Academic literature on the topic 'Ceramic Infrared (IR) Heater'

The purpose of this study was to develop the warm-up suit that is comfortable as well as has good thermal performance. The function of warm-up suit is to keep the body warm and thus to lose it’s weight by sweating. Ceramic powders, such as zirconium and magnesium oxide have been incorporated into the textile structures to utilize the far infrared radiation effect of ceramics, which heat substrates homogeneously by activating molecular motion. Thermal manikin tests were conducted to determine the clothing insulation and evaporative resistance of the selected warm-up suits. Also, the far IR emission effects of ceramics containing laminate on the body heat transfer were evaluated with the thermogram data using IR camera. The results showed that the ceramics inside laminate slightly increased the thermal insulation and the evaporative resistance. Thermogram showed that when the fabric was heated with the thermal manikin, surface mean temperatures of fabrics were increased as the ceramic incorporated, and the heat storage performance was confirmed.

The heat resistance of fabric enhanced by bio-ceramic additives (BCAs) is investigated theoretically and experimentally in order to determine the influence of modification of the infrared (IR) absorption property of the fabric. The enhanced IR sensitivity of textiles improves the thermoregulatory processes when worn in cold environments. The finite element model has been developed by taking into account the coupled phenomena of heat conduction, surface convection and the interaction of the fabric with IR power flux by employing heat transfer differential equations and the Stefan–Boltzmann law. Evaluations of IR absorptivity, reflectivity and transmissivity, the temperature transients during the hot plate chamber test and heat retaining properties of the fabric heated by an IR lamp have been obtained experimentally and simulated by means of the developed finite element model. The values of model parameters have been found, which provided a satisfactory match between the computation and the experiment in all considered cases. Simultaneously, the obtained values were reasonably close to rough theoretical estimations. Efforts have been made to distinguish from each other the influence of diffusive and radiative components of heat transfer, which affect the results of thermal resistance tests. The comparative analysis of contributions of different heat exchange mechanisms allows a better understanding of the peculiarities of standard heat resistance measurement procedures applied to BCA-enhanced fabrics and facilitates the validation of the computational models.

This study has shown the possibility of achieving two primary considerations for the advanced fabrication of spodumene with a composition of Li2O · Al2O3 · 4SiO2 · nTiO2 (LAST) glass-ceramics by a sol-gel process, namely, an enormous reduction of sintering temperature from 1600 to 1200 °C together with the appearance of simple phases of β-spodumene/rutile as opposed to products via the conventional melting-crystallization process. Fine glass-ceramic powders with a composition of Li2O · Al2O3 · 4SiO2 (LAS) have been synthesized by the sol-gel process using Si(OC2H5)4, Al(OC2H5)3, LiOCH3, and Ti(OC2H5)4 as the starting materials. The process included well-controlled hydrolysis polycondensation of the raw alkoxides. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron diffraction (ED) analysis were utilized to study the effect of TiO2 addition on the preparation of β-spodumene powders by the sol-gel process. The gelation time of the LAST solution increases as the TiO2 content increases. For the low (<3) or high (>11) pH value, the gelation time was shortened. At pH = 5, regardless of the TiO2 content, the gel has the longest time of gelation. When the dried gels of the LAST system are heated from 800 to 1200 °C, the crystallized samples are composed of the major phase of β-spodumene and a minor phase of rutile (TiO2).

Abstract Recent developments in the use of more stable feldspar signals in the luminescence dating of sediments offer the possibility of obtaining accurate feldspar luminescence ages for ceramic artefacts; this is especially interesting in locations which do not provide suitable quartz extracts. Here we examine the application of the stable infrared stimulated luminescence signal measured at elevated temperature (in this case 290°C; pIRIR290) after stimulation at about room temperature to Levantine pottery samples. A total of 52 potsherds were collected from three superimposed iron-age units at Pella (Jordan); based on 14C dating, typology and seriation these units were deposited between 700 and 900 BCE. Sand-sized quartz extracts were unsuitable, and there was insufficient sand-sized feldspar, and so polymineral fine grains were chosen for dating. Various tests for reliability were undertaken (dose recovery, dependence of De on first stimulation temperature etc.). The pIRIR signals are weak, and 14 potsherds were rejected on this basis. Of the remainder, 3 were confidently identified as outliers. Based on those sherds for which IR signals were sufficiently intense, we use the ratio of the IR50 to pIRIR290 signals to argue that these outliers do not arise from incomplete resetting during manufacture. The ages from each layer are considerably over dispersed (typically by ∼25%) but average ages for each unit are consistent with each other and with the expected age range. The average OSL age for the site is 2840 ± 220 years (n = 35), with the overall uncertainty dominated by systematic uncertainties; this average is consistent with the range of 14C ages from 970–1270 BCE reported from across the destruction horizon. We conclude that the pIRIR290 signal is delivering accurate ages, but that the variability in age from shard to shard is much greater than would be expected from known sources of uncertainty. This demonstrates the need for site ages to be based on multiple samples; individual shard ages are unlikely to be sufficiently accurate.

Abstract. It is demonstrated how a commercially available MEMS thermopile infrared radiation sensor can be used as thermal conductivity gas detector (TCD). Since a TCD requires a heater while IR-thermopile sensors have no integrated heater, the thermopile itself is used as heater and temperature sensor at the same time. It is exposed to the measured gas environment in its housing. It is shown that, by using a simple driving circuitry, a mass-produced low-cost IR sensor can be used for hydrogen detection in applications such as hydrogen safety and smart gas metering. The sensor was tested to measure hydrogen in nitrogen with concentration of 0–100 % with a noise equivalent concentration of 3.7 ppm.

Introduction: The accumulation of fatigue and stress creates problems, including reductions in quality of life and productivity. Objectives: To investigate the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states. Methods: This study was performed as a crossover trial. Participants comprised 20 women. On different days, each participant underwent 15 min of foot warming with the far-infrared heater (far-infrared group) or remained seated for 15 min (control group). Autonomic nervous activity (low-frequency component/high-frequency component, high-frequency) and mood states scales (Profile of Mood States Second Edition and Two-Dimensional Mood Scale for Self-monitoring and Self-regulation of Momentary Mood States) during the study intervention were measured and compared between groups. Results: Low-frequency/high-frequency was significantly higher in the control group 10 min after the start of intervention than at baseline ( P = .033). Low-frequency/high-frequency was significantly lower in the far-infrared group than in the control group at 5 min ( P = .027), 10 min ( P = .011), and 15 min ( P = .015). High-frequency was significantly higher in the far-infrared group at 5 min ( P = .008), 10 min ( P = .004), and 15 min ( P = .015) than at baseline. High-frequency 5 min after the start of intervention was significantly higher in the far-infrared group than in the control group ( P = .033). POMS2 scores improved significantly more in the far-infrared group than in the control group, including in fatigue-inertia ( P = .019), tension-anxiety ( P = .025), and total mood disturbance ( P = .019). Finally, the far-infrared group showed greater improvements in Two-Dimensional Mood Scale-Short Term scores such as stability ( P = .002) and pleasure ( P = .013). Conclusion: Using the far-infrared heater to heat the feet with ceramic balls stabilized and improved mood, reduced Fatigue-Inertia and Tension-Anxiety, and alleviated total mood disturbance. Parasympathetic nervous system activation was observed from 5 min after the start of heating, suggesting that short-duration heat stimulation of the feet is effective.

Ceramic materials find use in many fields including the life sciences and environmental engineering. For example, ceramic membranes have shown to be promising filters for water treatment and virus retention. The analysis of such materials, however, remains challenging. In the present study, the potential of three vibrational spectroscopic methods for characterizing functionalized ceramic membranes for water treatment is evaluated. For this purpose, Raman scattering, infrared (IR) absorption, and solvent infrared spectroscopy (SIRS) were employed. The data were analyzed with respect to spectral changes as well as using principal component analysis (PCA). The Raman spectra allow an unambiguous discrimination of the sample types. The IR spectra do not change systematically with functionalization state of the material. Solvent infrared spectroscopy allows a systematic distinction and enables studying the molecular interactions between the membrane surface and the solvent.

Infrared imaging sensors are frequently used in thermal signature detection applications in industrial, automotive, military and many other areas. However, advanced infrared detectors are generally associated with high costs and complexity. Infrared detectors usually necessitate a thermoelectric heater–cooler for temperature stabilization and various computationally complex preprocessing algorithms for fixed pattern noise (FPN) correction. In this paper, we leverage the benefits of uncooled focal plane arrays and describe a complete digital circuit design for Field Programmable Gate Array (FPGA)-based infrared image acquisition and pre-processing. The proposed design comprises temperature compensation, non-uniformity correction, defective pixel correction cores, spatial image transformation and registration with RGB images. When implemented on Xilinx Ultrascale+ FPGA, the system achieves a throughput of 30 frames per second using the Fraunhofer IMS Digital 17 μm QVGA-IRFPA with a microbolometer array size of 320 × 240 pixels and an RGB camera with a 1024 × 720 resolution. The maximum ratio of the standard deviation to the mean of 0.35% was achieved after FPN correction.

Tensile fracture behavior of ceramic matrix composites (CMCs) was investigated using characterization tools. First, a high-speed infrared camera was used to monitor the surface temperature of the CMC specimen during mechanical testing. An infrared camera is a tool used to detect infrared (IR) radiation emitted from a specimen as a function of temperature, and it was used to analyze the temperature monitoring of specimen surface and fracture behavior during the tensile test. After the test, the microstructural analysis using SEM was performed. SEM analysis was performed to investigate the fracture mode and fracture mechanism of CMC materials. In this paper, it was found that the results of the surface temperature monitoring obtained from IR thermal imaging technology and the failure mode analysis obtained through SEM were in a good agreement. These techniques were useful tools to explain the mechanical behavior of ceramic matrix composites. The detailed experiments and testing results will be provided.

Evaporation is one of the inherent processes of our planet earth as an ecosystem. Water bodies, earth’s surface and vegetation all contribute significantly towards the total evaporation which eventually leads to the formation of clouds. The physical processes governing the evaporation from these surfaces differ significantly and thus needs to be studied individually. The factors which affect the total evaporation (evaporation & transpiration) are the surface temperature, ambient temperature, relative humidity, external wind speed, pressure, surface area and geometry. The present investigation deals with evaporation from three different surfaces: open water bodies, soil-like surfaces, and leaf-like surfaces. A ceramic infrared heater (2kW, 230V) has been used as the heater, in order to mimic the natural process, in all the experiments which were conducted in quiescent atmosphere i.e. without any external wind. The present work has been broadly categorized into two parts: - (a) evaporation from bare water surface, and (b) evaporation from a porous media. In part (a), we present experimental results on the evaporation from a bare water surface heated either from above using the infrared radiations or from below using heater immersed in the water. Heating from below leads to unstable stratification while infrared heating from above leads to stable stratification. The effect of water-side convection on the evaporation from a bare water surface has been investigated and all the experimental results have been combined to obtain a power law relation between Sherwood number (Sh) and Rayleigh number (Ra). Part (b) of the thesis has been further split into three major categories: - (1) evaporation from spheres based conventional porous media; (2) evaporation from novel porous media; and (3) evaporation from leaf-like surfaces. Mono-disperse spheres-based (non-hygroscopic) conventional porous media are used to mimic the natural soils. Glass beads (0.10-0.16 mm to 2.5-3.0 mm diameter), Stainless steel balls (1 mm diameter), sieved natural sand (0.3-0.5 mm diameter) and hydrophobic Ball Grid Array balls (0.30; 0.50; 0.76 mm diameter) have been used to create the conventional porous media. The range of Bond number (Bo) spanned in the present investigation is 2.2 ∗ 10−4 − 1.2 ∗ 10−1 based on the spheres dimensions. The experiments were conducted either in a cylindrical vessel (63 mm diameter and 90 mm height) or in rectangular acrylic boxes having dimensions similar to that of the cylindrical vessel. The heat flux received by the top surface of the porous media in majority of the experiments was 1000W/m2 which is close to the average annual solar insolation on the earths’ surface. The evaporation from these soil-type surfaces was found to undergo different and distinct stages. In the 1st stage of evaporation, commonly known as the constant rate period (CRP) regime, where the water in a confined 3D porous media remains on the surface and a high evaporation rate is observed. Surface tension-driven formations of capillary film(s) which rise to the surface are seen during CRP. The strength of the capillary has been defined in terms of a characteristic length called the capillary break-up length. In the 2nd stage of evaporation often called a falling rate period (FRP) regime, the capillary film which was supplying water to the top surface of the porous media breaks-up. The break-up, also termed as the transition regime, leads to receding liquid-vapour menisci and heat is conducted through the top dried layer to the water below where evaporation takes place the evaporation rate drops. Along with the wetting properties, the spheres size has been found to effect capillary break-up length and hence the duration of the stages of evaporation drastically. Surface images captured using a thermal camera clearly showed the presence of water till the capillary break-up length. The capillary break-up length was also found to be affected significantly by the heat flux or in other sense we can say that the evaporation rate in CRP regime is critical in deciding its duration in a spheres-based conventional porous media. In the present investigation heat flux ranged from 250-2000W/m2. Visualization has been carried out using a solution of de-ionized water and fluorescein dye. The colour contrast property (orange if dry and green in the solution form) of the fluorescein particles has been used to observe the evaporation sites in the porous media and to differentiate between the 1st and 2nd stage of evaporation. Apart from the experimental findings of single stack of mono-disperse spheres, multiple layering have also been investigated. The presence of complicated network of textural layering in the earth’s surface is a well-known fact. Along with the preferential evaporation, evaporation enhancement & suppression are reported in the experiments with texturally layered porous media independent of the orientation viz. vertical or horizontal layering. The stacking positions are also found to be critical in determining the overall evaporation characteristics. The geometry of a pore between three spheres in mutual contact is complicated. A simpler geometry for a pore could be that between two rods/plates in contact or three rods in mutual contact or stacks of either of these two. We call these types of porous media as “Novel porous media” as they possess many unique features not seen in a conventional porous media consisting of spheres. For this class of experiments the materials used to create the novel porous media were: Glass rods (2 & 3 mm diameter and 75 mm length), Glass capillaries (1.1/1.5 mm and 75 mm length), Faber-Castell pencil leads (0.7 mm diameter and 75 mm length), Glass plates (cross sectional dimension of 42 mm x 102 mm and thickness of 1.85 mm) and Cover slips (cross sectional dimension of 22 mm x 60 mm and thickness of 0.130.16 mm). The evaporation characteristics of vertically stacked rod-based novel porous media was found to be dominated by the corner films present in the near-zero radii contacts. Unlike the conventional porous media, the capillary break-up in the vertically stacked rod-based novel porous media was found to be limited by the vertical extent of the rods and not on the rod diameter. Due to the same reason, capillary break-up of vertically stacked rod-based novel porous media was also found to be independent of the heat flux range investigated in the present work. The 2nd stage of evaporation in these types of novel porous media therefore does not hold the true meaning as it is not forced by the porous media. The effect of orientation has also been investigated and the surface roughness was found to affect the evaporation dynamics drastically in horizontally stacked rod-based novel porous media. However, it is the surface roughness which was found to be dominant in case of vertically stacked plate-based novel porous media. The average size of a stoma, tiny holes present on the leaves, is nearly 20μm and the population density in majority of the plants is close to 5% of the leaf area. However the higher transpiration rates (60-70 % compared to a bare water source) sustained by a plant has remained a mystery for the phytologists. To study this we mimic the leaf-type surfaces by manufacturing silicon wafers having through holes. The leaf-mimics had different hole-diameter but same open area. The leaf-mimic with the smallest hole-size was found to evaporate the most while with increasing the hole-size the evaporation was found to decrease. In all the types of the leaf-mimic the evaporation ratio (ratio of the evaporation rate from the leaf mimic to that of the evaporation rate of a bare water surface at the same surface temperature) was found to increase with decreasing heat fluxes. The 3D nature of diffusion near these tiny holes enhances the evaporative flux, owing to increase in the concentration gradient of water vapour, which explains the high evaporation rates observed in the present work.

This study describes the development and characterization of novel high-temperature thermal storage media, based on inclusion of transition metal chlorides in the potassium-sodium chloride eutectic system, (K-Na)Cl (melting temperature of 657°C, latent heat of 278 J/g). At the melting temperature of (K-Na)Cl, infrared (IR) radiation can play a major role in the overall heat transfer process — 90 percent of spectral blackbody radiation falls in the range of 2 to 13 μm. The authors propose inclusion of small amounts (less than 0.2 wt %) of IR-active transition metal chlorides to increase radiative absorption and thereby enhance heat transfer rates. A new IR reflectance apparatus was developed to allow for determination of the spectral absorption coefficient of the newly formulated PCMs in the molten state. The apparatus consisted of an alumina crucible coated at the bottom with a reflective (platinum) or absorptive (graphite) surface, a heated ceramic crucible-holder, and a combination of zinc sulfide (ZnS) and zinc selenide (ZnSe) windows for containment of the salt and allowance of inert purge gas flow. Using this apparatus, IR spectra were obtained for various transition metal chloride additives in (K-Na)Cl, and improved infrared activity and radiative transfer properties were quantified. Further, thermophysical properties relevant to thermal energy storage (i.e., melting temperature, latent heat) are measured for the pure and additive-enhanced thermal storage medium.

In gas turbine, the enhancement of durability and the increase of reliability represent essential requirements. These issues become even more critical for components subjected to high thermal loads, as the combustion chamber, and go in parallel with the desire for higher efficiency, which resulted in a reduced amount of air that the cooling systems designers have available for the combustor liner. This work presents the results of an experimental campaign aimed to evaluate the performance on a portion of the combustion chamber liner of the latest Ansaldo Energia AE64.3A+ gas turbine. In this configuration ceramic tiles replace the previous metallic heat shields, reducing coolant consumption up to 40%. The designed test article is made up of two ceramic bricks, held on the shells by means of air cooled metallic tile holders, and is installed in a dedicated plenum chamber where is run over by an air flow from several angles of incidence in order to simulate some realistic turbine conditions. A preliminary numerical study is conducted to estimate the test article surface pressure distributions in order to evaluate the mainstream flow impact on the tile holder cooling system behaviour. A novel application of Pressure Sensitive Paint (PSP) technique is applied to evaluate the air seal cooling of the brick holder system, essential to prevent hot gas ingestion. Furthermore, infrared (IR) thermography measurements on the liner are performed using an hot mainstream flow and reproducing typical cooling flow conditions. During the tests, several thermocouples, allocated on most critic brick holder components, continuously check the metal temperature.

The problem of dissipating high heat fluxes has received much attention due to its importance in such applications as cooling of electronic equipment, micro heat exchangers and many others. The most effective way of cooling is pumping liquid inside these devices through microchannels or porous media. Advantages and disadvantages using the Infrared Technique for the study of the heat transfer in microsystems are analyzed. The generalized model for analysis using IR technique for the temperature measurement in microdevices is suggested. The model is illustrated by various examples of heat transfer determination using image analysis as the heater temperature as well direct measurement of the liquid temperature.

<p>This paper presents observations from an active infrared thermography (IRT) experiment about structural monitoring by taking advantage from solar irradiance as a clean and renewable source of energy for thermal excitation. This contributes to reduction of carbon emissions associated with maintenance of existing concrete infrastructure and ensuring their extended life, and safe operation. The models in these observations were five concrete slabs made from a typical mix used for bridge construction in the UK, with simulated subsurface void (representing the defect) at depths of 5 to 25 mm (5mm increment) at the centre of slabs, and one slab without simulated defect. This study was conducted during a sunny afternoon. A sequence of IR images was collected for each slab (six sequences in total), and these sequences were used to calculate the average thermal contrast on surface of the slabs and evaluate its variation with depth of subsurface defect. Finally, the trend of thermal contrast is compared with the trend of thermal contrast from excitation by IR heater to highlight the limitations and future research needs for subsurface damage detection using solar irradiance.</p>

Flying spot thermography can be used for crack detection in metallic, ceramic and polymer components. However, many systems and applications are still limited to lab scale. The Athena system from Intercontrole/Framatome uses a rotatable laser line which is scanned collinearly with the IR camera field of view over the component surface in multiple direction to reduce the influence of emissivity. This setup now has been industrialized with state-of-the-art components and optics design to raise both the performance and the technology readiness level. This paper presents the increased performance of the LTcam system on reference samples and some applications.

This paper presents a study on the enhancement in the boiling heat transfer (BHT) and critical heat flux (CHF) with a bare indium tin oxide (ITO) surface, few-graphene layer deposited on an ITO surface, and silicon carbide (SiC) particles deposited on an ITO surface. The experiment was conducted in atmospheric pressure using FC-72 refrigerant at saturation. Infrared (IR) thermometry was used to determine the temperature fields of the heater surfaces and CHF. The values of CHF for the graphene layer on the ITO surface and SiC deposited on the ITO heater were increased by 9% and 42%, compared to the bare ITO heater, respectively. All the heater surfaces showed hydrophilic condition with the working fluid (FC-72 refrigerant). The enhancement in the BHT coefficient and CHF was attributed to surface modifications such as the formation of microporous structures and the material properties.