Inspecting Briquette Machine with Different Faults

2020 ◽  
Vol 13 ◽  
Author(s):  
Divesh Garg ◽  
Reena Garg ◽  
Vanita Garg
Keyword(s):  
Failure Rate ◽  
Rate Increase ◽  
Practical Importance ◽  
System Failure ◽  
Regenerative Point ◽  
Semi Markov Process ◽  
Major Fault ◽  
Environment Study ◽  
Burning Coal ◽  
Mean Time

Background: A briquette machine can be considered very useful in modern times as the need of energy consumption is increasing rapidly. Considering the harm to environment, study of briquette machine is the need of present times. In this paper, the operative unit is considered as briquette machine also known as bio-coal which is used for agroforestry waste. Objective: A single operative unit has been analyzed stochastically. The inspection of breakdown of a unit reveals the feasibility of the unit under the supervision of either ordinary or expert repairmen. Two types of fault are revealed by the repairmen either minor or major fault. Minor faults are repaired immediately by the same repairmen but whenever major fault held, the machine’s fault will be handled by expert person. Method: It is assumed that the repair needs no modification once served. Availability, Mean-time for system failure, and profits are analyzed by utilizing the Regenerative point graphical technique and semi-Markov process. Result: Study reveals that the Mean-time for system failure of the system model go on decreasing as failure rate increase and availability goes on decreasing as failure-rate increase. Moreover, the study shows that the systems profit goes down on increase of Failure-rate. Conclusion: Findings of the study supports the hypothesis that the limits of failure/repair/inspection rate will surely have effective profitability. Moreover, it is found that the utility of scale of operation can easily be derived. The practical importance of biomass briquettes for burning coal or wood is very well appreciated.

Analysis of discrete-time semi-Markov model for a two-unit warm standby system subject to degradation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Neama Temraz
Keyword(s):  
Markov Model ◽  
Weibull Distribution ◽  
Discrete Time ◽  
Content Type ◽  
Regenerative Point ◽  
Semi Markov Process ◽  
Regenerative Point Technique ◽  
The Mathematical Model ◽  
Mean Time ◽  
Warm Standby

PurposeThe present paper analyzed a model consisting of one unit with a warm standby unit where the main unit has three states: up, degraded and down.Design/methodology/approachThe semi-Markov model under the regenerative method is used to construct the mathematical model for the system.FindingsThe effectiveness measures of the system are discussed such as availability, reliability, steady-state availability and mean time to system failure. The life and repair times of the system units are assumed to be discrete follow discrete Weibull distribution. Also, the parameters of the discrete Weibull distribution are assumed to be fuzzy with bell-shaped membership function. An application is introduced to show the results obtained for the system and the profit of the presented model.Originality/valueRarely papers in literature treated the topic of the discrete-time semi-Markov process using a regenerative point technique.

scholarly journals Performance Analysis of a Rod Breakdown System

2018 ◽  
Vol 7 (3.4) ◽  
pp. 243
Author(s):  
S Z Taj ◽  
S M Rizwan ◽  
B M Alkali ◽  
D K Harrison ◽  
G Taneja
Keyword(s):  
Performance Analysis ◽  
Preventive Maintenance ◽  
System Failure ◽  
Performance Indices ◽  
System Availability ◽  
Cooling Period ◽  
Regenerative Point ◽  
Semi Markov Processes ◽  
Mean Time ◽  
Two Machines

The paper presents performance analysis of a rod breakdown system consisting of two machines operating in parallel. Ten years maintenance data of the system depicts three maintenance practices: repair, major preventive maintenance and minor preventive maintenance. Machines are repaired on normal failures, whereas major/minor preventive maintenance is carried out at scheduled basis. The machines are queued for major preventive maintenance. An operative machine requires a cooling period of half hour before undergoing major preventive maintenance. Repair is prioritized over major preventive maintenance. The system is analysed using semi-Markov processes and regenerative point techniques. Performance indices namely mean time to system failure, system availability, no. of system repairs and busy period of the repairman are obtained. Simulated results are presented to demonstrate the effect of varying failure/repair rates on the system performance.  

Reliability Analysis of Cold Standby Parallel System Possessing Failure And Repair Rate Under Geometric Distribution

2019 ◽  
Vol 13 ◽  
Author(s):  
Jasdev Bhatti ◽  
Mohit Kumar Kakkar
Keyword(s):  
Failure Rate ◽  
Geometric Distribution ◽  
Discrete Distribution ◽  
Maintenance Cost ◽  
Discrete Problem ◽  
New Techniques ◽  
Testing Strategies ◽  
Cold Standby ◽  
Mean Time ◽  
Iteration Technique

Background and Aim: With an increase in demands about reliability of industrial machines following continuous or discrete distribution, the important thing to be noticed is that in all previous researches where systems are having more than one failure no iteration technique has been studied to separate the failed unit on basis of its failure. Therefore, aim of our paper is to analyze the real industrial discrete problem following cold standby units arranged in parallel manner with newly concept of inspection procedure for failed units to inspect the exact failure and being communicator to the repairman for repairing exact failed part of unit for saving time and maintenance cost. Methods: The geometric distribution and regenerative techniques had been applied for calculating different reliability measures like mean time to system failure, availability of a system, inspection, repair and failed time of unit. Results: Graphical and analytical study had also been done to analyze the increasing/decreasing behavior of profit function w.r.t repair and failure rate. The system responded properly in fulfilling his basic needs. Conclusion: The calculated value of all reliability parameter is helpful for studying any other models following same concept under different environmental conditions. Thus, it concluded that, reliability increases/decreases with increase in repair/failure rate. Also, the evaluated results by this paper provides the better reliability testing strategies that helps to develop new techniques which leads to increase the effectiveness of system.

Gas system failure rate

2005 ◽  
Vol 59 (3) ◽  
pp. 339-364
Author(s):  
T. van der Hoeven ◽  
A. G. M. Steerneman
Keyword(s):  
Failure Rate ◽  
System Failure ◽  
Gas System

scholarly journals Effect of Grid Instability on Power Generation System's Reliability

2020 ◽  
pp. 27-37
Author(s):  
Joseph Benedict Bassey ◽  
Isaac F. Odesola
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Failure Rate ◽  
System Reliability ◽  
Power Distribution ◽  
Power Plants ◽  
Time To Failure ◽  
Generation System ◽  
Reliability Indices ◽  
Mean Time

Aims: Reliability assessment of power generation system may be performed with the concept of system adequacy, security or both. Grid being a major component in the power distribution chain is seen to have some influence on the state of the generation system reliability because of the perturbation that may arise from it. In this study, the generation system reliability is evaluated using both the system adequacy and security concept. Study Design: To capture the system security problems attributed to grid disturbance, the generation system is structured into two component systems (1 - generation component and 2 - transmission component) with a series arrangement. Methodology: The reliability indices such as, mean time to failure, mean time to repair, failure rate and repair rate are assessed on component bases and with respect to the entire generation system. Results: The effect of failure rate of the transmission component on the entire generation system failure rate was evaluated as 66.25%, 55.55%, 33.33%, 55.00% and 35.72% in year 2013, 2014, 2017 2018 and 2019 respectively for FIPL Power Plant and 52.94%, 82.35%, 61.38% and 100% effect was evaluated in the year 2016, 2017, 2018 and 2019 respectively for GT5 of Omoku Power Plant. Conclusion: These results showed that there is a significant influence of grid disturbances on the reliability state of the two gas turbine power plants in Nigeria. Measures on possible reliability state improvement of the power generation systems were suggested to include training and retraining of technical personnel on the management of major equipment in the generation and transmission stations. 

Research on Spurious Trip of 1oo2 Safety Instruments of Petrochemical Installation with Repair Considered

2010 ◽  
Vol 118-120 ◽  
pp. 596-600
Author(s):  
Jian Xin Zhu ◽  
Xue Dong Chen ◽  
Shi Yi Bao
Keyword(s):  
Failure Rate ◽  
System Reliability ◽  
Repairable System ◽  
Time To Failure ◽  
Redundant System ◽  
Common Cause ◽  
System A ◽  
Definition Of ◽  
Mean Time ◽  
Complex Influence

An innovative nuisance trip calculation method based on Markov model was proposed in this paper which was used to evaluate the effect of repairment on system reliability. By analysis of the availabilities of classic 1 out of 2 (1oo2) repairable system, a new definition of spurious trip was put forwarded where online repair was considered. Compared with the benefits obtained by online repairment, the repair-caused-nuisance-trip was analyzed in this paper. Numerical calculation revealed that the online repair is helpful for anti-spurious trip in 1oo2 redundant system. Dangerous failures, if not repaired or cannot be online fixed, have complex influence on system reliability. The dangerous failure is sometimes benefit for anti-spurious performance if it is not repaired. But Mean Time To Failure Spurious (MTTFs) reduces with the increase of dangerous failure provided that dangerous failure rate is bigger than safe failure rate. Meanwhile, the finding that common cause can reduce the chance of nuisance trip was also proposed in this paper, though the influence is too small to be neglected.

scholarly journals Survival and failure trends of cerebrospinal fluid shunts with distal slit valves: comparative study and literature review

2020 ◽  
Vol 25 (3) ◽  
pp. 209-216
Author(s):  
Jeremy S. Wetzel ◽  
Alex D. Waldman ◽  
Pavlos Texakalidis ◽  
Bryan Buster ◽  
Sheila R. Eshraghi ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Failure Rate ◽  
Csf Shunt ◽  
Time To Failure ◽  
Survival Curves ◽  
Mean Time To Failure ◽  
Distal Catheter ◽  
Catheter Obstruction ◽  
Shunt Survival ◽  
Mean Time

OBJECTIVEThe malfunction rates of and trends in various cerebrospinal fluid (CSF) shunt designs have been widely studied, but one area that has received little attention is the comparison of the peritoneal distal slit valve (DSV) shunt to other conventional valve (CV) type shunts. The literature that does exist comes from older case series that provide only indirect comparisons, and the conclusions are mixed. Here, the authors provide a direct comparison of the overall survival and failure trends of DSV shunts to those of other valve type shunts.METHODSThree hundred seventy-two new CSF shunts were placed in pediatric patients at the authors’ institution between January 2011 and December 2015. Only ventriculoperitoneal (VP) shunts were eligible for study inclusion. Ventriculoatrial, lumboperitoneal, cystoperitoneal, subdural-peritoneal, and spinal shunts were all excluded. Rates and patterns of shunt malfunction were compared, and survival curves were generated. Patterns of failure were categorized as proximal failure, distal failure, simultaneous proximal and distal (proximal+distal) failure, removal for infection, externalization for abdominal pseudocyst, and addition of a ventricular catheter for loculated hydrocephalus.RESULTSA total of 232 VP shunts were included in the final analysis, 115 DSV shunts and 117 CV shunts. There was no difference in the overall failure rate or time to failure between the two groups, and the follow-up period was statistically similar between the groups. The DSV group had a failure rate of 54% and a mean time to failure of 17.8 months. The CV group had a failure rate of 50% (p = 0.50) and a mean time to failure of 18.5 months (p = 0.56). The overall shunt survival curves for these two groups were similar; however, the location of failure was significantly different between the two groups. Shunts with DSVs had proportionately more distal failures than the CV group (34% vs 14%, respectively, p = 0.009). DSV shunts were also found to have proximal+distal catheter occlusions more frequently than CV shunts (23% vs 5%, respectively, p = 0.005). CV shunts were found to have significantly more proximal failures than the DSV shunts (53% vs 27%, p = 0.028). However, the only failure type that carried a statistically significant adjusted hazard ratio in a multivariate analysis was proximal+distal catheter obstruction (CV vs DSV shunt: HR 0.21, 95% CI 0.05–0.81).CONCLUSIONSThere appears to be a difference in the location of catheter obstruction leading to the malfunction of shunts with DSVs compared to shunts with CVs; however, overall shunt survival is similar between the two. These failure types are also affected by other factors such etiology of hydrocephalus and endoscope use. The implications of these findings are unclear, and this topic warrants further investigation.

On operation termination for degrading systems with two types of failures

2018 ◽  
Vol 233 (3) ◽  
pp. 419-426 ◽  
Author(s):  
Maxim Finkelstein ◽  
Gregory Levitin ◽  
Oleg A Stepanov
Keyword(s):  
Failure Rate ◽  
Cost Effective ◽  
System Failure ◽  
Minimal Repair ◽  
System Operation ◽  
Numerical Examples ◽  
Relevant Case ◽  
The One ◽  
Combined Strategy

When a failure occurring during a system operation can result in considerable penalties, it can be more cost-effective to terminate the operation at some time avoiding the risk of future failures. This strategy can be relevant for aging systems, for example, when the system failure rate is increasing. The paper analyzes three strategies of termination for systems with major and minor failures. A major failure automatically terminates the operation, whereas the minor failures are minimally repaired. We show that the age-based strategy outperforms the one with termination after the mth minimal repair. The combined strategy when the termination is performed at time t or upon the mth minimal repair, whichever comes first, is also considered. The emphasis for the latter setting is on the practically relevant case when the number of possible minimal repairs is limited. Numerical examples illustrating the findings are presented.

RELIABILITY MEASURES OF A COLD STANDBY SYSTEM WITH PREVENTIVE MAINTENANCE AND REPAIR

2013 ◽  
Vol 20 (06) ◽  
pp. 1350022 ◽  
Author(s):  
S. C. MALIK ◽  
SUDESH K. BARAK
Keyword(s):  
Preventive Maintenance ◽  
Failure Time ◽  
Reliability Measures ◽  
Maintenance And Repair ◽  
Regenerative Point ◽  
Cold Standby ◽  
Semi Markov Process ◽  
Standby System ◽  
Regenerative Point Technique ◽  
Negative Exponential

The purpose of the present study is to determine reliability measures of a two-unit cold standby system with preventive maintenance and repair. The units are identical in nature subject to constant failure from normal mode. Preventive maintenance of the operative unit is carried out after a pre-specific time "t" up to which no failure occurs. However, repair of the unit is done at its failure. The unit works as new after repair and preventive maintenance. The switch devices are perfect. The distributions of failure time and the time by which unit undergoes for preventive maintenance are taken as negative exponential while that of preventive maintenance and repair times are assumed as arbitrary with different probability density functions. The random variables associated with failure, preventive maintenance and repair times are statistically independent. The semi-Markov process and regenerative point technique are adopted to derive the expressions for system performance measures in steady state. The graphical behavior of MTSF, availability and profit function have been observed with respect to preventive maintenance rate for particular values of other parameters and costs.

Sign in / Sign up

Export Citation Format

Share Document