Sensing surface temperature

Strain gauges cannot be feasibly placed over the entire surface of a product, so key points of high stress must be identified before instrumenting the product with gauges. In many cases, these critical areas are easily identified by judgment. Note that similar gauges may be used for sensing surface temperature at a point. This is most useful for product localized heat transfer. 

The thermographic sensor is used as a remote sensing radiometer when a reference target is imaged. It is usually necessary to correct for emissivity and atmospheric transmission to determine surface temperature with a reasonable degree of accuracy. 

The spectral features observed by astronomers have led to the classification of stars into seven broad classes outlined in Table 4.1, together with their surface temperatures. The highest-temperature class, class O, contains may ionised atoms in the spectrum whereas the older stars in class M have a much lower temperature and many more elements present in the spectrum of the star. Observation of a large number of the stars has lead to extensive stellar catalogues, recently extended by the increased sensitivity of the Hubble Space Telescope. Making sense of this vast quantity of information is difficult but in the early 19th century two astronomers... 

Ramesh Kumar, M.R., Muraleedharan, P.M., Sathe, P.V., 1999a. On the role sea surface temperature variability over the tropical Indian Ocean in relation summer monsoon using satellite data. Remote Sensing of Environment 70, 238-244. 

Cox and Macosko (19) have reported experimental results on measurements of the melt-surface temperature upon exit from the capillary using infrared pyrometry, which senses the radiation emitted by the hot polymer melt surface. Their work also included the numerical simulation of viscous heating in a capillary, a slit, and an annular die, using a method resembling that of Gerrard et al. (13). They used a boundary condition at the die wall in between the isothermal and adiabatic case, —k(dT/dr) = h T — To) at the wall, where 7o is the die temperature far from the melt-die interface as well as the inlet melt... 

The contrasting temperature-induced shifts of the pyroxene 1 and 2 pm bands could lead to erroneous estimates of the composition and, to a lesser extent, structure-type of a pyroxene-bearing mineral assemblage deduced from the remote-sensed reflectance spectrum of a hot or cold planetary surface if room-temperature determinative curves, such as that shown in fig. 10.5, are used uncritically. For example, remote-sensed spectra of planets with hot surfaces, such as Mercury and the Moon, would lead to overestimates of Fe2+ contents of the orthopyroxenes and underestimated Fe2+ contents of the clinopyroxenes (Singer and Roush, 1985). Planets with cold surfaces, such as Mars and the asteroids, could produce opposite results. On the other hand, the room-temperature data underlying the pyroxene determinative curve shown in fig. 10.5 may impose constraints on the compositions of pyroxenes deduced from telescopic spectra of a planet with very high surface temperatures, such as Mercury. 

With thermal surface impedance testing, heat is injected into the test objects surface from a hot gas pulse. The resulting surface temperature transient is analyzed to determine the bond quality in nearly real time. The surface temperature transients are sensed using an innovative noncontacting, emissivity-independent infrared sensor.27 This method is not adversely affected by surface blemishes or roughness. 

Control of heating may raise substantial problems, in that temperature measurement itself has difficulties, since most probes for temperature measurement themselves interact with the electromagnetic field, and are at best unreliable. Remote sensing is the best available, but has its own difficulties, in that sensors detect the surface temperature rather than that of the bulk. If the temperature of a body within a microwave field is to be... 

Another area of research that could be profitably explored is the use of remote sensing instruments to measure surface temperatures of textile assemblies. Infrared thermovision cameras have been used to visualize temperature distributions over clothed and nude persons in order to study the transport of microorganisms by convective heat flow (112). A variety of less expensive radiometers and radiation pyrometers that are used to measure and automatically control the temperature of textiles during drying and texturing (113, llU, 115) could also assess the thermal behavior of apparel and clothing assemblies and thus elucidate their contribution to thermal comfort indoors. 

Figure 17.7 New production modeled from remotely sensed sea surface temperature, a3 day composite for Monterey Bay, California. (A) AVHRR derived temperature, C, (B) modeled surface NO3, pM, (C) KNO3, h and (D) pN03, pmol 1 with superimposed contours of shipboard Nuptake data. From Kudela and Dugdale (1996).

Dugdale, R. C., Davis, C. O., and Wilkerson, F. P. (1997). Assessment of new production at the upwelling center at Point Conception, California, using nitrate estimated from remotely sensed sea surface temperature. J. Geophys. Res. Oceans 102, 8573—8585. 

The success of core-top temperature calibrations indicates that physiological state, genetic variability, and depth and seasonality of production play secondary roles to the control on the sedimentary U37 index exerted by mean annual near-surface temperature. In most cases, these factors produce errors at the level of 1.5 °C or less in the global core-top calibration. To this observer s opinion, core-top data cannot be reconciled with the large variations in the U 7 index attributed to genetic or physiological factors by some culture studies. This does not indicate that the culture data are wrong in a technical sense, but that their results cannot always be extrapolated to the natural environment (Popp et al., 1998). 

The UOR Mark 2 measurements complement remotely sensed, satellite measurements of sea surface temperature and ocean color. Although satellites provide synoptic, large area, limited-depth measurements, for a few parameters, the UOR Mark 2 provides a depth-resolved (below the eupho-... 

Not all trends are linear. The nature of the trend is determined by the data itself. Nonlinear trends can be important and frequently are more difficult to remove from the data. For example, second- and fifth-order polynomials were used previously (5i) to remove nonlinear trends in radiomet-rically sensed sea surface temperature data. Nonlinear trend removal, however, was not used in this study because the linear trend analysis proved adequate. A method suitable for the removal of nonlinear trends from underway data can be found in Reference 47. 

He ran his fingers slowly over the stones, sensing their temperature and feeling their surfaces. They were his treasure. Just handling them made him feel better. They reminded him of the old man. 

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