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FEATURES & BENEFITS

The Specific Heat sensor is the only sensor available to combine the measurement of Thermal conductivity, thermal diffusivity, and specific Heat in the same sensor.

It is Campbell Scientific datalogger compatible.

Simple, sturdy design allows for this sensor to be used in the lab or in the field.

Prewritten programs for the dataloggers and Excel macros to interpret the data quickly and easily are included.

Sensor can be used in foods, soils, and most porous materials.

1. Chronological Listing of Publications: Dual-Probe Heat-Pulse Technique

2. NEED A TURNKEY SOLUTION?


The Specific Heat sensor is the only sensor available to combine the measurement of thermal conductivity, thermal diffusivity, and specific heat in the same sensor.


SPECIFICATIONS

Accuracy: ± 5%

Dimensions: Body is 35mm long, 10mm in diameter; needles are 30mm long, 0.9mm in diameter.

Temperature Sensors: 10K Precision Thermistor

Material: epoxy body, stainless steel needles.

Heater resistance: 32 ohms (1041.5 ohms/m)

Cable length: 2m standard (additional cable available)

Accessories needed:

Heater control interface: One interface will run up to 5 sensors.

View a 56K PDF schematic diagram.

 

THEORY

The Specific Heat Sensor consists of a pair of 30mm-long stainless steel needles, spaced 6mm apart. It is a Dual Needle Heat Pulse sensor (DNHP). One needle contains an Evanohm heater, and the other contains a Precision 10K Thermistor. After the sensor needles are inserted into the sample, a current is applied to the heater for 8 seconds. The temperature rise of the thermistor is then monitored. The specific heat of the material is inversely proportional to the height of the sensed temperature rise, and the thermal diffusivity of the material is related to the time taken for the pulse peak to pass the temperature sensor. The thermal conductivity can then be computed as the product of the thermal diffusivity and the specific heat. For more information see the Specific Heat Sensor manual available from East 30 Sensors.

PUBLISHED PAPERS

Bristow, K.L., R.D. White, and G.L. Kluitenberg, 1994. Comparison of Single and Dual Probes for Measuring Soil Thermal Properties with Transient Heating. Australian Journal of Soil Res. 32:447-464

Bristow, K.L., R.D. White, and R. Horton, 1994. Measurement of Soil Thermal Properties with a Dual-Probe Heat Pulse Technique. Soil Sci. Soc. Am. J. 55:291-293

Bristow, K.L., J.R. Bilskie, G.J. Kluitenberg, and R. Horton, 1995. Comparison of Techniques for Extracting Soil Thermal Properties from Dual Probe Heat Pulse Data. Soil Sci. Am. J. 1:160

Campbell, G.S., C. Calissendorff, and J.H. Williams, 1991. Probe for Measuring Soil Specific Heat Doing a Heat-Pulse Method. Soil Sci. Soc. Am. J. 55:291-293

Kluitenberg, G.J., J.M. Ham, and K.L. Bristow, 1993. Error Analysis of the Heat Pulse Method for Measuring Soil Volumetric Heat Capacity. Soil Sci. Soc. Am. J. 57:1444-1451

Larson, T.H., 1988. Thermal Measurements of Soils using a Multi-Needled Probe with a Pulsed Point-Source. Geophysics 53:266-270.

Taylor, S.A. and Jackson, R.D. 1986. Heat Capacity and Specific Heat. In "Methods of Soil Analysis. Part 1. Physical and Mineralogical Methods." (2nd Ed.) (Ed. A. Klute) ASA Agronomy Monograph No. 9 pp.941-4

de Vries, D.A. (1963). Thermal Properties of soils. Physics of Plant Environment. (Ed. W. R. Van Wijk.) pp. 210-35 (North-Holland: Amsterdam)

 

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