scholarly journals A Dynamic Methodology for Setting Up Inspection Time Intervals in Conditional Preventive Maintenance

2021 ◽  
Vol 11 (18) ◽  
pp. 8715
Author(s):  
Rui Assis ◽  
Pedro Carmona Marques
Keyword(s):  
Preventive Maintenance ◽  
Probability Function ◽  
Time Windows ◽  
Inspection Time ◽  
Test Results ◽  
Time Intervals ◽  
False Negatives ◽  
Wear And Tear ◽  
Potential Failure ◽  
Over Time

In periodic condition monitoring, the main problem lies in determining the inspection time intervals. This paper presents a new method for setting an optimum calendar to inspect a critical component that fails due to wear and tear as described by a Weibull probability function. By considering a set of inspection intervals, such that reliability between every two inspections is kept equal or below a pre-set threshold while keeping the total costs of inspection, degraded production, consequences of failure, and repair to a minimum. The resulting calendar may be adjusted dynamically over time as inspections take place and test results are found to be negative, by considering the inspector’s confidence in the test and the likelihood of the method’s yielding false negatives. Consequently, the method becomes self-adjustable as it returns a new calendar after the observations of each test are known and properly interpreted. There are several studies that deal with this issue, but none addresses the concept of safe and unsafe time windows which results from merging two other concepts: descendant inspection time intervals and the time delay between a potential failure and a functional failure (the P–F period).

scholarly journals Study on viscosity modification of human and formula milk for infants with dysphagia

Revista CEFAC ◽  
2017 ◽  
Vol 19 (5) ◽  
pp. 683-689 ◽  
Author(s):  
Mariangela Bartha de Mattos Almeida ◽  
Saint Clair Gomes Júnior ◽  
Jonas Borges da Silva ◽  
Danielle Aparecida da Silva ◽  
Maria Elisabeth Lopes Moreira
Keyword(s):  
Human Milk ◽  
Infant Formula ◽  
Therapeutic Option ◽  
Feeding Time ◽  
Test Results ◽  
Time Intervals ◽  
Formula Milk ◽  
Thickening Agent ◽  
Viscosity Modification ◽  
Over Time

ABSTRACT Purpose: to analyze the modification of the viscosity of human milk and infant formula. Methods: three studies were performed to assess the viscosity and effect of time on infant formula with a thickener, at concentrations of 2, 3, and 5%, as well as raw and pasteurized human milk at concentrations of 2, 3, 5, and 7% at 37ºC, for 60 minutes. Rice cereal was used as a thickening agent. The viscosity was evaluated using a Ford Cup-type viscometer, and the samples were analyzed at 20-minute intervals. Significant differences were assessed using the ANOVA test. Results: no significant differences in viscosity were observed over time in concentrations of 2, 3, and 5%. There was a difference in the viscosity between human milk and infant formula, in concentrations of 2% and 5%, 2% and 7%, 3% and 5%, and 3% and 7%, independently of the time intervals evaluated. Conclusion: the findings of this study demonstrate the need for different concentrations of the thickening agent for human milk and infant formula. Rice cereal is a suitable therapeutic option for newborns presented with dysphagia in concentrations of 2, 3, 5, and 7%, due to its effect on the viscosity and flow reduction, provided that the feeding time is considered.

Test of Solidification Characteristics of Grouting and the Effect on Strata Deformation in Shield Tunnelling

2012 ◽  
Vol 568 ◽  
pp. 80-84
Author(s):  
Xiao Chun Zhong ◽  
Wei Ke Qin ◽  
Hai Wang
Keyword(s):  
Numerical Model ◽  
Rigid Body ◽  
Active Control ◽  
Calculation Method ◽  
Civil Engineering ◽  
Test Results ◽  
Shield Tunneling ◽  
Shield Tunnelling ◽  
Strata Deformation ◽  
Over Time

Back-fill Grouting is a key procedure for the active control of strata settlement during shield tunnelling in civil engineering. The paper studies the stress - strain characteristics of grouting and the state of grout, which changes from liquid to solid over time and is simulated by variable rigid body. The model of flowing state are divided in four phases from liquid-plastic to rigid state. The paper establish a numerical model of shield tunnelling in civil engineering with the consideration of characteristics of grout deformation, and has analyzed law of strata settlement. The test results show that the calculation method can well accord with the four stages of strata deformation, and can more accurately reflect the process of strata deformation caused by shield tunneling.

scholarly journals Male and Female Partner-Caregivers’ Burden: Does It Get Worse Over Time?

2018 ◽  
Vol 59 (6) ◽  
pp. 1103-1111 ◽  
Author(s):  
Joukje C Swinkels ◽  
Marjolein I Broese van Groenou ◽  
Alice de Boer ◽  
Theo G van Tilburg
Keyword(s):  
Caregiver Burden ◽  
Process Model ◽  
Female Partner ◽  
General View ◽  
Data Set ◽  
Change Over Time ◽  
Men And Women ◽  
Wear And Tear ◽  
The Impact ◽  
Over Time

Abstract Background and Objectives The general view is that partner-caregiver burden increases over time but findings are inconsistent. Moreover, the pathways underlying caregiver burden may differ between men and women. This study examines to what degree and why partner-caregiver burden changes over time. It adopts Pearlin’s Caregiver Stress Process Model, as it is expected that higher primary and secondary stressors will increase burden and larger amounts of resources will lower burden. Yet, the impact of stressors and resources may change over time. The wear-and-tear model predicts an increase of burden due to a stronger impact of stressors and lower impact of resources over time. Alternatively, the adaptation model predicts a decrease of burden due to a lower impact of stressors and higher impact of resources over time. Research Design and Methods We used 2 observations with a 1-year interval of 279 male and 443 female partner-caregivers, derived from the Netherlands Older Persons and Informal Caregivers Survey Minimum Data Set. We applied multilevel regression analysis, stratified by gender. Results Adjusted for all predictors, caregiver burden increased over time for both men and women. For female caregivers, the impact of poor spousal health on burden increased and the impact of fulfillment decreased over time. Among male caregivers, the impact of predictors did not change over time. Discussion and Implications The increase of burden over time supports the wear-and-tear model, in particular for women. This study highlights the need for gender-specific interventions that are focused on enabling older partners to be better prepared for long-term partner-care.

scholarly journals Measures for Resource Saving for Diesel Locomotives

2018 ◽  
Vol 7 (4.3) ◽  
pp. 152 ◽  
Author(s):  
Dmytro Aulin ◽  
Artem Zinkivskyi ◽  
Oleksandr Anatskyi ◽  
Dmytro Kovalenko
Keyword(s):  
Diesel Engine ◽  
Initial Moment ◽  
Test Results ◽  
Economic Costs ◽  
Resource Saving ◽  
Start Up ◽  
Railway Industry ◽  
Wear And Tear ◽  
Cylinder Piston ◽  
Engine Components

This article discusses the measures for efficient use of fuel and energy resources in the railway industry. The calculation of the initial moment of starting the diesel engine and the necessary position of its crankshaft is made, on the basis of which it is proposed to modernize the locomotive start-up system with a decompressor. These measures are aimed at reducing the dynamic loads of engine components and reducing their wear and tear, as well as failure preventing. A method for the clean-up of fuel systems and the cylinder-piston diesel engine group of diesel locomotives was developed and tested using a special cleaning liquid that dissolves and removes solidified particles from pipelines and tanks. Measures have been proposed on the use of advanced models to test the modernized locomotives that will reduce the duration of the tests, resource and economic costs. The use of advanced testing model involves choosing the level of accuracy of the test results and, consequently, their duration and cost.  

scholarly journals Hubungan Perilaku Perdagangan Investor Dengan Volume Perdagangan Di Bursa Efek Indonesia

2009 ◽  
Vol 2 (1) ◽  
Author(s):  
Ghazali Syamni
Keyword(s):  
Trading Volume ◽  
Stock Exchange ◽  
Time Interval ◽  
Time Intervals ◽  
Using Data ◽  
Changes Over Time ◽  
Relationship Of ◽  
The Relationship ◽  
Order Pattern ◽  
Over Time

This paper examines the relationship of behavior trading investor using data detailed transaction history-corporate edition demand and order history in Indonesia Stock Exchange during period of March, April and May 2005. Peculiarly, behavior placing of investor order at trading volume. The result of this paper indicates that trading volume order pattern to have pattern U shape. The pattern happened that investors have strong desires to places order at the opening and close of compared to in trading periods. While the largest orders are of market at the opening indicates that investor is more conservatively when opening, where many orders when opening has not happened transaction to match. In placing order both of investor does similar strategy. By definition, informed investors’ orders more large than uninformed investors. If comparison of order examined hence both investors behavior relatively changes over time. But, statistically shows there is not ratio significant. This implies behavior trading of informed investors and uninformed investors stable relative over time. The result from regression analysis indicates that informed investors to correlate at trading volume in all time intervals, but not all uninformed investors correlates in every time interval. This imply investor order inform is more can explain trading volume pattern compared to uninformed investor order in Indonesia Stock Exchange. Finally, result of regression also finds that order status match has greater role determines trading volume pattern intraday especially informed buy match and informed sale match. While amend, open and withdraw unable to have role to determine intraday trading volume pattern.

Active Optimum Control of Orthotropic Plates Using Piezoelectric Stiffeners

1993 ◽  
Author(s):  
Victor Birman ◽  
Sarp Adali
Keyword(s):  
Time Interval ◽  
Short Time Interval ◽  
Bending Moments ◽  
Optimum Control ◽  
Orthotropic Plates ◽  
Time Intervals ◽  
Control Forces ◽  
Short Time ◽  
Alternating Voltage ◽  
Over Time

Abstract Active control of orthotropic plates subjected to an impulse loading is considered. The dynamic response is minimized using in-plane forces or bending moments induced by piezoelectric stiffeners bonded to the opposite surfaces of the plate and placed symmetrically with respect to the middle plane. The control forces and moments are activated by a piece-wise constant alternating voltage with varying switch-over time intervals. The magnitude of voltage is bounded while the switch-over time intervals are constantly adjusted to achieve an optimum control. Numerical examples presented in the paper demonstrate the effectiveness of the method and the possibility of reducing the vibrations to very small amplitudes within a short time interval which is in the order of a second.

The Doctrine of Manifest Danger and its Relationship to Reliability, Preventive Maintenance and Fail-Safe Design

1993 ◽  
Author(s):  
Ralph L. Barnett
Keyword(s):  
Preventive Maintenance ◽  
Design Concept ◽  
Legal Issue ◽  
Proximate Cause ◽  
Reliability Design ◽  
The Bible ◽  
Safety Technology ◽  
Fail Safe ◽  
Over Time

Abstract “Dust thou art, and unto dust shalt thou return.”1 Man has made no observations that would challenge this notion from the Bible and certainly safeguarding systems fall into lockstep. Safety technology has responded to the reality of eventual degradation using four general approaches: reliability design, preventive maintenance, fail-safe design and danger manifestation. The optimum implementation of these approaches will still not eliminate accidents; indeed, no work of manor nature is or can be danger free. Nevertheless, these sophisticated approaches are capable of producing ever-increasing levels of safety, albeit, with attendant ever-increasing cost. It is at once unfortunate and unacceptable that common law2 is not equally sophisticated in dealing with the inevitable failure of safeguarding systems over time. This paper introduces The Doctrine of Manifest Danger which is defined as a design concept using direct cues or indicator devices to communicate to the community of users that the safety of a system has been compromised before injuries occur. Furthermore, the paper addresses a related legal issue by distinguishing between proximate cause and cause of action.

In Sickness and in Health

2019 ◽  
pp. 153-172
Author(s):  
Nina Macaraig
Keyword(s):  
Wear And Tear ◽  
Work Done ◽  
Over Time

Based on the evidence of narrative sources on the disasters that struck Istanbul, building inscriptions and archival records, this chapter describes the kinds of symptoms that show how the Çemberlitaş Hamamı aged over time. It defines the various causes of damage, such as fires, earthquakes, hailstorms, and daily wear and tear. Finally, the chapter analyses the repair and renovation work done to its structure in greater detail.

Finding Minimal Infrequent Elements in Multi-Dimensional Data Defined over Partially Ordered Sets and its Applications

2010 ◽  
pp. 98-116
Author(s):  
Khaled M. Elbassioni
Keyword(s):  
Association Rules ◽  
Partially Ordered Set ◽  
Quantitative Data ◽  
Partially Ordered Sets ◽  
Threshold Value ◽  
Ordered Sets ◽  
Time Intervals ◽  
Partially Ordered ◽  
The Given ◽  
Over Time

The authors consider databases in which each attribute takes values from a partially ordered set (poset). This allows one to model a number of interesting scenarios arising in different applications, including quantitative databases, taxonomies, and databases in which each attribute is an interval representing the duration of a certain event occurring over time. A natural problem that arises in such circumstances is the following: given a database D and a threshold value t, find all collections of “generalizations” of attributes which are “supported” by less than t transactions from D. They call such collections infrequent elements. Due to monotonicity, they can reduce the output size by considering only minimal infrequent elements. We study the complexity of finding all minimal infrequent elements for some interesting classes of posets. The authors show how this problem can be applied to mining association rules in different types of databases, and to finding “sparse regions” or “holes” in quantitative data or in databases recording the time intervals during which a re-occurring event appears over time. Their main focus will be on these applications rather than on the correctness or analysis of the given algorithms.

Preventive Maintenance as a Critical Success Factor in Industry 4.0

2021 ◽  
pp. 311-331
Author(s):  
Pedro Fernandes da Anunciação ◽  
Vitor Dinis ◽  
Francisco Madeira Esteves
Keyword(s):  
Internet Of Things ◽  
Preventive Maintenance ◽  
Industry 4.0 ◽  
Economic Value ◽  
The Internet ◽  
Success Factor ◽  
Critical Success ◽  
Technological Potential ◽  
Wear And Tear ◽  
The Internet Of Things

In an economy that tends to operate in real time, where companies reduce stocks and value the customization of products and services according to the needs of their customers, information systems and technologies assume a predominant role. Equipment maintenance proves to be critical in supplying markets and meeting consumer needs. Regarding the maintenance of equipment, most managers are faced with the technical indications of suppliers, serving as a reference for the respective interventions. However, these indications often do not contemplate the contingency of certain situations, excessive hours of operation, or temperatures higher than those indicated. Preventive maintenance assumes an important role in the maintenance area by allowing interventions that are more appropriate to the wear and tear of the equipment. The technological potential associated with the internet of things or analytics allows the generation of economic value by guaranteeing the adequate conditions of the equipment and by avoiding disruptions in supply to the markets.

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