Resulting Temperature Profiles Research Articles

Exploring heat transfer in freezing supercooled water droplet through high-speed infrared thermography

This study explores the intricate heat transfer dynamics and thermographic patterns during the phase change from supercooled liquid water to ice. Using high-resolution, high-speed infrared thermography, real-time temperature data were captured during the freezing process. The resulting temperature profiles reveal critical insights into the freezing dynamics, particularly highlighting the rapid phenomena of recalescence in supercooled conditions. Notably, this study represents the first time recalescence, a rapid and previously elusive phenomenon, captured and documented in the scientific literature. Additionally, a mathematical model is developed to describe the recalescence phase on macro scale. These findings have practical relevance for various industries, aiding in the design of more efficient anti−/de-icing technologies, refrigeration systems, weather prediction models, and cryopreservation techniques. The study also opens new avenues for further exploration in understanding phase transitions in supercooled water.

Crystallisation Dynamics in Large-Scale Extrusion Additive Manufacturing: An Analysis with and without Temperature Modification.

Large-Scale Material Extrusion (LS-MEX) is increasingly being used in small-scale production and prototyping due to its ability to create components in new temporal and spatial dimensions. However, the use of this manufacturing process poses microscopic and macroscopic challenges not encountered in previous small-scale production systems. These challenges arise primarily from the prolonged retention of heat in the material, which leads to insufficient strength in the extruded strands at the macrostructural level. As a result, the component can collapse, a phenomenon known as 'slumping'. Thermal energy also influences microstructural changes, such as crystallisation kinetics, which affect properties such as the strength and stiffness of the final product. The duration and dynamics of thermal energy are influenced by manufacturing parameters and the possible use of additional peripheral equipment, which affects component quality. In this study, the influence of thermal energy on structural processes through simulations of polyamide 6 with 40% carbon fibres (PA6 wt.%40 CF) is investigated. The results show that by adjusting the process parameters and using modification units, the thermal profile of the material can be accurately controlled, which allows the microstructural processes to be precisely controlled. This leads to the targeted modification of the macroscopic material properties. The focus of this work is on the combination of numerical simulations of the LS-MEX process with semi-empirical methods for the analysis of crystallisation processes. The application of the Nakamura model, which is used throughout similar investigations, allows a detailed description and prediction of the crystallisation kinetics during the manufacturing process. The study shows that the absolute degree of crystallisation can be determined with simplified assumptions using a combination of thermal simulations and semi-empirical approaches. It was found that the absolute degree of crystallisation increases from the outer interface of the strand to the print bed across the cross-section. This can be attributed to the specific thermal boundary conditions and the resulting temperature profiles at different points.

Design and cooling of permanent magnet generator in MW-class space closed Brayton cycle system

The closed Brayton cycle (CBC) system is a prime energy conversion technology to convert heat from the reactor to electric power for space missions due to its light weight, compact and stable operation. The CBC system incorporates a permanent magnet generator (PMG) mounted on the CBC shaft with the turbine and compressor. To ensure safe operation of the CBC system, a small fraction of the working fluid is used to provide the required cooling. In this study, four different cooling schemes used in CBC system are concluded and the key dimensions of the PMG are obtained through mechanical design theory and electromagnetic theory. Comprehensive research on the electromagnetic field and loss calculation is then performed. Furthermore, the cooling paths of the PMG are designed and the resulting temperature profiles are calculated. Finally, different cooling schemes are compared and the appropriate cooling advice is proposed.

The effect of non-ionizing excitations on the diffusion of ion species and inter-track correlations in FLASH ultra-high dose rate radiotherapy

Purpose. We present a microscopic mechanism that accounts for the outward burst of ‘cold’ ion species (IS) in a high-energy particle track due to coupling with ‘hot’ non-ion species (NIS). IS refers to radiolysis products of ionized molecules, whereas NIS refers to non-ionized excitations of molecules in a medium. The interaction is mediated by a quantized field of acoustic phonons, a channel that allows conversion of thermal energy of NIS to kinetic energy of IS, a flow of heat from the outer to the inner core of the track structure. Methods. We perform step-by-step Monte Carlo (MC) simulations of ionizing radiation track structures in water to score the spatial coordinates and energy depositions that form IS and NIS at atto-second time scales. We subsequently calculate the resulting temperature profiles of the tracks with MC track structure simulations and verify the results analytically using the Rutherford scattering formulation. These temperature profiles are then used as boundary conditions in a series of multi-scale atomistic molecular dynamic (MD) simulations that describe the sudden expansion and enhanced diffusive broadening of tracks initiated by the non-equilibrium spectrum of high-energy IS. We derive a stochastic coarse-grained Langevin equation of motion for IS from first-principle MD to describe the irreversible femto-second flow of thermal energy pumping from NIS to IS, mediated by quantized fields of acoustic phonons. A pair-wise Lennard-Jones potential implemented in a classical MD is then employed to validate the results calculated from the Langevin equation. Results. We demonstrate the coexistence of ‘hot’ NIS with ‘cold’ IS in the radiation track structures right after their generation. NIS, concentrated within nano-scale volumes wrapping around IS, are the main source of intensive heat-waves and the outward burst of IS due to femto-second time scale IS-NIS coupling. By comparing the transport of IS coupled to NIS with identical configurations of non-interacting IS in thermal equilibrium at room temperature, we demonstrate that the energy gain of IS due to the surrounding hot nanoscopic volumes of NIS significantly increases their effective diffusion constants. Comparing the average track separation and the time scale calculated for a deposited dose of 10 Gy and a dose rate of 40 Gy s−1, typical values used in FLASH ultra high dose rate (UHDR) experiments, we find that the sudden expansion of tracks and ballistic transport proposed in this work strengthens the hypothesis of inter-track correlations recently introduced to interpret mitigation of the biological responses at the FLASH-UHDR (Abolfath et al 2020 Med. Phys. 47, 6551–6561). Conclusions. The much higher diffusion constants predicted in the present model suggest higher inter-track chemical reaction rates at FLASH-UHDR, as well as lower intra-track reaction rates. This study explains why research groups relying on the current Monte Carlo frameworks have reported negligible inter-track overlaps, simply because of underestimation of the diffusion constants. We recommend incorporation of the IS-NIS coupling and heat exchange in all MC codes to enable these tool-kits to appropriately model reaction-diffusion rates at FLASH-UHDR. Novelty. To introduce a hypothetical pathway of outward burst of radiolysis products driven by highly localized thermal spikes wrapping around them and to investigate the interplay of the non-equilibrium spatio-temporal distribution of the chemical activities of diffusive high-energy particle tracks on inter-track correlations at FLASH-UHDR.

Memory and nonlocal effects of heat transport in a spherical nanoparticle

In this paper a mathematical model describing the heat transport in a spherical nanoparticle subject to Newton heating at its surface is presented. The governing equations involve a phonon hydrodynamic equation for the heat flux and the classical energy equation that relates the heat flux and the temperature. Assuming radial symmetry the model is reduced to two partial differential equation, one for the radial component of the flux and one for the temperature. We solve the model numerically by means of finite differences. The resulting temperature profiles show characteristic wave-like behaviour consistent with the non Fourier components in the hydrodynamic equation.

The impact of pre-main sequence stellar evolution on mid-plane snowline locations and C/O in planet forming discs

ABSTRACT We investigate the impact of pre-main sequence stellar luminosity evolution on the thermal and chemical properties of disc mid-planes. We create template disc models exemplifying initial conditions for giant planet formation for a variety of stellar masses and ages. These models include the 2D physical structure of gas as well as 1D chemical structure in the disc mid-plane. The disc temperature profiles are calculated using fully physically consistent radiative transfer models for stars between 0.5 and 3 M⊙ and ages up to 10 Myr. The resulting temperature profiles are used to determine how the chemical conditions in the mid-plane change over time. We therefore obtain gas and ice-phase abundances of the main carbon and oxygen carrier species. While the temperature profiles produced are not markedly different for the stars of different masses at early stages (≤1 Myr), they start to diverge significantly beyond 2 Myr. Discs around stars with mass ≥1.5 M⊙ become warmer over time as the stellar luminosity increases, whereas low-mass stars decrease in luminosity leading to cooler discs. This has an observable effect on the location of the CO snowline, which is located >200 au in most models for a 3 M⊙ star, but is always within 80 au for 0.5 M⊙ star. The chemical compositions calculated show that a well-defined stellar mass and age range exists in which high C/O gas giants can form. In the case of the exoplanet HR8799b, our models show that it must have formed before the star was 1 Myr old.

In-Cylinder Temperature Measurements in a 55-cm3 Two-Stroke Engine Via Tunable Laser Absorption Spectroscopy

Abstract In-cylinder temperature is a critical quantity for modeling and understanding combustion dynamics in internal combustion engines (ICEs). It is difficult to measure in small, two-stroke engines due to high operational speeds and limited space to install instrumentation. Optical access was established in a 55-cm3 displacement two-stroke engine using M4 bolts as carriers for sapphire rods to establish a 1.5-mm diameter optical path through the combustion chamber. Temperature laser absorption spectroscopy was successfully used to measure time varying in-cylinder temperature clocked to the piston position with a resolution of 3.6 crank angle degrees (CAD) at 6000 rpm. The resulting temperature profiles clearly showed the traverse of the flame front and were qualitatively consistent with in-cylinder pressure, engine speed, and delivery ratio. The temperature measurements were compared to aggregate in-cylinder temperatures calculated using the ideal gas model using measured in-cylinder pressure and trapped mass calculated at exact port closure as inputs. The calculation was sensitive to the trapped mass determination, and the results show that using the ideal gas model for in-cylinder temperature calculations in heat flux models may fail to capture trends in actual in-cylinder temperature with changing engine operating conditions.

Thermal Gradients through Sintered Solid State Electrolytes in Lithium-Ion Batteries

Recent advancements in research have made solid state electrolytes a strong contender for the previously common liquid electrolytes, as it enables fast charging at very high current densities without flammable liquids. High current in combination with higher ohmic resistance lead to much more heat being dissipated than in conventional Li-ion batteries. As a result, large amounts of ohmic heat are produced inside the battery. As dry electrochemical cells have much lower heat conducting capacity than liquid-containing ones, knowing the thermal conductivity of the cell components plays a crucial role in predicting the heat distribution in such a cell. Thermal conductivity was measured for three types of solid state electrolyte, Li7La3Zr2O12 (LLZO), Li1.5Al0.5Ge1.5(PO4)3 (LAGP) and Li1.3Al0.3Ti1.7(PO4)3 (LATP) at different compaction pressures. LAGP and LATP were measured in sintered condition, LLZO was measured before and after sintering the sample material. Thermal conductivity for the sintered electrolytes was measured to 0.470 ± 0.009 WK- 1m- 1, 0.5 ± 0.2 WK- 1m- 1 and 0.49 ± 0.02 WK- 1m- 1 at 3 bar compaction pressure for LLZO, LAGP and LATP respectively. Before sintering LLZO showed a thermal conductivity of 0.22 ± 0.02 WK- 1m- 1 at 3 bar compaction pressure. A simple analytical model of a lithium-ion battery cell stack was constructed to show the impact of the results obtained through the thermal conductivity measurements. It is based on a work by Richter et al. [1]. The resulting temperature profiles are shown in Fig. 1. The temperature gradients inside the cell stacks need to be considered when assessing lifetime and degradation effects as seen in other electrochemical systems [2-4]. Figure 1: Temperature of the stack center compared to the outer boundary for a) a dry separator and b) a solid state electrolyte, each with two thicknesses.

Assessment of Crystallinity Development during Fused Filament Fabrication through Fast Scanning Chip Calorimetry

Although semi-crystalline polymers are associated with considerably better mechanical properties and thermal stability compared to their amorphous counterparts, using them as feedstock for Fused Filament Fabrication still poses some major challenges. Hence, the development of printed part crystallinity during printing should be fully understood in order to control the developed weld strength, as well as part shrinkage and warpage. Infrared thermography was utilized to record the thermal history of deposited layers while printing a single-layer wall geometry, employing two PA 6/66 copolymers with distinct molecular weights as feedstock. Print settings were varied to establish which settings are essential to effectively monitor final part crystallinity. The resulting temperature profiles were simulated in a Fast Scanning Chip Calorimetry device that allows for the rapid heating and cooling rates experienced by the printed polymer. Both liquefier temperature and print speed were found to have very little influence on the total attained crystallinity. It became apparent that the build plate, set at a temperature above the polymer’s glass transition temperature, imposes a considerable annealing effect on the printed part. A reduced molecular weight was observed to enhance crystallinity even more strongly. The presented methodology proves that Fast Scanning Chip Calorimetry is an effective tool to assess the impact of both print parameters and feedstock characteristics on the crystallization behavior of semi-crystalline polymers over the course of printing.

Analytical formulation of effective heat transfer coefficient and extension of lumped capacitance method to simplify the analysis of packed bed storage systems

Analysis of the transient temperature evolution during charging or discharging of the packed bed thermal storage systems is immensely simplified with the formulation of an effective heat transfer coefficient between the solid storage materials and the heat transfer fluid. It can cut significant computational cost which is otherwise required for a complete numerical simulation. The lumped capacitance method, the simplest of the available options, is restricted only to the low Biot number scenarios and hence is seldom applicable to any real system. The formulation of the effective heat transfer coefficient allows the extension of the lumped capacitance method for moderate Biot numbers. The present work develops such a formulation to simplify the analysis of packed bed storage systems through analytical route. Earlier attempts in this direction were made through weighted average time method which is inherently restricted to the simple one-dimensional heat conduction problems. On the other hand, we find out the effective heat transfer coefficient starting from a general three dimensional analytical solution of the transient heat conduction and proceed with the well-known one term approximation which acts as the basis of the Heisler charts. The method is not dimensionally restricted and hence we can include realistic three dimensional shapes such as cuboid, short cylinder etc. in the formulation. We validate our method by comparing the resulting temperature profiles for the one-dimensional geometries which have been attempted earlier by the weighted average time method. We also provide the accuracy estimation (as a function of increasing Biot number) against the full numerical simulation for the geometries where the weighted average time is not applicable. Therefore, the current study provides the tool for an inexpensive theoretical estimation for the transient heat transfer behaviour in the thermal storage tanks which has long term design implications particularly for the large scale concentrated solar thermal power plants.

Laryngeal temperature simulations during carbon dioxide laser irradiation delivered by a scanning micromanipulator.

We use scatter-limited phototherapy techniques to calculate the time-dependent temperature profiles of incisions made with a commercial carbon dioxide laser being used to make a 1-mm incision under computer control using the Digital Acublade™ and with incisions made with the same laser under manual control. The goal is to understand the differences in the amount of lateral thermal damage that is likely from the computer-controlled incisions versus the manually controlled incisions. The temperature profiles are calculated from the absorption and scatter of light in a homogeneous material. The resulting temperature profiles are presented as videos showing how the tissue heats up and cools down with the incident laser pulses. The time-dependent thermal distributions indicate that the computer-controlled laser incision could show as little as 210μm of lateral thermal damage, whereas the manually controlled laser incisions could show as much as 375μm of lateral thermal damage. The computer-controlled laser incision is able to control laser pulses fast enough that subsequent pulses can ablate away tissue with a significant amount of residual heat from the previous laser pulse. Using the scatter-limited phototherapy techniques, we can see how a computer-controlled laser can make incisions with less thermal damage by ablating away tissue holding a significant amount of heat from the previous pulse before it has time to diffuse through the tissue. This method of heat removal from laser incisions has notbeen previously described or demonstrated.

Time-Resolved Emission Spectroscopy Measurements during the Restrike Period in Arc Plasma Torch

Simultaneous optical, spectroscopic, and electrical measurements in the region of the arc anode attachment of the water-argon plasma torch are presented. A movement of the arc attachment along the anode surface together with its restrike mode is monitored. Temporal evolution of temperature during one cycle of the restrike mode is obtained in three different axial positions in the plasma column. Resulting temperature profiles show how the position of the arc attachment influences the plasma properties.

Cooling pathways for deep Australian longwall coal mines of the future

Cooling of coal mines in the Bowen Basin, characterized by steep geothermal gradient, is presently achieved mostly through rental surface bulk air cooling in summer months. This paper argues that future mines will be required to focus their cooling resources more intensively to manage a challenging thermal environment where virgin coal temperatures over 50 °C at a depth of 500 m are expected. Currently, mine cooling systems are employed to maintain the wet bulb temperatures (WBT) to below 27 °C at which point the risks of heat stroke or other heat related issues are manageable. The capacities of these systems are in the range of 6–10 MW refrigeration power. The relationship between high working temperature environment and injury frequency rates is well established. Therefore, provision of appropriate cooling strategies and understanding their optimum performance and suitability are important to Australian coal mines of the future. This paper evaluates the underground temperature profiles of deep, gassy coal mines with propensity for spontaneous combustion and proposes the long term cooling pathways to effectively manage the thermal hazards. Thermodynamic modeling is performed on a longwall face and includes air leakage effects from goaf streams at various locations along the longwall face. The strategy summarizes the application of underground bulk air cooling, chilled water sprays on the shearer and the resulting temperature profiles. Considering the new mining projects planned for the Bowen Basin region, a review of implementable cooling strategies such as mid-gate mobile bulk air coolers (BACs), spot coolers, underground bulk air cooling and the use of chilled water to enhance the positional efficiency of cooling plants, are discussed in this paper. Finally, the comparison of ‘rental’ versus ‘ownership’ of cooling plants is analysed as part of long-term cooling strategies.

Thermal heterogeneity within aqueous materials quantified by 1H NMR spectroscopy: Multiparametric validation in silico and in vitro

We recently suggested a new paradigm for statistical analysis of thermal heterogeneity in (semi-)aqueous materials by 1H NMR spectroscopy, using water as a temperature probe. Here, we present a comprehensive in silico and in vitro validation that demonstrates the ability of this new technique to provide accurate quantitative parameters characterizing the statistical distribution of temperature values in a volume of (semi-)aqueous matter. First, line shape parameters of numerically simulated water 1H NMR spectra are systematically varied to study a range of mathematically well-defined temperature distributions. Then, corresponding models based on measured 1H NMR spectra of agarose gel are analyzed. In addition, dedicated samples based on hydrogels or biological tissue are designed to produce temperature gradients changing over time, and dynamic NMR spectroscopy is employed to analyze the resulting temperature profiles at sub-second temporal resolution. Accuracy and consistency of the previously introduced statistical descriptors of temperature heterogeneity are determined: weighted median and mean temperature, standard deviation, temperature range, temperature mode(s), kurtosis, skewness, entropy, and relative areas under temperature curves. Potential and limitations of this method for quantitative analysis of thermal heterogeneity in (semi-)aqueous materials are discussed in view of prospective applications in materials science as well as biology and medicine.

The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements

Abstract. Microwave radiometry is a suitable technique to measure atmospheric temperature profiles with high temporal resolution during clear sky and cloudy conditions. In this study, we included cloud models in the inversion algorithm of the microwave radiometer TEMPERA (TEMPErature RAdiometer) to determine the effect of cloud liquid water on the temperature retrievals. The cloud models were built based on measurements of cloud base altitude and integrated liquid water (ILW), all performed at the aerological station (MeteoSwiss) in Payerne (Switzerland). Cloud base altitudes were detected using ceilometer measurements while the ILW was measured by a HATPRO (Humidity And Temperature PROfiler) radiometer. To assess the quality of the TEMPERA retrieval when clouds were considered, the resulting temperature profiles were compared to 2 years of radiosonde measurements. The TEMPERA instrument measures radiation at 12 channels in the frequency range from 51 to 57 GHz, corresponding to the left wing of the oxygen emission line complex. When the full spectral information with all the 12 frequency channels was used, we found a marked improvement in the temperature retrievals after including a cloud model. The chosen cloud model influenced the resulting temperature profile, especially for high clouds and clouds with a large amount of liquid water. Using all 12 channels, however, presented large deviations between different cases, suggesting that additional uncertainties exist in the lower, more transparent channels. Using less spectral information with the higher, more opaque channels only also improved the temperature profiles when clouds where included, but the influence of the chosen cloud model was less important. We conclude that tropospheric temperature profiles can be optimized by considering clouds in the microwave retrieval, and that the choice of the cloud model has a direct impact on the resulting temperature profile.

Comparing canopy leaf temperature of three Central European tree species based on simultaneous confidence bands for penalized splines

Temperature is an important physical factor that is known to strongly affect biodiversity as well as ecosystems and their functioning. However, research in this area is still relatively limited; this may also be attributed to the multitude of influencing factors and the complexity of the statistics involved. This study analyzes the differences between the surface temperature of three Central European broadleaf tree species. A better understanding of these differences may help to elucidate the role of microclimate in biodiversity. We consider a time series of high-resolution thermal images taken from a meteorological observation tower and calculate mean canopy leaf temperatures for beech, ash and maple (Fagus silvatica, Fraxinus excelsior and Acer pseudoplatanus). In a first step, comparable image areas are extracted from the thermal image sections of the crown of each tree species avoiding shadow areas, branches, etc. We used an automatic segmentation technique, the Otsu thresholding. Extracted canopy leaf temperature values were then processed and the resulting temperature profiles estimated by O’Sullivan penalized splines. For comparing the differences in canopy leaf temperature over time, we propose the construction of simultaneous confidence bands. The analyses show that there are significant—though small—differences in canopy surface temperature between the three tree species.

Effect of Probe-Probe Distance on the Stability of DNA Hybrids on Surfaces.

We have used temperature gradient surface plasmon resonance (SPR) measurements to quantitatively evaluate how the stability of different types of hybrids formed with DNA probes on surfaces is affected by probe spacing. SPR sensors with different average surface densities of probes were prepared by coadsorbing probes with lateral spacers strands comprised of phosphorothioated adenine nucleotides (A15*). Increasing the fraction of A15* spacers in the immobilization solution results in larger distances between probes on the sensor, determined here using a combination of SPR and X-ray photoelectron spectroscopy (XPS) measurements. The hybridization activities of probes were simultaneously measured over a temperature range that spanned the denaturation temperature (Tm) of hybrids by applying a spatial temperature gradient across the sensor surface. The resulting temperature profiles of hybridization activity show how the stability of hybrids increases as either the distance between probes or the ionic strength of the hybridization buffer increase. Additionally, hybridization activity profiles sharpen as the spacing between probes increases, indicating more homogeneous hybridization behavior of probes. The results provide quantitative experimental data for testing theoretical models of stability, supporting models that account for both repulsive interactions between DNA strands and local variability in probe surface density.

Temperature profiles and heat fluxes observed in molecular dynamics simulations of force-driven liquid flows.

This paper concentrates on the unconventional temperature profiles and heat fluxes observed in non-equilibrium molecular dynamics (MD) simulations of force-driven liquid flows in nano-channels. Using MD simulations of liquid argon flows in gold nano-channels, we investigate the manifestation of the first law of thermodynamics for the MD system, and compare it with that of the continuum fluid mechanics. While the energy equation for the continuum system results in heat conduction determined by viscous heating, the first law of thermodynamics in the MD system includes an additional slip-heating term. Interaction strength between argon and gold molecules is varied in order to investigate the effects of slip-velocity on the slip-heating term and the resulting temperature profiles. Heat fluxes and temperature profiles from "continuum", "continuum augmented with slip-heating", and "heat conduction due to the power input by the driving force" are modeled and compared with the MD results. The continuum model can neither predict the heat fluxes nor the temperature profiles from MD simulations. While the continuum model augmented with slip-heating matches the MD heat fluxes, the resulting temperature profiles do not agree with the MD predictions. Overall the analytical model based on "heat conduction due to power input by the driving force" matches the heat fluxes from MD simulations, while the temperature profiles match MD predictions using an effective thermal conductivity that is about 70% of the thermodynamic value. Using different liquid-wall pairs affects the slip velocity, temperature jump, and the resulting thermal conductivity of the fluid, but results in similar physical observations. The inability of the MD method in mimicking continuum fluid mechanics in energy transport for force-driven liquid flows is scale independent, and it is more likely a numerical artifact.

Impact of Thermo‐Physical Data on the Modeling of High‐Pressure Polymerizations

AbstractModeling the high‐pressure polymerization of ethene is of vital importance in order to avoid costly high‐pressure experiments when it comes to process optimization and product design. However, closing the heat balance when modeling high‐pressure tubular reactors with a counter‐current jacket cooling is still difficult. In this contribution the influence of thermo‐physical properties – namely viscosity and heat capacity – on the simulation results was investigated. Various literature sources were evaluated and a variety of simulations were conducted, showing that both properties influence the resulting temperature profiles and conversions visibly, while the molecular weight distribution was not affected. Uncertainties of the heat capacity of 5 % could be compensated by varying initiator efficiency and fouling layer thickness within physically reasonable boundaries.

Intervertebral Disc Temperature Mapping During Disc Biacuplasty in the Human Cadaver

Background: Intradiscal biacuplasty (IDB) is a novel heating therapy using cooled radiofrequency (RF), which may offer relief for discogenic pain. Effective neuroablation may be achieved intradiscally at higher lesion temperatures. The safety of intradiscal heating at elevated temperatures using cooled RF has never been reported. Objective: The purpose of this study is to map the intradiscal and peridiscal temperatures when IDB is performed at increased temperature using a modified lesion approach. The resulting temperature profiles are used to assess the safety and theoretical efficacy of this approach to ablate nociceptors in the posterior annulus. Study Design: Research article. Methods: Eleven lumbar discs in a non-perfused human cadaver were treated by IDB. Temperature profiles in the disc during bipolar lesion at 50°C followed by 2 monopolar lesions at 60°C were mapped using custom thermocouples. Temperatures inside the disc, at the nerve roots, and in the midline ventral epidural space were monitored in real-time using a data-collection system with custom RF filters. Setting: Human research laboratory. Results: Higher maximum temperature was reached intradiscally, and a larger volume of tissue was exposed to neuroablative temperature (> 45°C). Temperature at the nerve roots and in the epidural space increased by 2.4°C ± 2.6°C and 4.9°C ± 1.9°C (mean ± SD), respectively, during bipolar lesion. Similarly, temperature increased by 2.2°C ± 1.9°C and 0.8°C ± 1.3°C at the nerve roots and in the epidural space, respectively, during monopolar lesion. Limitations: Limitations include the ex vivo setting which lacks perfusion and may not reproduce in vivo conditions such as cerebrospinal fluid dynamics. Conclusions: The modified treatment paradigm showed intradiscal heating is achieved and is concentrated in the posterior annulus, suggesting minimal risk of thermal damage to the neighboring neural structures. Clinical benefits should be evaluated. Key words: Spine, biacuplasty, thermal, disc, intervertebral