Thermal Probe Method Research Articles

Comparative study on thermal properties of undisturbed and compacted lateritic soils subjected to drying and wetting

Soil thermal properties are essential for investigating the thermal performance of many kinds of underground thermal engineering structure. To investigate the influences of microstructure alteration on soil thermal properties, thermal conductivity, thermal diffusivity and specific heat capacity were measured for both undisturbed and compacted lateritic clay specimens subjected to drying and wetting with the thermal probe method. Results revealed that thermal conductivity and diffusivity of undisturbed specimens were higher than that of compacted specimens. The specific heat capacity of the undisturbed and compacted specimens was roughly the same. For the same volumetric water content, thermal conductivity of specimens produced by drying was higher than that by wetting due to hysteresis effects. Test results from the scanning electron microscope and mercury intrusion porosimetry confirmed that compared with compacted specimens, the undisturbed specimens have a relatively uniform pore system that improves the extent or quality of heat transfer paths through the contact points and water bridges, thus have higher thermal conductivity. The hysteresis effects on soil thermal conductivity can be explained by the ink-bottle effect, effects of pore size distributions induced by shrinkage and swelling, and differences in the volume of entrapped air between drying and wetting.

CALIBRATION OF THE THERMAL DISSIPATION PROBE FOR ATEMOYA: (Annona squamosa x A. cherimola)

ABSTRACT When determining plant transpiration (TR) using the thermal dissipation probe method, it is necessary to calibrate the sap flow (SF) estimation equation for each species under study, and thus obtain reliable information about the water demand of crops. This study aims to calibrate the equation used to determine SF using the thermal dissipation probe for atemoya cultivation. The experiment was conducted in the experimental field of the Universidade do Estado da Bahia, Juazeiro, Northeast Brazil. Atemoya plants in the initial phase of development were transplanted into 21.5-l pots arranged on weighing platforms that acted as lysimeters. The SF was determined by the thermal dissipation probe method using 1-cm-long probes. The angular coefficient of the Granier equation was adjusted by minimizing the absolute deviations between the accumulated daily SF and TR measured using the lysimeter. The results demonstrated that the application of the Granier method is satisfactory for estimating the TR of the atemoya and that it is necessary to adjust the angular coefficient of the equation. The mean absolute error between SF and TR was 3.1%.

Thermal conductivity of steelmaking slag-based controlled low-strength materials over entire range of degree of saturation: A study for ground source heat pump systems

Controlled low-strength materials (CLSMs) with high workability and relatively high thermal conductivity can function as a thermal grout in the heat exchanger of ground source heat pump systems. The degree of saturation of CLSM strongly influences its thermal conductivity and thus affects the heat transfer capacity of the heat exchanger system. This study investigates the degree of saturation–thermal conductivity relationship of steelmaking slag-based CLSM using two sample preparation methods: a modified high-pressure membrane extractor coupled with a thermal needle probe (HP) and air-dried (AD) methods. The effect of grinding steelmaking slag on the mechanical properties and thermal conductivity of CLSM is also evaluated. The engineering properties test results indicate that ground steelmaking slag presents a positive effect on the compressive strength and thermal conductivity of CLSMs owing to the reduction of the inherent porosity and increased specific surface area of the raw steelmaking slag by the grinding. The degree of saturation and thermal conductivity have a linear relationship for both the AD and HP test methods. However, it was found that the AD method overestimates the thermal conductivity owing to the uneven distribution of the water content in the specimen. Finally, predictive equations are proposed to estimate the thermal conductivity of CLSM for the entire range of degree of saturation. Compared to the recently proposed equation, these equations are more appropriate for thermal conductivity estimation of grouting materials based CLSM, especially at low water content.

Measuring effective thermal conductivity of micro-particle porous materials in fixed bed by thermal probe method

For exploring the complex heat and mass transfer in the micro-particle fixed bed, the device to measure thermal conductivity was designed and built. The experiments showed that the error was less than 2.97% after calibrated, and reproducibility was good. Effects of particles diameters, porosity, flow rate and ion exchange on the thermal conductivity of micro-particle porous materials were investigated experimentally by thermal probe. The results indicated that the effective thermal conductivity in dry condition declined with the size of particles and porosity increase. The effective thermal conductivity in low flow rate (0.8 mL/min, 1.6 mL/min, 3.2 mL/min) is converse. The thermal conductivity of the resin particles after the ion exchange with the conditions of dry and low flow rate has not changed much. The chemical reaction and interrelated processing have no significant influence on the thermal conductivity by comparing with exchange of the ions of particles. The thermal conductivity of the soil from different areas in different ions further verified the above conclusions. The numerical simulation showed that the probe had little effect on the temperature field of fixed bed. It is a reliable and effective on-line method to measure the effective thermal conductivity of the micro-particle porous materials in fixed bed by thermal probe method.

Thermal Conductivity of Olive Cake Compost (OCC) as Affected by Moisture and Density: An Experimental and Mathematical Modeling

The behaviors of bioactive compounds treating gaseous pollutants in biofilters and in the compost used as soil amendment and in green roof buildings are controlled by their thermal properties. There is a lack of information on thermal conductivity of olive cake compost (OCC), K as affected by water content and bulk density. Thermal conductivities (K) of 40 samples of (OCC) were determined experimentally at bulk densities (400–950 kg/m3) and moisture contents (10%–90%) using a single thermal probe method. The results showed that thermal conductivity increased linearly as water content, and bulk density increased and with a decrease in air filled porosity. Simple linear relationships were developed between compost thermal conductivity and dry bulk density and the degree of saturation. The experimental values were close to those reported recently for leaf compost and green roof soils. The compost at water content of 90% showed the highest thermal conductivity (K) of 0.60 W/m.k, which indicate that compost, can be used as good cheep insulator in geothermal heat storage application and as an additional echo-friendly insulation layer in green roof building which might be considered as a good means of passive energy saving there.

Adaptability of Granier empirical formula in sap flow measurement of Populus tomentosa based on whole tree weighing method

We evaluated the adaptability of Granier's empirical formula in the measurement of trunk sap flow in Populus tomentosa. The thermal diffusion probe method (TDP) was used to mea-sure sap flow rate, and the whole tree weighing was simultaneously measured for each tree. We compared results from the Granier empirical formula with that from the whole tree weighing to find out whether Granier formula had any error in measuring the trunk sap flow of P. tomentosa. The transpiration rate by the whole tree weighing method and the temperature difference coefficient K by the thermal diffusion method were fitted with power exponential regression to establish a corrected Granier formula. Compared with the transpiration rate measured by the whole tree weighing method, sap flow rate calculated by the Granier empirical formula was underestimated by 67.7%. Therefore, a calibrated Granier correction formula of P. tomentosa was established: Fd=0.0135K0.6952(R2=0.77). The calculated result from this calibrated formula was only 3.4% lower than the transpiration rate estimated with the whole tree weighing method, which showed good consistency. Thus, the calculation of the P. tomentosa sap flow rate should be corrected when using the Granier empirical formula.

Using a 1D numerical temperature recovery model to estimate in-situ thermal diffusivity by an up-welling heat source in an artesian well

The determination of thermal diffusivity is a pre-requisite for geothermal site characterization and utilization. The temperature recovery (TR) method is a popular method for determining in-situ thermal conductivity together with the thermal response test and thermal conductivity probe methods. To determine in-situ thermal properties of the subsurface following a thermal disturbance produced by drilling processes or a heating cable within a borehole, the TR method is used to record decaying temperatures during the recovery period. However, to date, no studies exist to determine thermal diffusivity using up-welling water within a well. In this study, we introduce a 1D numerical method for estimating in-situ thermal diffusivity of the subsurface using up-welling thermal water as a heat source within an artesian well. Our numerical model includes parameters for the position of a sensor within a borehole, as well as for the thermal properties of a well casing and an annulus. Two data sets from the scientific literature were used to verify our model. Field data from the Jiashi Hot Spring in Taiwan were also used to demonstrate model suitability. Our model’s value for thermal conductivity is consistent with the range of values for saturated sand within the scientific literature. Accuracies for thermal diffusivity estimations under short disturbance/recovery period were also evaluated. The results suggest that in-situ thermal diffusivity can be accurate determined, with an error less than 10%, using a short testing period with pumping time as low as four hours and a recovery of 24 h.

Sap flow in ‘Tommy Atkins’ mango trees under regulated deficit irrigation

Knowledge of transpiration is of fundamental importance for improving irrigation management. This study measured sap flow of the 'Tommy Atkins' mango tree using Granier’s thermal dissipation probe method under regulated deficit irrigation. The work was conducted in a 10-year-old ‘Tommy Atkins’ mango orchard, irrigated by micro sprinkler, located in the Irrigated Perimeter of Ceraíma, in Guanambi, Bahia, Brazil. Sap flow measurements were carried out on three consecutive days in plants under regulated deficit irrigation, with reductions of 30 and 60% of crop evapotranspiration in three phases of fruit development; beginning of flowering to early fruit growth (Phase I), fruit expansion (Phase II) and physiological maturation of fruits (Phase III). Regulated deficit irrigation led to reduced sap flow in ‘Tommy Atkins’ mango tree.

Effect of aging on thermal conductivity of compacted bentonites

The thermal conductivity of compacted bentonite is one of the most crucial parameters for the safe operation of high-level radioactive waste (HLW) repositories where bentonite can act as a feasible buffer. In this study, the potential effects of aging on the thermal conductivity of Gaomiaozi (GMZ07) and Wyoming (MX80) bentonites were investigated experimentally. The bentonite specimens were prepared under different conditions, such as varying water content and dry density, through the static compaction method in a special mould. The water content of the compacted bentonite specimens was kept constant during curing periods of 0, 5, 15, 30, 60, and 100 d under constant volume conditions, and the thermal conductivity of the two bentonites was then measured using the thermal probe method. The test results showed that the thermal conductivity decreased with increasing aging time for both of the compacted bentonites, with a trend that decreased significantly at the early aging periods and then tended to be constant when the aging time exceeded 60 d. The effects of aging are more pronounced for specimens with higher dry densities and water contents. Mercury intrusion porosimetry (MIP) test results confirmed that the reduction in thermal conductivity with aging time could be attributed to smectite hydration within the bentonites during the aging process. With this hydration, part of the soil water moves into the interlayer spaces of smectite crystals, resulting in a decrease in the pore water outside the bentonite particles, which decreases the thermal conductivity of the bentonites.

Verification of a Heat-electric Power Conversion Mechanism with Narrow Band Gap using the Thermal-probe Method

Verification of a Heat-electric Power Conversion Mechanism with Narrow Band Gap using the Thermal-probe Method

Water consumption by an agroecosystem with shelter forests of corn and Populus in the North China Plain

Shelter forests play a significant role in farmland protection and the improvement of microclimates in the North China Plain, but controversy persists over the water relationship between shelter forest and crops. To explore whether the introduction of a protective forest aggravates the water stress of crops, we used stable isotopes to investigating the water sources of corn and its Populus shelter forest. The Penman–Monteith Model and the thermal dissipation probe methods were used to explore the evapotranspiration (ET) of a cornfield with shelter forest (CN) and a cornfield with no shelter forest (CK). The results suggested that corn and Populus exhibited considerable plasticity in depth of water uptake. Although there was no significant difference in water sources of corn between CN and CK, the corn and its shelter forest appeared to have relatively complementary water use patterns. The corn predominantly absorbed water from depths of 0–10 cm (23.4–46.7%), 10–20 cm (33.3–35.8%), and 20–40 cm (20.9–26.3%) during the early growth stages, and it then altered its water sources to depths of 10–20 cm (22.3–24.7%), 20–40 cm (23.7–28.1%), and 40–60 cm (25.7–39.0%) near the of its growth stages. However, Populus mainly obtained water from depths of 40–60 cm (19.8–24.1%), 60–80 cm (24.6–26.9%), and >80 cm (27.3–30.8%) throughout the growing season. The total ET of CN was 6.6% less than that of the CK due to the impact of the microclimate. The ET of CN was primarily from the cornfield, and to a lesser extent, from Populus shelter forest. Our results indicated that the introduction of Populus shelter forest does not increase water stress on corn, and it can reduce regional water resource consumption. For rational utilization of water resources, it would be feasible to select a reasonable arrangement of tree species to develop the Populus shelter forest compound system near corn farmlands in the North China Plain.

EXPRESS METHODS FOR ANALYSING THERMO-ELECTRIC MATERIALS AND CONVERTER CHARACTERISTICS

Objectives. Recently, there has been a sharp increase in research interest in thermoelectricity (TE) and its applications. New designs for thermoelectric converters (TEC) are being proposed and a large number of new thermoelectric materials (TEM) with a thermoelectric figure of merit Z = a 2 s / k enhanced by the nanotechnological (NT) method are obtained. (Here a , s and k are the coefficient of thermal electromotive force (EMF), the specific electrical conductivity and the thermal conductivity, respectively). As a result, the need for a sharp increase in the labour productivity of researchers working in the thermoelectric (TE) industry has emerged, especially when determining the characteristics of thermoelectric materials and thermoelectric converters, as well as when processing an increased volume of literature data. The aim of the present work is to develop a set of methods for rapid analysis of the characteristics of thermoelectric materials and thermoelectric converters, allowing the labour productivity of researchers working in the TE industry to be increased. Methods. The problem was solved by selecting well-known methods for studying TEM and TEC, based on nonstationary measurement principles and computer calculations, as well as creating new methods. Results. The result of the work was an expansion of the capabilities of the established thermal probe and Harman methods used to measure the Z parameter and its components (a , s and k). The Harman method is expanded to multistage modules, allowing for the passive compensation of thermal losses when measuring in air (the switching of thermocouples (TP) in “head to head” mode). Methods for estimating the Eg – the band gap width of the TEM – according to the curves Z = f (T , as well as the calculation of the TEC using the Lenz rule, are developed. A method is proposed for diagnosing the “phonon glass electron crystal” (PGEC) phase ( 1 ~ l ph / a << λ e / a / a) by determining the mean free paths of phonons l ph and electrons λe. (Here, a = 3 nm is the shortest interatomic distance). The method of autoelectrochemical alloying of thermoelectric materials, as well as diagnostics of nanostructures (NS), is developed by determining the “physical property-NS identity period x ” dependencies. Examples of the developed technique using for analysing the characteristics of thermoelectric materials and thermoelectric converters are given. Conclusion The possibility of a sharp increase in the labour productivity of researchers working in the TE industry is indicated. Acknowledgment. The work was carried out according to the state task No. 007-00129-18-00.

Canopy transpiration of Larix principis-rupprechtii plantation and its impact factors in diffe-rent slope locations at the south side of Liupan Mountains, China.

Based on a continuous field observation in the Larix principis-rupprechtii plantation plots, located at the upper (P1), middle-upper (P2), middle (P3), middle-lower (P4), and lower (P5) positions, in a southeast-facing slope of the Xiangshuihe watershed of Liupan Mountains, China, the stem sap flow was observed with the thermal diffusivity probe method. The soil water potential and meteorological factors were monitored from May to October, 2014. We found significant differences among slope positions in the daily forest transpiration (Tr, mm·d-1), with an order of P2 (0.975)＞P4 (0.876)＞P3 (0.726)＞P1 (0.653)＞P5 (0.628). Tr was significantly positively correlated with the daily maximum temperature (Tmax), daily mean solar radiation (SR), daily mean saturated vapor pressure deficit (VPD), potential evapotranspiration (PET), and daily mean soil water potential (Ψ), but negatively correlated with the daily mean air relative humidity (RH), daily precipitation (P), and daily minimum temperature (Tmin). According to the upper boundary line ana-lysis, significant differences were found in the degree of Tr responding to each single environmental factor among slope positions. The degree of its responses gradually decreased for average daily air temperature (T), RH, VPD, PET and Ψ, whereas increased for the SR and daily average volumetric soil water content (VSM) from the upper position to the lower. Results from regression and partial correlation analysis showed that variation of Tr was mainly controlled by VPD, PET and RH in different slope positions. Tr was also strongly affected by Ψ and T in the upper-slope positions and by SR, Tmin and VSM at the lower-slope positions. Generally, the Tr difference among slope positions was a consequence of joint contributions of soil water and meteorological factors. It is necessary to consider the changes of soil water and meteorological factors in different positions along the slope when examining slope-scale or watershed-scale forest transpiration with sap flow estimated from xylem sap flux density measurements of a particular plot.

EFFICACY OF INITIAL AND PERMANENT HEMOSTASIS OF THE ENDOSCOPIC HEMOCLIP METHOD COMBINED WITH HIGH-DOSE INFUSION OF PROTON PUMP INHIBITOR IN PATIENTS WITH PEPTIC ULER BLEEDING

Background: Peptic ulcer bleeding is one of the common medical emergencies. The hemostatic efficacy of endoscopic therapeutic modalities has been reported in many studies and frequently has been found to exceed 90%. Four groups of modalities are used in the endoscopic management of bleeding peptic ulcers: thermal probe methods, injection sclerotherapy, local spray methods, and mechanical hemostatic therapy. The endoscopic hemoclip method is a safe and effective hemostatic therapy for managing bleeding peptic ulcers. Objective: To determine the success rate of hemoclip in endoscopic hemostasis. Patients and methods: Clinical intervention study on 36 patients with peptic ulcer bleeding admitted in Can Tho Central General Hospital from May 2012 to November 2014. All the patients underwent emergency endoscopy for hemostasis by hemoclip and high-dose PPI use. Results: The success rate of initial hemostasis was 97.2%, and permanent hemostasis was 91.7%. The rates of rebleeding, surgery, mortality were 11.1%, 5.6%, 2.8%, respectively. Conclusion: Endoscopic hemostasis therapy by clipping combined with high- dose PPI is an effective, relatively safe treatment for peptic ulcer bleeding. Key words: Peptic ulcer bleeding, hemoclip, endoscopic hemostasis therapy

Combination of terahertz radiation method and thermal probe method for non-destructive thermal diagnosis of thick building walls

Non-destructive thermal diagnosis of walls is a crucial theme for the renovation of old buildings, the examination of building structures and the accreditation of new buildings. Nevertheless, there are very few diagnostic methods for the characterization of thick walls. In this study, an innovative approach that combines terahertz radiation method and thermal probe method is proposed. Firstly, a method using THz (terahertz) radiation is investigated and primary experimental results are shown. This THz radiation method has a large potential to characterize the dense building materials (concrete, plaster) in a short time. However, this method is less sensitive to the light insulating materials which are totally transparent to such THz radiation, and it is also impossible to identify the structure and layer order in the case of multilayer walls. Then, based on the classical thermal probe method, three multilayer walls formed of plaster, concrete and insulation materials which are common components of building walls are considered. A short time thermal probe method with an assumption of semi-infinite boundary condition is innovatively proposed. This thermal method is able to identify the first layer of wall and characterize light insulating materials or insulating and slightly capacitive materials. Therefore, with the two methods, both the dense materials and light insulating materials can be characterized. Finally, a combined application of the two methods is discussed and analyzed.

The influence of bamboo culm water content on sap flux measurements with thermal dissipation probes: observations and modeling

Water content fluctuations in bamboo culms significantly influence sap flux measurements with thermal dissipation probes, as indicated and quantified by experimental, monitoring and model analyses. Bamboos and other plants may substantially rely on stem water storage for transpiration. Fluctuations in wood water content (θ wood) may lead to errors when estimating transpiration based on sap flux (J s) measurements with the widely used thermal dissipation probe (TDP) method. To test the effects of θ wood on J s, we conducted a culm dehydration experiment, monitored bamboos with TDPs, and implemented a steady-state thermal model. Based on the model simulation, a mathematical correction method was built. Central to the calculation of J s, and thus a major potential source of error, is the maximum temperature difference between probes (ΔT max) which is often referred to as ‘zero flow’ conditions. In the culm dehydration experiment, we observed that ΔT max decreased when θ wood increased. In long-term field monitoring, ΔT max decreased when soil moisture content increased, potentially indicating changes in θ wood and a seasonal decrease in stem water storage. The steady-state model reproduced the θ wood to ΔT max relationship of the dehydration experiment and underlined a considerable sensitivity of J s estimates to θ wood. Fluctuations in θ wood may lead to a substantial underestimation of J s, and subsequently of transpiration, in commonly applied estimation schemes. However, our model results suggest that such underestimation can be quantified and subsequently corrected for with our correction equations when key wood properties are known. Our study gives insights into the relationship between θ wood and TDP-derived J s and examines potential estimation biases.

Theoretical and experimental study on effective thermal conductivity of pebble bed for fusion blanket

The effective thermal conductivity of breeder pebble bed as an important thermal physical parameter directly affects the thermal and mechanical properties of solid blanket. Theoretical and experimental studies on effective thermal conductivity of Li4SiO4 pebble bed were introduced in this paper. First, a theoretical model coupling the contact areas with bed strains was presented to predict the effective thermal conductivity of mono-sized pebble bed. Taken into account in this theoretical model is the influence of factors, such as properties of pebbles and gas, bed porosity, pebble size, gas flow, contact areas, thermal radiation and contact resistance. Second, experimental platforms were built up to measure the effective thermal conductivity of Li4SiO4 pebble bed. One is based on transient thermal probe method and the other is based on transient plane source method. The effective thermal conductivity of Li4SiO4 pebble bed with pebbles in a diameter of around 1mm were measured in the temperature range of RT∼550°C. The helium at 0.1MPa and air at atmospheric pressure were used as filling gas respectively to assess the influence on effective thermal conductivity of pebble bed. The comparison between the experimental results and calculation results by theoretical model was also discussed.

Water transport of native and exotic tree species in relation to xylem anatomical characteristics in low subtropical China

Exotic fast-growing tree species have been commonly planted as pioneer species to facilitate ecological restoration in South China. Their growth and resource utilization behavior related to intrinsic physiology and structural properties have profound influences on forest ecosystem. However, the contrastive research focusing on water utilization features along with xylem anatomical properties between native and exotic species is scarce in South China. The objective of this study is to investigate the sapwood anatomical characteristics and water utilization conditions of native and exotic fast-growing species, and to elucidate the relationship between sap-flux density and conduit features. We measured sap-flux density, conduit length, diameter and density of four native species (Schima superba, Michelia macclurei, Castanopsis hystrix and Castanopsis fissa) and four exotic species (Eucalyptus citriodora, Eucalyptus urophylla × grandis, Acacia auriculaeformis and Acacia mangium). Sap flux density was measured based on the Granier’s thermal dissipation probe method. The whole-tree water transport was quantified by multiplying sap-flux density by sapwood area. The measurements of conduit characteristics were conducted by using segregation and slice method. Sapwood area increased with the growing diameter at breast height (DBH) as a power function. Native species had a larger water-conducting tissue area than exotic species at the same DBH value when trees grew to a size with a certain value of DBH. The conduit diameter of exotic species was significantly larger than that of native species. Conversely, native species, such as S. superba and M. macclurei, had longer conduit length and higher conduit density than other tree species. Based on a physiological interpretation of the measured conduit characteristics, native tree species developed a safe water transport system while exotic fast-growing tree species come into being an efficient system instead. Water transport increased with the growing DBH as a power function, and the exponent for native species (1.60) was higher than that for exotic species (1.22). Under the combined impact of sap-flux density and sapwood area, native species presented a larger water transport at a larger DBH value, indicating that growth advantage of exotic fast-growing species might weaken as DBH increased.

Thermal Conductivity Measurement of Granular UO2(NO3)2 · 6H2O

Uranyl nitrate hexahydrate [UO2(NO3)2 · 6H2O] (UNH) holds interest as a potential nuclear reactor fuel for manufacturing the key medical isotope 99mTc through the production and subsequent decay of 99Mo. Fuel element design for such a production method requires knowledge of the thermal properties of the fuel material, particularly in the case of UNH, which has a significantly lower melting temperature than that of fuels being used currently. A system was designed to measure the thermal conductivity of UNH by an ASTM International standard thermal probe method. Measurements were made at four temperatures within the relevant range for the reactor system (25°C through 55°C) and with a variety of material preparations. With a fill gas of air, the results demonstrate a thermal conductivity at 25°C between 0.07 and 0.10 W · cm−1 · K−1. The results are the first step toward future studies that could lead to a more efficient reactor design with a heating source term capable of meeting the demand for 99Mo production while maintaining a safe and effective thermal margin.

Thermal Conductivity of Pyroclastic Soil (Pozzolana) from the Environs of Rome

The paper reveals the experimental procedure and thermo-physical characteristics of a coarse pyroclastic soil (Pozzolana), from the neighborhoods of Rome, Italy. The tested samples are comprised of 70.7 % sand, 25.9 % silt, and 3.4 % clay. Their mineral composition contained 38 % pyroxene, 33 % analcime, 20 % leucite, 6 % illite/muscovite, 3 % magnetite, and no quartz content was noted. The effective thermal conductivity of minerals was assessed to be about $$2.14\,\hbox {W}{\cdot } \hbox {m}^{-1}{\cdot } \hbox {K}^{-1}$$ . A transient thermal probe method was applied to measure the thermal conductivity ( $$\lambda $$ ) over a full range of the degree of saturation $$(S_{\mathrm{r}})$$ , at two porosities (n) of 0.44 and 0.50, and at room temperature of about $$25\,^{\circ }\hbox {C}$$ . The $$\lambda $$ data obtained were consistent between tests and showed an increasing trend with increasing $$S_{\mathrm{r}}$$ and decreasing n. At full saturation ( $$S_{\mathrm{r}}=1$$ ), a nearly quintuple $$\lambda $$ increase was observed with respect to full dryness ( $$S_{\mathrm{r}}=0$$ ). In general, the measured data closely followed the natural trend of $$\lambda $$ versus $$S_{\mathrm{r}}$$ exhibited by published data at room temperature for other unsaturated soils and sands. The measured $$\lambda $$ data had an average root-mean-squared error (RMSE) of $$0.007\,\hbox {W}{\cdot } \hbox {m}^{-1}{\cdot } \hbox {K}^{-1}$$ and $$0.008\,\hbox {W}{\cdot } \hbox {m}^{-1}{\cdot } \hbox {K}^{-1}$$ for n of 0.50 and 0.44, respectively, as well as an average relative standard deviation of the mean at the 95 % confidence level $$(\hbox {RSDM}_{0.95})$$ of 2.21 % and 2.72 % for n of 0.50 and 0.44, respectively.