Operational Safety Requirements Research Articles

Study of Urban Unmanned Aerial Vehicle Separation in Free Flight Based on Track Prediction

In recent years, the application prospect of urban logistics unmanned aerial vehicles has attracted extensive attention. The high-density operation of UAVs requires autonomous separation maintenance capability. To achieve autonomous separation maintenance, it is necessary to conduct autonomous track prediction and formulate the required separation accordingly. Based on the target level of safety requirements for UAV operation, aiming at the autonomous separation maintenance ability of UAVs and considering the accuracy of track prediction, a method to calculate the required separation between UAVs is proposed. This study consists of two parts. Firstly, based on historical data, the position prediction error of the flight track is investigated. Using a machine learning model, a two-stage track prediction method, which involves classification followed by prediction, is proposed for urban logistics UAV track data. Subsequently, based on the track prediction error distribution, by designing a gas model and a position error probability model, a separation-formulating model for urban logistics UAVs in free flight is proposed in which UAV maneuverability is considered. By applying this model, the required separation is formulated for UAVs. When the required separation is set to 48.5 m, the overall collision risk meets the TLS requirements. The research provides a feasible method for establishing autonomous separation for urban logistics UAVs.

Основные причины производственного травматизма при эксплуатации карьерного автотранспорта на золотодобывающих предприятиях Южной Якутии

Solid minerals mining is one of the main trends in the economic development of the Russian Federation. Mining dump truck transportation is an extremely essential component of the mining industry; in the coming decades, this transport will continue to be crucial for the transportation of overburden and minerals during open-pit mining in the course of the development of solid mineral deposits. Despite the numerous advantages of mining dump trucks, employment of this transport is one of the most hazardous technological processes in the Russian mining industry. More than one-third of all fatal accidents that have occurred in mining production can be associated with mining pump trucks. For example, the number of fatalities registered in certain areas of gold-mining enterprises of Southern Yakutia and associated with the operation of mining dump trucks can reach two cases per year. The goal of the study is to establish the main causes of industrial injuries during the operation of mining dump trucks employed by gold-mining enterprises of Southern Yakutia and the development of various measures to prevent such injuries. According to the results of conducted studies, accidents that occurred during the operation of mining dump trucks were caused by violations of safety rules and requirements in combination with human factors. To ensure the safe operation of mining dump trucks in gold-mining enterprises of Southern Yakutia, control over loading and speed of mining dump trucks should be strengthened; the process of repair job performance must be randomly checked on a regular basis; workers must regularly undergo tests for knowledge of safety rules and requirements for operation of mining dump trucks; and the material and technical base of the trucks must be upgraded. The suggested measures to minimize industrial injuries can be useful for both Russian and international mining companies that employ mining dump trucks.

Collaborative control of a levitation module for maglev trains with physical contact prevention and user-defined convergence time

The levitation module of maglev trains is contact-prone between electromagnets and guideways due to its high nonlinearity and various external disturbances. Hence, the coupling structure between the electromagnetic points in a levitation module calls for safe and collaborative control. To achieve this goal, this study proposes a novel collaborative levitation control scheme with physical contact prevention. Considering operational safety requirements confronted by the levitation system, a barrier function is introduced to address the physical contact problem, which strictly limits the levitation gap within an allowable range. Moreover, considering the transient response of the controlled system, the predefined-time stability is synthesised, which ensures that the tracking errors converge to a very small neighbourhood of zero within an arbitrarily settling time determined by users. This brings great convenience of tuning controller parameters and avoids non-trivial tuning with a large set of parameters by trails and errors. In addition, quadratic functions are integrated to guarantee the nonsingularity of control signals to enhance practicality. A series of numerical simulations verify the effectiveness of the proposed control scheme.

Increasing the Efficiency of Marine Engine Parametric Diagnostics Based on Analyses of Indicator Diagrams and Heat-Release Characteristics

In this article, we discuss the importance of the analysis of indicator diagrams and indicated parameters in operational diagnostics of marine engines. An innovative method was devised to improve the effectiveness of diagnostics based on this information. It consisted of the elimination of harmful measurement spaces during cylinder pressure measurements as well as an in-depth analysis of the resultant indicator diagrams based on the functions of heat release. This research demonstrated a negative impact on the quality of indicator diagrams and the values of the parameters indicated by cylinder pressure measurements with sensors mounted on indicator cocks. The elimination of the indicator cock and measuring channel in the cylinder pressure measurements affected the quality of the indicator diagrams and, based on the calculated heat-release functions, allowed the emergence of new (additional) diagnostic symptoms. This could significantly improve the effectiveness of diagnostics performed in operating conditions and, as a result, the effective, trouble-free, and ecological operation of marine engines, thus meeting the growing environmental and operational safety requirements.

Analysis of Facility Surveillance System by Tata Terminal Unit at Juwata Tarakan International Airport, North Kalimantan

The terminal is a liaison between land transportation and air transportation systems that accommodate all departure process activities from the transfer of passengers to goods. Passenger terminals must be able to accommodate operational activities and must meet operational security and safety requirements. In addition to taking part in the processing of existing activities, ensuring passenger comfort in using facilities is also important. Supervision of facilities can have a major impact on the safety and comfort of airport service users. The approach with qualitative methods is the approach that will be applied in this study. Qualitative research is research used to describe, explain, investigate, and find the quality of influence that cannot be explained, measured or described through a quantitative approach. The data obtained is in the form of research observations located at Juwata Tarakan International Airport, interviews with Tata Terminal Unit officers, and documentation. Data analysis techniques used include data collection, data reduction, and conclusions. The results of this study show that in supervising facilities at Juwata Tarakan International Airport there are still several obstacles experienced by Tata Terminal Unit officers, especially in terms of coordination and cooperation between Tata Terminal Unit and other units which are considered to have an impact on the satisfaction services provided at Juwata Tarakan International Airport.

Research Challenges for Energy-Efficient Computing in Automated Vehicles

Fully automated retail vehicles will have stringent, real-time operational safety, sensing, communication, inference, planning, and control requirements. Meeting them with existing technologies will impose prohibitive energy-provisioning and thermal management requirements. This article summarizes the research challenges facing the designers of computationally energy-efficient, economical, safe, and reliable automated retail vehicles.

Development of deep reinforcement learning-based fault diagnosis method for rotating machinery in nuclear power plants

Rotating machinery fault can cause accidents like loss of flow or turbine trip that seriously threaten the operation safety of nuclear power plants (NPPs). Artificial intelligence algorithms, like machine learning or deep learning methods, can implement fault diagnosis by sample learning with no reliance on fault mechanism or physics model of the equipment. However, the accumulated fault samples are small due to high operation safety requirements of the plant. Small sample learning is challenging and usually leads to degradation of model performance. The emerging deep reinforcement learning (DRL) algorithm can incorporate the advantages of automatic feature extraction from deep learning algorithm and interactive learning from reinforcement learning algorithm, is expected to have better learning ability and robustness. In this paper, two DRL fault diagnosis models are proposed and compared. Experiment results show that the proposed models can achieve very high diagnosis accuracy of over 99% and outperform all the baseline models (support vector machine, convolutional neural network and gated recurrent unit neural network) in all test cases in this paper.

Fire safety issues in underground spaces: a need for regulatory evolution – French, Swiss and Hong Kong SAR, China (Hong Kong) contexts

Current regulations and operational safety requirements impose onerous constraints that make it difficult to be fulfilled by practical design of underground projects acceptable to all stakeholders. The ACUUS working group on fire safety of underground spaces intends to gather and share information on the ways how fire safety is taken into account and managed in different countries. This article presents the first work carried out within this working group. Regulatory contexts in France, Switzerland and Hong Kong SAR, China (Hong Kong) are presented, highlighting the current limitations. With their similarities and differences, the French, Swiss and Hong Kong contexts reveal a need to improve and to develop their respective regulations to allow pragmatic solutions without compromising fire safety. Underlying principles that condition fire safety requirements are defined in order to develop new approaches to overcome the aforementioned limits.

PISTIL, a reactivity modulation device to probe the transfer function of the nuclear reactor CROCUS

The present article summarizes the development and testing of a reactivity modulation device developed by the French Atomic and Alternative Energies Commission (CEA). It was installed in the CROCUS reactor of the Swiss Federal Institute of Technology in Lausanne (EPFL). Experimental tests were performed in the framework of a collaboration between CEA and EPFL. The so-called PISTIL device aims at measuring the nuclear reactor transfer function in the frequency range of interest between 1 mHz and 200 Hz, in order to probe the in-core kinetic behavior of prompt and delayed neutrons. The reactivity modulation is obtained from the rotation of cadmium foils. The design of the system was driven with the objective of installing PISTIL at the center of the CROCUS reactor. Neutronic simulations with TRIPOLI-4 Monte Carlo code were performed to select the suitable design parameters and meet the safety requirements of the reactor operation. The total reactivity worth of the device, as estimated by TRIPOLI-4 Monte Carlo calculation, was approximately 0.16 $ and the maximum amplitude of the reactivity modulation was about 0.013 $. In-core reactivity calibration was then performed and were consistent as compared to TRIPOLI-4 estimations.

Analysis of single phase ground fault characteristics of low resistance ground active distribution network

A large number of distributed generators access to low resistance grounding system may have great influence on the fault characteristics of single phase ground. In view of low resistance ground active distribution network, the connection mode of Inverter-interfaced Distributed Generators (IIDG) is discussed comprehensively based on operation safety and protection requirements. The equivalent model of IIDG and simplified zero sequence network model of low resistance grounding system contain multi-IIDG for single phase ground fault are established. The amplitude and phase characteristics of zero sequence current in single phase grounding fault of the system and the characteristics of high-resistance ground fault are analyzed. Simulative results by MATLAB/Simulink verifies the correctness of the analysis results of fault characteristics. The conclusions could be provided as reference for solving the grounding protection of system with high penetration of distributed generator.

Performance Analysis of Prefabricated Steel‐Spring Floating‐Slab Track and Its Application to Urban Express Rail Transit

The aim of the research is the design of prefabricated steel‐spring floating‐slab track to be applied in urban express rail transit systems. Using a developed vehicle‐track dynamic‐coupling equation for steel‐spring floating‐slab track, the effects of length, thickness, vertical damping, and use of side‐mounted isolators on the floating‐slab track were investigated experimentally using full‐scale model and under different working conditions. The finding of the study revealed the following: (1) The prefabricated steel‐spring floating‐slab track can be applied to urban express rail transit, because it meets the requirements of high‐speed transit while efficiently reducing noise. (2) The floating‐slab track’s stability slightly increases with the increase of its length and thickness. As thickness increases, vertical displacement of the rail increases slightly, and lateral stability increases, thereby slightly improving the vehicle’s running stability. (3) When the intercity electric multiple‐unit train travels along the prefabricated steel‐spring floating‐slab‐track bed at different speeds, the wheel‐axle lateral force, wheel‐rail vertical force, the derailment coefficient, the wheel‐weight reduction rate, and the lateral acceleration of the vehicle body are all less than the specified limits of Chinese code, thus fully meeting the safety requirements of train operation. (4) Appropriately increasing the vertical‐support damping of the floating slab can improve the vehicle’s vertical dynamic performance, reduce the vertical displacement of the rail, and lower the vibration response of the floating slab. (5) Adding side‐mounted vibration isolators at the joint of the floating slab could greatly improve the stability of the floating slab itself and appropriately reduce the vehicle’s vertical vibration response. Due to the optimization and establishment of relevant factors influencing the performance of prefabricated steel‐string floating‐slab track achieved in the study, the results obtained are particularly useful for setting safety, comfort, and stability requirements of the floating slab.

Основные изменения требований промышленной безопасности к эксплуатации оборудования, работающего под избыточным давлением

Основные изменения требований промышленной безопасности к эксплуатации оборудования, работающего под избыточным давлением

Research on Optimal Operation Strategy of Multi-energy Power System Considering Complementary Coordination

Abstract Due to the obvious different characteristics of multi-energy power sources, it is necessary to take into account the economic and safety requirements of the power grid at the same time to achieve optimal operation strategy (OOS). This paper focuses on the OOS of multi-energy power system (MEPS), which contains wind power, cascade hydropower, thermal power, and pumped-storage power. Considering the complementary coordinationc characteristics of different types of energy, a completed set of day-ahead coordinated and optimized operating models of MEPS is established, with multiple optimization objectives of maximizing the safety, economy and renewable energy consumption. In order to solve this complex multi-objective problem, a three-stage solution method based on Benders decomposition is proposed. Through decoupling the safety object and economic object of MEPS, efficient solution of the OOS is achieved. The digital simulation discusses the influence of factors such as the diversity of natural scenarios and the safety requirements of the system operation, and simulation results verify the effectiveness of proposed strategy.

Temperature Monitoring and Flow Estimation in Electrolytic Cells Using Wireless Harsh Environment Sensors

Proper control of temperature and electrolyte circulation flow is mandatory in electrolytic cells to produce dense and high-purity cathodes. The electrochemical kinetics of cells is inherently dependent on these electrolyte variables. Continuous monitoring of electrolyte condition allows enhancing cathode quality, electrodeposition time, better utilization of electrolyte additives, early identification of temperature excursions, and electrolyte flow blockages. Abnormal cell conditions can produce excessive evaporation, higher energy consumption, anode passivation that impair cathode production in copper electrorefining, and safety issues because the production of flammable hydrogen in copper electrowinning. Therefore, the monitoring of changes in temperature and electrolyte flow can give critical indicators of process deviations. With real-time information about electrolyte variables, it is possible to provide early warnings to face the wide variability of cell performance and safety conditions caused by electrolyte condition mismanagement. This paper proposes a noninvasive wireless sensor for monitoring the electrolyte temperature inside cells and estimates the electrolyte circulation flow through each cell simultaneously. The sensor design is suitable to highly corrosive sulfuric acid environments. The condition-monitoring sensor proposed is small in size, lightweight, and meets battery-free operation and nonsparking safety requirements. It uses an inductive link-based system for powering and a radio frequency-link for communicating. The result is a sensor that surpasses the features of standard instrumentation not suitable for electrolytic process monitoring.

ＬＮＧバンカリングの手順と安全要件

ＬＮＧバンカリングの手順と安全要件

Isspresso Development and Operations

ABSTRACT The ISSpresso is a small aisle deployed payload developed to demonstrate the capability to brew quality espresso coffee in the environment found on the International Space Station (ISS) as well as in the conditions that would be experienced on possible future human exploration missions beyond Low Earth Orbit (LEO) to the Moon or Mars. A number of design challenges are presented by microgravity and low-gravity environments. In addition, the ISS program has a number of safety and interface requirements that any payload needs to adhere to. For ISSpresso each requirement was fully met as documented by the verifications submitted to NASA, including those required by the Payload Safety Review Panel (PSRP) to demonstrate compliance with ISS safety requirements for transportation, on-orbit operation, and return or disposal NASA Certification was obtained at the end of 2014. ISSpresso is currently onboard ISS having been successfully operated for the first time during Expedition 43.

Experimental research on applying the copper-clad aluminum tube as connecting tubes of air conditioners

This paper describes experimental investigation of copper-clad aluminum (CCA) tubing as a replacement for copper tubing to connect the indoor and outdoor units of split air conditioners. Experiments conducted on three specifications of CCA tubes (φ6.35×0.6mm2, φ9.52×0.7mm2, andφ12.7×0.8mm2) indicate good performance in terms of mechanical properties, processing properties, corrosion resistance, and pressure resistance; this means CCA tubes meet the installation and operation safety requirements for connecting tubes of air conditioners. Additionally, experimental results under two specifications – air conditioners in cooling and heating conditions – reveal no obvious difference in cooling or heating performance when CCA tubes, instead of copper tubes, connect the indoor and outdoor units of air conditioners. Furthermore, compared to copper tubes, CCA tubes can reduce the weight by 36.5%–46.3% and the material cost by 23.0%–34.8%. There is great potential for weight and cost reduction in the widespread application of CCA tubing as the connecting tubes in air conditioners.

A novel trajectory planning strategy for aircraft emergency landing using Gauss pseudospectral method

To improve the survivability during an emergency situation, an algorithm for aircraft forced landing trajectory planning is proposed. The method integrates damaged aircraft modelling and trajectory planning into an optimal control framework. In order to deal with the complex aircraft flight dynamics, a solving strategy based on Gauss pseudospetral method (GPM) is presented. A 3-DOF nonlinear mass-point model taking into account the wind is developed to approximate the aircraft flight dynamics after loss of thrust. The solution minimizes the forced landing duration, with respect to the constraints that translate the changed dynamics, flight envelope limitation and operational safety requirements. The GPM is used to convert the trajectory planning problem to a nonlinear programming problem (NLP), which is solved by sequential quadratic programming algorithm. Simulation results show that the proposed algorithm can generate the minimum-time forced landing trajectory in event of engine-out with high efficiency and precision.

Uniform hazard spectra in western Balkan Peninsula

Earthquake design codes, which are based on the performance-based design principles, aim to satisfy both the operational continuity and safety requirements for the designed structures. This calls for the design for at least two very different levels of strong earthquake shaking, and thus requires the amplitudes and the shapes of the elastic acceleration spectra to vary with geographic coordinates, and with the probabilities of exceedance. The traditional code procedures, which scale the design spectra in terms of peak ground acceleration and fixed shape spectra cannot meet these objectives. In this paper we show how the performance based design principles can be satisfied if the Uniform Hazard Spectral (UHS) method is used for scaling the design spectra. We illustrate this method for seismic zoning of the northwestern segment of the Bosnia and Herzegovina area, centered at Banja Luka in the Republic of Srpska. The method we present in this paper can be implemented in essentially all seismic regions of the world.

Turbomachine design choice for the gas-turbine cycle of NPP with HTGR

The most characteristic from the standpoint of turbomachine design reactor plants with HTGR and a closed gas-turbine cycle are briefly described. The operational particulars of an energy conversion system with single- and multishaft turbomachines in a closed gas-turbine cycle are examined. On the basis of an analysis of the particulars of single- and multishaft turbomachines, several variants of single-shaft turbomachines with rotational speeds 3000 and 4400 rpm and multishaft turbomachines with a high-rpm turbocompressor (6000 rpm) and turbogenerator with rotational speed 3000 rpm with a freewheel clutch or electric starting motor are presented. The effect of the configuration of the turbomachine on the static and dynamic parameters of the reactor facility in normal operating regimes and in emergency situations is analyzed. The present article analyzes a turbomachine design for the characteristic MGR-T (Russia) and PBMR (South Africa) projects in order to determine a rational configuration that secures high efficiency and satisfies operational reliability and safety requirements for the energy conversion system in a closed gas-turbine cycle with HTGR. The energy conversion system of a 600MW(t) MGR-T reactor includes a vertically oriented single-shaft turbomachine, recuperative heat exchanger, and water-cooled preliminary and intermediate coolers [1]. A single-shaft turbomachine on a full electromagnetic suspension consisting of a generator and turbocompressor made it possible to assemble an energy conversion system contained in a single sealed vessel, ensuring compactness and minimizing hydraulic losses in the first loop. However, the single-shaft high-capacity structure with rotation speed equal to the grid frequency (50 Hz) has a large number of compressor steps and, correspondingly, large rotor mass with blade systems. At the conceptual design stage of a 265 MW(t) PBWR reactor, a three-shaft design consisting of two vertical lowand high-pressure turbocompressors on electromagnetic bearings with rotational speeds 14200 and 15200 rpm, respectively, and a 3000 rpm turbogenerator were studied. The main plant equipment was placed in separate vertical vessels [2]. This turbomachine configuration decreased the rotor mass and, correspondingly, the load on the electromagnetic bearings, but the placement in separated vessels, connected by pipelines, increased the first-loop pressure limits and the hydraulic resistance. HTGR with Gas-Turbine Cycle. A setup with HTGR and a gas-turbine cycle must operate stably and efficiently at a 100% load in a prescribed range (from 15 to 100% N nom ) with speed to 10%/min and allow plant startup and shutdown. For reliable and safe operation during emergencies, it must be possible to reduce the load to the internal needs level, the admissible run-out revolutions of the turbomachine must not be exceeded in the event the generator is suddenly disconnected from the grid, it must be possible to maintain the rotation frequency of the turbomachine for a definite period of time and then restore it to the required level, and it must be possible to stop the reactor and turbomachine quickly and safely in the event of power loss and internal failures in the turbomachine and its systems.