nursed in a modified temperature controlled incubator. 2. Temperature distributions were recorded on cine film which was analysed to evaluate mean skin temperatures; these were subsequently compared with values obtained from multiple, weighted measurements from a thermocouple thermometer. In all cases, there was agreement to within +/- 0 . 6 degrees C. 3. Thermograms in thermo-neutral conditions (approximately 32 degrees C) showed a temperature distribution with the warmest skin overlying the central hot 'core' and temperatures falling towards the extremities. Temperature patterns in a cooler environment (approximately 28 degrees C) showed features due to the conductive or thermogenic nature of the structures underlying the skin. 4. Multiple skin temperature recordings made at two environmental temperatures were obtained from a further twelve infants. 5. Linear regression of skin temperature against rectal--environmental difference, performed for each of the measured sites, showed that the upper arm and, to a lesser extent, the upper thigh temperatures represented the mean value most closely. The upper abdomen and head were both warmer and less responsive to environmental change than the mean skin temperature. These findings were supported by the thermographic observations.

Humans↗
PubMedDate not supplied

Temperature mapping of laser-induced hyperthermia in an ocular phantom using magnetic resonance thermography.

Laser-induced heating in an ocular phantom is measured with magnetic resonance thermography (MRT) using temperature-dependent phase changes in proton resonance frequency. The ocular phantom contains a layer of melanosomes isolated from bovine retinal pigment epithelium. The phantom is heated by the 806-nm output of a continuous wave diode laser with an irradiance of 2.4 to 21.6 W/cm2 in a beam radius of 0.8 or 2.4 mm, depending on the experiment. MRT is performed with a 2 T magnet, and a two-turn, 6-cm-diam, circular radio frequency coil. Two-dimensional temperature gradients are measured within the plane of the melanin layer, as well as normal to it, with a temperature resolution of 1 degrees C or better. The temperature gradients extending within the melanin layer are broader than those orthogonal to the layer, consistent with the higher optical absorption and consequent heating in the melanin. The temperature gradients in the phantom measured by MRT closely approximate the predictions of a classical heat diffusion model. Three-dimensional temperature maps with a spatial resolution of 0.25 mm in all directions are also made. Although the temporal resolution is limited in the prototype system (22.9 s for a single image "slice"), improvements in future implementations are likely. These results indicate that MRT has sufficient spatial and temperature resolution to monitor target tissue temperature during transpupillary thermotherapy in the human eye.

Animals↗
PubMed1963

Thermography of the human body.

Human skin is an almost perfect emitter of infrared radiation in the spectral region beyond 3 microns. This energy may be recorded as a thermogram to yield a quantitative temperature map of the skin. If the nude subject has remained quiet in a cool room for 10 to 15 minutes prior to thermography, the skin temperatures are determined largely by the vascularity of the skin itself and by the heat conducted from within the body. Since, under these conditions, the contrasts which appear arise essentially from the internal sources of heat, the resulting thermograms yield information concerning certain pathological conditions within the body (16).

Hot Temperature↗
PubMed1972

Value of mammary thermography in differential diagnosis.

Thermographic examinations of the breasts were carried out in 359 women, most of whom had mammary symptoms. Of the 195 patients with abnormal thermograms, 27 had cancer of the breast, 53 had benign lesions, and 115 had no confirmed organic disease. The incidence of false-positive thermograms was 59%. Of the 164 patients with normal thermograms, 116 had no confirmed organic disease, 41 had benign lesions, and 7 had cancer. The incidence of false-negative mammary thermograms was 29%.We conclude that mammary thermography is of no practical value in the differential diagnosis of symptomatic mammary disease.

Breast Diseases↗
PubMed1989

Potential of infra-red thermography for the detection of summer seasonal recurrent dermatitis (sweet itch) in horses.

The feasibility of using infra-red thermography for early and out of season detection of summer seasonal recurrent dermatitis (sweet itch) was tested on 13 sensitive and six insensitive horses in Israel. In summer (June, July and September) six affected mares and two unaffected sensitive mares (one of them a pony) were clearly 'warmer' in the affected zones than three insensitive mares. In winter (February and March) unaffected sensitive horses could be differentiated from insensitive mares by the warm areas detected in the affected zones. Small numbers of Culicoides imicola bites may have been the cause of the local heat reactions of the body that were detected by the infra-red radiometer.

Animals↗
PubMed1976

Lumbar thermography in discogenic disease.

Thermography is a simple, noninvasive outpatient procedure which can be performed on patients with clinical symptoms of a herniated disk. A positive thermogram usually indicates that an abnormality will be found by myelography. However, the myelographic findings cannot be predicted by a negative lumbar thermogram.

Adolescent↗
PubMed1981

The potential value of liquid-crystal thermography in detecting significant mastopathy.

Liquid-crystal thermography (LCT) was assessed as a means of detecting proliferative disorders of the breast independently of other clinical or radiological data. There was no statistically significant difference between positive diagnosis rates for LCT of the breast in biopsy-proved proliferative disorders and in clinically and radiologically normal volunteers. While this experiment was not designed to evaluate LCT for detection or diagnosis of advanced, clinically occult, or minimal breast cancer, the data suggest that this technique can identify some large, bulky tumors, and that the smaller the lesion, the less likely that it would be detected by LCT.

Breast Neoplasms↗
PubMed1981

Amputation of the ischemic limb: selection of the optimum site by thermography.

This report describes the value of infrared thermography in assessing the optimum level of amputation of an ischemic limb. Interpretation of thermograms and the factors that can significantly alter the thermal image of the lower limbs are detailed. Results from 104 patients demonstrate that the thermographic method is a reliable indicator of the level of a major limb amputation. A rationale for the inadequacy of the method when attempting to determine the outcome of a partial foot amputation is considered.

Adult↗
PubMed1985

The noninvasive laboratory--history and future of thermography.

A brief history of thermography and recent developments in instrumentation have been reviewed. Important applications are related to thrombophlebitis, the cerebral circulation, peripheral arterial abnormalities and medical-legal situations.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Thermography in posttraumatic pain.

Posttraumatic pain is often associated with complex disturbances of the sympathetic nervous system which also controls microcirculation of the skin. Circulatory skin changes are in turn reflected by altered superficial thermal emission, which can be reliably imaged by thermography. Examples of classic thermographic patterns associated with commonly occurring injuries and detected along cutaneous distributions of peripheral nerves or spinal root dermatomes are presented. Thermographic abnormalities may also occur in ondermatomal distributions to involve an entire hand, foot, or extremity as observed in reflex sympathetic dystrophy. Such thermographic findings often appear before skin or roentgenographic changes become manifest and lead to earlier diagnosis. Prompt and more effective treatment, particularly in reflex sympathetic dystrophy, may thereby be initiated so that full blown, difficult to manage, chronic disability may be averted. The diagnosis of malingering may also be strengthened or suspected if thermographic studies together with other examinations are normal.

Adolescent↗
PubMed2003

Detection of gas leakage from landfills using infrared thermography--applicability and limitations.

Although landfill gas emission can be greatly reduced by extraction and converting gas to energy, in practice not all gas can be collected and some leaks can still occur. Management of landfill gas can be improved if leaks can be detected and rectified effectively. This paper provides a brief review of methods available for detecting landfill leakage, with a focus on infrared thermography. It then describes a study which was conducted to test if an infrared camera can be used to detect gas leaks accurately by identifying them as anomalies. It examined the applicability and limitations of the technique by investigating fundamental factors such as weather conditions, ground conditions and distance of sensor from source. The paper also describes a test case conducted to reinforce the findings. It concluded that unless all the fundamental factors are clearly understood and addressed, the technique currently can only be used as a screening tool rather than as a precise tool to detect landfill gas leakages. For this reason, it would be difficult to use the technique as a basis for modelling gas emission from landfills.

Air Pollutants↗
PubMed1977

Comparison of intra-articular methotrexate with intra-articular triamcinolone hexacetonide by thermography.

A comparison of intra-articular methotrexate and intra-articular triamcinolone hexacetonide was made in 42 arthritic patients with persistent bilateral knee effusions. One knee was injected with either 5 mg methotrexate (two injections of 2.5 mg a week apart) or a single injection of 20 mg triamcinolone. An objective assessment of both knees was made by quantitative thermography at 0,3,7,14 and 21 days. Joints injected with triamcinolone showed a greater fall in thermographic index (T.I) than the joints injected with methotrexate, which showed similar change to the non-injected knee joints in both groups. Four patients received larger doses of methotrexate, up to 20 mg, though the fall in T.I. was still less than the mean fall for triamcinolone injected joints. Peak venous blood levels of methotrexate were reached 1 hour after intra-articular injection, and a sphygmomanometer cuff inflated around the leg above the injected knee for periods of up to 1 hour did not appreciably delay this. Methotrexate had no immediate anti-inflammatory effect, even in psoriatic arthropathy, and did not give the relief of intra-articular steroid.

Adult↗
PubMed2005

Infrared thermography fails to visualize stimulation-induced meridian-like structures.

BACKGROUND: According to Traditional Chinese Medicine (TCM) the vital energy flows through a system of channels also called meridians. Generally accepted proof for meridians cannot be considered as being given. Goal of this study was to examine whether possible stimulation-induced meridian-like structures, as recently described by other authors, can be visualized and objectified simultaneously at different infrared wavelength ranges. METHODS: The study analyses evidence for the existence of acupuncture-specific, meridian-like artifacts in 6 healthy volunteers (mean age +/- SD 28.7 +/- 3.7 years; range 25 - 35 years). Two infrared cameras at different wavelength ranges were used for thermographic control of possible stimulation effects (moxibustion-cigar, infrared warmth stimulation, needle and laserneedle stimulation). In addition to thermography, temperature and microcirculatory parameters were registered at a selected point using laser-Doppler flowmetry. RESULTS AND CONCLUSION: After moxibustion (or infrared light stimulation) of the body at 2 - 5 microm and 7.5 - 13 microm ranges, different structures appear on thermographic images of the human body which are technical artifacts and which are not identical to what are known as meridians in all textbooks of TCM. Further scientific studies are required regarding the possible visualization of meridians.

Acupuncture Points↗
PubMed1994

Intraoperative regional and functional thermography during resection of cerebral arteriovenous malformation.

We present the first use of intraoperative thermographical imaging for the surgical resection of a cerebral arteriovenous malformation. For obtaining intraoperative regional and functional thermographical images, a real-time mode infrared camera was installed to an operating microscope with an exclusively developed attachment device. Changes of the surface temperature of the cortical draining vein and the surrounding cortical surface were observed intraoperatively before and after the occlusion of the main feeder. Intraoperative functional thermography with cold physiological saline solution demonstrated a change in the heat clearance of the draining vein after complete obliteration of the feeder.

Adult↗
PubMed1975

Thermography of the female breast: a five-year study in relation to the detection and prognosis of cancer.

More than 12,000 women have been examined thermographically in the Breast Unit of the Royal Marsden Hospital, London. Of these women 1,464 had biopsy and histology; 363(25 per cent) were found to have carcinoma and of these 68 per cent had abnormal thermograms, 13 per cent has some thermal asymmetry of doubtful significance and 19 per cent had normal thermal patterns. Fifty-seven per cent and 62 per cent of patients with Stage I and Stage II cancer, respectively, had abnormal thermograms whereas 83 per cent of patients with Stage III cancer had abnormal thermograms. Of 1,101 women who had benign lesions, 63 per cent had normal thermal patterns, 15 per cent had thermal asymmetry of doubtful significance and 22 per cent had abnormal thermograms. The subsequent histories of 172 cancer patients examined thermographically have been analysed and three-year survival rates have been correlated with thermography report, the clinical stage of the disease and the histotogical grade (Bloom, 1950) of the excised tumour. The mean three-year survival rates for patients with Stage II or Stage III cancer are 84 per cent for those with normal and 61 per cent for those with abnormal thermograms.

Adenofibroma↗