Search Results (131)

The cold recycling (CR) technique is gaining traction, with an increasing demand for sustainable pavement construction practices. Cold in-place recycling (CIR) and cold central plant recycling (CCPR) are two strategies under the umbrella of cold recycling. These techniques use reclaimed asphalt pavement (RAP) to rehabilitate pavement, and CCPR offers the added advantage of utilizing stockpiled RAP. While many agencies have expertise in cold recycling techniques including CCPR, the lack of pavement performance data prevented the largescale implementation of these technologies. Recent studies in high-traffic volume applications demonstrate that CCPR technology can be implemented on the entire road network across all traffic levels. This reignited interest in the widespread implementation of CCPR. Therefore, the purpose of this study is to provide agencies with the most up-to-date information on CCPR to help them make informed decisions. To this end, this paper comprehensively reviews the mix-design for CCPR, the structural design of pavements containing CCPR layers, best construction practices, and the agency experience in using this technology on high-traffic volume roads to provide in-depth information on the steps to follow from project selection to field implementation. The findings specify the suitable laboratory curing conditions to achieve the optimum mix design and specimen preparation procedures to accurately capture the material properties. Additionally, this review synthesizes existing quantitative data from previous studies, providing context for the comparison of findings, where applicable. The empirical and mechanistic–empirical design inputs, along with the limitations of AASHTOWare Pavement ME software for analyzing this non-conventional material, are also presented. Full article

Advances in the field of asteroid dynamics continue to yield new knowledge regarding the behavior and characteristics of asteroids, allowing unprecedented levels of accuracy for predicting trajectories and contributing to impact avoidance strategies. Meanwhile, more detailed information regarding the physical composition of asteroids has reignited interest in asteroid mining as a potential new resource sector. This article considers some of the technical, ethical, legal and social issues facing global planetary defense efforts and off-world mining proposals. It considers issues such as claim jumping, weaponization of the space environment and ownership issues for resources extracted from space. Full article

To thoroughly analyze the high-frequency and high-amplitude electromagnetic disturbances generated during disconnector operation, this paper proposes an equivalent modeling approach based on dynamic arc behavior. The model incorporates the resistance, inductance, and capacitance characteristics of the arc and consists of four main modules: arc reignition, arc extinction, arc resistance control, and switch control. Complete logical coordination among these modules is designed to enhance the model’s performance in terms of dynamic response and modeling accuracy compared to traditional methods. By systematically comparing simulation results with experimental data and conventional model outputs, the effectiveness and reliability of the proposed model in accurately reflecting the operational characteristics of disconnectors are validated. Furthermore, a comparative analysis of transient waveform characteristics from both experiment and simulation is conducted, with key parameters extracted and probability density functions constructed. The results demonstrate the high-precision fitting capability of the model and further reveal the statistical distribution patterns of very fast transient overvoltage single-pulse characteristics. Full article

The construction sector’s increasing eco-consciousness is driving the need for higher-performance wood-based engineered products from underutilized timber resources, such as small-diameter trees from hazardous fuel treatments of our forests. Strand-based products, including oriented strand board (OSB) and lumber (OSL), are widely used. However, hot-pressing during their manufacturing generates approximately 10% waste, which includes a substantial amount of resinated strands that are landfilled. The huge potential of using strand-based products has led to many studies and growing interest in strand-based three-dimensional sandwich panels that can be used as wall, floor, or roofing panels. As the market grows, understanding the recyclability of these resinated strands becomes crucial. This study investigates the feasibility of using re-resinated waste strands that were collected during lab-scale production of strand-based panels. Results demonstrate significant improvements in dimensional stability, mechanical properties, and fire resistance. Specifically, recycling increased internal bond strength, flexural strength, time to ignition, time to flameout, mass loss, and time to peak heat release rate by 107%, 44%, 58%, 35%, 51%, and 27%, respectively, and helped decrease water absorption and thickness swell by 51% and 58%, respectively. Full article

Firefighting foam is widely recognized for its excellent fire suppression performance. However, research on the effect of foam expansion ratio on the suppression efficiency of forest surface fires remains limited. In this study, the expansion ratio was adjusted by varying the air-to-liquid ratio in a compressed air foam system, and laboratory-scale foam suppression experiments were conducted. Key performance indicators, including extinguishing coverage time, internal cooling rate, and resistance to reignition, were systematically measured. The effects of expansion ratio on the diffusion and penetration behavior of foam on the fuel bed surface were then investigated to understand how these characteristics influence suppression performance. The results indicate that both excessively low and high expansion ratios can weaken fire suppression effectiveness. Low-expansion foam, characterized by low viscosity and high water content, exhibits strong local penetration and cooling capabilities. However, it struggles to rapidly cover the fuel bed surface and isolate oxygen, thereby reducing the overall suppression efficiency. In contrast, high-expansion foam has greater viscosity, allowing it to spread across the fuel bed surface under pressure gradient forces and form a stable coverage layer, effectively limiting the oxygen supply required for combustion. However, its limited depth penetration and lower water content reduce internal cooling efficiency, increasing the risk of reignition. The optimal expansion ratio was determined to be 15.1. Additionally, increasing the liquid supply flow rate significantly improved suppression performance; however, this improvement plateaued when the flow rate exceeded 10 L/min. Full article

The growing disparity between the demand for donor hearts and their availability has reignited interest in donation after circulatory death (DCD) heart transplantation. Historically, DCD heart transplantation has been overshadowed by donation after brain death (DBD) due to ethical and preservation challenges. However, recent advancements in procurement techniques allow for evaluation of the donor heart and enable the broader utilization of DCD donors. While challenges remain, early outcomes suggest comparable survival rates between DCD and DBD heart transplantation. This review provides a comprehensive overview of the historical evolution, current practices, and future directions of DCD heart transplantation. Here, we emphasize its potential to expand the heart donor pool and alleviate the organ shortage crisis. Full article

Due to the special properties of synthetic aperture radar (SAR) images, they are widely used in maritime applications, such as detecting ships at sea. To perform ship detection in SAR images, existing algorithms commonly utilize convolutional neural network (CNN). However, the challenges in acquiring SAR images and the imaging noise hinder CNN in performing SAR ship-detection tasks. In this paper, we revisit the relationship between SAR expert features and network abstract features, and propose an expert-feature-based convolutional neural network (EFCNet). Specifically, we exploit the inherent physical properties of SAR images by manually extracting a range of expert features, including electromagnetic scattering, geometric structure, and grayscale statistics. These expert features are then adaptively integrated with abstract CNN features through a newly designed multi-source features association module, which improves the common CNN’s capability to recognize ship targets. Experiment results on the SSDD demonstrate that EFCNet outperforms general CNN approaches. Furthermore, EFCNet achieves comparable detection performance to baseline methods while utilizing only 70% of the data capacity, highlighting its efficiency. This work aims to reignite interest in leveraging expert features in remote sensing tasks and offers promising avenues for improved SAR image interpretation. Full article

Since COVID-19, there has been an increase in the utilization of food banks owing to a number of factors, including a reduction in household income due to job losses and an increase in the cost of living, which has affected people on low incomes. In this paper, we explain how people that are in need of assistance and have limited knowledge of service provision can be remotivated through regaining their self-esteem. This is achieved through various forms of intervention. By adopting a metaphorical approach, we conceptually explore how intervention provided by a social inclusion community center stimulates recipients to re-ignite their desire for self-improvement. This is achieved through an analogy made, comparing a Formula 1 motor racing team servicing a car during a pit-stop and a person (recipient) in need of food visiting a food bank to collect a food parcel. Based on a conceptual analysis, we propose a framework outlining the interactional process involving the social inclusion community center staff and a recipient, whereby the recipient becomes, through empowerment, an external operant actor and resource integrator for the social inclusion community center. This is achieved through a circular value co-creation process. Through the circular motion of the value co-creation, an external operant actor regains self-confidence due to gaining a sense of belonging and feeling inspired to contribute to the community they are associated with. Full article

Statistics indicate that over 90% of large forest fires experience re-ignition after initial extinction. However, research on the mechanisms triggering forest fire rekindling remains largely empirical, lacking an intuitive 3D mathematical model to elucidate the process. To fill this gap, this study proposes a digital twin-based forest fire re-ignition trigger model to investigate the transition from smoldering to flaming combustion. Leveraging digital twin technology, a virtual forest environment was constructed to assess the influence of ambient wind conditions and terrain slope on the smoldering-to-flaming (StF) transition based on historical rekindling data. Subsequently, logistic regression was employed in a reverse iterative process to update the model parameters, thereby establishing a matching mechanism between the model predictions and the observed rekindling states. This approach enables the adaptive adjustment of the weights assigned to key variables (e.g., wind speed and slope) and facilitates the prediction of forest fire rekindling probability within the virtual environment. Additionally, digital twin simulations are employed to assess the 3D firefighting effectiveness of unmanned aerial vehicles (UAVs) deploying hydrogel and solidified foam extinguishing agents. This visualization of the firefighting process provides valuable insights, aiding in the development of more effective strategies for preventing and controlling fire re-ignition. Full article

The recent surge in popularity of generative artificial intelligence (GenAI) tools like ChatGPT has reignited global interest in AI, a technology with a well-established history spanning several decades. The California Department of Water Resources (DWR) has been at the forefront of this field, leveraging Artificial Neural Networks (ANNs), a core technique in machine learning (ML), which is a subfield of AI, for water and environmental modeling (WEM) since the early 1990s. While protocols for WEM exist in California, they were designed primarily for traditional statistical or process-based models that rely on predefined equations and physical principles. In contrast, ML models learn patterns from data and require different development methodologies, which existing protocols do not address. This study, drawing on DWR’s extensive experience in ML, addresses this gap by developing standardized protocols for the development and implementation of ML models in WEM in California. The proposed protocols cover four key phases of ML development and implementation: (1) problem definition, ensuring clear objectives and contextual understanding; (2) data preparation, emphasizing standardized collection, quality control, and accessibility; (3) model development, advocating for a progression from simple models to hybrid and ensemble approaches while integrating domain knowledge for improved accuracy; and (4) model deployment, highlighting documentation, training, and open-source practices to enhance transparency and collaboration. A case study is provided to demonstrate the practical application of these protocols step by step. Once implemented, these protocols can help achieve standardization, quality assurance, interoperability, and transparency in water and environmental modeling using machine learning in California. Full article

When a 35 kV distribution network has the problem of insufficient reactive power, the input of a shunt reactor is a common compensation method. Vacuum circuit breakers are widely used in 35 kV distribution networks because of their superior arc extinguishing performance and convenient maintenance. However, in recent years, accidents involving vacuum circuit breakers breaking shunt reactors have occurred more frequently in China, such as high-frequency phase-to-phase short circuits, inter-turn burning losses, bus outlet short circuits, etc., which can cause serious damage and pose a greater threat to the safety of the power system. This paper focuses on the switching overvoltage generated by the vacuum circuit breaker cutting off the shunt reactor. Firstly, the mechanism of overvoltage generation is analyzed theoretically. It is concluded that the equivalent chopping current of the other two phases caused by the continuous reignition of the first open phase is the root cause of the high-amplitude interphase overvoltage. Based on the MODELS custom programming module in EMTP/ATP, according to the process of breaking and reigniting the circuit breaker, this paper uses Fortran language to compile the program and establishes a model of a vacuum circuit breaker, including power frequency current interception, high-frequency current, zero-crossing, breaking, and arc reignition modules. The vacuum circuit breaker is simulated for hundreds of continuous reignitions in milliseconds. Finally, a simulation study on the overvoltage suppression measures of a 35 kV shunt reactor is carried out. The comprehensive comparison of various suppression measures provides a reference for the reasonable selection of actual engineering conditions. Full article

A physically and chemically cross-linked Al³⁺-CS/PAM-MBA dual-network gel with enhanced fire-suppression performance was prepared using chitosan (CS), acrylamide (AM), and N,N’-methylenebisacrylamide (MBA) as base materials. The first network was formed through the covalent cross-linking of polyacrylamide (PAM) with MBA, while the second network was established by crosslinking CS molecules with Al³⁺ ions. The optimal gel ratio was determined by evaluating its formation time and viscosity. The fire prevention and extinguishing performance of the gel was assessed through thermal stability analysis, temperature-programmed studies, infrared spectroscopy, thermal analysis, and fire-extinguishing experiments. The results indicated that the Al³⁺-CS/PAM-MBA dual-network gel exhibited excellent thermal stability and a strong self-ignition inhibition effect, effectively suppressing coal spontaneous combustion and oxidation. The gel achieved this by chemically inactivating coal molecules, disrupting the functional groups closely associated with coal–oxygen reactions and thereby hindering these reactions. Fire-extinguishing tests demonstrated that the gel restrained coal from spontaneous combustion. Upon application, the gel rapidly reduced the coal temperature, making re-ignition less likely. Full article

This paper presents a mission concept for a Low Earth Orbit (LEO) satellite equipped with a payload for space experiments, designed to be recovered on Earth post-mission. The focus of this study is on developing a mission concept with fast de-orbit and accurate landing capability for a small satellite payload. Two re-entry configurations are analyzed: one employing a deployable aero-brake heat shield for aerodynamic descent and another integrating a propulsion system. Aerodynamic analysis of the capsule, including drag coefficient and stability at relevant altitudes, was conducted using the Direct Simulation Monte Carlo (DSMC) method. A trade-off analysis, accounting for uncertainties such as C_D, atmospheric density, and ignition timing, revealed significant differences in mission profiles. A propulsion system providing a ΔV of approximately 100 m/s reduces descent time from 54 days (aerodynamic-only re-entry) to under 1 h, without altering trajectory. Drag-related uncertainties contribute to a landing dispersion of ~100 km, while a ±1% error in total impulse increases dispersion to 400 km. A monopropellant rocket engine was preliminarily designed, meeting constraints such as catalytic chamber pressure and performance targets. The resulting thruster, weighing under 4 kg and contained within a 250 mm-high, 350 mm-diameter cylinder, supports three potential component layouts. Full article

Alkali-activated materials are promising alternatives to cement. This study investigated the effects of the silica content, particle size, and replacement ratio of rice husk ash (RHA) on the compressive strength and the optimization of these parameters. Seventeen mixtures with different materials were tested to evaluate their compressive strengths. Three levels of particle size, silica content, and RHA replacement ratio were used. The effects of RHA characteristics on the compressive strength were investigated based on Archimedes porosity, pH, ignition loss, and X-ray diffraction. The experimental results reveal that the replacement ratio of RHA was p-values < 0.002, which affected the compressive strength compared with the particle size (p-values < 0.450) and silica content of the RHA (p-values < 0.017). It was confirmed that the optimum values of particle size, silica content, and replacement ratio of RHA were 50 µm, 90%, and 15 wt.%, respectively. After re-testing, the compressive strength of mortar made with the optimum values was 49.8 MPa. This increase in compressive strength was also found to be closely related to the porosity, pH, and ignition loss of the paste. It was confirmed that the replacement ratio of RHA increased with decreasing porosity and pH and increasing ignition loss, which was related to the formation of calcite and C-S-H. Full article

This study investigates how religious rhetoric and popular mobilisation contributed to the preservation and propagation of Daoist traditions at the mountain Maoshan 茅山 from late Qing to Republican China (1864–1937), focusing particularly on the corpus of religious texts related to Maoshan and its tutelary gods, the Three Mao Lords 三茅真君. Through a detailed analysis of primary sources, including editions of the Maoshan Gazetteer, liturgical manuals such as the scripture (jing 經), litany (chan 懺), and performative texts such as the precious scroll (baojuan 寶卷) of the Three Mao Lords, this study identifies six key rhetoric strategies employed by Maoshan Daoists, using the acronym IMPACT: (1) Incorporation: Appending miracle tales (lingyan ji 靈驗記) and divine medicine (xianfang 仙方) to address immediate and practical needs of contemporary society; (2) Memory: Preserving doctrinal continuity while invoking cultural nostalgia to reinforce connections to traditional values and heritage; (3) Performance: Collaborating with professional storytellers to disseminate vernacularized texts through oral performances, thereby reaching broader audiences including the illiterate. (4) Abridgment: Condensing lengthy texts into concise and accessible formats; (5) Canonization: Elevating the divine status of deities through spirit-writing, thereby enhancing their religious authority; (6) Translation: Rendering classical texts into vernacular language for broader accessibility. Building upon J.L. Austin’s speech act theory, this study reconceptualizes these textual innovations as a form of “text acts”, arguing that Maoshan texts did not merely transmit religious doctrine but actively shaped pilgrimages and devotional practices through their illocutionary and perlocutionary force. Additionally, this study also highlights the crucial role of social networks, particularly the efforts of key individuals such as Zhang Hefeng 張鶴峰 (fl. 1860–1864), Long Zehou 龍澤厚 (1860–1945), Jiang Daomin 江導岷 (1867–1939), Wang Yiting 王一亭 (1867–1938) and Teng Ruizhi 滕瑞芝 (fl. 1920–1947) who facilitated the reconstruction, reprinting and dissemination of these texts. Furthermore, this study considers pilgrimages to Maoshan as a form of popular mobilisation and resistance to anti-clerical and anti-superstition campaigns, illustrating how, against all odds, Maoshan emerged as a site where religious devotion and economic activity coalesced to sustain the local communities. Ultimately, despite the challenges identified in applying speech act theory to textual practices, the findings conclude that the survival and revival of Daoist traditions at Maoshan was not only a result of textual retention and innovation but also a testament to how religious rhetoric, when coupled with strategic social engagement, can fuel popular mobilisation, reignite collective devotion, and reshape cultural landscapes in transformative ways. Full article