Thermal Scanning Research Articles

Noninvasive Deterministic Nanostructures Lithography on 2D Transition Metal Dichalcogenides

The coupling of nanostructures with emerging 2D semiconductors is gaining significant interest thanks to the unique features of these hybrids systems, which make them key platforms for next‐generation applications in electronics, optoelectronics, and sensing. Top‐down lithographic approaches uniquely enable the fully deterministic high‐resolution fabrication of nanostructures, but some of them, like electron‐beam lithography and focused ion‐beam lithography, employ energetic particles that may damage 2D materials causing an unwanted loss of functionality. Herein thermal scanning probe lithography is applied for the realization of metallic nanoantennas directly on top of exfoliated 2D MoS2 flakes, showing it can avoid the degradation of this delicate substrate. It is shown that the morphologic and optical features of MoS2 are fully preserved after the lithography.

Improving the process of calcination of petroleum coke in a tubular rotary kiln using thermal imaging scanning of its body

Improving the process of calcination of petroleum coke in a tubular rotary kiln using thermal imaging scanning of its body

In situ Fe-doped thin carbon wires via AC high voltage arc discharge

This study explores the controlled, continuous production of thin carbon rods between graphite electrodes (continued electrode deposits) during an arc discharge of high voltage alternating current with a frequency of 50 Hz in liquid paraffin, along with in situ doping of the resulting material using a suspension of liquid paraffin and iron powder ( <10 μm). The surface morphology of the obtained carbon rod nanomaterials was characterized using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), scanning transmission electron microscopy (STEM) with EDX chemical composition analysis, X-ray microtomography (micro-CT), and atomic force microscopy (AFM). The AFM technique in scanning thermal microscopy (SThM) and conductive probe (CP) modes was employed to determine the temperature and electrical conductivity of the obtained nanostructures. Qualitative analysis was conducted using Raman spectroscopy, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). This simple system for producing thin, stable carbon wires (< 1.2 mm thick) enables efficient and low-cost production and doping of these materials. The high-voltage alternating current (HVAC) arc discharge method for growing controlled, metal-doped electrode deposits presents a new approach to producing inexpensive, porous carbon nanomaterials for various scientific and technological applications.

Using Poly(amidoamine) PAMAM-βCD Dendrimer for Controlled and Prolonged Delivery of Doxorubicin as Alternative System for Cancer Treatment

Background/Objectives: Doxorubicin (Dox) is an anticancer drug used in the treatment of a wide range of solid tumors; however, Dox causes systemic toxicity and irreversible cardiotoxicity. The design of a new nanosystem that allows for the control of Dox loading and delivery results is a powerful tool to control Dox release only in cancer cells. For this reason, supramolecular self-assembly was performed between a poly(amidoamine) (PAMAM) dendrimer decorated with four β-cyclodextrin (βCD) units (PAMAM-βCD) and an adamantane–hydrazone–doxorubicin (Ad-h-Dox) prodrug. Methods: The formation of inclusion complexes (ICs) between the prodrug and all the βCD cavities present on the surface of the PAMAM-βCD dendrimer was followed by 1H-NMR titration and corroborated by 2D NOESY experiments. A full characterization of the supramolecular assembly was performed in the solid state by thermal analysis (DSC/TGA) and scanning electron microscopy (SEM) and in solution by the DOSY NMR technique in D2O. Furthermore, the Dox release profiles from the PAMAM-βCD/Ad-h-Dox assembly at different pH values was studied by comparing the efficiency against a native βCD/Ad-h-Dox IC. Additionally, in vitro cytotoxic activity assays were performed for the nanocarrier alone and the two supramolecular assemblies in different carcinogenic cell lines. Results: The PAMAM-βCD/Ad-h-Dox assembly was adequately characterized, and the cytotoxic activity results demonstrate that the nanocarrier alone and its hydrolysis product are innocuous compared to the PAMAM-βCD/Ad-h-Dox nanocarrier that showed cytotoxicity equivalent to free Dox in the tested cancer cell lines. The in vitro drug release assays for the PAMAM-βCD/Ad-h-Dox system showed an acidic pH-dependent behavior and a prolonged profile of up to more than 72 h. Conclusions: The design of PAMAM-βCD/Ad-h-Dox consists of a new controlled and prolonged Dox release system for potential use in cancer treatment.

Violation of the Wiedemann-Franz Law and Ultralow Thermal Conductivity of Ti3C2Tx MXene.

The high electrical conductivity and good chemical stability of MXenes offer hopes for their use in many applications, such as wearable electronics, energy storage, and electromagnetic interference shielding. While their optical, electronic, and electrochemical properties have been widely studied, information on the thermal properties of MXenes is scarce. In this study, we investigate the heat transport properties of Ti3C2Tx MXene single flakes using scanning thermal microscopy and find exceptionally low anisotropic thermal conductivities within the Ti3C2Tx flakes, leading to an effective thermal conductivity of 0.78 ± 0.21 W m-1 K-1. This observation is in stark contrast to the predictions of the Wiedemann-Franz law, as the estimated Lorenz number is only 0.25 of the classical value. Due to the combination of low thermal conductivity and low emissivity of Ti3C2Tx, the heat loss from it is 2 orders of magnitude smaller than that from common metals. Our study explores the heat transport mechanisms of MXenes and highlights a promising approach for developing thermal insulation, two-dimensional thermoelectric, or infrared stealth materials.

Insights into Chemical Bonding Modes and Heat Transport at the Molecular Level.

Despite the demand for nanoscale thermal management technologies of material surfaces and interfaces using organic molecules, heat transport properties at the single molecular level remain elusive due to the experimental difficulty of measuring temperature at the nanoscopic scale. Here we show how chemical bonding modes can affect the heat transport properties of single molecules. We focused on four molecular systems: benzylthiol linked to another phenyl group by either a triple (compound 1), double (3), or amide (4) bond and a common linear alkanethiol (2), all of which are nearly identical in molecular length. We prepared binary self-assembled monolayers (SAMs) using 1 as a common reference in combination with 2-4 and investigated their relative heat transport properties using scanning thermal microscopy (SThM). Two-dimensional temperature mapping of the binary SAMs showed that C≡C and C=C bonds provide more effective pathways for heat transport compared to C-C bonds. Since the amide molecule has resonance structures with C=N double bond character, we expected that its heat transport properties would be comparable to those of the thiols containing triple or double bonds. However, the heat transport properties of this molecule prevailed over the others, most likely due to the formation of additional heat transport pathways caused by intermolecular hydrogen bonding. These findings may provide important guidelines for the design of organic materials for nanoscale thermal management.

Enhancing preservation: Addressing humidity challenges in Indonesian heritage buildings through advanced detection methods point cloud data

Heritage buildings are valuable assets that represent national cultural identity. Proper building maintenance is a major issue for preservation, as building monitoring aspects and preventive measures are often only taken after physical damage happens. In the context of Indonesian heritage buildings, high levels of humidity which may cause condensation and soil dampness are often overlooked. Early detection methods are urgently required to effectively detect potential risks of condensation. This study aims to investigate condensation risk for heritage building surfaces by calculating thermal properties (i.e., emissivity, albedo) and Blinn–Phong BRDF values through the integration of thermal imaging and 3D scanning techniques. This approach supports architects and conservators in making informed decisions to protect and maintain cultural heritage structures. The study also highlights gaps in current Indonesian regulations regarding moisture presence and condensation risk detection in heritage buildings.

Efficient Phase Step Determination Approach for Four-Quadrant Wind Imaging Interferometer

A four-quadrant wind imaging interferometer is a new generation of wind imaging interferometer with the valuable features of being monolithic, compact, light, and insensitive to temporal variations in the source. Its applications include remote sensing of the wind field of the upper atmosphere and observing important dynamical processes in the mesosphere and lower thermosphere. In this paper, we describe a new phase step determination approach based on the Lissajous figure, which provides an efficient, accurate, and visual method for the characterization and calibration of this type of instrument. Using the data from wavelength or thermal fringe scanning, the phase steps, relative intensities, and instrument visibilities of four quadrants can be retrieved simultaneously. A general model for the four-quadrant wind imaging interferometer is described and the noise sensitivity of this method is analyzed. This approach was successfully implemented with four-quadrant wind imaging interferometer prototypes, and its feasibility was experimentally verified.

Enhanced sinterability and mechanical strength of beta-type tricalcium phosphates ceramics through reaction sintering with hydroxyapatite

Beta-tricalcium phosphate (β-TCP) ceramics were fabricated via reaction sintering at 1100 °C, utilizing various phosphate salts and calcium compounds as raw materials. The sintering characteristics, reaction sintering behavior and mechanical properties of the resulting β-TCP ceramics were investigated. Reaction sintering with a Ca/P molar ratio of 1.50 consistently generated β-TCP. In addition, a notable variance in physical properties was observed contingent on the presence or absence of stoichiometric hydroxyapatite (HAp; Ca10(PO4)6(OH)2) in raw materials. Sintered bodies produced with HAp−β-Ca2P2O7 (β-CPP), HAp− CaHPO4·2H2O (DCPD) and HAp−(NH4)2H(PO4) all exhibited densification and enhanced mechanical strength, correlated with higher bulk densities. In contrast, conventional sintered bodies prepared from β-TCP and reaction sintered bodies prepared using β-CPP−Ca(OH)2 or β-CPP−CaCO3 were not as dense. Comprehensive assessments by thermogravimetry-differential thermal analysis, X-ray diffraction and scanning electron microscope together with the evaluation of shrinkage behavior were used to monitor the sintering of β-TCP with HAp. This process was found to involve thermal decomposition of HAp and crystal transitions leading to the formation and sintering of β-TCP with significant shrinkage. These findings underscore the efficacy of employing HAp as a raw material in reaction sintering. This technique allows the formation of sintered β-TCP bodies exhibiting exceptional sintering characteristics, superior bulk density and high mechanical strength.

Effect of al content on microstructure and corrosion resistance of Zn-Al-Mg alloy

In order to solve the solidification microstructure of Zn-1.7Al-1.1Mg alloy on the surface of steel plate during hot dip plating, the solidification path and microstructure of Zn-1.7Al-1.1Mg alloy were studied by Thermo-Calc thermodynamic software, differential thermal analysis (DSC) and scanning electron microscopy (SEM). The results show that during cooling from melting to room temperature, Zn-1.7Al-1.1Mg alloy begins to precipitate Zn-rich η phase at 386.5 °C, binary eutectic structure consisting of η phase and Mg2Zn11 at 350.0 °C, and ternary eutectic structure consisting of η phase, Al-rich metastable β phase and Mg2Zn11 at 343.4 °C,at 276.7 °C, β phase transforms into stable aluminum-rich α and η phases.

Enhanced lead adsorption by eco-hydroxyapatite derived from marble sludge: Optimization and kinetic study

In this study, eco-hydroxyapatite (e-HAP) was synthesized from marble sludge via a hydrothermal process for utilization as an adsorbent in the removal of Pb2+ ions from wastewater. X-ray powder diffraction (XRD) and thermal field emission scanning electron microscope (FE-SEM) revealed that increasing the Ca/P molar ratio (CPMR) and hydrothermal temperature (HT) increased crystallinity and that the influence of HT was more apparent. An increase in crystallinity, crystal length, and peak intensity was observed following an increase in the CPMR. Adsorption studies show that when the HT was 393 K, the CPMR was 0.67, the initial Pb2+ ion concentration was 100 mg/L, the equilibrium time was 20 min, and the adsorbent dosage was 0.6 g/L. The resulting removal efficiency (99.99 %) and maximum adsorption capacity (166.65 mg/g) are both very high. Adsorption kinetics are well described using a pseudo-second-order kinetic model. This paper presents a facile and economically sustainable approach to the synthesis of e-HAP from marble sludge for use in removing of Pb2+ from wastewater.

Synthesis of copper-doped nanocrystalline tin stannate by thermal decomposition of a precursor

Zinc hydroxostannate ZnSn(OH)6, containing 5 mol.% Cu, was obtained from hydrochloric acid solutions of tin(IV), zinc and copper by adding sodium hydroxide to pH = 8–9. The thermolysis process of the obtained sample and the phase composition of the decomposition products were studied using thermal analysis, X-ray diffraction, and scanning electron microscopy. It was shown that the main stages of dehydration are completed at a temperature of about 350 °C and, as a result of thermolysis, an X-ray amorphous product is formed, from which a solid solution of copper in zinc stannate is obtained at an annealing temperature above 650 °C. At an annealing temperature of 800 °C, a mixture of nanocrystalline tin dioxide SnO2 with a cassiterite structure and copper-doped zinc orthostannate Zn2SnO4 with a spinel structure is formed. The room temperature sensors based on ZnSnO3 and carbon nanofibers as a conductive additive showed high response to NO2 (–6.1% to 2 ppm NO2).

Unlocking the secrets of Neapolitan pizza: A concise review of wood-fired, electric, and gas pizza ovens.

This review explores the Neapolitan pizza baking process in a traditional wood-fired oven, employing visual color analysis and IR thermal scanning to detail heat exchange mechanisms. During cooking, the oven floor temperature in the pizza area decreased proportionally to the pizza's mass, whereas the free area maintained a constant temperature of 439±3°C. An IR thermal camera indicated that the oven dome temperature reached approximately 480°C with a weak flame and 500°C with a strong flame. The pizza's bottom achieved a maximum temperature of 100±9°C, facilitated by the Pizzaiolo's skill in lifting and rotating the pizza for uniform cooking. Top temperatures varied: up to 180°C for white pizza and 84°C and 67°C for tomato and Margherita pizzas, respectively. IRIS electronic eye analysis revealed more browning and blackening on the pizza's top compared to its bottom, with peaks of about 26% and 8% for white pizza, respectively. Rapid baking is pivotal in Neapolitan pizza-making, necessitating precise heat and mass transfer management to influence sensory attributes. European Commission Regulation No. 97/2010 mandates wood-fired ovens for true Neapolitan pizza, but environmental concerns prompted the Associazione Verace Pizza Napoletana to certify gas or electric ovens when wood-fired ovens are impractical. Operating costs vary: liquefied petroleum gas ovens are the costliest, with costs ranging from €5.38 to €6.19/h, whereas natural gas and electric ovens have operating costs between €2.70 and €4.10/h. At €0.15/kg, firewood is the most economical, supporting traditionalist views. However, natural gas and electric ovens present competitive costs under stringent antipollution laws, making them viable alternatives.

A General Method for Calibration of Active Scanning Thermal Probes

Scanning thermal microscopy (SThM) is a scanning probe technique aimed at quantitative characterization of local thermal properties at the length scale down to tens of nanometers. With many probe designs and approaches to interpretation of probe responses, there is a need for a universal framework, which would allow probe calibration and comparison of probe performance. Herein, a calibration framework based on an abstracted, formal, probe model for active SThM probes is developed. The calibration can be accomplished through measurements with two or three calibration samples. Requirements for calibration samples are described with examples of structures of suitable samples identified in published literature. A link to a published experimental work indirectly verifying the proposed procedure is provided. The calibration does not require knowledge of internal probe properties and yields a small and universal set of parameters that can be used to quantify thermal resistance presented to the probe by samples as well as to characterize active‐mode SThM probes of any type and at any measurement frequency. How the probe calibration parameters can be used to guide probe design is illustrated. When the calibration approach can be used directly to measure the thermal conductivity of unknown samples is also analyzed.

Antifouling ultrafiltration membranes based on acrylic fibers waste/nanochitosan for Congo red and crystal violet removal

AbstractIn this study, acrylic fibers waste blended with different ratios of nanochitosan (0.5%, 1%, 2% and 4%, in weight) were converted into antifouling ultrafiltration nanocomposite membranes using a phase separation technique for the remediation of Congo red (CR) and crystal violet (CV) dyes from water. The fabricated nanocomposite membranes were investigated using Fourier Transform Infrared (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The membrane hydrophilicity was estimated using contact angle measurements, which revealed that the 4% loaded nanochitosan had the highest hydrophilicity. Additionally, the water uptake, porosity, water contact angle and water flux of the nanocomposite membranes were assessed. The membrane filtration performances were explored for the removal of CR and CV as anionic and cationic dyes, respectively, at different concentrations and various applied pressures (1 bar to 4 bar). The experimental data revealed a high rejection (R) performance for CR (R≃100%) with a high water flux of about 150 L/(m2·h) to 183 L/(m2·h) for the optimized membrane with 2% nanochitosan at an applied pressure of 4 bar. The rejection for CV showed a variant rejection (70%–99%) at different dye concentrations with fluxes ranging from 93.6 L/(m2·h) to 149.5 L/(m2·h) for the same composite membrane. The composite membrane showed enhanced flux recovery after fouling by bovine serum albumin and was resistant to widespread gram-positive (Staphylococcus aureus) bacteria. Graphical abstract

Assembly and Bilayer Liftoff of Periodic Nanostructures with Sub-20 nm Resolution Using Thermal Scanning Probe Lithography

Assembly and Bilayer Liftoff of Periodic Nanostructures with Sub-20 nm Resolution Using Thermal Scanning Probe Lithography

Geothermal Nano-SiO2 Waste as a Supplementary Cementitious Material for Concrete Exposed at High Critical Temperatures.

The partial replacement effect of Portland cement by geothermal nano-SiO2 waste (GNSW) for sustainable Portland-cement-based concrete was investigated to improve the properties of concrete exposed at high critical temperatures. Portland cement was partially replaced by 20 and 30 wt.% of GNSW. The partial replacement effect on Portland-cement-based concrete subjected to 350, 550, and 750 °C was evaluated by measuring the weight changes, ultrasonic pulse velocity, thermogravimetric and differential thermal analysis, X-ray diffraction, surface inspection, and scanning electron microscopy under residual conditions. The ultrasonic pulse velocity results showed that the GNSW specimens maintained suitable stability after being heated to 350 °C. The SEM analysis revealed a denser microstructure for the 20 wt.% of partial replacement of Portland cement by GNSW specimen compared to the reference concrete when exposed to temperatures up to 400 °C, maintaining stability in its microstructure. The weight losses were higher for the specimens with partial replacements of GNSW than the reference concrete at 550 °C, which can be attributed to the pozzolanic activity presented by the GNSW, which increases the amounts of CSH gel, leading to a much denser cementitious matrix, causing a higher weight loss compared to the reference concrete. GNSW is a viable supplementary cementitious material, enhancing thermal properties up to 400 °C due to its high pozzolanic activity and filler effect while offering environmental benefits by reducing industrial waste.

Autonomous post‐disaster indoor navigation and survivor detection using low‐cost micro aerial vehicles

AbstractThis paper introduces an innovative autonomous survivor detection pipeline tailored for low‐cost micro aerial vehicles (MAVs) operating in post‐disaster indoor environments. This consists of three main components: (1) a novel pipeline for survivor geotagging, which includes autonomous navigation, mapping, and detection of survivors using thermal images; (2) a navigation strategy to ensure complete thermal scanning coverage for survivor detection using low‐cost commercial grade thermal camera; and (3) robust and accurate survivor detection using YOLOv8x and thermal imaging. To demonstrate the effectiveness of the proposed framework, first, the autonomous navigation algorithm is simulated in Robotic Operating System (ROS) and experimentally validated under different layouts. Second, the YOLOv8x algorithm is pretrained and achieves high accuracy. Finally, a real‐world implementation was conducted with partially covered survivors in a simulated post‐disaster environment. The results demonstrated the proposed pipeline can accurately map the layout of the environment and identify all survivors. This study demonstrates that affordable MAVs with basic thermal cameras can be effectively used to geotag survivors to support rescue missions during post‐disaster events.

Exploring of new Poly(Thiourea-Amide) as a prospective bismarck Brown Y dye adsorbent: Synthesis via ultrasound irradiation, isotherms, kinetic, thermodynamic, and DFT studies

In this work, a facial ultrasound technique was employed to synthesize poly (N1-((6-aminopyridin-2-yl)carbamothioyl)-N3-carbamothioylisophthalamide) (PTUA) as a new polymer from a condensation reaction of isophthaloyl diisothiocyanate and 2, 6-diaminopyridine. Different techniques were utilized to identify the chemical structure of the synthesized polymer including FTIR spectra, 1HNMR spectra, thermal gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and field emission scanning electron microscopy (FESEM). The capability of the synthesized polymer to adsorb Bismarck brown Y (BBY) dye from an aqueous solution was analytically evaluated. Several effective parameters on the adsorption process including contact time, pH, dye concentration, adsorbent dose, and temperature were extensively investigated. The adsorption process was found to be completed with a contact time of 45 min. The results indicated that the optimal adsorption pH was 8 with removal efficiency of 85.331 % and the adsorbed amount of BBY dye increased when the temperature was increased. The adsorption isotherms analysis revealed that the Langmuir model with a correlation coefficient (R2 = 0.9982) was the most relevant to describe the adsorption process compared with the Freundlich model (R2 = 0.9863). By applying the Langmuir isotherm, the maximum adsorption capacity was obtained with a value of 132.39 mg/g. The study of adsorption kinetics showed that the adsorption model of BBY dye onto the polymer surface significantly correlated with a pseudo-second-order model. Based on the thermodynamic studies, the calculated ΔG was negative, ΔH was endothermic, and ΔS was positive, verifying the adsorption process is spontaneous. The desorption percentage of BBY dye was calculated with a value of 81.574 % utilizing methanol as an optimal solvent. The density functional theory (DFT) approach was applied to acquire good understanding for the adsorption process.

Nanoscale Heat Transport of Vertically Aligned Carbon Nanotube Bundles for Thermal Management Applications.

Electronic devices continue to shrink in size while increasing in performance, making excess heat dissipation challenging. Traditional thermal interface materials (TIMs) such as thermal grease and pads face limitations in thermal conductivity and stability, particularly as devices scale down. Carbon nanotubes (CNTs) have emerged as promising candidates for TIMs because of their exceptional thermal conductivity and mechanical properties. However, the thermal conductivity of CNT films decreases when integrated into devices due to defects and bundling effects. This study employs a novel cross-sectional approach combining high-vacuum scanning thermal microscopy (SThM) with beam-exit cross-sectional polishing (BEXP) to investigate the nanoscale morphology and thermal properties of vertically aligned CNT bundles at low and room temperatures. Using appropriate thermal transport models, we extracted effective thermal conductivities of the vertically aligned nanotubes and obtained 4 W m-1 K-1 at 200 K and 37 W m-1 K-1 at 300 K. Additionally, non-negligible lateral thermal conductance between CNT bundles suggests more complex heat transfer mechanisms in these structures. These findings provide unique insights into nanoscale thermal transport in CNT bundles, which is crucial for optimizing novel thermal management strategies.