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In industries the reliability engineering place a major role in process availability, safety, probability of failure component etc. Here the plant at Indian Rare Earth Limited is chosen for reliability evaluation. The technique used for the reliability evaluation is fault tree analysis. Open FTA software is used for fault tree analysis. In this paper reliability and failure rate predictions are also carried out using artificial neural network. Here working environment used for ANN is neural lab. [ABSTRACT FROM AUTHOR]

In industries the reliability engineering plays a vital role in process availability, safety and probability of failure components. So this paper is based on the reliability analysis of a process industry. Reliability is the probability that a device continues to perform a particular function over a particular period of time and under stated conditions. Here the plant at Indian Rare Earths Limited is chosen for reliability evaluation. The technique used for the reliability evaluation is fault tree analysis. The approach is based on Fault Tree Analysis (FTA), which is a technique used to obtain the probability of occurrence of an undesired event. Open FTA is the software, used for the Fault tree analysis. This paper also describes the Reliability and Failure rate predictions using Artificial Neural Networks. The working environment used for ANN is Neural LAB. [ABSTRACT FROM AUTHOR]

Multi-state systems (MSS) are systems whose stochastic degradation process is characterised by several performance levels varying from nominal functioning to complete failure. MSS arise naturally in many application areas. MSS reliability evaluation and estimation has received much attention from researchers and a wide range of papers dealing with MSS have been published. In this paper, an approach based on Kronecker algebra combined with stochastic processes is proposed to evaluate the reliability of a series–parallel MSS. The main advantage of the proposed approach is that the mathematical expressions of the MSS reliability indices are derived from data of individual elementary components without generating the whole, possibly huge, MSS state space. Furthermore, the approach is well formalised and easy to implement thanks to Kronecker algebra operators. Examples are given to illustrate the proposed approach. [ABSTRACT FROM PUBLISHER]

Objective: Examine thermocouple model uncertainty (reliability + validity). Design: First, a 3 × 3 repeated measures design with independent variables electro-thermometers and thermocouple model. Second, a 1 × 3 repeated measures design with independent variable subprobe. Intervention: Three electro-thermometers, 3 thermocouple models, a multi-sensor probe and a mercury thermometer measured a stable water bath. Main Outcome Measures: Temperature and absolute temperature differences between thermocouples and a mercury thermometer. Results: Thermocouple uncertainty was greater than manufactures' claims. For all thermocouple models, validity and reliability were better in the Iso-Themex than the Datalogger, but there were no practical differences between models within an electro-thermometers. Validity of multi-sensor probes and thermocouples within a probe were not different but were greater than manufacturers' claims. Reliability of multiprobes and thermocouples within a probe were within manufacturers claims. Conclusion: Thermocouple models vary in reliability and validity. Scientists should test and report the uncertainty of their equipment rather than depending on manufactures' claims. [ABSTRACT FROM AUTHOR]

Reliability assessment gives useful information on the level of performance or adequacy of design rules. There are five standardized Super-T prestressed concrete (PSC) girder sections widely used for bridges in Australia. The Australian standard (AS 5100) requires serviceability limit state criteria of allowable stresses to be met. However, there is not yet an assessment of the performance achieved by these rules. In this study, all potential strand arrangements (more than 50,000) for all Super-T sections, across all feasible span ranges, are assessed. Ten girder-slab bridge decks are analysed; the critical girder in the deck is designed for all possible strand arrangements. Design adequacy is assessed using the annual reliability index. A system reliability analysis is conducted using Ditlevsen bounds to check that none of the four stress limits are exceeded. Generally, it is found that the Super-T girder designs are adequate for most strand arrangements compliant with AS 5100. Further, the reliability varies significantly depending on the selected span, section and strand arrangement. This work informs designers on the reliability performance of Super-T girders designed to AS 5100 and provides background for future revisions of AS 5100. [ABSTRACT FROM AUTHOR]

Abstract Reliability evaluation and fault diagnosis of interconnection networks are important to the design and maintenance of multiprocessor systems. The h -extra connectivity and h -extra conditional diagnosability are important measures for the reliability and fault diagnosis capability of interconnection networks respectively. Due to their many attractive properties, Bubble-sort star graphs have received much research interest recently. In this paper, the minimum h -cluster degree, h -extra connectivity of n -dimensional Bubble-sort star graph (B S n) and h -extra conditional diagnosability of B S n under the PMC model are explored. The following are the main results of this paper: (1) The minimum 2, 3-cluster degree of B S n is determined; (2) The 1, 2-extra connectivity of B S n equals their minimum 2, 3-cluster degree for n ≥ 4 and n ≥ 6 respectively; (3) The 1, 2-extra conditional diagnosability of B S n under the PMC model equals their 1, 2-extra connectivity plus h for n ≥ 4 and n ≥ 6 respectively; (4) An algorithm for determining the h -extra connectivity of general simple graphs is also constructed in this paper and it is used to determine the h -extra connectivity of Bubble-sort star graphs of low dimensions. [ABSTRACT FROM AUTHOR]

The present work investigates the suitability of a new method for the calculation of the performance indicators of domestic solar water heating systems, within the framework of the European Directive implementation for energy labeling of water heating devices. The various methodology approaches suggested by the directives for the calculation of the expected energy yield from the solar thermal products are being analyzed. The presence of significant issues of reliability and objectivity is being brought out, particularly with regard to the SOLCAL method, which is used for the estimation of the expected energy yield of a thermal energy system, by means of the characteristics of each individual component which the system consists of. A detailed documentation and experimental validation of a new method for the estimation of the expected energy yield of a solar only water heater is outlined. The performance of the proposed method is assessed based on an extensive experimental investigation, whereby discrepancies of the order of 7% or less were obtained for the daily energy yield. From the comparison of performance of the new method against that of the SOLCAL method it is inferred that the former constitutes a reliable alternative choice in the context of energy labeling. [ABSTRACT FROM AUTHOR]

Degradation modeling is an effective approach for reliability assessment, remaining useful life prediction, maintenance planning, and prognostics health management. Degradation models are usually developed based on degradation data and/or prior understandings of physics behind degradation processes of products or systems. Further, the effects of environmental or operational conditions on degradation processes and the knowledge about the dependency between degradation processes help improve the explanatory capabilities of degradation models. This paper presents a comprehensive review of existing degradation modeling approaches commonly used in engineering applications. To assist practitioners in understanding the concept of degradation modelling, the existing methods are classified into two broad categories: the data-driven approach and physics-based modelling approach. By systematically reviewing these approaches, we highlight their merits, useful applications and limitations. Finally, we provide a summary and indicate several future research challenges in this important area of reliability engineering. [ABSTRACT FROM AUTHOR]

As a vehicle moves on roads, a complex vibration system of the running vehicle is formed under the collective excitations of random crosswinds and road surface roughness, together with the artificial handing by the drivers. Several numerical models in deterministic way to assess the safety of running road vehicles under crosswinds were proposed. Actually, the natural wind is a random process in time domain due to turbulence, and the surface roughness of a road is also a random process but in spatial domain. The nature of a running vehicle therefore is an extension of dynamic reliability excited by random processes. This study tries to explore the dynamic reliability of a road vehicle subjected to turbulent crosswinds. Based on a nonlinear vibration system, the dynamic responses of a road vehicle are simulated to obtain the dynamic reliability. Monte Carlo Simulation with Latin Hypercube Sampling is then applied on the possible random variables including the vehicle weight, road friction coefficient, and driver parameter to look at their effects. Finally, a distribution model of the dynamic reliability and a corresponding index for the wind-induced vehicle accident considering these random processes and variables is proposed and employed to evaluate the safety of the running vehicle. [ABSTRACT FROM AUTHOR]

This paper presents a new methodology to define a priority scale for maintenance actions in substations, based on the development of a Composite Risk Index (CRI) associated with each device. Two auxiliary indices are built: Basic Condition (BC) and Operating Condition (OC), representing the physical and functional characteristics of the equipment that can compromise their performance and contribute to the occurrence of failures. Their evaluation is helped by a Technical Capacity Index (TCI), which evaluates how much the equipment has been affected by wear and tear, in the assessment of the Basic Condition, and the classification of the equipment defects by degrees of severity, in the assessment of the Operating Condition. Two cascading Fuzzy Inference Systems of the Mandani type are used, the first in defining the BC, and the second to obtain the equipment CRI denoting maintenance priority, which may then be used in planning maintenance actions. The methodology is verified through an SF6 circuit breaker CRI assessment, and its priority scale for maintenance planning. The method for evaluating the SF6 circuit breakers reliability is validated through a comparison with a statistical approach, using real data collected from equipment installed in Eletrobras Eletronorte Transmission System, in Rondônia, Amazon region of Brazil. [ABSTRACT FROM AUTHOR]

Chemoresistive micromachined gas sensors with bottom-electrode configuration and based on Pt-functionalized tungsten oxide nanowires are fabricated. The performance and reliability of three types of devices with different electrode gap (5, 10 and 15 μm) are analyzed in dry and humid ambient and towards various analytes (H 2 , NO 2 , EtOH, and CO). Results demonstrate an improved response, sensitivity, and stability with better dynamic of the response for the sensors with the electrode gap of 5 μm, showing up to 7-fold higher responses and 32-fold faster responses towards hydrogen compared to the sensors with the electrode gap of 10 or 15 μm. These results are connected with the increment of the density of nanowire junctions across the electrodes with 5 μm gap; separation that corresponds to half of the length of the wires used in this work. [ABSTRACT FROM AUTHOR]

This paper is a theoretical and experimental assessment of the solder joint reliability of an advanced high-density interposer-based 2.5-D IC integration technology on-board under drop impact in accordance with the JEDEC standard. Focus is placed on the influences of underfill on the solder joint reliability. The transient dynamic responses of the packaging technology are simulated using Input-G finite element analysis, with the use of the Johnson-Cook model for describing the constitutive behaviors of the solder interconnect materials. Furthermore, an energy-based model is utilized for predicting the drop impact solder joint fatigue life. The effectiveness of the proposed theoretical models is demonstrated through comparison with the drop test experiment. Finally, the effects of some essential factors including the allowed JEDEC shock pulse tolerances are examined in order to establish a design guideline for enhanced shock resistance capability. Results show that underfill and even partial underfill can significantly improve the drop impact solder joint reliability of the 2.5-D IC integration technology. The solder joint reliability turns out to be considerably affected by the shock pulse tolerances, suggesting that there is a crucial need to regularly calibrate the precision of drop testers for minimizing the prediction uncertainty. [ABSTRACT FROM PUBLISHER]

Incorrect responses from protective devices weaken the reliability of microgrids. This paper investigates the effects of the protection system on the reliability performance of a microgrid integrated with weather-dependent microsources. It relies on a stochastic model to simulate the challenges existing in current protection schemes designed for microgrids. Abnormal operating conditions, including overcurrent, overvoltage, and undervoltage, which are detected by a deficient protection scheme, are analyzed by a defined fuzzy virtual setting value. Their contributions, along with the conventional random failure rate achieved by statistical results, are jointly used to evaluate the short-term outage rate of a feeder. A series of fuzzy reliability indices is further proposed for the short-term and periodical reliability of both microgrid system and customers. Subsequently, an evaluation strategy, combined with fuzzy simulation and load restoration, is presented as a solution tool. Simulations on a test system are provided to support the necessity of considering the effects of protection operation in evaluating microgrid reliability. [ABSTRACT FROM PUBLISHER]

Ship collision analysis outcomes are generally used in computational models to derive damage distributions. However, damage is usually assessed after the collision energy has been fully absorbed by structural members rather than at the onset of outer hull fracture. Furthermore, the deformation behaviour of ship structural members under load depends on uncertainty modelling through material, geometric, and structural considerations, captured in an appropriate reliability framework. To consider these significant missed opportunities in understanding the probability of ship structures meeting their performance targets during collisions, a novel stochastic framework is proposed in this paper. For efficient reliability computations, a plate resistance model is developed for hull damage assessment at the onset of failure. Stochastic modelling capabilities of Python scripting are interfaced with Abaqus®to compute the stochastic response. The reliability computations show that the probability of hull fracture increases as the hull deformation progresses, with maximum values occurring at the onset of outer hull fracture. The framework outcomes are useful in determining optimal ship structural design capabilities. [ABSTRACT FROM AUTHOR]

Reliability evaluation is the basis for reliability design of NC machine tools. Since traditional reliability evaluation methods do not consider the working conditions’ effects on reliability, there is a great error of a result of a traditional method compared with an actual value. A new reliability evaluation model of NC machine tools is proposed based on the Cox proportional hazards model, which describes the mathematical relation between the working condition covariates and the reliability level of NC machine tools. Firstly, the coefficients of working condition covariates in the new reliability evaluation model are estimated by the partial likelihood estimation method; secondly, the working condition covariates which have no effects on the reliability of NC machine tools are eliminated by the likelihood ratio test; then parameters of the baseline failure rate function are estimated by the maximum likelihood estimation method. Thus, the reliability evaluation model of NC machine tool is obtained under different working conditions and the reliability level of NC machine tools is obtained. Case study shows that the proposed method could establish the relation between the working condition covariates and the reliability level of NC machine tools, and it would provide a new way for the reliability evaluation of NC machine tools. [ABSTRACT FROM AUTHOR]

Reliability evaluation of Integrated Energy Systems (IESs) based on Smart Agent Communication (SAC) is studied in this paper. The typical structure and reliability evaluation modeling for IESs is firstly introduced. A new reliability evaluation approach is then presented, in which SAC based system reconfiguration is innovatively integrated into the reliability evaluation process. Based on this combination, state evaluation (key procedure of the reliability evaluation) along with system reconfiguration can be conducted autonomously in reliability evaluation. Algorithm and procedures of the system reconfiguration based on a decentralized agent communication algorithm ( K −1 algorithm) is described. The system reconfiguration does not depend on global information of whole system, which can effectively improve reliability evaluation and modeling efficiency. The presented models and approaches are conducted on the multi-paradigm modeling and simulation platform-AnyLogic, and validated by extensive cases studies. [ABSTRACT FROM AUTHOR]

Integrated procedures of analysis have been presented combining both reliability and economical aspects of operation of a water supply system (WSS). The method presented is a practical application of the reliability analysis and life-cycle costing which is a part of a decision support system (DSS) for WSS. It focuses on undisturbed operation of systems with exceeded redundant capacity minding system's reliable and lower possible operational costs. The proposed analytical approach is shown on the example of the surface water intake which is the first subsystem of WSS influencing operation of a whole system. As a part of the study, reliability and economic assessments of various variants of future operation of water intake have been carried out as a basis for choosing most advantageous solution. The authors indicate how exceeded redundant capacity affects applied maintenance method of the system. All calculations of the reliability indicators are based on operating data contained in exploitation logs (2001-2012). The costs have been estimated based on the obtained financial documentation. [ABSTRACT FROM AUTHOR]

The reliability prediction of hybrid electric vehicles (HEVs) is of paramount importance for planning, design, control, and operation management of vehicles, since it can provide an objective criterion for comparative evaluation of various configurations and topologies and can be used as an effective tool to improve the design and control of the overall system. This paper presents a mission-profile-dependent simulation model based on MATLAB for quantitatively assessing the reliability of the electric drivetrain of HEVs. This model takes into consideration the variable driving scenarios, dormant mode, electrical stresses, and thermal stresses. Therefore, more reliable and accurate prediction of system reliability has been achieved. The methodology is explained in detail, and the results of reliability assessment based on a series HEV are presented. Based on reliability analysis, two control strategies are proposed to increase the mean time to failure of HEV powertrains: 1) variable dc-link voltage control and 2) hybrid discontinuous pulsewidth modulation scheme. These novel control schemes reduce the power losses and thermal stresses of power converters, and consequently, enhance system reliability. Numerical simulation results verify the benefits of two proposed control strategies in terms of power losses and reliability. [ABSTRACT FROM PUBLISHER]

A reliable pavement performance prediction model is needed for road infrastructure asset management systems or pavement management systems. In this study, the data on roughness progression of asphalt pavements in the long-term pavement performance (LTPP) database was analyzed in order to develop such a model. The international roughness index (IRI) is a reasonable measure of the ride comfort perceived by occupants of passenger cars and hence used as the basis for the pavement performance prediction model developed in this research. A quantitative relationship between roughness progression and accumulative traffic load, structural number, annual precipitation, and freezing index was developed and validated. Five pavement performance levels were developed to express the extent of asphalt pavement deterioration. This is coupled with a reliability analysis based on the Weibull model to estimate the remaining service life of asphalt pavements. Effective treatments of pavements at the project level for each condition state level were also proposed, which can aid network level optimization of the overall condition and corresponding budget allocations. [ABSTRACT FROM AUTHOR]

Highlights: [•] A probabilistic model on long-term degradation of tendon force is developed. [•] By using the model, we performed reliability evaluation of nuclear containment. [•] The analysis is also performed for the case with the strict maintenance programme. [•] We showed how to satisfy the target safety in the containments facing life extension. [Copyright &y& Elsevier]

Highlights: [•] The most commonly used busbar topologies such as one-and-half breaker and two-breaker are studied in this paper. [•] A complete technical and economical comparison of these topologies is presented. [•] A numerical method based on the Sequential Monte-Carlo Simulation (SMCS) is used to evaluate the reliability of system. [•] The reliability indexes such as EENS, LOLE and ELC are calculated. [•] A real substation layout in Iran national grid is considered as case study. [ABSTRACT FROM AUTHOR]

Abstract: The probabilistic reliability evaluation of composite power systems is a complicated, computation intensive, and combinatorial task. As such evaluation may suffer from issues regarding high dimensionality that lead to an increased need for computational resources, MCS is often used to evaluate the reliability of power systems. In order to alleviate this burden, an analytical method known as state space decomposition has previously been used to prune the state space that is sampled using MCS. This paper extends the state-of-the-art by proposing a novel algorithm known as intelligent state space pruning (ISSP). This algorithm leverages the intelligence of highly modified population based metaheuristic (PBM) algorithms including genetic algorithms (GA), particle swarm optimization (PSO), ant colony optimization (ACO), and artificial immune systems (AIS) to quickly, efficiently, and intelligently prune the state space that is used during MCS. The presented PBMs are modified using domain-specific knowledge to improve their performance and fine tune their intelligence. This new algorithm leads to reductions of up to 90% in total computation time and iterations required for convergence when compared to non-sequential MCS. Results are reported using the IEEE Reliability Test Systems (RTS79/MRTS). [Copyright &y& Elsevier]

The composite materials of the polymeric matrix reinforced with carbon fibre have an extensive industrial application as they provide light and resistant structures. However, in many products (automobiles, aircraft, etc.), the composite materials must be joined to other components manufactured with aluminium alloys. The use of structural adhesive to bond these materials may be a good alternative if a specific design of the adhesive joint is carried out by maximising its performance and reducing its limitations. In the current work, the end-notched flexure (ENF) fracture test is used to assess the mechanical behaviour of the adhesive joint to facilitate the choice of the best adhesive and surface treatment of the adherends. However, in industrial applications of a great technical requirement (where the safety of staff or property may be at risk), the former experimental results are not enough and must be complemented with methods that can provide additional guarantee for a suitable reliability. For this purpose, a statistic analysis of the obtained experimental data has been carried out by means of the application of a Weibull distribution, in order to propose the adhesive and surface treatment that best combines the mechanical performance and high reliability. At the end, we can conclude that the epoxy adhesive with sand-blasting treatment for the aluminium and the peel ply for the carbon fibre has the greatest reliability (more than 90% for loads until 900 N). [ABSTRACT FROM AUTHOR]

Abstract: Accelerated degradation testing (ADT) is a common approach in reliability prediction, especially for products with high reliability. However, oftentimes the laboratory condition of ADT is different from the field condition; thus, to predict field failure, one need to calibrate the prediction made by using ADT data. In this paper a Bayesian evaluation method is proposed to integrate the ADT data from laboratory with the failure data from field. Calibration factors are introduced to calibrate the difference between the lab and the field conditions so as to predict a product''s actual field reliability more accurately. The information fusion and statistical inference procedure are carried out through a Bayesian approach and Markov chain Monte Carlo methods. The proposed method is demonstrated by two examples and the sensitivity analysis to prior distribution assumption. [Copyright &y& Elsevier]

Due to the fact that there are more performance degradation data and less life data during development, producing, test and running, this paper provides a Bayes method to obtain the life distribution through fusing the two kinds of data, and the reliability assessment method based on performance parameters. At first, we obtain the noninformative prior distribution of the drift and volatity parameters of the Wiener process by using fisher information. And then, by using the degradation data, this paper gives the first posterior distribution based on the independent Gaussian increment, and the second posterior distribution based on the inverse life distribution by using the life data. The proposed approach is used to assess the reliability of spaceflight longlife product in the end. The results show that the new approach can improve the precision of assessment greatly. [ABSTRACT FROM AUTHOR]

In the condition settings of a power-frequency withstand voltage test for substation equipment, an approach based on insulation reliability evaluation using Weibull distribution is available. In this method, temporary overvoltage is evaluated using an ?independence model?. This ?independence model? assumes no remaining influence of voltage application (i.e. the model obeys the failure probability distribution starting at time 0 each time the voltage is applied). However, the authors have conducted insulation characteristics tests by applying a voltage multiple times at intervals and clarified that the influence of voltage application remains to a certain extent (i.e. the effect assumed in the ?accumulation model? appears) as well as the degree of influence depending on the conditions for oil-immersed transformer. The present paper proposes an evaluation method with the degree of influence of voltage application history taken into consideration. In the proposed method, the portions following an ?independence model? and an ?accumulation model? are respectively assumed and combined after multiplying the relevant coefficient representing the respective degrees of influence. According to the trial calculation based on the proposed method, the required withstand voltage decreased by several percentage points, while it was confirmed that the existing method is on the safer side as a means of evaluating the insulation reliability of temporary overvoltage. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, an efficient method is proposed for the exact reliability evaluation of k-out-of-n systems with identical components subject to phased-mission requirements and imperfect fault coverage. The system involves multiple, consecutive, and non-overlapping phases of operation, where the k values and failure time distributions of system components can change from phase to phase. The proposed method considers statistical dependencies of component states across phases as well as dynamics in system configuration and success criteria. It also considers the time-varying and phase-dependent failure distributions and associated cumulative damage effects for the system components. The proposed method is based on the total probability law, conditional probabilities and an efficient recursive formula to compute the overall mission reliability with the consideration of imperfect fault coverage. The main advantages of this method are that both its computational time and memory requirements are linear in terms of the system size, and it has no limitation on the type of time-to-failure distributions for the system components. Three examples are presented to illustrate the application and advantages of the proposed method. [Copyright &y& Elsevier]

Abstract: Soil–water characteristic curve (SWCC) is a crucial input for modeling the geotechnical problems with unsaturated soil. The accuracy of modeling relies on the assessment of the model parameter uncertainty. In this paper a Bayesian framework is presented to evaluate the updated probability density function (PDF) of the uncertain model parameters for SWCC. The Bayesian analysis is applied to derive the PDF of the model parameters in various forms of van Genuchten equation using the observed data of sand, sandy loam and silty loam. The analysis demonstrates that a 2-parameter model is sufficient for curve-fitting of the SWCC and the two model parameters are approximately statistically independent. Furthermore, the model parameters are influenced by the soil texture. Finally, an engineering example of the probabilistic slope stability analysis is used to illustrate the application of the reliability of SWCC. [Copyright &y& Elsevier]

Abstract: First, the artificial bee colony (ABC) algorithm was used to optimize the Kriging model. A typical example was given to validate a good function fitting performance of the ABC-optimized Kriging model. Next, a structural reliability optimization method was proposed on the basis of the Kriging surrogate model, combined with the artificial bee colony optimization method and penalty function method. A nonlinear limit-state function example was provided to validate the accuracy and efficiency of the hybrid algorithm by comparing the algorithm’s solution with the exact solution of the example. Finally, the proposed method was applied to earth slope reliability analysis using a commercial finite difference program to calculate the slope’s factor of safety. Comparison of the results between the proposed method and the other methods shows that the proposed algorithm is the most suitable for slope reliability analysis. [Copyright &y& Elsevier]

A wireless sensor network (WSN) is a distributed system composed of autonomous sensor nodes wireless connected and randomly scattered into a geographical area to cooperatively monitor physical or environmental conditions. Adequate techniques and strategies are required to manage a WSN in order it works properly, mainly focusing on its reliability. From the system reliability perspective, it is important to take into account that WSN nodes are usually battery-powered and the WSN reliability strongly depends on the power management at node level. Since standby power management policies are often applied at node level and, moreover, interferences among nodes may arise, a WSN can be considered as a system affected by dynamic-dependent behaviors among its components and therefore, the dynamic reliability approach can be applied. Static-structural interactions are specified by the WSN topology. Active-sleep standby policies and interferences due to wireless communications can be instead considered as dynamic aspects. Thus, in order to represent and to evaluate the WSN reliability dynamic reliability block diagrams are used in this paper. The proposed technique allows to overcome the limits of Markov models when considering nonlinear discharge processes, since such models cannot adequately represent the node aging process. In order to demonstrate the effectiveness of the DRBD technique in this context, we investigate some specific WSN network topologies, providing guidelines for their representation and evaluation. [ABSTRACT FROM AUTHOR]

This paper develops new models and concepts for incorporating the effect of protection system failures into power system reliability evaluation. The two types of protection failures, i.e., undesired-tripping mode and fail-to-operate mode, and their impact on reliability modeling are discussed. A complete Markov model for current-carrying components is established and its simplified form appropriately describes the overall reliability situation of individual components. Concepts of self-down state and induced-down state are introduced and used to build the composite unit model for quantitatively assessing the influence of protection failures on modeling system states. Finally, a Markov model of power systems with protection failures is proposed for system reliability evaluation. The proposed methodology is then illustrated in detail. [ABSTRACT FROM PUBLISHER]

Due to the lack of feeder corridors, the Chinese utility companies frequently choose the technique of putting multiple overhead feeders on a same tower (MFST) to meet the load demand in a heavy load area. In many situations, the distance among the feeders of MFST in an electrical distribution network (EDN) is usually too small to meet the requirements of safety regulation for repairing and maintenance. Therefore, when a fault occurs on a feeder of MFST, the other feeders have to be in a triggered passive outage (TPO) state to assist the repairing of the failed feeder. This paper presents a reliability evaluation algorithm for EDNs containing MFST using the section technique. The definition of TPO and the equivalent TPO rate and TPO duration are also proposed. Based on the TPO parameters and the section technique, the reliability evaluation algorithm containing the MFST can be obtained. Case studies on the modified RBTS-BUS6 and the EDNs of three districts in Dongguan city, China, show that the MFST has a significant impact on the EDN reliability and should be considered in the reliability evaluation. The results also show the effectiveness and applicability of the proposed approach. [ABSTRACT FROM PUBLISHER]

Appropriate wind speed modeling is an important requirement in the reliability evaluation of wind integrated electric power systems. This paper examines and illustrates the effects on the generating capacity adequacy indices of a small test system of using different wind speed modeling procedures in Monte Carlo simulation and analytical reliability assessment. Wind speed data for a number of different time periods at two quite diverse locations in Canada are used in the studies. Wind speed is represented using hourly observed data, hourly mean wind speed data, autoregressive moving average (ARMA) time series, moving average (MA) time series, Normal distribution, and Markov chain models. [ABSTRACT FROM PUBLISHER]

This paper proposes a reliability model for a superconducting fault current limiter (SFCL), which is a new alternative in limiting the fault current recently increasing in a network. An evaluation technique for distribution reliability that uses the improved failure rate of all protective devices in a network, depending on the location of the SFCL, is also proposed. As a result, it is expected that the SFCL makes the reliability of adjacent equipment on an existing network improve, and these changes are analyzed. In addition, in order to apply the effect of the intermittent output of renewable-energy sources, distribution reliability indices were redefined in this paper. Case studies verify that the SFCL is effective in reducing fault currents and improving distribution reliability. These effects are analyzed with respect to the location of the SFCL in a case study system. [ABSTRACT FROM AUTHOR]

Reliability is one of the key attributes of dependability and quality of service. Techniques and tools for reliability assessment are therefore required in order to evaluate and to predict system behavior. In many contexts, merely taking into account of static system structure is not adequate and it is necessary to take into account dynamic aspects and behaviors. The focus of the paper is to first identify and characterize such dynamic aspects in reliability, and therefore to provide an overview of the technique that can adequately evaluate them [ABSTRACT FROM AUTHOR]

This study describes an efficient technique for reliability assessment of composite power generation–transmission system. The state-space partitioning (SSP) method combines the advantages of the state enumeration method (SEM) and the Monte Carlo simulation (MCS). The SEM is quite effective at handling low-order contingencies that constitute a significant portion of the total state space. However, it is computationally inefficient for higher order contingencies. On the other hand, the MCS is very effective at sampling larger state spaces. With the SSP, the system state space is partitioned into two regions. The system states are first enumerated in descending probability order using the fast sorting technique (FST). Then the remainder of the state space is sampled using the MCS to catch low-probability states. Since the likelihood of encountering failed states in the non-enumerated part of the state space is higher than in the full state space, the simulation converges much faster than a direct MCS (DMCS). A comparison of SSP with the SEM and DMCS using IEEE reliability test system shows that the SSP considerably reduces the computational effort. The effectiveness of the proposed method is also demonstrated on a part of the China southern power grid. [ABSTRACT FROM AUTHOR]

The present work has as an objective to show an integral procedure for the realization of the technical inspections for shifts to machines and productive and energy teams in the factories of sugar raw Cubans using in a harmonic way (the maintenance system based on factors, the maintenance based on the reliability and supported in the experience, and the application of the simple and complex indexes of reliability) as decisive approach of the inspection method. [ABSTRACT FROM AUTHOR]

Increasing exploitation of wind energy requires the development of adequate models and techniques for reliability assessment of wind farms (WFs) and of electric power systems including wind energy conversion systems. A novel approach to WF modelling is investigated for reliability assessment, which is based on the universal generating functions. Such an approach combines the use of the z-transform and composition operators, allowing to account for all the factors affecting the WF performance. The results, both theoretical and numerical, of the case study, give evidence of the effectiveness of the proposed approach in terms of accuracy as well as of flexibility and efficiency of the solving algorithm. [ABSTRACT FROM AUTHOR]

In the present paper a technical analysis - the economics of the possibilities of production of Biodiesel on an industrial scale in the honey Company "Heriberto Duquesne" is made. The essential part of this article consists of the sizing of the equipment for the plant of obtaining of Biodiesel, from the residual sludge that contributes this honey Company. In addition three variants are analyzed from the technological point of view to carry out this process. For the last variant the calculation of the optimal number of equipment considers to obtain the reliability of the process, aspect that guarantees the continuity of the same one. Finally an analysis is made previously from the economic point of view of the different treated variants, which demonstrates that the third variant is most feasible as much from the technological point of view like economic. An analysis to sensitivity for the variation of the price of the byproduct is made in addition that demonstrates that the selected variant is feasible for prices greater than 6,26 $/Kg. [ABSTRACT FROM AUTHOR]

This paper analyses the influence of measurement uncertainty to the decision-making model, where possible values are distributed normally and are limited by predefined limit values. While analysing evaluation of uncertainty in vibration monitoring systems, the latter due to the features and nature of the measurement process are distinguished into two main types: permanently installed systems and periodical vibration monitoring systems. The uncertainty model for these two different monitoring systems is also provided. [Copyright &y& Elsevier]

Environmental awareness and legislative pressures have made manufacturers responsible for the take-back and end-of-life treatment of their products. To competitively exploit these products, one option is to incorporate used components in “new” or remanufactured products. However, this option is partly limited by a firm''s ability to assess the reliability of used components. A comprehensive two-step approach is proposed. The first stage phase statistically analyzes the behavior of components for reuse. A well-known reliability assessment method, the Weibull analysis, is applied to the time-to-failure data to assess the mean life of components. In the second phase, the degradation and condition monitoring data are analyzed by developing an artificial neural network (ANN) model. The advantages of this approach over traditional approaches employing multiple regression analysis are highlighted with empirical data from a consumer product. Finally, the Weibull analysis and the ANN model are then integrated to assess the remaining useful life of components for reuse. This is a critical advance in sustainable management of supply chains since it allows for a better understanding of not only service requirements of product, but the remaining life in a product and hence its suitability for reuse or remanufacture. Future work should assess: (1) reduction in downtime of process equipment through the implementation of this technique as a means to better manage preventative maintenance; (2) reduce field failure of remanufactured product; (3) selling-service strategy through implementation of the proposed methodology. [Copyright &y& Elsevier]

An approach to analyze the seismic reliability of water distribution networks by combining a hydraulic analysis with a first‐order reliability method is proposed. The hydraulic analysis method for normal conditions is modified to accommodate the special conditions necessary to perform a seismic hydraulic analysis. To calculate the leakage area and leaking flow of the pipelines, a new leakage model is presented. [ABSTRACT FROM PUBLISHER]

Abstract: The reference IFMIF target design is based on the use of a replaceable backplate. The backplate is the component most heavily exposed to the high neutron flux, and so its lifetime is expected to be very short. Moreover, the high activation levels prevent direct hands-on access to the target components and thus the maintenance work of such target facility has to be performed remotely. A prototype of the replaceable backplate, based on so-called “ bayonet concept”, has been fabricated and validated and its suitability for the remote handling maintainability has been demonstrated. Furthermore, a cycle of repetitive trials of backplate replacement were executed to evaluate the reliability of the prototype including rescue procedures. This paper outlines the remote handling activities, the reliability trials carried out and the development of the rescue procedures for the IFMIF target replaceable backplate. The overall results of the activities are also reported. [Copyright &y& Elsevier]

Examines the relationship between data analysis and reliability assessment. Methods of data analysis; Illustration of degradation data; Implementation of the use of standard statistical method for degradation analysis.

Provides information on a study which proposed an algorithm based on Monte-Carlo simulation method for composite system reliability evaluation. Main idea of the algorithm; Rules of failure effect analysis (FEA); Conclusions of the study.

Reports on a study to systematically assess the reliability of high-strength concrete (HSC) columns designed according to American Concrete Institute (ACI) Code provisions. Reliability analysis; Effect of amount of confining steel; Effect of concrete compressive strength and slenderness ratio; Effect of amount of longitudinal steel and mean load ratio; Influential factors on reliability.