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Elastic-viscoplastic model for coarse-grained soil considering particle breakage
No full textThis paper presents a novel elastic-viscoplastic constitutive model for reproducing the time-dependent behaviour of coarse-grained soil considering particle breakage, by integrating the Unified Hardening (UH) model, the elastic-viscoplastic (EVP) model and the overstress theory. The relationship between the degree of particle breakage and the loading rate is established, and the state variables associated with the critical state of coarse-grained soil are derived to jointly consider both time and particle breakage. A new three-dimensional elastic-viscoplastic constitutive model is then constructed through combining the one-dimensional viscoplastic hardening parameter with a secondary consolidation coefficient considering particle breakage. The proposed model requires 19 parameters and it can well describe the influence of time-dependency and particle breakage to the shear, dilatancy, and compression behaviours of coarse-grained soil with various confining pressures or initial void ratios. Comparisons between the model predictions and experimental data are employed to validate the capability of the proposed model to replicate the time-dependent behaviour of coarse-grained soil
Human behaviour in fire: Knowledge foundation and temporal evolution
No full textUnderstanding human behaviour in fires (HBiF), whether in building or wildland fire contexts, is crucial for saving lives and managing evacuations. However, existing research lacks a comprehensive analysis of HBiF knowledge from both perspectives. To address this issue, we examined nearly 1900 HBiF-related research papers and their references, identifying around 6600 frequently cited references as the HBiF knowledge foundation. We focused on highly prominent items using metrics like citation frequency, burst, and centrality. By analysing cocitation patterns among these references, we unveiled current trends and waning areas of HBiF research. This study identifies knowledge gaps and potential future directions for the field, enabling both mapping of the research concerning our fundamental understanding of behavioural decision-making in fires as well as devel oping more effective life-saving strategies
Regression-Based Machine Learning for Predicting Lifting Movement Pattern Change in People with Low Back Pain
No full textMachine learning (ML) algorithms are crucial within the realm of healthcare applications. However, a comprehensive assessment of the effectiveness of regression algorithms in predicting alterations in lifting movement patterns has not been conducted. This research represents a pilot investigation using regression-based machine learning techniques to forecast alterations in trunk, hip, and knee movements subsequent to a 12-week strength training for people who have low back pain (LBP). The system uses a feature extraction algorithm to calculate the range of motion in the sagittal plane for the knee, trunk, and hip and 12 different regression machine learning algorithms. The results show that Ensemble Tree with LSBoost demonstrated the utmost accuracy in prognosticating trunk movement. Meanwhile, the Ensemble Tree approach, specifically LSBoost, exhibited the highest predictive precision for hip movement. The Gaussian regression with the kernel chosen as exponential returned the highest prediction accuracy for knee movement. These regression models hold the potential to significantly enhance the precision of visualisation of the treatment output for individuals afflicted with LBP
The first clinical implementation of real-time 6 degree-of-freedom image-guided radiotherapy for liver SABR patients
No full textPurpose: Multiple survey results have identified a demand for improved motion management for liver cancer IGRT. Until now, real-time IGRT for liver has been the domain of dedicated and expensive cancer radiotherapy systems. The purpose of this study was to clinically implement and characterise the performance of a novel real-time 6 degree-of-freedom (DoF) IGRT system, Kilovoltage Intrafraction Monitoring (KIM) for liver SABR patients. Methods/Materials: The KIM technology segmented gold fiducial markers in intra-fraction x-ray images as a surrogate for the liver tumour and converted the 2D segmented marker positions into a real-time 6DoF tumour position. Fifteen liver SABR patients were recruited and treated with KIM combined with external surrogate guidance at three radiotherapy centres in the TROG 17.03 LARK multi-institutional prospective clinical trial. Patients were either treated in breath-hold or in free breathing using the gating method. The KIM localisation accuracy and dosimetric accuracy achieved with KIM + external surrogate were measured and the results were compared to those with the estimated external surrogate alone. Results: The KIM localisation accuracy was 0.2±0.9 mm (left–right), 0.3±0.6 mm (superior-inferior) and 1.2±0.8 mm (anterior-posterior) for translations and −0.1◦±0.8◦ (left–right), 0.6◦±1.2◦ (superior-inferior) and 0.1◦±0.9◦ (anterior-posterior) for rotations. The cumulative dose to the GTV with KIM + external surrogate was always within 5% of the plan. In 2 out of 15 patients, >5% dose error would have occurred to the GTV and an organ-at-risk with external surrogate alone. Conclusions: This work demonstrates that real-time 6DoF IGRT for liver can be implemented on standard radiotherapy systems to improve treatment accuracy and safety. The observations made during the treatments highlight the potential false assurance of using traditional external surrogates to assess tumour motion in patients and the need for ongoing improvement of IGR
Recent advances in encapsulation techniques for cinnamon bioactive compounds: A review on stability, effectiveness, and potential applications
No full textCinnamon is renowned worldwide for its beneficial health-promoting properties. However, its application in the food industry faces significant challenges due to chemical instability, leading to the degradation of its bioactive compounds, as well as the development of undesirable sensory characteristics caused by the precipitation of salivary proteins by the bioactives. To address these issues, encapsulation methods (both micro and nano) have been developed and studied extensively. This review focuses on recent advances in such encapsulation techniques used to safeguard and deliver cinnamon bioactives, with special emphasis on the spray drying method. The methods employed to evaluate the physicochemical, rheological, and sensorial properties of nano and microparticles are also comprehensively reviewed. The review addresses the challenges associated with encapsulation, including encapsulation efficiency, long-term stability, and release kinetics, and proposes potential strategies to overcome these challenges. Furthermore, the paper presents future perspectives and research directions in cinnamon encapsulation, shedding light on novel materials, advanced characterization techniques, and hybrid encapsulation systems. Overall, encapsulation demonstrates the potential to preserve and harness the therapeutic benefits of cinnamon's bioactive compounds for a wide array of food, pharmaceutical, and nutraceutical applications. With ongoing research and advancements in encapsulation techniques, cinnamon bioactives can be effectively utilized to develop functional and health-enhancing products, catering to the diverse needs of consumers worldwide
Strength and resilient modulus characteristics of emulsion-stabilised demolition wastes in pavement structures
No full textThe use of bitumen emulsion has commonly been limited to pavement surface treatments or stabilising virgin aggregates. There is a lack of experimental evidence about the resilient modulus responses of bitumen emulsion-stabilised recycled demolition wastes in pavement applications. The aim of this study is to evaluate the effect of bitumen emulsion on the tensile strength and resilient modulus responses of recycled crushed concrete aggregate and crushed brick for pavement base/subbase course applications. A type of slow-set anionic bitumen emulsion was used at different contents of 0, 1, 2, and 3 % by dry weight of aggregates to prepare compacted specimens. The specimens were dried back to 70 and 90 % of the compaction moisture content to simulate the field conditions. Specimens were next investigated through a comprehensive testing program, including indirect tensile strength, indirect tensile modulus, and repeated triaxial loading tests. Results showed that the tensile strength of the mixtures generally increased as the emulsion content increased. The inclusion of 2 % and 3 % bitumen emulsion to RCC and CB provided the highest indirect tensile resilient modulus (ITMr) at 359 and 310 MPa, respectively, for those samples cured for 3 h. The highest ITMr results were obtained from samples cured for 3 days at 40 °C in a dry state with the inclusion of 2 % emulsion. For CB and RCC specimens, the results were 2808 and 3361 MPa, respectively. However, specimens of CB and RCC with 3 % emulsion that were cured for 3 days at 40 °C and then soaked in water at 25 °C exhibited the highest ITMr at 1981 and 2900 MPa, respectively. The resilient modulus in the majority of the specimens peaked at 2 % emulsion content, which was recommended as the optimum emulsion content. Results also indicated an enhanced resistance to moisture damage in demolition wastes through emulsion stabilisation. This study proposes, validates and promotes the sustainable approach of emulsion stabilisation of recycled aggregates used in the construction of pavement structures
Direct synthesis of CsPbX3 perovskite nanocrystal assemblies
No full textInorganic CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) possess many advantageous optoelectronic properties, making them an attractive candidate for light emitting diodes, lasers, or photodetector applications. Such perovskite NCs can form extended assemblies that further modify their bandgap and emission wavelength. In this article, a facile direct synthesis of CsPbX3 NC assemblies that are 1 μm in size and are composed of 10 nm-sized NC building blocks is reported. The direct synthesis of these assemblies with a conventional hot-injection method of the NCs is achieved through the judicious selection of the solvent, ligands, and reaction stoichiometry. Only under selective reaction conditions where the surface ligand environment is tuned to enhance the hydrophobic interactions between ligand chains of neighbouring NCs is self-assembly achieved. These assemblies possess narrow and red-shifted photoluminescence compared to their isolated NC counterparts, which further expands the colour gamut that can be rendered from inorganic perovskites. This is demonstrated through simple down-converting light emitters
Cu and Zn promoted Al-fumarate metal organic frameworks for electrocatalytic CO2 reduction
No full textMetal organic frameworks (MOFs) are attractive materials to generate multifunctional catalysts for the electrocatalytic reduction of CO2 to hydrocarbons. Here we report the synthesis of Cu and Zn modified Al-fumarate (Al-fum) MOFs, in which Zn promotes the selective reduction of CO2 to CO and Cu promotes CO reduction to oxygenates and hydrocarbons in an electrocatalytic cascade. Cu and Zn nanoparticles (NPs) were introduced to the Al-fum MOF by a double solvent method to promote in-pore metal deposition, and the resulting reduced Cu-Zn@Al-fum drop-cast on a hydrophobic gas diffusion electrode for electrochemical study. Cu-Zn@Al-fum is active for CO2 electroreduction, with the Cu and Zn loading influencing the product yields. The highest faradaic efficiency (FE) of 62% is achieved at −1.0 V vs. RHE for the conversion of CO2 into CO, HCOOH, CH4, C2H4 and C2H5OH, with a FE of 28% to CH4, C2H4 and C2H5OH at pH 6.8. Al-fum MOF is a chemically robust matrix to disperse Cu and Zn NPs, improving electrocatalyst lifetime during CO2 reduction by minimizing transition metal aggregation during electrode operation
Dynamic capabilities that matter for business failure versus survival
No full textDue to the severity and length of the COVID-19 pandemic, some businesses have failed whereas others, including those in the same industry, have survived. Drawing on dynamic capability theory, we explored the dynamic capabilities, whose presence or absence are conditions for business failure or survival. We conducted 16 in-depth semi-structured interviews with owners/executives of firms from the travel and tourism, catering and hospitality, and agricultural export industries in India. Using fuzzy set qualitative comparative analysis (fsQCA) technique, we found three causal configurations for the business failure phenomenon, and two causal configurations for business survival phenomenon. The absence of collaborative capability with key stakeholders was observed as key to business failure, and the absence of leadership adaptive capability and the ability to leverage government support were found in two of the three causal configurations. In contrast, leadership adaptive capability and collaborative capability were present in the two causal configurations for business survival. Contrary to common viewpoints, digital transformation capability was neither sufficient to prevent failure nor necessary to ensure survival. By focusing on firms' dynamic capabilities as the conditions that differentiate business failure from survival, this study advances scholarship, and offers guidance to managers on navigating through a crisis
Joint effect of entrepreneurship and dynamic capabilities on firm performance: an empirical investigation among ICT-SMEs
No full textPurpose: With the focus on the context of small and medium-sized enterprises (SMEs), this study aims to investigate the joint effects of entrepreneurial leadership, entrepreneurial orientation and dynamic capabilities and the mechanisms of how these factors influence firm performance. Design/methodology/approach: A survey from 319 managers in information and communications technology SMEs in Vietnam was conducted, and structural equation modeling was adopted to analyze the collected data. Findings: The results confirm that dynamic capabilities directly influence firm performance and serve as a mediator that connects entrepreneurial leadership and entrepreneurial orientation with firm performance. Additionally, entrepreneurial leadership was found to have a significant positive impact on entrepreneurial orientation. Originality/value: This research augments the understanding of entrepreneurship and dynamic capabilities literature by examining the joint effects and mechanisms of how entrepreneurial leadership, entrepreneurial orientation and dynamic capabilities interact to enhance SMEs' performance. Furthermore, this study provides empirical evidence of the strategies that SMEs should pursue to attain favorable performance outcomes