Independent business support for ambitious UK companies

The Latest Science News: Get Current News on Current Scientific Developments

Hamilton Wood & Company helps forward-thinking businesses unlock value, reduce risk and support sustainable growth through R&D tax credits, property capital allowances and business finance.

  • Performance dispersion analysis of integrated internal-external ballistics for solid divert control motors under multi-source uncertainty

    Uncertainties arising from control deviations, geometric deviations, and propellant property deviations during the design, manufacturing, and operation of solid divert control motors (SDCMs) cause the thrust output to deviate from its nominal value, thereby affecting the strike accuracy of kinetic interceptors. To quantitatively evaluate the influence of these uncertainties on strike accuracy, an integrated internal-external ballistic dynamic model of the SDCM is established. Based on this model, a performance dispersion analysis method for the integrated internal-external ballistics is proposed using polynomial chaos expansions. The effects of control deviations, geometric deviations, and propellant property uncertainties on the miss distance are systematically analyzed, and Sobol’ sensitivity analysis is performed to quantify the contribution of each uncertain parameter to the variability of the miss distance. The quantitative evaluation of uncertainty effects provides valuable guidance for the optimal design of SDCMs.

  • An uncertainty-weighted Bayesian-fusion SVGMR framework for robust battery SOH estimation under partial charging conditions

    Accurate state of health (SOH) estimation for lithium-ion batteries (LIBs) is essential to ensure operational safety and reliability. However, most of existing SOH estimation studies are conducted under the assumption of complete battery charging data, which are not applicable to practical applications. Partial charging conditions and cell-to-cell degradation variability bring significant challenges for accurate online SOH estimation for LIBs. To address these issues, this paper proposes an enhanced uncertainty-weighted Bayesian-fusion sequential variational Gaussian mixture regression (BF-SVGMR) framework to improve SOH estimation accuracy and robustness under partial charging conditions, integrating historical degradation priors and incomplete charging curves into consideration. Firstly, the probabilistic relationship between extracted partial-charging features and historical capacity information is modeled, and the current-cycle capacity prediction with its uncertainty is then obtained using SVGMR. A prior representing the historical capacity degradation trend is then constructed from the previously observed capacity sequence using a sliding-window strategy. To realize online updating of priors, an uncertainty-weighted Bayesian online correction method is presented. Comparison experiments are conducted on two different datasets to verify the efficiency of the proposed framework. Results indicate that the proposed BF-SVGMR framework is superior to baseline methods, presenting excellent performance under partial charging conditions

  • Dynamic opportunistic maintenance framework for offshore wind farms in deregulated electricity markets

    The economic viability of offshore wind farms (OWFs) is heavily constrained by exorbitant operation and maintenance (O&M) costs and significant revenue losses during system downtime. While opportunistic maintenance (OM) strategies have been widely adopted to share the high fixed costs of vessel dispatch, existing frameworks largely rely on static degradation models and fail to account for the extreme short-term volatility of modern deregulated electricity markets. To bridge these gaps, this paper proposes a dynamic OM framework driven by day-ahead locational marginal prices (LMPs). Firstly, a hybrid multi-component degradation model is established. A stochastic process is developed to capture the complex crack initiation and propagation mechanisms of wind turbine blades, while the progressive aging of electromechanical components is characterized by Weibull distributions. Secondly, a dynamic and price-responsive OM thresholding mechanism is introduced. By integrating day-ahead weather forecasts and LMPs, the proposed strategy proactively groups preventive maintenance tasks during low-price windows and tightens thresholds during price spikes, thereby minimizing the expected maintenance cost. Numerical case studies based on real-world OWF configurations and historical market data demonstrate that the proposed dynamic strategy significantly outperforms traditional static OM approaches, reducing the expected lifecycle maintenance costs by 18.4% and substantially mitigating financial risks associated with electricity price volatility.

  • A systematic review on bottleneck identification in complex networks

    Complex network bottlenecks, as core constraints governing system efficiency, stability, and resilience, reflect structural imbalances among network topology, functional flows, and inter-component coupling. They substantially affect the performance and reliability of critical infrastructure and socioeconomic systems. As a prominent research topic, current studies remain fragmented in theories and methodologies, making it difficult to formulate targeted bottleneck mitigation strategies for diverse network scenarios. Meanwhile, the proliferation of big data, artificial intelligence, and other emerging technologies has reshaped traditional analytical paradigms. This paper systematically reviews state-of-the-art research, which classifies bottlenecks by their identification object, origin, scope, and temporal characteristics, and categorizes identification methods into topology-based, flow/load-based, dynamics-based, machine learning-based, and deep learning-based approaches. We further summarize future development trends and highlight key unresolved challenges.

  • Reliability allocation of multicomponent systems based on non-homogeneous pure birth process under dynamic environment

    Multicomponent systems operating in dynamic environments are affected by cumulative environmental shocks and dependent component lifetimes, which may lead to inaccurate reliability evaluation and inefficient reliability allocation if ignored. To address this issue, this paper develops a non-homogeneous pure birth process (NHPBP)-driven stochastic time-scale model for multicomponent systems. The environmental shock-counting process is modeled by an NHPBP, while the stochastic time scale is constructed as a path-dependent cumulative exposure functional driven by the whole shock history. Based on the Laplace transform of the stochastic time scale, component survival functions, joint survival functions, and reliability expressions for typical system structures are derived. Positive quadrant dependence among component lifetimes is also established. Furthermore, a cost-oriented reliability allocation model is formulated under a system-level reliability constraint and solved using a genetic algorithm. Numerical experiments on an automotive braking system show that the conventional non-homogeneous Poisson process (NHPP)-based model may overestimate system reliability under cumulative shock amplification, whereas the proposed NHPBP-based allocation model provides feasible allocation schemes under dynamic environments.

  • A case study comparison of strain measurements in micromechanical testing using optical flow and DIC

    We describe a case study on the application of an Optical Flow algorithm, using predictive velocity and pyramidal search, to the measurement of displacements in two 200 μm thick metal test specimens, compared with a traditional digital image correlation (DIC) implementation. One mesoscale tensile specimen and one mesoscale shear specimen of commercially fabricated electrodeposited nickel alloys, used in Micro Electro Mechanical Systems applications, were tested to fracture. The specimens were 200 μm thick and had gauge widths of 200 and 600 μm. Optical micrographs were taken during the tests. Displacements, strains, and mechanical properties were measured from the same sets of images using Optical Flow versus traditional DIC. The engineering stress–strain curves and shear stress vs shear strain curves from both techniques were similar (to within 1% for the engineering strains and 4%–9% for the shear strains) from the start of the tests to failure. This case study thus suggests Optical Flow shows promise as a measurement tool to complement DIC for mesoscale testing and warrants further investigation with more specimens. Potential advantages provided by Optical Flow in general include increased robustness and the potential for lower image segment search time, which could be especially beneficial for micro- and mesoscale test specimens.

  • Influence of stress-relief annealing temperature on impact toughness and fracture behavior of ti80 alloy

    Stress-relief annealing is a critical step in the engineering application of Ti80 alloy, but the effect of its temperature on impact toughness remains unclear. In this work, the Ti80 alloy was first solution treated at 970 °C for 1 h and air cooled, then subjected to stress-relief annealing at 530 °C–620 °C. The microstructure, impact toughness, and crack initiation/propagation behaviors were systematically characterized. Results show that with increasing annealing temperature, the αt needles in βtrans coarsen from 19.95 nm at 530 °C to 62.71 nm at 620 °C, while the dislocation density and subgrains in αp decrease. Thus, the hardness of both phases drops, while βtrans remains the softer phase. Impact toughness drops sharply from 50 J at 530 °C to 24 J at 620 °C. Fracture analysis shows that higher annealing temperature reduces plastic deformation in the initiation zone, shrinks the shear lip, and straightens the crack path. Mechanistic analysis reveals that microvoids preferentially nucleate inside βtrans and at αp/βtrans interfaces. The decrease in impact toughness results from the combined effects of a lower crack initiation threshold due to softening of βtrans and a weaker crack propagation resistance due to coarsening of αt.

  • Effect of drying temperature on the synthesis of porous chitosan: characterization and reactivity

    Porous chitosan has a high interconnected internal surface area. It is useful for applications such as scaffolds, drug-delivery carriers, wound dressings, filtration, or reactive precursors for the synthesis of chitosan derivatives. This research investigated the impact of oven drying temperature on the morphology, chemical structure stability, and reactivity of porous chitosan produced at the specified temperature. Porous chitosan was produced using a sol-gel method and dried in an oven at 40 °C, 50 °C, and 60 °C. The effect of drying temperature on porous chitosan was characterized using FTIR, XRD, DSC, and SEM. The reactivity of porous chitosan in the formation of chitosan carboxylate was analyzed using FTIR and carboxyl content. The characterization results showed that drying temperatures of 40 °C, 50 °C, and 60 °C did not change the chitosan backbone structure but increased apparent crystallinity and thermal stability. The increase in temperature also made the pores more compact and prone to collapse. The differences in the characteristics of porous chitosan affect its reactivity towards HNO3/H3PO4–NaNO2 in the formation of carboxylated chitosan.

  • High figure of merit optical fiber LMR sensor utilizing bilayer film of ZnO and LiF for ethanol detection

    This study theoretically investigates an optical fiber structure coated with a bilayer film of zinc oxide (ZnO) and lithium fluoride (LiF) for ethanol detection. The ZnO thin film exhibits lossy mode resonance (LMR) in the visible and near-infrared spectrum (400–1500nm), which serves as the basis for designing a refractive index (RI) sensor by appropriately selecting the ZnO thickness. To further enhance the resonance characteristics, a dielectric layer of LiF is introduced between the unclad fiber core and the ZnO coating. It Improves phase matching and generates sharper LMR dips with a narrower full width at half maximum. The proposed structure is also analyzed using two different core materials: pure silica and 4% Ge-doped silica. A comparative study of their sensing performance is also presented. Its sensing performance is examined by varying the thicknesses of the ZnO and LiF layers to identify the optimal structural parameters. The designed fiber-optic sensor is then evaluated for detecting ethanol concentrations in ethanol–water mixtures (RI =1.33 for 0% ethanol and RI =1.36 for pure ethanol) using both s- and p-polarized incident light. Calibration curves demonstrating the relationship between resonant wavelength shifts and the RI of the sample are presented. This sensor achieves excellent sensitivities of 1163 nm RIU−1 for s-polarization and 1475 nm RIU−1 for p-polarization, making it promising for the development of High-Figure of Merit biochemical sensors for potential applications.

  • Highly efficient phosphate adsorption and interface interaction mechanism by UiO-66-COOH

    Phosphate-induced eutrophication poses a critical water quality concern, and adsorption offers an effective remediation approach, yet conventional adsorbents suffer from limited capacity and poor reusability. In this study, a carboxyl-functionalized zirconium-based metal-organic framework (UiO-66-COOH) was synthesized through the hydrothermal method and deeply explored its phosphorus removal performance and potential mechanisms. Batch adsorption experiments were conducted to investigate the effects of initial solution pH, initial phosphate concentration, adsorbent dosage, and reaction temperature on the material’s phosphate adsorption behavior. Under the optimized conditions (pH = 3, dosage 0.2 g l−1), UiO-66-COOH exhibited a remarkable removal efficiency of 97.71%, with an equilibrium adsorption capacity of 48.86 mg g−1. Adsorption kinetics followed the pseudo-second-order model, indicating chemisorption-dominated behavior, while thermodynamic analysis revealed a spontaneous and endothermic process. Comprehensive characterization (such as x-ray powder diffraction, x-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy) indicated that the efficient removal of phosphate by UiO-66-COOH was attributed to the synergistic effects of pore filling, carboxyl coordination chelation, and electrostatic interactions. This study not only provides an efficient adsorbent for phosphate pollution control but also offers theoretical and experimental support for the application of functionalized MOF materials in water environment remediation.

  • A review of 3D-printed architected polymer structures as reinforcement in cementitious applications

    Additive manufacturing of architected polymer reinforcements is an emerging geometry-driven approach to improve the mechanical performance of cementitious materials. In contrast to conventional methods, it enables controlled architectures where load transfer and crack propagation are governed by topology and spatial distribution. However, comparisons are difficult due to variability in architectures, materials, processes and testing conditions. This review covers advances in 3D-printed polymer reinforcements, such as discrete and graded lattices, TPMS, auxetic, and origami-inspired structures. The reported improvements are mainly related to ductility, post-cracking response, energy absorption (up to 853%) and flexural toughness (up to 23×), with some systems showing a transition toward strain-hardening behavior. However, these values are strongly influenced by the baseline reference conditions, reinforcement ratio, polymer type, architecture, specimen geometry and testing protocol, limiting direct quantitative comparison between studies. The effects of polymer selection and manufacturing processes are also discussed. The main challenges are geometric inaccuracies, limited interface characterization, insufficient durability assessment, and lack of standard protocols. To address these, better interface design, material selection, and consistent processing–structure–property analysis are needed, which would support a more rational design framework and broader applications.

  • Effects of Ar and Kr sputtering gas on the interfaces and micro-structure of Ni/Ti multilayer

    The effect of sputtering gas, particularly the generation of energetic recoil particles, is crucial in determining interfaces and microstructural evolution of magnetron-sputtered thin films. This is especially critical for nanoscale Ni/Ti multilayers, which are core components in advanced neutron mirrors. In this work, the modulation of the interface and layer structure in Ni/Ti multilayers was comparatively investigated by varying the sputtering gas using Ar and Kr. TRIM simulations reveal that using a heavier sputtering gas (Kr) significantly reduces the energy and number of recoil particles. Comprehensive characterizations using GIXRR, diffuse scattering, XRD, and TEM demonstrate a physical trade-off: the Ar-sputtered multilayer is found to exhibit approximately 1.5 times lower interface roughness (RMS), while it shows stronger Ni (111) crystallization and larger interdiffusion. Conversely, replacing Ar with Kr reduced the crystallization and atomic intermixing, despite the relatively larger interface roughness. These findings provide useful guidance for mitigating interface defects and optimizing the fabrication of high-performance multilayer optics.

  • Integrated adsorption-photocatalysis of Xylenol Orange using Fe3O4/TiO2 composite: effects of pH, catalyst and PMS dosage, and mineralization with environmental assessment

    A magnetically recoverable Fe3O4/TiO2 composite was synthesized and applied for the removal of Xylenol Orange, a dye widely used in industrial applications, via a peroxymonosulfate assisted photocatalytic process under UV irradiation. The structural and physicochemical properties of the composite were characterized using XRD, FTIR, and SEM–EDS. Complete color removal (100%) was achieved under the optimum conditions of pH 5.0, PMS concentration of 1.0 mM, catalyst dosage of 1 g l−1, 30 min dark adsorption, and 60 min UV irradiation. An increase in the initial XO concentration (25–100 mg l−1) resulted in a decline in removal efficiency. Kinetic analysis revealed that XO degradation followed a pseudo-first-order Langmuir–Hinshelwood model. The composite maintained its activity up to the second cycle and exhibited dual catalytic behavior, involving both photocatalysis and PMS activation via Fe3O4. Life cycle assessment using the ReCiPe 2016 Midpoint (H) method indicated that energy consumption, mainly from UV irradiation, is the primary contributor to environmental impacts. These findings demonstrate an efficient and environmentally relevant approach for azo dye removal.

  • Microwave-assisted alkaline depolymerization of PET: Taguchi optimization, severity-based performance indicators, and preliminary process assessment

    Polyethylene terephthalate (PET) waste was depolymerized by microwave-assisted alkaline hydrolysis in two separate reagent systems, one based on NaOH and one on KOH, with the aim of recovering terephthalic acid (TPA) and characterizing each system at the process level. The two systems were optimized independently, each within its own operating window, using a Taguchi L9 (34) orthogonal array of four factors at three levels, with four replicates per run (36 runs per system). Because the two campaigns used different catalyst variables, TiO2 loading in the NaOH system and catalyst type (none, zinc acetate, zinc oxide) in the KOH system, the results are reported as process-oriented characterizations of each system rather than as a catalyst-matched comparison of the two cations. Analysis of variance, signal-to-noise (S/N) analysis, main-effect analysis and general linear model (GLM) regression all identified temperature as the controlling factor in both systems, followed by alkali concentration and reaction time. PET conversion approached completion at 195 °C/30 min/12 wt.% NaOH and at 200 °C/36 min/18 wt.% KOH. The GLM models were predictive (R2 ⩾ 98%; leave-one-out predicted R2 within 1.6% of R2), and residual analysis supported the model assumptions. The main methodological contribution is a pair of severity-normalized descriptors, a performance index and an apparent rate index adapted from the combined severity factor of biomass pretreatment, which read efficiency per unit of applied thermal and temporal severity rather than by conversion alone. A preliminary process assessment quantified the alkali stoichiometric excess (≈4.3–4.6-fold) and the inorganic salt by-product stream, both of which identify reagent efficiency as the main obstacle to scale-up. TPA recovery was confirmed by Fourier-transform infrared spectroscopy and 1H NMR, and product morphology was examined by scanning electron microscopy.

  • Influence of curing conditions on the long-term release of major resin-matrix monomers from conventional and bulk-fill resin composites: an in vitro liquid chromatography-tandem mass spectrometry study

    This study investigated the long-term release of bisphenol A-glycidyl methacrylate (Bis-GMA), ethoxylated bisphenol A dimethacrylate (Bis-EMA), and urethane dimethacrylate (UDMA) from conventional and bulk-fill resin composites polymerized using different light-curing units and curing times. Three bulk-fill composites and one conventional resin composite were evaluated. Eighty specimens were prepared using standardized metal molds (2 mm × 8 mm for the conventional composite and 4 mm × 8 mm for the bulk-fill composites) and polymerized using either a halogen (Optilux 501) or light-emitting diode (LED; Demi Ultra) curing unit for 20 s or 40 s (n = 5). The specimens were stored in a 75% ethanol/water solution, and monomer release was analyzed after 24 h, 1 week, 1 month, and 6 months using liquid chromatography-tandem mass spectrometry. Data were analyzed using multivariate ANOVA, repeated-measures ANOVA, Tukey HSD, and Tamhane’s T2 tests (α = 0.05). Both curing-unit type and curing time significantly influenced monomer release (p < 0.001). The LED curing unit resulted in lower monomer release than the halogen unit under the tested experimental conditions, while extending curing time from 20 s to 40 s significantly reduced monomer elution. Monomer release remained detectable throughout the six-month observation period. When all experimental conditions were considered collectively, UDMA exhibited the highest overall release and Bis-EMA the lowest, although material- and time-dependent variations were observed. Tetric EvoCeram Bulk Fill released significantly higher amounts of UDMA and Bis-GMA than the other investigated composites (p < 0.001). Within the limitations of this study, both curing conditions and material composition significantly influenced long-term monomer release. These findings highlight the combined contribution of composite formulation and curing protocol to the release behavior of major resin-matrix monomers from contemporary resin composites.