External Failure Research Articles

Isoproterenol and phenylephrine infusions in a dog with sick sinus syndrome following external pacing failure: morbidity and mortality

Isoproterenol and phenylephrine infusions in a dog with sick sinus syndrome following external pacing failure: morbidity and mortality

Dynamic mechanical characteristics of coal in front of the mining face under different mining layouts

To study the dynamic mechanical characteristics of coal in the area affected by mining in front of the mining face under different mining methods, an improved split Hopkinson pressure bar (SHPB) was used to apply different static loads to different positions. Then, dynamic mechanical tests were conducted on coal at different positions on the mining face, analyzing the dynamic response under strong dynamic load disturbances, under three different mining layouts. Within the range of static water pressure to the peak support pressure, the dynamic strength of coal gradually increases with increasing distance from the mining face. The dynamic strength is the smallest at the peak support pressure stress, and under strong external disturbances, instability and failure are increasingly likely to occur at the peak stress. Under the same loading rate conditions, the dynamic strength of the peak stress in coal is as follows: Protective coal-seam mining (PCM) > Top-coal caving mining (TCM) > Nonpillar mining (NM).

A surface-shunting method for the prevention of a fault-mode-induced quench in high-field no-insulation REBCO magnets

In this paper, we apply a surface-shunting method to prevent quenches in no-insulation (NI) REBCO magnets triggered by external failures of magnet current leads or power suppliers (i.e., fault mode). In a high-field magnet system, an NI coil may still be at risk during the mentioned quench events even if the whole magnet is well-designed, non-defective, and properly operated. The mechanism of this fault-mode quench initiation and propagation still remains unclear, complicating the development of reliable quench protection. Here, we present this mechanism to demonstrate a corresponding practical quench-preventive approach named surface shunting, which utilizes a low-temperature solder attached to the top and bottom of pancake coils. We validate the effectiveness of this approach by comparing the electromagnetic, thermal, and mechanical behaviors in the fault mode with and without the shunt. We conclude that the surface shunt suppresses the fault-mode quench initiation and propagation by redirecting the original turn-to-turn current and induced overcurrent out of the NI winding. We anticipate this work can provide a solution to improve the operational safety of high-field HTS NI magnets against quench and potential damage during fault modes.

Event-triggered adaptive fault-tolerant control with pre-specified performance for AUVs trajectory tracking

This paper investigates the problem of fault-tolerant control of the preset performance of autonomous underwater vehicles (AUVs) in case of external disturbances and actuator failures. To begin with, a specific new nonlinear auxiliary function with dual performance constraints is designed to establish the foundation for achieving prescribed performance in the closed-loop system. Subsequently, an event-triggered fault tolerant controller employing Nussbaum gain technique is introduced to accomplish the precision trajectory tracking control of the AUVs by predetermining control index. It is shown that the effect by resulting in actuator faults is on-line compensated by an adaptive estimator. Theoretical analyses demonstrate the boundedness of the signals of the designed closed-loop control system, and the Zeno phenomenon can be effectively avoided. Finally, simulation experiments are conducted to verify the effectiveness of the proposed methods.

Effect of loading rate on local deformation of rock-like models with locked segment

To investigate the influence of loading rate on the local deformation and failure characteristics of rock-like models with a locked segment, this study fabricated them using quartz sand and barite powder as aggregates, and gypsum as cementing material. Uniaxial compression tests, combined with strain cube monitoring and the digital image correlation technique, were employed to analyze the mechanical properties, internal and external deformation characteristics, crack propagation, and failure modes at different loading rates. The results showed that as the loading rate increased, the strength of these models initially increased significantly and then slightly decreased, primarily due to the complex interaction between the longitudinal and transverse deformations of the models and the stress concentration intensity at the crack tips. The fluctuation in the principal strain axis's deflection angle revealed the complex process of stress wave propagation and particle adjustment within the models, with more pronounced fluctuations observed at higher loading rates. The stress intensity factors, KIand KII, at the crack tips first increased and then decreased with increasing loading rate, with KI consistently higher than KII. The strain concentration phenomenon in the rock-like models occurred earlier with increasing loading rates, and the corresponding crack closure stress exhibited a decreasing trend. Higher loading rates caused earlier crack initiation and faster propagation. As the loading rate increased, the crack paths shortened, and both damage density and severity increased significantly, indicating brittle failure. This study provides important experimental evidence and theoretical support for understanding the effects of loading rate in rock mass engineering.

Machine-learning-based sampling inspection under OQC capacity for real-time quality monitoring in the TFT-LCD industry

ABSTRACT In the thin film transistor-liquid crystal display (TFT-LCD) industry, the competition is fierce, and the external failure cost is high. To improve the quality of released products, sampling inspection under outgoing quality control (OQC) is conducted before products are released. Owing to the variety and complexity of inspection items, the task must be carried out manually while realising automation is difficult. Traditional random sampling inspection is limited by sampling quantity, manpower, and material resources. To effectively improve acceptable quality levels, this paper proposes a quality predictive monitoring framework tailored to the production and inspection characteristics of the TFT-LCD industry. This framework includes real-time automatic quality monitoring based on an optimal machine learning prediction model with two-phase feature creation, and it also addresses OQC inspection capacity constraints. Experimental results show the prediction performance based on proposed model is better than the traditional random sampling process. In practice, superior average outgoing quality improves by more than 70% at the same sampling level. In addition, the features of the process can be further controlled and managed based on the prediction model to monitor the key parameters in real time and respond to abnormalities quickly, thereby further improving the quality of released products.

THE RELATIONSHIP BETWEEN THE IMPLEMENTATION OF QUALITY COSTS AND EFFORTS TO IMPROVE PRODUCT QUALITY (A CASE STUDY AT PT INDUSTRI JAMU DAN FARMASI SIDO MUNCUL TBK)

The use of herbal medicine products has seen a decline in trust due to a lack of scientific evidence proving their effectiveness, perceptions of unsafe or unhygienic ingredients, and the negative stigma that views herbal medicine as an outdated form of treatment. However, herbal medicine is believed to have fewer side effects due to the use of natural ingredients passed down through generations. Despite this, many herbal products with chemical ingredients and easily accessible imported herbal products negatively impact the development of traditional herbal medicines, especially in small-scale industries that lack standardization in line with Good Traditional Medicine Manufacturing Practices. Quality costs are the expenses incurred to perform all activities related to the development of product quality. These costs include prevention, appraisal, internal failure, and external failure costs. Quality costs serve as an indicator of product quality success and competitive advantage. PT Industri Jamu dan Farmasi Sido Muncul, the largest herbal medicine producer in Indonesia, strives to improve product quality through consistent supervision and quality enhancement. This study employs a case study method to analyze the relationship between the implementation of quality costs and efforts to improve product quality at PT Sido Muncul. The findings indicate that effective quality cost control contributes to product quality improvement, reduces defective products, lowers costs, and increases profits. Sido Muncul emphasizes the use of science, technology, and research to create high-quality products. Thus, significant investments in product quality improvement provide the company with a competitive advantage, enabling it to maintain and increase its market share. Keywords: Cost Concept, Product Quality, Quality Costs

Cost of Quality Management: Encouraging Business Leaders to Manage and Invest in Quality Enhancement

The quality management is a complex set of constant activities aimed at improving the quality of products and services, regularly evaluating and monitoring it, preventing defects, limiting and reducing malfunctions, and correcting production defects before and after the sale of goods. Ineffective quality management leads to such problems as product returns, claims, replacement or repair, loss of customer base, damage to brand reputation, etc. This paper aims to analyze advanced strategies, methodologies, methods and tools for effective control of quality management costs, ways and means of their strategic integration into the practice of business quality management, emphasize the importance of optimizing the cost of quality management in enterprises. The proposals developed in this article are demonstrated on the example of the woodwork division of MEKKERA (MDM), a subsidiary of the HASNAOUI Group in Algeria. An approach represented in the article combines qualitative and quantitative methods. Qualitative data collection involved semi-structured interviews with four company managers, processed using NVIVO software. The purpose of these interviews was to understand the reasons that led the company to include the evaluation of the Cost of Quality in its quality objectives for 2023, as well as the perspectives and goals aimed for by the company in this initiative. A Quantitative analysis relied on secondary data from the company’s database: direct quality costs were calculated using the P-A-F and Ferrebœuf models, prevention and detection measures’ effectiveness and production process performance were evaluated; key performance indicators for indirect quality acquisition costs were defined. Findings revealed the company exceeded set thresholds for internal and external failure costs, necessitating improvements. Ishikawa method identified causes, and corrective actions were proposed using Failure Mode and Effects Analysis (FMEA).

PENGARUH PENYEBAB KEGAGALAN BERWIRAUSAHA TERHADAP PEMBELAJARAN DARI KEGAGALAN BERWIRAUSAHA DAN DAMPAKNYA TERHADAP KINERJA UMKM

The main objective of this research is to examine the influence of the causes of entrepreneurial failure by using two types of causes of entrepreneurial failure (internal causes and external causes) on learning from entrepreneurial failure and its impact on the performance of SMEs in DKI Jakarta. The research method used in this research is a quantitative research method using a survey with the analytical tool used, namely Smart PLS version 3.0. which aims to examine the variables that cause internal failure, the causes of external failure, learning from entrepreneurial failure and its impact on business performance variables. The research results show that the variable learning from failure has a significant positive effect on business performance. Likewise, the variables that cause entrepreneurial failure from internal factors have a positive and significant effect on learning from entrepreneurial failure. However, in contrast to the results of testing variables that cause failure from external factors on learning from entrepreneurial failure, it shows that there is no influence on the causes of entrepreneurial failure from external factors on learning from entrepreneurial failure. It is hoped that this research can provide suggestions and input, especially for SMEs, so that they can turn entrepreneurial failures into lessons to improve business performance. This research also has several limitations, including that the SME business sector in this research is still too general, and this research only uses subjective performance measures.

Experimental study on the effect of flexible joints of a deep-buried tunnel across an active fault under high in-situ stress conditions

During dislocation, a tunnel crossing the active fault will be damaged to varying degrees due to its permanent stratum displacement. Most previous studies did not consider the influence of the tunnel’s deep burial and the high in-situ stress, so the results were not entirely practical. In this paper, the necessity of solving the anti-dislocation problem of deep-buried tunnels is systemically discussed. Through the model test of tunnels across active faults, the differences in failures between deep-buried tunnels and shallow-buried tunnels were compared, and the dislocation test of deep-buried segmental tunnels was carried out to analyze the external stress change, lining strain, and failure mode of tunnels. The results are as follows: (1) The overall deformation of deep-buried and shallow-buried tunnels is both S-shaped. The failure mode of deep-buried tunnels is primarily characterized by shear and tensile failure, resulting in significant compressive deformation and a larger damaged area. In contrast, shallow-buried tunnels mainly experience shear failure, with the tunnel being sheared apart at the fault crossing, leading to more severe damage. (2) After the segmental structure design of the deep-buried tunnel, the “S” deformation pattern is transformed into a “ladder” pattern, and the strain of the tunnel and the peak stress of the external rock mass are reduced; therefore, damages are significantly mitigated. (3) Through the analysis of the distribution of cracks in the tunnel lining, it is found that the tunnel without a segmental structure design has suffered from penetrating failure and that cracks affect the entire lining. The cracks in a flexible segmental tunnel affect about 66.6% of the entire length of the tunnel, and cracks in a tunnel with a short segmental tunnel only affect about 33.3% of the entire length of the tunnel. Therefore, a deep-buried tunnel with a short segmental tunnel can yield a better anti-dislocation effect. (4) By comparing the shallow-buried segmental tunnel in previous studies, it is concluded that the shallow-buried segmental tunnel will also suffer from deformation outside the fault zone, while the damages to the deep-buried segmental tunnel are concentrated in the fault zone, so the anti-dislocation protection measures of the deep-buried tunnel shall be provided mainly in the fault zone. The results of the above study can provide theoretical reference and technical support for the design and reinforcement measures of the tunnel crossing active fault under high in-situ stress conditions.

Adaptive sliding mode and RBF neural network based fault tolerant attitude control for spacecraft with unknown uncertainties and disturbances

Taking the external disturbance, model uncertainty, actuator failure, and actuator saturation into consideration, this paper investigates the nonlinear fault-tolerant attitude control problem for the spacecraft. First, to deal with the disturbance and uncertainty with unknown boundaries, an adaptive sliding mode control method is proposed to stabilize the state variables of the spacecraft attitude control system. Then the actuator failure and saturation are further considered, and the second spacecraft fault-tolerant attitude controller is derived based on adaptive sliding mode control and radial basis function (RBF) neural networks. The adaptive control gains reduction technique is applied in the design process, which can weaken the chattering phenomenon of the controller to some extent, and the stability of the attitude control system is analyzed through Lyapunov theory. In the proposed controller, model information and external disturbance are not required and only the system states are needed. Furthermore, the boundaries of the model uncertainty, external disturbance, actuator fault and saturation are assumed to be existing but unknown by the proposed controllers. These features make the proposed attitude controllers need few modeling information of the spacecraft, or maintain strong robustness even if the model or external environment occurs significant changes. Finally, numerical simulations demonstrate the great performance of the proposed fault-tolerant attitude control method.

Multi-objective integrated attitude control of large solar power satellite: A distributed incremental predictive approach

This paper addresses the multi-objective integrated attitude control problem of a large solar power satellite (SPS) in the presence of time-varying parameters, disturbances, and actuator saturation. The attitude coupling dynamic model, which could accurately describe the rotational motion of different SPS components, is firstly obtained. The gravity gradient, solar radiation pressure, microwave radiation reflection, and friction torques are investigated to evaluate their influence on attitude control accuracy. The coupling dynamic model is linearized and discretized, which provides a subsystem model for distributed controller design. A distributed incremental predictive controller is designed for each rotation channel to form a distributed system. The augmented system state is defined to solve the complex constraint problem, and the predicted value with feedback correction is introduced to deal with the disturbances. Besides, the stability of the system is analyzed by considering external disturbances and actuator failure. Comparative analysis with centralized methods under the same prediction horizon is provided, and the results demonstrate a tenfold solution performance enhancement while maintaining accuracy. Furthermore, the controller is integrated with feedback correction, which could improve control accuracy by at least one order of magnitude. The proposed controller reduces the adjusting time for attitude stabilization by 56.8 % in the presence of actuator failure. The simulation results demonstrate that the proposed controller has good robustness and fault tolerance, which provides a feasible solution for SPS multiple attitude control missions.

Analysis of Drone Wireless Communication System Performance Affected by Vibration based on 1DCNN

Developments in drone technology have made them crucial in various fields. Vibrations caused by external conditions or mechanical failures in a drone's design can significantly affect the efficiency of the drone's communication systems. The drone's antenna generates phase noise, which can degrade the performance of drone communications systems. This work presents an analysis and computational model of how drone vibration affects system performance. by using two steps. The first one uses the simulation Monte-Carlo in MATLAB when the iteration algorithm processes with various variable values as the frequency carriers and the order of the quadrature-amplitude-modulation (M-QAM) system and evaluates the performance of the communication system by measuring the symbol error rate. The second step uses the one-dimensional convolutional neural network to predict the symbol error rate. After creating the dataset in the first stage, reprocess it and split it into 70% training and 30% testing. Then, by MATLAB App Designer created a graphical user interface (GUI) for friendly use. The result appears to be that the performance of the drone communication system decreased when frequency carriers and modulation order for M-QAM increased due to the impact of a vibrating antenna. Our contribution to this work is using 1DCNN, unlike other works that only use simulation to evaluate the performance, because 1DCNN can automatically extract useful features from the input dataset to evaluate the effect. This study provides a valuable method to evaluate the efficiency of a communication system on the UAV, which is particularly important for drone wireless system planning. In our next work, we propose investigating other factors affecting UAV communication systems, including humidity and temperature.

Formation fault-tolerant control for multiple UAVs with external disturbances

PurposeThe purpose of this paper is to construct an event-triggered finite-time fault-tolerant formation tracking controller, which can achieve a time-varying formation control for multiple unmanned aerial vehicles (UAVs) during actuator failures and external perturbations.Design/methodology/approachFirst, this study developed the formation tracking protocol for each follower using UAV formation members, defining the tracking inaccuracy of the UAV followers’ location. Subsequently, this study designed the multilayer event-triggered controller based on the backstepping method framework within finite time. Then, considering the actuator failures, and added self-adaptive thought for fault-tolerant control within finite time, the event-triggered closed-loop system is subsequently shown to be a finite-time stable system. Furthermore, the Zeno behavior is analyzed to prevent infinite triggering instances within a finite time. Finally, simulations are conducted with external disturbances and actuator failure conditions to demonstrate formation tracking controller performance.FindingsIt achieves improved performance in the presence of external disturbances and system failures. Combining limited-time adaptive control and event triggering improves system stability, increase robustness to disturbances and calculation efficiency. In addition, the designed formation tracking controller can effectively control the time-varying formation of the leader and followers to complete the task, and by adding a fixed-time observer, it can effectively compensate for external disturbances and improve formation control accuracy.Originality/valueA formation-following controller is designed, which can handle both external disturbances and internal actuator failures during formation flight, and the proposed method can be applied to a variety of formation control scenarios and does not rely on a specific type of UAV or communication network.

Analysis of power plant outage event results based on SOM clustering

Through the file mining analysis of fault event analysis reports, it is possible to discover the fault mode characteristics that exist between different fault events, thereby providing empirical guidance for safety management. The self-organizing mapping SOM clustering method was used to analyze the fault cause characteristics of 520 unplanned shutdown events in power plants. The main influencing factors are divided into six primary indicators: external factors, technical factors, equipment failures, pipeline failures, logical factors, and human factors, and 36 secondary indicators of influencing factors. Based on different indicator characteristics, the power plant shutdown event can be mapped into a two-dimensional fault feature event map, which can intuitively obtain the visualization results of shutdown events with different influencing factor dimensions. Through SOM clustering analysis, the shutdown fault events were ultimately divided into three different clusters. In cluster 1, the highest proportion is ultimately caused by external influencing factors and equipment failures. In cluster 2, it is mainly affected by human factors and control logic factors. In cluster 3, it is mainly the pipeline aging failure caused by long-term running time factors. By visualizing the results of intuitive fault characteristics, it can provide diversified knowledge information for risk management and technical personnel to take corresponding measures to improve the safe and stable operation of the unit.

Global Financial Crisis: Unravelling Corporate Governance Failures

The global financial crisis of 2007-2008, stemming from the United States subprime mortgage crisis, was a profound and widespread calamity with far-reaching implications for economies, enterprises, and investors worldwide. This essay posits that the root cause of this crisis lies in the failure of corporate governance, asserting that the outbreak unfolded through three stages: the accumulation, amplification, and outbreak of governance risks. Crucially, the first stage reveals a convergence of internal and external governance failures, marking the conjunction of internal governance lapses—specifically in risk management, executive compensation, board operations, and information disclosure—and external governance deficiencies in government regulation, legal requirements, and social accountability. The multifaceted impact of the crisis, leading to the bankruptcy of prominent financial institutions globally and unprecedented government interventions, underscored the urgency of addressing governance issues. Scholars and researchers globally have since dissected the crisis, identifying lessons and recommending reforms. This essay examines the intricate balance between internal and external governance, emphasizing the imperative of effective interaction. Proposals for improvement include enhancing board structures, implementing substantive disclosure rules, fortifying government regulation, and fostering international cooperation. The aftermath of the crisis, while posing challenges, also presents an opportunity for corporate governance reform. The lessons learned highlight the indispensability of robust governance mechanisms in protecting investor and shareholder interests. Effectively navigating the evolving landscape requires staying abreast of contemporary needs and embracing reforms that align with the dynamic nature of global finance. Ultimately, the financial crisis underscores the pivotal role of effective corporate governance in mitigating risks, fostering sustainable development, and safeguarding societal interests.

The Endoscopic Endonasal Dacryocystorhinostomy in Daraa Tafilat –Sud Est Area of Morocco

Objective: The endoscopic endonasal dacryocystorhinostomy (EE-DCR) surgery is a minimally invasive surgery for lacrimal sac. The aim of our study is to analyze and evaluate our patients undergoing EE-DCR during 12 months. Patients et methods: First retrospective study of 23 EE-DCR in Daraa-Tafilalt, sud est area of Morocco from 01/01/2021 to 30/12/2022. This work is an ananalysis of epidemiological data, operative indications, clinical and radiological findings of intraoperative and postoperative anatomical and functional results. Results: This study included 20 women (86.9%) and 3 men. The median age is 45 years. Surgical indications are divided between failure of DCR externally (7 cases), nose and sinus associated pathology (11 cases), dacryocele (5 cases). Our success rate is 87,5% in first-line DCR (14/16). It is 85,7% in revision of external failure. No major complication is collected. Conclusion: The EE-DCR is becoming increasingly widely adopted and is now the preferred DCR technique in many centres. It remains just as effective and reliable than externally with a success rate almost comparable (85% to 90%). The success of an EE-DCR is conditioned by close multidisciplinary collaboration (ENT/Ophthalmologists/Radiologists), a mastery of technical and finally, and a good post-operative care.

Penetration mechanics of ceramic/metal functionally graded plates under ballistic impact: An experimental perspective

This paper deals with a comprehensive experimental analysis of the penetration mechanics and failure mechanisms of SiC/AA6061 functionally graded plates under ballistic impact. The external, cross-sectional, and high-speed photographic damage and failure assessments of the plates were performed. The novelty of this study is to investigate the ballistic impact behavior of a ceramic/metal functionally graded plate with different compositional gradients in a wide range of impact velocities considering below and above the ballistic limit and to reveal a detailed analysis of the damage and failure mechanisms of the plate. This can provide fundamental insights into the design of ceramic/metal functionally graded armor materials. The results indicate that the metal-dense gradient plate shows localized ductile failures as ductile perforation and plugging, whereas the ceramic-dense gradient plate exhibits brittle failures as comminution and conoidal fracture. Tailoring a relatively continuous compositional gradient instead of an abrupt variation, namely the linear gradient, provides tensile stress wave attenuation and resistance to crack growth and fracture.

Deep MARL-Based Resilient Motion Planning for Decentralized Space Manipulator

Space manipulators play an important role in the on-orbit services and planetary surface operation. In the extreme environment of space, space manipulators are susceptible to a variety of unknown disturbances. How to have a resilient guarantee in failure or disturbance is the core capability of its future development. Compared with traditional motion planning, learning-based motion planning has gradually become a hot spot in current research. However, no matter what kind of research ideas, the single robotic manipulator is studied as an independent agent, making it unable to provide sufficient flexibility under conditions such as external force disturbance, observation noise, and mechanical failure. Therefore, this paper puts forward the idea of “discretization of the traditional single manipulator”. Different discretization forms are given through the analysis of the multi-degree-of-freedom single-manipulator joint relationship, and a single-manipulator representation composed of multiple new subagents is obtained. Simultaneously, to verify the ability of the new multiagent representation to deal with interference, we adopted a centralized multiagent reinforcement learning framework. The influence of the number of agents and communication distances on learning-based planning results is analyzed in detail. In addition, by imposing joint locking failures on the manipulator and introducing observation and action interference, it is verified that the “multiagent robotic manipulator” obtained after discretization has stronger antidisturbance resilient capability than the traditional single manipulator.

Green Accounting Analysis in Public and Private Hospitals

This study aims to determine the applicationof environmental prevention costs, environmental detection costs, internal environmental failure costs and external environmental failure costs in public and private hospitals in Batusangkar. The type of research used is a field research using quantitative methods to see how enviromental accounting is applied in public and private hospitals in Batusangkar. The results of this study indicate that the Hanafiah Hospitals has implemented IPAL properly in accordance with the Minister of Environment Regulation No. 11 of 2020 PP of 2021 but not all categories of Enviromental costs according to Hansen Mowen issued by the RSUD. While at the Harapan Ibunda Hospitals also has its own IPAL facility to manage its waste according the Minister of criteria only the city goverment in the relevant sector conducts an evaluation.