Thermal Heat Flow Research Articles

Delineating Hot Zone and Lineaments within Vredefort Crater in South Africa through Aeromagnetic Data Inversions

The Vredefort Dome has undergone some geologic processes that result in changes in the temperature of the rocks. This study contributes to the discussion on the thermal effect of the impact in the area on a regional scale and also delineates the linear structures around the Dome. The outcome shows that the center of the Dome is characterized by a low Curie point depth (CPD), indicating a high-temperature status that agrees with previous temperature reports in that area. The high-temperature tendency is observed to extend south of the Vredefort dome. The center-south of the Vredefort structure has a high thermal gradient and heat flow. The fractal distribution of the Vredefort structure correlates with the multi-ring structure around the Dome, which is peculiar to a few impact structures on Earth. The trend of the Fractal exponent contour around the center suggests that the contact of the meteoritic body at that region occurs at an angle and then pushes southwards. The structural analysis results show linear structures that are believed to be faults/fractures trending in North-NorthEast (NNE), NorthEast (NE), EastWest (EW), and NorthSouth (NS) directions whose effects have been explained in previous works in the area and were also identified on the ground. Some closures are observed at the center of the multi-ring structure, indicating the melt-dykes around the Vredefort dome. The Euler depth solutions cluster suggests the lineaments are about 7 km deep.

APPLICATION OF MODULAR CSIPS TO TRADITIONAL KOREAN HANOK TIMBER STRUCTURES FOR THERMAL AND ENERGY PERFORMANCE

ABSTRACT This study examines the thermal and energy performance capabilities of composite structural insulation panels (CSIPs) for traditional Korean architecture, specifically Hanok. Hanok buildings, renowned for their cultural and architectural significance, often face thermal efficiency and energy consumption challenges. This research aims to explore the environmental potential of CSIPs to improve the thermal performance of Hanok structures while maintaining the traditional aesthetics of these buildings. Simulations were conducted to analyze the thermal behavior, heat flow, and energy use intensity (EUI) by wall cases of Hanok buildings, applying continuous-fiber-reinforced thermoplastic composites as a type of CSIP. The findings demonstrated that applying continuous-fiber-reinforced thermoplastic composites (CFRTCs) to the target Hanok building significantly enhanced the thermal performance, including the thermal bridge and envelope airtightness, as these composites can reduce the thermal conductivity and minimize heat loss, thus improving the insulation capabilities. Furthermore, adopting modular CSIPs in Hanok architecture offers environmental benefits and aligns with sustainability and constructability goals. By reducing reliance on mechanical heating and cooling systems, CSIP-enhanced Hanok buildings can contribute to lower energy consumption and greenhouse gas emissions. This simulation study highlights the significant potential of CSIPs with fiber-glass-reinforced thermoset (FRT) polymer skins to enhance the thermal and energy performance of traditional Korean Hanok buildings. CSIPs as applied to the target Hanok can potentially reduce heating energy consumption by approximately 21% to 29%, leading to overall energy savings of about 4% to 5% in site EUI and CO2 emissions levels per unit area.

Geothermal parameter assessment in the Southwestern Sokoto Basin, Nigeria, using spectral analysis (centroid method)

This study utilized spectral analysis (centroid method) to assess geothermal parameters in the southwestern part of the Sokoto Basin, Nigeria. The high-resolution airborne data comprised forty-nine (49) overlapping blocks, and each block was divided into 55x55 km to evaluate essential parameters such as depth to the top boundary (Zt ), centroiddepth (Zo), and magnetic source bottom (Zb = 2Zo-Zt ). The analysis revealed variable Curie points depths (CPD), ranging from 3.89 km to 26.56 km. The lowest CPD is primarily associated with basement rocks within anomalies A, B, C, D, E, F, G, H, and I, with an average CPD of 9.16 km. Furthermore, the thermal gradients ranged from 21.84 ◦C/km to 149.10 ◦C/km, with an average thermal gradient of 73.30 ◦C/km. The heat flow exhibited variations between 54.81 mW/m² and 374.24 mW/m², with average heat flow of 180.4 mW/m², indicating significant geothermal potential zones. The high thermal gradients and heat flow regions were identified, around anomalies A, B, and C. Additionally, temperature gradients identified at shallow depths ranged from 110 ◦C/km to 150 ◦C/km. The results reveal the presence of high-temperature points and anomalous geothermal potentials, particularly within anomalies A, B, and C, thus requiring further for sustainable geothermal energy generation in the study area.

Greener approach for the synthesis of Ag decorated ZnO–CeO2 nanostructure using Moringa oleifera LE and its investigation as photocatalyst for degradation of ciprofloxacin and methylene orange

Green synthesis of silver decorated ZnO–CeO2 nanostructure (Ag@ZnO–CeO2 NS) mediated Moringa oleifera LE and its photocatalytic potential against ciprofloxacin antibiotic and Methylene orange dye under sunlight. The synthesized ZnO–CeO2 and Ag@ZnO–CeO2 NS were characterized using X-ray diffraction (XRD) analysis. The crystallite size and crystallinity were calculated to 74 nm and 89% respectively using XRD analysis. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Ag, Zn, Ce and oxygen vacancies in green synthesized Ag@ZnO–CeO2 NS. Also, PL spectroscopy analysis showed the oxygen vacancies due to defects in nanostructure. The bandgap of prepared nanostructure was calculated to 2.0 eV by UV–visible spectroscopy analysis. Ag@ZnO–CeO2 NS average particles size was evaluated to 40 nm by scanning electron microscopy (SEM) analysis and energy-dispersive X-ray (EDX) analysis confirmed the presence of Ag, Zn and Ce in nanostructure. The Ag@ZnO–CeO2 NS showed an excellent Brunauer-Emmett-Teller (BET) surface area of 165 m2g-1 and 15 nm of pore diameter. Moreover, Fourier transform infrared (FTIR) spectroscopy was used to analyze chemical bonding and interaction and RAMAN spectroscopy confirmed the presence of oxygen vacancies. The thermal decomposition and heat flow was accessed by thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) The Ag@ZnO–CeO2 NS demonstrated great potential for environmental remediation which offered effective approach for the removal of Ciprofloxacin antibiotic and Methylene orange dye from wastewater with 74% and 85% photocatalytic activity respectively. The stability of catalyst after 5 cycles of reusability was evaluated by XRD analysis which showed the crystalline structure. This research contributes to the development of advanced nanomaterials with improved photocatalytic properties and the removal of emerging contaminants.

Valorisation and Thermal Responsiveness of Lignin from Elaesis guineensis

In recent years, advancement in material technology and a better understanding of material propertiescoupled with the quest for bio-compactible materials has driven research towards valorisation of agro-waste like empty palm fruit bunch (EPFB). Elaesis guineensis was a potential source of biomass and was classified as an environmental pollutant and disposal burden. In this study, the valorisation of Elaesis guineensis and its thermal responsiveness as lignin for use as a filler in polymer composites are examined. Lignin from EPFB was extracted via acid hydrolysis, using Di ethyl ether ((C2H5)2O) and HCl as the pretreatment solvent. The thermal stability, crystallinity, heat flow, chemical composition, and functional group of the extracted lignin were studied for treated and untreated EPFB samples using techniques like; Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X- ray diffrraction (XRD), X-Ray Fluorescence Spectroscopy (XRF) and Differential Scanning Calorimetry (DSC). The percent yield of 23% obtained in this work is within the range specified in literature (20.1-23.8%) using sodium hydroxide(NaOH) and calcium hydroxide (Ca (OH)2) for alkali treatment. Results of the FTIR analysis of all samples in reference to the wave numbers of lignin are in good agreement with those stated in the literature. The stretching patterns alsoindicate the presence of compounds like phenols, hydroxides, and methyl groups, which are characteristics of lignin compounds. By comparing with the cellulose standard available in the database of the XRD system, two main peaks were observed from the XRD patterns at 2θ = 22.3 and 2θ = 26.7 representing peak 002 for hemicellulose and 011 for lignin, respectively corresponding to the amorphous region of hemicellulose and lignin while peaks I002 represent the crystalline region of cellulose. From the study, it was inferred that the thermal stability of extracted lignin with a Tg of 400C is higher compared to the samples treated with di ethyl ether and untreated EPFB having a Tg of 200C. The extracted lignin has a maximum decomposition temperature of 400oC, which makes it suitable as a filler in polymer composites.

Review of methods and devices for determining the resistance to heat transfer under natural conditions

The purpose of this study is to review modern methods of determining the resistance to heat transfer of building envelopes under natural conditions using experimental equipment. Methods for experimental determination of the resistance to heat transfer given in regulatory documents have been considered. Golunov S.V. and co-authors developed a method of determining the resistance to heat transfer based on thermal imaging examination with the placement of sensors on the surfaces of the building envelopes. Abramova E.V. together with other researchers created a method of thermal non-destructive testing using a thermal imaging system, temperature and heat flow sensors. The possibility of experimentally determining the reduced resistance to heat transfer of external building envelopes under summer operating conditions using the device developed by A.E. Rusanov’s with co-authors has been described. Wang Xin et al. proposed a device for determining the resistance to heat transfer of building envelopes with improved accuracy. As a result of the analytical review, it was concluded that the presented methods make it possible to measure the resistance to heat transfer of external building envelopes when modeling various stationary and non-stationary heat transfer processes.

Evaluating Construction Projects’ Alternatives Using Lean Construction and Sustainability Principles in an Information Model Framework

This study evaluates and validates how BIM functionalities can foster the consideration of lean construction and sustainability principles in building design. To this end, a plugin was developed and implemented in a BIM-enabled visualization environment. This system aims to help a user decide the best design between alternatives, while considering the user’s perspective on what generates value in the project. To illustrate and validate the usability and importance of the system, the design of a warehouse with specific requirements was considered. Four design alternatives were modeled considering different types of superstructures, building envelopes, and materials. The system imported an external database and calculated the general costs, CO2 emissions, and thermal comfort indicators for each model. It also incorporated user-defined weights for each indicator and graphically displayed the results indicating the best options through a multiple attribute decision method. From the obtained results, it was concluded that it is possible to integrate BIM and lean principles to support sustainable development in the construction industry. Through an experiment with warehouse alternatives, the proposed approach revealed that the best project could save nearly 50% of CO2 emissions when compared to the worst project and that the second-best project had the best performance in terms of thermal heat flow (1.80 Megawatts). The results also indicate that the system can be a great asset in supporting the decision-making process of selecting the best design alternative and understanding the impact of design changes on cost and on the environment.

Technique and results of determination of vertical variations in rock thermal properties, temperature gradient and heat flow

The paper describes the results of experimental geothermal studies of the formation surrounding Savitskaya-300 well (depth 3555 m) drilled in the Volga-Ural oil and gas basin (Orenburg region, Russia). The work was aimed, firstly, at obtaining geothermal data for basin modeling and, secondly, at improving the instrumental and methodological foundations of experimental studies. Continuous core profiling of the rock thermal conductivity, volumetric heat capacity, and thermal anisotropy was performed on all 2886 recovered core samples with the total length of 329.1 m. Additional measurements were conducted at fluid saturation and elevated temperatures. For non-cored intervals, the rock thermal properties were determined from well-logging data and via measurements on rock cuttings. The studied formation is characterized by high thermal heterogeneity at both the level of strata (horizons) and individual samples. Significant thermal anisotropy up to 1.50–1.66 in the lower part of the well has been observed. To obtain data on vertical variations of equilibrium temperature and its gradient, temperature logging was performed 7 times within the 2 to 186 days of well shut-in. New data on the recovery of temperature and its gradient after drilling are important for the practice of applied and fundamental geothermal surveys. A significant increase in heat flow with depth was established based on the results of temperature gradient and rock thermal conductivity determination for 34 depth intervals. The observed general vertical variation in the whole depth range of the well up to ∼3.3 km depth can be attributed to paleoclimatic effect in the Late Pleistocene-Holocene, while the sharp increase in heat flow at ∼3.3 km within Fransian sediments is possibly due to advective heat transfer by fluid filtration. The apparent heat flow was established to be 84.3 mW⋅m−2 in the lower section of the well, below 3.3 km. The value may be close to the steady-state heat flow value, which is 84% higher than the previous published average data for the studied area.

Analysis of the geothermal formation mechanisms in the Gonghe Basin based on thermal parameter inversion

Gonghe Basin is the most critical distribution area of hot dry rock (HDR) geothermal resources in China. Geophysical results (resistivity, velocity, density, etc.) provide an indirect way to image the spatial distribution to understand its genesis, which has a multisolution problem. However, heat flow and thermal conductivity are the most direct and reliable evidence to reveal the distribution of geothermal resources. The conventional thermal conductivity and heat flow obtained based on geologic surveys and rock samples are highly accurate, but it is challenging to characterize the regional distribution characteristics. In this paper, we develop the heat transfer adaptive finite-element equation parameter inversion workflow to invert the thermal parameters and analyze the geothermal formation mechanisms in the Gonghe Basin. First, the synthetic model test verifies that our inversion process has reliable accuracy and strong antinoise ability. For the Gonghe Basin HDR geothermal example, we use high-precision aeromagnetic data to estimate the Curie depth using the improved Parker-Oldenburg method. Then, the regional conductivity thermal and temperature field can be established according to the empirical formula as the initial input model for the inversion procedure. In addition, we collect the temperature data of six HDR geothermal wells across the Gonghe-Guide Basin as a priori constraint information. Combined with the inverted thermal parameters (thermal conductivity, geothermal gradient, and heat flow), geologic structure, and geophysical result, we infer that the high thermal conductivity layer at a depth of 5–10 km provides the main deep heat source channel and the shallow low thermal conductivity fine sandstone layer of Neogene provides good caprock protection for forming a high-temperature geothermal reservoir.

Strong Variability in the Thermal Structure of Tibetan Lithosphere

AbstractWe present a model of thermal lithospheric thickness (the depth where the geotherm reaches a temperature of 1300°C) and surface heat flow in Tibet and adjacent regions based on a new thermal‐isostasy method. The method accounts for crustal density heterogeneity, is free from any assumption of a steady‐state lithosphere thermal regime, and assumes that deviations from crustal Airy‐type isostasy are caused by lithosphere thermal heterogeneity. We observe a highly variable lithospheric thermal structure which we interpret as representing longitudinal variations in the northern extent of the subducting Indian plate, southward subduction of the Asian plate beneath central Tibet, and possible preservation of fragmented Tethyan paleo‐slabs. Cratonic‐type cold and thick lithosphere (200–240 km) with a predicted surface heat flow of 40–50 mW/m2 typifies the Tarim Craton, the northwest Yangtze Craton, and most of the Lhasa Block that is likely refrigerated by underthrusting Indian lithosphere. We identify a “North Tibet anomaly” with thin (<80 km) lithosphere and high surface heat flow (>80–100 mW/m2). We interpret this anomaly as the result of removal of lithospheric mantle and asthenospheric upwelling at the junction of the Indian and Asian slabs with opposite subduction polarities. Other parts of Tibet typically have intermediate lithosphere thickness of 120–160 km and a surface heat flow of 45–60 mW/m2, with patchy anomalies in eastern Tibet. While different uplift mechanisms for Tibet predict different lithospheric thermal regimes, our results in terms of a highly variable thermal structure beneath Tibet suggest that topographic uplift is caused by an interplay of several mechanisms.

Geothermal resources assessment using temperature–depth relationships in the fault-controlled hydrothermal system of Aristino-Traianoupolis area, Northern Greece

Aristino-Traianoupolis area hosts one of the most significant water-dominated low-temperature geothermal fields in Greece. It is located on the southwestern uplifted margin of the Tertiary Evros Delta molassic basin, 10 km east of the town of Alexandroupolis (Thrace, NE Greece). The upper hydrothermal system of the Aristino Geothermal Field (AGF), one of the most promising in continental Greece, contains fluids with temperatures ranging from 51 to 99 °C, within a series of overlapping aquifers at very low depths (100–430 m). The main geothermal anomaly for temperatures higher than 90 °C covers an area of 6 km2, to a maximum prospected depth of 500 m below ground surface. The scattered regional anomaly exceeds 50 km2 and is characterized by excessively high and abruptly changing thermal gradient (42 to 450 °C/km) and heat flow (80–800 mW/m2), that are both typical of a fault-controlled hydrothermal system. Since 1993, the AGF has undergone non-systematic geothermal investigation, with emphasis on low-depth (100–500 m) drilling. This paper provides, for the first time, a synthetic and detailed evaluation of all available temperature data gathered in the last 25 years. The steady-state temperature logs reveal the dominant role of conduction for the upper geothermal system, accompanied, in most cases, by rapidly changing and abnormally high thermal gradients (100–450 °C/km), triggered, most probably, by a deeper system of higher temperature. This hypothesis is also supported by the applied chemical geothermometers, which suggest initial fluid temperatures at 140–150 °C, the hydrochemical characteristics of the fluids hosted in the deeper and most promising investigated reservoir (ignimbrite) of the upper system, and the extrapolated temperatures from the conductive temperature–depth profiles. The lower widespread medium enthalpy hydrothermal system should extend at depths 500–1000 m within volcanics and the expected Eocene limestones and basal clastic series of the Tertiary sequence that have filled the basin. Nevertheless, these assumptions need to be verified by appropriate investigations and new drillings at depths greater than 600–700 m, which would confirm the presence of a productive medium enthalpy reservoir.

Estimation of Curie-Point Depths and Heat Flow from Spectral Analysis of EMAG2 Magnetic Data in Cyprus Island

This study aims to determine Curie point depth (CPD), Heat flow and the boundaries of geological structures of Cyprus Island using EMAG2 magnetic data. CPD values were calculated by applying spectral analysis technique to magnetic anomaly map divided into 60 blocks (60x60 km2). Then, different thermal conductivity values (K=1, 1.5 and 2.5 Wm–1 K–1) and heat flow values were calculated using CPD values. CPD values ranged from 12.4 km to 28.18 km, and heat flow values were calculated between 20 and 50 mW/m2 for K=1. Shallow CPD values (CPD< 15km) were calculated in Polis, Morphou Bay, in the area between Larnaca and Famagusta and north of Kyrenia. Heat flow values are relatively high in these areas which can be researched in detail in terms of potential geothermal. In the final phase of the study, the boundaries of buried geological structures were determined by Analytic Signal (AS), Total Horizontal Derivative (THDR) and Tilt angle (TA) methods. Moho depth, Curie-Moho difference, 2D cross-correlation map of Moho and Curie depths and Earthquake distribution map are used for interpretation of the tectonic regime. Moho-Curie difference is roughly 0 and the 2D cross-correlation map produces higher (0.60-0.75) values in the southern part of the study area which might be evaluated as a passive crust. It is possible to say that few earthquakes are observed where the difference is around 0.

Synthesis, Characterization, and 3D Printing of Silver Nanoparticles/Photopolymer Resin Composites

Recent advancements in the synthesis, functionalization, and processing of metal nanoparticles to enhance the properties of polymers have gained interest in the research community. Researchers have conducted several studies to exploit the extraordinary properties of metal nanoparticles, especially when mixed with polymers. This study investigates the adaptability of synthesized polymer resin nanocomposites, tailoring the physical and thermal properties of photopolymer resins with controlled dispersion of silver nanoparticles (AgNPs) for stereolithography (SLA) 3D printing (3DP). SLA resin composed of polymethylmethacrylate (PMMA) was altered with varying concentrations of AgNPs (0.2%, 0.5%, 2%) through ultrasonication and mechanical mixing. The synthesized photopolymer resin nanocomposites were optimized for 3DP process parameters (i.e., layer resolution, laser power, and exposure time) to 3D print the samples successfully for customized photopolymer resins. The 3D printed samples were then analyzed for thermal stability using thermogravimetric analysis (TGA), while the viscosity variation was observed through a dynamic viscosimeter. It was concluded that optimization of 3DP process parameters is vital to achieving successful 3DP of metal nanoparticles reinforced photopolymer resins, which highly depends upon the physical properties of the resins. In addition, the introduction of AgNPs to photopolymer resins has considerably increased the thermal performance and heat flow characteristics.

Curie Point Depth Analysis of Lesugolo Area, East Nusa Tenggara, Indonesia Based on Ground Magnetic Data

The Curie point depth, or magnetic basal depth, of the Lesugolo geothermal area in Ende, Flores Island, East Nusa Tenggara, Indonesia was estimated by performing spectral analysis on spatial magnetic data and transforming it into the frequency domain, resulting in a link between the 2D spectrum of magnetic anomalies and the depths of the top and centroid of the magnetic sources. Shallow Curie point depths of 16 to 18 km were found in the north-northeast to southeast areas of Lesugolo, while deeper depths of 24 to 26 km were found in the southwest. The tectonic setting beneath the central part of Flores Island governs the distribution of the Curie point depths in the area. Shallow Curie point depth zones are associated with high thermal gradients (30 to 34 °C/km) and heat flow (80 to 100 mW/m2). Deep depths, on the other hand, correspond to zones of low thermal gradient (21 to 26 °C/km) and low heat flow (65 to 80 mW/m2). Both the derived thermal gradient and the heat flow maps contribute to a better understanding of the Lesugolo geothermal system’s configuration. This study suggests that the Lesugolo geothermal area’s prospect zone is located in the center of the investigated area, where the Lesugolo normal fault forms its southeastern boundary.

Thermal and Conjugate Heat Transfer Analysis of Exhaust Manifold of Multi-cylinder IC Engine

The exhaust manifold of multi cylinder IC engine is kept in between the engine block and the catalytic converter. So the exhaust manifold is exposed to very high temperature and care should be taken at the critical zone during the design stage. At several critical zones of the exhaust manifold, large compressive deformations are generated at elevated temperatures and tensile stresses remain at cold conditions. The thermal analysis will help in estimating the deformations and stress concentrations due to thermal loads. Therefore, the main aim of this study is to perform thermal analysis and conjugate heat flow analysis of an exhaust manifold of a multi-cylinder engine. The 3D model is generated using SolidWorks and analysis is carried out using Ansys workbench. Materials like grey C.I., aluminium nitride, silicon nitride, and stainless steel are used in this analysis. The results of total heat flux, directional heat flux and temperature distribution were compared. Silicon nitride material is suggested to be the suitable material for engine exhaust manifolds based on the material mechanical properties and thermal distribution-related thermal stress developed on the exhaust manifold.

Advanced Determination of Heat Flow Density on an Example of a West Russian Oil Field

Reliable geothermal data are required for basin and petroleum system modeling. The essential shortcomings of the methods and results of previous geothermal investigations lead to a necessity to reappraise the data on the thermal properties and heat flow. A new, advanced experimental basis was used to provide reliable data on vertical variations in the thermal properties of formation and heat flow for the area surrounding a prospecting borehole drilled through an unconventional hydrocarbon reservoir of the Domanik Formation in the Orenburg region (Russia). Temperature logging was conducted 12.5 months after well drilling. The thermal properties of the rocks were measured with continuous thermal core profiling on all 1699 recovered core samples. Within non-cored intervals, the thermal conductivity of the rocks was determined from well-logging data. The influence of core aging, multiscale heterogeneity and anisotropy, in situ pressure and temperature on the thermal properties of rock was accounted for. The terrestrial heat flow was determined to be 72.6 ± 2.2 mW·m−2—~114% larger than the published average data for the studied area. The experiment presents the first experience of supporting basin modeling in unconventional plays with advanced experimental geothermal investigations.

Impact of Nanofluid Flow over an Elongated Moving Surface with a Uniform Hydromagnetic Field and Nonlinear Heat Reservoir

The increasing global demand for energy necessitates devoted attention to the formulation and exploration of mechanisms of thermal heat exchangers to explore and save heat energy. Thus, innovative thermal transport fluids require to boost thermal conductivity and heat flow features to upsurge convection heat rate, and nanofluids have been effectively employed as standard heat transfer fluids. With such intention, herein, we formulated and developed the constitutive flow laws by utilizing the Rossland diffusion approximation and Stephen’s law along with the MHD effect. The mathematical formulation is based on boundary layer theory pioneered by Prandtl. Governing nonlinear partial differential flow equations are changed to ODEs via the implementation of the similarity variables. A well-known computational algorithm BVPh2 has been utilized for the solution of the nonlinear system of ODEs. The consequence of innumerable physical parameters on flow field, thermal distribution, and solutal field, such as magnetic field, Lewis number, velocity parameter, Prandtl number, drag force, Nusselt number, and Sherwood number, is plotted via graphs. Finally, numerical consequences are compared with the homotopic solution as a limiting case, and an exceptional agreement is found.

Evaluation of a roadway thermoelectric energy harvester through FE analysis and laboratory tests

ABSTRACT Road surfaces are exposed to solar radiation that generates thermal gradients and heat flow in the pavement layers. The heat stored can be harvested providing an untapped source of renewable energy. This paper presents the design, construction, and assessment of an improved thermoelectric energy system prototype for harvesting heat energy from roadway pavements. To accomplish this, various prototype designs were simulated using Finite Element (FE) analysis, followed by design construction and laboratory testing of the most promising prototypes to evaluate their power harvesting capabilities. The main design components of these prototypes are a heat collector/transfer plate, thermoelectric generators (TEG), and a cooling module consisting of a heat sink, phase change material (PCM), and an insulation box. The results suggest a direct relationship between thermal gradients and power generation and point out the importance of the cooling module in maintaining the efficiency of the harvester. An optimum harvester design can produce a maximum power output of 30.41 mW over a period of 7 hours of summer sunshine in South Texas. Extrapolating this output for an installation that covers a length of 1 kilometre of a roadway could produce an average of 5.4 kWh/day under the conditions described above.

Suppression characteristics and mechanisms of ABC powder on methane/coal dust compound deflagration

ABC powder was widely used at the places of fire extinguishing and explosion suppression due to its excellent suppression performance. In order to investigate the suppression characteristics and mechanism of ABC powder on methane/coal dust compound deflagration flame. A vertical combustion pipe was built to conduct the deflagration experiment of methane/coal dust/ABC powder. The thermal decomposition of coal dust/ABC powder was studied by simultaneous thermal analyzer. The chemical bonds and surface functional groups of the deflagration residue were characterized, and the suppression mechanism of ABC powder was summarized. The experimental results show that the addition of ABC powder increased the initial temperature of coal dust thermal decomposition, which reduced significantly the thermal decomposition rate, heat release and maximum heat flow. The existence of ABC powder weakened significantly the deflagration characteristics of methane/coal dust. The methane/coal dust deflagration was suppressed effectively under 30% ABC powder. The deflagration reaction can be destroyed by physical effects such as heat absorption, heat insulation, dilution of combustible and oxygen concentration, as well as the chemical action of the intermediate which produced by the thermal decomposition of ABC powder on the adsorption of free radicals which maintain the chain reaction.

Special Section on Nanoscale/Microscale Energy Transport, Conversion and Storage in Electronics Packaging

This Special Section of the ASME Journal of Electronic Packaging (JEP) is dedicated to state-of-the-art advancements made in nanoscale and microscale thermal energy transport across a variety of electronics cooling platforms. This topic has quickly emerged as a central issue in electronics packaging, particulary as device length scales approach the mean free path of heat energy carriers and traditional cooling techniques achieve maximum cooling effectiveness. Further, the nanoscale and microscale regimes present unique challenges to dissipating heat from electronics because the physics of energy transport transitions from those described by continuum mechanics to physics that require insight into the way in which quantized microscopic energy carriers traverse within solids and fluids.The set of papers collected as part of this work span a wide variety of areas and provide the readership of JEP with a sampling of important topics in this field. For example, a comprehensive review paper is included to discuss the impacts of nanoscale thermal transport on the performance of emerging devices, such as those used in neuromorphic computing and state-of-the-art power electronics. The paper also provides readers with an exhaustive accounting of how nanostructuring impacts material thermal properties and heat flow across interfaces, and provides individual perspectives on leading devices from 12 experts across 10 separate institutions. The special section also contains invited papers from research groups led by Dr. Nenad Miljkovic (University of Illinois at Urbana Champaign) and Dr. Ankur Jain (University of Texas at Arlington), which describe the development of modular heat sinks for thermal management and backside infrared thermal imaging of semiconductors, respectively. Finally, two papers are included that: (1) evaluate the structural properties of alumina-based ceramic pastes for electronics operating at high temperatures and (2) interrogate the impact of a microchannel/jet impingement cooling technique on the operating conditions of data center servers.It is my hope that such research becomes commonplace in JEP, particularly as the impacts of nanostructuring become more pronounced with continued device miniaturization. Please enjoy the series of papers presented in this special section, and thank you for choosing to read the ASME Journal of Electronic Packaging.