Design and fast verification of pocket elliptical journal bearings

2014 ◽  
Vol 66 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Fabrizio Stefani

Purpose – The purpose of this paper was to conceive a fast method to verify design and performance of elliptical pocket journal bearings. Design/methodology/approach – The computer-aided verification of pocket journal bearings is performed by means of a suitable finite element analysis method. Findings – The results of sample analyses indicate that the machining tolerances are very influential on elliptical pocket bearing performances, and they must be included among the input data. Originality/value – Although elliptical pocket bearings are widely used in turbomachineries, the influence of their design on performance has not been specifically investigated. A lot of works about tribological models are available, but few of them focus on their application to bearing design at the industrial level.

Sensor Review ◽  
2017 ◽  
Vol 37 (1) ◽  
pp. 26-32
Author(s):  
Hanshan Li

Purpose The purpose of this paper is to evaluate the detection performance of infrared photoelectric detection system and establish stable tracking platform. Design/methodology/approach This paper puts forward making use of the finite element analysis method to set up the infrared radiation characteristics calculation model of flying target in infrared photoelectric detection system; researches the target optical characteristics based on the target imaging detection theory; sets up the heat balance equation of target’s surface node and gives the calculation method of total radiation intensity of flying target; and deduces the target detection distance calculation function; studies the changed regulation of radiation energy that charge coupled device (CCD) gain comes from target surface infrared heat radiations under different sky background luminance and different target flight attitude. Findings Through calculation and experiment analysis, the results show that when the target’s surface area increases or the target flight velocity is higher, the radiation energy that CCD obtained is higher, which is advantageous to the target stable detection in infrared photoelectric detection system. Originality/value This paper uses the finite element analysis method to set up the infrared radiation characteristics calculation model of flying target and give the calculation and experiment results; those results can provide some data and improve the design method of infrared photoelectric detection system, and it is of value.


2012 ◽  
Vol 152-154 ◽  
pp. 1774-1778 ◽  
Author(s):  
Wen Rui Wang ◽  
Zhi Hui Sun ◽  
Xiao Qiang Yan ◽  
Qi Jiang

Based on the performance of Vane hydraulic damp O-ring seal ,simulation about the O-ring seal was applied by nonlinear finite element analysis method. The factors influencing sealing performance are considered, such as initial compressibility, sealing materials. Applying the method, the seal structure was designed and optimized. At the same time, the sealing performance was improved, and the contract pressure was increased. The finite element analysis method can be effectively used to solve nonlinear material and sealing failure problem for the seal design, optimization and performance analysis, which provide a new approach and theoretical guidance to the rubber seal research. The seal material and compression ratio are both great influence on the sealing performance , which should be based on working conditions to select the appropriate sealing materials.


2018 ◽  
Vol 55 (4) ◽  
pp. 666-675
Author(s):  
Mihaela Tanase ◽  
Dan Florin Nitoi ◽  
Marina Melescanu Imre ◽  
Dorin Ionescu ◽  
Laura Raducu ◽  
...  

The purpose of this study was to determinate , using the Finite Element Analysis Method, the mechanical stress in a solid body , temporary molar restored with the self-curing GC material. The originality of our study consisted in using an accurate structural model and applying a concentrated force and a uniformly distributed pressure. Molar structure was meshed in a Solid Type 45 and the output data were obtained using the ANSYS software. The practical predictions can be made about the behavior of different restorations materials.


2017 ◽  
Vol 8 (4) ◽  
pp. 558-577 ◽  
Author(s):  
Faiza Khan ◽  
Michelle Callanan

Purpose The purpose of this paper is to address the confusing use of terminology associated with tourism undertaken by Muslims and to identify key concerns associated with this type of tourism. Design/methodology/approach This is an exploratory study and adopts a critical review of literature following the evolutionary concept analysis method. Content analysis of popular UK media, UK-based tour operators’ websites and tourism strategies of destinations popular with Muslim tourists were conducted to examine the use of terminology. Findings There is no clear difference between the various terms (halal, Muslim friendly, Islamic, etc.) used. Overall, academia uses the term Islamic tourism, while the industry and media use various terms. Among destinations, however, there is no clear and consistent use of terminology. A key concern of Islamic tourism is the role of certification in assuring travellers and the lack of standardisation of halal certification. Research limitations/implications The paper is based on literature review and secondary data analysis. It lacks primary research. Practical implications This study highlights the need for consistent use of terminology across industry. Another implication is the issue surrounding halal certification of food and the importance of trust in the seller/service provide. Another trend that industry providers need to consider is the growth of the Muslim millennial traveller and the needs of this market segment. Originality/value The paper highlights the importance of studying the Muslim tourist market and provides a starting point for further research. It highlights several issues such as the need to develop a typology of Muslim tourists. Of particular interest is the concern whether halal values in danger of being commodified in the absence of a universal agreed criterion for halal certification.


2017 ◽  
Vol 16 (4) ◽  
pp. 155-160
Author(s):  
Ian Johnston

Purpose This paper aims to show that everything a business does is fundamentally reliant on its culture. Culture determines how successful a strategy is and whether that strategy can be executed. If the culture in a business is out of alignment, it is imperative to change it. This paper examines how HR professionals can take ownership of this cultural space and help to create a growth mindset throughout the organisation. Design/methodology/approach The paper is based on experience gained through working with several large organisations to transform their people culture and performance by embracing a growth mindset and to help their HR leadership become the early champions of change, thus ensuring the process was successfully delivered. The paper includes case studies of two organisations where successful cultural shaping delivered improved results. Findings Companies with a growth mindset will outperform those with a fixed mindset. Changing mindsets is not overly complex, but it requires flawless implementation with the HR leaders at the forefront. Originality/value As Lou Gerstner, who turned around the computing giant IBM, said “I finally realised that culture is not part of the game, it is the game”. By understanding how individual mindsets impact culture, HR professionals can own and drive their organisation’s culture-shaping efforts.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hossein Motahari-Nezhad ◽  
Maryam Shekofteh ◽  
Maryam Andalib-Kondori

Purpose This study aims to investigate the characteristics, as well as the purpose and posts of the COVID-19 Facebook groups. Design/methodology/approach A systematic search for COVID-19 Facebook groups was conducted on June 1, 2020. Characteristics of the groups were examined using descriptive statistics. Mann-Whitney test was used to study the differences between groups. The study of the most popular groups’ posts was also carried out using the content analysis method. Findings The groups had a combined membership of 2,729,061 users. A total of 147,885 posts were received. There were about approximately 60% public groups. A high percentage of the groups (86.5%) had descriptions. The results showed a significant relationship between the groups’ description status and the number of members (p-value = 0.016). The majority of COVID-19 Facebook groups (56%) were created to meet their members’ information needs. The highest number of studied posts were related to vaccination (35.2%), followed by curfew rules (19.6%) and symptoms (10.6%). Originality/value Translating these insights into policies and practices will put policymakers and health-care providers in a stronger position to make better use of Facebook groups to support and enhance public knowledge about COVID-19.


2019 ◽  
Vol 10 (3) ◽  
pp. 743-766
Author(s):  
Anete Petrusch ◽  
Guilherme Luís Roehe Vaccaro ◽  
Juliane Luchese

Purpose Although discussed for more than 20 years, information about Lean adoption in higher education institutions (HEIs) is scarce, especially in developing countries. This research aims to investigate the degree of Lean thinking adoption on administrative services of Brazilian private HEIs. The results are compared to studies from USA and UK, highlighting the maturity on enablers, principles, tools and performance measures related to Lean. Design/methodology/approach A quantitative survey research was carried out. The instrument is adapted for HEIs from the proposal of Malmbrandt and Åhlström (2013) for Lean services. Cronbach’s alpha and factor analysis were used to validate the adapted instrument. Additional data analysis was based on non-parametric tests. Findings No evidence of broad implementation of Lean thinking in administrative processes of Brazilian private HEIs was found, with the adoption being incipient. The results are convergent to those presented by other studies in the USA and the UK. There is a gap between the existing knowledge about Lean in the academic sphere of the HEIs and its application on their academic processes. Research limitations/implications The effective sample size was of 47, despite contacts being sent to 2,090 institutions. This sample allows exploratory research, although further research is required. Results are adherent to those found in research from other countries. Originality/value The research presents descriptive and exploratory results regarding the adoption of Lean in Brazilian HEIs. No previous similar research was found in the literature.


2017 ◽  
Vol 24 (5) ◽  
pp. 809-827 ◽  
Author(s):  
Ahmed Ebrahim Abu El-Maaty ◽  
Amr M. El-Kholy ◽  
Ahmed Yousry Akal

Purpose Modeling represents the art of translating problems from an application area into tractable mathematical formulations whose theoretical and numerical analysis provides insight, answers and guidance useful for the originating application. The purpose of this paper is to determine the causal causes of schedule overrun and cost escalation of highway projects in Egypt in order to be used as independents variables in mathematical models for predicting the percentages of schedule overrun and cost escalation of such projects in Egypt. Design/methodology/approach A survey of a randomly selected samples yielded responses from 40 owners, 15 consultants and 56 contractors. The survey includes 38 schedule overrun factors and 26 cost escalation factors. The effectiveness degree of the identified factors has been identified by the triangle fuzzy approach. Findings The results of the survey show that “contractor’s technical staff is insufficient and ineligible to accomplish the project” is the most important cause of schedule overrun, while the major cause of cost escalation is inadequate preparation of the project concerning planning and execution. Originality/value The main contribution of this study is predicting the percentages of schedule overrun and cost escalation of highway projects in Egypt. Through the application of the linear regression analysis method and statistical fuzzy theory, four predictive models have been developed and it has been noted that the linear regression-based model shows prediction accuracy better than statistical fuzzy-based model in predicting percentages of schedule overrun and cost escalation.


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