Methodology for wear mapping error quantification

2020 ◽  
Vol 72 (9) ◽  
pp. 1043-1050 ◽  
Author(s):  
Tiago Cousseau ◽  
Adriano Gonçalves Passos
Keyword(s):  
Image Analysis ◽  
Peer Review ◽  
Optical Interferometry ◽  
Lower Threshold ◽  
Wear Volume ◽  
Content Type ◽  
Practical Applications ◽  
Numerical Errors ◽  
Wear Map ◽  
The Difference

Purpose The purpose of this paper is to propose a methodology to quantify the error on wear volume evaluation using optical interferometry with image analysis (OI+IA), to establish a lower threshold for wear mapping in practical applications. Design/methodology/approach A three-dimensional surface wear map is quantified by measuring the same area of a surface before and after a wear process using optical interferometry. Then, by subtracting the matching images, the wear map (volume of wear) is obtained. To access the error related to wear mapping, the difference between several consecutive measurements of the same unworn surface was performed and deeply investigated. Findings The paper shows that the difference between two consecutive measurements of the same unworn surface, which ideally should be zero, is not. Thus, the magnitude of this “wear map” is the error. The main causes of such uncertainties are because of sample motion in a subpixel scale; a combination between surface roughness with the selected resolution; and numerical errors on the relocation process that is used to match the surfaces before subtracting them. Practical implications The proposed methodology allows one to define the lower threshold for wear map analysis using OI+IA. To know the limitation of OI+IA for wear mapping prevents misevaluation of the so-called almost-zero-wear. Originality/value This paper covers and identifies main uncertainties and numerical errors related to optical interferometry assisted by image analysis for wear mapping. Several other papers deal with uncertainties of OI; however, this paper proposes a simple methodology to evaluate the lower threshold for wear mapping. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0354

Synergistic effects of antiwear and friction modifier additives

2020 ◽  
Vol 72 (8) ◽  
pp. 1019-1025
Author(s):  
Jennifer Eickworth ◽  
Enes Aydin ◽  
Martin Dienwiebel ◽  
Thomas Rühle ◽  
Patrick Wilke ◽  
...  
Keyword(s):  
Peer Review ◽  
Photoelectron Spectroscopy ◽  
Synergistic Effects ◽  
Film Formation ◽  
Wear Volume ◽  
Friction Modifier ◽  
Quartz Crystals ◽  
Content Type ◽  
Representative Study ◽  
Wear Reduction

Purpose Interactions of different additive types for antiwear/friction modification on surfaces can be synergistic or antagonistic in nature. This paper aims to investigate whether there are interactions between different additives in the adsorption process and whether they synergistic or antagonistic. The yielded correlations will be validated with tribological experiments to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction. Design/methodology/approach In a representative study, zinc dialkyl-dithiophosphate and dithiophosphate were elaborated in combination with two different friction modifiers, a glycerol monooleate and an organic friction modifier. As base oils, mineral oil and poly alpha olefine were used. The adsorption behavior was studied via quartz crystal microbalance with dissipation using Fe2O3 coated quartz crystals. The tribological performance was evaluated in a ball-on-three disk tribometer. White light interferometry was used to determine the wear volume and X-ray photoelectron spectroscopy depth profiles of the tribofilms were obtained on selected systems. Findings The combination of dithiophosphate and an organic friction modifier (OFM) revealed a synergistic effect in terms of wear. If the initially formed films are viscoelastic, the third body formation during a tribo experiment is more pronounced and thereby wear can be reduced. As a mechanism, the adsorption of the OFM on the formed antiwear layer is proposed. Originality/value Correlating the analytical findings with performance experiments provides further understanding of the interactions between different constituents and their implications on film formation processes and wear reduction mechanisms. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0293/

An investigation of impact-sliding behavior and fretting wear of tubes against different supports in steam generators

2020 ◽  
Vol 72 (10) ◽  
pp. 1295-1301
Author(s):  
Kai Guo ◽  
Zhongli Han ◽  
Yipeng Wang ◽  
Yang Wang ◽  
Wei Tan
Keyword(s):  
Peer Review ◽  
Wear Behavior ◽  
Fretting Wear ◽  
Impact Factors ◽  
Wear Volume ◽  
Steam Generators ◽  
Content Type ◽  
Circular Holes ◽  
Wear Calculation ◽  
Interaction Characteristic

Purpose The purpose of this study is to reveal the interaction behavior between tubes and supports in steam generators and study the fretting wear of tubes in different load conditions. Design/methodology/approach The fretting wear tests were conducted to investigate the fretting wear behavior of the tubes against three kinds of supports: the drilled circular holes (DCH), anti-vibration bars (AVBs) and trefoil orifice holes (TOH), which are widely used supports in nuclear steam generators. In this paper, the comparison of the interaction characteristic with different impact factors was established such as clearances and loads in the three kinds of supports. The fretting wear volume and scars were analyzed by a scanning electron microscope and 3D profiler. Findings The results show that impact can play a more important role in the DCH and TOH supports than that in AVBs. The normal work rate can be underestimated in the DCH and TOH supports. Originality/value The results of this study can be reference of fretting wear calculation in the design of steam generators with different kinds of supports and can be guidance in the maintenance of steam generators. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0513/

A compounding-model comprising back propagation neural network and genetic algorithm for performance prediction of bio-based lubricant blending with functional additives

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tong Yu ◽  
Peng Yin ◽  
Wei Zhang ◽  
Yanliang Song ◽  
Xu Zhang
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Peer Review ◽  
High Efficiency ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Wear Volume ◽  
Combined Model ◽  
Data Set ◽  
Content Type

Purpose The amount, type and addition conditions of additives of lubricants should be continuously adjusted to obtain appealing performance. To obtain the optimal pretreatment parameters and reduce the cost of time-consuming experiments, the purpose of this paper is to establish an optimal back propagation neural network (BPNN) model combined with genetic algorithm (GA) in this work. Design/methodology/approach Using trimethylolpropane trioleate as the base oil and three types of phosphorus compounds as additives, 25 sets of lubricant formulas were designed regarding lubricant performances of average friction coefficient, average spot diameter, disk wear volume and extreme pressure. The data set was used for training and learning of BPNN and then combined with GA to optimize BPNN with continuously optimization by adjusting various parameters. Findings Comparing prediction data of BPNN with actual test data, correlation coefficients were above 90%, indicating that the model could accurately predict the performance of lubricants. When combined with GA, all performance errors were less than 5%, indicating that BPNN could be optimized by GA to obtain an accurate combined model for prediction of lubricant performance. The best additive formula with excellent performances was obtained from the BPNN–GA model. Originality/value This work developed a new method to study lubricant compounding. The combined model was expected to provide a theoretical basis and guidance for the compounding optimization of lubricant additives with high efficiency and low cost and to expand the scope to practical applications. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0165/

Effect of load on the fretting behavior of SAF 2507 super duplex stainless steel in air and sea water

2019 ◽  
Vol 72 (5) ◽  
pp. 651-656
Author(s):  
Mengjiao Wang ◽  
Yunxia Wang ◽  
Hao Liu ◽  
Fengyuan Yan
Keyword(s):  
Friction Coefficient ◽  
Peer Review ◽  
Applied Load ◽  
Sea Water ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Volume ◽  
Wear Loss ◽  
Content Type ◽  
Slip Regime

Purpose This paper aims to study the influence of load and environment medium on the fretting behavior of SAF 2507 SDSS. Design/methodology/approach In this study, the effect of load on the fretting behavior of SAF 2507 SDSS in air and sea water were studied. The fretting wear tests under different loads were conducted with a ball-on-flat contact configuration. The friction coefficient, wear volume, surface morphology and oxidation component were determined. Findings With the increase of applied load, the friction coefficient decreases both in air and sea water. The fretting mechanism is gradually transformed from partial slip regime to slip regime in air while the fretting counterparts are all in the state of gross slip in sea water. In sea water, the friction coefficient is lower while the wear loss is higher compared with that in air. Research limitations/implications This research suggests that the fretting behavior of SAF 2507 SDSS is related to load and environment medium. Practical implications The results may help us to choose the appropriate load under different environments. Originality/value The main originality of the research is to reveal the fretting behavior of SAF 2507 SDSS under different loads in air and sea water, which would help us to realize fretting behavior of SAF 2507 SDSS is controlled by the combination of applied load and lubricating environment. Peer review The peer review history for this article is available at: http://dx.doi.org/10.1108/ILT-08-2019-0335.

Study on high-temperature wear and mechanism of Al-Si/graphite composites prepared by the die-casting process

2020 ◽  
Vol 72 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yafei Deng ◽  
Xiaotao Pan ◽  
Guoxun Zeng ◽  
Jie Liu ◽  
Sinong Xiao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Peer Review ◽  
Die Casting ◽  
Casting Machine ◽  
Injection Pressure ◽  
Casting Process ◽  
Matrix Alloy ◽  
Content Type ◽  
The Matrix

Purpose This paper aims to improve the tribological properties of aluminum alloys and reduce their wear rate. Design/methodology/approach Carbon is placed in the model at room temperature, pour 680°C of molten aluminum into the pressure chamber, and then pressed it into the mold containing carbon felt through a die casting machine, and waited for it to cool, which used an injection pressure of 52.8 MPa and held the same pressure for 15 s. Findings The result indicated that the mechanical properties of matrix and composite are similar, and the compressive strength of the composite is only 95% of the matrix alloy. However, the composite showed a low friction coefficient, the friction coefficient of Gr/Al composite is only 0.15, which just is two-third than that of the matrix alloy. Similarly, the wear rate of the composite is less than 4% of the matrix. In addition, the composite can avoid severe wear before 200°C, but the matrix alloy only 100°C. Originality/value This material has excellent friction properties and is able to maintain this excellent performance at high temperatures. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0454/

What makes the difference? Employee social media brand engagement

2019 ◽  
Vol 34 (7) ◽  
pp. 1459-1467 ◽  
Author(s):  
Sherese Y. Duncan ◽  
Raeesah Chohan ◽  
João José Ferreira
Keyword(s):  
Social Media ◽  
Brand Equity ◽  
Positive Emotions ◽  
Content Type ◽  
Word Use ◽  
Brand Engagement ◽  
Analytical Thinking ◽  
Industry Competition ◽  
The Difference ◽  
Business To Business

Purpose This paper aims to explore, using the employee lens of business-to-business firms, word use through brand engagement and social media interaction to understand the difference between employees who rate their employer brands highly on social media and those who don't. Design/methodology/approach We conducted a textual content analysis of posts published on the social media job evaluation site glassdoor.com. LIWC software package was used to analyze 30 of the top 200 business-to-business brands listed on Brandwatch using four variables, namely, analytical thinking, clout, authenticity and emotional tone. Findings The results show that employees who rate their employer’s brand low use significantly more words, are significantly less analytic and write with significantly more clout because they focus more on others than themselves. Employees who rate their employer’s brand highly, write with significantly more authenticity, exhibit a significantly higher tone and display far more positive emotions in their reviews. Practical implications Brand managers should treat social media data disseminated by individual stakeholders, like the variables used in this study (tone, word count, frequency), as a valuable tool for brand insight on their industry, competition and their own brand equity, now and especially over time. Originality/value This study provides acknowledgement that social media is a significant source of marketing intelligence that may improve brand equity by better understanding and managing brand engagement.

Socioeconomic effects of pension spending: evidence from Spain

2020 ◽  
Vol 47 (5) ◽  
pp. 599-617
Author(s):  
Fernando Bermejo ◽  
Eladio Febrero ◽  
Andre Fernandes Tomon Avelino
Keyword(s):  
Peer Review ◽  
Social Protection ◽  
Pension System ◽  
Decomposition Analysis ◽  
Value Added ◽  
Total Output ◽  
Alternative View ◽  
Input Output ◽  
Structural Decomposition Analysis ◽  
Content Type

PurposeThe purpose of this study is to provide broader understanding of the significant role that the pension system has in the Spanish economy by estimating the sectoral production, employment and income sustained by pensioners' consumption.Design/methodology/approachBased on input–output tables by the World Input–Output Database and consumption data from the Household Budget Survey by the Spanish Statistical Office, a demoeconomic model is applied to quantify the direct impacts, indirect impacts from interindustry links and induced impacts from income–consumption connections over a nine-year period (2006–2014). Then, the factors driving the evolution of total output, employment and value added during such period have been examined by using structural decomposition analysis.FindingsThe growing participation of consumption by pensioner households in final demand had proven crucial during the 2008 crisis to alleviate the negative trend in production and employment derived from the collapse in consumption suffered by the rest of households.Practical implicationsDetermining the underlying factors driving changes in both employment and income during the 2008 crisis can be of interest in political decision-making on the sustainability of the Spanish pension system.Social implicationsThe results of estimating both the employment and income supported by pensioners' consumption reveal the significant stabilizing effect of the public spending on pensions, particularly during the 2008 crisis.Originality/valueThe current Spanish approach of attaining the pension system sustainability by merely reducing social protection costs ignores the adverse consequences of a lower pensioners' demand. This paper addresses an alternative view in which pension spending is not considered a burden on economic growth but rather a means of improving the level of production and employment.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-01-2019-0047

scholarly journals A Dynamic Distance Measure of Picture Fuzzy Sets and Its Application

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 436
Author(s):  
Ruirui Zhao ◽  
Minxia Luo ◽  
Shenggang Li
Keyword(s):  
Fuzzy Sets ◽  
Distance Measure ◽  
Distance Measures ◽  
Numerical Comparison ◽  
Mathematical Tool ◽  
Practical Applications ◽  
Fuzzy Point ◽  
Point Operator ◽  
The Difference ◽  
Picture Fuzzy Sets

Picture fuzzy sets, which are the extension of intuitionistic fuzzy sets, can deal with inconsistent information better in practical applications. A distance measure is an important mathematical tool to calculate the difference degree between picture fuzzy sets. Although some distance measures of picture fuzzy sets have been constructed, there are some unreasonable and counterintuitive cases. The main reason is that the existing distance measures do not or seldom consider the refusal degree of picture fuzzy sets. In order to solve these unreasonable and counterintuitive cases, in this paper, we propose a dynamic distance measure of picture fuzzy sets based on a picture fuzzy point operator. Through a numerical comparison and multi-criteria decision-making problems, we show that the proposed distance measure is reasonable and effective.

scholarly journals SME credit constraints and access to informal credit markets in Vietnam

2020 ◽  
Vol 47 (6) ◽  
pp. 787-807 ◽  
Author(s):  
Lan Archer ◽  
Parmendra Sharma ◽  
Jen-Je Su
Keyword(s):  
Peer Review ◽  
Credit Markets ◽  
Credit Constraints ◽  
Policy Implications ◽  
Informal Credit ◽  
Banking Services ◽  
Content Type ◽  
Credit Access ◽  
Access Policy ◽  
Correlated Random Effects

PurposeA review of literature has documented that accessing formal credit and other banking services has always been a crucial challenge for small and medium-sized enterprises (SMEs). The alternative, therefore, tends to be informal channels. However, the credit constraint vis-à-vis informal channel link does not appear to be well documented in the literature. This study aims to investigate whether credit constraints significantly affect the probability of accessing informal credit, as well as the credit values of Vietnamese SMEs.Design/methodology/approachThis study uses a trinary approach and correlated random-effects Probit and Tobit techniques to avoid the incidental coefficients problem.FindingsThe results suggest that relative to unconstrained and partially constrained firms, fully constrained firms tend to be more active in the informal credit markets, shown by their higher probability of informal credit access and larger credit values.Originality/valueTo the best of authors’ knowledge, this is the first study on Vietnam that takes a different approach to credit constraints and examines their impact on informal credit access. Policy implications arise and are discussed.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-11-2017-0543

Zn diffusion and reflow behaviour of Sn-9Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga solders on a Ni/Cu substrate under IR reflow

2014 ◽  
Vol 26 (2) ◽  
pp. 87-95 ◽  
Author(s):  
J. Mittal ◽  
K.L. Lin
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Content Type ◽  
Diffusion Behavior ◽  
Zn Diffusion ◽  
Cu Substrate ◽  
Practical Applications ◽  
Substrate Interface ◽  
Solder Balls ◽  
Practical Implications

Purpose – This paper aims to compare the reflow and Zn diffusion behaviors in Sn-Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga (5E) solders during soldering on a Ni/Cu substrate under infrared (IR) reflow. The study proposes a model on the effect of various elements particularly Zn diffusion behavior in the solders on the formation of intermetallic compounds (IMCs). Design/methodology/approach – The melting activities of two solders near their melting points on copper substrates are visualized in an IR reflow furnace. Reflowed solder joints were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. Findings – Reflow behaviors of the solders are similar. During melting, solder balls are first merged into each other and then reflow on the substrate from top to bottom. Both solders show a reduced amount of Zn in the solder. Theoretical calculations demonstrate a higher Zn diffusion in the 5E solder; however, the amount of Zn actually observed at the solder/substrate interface is lower than Sn-9Zn solder due to the formation of ZnAg3 in the solder. A thinner IMC layer is formed at the interface in the 5E solder than the Sn-Zn solder. Research limitations/implications – The present work compares the 5E solder only with Sn-Zn solder. Additional research work may be required to compare 5E solder with other solders like Sn-Ag, SnAgCu, etc. to further establish its practical applications. Practical implications – The study ascertains the advantages of 5E solder over Sn-Zn solder for all practical applications. Originality/value – The significance of this paper is the understanding of the relation between reflow behavior of solders and reactivity of different elements in the solder alloys and substrate to form various IMCs and their influence on the formation of IMC layer at solder/substrate interface. Emphasis is provided for the diffusion behavior of Zn during reflow and respective reaction mechanisms.

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