Thermal Features Research Articles

A computational analysis on two phase Eyring-Powell (non-Newtonian) dust particles flow for heat and mass transfer phenomenon with variable thermal features

In this instigation, the heat and mass transfer pattern on Eyring-Powell nanofluid with suspension of dust particles is focused. For heat transfer phenomenon, the Eyring-Powell nanofluid capturing the variable thermal conductivity. Furthermore, the variable and mass diffusivity assumptions are entertained for summarizing the observations chemical reaction phenomenon. The flow is endorsed to magnetic force impact. The additional impact of Brownian motion and thermophoresis consequences have been adopted. The numerical computations with shooting technique are performed. The physical aspects of parameters have been observed graphically. Based on depicted observations, it is examined that the fluid velocity reduces due to interaction velocity parameter which reverse trend is noted for dust particles velocity. The temperature profile for dusty fluid particles enhanced due to interaction parameter for temperature. Furthermore, the concentration profile reduces due to concentration interaction parameter. Current results present applications in solar energy, thermal processes, heat transform devices cooling systems, plasma, manufacturing processes, energy systems, etc.

Investigation of the Magnetic Features of the Fullerene-Dimer-Like Nanostructure (C 60)2: A Monte Carlo Study

The current investigation employs Monte Carlo simulations to explore the magnetic features of a Fullerene-dimer-like nanostructure (C 60)2 characterized by the spin σ−1. It explores how the coupling interaction J σ , the biquadratic parameter K, the external magnetic H and the crystal D fields influence the thermal and magnetic features of the nanostructure, particularly the blocking temperature (T B ). The results also highlight the dependence of hysteresis cycles and the coercive magnetic field Hc on the values of J σ , K, and D, with significant variations at lower temperatures. The findings indicate the distinctive magnetic behavior of the Fullerene-dimer-like nanostructure (C 60)2 potentially useful in various technological applications.

Agricultural by-product filled poly(lactic acid) biocomposites with enhanced biodegradability: The effect of flax seed meal and rapeseed straw

The purpose of this research was to develop “green” materials by combining poly(lactic acid) (PLA) with two agricultural by-products, namely flax seed meal (FSM) and rapeseed straw (RSS). The natural fillers (0–20 wt.%) were mixed with PLA through extrusion and then injection molded into specimens. The samples were analyzed for their thermal, morphological, mechanical, and physical features and biodegradability. Thermal properties and crystallinity were analyzed using Differential Scanning Calorimetry (DSC), while the morphology was investigated by Scanning Electron Microscopy (SEM). Mechanical properties were characterized through tensile, flexural, and impact measurements, while surface hardness was evaluated by Shore D tests. Water absorption and biodegradability of the samples were also examined. DSC measurements revealed a nucleating effect of both bio-fillers. Based on the tensile tests, major improvement in stiffness was found with the biocomposites having up to ∼16 % higher Young's modulus than neat PLA (2.5 GPa). It came, however, at the cost of tensile strength, which decreased from 56 to 51 MPa even in the presence of the lowest amount (2.5 wt.%) of FSM. Loss in strength was due to the limited adhesion between the components, as also supported by SEM images. The hardness slightly (1–2 %) improved in the presence of even 2.5 wt.% bio-filler and it remained at that level at higher filler loading as well. Laboratory-scale composting revealed that both fillers facilitated biodegradation with FSM being superior. In the presence of 10–20 wt.% FSM, the rate of decomposition was found to be twice as fast compared to neat PLA.

Entropy production on mixed convection stagnation point flow of nonlinear radiative fourth-grade hybrid nanofluid through a stretchable Riga surface

The purpose of the current study is to inspect entropy generation, mixed convective stagnation point flow, and thermal transfer features of nonlinear radiative fourth-grade hybrid nanofluid (NF) confined by a convectively heated Riga surface. The heat transport is examined with the existence of two disparate heat source modulations, variable thermal conductivity, and viscous dissipation. The original flow equations are first transmuted using appropriate transformations into non-dimensional ordinary differential equations, which are then solved via an overlapping grid-based spectral collocation scheme. The upshots of various pertinent parameters on velocity, temperature, entropy generation, and valuable engineering quantities are deliberated. Pivotal results obtained reveal that speedily flow of fluid and skin friction can be accelerated by strong magnetic force, rising mixed convection, and material parameters. Also, convective boundary conditions, along with nonlinear radiation and fluctuating thermal conductivity, are recommended for boosting fluid temperature, rates of entropy generation and heat transport. Thermal mechanism in hybrid NF is dominant over simple NF, which implies that performance of hybrid NF is better than that of simple NF. The outcomes of this study can be useful in enriching thermal performance of the working fluid, assisting in diagnosing causes of incompetency in thermal systems, and discovering suitable means of minimizing entropy generation with the intention of mitigating the loss of useful and scarce energy resources.

Anomalous thermal transport and high thermoelectric performance of Cu-based vanadate CuVO3

Thermoelectric (TE) conversion technology, capable of transforming heat into electricity, is critical for sustainable energy solutions. Many promising TE materials contain rare or toxic elements, so the development of cost-effective and eco-friendly high-performance TE materials is highly urgent. Herein, we explore the thermal transport and TE properties of transition metal vanadate CuVO3 by using first-principles calculation. On the basis of the unified theory of heat conduction, we uncover the hierarchical thermal transport feature in CuVO3, where wave-like tunneling makes a significant contribution to the lattice thermal conductivity (κl) and results in the anomalously weak temperature dependence of κl. This is primarily attributable to the complex phononic band structure caused by the heterogeneity of Cu–O and V–O bonds. Simultaneously, we report a high power factor of 5.45 mW·K−2·m−1 realized in hole-doped CuVO3, which arises from a high electrical conductivity and a large Seebeck coefficient enabled by the multiple valleys and large electronic density of states near the valence band edge. Impressively, the low κl and the high power factor make p-typed CuVO3 have ZT of up to 1.39, with the excellent average ZT above 1.0 from 300 to 600 K, which is superior to most reported Cu-based TE materials. Our findings suggest that the CuVO3 compound is a promising candidate for energy conversion applications in innovative TE devices.

Coupled machine-learning approach and thermoelasticity for analyzing thermal stability of the nanocomposite sandwich system

To offer actionable strategies for mitigating the negative impacts of thermal shock loading and enhancing structural design, this study emphasizes the analysis of the transient coupled thermo-elastic behavior of a sandwich cylindrical panel. This panel is subjected to thermal and heat-flux shocks and features face-layers reinforced by functionally graded graphene platelets (FG-GPLRC) alongside a polymeric core. Leveraging compatibility conditions, a three-layered sandwich structure model is developed. Ensuring calculation precision, the governing equations are formulated based on the comprehensive three-dimensional elasticity theory. A numerical approach is adopted for the analytical solution, targeting the response of both fully simple and clamped-supported setups. The Dubner and Abate method aids in inverting the Laplace transform to ascertain the system’s time evolution. In a subsequent section, the derived results are integrated into a novel machine learning algorithm, the Forest Regression for LAyer-wise Structures (FRAS), to anticipate deflection and stress within the layers. The machine learning outcomes align reasonably well with the multi-layered nature of the structure and diverse regression across layers. This suggests that, for swift preliminary insights in engineering applications, machine learning techniques might be a more efficient alternative to traditional numerical computations.

Sub-structures and phase transitions of bi-tilted smectic CG in dimer liquid crystals induced by amide functionalised graphene oxide

ABSTRACT A unique ferroelectric smectic CG phase, in its bi-tilting configurations induced by admixture of the dimeric liquid crystal (LC) 7OBA, serving as an matrix and amide functionalised graphene oxide (AmGO) was presented. Thus, an electrooptically tunable functionalised nanocomposite, indicating bi-tilting state, displayed by two sub-structures, CGcl (clinic) and CGln (leaning) was created. Using both microtextural and DSC analysis, we studied the thermal and structural features of the functionalised nanocomposite. By endothermal peak asymmetry analysis, we found an intermediate between CGcl and CGln state. An enhanced degrees of freedom of the LC director was indicated, allowing an increase of the corresponding micropolarisation LC textures able to create surface memorisation and reach information, respectively.

Enhanced Color‐Preserving Radiative Coolers for Versatile Architectural Applications

AbstractGlobal climate crises are the most significant challenges to be solved these days. As one of the technological endeavors to tackle the issue, radiative cooling is amongst the most attractive approaches for sustainable heat energy regulation, which involves maximizing solar heat reflection and thermal heat emission. These green technologies inevitably require architectural applicability, considering that building facades take a large proportion of the heat‐radiating surfaces. For mass‐production suitability and durability, radiative coolers (RCs) fabricated in a fully ceramic context are recently suggested, featuring scalable, thermally insulative, and non‐shrinking advantages. However, the visual effects are also imperative for architectural instances but are seldom accounted for. In this context, this article suggests the enhanced color‐preserving radiative cooling (ECRC) structure for practical architectural applications of glass‐infiltrated ceramic RCs. By simply blending ceramic pigment into the uppermost porous alumina layer, the ECRC structure can maintain the physical, and thermal features of all‐ceramic RC, while exhibiting color by visible reflectance adjustment. ECRCs exhibit an additional cooling performance of up to ≈17.3 °C depending on their color, compared to their conventional counterparts. With additional chromatic features, ECRC can further enhance the availability of radiative cooling technology for practically realizing the energy‐saving structures in real‐world architectural circumstances.

Predicting thermal transport properties in phononic crystals via machine learning

Although anisotropic phononic crystals (PnCs) could be utilized to control the phonon dispersions and thermal transports, rapidly discovering their properties presents a significant challenge due to the enormous consumption of traditional computational methods. In this study, we have developed machine learning techniques to forecast the thermal conductance of anisotropic PnCs (GPnC and GPnC/Gmem) based on the elastic constants, taking conventional inorganic and halide perovskites as examples for their thermoelectric applications. Our findings suggest that predicting GPnC/Gmem is more challenging than predicting GPnC attribute to the complex influence factors and spatial distribution patterns of the former. The GPnC and GPnC/Gmem of the weakest thermal anisotropic materials—all hexagonals are invariants in the (0 0 1) plane, because the velocities in this plane are direction-independent. The GPnC and GPnC/Gmem of the strongest thermal anisotropic material FAPbI3 reaches the minimum and maximum values in [1 1 0] and [1 0 0] directions, respectively. Ultimately, our machine learning models can map the hidden complex nonlinear relationships between target thermal properties and mechanical features to provide valuable insight for accurate and efficient prediction and analysis of the thermal behaviors of PnCs at a mesoscopic level under low temperatures.

Failure precursors recognition method for loading coal and rock using the fracture texture features of infrared thermal images

Early warning of the catastrophic failure of rocks is a challenging rock mechanics problem. This article proposed a failure precursor recognition method based on infrared thermal image texture features for coal and rock. Based on spatiotemporal background noise correction for infrared thermal images, a new thermal image parameter of loading coal and rock, Contrast Texture Feature Values (CTFV), is proposed to extract subtle changes in the thermal image caused by crack evolution based on the Gray Level Co-occurrence Matrix (GLCM). The cumulative Crack Texture Thermal Image (CTTI) is reconstructed using CTFV, which can accurately reflect the spatial evolution process of loading coal and rock cracks. The CTFV remains at 0 in the early stage of loading and gradually increases with stress increase at the unstable crack propagation stage, which can serve as a reference for precursor warning of coal and rock failure. For shale, sandstone, and limestone, the precursor of CTFV at grayscale levels of 7, 8, and 9, can be classified into high failure risk, medium failure risk, and low failure risk, respectively. For coal samples, the CTFV is only applicable for the critical warning of high failure risk when the grayscale level is 7. Then, an adaptive identification method for failure precursors based on the sliding window probability density estimation method is proposed. The research results can enhance the reliability of IR monitoring technology for rock failure and instability early warning and can provide support for the prevention and control of rock engineering and geological disasters.

Evaluation of a novel composite of expanded polystyrene with rGO and SEBS-g-MA.

This study displays the effect of reduced graphene oxide (rGO) nanofiller and polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene-grafted maleic anhydride (SEBS-g-MA) on the optical, thermal, and mechanical features of expanded polystyrene (EPS). First, the thin films of pristine EPS and composites were prepared using solution cast method. The prepared films were subjected to fourier-transform infrared (FTIR), SEM, UV-visible spectrophotometer, thermogravimetric analysis/differential scanning calorimetry, and universal testing machine for structural, morphological, optical, thermal, and mechanical characterizations. Optical study revealed a significant increase in refractive index and absorption of composites than EPS. Indirect band-gap energy of EPS (~4.08 eV) was reduced to ~1.61 eV for rGO composite and ~ 2.23 eV for composite composed of rGO and SEBS-g-MA. Thermal analyses presented improvement in characterization temperatures such as T10, T50, Tp, Tm, and Tg of composites, which ultimately lead to the thermal stability of prepared composites than pristine EPS. Stress-strain curves displayed higher yield strength (46.62 MPa), Young's modulus (96.29 MPa), and strain at break (0.54%) for EPS+rGO composite than pure EPS having stress at break (1.01 MPa), Young's modulus (12.44 MPa), and strain at break (0.08%). Moreover, ductility with relatively higher strain at break (0.61%) and lower Young's modulus (79.32 MPa) and yield strength (32.98 MPa) was noticed in EPS+rGO+SEBS-g-MA composite than EPS+rGO composite film. Morphological analysis revealed a change in globular morphology of EPS and inhomogeneous dispersion of rGO in EPS to homogeneously dispersed rGO in EPS matrix without globules owing to the addition of SEBS-g-MA. The increase in compatibility of EPS and rGO due to SEBS-g-MA was also observed in FTIR spectra. RESEARCH HIGHLIGHTS: Here, the solution casting approach was used to create the composite film of EPS and rGO with globules of various sizes. After adding SEBS-g-MA, the shape altered to globular free films exhibiting homogenous dispersion of rGO in EPS matrix. An optical investigation showed that composite materials had a significantly higher refractive index and absorption than EPS. The optical, thermal, and mechanical investigations suggest that the produced composites may be a great substitute for virgin EPS, allowing for a wider range of applications.

Applications of Nano-biofuel cells for Reiner-Philippoff nanoparticles with higher order slip effects.

Owing to advanced thermal features and stable properties, scientists have presented many novel applications of nanomaterials in the energy sectors, heat control devices, cooling phenomenon and many biomedical applications. The suspension between nanomaterials with microorganisms is important in biotechnology and food sciences. With such motivations, the aim of current research is to examine the bioconvective thermal phenomenon due to Reiner-Philippoff nanofluid under the consideration of multiple slip effects. The assessment of heat transfer is further predicted with temperature dependent thermal conductivity. The radiative phenomenon and chemical reaction is also incorporated. The stretched surface with permeability of porous space is assumed to be source of flow. With defined flow constraints, the mathematical model is developed. For solution methodology, the numerical simulations are worked out via shooting technique. The physical aspects of parameters are discussed. It is claimed that suggested results claim applications in the petroleum sciences, thermal systems, heat transfer devices etc. It has been claimed that the velocity profile increases due to Bingham parameter and Philippoff constant. Lower heat and mass transfer impact is observed due to Philippoff parameter.

Correlation of microstructure with thermal and tensile creep properties of novel Sn-5Sb-0.5Cu alloy reinforced with Co particles for soldering applications

The present research examined how cobalt microalloying additions of 0.25, 0.5, 0.75, and 1 weight percent affected the microstructural properties, thermal features, and tensile creep characteristics of eutectic Sn-5 wt% Sb- 0.5 wt% Cu (SSC) lead-free solder alloy. According to the results, cobalt additions of 0.25, 0.5, and 0.75 wt% did not affect SbSn phase but significantly refined β-Sn grains, facilitating the formation of fine fibers (Cu,Co)6Sn5 together with plate-like CoSn3 phases, and preventing the formation of Cu6Sn5 phases. Furthermore, a large amount of cobalt (1 wt%) addition accumulated in the coarsening of the CoSn3 phase. Additions of 0.25 wt% Co, 0.75 wt% Co, and 1 wt% Co did not affect the melting temperatures, but pasty ranges had been slightly lowered, which may enhance the thermal characteristics. Addition of 0.5 wt% Co had unfavorable effects on both melting point and pasty range. This has significant effects on solder reliability and electronic service performance. In terms of creep behavior, the SSC-0.75 wt% Co specimens displayed the highest creep resistance because of the fine dispersion of intermetallic compounds (IMCs) and extended the creep-rupture life to a level that is 3.0 times greater than the SSC baseline. Lower creep resistance was observed in SSC-0.25 wt% Co specimens, which was mostly due to the smaller volume fraction of the precipitate phases and the absence of the CoSn3 phase. Depending on the determined stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SSC-xCo solders is the dislocation climb controlled by short-circuit pipe diffusion across the whole temperature range that was examined.

Thermal-hydraulic performance of turbulent flows across a heated round tube installed through several perforated twisted tapes

PurposeThe purpose of this study is to advance turbulent thermal convection inside the constant heat-flux round tube inserted by multiple perforated twisted tapes.Design/methodology/approachThe novel design of this study is accomplished by inserting several twisted tapes and drilling some circular perforations near the tape edge (C1, C3, C5: solid tapes; C2, C4, C6: perforated tapes). The turbulence flow appearances and thermal convective features are examined for various Reynolds numbers (8,000–14,000) using the renormalization group (RNG) κ−ε turbulent model and Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm.FindingsThe simulated outcomes reveal that inserting more perforated-twisted tapes into the heated round tube promotes turbulent thermal convection effectively. A swirling flow caused by the twisted tapes to produce the secondary flow jets between two reverse-spin tapes can combine with the main flow passing through the perforations at the outer edge to enhance the vortex flow. The primary factors are the quantity of twisted tapes and with/without perforations, as the perforation ratio remains at 2.5 in this numerical work. Weighing friction along the tube, C6 (four reverse-spin perforated-twisted tapes) brings the uppermost thermal-hydraulic performance of 1.23 under Re = 8,000.Research limitations/implicationsThe constant thermo-hydraulic attributes of liquid water and the steady Newtonian fluid are research limitations for this simulated work.Practical implicationsThe simulated outcomes will avail the inner-pipe design of a heat exchanger inserted by multiple perforated twisted tapes to enhance superior heat transfer.Originality/valueThese twisted tapes form tiny circular perforations along the tape edge to introduce the fluid flow through these bores and combine with the secondary flow induced between two reverse-spin tapes. This scheme enhances the swirling flow, turbulence intensity and fluid mixing to advance thermal convection since larger perforations cannot produce large jet velocity or the position of perforations is too far from the tape edge to generate a separated flow. Consequently, this work contributes a valuable cooling mechanism toward thermal engineering.

POSS and PEG Contained Copolymer for Antibioadhesive Rigid Contact Lenses Materials Application.

Myopia is a global public health issue. Rigid contact lenses (RCLs) are an effective way to correct or control myopia. However, bioadhesion issues remain one of the significant obstacles limiting its clinical application. Although enhancing hydrophilicity through various surface treatments can mitigate this problem, the duration of effectiveness is short-lived and the processing involved is complex and costly. Herein, an antiadhesive RCLs material was designed via 8-armed methacrylate-POSS (8MA-POSS), and poly(ethylene glycol) methacrylate (PEGMA) copolymerization with 3-[tris(trimethylsiloxy)silyl] propyl methacrylate (TRIS). The POSS and PEG segments incorporated P(TRIS-co-PEGMA-co-8MA-POSS) (PTPM) material was obtained and their optical transparency, refractive index, resolution, hardness, surface charge, thermal features, and wettability were tested and optimized. The antibioadhesion activities, including protein, lipid, and bacteria, were evaluated as well. In vitro and in vivo results indicated that the optimized antibioadhesive PTPM materials present good biocompatibility and biosafety. Thus, such POSS and PEG segments containing material were a potential antibioadhesive RCL material option.

Porosity prediction in laser-based powder bed fusion of polyamide 12 using infrared thermography and machine learning

Achieving precise control in laser-based powder bed fusion of polymers is crucial for ensuring the structural integrity of aerospace and automotive components. Closed-loop feedback control systems using process monitoring techniques, such as infrared thermography, have the potential to provide reliable production by controlling the temperature of the melt. However, challenges arise from complex interactions among variables, such as part geometry, scan strategy, and laser parameters, affecting the melted polymer's temperatures and subsequent particle fusion. Thus, the correlation between thermal signals and resulting part density still needs to be clarified. In this work, a machine learning algorithm is trained to predict local porosity or, rather, solidity based on thermal and temporal features extracted from the melt's temperature-time profile. This enables statistical techniques to assess the contribution of the melt's thermal and temporal features in the decision-making process for evaluating porosity, along with the influence of voxel size and configuration. The in-situ process signature is measured using infrared thermography, and the porosity is analyzed by X-ray micro-computed tomography. The 2D thermal data is first converted into voxel information and then stitched with the 3D mircoCT data in a second step. The resulting 3D thermal features and porosity matrices are downsampled and utilized to train a machine learning algorithm (lightGBM). Models with high prediction accuracy are achieved using a small voxel size to avoid over-homogenizing features and by utilizing thermal signals from adjacent voxels to determine porosity in a volume element. The highest predictor for resulting porosity is the peak temperature of the melt during laser exposure. Interlayer effects, such as sufficient reheating of subsurface layers, are the second-highest indicator for dense parts. Furthermore, the model's performance is also affected by intra-layer effects, including the peak temperature of adjacent voxels and the cooling behavior after laser exposure. This research has several implications for industry, as it enables the detection of process defects based on in-situ process monitoring data without post-process material testing. Moreover, identifying thermal signal ranges that lead to the highest porosity can reduce the number of experiments needed for material qualification processes.

Thermodynamic Analysis of Magnetized Carbon Nanotubes (CNTs) Conveying Ethylene Glycol (EG) Based Nanofluid Flow Through Porous Convergent/Divergent Channel in the Existence of Lorentz Force and Solar Radiation

Due to higher thermal features, carbon nanotubes (CNTs) have significant uses in heating frameworks, medical, hyperthermia, industrial cooling, process of cooling in heat exchangers, electronic and pharmaceutical administration systems, heating systems, radiators, electrical, electronic device batteries, and engineering areas. The main concern of present study is to inspect the EG based CNTs nanomaterials flow in a porous divergent/convergent channel with the application of Lorentz force. The Darcy-Forchheimer theory is utilized to investigate the nanofluid motion and thermal features. Mathematical modeling is further developed by considering Joule heating, solar radiation and heat source. Ordinary differential equations (ODEs) are obtained by employing the proper transformations (obtained from symmetry analysis). The numerical computations are executed through NDSolve technique using Mathematica tool. The upshots of distinct significant parameters on different profiles are displayed via numerical data and sketches. The major outcome is that, enhancement in nanoparticles volume fraction and in inertia coefficient escalate the nanofluids motion for both divergent and convergent. Furthermore, drag forces exerted by the channel is more for higher porosity parameter and inertia coefficient. Also heat transfer rate is significantly enhances against radiation and heat source parameter and is more in case of stretching wall than the shrinking one. Overall, the effect of MWCNT is about 3% is more than that of CWCNT.

Comprehensive study of optical, thermal, and gamma-ray shielding properties of B2O3–SiO2–BeO– MgO–La2O3, glasses

The purpose of this work is to study the thermal, optical, structural, and radiation-shielding features of glass system with composition 57B2O3–16SiO2–11BeO- (16-x) MgO-xLa2O3, x = (0≤x≥16). The structural characteristics of glass samples are examined using XRD. This glass's molar volume decreased from 18.21 to 17.46 (cm³/mol), while its density increased from 3.213 to 5.967 g/cm³. Differential thermal analysis data were used to assess the thermal stability (ΔT) for BSLa samples. It was discovered that when the La2O3 amount increased, the glass stability increased. The optical band gap (Eoptdi), (Eoptindi) and Urbach's energy (Eu) were computed using UV absorption spectra. (Eoptdi) decrease from 4.323 to 3.816 eV and (Eoptindi) decrease from 3.413 to 2.95 eV, whereas (Eu) increase from 0.278 to 0.324 as a result of the changes of borosilicate's structured caused by the addition of La2O3. The examined glasses may be utilized for non-linear optical applications, according to the high (n) and low metallization (M) values. The Phy-X tool was utilized to obtain (MAC), (LAC), and (Zeff) of the suggested glasses within the energies 0.015–15 MeV. The BSLa16 sample achieved the highest values of the (MAC), (LAC), and (Zeff). Consequently, BSLa16 is a good option for gamma-ray shielding applications.

Application of co-crystallization method for the production of ammonium perchlorate/ammonium nitrate oxidizer for solid rocket propellants

Efforts in the quest for greener alternatives to ammonium perchlorate (AP) as a solid rocket propellant oxidizer have intensified due to the associated health and environmental concerns. AP exceptional performance in propulsion is accompagnied by its environmental concerns, necessitating the exploration of greener alternatives. Ammonium nitrate (AN) has emerged as a promising substitute, offering cleaner combustion products and cost-effectiveness. AN-based propellants face challenges such as hygroscopicity and structural instability. This study aims to reconcile the latter challenges by employing a co-crystallization process that embodies a synergistic association of AP and AN, culminating in a novel molecule that harmonizes their distinct advantages and mitigates their individual shortcomings. Optimizing the solvent/antisolvent co-crystallization process through a variation of the antisolvent temperature Ta and antisolvent-to-solvent ratio Ra/s allows to assess their impact on the co-crystallization process of AP and AN and to attain the desired and optimal co-crystal formation conditions. Various characterization techniques were applied to gain deep insights into the co-crystal formation mechanism, its thermal behavior, morphological and structural features together with its thermal decomposition kinetics. Maintaining a low Ta and a high Ra/s (Ta = 15 °C, Ra/s = 11) yielded the design of AP/AN that demonstrates typical indications of the cocrystal formation. The AP/AN cocrystal formation elevated the decomposition temperature by about 18 °C compared to the physical mixture. Furthermore, the combination of AP and AN demonstrates a non-negligible decrease in the HTD temperature compared to that of pure AP by about 110 °C. The kinetic study demonstrated a 50 kJ/mol increase in the activation energy of the AP/AN cocrystal compared to that of the physical mixture. The present research addresses the critical gap in the literature by investigating the co-crystallization of AP and AN that not only improves the safety and environmental impact of solid propellants but also enhances their overall performance and stability.

Tunable Anti‐Thermal Quenching Luminescence of Eu3+‐Doped Metal‐Organic Framework and Temperature‐Dependent Photonic Coding

AbstractApplications of luminescence at high temperature such as high‐power lighting, lasing, thermophotovoltaics, and photonic coding, are severely prevented due to the notorious thermal quenching (TQ). Although anti‐TQ luminescence (anti‐TQL) is reported using highly oxygen‐coordinated solid‐state oxide as host in virtue of the rigid skeleton that resists lattice vibration at elevated temperatures, it is meaningful to extend anti‐TQL to other hosts. Herein, taking advantage of the ligand‐metal antenna effect and the negative thermal expansion feature of Eu3+ doped MIL‐68‐In (MIL‐68‐In/xEu), adjustable anti‐TQL is realized for the first time, that is, anti‐TQ, zero‐TQ, and TQ at x = 5%, 10%, and 50%, respectively. Therefore, except for added novel mechanisms, this work has also expanded the hosts available for high‐temperature luminescence and enabled advanced photonic coding in terms of facial synthesis, rich information, and visual changes of emission intensity instead of device‐dependent analogous.