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According to scientific studies dealing with the statistics of ICE (internal combustion engine) failures, most of them are registered in the ignition system (25%) and the power system (35%). The operable state of the ICE fuel system can be maintained by developing effective testing methods. For the purpose of theoretical research, a DBD-4 testing device was designed in the methodological part of the research. The use of the developed methodologies and instrumentation allowed carrying out experimental studies to diagnose the operability of the fuel supply system. Analyzing the obtained experimental data, it can be affirmed that: there is a stable relationship between the change in the ICE crankshaft speed and the change in the injection duration of the electromagnetic injector; the degree of wear of the electric fuel pump (EFP) is determined by the shift of the stable value of the crankshaft speed to the zone of low speed values at the same injection durations. The data obtained after testing the EFP allows planning a further algorithm of actions to maintain the operability of the fuel supply system.

Nano-electro-mechanical (NEMS) systems are compacted to be of dimension less than a micron by MEMS. Extremely high fundamental frequencies can be reached in this size regime while at the same time maintaining extremely elevated mechanical sensitivity (minute strength constant). This powerful mixture of attribute directly translate in to elevated strength sensitivities, ultra-low power operability's, and the capability to cause functional nonlinearities by very diffident controlling powers. Current paper addressed NEMS in this overview and will detail numerous of their stimulating original application. At the threshold for this new domain, however, there is a steep entry fee: modern innovation is key to realizing NEMS ' full potential. Some of the foundations of MEMS ' methods would obviously not usefully fit into the NEMS system. The main problem is the dimensions of the systems relative to the circuits in which they will be embedded, its excessive volume-to-surface ratio and its alternative “characteristic operating range.” These create some of the main challenges currently facing the development of NEMS. The majority of well-known of these is the requirement for: Very sensitive, elevated values of bandwidth dislocation transducer; unprecedented controls of quality of surface and adsorbents; new mode of capable Nano-scale actuations; and new surface as well as bulk Nano-machining approaches that are precise, robust and routinely reproducible.

Continuous ibuprofen (a widespread used analgesic drug) manufacturing is full of superiorities and is a fertile field both in industry and academia since it can not only effectively treat rheumatic and other chronic and painful diseases, but also shows great potential in dental diseases. As one of central elements of operability analysis, flexibility analysis is in charge of the quantitative assessment of the capability to guarantee the feasible operation in face of variations on uncertain parameters. In this paper, we focus on the flexibility index calculation for the continuous ibuprofen manufacturing process. We update existing state-of-the-art formulations, which traditionally lead to the max-max-max optimization problem, to approach the calculation of the flexibility index with a favorable manner. Advantages regarding the size of the mathematical model and the computational CPU time of the modified method are examined by four cases. In addition to identifying the flexibility index without any consideration of control variables, we also investigate the effects of different combinations of control variables on the flexibility property to reveal the benefits from taking recourse actions into account. Results from systematic investigations are expected to provide a solid basis for the further control system design and optimal operation of continuous ibuprofen manufacturing.

With the development of the aircraft gas turbine engine, a control system should be able to achieve effective thrust control to gain better operability. The main contribution of this paper is to develop a novel direct thrust control approach based on an improved model predictive control method through a strategy that reduces the dimension of control sequence. It can not only achieve normal direct thrust control tasks but also maximize the thrust level within the safe operation boundaries. Only the action of switching the objective functions is required to achieve the switch of these two thrust control modes while there is no modification to the control structure. Besides, a shorter control sequence is defined for multivariable control by updating only one control variable at every simulation time instant. Therefore, the time requirement for the solving process of the optimal control sequence is reduced. The proposed controller is implemented to a twin-spool engine. Simulations are conducted in the wide flight envelope, and results show that the average time-consumption can be reduced up to 65% in comparison with the standard model predictive control, and the thrust can be increased significantly when maximum thrust mode is implemented by using engine limit margins.

Quantum dot Cellular Automata (QCA) are a prominent nanotechnology that is widely employed in digital circuits and systems. In comparison to complementary metal–oxide semiconductor (CMOS) technology, QCA is a remarkable and challenging alternative with many attractive aspects such as fast execution and low power use. To accomplish all arithmetic processes, code converters are the fundamental unit of information change. Most of the converters, out of many designed for far in QCA, did not considered temperature stability, energy dissipation which may contribute to propagate as a non-operational circuit in various temperatures. This paper proposes a novel concept for a binary-to-gray code and a BCD-to-Excess 3 code converter based on QCA. The promised structure diminishes the number of cells, area utilized to make the design cost effective. The fundamental purpose of this research is to give a temperature stable and energy efficient converter design. The operability of the introduced design is verified with the QCADesigner2.0.3 tool and the temperature stability factor and energy waste are evaluated with QCADesignerE2.0.3.

Screen printing is regarded as a highly competitive manufacture technology for scalable and fast fabrication of printed microelectronics, owing to its advanced merits of low-cost, facile operability and scalability. However, its large-scale application in printed microelectronics is still limited by screen printing functional ink. In this review, we summarize the recent advances of ink formation, typical scalable applications, and challenging perspectives of screen printing for emerging printed microelectronics. Firstly, we introduce the major mechanism of screen printing and the formation of different organic- and aqueous-based inks by various solvents and binders. Next, we review the most widely used applications of screen printing technique in micro-batteries, micro-supercapacitors and micro-sensors, demonstrative of wide applicability. Finally, the perspectives and future challenges in the sight of screen printing are briefly discussed.

Accidents in chemical production usually result in fatal injuries, economic losses, and negative social impacts. To ensure personnel security in such cases, previous research has often used digital data, such as physical signals. However, the valuable textual information contained in chemical security texts, such as expert knowledge, has not yet been explored. Therefore, there is an increasing demand to mine useful information from these unstructured data. In this study, natural language processing (NLP) was applied to the hazard and operability (HAZOP) analysis reports. The classification model was trained to learn the classification of consequence severity levels in high-quality HAZOP analysis reports, which will not only ensure the consistency of the analysis results, but also help smaller chemical plants perform security analysis. In the classification model, we introduced Bidirectional Encoder Representation from Transformers (BERT), which, for word embedding, which is a powerful NLP pre-training model and significantly improved the effectiveness of the model. Through these application scenarios, the feasibility and possibility of applying NLP in chemical security text have been confirmed to a certain extent. In addition to digital data, future security managers will be able to monitor chemical production using natural language.

Complex cascading events might arise from the interaction between natural hazards and technological installations handling hazardous substances, leading to the so called Natech scenarios. Recent severe Natech events evidenced that the accident progression was initiated by the lack of operability of auxiliary systems and utilities available in the plant, and that the unavailability of safety systems in place was a key factor in accident development. These features of Natech scenarios are not captured by the current risk assessment procedures, which mainly focus on the release of hazardous substances caused by the structural damage of equipment. Starting from the lessons learnt from two complex Natech events, the Arkema accident and the Fukushima nuclear disaster, a paradigm shift towards a comprehensive assessment of Natech risk is proposed with the support of an innovative holistic framework addressing the identification and characterization of both “direct” Natech scenarios due to equipment damage, and of “indirect” Natech scenarios generated by the failure of auxiliary systems and utilities. The specific role of the modification of safety system performance during Natech events in the escalation of accident consequences is also addressed. Categories of hazardous substances having critical properties which may lead to major accidents in case of utility system failure were identified, in order to support the identification of “indirect” Natech scenarios. The specific methods and tools available to accomplish each step of the proposed framework are discussed, along with the main open issues and future research needs.

The present work presents an intervention proposal for the development of computational thinking in early childhood education, through the use of a ground robot with programmed directional controls. Within the use of observational methodology, an observation system has been designed that allows the analysis and interpretation of the behavior displayed in the performance of the intervention proposal. The reliability of the observation system has been guaranteed in the form of inter-observer agreement, calculated using Cohen’s (1960) Kappa coefficient. Within the theory of generalizability, the measurement plan [Categories] [Steps]/[Participants], has allowed to verify a high precision reliability of the generalization of the results. The operability of the observation system has been reflected in the regular behavior structures (T-patterns) detected -through the Theme software-, which have allowed characterizing difficulties in the assimilation of an incipient computational language related to the ability of spatial orientation and the sequencing capacity of children -situations involving turning and number of commands used in the sequence-.

Electrical energy storage (EES) systems consisting of multiple process components and containing intensive amounts of energy present inherent hazards coupled with high operational risks. Although the thermal hazards of batteries have aroused widespread attention, the safety issues of emerging large scale EES technologies persist. This study aims to begin to fill this gap by examining the hazards of typical 100 MWh or more EES systems which are used for grid applications. These systems include compressed and liquid air energy storage, CO2 energy storage, thermal storage in concentrating solar power plants, and Power-to-Gas. Hazard assessments are performed using a hybrid method to consider and evaluate the EES systems’ potential hazards from three novel aspects: storage, operability, and connectivity. Results reveal that for a similar energy storage capacity, cryogenic liquid systems have the least severe accident consequences while thermal energy storage using synthetic oil exhibits the largest. Concerning the operations in many cases, extreme operating conditions, complicated heat exchanger networks involving multiple flammable working fluids, and system operation intermittency present the major challenges to the safer operation of EES systems. Lastly, these systems themselves form one of many components of the power supply, each of which needs to accommodate fluctuations in supply and demand but also should be prevented from transmitting hazards to each other. Considering both engineering and administrative controls, this paper concludes with a discussion on the four grouped strategies from inherent to procedural for the elimination and mitigation of the identified hazards. Representative solutions and research perspectives including inherently safer design, operation uncertainty management, resilience analysis, energy barriers design, and life cycle safety assessment are suggested for the overall safety enhancement of industrial EES systems.

The availability of repair garage infrastructure for hydrogen fuel cell vehicles is becoming increasingly important for future industry growth. Ventilation requirements for hydrogen fuel cell vehicles can affect both retrofitted and purpose-built repair garages and the costs associated with these requirements can be significant. A hazard and operability (HAZOP) study was performed to identify risk-significant scenarios related to light-duty hydrogen vehicles in a repair garage. Detailed simulations and modeling were performed using appropriate computational tools to estimate the location, behavior, and severity of hydrogen release based on key HAZOP scenarios. This work compares current fire code requirements to an alternate ventilation strategy to further reduce potential hazardous conditions. Modeling shows that position, direction, and velocity of ventilation have a significant impact on the amount of instantaneous flammable mass in the domain.

This paper addresses the joint control problem in the context of a two-stage stochastic manufacturing/remanufacturing system, which involve both manufacturing and remanufacturing processes. Its operability is affected by frequent deterioration failures. Along with the condition of the system, the manufactured items are affected as well. Thus, the system obtains lesser revenues due to the low-quality products and the downtimes of the deteriorated system. For this purpose, the state and the condition of the systems and the manufactured products must be monitored dynamically so as to devise an optimal strategy for manufacturing, maintenance, and quality control. The present paper proposes a novel two-agent reinforcement learning framework that incorporates parametric production and maintenance activities. The aim is to improve the productivity of the system and keep the system operational with minimal maintenance activities so as to maximize the overall profitability. The performance of the presented approach is evaluated through experimental scenarios.

Rail passenger transport as the only mode of transport has the preconditions to form the essential axis of the integrated transport system and thus the basic framework of sustainable public passenger transport. In order to meet the preconditions, rail passenger transport must focus on research and innovation in the coming decades. Research and innovation must focus on these key areas: digitalisation and cost-effectiveness, automation of the railway system and Artificial Intelligence, sustainable and environmentally friendly solutions, intelligent RTV lifecycle management and enhancing RTV operability, integrating railways into the DOOR-TO- DOOR system (increasing the availability of rail transport services to customers) and security and protection (increasing customer safety and asset protection). Železnicna spolocnosť Slovensko, a.s., the national operator and the leader on the public transport market, aims at becoming a leader in research and innovation. ZSSK is currently implementing a number of projects related to these key areas. Within its strategy until 2030, ZSSK plans further activities in the key areas of research and development. The essential condition is the state support in the form of realization of the approved Strategic Transport Development Plan of the Slovak Republic until 2030 and elimination of the investment debt in the railway infrastructure and in the renewal and maintenance of RTV.

Improving the effectiveness and quality of maintenance and repair of road vehicles is one of the primary tasks in the Arctic zone of Russia. The paper analyzes international experience in solving these problems. It provides a description of a system ensuring the operability of buses with a division into subsystems. The marginal utility theory in conjunction with a system of maintenance and repair of motor vehicles is presented. The following relationships are addressed: the fleet utilization coefficient vs. the relative cost of production and technical facilities, the technical readiness coefficient of vehicles vs. the relative cost of production and technical facilities, the specific capital investments in production and technical facilities vs. the scale of the enterprise, the technical readiness coefficient and the consumption of spare parts vs. the mechanization level. In the course of the study, we considered the structure of the operational and repair cycle of vehicles. Besides, we compared the effectiveness of different options for improving the production and technical facilities of bus servicing. It was proved that one of the most important effectiveness indicators (vehicle utilization rate) reaches the maximum level with a rational combination of servicing centralization, specialization, and cooperation.

Due to the planned growth of transport construction in the North of Russia and the Arctic territories, the issues of ensuring machinery operation during such construction, including the organization of its maintenance and repair, become quite urgent. Transport construction, like other linear construction projects in the North, has a number of features that shall be taken into account when organizing repair. These features include low temperatures in winter that persist for long periods, poor transport accessibility, construction facilities scattered along the route under construction, remoteness from industrial centers, etc. To form a repair system that would ensure machinery operability and a high technical readiness coefficient, it is necessary to organize a system of repair shops performing current and restoring repairs, and in some cases, overhaul repairs, as well as maintenance facilities. The paper discusses the main directions of solving the problem related to the arrangement of repair facilities near construction sites. Since heavy excavation equipment is used in these conditions, a problem with its delivery for repair arises. In view of this, we present methods to calculate the demand for trailers servicing the repair system.

Computer Numerical Control Machine Tool (CNCMT) Digital Twin (DT) model is a carrier for complex, time-varying, coupled data of CNCMT, which can theoretically provide a time-varying high-fidelity model. However, there are still many difficulties in its implementation process. And the key issue is how to realize the updated DT model with performance attenuation and validate it. In order to solve this problem, a model consistency retention method for CNCMT DT model is studied and proposed in this paper. Firstly, the framework of consistency retention method for DT model is designed including both digital space and physical space. The principles of data management and performance attenuation update in digital space are elaborated. Then, the implementation method for consistency retention of CNCMT DT model is studied in terms of performance attenuation update workflow for wear and other damage separately. Finally, a case study for the establishment and application of high-fidelity test bench DT model that focusing on rolling guide-rail is carried out to show the implementation flow of the proposed method and verify its operability and effectiveness.

In Japan, deterioration of electric power supply systems has been accompanied by a steady increase in the quantity of maintenance work. Since such work on the bucket of an elevated work vehicle is extremely hard for the workers, innovations are required to save labor. Some robotic systems attached to the bucket have been researched, however, they are remotely operated and their operability is not so good. Therefore, we propose and develop a new assistive robotic arm that can be operated directly and easily by only one worker on the bucket. It is practical, easy to install, and relatively light weight. This system consists of three arms and each arm has 4 DOF and one semi-fixed joint. The arm end can be extended from the level of the operator's hands to a height of about 1 m above his head for safety work then retracted to replace one specialized tool with another. An operation grip is located near the arm base and the arm moves in direction the grip is pushed. This grip also equips smart mechanism for permitting the operator to sense the reaction force on the end tools. A prototype robotic arm was made and some operating tests were carried out to ensure the effectiveness of the proposed human-robot cooperation system.

This paper presents a new bending method of sheet metal for forming diversified shapes and enhancing operability. The method, “asymmetric bending”, uses a punch and a pair of front and back dies. While the punch moves down for bending, the two dies move at different velocities so that the movement of the front side of the sheet metal can severely be restricted. The front side of the metal can be deformed with diversity in advance as it can escape from geometric interference with the bending tools. The method also improves operability and safety for operators due to the movement restriction.

In order to achieve a good and competitive FPSO design, the building cost and the motion performances are the two most critical and conflicting KPIs to be considered. In this study, the author's previous work (Lee, et al., 2021) on the optimization of an FPSO's hull dimensions with 1800 MBBLs storage capacity at Brazil field was extended using a multi-objective parametric optimization with the hull steel weight and the operability which are closely related to the building cost and the operational cost during the lifetime, respectively. For the purpose of more realistic and practical FPSO design, the constraints related to crew comfort and the safe helicopter take-off and landing operation were newly added. Also, the green water on deck was calculated accurately to check the suitability of the designed freeboard height using a newly developed real-time calculation module for the relative wave elevations. With aids of this updated optimization formulation, we presented multiple optimal FPSO dimensions expressed as a Pareto set which aids FPSO designers to conveniently select the practical and competitive dimensions. The excellence of the developed approach was verified by comparing the optimization results with those of FPSOs dimensioned for operation at West Africa and Brazil field.

Multi-criteria Decision Making (MCDM) is widely used for problem-solving in various research fields and has shown good results in risk analysis as well. However, given the gaps found in previous studies in the context of risk analysis, this article proposes and conducts a novel MCDM-based HAZOP analysis: a hybrid methodology with an MCDM approach, Strategic Options Development and Analysis (SODA), and Intuitionistic Fuzzy Sets (IFS). We combine their advantages by using SODA with Intuitionistic Fuzzy Cognitive Maps and by reducing the inherent uncertainty and subjectivity of HAZOP with an IFS-based MCDM sorting algorithm. To demonstrate the usefulness and flexibility of this approach, a real application with a continuous pyrolysis system was conducted, and a comparative analysis was made of the main related studies to demonstrate the advantages of the approach now proposed. On applying it, 40 hazards were identified (seven more than a previous analysis conducted in 2016), and only 3 (7.5 %) of them required special attention. Among the positive points highlighted by the team, the most cited were the resource-saving, greater focus and objectivity, and a more realistic perception of hazards. In particular, we show that our methodology is more consistent and appropriate than those in previous related articles. To assist future users, we provide a framework for the application.

Many continuous industrial processes operate in different steady states with different grades or products. The switching between two steady states is called transition. Transition consists of a series of operation changes that should be carried out in proper order, within certain magnitudes and time region. Since faulty operation may lead to increase in inferior products or even hazard events, monitoring of the transition is desired. In this work, a transition identification and monitoring scheme is proposed based on slow feature analysis. Two monitoring statistics which represent the location of the trajectory and the speed of transition are proposed. Besides, operating faults are generated based on the guidewords of hazard and operability analysis (HAZOP). Using a numerical case and the mode 4-to-2 transition of the Tennessee-Eastman process in which catastrophic failures exist, the effectiveness of the proposed method is validated. In addition to missed detection rate and false alarm rate, two performance indexes known as detection time (DT) and rescue time (RT) are introduced. The advantages of proposed method are benchmarked against the stage-based sub principle component analysis(sub-PCA) and the global preserving statistics slow feature analysis(GSSFA).

Differential has been extensively applied in solving many engineering matters. The development of tourism destination with multiple scenic spots is a long-term systematic project and the existing decision-making methods are actually not suitable for this process. Thus it is necessary to introduce new decision-making method to analyse the investment process of tourism destination project. Specifically, considering the irreversibility and extendibility of destination development, the present paper constructed a differential dynamic decision-making model for the long-term investment project based on the classical model of real option; B-S model, and analysed the key parameters affecting the modified model; the present price of the project (ω) and the volatility (δ). An example analysis and a case from Yinziyan scenic area were further analysed to test the operability of the proposed model. The proposed model contributes to dealing with uncertainties and enhancing the decision quality of investors in the investment of scenic spots. And the application of differential in tourism destination development contributes to the accuracy of decision-making. Therefore, this paper has both theoretical and practical significance.

The marine access refineries which supply nearly 15% of the global energy requirement constantly encounter uncertainty such as unit unavailability. This uncertainty often arises due to various factors such as pump failure or leakage in tanks. Crude oil scheduling under such uncertain conditions not only compromises the profitability but also compromises the operability of the plant. The study comprehensively analyses the advantages and disadvantages of using preventive and reactive scheduling approaches to handle a commonly encountered tank unavailability uncertainty. Based on these, a new hybrid approach which combines both the features from the preventive and reactive approach is developed. This study is important for solving scheduling optimization problem when uncertainty, non-linearity and multiple objectives are involved. For this purpose, three large-scale marine access refinery scheduling problems having a time horizon of 7, 7 and 14 days were studied.

The hydrodynamic operability and the influence of fluid properties on hydrodynamics under supercritical conditions were investigated in a 38 mm diameter column packed with ¼” Dixon rings. The column was operated using 100 cSt and 200 cSt Poly[dimethylsiloxane] (PDMS), with supercritical CO2 at 14 MPa and 333 K, 328 K and 323 K respectively. The pressure drop, liquid hold-up, mass flow and mass fractions were measured. The column operability limits were determined for both systems over a range of liquid and supercritical fluid flow rates using the measured data. Three distinct types of inoperability were identified, namely liquid layer flooding, bubble column flooding and excessive entrainment. It was found that liquid hold-up and pressure drop are not reliable indicators of operability in supercritical systems. Further, no observable loading operating regime was found, with the column only operating in the pre-loading or inoperable (flooded/entrained) regimes. The influence of the density and dynamic viscosity on hydrodynamics was found to be complex, yet significant. Small changes in temperature caused substantial changes in fluid properties, having a significant impact on column operability. Column operability range reduced with an increase in liquid viscosity and SF density. Finally, the data are compared to available models.

Cost and durability remain the two major barriers to the widespread commercialization of polymer electrolyte membrane fuel cell (PEMFC)-based power systems, especially for the most impactful but challenging fuel cell electric vehicle (FCEV) application. Commercial FCEVs are now on the road; however, their PEMFC systems do not meet the cost targets established by the U.S. Department of Energy, primarily due to the high platinum loading needed on the cathode to achieve the requisite performance and lifetime. While the activities of a number of commercial Pt-based alloy cathode catalysts exceed the beginning-of-life (BOL) targets, these activities, and the overall cathode performance, degrade via a variety of mechanisms described herein. Degradation is mitigated in current FCEVs by utilizing a cathode catalyst with a lower BOL activity (e.g., much lower transition metal alloy content and larger BOL nanoparticle size), necessitating higher catalyst loadings, and through the utilization of system controls that avoid conditions known to exacerbate degradation processes, such as limiting the fuel cell stack voltage range. The design and development of active and robust materials and eliminating the need for vehicle mitigation strategies would greatly simplify the operating system, allowing for greater transient operation, avoiding large hybridization, and curtailing of fuel cell power. Although system mitigation strategies have provided the near-term pathway for FCEV commercialization, material-specific solutions are required to further reduce costs and improve operability and efficiency. Future material developments should focus on stabilization of the electrode structure and minimization of the catalyst particle susceptibility to dissolution caused by oxide formation and reduction over PEMFC cathode-relevant operating potentials plus minimization of support corrosion. Ex situ accelerated stress tests have provided insight into the processes responsible for material and performance degradation and will continue to provide useful information on the relative stability of materials and benchmarks for robust and stable materials-based solutions not requiring system mitigation strategies to achieve adequate lifetime.

Renewable power generation facilities are constantly expanding due to the expected depletion of fossil fuels and the increasingly demanding policy of pollution control. Having said that, hydrogen is one of the promising energy sources. That said, hydrogen chain safety is an unescapable parameter that should continuously coexist with the development of hydrogen domain. In this context, this article presents a contribution to the risk analysis and evaluation of a complex hydrogen production system 'EGA-9000′ at CIEMAT (Centre for Research on Energy, Environment and Technology - Madrid, Spain). The methodology followed in this study revolves around the risk analysis process through a FAST (Functional Analysis System Technique) functional analysis method and a HAZOP (HAZard and Operability) dysfunctional analysis method. The evaluation of the thirty-three scenarios identified by the risk analysis shows that the studied system is insecure. Indeed, five scenarios at an unacceptable level of risk. And it is noted that the risk of fire and explosion is the major risk for all scenarios studied. To this end, safety measures (recommendation) have been proposed based on the weaknesses detected by the risk analysis carried out.

The considered simulation tasks are based on an electrometallurgical process development strategy and associated telemanipulator simulation systems are proposed with various scales of experimental facilities. Fundamentally, target facilities are assumed to be operated only by remote handling systems because the considered process is operated in hazardous environments. Futhermore, the feasibility at various scales should be experimentally verified with gradual increase in throughput. In this regard, bench, engineering, and pilot-scale simulation systems are important early-stage tools for assessing the practical operability of the target process with the material handling systems. Such simulation systems are highly customized for applications and are a precursor to larger pilot and demonstration-scale plants. This paper introduced and classified the developed simulator systems for this approach at various scales using remote handling systems which were assembled inside a virtual target facility, and the man-machine interface was included for a more realistic operation of the simulator. The results obtained for each simulator show the feasibility and requirement for improvement of the systems for the considered test issues with respect to the operation and maintenance of the process. Keywords: Telemanipulator, Remote handling system, Autonomous teleoperation system, Hardware In the Loop Simulation (HILS), Virtual Reality (VR), Confined cell facility

This paper presents an investigation of hazard sources identification and reliability sensitivity analysis of CTCS-3 on-board subsystem. Traditional quantitative and qualitative safety and reliability analysis generally used static analysis methods, such as Fault Tree. When device redundancy, dynamic logic and dynamic mechanism are taken into consideration, dynamic analysis methods are preferred, such as Dynamic Fault Tree (DFT). In this paper, the methods of Hazards and Operability (HAZOP), DFT and Monte Carlo Simulation (MCS) are used for quantitative and qualitative analysis. Firstly, to reflect the structure and functions of on-board subsystem, two models (i.e reference model and function hierarchical model) are built. HAZOP is applied to identify hazard sources of on-board subsystem according to above models. Secondly, DFT is put forward within which the top event is CTCS-3 on-board subsystem failure event and the basic events are from results of HAZOP analysis. Then, both MCS and Maximum Likelihood Estimation (MLE) are adopted to estimate the reliability parameters of the CTCS-3 on-board subsystem and components. Reliability sensitivity analysis is observing the variations in components’ reliability parameter contributing to the changes of Mean Time to Failure (MTTF) of CTCS-3 on-board subsystem. Finally, a failure density curve of CTCS-3 on-board subsystem and a table of MTTF sensitivity parameters are presented. According to the sensitivity table, it is knowledgeable for decision makers to take effective measures to improve the reliability of CTCS-3 on-board subsystem.

Conventional HAZOP is a collaborative and multidisciplinary activity to identify the hazards associated to operability of the chemical processes. Then the consequences and required safeguards of each potential deviation or failure are assessed qualitatively one by one. It is performed with the assumption of "one failure at the time" for the process parameters. Furthermore, process complexities such as multiple failures, domino effects, time and amplitude dependent deviations etc. are avoided to keep the HAZOP brainstorming sessions systematic and effective. Therefore, the quality and outcomes of HAZOP study are relatively subjective and depend on the experience and competency of the HAZOP team. This simplified approach cannot fully cover the hazard identification and risk assessment of the complex processes such as polymerization. Furthermore, the incident investigations show that almost all major accidents have occurred due to multiple failures or domino effects. This paper aims at developing a practical methodology in the context of "Industry 4.0" and particularly illustrate how dynamic simulation liberates the HAZOP team from the simplification assumptions such as one failure at the time or neglecting the domino effects during the lifecycle of the complex processes. An industrial styrene bulk free radical polymerization process has been chosen as the case study to depict the applicability of the proposed method. In continuation of this research, the dynamic simulation integrated with Artificial Intelligence (AI) algorithms and Multivariable Process Monitoring (MPM) together with virtual collaboration tools will be invoked towards a more practical and effective HAZOP 4.0 platform. Such a platform can be the foundation of the further Process Safety Management (PSM) elements such as "Operating manuals", "Training and Competency management", "Condition monitoring and predictive maintenance", "Management of Change", "Pre-Start-up Safety Review", etc.

The importance of considering operability, control, and safety criteria in the analysis and design of process intensification configurations is discussed in this paper. We first rigorously analyze the loss of degrees of freedom and role of constraints in intensified systems comparing with their conventional process counterparts. A comparison study on inherent safety metrics in reactive distillation process is then presented to stress the need for new safety metrics at early design stage. To address these operability and safety challenges, we highlight a framework for systematic integration of operability, safety, and control to synthesize operable process intensification systems.

A complex kinetic model of damage development under cyclic loading is proposed to describe the process of fatigue failure. Two separate models are proposed. A numerical method for calculating crack-like zones up to macro fracture is proposed. The results of numerical fatigue experiments are presented. The operability of the single criterion model and calculation algorithm is shown on experimental results. The potential operability of the double criteria model was shown; the presence of two criteria that use different types of crack nucleation may result in cases when one of the criteria leads to crack growth while the other one does not and vice versa. Under a complex stress state in the proposed double criteria model the natural implementation of any of the considered crack development mechanisms is possible. Cracks of different types may be developing simultaneously in various parts of a specimen.

The cavity-based flameholder is a promising device in supersonic combustion issues in a scramjet engine and it also provides a favorable ignition environment inside the cavity owing to low speed recirculation flows and relatively high static temperature. The cavity ignition process as the beginning phase of the flameholding process is of vital importance to the performance of the scramjet engine and also operation safety of the aircraft. This paper reports recent research progress on the complex cavity ignition process in supersonic flows, which is summarized from five aspects, namely study on non-reacting flows regarding ignition, effect of ignition method, effect of igniter setups, effect of cavity fueling and effect of cavity geometry. Aspects of the non-reacting and reacting cavity flow fields prior to and during ignition process are discussed comprehensively with emphasis on the effects of above ignition influencing factors. In addition, typical ignition methods are introduced in detail and compared to describe the cavity ignition operability in real scramjet applications. Finally, some promising recommendations have also been proposed for the cavity ignition process.

In recent decades, a series of policies and practices for environmental flows (e-flows) have been implemented in China, with the sustainable development goal of balancing the utilization and protection of water resources among social, economic, and ecological needs. The aims of this study were to determine the main challenges and issues in e-flows implementation at different scales by analyzing policies and practices for e-flows in China, and to propose some recommendations for bridging the gaps between the science and implementation of e-flows. The gaps between the science and implementation of e-flows were found after review of literature, policies, and practices, and it was found that ecological flow was a more widely used term by the government, rather than e-flows, in implementation. The plans and effects of e-flows implementation are discussed in this paper and challenges of e-flows implementation are recognized: (1) limited water resources and uneven spatial and temporal distribution, (2) a weak scientific basis for e-flows implementation, (3) poor operability of e-flows science, and (4) ineffective supervision and guarantee measures. The recommendations are (1) to strengthen the scientific foundation of e-flows, (2) to improve effectiveness in application of e-flows science, and (3) to propose operable and effective supervision and guarantee measures. This paper elaborates the current understanding of e-flows science and provides practical recommendations for implementing e-flows and for improving the effectiveness in e-flows implementation. To bridge the gaps between science and implementation of e-flows and improve the operability of policies in future practices, more scientific research on practices is recommended through adaptive management. Keywords: Environmental flows, Ecological flow, Integrated water resources management, Adaptive management, Sustainable development

In this work, the optimal integration between an oil refinery and an ethylene production plant has been investigated. Both plants are connected using intermediate materials aiming to remove, at least partially, the reliance on external sourcing. This integration has been proven to be beneficial in terms of quality and profit increase for both production systems. Thus, three mathematical models have been formulated and implemented for each plant individually as well as for the integrated system as MINLP models aiming to optimise all three systems. Moreover, a case study using practical data is presented to verify the feasibility of the integration within an industrial environment. Promising results have been obtained demonstrating significant profit increase and enhanced operability in both plants.

This study aims at analyzing dynamic behavior for the full operation cycle considering various alternatives and constraints related to small-scale and seaborne environment for a BOG re-liquefaction process in LNG-fueled ships, leading to significant enhancement of its operability. The design framework includes steady-state modeling, dynamic modeling and control system, with which system-wide dynamic characteristics are readily investigated and operating guidelines for achieving optimal process operations are obtained. Equipment sizing with the appropriate choice of design parameters is made such that the dynamic model developed in this study simulates non-steady-state characteristics in a realistic manner. 8 different process control schemes are proposed, and their technical gains as well as dynamic characteristics are investigated in details. The control algorithms are assessed through controllability analysis, including open loop test, open loop disturbance test and dynamic response against disturbances. For improving process efficiency, operation procedure for shut-down and start-up is designed with constraints imposed such as rotating speed variation and inert material filling for the effective and practically-adequate control for a refrigeration cycle, with which feasible heat transfer can be readily maintained. The case study presented fully demonstrates the validity and applicability of the control system proposed in this study.

The paper deals with the formation of a list of critical facilities in Russia's gas transportation system in terms of energy security, and the substantiation of potential ways to minimize the negative effects of emergency situations on operation of these facilities. To date the lists of critical facilities in the energy systems have been formed on the basis of the performance analysis of certain facilities. The paper addresses the problem of identification of such facilities depending on their impact on overall operability of the system. This is accomplished by analyzing the level of negative impact caused by termination or disturbance of operation of a certain facility on consumers. The analysis employs the software “Russia's Oil and Gas” (“ROG”). The principles of identifying critical facilities in Russia's gas transportation system are demonstrated, specific examples are shown, and potential ways to mitigate the negative impact of emergency situations at such facilities on gas consumers are formulated.

In this paper, a transient model is developed to simulate the start-up operation of an industrial twin-shaft gas turbine based on real geometry and control logic. The components’ characteristic curves of the studied gas turbine were generated with the aid of CFD simulation tools and according to the real geometry of each component. The control logic of the studied gas turbine was simplified and coupled with the developed engine performance model. Also, the gas turbine actuators including variable inlet guide vanes, compressor bleed valves, and fuel valves were simulated so that their concurrent effects on the gas turbine transient behavior can be captured precisely. Moreover, the air-cooled compressor turbine was modeled with a new approach. The integrated model was set up and then tuned with the field data in the base load condition. Next, the start-up operation of the gas turbine from zero speed to the base load condition was simulated and validated with the field data. The results show good agreement between the model outputs and field data. Regarding the model outputs, it can be used as the base code for a more comprehensive investigation of flexibility, operability, and the life concerns of this type of gas turbines.

Under the background of the development of construction waste recycling in China, optimizing the site of construction waste recycling and disposal plant is important, considering not only the cost of construction waste recycling but also the impact on the surrounding environment. This study aims to minimize the cost and negative environmental effects. In order to find the best method to solve the problem of multiobjective function optimization, we propose a multiobjective location model which combines genetic algorithm with probabilistic robust optimization. The model first uses genetic algorithm to get preliminary result and then it uses probabilistic robust optimization to find the optimal solution. The preliminary results show that 1, 3, 5 of the candidate sites more cost-effective and environmentally friendly than other. The fitness value converges at a stable value of 1.55 × 10−5, and the Pareto optimal frontier presents considerable clustering characteristics, which prove the rationality and operability of the site selection optimization model. Meanwhile, the robust model analysis under the given uncertain environment achieves the purpose of further optimization of the site. The research results can provide the government with a theoretical basis for the site selection of construction and demolition waste recycling plants.

Rapid and accurate analysis of food draws considerable attention in the modern pace of the world due to the close relationship between human health and food safety. Traditional detection technologies for food evaluation are often restricted by high cost, lengthy time, bulky instruments and trained personnel. The marriage of biosensors with smartphones enables the development of powerful analysis platforms for food evaluation including detection of food contaminants, toxins, pathogens, allergens and nutrition. Here, we provide an overview of recent developments on smartphone-based biosensors for portable food evaluation. Owing to operability, connectivity, portability and built-in sensors, smartphones have become ideal control, interaction and analysis tools in the on-site sensing systems. Fusion of smartphones with different kinds of sensitive and selective biosensors enables to develop portable and user-friendly analytical devices. In addition to introducing technical principles, detection methods and selected applications in food science, challenges and future perspectives for smartphone-based biosensors are also discussed.

The United States Department of Energy is developing transformational fossil fuel combustion technologies that result in more efficient power cycles and/or substantial reductions in GHG emissions. Chemical Looping Combustion (CLC) has the potential to achieve a lower cost of electricity than a supercritical pulverized coal power plant with an amine absorption system. Although the concept and research on chemical looping has a long history, CLC has numerous technical issues that must be addressed prior to a commercial debut. This effort is directed toward the following major issues for CLC: (1) demonstrating continuous solids handling, operability, and reactor performance at autothermal conditions and (2) preliminary assessments of oxygen carrier attrition and relative material make-up costs. These are critical issues that should be addressed under realistic conditions prior to directing resources toward larger scale demonstrations. This paper will also describe NETL’s small 50-kWth natural gas circulating CLC test facility located in Morgantown, WV. Despite its small size, this experimental test unit has operated at autothermal conditions for 11 h using a copper-iron-alumina oxygen carrier developed at NETL. This paper will describe the test facility and operating experiences using NETL’s “Gen 2.0” oxygen carrier material. Natural gas conversion to CO2 ranged from 70 to 90% over approximately 75 oxidation-reduction cycles during the autothermal operating period. Estimates for the process specific attrition rate during autothermal operation are also presented. Finally, estimates for the oxygen carrier makeup cost, specific to the NETL process configuration, are several orders of magnitude greater than the NETL target. Future work should focus on reducing the oxygen carrier material cost and improving the attrition resistance of the oxygen carrier material under autothermal test conditions.

Olefin plants employ multi-type cracking furnaces in parallel to convert various hydrocarbon feeds into products such as ethylene and propylene. The cracking process of each furnace is a performance-decaying batch operation, which needs periodic shutdowns for decoking and thus involves inherent and frequent upsets to the downstream process. Thus, the furnace feed allocation, batch processing time, and decoking sequence of the entire furnace system must be optimally scheduled to maximize the plant profitability as well as minimize the process upset induced by furnace decoking for the sake of the plant operability. In this paper, a novel MIQCP (mixed-integer quadratically constrained programming) model has been developed for the optimal scheduling of such parallel and performance-decaying unit system with consideration of inherent upset reduction. The idea is to group decoking operations of different furnaces together, so that the downstream has less frequency to suffer the product throughput upsets from the furnace system. The MIQCP model also addresses major scheduling issues of furnace systems, such as semi-continuous operation, non-simultaneous shutdowns, and secondary ethane cracking. The MIQCP model can be further converted to the MILP model by piece-wise approximation to speed the solving time. Case studies have demonstrated the efficacy of the developed methodology with significant economic potential and operational benefits.

The process industry has experienced technological advances, such as automatic handling of hazardous substances, process equipment, and valves. High levels of automation, as well as system interactions at component and system levels, have brought new challenges to risk management. A modern process system involves multiple controllers. Even if each controller can control the process individually, an unexpected event may occur due to unintended interactions or insufficient attention to safety requirements and constraints. Recent accidents in Plymouth, UK, and Nigeria have attracted the attention of scientists, who have concluded that approaches currently being used are insufficient. A traditional hazard analysis tool, such as Hazard and Operability Studies (HAZOP) or simple reliability analysis methods such as Failure Mode and Effect Analysis (FMEA) cannot investigate the lack of complex systems properly. System Theoretical Process Analysis (STPA) is established to evaluate the safety of such complex systems. It has been used successfully in automated missiles and driving vehicles. However, the use of STPA in process industry applications is scarce. This paper is written to evaluate the feasibility of using STPA in process industry applications. A comparative analysis is conducted between STPA and HAZOP to determine whether STPA can replace traditional HAZOP or not with the help of a case study: Liquefied Natural Gas (LNG) Ship-to-Ship (STS) transfer. The results of the analysis show that STPA is complementary to traditional HAZOP. However, this conclusion is drawn based on only one specific case study (LNG STS transfer) and requires further analysis of other process applications for validation.

Process intensification (PI) is an emerging concept in chemical engineering that describes the design innovations that lead to significant shrinkage in size and boost in efficiency of a process plant. Distillation, the most commonly used separation technique in the chemical industry, is a crucial component of PI. Here, we systematically discuss the following aspects of PI in non-azeotropic multicomponent distillation: (1) Introducing thermal couplings to eliminate intermediate reboilers and condensers to save energy and capital cost; (2) Improving operability of thermally coupled columns by means of eliminating vapor streams in thermal couplings with only liquid transfers or column section rearrangement; (3) Enabling double and multi-effect distillation of thermally coupled configurations to further reduce heat duty; (4) Performing simultaneous heat and mass integration among thermally coupled columns to reduce the number of columns and heat duty; and (5) Conducting any thermally coupled distillation in n-product streams using 1 to n − 2 column shells with operable novel dividing wall columns. We demonstrate these aspects of PI through examples to illustrate how they lead to compact, easy-to-operate, energy efficient and cost effective multicomponent distillation system designs.

The development of edge computing has allowed the Internet of Things (IoT) to reach higher levels of operational efficiency, knowledge generation, and decision-making through a better relationship between applications and their users. The principal idea is the processing of large amounts of data close to the network edge, where these data are generated. Hence, in this paper, the use of a machine learning technique, known as averaged one-dependence estimators, is proposed for real-time pregnancy data analysis from IoT devices and gateways. This statistical technique is useful for decentralized pre-processing of data and its intermediate storage, reducing the amount of data to be transferred to the cloud and ensuring operability, even in an event of network failure. The results show that this technique presents accurate results with a low computational cost and could be a useful tool to better take advantage of the potential of IoT solutions in healthcare.

Pyroprocessing treats nuclear fuel using electrochemical techniques for a variety of applications, whether to process used uranium oxide fuel for back-end management, or to reprocess used metallic fuel for an advanced fuel concept. Since there are proliferation risks associated with special nuclear material (SNM) processed in a pyroprocessing facility, the high reliability safeguards (HRS) methodology has been developed to implement safeguards, safety, and physical security (3S) together with operations from a design-driven perspective. This paper suggests the design strategies by integrating a hazard and operability (HAZOP) analysis. It is a process hazard analysis, essential for identifying hazards, operability issues, severe accident scenarios, and for mitigating consequences with the corresponding protection methods. It is a preliminary step for an eventual quantitative, probabilistic risk analysis, which may be needed for obtaining an operating license for a commercial pyroprocessing facility. The focus of this HAZOP analysis was on major pyroprocessing subsystems; voloxidation, electroreduction, electrorefining, electrowinning, and the argon atmosphere control system. Deviations were analyzed from normal operating conditions, and methods were thoroughly prepared to prohibit or mitigate off-normal situations. Importantly, pressure buildup or high temperature in the systems can increase the risk of initiating fire/explosion, which may eventually release radiation to the outside. Safety relief valve installations, valve actuation and heater automatic shutdown systems, etc., would be helpful to alleviate operational problems. This enhanced HAZOP also suggests a strong safeguards design for the facility by proposing nuclear material accounting (NMA) locations for the purpose of reducing potential proliferation risks.

In the framework of emerging Global Warming strategies, CO2 sequestration pipelines require attentive hazard studies to ensure a safe operability, but current risk assessment procedures applied to CO2 pipeline failures lack reliable and comprehensive source models. This work suggests a resolutive and robust multiphase discharge model suited for matching all expected CO2 discharge mechanisms. The application to real scale CO2 pipelines shows an essential incidence of the pipeline geometry (length and internal diameter) as well as of the orifice size on the release features. Wider thermal dynamics and enlarged solid contents are expected in short pipelines subjected to large ruptures. The resulting expansion transformations are characterized by increasing degrees of reversibility. Results show that expected solid content may amount up to 45% on a mass basis under usual carbon sequestration operative conditions. The latter, being linked to the initial CO2 aggregation state, play a key role in determining the whole discharge dynamics especially because of the effects of phase change mechanisms. A peculiar mass flow rate discharge profile is observed depending on the occurrence of liquid-vapor and solid-vapor mixtures. Specific set of geometric and operative conditions allow for the applicability of the isothermal bulk hypothesis and negligible wall effect in heat transfer mechanisms. Main governing parameters are the ratio between the pipeline length and internal diameter L/D and that between the orifice and the internal pipeline diameter d/D. Essential in driving the QRA procedure is the occurrence of the solid phase in rapid depressurizations that is expected only for pipeline shorter than 1500 m subjected to d/D > 0.30. Independently on the operative temperature, only pipelines carried at pressures above 55 barg lead to CO2 solid-vapor mixtures. Under these conditions, the solid CO2 cannot be neglected thus requiring a QRA modelling procedure considering additional scenarios involving sublimative dynamics of a dry ice bank.

The four-product extended Petlyuk dividing-wall column (FPEP-DWC) saves 50% more energy than traditional distillation sequences. However, the complex structure of FPEP-DWC results in strong interactions between different control loops and highly nonlinear behaviors. For the control of the FPEP-DWC, the temperature control (TC) scheme fails to handle the disturbances inserted into the process and none of the existing control schemes can, to the best of our knowledge, avoid the use of a composition controller (which is not recommended in industrial processes). The proposed TC scheme in the current work is also unable to handle the disturbances. Therefore, a kind of temperature difference control (TDC) scheme is investigated for the FPEP-DWC to improve its controllability and operability. A pressure-compensated temperature difference control (PCTDC) is also studied for the FPEP-DWC to compensate the pressure variations. To provide an illustrative example of the FPEP-DWC fractionating, a mixture containing methanol, ethanol, 1-propanol, and n-butanol was used to verify the feasibility of the TDC and PCTDC schemes while a wide range of feed disturbances are confronted. The outcomes show that the dynamic performances of the FPEP-DWC are substantially enhanced in most cases by using the proposed TDC and PCTDC schemes, which are conducive to the industrialization of the FPEP-DWC.

Without careful consideration of aerodynamic installation effects on exhaust system performance the projected benefits of high bypass ratio engines may not be achievable. This work presents a computational study of propulsion system integration in order to quantify the effect that aircraft installation has on the aerodynamic performance of separate-jet aero-engine exhaust systems. Within this study the sensitivity of exhaust nozzle performance metrics to aircraft incidence and under wing position were investigated for two engines of different specific thrust. Upon installation, thrust generation was found to be beneficial or detrimental relative to an isolated engine depending on the position of the engine relative to the wing leading edge. The dominant installation effect was observed on the exhaust afterbodies and, over the range of engine positions investigated at cruise conditions, the installed modified velocity coefficient was shown to vary up to 1% relative to an isolated engine. Furthermore, due to variations in the core nozzle mass flow rate by up to 10% relative to an isolated engine, it is concluded that aerodynamic installation effects need to be taken into consideration when sizing the core nozzle in order to ensure engine operability.

In recent years, worker shortages in the field of urban construction are looming as an important issue. To address this difficulty, direct-vision remote control of a construction machine can be an effective solution by which a worker can play not only the role of an operator but also play the role of a manual laborer.This study examines a new direct-vision remote control system for an excavator using a tablet device. To realize an intuitive interface, we propose the following graphical user interfaces (GUI) of two kinds: input bucket velocity using virtual joysticks, and input bucket position by dragging a bucket. We conducted a usability evaluation experiment simulating a horizontal digging operation. Operability of the GUIs were compared with that of a GUI resembling the conventional International Organization for Standardization (ISO) teleoperation interface. The experimental result concludes that proposed two GUIs superior to the conventional interface in task execution time, accuracy, and subjective usability evaluation.

Weighting is an important step that supports comparison and decision-making in the LCA (Life Cycle Assessment) of buildings. However, temporal variations of weighting systems have not been adequately studied. Given the increasing demand of addressing time issues in LCA, this study attempts to develop a dynamic weighting system. Three common weighting approaches—expert panel, monetization, and DTT (distance-to-target)—are compared, and the DTT approach is selected for utilization. Temporal variations of emission targets and resource characteristics are considered in the new weighting system, which includes short-term, medium-term, and long-term weighting factors. The dynamic weighting system makes it possible to quantify environmental impacts with temporal-varying environmental policies and planning, and the assessment results could better guide design improvements with various environmental priorities in different periods considered. A residential building is taken as case to test the operability of the new weighting system. The significant difference between the assessment results weighted by the traditional versus the dynamic weighting systems indicates the necessity of considering temporal variations.