Infrared Heating

AC-DC thermal converters are fabricated by depositing thin-film heaters on thin dielectric membranes on a silicon chip and by remotely sensing their temperature with radiation sensors through infrared transmissive fibers. This permits all degrees of freedom for the design of the heater for optimum frequency response. In the present design the sensitivity is quite small. With a temperature of the heater 100 K above ambient, only 5 W heats up the black spot target of the radiation sensor, resulting in an output voltage of 1.5 mV. The standard deviation of the mean of an ac-dc voltage transfer involving 12 measurements is approximately 20 2 10 06 to 50 2 10 06 .

Construction progress monitoring has been perceived as one of the key factors that prompt the achievement of a construction project. However, assessing the progress is time consuming, costly and obliges specialized personnel to reduce disagreements and approximate the actual performance to the original plan as close as possible. Image processing is a promising method that has been developed for automated monitoring of construction projects. It has attracted increasing attention for progress monitoring, quality assurance and work space analyses. Nonetheless, remarkable drawbacks still remain in image processing, particularly for outdoor environment such as construction progress monitoring. The principle downside of image processing goes back to the image resolution. Ambient lightning condition significantly affects the image quality which does affect the accuracy of data, extracted from related images. Much research strives to reduce the level of errors for data extraction but so far none has been able to deliver complete satisfactory and reliable result. In this research a novel approach based on thermal image analysis is presented. The new method consists of three phases: First, collecting the thermal and original images by utilizing Infrared-Camera. Second, estimating the position of captured images by the use of wireless sensor network implemented in the work space. Finally, the 3D plan will be updated automatically in the Building Information Modeling (BIM) software. The preliminary experimental results from an actual concrete building construction site show the feasibility of inferring the actual state of progress by the use of thermal images to overcome the limitation of vision monitoring. 

AUTOMATED CONSTRUCTION PROGRESS MONITORING USING THERMAL IMAGES AND WIRELESS SENSOR NETWORKS. Available from: https://www.researchgate.net/publication/275024236_AUTOMATED_CONSTRUCTION_PROGRESS_MONITORING_USING_THERMAL_IMAGES_AND_WIRELESS_SENSOR_NETWORKS#share [accessed Sep 11, 2015].

Evaporation is one of the inherent processes of the earth’s ecosystem. Water bodies, earth’s
surface and vegetation all contribute significantly towards the total evaporation which
eventually leads to the formation of clouds. 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.
This thesis deals with the contributors of total evaporation individually viz. open water bodies;
soil-like surfaces; and leaf-like surfaces. A ceramic infrared heater has been used to mimic the
heating due to sun’s radiation in all the experiments which were conducted in the quiescent
atmosphere. This thesis 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 immersed heaters. Heating from below leads
to unstable stratification and convection 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 unconventional porous media containing
rods, capillaries, and plates; and (3) evaporation from leaf-like surfaces. In all the experiments, a
precision weighing balance was used to measure the evaporation rate. A thermal camera was
used to get the surface temperature fields, and fluorescein dye mixed with water gave insightful
results on the evaporation process. In particular the red deposits of fluorescein particles
revealed the evaporation sites. In most of the experiments, the infrared heating was of the order
of 1000W/m2. Different sized glass and acrylic containers were used in this thesis.
Mono-disperse glass beads (closest to mimic the natural soils), stainless steel balls, sieved
natural sand and hydrophobic Ball Grid Array balls have been used to create the spheres-based
conventional porous media. Evaporation was found to undergo three stages which depended on
the spheres size and the heat flux supplied. In the 1st stage of evaporation capillary film(s) pulls
water from beneath the porous media to the top surface and the evaporation rate remained
high, close to that obtained from a water surface. Capillary break-up occurs in the transition
regime which is followed by the 2nd stage of evaporation where a new vaporization plane is
formed within the porous media. In the 2nd stage, heat is conducted through the top dried layer
to the water below where evaporation takes place and the evaporation rate drops drastically.
Transition to 2nd stage happened earlier for coarser spheres at constant heat flux. Along with the
wetting properties, the spheres size has been found to effect capillary break-up length (a
measure of capillary film strength) and hence the duration of the stages of evaporation
drastically. Surface images captured using the thermal camera clearly showed the presence of
water till the capillary break-up. The capillary break-up length was also found to be affected
significantly by the heat flux. Apart from the experimental findings of mono-disperse spheres,
two layers of different sized glass spheres have also been investigated. The presence of
complicated network of textural layering in the earth’s surface is a well-known fact. Preferential
evaporation was clearly seen in the experiments with texturally layered porous media
independent of the orientation viz. vertical or horizontal layering. The stacking positions are
found to be critical in determining the overall evaporation characteristics.
The geometry of a pore between three spheres in mutual contact is very complicated. Simpler
pore geometry would be between two rods/plates in contact or three rods in mutual contact or
stacks of either of these two. We call these types of the porous media as “Unconventional porous
media” as they possess many unique features not shown by a conventional porous media. The
evaporation characteristics of vertically stacked rods 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 length was found not to depend on the rod diameter. The capillary break-up
length for vertically stacked rods was larger than for the spheres case and was also found to be
independent of the heat flux, for the range investigated in this thesis. A mathematical model has
been developed for understanding the evaporation from the vertically stacked rods.
Experiments with horizontally stacked pencil leads showed early capillary break-up while with
horizontally stacked glass rods, capillary break-up was not observed. Experimental
investigations of porous media containing vertically stacked plates have also been studied.
Water trapped between two consecutive plates are treated as 2D source of evaporation.
Plants regulate their O2-CO2 content via tiny holes present on the leaves called “Stomata”. The
average size of a stoma is nearly 20μm and the total area covered by stomata 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. In view of this we
mimic the leaf-type using regularly spaced holes on the silicon wafers from which water
evaporates. The leaf-mimics had different hole-diameter but open area ratio was kept constant.
In all the cases 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 at lower heat fluxes. With increasing the hole-size evaporation rate was found to
decrease. The leaf-mimic with the smallest hole-size had the highest evaporation rate and the
evaporation ratio increased from 0.46 at 800W/m2 to 0.64 at 400W/m2. The 3D nature of
diffusion near these tiny holes enhances the evaporative flux which explains the high
evaporation rates even for low open area ratios.

While biologists have demonstrated the cancer killing ability of hyperthermia in combination with radiation and chemotherapy both in vitro and in vivo, clinicians find that it is difficult to raise and to keep the temperature of tumors at therapeutic levels. During the last decade, there has been significant progress in the method of heat delivery, temperature monitoring, and thermal dosimetry. In this presentation, radiofrequency (RF) and microwave heating techniques are reviewed. Examples of heating patterns of various applicators are shown to illustrate the complex energy deposition of RF and microwave energy in tissues.

Roasted pork is a favorite dish in many different cultures, and countries. At present, the roasting process is highly polluting, emitting high carbon dioxide loads to atmosphere, particulate pollution that can pollute the surrounding environment. An electric roaster is just as suitable for roasting the pork with low pollution and high efficiency but it has slow cooking capacities. So, the objectives of this research are to design and fabricate a continuous pork roaster using infrared heating for community enterprises, with its capacity and efficiency should be in an acceptable range. The designed roaster is used for production of roasted pork. The experiments are carried out on a continuous pork roaster using infrared heating. Three kilograms of pork meat are applied with the 3 infrared heaters with the power of 1000W each that give a maximum of 3000W. Capacity test results show that the production capacity of the roaster is approximately 400 pieces /hr continually. And the surface of roasted pork obtained from this roaster meet the community product standard. Therefore, if small and micro community enterprises are persuaded to use the developed roaster, it can reduce pollution from roasting process and help keep our air and environmental clean. This technology also helps to reduce cost and production time, and improve productivity, and eventually lead to be able to survive in competitive environments.

Rapid development of industrial polymer-based product requires considerable research in polymer drying. Cyclic or intermittent drying is used occasionally to save energy and improve product quality. Most published studies employ diffusion-based models. Reaction engineering approach (REA) is a lumped parameter model which is comparably simple and is now applied to cyclic situation for the first time. New definitions of equilibrium activation energy (DE v,b ) had to be introduced. With these definitions, very reasonable agreement between the predicted and published experimental data is shown. It has advantage over the diffusion model where in general complex diffusivity functions are used and had to be established using experimental data anyway. REA may be used in plant-wide simulations, where the drying kinetics has to be coupled with many other equations to be solved together. In this case, the computation time would be generally reduced if there is no need to solve the spatial distribution of water content inside the product.

Roasted pork is a favorite dish in many different cultures, and countries. At present, the roasting process is highly polluting, emitting high carbon dioxide loads to atmosphere, particulate pollution that can pollute the surrounding environment. An electric roaster is just as suitable for roasting the pork with low pollution and high efficiency but it has slow cooking capacities. So, the objectives of this research are to design and fabricate a continuous pork roaster using infrared heating for community enterprises, with its capacity and efficiency should be in an acceptable range. The designed roaster is used for production of roasted pork. The experiments are carried out on a continuous pork roaster using infrared heating. Three kilograms of pork meat are applied with the 3 infrared heaters with the power of 1000W each that give a maximum of 3000W. Capacity test results show that the production capacity of the roaster is approximately 400 pieces /hr continually. And the surface of roasted pork obtained from this roaster meet the community product standard. Therefore, if small and micro community enterprises are persuaded to use the developed roaster, it can reduce pollution from roasting process and help keep our air and environmental clean. This technology also helps to reduce cost and production time, and improve productivity, and eventually lead to be able to survive in competitive environments.

The use of infrared (IR) heating for improving the microbial safety and processing efficiency of dryroasted almonds was investigated. Almonds were roasted at 130, 140 and 150°C with three different methods: IR roasting, sequential infrared and hot air (SIRHA) roasting, and traditional hot air (HA) roasting. The heating rate and pasteurization efficacy of almonds under different roasting methods and temperatures were evaluated. Pediococcus sp. NRRL B-2354 was used as a surrogate for Salmonella enterica Enteriditis PT 30 for evaluating the pasteurization efficacy of different processing methods and conditions. When SIRHA roasting at 130, 140 and 150°C roasting temperatures was used to produce medium roasted almonds, 4.10-, 5.82-and 6.96-log, bacterial reductions were achieved with 38%, 39% and 62% time saving compared to HA roasting at each temperatures, respectively. The decimal reduction time of the bacteria at all roasting temperatures were calculated for SIRHA roasting as 8.68, 3.72 and 1.42 min, respectively, with a correlation coefficient greater than 0.92 and the thermal resistance constant was found as 25.4°C. The total color change followed zero-order reaction kinetics and the activation energies were 73.58, 52.15 and 67.60 kJ/mol for HA, IR and SIRHA roasting, respectively. No significant difference (p > 0.05) was observed in sensory quality of medium roasted almonds processed with different roasting methods. We conclude that the SIRHA roasting is a promising new method for the production of dry-roasted pasteurized almonds.

Among the technological processes that require significant energy consumption, a
significant role is played by the heating processes carried out by electric infrared
heaters. The efficiency of such heaters is defined as the perfection of the heater, that is,
its ability to most effectively convert electrical energy into infrared energy and the
ability to direct the flow of infrared radiation to the receiver as well as the perfection
of the receiver, that is, its absorptive capacity and ability to transfer heat with minimal
loss of the heated substance.

The objective of this research was to develop an infrared pasteurization process with automatic temperature control for inactivation of surface-contaminated Listeria monocytogenes on ready-to-eat meats such as hotdogs. The pasteurization system contained 4 basic elements: an infrared emitter, a hotdog roller, an infrared sensor, and a temperature controller. The infrared sensor was used to monitor the surface temperature of hotdogs while the infrared emitter, modulated by a power controller, was used as a heating source. The surface temperature of hotdogs was increased to set points (70, 75, 80, or 85 • C), and maintained for bacterial kill. The infrared surface pasteurization was evaluated using hotdogs that were surface-inoculated with a 4-strain L. monocytogenes cocktail to an average initial inoculum of 7.32 log (CFU/g). On the average 1.0, 2.1, 3.0, or 5.3 logreduction in L. monocytogenes was observed after the surface temperature of hotdogs was increased to 70, 75, 80, or 85 • C, respectively. Holding the sample temperature led to additional bacterial inactivation. With a 3 min holding at 80 • C or 2 min at 85 • C, a total of 6.4 or 6.7 logs of L. monocytogenes were inactivated. This study demonstrated that the infrared surface pasteurization was effective in inactivating L. monocytogenes in RTE meats.

We report surface hardening or crust formation, unlike caking, during drying when a confined porous medium was heated from above using IR radiation. These crusts have higher strength than their closest counterparts such as sandcastles and mud-peels which essentially are clusters of partially wet porous medium. Observed higher strength of the crusts is mostly due to surface tension between the solid particles which are connected by liquid bridges (connate water). Qualitative (FTIR) and quantitative (TGA) measurements confirm the presence of trapped water within the crust. Amount of the trapped water was ~1.5% (this is about 10 times higher than in the samples with caking) which was confirmed using SEM images. Further, in the fixed particle sizes case, the crust thickness varied slightly (10-20 particle diameters only for cases with external heating) while with the natural sand whole porous column was crusted; surprisingly, crust was also found with the hydrophobic glass beads. Fluorescein dye visualization technique was used to determine the crust thickness. We give a power law relation between the crust thickness and the incident heat flux for various particle sizes. The strength of the crust decreases drastically with increasing hydrophilic spheres diameter while it increases with higher surface temperature.

High-elevation ecosystems are expected to be particularly sensitive to climate warming because cold temperatures constrain biological processes. Deeper understanding of the consequences of climate change will come from studies that consider not only the direct effects of temperature on individual species, but also the indirect effects of altered species interactions. Here we show that 20 years of experimental warming has changed the species composition of graminoid (grass and sedge) assemblages in a subalpine meadow of the Rocky Mountains, USA, by increasing the frequency of sedges and reducing the frequency of grasses. Because sedges typically have weak interactions with mycorrhizal fungi relative to grasses, lowered abundances of arbuscular mycorrhizal (AM) fungi or other root-inhabiting fungi could underlie warming-induced shifts in plant species composition. However, warming increased root colonization by AM fungi for two grass species, possibly because AM fungi can enhance plant water uptake when soils are dried by experimental warming. Warming had no effect on AM fungal colonization of three other graminoids. Increased AM fungal colonization of the dominant shrub Artemisia tridentata provided further grounds for rejecting the hypothesis that reduced AM fungi caused the shift from grasses to sedges. Non-AM fungi (including dark septate endophytes) also showed general increases with warming. Our results demonstrate that lumping grasses and sedges when characterizing plant community responses can mask significant shifts in the responses of primary producers, and their symbiotic fungi, to climate change.

The design of a new planar or thin-film multijunction thermal converter (PMJTC) on a quartz membrane and a quartz crystal chip results in a calculable standard for ac-dc voltage transfer for frequencies from 100 kHz to 100 MHz with improved uncertainties. This is due to smaller dielectric losses and higher insulation resistance in the quartz membrane and the quartz chip. The window with the membrane is anisotropically etched into the quartz crystal chip. For the first measurements, the temperature of the heater was radiometrically sensed with a thin-film infrared sensor and later with an array of 100 Cu-CuNi thermocouples. At frequencies higher than 100 kHz, the ac-dc voltage transfer differences are one order smaller than with the standard PMJTC with the Si 3 N 4 SiO 2 Si 3 N 4 sandwich membrane on a silicon chip. Index Terms-High-frequency ac-dc transfer, planar multijunction thermal converter (PMJTC), quartz wafer.

Instrumental and sensory quality of potato strips baked in a Radiant Wall Oven (RWO) was evaluated and compared to deep-fat fried and conventional oven (CO) baked samples. Even though RWO baked potato strips had one-fourth the fat content of the deep-fat fried samples, there was no significant difference in firmness, puncture force, and chroma of RWO baked and deep-fat fried samples. Consumer acceptability of RWO baked potato strips was 65.7% and 85.7% before and after revealing the nutrition facts, respectively. Both were lower than acceptability of deep-fat fried samples. However, 36.5% of consumers were willing to purchase RWO baked samples.

Rapid development of industrial polymer-based product requires considerable research in polymer drying. Cyclic or intermittent drying is used occasionally to save energy and improve product quality. Most published studies employ diffusion-based models. Reaction engineering approach (REA) is a lumped parameter model which is comparably simple and is now applied to cyclic situation for the first time. New definitions of equilibrium activation energy (DE v,b) had to be introduced. With these definitions, very reasonable agreement between the predicted and published experimental data is shown. It has advantage over the diffusion model where in general complex diffusivity functions are used and had to be established using experimental data anyway. REA may be used in plant-wide simulations, where the drying kinetics has to be coupled with many other equations to be solved together. In this case, the computation time would be generally reduced if there is no need to solve the spatial distribution of water content inside the product.

Thermoelectric modules (TEM), also known as Peltier modules, form an interesting topic to cover in an introductory semiconductor course. They provide insight on some important semiconductor principles, namely the Seebeck effect (the reverse of the Peltier effect) and thermal conductance. This paper presents a new methodology to characterize a TEM using a custom-designed test apparatus along with a simplified method for determining the TEM's three key parameters: its Seebeck coefficient, its electrical resistance, and its thermal conductance. Results obtained using this methodology were validated by comparing the anticipated theoretical behavior of the TEM (using the experimentally determined parameters) to the actual results obtained in a vacuum environment. The suggested methodology has been evaluated by students and the results of this demonstrate its usefulness in an educational environment.

We experimentally report evaporation characteristics from leaf-like surfaces having low open (exposed) area ratio. Even at much lower (1-10%) exposed areas, higher transpiration rates (60-70% compared to a bare water source) are sustained by a leaf. We mimic stomata, tiny openings present on the leaves using holes punched on silicon wafers (SW). The leaf-mimics have different opening diameters, ranging from 50lm to 400lm, but nearly the same open area of $ 25mm 2 : The leaf-mimic with the smallest opening size was found to evaporate the most, while for the larger opening sizes it seems to decrease. In all the cases, evaporation ratio (ratio of the evaporation rate from the leaf-mimic to that of from a bare water surface at the same net incident radiation) increased with decreasing pore sizes; we compute this ratio based on three different definitions including one for the isothermal cases. In non-isothermal cases, we recognized that the variation in surface temperature led to nonlinear variation in the surface water vapor concentration. The effect of increased surface temperature, compared to a bare water surface in similar conditions, is missing in defining the evaporation ratios in previous approaches and thus we include it.

High-elevation ecosystems are expected to be particularly sensitive to climate warming because cold temperatures constrain biological processes. Deeper understanding of the consequences of climate change will come from studies that consider not only the direct effects of temperature on individual species, but also the indirect effects of altered species interactions. Here we show that 20 years of experimental warming has changed the species composition of graminoid (grass and sedge) assemblages in a subalpine meadow of the Rocky Mountains, USA, by increasing the frequency of sedges and reducing the frequency of grasses. Because sedges typically have weak interactions with mycorrhizal fungi relative to grasses, lowered abundances of arbuscular mycorrhizal (AM) fungi or other root-inhabiting fungi could underlie warming-induced shifts in plant species composition. However, warming increased root colonization by AM fungi for two grass species, possibly because AM fungi can enhance plant water uptake when soils are dried by experimental warming. Warming had no effect on AM fungal colonization of three other graminoids. Increased AM fungal colonization of the dominant shrub Artemisia tridentata provided further grounds for rejecting the hypothesis that reduced AM fungi caused the shift from grasses to sedges. Non-AM fungi (including dark septate endophytes) also showed general increases with warming. Our results demonstrate that lumping grasses and sedges when characterizing plant community responses can mask significant shifts in the responses of primary producers, and their symbiotic fungi, to climate change.

This paper presents a vision-based method to estimate the *real motion of a single camera from views of a planar patch. Projective techniques allow to estimate camera motion from pixel space apparent motion without explicit 3-D reconstruction. In addition, the paper will present the HELINSPEC project, the framework where the proposed method has been tested, and will detail some applications in external building inspection that make use of the proposed techniques.

This paper presents a vision-based method to estimate the *real motion of a single camera from views of a planar patch. Projective techniques allow to estimate camera motion from pixel space apparent motion without explicit 3-D reconstruction. In addition, the paper will present the HELINSPEC project, the framework where the proposed method has been tested, and will detail some applications in external building inspection that make use of the proposed techniques.