The use of finite element analysis for predicting surface temperatures in response to hidden features is presented. Examples of predicted temperatures for buried pipes using passive IR and for subsurface flaws using active IR are presented. The impact of various depths for the pipe and the flaw, as well as the size of the flaw are examined. The use of the approach to improve the likelihood of successful application of IR Thermography for problem solution is discussed. It is my purpose in this paper to acquaint those of you who are not aware of FEA's capabilities with those capabilities, and to demonstrate, in particular, two applications for it in the area of thermography. Many other applications are possible and I hope that the two cases presented will suggest some of them.

Comparison between analytical 1D and numerical 2D models is made to formulate recommendations on choosing temporal and spatial grid steps within numerical algorithms intended for solving thermal NDE problems. It is shown that accuracy in computing temperature is typically better than 10% in both sound and defect areas. Reference temperature evolutions are given for a few test situations.

In this paper, two neural network approaches are compared for defect detection using thermal evolution, phase and amplitude data acquired in the pulsed thermography approach with pulsed phase thermography processing. The tested approaches are based on Perceptron and Kohonen neural networks. Examples of results are presented for each technique with the three types of available data, in the case of flat-bottom holes in aluminum. Results show that the Perceptron using phase data gives better results being less influenced by disturbances.

A technique for enhanced defect visualization in composites via transient thermography is presented in this paper. The effort targets automated defect map construction for multiple defects located in the observed area. Experimental data were collected on composite panels of different thickness with square inclusions and flat bottom holes of different depth and orientation. The time evolution of the thermal response and spatial thermal profiles are analyzed. The pattern generated by carbon fibers and the vignetting effect of the focal plane array camera make defect visualization difficult. An improvement of the defect visibility is made by the pulse phase technique and the spatial background treatment. The relationship between a size of a defect and its reconstructed image is analyzed as well. The image processing technique for noise reduction is discussed.

A common problem found in advanced structural materials is water entrapment. This problem is a major cause of material degradation. In metals it can lead to corrosion and in composites it adds unnecessary weight to the structure and can lead to material degradation especially after freezing and thawing. Thermography has been investigated as a means of detection water entrapment in metallic structures. A simple model has been derived that accurately describes the thermal response of these structures to short heat pulses. In this paper results on Aluminum panels with various amounts of water entrapment will be presented. Sensitivity relations will be derived and validated.

High thermal conductivity carbon fibers are orthotropic, having significantly different properties in the longitudinal (650 - 1100 W/mK) and radial directions (15 - 50 W/mK). These fibers can function like thermal 'pipes' to directionally transport heat from one location to another. The potential of such high thermal conductivity materials to facilitate enhanced thermal management in miniaturized electronics systems used in space applications is considered. Visualization of heat flow using time-resolved infrared imaging and analysis of the capabilities of different fabricated structures for directing heat flow will be described.

We describe fast infrared imaging of both static and dynamic crush tests on glass-fiber composite tubes. The results are compared with video images of the same tests.

Development of nondestructive evaluation (NDE) methods for spot-welded and adhesive-bonded sheet metal joints is essential for widespread use of lightweight materials and new construction techniques in automotive applications. An important objective of research in progress is development of NDE methods to identify and characterize critical flaws in welded and adhesive-bonded joints. We used steady-state heat- flow and thermographic imaging techniques to test welded and adhesive-bonded lap joints in steel and aluminum samples and in adhesive-bonded composite panels and to identify defective spot welds. The resulting surface-temperature maps or thermograms were used to detect voids and areas where the adhesive was not bonded. To better characterize defects in welds and adhesive layers, algorithms have been developed to post process temperature data, producing more accurate definition of the geometry and location of defects than in previous images. Classic heat-transfer theory was used to calculate the heat-flux equilibrium for each individual pixel on the thermograms. Convective and radiative surface heat- transfer coefficients were applied to compensate for the heat exchange between the sample and the environment. This post processing permits us to determine the locations of spot welds and the sizes of the weld nuggets in welded joints, and to clearly image voids in adhesive layers between joints. The effectiveness of the image-processing algorithms was investigated using data from laboratory experiments on test specimens with flaws of known size and location. In addition, the images of the defects produced with the new method were compared to results of two-dimensional heat transfer simulations through the same samples. The simulations were also used to determine boundary conditions for post-processing of images.

Weak spots or damage areas in the thermal insulation of heat pipelines cause heat losses in district heating distribution systems. Especially, the sleeve joints are frequent leak sources. Traditional methods for testing the pipeline insulation require heating the whole heat pipeline after laying and are thus time consuming. In this paper we present a novel and simple method suitable for non-destructive quality control. The method may be applied during pipeline production. It also serves as a fast method for testing the sleeve joint directly after assembly, even in the case of a cold laying of the pipelines. The procedure only requires low-energy local heating in the test area which needs to be applied to the interior of the medium pipe. The method is based on a focal plane array thermal imaging system. The temperature distribution on the surface of the pipeline is imaged by the infrared camera after applying a heat pulse in the area under test. The camera used resolves temperature differences of the order of 10 mK, exhibits long-term calibration stability, and is robust for outdoor use. Damages of the insulation at a size down to a few cubic centimeters are resolved as 'hot spots' on the surface of the heat pipeline. The high sensitivity is achieved by dynamic measurements of the heat redistribution after applying the heat pulse. Images having an optimum contrast are usually observed with some delay (up to a few minutes) after the heat pulse. In the paper we will present numerical simulations of the leak detection and thus demonstrate the resolution. Examples of tests will be given.

In this paper the IR Microscopy Thermosensoric Defect Localization method ((mu) -TDL) is presented. This technique is based on a novel IR microscopy lens which permits to take IR images with a spatial resolution of better than 10 micrometer, which is close to the theoretical limit. The (mu) -TDL method is demonstrated on defective CuInSe₂ solar modules consisting of several solar cells serially interconnected and having solar efficiencies considerably below the average. By using the accurate localization of the defects by the (mu) -TDL method further investigations were performed and the origin for the defect was found. The (mu) -TDL method is also applicable to solar cells and modules consisting of other materials, such as amorphous Si or CdTe. The (mu) TDL method is suitable for the solar module development as well as for non- destructive production control.

Pulsed infrared thermographic inspection has proven to be a fast, accurate, reliable and cost effective NDE alternative to traditional ultrasonic NDE of commercial aircraft structures. Accurate damage assessment and verification of proper repair is of utmost importance to the commercial aircraft operator today. Pulsed infrared thermographic inspection can be utilized on a wide variety of aircraft structures with a high degree of accuracy. Acoustical structures that previously could not be scanned with traditional ultrasonic methods can be evaluated using pulsed infrared thermographic inspection.

The X-33 program is a team effort sponsored by NASA under Cooperative Agreement NCC8-115, and led by the Lockheed Martin Corporation. Team member BFGoodrich Aerospace Aerostructures Group (formerly Rohr) is responsible for design, manufacture, and integration of the Thermal Protection System (TPS) of the X-33 launch vehicle. The X-33 is a half-scale, experimental prototype of a vehicle called RLV (Reusable Launch Vehicle) or VentureStar^TM, an SSTO (single stage to orbit) vehicle, which is a proposed successor to the aging Space Shuttle. Thermographic testing has been employed by BFGoodrich Aerospace Aerostructures Group for a wide variety of uses in the testing of components of the X-33. Thermographic NDT (TNDT) has been used for inspecting large graphite- epoxy/aluminum honeycomb sandwich panels used on the Leeward Aeroshell structure of the X-33. And TNDT is being evaluated for use in inspecting carbon-carbon composite parts such as the nosecap and wing leading edge components. Pulsed Infrared Testing (PIRT), a special form of TNDT, is used for the routine inspection of sandwich panels made of brazed inconel honeycomb and facesheets. In the developmental and qualification testing of sub-elements of the X-33, thermography has been used to monitor (1) Arc Jet tests at NASA Ames Research Center in Mountain view, CA and NASA Johnson Space Center in Houston, TX, (2) High Temperature (wind) Tunnel Tests (HTT) at Nasa Langley Research Center in Langley, VA, and (3) Hot Gas Tests at NASA Marshall Space Flight Center in Huntsville, AL.

Solder quality of two ball grid array electronic components were studied by using a photothermal inspection technique. In order to introduce artificial defects into the components, columns of soldering joint balls were removed between the electronic component and the printed circuit board. From one of the components, the copper heat slug was also removed to enhance the possibilities for detecting the defects. The components were heated with laser light, and their surface temperatures were monitored with an infrared camera. After heating the component for 1.5 seconds, the defects were resolved, if the plastic covering was removed. In the case of the second component with intact plastic covering, the defects under the component were not resolved. The defects were not visible through the printed circuit board either.

Interdependence between the development of temperature gradients at the solid-liquid interface during solidification of metals and the formation of local defects demands for thermal investigation. In foundry practice thermocouples are used to control the die's overall cooling-rate, but fluctuations in product quality still occur. Capturing FIR- thermograms after opening the die visualizes the state, when most thermal throughput has already flattened the temperature gradients in the mold. Rapid dissipation of heat from liquid metal to the mold during solidification forces further approach of the process investigation by slowing down the heat flux or the use of transparent mold material. Aluminum gravity casting experiments under technical vacuum conditions lead to decelerated solidification by suppression of convection and image sequences containing explicit characteristics that could be assigned to local shrinkage of the casting. Hence relevant clusters are extracted and thermal profiles are drawn from image series, pointing out correlations between feeding performance from the sink heads and the appearance of local defects. Tracing thermal processes in vacuum casting can scarcely be transferred to image data in foundry practice, since only little analogies exist between atmospheric and vacuum casting. The diagnosis of the casting process requires detection of the still closed mold using a transparent silica- aerogel sheet as part of the die. Hereby thermograms of the initial heat input are recorded by adapting a NIR-camera in addition to the FIR-unit. Thus the entire thermal compensation at the joint face for each casting is visualized. This experimental set-up is used for image sequence analysis related to the intermediate casting phases of mold filling, body formation and solidification shrinkage.

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.

Tools for hot forging are exposed to complex stresses during their life-cycle. Therefore, forging dies should have a high wear resistance and toughness on the surface, combined with excellent thermal conductivity in the die body. Hot-work tool steel is appropriate for this application except from its thermal conductance. Hence, a tool consisting of hot-work tool steel in the area of contact and heat-treatable steel as die body is favorable. A smoothly graded microstructure in the joint zone between the two steel alloys is needed to match with the requirements. Fabrication of such functionally graded dies by sand casting exhibits high sensitivity to temperature and geometry dependent parameters. To melt on the inlay's surface must be ensured without destroying this region according to overheat coarsening and mixing of alloying elements. Instead of empirical methods to optimize the process parameters, a thermographic CCD-device is used for visualization of the heat flow while pouring the melt on the inlay. In fact the molten metal flow can be directed homogeneously across the bonding surface at adequate temperatures after evaluation of thermography data. The use of a silica-aerogel sheet as opaque window beneath the inlay in the mold enables systematic development of gating and risering, whereas undesirable scaling of the inlay due to the change of emissivity is retarded. Infrared image sequences clearly demonstrate the influence of different ring gating systems concerning the filling properties. Non-joined cavities may even be classified from image data. Compound cast steel tools have been manufactured and examined in forging trials validating life-cycle prolongation.

Accurate and reliable temperature measurement is necessary for the efficient production of steel and steel mill products. Many steel processing operations such as continuous casting, hot rolling and continuous annealing require the use of non- contact temperature measurement devices because the product moves and cannot be measured by contact means. This paper reviews the requirements for non-contact temperature measurement in several common steel industry processing operations and presents examples of the benefits derived from the introduction of line scanning temperature sensors to these processes.

The U.S. auto/truck industry has been mandated by the Federal government to continuously improve their fleet average gas mileage, measured in miles per gallon. Several techniques are typically used to meet these mandates, one of which is to reduce the overall mass of cars and trucks. To help accomplish this goal, lighter weight sheet metal parts, with smaller weld flanges, have been designed and fabricated. This paper will examine the cooling characteristics of various water cooled weld electrodes and shanks used in resistance spot welding applications. The smaller weld flanges utilized in modern vehicle sheet metal fabrications have increased industry's interest in using one size of weld electrode (1/2 inch diameter) for certain spot welding operations. The welding community wants more data about the cooling characteristics of these 1/2 inch weld electrodes. To hep define the cooling characteristics, an infrared radiometer thermal vision system (TVS) was used to capture images (thermograms) of the heating and cooling cycles of several size combinations of weld electrodes under typical production conditions. Tests results will show why the open ended shanks are more suitable for cooling the weld electrode assembly then closed ended shanks.

The primary production of steel in integrated mills commonly uses Pugh-type railroad cars to transport molten iron from the Blast Furnace process to the Basic Oxygen Furnace Process. Thermal imaging and analysis can be used to monitor the condition of the refractory within these railroad cars. This results in the avoidance of molten metal breakouts on the cars and the maximization of the refractory campaign life. An additional benefit is the significant savings on the maintenance costs of this equipment and greater production efficiencies through planned maintenance practices. These railroad cars are football shaped with an opening at the top and are commonly known as 'subs' or 'bottle cars' in the steel industry. The shell of the vessel serves as both the reservoir for the molten metal and as the structural frame of the car. The interior of the shell is typically lined with ceramic refractory. Periodic applications of gunnite material maintain the integrity of the refractory. Other combinations of materials are also used within the shells of these cars to provide an insulating barrier between the molten iron and the steel shell. In the past these cars were pulled from service for maintenance inspection and repair based on the tons of metal passed through the car during normal production. The refractory condition could not be assessed until the car had cooled down enough for an internal visual inspection. Thermal imaging equipment is now being used to monitor the radiated heat from the shells of these railroad cars to assess the need for maintenance. High and low temperatures are recorded in several different areas of the vessel and are compared with benchmarks developed through several years of measurements and experience. Not only is the hottest temperature of the shell important but also the difference between this and the coldest temperature on the shell. The hottest temperature gives an indication of the thickness of the refractory in a certain area. The difference between the hottest and coldest temperatures gives an indication as to the amount of thermal growth induced stress the shell is exposed to. When the shell temperatures breach the established limits, the car is pulled from service for inspection and refractory lining maintenance. The planning and efficiency of refractory lining maintenance is greatly improved through a well established thermographic monitoring program. Problems that arise earlier than anticipated are quickly noted and rectified, avoiding the cost of product loss and equipment repair or replacement. Refractories that last longer than expected may be left in service to maximize the campaign life of those linings.

The emergence of the uncooled, solid state infrared sensors has enabled engineers to build a new type of machine vision system: infrared machine vision (IRMV) increasing performance in typical machine vision applications by working in a different portion of the electromagnetic spectrum. New applications, new markets, and new image processing tools.

This paper is based on a research project carried out during 1997. The objective was to study how an infrared camera can be used for condition monitoring of converters in the steel industry and the conditions under which thermal scanning can be used to estimate wear of a converter's refractory lining. The objects of the study were the chrome converter of Outokumpu Polarit Oy and the LD-converter (BOF) of Rautaruukki Oy Raahe Steel. The condition of the refractory lining of a converter is presently monitored by periodically measuring the wear of the wall with a laser measuring device during shutdowns or between heats. A breakout of the lining is very costly due to resulting interruptions of the manufacturing process. The study was implemented by carrying out a series of tests at both production plants. Wear of the converters was measured using laser measuring equipment. The surface temperature distribution of the converters was measured simultaneously. The results of the laser measurements and thermal scanning were compared. On the basis of the results of this study, it is possible to increase and intensify the use of thermal scanning in condition monitoring of processes of the steel industry or as a process monitoring instrument. Thermal scanning has the significant advantage over other thickness measuring methods that the process need not be interrupted for measuring. The research project will continue in 1999.

This presentation provides insights of a long term 'champion' of many condition monitoring technologies and a Level III infra red thermographer. The co-authors present recommendations based on their observations of infra red and other components of predictive, condition monitoring programs in manufacturing, utility and government defense and energy activities. As predictive maintenance service providers, trainers, informal observers and formal auditors of such programs, the co-authors provide a unique perspective that can be useful to practitioners, managers and customers of advanced programs. Each has over 30 years experience in the field of machinery operation, maintenance, and support the origins of which can be traced to and through the demanding requirements of the U.S. Navy nuclear submarine forces. They have over 10 years each of experience with programs in many different countries on 3 continents. Recommendations are provided on the following: (1) Leadership and Management Support (For survival); (2) Life Cycle View (For establishment of a firm and stable foundation for a program); (3) Training and Orientation (For thermographers as well as operators, managers and others); (4) Analyst Flexibility (To innovate, explore and develop their understanding of machinery condition); (5) Reports and Program Justification (For program visibility and continued expansion); (6) Commitment to Continuous Improvement of Capability and Productivity (Through application of updated hardware and software); (7) Mutual Support by Analysts (By those inside and outside of the immediate organization); (8) Use of Multiple Technologies and System Experts to Help Define Problems (Through the use of correlation analysis of data from up to 15 technologies. An example correlation analysis table for AC and DC motors is provided.); (9) Root Cause Analysis (Allows a shift from reactive to proactive stance for a program); (10) Master Equipment Identification and Technology Application (To place the condition monitoring program in perspective); (11) Use of procedures for Predictive, Condition Monitoring and maintenance in general (To get consistent results); (12) Developing a scheme for predictive, condition monitoring personnel qualification and certification (To provide a career path and incentive to advance skill level and value to the company); (13) Analyst Assignment to Technologies and Related Duties (To make intelligent use of the skills of individuals assigned); (14) Condition Monitoring Analyst Selection Criteria (Key attributes for success are mentioned.); (15) Design and Modification to Support Monitoring (For old and new machinery to facilitate data acquisition); (16) Establishment of a Museum of Components and Samples Pulled from Service for Cause (For orientation and awareness training of operators and managers and exchange of information between analysts); (17) Goals (To promote a proactive program approach for machinery condition improvement).

The study of the operation and performance of natural gas fired sealing lines for polyethylene coated beverage containers was performed. Both thermal and geometric data was abstracted from the thermal scans and used to characterize the performance of the sealing line. The impact of process operating variables such as line speed and carton to carton spacing was studied. Recommendations for system improvements, instrumentation and process control were made.

Thermal imaging of microscopic targets has become a critical need in the manufacturing of semiconductors and other electronic devices as thermal budgets become ever more demanding and devices become more compact and powerful. This paper describes the third generation of thermal microimagers, representing the newest advances in a twenty-year evolution of instruments having the unique capability of spatial emissivity correction for 'true' surface temperature measurement. The detection and identification of design and process defects and the management of device thermal budgets are described. The achievement of a measurement spatial resolution of better than 3 micrometers, previously unattainable, is also described.

Infrared thermography (IR) is widely used by electric utilities as an integral part of their predictive maintenance program. IR is utilized for inspection of a variety of plant mechanical and electrical components. Additionally, IR can be used to provide thermal performance information for other key plant systems, including assessment of cooling towers. Cooling tower performance directly affects availability and heat rate in fossil and nuclear power plants. Optimal tower performance contributes to efficient turbine operation and maximum power output. It is estimated that up to half of the cooling towers installed have failed to meet their design performance specifications. As a result, any additional degradation of tower performance resulting from fouling, valve degradation, unbalanced flow, or a poor maintenance practice has a direct effect on generation output. We have collected infrared thermography images of mechanical draft cooling towers, as part of Evaluation of IR Technology Applied to Cooling Tower Performance. IR images have been analyzed to provide information regarding general performance conditions and identification of operational deficiencies related to thermal performance. Similarly, IR can be implemented for monitoring of tower flow balance activities and for post-maintenance surveillance. To date, IR images have been used to identify areas of general flow imbalance, flooding or limited flow in individual cells, missing or broken tower fill material, fan performance and other problems related to maintenance or operational issues. Additionally, an attempt is being made to use quantitative thermal data, provided by the IR image analysis software, in conjunction with condenser input/output site ambient information, to evaluate and compare individual tower cell performance.

Present findings of two recent case studies. One involves transformer failures on three computer-stores within eight hours of their grand opening. The second discusses the findings during an infrared thermography-training course for electric utility engineers of a transformer vault serving an industrial customer. Both of these deal with overloaded neutral conductors. Historically, the average neutral conductor carried only the imbalance of the current between the phases of a three-phase system. This current was typically small in relation to the load being served. In fact, for economic reasons many neutrals were installed smaller than their associated phase conductors. Today however, certain types of loads (non-linear loads such as computers) and certain transformer connections (4 bushing single phase with a collector bus) cause the neutral to have up to three times as much amperage as the phase conductors. This paper will discuss the conditions under which such loading occurs and further investigate steps that can be taken/recommended should an infrared test indicate an overloaded neutral conductor.

Thermographic measurements have been made from the air on a small electrical power distribution station situated in the country, near a village. The objective was to study the conditions of detection of possible failures in the electric elements of the station. For this purpose, thermal images were obtained with an infrared scanner in the 8 - 14 micrometer spectral regions from heights ranging between 300 and 1000 feet. The scanner was mounted in a Porter Pilatus aircraft. Thermographic images were obtained in gray tones or false colors. The apparent radiation contrast was evaluated at different hours in spring, summer and winter. Emitted and reflected radiation was considered under various atmospheric conditions. The emissivity coefficients of the electrical elements of the station and of the background were evaluated. Images selected are presented with results and conclusions.

Many thermographers have touted infrared thermography as an effective maintenance tool for evaluating steam traps for years. However, several investigators have raised questions about thermal measurement's effectiveness in this application. This paper explores and compares infrared thermography and ultrasonic detection methods for steam trap testing and provides guidelines for a successful trap survey.

Thermography and IR pyrometers are currently widely accepted as tools in the preventive and predictive maintenance (PPM) of electrical equipment. This paper shows practical case studies of the combined use of IR cameras and IR pyrometers in the maintenance cycle. The results show that the proper use of both types of equipment can improve the overall efficiency of the maintenance cycle measured as the ratio of the number of defects correctly repaired and the total number of defects detected during inspection. With today's modern equipment the results can be further improved provided the input and output from the two instrument types can be synchronized.

Bearing wear and the threat of downtime have plagued assembly lines for many years. Bearings on slow moving equipment, such as conveyors, are no exception to this problem. At the General Motors Fairfax Assembly Plant in Kansas City, Kansas, we are trying to find a solution to prevent these occurrences. Due to the slow moving nature of the production process, regular preventive maintenance has been the traditional method to regulate these problems. Now, with the aid of IR Thermography, we are able to find potential problems before they occur. The presentation will show visual and thermal images, before and after repairs, along with our reporting methods of any exceptions. This paper will touch on a few of our slow moving equipment finds.

The importance of infrared (IR) technology and analysis in today's world of predictive maintenance and reliability- centered maintenance cannot be understated. The use of infrared is especially important in facilities that are required to maintain a high degree of equipment reliability because of plant or public safety concerns. As with all maintenance tools, particularly those used in predictive maintenance approaches, training plays a key role in their effectiveness and the benefit gained from their use. This paper details an effort to transfer IR technology to Soviet- designed nuclear power plants in Russia, Ukraine, and Lithuania. Delivery of this technology and post-delivery training activities have been completed recently at the Chornobyl nuclear power plant in Ukraine. Many interesting challenges were encountered during this effort. Hardware procurement and delivery of IR technology to a sensitive country were complicated by United States regulations. Freight and shipping infrastructure and host-country customs policies complicated hardware transport. Training activities were complicated by special hardware, software and training material translation needs, limited communication opportunities, and site logistical concerns. These challenges and others encountered while supplying the Chornobyl plant with state-of-the-art IR technology are described in this paper.

The utilization of thermal imaging in the evaluation of the human breast has been for the past two decades a highly effective form of screening for breast cancer and other breast disease. The procedure however, is not without controversy and a continuing debate concerning the competitive paradox with mammography as the gold standard in breast cancer screening/detection still exists. This paper and its accompanying oral presentation at Thermosense XXI will provide a brief historic overview of breast thermal imaging and will explore the authors concepts of the paradigm shift which needs to occur in order for breast thermal imaging to gain acceptance in the scientific, medical, and public communities. Early thermal imaging equipment sold for medical application were based on liquid crystal detector plates, or electronic low band infrared detectors. While the final output of these devices was quite colorful and impressive, they lacked the quantification necessary to accurately measure temperature from a medical perspective, and as such, many false positive findings and papers were produced which damaged the early credibility of the procedure. The author has previously suggested appropriate changes in both technology and in utilization protocol for correction of errors which have hindered the advancement and indeed, the further development and implementation of this most beneficial quantitative diagnostic tool.

Throughout the automotive industry there has been an increasing concern and focus on the thermal comfort of occupants. Manufacturers are continuously striving to improve heating and air conditioning performance to comply with expanding customer needs. To optimize these systems, the technology to acquire data must also be enhanced. In this evaluation, the standard use of isolated thermocouple location technology is compared to utilizing infrared thermal vision in an air conditioning performance assessment. Infrared data on an actual occupant is correlated to breath and air conditioning output temperatures measured by positioned thermocouples. The use of infrared thermal vision highlights various areas of comfort and discomfort experienced by the occupant. The evaluation involves utilizing an infrared thermal vision camera to film an occupant in the vehicle as the following test procedure is run. The vehicle is soaked in full sun load until the interior temperature reaches a minimum of 150 degrees F (65.6 degrees Celsius). The occupant enters the vehicle and takes an initial temperature reading. The air conditioning is turned on to full cold, full fan speed, and recirculation mode. While being filmed, the driver drives for sixty minutes at 30 miles per hour (48.3 kph). The thermocouples acquire data in one minute intervals while the infrared camera films the cooling process of the occupant.

Recent advances in infrared thermal imaging technology have brought about a number of new thermal techniques that provide quantitative and qualitative information in the area of vehicle safety. The purpose of this paper is to provide background and fundamental information of vehicle fire propagation and surface temperature as seen from an infrared thermal imaging system. The development of high-resolution, fast-image processing has aided in the attractiveness of thermography as a Research and Development tool.

While human eyes are amazingly adaptable, they are not ideally designed for the task of driving at night. Among the most serious problems drivers face at night are not being able to see objects that are beyond the range of their headlamps and being blinded by headlamps of oncoming traffic. While only about one-quarter of vehicle miles are driven at night, over half of vehicle related fatalities occur at night. Having the goal of improving nighttime driving safety, Cadillac along with Raytheon Systems Company and Delphi-Delco Electronics have developed a night vision system consisting of a passive infrared sensor, a head-up display, and display controls. The night vision system will be offered as a production option on the 2000 Cadillac De Ville. This paper will describe the development of Cadillac's Night Vision.

With the use of synthetic fabrics and threads in high speed sewing, needle heating due to friction between the needle and the fabric becomes a serious problem which limits further increase of the sewing speed. The high temperature in the needle can accelerate thread wear, cause wear at the needle eye, and damage the thread. It can also scorch the fabric, as well as temper and weaken the needle itself. Experimental methods, such as: infrared radiometry, infrared pyrometry, etc., have been applied to analyze this problem in previous studies. They revealed some important factors that affect the needle peak steady state temperature. In this study the numerical (FEA) model developed to simulate the needle heating is fine tuned and verified via infrared radiometry. The FEA model incorporates detailed needle geometry and the effects of thread on needle heating. It deals with a transient heat transfer process with time and position dependent boundary conditions. It correlates various important factors that affect the needle heating, such as needle characteristics, fabric properties, and sewing conditions to the needle temperature distribution. Given various needle geometries, sewing conditions, and fabric properties, the model can simulate the needle heating process, including the initial heating phase and the steady state. It can also predict the temperature distribution in the needle as well as the time to reach steady state. The trends of the simulation results correlate well with experiments.

The decision to use Thermographic Nondestructive Testing (TNDT) for a particular application is frequently made on an empirical basis using flat bottom hole test samples. In many cases, results are interpreted using subjective, non- quantitative criteria that cannot be generalized to apply to a broader range of applications. Although sensitivity is generally considered an important indicator of TNDT system performance, subsurface spatial resolution is rarely discussed. We present a methodology for TNDT system performance characterization that is loosely modeled on the Modulation Transfer Function (MTF) used in visual imaging. Once a TNDT system has been characterized using this approach, system performance for other applications can be accurately predicted. Examples including a steel resolution target and flat bottom holes in a CMC panel are discussed.

Extraction of temperatures or temperature differences with thermography is not possible without knowledge of the target emissivity. As the technology of thermography evolves, many applications from predictive maintenance through R&D projects have increasingly stringent requirements for quality temperature measurement. Today's IR cameras and software can correct for target emissivity variations on a point-by-point basis or over the entire image. One problem is how to measure emissivity, and how emissivity measurement uncertainties propagate to temperature uncertainties. This paper discusses emissivity measurement techniques, why table values are often not valid for a particular IR camera (why you must measure emissivity) and how emissivity measurement accuracy affects temperature measurement accuracy (error budget for opaque targets).

The use of a Peltier device in thermal contact with a specimen can provide heat source and sink. The utilization of this equipment is experimented, applying successive heating and cooling stages on various specimens and measuring the temperature outside of the contact area. Oscillating temperature in time and space can provide indication on the thermal diffusivity. The appealing ability of sourcing and sinking heat, with average null effect on temperature, may represent an innovative approach with respect to traditional simulation technique. A simple analytical model is exploited for recovering the inversion equations. Numerical simulation allows to better understand the real proces on the sample.

The presented system is based upon a differential imaging radiometry technique, differential in both spectral and spatial domains: (1) The observation of a scene, acting as an infrared complex source is realized through a set of wide band filters: (A) a 'reference' filter, the transmission of which is located outside the absorption (or emission) features of the gas of interest: the resulting picture characterizes the scene background. (B) a 'measure' filter, the transmission of which incudes the absorption or emission bands of the gas of interest while remaining as close as possible to the 'reference' filter. The use of such filters, characterized by a high IR transmission over a wide wavelength band unlike the conventional radiometric methods, preserves the imaging function of the infrared camera. (2) A specific treatment is applied to the resulting pictures. Its originality consists in that gas concentration is not directly computed from the received IR flux, but from the image contrast variations between the two filtered images. In this way, the emission flux of gas cloud can be eliminated. Finally, the comparison of the 'contrast' images gives an absolute and quantitative measurement of gas concentration of the cloud integrated along the line of sight, whatever the respective temperatures of the gas cloud and the background scene are. A first generation demonstrator based on 8 - 12 micrometer commercial radiometric camera, and integrating a quasi-real time processing software, was tested on several gas, both in closed chamber and in open field. This paper presents an overview of the measurement technique and natural gas cloud measurement in atmosphere.

Low emissivity with corresponding low thermal emission is a problem which has long afflicted infrared thermography. The problem is aggravated by reflected thermal energy which increases as the emissivity decreases, thus reducing the net signal-to-noise ratio, which degrades the resulting temperature reconstructions. Additional errors are introduced from the traditional emissivity-correction approaches, wherein one attempts to correct for emissivity either using thermocouples or using one or more baseline images, collected at known temperatures. These corrections are numerically equivalent to image differencing. Errors in the baseline images are therefore additive, causing the resulting measurement error to either double or triple. The practical application of thermal imagery usually entails coating the objective surface to increase the emissivity to a uniform and repeatable value. While the author recommends that the thermographer still adhere to this practice, he has devised a minimal entropy reconstructions which not only correct for emissivity variations, but also corrects for variations in sensor response, using the baseline images at known temperatures to correct for these values. The minimal energy reconstruction is actually based on a modified Hopfield neural network which finds the resulting image which best explains the observed data and baseline data, having minimal entropy change between adjacent pixels. The autocorrelation of temperatures between adjacent pixels is a feature of most close-up thermal images. A surprising result from transient heating data indicates that the resulting corrected thermal images have less measurement error and are closer to the situational truth than the original data.

Many thermal processes pass very quickly. The normal frame rate of radiometric scanners or FPA cameras is sometimes far below what might be needed in order to see what is happening with the object. When it comes to measurement there is nothing yet to match the measurement accuracy of the best scanning devices. When very high measurement accuracy has to be combined with highest possible data acquisition rate, the best way today is to use the scanning technique, with the scanner set for line scanning. Thus it is possible to acquire thermal information also from very fast processes. Computer processing of thermal information is today applied in almost 100% of the cases. If this is applied to thermal information, which is acquired by Fast line scanning, the results can be very interesting. This method has been successfully applied e.g. to tires, disk brakes, fusion research, and to analysis of explosions in connections with the development of air-bags. The paper describes the above mentioned applications. This includes a method description and some thermograms, which show the final result.

On base of the solid state physics and theory of nonlinear oscillations interpretations a development of the thermofluctuation fatigue of mechanics theory is formulated. It is shown that electrical damage has resonance nature. An influence of the electron processes on the first time pre- breakdown stage with mainly microdefects formation is considered. The proposed theory contains consideration of polarization of the local domains the 'cross-pieces' between neighboring micropores, which formed elementary electrical dipoles. Strong external constant electrical field leads to negative differential resistance of the local dielectric domains with N- or S-type current-voltage-characteristic (CVC) parts and as a result to current oscillations and electromagnetic wave radiation from MDM structure (as in Gunn's diode). On base of A. Puankare's limit cycles nonlinear oscillations theory it is shown that defects formation leads to self-exciting current oscillations and microwave radiation. This information can be used in thermosense NDT and, that is principal, for elimination of the defects, which arose under fabrication of electronic devices.

In order to reduce a serious problem connected with the buried mines, various detection technologies are used. The main disadvantage of applying the IRT method is presence of plenty false indications in thermograms. A simple use of IRT equipment with better temperature resolution would not help in distinguishing the mines, since noise comes not from a camera, but from soil surface. Recognizing the role of time and space variability of moisture and density of sand and possibilities to express it quantitatively plays an important role. In our model of thermal properties of the soil the volumetric unit of the soil consists of mineral and organic particles, as well as water and air. All needed parameters can be calculated. Calculations of thermal signatures of the underground objects were made basing on 2D-heat equation for the sinus type heating of the three-layer model of cylindrical geometry and cooling by convection. Measurements were made for field and laboratory stand-ups, using methodologies typical for 'single- shot' measurements as well as analyses of transient processes based on sequence of thermograms. Results of simulations and measurements confirm expectation that high level of 'radiant noises' is caused mainly by differences in the moisture and sand density levels.

Exterior wall assemblies that enclose medium to large buildings can be classified into four generic wall types: (1) masonry, (2) architectural precast, (3) metal and glass curtain wall, (4) insulated steel assemblies. Within these generic types of assemblies there are variations within the cladding type as well as assembly configuration. Investigations of exterior wall assemblies using infrared thermographic radiometers are carried out to obtain information related to: (1) moisture accumulation, (2) air leakage, (3) variations within thermal resistances of similar assembly configuration, and (4) structural thermal bridging. Each generic type of wall assembly is designed to perform in a different way and their use in various conditions are governed by their performance specification. The thermal patterns generated by each of these wall types is unique. The tolerances for error on each type of assembly varies. Therefore the inspection methodology for each type of wall assembly needs to be defined to isolate the specific performance parameters relevant to each wall assembly type. This paper identifies the various exterior wall assembly types, discusses the relevant performance parameters that make these assemblies perform properly and defines the inspection requirements necessary for accurate assessment of the deficiencies within the exterior wall enclosures of buildings.

In the state of Florida, explosive population increases have promoted monumental efforts by the building industry to keep up with the demand for public facilities such as schools, hospitals and multiple story housing (condominiums). The onslaught has brought with it various industry-related problems, one of which is interior building permeation more commonly known as moisture intrusion. External Insulation and Finish Systems (EIFS) and stucco veneer buildings are cost efficient and follow the guidelines for ever shortening construction timeframes; which is part of the reason for failures found through thermographic analysis. This combined with the underlying structural building components and their differential thermal expansion known as the Coefficient of Expansion loan themselves to the problematic conditions observed in numerous projects throughout the southeast. Hurricanes, severe thunderstorms, heavy humidity and other forms of atmospheric conditions found in the southeast (and more so in Florida), accelerate the aging process of the two aforementioned systems. These, combined with the factors described above have brought the investigation of the two systems to the forefront of countless building owners. This paper presents thermographic examples of case studies performed within the state of Florida and is presented raise concerned awareness over the extent of damage that can occur when EIFS and stucco systems fail.

A method is proposed for the moisture analysis of buildings, based on the combination of complementing monitoring techniques. A periodic IR scanning of the whole surface is combined with a visual recording, plus an automatic data logging of the environmental conditions. Thermography allows imaging the temperature pattern, while a long history of thermal hygrometric parameters come available for the fixed measurements at selected points. The used equipment is relatively simple and competitive. A very few thermographic surveys are integrated by several periodic scanning, using an IR pyrometer. The visual monitoring is of great help in rendering results and documenting surface appearance at different seasons. About 20 probes are sufficient to measure thermal hygrometric parameters and evaluate the condensation risk. A review of algorithms for the moisture testing by thermography and guidelines for the identification of the moisture sources in thick historical buildings is presented. A numerical model has been adopted to simulate the internal thermo-hygrometrical conditions. In such a way, data acquired could be significantly extended and gaps occurred during the data logging has been filled. As case study was identified a North-East Italian ancient church (Duomo of Venzone) destroyed by an earthquake in 1976 and fully restored under the patrol of the cultural heritage authority. A one year round monitoring of the church and tour, according to the proposed procedure, allowed to control the moisture levels both in time and space. This endorsed to identify the sources of the water flux and therefore to suggest the repairing guidelines. Experimental results are reported.

Determining the placement of reinforcing grout in single-width CMU (Concrete Masonry Unit) walls has, in the past, been a painstaking and destructive undertaking. Usually, a test is performed because -- by accident -- missing cells are discovered when a wall penetration is retrofitted or change order is executed, requiring that the wall be opened. Often, a hammer or hammer drill is used to punch holes where the grouting is supposed to be. The test results are used to extrapolate the extent of the problem. This method falls short, since the sample is so small, that only outright fraud can be found, and excess grouting cannot be determined. This paper discusses the results of a joint effort between Stockton Infrared Thermographic Services, Inc. (SITS) and Allen Applied Infrared Technology, Inc. (AAIT) to produce a methodology for using non-destructive infrared thermography to ensure that the design specifications are being met.

The classification of fire resistance occurs with the aid of the results of fire tests. The criteria for the classification are determined in international standards. The use of infrared thermography not only for qualitative observation but also for quantitative measurement during fire tests of glazing and glazed elements makes it possible to check the demands of national or international standards as ISO 3009 and forthcoming EN 1364 more exactly.

Infrared thermal imagers are used at Lawrence Berkeley National Laboratory to study heat transfer through components of building thermal envelopes. Two thermal chambers maintain steady-state heat flow through test specimens under environmental conditions for winter heating design. Infrared thermography is used to map surface temperatures on the specimens' warm side. Features of the quantitative thermography process include use of external reference emitters, complex background corrections, and spatial location markers. Typical uncertainties in the data are plus or minus 0.5 degrees Celsius and 3 mm. Temperature controlled and directly measured external reference emitters are used to correct data from each thermal image. Complex background corrections use arrays of values for background thermal radiation in calculating temperatures of self-viewing surfaces. Temperature results are used to validate computer programs that predict heat flow including Finite-Element Analysis (FEA) conduction simulations and conjugate Computational Fluid Dynamics (CFD) simulations. Results are also used to study natural convection surface heat transfer. Example data show the distribution of temperatures down the center lines of an insulated window.

Most present day low and medium rise buildings constructed in Canada use some form of cavity wall design for their exterior walls. These types of wall assemblies use a broad range of cladding materials such as brick, stone, wood, sheet metal, porcelain enamel or metal panels, cementitious materials and plastics. The interior assemblies of these walls include the air barrier, vapor barrier and insulation layers. The cladding is separated from the interior wall assembly by an air space of varying thickness. Dependent upon the temperature differential between the interior and exterior, the temperature between the outer surface of the interior wall assembly and the inner surface of the exterior cladding under conditions in which air movement is restricted will give rise to convective heat loss mechanisms. This paper will look at how these convective heat loss patterns manifest themselves as thermal patterns on exterior surfaces of cladding materials. Similar details will be illustrated under various pressure differential conditions through the entire building envelope assembly. Various types of exterior wall assemblies will be discussed.

Abstract not available.

A new nondestructive testing method is proposed for the detection of cracks in concrete structures. This method is based on temperature measurement using infrared thermography under microwave heating. Cracks to be detected in concrete structures are usually surface-breaking, and water can penetrate into cracks. When microwave is applied to the concrete structure with wet cracks, water in the cracks can be selectively heated by microwave. In this case temperature distribution around the crack is expected to show the similar distribution as that of the linear heat sources. Thus cracks can be detected from the thermal images measured immediately after the microwave application. Preliminary experimental investigation was carried out for a mortar-block specimen with artificial cracks using a microwave oven. It was found that cracks can be detected from the thermal images, in which wet cracks were selectively heated by microwave.

The infrared detection method has been carried out to detect the invisible flaw existing in a medium by observing a transient phase difference of a radiation temperature difference of deterioration parts and invisible flaws using the infrared radiometer. In order to evaluate the detection limit of the flaw using the infrared radiometer, it is important to confirm resolution characteristics of the radiometer like noise equivalent temperature difference NETD, minimum detectable temperature difference MDTD and minimum resolvable temperature difference MRTD under jurisdiction of ASTM, JIS and so on. However, the detection limit of the flaw displayed in the CRT of the radiometer is determined by the function of those values and surface radiation characteristics like emissivity, reflectivity and their spatial variance of the material and flaws used. The paper represents experimental and numerical results on the relation between the detection limit of the flaw and resolution characteristics of the radiometer itself.

Thermal engineering of electronics products has become more essential, mainly because of increasing power densities due to the past rate of miniaturization at all assembly levels. One tool, which facilitates this challenging work, is infrared (IR) thermography. With an IR camera, it is often quite easy to quickly inspect an electronic device, or usually printed circuit board (PCB), by detecting and locating possible hot spots. However, due to the relative ease of use of modern IR cameras equipped with diverse special functions, it is also rather easy to make serious misinterpretations. Typical pitfalls that arise in electronics applications include considerable emissivity variations, for instance on common PCB's and the sometimes-drastic changes of operation conditions when the device under test is removed from its operational environment to allow imaging. In this paper, these pitfalls, their effects, and the feasibility of possible remedies are discussed.

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.

A new thermographic NDT technique was proposed, in which singularity of the temperature field near crack tips under application of the periodically modulated electric current was measured using differential thermography based on lock-in data processing technique. Experimental investigation was made on the resolution and the applicability in the detection of through-thickness cracks embedded in steel plate samples. Modulated electric current was applied to the cracked sample by an induction coil. Differential thermal images synchronized to the reference current modulation signal were taken by the differential thermography. Significant singular temperature field was observed at the crack tips in the differential thermal images. The cracks were found to be sensitively detected by the proposed technique in good resolution compared with the singular method using a conventional thermographic temperature measurement.

High Temperature X-ray Diffraction (HTXRD) is a very powerful tool for studies of reaction kinetics, phase transformations, and lattice thermal expansion of advanced materials. Accurate temperature measurement is a critical part of the technique. Traditionally, thermocouples, thermisters, and optical pyrometers have been used for temperature control and measurement, and temperature could only be measured at a single point. Infrared imaging was utilized in this study to characterize the thermal gradients resulting from various sample and furnace configurations in a commercial strip heater furnace. Furnace configurations include a metallic strip heater, with and without a secondary surround heater, or surround heater alone. Sample configurations include low and high thermal conductivity powders and solids. The IR imaging results have been used to calibrate sample temperatures in the HTXRD furnace.

For years predictive maintenance thermographers have been challenged by industrial targets to determine whether they had a problem, and if they did how big was it. We have struggled with low emissivity and unknown emissivity targets. We have observed thermal patterns and temperatures and asked whether the target was operating normally or if the heat patterns indicated a problem condition. Through years of experience, we have built a body of knowledge. Conferences such as Thermosense are where we share that knowledge with others. From this, we realize that much more could be done if our targets were thermographer-friendly. Now it is time to ask the equipment manufacturers to step up to the plate and acknowledge the viability of thermography as a predictive maintenance and non-destructive test tool. They build the targets we look at. They can help us in a least three areas: (1) We need to work with them to specify a baseline thermal signature for their equipment operating under normal conditions. Thermograms would be included with the operating manual or equipment test results. Thermography would be part of acceptance and installation testing. (2) We need to ask them to include high emissivity coatings in their designs for certain targets. (3) We need to work with them to develop thermal models that will indicate thermal signatures under all types of environmental conditions for both normal and abnormal operation. Thermal modeling programs developed by the defense community that will display a surface thermal image are available for PCs. With the help of target equipment manufacturers, we can significantly advance the state-of-the- art of thermography applications. We can be even more confident of our recommendations. We can evaluate targets that couldn't be evaluated before, expanding our applications. We can have backup on criticality calls with manufacturers' data. In short, we can do our job better.