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The rapid development of miniaturized, high-frequency, and highly integrated microelectronic devices has brought about critical issues in electromagnetic compatibility and thermal management. In recent years, there has been significant interest in lightweight polymer-based composites that offer both electromagnetic interference (EMI) shielding and thermal conductivity. One promising approach involves constructing three-dimensional (3D) interconnection networks using functional fillers in the polymer matrix. These networks have been proven effective in enhancing the thermal and electrical conductivity of the composites. This mini-review focuses on the preparation and properties of 3D network-reinforced polymer composites, specifically those incorporating metal, carbon, ceramic, and hybrid networks. By comparing the effects of different filler types and distribution on the composite materials, the advantages of 3D interconnected conductive networks in polymer composites are highlighted. Additionally, this review addresses the challenges faced in the field of multifunctional thermal management and electromagnetic protection materials and provides insights into future development trends and application prospects of 3D structured composites. [ABSTRACT FROM AUTHOR]

Contemporary applications require protection against overheating and electromagnetic radiation interference, preferably with reduced mass and enhanced basic performance, such as flammability or chemical or UV resistance and often also low or non‐electrically conductive. Materials exhibiting all these functions can be designed, but there is usually not just one but several different materials with advanced processing requirements; therefore, a simple manufacturing method providing percolation path formation involving powder mixing and hot pressing of providing excellent flexibility terpolymer comprising tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride monomeric units (THV)‐based nanocomposites is presented here. The addition of the graphene nanoplatelets (GNPs) and multiwalled carbon nanotubes (MWCNTs) significantly improves the EMI shielding effectiveness, up to SETOT = 23 dB for the GNP filler, SETOT = 17 dB for the MWCNT/GNP filler per 1 mm samples thickness and enhances almost 900% the thermal conductivity to almost 2 W/mK per GNP filler. Besides this improvement, the electrical conductivity remains at a low level, not surpassing 1.5 S/cm, which is, as mentioned above, beneficial in many applications, especially thermal management. Moreover, the proposed material is an excellent alternative to flexible foam or sponges. Highlights: Structural, electrical, EMI shielding, and thermal properties of flexible THV/GNP, THV/MWCNT, and THV/MWCNT/GNP nanocomposites are shown here.The oriented, long as over 1 mm filler paths are observed.The GNP filler provides the best thermal conductivity enhancement of over 800% compared to bare polymer.The EMI shielding effectiveness is dominated by absorption for all THV‐based nanocomposites.The electrical conductivity follows the power law, reaching σ = 1.49 S/cm for GNP‐filled nanocomposites. [ABSTRACT FROM AUTHOR]

This article employed numerical methods to investigate the aerodynamic, thermal, and infrared characteristics of last-stage turbine swirl on a two-dimensional convergent divergent (2D-CD) exhaust system with an afterburner under varying bypass ratios. The research results indicate that the swirl diminishes the thrust coefficient and flow coefficient of the 2D-CD exhaust system with an afterburner. At a bypass ratio of 0.2, the thrust coefficient and flow coefficient decrease by 0.65% and 1.07%, respectively. When the bypass ratio is relatively small, the swirl flow leads to a decrease in the temperature of the afterburner heat shield. Conversely, when the bypass ratio is relatively large, the opposite occurs. The maximum temperature of the heat shield increases by up to 7.2% (bypass ratio = 0.35), while the average temperature decreases by up to 7.1% (bypass ratio = 0.2). The swirl causes an increase in the temperature of the divergent section heat shield, with the most significant deterioration observed at a bypass ratio of 0.25, resulting in a maximum temperature increase in 12.2%. Swirling flow shortens the length of the jet flow, and as the bypass ratio reduces, this attenuation effect becomes more pronounced. When the bypass ratio is 0.2, the length of the core area decreases by 40.3%, and the infrared intensity of the narrow-side jet flow decreases by 12.5%. Overall, on the XOY detection plane, the maximum decrease in infrared intensity is 11.5%, and the maximum increase is 11.7%. On the XOZ detection plane, the maximum decrease in infrared intensity is 15.9%, and the maximum increase is 5.7%. [ABSTRACT FROM AUTHOR]

The application of compact NMR instruments to hot flowing samples or exothermically reacting mixtures is limited by the temperature sensitivity of permanent magnets. Typically, such temperature effects directly influence the achievable magnetic field homogeneity and hence measurement quality. The internal‐temperature control loop of the magnet and instruments is not designed for such temperature compensation. Passive insulation is restricted by the small dimensions within the magnet borehole. Here, we present a design approach for active heat shielding with the aim of variable temperature control of NMR samples for benchtop NMR instruments using a compressed airstream which is variable in flow and temperature. Based on the system identification and surface temperature measurements through thermography, a model predictive control was set up to minimise any disturbance effect on the permanent magnet from the probe or sample temperature. This methodology will facilitate the application of variable‐temperature shielding and, therefore, extend the application of compact NMR instruments to flowing sample temperatures that differ from the magnet temperature. [ABSTRACT FROM AUTHOR]

The utilization of ceramic aerogels is crucial in spacecraft thermal protection systems that necessitate exceptional high-temperature stability, mechanical robustness, and low thermal conductivity. The primary challenges hindering their implementation encompass inadequate mechanical robustness and high infrared radiation transparency. Herein, a biphasic nanorod encapsulation strategy is proposed to fabricate an Al 2 O 3 -TiO 2 nanorod aerogel (ATNA) with a hierarchical and anisotropic microstructure. The biphasic nanorod structure not only reduces the radiation heat transfer but also enhances the mechanical properties simultaneously. The primary compressive strain was borne by the intersecting Al 2 O 3 nanorods, while the interpenetrated TiO 2 nanorods served to reinforce and withstand partial stress at the joints. The ATNAs obtained exhibit an ultralow thermal conductivity (0.069 W·m−1·K−1 at 1100 °C), exceptional high stiffness (a specific compressive strength of 13.4 kN·m·kg−1), and remarkable thermal stability (1400 °C in air). The robust ATNAs can effectively meet the urgent demand for thermal insulation in high-temperature environments. • A biphasic nanorod encapsulation strategy is proposed to fabricate the Al2O3/ TiO2 ceramic aerogels. • Aerogels possessing the anisotropic and hierarchical structure. • The surface of Al2O3 nanorods is coated with TiO2 nanorods, which effectively absorb and reflect infrared heat radiation. • The derived aerogels exhibit high stiffness, low thermal conductivity and remarkable thermal stability. [ABSTRACT FROM AUTHOR]

Composites with good thermomechanical and UV-shielding properties are essential in fiber-reinforced composites. This paper focuses on composites' ultraviolet (UV) shielding efficiency with added Ce-Zr-Si oxide nanoparticles/epoxy resin. The Ce-Zr oxide nanoparticles were first functionalized with a silicon coupling agent and ethyl silicate to improve their dispersion and surface activity. In this work, we prepared epoxy nanocomposites with the addition of Ce-Zr -Si oxides(1,3,5,7 wt%) and found that the materials had good enhancement of the UV shielding properties of the epoxy resin matrix. Meanwhile, it was used in basalt fiber (BF)/epoxy composites prepared by the hot-pressing method, and surface treatment of basalt fibers was carried out. The results showed that the modified fiber composites could effectively enhance the thermomechanical properties of epoxy resin composites. It is noteworthy that the tensile strength and flexural strength of the hybrid composites reached their peak when 5 wt% Ce-Zr-Si was added, increasing by 13.8% and 33.67% respectively. The modified (BF)/epoxy composites exhibited improved thermal stability compared to pure epoxy resin, with the maximum weight loss temperature of BF-1/EP reaching 349°C. The T(UVA) decreased to 2.41%, while the T(UVB) decreased to 0.053%, and almost all the ultraviolet irradiation was blocked. These results show that our prepared composites have good thermomechanical and UV shielding properties. Highlights • Ce-Zr oxide nanoparticles were functionalized with a silicon coupling agent. • Ce-Zr-Si oxide was added to enhance the ultraviolet shielding efficiency. • Modified BFs were composited to improve thermomechanical properties. [ABSTRACT FROM AUTHOR]

The utilization of hybrid fibers enables the amalgamation of the benefits offered by several types of fibers, while concurrently mitigating their respective limitations. The primary objective of this study is to produce a newly developed hybrid polymer composite that incorporates novel natural fibers, specifically basalt and hemp fiber mat, together with an epoxy matrix and boron carbide (B4C) filler. The objective of this study is to assess the impact of incorporating boron carbide into a polymer composite consisting of basalt and hemp fibers, specifically in relation to its mechanical and thermal shielding properties. The incorporation of boron carbide resulted in enhancements in mechanical properties, specifically an average increase of 8.7% in tensile strength (measured at 191 MPa), flexural strength (measured at 194 MPa), and impact energy (measured at 34 J). Furthermore, the thermal shield analysis demonstrated that the B4C filler possesses the capability to effectively attenuate neutrons, thereby serving as an efficient thermal insulator (with a neutron attenuation coefficient of 4.8 dB/m). The determination of the mode of failure and bonding strength of this hybrid composite can be achieved by conducting a morphological study. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to fabricate a multifunctional electromagnetic interference (EMI) shielding composite fabric with simultaneous high-efficiency photothermal conversion and Joule heating performances. Design/methodology/approach: A multifunctional polypyrrole (PPy) hydrogel/multiwalled carbon nanotube (MWCNT)/cotton EMI shielding composite fabric (hereafter denoted as PHMC) was prepared by loading MWCNT onto tannin-treated cotton fabric, followed by in situ crosslinking-polymerization to synthesize three-dimensional (3D) conductive networked PPy hydrogel on the surface of MWCNT-coated cotton fabric. Findings: Benefiting from the unique interconnected 3D networked conductive structure of PPy hydrogel, the obtained PHMC exhibited a high EMI-shielding effectiveness vale of 48 dB (the absorbing electromagnetic wave accounted for 84%) within a large frequency range (8.2–12.4 GHz). Moreover, the temperature of the laminated fabric reached 54°C within 900 s under 15 V, and it required more than 100 s to return to room temperature (28.7°C). When the light intensity was adjusted to 150 mW/cm2, the PHMC temperature was about 38.2°C after lighting for 900 s, indicating high-efficiency electro-photothermal effect function. Originality/value: This paper provides a novel strategy for designing a type of multifunctional EMI shielding composite fabric with great promise for wearable smart garments, EMI shielding and personal heating applications. [ABSTRACT FROM AUTHOR]

The progressive miniaturization of electronic devices necessitates effective protection against electromagnetic interference and overheating. This study aims to explore the potential of polymer nanocomposites as multifunctional materials to address these challenges in applications related to airborne and space technology. Our investigation focuses on the hypothesis that the incorporation of graphene nanoplatelets (GNPs) into a fluoropolymer matrix (fluorinated ethylene propylene—FEP) will yield a composite material capable of simultaneously providing electromagnetic interference (EMI) shielding and enhanced thermal properties. This research presents initial studies as the foundational step toward designing multifunctional materials for specialized airborne and space technologies applications. The samples, comprising FEP and GNP, were fabricated using a simple powdered masterbatch hot pressing technique, ensuring optimal filler dispersion within the matrix. The dispersion quality was evaluated using Raman mapping and sheet/volume resistivity analyses. Subsequently, adding 25 wt% GNP results in outstanding EMI shielding effectiveness: SETOT ~ 50 dB at 5 GHz for only 1-mm-thick sample and almost 3000% enhancement of thermal conductivity (exceeding 4 Wm−1 K−1), similarly nearly 2000% enhancement of thermal diffusivity (2 mm2 s−1) and an electrical conductivity of over 7 S cm−1 were observed. These results stand out for their remarkable values, especially considering the use of straightforward production methods without further structural improvements or metallic additives. [ABSTRACT FROM AUTHOR]

Conductive polymer composites are highly demanded for practical application in electromagnetic interference shielding and Joule heating owing to their excellent flexibility and adjustable conductivity. Herein, a thin film with a gradient structure, comprising carbon nanotube/castor oil‐based waterborne polyurethane (CNT/WPU), has been fabricated through solution mixing utilizing casting technology. Scanning electron microscopy images confirm that CNTs are enriched at the top of the obtained CNT/WPU film, leading to a low resistance value. Consequently, the resultant gradient CNT/WPU films exhibit shielding effectiveness, specific shielding effectiveness, and an absorption coefficient of 22.8 dB, 1091 dB/cm, and 0.697, respectively, indicating a predominance of absorption in the shielding capacity. The temperature at the surface of the resultant gradient CNT/WPU film reaches ~77°C at a voltage of 20 V. The film with a CNT content of 14.1 wt% exhibits a good stress of 11.7 MPa and a high module of 39.9 MPa. Therefore, the obtained CNT/WPU films can be applied as thin shielding materials or coating. Highlights: Fabricating a gradient CNT/castor oil–based waterborne polyurethane films.Exhibiting shielding effectiveness of 22.8 dB and A‐value of 0.697.Steady‐state temperature of CNT/WPU reaches 77°C at 20 V.Possessing green EMI shielding capability. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of controlled atmospheric re-entry, which has recently gained growing interest from the aerospace scientific and industrial communities for the economic and environmental benefits related to the development of reusable space vehicles. In this context, an original technique based on the incremental formulation of the Model Predictive Control methodology is proposed to tackle the trajectory tracking problem of a small satellite equipped with a deployable heat shield in the de-orbiting phase, focusing on a range of altitude from 300 km to 130 km, i.e., before the atmosphere is dense enough to begin a terminal re-entry phase. The proposed control logic allows following a given pre-determined guidance law, limiting position offsets due to unmodelled disturbances or uncertainties in the knowledge of spacecraft parameters (e.g., drag coefficient). An extensive numerical simulation campaign to assess the control performances in different perturbing conditions has demonstrated its ability to reach a km-error level in the position error at the final altitude of 130 km. • Controlled deorbiting based on aerodynamic drag modulation is addressed. • An Incremental formulation of the MPC controller is proposed for trajectory-tracking. • Performance assessment is carried out in a realistic simulation environment. • The achieved tracking error is kept below 1 km at re-entry interface (130 km). [ABSTRACT FROM AUTHOR]

In this study, (La 0.2 Gd 0.2 Y 0.2 Sm 0.2 Ce 0.2) 2 Zr 2 O 7 ((LGYSC)ZO)), as a new type of thermal barrier coating material, was designed and synthesized. The lattice structure, microstructure, optical, thermophysical, and mechanical properties of the (LGYSC)ZO high-entropy oxide were also investigated. The results showed that a phase-pure pyrochlore-structure (LGYSC)ZO high-entropy oxide, which has a uniform elemental distribution at high temperatures, was successfully synthesized. In addition, the UV–Vis diffuse reflectance spectra results show that (LGYSC)ZO high-entropy oxide has direct and indirect bandgap widths of 3.10eν and 2.51eν, respectively. Infrared (IR) spectra of (LGYSC)ZO high-entropy oxide patterns were measured. The infrared spectra results show that the (LGYSC)ZO high-entropy oxide has better high temperature thermal radiation shielding performance than yttria stabilized zirconia(YSZ). According to the measured result by laser flash method, the thermal conductivity of (LGYSC)ZO high-entropy oxide is at range from 1.18 W m−1 K−1 to 1.37 W m−1 K−1 in the temperature regime from 200 °C to 1000 °C after porosity correction. The coefficient of thermal expansion (CTE) of (LGYSC)ZO high-entropy oxides is at range from about 7.79 × 10−6 k−1 to 11.1 × 10−6 k−1 corresponding temperature from 90 °C to 1000 °C. The mechanical properties of (LGYSC)ZO high-entropy oxides were also investigated, and the hardness and fracture toughness of (LGYSC)ZO high-entropy oxide were 6.61 GPa and 1.27 MPa m1/2, respectively. Therefore, the results indicate that (LGYSC)ZO has excellent properties as a promising thermal barrier coating material. [ABSTRACT FROM AUTHOR]

Microwave and infrared–thermal radiation-compatible shielding fabrics represent an important direction in the development of wearable protective fabrics. Nevertheless, effectively and conveniently integrating compatible shielding functions into fabrics while maintaining breathability and moisture permeability remains a significant challenge. Here, we take hydrophilic PVA-co-PE nanofibrous film-coated PET fabric (NFs/PET) as a flexible substrate and deposit a dielectric/conductive (SiO2/Al) bilayer film via magnetron sputtering. This strategy endows the fabric surface with high electrical conductivity, nanoscale roughness comparable to visible and infrared waves, and a dielectric–metal contact interface possessing localized plasmon resonance and Mie scattering effects. The results demonstrate that the optimized SiO2/Al/NFs/PET composite conductive fabric (referred to as S4-1) possesses favorable X-band electromagnetic interference (EMI) shielding effectiveness (50 dB) as well as excellent long-wave infrared (LWIR) shielding or IR stealth performance (IR emissivity of 0.60). Notably, the S4-1 fabric has a cooling effect of about 12.4 °C for a heat source (80 °C) and an insulating effect of about 17.2 °C for a cold source (−20 °C), showing excellent shielding capability for heat conduction and heat radiations. Moreover, the moisture permeability of the S4-1 fabric is about 300 g/(m2·h), which is better than the requirement concerning moisture permeability for wearable fabrics (≥2500–5000 g/(m2·24 h)), indicating excellent heat and moisture comfort. In short, our fabrics have lightweight, thin, moisture-permeable and excellent shielding performance, which provides novel ideas for the development of wearable multi-band shielding fabrics applied to complex electromagnetic environments. [ABSTRACT FROM AUTHOR]

In this study, (La 0.2 Gd 0.2 Y 0.2 Sm 0.2 Ce 0.2) 2 Zr 2 O 7 ((LGYSC)ZO)), as a new type of thermal barrier coating material, was designed and synthesized. The lattice structure, microstructure, optical, thermophysical, and mechanical properties of the (LGYSC)ZO high-entropy oxide were also investigated. The results showed that a phase-pure pyrochlore-structure (LGYSC)ZO high-entropy oxide, which has a uniform elemental distribution at high temperatures, was successfully synthesized. In addition, the UV–Vis diffuse reflectance spectra results show that (LGYSC)ZO high-entropy oxide has direct and indirect bandgap widths of 3.10eν and 2.51eν, respectively. Infrared (IR) spectra of (LGYSC)ZO high-entropy oxide patterns were measured. The infrared spectra results show that the (LGYSC)ZO high-entropy oxide has better high temperature thermal radiation shielding performance than yttria stabilized zirconia(YSZ). According to the measured result by laser flash method, the thermal conductivity of (LGYSC)ZO high-entropy oxide is at range from 1.18 W m−1 K−1 to 1.37 W m−1 K−1 in the temperature regime from 200 °C to 1000 °C after porosity correction. The coefficient of thermal expansion (CTE) of (LGYSC)ZO high-entropy oxides is at range from about 7.79 × 10−6 k−1 to 11.1 × 10−6 k−1 corresponding temperature from 90 °C to 1000 °C. The mechanical properties of (LGYSC)ZO high-entropy oxides were also investigated, and the hardness and fracture toughness of (LGYSC)ZO high-entropy oxide were 6.61 GPa and 1.27 MPa m1/2, respectively. Therefore, the results indicate that (LGYSC)ZO has excellent properties as a promising thermal barrier coating material. [ABSTRACT FROM AUTHOR]

Topologically interlocking architectures have demonstrated the potential to create durable ceramics with desirable thermo-mechanical properties. However, designing such materials poses challenges due to the intricate design space, rendering traditional modeling approaches ineffective and impractical. This paper presents a novel approach to designing high-performance architectured ceramics by integrating machine learning (ML) techniques and finite element analysis (FEA) data. The design space of interlocked architectured ceramics encompasses tiles with varying angles and sizes. The study considers three configurations 3 × 3 , 5 × 5 , and 7 × 7 arrays of tiles with five sets of interlocking angles (5 ∘ , 10 ∘ , 15 ∘ , 20 ∘ , a n d 25 ∘). By training ML models, specifically convolutional neural networks (CNNs) and multilayer perceptrons (MLPs) using FEA simulation data, we establish correlations between architectural parameters and thermo-mechanical characteristics. A grid comprising all possible designs was generated to predict high-performance architectured ceramics. This grid was then fed into the networks that were trained using results from the FEA simulation. The predicted results for all possible interpolated designs are utilized to determine the optimal structure among the configurations. The goal is to identify the optimal interlocked ceramics that minimize the out-of-plane deformation for thermal shielding and maximize heat absorption for heat sink applications. To validate the performance of the outcomes, FEA simulations were conducted on the best predictions obtained from both the MLP and CNN algorithms. Despite the limited amount of available simulation data, our networks demonstrate effectiveness in predicting the transient thermo-mechanical responses of potential panel designs. Notably, the optimal design predicted by CNN led to ≈ 30 % improvement in edge temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fiber assisted fabrication of thin and self-standing films based on LM. • Continuous electrical/thermal conduction network between LM and MXene. • Superior EMI shielding (78 dB) at tiny thickness (45 μm) • Anisotropic thermal conduction and excellent electro-thermal conversion. • Mechanical reliability and flexibility that can be bended, folded and shaped. The development of thin and flexible films that possess both electromagnetic interference (EMI) shielding and thermal management capabilities has always been an intriguing pursuit, but it is nevertheless a crucial problem to address. Inspired by the deformability of liquid metal (LM) and film forming capacity of MXene, here we present a series of ternary compositing films prepared via cellulose nanofiber (CNF) assisted vacuum filtration technology. Originating from the highly conductive LM/MXene network, the MLMC film presents a maximum EMI shielding effectiness (EMI SE) of 78 dB at a tiny thickness of 45 μm, together with a high specific EMI SE of 3046 dB mm−1. Meanwhile, these compositing films also deliver excellent flexibility and mechanical reliability, showing no obvious decline in EMI shielding performance even after 1000 bending and 500 folding cycles, respectively. Moreover, notable anisotropic thermal conductive property was successfully achieved, allowing for a highly desirable in-plane thermal conductivity of 7.8 W m−1 K−1. This accomplishment also yielded an exceptional electro-thermal conversion capacity, enabling efficient low-voltage (3 V) heating capabilities. These captivating features are expected to greatly drive the widespread adoption of LM-based films in future flexible electronic and wearable technologies. [ABSTRACT FROM AUTHOR]

Asphalt pavements absorb more than 90% of the incident solar radiation, which induces not only high-temperature degradation but also the urban heat island (UHI) effect. In this study, a novel nanoscale non-stoichiometric compound containing tungsten (MxWO3) was used for the first time to prepare thermal shielding coatings to reduce the temperature of pavements and mitigate the UHI effect. Coatings with good shielding characteristics were selected for outdoor thermal insulation tests to evaluate their properties. MxWO3 (M = K, Na, Cs) exhibited significant thermal shielding, especially CsxWO3. Outdoor thermal insulation tests were performed for the CsxWO3 coatings, and it was found that the greater the doping, the more significant the thermal shielding effect. Compared with untreated pavements, the surface-coated pavement exhibited significant cooling at 5 cm and 15 cm depth-wise, which reduced the overall pavement temperature by 1–2 °C, and the coating thickness affected the cooling effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • Asymmetrically optical surfaces integrate radiative cooling and thermal insulation. • Interfaces-engineered nanofabric achieves ∼12.8℃ cooling and ∼7℃ thermal insulation. • Opposite wettability imparts nanofabric with directional sweat transferring capacity. • Synergistic thermal-wetting regulation can be achieved by simple interface inversion. All-weather personal thermal regulation has far been challenged by variable environments especially the regulatory failure caused by highly-dense solar radiation, low environmental radiation and the fluctuated epidermal moisture in different seasons. Herein, from the design of interface selectivity, dual-asymmetrically optical and wetting selective polylactic acid-based (PLA) Janus-type nanofabric is proposed to achieve on-demand radiative cooling and heating as well as sweat transportation. Hollow TiO 2 particles are introduced in PLA nanofabric causing high interface scattering (∼99%) and infrared emission (∼91.2%) as well as surface hydrophobicity (CA > 140°). The strictly optical and wetting selectivity help achieve ∼12.8℃ of net cooling effect under > 1500 W/m2 of solar power and ∼5℃ of cooling advantage higher than cotton fabric and sweat resistance simultaneously. Contrarily, the semi-embedded Ag nanowires (AgNWs) with high conductivity (0.245 Ω/sq) endows the nanofabric with visible water permeability and excellent interface reflection for thermal radiation from body (>65%) thus causing ∼7℃ of thermal shielding. Through simple interface flipping, synergistical cooling-sweat reducing and warming-sweat resisting can be achieved to satisfy the thermal regulation in all weather. Compared with conventional fabrics, multi-functional Janus-type passive personal thermal management nanofabrics would be of great significance to achieve the personal health maintenance and energy sustainability. [ABSTRACT FROM AUTHOR]

For BaO based on steel slag glass system (BaSSG) in chemical composition (50-x)B2O3: 20steel slag: 20Na2O: 10CaO: xBaO (x = 0, 5, 10, 15, 20, 25 wt%) were prepared by melt quenching technique at 1,200 °C and investigated optical, X/γ-rays, fast and thermal neutrons shielding properties. The optical properties were measured and explained on transmission (T%) value. The X/γ-rays shielding properties were experimented with and explained on mass attenuation coefficients (µm) for X-rays which were measured using a high-frequency digital X-rays machine while γ-rays were measured using the narrow beam transmission method. In addition, half value layer (HVL), mean free path (MFP) and transmission factor (TF) values were evaluated and discussed. Also, fast and thermal neutron shielding properties of BaSSG have been evaluated and discussed. The results found that the BaSSG6 glass sample had the highest T% and µm values, while HVL, MFP and TF were the lowest. These results indicated that the BaSSG6 glass sample offers excellent X/γ-rays and fast neutron shielding compared to other samples. Whereas the BaSSG1 glass sample provided superb thermal neutron shielding. These reflected that the BaSSG glass system had the potential to develop transparent and Pb-free shielding material. [ABSTRACT FROM AUTHOR]

Lightweight, flexible, and electrically conductive thin films with high electromagnetic interference (EMI) shielding effectiveness and excellent thermal management capability are ideal for portable and flexible electronic devices. Herein, the asymmetric and multilayered structure Ag-MXene/ANFs composite papers (AMAGM) were fabricated based on Ag-MXene hybrids and aramid nanofibers (ANFs) via a self-reduction and alternating vacuum-assisted filtration process. The resultant AMAGM composite papers exhibit high electrical conductivity of 248,120 S m−1, excellent mechanical properties with tensile strength of 124.21 MPa and fracture strain of 4.98%, superior EMI shielding effectiveness (62 dB), ultra-high EMI SE/t (11,923 dB cm2 g−1) and outstanding EMI SE reliability as high as 96.1% even after 5000 cycles of bending deformation benefiting from the unique structure and the 3D network at a thickness of 34 μm. Asymmetric structures play an important role in regulating reflection and absorption of electromagnetic waves. In addition, the multifunctional nanocomposite papers reveal outstanding thermal management performances such as ultrafast thermal response, high heating temperatures at low operation voltage, and high heating stability. The results indicate that the AMAGM composite papers have excellent potential for high-integration electromagnetic shielding, wearable electronics, artificial intelligence, and high-performance heating devices. [ABSTRACT FROM AUTHOR]

This paper presented a new type of neutron absorption material used in the storage and transportation of spent fuel in nuclear power plants as SiC/Gd 2 O 3 /6061Al composites (SGAC). The optimal component proportion of composites was designed by neutron shielding simulation with MCNP5 software and mechanical property simulation with LAMMPS software. The influence of SiC content on the neutron shielding performance and mechanical properties of the composites was explored by numerical simulation. SGAC with different content of SiC were prepared by SPS technology. The thermal neutron shielding properties, microstructure and mechanical properties for SGAC were analyzed by neutron shielding tests, XRD, typical SEM, TEM, and tensile tests. The neutron shielding test shows that the neutron shielding performance of (0 wt%-25 wt%) SiC/5 wt% Gd 2 O 3 /6061Al SGAC with a thickness of 5 mm all reach above 99.5%. Nanometer Gd 2 O 3 particles and micron SiC particles play intragranular and intergranular reinforcement effects on Al matrix respectively. A new phase Al 4 SiC 4 is generated at the interface of the two phases, facilitating the connection of interfaces. (15 wt% SiC+5 wt% Gd 2 O 3)/6061Al shows superior mechanical properties with the tensile strength of 196 MPa and the elongation of 11%. [ABSTRACT FROM AUTHOR]

To improve heat dissipation capability and enhance mechanical properties, a series of silica aerogel (SA) and modified glass fiber (GF)-filled SBR composites were prepared. It was found that the addition of SA successfully reduced the thermal conductivity of SBR by 35%, owing to the heat shield of the nanoscale porous structure of SA. Moreover, the addition of modified glass fiber (MGF) yielded a significant increase in the tensile and tear strength of SBR/SA composite rubber of 37% and 15%, respectively. This enhancement was more pronounced than the improvement observed with unmodified GF, and was attributed to the improved dispersion of fillers and crosslinking density of the SBR matrix. Rheological analysis revealed that the addition of SA and MGF weakened the ω dependence. This was due to the partial relaxation of immobilized rubber chains and limited relaxation of rubber chains adsorbed on the MGF. Furthermore, the strain amplification effect of MGF was stronger than that of GF, leading to a more pronounced reinforcing effect. [ABSTRACT FROM AUTHOR]

Hierarchical lattice-truss-core sandwich structures have attracted increasing attention by virtue of superior performance in both mechanical properties and lightweight hierarchy topology. However, little work has been reported about the thermo-mechanical responses of such emerging structures. In this research, the effects of high temperature on the out-of-plane compressive properties and failure mechanisms of 3D-printed hierarchical lattice structures are experimentally and numerically investigated. Based on a single-stage pyramidal sandwich structure (P), two kinds of sandwich structures consisting of hierarchical pyramidal truss cores are designed: pyramidal-hollow (PH) and pyramidal-cylinder (PC), all kinds of the structures are integrally fabricated by 3D printing technique of titanium alloy (TC4). The thermo-mechanical coupling and responses during compression are experimentally evaluated from 25 °C to a high temperature of 350 °C. The relevant numerical simulations are carried out by finite element analysis (FEA), which are in well agreement with experimental measurements. It is evident that, compared with the single-stage lattice plate with a same weight, the 3D printed PC-1 type hierarchical configuration has a 131.93% increment in the internal heat-transfer area. Meanwhile, it has a 19.31% and a 26.58% increment in bearing capacity at room and high temperature, respectively. The superior integrated load-bearing and heat shielding efficiency are elucidated through the systematical analysis of the influence of hierarchical design on detrimental failure modes under high temperature: buckling and mixed buckling-plastic fracture of the basic and secondary hierarchy. This work could provide a fundamental knowledge for the future design of lightweight structures with thermo-mechanical superiority in high temperature conditions, such as hypersonic flight vehicles scenarios. [ABSTRACT FROM AUTHOR]

Materials capable of thermal stability electromagnetic interference (EMI) shielding have practical significance in the fields of aerospace. In this paper, a brand-new polymer-derived SiTiOC ceramic nanocomposites with tubular carbon was designed. The titanium atoms were uniformly introduced into the polysiloxane backbone by the transesterification between tetrabutyl titanate and silanol prepolymer, leading to excellent thermal stability properties. By controlling the pyrolysis temperature, a distinct structure of TiC was formed between the amorphous SiTiOC matrix and free carbon phase for enhanced electromagnetic interference shielding performance. More conductive paths were established, and the TiC structure initiated interfacial polarization and space charge polarization, contributing to the improvement of the dielectric loss and relaxation phenomena. Simultaneously, a total electromagnetic interference shielding efficiency of 27.85 dB at the entire X-band was reported for SiTiOC ceramic nanocomposites. A maximum SE T of 38.59 dB was examined at around 12 GHz, suggesting that over 99.99% of the electromagnetic waves were shielded. The SiTiOC ceramic nanocomposites exhibited outstanding prospects in thermal stability electromagnetic interference shielding application in a severe environment. [Display omitted] [ABSTRACT FROM AUTHOR]

With the refinement and miniaturization of integrated electronic devices, the requirements for stable operating temperature and antielectromagnetic interference are increasingly high. However, most of the current materials necessitate to develop the intelligent self‐adaptive regulation in response to external field stimuli to gratify the stipulations of different operating environments. Herein, cuttlefish‐inspired smart liquid metal based‐liquid crystal elastomer (LGN‐LCE) dual‐functional material enabling self‐adaptive electromagnetic wave interference shielding and thermal management is presented. Liquid crystal elastomer matrix endows the LGN‐LCE dynamic self‐morphing properties under thermal activation, which leads to the liquid metal network with tunable thermal/electrical conduction. The thermal conductivity of LGN‐LCE can be increased to 10.3 W m−1 K−1 with the rise of surrounding temperature, while the electrical conductivity of LGN‐LCE can be enhanced to 4.3 × 105 S m−1. Such promoted electrical conductivity helps strengthen electromagnetic interference (EMI) shielding performance of LGN‐LCE, and the minimum EMI shielding effectiveness of LGN‐LCE can be improved from 48 to 62 dB within the X‐band. This work may not only pave a new way to rationally design a self‐adaptive EMI shielding and thermal management systems, but also show good prospects for practical applications, including thermal management materials, EMI materials, flexible electronic materials, smart materials, artificial intelligence systems, biomedical, and aerospace applications. [ABSTRACT FROM AUTHOR]

Space exploration missions rely on ablative heat shields for the thermal protection of spacecraft during atmospheric entry flights. While dedicated research is needed for future missions, the scientific community has limited access to ablative materials typically used in aerospace. In this paper, we report the development of the HEFDiG Ablation-Research Laboratory Experiment Material (HARLEM), a carbon–phenolic ablator designed to supply the need for ablative materials in laboratory experiments. HARLEM is manufactured using polyacrylonitrile-based carbon fiber preforms and a simplified processing route for phenolic impregnation. We characterized the thermal protection performance of HARLEM in arcjet experiments conducted in the plasma wind tunnel PWK1 of the Institute of Space Systems at the University of Stuttgart. We assessed the performance of the new material by measuring surface recession rate and temperature using photogrammetry and thermography setups during the experiments, respectively. Our results show that HARLEM's thermal protection performance is comparable to legacy carbon–phenolic ablators that have been validated in different arcjet facilities or in-flight, as demonstrated by calculations of the effective heat of ablation and scanning electron microscopy of as-produced samples. In-house manufacturing of carbon–phenolic ablators enables the addition of embedded diagnostics to ablators, allowing for the acquisition of data on internal pressure and more sophisticated pyrolysis analysis techniques. [ABSTRACT FROM AUTHOR]

Graphene and its related materials are increasingly applied in fiber‐reinforced polymers to tailor their material properties for high performance composites. Yet, the use of graphene derivatives that underwent a plasma functionalization process is not well understood. This study uses 1.50 wt.% of unfunctionalized (rGO) or plasma‐treated reduced graphene oxide with amine‐functionalities (frGO) in an epoxy matrix to prepare unidirectional pre‐impregnated carbon fibers. The material characteristics of the graphene‐modified carbon fiber‐reinforced polymers (g‐CFRP) are compared to the neat carbon fiber‐reinforced polymer (CFRP). Both g‐CFRP configurations exhibit a higher void content than the neat CFRP. No significant difference between the CFRP and the g‐CFRPs is observed with respect to the Young's modulus, glass transition temperature, storage modulus, specific heat capacity, thermal conductivity at room temperature, and in‐plane electrical conductivity. Yet, a reduction in ultimate tensile strength of up to −13% is noted. In addition, the apparent interlaminar shear strength and transverse electrical conductivity are increased by up to +12% for the rGO‐CFRP and +52% for the frGO‐CFRP. This knowledge will support the selection of additives for fiber‐reinforced polymers for, for example, lightning strike protection in aircrafts, sensory materials, electromagnetic interference shielding or heat transfer elements. [ABSTRACT FROM AUTHOR]

Aerogels were listed among the top ten emerging technologies in chemistry by IUPAC in 2022. Their record‐breaking properties sparked the emergence of a thriving insulation market, but solutions are sought to promote additional applications. A 3D assembly process based on direct ink writing of "aerogel‐in‐aerogel" nanocomposites is presented. The printed polyimide‐silica aerogels are non‐brittle (E = 6.7 MPa) with a super‐insulating thermal conductivity (20.3 mW m−1 K−1) and high thermal stability (T5wt% 447 °C). In addition, they display excellent low‐loss dielectric properties and microwave transmission over all relevant communication bands and can be functionalized for electromagnetic interference (EMI) shielding. The high shape‐fidelity printing, combined with laser‐induced etching of thermally conductive graphene layers, enable precise thermal management for portable electronics or maintain an extreme temperature gradient (−40 to +50°C) across a millimeter‐scale partition. [ABSTRACT FROM AUTHOR]

The economical fabrication of one-dimensional dielectric reflectors using the hybrid sol-gel spin coating process is significant compared to sophisticated chemical and physical vapor deposition techniques. In this work, we opted for alternate layers of TiO2 and SiO2 films to fabricate nearinfrared dielectric reflectors owing to their high refractive index contrast and easy tunability of the reflection window in the desired spectral range. X-ray diffraction (XRD) studies of the monolayer TiO2 and SiO2 confirmed the existence of anatase-TiO2 and amorphous-SiO2 phases, respectively. Spectroscopic ellipsometry investigation of TiO2 and SiO2 films revealed the refractive indices of 2.6 and 1.5, respectively. The field-emission scanning electron microscopy (FESEM) analyses evidenced the fabrication of 2.5 stacks/bilayers of TiO2/SiO2 (TiO2/SiO2)2.5 S. The reflectance measurement demonstrated 100% reflection in the near-infrared region with its center wavelength of 833 nm. In addition, we have examined the water contact angle of various samples using the sessile drop technique, and 2.5 stacks-based reflector showed its lowest contact angle of 29.3°, which suggests its anti-fogging and self-cleaning applications. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) are widely used for protecting components from an aggressive environment and excessive temperatures. However, the top coat can lack thermal compliance and environmental resistance, promoting premature failure. This study provides an approach to design, produce, and evaluate the novel shielded-compliant TBCs to address these challenges. Top coat laser grooving can lower thermal mismatch levels and hinder crack propagation, whereas laser glazing can enhance strength and anti-corrosion performance. Material analysis for the glazed layer revealed large columnar grains alongside a stress-free structure compared to the as-sprayed coating. The digital image correlation (DIC) in-situ heating test showed vertical cracks after glazing already to be effective stress relief features, with the controlled grooves showing the most prominent compliance, as suggested by finite element analysis (FEA). Such a concept may be applied to any coating where increased thermal compliance or environmental protection is needed, making it a highly versatile tool. [Display omitted] • A hybrid thermal barrier coating structure is achieved after grooving and glazing. • Digital image correlation was used to assess the coating at elevated temperatures. • Grooving the top coat with a laser provides a significant reduction in thermal stress. • Columnar grains in the glazed layer can promote additional thermal compliance. • The stress-free structure produced after remelting can benefit the coating lifespan. [ABSTRACT FROM AUTHOR]

Given the electromagnetic interference (EMI) and heat aggregation issue faced by electronic components, an urgent need exists to integrate EMI shielding and thermal conductivity in one material. Herein, a novel lightweight porous Ti 3 SiC 2 ceramic with ordered structural arrangement was fabricated by using budget-friendly raw materials through ice template design and in-situ reaction synthesis. Leveraging the excellent conductivity and thermal conductivity of Ti 3 SiC 2 , a dual-functional advanced material with efficient EMI shielding and thermal management capabilities was obtained. At room temperature, porous Ti 3 SiC 2 ceramics can achieve a shielding effectiveness of 35.44 dB and a thermal conductivity of 12.17 W/mK, with performance that can be tuned by porosity. In further, the porous Ti 3 SiC 2 ceramic can work stably in thermal environments from room temperature to 700 °C or in corrosive environments rich in acid, alkali, and salts due to its excellent high temperature oxidation resistance and corrosion resistance. In view of the dual-functional characteristics and the stability of operation in harsh thermal environments, ordered porous Ti 3 SiC 2 ceramics are promising for modern maritime and aerospace applications. • Oriented lightweight porous Ti 3 SiC 2 ceramics were constructed. • Tunable performances can be accomplished by adjusting the porosity. • Stable electromagnetic interference shielding and thermal conductivity in harsh thermal environments. • This work is valuable for applications in equipments used in complex thermal environments. [ABSTRACT FROM AUTHOR]

The thermal, the electrical conductivity, and electromagnetic shielding properties of low cost high-performance expanded graphite (EG)-filled polybenzoxazine matrix nanocomposites produced by a solution blending and compression molding technique were investigated. At 2.26 vol.% EG, a percolation threshold was detected, at which the electrical conductivity increased by nine orders of magnitude in comparison to the unfilled matrix. The electrical conductivity values increased from 1.35 S.cm−1 to 28.3 S.cm−1 by increasing the EG ratios in the nanocomposites from 7 wt.% and 15 wt.%. In addition, the morphological analysis results revealed good nanofiller dispersion and the formation of 3D-conductive pathways of EG into the polybenzoxazine matrix, which are responsible for the electrical conductivity improvement. Moreover, the electromagnetic interference (EMI) shielding efficiencies, in the X-band, of these nanocomposites have been significantly improved, reaching 57.2 dB at a 15 wt.% EG ratio. Furthermore, the inclusion of EG nanofiller significantly improved the thermal properties of the nanocomposites in terms of first degradation temperatures, char yields, and thermal conductivities. Because of these exceptional properties, these nanocomposites are ideal for high thermal EMI shielding applications. [ABSTRACT FROM AUTHOR]

This article describes the design and configuration of the DEMO Breeding Blanket (BB) feeding pipes inside the upper port. As large BB segments require periodic replacement via the upper vertical ports, the space inside the upper port needs to be maximized. At the same time, the size of the upper port is constrained by the available space in between the toroidal field coils and the required space to integrate a thermal shield between the vacuum vessel (VV) port and the coils. The BB feeding pipes inside the vertical port need to be removed prior to BB maintenance, as they obstruct the removal kinematics. Since they are connected to the BB segments on the top and far from their vertical support on the bottom, the pipes need to be sufficiently flexible to allow for the thermal expansion of the BB segments and the pipes themselves. The optimization and verification of these BB pipes inside the upper port design are critical aspects in the development of DEMO. This article presents the chosen pipe configuration for both BB concepts considered for DEMO (helium- and water-cooled) and their structural verification for some of the most relevant thermal conditions. A 3D model of the pipes forest, both for the Helium-Cooled Pebble Bed (HCPB) and Water-Cooled Lithium Lead (WCLL) concepts, has been developed and integrated inside the DEMO Upper Port (UP), Upper Port Ring Channel, and Upper Port Annex (UPA). A preliminary structural analysis of the pipeline was carried out to check the structural integrity of the pipes, their flexibility against the thermal load, their internal pressure, and the deflection induced by the thermal expansion of the BB segments. The results showed that the secondary stress on the hot leg of the HCPB pipeline was above the limit, suggesting future improvements in its shape to increase the flexibility. Moreover, the WCLL concept did not have a critical point in terms of the secondary stress on the pipeline, since the thicknesses and the diameters of these pipes were smaller than the HCPB ones. [ABSTRACT FROM AUTHOR]

A one-step hybrid bending/diffusion bonding process (HB/DBP) was developed for application to Ti-6Al-4V sheets to effectively improve buy-to-fly (BTF) ratio of aircraft parts, integrating sequential diffusion bonding followed by a bending process. The resulting bonding characteristics of these titanium alloy sheets were analyzed. Microstructural analysis and mechanical lap shear tests were performed to estimate the bonding quality. Additionally, bonding ratio, thickness strain, and shear strength were evaluated in relation to pressure under increasing temperature. When the applied pressure was lower than 0.5 MPa, early failure occurred at the joint of the specimens. However, when high pressure was applied, early failure occurred near the joint. To discuss the phenomenon, time-dependent viscoplastic material properties were characterized, and a numerical simulation analysis was performed. Viscoplastic deformation was observed around the bending area, which caused weakness around the bond under high-pressure conditions. A prototype of a Y-shaped heat shield was manufactured and the buy-to-fly ratio was effectively improved using the newly developed process. This study demonstrates the potential of applying the developed process for producing aircraft parts and the importance of viscoplastic behavior for the analysis of final product reliability. [ABSTRACT FROM AUTHOR]

Fire hazard is a constant risk in everyday life with the use of combustibles such as polymeric materials, wood, and fabrics, to name a few. Halogenated compounds have been widely used as efficient flameretardants, often being applied as coatings or impregnations. With growing environmental concerns and regional bans on the use of halogenated flame-retardant compounds, bio-based alternatives are garnering significant research interest. Naturally occurring materials such as eggshells, DNA, and certain proteins have developed a self-defense mechanism against fire over millions of years of evolution. Cork, a naturally occurring biological tissue in outer bark, is of interest as it is often used as a heat shield and moisture repellent, specifically in spacecraft. A deeper look into the chemical structure of cork indicates the presence of suberin, a bio-polyester group that makes up as much as 40% of its chemical composition. These bio-polyester groups play a key role as a protective barrier between the plant and the surrounding external environment. Thus, the role of suberin in plants could be mimicked for the design of biobased flame-retardant materials. [ABSTRACT FROM AUTHOR]

The paper presents the results of a study of a number of key optical characteristics of some highly porous thermal protection materials based on amorphous SiO2 fibers in the near and mid IR ranges. In the optical part of the statistical simulation model of such materials, based on the rigorous Mie theory, its application requires the introduction of cooperative corrections to the results of interaction with electromagnetic radiation of individual fragments. These corrections are introduced into the model in the form of an additional multiplier (Cs) of the scattering and absorption Mie efficiencies, which was usually used as a model tuning parameter when interpreting the experimental results of thermophysical studies. In this work, using the example of TZM-23M materials (Russia), made of a relatively thick (~9 μm) silica fiber PS-23 (Belarus), for the first time, data were obtained that make it possible to study the Cs parameter as a spectral quantity. The study is based on the results of experimental determination of the spectral hemispherical reflectivity of layers of material of two or more optical thicknesses in the wavelength range 0.83–16.65 μm. These data and Zege's asymptotic formulas were used to estimate the values of the absorption and scattering coefficients. The spectral parameter Cs is determined from the value of the scattering coefficient in the process of solving the inverse optical problem. The data obtained are compared with the results calculated on the basis of classical approximations of the optical constants. The results of this work can be useful for specialists in the field of radiation heat transfer and the interaction of electromagnetic radiation with complex partially transparent media with high spectral albedo scattering values. [ABSTRACT FROM AUTHOR]

The microstructure, surface quality, and thermal shielding properties of the coatings prepared by the methods of magnetron sputtering and electroplating are studied. The results show that the Cr–Ag coating prepared by means of magnetron sputtering is smoother, its porosity and emissivity are lower, and the hardness is higher than that of the coating prepared by means of electroplating. [ABSTRACT FROM AUTHOR]

Semiconductor-grade monocrystalline silicon is the basic material for the integrated circuit industry and its quality determines the performance of chips. The distribution of oxygen content in Czochralski (Cz) silicon crystals has an important impact on the quality of silicon wafers. The oxygen content distribution during crystal growth can be effectively controlled by optimizing the heat shield structure of the furnace, but it is difficult to investigate the intrinsic mechanism through experiments. In this study, effect of the structure of heat shield on the distribution of oxygen content in 200 mm semiconductor-grade Cz monocrystalline silicon was investigated by ANSYS finite element analysis. Single-section and two-section heat shield structures are widely used in commercial furnace, by comparison, the distribution of temperature and flow fields, the temperature gradient at the solid-liquid interface and the radial oxygen content distribution for different stages of body growth (300, 800, 1 000 mm) were analyzed. The simulation results demonstrate that the temperature field uniformity of the single-section heat shield structure is better than that of the two-section heat shield structure, the temperature gradient at the solid-liquid interface in the former is smaller. Also, the low argon flow rate is favorale to the volatilization of SiO gas, and weakening the shear convection of the melt, leading to an inhibition of diffusion movement of oxygen from melt to crystal. Therefore, the radial oxygen content distribution at the solid-liquid interface is more uniform and the oxygen content in the crystal is lower under the condition of the single-section heat shield structure than that of the two-section heat shield structure. [ABSTRACT FROM AUTHOR]

As the operation temperature of next generation gas turbine is targeted to be 1800 °C toward a higher efficiency and lower carbon emission, the near‐infrared (NIR) thermal radiation becomes a major concern for the durability of the metallic turbine blades. Although thermal barrier coatings (TBCs) are applied to provide thermal insulations, they are translucent to the NIR radiation. It is a major challenge for TBCs to achieve optically thick with limited physical thickness (usually < 1 mm) for effectively shielding the NIR radiation damage. Here, an NIR metamaterial is reported, where a Gd2Zr2O7 ceramic matrix is randomly dispersed with microscale Pt (0.53 vol%) nanoparticles with a size of 100–500 nm. Attenuated by the Gd2Zr2O7 matrix, a broadband NIR extinction is achieved through the red‐shifted plasmon resonance frequencies and higher‐order multipole resonances of the Pt nanoparticles. A very high absorption coefficient of ≈3 × 104 m−1, approaching the Rosseland diffusion limit for a typical coating thickness, minimizes the radiative thermal conductivity to ≈10−2 W m−1 K−1 and successfully shields the radiative heat transfer. This work suggests that constructing a conductor/ceramic metamaterial with tunable plasmonics could be a strategy to shield NIR thermal radiation for high temperature applications. [ABSTRACT FROM AUTHOR]

Sugarcane bagasse fiber cellulose nanocrystals (SBFCNC) and microcrystalline cellulose-derived-cellulose nanocrystals (MCC-CNC) were extracted from sugarcane bagasse fiber (SBF; an agricultural waste) and microcrystalline cellulose (MCC), respectively. Both SBFCNC and MCC-CNC were synthesized using sulfuric acid hydrolysis followed by the freeze-drying method. Both MCC-CNC and SBFCNC show stable suspension in water with zeta potential values of – 40.5 mV and – 42.2 mV, respectively. Transmission electron microscopy (TEM) analysis revealed that the SBFCNC has a higher aspect ratio (l/d = 65) compared to the MCC-CNC (l/d = 25). The poly(lactic acid) (PLA) nanocomposites containing of MCC-CNC and SBFCNC was prepared using solvent casting method, and the films are highly amorphous as evidenced from the differential scanning calorimetry (DSC) study. The tensile strength of PLA/SBFCNC-10 is higher than that of PLA/MCC-CNC-10 films. Thermogravimetric analysis (TGA) results showed that the thermal stability of PLA was improved significantly by the incorporation of MCC-CNC and SBFCNC. Poly(lactic acid)/SBFCNC-15 nanocomposites exhibited higher UV shielding properties (i.e., a UV blocking ratio of 0.63–0.66 in the UVA, UVB, and UVC regions) compared to PLA/MCC-CNC-15 nanocomposites (a UV blocking ratio in the range of 0.38–0.54). Sugarcane bagasse fiber cellulose nanocrystal is a potential biofiller that can provide good thermal stability and UV shielding properties for green bionanocomposites, which can give it an opportunity for food packaging applications. [ABSTRACT FROM AUTHOR]

The Stellarator Power Plant Studies Prospective R&D Work Package in the Eurofusion Programme was settled to bring the stellarator engineering to maturity, so that stellarators and particularly the HELIAS (HELical-axis Advanced Stellarator) configuration could be a possible alternative to tokamaks. However, its complex geometry makes designing a Breeding Blanket (BB) that fully satisfies the requirements for such a HELIAS configuration, which is a difficult task. Taking advantage of the acquired experience in BB design for DEMO tokamak, CIEMAT is leading the development of a Dual Coolant Lithium Lead (DCLL) BB for a HELIAS configuration. To answer the specific HELIAS challenges, new and advanced solutions have been proposed, such as the use of fully detached First Wall (FW) based on liquid metal Capillary Porous Systems (CPS). The proposed solutions have been studied in a simplified 1D model that can help to estimate the relative variations in Tritium Breeding Ratio (TBR) and displacement per atom (dpa) to verify their effectiveness in simplifying the BB integration and improving the machine availability while keeping the main BB nuclear functions (i.e., tritium breeding, heat extraction and shielding). This preliminary study demonstrates that the use of FW CPS would drastically reduce the radiation damage received by the blanket by 29% in some of the selected configurations along with a small decrease of 4.9% in TBR. This could even be improved to just a 3.8% TBR reduction by using a graphite reflector. Such an impact on the TBR is considered affordable, and the results presented, although preliminary in essence, have shown the existence of margins for further development of the FW CPS concept for HELIAS, as they have been not found, at least to date, to be significant showstoppers for the use of this technological solution. [ABSTRACT FROM AUTHOR]

We developed and tested two carbon–phenolic-based ablators for future Korean spacecraft heat shield applications. The ablators are developed with two layers: an outer recession layer, fabricated from carbon–phenolic material, and an inner insulating layer, fabricated either from cork or silica–phenolic material. The ablator specimens were tested in a 0.4 MW supersonic arc-jet plasma wind tunnel at heat flux conditions ranging from 6.25 MW/m2 to 9.4 MW/m2, with either specimen being stationary or transient. Stationary tests were conducted for 50 s each as a preliminary investigation, and the transient tests were conducted for ~110 s each to stimulate a spacecraft's atmospheric re-entry heat flux trajectory. During the tests, each specimen's internal temperatures were measured at three locations: 25 mm, 35 mm, and 45 mm from the specimen stagnation point. During the stationary tests, a two-color pyrometer was used to measure specimen stagnation-point temperatures. During the preliminary stationary tests, the silica–phenolic-insulated specimen's reaction was normal compared to the cork-insulated specimen; hence, only the silica–phenolic-insulated specimens were further subjected to the transient tests. During the transient tests, the silica–phenolic-insulated specimens were stable, and the internal temperatures were lower than 450 K (~180 °C), achieving the main objective of this study. [ABSTRACT FROM AUTHOR]

Graphene's highly conjugated network makes processing difficult, limiting its functionality. Graphene oxide (GO) is a popular graphene derivative that allows for water-based processing, while retaining many of graphene's desirable barrier properties. Polyethylenimine (PEI) and GO were alternately deposited via layer-by-layer assembly, thickened with tris(hydroxymethyl) aminomethane (tris), onto polystyrene, and subsequently reduced (rGO) to evaluate the gas barrier and fire protection of the resultant coating. An eight bilayer PEI + tris/rGO coating has an oxygen transmission rate of 2.88 cm3 m−2 day−1 atm−1, which is a 400 × reduction compared to uncoated polystyrene. This 5 μm coating also imparts self-extinguishing behavior following direct flame exposure. This multifunctional film is the first highly aligned graphene oxide nanoplatelet coating to incorporate an amine salt to yield micron-thick films that are suitable for both gas barrier and heat shielding applications. [ABSTRACT FROM AUTHOR]

Applying polyvinyl alcohol(PVA)polymer and cesium tungstate(Cs0.3WO3)powder as the main components, a functional film with near-infrared light shielding performance is prepared by the dissolution-evaporation method. This kind of film can effectively reduce light-to-heat conversion and heat accumulation by shielding the near-infrared light with thermal effect, and consequently achieve the effect of passive cooling. While the weight content of Cs0.3WO3 ranges from 0% to 10%, the effect of Cs0.3WO3 content on the near-infrared shielding performance, as well as cooling performance, of the prepared PVA/Cs0.3WO3 composite film was studied. Cs0.3WO3 can effectively improve the NIR shielding property. With the application of 5% Cs0.3WO3, the transmittance of PVA film in the ultraviolet, visible and near-infrared bands decreases to the value of 12.4%, 30.5% and 19.2% respectively, and the corresponding transmittance in the whole sunlight region is 23.7%, showing good light transmittance performance and near-infrared shielding character. After irradiating infrared light for 60 minutes, the cooling effect of PVA film is 13.1 ℃, showing better passive cooling characteristic. With regard to Cs0.3WO3, a good application prospect is desired in the field of energy saving. [ABSTRACT FROM AUTHOR]

Recently, wood‐based composites have absorbed widespread concern in the field of electromagnetic interference (EMI) shielding due to their sustainability and inherent layered porous structure. The channel structure of wood is often used to load highly conductive materials to improve the EMI shielding performance of wood‐based composites. However, there is little research on how to use pure wood to prepare ultrathin EMI shielding materials. Herein, ultrathin veneer is obtained by cutting wood in parallel to the annual rings. Then, carbonized wood film (CWF) is prepared by a simple two‐step compressing and carbonization. The specific EMI shielding effectiveness (SSE/t) of CWF‐1200 with an ultrathin thickness (140 µm) and high electrical conductivity (58 S cm−1) can reach 9861.41 dB cm2 g−1, which is much higher than other reported wood‐based materials. In addition, the zeolitie imidazolate framework‐8 (ZIF‐8) nanocrystals are grown in situ on the surface of the CWF to obtain CWF/ZIF‐8. CWF/ZIF‐8 exhibits an EMI shielding effectiveness (SE) of up to 46 dB and an ultrahigh SSE/t value of 11 330.04 dB cm2 g−1 in X band. In addition, the ultrathin CWF also shows an excellent Joule heating effect. Therefore, the development of ultrathin wood‐based film provides a research basis for wood biomass to replace traditional non‐renewable and expensive electromagnetic (EM) shielding materials. [ABSTRACT FROM AUTHOR]

A series of Zn 1-x Mn x O (0.001 ≤ x ≤ 0.009) inorganic yellow pigments were prepared by a high-temperature solid-phase method using ZnO and MnO as raw materials. Powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric differential scanning calorimetry (TG-DSC) and so on were applied to test and analyze the designed pigments. The Zn 1-x Mn x O pigments do not contain rare earth elements. The raw materials required for the production of the pigment are readily available and the cost of raw materials is low. The pigment has a high near-infrared (NIR) solar reflectance of 71.87%–84.02%. The pigment can improve the NIR reflectance of the glaze. The box simulation experiment revealed that the Zn 0.995 Mn 0.005 O pigment has better thermal shielding performance than the commercial iron yellow pigment. Additionally, the pigment also has good chemical stability. Therefore, Zn 1-x Mn x O pigments have potential as cold pigments and can be applied to architectural coatings to achieve energy saving effects. [ABSTRACT FROM AUTHOR]