Construction of conical axoids on the basis of congruent spherical ellipses

2022 ◽  
Vol 113 (1) ◽  
pp. 13-18
Author(s):  
T. Kresan ◽  
S. Pylypaka ◽  
Z. Ruzhylo ◽  
C. Rogovskii ◽  
O. Trokhaniak

Purpose: To carry out the transition from a cylindrical gear in which the centroids are congruent ellipses with centres of rotation in the foci, to a bevel gear on the basic of congruent spherical ellipses. Design/methodology/approach: Congruent ellipses with centres of rotation in the foci serve as centroids for the design of cylindrical gears with non-circular wheels. The article analytically shows that the analogues of ellipses on the plane - congruent spherical ellipses are the basis for the construction of the axoids of the corresponding bevel gears. An analogue of the centre-to-centre distance for ellipses in the plane is the angle between the axes of rotation of conical axoids. Findings: Based on the equality of the arcs of ellipses, the dependence of the angle of rotation of one axoid on the angle of rotation of another is found. Graphs of this dependence for separate cases are given. It is shown under what conditions the axes of axoids intersect at right angle. The parametric equations of spherical ellipses and corresponding axoids are given. They were used to construct spherical ellipses and corresponding conical axoids for different cases. For gears with right angle between the axes, separate positions of the axoids with different angles of their rotation around their axes are constructed. Practical implications: Spherical ellipses are directing curves for the construction of the corresponding conical axoids. Originality/value: The paper shows that congruent spherical ellipses act as centroids for the design of axoids of bevel gears. They roll one by one without sliding, rotating around axes that intersect in the centre of the sphere. To design such gears, it is important to know the interdependence between the geometric parameters, especially for common gears with a right angle between the axes.

Author(s):  
Francisco J. Clemente‐Fernández ◽  
Juan Monzó‐Cabrera ◽  
Juan L. Pedreño‐Molina ◽  
Antonio J. Lozano‐Guerrero ◽  
Alejandro Díaz‐Morcillo

PurposeThe purpose of this paper is to analyze the limitations of conventional reactive and resistive filters employed in the open ports of microwave‐heating applicators, in order to know the limits of these filters as a function of the permittivity of the inner materials.Design/methodology/approachCST Studio Suite™ commercial electromagnetic software has been employed to simulate the behaviour of singly and doubly corrugated reactive filters. Additionally, several configurations for resistive filters implemented with water are assessed. Optimization procedures based on genetic algorithms have been used by modifying some geometric parameters of the filters in order to obtain the best possible bandstop response.FindingsResults show the serious limitations of these filters depending on the electric permittivity of the inner materials.Practical implicationsThese limitations restrict the type of the materials that can be processed, so there is a need for new structures which solve these problems.Originality/valueAlthough extensively used in many applications, there are few works that analyze the behaviour of these filters as a function of the geometric parameters or the sample permittivity, and therefore this influence needs to be studied.


Author(s):  
B.A. Lopatin ◽  
◽  
S.V. Plotnikova ◽  
I.P. Deryabin ◽  
◽  
...  

When designing modern machine drives based on traditional gears, in some cases there are problems associated with the complexity of the rational layout of the drive, and its load capacity. These problems can be solved using gears with involute bevel wheels. The involute bevel gear (IBG) is the most common case of gearwheel with an involute tooth profile. In IBG, when teeth are formed, the tool displacement coefficient varies linearly along the width of the gear rim. The geometry of the IBG and the gears made up of them was developed at the Department of Technical Mechanics, a branch of SUSU in Zlatoust. The article presents the main dependencies necessary for determining the size of the IBG and possible schemes for the formation of gears with the IBG. Gearings on the base can be formed at any position of the axles of the gears in space. This paper presents schemes for the formation of spatial (on intersecting axes), bevel (on intersecting axes), cylindrical (on parallel axes) transmissions with IBG. The advantages of gears with IBG (layout, operational, load) in relation to gears from traditional cylindrical and bevel wheels are shown. Thus, transmissions from the IBG on intersecting axes make it possible to transmit rotation at arbitrarily small distancesbetween the axles of the wheels with the required contact localization, up to obtaining a linearcontact in gearing of the teeth. Bevel gears with IBG are less sensitive to errors and can be formed at small interaxial angles, which is problematic for traditional bevel gears. Cylindrical gears with IBG differ from traditional ones in increased load capacity and smooth operation. In addition, they can be used as backlashless and single-sided gears. Thus, gears with IBG due totheir versatility and advantages over traditional gears can be successfully used in modern drives(aviation, space, automobile, etc.) with any arrangement of gear axles in space.


2019 ◽  
Vol 32 (4) ◽  
pp. 455-471
Author(s):  
Jorge Cruz-Cárdenas ◽  
Jorge Guadalupe-Lanas ◽  
Ekaterina Zabelina ◽  
Andrés Palacio-Fierro ◽  
Margarita Velín-Fárez ◽  
...  

Purpose The purpose of this paper is to understand in-depth how consumers create value in their lives using WhatsApp, the leading mobile instant messaging (MIM) application. Design/methodology/approach The study adopts the perspective of customer-dominant logic (CDL) and uses a qualitative multimethod design involving 3 focus groups and 25 subsequent in-depth interviews. The research setting was Ecuador, a Latin American country. Findings Analysis and interpretation of the participants’ stories made it possible to identify and understand the creation of four types of value: maintaining and strengthening relationships; improving role performance; emotional support; and entertainment and fun. In addition, the present study proposes a conceptual model of consumer value creation as it applies to MIM. Practical implications Understanding the way consumers create value in their lives using MIM is important not only for organizations that offer MIM applications, but also for those companies that develop other applications for mobile phones or for those who wish to use MIM as an electronic word-of-mouth vehicle. Originality/value The current study is one of the first to address the topic of consumer behavior in the use of technologies from the perspective of CDL; this perspective enables an integrated qualitative vision of value creation in which the consumer is the protagonist.


2019 ◽  
Vol 25 (3) ◽  
pp. 378-396 ◽  
Author(s):  
Arian Razmi-Farooji ◽  
Hanna Kropsu-Vehkaperä ◽  
Janne Härkönen ◽  
Harri Haapasalo

Purpose The purpose of this paper is twofold: first, to understand data management challenges in e-maintenance systems from a holistically viewpoint through summarizing the earlier scattered research in the field, and second, to present a conceptual approach for addressing these challenges in practice. Design/methodology/approach The study is realized as a combination of a literature review and by the means of analyzing the practices on an industry leader in manufacturing and maintenance services. Findings This research provides a general understanding over data management challenges in e-maintenance and summarizes their associated proposed solutions. In addition, this paper lists and exemplifies different types and sources of data which can be collected in e-maintenance, across different organizational levels. Analyzing the data management practices of an e-maintenance industry leader provides a conceptual approach to address identified challenges in practice. Research limitations/implications Since this paper is based on studying the practices of a single company, it might be limited to generalize the results. Future research topics can focus on each of mentioned data management challenges and also validate the applicability of presented model in other companies and industries. Practical implications Understanding the e-maintenance-related challenges helps maintenance managers and other involved stakeholders in e-maintenance systems to better solve the challenges. Originality/value The so-far literature on e-maintenance has been studied with narrow focus to data and data management in e-maintenance appears as one of the less studied topics in the literature. This research paper contributes to e-maintenance by highlighting the deficiencies of the discussion surrounding the perspectives of data management in e-maintenance by studying all common data management challenges and listing different types of data which need to be acquired in e-maintenance systems.


2020 ◽  
Vol 27 (3) ◽  
pp. 755-770
Author(s):  
Maria Krambia-Kapardis

Purpose The purpose of this study is to develop a profile of whistleblowers and to determine whether whistleblowing legislation would encourage those individuals to bring to light some illegal or unethical behaviour that otherwise would remain in the shadows. Design/methodology/approach Having identified whistleblowing correlation, a survey was carried out in Cyprus of actual whistleblowers and could-have-been whistleblowers. Findings Males between 46 and55 years of age, regardless of whether they have dependents or hold senior positions in organizations are significantly more likely to blow the whistle. However, could-have-been whistleblowers did not go ahead because they felt that the authorities would not act on their information. Research limitations/implications Because of the sensitive nature of the research topic and the fact that only whistleblowers or intended whistleblowers could participate in the study, the sample size is limited as a result. This, in turn, limits both the number of respondents in each category (actual and intended) as well as constrains the statistical analysis that could be carried out on the data. Practical implications It remains to be seen whether EU Member States shall implement the European Directive 2019/1937 on the protection of persons who report breaches of Union Law, in its entirety by the due date, namely December 2021. Originality/value This study provides a literature review of whistleblowing and reports an original survey against the backdrop of the European Directive.


2020 ◽  
Vol 36 (8) ◽  
pp. 29-31

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings The problem with developing a reputation of being something of an oracle in the business world is that all of a sudden, everyone expects you to pull off the trick of interpreting the future on a daily basis. Like a freak show circus act or one-hit wonder pop singer, people expect you to perform when they see you, and they expect you to perform the thing that made you famous, even if it is the one thing in the world you don’t want to do. And when you fail to deliver on these heightened expectations, you are dismissed as a one trick pony, however good that trick is in the first place. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.


2020 ◽  
Vol 33 (8) ◽  
pp. 2053-2076 ◽  
Author(s):  
Osamuyimen Egbon ◽  
Chijoke Oscar Mgbame

PurposeThe paper examines how oil multinational companies (MNCs) in Nigeria framed accounts to dissociate themselves from causing oil spills.Design/methodology/approachThe authors utilised data from relevant corporate reports, external accounts and interviews, and used sensegiving with defensive behaviours theoretical framing to explore corporate narratives aimed at altering stakeholders' perceptions.FindingsThe corporations gave sense to their audience by invoking scapegoating blame avoidance narrative in attributing the cause of most oil spills in Nigeria to outsiders (sabotage), despite potentially misclassifying the sabotage-corrosion dichotomy. Corporate stance was reinforced through justifying narrative, which suggested that multi-stakeholders jointly determined the causes of oil spills, thus portraying corporate accounts as transparent, credible and objective.Research limitations/implicationsThe socio-political dynamics in an empirical setting affect corporate accounts and how those accounts appear persuasive, implying that such contextual factors merit consideration when evaluating corporate accounts. For example, despite contradictions in corporate accounts, corporate attribution of oil spills to external factors appeared persuasive due to the inherently complicated socio-political dynamics.Practical implicationsWith compensation to oil spills' victims only legally permitted for non-sabotage-induced spills alongside the burden of proof on the victims, the MNCs are incentivised to attribute most oil spills to sabotage. On policy implication, accountability would be best served when the MNCs are tasked both with the burden of proof and a responsibility to demonstrate their transparency in preventing oil spills, including those caused by sabotage.Originality/valueCrisis situations generate multiple and competing perspectives, but sensegiving and defensive behaviours lenses enrich our understanding of how crisis-ridden companies frame narratives to alter stakeholders' perceptions. Accounts-giving therefore partly satisfies accountability demands, and acts as sensegiving signals aimed at reframing/redefining existing perceptions.


2018 ◽  
Vol 19 (4) ◽  
pp. 1-3
Author(s):  
Robert Van Grover

Purpose To summarize and interpret a Risk Alert issued on April 12, 2018 by the US SEC’s Office of Compliance Inspections and Examinations (OCIE) on the most frequent advisory fee and expense compliance issues identified in recent examinations of investment advisers. Design/methodology/approach Summarizes deficiencies identified by the OCIE staff pertaining to advisory fees and expenses in the following categories: fee billing based on incorrect account valuations, billing fees in advance or with improper frequency, applying incorrect fee rates, omitting rebates and applying discounts incorrectly, disclosure issues involving advisory fees, and adviser expense misallocations. Findings In the Risk Alert, OCIE staff emphasized the importance of disclosures regarding advisory fees and expenses to the ability of clients to make informed decisions, including whether or not to engage or retain an adviser. Practical implications In light of the issues identified in the Risk Alert, advisers should assess the accuracy of disclosures and adequacy of policies and procedures regarding advisory fee billing and expenses. As a matter of best practice, advisers should implement periodic forensic reviews of billing practices to identify and correct issues relating to fee billing and expenses. Originality/value Expert guidance from experienced investment management lawyer.


Author(s):  
Paul Ranson ◽  
Daniel Guttentag

Purpose This study aimed to investigate whether increasing the social presence within an Airbnb lodging environment could nudge guests toward altruistic cleaning behaviors. Design/methodology/approach The study was based around a theoretical framework combining the social-market versus money-market relationship model, nudge theory and social presence theory. A series of three field experiments were conducted, in which social presence was manipulated to test its impact on guest cleaning behaviors prior to departure. Findings The experimental results confirmed the underlying hypothesis that an Airbnb listing’s enhanced social presence can subtly induce guests to help clean their rental units prior to departure. Originality/value This study is the first to examine behavioral nudging in an Airbnb context. It is also one of the first field experiments involving Airbnb. The study findings offer clear theoretical and practical implications.


2015 ◽  
Vol 4 (4) ◽  
pp. 423-433
Author(s):  
Paul B. Spooner

Purpose – For over a 100 years, Macau’s Pataca has been tied to Macau’s identity, its independent financial existence and its links to the Lusophone world. Its role as a supporter of the Macau identity relies upon the strength and capabilities of its financial institutions, the Macau Monetary Authority and banking institutions that issue its currency (Banco Nacional Ultramarino and Bank of China). The paper aims to discuss the above issue. Design/methodology/approach – The author uses statistics and data from the Macau Monetary Authority. Findings – There are three possible scenarios that could emerge: first, retired in favor of the RMB, the HK dollar; second, maintained with its use expanding as Macau’s revenues and investment funds grow, or third, become a force for stronger economic cohesion and identity among the Lusophone nations. Practical implications – Which of these scenarios will offer Macau the highest possibility of maintaining its international network of relationships and representation, diversifying its economy into new growth markets and playing a unique role in China’s twenty-first century destiny? Originality/value – This paper studies a rarely discussed topic and focuses on a core component of Macau’s existence.


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