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In traditional construction safety assessment, it is difficult to describe the safety status of different construction stages. To solve this problem, this paper proposes a digital twin modeling theory for construction safety assessment. Firstly, this paper analyzes the requirements of a digital twin model. Secondly, the required information is collected by IoT. Finally, the DT model is established based on the collected information. This DT model analyzes the collected information by ML, which aims to conducting the assessments of construction safety. To verify this method, this paper analyzes the vault settlement during tunnel construction. The analysis results show that the DT model can predict the settlement value with high accuracy. Moreover, the safety state is assessed dynamically based on the settlement value by DT. [ABSTRACT FROM AUTHOR]

In nonclinical safety studies for new drug development, healthy animals have been commonly used. However, in some cases, the use of animal models of human disease is considered to be more favorable in evaluating risks in patients. To elucidate the current status of the use of animal models for nonclinical safety assessment, an internal questionnaire from the Japan Pharmaceutical Manufacturers Association and surveys (questionnaire period: August 27 to September 30, 2015) of both common technical documents and review reports of approved drugs (approval period: May 1999 to May 2017) disclosed by the Pharmaceutical and Medical Devices Agency were conducted. Although there were some concerns and limitations raised, the survey results revealed that animal models have been used in nonclinical safety assessment on a case-by-case basis and that nonclinical safety studies using animal models were included in the data packages of several approved drugs in Japan. The survey results also revealed that nonclinical safety studies using animal models have become more frequent in the past few years. In almost all cases, useful information, such as signs of toxicity under disease conditions and mechanisms of toxic change, was obtained from the results of nonclinical studies using animal models. Note: This is an opinion article submitted to the Toxicologic Pathology Forum. It represents the views of the author(s). It does not constitute an official position of the Society of Toxicologic Pathology, British Society of Toxicological Pathology, or European Society of Toxicologic Pathology, and the views expressed might not reflect the best practices recommended by these Societies. This article should not be construed to represent the policies, positions, or opinions of their respective organizations, employers, or regulatory agencies. [ABSTRACT FROM AUTHOR]

Safety (“biocompatibility”) assessment of medical devices has evolved along a different path than that of drugs, being historically governed more by the considerations and needs of engineers rather than chemists and biologists. As a result, the involvement of veterinary pathologists has been much more limited—almost entirely to evaluating tissue responses in tissues in direct contact with implanted devices. As devices have become more complex in composition, structure, placement, and use, concerns as to adverse systemic responses in patients have called for more comprehensive and thoughtful evaluations of effects throughout the body. Further complexities arise from the increasing marriage of devices and drug/biologic therapeutics to achieve either better dose control and, specifically, in delivery to target organs/tissues or better tolerance of the body to medical devices (i.e., minimization of the foreign body response). The challenge to pathologists is to integrate in new technologies (such as in vivo imaging and immunology) and ways of viewing interactions with patient bodies. To fail to do so will allow the methods and standards for medical device safety evaluation to be based on chemical analysis and then the limited details inherent in literature-based risk assessments. [ABSTRACT FROM AUTHOR]

The objective of the present research work was to explore the nutritional composition of different infant formulas and determine the safety status of these products. For this purpose, different infant formula brands were procured from the local market of Faisalabad, Pakistan. After the collection of these different brands, nutritional composition, i.e. fat, protein, ash, moisture and fiber was determined whilst the microbial analysis, such as Salmonella, Yeasts and Molds Count, and Total Bacteria Count, was carried out through their methods. In addition, the amino acid profile was assessed through paper chromatography. Furthermore, an appropriate statistical design was carried out to determine the level of significance. Mean values for amino acids, i.e. lysine, valine and cysteine varied from 3.06 g/100 g to 6.63 g/100 g, 4.90 g/100 g to 6.51 g/100 g, and 2.32 g/100 g to 3.04 g/100 g, respectively, in different brands of infant formula. Moreover, moisture content, crude proteins, crude fat, crude fiber, ash content, and nitrogen-free extract (NFE) varied from 1.6% to 3.83%, 10.55% to 14.67%, 9.82% to 26.63%, 1.00% to 4.13%, 1.87% to 4.20%, and 51.03% to 69.17%, respectively. It is evident from the microbiological analyses that Salmonella was not present in any brand of infant formula. Whereas yeast and mold counts were ≤2 cfu/g to ≤10 cfu/g in different brands. Moreover, total bacteria count was exhibited in the range of 1.5 × 103cfu/g to 6.3 × 103 cfu/g among different brands. Local infant formulas contained high amounts of heavy metals, i.e. 0.99 pp, of lead content followed by cadmium and aluminum as 0.28–0.98 ppm and 1.48–2.05 ppm, respectively. Conclusively, it is evident from whole research that local brands contained higher contents of heavy metal as compared to branded. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach to assessing structural safety, specifically aimed at evaluating the safety of existing structures. Firstly, a point cloud model of the existing commercial complex was captured utilizing three-dimensional (3D) laser scanning technology. Subsequently, an intelligent method for identifying holes within the point cloud model was proposed, built upon a YOLO v5-based framework, to ascertain the dimensions and locations of holes within the commercial complex. Secondly, Poisson surface reconstruction, coupled with partially self-developed algorithms, was employed to reconstruct the surface of the structure, facilitating the three-dimensional geometric reconstruction of the commercial complex. Lastly, a finite element model of the framed structure with holes was established using the reconstructed 3D model, and a safety analysis was conducted. The research findings reveal that the YOLO v5-based intelligent hole identification method significantly enhances the level of intelligence in point cloud data processing, reducing manual intervention time and boosting operational efficiency. Furthermore, through Poisson surface reconstruction and the self-developed algorithms, we have successfully achieved automated surface reconstruction, where the resulting geometric model accurately reflects the dimensional information of the commercial complex. Additionally, the maximum uniformly distributed surface load that the floor slabs within the framed structure with holes can withstand should not exceed 17.7 kN/m2, and its vertical deformation resistance stiffness is approximately 71.6% of that of a frame without holes. [ABSTRACT FROM AUTHOR]

This paper describes the safety assessment conducted in SESAR2020 project PJ.10-W2-96 ASR on automatic speech recognition (ASR) technology implemented for air traffic control (ATC) centers. ASR already now enables the automatic recognition of aircraft callsigns and various ATC commands including command types based on controller–pilot voice communications for presentation at the controller working position. The presented safety assessment process consists of defining design requirements for ASR technology application in normal, abnormal, and degraded modes of ATC operations. A total of eight functional hazards were identified based on the analysis of four use cases. The safety assessment was supported by top-down and bottom-up modelling and analysis of the causes of hazards to derive system design requirements for the purposes of mitigating the hazards. Assessment of achieving the specified design requirements was supported by evidence generated from two real-time simulations with pre-industrial ASR prototypes in approach and en-route operational environments. The simulations, focusing especially on the safety aspects of ASR application, also validated the hypotheses that ASR reduces controllers' workload and increases situational awareness. The missing validation element, i.e., an analysis of the safety effects of ASR in ATC, is the focus of this paper. As a result of the safety assessment activities, mitigations were derived for each hazard, demonstrating that the use of ASR does not increase safety risks and is, therefore, ready for industrialization. [ABSTRACT FROM AUTHOR]

In order to propose a reliable method for assessing the safety condition for single-tower steel box girder Suspension bridges over the sea, a condition monitoring system is established by installing sensors on the bridge structure. The system is capable of gathering monitoring data that influence the safety status of the bridge. These include cable tension, load on the main tower and pylon, bearing displacement, wind direction, wind speed, and ambient temperature and humidity. Furthermore, an improved Analytic Hierarchy Process (AHP) algorithm is developed by integrating a hybrid triangular fuzzy number logic structure. This improvement, coupled with comprehensive fuzzy evaluation methods, improves the consistency, weight determination, and security evaluation capabilities of the AHP algorithm. Finally, taking the No.2 Channel Bridge as an example and based on the data collected by the health monitoring system, the application of the safety assessment method proposed in this paper provides favorable results in evaluating the overall safety status of the bridge in practical engineering applications. This provides a basis for management decisions by bridge maintenance departments. This project confirms that the research results can provide a reliable method for assessing the security status of relevant areas. [ABSTRACT FROM AUTHOR]

With the rapid development of the mobile communication technology, the design of mobile phones has become more complex, and research on the electromagnetic radiation from mobile phones that reaches the human head has become important. Therefore, first of all, a model of mobile phone daily use was established. Then, based on the established simulation model, the safety of human head exposure to mobile phones was evaluated. The generalized polynomial chaos (gPC) method was used to establish a proxy model of the specific absorption rate (SAR) of the human head at different frequencies to perform a parameter uncertainty quantification (UQ). Finally, the Sobol method was used to quantify the influence of relevant variables on the SAR. The simulation results showed that the gPC method can save time and cost while ensuring accuracy, and the SAR value is greatly influenced by the electromagnetic materials of the mobile phone shell. Combined with the above analysis, this paper can provide reasonable suggestions for the design of mobile phone electromagnetic materials. [ABSTRACT FROM AUTHOR]

The radial gate corbel beam is a kind of gate support structure more often used in large and medium-sized reservoirs, but the current corresponding structural design code does not give a review calculation method for it. Because there are obvious differences between a corbel and a corbel beam in structural form and force, if the corbel beam is just simplified in the calculation as a corbel structure, it can easily lead to misjudgment of insufficient bearing capacity. This misjudgment has a significant impact on later safety assessment, danger removal, and reinforcement. Currently, there are limited studies available on the internal stress distribution of the corbel beam. In this study, taking the danger removal and reinforcement of the radial gate beam of a medium reservoir in Beijing as an example, the concrete quality of the dam was tested by the core drilling method, and two safety review methods of the corbel beam for different types of reservoirs were proposed in combination with the Code for Design of Hydraulic Concrete Structures (SL191-2008). Then, three different types of calculation model were established by the method of theoretical mechanics calculation and finite element simulation. Combined with the safety test data, the stress state of the combined stress structure of the corbel beam and gate pier under the real state was analyzed and the safety evaluation was carried out. The calculation results of these two corbel beam safety review methods were respectively reduced by 32% and 47% compared with the current calculation method. Engineering practice has proved the rationality of the two safety evaluation methods proposed in this paper, which can provide a certain reference for similar engineering reinforcement. [ABSTRACT FROM AUTHOR]

In recent years, the demand for medium and large secondary batteries in EV (electric vehicle) and ESS (energy storage systems) applications has been rapidly increasing worldwide, and accordingly, the market size is increasing exponentially. However, the recent fire accidents related to secondary batteries for EVs and ESS are having a negative impact on the battery market. Therefore, this paper implements an accident simulation device to perform an external short-circuit test, one of the typical safety tests for NMC-series prismatic and pouch-type batteries that are widely used among battery cells used in medium and large secondary batteries. The implemented accident simulation device for the external short-circuit test is composed of short-circuit resistance, measuring device, control device, etc., and is configured to analyze external short-circuit characteristics according to various test conditions. Based on this, an external short-circuit test according to the type, short-circuit resistance and SOC (states of charge) of the lithium-ion battery was performed to confirm the current and temperature characteristics according to each condition. As a result of performing an external short-circuit test for each protection device in the battery module and preprocessing temperature, it is certain that the module fuse operates over 120 times faster than the cell fuse based on the same SOC conditions, and the quantity of electric charge in the module fuse is over 110 times smaller than of the cell fuse in the case of a short-circuit fault. It is also found that the highest and lowest preprocessing temperatures are considered to be severe conditions. Based on the proposed mechanism of an external short circuit in a Li-ion battery and the test device for the external short circuit, it is confirmed that this paper can contribute to the safety assessment of Li-ion battery-based ESS. [ABSTRACT FROM AUTHOR]

This paper aims to study the dynamic response and damage of airtight protective doors of nuclear power plants subjected to tornado and wind-borne missile impact. Firstly, a safety performance evaluation method is proposed, considering the structural characteristics of the airtight protective door and relying on support rotation and airtightness. Then, the commercial finite element (FE) program LS-DYNA is utilized to perform the numerical simulations of airtight protective doors in nuclear power plants exposed to tornadoes and wind-borne missile impacts. Subsequently, the parameter analysis method is employed to investigate the impact of keel quantity, size and arrangement, door panel thickness, door core material, and boundary conditions on the dynamic response, airtightness, and failure mode of the airtight protective door. The results show that tornado wind pressure has little effect on the resistance of airtight protective doors and that the impact load of wind-borne missiles plays a leading role. The number and thickness of the keel have significant effects on the force transfer mode and failure mode of airtight protective doors. The thickness of the door panel has a great influence on the damage mode and airtightness of airtight protective doors. The door core improves the local resistance of the airtight protective door to a certain extent, and foam aluminum material has a better energy absorption effect. The change in boundary conditions has little influence on the resistance of airtight protective doors. [ABSTRACT FROM AUTHOR]

The concrete-filled steel tubular (CFST) arch bridge has achieved significant development in recent years due to its unique mechanical performance and technical advantages. However, due to the lagging theoretical research compared to engineering practice, many problems have been exposed in the existing bridges, resulting in adverse social impacts and enormous economic losses. With the increasing prominence of safety issues in CFST arch bridges, it is necessary to assess their safety condition in service. This paper establishes a safety assessment index system for CFST arch bridges using the fuzzy analytic hierarchy process (AHP) based on an exponential scale. The assessment method proposed includes the following main points: (1) Bridge safety assessment is closely related to the load-bearing capacity of components. This study proposes an assessment index that comprehensively considers both the defect conditions and the design load-bearing capacity of components for the safety assessment. (2) The exponential scale method is introduced to safety assessment for the first time, and the AHP based on an exponential scale is applied to calculate the component weights. (3) Considering the specific structural characteristics of CFST arch bridges, this study provides a detailed division of component types and calculates the component weights. By combining the component assessment indexes, a comprehensive safety assessment index system is established, and a safety assessment method for CFST arch bridges is proposed. (4) Taking the Jiantiao Bridge in Zhejiang Province as an engineering case, the load-bearing capacity of components is calculated using finite element software ANSYS 19.1. Based on the established safety assessment index system, the safety of the bridge is assessed by integrating the inspection results. (5) Software for the safety assessment of a CFST arch bridge is developed using Visual Basic, and the assessment results align well with the actual condition of the bridge. [ABSTRACT FROM AUTHOR]

With the rapid development of the construction industry, there have been an uncountable number of damages caused by safety accidents at construction sites. Traditional safety management methods are no longer able to meet the needs of production. This paper presents the concept of constructing safety management scenarios for construction engineering sites. Using a production base project as a research case, it analyzes the natural and human factors involved in constructing spatial–temporal scenarios at construction sites. By employing a spatial–temporal overlay method to analyze multiple safety assessment indicators, a spatial–temporal safety management scenario for the production base project is established. Subsequently, BIM and GIS technologies are applied to perform a spatial–temporal simulation of the construction site safety management scenario. This process delineates safety and hazard areas across different construction phases based on time and spatial dimensions, enabling a comprehensive safety assessment of the construction site of the production base project. The study offers a reference and guidance for improving the level of safety management at construction project sites. [ABSTRACT FROM AUTHOR]

Due to the rapid progress in the development of automated vehicles over the last decade, their market entry is getting closer. One of the remaining challenges is the safety assessment and type approval of automated vehicles, as conventional testing in the real world would involve an unmanageable mileage. Scenario-based testing using simulation is a promising candidate for overcoming this approval trap. Although the research community has recognized the importance of safeguarding in recent years, the quality of simulation models is rarely taken into account. Without investigating the errors and uncertainties of models, virtual statements about vehicle safety are meaningless. This paper describes a whole process combining model validation and safety assessment. It is demonstrated by means of an actual type-approval regulation that deals with the safety assessment of lane-keeping systems. Based on a thorough analysis of the current state-of-the-art, this paper introduces two approaches for selecting test scenarios. While the model validation scenarios are planned from scratch and focus on scenario coverage, the type-approval scenarios are extracted from measurement data based on a data-driven pipeline. The deviations between lane-keeping behavior in the real and virtual world are quantified using a statistical validation metric. They are then modeled using a regression technique and inferred from the validation experiments to the unseen virtual type-approval scenarios. Finally, this paper examines safety-critical lane crossings, taking into account the modeling errors. It demonstrates the potential of the virtual-based safeguarding process using exemplary simulations and real driving tests. [ABSTRACT FROM AUTHOR]

The paper deals with safety and reliability assessment as an integral part of the development process for modern aviation products with potentially critical functions. Focus is on digital engine control units, their development process and tools offering potential savings in otherwise time demanding and expensive safety assessment processes. The paper shows application of several approaches, which together form an innovative way for safety assessment of aerospace products (otherwise strictly limited by regulation procedures). It is focused on practical ways towards reduction of development costs during safety assessment, which do not compromise its comprehensiveness. Described approaches are based on experience from development of numerous aerospace products in last nearly 20 years. As an addition, possibility to further enhance the proposed innovative effect classification by application of FMECA was shown. Possible methods for quantitative assessment using Fuzzy logic and/or multiple-criteria decision analysis were discussed. [ABSTRACT FROM AUTHOR]

Probabilistic analysis based on random field (RF) has been widely adopted in the safety assessment of shield tunnels. However, its practical applicability has been limited by the intricacy involved with integrating geotechnical data and tunneling information. This paper addresses the following research question: How can the RF-based probabilistic safety assessment be carried out efficiently? In addressing this research question, we suggested an RF-based tunneling information modeling (TIM) framework to realize the probabilistic safety assessment of shield tunnels. In the proposed framework, the modeling of tunnel structure and geological conditions is initially introduced. The numerical safety assessment model is then created via an automated procedure using the RF-based TIM. A case study is conducted to verify the suggested framework, and results demonstrate that the framework can offer an automated design-to-analysis solution to improving the safety assessment of shield tunnels by comprehensively considering the uncertainties of geological conditions. [ABSTRACT FROM AUTHOR]

The emergence of Automated Driving Systems (ADSs) has transformed the landscape of safety assessment. ADSs, capable of controlling a vehicle without human intervention, represent a significant shift from traditional driver-centric approaches to vehicle safety. While traditional safety assessments rely on the assumption of a human driver in control, ADSs require a different approach that acknowledges the machine as the primary driver. Before market introduction, it is necessary to confirm the vehicle safety claimed by the manufacturer. The complexity of the systems necessitates a new comprehensive safety assessment that examines and validates the hazard identification and safety-by-design concepts and ensures that the ADS meets the relevant safety requirements throughout the vehicle lifecycle. The presented work aims to enhance the effectiveness of the assessment performed by a homologation service provider by using assessment templates based on refined requirement attributes that link to the operational design domain (ODD) and the use of Key Enabling Technologies (KETs), such as communication, positioning, and cybersecurity, in the implementation of ADSs. The refined requirement attributes can serve as safety-performance indicators to assist the evaluation of the design soundness of the ODD. The contributions of this paper are: (1) outlining a method for deriving assessment templates for use in future ADS assessments; (2) demonstrating the method by analysing three KETs with respect to such assessment templates; and (3) demonstrating the use of assessment templates on a use case, an unmanned (remotely assisted) truck in a limited ODD. By employing assessment templates tailored to the technology reliance of the identified use case, the evaluation process gained clarity through assessable attributes, assessment criteria, and functional scenarios linked to the ODD and KETs. [ABSTRACT FROM AUTHOR]

To reduce the environmental impact of aviation, aircraft manufacturers develop novel aircraft configurations and investigate advanced systems technologies. These new technologies are complex and characterized by electrical or hybrid-electric propulsion systems. Ensuring that these complex architectures are safe is paramount to enabling the certification and entry into service of new aircraft concepts. Emerging techniques in systems architecting, such as using model-based systems engineering (MBSE), help deal with such complexity. However, MBSE techniques are currently not integrated with the overall aircraft conceptual design, using automated multidisciplinary design analysis and optimization (MDAO) techniques. Current MDAO frameworks do not incorporate the various aspects of system safety assessment. The industry is increasingly interested in Model-Based Safety Assessment (MBSA) to improve the safety assessment process and give the safety engineer detailed insight into the failure characteristics of system components. This paper presents a comprehensive framework to introduce various aspects of safety assessment in conceptual design and MDAO, also considering downstream compatibility of the system architecting and safety assessment process. The presented methodology includes specific elements of the SAE ARP4761 safety assessment process and adapts them to the systems architecting process in conceptual design. The proposed framework also introduces a novel safety-based filtering approach for large system architecture design spaces. The framework's effectiveness is illustrated with examples from applications in recent collaborative research projects with industry and academia. The work presented in this paper contributes to increasing maturity in conceptual design studies and enables more innovation by opening the design space while considering safety upfront. [ABSTRACT FROM AUTHOR]

This paper aims at providing an overview of the most used injury criteria (IC) and injury metrics for the study of the passive safety of vehicles. In particular, the work is focused on the injury criteria that can be adopted when finite element simulations and Human Body Models (HBMs) are used. The HBMs will result in a fundamental instrument for studying the occupant's safety in Autonomous Vehicles (AVs) since they allow the analysis of a larger variety of configurations compared to the limitations related to the traditional experimental dummies. In this work, the most relevant IC are reported and classified based on the body segments. In particular, the head, the torso, the spine, the internal organs, and the lower limbs are here considered. The applicability of the injury metrics to the analyses carried out with the HBMs is also discussed. The paper offers a global overview of the injury assessment useful to choose the injury criteria for the study of vehicle passive safety. To this aim, tables of the presented criteria are also reported to provide the available metrics for the considered body damage. [ABSTRACT FROM AUTHOR]

The evolution of fracture zone controls the safety of underground coal gasification (UCG) in terms of gas emission and water leakage. In order to understand the fracture propagation in the confining rock of a UCG cavity with various influence factors, this paper implemented a set of numerical models based on different geological and operating conditions. Analysis was implemented on the mechanism of fracture propagation and its evolution characteristics, suggesting that (a) continuum expansion of the cavity leads a near-field fracture circle in confining rock initially, followed by the roof caving and successive propagation of shear band. (b) The key observed influence factors of fracture propagation are the grade of confining rock, overburden pressure, dimension of the cavity and gasifying pressure, the linear relationships between them, and the fracture height. Additionally, the fracture depth in the base board was mainly caused by tensile fracture. (c) A model was proposed based on the evolution of fracture height and depth in roof and base board, respectively. Validation of this model associated with orthogonal tests suggests a good capacity for predicting fracture distribution. This paper has significance in guiding the design of the gasifying operation and safety assessment of UCG cavities. [ABSTRACT FROM AUTHOR]

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The escape safety of passengers is the primary design requirement of cruise ships. However, larger and more complex structural schemes make the existing escape safety assessment methods insufficient to accurately calculate the safety index of the passengers' escape. Therefore, this paper proposes a novel assessment method to infer the passengers' escape safety index of large cruise ships. Firstly, on the basis of quantifying personnel attributes and moving speed, a confluence algorithm based on the dislocation accumulation model is proposed to correct the flow model of passenger escape. Subsequently, a passenger escape flow method based on the social force model is established. The proposed method is applied to the escape safety assessment of a 130,000-ton cruise ship. The validation of the results is conducted by a comparative analysis between the proposed method and the traditional method and the results of simulation tools. The comparison confirmed that the proposed method has merits in computing accurate results. Overall, the proposed method supports the safety design of cruise ships. [ABSTRACT FROM AUTHOR]

This paper presents a systematic investigation that encompasses the safety assessment of a fuel preparation room (FPR) intended for a hydrogen-fueled ship. The primary objective is to determine the appropriate ventilation strategy to mitigate the risks associated with potential hydrogen leakage. The study focuses on a case involving an FPR measuring 10.2 m × 5.3 m × 2.65 m, which is part of a 750 DWT hydrogen-powered fishing vessel. To identify the potential events leading to hydrogen dispersion, an event tree analysis is conducted. Additionally, existing regulations and guidelines related to the safety assessments of hydrogen leakage in enclosed areas are summarized and analyzed. Computational fluid dynamics, FLACS-CFD, are utilized for the consequence analysis in order to evaluate the impact of ventilation on hydrogen dispersion and concentration within the FPR. The research findings indicate significant effects of ventilation on the hazards and safety assessments of FPRs and high-pressure fuel gas supply systems. The study highlights that hydrogen vapor tends to accumulate at the ceiling and in the corners and spaces created by the equipment. The position and size of ventilation openings greatly influence the dispersion of hydrogen leakage. Proper ventilation design, including top inlet ventilation and outlet ventilation on the opposite side, helps to maintain a safe FPR by facilitating the efficient dispersion of hydrogen vapor. Moreover, locating inlet ventilation on the same side as the outlet ventilation is found to hinder dispersion, while the cross-ventilation achieved by placing inlets and outlets on opposite sides enhances airflow and dispersion. Consequently, it is recommended to prioritize the structural design of FPRs and implement enhanced safety measures. Additionally, updating the relevant regulations to address these concerns is strongly advised. [ABSTRACT FROM AUTHOR]

With the growing demand for transportation, there has been a significant increase in road-related projects, leading to potential risks in the safety of existing structures. This paper presents a study on the influence of new tunnel construction on the stability of an adjacent existing tunnel and provides valuable insights for the safety technology evaluation of similar tunnel crossing projects. In order to evaluate the influence of tunnel excavation on adjacent tunnels, the excavation process of a new tunnel near the original tunnel is simulated using the finite element software Midas GTS. This analysis includes the evaluation of static and dynamic responses. The results indicate that the horizontal and vertical displacements caused by the excavation of the railway tunnel are minimal. Furthermore, during the blasting excavation of the railway tunnel, the vibration velocity experienced by the highway tunnel remains below the safe allowable limit. These findings demonstrate that in this project, the influence of blasting excavation for the railway tunnel on the highway tunnel is both safe and manageable. [ABSTRACT FROM AUTHOR]

Featured Application: This study is based on the successful salvage of the Korean "Sewol" ferry in 2017. The approach delineated in the manuscript—the arrangement of two lifting barges in symmetrical disposition to retrieve a large-tonnage shipwreck—is increasingly being employed. The manuscript expounds the dynamic response of the salvage system and the technique employed to assess the safety of the system. Moreover, the manuscript articulates technical details, such as selecting the appropriate wave direction interval before initiating the salvage operation, selecting suitable intership connecting cables, and analyzing potential risks arising after the failure of the lifting cables. These elucidations can proffer insights to salvage engineers for optimizing design schemes. The International Maritime Organization (IMO) emphasizes that shipwreck accidents frequently occur at sea and advocates for the safe recovery of shipwrecks. This paper examines the case of the Korean "Sewol" ferry salvage, where two lifting barges were symmetrically utilized to retrieve a substantial shipwreck. The dynamic analysis of the salvage operation is based on the computational fluid dynamics (CFD) approach. The main investigation covers two fundamental physical parameters: the motion response of the lifting barges and shipwreck and the tension response of the lifting cables. Using the parameters of the maximum absolute value (MA), root mean square (RMS), and coefficient of variation (CV), a unified criterion is established to quantitatively evaluate the safety of the salvage operation under different working conditions. The study demonstrates that by carefully considering the enhancement of safety and stability for the three vessels involved in the salvage process and by optimizing the safety performance of the lifting cables, suitable operating windows are determined at wave intervals of (115°, 155°) and (205°, 245°). Under most working conditions, curves illustrating the maximum tensions of lifting cables No. 1–15 and No. 16–30 show a distribution with a "middle part drooping" shape. The placement of connecting cables on the water's surface at 1.1–1.2 times the salvage spacing between the two lifting barges or the arrangement of inclined lifting cables underwater proves advantageous in constraining the motion response of the three vessels. Reinforcing the lifting cables at the bow and stern ends is recommended. This study presents a methodology for salvaging a shipwreck using two lifting barges, which can be used as a reference for designing related salvage approaches. [ABSTRACT FROM AUTHOR]

This paper focuses on reviewing past progress in the advancement of definitions, methods, and models for safety analysis and assessment of process industrial systems and highlighting the main research topics. Based on the analysis of the knowledge with respect to process safety, the review covers the fact that the entire system does not have the ability to produce casualties, health deterioration, and other accidents, which ultimately cause human life threats and health damage. And, according to the comparison between safety and reliability, when a system is in an unreliable state, it must be in an unsafe state. Related works show that the main organizations and regulations are developed and grouped together, and these are also outlined in the literature. The progress and current research topics of the methods and models have been summarized and discussed in the analysis and assessment of safety for process industrial systems, which mainly illustrate that the dynamic operational safety assessment under the big data challenges will become the research direction, which will change the future study situation. [ABSTRACT FROM AUTHOR]

A safety instrumented system (SIS) is a complex unit composed of a set of hardware and software controls which are expressly used in critical process systems. A SIS should be specifically designed to obtain the failsafe state of the monitored plant or maintain safety of the procedure or a process when unacceptable or dangerous conditions occur. This paper focuses on condition monitoring and different diagnostic solutions used in safety instrumented systems, such as limit alarm trips, on-board diagnostics, and logic solver diagnostics. A case study consisting of the design of a safety loop using standard IEC 61508 for a complex safety instrumented system in the oil and gas field is presented in the paper using a diagnostics-oriented approach. The presented methodology aims at reaching the optimal tradeoff between IEC 61508 and the market requirements focusing on the best technological solutions to optimize diagnostics and safety and minimize the system's response time in case of failure. The results of the application emphasize the importance of an accurate diagnostic strategy on safety instrumented systems for oil and gas plants. [ABSTRACT FROM AUTHOR]

Hydraulic structures are typically subjected to long-term hydraulic loading, and concrete—the main material of structures—may suffer from cracking damage and seepage failure, which can threaten the safety of hydraulic structures. In order to assess the safety of hydraulic concrete structures and realize the accurate analysis of the whole failure process of hydraulic concrete structures under the coupling effect of seepage and stress, it is vital to comprehend the variation law of concrete permeability coefficients under complex stress states. In this paper, several concrete samples were prepared, designed for loading conditions of confining pressures and seepage pressures in the first stage, and axial pressures in the later stage, to carry out the permeability experiment of concrete materials under multi-axial loading, followed by the relationships between the permeability coefficients and axial strain, and the confining and seepage pressures were revealed accordingly. In addition, during the application of axial pressure, the whole process of seepage–stress coupling was divided into four stages, describing the permeability variation law of each stage and analyzing the causes of its formation. The exponential relationship between the permeability coefficient and volume strain was established, which can serve as a scientific basis for the determination of permeability coefficients in the analysis of the whole failure process of concrete seepage–stress coupling. Finally, this relationship formula was applied to numerical simulation to verify the applicability of the above experimental results in the numerical simulation analysis of concrete seepage–stress coupling. [ABSTRACT FROM AUTHOR]

The superstructure of a coastal bridge is prone to overturn or unseating under a catastrophic tsunami, which seriously affects the post-disaster emergency rescue. In this paper, we establish a safety assessment framework for the superstructure of a bridge with a box girder under a potential landslide tsunami, and apply it to an in-service box girder and Baiyun Slide Complex on the southeast coast of China. First, a meshless numerical approach called Tsunami Squares (TS) is used to predict the movement of landslides and tsunamis. Additionally, we introduce the velocity-weakening basal friction effect in the model to optimize the landslide dynamics. Second, the maximum lateral and vertical wave loads on a box girder can be estimated using the time series of the wave height and velocity in the TS model. Third, we construct a safety evaluation method for the superstructure using the reaction of the bearing as the critical index. The results indicate that the framework developed here provides instructive guidance for evaluating the safety of coastal bridge superstructures during tsunami disasters, and we discuss the influence of the basal friction effect, bridge elevation, and support type on the structural safety. [ABSTRACT FROM AUTHOR]

To explore the mixed traffic characteristics of vehicles and aircraft on the airport surface and solve the problem of real-time conflict detection at key intersections. According to the actual taxiing procedures and airport control rules in China, this paper focus on abstracting the mixed motion process of aircraft and vehicles in the maneuvering area, defining the convergent cross-safety operation scenario. To quantify the driver's attention to safety separation and the degree of conservatism in adjusting speed, the vehicle deceleration rate and acceleration rate are defined with α as the exponent. Under the same spacing, the vehicle deceleration rate is directly proportional to α, and α is named the vehicle safety sensitivity. At the same time, the rules of speed change of vehicles and aircraft will be designed, and a convergent operation model of aircraft and vehicles will be proposed. Based on real-time speed and separation dynamic assessment of safety and efficiency under different traffic strategies, the computer simulation results show that vehicle safety sensitivity and deceleration rules determine the sequence of vehicles and aircraft when they are passing through in the short term and can affect the proportion of mixed traffic flow in the long run. The safety probability of vehicles passing the intersection first is negatively correlated with vehicle safety sensitivity, while the safety probability of aircraft passing the intersection first is correlated positively with vehicle safety sensitivity. The efficiency of passing without conflict with mixed traffic has an inverse relationship with vehicle safety sensitivity. When the vehicle safety sensitivity takes the value in the interval [0.4, 0.6], a mixed traffic flow with higher safety and efficiency, better stability, and a balanced ratio of locomotives can be obtained. [ABSTRACT FROM AUTHOR]

• Asymmetry and leg-leg coupling exist in the planar dynamics models with the three-legged cushioning. • Two stage dynamics models reveal that the 2–1 landing allows the smaller safe initial attitude angle. • A favorable configuration of the three-legged LCM ensures the attitude angle safety margin of 23°. The probes landing on the surfaces of the asteroids can increase the scientific return of the exploration missions and also promote the development of deep space resources. Because of its excellent applicability to the uneven terrain and a lighter configuration than the four-legged mechanisms, the three-legged cushioning mechanisms are suitable for dissipating the impact energy and then quickly stabilizing the probe attitude when the probe lands on the micro-gravitational surfaces of the asteroids. Research on the landing dynamics of the probe facilitates to the design of the landing-cushioning mechanism and the optimization of its configuration, as well as the assessment of the landing safety. Comparing with the previous extensive related literature focusing on landing dynamics of the probes assisted by the four-legged cushioning mechanisms, this paper studies creatively the planar dynamics considering the asymmetric characteristic and the leg-leg coupling to understand the landing process of the asteroid probe with the three-legged cushioning mechanism and thereby to optimize the configuration of cushioning mechanism and assess safety margin of the landing. According to the touchdown status, the asymmetric landing modes are classified and the coupling issue in the construction of the landing models is explained. Consequently, two types of dynamics models describing the two-stages touchdown cushioning process of the probe are established. Then, five significant configuration factors of the cushioning mechanism are extracted, and their values combinations are designed according to the Taguchi orthogonal method. On this basis, the maximum safe landing attitude angles of the probe are solved by using these values combinations as the input conditions under the dangerous situations in different landing modes. The range analysis and nonlinear fitting methods are employed to discuss the influence of the configuration factors on the landing safety margin, and the favorable parameter values of the configuration factors are determined. Next, the influence of the ground obstacle on the landing safety margin and several methods to improve the margin are researched. Finally, the complete attitude changes of the probe in two representative landing cases are analyzed. The results studied in this paper can contribute to configuration optimization of the three-legged cushioning mechanisms and safety assessment of the legged probes landing on the asteroids, as well as to provide a reference for discussing the leg-leg coupling issue received less attention in landing dynamics of the probes with the four-legged cushioning mechanisms. [ABSTRACT FROM AUTHOR]

Robot online inspection is a new technology for nondestructive and quantitative detection corrosion of vertical storage tank without emptying the liquid. The storage tank safety assessment methods for robot online inspection are still at the exploratory stage of development. An online inspection robot has been developed by the authors. This paper studies the evaluation methods of bottom plate corrosion with this robot detection. Aiming to characterize localized corrosion and pitting corrosion, multi-angle evaluation indices are proposed. Mathematical models based on reliability evaluation are derived. Above models and evaluation methods are then validated by a case study. Assessment results show that the maximum corrosion depth of storage tank floor is 2.44 mm, the residual useful life of the storage tank is 5 years, and the center coordinates of localized corrosion region of numbered A is (0.58 m, − 0.01 m), the area is 0.484 m2, and the average corrosion depth is 2.03 mm. Abundant quantitative conclusions are obtained by using the proposed evaluation methods, instead of rough qualitative descriptions. This research provides references for storage tank safety assessments and formation standard based on robot online inspection. [ABSTRACT FROM AUTHOR]

The safety approval and assessment of automated driving systems (ADS) are becoming sophisticated and challenging tasks. Because the number of traffic scenarios is vast, it is essential to assess their criticality and extract the ones that present a safety risk. In this paper, we are proposing a novel method based on the time-to-react (TTR) measurement, which has advantages in considering avoidance possibilities. The method incorporates the concept of fictive vehicles and variable criticality thresholds (VCTs) to assess the overall scenario's criticality. By introducing variable thresholds, a criticality scale is defined and used for criticality calculation. Based on this scale, the presented method determines the criticality of the lanes adjacent to the ego vehicle. This is performed by placing fictive vehicles in the adjacent lanes, which represent copies of the ego. The effectiveness of the method is demonstrated in two highway scenarios, with and without trailing vehicles. Results show different criticality for the two scenarios. The overall criticality of the scenario with trailing vehicles is higher due to the decrease in avoidance possibilities for the ego vehicle. [ABSTRACT FROM AUTHOR]