Precision radiometric surface temperature (PRST) sensor

Temperature tracing of stored red-blood-cell concentrates (RBCs) is inevitable with respect to RBC quality control. RBC temperature, which should not exceed 10°C, is usually assessed by devices attached to the surface of the RBC pouch, assuming that surface temperature adequately represents the thermal state of RBC. We investigated under which conditions this assumption is true. Eighteen thermocouples (TC) equidistantly mounted on a two-layer plastic grid were installed in a pouch to determine temperature distribution in the unit. Two TCs were attached to each side of the bag to evaluate surface temperatures. One was further installed in each investigation room to assess ambient room temperatures. Temperature distributions and time-temperature courses were measured under constant temperatures and various warming and cooling conditions. At homogeneous storage temperatures, only small gradients were measured between core and surface temperatures. Removed from cooling chamber to room temperature or back from room to storage temperature, core and surface time-temperature curves drifted apart. Surface and core temperature diverged the more, the faster ambient temperatures altered. The situation could be stabilized by thermal isolation: handled in a transport box, or even better in an air cushion envelope, surface and core courses approached and ultimately closely followed each other, respectively. RBC temperature monitoring devices attached to the surface of the RBC pouch very well describe the core temperature under constant temperature conditions. During transport, thermal isolation of the RBC unit is necessary to control RBC temperature precisely by surface temperature measurements.

: The effects of localized aerodynamic heating in cylinder expansion gaps positioned in cross flow were investigated in a shock tube. For this study, Mach number and Reynolds number were varied from 1.04 to 1.38 and 5 x 105 to 9 x 105, respectively. The cylinder was instrumented with quick response time thermocouples positioned on the surface of the cylinder, the wall of the gap, and the gap floor. Gap aspect ratios varied from 1.23 to 3.69. Pressure gauges were used to measure wave shock speeds, pressure ratios, and transient pressure conditions. Surface temperatures were measured and converted to heat fluxes using a one-dimensional semi-infinite slab model. Adiabatic wall temperatures were obtained from pressure measurements and ideal gas law relationships. Local nondimensional heat transfer coefficients, Nusselt numbers, were calculated from experimental surface and adiabatic wall temperatures. The present study found a direct dependence on Nusselt number values with Mach number. Peak heating inside the gap was determined to be a function of gap width and location on the cylinder. As gap width was reduced, the location of peak heating on the cylinder varied and Nusselt number values on the floor of the gap dominated. Shock tubes, Aerodynamic heating, Cylinder heat transfer, Heat transfer in gaps, Cylinder in cross flow.

The ignition of an air plasma by a laser pulse at the surface of a metal target may yield a large increase in the heat deposition in the target. The target surface temperature during the pulse is determined by the thermal flux from the plasma, rather than the laser-pulse parameters. The plasma prevents direct observation of the surface temperature. We show how the surface temperature can be calculated using plasma thermal-coupling models based on thermal conduction from a radially expanding plasma (due to Robin) and on thermal emission from a axially propagating plasma. The two unknown parameters of the models, the thermal-coupling coefficient and the propagation or expansion speed, can be evaluated with simple measurements of the total heat and spot-center thermal fluence depositions. The model calculations are applied to an experimental example using a 137-J 30-μs CO2 laser pulse. No discrepancy between the calculated peak surface temperatures and the observed absence of surface melting is found. The calculated values of plasma propagation and expansion speed are in fair agreement with the observed plasma development early in the pulse. The models therefore appear to be reliable for calculation of the surface thermal transient.

We introduce a method to determine the gradient between measured physical temperature and true radiating surface temperature of a passive microwave calibration target (load or blackbody). An empirical cooling-curve fit is employed to determine heat-transfer coefficients that then allow commercial finite-element software to solve for the physical temperature at the surface of the target. Only gradients in the direction parallel to the target's pyramidal structures are determined. Two target insulation thicknesses are investigated and a mean surface radiating temperature is determined. This surface temperature differs from the internally measured physical temperature by a maximum of 0.3 K in an ambient environment. Use of a thicker insulation assembly decreases this temperature bias by 0.1 K.

Effective thermal management of electronic devices using passive cooling is a significant engineering challenge. This experimental study looks at how fin material and design affect the natural convection heat transfer of heat sinks attached to a vertical aluminum plate. Four configurations were tested under steady-state conditions: a flat plate, plates with horizontal aluminium fins, vertical aluminium fins, and copper fins arranged in a V-shape. The experiments covered heater input powers from 25 to 150 W, and we measured surface temperatures with calibrated K-type thermocouples. We calculated the heat transfer coefficient, Nusselt number, and the difference between surface and ambient temperatures to assess thermal performance. This experimental study systematically investigates the influence of fin geometry and material on natural convection heat transfer from a vertically heated aluminium plate under identical steady-state conditions. Three fin materials (aluminium, copper, and brass) and three configurations (vertical, horizontal, and V-shaped fins) were examined over a heater input range of 25-150 W. Surface temperatures were measured using calibrated K-type thermocouples (± 0.5°C accuracy). The heat transfer coefficient, Nusselt number, enhancement ratio, and thermal resistance were calculated using energy balance relations. The copper V-fin configuration achieved a maximum heat transfer coefficient of 47.66 W/m2K at 150 W, representing a 30-40% enhancement compared to the plain plate. Surface temperature reduction reached 15-20% depending on heat input. All results are supported by quantitative uncertainty analysis (± 6-8%).These findings provide experimentally validated guidance for the optimization of passive natural convection heat sinks.

Satellite measurements of water surface temperature can benefit several environmental applications such as predictions of lake evaporation, meteorological forecasts, and predictions of lake overturning events, among others. Limitations on the temporal resolution of satellite measurements can restrict these improvements. A model of the diurnal variation in lake surface temperature could potentially increase the effective temporal resolution of satellite measurements of surface temperature, thereby enhancing the utility of these measurements in the above applications. As a step in this direction, herein a one-dimensional thermal model of a lake is used in combination with surface temperature measurements from the moderate resolution imaging spectroradiometer instrument aboard the Aqua and Terra satellites, along with ambient atmospheric conditions from local weather stations, to calculate the diurnal surface temperature variation for Lake Hartwell in South Carolina. The calculated solutions are used to obtain a functional form for the diurnal surface temperature variation of this lake, a result which has not been obtained heretofore. This functional form was obtained by averaging over several years worth of data and, therefore, represents the diurnal variation of surface temperature of the average day. Accordingly, attempts to use this averaged function to predict surface temperature in between satellite overpasses on any given day did not perform well due to day-to-day variations in cloud cover, wind speed, and other factors. It is possible that use of this averaged function combined with daily meteorological data may enable better performance.

Surface texture of an engine cylinder liner at the top-ring reversal point was observed by using Scanning Electron Microscopy (SEM) and optical microscopy. Experiments were conducted on a single-cylinder spark ignition engine over the engine break-in period. The surface texture of the cylinder liner was observed before and after the break-in test. The changes of surface texture and the wear mechanisms during the engine break-in were analyzed. The primary wear mechanisms were found to be abrasion and plastic deformation. Presented at the 57th Annual Meeting Houston, Texas May 19–23, 2002

Pseudomonads and lactic acid bacteria (LAB) are the most relevant organisms for assessing the effect of specific chilling time-temperature scenarios on the growth of spoilage bacteria under aerobic and anaerobic (vacuum packs) conditions, respectively. Pseudomonad growth was modelled on beef, pork and lamb carcasses, chilled to specific target surface temperatures and compared with the growth thatwould be achieved if the carcasses were chilled to a core temperature of 7°C (Regulation (EC) No853/2004). Pseudomonad growth with the combination of chilling the carcass surface to a target temperature (1-10°C for beef and lamb, and 5-10°C for pork) and transportation at that temperature plus ±1°C was also modelled for 1-48h (assuming an initial count of 1CFU/cm2). Finally, the growth of pseudomonads and LAB was modelled on meat intended for use in minced meat/meat preparations, stored at temperatures of 1-7°C (inclusive) for 1-12days. The effect of storage temperature and initial count on the time to reach 107CFU/cm2 was also investigated. The outputs suggest that chilling bovine or ovine carcasses to between 4 and 10°C surface temperature, inclusive, results in similar or lower predicted pseudomonad growth as compared to chilling to a core temperature of 7°C. The results for porcine carcasses depended on the target surface temperature and chilling curve applied. It was also predicted that pseudomonads and LAB grow steadily on meat stored at 1-7°C and LAB counts exceeded 107CFU/cm2 when stored for 11days at 7°C. It was concluded that the time-temperature chilling profiles that may be used to obtain similar or less growth to that obtained when chilling to a core temperature of 7°C is dependent on the initial contamination level.

<strong class="journal-contentHeaderColor">Abstract.</strong> The surface temperature controls the temporal evolution of the snowpack, playing a key role in metamorphism and snowmelt. It shows large spatial variations in mountainous areas because the surface energy budget is affected by the topography, for instance because of the modulation of the short-wave irradiance by the local slope and the shadows and the short-wave and long-wave re-illumination of the surface from surrounding slopes. These topographic effects are often neglected in large-scale models considering the surface to be flat and smooth. Here we aim at estimating the surface temperature of snow-covered mountainous terrain in clear-sky conditions in order to evaluate the relative importance of the different processes that control the spatial variations. For this, a modelling chain is implemented to compute the surface temperature in a kilometre-wide area from local radiometric and meteorological measurements at a single station. The first component of this chain is the Rough Surface Ray-Tracing (RSRT) model. Based on a photon transport Monte Carlo algorithm, this model quantifies the incident and reflected short-wave radiation on every facet of the mesh describing the snow-covered terrain. The second component is a surface scheme that estimates the terms of the surface energy budget from which the surface temperature is eventually estimated. To assess the modelling chain performance, we use in situ measurements of surface temperature and satellite thermal observations (Landsat 8) in the Col du Lautaret area, in the French Alps. The results of the simulations show (i) an agreement between the simulated and measured surface temperature at the station for a diurnal cycle in winter within 0.2 <span class="inline-formula">^∘</span>C; (ii) that the spatial variations in surface temperature are on the order of 5 to 10 <span class="inline-formula">^∘</span>C in the domain and are well represented by the model; and (iii) that the topographic effects ranked by importance are the modulation of solar irradiance by the local slope, followed by the altitudinal variations in air temperature (lapse rate), the re-illumination by long-wave thermal emission from surrounding terrain, and the spectral dependence of snow albedo. The changes in the downward long-wave flux because of variations in altitude and the absorption enhancement due to multiple bounces of photons in steep terrain play a less significant role. These results show the necessity of considering the topography to correctly assess the energy budget and the surface temperature of snow-covered complex terrain.

Comparative study of surface temperature of lithium-ion polymer cells at different discharging rates by infrared thermography and thermocouple

Observations of sky radiant emittance in the 600 to 1300 cm−1 (7.5‐16µ) waveband were made near Phoenix, Ariz., in the spring of 1966 in connection with radiometric measurement of soil surface temperatures. A marked diurnal fluctuation was found which appeared to be correlated with high ozone concentrations near the ground, in turn caused by local air pollution.

Methods of non-contact temperature measurement have been examined; emphasis being placed on radiation pyrometry. Such methods are vulnerable to emissivity errors unless blackbody emitters are involved. There are however several ways of minimizing these errors and the underlying theoretical principles of the major ones have been discussed. The author has developed a non-contact temperature measuring technique employing forced air convection to avoid emissivity errors. The technique exploits the phenomenon of heat transfer between a surface and air flowing over it when a temperature differential exists between the two. Two modes of temperature measurement have been examined, one involving initially unheated air and the other pre-heated air. In the former case the surface temperature is predicted from the temperature increase of the air passing over it. The pre-heated air mode, however, involves identifying a state of zero nett heat transfer between the surface and the air when the latter temperature is adjusted until it equals that of the former. Under these conditions the surface temperature may be inferred directly from a measurement of the air temperature. This latter mode has been applied successfully to temperature measurement of surfaces of cylindrical geometry. Since a requirement for temperature measurement of plane surfaces is widespread, most of the thesis has been devoted to applying the forced air convection principle (using both pre-heated and initially unheated air modes) to plane surfaces. It has involved a detailed theoretical and experimental investigation of the flow and temperature characteristics necessary for a successful implementation of the principle. On the basis of these investigations recommendations have been made for the design of instruments to measure the temperature of plane surfaces. One such instrument employing the initially unheated air mode has been constructed and installed on a strip annealing line for measuring the temperature(up to 550°C) of moving aluminium strip.

The effect of immersion in six disinfecting solutions on the surface texture of 10 impression materials was investigated. Assessment of the surface texture was based on measurement of the ability to reproduce fine detail. Impressions were taken of a roughness standard, i.e. a steel block with known roughness. After setting, the impressions were either stored at room temperature for 24 h, for control, or immediately immersed in a disinfecting agent for 60 min (in one case 10 min), and after 24 h poured with gypsum. After another 24 h, the roughness of the dies was recorded with a profilometer. Three addition-curing silicones were left unaltered by disinfection. For the remaining seven materials, the ability of detail reproduction was changed for some of the combinations of impression material and disinfecting solution. In general, this meant a reduction of detail reproduction, but occasionally an improvement of the surface texture resulted from disinfection. Changes in surface texture were most often brought about by a solution of chlorinated trisodium phosphate. It was concluded that elastomeric impression materials reproduced fine detail better than did alginates and that both types of impression material may be immersed in specific disinfecting solutions for as long as 1 h without the surface texture being impaired.

Thermographic Imaging of Lungs Procured and Transported on Ice

To increase the hydrophobicity and wear resistance of diamond-like carbon coatings by surface texturing using laser ablation process