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In this study, we modeled the multi‐model blending process using random variables and explicitly derived the distribution of the blended forecast error under the assumption of normally distributed errors. Utilizing this error distribution, we regained the scalar version of the Best Linear Unbiased Estimator. Notably, the model yielded negative weights, which contradict traditional assumptions that weights should be positive. To address this, we modified the algorithm to set negative weights to zero and compared the performance with the original algorithm. Our findings indicate that setting negative weights to zero results in a slight improvement in blending performance compared to using negative weights directly. This improvement may be attributed to modeling the actual forecast error as a normally distributed unified parameter and applying a consistent correlation coefficient across the annual data set. Plain Language Summary Multi‐model blending is a widely used technique in operational practices aimed at improving forecast accuracy. Traditionally, methods such as Bayesian Model Averaging, Kalman Filtering (KF), or score‐based weight assignment algorithms are employed for this purpose. However, there has been limited discussion on how the error of the blended forecast compares to the original forecasts involved in the blending process. This paper uses random variables to mathematically model the blending process. The model provides the distribution of the blended forecast error under certain assumptions, specifically that the forecast errors follow a normal distribution. It demonstrates how the blended forecast error changes compared to the pre‐blending error. Based on this distribution, we derived an optimal method for calculating blending weights, which aligns with the scalar form of the Best Linear Unbiased Estimator. Since the algorithm does not impose any restrictions on the positivity or negativity of the weights, we further tested the impact of setting negative weights to zero. The results indicate that under the condition of an imperfect model, setting the calculated negative weights to zero may could slightly improve the accuracy of the algorithm. Key Points This research used random variables to model the widely used weighted average multi‐model blending algorithm accurately Correlation between forecasts is important in explaining the blending performance, for example, why blending have negative effects in some cases Since the algorithm allows negative weights, we tested their impact. Results showed no improvement with negative weights in our model

In this study, PLA-TPU blends with different component ratios were prepared and printed by melt blending and fused deposition modeling (FDM), respectively. The shape memory effect (SME) was investigated considering the effect of loading mode, programming deformation, and temperature for three combinations of PLA50, 70, and 90 wt%. The results of the thermal analysis showed that each compound had two glass transition temperatures in the range of −20 and 67 °C, which return to TPU and PLA, respectively. SEM results confirmed that TPU droplets are observed in the PLA matrix and the printed samples had stretched the TPU phase. In both loading modes, with the increase in PLA concentration, the fixity ratio increased and the highest shape recovery value was obtained in the PLA70 samples, although the values were very close to PLA50. The crystalline segments of PLA, as a net point, play an essential role in restoring the original shape, and by increasing the amount of PLA, stricter limitations are created. In the compression mode, although the programming stress was the highest in the cold-programmed sample, the highest stress was released in the warm-programmed samples. The maximum recovery stress value for PLA70 was 12.85 MPa, which can be effective in reducing the limitations of applications for shape memory polymers. The shape recovery ratio was in the 90.9–96.4% range under compression loading. Also, the cold-programmed samples showed the highest and lowest fixity and recovery ratios. The results of this research show that by changing the composition and programming temperature, the desired properties for different applications can be achieved so that the highest fixity, recovery, and stress recovery were obtained in hot, cold, and warm-programmed samples by manipulating the input energy and temperature. Graphical abstract

Purpose This study experimentally developed and characterised dry-blended Polycaprolactone (PCL)/date palm fibre biodegradable composites for sustainable packaging applications. Date palm fibres are collected from date palm trees as by-products or waste materials. They will be valorised in bio-composite application to promote fibre-based sustainable packaging items over their non-biodegradable synthetic polymer based conventional packaging products. In the dry-blending process, fibre and polymer are mixed with a shear mixer, while, in a melt-blending process, an extruder is used to extrude fibre/polymer blends after applying heating and high shear pressure to melt and mix polymer with fibres. Dry-blending process offers many comparative advantages, such as less equipment, steps, cost, process degradation, energy consumption and hence, lower harmful environmental emissions; while, a proper fibre/polymer mixing is a challenge and it needs to be achieved properly in this process. Therefore, it is important to understand the effects of dry-blending process on manufacturing of PCL/date palm fibre bio-composites for packaging applications, before promoting the dry-blending as a suitable alternative to the melt-blending process. Methods Short chopped fibres were grinded as powders and dry-blended at a ratio of (0 − 10%) (w/w) with PCL polymer using hand and a shear mixer for 30 min, following a compression moulding process to produce bio-composite samples. Tensile, water contact angle, SEM, TGA, DSC and DMA tests and analysis were conducted. The dry-blended PCL/date palm fibre composites’ properties were compared with reported melt-blended samples’ results found in literature. Results Dry-blended samples showed an increase in tensile modulus values (up-to 20%) with fibre inclusion and these values were found close to the melt-blended samples in the literature. Tensile strength and strain values were reduced which could be related to the poor fibre/polymer interface. Fibre addition affected the thermal, thermo-mechanical and crystallisation processes in PCL polymer matrix. Conclusion Dry-blending is capable of producing bio-composites with a very comparable properties to melt-blended counterparts, although a more details study is needed to conduct in future. The results of this study, could be used carefully to design dry-blended PCL/date palm fibre bio-composites for possible packaging applications. The irregular fibre distribution in dry-blended samples could be improved in different ways which should be investigated in future. Graphical Abstract

In the present work, a novel method is exhibited for tuning the surface plasmon resonance (SPR) peaks of silver nanoparticles based on chitosan-Poly(vinyl alcohol) blend polymer nanocomposites. Silver nanoparticles were synthesized by in situ method through the chitosan host polymer. The absence of crystalline peaks of PVA in the blend system indicated the occurrence of miscibility between CS and PVA polymers. The UV–vis spectra of CS:AgNt samples shows SPR bands with weak intensity. Obvious tuning in SPR peaks of silver nanoparticles occurred when different amounts of PVA polymer incorporated to the CS:AgNt system. The appearance of distinguishable crystalline peaks of Ag° nanoparticles at 2θ = 38.6° and 2θ = 44.2° in the blend system reveals the role of polymer blending in the enhancement of SPR peaks of silver nanoparticles. Silver nanoparticles synthesized in this work with enhanced SPR peaks are important in various applications and areas such as optoelectronic devices. The TEM images show dispersed silver nanoparticles. The dielectric constant of PVA is higher than that of chitosan. The result of dielectric constant study validates the Mie model which reveals the fact that the dielectric constant of the surrounding material has a great effect on the SPR peak intensity of nanoparticles.

PurposeSustainable Aviation Fuel (SAF) is crucial for aviation decarbonization, but its current pre-blending process at refineries presents challenges, including fixed blending ratios, higher transportation costs and long lead times. This study explores the potential of an innovative technology that enables on-site SAF blending at airports. By postponing blending to the point of use, this approach offers customization opportunities. However, the precise benefits and trade-offs of this concept remain unclear. The research aims to assess the impact of on-site blending on fuel price, lead time, carbon emissions and supply chain costs.Design/methodology/approachThis empirical study evaluates the effects of SAF postponement using case analyses of Singapore-Seletar and Maastricht airports. The analysis incorporates cost modeling, lead time assessment and carbon impact calculations to quantify the implications of shifting blending downstream to airport sites. Data sources include industry reports, airport-specific logistics information and SAF supply chain parameters. A comparative analysis is conducted to determine optimal airport conditions for SAF postponement, highlighting key enablers and barriers to implementation.FindingsThe results indicate that on-site SAF blending can create competitive advantages by reducing supply chain costs and lowering carbon emissions. The benefits are contingent on airport-specific factors, such as Hydroprocessed Esters and Fatty Acids availability, logistics infrastructure and regulatory conditions. The findings suggest that certain airports, particularly those with strategic locations and favorable cost structures, are better suited for adopting SAF postponement. By shifting production downstream, airports can achieve greater flexibility in SAF blending ratios while minimizing logistical inefficiencies.Originality/valueTo the best of the authors’ knowledge, this study is among the first to empirically examine the feasibility of postponing SAF blending to the airport level. While existing literature focuses on SAF production and distribution, the concept of downstream blending has not been systematically analyzed. The research provides new insights into how mass customization principles can be applied to SAF supply chains, potentially reshaping fuel logistics in the aviation industry. By identifying critical factors for successful implementation, this study contributes to both academic discussions and practical decision-making in sustainable aviation fuel management.

Various parameters of a melt blending processing including the extruders’ type, processing conditions (barrel temperature, screw speed and screw configuration), shear rate, residence time and distribution in relation to the mechanical properties of polymer nanocomposites were qualitatively reviewed. The tensile, flexural and impact strengths and their moduli of the composites were discussed. It was found that the tensile modulus of the extruded nano-sized fillers-reinforced polymers is highly influenced by these fillers’ distribution and their planner orientation in the polymeric matrix. The use of intermeshing co-rotating twin-screw extruders can provide better exfoliated/intercalated nanocomposites' structure with superior mechanical strength when compared to the composites made by the other processing methods. However, it was noticed that the tensile strength of the composite is not substantially affected by changing the melt blending processing parameters.

PBT and PET are subjected to thermal-oxidative degradation and thermomechanical degradation during the process of melt blending, which affect the polymer structure and properties. The effect of feed properties of PET and the addition of modified nanoparticles on blends are a question worthy of discussion. This work describes the melting and thermal stability, the crystallization behavior and non-isothermal crystallization kinetic, the rheological behaviors and mechanical properties of several PBT/PET blends prepared by twin-screw melt extrusion. Results show that the molecular chain of the polyester blends obtained by stable extrusion are not significantly degraded, there is only one obvious melting peak and crystallization peak on the thermal analysis curves, and the melting point is lower than either of the two polyesters. An appropriate amount of SD can effectively reduce the crystallization rate of the PBT material and extend the crystallization time. The rheological behavior of PBT/PET blends is complicated than PET raw materials and SD, as well as the melt processing temperature and shear rate will all affect the rheological behavior of the blends. For example, at low shear rate, polyester blends with SD exhibit strong shear thinning behavior. In general, the SD content affects the rheological property of blends in a way similar to the law of influence on crystallization behavior. When SD content is 0.3 wt%, a polyester product with higher elongation at break than pure PBT can be obtained. This can provide a useful reference for preparing commercialized polyester blend products with good melt processability and elongation by simple blending.

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

In recent years, poly(lactic acid) (PLA) has attracted more and more attention as one of the most promising biobased and biodegradable polymers. However, the inherent brittleness significantly limits its wide application. Here, ternary blends of PLA, poly(ε-caprolactone) (PCL) with various amounts of ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer were fabricated through reactive melt blending in order to improve the toughness of PLA. The effect of different addition amounts of EMA-GMA on the mechanical properties, interfacial compatibility and phase morphology of PLA/PCL blends were studied. The reactions between the epoxy groups of EMA-GMA and carboxyl and hydroxyl end groups of PLA and PCL were investigated thorough a Fourier transform infrared (FT-IR). The miscibility and thermal behavior of the blends were studied through a dynamic mechanical analysis (DMA), differential scanning calorimetric (DSC) and X-ray diffraction (XRD). The phase morphology and impact fracture surface of the blends were also investigated through a scanning electron microscope (SEM). With the addition of 8 phr EMA-GMA, a PLA/PCL (90 wt %:10 wt %)/EMA-GMA ternary blend presenting a suitable multiple stacked phase structure with an optimum interfacial adhesion exhibited an elongation at break of 500.94% and a notched impact strength of 64.31 kJ/m2 with a partial break impact behavior. Finally, the toughening mechanism of the supertough PLA based polymers have been established based on the above analysis.

This study addresses these limitations by preparing PMMA/SiO2-g-PMMA/TPP composites via melt blending and utilizing the synergistic effect between SiO2-g-PMMA and TPP. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the successful synthesis of SiO2-g-PMMA with effective grafting. Fire safety tests revealed that increasing triphenyl phosphate (TPP) content in the PMMA5SiO2-g-PMMA system significantly improved flame retardancy, with reduced heat release, increased limiting oxygen index (LOI), and achieved vertical burning (UL-94) ratings, demonstrating a synergistic effect superior to TPP alone. Thermal stability was enhanced, as shown by increased decomposition temperatures and residual char, attributed to promoted char formation. Additionally, the composites retained good transparency due to matched refractive indices and uniform dispersion of SiO2-g-PMMA.