Test and evaluation method for greases in grease-sealing rotary shaft seals

2021 ◽  
Vol 68 (5) ◽  
pp. 24-31
Author(s):  
Susanne Hahn ◽  
Simon Feldmeth
Keyword(s):  
Evaluation Method ◽  
Friction Torque ◽  
Rapid Testing ◽  
Test Rig ◽  
The Past ◽  
Test And Evaluation ◽  
System A ◽  
System Components ◽  
Starved Lubrication ◽  
Shaft Seals

Grease-lubricated sealing systems show starved lubrication much more frequently than oil lubricated sealing systems. Different greases provide different lubricity to the sealing system. A test and evaluation method was developed that allows to assess the lubricity of different greases and to compare them with each other. The test and evaluation method consists of a test run and a subsequent analysis of the test components. The test run comprises a 24-hour speed collective and is performed on a test rig using real sealing system components. For the evaluation method, eight criteria are analysed, which are rated suitable for evaluating starved lubrication. The criteria include parameters measured during the test run, such as friction torque and temperature, as well as parameters inspected in the subsequent examination of all test components. All criteria are assessed and combined to an overall score, that allows to directly compare different greases with each other. The test and evaluation method developed reveals significant differences between 23 greases examined. Thus, the lubricity of greases in sealing systems can be analysed and compared much more quickly than in the past. Thanks to the rapid testing and focused evaluation of the relevant criteria, greases can be tested much more cost- and resource-efficiently than before.

Research on Modeling and Analysis of Testability for Complex Electronic System

2014 ◽  
Vol 701-702 ◽  
pp. 236-240
Author(s):  
Xiu Fang Wang ◽  
Bin Chen ◽  
Jin Ye Peng ◽  
Wei Qi
Keyword(s):  
Confidence Level ◽  
Binomial Distribution ◽  
Statistical Models ◽  
Evaluation Method ◽  
Electronic System ◽  
Modeling And Analysis ◽  
Index Model ◽  
Test And Evaluation ◽  
System A ◽  
The Relationship

Due to the lack of effective modeling and analysis methods for testability of complex electronic system, a testability index model is established to resolve this problem. First of all, the existing testability demonstration test and evaluation method are analyzed. On this basis, testability indexes statistical models based on the binomial distribution, or Beta distribution and F distribution are established. What’s more, the relationship and principle between the fault detection or isolation data and the confidence level are analyzed in these models. Finally, the result of simulation shows that these models are practical and effective, which provides a new way of effectively analyzing and evaluating testability indexes of complex electronic system.

The Rapid Iterative Test and Evaluation Method (RITE)

2018 ◽  
Author(s):  
Michael C. Medlock
Keyword(s):  
Evaluation Method ◽  
Test And Evaluation ◽  
Original Case ◽  
Definition Of

This chapter begins with a discussion of the philosophy and then definition of the RITE method. It then delves into the benefits of this method and provides practical notes on running RITE tests effectively. The chapter concludes with an overview of the original case study behind the 2002 article documenting this method.

Voltage Sag Evaluation Method of a Real Distribution System Based on a Connection Number Model

2013 ◽  
Vol 341-342 ◽  
pp. 1363-1366
Author(s):  
Lang Bai ◽  
Le Yu
Keyword(s):  
Distribution System ◽  
Evaluation Method ◽  
Assessment Model ◽  
Voltage Sag ◽  
Voltage Sags ◽  
Connection Number ◽  
Reliability Parameters ◽  
Real Distribution ◽  
System Components ◽  
Simulation Results

The evaluation results of power system are greatly influenced by the reliability parameters and uncertainty of system components. The connection number assessment model and an approach have been presented to assess the occurrence frequency due to voltage sags. The proposed method had been applied to a real distribution system. Compared with the interval number method, the simulation results have shown that this method is simple and flexible.

scholarly journals The Museum System of Modern Kazakhstan: Classification and Typology of Museums

2021 ◽  
Vol 9 (2) ◽  
pp. 79-89
Author(s):  
Abay Satubaldin ◽  
Kunikey Sakhiyeva
Keyword(s):  
National Level ◽  
Regional Level ◽  
District Level ◽  
Soviet System ◽  
Provincial Level ◽  
The Past ◽  
System A ◽  
The Subject ◽  
First Time

This article discusses the museum system of modern Kazakhstan and offers, for the first time ever, a classification and typology of the country’s museums.In recent years in independent Kazakhstan, on the basis of the Soviet system, a modern museum network has been formed which currently lists 250 museums. Among them are 17 national-level museums, 54 at the regional level, 73 at the provincial level, 103 branches of regional- and district-level museums and four private museums.The purpose of this article is to analyse the museum system of modern Kazakhstan and develop a classification and typology of the country’s museums.In the course of the study, conducted in 2017–2018, data was collected on the activities of museums at the national, regional and district levels over the past seven years. From the results of this investigation, the museums of Kazakhstan were systematized according to the subject or topic of the museum (e.g. history, art, scientific), its affiliation (national, regional district), and by size, measured by number of employees.

Comparison of Different Methods for the Evaluation of Cavitation Damaged Surfaces

2005 ◽  
Author(s):  
B. Bachert ◽  
G. Ludwig ◽  
B. Stoffel ◽  
S. Baumgarten
Keyword(s):  
Mass Loss ◽  
White Light ◽  
Cavitation Erosion ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Special Device ◽  
Test Rig ◽  
Rotating Disc ◽  
White Light Interferometer ◽  
Initial Stage

The experimental data which will be presented in this paper are the results of the comparison between different methods for evaluating damaged surfaces by cavitation erosion. The different methods are partly working in the initial stage of cavitation erosion and partly at developed cavitation erosion, where mass loss occurs. The used test rig consists basically of a rotating disc with a diameter of 500 mm on which four holes are located. Each hole generates a cavitation zone while the disc is rotating. The test objects are material specimens made of copper. Copper was used as test material in respect to reasonable durations for the tests. The specimen can be implemented in the casing of the test rig directly across the rotating disc on the diameter where the holes are located. This rotating disc test rig generates a very aggressive type of cavitation, so that mass loss, of course depending on the tested material, will appear after relatively short durations. Also the initial stage of cavitation erosion can be observed. The used test rig is very interesting regarding the possibility to apply different measuring techniques to characterize the erosive aggressiveness of cavitation. These techniques are at first the so-called Pitcount-Method, which allows investigations of cavitation erosion in the initial stage. The second one is an acoustic method, which is based on a structure-borne noise sensor and a specially developed signal processing system. The third method is the measuring of mass loss of the material specimen after several time steps. With the help of a CCD-camera and special digital image processing software, images of different cavitation conditions were recorded. The information obtained from these images should serve as support for the evaluation of the other used methods. After the evaluation with the above mentioned methods, the specimens were evaluated with a special device which works with the help of a white light interferometer. With this evaluation method three-dimensional information can be obtained in respect to the actually eroded volume of the specimens. With this information the lost mass of the specimens could be calculated directly. Especially the comparison of the results obtained from the Pitcount-Method, which is a two-dimensional evaluation method, and the three-dimensional results of the white light interferometer is an important point of the work within this paper.

Climatic and tectonic controls on strath terraces along the upper Weihe River in central China

2016 ◽  
Vol 86 (3) ◽  
pp. 326-334 ◽  
Author(s):  
Hongshan Gao ◽  
Zongmeng Li ◽  
Yapeng Ji ◽  
Baotian Pan ◽  
Xiaofeng Liu
Keyword(s):  
Yellow River ◽  
Central China ◽  
Fluvial Deposits ◽  
The Past ◽  
River Incision ◽  
System A ◽  
Fluvial Incision ◽  
Quaternary Climate ◽  
Field Investigations ◽  
Weihe River

AbstractThe Weihe River in central China is the largest tributary of the Yellow River and contains a well-developed strath terrace system. A new chronology for the past 1.11 Ma for a spectacular flight of strath terraces along the upper Weihe River near Longxi is defined based on field investigations of loess—paleosol sequences and magnetostratigraphy. All the strath terraces are strikingly similar, having several meters of paleosols that have developed directly on top of fluvial deposits located on the terrace treads. This suggests that the abandonment of each strath terrace by river incision occurred during the transition from glacial to interglacial climates. The average fluvial incision rates during 1.11—0.71 Ma and since 0.13 Ma are 0.35 and 0.32 m/ka, respectively. These incision rates are considerably higher than the average incision rate of 0.16 m/km for the intervening period between 0.71 and 0.13 Ma. Over all our results suggest that cyclic Quaternary climate change has been the main driving factor for strath terrace formation with enhanced episodic uplift.

Research on sealing performance of oil seals with micro-dimple texture on lips

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fuying Zhang ◽  
Yuanhao Zhang
Keyword(s):  
Peer Review ◽  
Surface Texture ◽  
Elastohydrodynamic Lubrication ◽  
Friction Torque ◽  
Pumping Rate ◽  
Content Type ◽  
Rotation Direction ◽  
Sealing Performance ◽  
Pumping Efficiency ◽  
Shaft Seals

Purpose The purpose of this paper is to study the pumping efficiency of oil seals with different surface textures at different speeds, and the influence of the rotation direction of triangular texture on the sealing performance was further analyzed. Design/methodology/approach Based on the theory of elastohydrodynamic lubrication and the pumping mechanism of rotary shaft seals, establishing a numerical model of mixed lubrication in oil seal sealing area. The model is coupled with the lip surface texture parameters and the two-dimensional average Reynolds equation considering the surface roughness. Findings The results show that the application of lip surface texture technology has obvious influence on the oil film thickness, friction torque and pumping rate of oil seal. The triangular texture has the most significant effect on the increase of pump suction rate. When the rotation direction of triangular texture is 315 degrees, the pumping rate of oil seal is the largest compared with the other seven directions. Originality/value The model has a comprehensive theoretical guidance for the design of new oil seal products, which provides a certain basis for the application of surface texture technology in the field of sealing in the future. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0198/

Evaluating Augmented and Virtual Reality in Education Through a User-Centered Comparative Study

2020 ◽  
pp. 229-261 ◽  
Author(s):  
Roberto Pierdicca ◽  
Emanuele Frontoni ◽  
Maria Paola Puggioni ◽  
Eva Savina Malinverni ◽  
Marina Paolanti
Keyword(s):  
Virtual Reality ◽  
Comparative Study ◽  
Cultural Heritage ◽  
Evaluation Method ◽  
Smart Devices ◽  
Learning Approaches ◽  
Computational Power ◽  
Real Effect ◽  
The Past ◽  
Education Process

Augmented and virtual reality proved to be valuable solutions to convey contents in a more appealing and interactive way. Given the improvement of mobile and smart devices in terms of both usability and computational power, contents can be easily conveyed with a realism level never reached in the past. Despite the tremendous number of researches related with the presentation of new fascinating applications of ancient goods and artifacts augmentation, few papers are focusing on the real effect these tools have on learning. Within the framework of SmartMarca project, this chapter focuses on assessing the potential of AR/VR applications specifically designed for cultural heritage. Tests have been conducted on classrooms of teenagers to whom different learning approaches served as an evaluation method about the effectiveness of using these technologies for the education process. The chapter argues on the necessity of developing new tools to enable users to become producers of contents of AR/VR experiences.

Evaluation of ontology structural metrics based on public repository data

2019 ◽  
Vol 21 (2) ◽  
pp. 473-485
Author(s):  
Manuel Franco ◽  
Juana María Vivo ◽  
Manuel Quesada-Martínez ◽  
Astrid Duque-Ramos ◽  
Jesualdo Tomás Fernández-Breis
Keyword(s):  
Evaluation Method ◽  
Measurement Instrument ◽  
Public Repository ◽  
Standard Methods ◽  
The Past ◽  
Biological Ontologies ◽  
Quality Aspects ◽  
Ontology Metrics ◽  
The Stability ◽  
Structural Metrics

Abstract The development and application of biological ontologies have increased significantly in recent years. These ontologies can be retrieved from different repositories, which do not provide much information about quality aspects of the ontologies. In the past years, some ontology structural metrics have been proposed, but their validity as measurement instrument has not been sufficiently studied to date. In this work, we evaluate a set of reproducible and objective ontology structural metrics. Given the lack of standard methods for this purpose, we have applied an evaluation method based on the stability and goodness of the classifications of ontologies produced by each metric on an ontology corpus. The evaluation has been done using ontology repositories as corpora. More concretely, we have used 119 ontologies from the OBO Foundry repository and 78 ontologies from AgroPortal. First, we study the correlations between the metrics. Second, we study whether the clusters for a given metric are stable and have a good structure. The results show that the existing correlations are not biasing the evaluation, there are no metrics generating unstable clusterings and all the metrics evaluated provide at least reasonable clustering structure. Furthermore, our work permits to review and suggest the most reliable ontology structural metrics in terms of stability and goodness of their classifications. Availability: http://sele.inf.um.es/ontology-metrics

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