Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
299
result(s) for
"Heat Transmission Experiments."
Sort by:
Experiments with heat and energy
Discover scientific principles by carrying out step-by-step activities, and learn how to conduct fair tests and to record and assess results.
Book
No heat flow in charge-neutral graphene
The ground state of electrons in charge-neutral graphene in a strong magnetic field has not been conclusively identified. Thermal transport measurements narrow down the possible candidates, with evidence that the ground state does not conduct heat.
Journal Article
Photonic heat transport in three terminal superconducting circuit
We report an experimental realization of a three-terminal photonic heat transport device based on a superconducting quantum circuit. The central element of the device is a flux qubit made of a superconducting loop containing three Josephson junctions, which can be tuned by magnetic flux. It is connected to three resonators terminated by resistors. By heating one of the resistors and monitoring the temperatures of the other two, we determine photonic heat currents in the system and demonstrate their tunability by magnetic field at the level of 1 aW. We determine system parameters by performing microwave transmission measurements on a separate nominally identical sample and, in this way, demonstrate clear correlation between the level splitting of the qubit and the heat currents flowing through it. Our experiment is an important step towards realization of heat transistors, heat amplifiers, masers pumped by heat and other quantum heat transport devices.
Quantum heat transport devices are currently intensively studied. Here, the authors report the photonic heat transport modulated by superconducting qubit in a three-terminal device. Flux dependent heat power correlates with microwave measurements.
Journal Article
Ice front blocking of ocean heat transport to an Antarctic ice shelf
Mass loss from the Antarctic Ice Sheet to the ocean has increased in recent decades, largely because the thinning of its floating ice shelves has allowed the outflow of grounded ice to accelerate
1
,
2
. Enhanced basal melting of the ice shelves is thought to be the ultimate driver of change
2
,
3
, motivating a recent focus on the processes that control ocean heat transport onto and across the seabed of the Antarctic continental shelf towards the ice
4
–
6
. However, the shoreward heat flux typically far exceeds that required to match observed melt rates
2
,
7
,
8
, suggesting that other critical controls exist. Here we show that the depth-independent (barotropic) component of the heat flow towards an ice shelf is blocked by the marked step shape of the ice front, and that only the depth-varying (baroclinic) component, which is typically much smaller, can enter the sub-ice cavity. Our results arise from direct observations of the Getz Ice Shelf system and laboratory experiments on a rotating platform. A similar blocking of the barotropic component may occur in other areas with comparable ice–bathymetry configurations, which may explain why changes in the density structure of the water column have been found to be a better indicator of basal melt rate variability than the heat transported onto the continental shelf
9
. Representing the step topography of the ice front accurately in models is thus important for simulating ocean heat fluxes and induced melt rates.
The front of the Getz Ice Shelf in West Antarctica creates an abrupt topographic step that deflects ocean currents, suppressing 70% of the heat delivery to the ice sheet.
Journal Article
Investigation evaluation of thermo-hydraulic flow and heat improvement in a 3D circular corrugated pipe based on response surface method and Taguchi analyses
Current research is investigating the effect of different tube geometries on flow patterns and thermal performance. Perform numerical simulations and thermo-fluid couplings. Calculation results are calculated and the solution uses both flow transport and thermal correction. Results are compared and validated using experimental results. Hydraulic and heat flow behaviors in all corrugated tubes are studied and discussed under various constitutive parameters of position and shape. The turbulent fluid flow in these tubes is modeled using 3D numerical flow domain simulations and the optimization of the multilens algorithm is analyzed. The effects of various geometric design parameters such as ring diameter, spacing between each well ring, and number of well rings around the tubing spacing of the rings were analyzed using Response Surface Methodology (RSM) and Taguchi Method (TM). Analyzed. be studied. The effects of changes in flow structure, such as velocity magnitude and radial velocity, and velocity magnitude and radial velocity profiles in different configurations, are studied. An experimental design strategy using the Taguchi method (TM) is chosen according to the variance of the orthogonal L16 sequences. Optimization results show that higher differential pressure values are related to shaft diameter. Therefore, the number of corrugated rings has a great effect on the heat transfer rate and temperature difference. Various configurations of Conduit Performance Evaluation Factor (PEF) increased the PEF value by more than 1.3.
Journal Article
Unleashing the Neurotherapeutic Potential: The Crucial Role of miR-206-3p in Facilitating Hsp90aa1-Mediated Central Nervous System Injuries During Heat Stroke
This study aims to explore the molecular mechanisms of miR-206-3p in regulating Hsp90aa1 and its involvement in the central nervous system (CNS) injury in heat stroke. Weighted gene co-expression network analysis (WGCNA) was performed on the GSE64778 dataset of heat stroke to identify module genes most closely associated with disease characteristics. Through the selection of key genes and predicting upstream miRNAs using RNAInter and miRWalk databases, the regulatory relationship between miR-206-3p and Hsp90aa1 was determined. Through in vitro experiments, various methods, including bioinformatics analysis, dual-luciferase reporter gene assay, RIP experiment, and RNA pull-down experiment, were utilized to validate this regulatory relationship. Furthermore, functional experiments, including CCK-8 assay to test neuron cell viability and flow cytometry to assess neuron apoptosis levels, confirmed the role of miR-206-3p. Transmission electron microscopy, real-time quantitative PCR, DCFH-DA staining, and ATP assay were employed to verify neuronal mitochondrial damage. Heat stroke rat models were constructed, and mNSS scoring and cresyl violet staining were utilized to assess neural functional impairment. Biochemical experiments were conducted to evaluate inflammation, brain water content, and histopathological changes in brain tissue using H&E staining. TUNEL staining was applied to detect neuronal apoptosis in brain tissue. RT-qPCR and Western blot were performed to measure gene and protein expression levels, further validating the regulatory relationship in vivo. Bioinformatics analysis indicated that miR-206-3p regulation of Hsp90aa1 may be involved in CNS injury in heat stroke. In vivo, animal experiments demonstrated that miR-206-3p and Hsp90aa1 co-localized in neurons of the rat hippocampal CA3 region, and with prolonged heat stress, the expression of miR-206-3p gradually increased while the expression of Hsp90aa1 gradually decreased. Further in vitro cellular mechanism validation and functional experiments confirmed that miR-206-3p could inhibit neuronal cell viability and promote apoptosis and mitochondrial damage by targeting Hsp90aa1. In vivo, experiments confirmed that miR-206-3p promotes CNS injury in heat stroke. This study revealed the regulatory relationship between miR-206-3p and Hsp90aa1, suggesting that miR-206-3p could regulate the expression of Hsp90aa1, inhibit neuronal cell viability, and promote apoptosis, thereby contributing to CNS injury in heat stroke.
Journal Article
Effect of dense packed micro-/nano-porous thin film surfaces developed by a combined method of etching, electrochemical deposition and sintering on pool boiling heat transfer performance
The transportation of quick latent heat during phase change heat transfer (boiling) guides its prospective application in various heat transfer devices. The stability of the fabricated cavity/porous surfaces with the base substrate is a significant concern for the degradation of boiling performance. Therefore, a new three-step surface fabrication method (wet etching, electrochemical deposition, and sintering) is proposed in this work. Initially, the three micro/nanostructured surfaces (ES#3, ES#2, and ES#1) are fabricated by using wet/chemical etching. The best-performing wet/chemical etching surface (ES#3) is further used as a cathode for next-of-surface fabrication, i.e., electrochemical deposition. The electrochemically deposited surface (ES#4) is sintered in a predefined atmosphere to increase the bonding between the coated surface (copper-alumina) and the etching surface (ES#3). The higher boiling performance found on the final surface (ES#4) is due to the proper bonding between the ES#3 and electrodeposited copper-alumina nanoparticles. A decrease in the intermediate resistance due to proper binding boosts the percentage of heat transmission by keeping the temperature constant between the top surface of the heater and the tip of the fin. For ES#4, the critical heat flux (CHF) improvement over bare copper is 98%. Comparing the ES#4 coated surface to the bare copper surface results in a 260% increase in heat transfer coefficient (HTC). The effect of various macro and micro-scale constraints on pool boiling heat transfer phenomena is also investigated. Following multiple testing cycles, the decrease in superheat temperatures, surface morphology, and wettability for ES#4 is significantly lower, which indicates healthier stability of ES#4 surface.
Journal Article
Design and selection of suitable sustainable phase change materials for latent heat thermal energy storage system using data-driven machine learning models
The present study aims to develop and implement data-driven machine learning (ML) models for performance prediction of heat flow and specific heat of sustainable composite phase change materials (SCPCMs). The implementation of ML models is being investigated for the first time, though the usage of PCMs has been studied in many applications. In this work, five ML models, namely decision tree regression (DTR), k-nearest neighbour (k-NN), random forest regression (RFR), extreme gradient boosting regression (XGBR), and cat boost regression (CBR), are considered for predicting the heat flow and specific heat of SCPCMs. A total of 14,303 data points for heat flow and 9059 data points for specific heat are considered. Five input parameters are considered: concentration of PCM, the concentration of biochar, concentration of multi-walled carbon nanotubes (MWCNT), heating rate of the sample, and temperature of the sample. The output parameters are heat flow (mW mg
−1
) and specific heat (J g
−1
°C
−1
). From the results of performance predictions, the k-NN model exhibited the best coefficient of determination of 0.997 and 0.994 for heat flow and specific heat, respectively, among its peers. A model sensitivity analysis for heat flow prediction is performed and found that the errors between the actual and predicted values are 1.79%, 3.41%, 1.16%, 14.95%, and 1.66% for RFR, DTR, k-NN, XGBR, and CBR, respectively. Similarly, for the specific heat prediction, the error between the actual and predicted values is 0.687%, 0.99%, 0.37%, 10%, and 0.44% for RFR, DTR, k-NN, XGBR, and CBR, respectively. Thus, the developed data-driven machine learning models can be graded as k-NN > CBR > RFR > DTR > XGBR, based on their prediction accuracy and are found to be helpful in the selection of suitable sustainable PCMs for latent heat thermal energy storage systems.
Journal Article
Parametric Optimization of Entropy Generation in Hybrid Nanofluid in Contracting/Expanding Channel by Means of Analysis of Variance and Response Surface Methodology
This study aims to propose a central composite design (CCD) combined with response surface methodology (RSM) to create a statistical experimental design. A new parametric optimization of entropy generation is presented. The flow behavior of magnetohydrodynamic hybrid nanofluid (HNF) flow through two flat contracting expanding plates of channel alongside radiative heat transmission was considered. The lower fixed plate was externally heated whereas the upper porous plate was cooled by injecting a coolant fluid with a uniform velocity inside the channel. The resulting equations were solved by the Homotopic Analysis Method using MATHEMATICA 10 and Minitab 17.1. The design consists of several input factors, namely a magnetic field parameter (M), radiation parameter (N) and group parameter (Br/A1). To obtain the values of flow response parameters, numerical experiments were used. Variables, especially the entropy generation (Ne), were considered for each combination of design. The resulting RSM empirical model obtained a high coefficient of determination, reaching 99.97% for the entropy generation number (Ne). These values show an excellent fit of the model to the data.
Journal Article
The rheology and thermal history of Mars revealed by the orbital evolution of Phobos
The evolution and internal structure of Mars are, by comparison to its present-day surface, poorly known—although evidence of recent volcanic activity
1
suggests that its deep interior remains hot and convectively cooling. The cooling rate of Mars is related to its early thermal state and to its rheology, which determines its ability to deform and to dynamically evolve
2
. Attempts to reconstruct the dynamic history of Mars and reveal its present-day structure, by combining the study of thermal evolution with surface observations, are limited by the interplay between several key quantities—including temperature, composition and rheology. Here we show that by considering Phobos (the closest satellite of Mars)—the orbital evolution of which is governed by the thermochemical history of Mars, through tidal interactions—we can gain insight into the thermal history and rheology of the planet. We investigated the long-term evolution of the main envelopes of Mars; these comprise a liquid metallic core that is overlain by a homogeneous silicate convecting mantle underneath an evolving heterogeneous lithospheric lid that includes a crust enriched in radiogenic elements. By exploiting the relationship between Mars and Phobos within an established in situ scenario for the early origin of the moons of Mars
3
, we find that—initially—Mars was moderately hotter (100 to 200 kelvin) than it is today, and that its mantle sluggishly deforms in the dislocation creep regime. This corresponds to a reference viscosity of 10
22.2 ± 0.5
pascal seconds and to a moderate to relatively weak intrinsic sensitivity of viscosity to temperature and pressure. Our approach predicts a present-day average crustal thickness of 40 ± 25 kilometres and a surface heat flow of 20 ± 1 milliwatts per square metre. We show that combining these predictions with data from future and ongoing space missions—such as InSight—could reduce uncertainties in Martian thermal and rheological histories, and help to uncover the origin of Phobos.
Insights into the thermal and rheological history of Mars are generated by considering the interplay between the thermochemistry of the planet and the orbital evolution of its closest satellite, Phobos.
Journal Article