Search Results (208)

Hydrogen is a carbon-neutral fuel, so in theory it holds enormous potential. The use of hydrogen as a fuel for traditional internal combustion engines is becoming increasingly prominent. The authors now have the opportunity to retrofit a single-cylinder diesel research engine to an engine with hydrogen operation. For this reason, before that conversion, they prepared a comprehensive review study regarding hydrogen. Firstly, the study analyzes the most essential properties of hydrogen in terms of mixture formation and combustion compared to diesel. After that, it deals with indirect and direct injection, and what kind of combustion processes can occur. Since there is a possibility of pre-ignition, backfire, and knocking, the process can be dangerous in the case of indirect mixture formation, and so a short subsection is devoted to these uncontrolled combustion phenomena. The next subsection shows how important, in many ways, a special spark plug and ignition system are for hydrogen operation. The next part of the study provides a detailed presentation of the possible combustion chamber design for operation with hydrogen fuel. The last section reveals how many parameters can be focused on analyzing the hydrogen’s combustion process. The authors conclude that intake manifold injection and a Heron-like combustion chamber design, with a special spark plug with an ignition system, would be an appropriate solution. Full article

Semisubmersible floating structures are becoming the predominant understructure type for floating offshore wind turbines (FOWTs) worldwide. As FOWTs are erected far away from land and in deep seas, they inevitably suffer violent and complicated sea conditions, including extreme waves and winds. Mooring lines are the representative flexible members of the whole structure and are likely to incur damage due to years of impact, corrosion, or fatigue. To improve mooring redundancy at each azimuth angle around a wind turbine, a group of mooring lines are configured in the same direction instead of just one mooring line. This study focuses on the mooring failure problems that would probably occur in a realistic redundant mooring system of a semisubmersible FOWT, and the worst residual mooring layout is considered. An FOWT numerical model with a 3 × 3 mooring system is established in terms of 3D potential flow and BEM (blade element momentum) theories, and aero-hydro floating-body mooring coupled analyses are performed to discuss the subsequent time histories of dynamic responses after different types of mooring failure. As under extreme failure conditions, the final horizontal offsets of the structure and the layout of the residual mooring system are evaluated under still water, design, and extreme environmental conditions. The results show that the transient tension in up-wave mooring lines can reach more than 12,000 kN under extreme environmental conditions, inducing further failure of the whole chain group. Then, a deflection angle of 60° may occur on the residual laid chain, which may bring about dangerous anchor dragging. Full article

This is a review/research paper on anomalies applied in a bottom–up approach to standard model and gravity. It is divided into two parts. The first consists of a proper review of anomalies in quantum field theories. Anomalies are analyzed according to three different methods: a perturbative one based on a Feynman diagram, a non-perturbative one relying on the Schwinger–DeWitt approach, and, third, one hinging on the Atiyah–Singer family’s index theorem. The three methods are applied both to chiral gauge anomalies and trace anomalies. The fundamental distinction, which our presentation leads to, is between obstructive (O) and non-obstructive (NO) anomalies. The former is tied to the non-existence of fermion propagators, which fatally maim the corresponding theory. In the second part, we apply this analysis to the SM and a variety of its extensions, which are immersed in a gravitational background, and we find that they are all plagued by a residual chiral trace anomaly. To completely eliminate all kinds of dangerous anomalies in SM-like theories, we propose a somewhat unconventional scheme and exemplify it by means of an explicit model. The latter is a left–right symmetric model. We embed it in a Weyl geometry to render it a conformal invariant. We then deal with some of its quantum aspects, particularly its even (NO) trace anomalies and the means to preserve its conformal invariance at the quantum level. We briefly review renormalization and unitarity in the framework of similar models discussed in the existing literature. Finally, we present a possible (conjectural) application of the model to describe the junction between cosmology and quantum field theory. Full article

The corrosion of the rotating axis pins of the short suspender will lead to the rotating restriction of its end, which will lead to the corrosion of the parallel wires and affect the performance of the short suspender. In this study, the technical condition of the rotating restricted short suspender unfixed from the suspension bridge was carefully detected. An axial tensile performance test was carried out on these short suspenders, and the subsequent availability of the rotating restricted suspender was evaluated based on the size of the fracture gap. The rotationally limited working conditions of these short suspenders were skillfully simulated by the specially designed tooling, and the fatigue performance test of the rotating restricted short suspender was carried out. A simplified simulation method was proposed based on the random traffic theory. By introducing traffic data obtained from the WIM system, the stress response of the short suspenders caused by vehicles on each lane was simulated, and the simulation results were converted by the rain flow counting method. The residual life of the rotating restricted short suspender was predicted by the comparison between the fatigue test results and the fitting curve of the simulation results. From this study, several of the following conclusions can be summarized: The measured fracture gap size is negatively correlated with the effective area of the suspender, and the gap size of 8mm is a key value. When the fatigue load cycle reaches 345,000 times, the suspender is already in a dangerous state. Additionally, the fractured gap size is considered as the judgment basis for the usability of rotating restricted short suspenders. When the gap size is less than 8 mm, the suspender can be continually used after maintenance and should be updated after 6 years. Otherwise, the suspender needs to be replaced immediately. Full article

As China’s construction industry pays increasing attention to occupational health, prefabricated buildings, as an important direction for industry transformation, are gradually gaining widespread attention. However, because relevant management regulations have not yet been perfected, work-related injuries still occur from time to time. In order to comprehensively analyze safety risks in prefabricated building construction (PBC), this article systematically discusses construction safety risks and their causal relationships based on accident data and complex network theory. By constructing a network model of safety accident causes in PBC, the topology of the network was evaluated, the relationship between accidents and safety risks was revealed, and key safety risk factors were identified. Research shows that the attack strategies of betweenness centrality and degree centrality can significantly affect the stability of the network structure, and the EffG attack strategy performs better in identifying key nodes. In addition, human factors and management factors are the main causes of accidents. In particular, the two factors of insufficient safety education and training and insufficient safety hazard investigation play a decisive role in network connectivity. This study also further analyzed the formation probabilities of critical risk paths for various types of accidents. Among them, object impact accidents have the highest probability of occurrence, reaching 0.19779, while collapse accidents have the lowest probability of occurrence at only 0.02046. In response to these findings, this article proposes strategies, such as strengthening safety training, regular hidden danger inspections, and optimizing on-site management, to reduce construction safety risks and promote the sustainable development of the construction industry. Full article

Just war theory, significantly shaped by Christian moral theology, has provided a prominent ethical framework for discussions on the justice of war. Numerous works have been published on classical Chinese counterparts, including passages from the Mengzi, Mozi, Xunzi, and Huangdi Sijing. Although the Zhuangzi frequently discusses warfare, it has been largely overlooked in this field of research because its war ethics do not revolve around any concept similar to that of justice. Based on Zhuangzian critiques of Confucian and Mohist views on justice, this paper tentatively reconstructs Zhuangzian war ethics. This reconstruction reveals a perspective that the concept of just war or justified war is inherently problematic, and promoting such ideas can be perilous and even morally questionable. The belief that just war theory can help us identify a “just side” to morally condemn or legally restrain aggressors is a dangerous illusion. In practice, this approach fails to prevent wars and often exacerbates conflict. According to the Zhuangzian perspective, during wars, states do not operate as traditional political entities with universal jurisdiction and centralized authority. Instead, they resemble rivers and lakes with indistinct boundaries, rendering the concepts of justice and punishment largely irrelevant. A practical peace strategy, therefore, must abandon the pursuit of administering justice and punishing wrongdoers. Instead, it should focus on strategies that facilitate the involved parties to “forget” their grudges and start their peaceful relationship anew. Full article

To attain a low Energy Efficiency Design Index (EEDI), large ships possibly lack the necessary propulsion power to avoid stranding in case of strong adverse wind and wave conditions. To estimate this danger, here, the longitudinal and transverse drift force and the yaw drift moment caused by regular waves of arbitrary frequency and direction are computed using a 3-dimensional Rankine panel method. In many cases, drift forces are larger in shallow than in deep water. Therefore, the theory for computing drift force and moment is extended to shallow water. As published results for shallow water are lacking, the method is verified only for deep water by comparisons with results of model experiments and CFD computations for three ships. For one of them, the dependence of non-dimensional coefficients of longitudinal and transverse drift force and of the drift yaw moment on wave frequency, wave angle, water depth and ship speed is shown. The source files of the programs used for these computations may be obtained from the author if an adequate fee is donated to the Medecins Sans Frontieres or to the author. Full article

Doxorubicin (DOX) has been widely used as a cytotoxic chemotherapeutic. However, DOX has a number of side effects, such as myelotoxicity or gonadotoxicity, the most dangerous of which is cardiotoxicity. Cardiotoxicity can manifest as cardiac arrhythmias, myocarditis, and pericarditis; life-threatening late cardiotoxicity can result in heart failure months or years after the completion of chemotherapy. The development of late cardiomyopathy is not yet fully understood. The most important question is how DOX reprograms the cardiomyocyte, after which DOX is excreted from the body, initially without symptoms. However, clinically overt cardiomyopathy develops over the following months and years. Since the 1980s, DOX-induced disorders in cardiomyocytes have been thought to be related to oxidative stress and dependent on the Fe/reactive oxygen species (ROS) mechanism. That line of evidence was supported by dexrazoxane (DEX) protection, the only Food and Drug Administration (FDA)-approved drug for preventing DOX-induced cardiomyopathy, which complexes iron. Thus, the hypothesis related to Fe/ROS provides a plausible explanation for the induction of the development of late cardiomyopathy via DOX. However, in subsequent studies, DEX was used to identify another important mechanism in DOX-induced cardiomyopathy that is related to topoisomerase 2β (Top2β). Does the Top2β hypothesis explain the mechanisms of the development of DOX-dependent late heart failure? Several of these mechanisms have been identified to date, proving the involvement of Top2β in the regulation of the redox balance, including oxidative stress. Thus, the development of late cardiomyopathy can be explained based on mechanisms related to Top2β. In this review, we highlight free radical theory, iron imbalance, calcium overload, and finally, a theory based on Top2β. Full article

Mine transboundary mining has been occurring frequently in recent years, and this illegal behavior has brought great potential danger to mine safety while also causing greater losses of state-owned assets. However, the current method of monitoring transboundary mining is still mainly based on underground verification by supervisors, which is far from meeting the demand for supervision. Microseismic monitoring technology is effective for monitoring transboundary mining due to its ability to locate vibration signals. For mine transboundary mining monitoring, this paper proposes a microseismic electronic fence method focusing on mine boundary locating, which differs from the routine microseismic monitoring used in mining operations. This method focuses its key monitoring area on the mine boundary. The deployment mode, number of sensors, and localization theory are analyzed, and numerical simulation and field measurement data analysis results show that the microseismic electronic fence method can achieve a localization accuracy of 15–20 m for underground microseismic events in the vicinity of mine boundaries, which can be effectively applied to the monitoring of transboundary mining activities. Full article

The existing research on security risk often focuses on specific types of crime, overlooking an integrated assessment of security risk by leveraging existing police resources. Thus, we draw on crime geography theories, integrating public security business data, socioeconomic data, and spatial analysis techniques, to identify integrated risk points and areas by examining the distribution of police resources and related factors and their influence on security risk. The findings indicate that security risk areas encompass high-incidence areas of public security issues, locations with concentrations of dangerous individuals and key facilities, and regions with a limited police presence, characterized by dense populations, diverse urban functions, high crime probabilities, and inadequate supervision. While both police resources and security risk are concentrated in urban areas, the latter exhibits a more scattered distribution on the urban periphery, suggesting opportunities to optimize resource allocation by extending police coverage to risk hotspots lacking patrol stations. Notably, Level 1 security risk areas often coincide with areas lacking a police presence, underscoring the need for strategic resource allocation. By comprehensively assessing the impact of police resources and public security data on spatial risk distribution, this study provides valuable insights for public security management and police operations. Full article

During coal mining, sudden inrushes of water from the floor pose significant risks, seriously affecting mine safety. This study utilizes the 3602 working face of the Chenmanzhuang coal mine as a case study, and the original influencing factors were downscaled using principal component analysis (PCA) to obtain four key evaluation factors: water inflow, aquiclude thickness, water pressure, and exposed limestone thickness. The rough set theory (RST) was applied to determine the weights of the four main influencing factors as 0.2, 0.24, 0.36, and 0.2; furthermore, 19 groups of comprehensive values were calculated using the weighting method, and a water inrush risk assessment was conducted for several blocks within the working face. The results are presented as a contour map, highlighting various risk levels and identifying the water inrush danger zone on the coal seam floor. The study concludes that water inrush poses a threat in the western part of the working face, while the eastern area remains relatively safe. The accuracy and reliability of the model are demonstrated, providing a solid basis and guidance for predicting water inrush. Full article

Although the Internet grants access to a large amount of information, it is crucial to verify its reliability before relying on it. False information is a dangerous medium that poses a considerable threat, as it impacts individuals’ perceptions and information processing, eventually shaping people’s behaviors. Misinformation can be weaponized, especially in cross-border conflicts, where it can be used as a means to erode social cohesion by manipulating public opinion and exacerbate tensions between nations. Cognitive Warfare targets human cognition shaping to be a realm of warfare. It entails the synergy of activities designed to alter perceptions of reality, along with other Instruments of Power, to affect attitudes and behaviors by influencing, protecting, or disrupting cognition on an individual, group, or population level to gain an advantage over an opponent. The objective of our study was to identify behavioral patterns and profile personality traits most likely to accept fake news as true, aiming to mitigate the phenomenon and impact of misinformation and disinformation, as well as addressing the concerning effects of Cognitive Warfare. Based on the Big Five Theory model, we investigated the variation in visual attention and level of Conscientiousness, Open-Mindedness, and Emotional Stability in regard to the capability to detect fake news. In this study, we measured Implicit reaction time (IRT) and visual behavior (Eye Tracker) while participants were shown both fake and real news. The results indicated that subjects who were able to differentiate between fake news and real news tended to exhibit lower levels of Open-Mindedness and focused heavily on the visual elements of the posts. Full article

Kaijū media frequently features dangerous scientific experiments as a central theme, invented by scientists who are falsely convinced that they both completely understand and control their advanced technology. In the past few decades, this has included the introduction of high-energy physics (HEP) experiments—especially mammoth particle accelerators—that, among other destructive results, allow for the entrance of equally large and dangerous creatures into our world from parallel dimensions. Public concerns voiced about the safety of the creation of two groundbreaking energy accelerators—the Relativistic Heavy Ion Collider (RHIC) in New York and the Large Hadron Collider (LHC) in Europe—in the early 21st century are tied to related science fiction media that capitalize on such fears (including Godzilla vs. Megaguirus [2000], Pacific Rim [2013], The Cloverfield Paradox [2018], The Kaiju Preservation Society [2022]). Particular attention is paid to the Netflix original series Stranger Things (2016–) as a detailed case study. This study concludes with an analysis of scientists’ attempts to embrace the popularity of Stranger Things in their communication with the general public, and suggests that ongoing issues with conspiracy theories have been fueled in part by such attempts, coupled with long-standing issues with the HEP community and their peculiar scientific naming conventions. Full article

To enhance the risk management capacity of petrochemical enterprises, this paper presents a systematic and in-depth study of risk hierarchical control and hidden danger investigation technologies. Firstly, a risk hierarchical control system was developed based on text mining and Risk Breakdown Structure (RBS) theory, categorizing risk alarm levels into four tiers: no alarm, light alarm, medium alarm, and heavy alarm. Secondly, a hidden danger investigation and management system was established by integrating a three-dimensional hidden danger grading model with the Plan-Do-Check-Act (PDCA) closed-loop principle. Finally, a cooperative management technology system for risk and hidden dangers in petrochemical enterprises was constructed and validated using Shandong Luqing Petrochemical Enterprise as a case study. The results indicated that the comprehensive risk level of Shandong Luqing Petrochemical Enterprise is classified as II, with a yellow light warning signal. They demonstrated a positive correlation between the risk hierarchical control system and the hidden danger investigation and management system. The findings of this research provide valuable guidance for improving safety management in petrochemical enterprises. Full article

Due to the flammable and explosive nature of explosives, there are significant potential hazards and risks during transportation. During the operation of explosive transport vehicles, there are often situations where the vehicles around them approach or change lanes abnormally, resulting in insufficient avoidance and collision, leading to serious consequences such as explosions and fires. Therefore, in response to the above issues, this article has developed an explosive transport vehicle driving warning system based on object detection algorithms. Consumer-level cameras are flexibly arranged around the vehicle body to monitor surrounding vehicles. Using the YOLOv4 object detection algorithm to identify and distance surrounding vehicles, using a game theory-based cellular automaton model to simulate the actual operation of vehicles, simulating the driver’s decision-making behavior when encountering other vehicles approaching or changing lanes abnormally during actual driving. The cellular automaton model was used to simulate two scenarios of explosive transport vehicles equipped with and without warning systems. The results show that when explosive transport vehicles encounter the above-mentioned dangerous situations, the warning system can timely issue warnings, remind drivers to make decisions, avoid risks, ensure the safety of vehicle operation, and verify the effectiveness of the warning system. Full article