scholarly journals Reliability-Based Preventive Maintenance Strategy of Truck Unloading Systems

2020 ◽  
Vol 10 (19) ◽  
pp. 6957
Author(s):  
Awsan Mohammed ◽  
Ahmed Ghaithan ◽  
Mashel Al-Saleh ◽  
Khalaf Al-Ofi
Keyword(s):  
System Reliability ◽  
Preventive Maintenance ◽  
Failure Modes ◽  
Reliability Function ◽  
Petroleum Products ◽  
Maintenance Strategy ◽  
Mean Time Between Failures ◽  
Time Period ◽  
Critical Components ◽  
One Year

The unloading of petroleum products is a complex and potentially dangerous operation since the unloading system contains complex interdependency components. Any failures in one of its components lead to a cut in the petroleum supply chain. Therefore, it is important to assess and evaluate the reliability of the unloading system in order to improve its availability. In this context, this paper presents the operation philosophy of the truck unloading system, failure modes of the components within the system, and a bottom-up approach to analyze the reliability of the system. In addition, it provides reliability data, such as failure rates, and mean time between failures of the system components. Furthermore, the reliability of the whole system was calculated and is presented for different time periods. The critical components, which are major contributors towards the system reliability, were identified. To enhance the system reliability, a reliability-based preventive maintenance strategy for the critical components was implemented. In addition, the preventive maintenance scheduling was identified based on the reliability plots of the unloading system. The best schedule for preventive maintenance of the system was determined based on the reliability function to be every 45 days for maintaining the system reliability above 0.9. Findings reveal that the reliability of the unloading system was significantly improved. For instance, the system reliability at one year improved by 80%, and this ratio increased dramatically as the time period increased.

scholarly journals A New Analytic Method of Multistate Single-component System Reliability Model

2018 ◽  
Vol 175 ◽  
pp. 03058
Author(s):  
Xie Jingwei ◽  
Huang Peng ◽  
Liu Gang
Keyword(s):  
System Reliability ◽  
Preventive Maintenance ◽  
Single Component ◽  
Matrix Analysis ◽  
Phase Type Distribution ◽  
Numerical Application ◽  
Reliability Modeling ◽  
Component System ◽  
Mean Time Between Failures ◽  
Single Component System

For the reliability modeling of multistate single-component system, single maintenance bench provides the preventive maintenance and alternative maintenance services on the basis of system performance level following the stochastic detection strategy. Phase-type distribution is employed in place of exponential distribution and other typical distributions to describe the stochastic time variable in the reliability modeling process in a unified manner. Through matrix analysis, the analytic expressions for reliability indicators including system steady-state availability, mean time between failures (MTBF) and failure rate of system are obtained. A numerical application is presented to verify the applicability of the model and demonstrate the influence of preventive maintenance threshold and preventive maintenance rate on system reliability.

Enhancing performance of maintenance in solar power plant

2019 ◽  
Vol 26 (4) ◽  
pp. 575-591
Author(s):  
Jittra Rukijkanpanich ◽  
Mathurot Mingmongkol
Keyword(s):  
Power Plant ◽  
Failure Modes ◽  
Solar Power ◽  
Electrical Equipment ◽  
First Year ◽  
Solar Power Plant ◽  
Maintenance Strategy ◽  
Content Type ◽  
One Year ◽  
Practical Implications

Purpose The purpose of this paper is to enhance the performance of maintenance in a solar power plant by implementing the proactive maintenance (PaM) strategy, measured by the availability and the total maintenance workload. Design/methodology/approach The prior maintenance strategy was reviewed, and then the strategy was adjusted to focus on PaM. Failure modes and effects analysis (FMEA) was a tool for analyzing the severity and occurrence of the failure modes and effects. Then, the Why‒Why analysis was used for investigating the root causes of failures. The countermeasures were drawn, and the preventive maintenance (PM) plan was revised and carried out. The total maintenance, the PaM and reactive maintenance workload, was obtained, and then the improvements were determined. The values of availability were also obtained. Findings Previously, the appeared maintenance strategy was not clearly defined. It seemed to have reactive maintenance coupled with PM; it was checked once a year, and corrective actions were made when something wrong was found. Then the management team observed an increase in the reactive maintenance workload, whereas the values of availability were not consistent and tended to drop. After implementing the new maintenance strategy, PaM, the total maintenance workload decreased 14 percent in one year. The average availability of the solar power plant improved from 0.9943 to 0.9969, and the values of availability had better consistency. Practical implications The PaM can be applied to solar power plant without limiting the prior maintenance strategy and the complexity of production or machinery. The solar power plant is a quite simple production, and most machines consist of electrical equipment and electrical circuits. The PaM supports to analyze the failure modes, the consequence of the failure events and failure effects, and to decide what should be done. Importantly, PaM can reduce total maintenance workload while the value of availability is higher and consistent. Originality/value This paper states how to successfully implement the PaM for the solar power plant. Previously, the plant did not have a clearly defined maintenance strategy; it was checked once a year, and it was corrected when abnormalities were detected. The PaM strategy provides tools and processes for failures and effects analysis. Although there was a more workload of PM, the total maintenance workload decreased, even in the first year.

Reliability Analysis on the Chassis Hydraulic System in Hydraulic Loader

2013 ◽  
Vol 299 ◽  
pp. 35-37
Author(s):  
Xiao Gang Li ◽  
Wei Han Wang ◽  
Wei Fang Zhang ◽  
Yu Fan Wang
Keyword(s):  
Hydraulic System ◽  
Failure Modes ◽  
Matrix Analysis ◽  
Construction Site ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
High Efficient ◽  
Critical Components ◽  
Major Equipment ◽  
Mean Time

Hydraulic loader is a major equipment for the airport engineering, the high efficient excavation is closely related to the reliability of equipment. Due to severe environment in the construction site, the chassis hydraulic system has high failure rate in the loader. Based on the criticality matrix analysis, some fatal failure modes were traced, including the leakage of motor, the pollution of hydraulic oil, the suction air of pump. Through the reliability prediction analysis, the estimated reliability of the chassis hydraulic system is 0.27, and mean time between failures of the system is 183h, in addition, critical components in the system are also determined. The above result could be used as reference for the optimization designing.

scholarly journals One Year of the COVID-19 Pandemic in Galicia: A Global View of Age-Group Statistics during Three Waves

2021 ◽  
Vol 18 (10) ◽  
pp. 5104
Author(s):  
Iván Area ◽  
Henrique Lorenzo ◽  
Pedro J. Marcos ◽  
Juan J. Nieto
Keyword(s):  
Intensive Care Unit ◽  
Hospital Admissions ◽  
Age Groups ◽  
Age Group ◽  
Nw Spain ◽  
The Past ◽  
Global View ◽  
Time Period ◽  
Key Variables ◽  
One Year

In this work we look at the past in order to analyze four key variables after one year of the COVID-19 pandemic in Galicia (NW Spain): new infected, hospital admissions, intensive care unit admissions and deceased. The analysis is presented by age group, comparing at each stage the percentage of the corresponding group with its representation in the society. The time period analyzed covers 1 March 2020 to 1 April 2021, and includes the influence of the B.1.1.7 lineage of COVID-19 which in April 2021 was behind 90% of new cases in Galicia. It is numerically shown how the pandemic affects the age groups 80+, 70+ and 60+, and therefore we give information about how the vaccination process could be scheduled and hints at why the pandemic had different effects in different territories.

Survival With Respect to Morphology in Pulmonary Atresia and Intact Ventricular Septum in Sweden

2021 ◽  
Vol 12 (1) ◽  
pp. 27-34
Author(s):  
Stina Manhem ◽  
Katarina Hanséus ◽  
Håkan Berggren ◽  
Britt-Marie Ekman-Joelsson
Keyword(s):  
Pulmonary Atresia ◽  
Early Time ◽  
Ventricular Septum ◽  
Intact Ventricular Septum ◽  
Early Group ◽  
Time Period ◽  
Medical Reports ◽  
One Year ◽  
Survival Risk ◽  
Late Group

Background: Patients born with pulmonary atresia and intact ventricular septum represent a challenge to pediatric cardiologists. Our objective was to study changes in survival with respect to morphology in all children born with pulmonary atresia and intact ventricular septum in Sweden during 36 years. Methods: A retrospective, descriptive study based on medical reports and echocardiographic examinations consisting of those born between 1980 and 1998 (early group) and those born between 1999 and 2016 (late group). Results: The cohort consists of 171 patients (early group, n = 86 and late group, n = 85) yielding an incidence of 4.35 and 4.46 per 100,000 live births, respectively. One-year survival in the early group was 76% compared to 92% in the late group ( P = .0004). For patients with membranous atresia, one-year survival increased from 78% to 98%, and for muscular pulmonary atresia, from 68% to 85%. In patients with muscular pulmonary atresia and ventriculocoronary arterial communications, there was no significant increase in survival. Risk factors for death were being born in the early time period hazard ratio (HR), 6; 95% CI (2.33-14.28) P = .0002, low birth weight HR, 1.26; 95% CI (1.14-1.4) P < .0001 and having muscular pulmonary atresia HR, 3.74; 95% CI (1.71-8.19) P = .0010. Conclusion: The incidence of pulmonary atresia and intact ventricular septum remained unchanged during the study period. Survival has improved, especially for patients with membranous pulmonary atresia, while being born with muscular pulmonary atresia is still a risk factor for death. To further improve survival, greater focus on patients with muscular pulmonary atresia and ventriculocoronary arterial communications is required.

scholarly journals Dynamic Effect of Perfect Preventive Maintenance on System Reliability and Cost Using HiP-HOPS

2010 ◽  
Vol 43 (17) ◽  
pp. 204-209 ◽  
Author(s):  
Shawulu H. Nggada ◽  
David J. Parker ◽  
Yiannis I. Papadopoulos
Keyword(s):  
System Reliability ◽  
Preventive Maintenance ◽  
Dynamic Effect

Algorithms and Formulae for Conversion Between System Signatures and Reliability Functions

2015 ◽  
Vol 52 (02) ◽  
pp. 490-507
Author(s):  
Jean-Luc Marichal
Keyword(s):  
System Reliability ◽  
Reliability Function ◽  
Efficient Algorithms ◽  
System Designs ◽  
Independent And Identically Distributed

The concept of a signature is a useful tool in the analysis of semicoherent systems with continuous, and independent and identically distributed component lifetimes, especially for the comparison of different system designs and the computation of the system reliability. For such systems, we provide conversion formulae between the signature and the reliability function through the corresponding vector of dominations and we derive efficient algorithms for the computation of any of these concepts from any other. We also show how the signature can be easily computed from the reliability function via basic manipulations such as differentiation, coefficient extraction, and integration.

Criticality Analysis for Maintenance Purposes of Platform Supply Vessels in Remote Areas

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
A. Marhaug ◽  
A. Barabadi ◽  
E. Stagrum ◽  
K. Karlsen ◽  
A. Olsen ◽  
...  
Keyword(s):  
Failure Modes ◽  
Oil And Gas Industry ◽  
Spare Parts ◽  
Acceptable Level ◽  
Component Level ◽  
Screening Process ◽  
Essential Information ◽  
Remote Areas ◽  
Critical Components ◽  
Criticality Analysis

The oil and gas industry is pushing toward new unexplored remote areas, potentially rich in resources but with limited industry presence, infrastructure, and emergency preparedness. Maintenance support is very important and challenging in such remote areas. A platform supply vessel (PSV) is an essential part of maintenance support. Hence, the acceptable level of its availability performance is high. Identification of critical components of the PSV provides essential information for optimizing maintenance management, defining a spare parts strategy, estimating competence needs for PSV operation, and achieving the acceptable level of availability performance. Currently, there are no standards or guidelines for the criticality analysis of PSVs for maintenance purposes. In this paper, a methodology for the identification of the critical components of PSVs has been developed, based on the available standard. It is a systematic screening process. The method considers functional redundancy and the consequences of loss of function as criticality criteria at the main and subfunction levels. Furthermore, at the component level, risk tools such as failure modes, effects and criticality analysis (FMECA), and fault tree analysis (FTA) will be applied in order to identify the most critical components. Moreover, the application of the proposed approach will be illustrated by a real case study.

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