scholarly journals Factors influencing bearing vibration level

2018 ◽  
Vol 19 (12) ◽  
pp. 273-276 ◽  
Author(s):  
Bartłomiej Ambrożkiewicz ◽  
Krzysztof Przystupa ◽  
Sylwester Wnuk
Keyword(s):  
Vibration Level ◽  
Research Experience ◽  
Durability Test ◽  
Technical Literature ◽  
Factors Affecting ◽  
Term Operation ◽  
Factors Influencing ◽  
Shape Errors ◽  
Bearing Vibration

This article presents the problem of factors influencing bearing vibration level, which is a comprehensive parameter providing information about bearing condition. Basing on technical literature and research experience, factors affecting bearing vibration level will be defined, both originating from shape errors, as well as those that may have occurred during long-term operation. Additionally, the methodology is described in accordance with ISO-15242 standard, concerning bearing vibration level tests performance. Experiment considered bearing vibration level measurements for bearing 6208C3, for post-production parts and those that have passed durability test. Comparative analysis included a compilation of numerical values and finding a correlation between level of bearing wear and mentioned parameter.

scholarly journals Review of the Durability of Polymer Electrolyte Membrane Fuel Cell in Long-Term Operation: Main Influencing Parameters and Testing Protocols

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4048
Author(s):  
Huu Linh Nguyen ◽  
Jeasu Han ◽  
Xuan Linh Nguyen ◽  
Sangseok Yu ◽  
Young-Mo Goo ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Failure Modes ◽  
Polymer Electrolyte Membrane ◽  
Durability Test ◽  
Term Operation ◽  
Electrolyte Membrane ◽  
Transportation Applications ◽  
Testing Protocols

Durability is the most pressing issue preventing the efficient commercialization of polymer electrolyte membrane fuel cell (PEMFC) stationary and transportation applications. A big barrier to overcoming the durability limitations is gaining a better understanding of failure modes for user profiles. In addition, durability test protocols for determining the lifetime of PEMFCs are important factors in the development of the technology. These methods are designed to gather enough data about the cell/stack to understand its efficiency and durability without causing it to fail. They also provide some indication of the cell/stack’s age in terms of changes in performance over time. Based on a study of the literature, the fundamental factors influencing PEMFC long-term durability and the durability test protocols for both PEMFC stationary and transportation applications were discussed and outlined in depth in this review. This brief analysis should provide engineers and researchers with a fast overview as well as a useful toolbox for investigating PEMFC durability issues.

scholarly journals Factors Influencing Exhibitor Satisfaction and Loyalty: A Meta-Analysis on the Chinese Exhibition Market

2020 ◽  
Vol 12 (20) ◽  
pp. 8390 ◽  
Author(s):  
Linyan Liu ◽  
Zheng Xiang ◽  
Yuyao Liu ◽  
Florian J. Zach ◽  
Nancy McGehee
Keyword(s):  
Literature Review ◽  
Meta Analysis ◽  
Tourism Industry ◽  
The Internet ◽  
Management Service ◽  
Factors Affecting ◽  
Factors Influencing ◽  
Comprehensive Literature Review ◽  
Hospitality And Tourism Industry

With the exhibition sector becoming increasingly important for the hospitality and tourism industry, it is critical to understand what drives the success of an exhibition. Through a comprehensive literature review, we first identified two broad categories of factors, namely exhibition attributes and exhibitor perceptions, that influence exhibitor satisfaction and loyalty. Next, a meta-analysis was conducted based on 26 empirical papers studying the Chinese exhibition market to quantitatively evaluate these relationships. The results show that among the exhibition attributes, booth management, service personnel, and exhibition environment are the most important factors affecting exhibitor satisfaction, while exhibition brand is the most important factor affecting loyalty. Among exhibitor perceptions, service quality is more important for satisfaction, while perceived value is more meaningful to loyalty. This study offers insights into strategies for exhibition organizers to cultivate long-term relationships, and to better cope with the challenges of emerging forces such as the Internet.

Field Study on Pump Vibration and ISO’s New Criteria

1999 ◽  
Vol 121 (4) ◽  
pp. 798-803 ◽  
Author(s):  
Toshiyuki Osada ◽  
Takashi Kawakami ◽  
Tadashi Yokoi ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Rotational Speed ◽  
Work Group ◽  
Field Measurements ◽  
Rotating Machinery ◽  
International Organization ◽  
Vibration Level ◽  
Term Operation ◽  
New Criteria

ISO 10816-3 (a new standard of International Organization for Standardization) was established as vibration criteria for industrial rotating machinery based on the bearing housing vibration in situ. The appropriateness of the application of the proposed vibration criteria to pumps was discussed and studied by a work group in Japan. For the assessment, the data of vibration level in field were measured, and the effects of driver output, rotational speed, and pump type were studied. This paper describes the applicability of the new ISO criteria to the evaluation of vibration level of pumps, based on the results of the field measurements. It was found that the new boundaries of evaluation zones, which are acceptable for unrestricted long-term operation of pumps, are quite appropriate and satisfactory.

scholarly journals Prenatal and perinatal factors influencing nociception, addiction and behavior during ontogenetic development

2008 ◽  
pp. S79-S88
Author(s):  
R Rokyta ◽  
A Yamamotová ◽  
R Šlamberová ◽  
M Franěk ◽  
Š Vaculín ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Postnatal Period ◽  
Long Term Effects ◽  
Perinatal Factors ◽  
Adult Rats ◽  
Factors Affecting ◽  
Dorsal Rhizotomy ◽  
Rat Pups ◽  
Factors Influencing

This review, which summarizes our findings concerning the long-term effects of pre-, peri- and postnatal factors affecting development, nociception and sensorimotor functions, focuses on three areas: 1) perinatal factors influencing nociception in adult rats were examined in rats with hippocampal lesions, after the administration of stress influencing and psychostimulant drugs (dexamethasone, indomethacine and methamphetamine); 2) the effect of pre- and early postnatal methamphetamine administration was shown to impair the development of sensorimotor functions tested in rat pups throughout the preweaning period; 3) the effect of extensive dorsal rhizotomy of the brachial plexus during the early postnatal period was studied with respect to neuropathic pain development and sensorimotor functions. The present study indicates that prenatal or neonatal stress, as well as various drugs, may disturb the development of the nociceptive system and cause long-term behavioral changes persisting to adulthood and that some types of neuropathic pain cannot be induced during the first two postnatal weeks at all. A mature nervous system is required for the development of the described pathological behaviors.

Factors Influencing Radial Artery Size

2007 ◽  
Vol 15 (4) ◽  
pp. 324-326 ◽  
Author(s):  
Yee Jim Loh ◽  
Masakazu Nakao ◽  
Wei Ding Tan ◽  
Chong Hee Lim ◽  
Yong Seng Tan ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Renal Disease ◽  
Radial Artery ◽  
Coronary Arteries ◽  
Duplex Ultrasonography ◽  
Factors Affecting ◽  
Factors Influencing ◽  
The Mean

Size matching of radial artery conduits to coronary arteries is important as it affects the long-term patency. However, factors affecting radial artery size have not been adequately investigated. We retrospectively reviewed 327 consecutive patients who had duplex ultrasonography of their radial arteries over a 2-year period. There were 225 men and 102 women. The mean radial artery size was 2.45 ± 0.54 mm. The factors found to positively affect the size of the radial artery were sex, hypertension, and hyperlipidemia. Diabetes mellitus and age were found to negatively affect radial artery size. Renal disease, race, and smoking did not significantly influence the size of the radial artery. However, as the R squared of this model was insignificant, further studies need to be undertaken to determine other factors that may influence radial artery size.

Fatigue Cracking Processes of a Thick-Walled Component of a Chemical Pipeline

2013 ◽  
Vol 586 ◽  
pp. 104-107 ◽  
Author(s):  
Marek Cieśla ◽  
Kazimierz Mutwil
Keyword(s):  
Mechanical Properties ◽  
Degradation Mechanism ◽  
Fatigue Cracking ◽  
Operating Conditions ◽  
Material Structure ◽  
Mechanical Loads ◽  
Factors Affecting ◽  
Term Operation ◽  
Materials Used

At present, there are no generally accepted and widely recognized procedures to determine condition of material of devices subject to complex long-term thermo-mechanical loads. Condition of pipeline material usually changes when subjected to the conditions of long-term operation. Its structure changes and, consequently, so do its mechanical properties, including fatigue characteristics and crack resistance. Therefore, the durability of a component operating under thermal and mechanical loads cannot be discussed separately from its current material properties. This applies in particular to changes that take place in the material micro-structure and to their connection with mechanical properties. This paper covers analyses of stress in the material of a selected pipeline component – pipe tee that is used in chemical plants. Thermo-mechanical interactions determining stress distribution in the component have been taken into account in the calculations. Morphology and location of the cracks indicated that a fatigue-like nature of impacts was the cause of material destruction. Loads of this type occur mainly in conditions of start-up and shut-down. For these reasons, condition of the material in the above-mentioned unstable conditions was subjected to numerical stress analysis. Due to geometric complexity of the pipeline, the distribution of stress in the T-pipe was calculated in two stages: the object was modeled from a global and local perspective. The resulting stress distributions helped to determine factors affecting durability of the tested object. Metallurgy tests were also conducted in order to ascertain factors determining the degradation of material structure and processes of crack formation and development. As a result of research one ascertained that the process of T-pipe cracking under operating conditions was a combined effect of thermo-mechanical and chemical actions determined by the course of intercrystalline corrosion. Synergic interaction of corrosion processes and variable thermal and mechanical loads caused nucleation and propagation of cracks. The crack systems in T-pipe areas subject to the highest stress showed courses characteristic for thermal fatigue of material. The results obtained will identify degradation mechanism of materials used in chemical installations.

scholarly journals Influence of roundness deviation value on bearing vibration level

2018 ◽  
Vol 19 (12) ◽  
pp. 277-281 ◽  
Author(s):  
Bartłomiej Ambrożkiewicz ◽  
Krzysztof Przystupa ◽  
Sylwester Wnuk
Keyword(s):  
Linear Regression ◽  
Technological Process ◽  
Correlation Coefficients ◽  
Vibration Level ◽  
Pearson’S Correlation ◽  
Rolling Surface ◽  
Shape Errors ◽  
Pearson's Correlation ◽  
Roundness Deviation ◽  
Bearing Vibration

This article investigates the influence of roundness value on vibration level generated by bearing. One of the shape errors playing a key role in bearing’s operation is roundness deviation. Its value directly influence on vibration level generated by bearing. In the paper, the significance and methodology of roundness measurements in reference to profile of rolling surface received in technological process. Experiment consisted of inner rings matching of bearing 6009C3 with variable roundness deviation with outer rings characterized with little variability of mentioned deviation. In the next step bearing vibration level was examined. In the end, obtained results were combined with values of roundness deviation and basing on them, models of linear regression were obtained, also Pearson’s correlation coefficients were calculated.

scholarly journals Long-Term Oxygen Therapy in COPD: Factors Affecting and Ways of Improving Patient Compliance

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Stamatis Katsenos ◽  
Stavros H. Constantopoulos
Keyword(s):  
Oxygen Therapy ◽  
Clinical Effectiveness ◽  
Review Article ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Factors Affecting ◽  
Factors Influencing ◽  
Copd Patients ◽  
Long Term Oxygen Therapy

Long-term oxygen therapy (LTOT) is the cornerstone mode of treatment in patients with severe chronic obstructive pulmonary disease (COPD) associated with resting hypoxaemia. When appropriately prescribed and correctly used, LTOT has clearly been shown to improve survival in hypoxemic COPD patients. Adherence to LTOT ranges from 45% to 70% and utilization for more than 15 hours per day is widely accepted as efficacious. Although several studies have addressed the level of patients' adherence to LTOT, few have suggested or evaluated interventions that conduce to compliance enhancement. The lack of sufficient data regarding COPD patients following oxygen prescription is an enormous void that must be duly confronted to augment clinical effectiveness and cost containment for the long term use. The present review article highlights factors influencing the compliance of patients using LTOT and emphasizes novel strategies and interventions that may prove to be of significant benefit given the remarkably little current research appraising this issue. Therefore, additional research should be promptly performed to verify the efficacy of newly designed approaches in improving the outcomes of patients receiving LTOT.

Sign in / Sign up

Export Citation Format

Share Document