Lubricant compatibility of FKM seals in synthetic oils

2019 ◽  
Vol 72 (5) ◽  
pp. 557-565
Author(s):  
Dilek Bulut ◽  
Tatjana Krups ◽  
Gerhard Poll ◽  
Ulrich Giese
Keyword(s):  
Polyethylene Glycol ◽  
Design Methodology ◽  
Elevated Temperatures ◽  
Failure Mechanisms ◽  
Standard Test ◽  
New Method ◽  
Static Tests ◽  
Content Type ◽  
Lip Seals ◽  
First Results

Purpose Elastomer seals are used in many applications. They are exposed to lubricants and additives at elevated temperatures, as well as mechanical stresses. They can only provide good sealing function when they have resistance to those factors. There are many elastomer-lubricant compatibility tests based on DIN ISO 1817 in industry. However, they are insufficient and costly. Correlations between the tests and the applications are inadequate. The purpose of this study is investigating lubricant compatibility of fluoroelastomers (FKM) seals in polyethylene-glycol (PG)- and polyalphaolefin (PAO)- based synthetic oils and developing a methodology to predict seal service life. Design/methodology/approach A new compatibility test which is more sufficient in terms of time and cost was developed and compared with a standard test, currently used in industry. Compatibility of FKM radial lip seals with PG- and PAO-based synthetic oils with different additives was investigated chemically and dynamically. Failure mechanisms were examined. Findings The new method and the Freudenberg Flender Test FB 73 11 008 showed similar results concerning damages and similar tendencies regarding wear. The additive imidazole derivative was the most critical. Static tests give indications of possible chemically active additives, but alone they are insufficient to simulate the dynamic applications. Originality/value The paper describes a new method to investigate elastomer-lubricant compatibility and gives first results with a variety of lubricants.

Performance assessment of the complex repairable system with n-identical units under (k-out-of-n: G) scheme and copula linguistic repair approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
V. V. Singh ◽  
Abubakkar Idris Mohhammad ◽  
Kabiru Hamisu Ibrahim ◽  
Ibrahim Yusuf
Keyword(s):  
Complex System ◽  
Design Methodology ◽  
New Method ◽  
Social Implications ◽  
Repairable System ◽  
Variable Technique ◽  
Content Type ◽  
Different Types ◽  
Theoretical Assessment ◽  
Practical Implications

PurposeThis paper analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The computed results are more supportable for repairable system performability analysis.Design/methodology/approachIn this paper, the authors have analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The supplementary variable technique has employed for analyzing the performance of the system.FindingsReliability measures have been computed for different types of configuration. It generalized the results for purely series and purely parallel configurations.Research limitations/implicationsThis research may be beneficial for industrial system performances whereas a k-out-of-n-type configuration exists.Practical implicationsNot sure as it is a theoretical assessment.Social implicationsThis research may not have social implications.Originality/valueThis work is the sole work of authors that have not been communicated to any other journal before.

Wildcards – natural and artificial: the combination of a panel of experts and Fuzzy TOPSIS

foresight ◽  
2017 ◽  
Vol 19 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Mohsen Mohammadi ◽  
Mohammad Rahim Eivazi ◽  
Jafar Sajjadi
Keyword(s):  
Design Methodology ◽  
Fuzzy Topsis ◽  
New Method ◽  
Weak Signals ◽  
Content Type ◽  
Participatory Foresight ◽  
The Future ◽  
Similar Character ◽  
Topsis Model

Purpose The purpose of this paper is threefold: to classify wildcards into three particular types sharing similar characteristics; use the Fuzzy TOPSIS as a new method in foresight to turn qualitative ideas into quantitative ones; and apply a combination of Fuzzy TOPSIS and a panel of experts to prioritize weak signals. Design/methodology/approach In this paper, the authors classify wildcards into three particular types which share similar character: natural wildcards, artificial wildcards (Degree 1) and artificial wildcards (Degree 2). Wildcards point to unexpected and surprising events including important results that can form watershed in the development of a specific trend. In addition, the authors present a Fuzzy TOPSIS model which can be used in various cases to prioritize a number of weak signals and put them in order, so that the most important ones are likely to yield the wildcard in the future Findings The authors presented a classification of wildcards with the same characteristics being natural wildcards, artificial wildcards (Degree 1) and artificial wildcards (Degree 2). The authors also prioritized the weak signals to deal with the most important ones and take appropriate action in advance so as to minimize possible damages and maximize the benefits of potential wildcards in an uncertain environment. Originality/value In this paper, the authors report on the prioritizing of weak signals by applying Fuzzy TOPSIS and classify wildcards. This is significant because, by identifying the most important weak signals, appropriate actions can be taken in the future if necessary. The paper should be of interest to readers in the area of participatory foresight.

Stability check of tapered steel beams in fire

2019 ◽  
Vol 10 (4) ◽  
pp. 373-398 ◽  
Author(s):  
Carlos Couto ◽  
Élio Maia ◽  
Paulo Vila Real ◽  
Nuno Lopes
Keyword(s):  
Design Methodology ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Numerical Models ◽  
Design Methods ◽  
Steel Beams ◽  
Content Type ◽  
Design Methodologies ◽  
Accurate Design ◽  
Improved Design

Purpose The purpose of this paper is to assess whether the adaptation to fire of current proposals/design methodologies at normal temperature is capable of producing accurate predictions of resistance for the out-of-plane stability of tapered beams. Design/methodology/approach The adaptation of these methodologies to fire has been done by accounting for the reduction in steel material properties with the temperature. Results were then compared to FEM calculations by performing GMNIA analyses to determine the ultimate strength of the numerical models and to ascertain the validity and accuracy of the adapted methodologies. Findings Although all methodologies produce safe results at normal temperatures, only the general method is recommended for the safety verification at elevated temperatures, although the data points were overly conservative. This investigation demonstrates the need of proper and accurate design methods for tapered beams at elevated temperatures, which should be the subject of future developments. Research limitations/implications The research in this paper is limited to the adaptation of existing room temperature design methods to fire. Therefore, possible assumptions made during the conception of the initial formulae, which may be valid exclusively for 20ºC, may have been disregarded. Originality/value For the time being, design methodologies for the safety check of tapered beams for the case of fire are inexistent. This paper investigates the adaptation of existing room temperature design to the fire situation by providing insights on their accuracy level, as well as on how to proceed. Finally, a safe design methodology for tapered beams in case of fire is provided until improved design methods are developed.

Religion and earnings: evidence from Germany

2016 ◽  
Vol 43 (8) ◽  
pp. 841-855 ◽  
Author(s):  
Elisabeth Sinnewe ◽  
Michael Kortt ◽  
Todd Steen
Keyword(s):  
Human Capital ◽  
Design Methodology ◽  
Religious Affiliation ◽  
Wage Premium ◽  
Social Characteristics ◽  
Full Time ◽  
Men And Women ◽  
Content Type ◽  
First Results ◽  
Full Time Employment

Purpose – The purpose of this paper is to estimate the association between religious affiliation and the rate of return to human capital for German men and women. Design/methodology/approach – This paper employs data from the 1997, 2003, 2007 and 2011 waves of the German Socio-Economic Panel for German men and women in full-time employment between the age of 25 and 54. The association between religious affiliation and wages was estimated using a conventional human capital model. Findings – This paper finds that Catholic men (women) received a wage premium of 4 per cent (3 per cent) relative to their Protestant counterparts, even after controlling for an extensive range of demographic, economic and social characteristics. Originality/value – The study contributes to the literature by providing – to the best of the authors’ knowledge – the first results on the wage premium received by Catholic men and women in the German labour market.

A new method for process control based on goodness of fit tests

2015 ◽  
Vol 32 (2) ◽  
pp. 132-143
Author(s):  
Mohammad Saleh Owlia ◽  
Mohammad Saber Fallah Nezhad ◽  
Mohesn Sheikh Sajadieh
Keyword(s):  
Process Control ◽  
Design Methodology ◽  
Goodness Of Fit ◽  
New Method ◽  
Content Type ◽  
Goodness Of Fit Tests ◽  
Kolmogorov Smirnov ◽  
Shift Detection ◽  
The Subject ◽  
Smirnov Test

Purpose – The purpose of this paper is to propose a new method based on goodness of fit tests for shift detection problems. Design/methodology/approach – In this method, although the distribution of gathered data from the process is the subject of control, but any out-of-control signal could also be generalized to the overall state of the process including the parameters of the distribution. Findings – Results of simulation study denote that among goodness of fit tests, the χ2 test has a better performance than the Kolmogorov-Smirnov test in detecting shifts of process. Also comparison of proposed method with traditional methods denotes that, proposed method generally has smaller probabilities of first and second type errors. Originality/value – To the best of author’s knowledge, no attention has previously been paid to application of goodness of fit tests in process control.

To explore new avenues: experiential testimonio research

2014 ◽  
Vol 52 (4) ◽  
pp. 794-812 ◽  
Author(s):  
Marie-Noelle Albert ◽  
Marie-Michele Couture
Keyword(s):  
Qualitative Research ◽  
Research Method ◽  
Design Methodology ◽  
Scientific Research ◽  
Management Science ◽  
New Method ◽  
Qualitative Research Method ◽  
Content Type ◽  
Empirical Material

Purpose – The purpose of this paper is to propose a qualitative research method for which the empirical material is drawn from the experience of a practitioner-researcher. Design/methodology/approach – First, a review of other autobiographical methods is made to show that the proposed method offers something different. Subsequently, it briefly outlines the epistemological and theoretical anchors that guided the development of the proposed method. Then it follows the path and the peculiarities of this method. And finally a few guidelines are presented for the legitimization of the knowledge generated, illustrated by an example. Findings – The proposed method is aimed at experienced practitioners who are involved in a process of scientific research. Ideally, it is carried out with a co-searcher. Originality/value – A new method of qualitative research to explore new avenues in management science.

scholarly journals Does religious affiliation influence trust?

2019 ◽  
Vol 39 (1/2) ◽  
pp. 38-51
Author(s):  
Michael A. Kortt ◽  
Joseph Drew
Keyword(s):  
Household Income ◽  
Design Methodology ◽  
Religious Affiliation ◽  
Ordinary Least Squares ◽  
Heterogeneous Population ◽  
Contemporary Society ◽  
Content Type ◽  
Ordered Logistic Regression ◽  
First Results ◽  
The Face

PurposeThe purpose of this paper is to estimate and explore how religious affiliation may influence general and local trust in contemporary society.Design/methodology/approachThis paper employs data from the 2010 and 2014 waves of the Household, Income and Labour Dynamics in Australia survey. The association between religious affiliation and trust was estimated using an ordered logistic regression and conventional ordinary least squares model.FindingsThe paper presents evidence of a statistically significant association between religious affiliation and trust that are consistent with theory.Social implicationsThis finding is important for a heterogeneous population like Australia as it seeks to build social cohesion in the face of threats to internal and external security.Originality/valueThe study contributes to the literature by providing – to the best of the authors’ knowledge – the first results on the association between religious affiliation and trust for Australia.

Detection of small target in sea clutter via multiscale directional Lyapunov exponents

Sensor Review ◽  
2019 ◽  
Vol 39 (6) ◽  
pp. 752-762
Author(s):  
Rui Wang ◽  
Xiangyang Li ◽  
Hongguang Ma ◽  
Hui Zhang
Keyword(s):  
State Space ◽  
Lyapunov Exponents ◽  
Design Methodology ◽  
Radar Data ◽  
Nonstationary Time Series ◽  
New Method ◽  
Small Target ◽  
Sea Clutter ◽  
Eigenvalues And Eigenvectors ◽  
Content Type

Purpose This study aims to provide a new method of multiscale directional Lyapunov exponents (MSDLE) calculated based on the state space reconstruction for the nonstationary time series, which can be applied to detect the small target covered by sea clutter. Design/methodology/approach Reconstructed state space is divided into non-overlapping submatrices whose columns are equal to a predetermined scale. The authors compute eigenvalues and eigenvectors of the covariance matrix of each submatrix and extract the principal components σip and their corresponding eigenvectors. Then, the angles ψip of eigenvectors between two successive submatrices were calculated. The curves of (σip, ψip) reflect the nonlinear dynamics both in kinetic and directional and form a spectrum with multiscale. The fluctuations of (σip, ψip), which are sensitive to the differences of backscatter between sea wave and target, are taken out as the features for the target detection. Findings The proposed method can reflect the local dynamics of sea clutter and the small target within sea clutter is easily detected. The test on the ice multiparameter imaging X-ban radar data and the comparison to K distribution based method illustrate the effectiveness of the proposed method. Originality/value The detection of a small target in sea clutter is a compelling issue, as the conventional statistical models cannot well describe the sea clutter on a larger timescale, and the methods based on statistics usually require the stationary sea clutter. It has been proven that sea clutter is nonlinear, nonstationary or cyclostationary and chaotic. The new method of MSDLE proposed in the paper can effectively and efficiently detect the small target covered by sea clutter, which can be also introduced and applied to military, aerospace and maritime fields.

“I played a song with the help of a magic banana”: assessing short-term making events

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jessie Nixon ◽  
Erica Halverson ◽  
Andy Stoiber ◽  
Andy Garbacz
Keyword(s):  
Design Methodology ◽  
Learning Experiences ◽  
Assessment Method ◽  
New Method ◽  
Individual Experience ◽  
Natural Setting ◽  
Short Term ◽  
Content Type ◽  
Written Responses ◽  
Learner Responses

Purpose The purpose of this study is to understand how learners describe their experiences with short-term, introductory maker experiences and to test a method for assessing learners’ experiences authentic to short-term learning. Design/methodology/approach The authors collected written responses from participants at a two-day event, STEM Center Learning Days. Through an analysis of 707 unique instances of learner responses to participation in drop-in maker activities, they examined how participants describe their short-term learning experiences. Findings The authors found that although some activities appear to onlookers to create passive experiences for learners, these seemingly passive moments have a significant impact on learners. In addition, some learners described themselves as working in tandem with tools to make something work and other learners viewed the tools as working autonomously. They found that the assessment method allowed them to gain an understanding of how learners describe their experiences offering important implications for understanding short-term learning events. Originality/value The findings provide researchers studying short-term learning in its natural setting a new method to understand how learners make sense of their individual experience. Further, designers of short-term learning experiences may gain insights into their unique activities and indications of where additional guidance and scaffolds will improve small learning moments.

Automatic disassembly navigation for accurate virtual assembly path planning

2014 ◽  
Vol 34 (3) ◽  
pp. 244-254 ◽  
Author(s):  
Wanbin Pan ◽  
Yigang Wang ◽  
Peng Du
Keyword(s):  
Virtual Reality ◽  
Path Planning ◽  
Virtual Environment ◽  
Design Methodology ◽  
Virtual Assembly ◽  
New Method ◽  
Virtual Reality System ◽  
New Approach ◽  
Content Type ◽  
Human Interactions

Purpose – The purpose of this paper is to develop an automatic disassembly navigation approach for human interactions in the virtual environment to achieve accurate and effective virtual assembly path planning (VAPP). Design/methodology/approach – First, to avoid the error-prone human interactions, a constraint-based disassembly method is presented. Second, to automatically provide the next operable part(s), a disassembly navigation mechanism is adopted. Finally, the accurate assembly path planning can be obtained effectively and automatically by inversing the ordered accurate disassembly paths, which are obtained interactively in the virtual environment aided with the disassembly navigation matrix. Findings – The applications present that our approach can effectively avoid the error-prone interactive results and generate accurate and effective VAPP. Research limitations/implications – There are several works that could be conducted to make our approach more general in the future: to further study the basic disassembly direction deducing rules to make the process of determining disassembly direction totally automatic, to consider the hierarchy of the parts in virtual reality system and to consider the space for assembly/disassembly tools or operators. Originality/value – The approach has the following characteristics: a new approach to avoid the error-prone human interactions for accurate assembly path planning obtaining, a new constraint deducing method for determining the disassembly semantics automatically or semi-automatically is put forward and a new method for automatically identifying operable parts in VAPP is set forward.

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