Thermal Characterization Techniques Research Articles

Overview of thermal and analytical characterization techniques for biofuels and its blends

Overview of thermal and analytical characterization techniques for biofuels and its blends

Paracoccus kondratievae produces poly(3-hydroxybutyrate) under elevated temperature conditions.

As part of ongoing efforts to discover novel polyhydroxyalkanoate-producing bacterial species, we embarked on characterizing the thermotolerant species, Paracoccus kondratievae, for biopolymer synthesis. Using traditional chemical and thermal characterization techniques, we found that P. kondratievae accumulates poly(3-hydroxybutyrate) (PHB), reaching up to 46.8% of the cell's dry weight after a 24-h incubation at 42°C. Although P. kondratievae is phylogenetically related to the prototypical polyhydroxyalkanoate producer, Paracoccus denitrificans, we observed significant differences in the PHB production dynamics between these two Paracoccus species. Notably, P. kondratievae can grow and produce PHB at elevated temperatures ranging from 42 to 47°C. Furthermore, P. kondratievae reaches its peak PHB content during the early stationary growth phase, specifically after 24 h of growth in a flask culture. This is then followed by a decline in the later stages of the stationary growth phase. The depolymerization observed in this growth phase is facilitated by the abundant presence of the PhaZ depolymerase enzyme associated with PHB granules. We observed the highest PHB levels when the cells were cultivated in a medium with glycerol as the sole carbon source and a carbon-to-nitrogen ratio of 10. Finally, we found that PHB production is induced as an osmotic stress response, similar to other polyhydroxyalkanoate-producing species.

Structured illumination with infrared imaging for measuring thermal conductivity

With developments in advanced manufacturing and materials by design comes the need for high-throughput thermal characterization and inspection. Towards this end, Structured Illumination with Thermal Imaging (SITI) is an all-optical pump-probe thermal characterization technique recently developed by our group. In the first generation [Zheng et al., Appl. Phys. Rev. 9, 021411 (2022)] SITI uses an LED with a digital micromirror device (DMD) to “structurally illuminate” and heat the sample with dynamic patterns, a visible light camera for thermoreflectance based “thermal imaging” [leveraging a Microsanj MTIR120], and the resultant temperature response was fit with a thermal model to characterize the sample’s thermal properties. This represents a novel approach to dynamic and flexible spatial mapping of thermal properties by virtue of being a non-contact technique and having a simpler scanning means (computer control only) than conventional pump-probe laser methods. SITI also can tolerate rough samples with diffuse reflections. This talk presents the second generation of SITI. The pumping is now based on a lower cost off-the-shelf digital projector. The thermometry is now performed using an infrared (IR) camera, which we find is a more flexible and accessible hardware approach compared to the thermoreflectance microscopy used previously. With these updates the setup can deliver higher heating power and a broader range of frequencies, allowing an extended range of samples that can be studied. We have demonstrated SITI’s ability to measure the thermal conductivity of a microscope glass slide.

Spatially resolved lock-in micro-thermography (SR-LIT): A tensor analysis-enhanced method for anisotropic thermal characterization

While high-throughput (HT) computations have streamlined the discovery of promising new materials, experimental characterization remains challenging and time-consuming. One significant bottleneck is the lack of an HT thermal characterization technique capable of analyzing advanced materials exhibiting varying surface roughness and in-plane anisotropy. To tackle these challenges, we introduce spatially resolved lock-in micro-thermography, an innovative technique enhanced by tensor analysis for optical thermal characterization. Our comprehensive analysis and experimental findings showcase notable advancements: We present a novel tensor-based methodology that surpasses the limitations of vector-based analysis prevalent in existing techniques, significantly enhancing the characterization of arbitrary in-plane anisotropic thermal conductivity tensors. On the instrumental side, we introduce a straightforward camera-based detection system that, when combined with the tensor-based methodology, enables HT thermal measurements. This technique requires minimal sample preparation and enables the determination of the entire in-plane thermal conductivity tensor with a single data acquisition lasting under 40 s, demonstrating a time efficiency over 90 times superior to state-of-the-art HT thermology. Additionally, our method accommodates millimeter-sized samples with poor surface finish, tolerating surface roughness up to 3.5 μm. These features highlight an innovative approach to realizing HT and accurate thermal characterization across various research areas and real-world applications.

Thermal Conductivity of CaSrFe2O6-δ

The thermal conductivity of CaSrFe2O6-δ, an oxygen-deficient perovskite, is a critical parameter for understanding its thermal transport properties and potential applications in energy conversion and electronic devices. In this study, we present an investigation of the thermal conductivity of CaSrFe2O6-δ at room temperature for its thermal insulation property study. Experimental measurement was conducted using a state-of-the-art thermal characterization technique, Thermtest thermal conductivity meter. The thermal conductivity of CaSrFe2O6-δ was found to be 0.574W/m/K, exhibiting a notable thermal insulation property.

Synthesis and characterization of novel hybrid composites using nanofiller-nanofibrous coating for industrial applications

Synthesis and characterization of novel hybrid composites using nanofiller-nanofibrous coating for industrial applications

Toward a practical method for measuring glass transition in polymers with low-frequency Raman spectroscopy

Glass transition temperature is one of the most important characteristics to describe the behavior of polymeric materials. When a material goes through glass transition, conformational entropy increases, which affects the phonon density of states. Amorphous materials invariably display low-frequency Raman features related to the phonon density of states resulting in a broad disorder band below 100 cm−1. This band includes the Boson peak and a shoulder, which is dominated by the van Hove peak, and quasi-elastic Rayleigh scattering also contributes to the signal. The temperature dependence of the ratio of the integrated intensity in proximity of the Boson peak to that of the van Hove peak shows a kink near the glass transition temperature as determined by differential scanning calorimetry. Careful analysis of the Raman spectra confirms that this is related to a change in the phonon density of states at the transition temperature. This makes low-frequency Raman a promising technique for thermal characterization of polymers because not only is this technique chemically agnostic and contactless but also it requires neither intensity calibration nor deconvolution nor chemometric analysis.

Fabrication and thermophysical characterization of microencapsulated stearyl alcohol as thermal energy storage material

Fabrication and thermophysical characterization of microencapsulated stearyl alcohol as thermal energy storage material

Thermal Conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ

CaSrFe0.75Co0.75Mn0.5O6-δ, an oxygen-deficient perovskite, had been reported for its better electrocatalytic properties of oxygen evolution reaction. It is essential to investigate different properties such as the thermal conductivity of such efficient functional materials. The thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ is a critical parameter for understanding its thermal transport properties and potential applications in energy conversion and electronic devices. In this study, the authors present an investigation of the thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ at room temperature for its thermal insulation property study. Experimental measurement was conducted using a state-of-the-art thermal characterization technique, Thermtest thermal conductivity meter. The thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ was found to be 0.724 W/m/K at 25 °C, exhibiting a notable thermal insulation property i.e., low thermal conductivity.

A Review on the Impact of Various Conditions in Natural Fibre Properties and Their Characterization Techniques

Natural fibre’s significance is increasing day by day, and researchers are still looking for new ones to prove that these have better properties than the existing fibres. Few of them have better properties, and others show their presence to the world. Similarly, volume and the utilization number of composite materials with these fibres may also have developed consistently at the same time. These fibres can be man-made or naturally available materials separated by various possible and availability methods. The primary role behind the preference given to fibres is cost and ease of availability. This paper mainly discussed the different natural fibres and their extraction methods, their compositions, the impact of various alkali treatments on fibre properties, and their applications in multiple fields. Apart from this, mechanical and thermal characterization techniques and their working conditions on numerous fibres; the hybridization with natural/natural fibres or natural with glass fibres into different positions, orientations, and their impact on properties had also been discussed. This detailed study conferred the work reported on natural fibres and included synthetic fibres during hybridization. It may have an advantage for many researchers for further research, whether in terms of improving techniques or increasing the utilization scope of these fibres.

The Impact of Zinc Oxide Micro-Powder Filler on the Physical and Mechanical Response of High-Density Polyethylene Composites in Material Extrusion 3D Printing

The scope of this work was to develop novel polymer composites via melt extrusion and 3D printing, incorporating High-Density Polyethylene filled with zinc oxide particles in various wt. percentages. For each case scenario, a filament of approximately 1.75 mm in diameter was fabricated. Samples for tensile and flexural testing were fabricated with 3D printing. They were then evaluated for their mechanical response according to ASTM standards. According to the documented testing data, the filler increases the mechanical strength of pure HDPE at specific filler concentrations. The highest values reported were a 54.6% increase in the flexural strength with HDPE/ZnO 0.5 wt.% and a 53.8% increase in the tensile strength with 10 wt.% ZnO loading in the composite. Scanning Electron Microscopy (SEM), Raman, and thermal characterization techniques were used. The experimental findings were evaluated in other research areas where they were applicable.

Investigating the Thermo-Oxidative Degradation and Operational Limits for Hybrid AlOX–PET Fabrics Created Via Vapor Phase Infiltration (VPI)

In vapor phase infiltration (VPI), vapor phase metalorganic precursors are diffused into polymers and further reacted with water vapor to form hybrid organic-inorganic materials. Hybrid materials created through VPI have shown utility in industrially relevant applications including membranes for chemical separation, photovoltaics, and catalysis. VPI can be conducted at different temperatures, with each processing temperature resulting in different chemical states that alter the properties of the hybrid material. In this project, polyethylene terephthalate (PET) fabrics are infiltrated with a trimethylaluminum (TMA) precursor and co-reacted with water vapor at a range of infiltration temperatures (60-140 ˚C) to create hybrid AlOX - PET fabrics. The purpose of this project is to develop a set of thermal operational limits for these hybrid organic-inorganic materials and translate techniques for thermal characterization from the textile community to the VPI community. Thermo-oxidative degradation for the hybrid fabrics was quantified through changes in degradation temperature and activation energies. Thermogravimetric analysis (TGA) was employed to quantify inorganic loadings (~20 weight percent inorganic), degradation temperatures, and the activation energy for degradation using the Flynn/Wall/Ozawa (FWO) method for decomposition kinetics. Most hybrid fabrics demonstrated lower degradation temperatures than neat PET, except for the fabric infiltrated at 140˚C which had increased degradation temperatures. Activation energies for the first thermal-oxidative degradation event for the 80˚C, 100˚C, and 140˚C fabrics decreased by a range of 62˚C to 84˚C compared to neat PET, while the 120˚C fabric’s activation energy slightly increased by 10˚C. Additionally, a new degradation event occurred for fabrics infiltrated at low temperatures which was explored through FTIR characterization and attributed to structural rearrangements of the inorganic component. Overall, this work demonstrates how VPI process conditions alter both the organic-to-inorganic chemical binding as well as the inorganic cluster structure in these hybrids and how these structural features affect thermophysical operational limits of the material.

Mechanochemical synthesis and cold sintering of mussel shell-derived hydroxyapatite nano-powders for bone tissue regeneration

According to the circular economy principles, processing routes aiming at reducing the natural resources consumption and the energy demand can be addressed as ‘green’. In this framework, mussel shells, a natural feedstock of calcium carbonate, were successfully transformed into nano-crystalline hydroxyapatite by mechanochemical synthesis at room temperature after mixing with a phosphoric acid solution. The as-synthesized powder was then consolidated up to 82 % relative density by cold sintering (600 MPa, 200 °C). The materials were fully investigated by physical, chemical and thermal characterization techniques. Cold-sintered samples were also subjected to biaxial flexural strength test, showing a flexural resistance of 23 MPa. Cell viability assessment revealed that cold sintered hydroxyapatite derived from mussel shells promotes faster adhesion and spreading of human bone marrow-derived mesenchymal stem cells, in comparison to a commercial hydroxyapatite sintered at 1050 °C. Therefore, cold-sintered mussel shells-derived hydroxyapatite can be a promising future candidate scaffold for bone tissue regeneration.

Nanoscale thermal conductivity of Kapton-derived carbonaceous materials

This study exploits the nanoscale resolution of scanning thermal microscopy (SThM) to reveal inhomogeneous nature of thermal properties of carbon-derived materials issued from thermal conversion of the most commonly known polyimide, Kapton®. This information is otherwise inaccessible if conventional thermal characterization techniques are used due to their limited spatial resolution. Kapton films were pyrolyzed in an inert atmosphere to produce carbon-based residues with varying degree of conversion to free sp2 disordered carbon. The thermal conductivity of carbon materials ranges from 0.2 to 2 W m−1 K−1, depending on the temperature of the carbonization process (varied between 500 and 1200 °C). For quantitative measurements of thermal conductivity, the Null Point SThM (NP-SThM) technique is used in order to avoid unwanted effects as the parasitic heat flows through the air and the probe cantilever. It was found that NP SThM data for bulk materials are in excellent agreement with results obtained through more traditional techniques, namely, photo-thermal radiometry, flash laser analysis, and micro-Raman thermometry. This allowed us to use the NP-SThM technique to differentiate structural heterogeneities or imperfections at the surface of the pyrolyzed Kapton on the basis of the measured local thermal conductivity.

An insight into microscopy and analytical techniques for morphological, structural, chemical, and thermal characterization of cellulose.

Cellulose obtained from plants is a bio-polysaccharide and the most abundant organic polymer on earth that has immense household and industrial applications. Hence, the characterization of cellulose is important for determining its appropriate applications. In this article, we review the characterization of cellulose morphology, surface topography using microscopic techniques including optical microscopy, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Other physicochemical characteristics like crystallinity, chemical composition, and thermal properties are studied using techniques including X-ray diffraction, Fourier transform infrared, Raman spectroscopy, nuclear magnetic resonance, differential scanning calorimetry, and thermogravimetric analysis. This review may contribute to the development of using cellulose as a low-cost raw material with anticipated physicochemical properties. HIGHLIGHTS: Morphology and surface topography of cellulose structure is characterized using microscopy techniques including optical microscopy, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. Analytical techniques used for physicochemical characterization of cellulose include X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and thermogravimetric analysis.

Characterization of cellulosic samples obtained from sisal fibers

In this work the reaction conditions of different chemical treatments used for the isolation of nanocellulose were evaluated. This study clarified the effect of different reaction conditions (time or concentration) on the structure and composition of the cellulosic fibers, To achieve this objective, different chemical, thermal and morphological characterization techniques were used after each chemical treatment and the most suitable reaction conditions were selected.

Review of thermal characterization techniques for salt-based phase change materials

Phase change materials (PCM)-based energy storage system is a quite promising technology for the efficient usage of the excess solar energy produced and utilize it at the hour of high demand. The major challenge here is the selection of PCMs for energy storage applications. Inorganic PCMs possess higher thermal conductivity and energy storage capacity when compared to organic PCMs. Thus, inorganic PCMs have a great potential to be used in energy storage systems majorly in medium to high-temperature applications where organic PCMs cannot be used. An accurate and reliable data on the thermophysical properties of the PCMs is essential before its selection and installation of a energy storage system. In this study, various characterization methods based on calorimetry, temperature difference, cooling rate, and cooling curve used to date are described. Methods such as conventionally used differential scanning calorimetry (DSC), T-history method, and computer-aided cooling curve analysis (CACCA) are reviewed and discussed in this study. The two modes of CACCA, Newtonian, and Fourier techniques are explained. The advantages and limitations associated with all these methods are outlined. Inverse heat conduction problem (IHCP)-energy balance method based on CACCA which is devoid of the limitations associated with the conventional characterization methods is discussed. Thermal conductivity is the main characterization parameter of the PCMs and therefore methods to measure thermal conductivity are critically reviewed in this study. Thermal cycling stability is discussed in the context of the review.

Review on Techniques for Thermal Characterization of Graphene and Related 2D Materials.

The discovery of graphene and its analog, such as MoS2, has boosted research. The thermal transport in 2D materials gains much of the interest, especially when graphene has high thermal conductivity. However, the thermal properties of 2D materials obtained from experiments have large discrepancies. For example, the thermal conductivity of single layer suspended graphene obtained by experiments spans over a large range: 1100–5000 W/m·K. Apart from the different graphene quality in experiments, the thermal characterization methods play an important role in the observed large deviation of experimental data. Here we provide a critical review of the widely used thermal characterization techniques: the optothermal Raman technique and the micro-bridge method. The critical issues in the two methods are carefully revised and discussed in great depth. Furthermore, improvements in Raman-based techniques to investigate the energy transport in 2D materials are discussed.

Impact of roughness on heat conduction involving nanocontacts

The impact of surface roughness on conductive heat transfer across nanoscale contacts is investigated by means of scanning thermal microscopy. Silicon surfaces with the out-of-plane rms roughness of ∼0, 0.5, 4, 7, and 11 nm are scanned both under air and vacuum conditions. Three types of resistive SThM probes spanning curvature radii over orders of magnitude are used. A correlation between thermal conductance and adhesion force is highlighted. In comparison with a flat surface, the contact thermal conductance can decrease as much as 90% for a microprobe and by about 50% for probes with a curvature radius lower than 50 nm. The effects of multi-contact and ballistic heat conduction are discussed. Limits of contact techniques for thermal conductivity characterization are also discussed.

EPR-TL correlation, in radiation shielding Ba(10-x)MnxLa30Si60 glasses

• The Ba (10-x) Mn x La 30 Si 60 glasses are capable of radiation shielding. • The microhardness (10.784 ∼ GPa) range, suggest higher rigidity and elastic strength. • The glass with 1.0 mol% of MnO concentration is showing better TL intensities. • The super-exchange dipole-dipole interaction and rhombic distortion with in the glasses lead to electron paramagnetic resonance. • Glasses are EPR-TL correlative upon suitable gamma irradiation. The well-known phenomenon, electron paramagnetic resonance, and thermoluminescence are used to investigate paramagnetically, and thermo-luminescent behavior of the materials to advance magneto-thermo-lumina applications. However, still, there is a necessity to introduce a correlation (or) mechanism in between electron paramagnetic resonance, and thermoluminescence to understand the radiation shielding (or) electromagnetic induction shielding phenomenon within the resource like glasses, ceramics, thin film (or) polymers. In this view, the Ba (10-x) Mn x La 30 Si 60 series of glasses are prepared. The non-crystallinity behavior and glass-forming abilities are verified by X-ray diffraction and differential thermal analysis characterization techniques. The glasses are showing non-homogeneity, de-polymerization, entropic, and de-clustering behavior with increased MnO concentration. The thermal stabilities of the glasses are reported from the DTA studies. Ultrasonic velocities were recorded to evaluate the elastic characteristics of glasses. The radiation shielding studies of glasses suggest the radiation shielding phenomenon purely a function of the MnO concentration. In this view, the results and values of mass attenuation coefficient, radiation protection efficiency, mean free path, and energy absorption build-up factor suggest more glassy thickness is required to attenuate high energy radiation. The electron paramagnetic resonance reports suggest high order of dipole-dipole super exchange interaction and rhombohedral distortion within the glasses. Which also reveals the six-state characteristic trace of the octahedral Mn 2+ ions. Upon 50 kGy, γ-irradiation, the thermoluminescence properties of the glasses are reported. Trap depth parameters are calculated, which reveal the resource developed are thermoluminescent at low activation energies. Moreover, to introduce the detailed correlation between electron paramagnetic resonance, and thermoluminescence phenomenon, we have annealed the glasses under 0 to 300°C temperature and upon the 0 to 50 kGy γ - irradiation dose level. In this view, the results upon the electron paramagnetic resonance and thermoluminescence properties obtained for the glasses are highly correlative.