An analytical model of the replacement costs of aircraft engine life-limited parts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Branimir Stojiljković ◽  
Ljubiša Vasov ◽  
Olja Čokorilo ◽  
Goran Vorotović
Keyword(s):  
Management Strategies ◽  
Aircraft Engine ◽  
List Price ◽  
Content Type ◽  
Academic Literature ◽  
Replacement Decisions ◽  
Cost Forecasting ◽  
Number Of Cycles ◽  
Engine Life ◽  
List Prices

Purpose The purpose of this paper is to present novel recursive expressions for modelling the replacement costs of aircraft engine life-limited parts during shop visits to assist engine operators in both evaluating their decisions regarding the applied life-limited parts management strategies and tracking the replacement costs consistently throughout the life of the engine. Design/methodology/approach The replacement costs of aircraft engine life-limited parts are modelled analytically in this research, which strives to quantify the costs of used and unused lives of the replaced parts, incurred during engine shop visit events. Inputs for this model include the list price of life-limited parts, the replacement decisions made on all previous shop visits and the number of cycles the engine has operated at different thrust ratings on all previous operating intervals. Findings The average annual escalation rate of life-limited parts list prices was shown to range from 5% to 7%. The presented model is not only suitable for calculating the costs of used and unused lives of life-limited parts during past engine shop visit events but also for application in the life-limited parts replacement cost forecasting and optimisation models. Originality/value Uniquely derived recursive expressions represent the final result of the developed model which, to the authors’ knowledge, had not been studied elsewhere in the academic literature. The analysis of aircraft engine life-limited part list prices carried out to account for the average annual escalation rate enables the prediction of replacement costs during subsequent shop visits.

scholarly journals Overcoming the capital investment hurdle in worker-controlled firms

2019 ◽  
Vol 2 (2) ◽  
pp. 133-150
Author(s):  
Guy Major ◽  
Jonathan Preminger
Keyword(s):  
Capital Investment ◽  
Value Added ◽  
Employee Ownership ◽  
Workplace Democracy ◽  
Equity Investment ◽  
Content Type ◽  
Academic Literature ◽  
Worker Ownership ◽  
Significant Step ◽  
Average Worker

Purpose Both the academic literature and practitioners have long noted the need for an equity investment mechanism for worker-controlled firms that alleviates investor anxieties without undermining internal workplace democracy. The purpose of this paper is to outline one such possible mechanism. Design/methodology/approach The proposal locks together the interests of workers and external investors, via non-voting shares with dividends set by a pre-agreed value-added sharing formula. Each worker is paid a base wage, with the average across the firm being a pre-defined multiple of the national minimum wage. Any additional surplus is split into a number of equal “slices”, with each share receiving one slice as its dividend, and the average worker receiving a pre-agreed number of slices as a bonus. Findings Workers have an incentive to maximise their own incomes, and in so doing, will also automatically maximise the dividends received by investors, obviating the need for the shares to have normal voting rights. Working on this principle of aligned interests, the authors also discuss reinvestment, worker ownership of non-voting shares and possibilities for a secondary share market. The authors show how this proposal will be a significant step in aligning the interests of investors with owner-workers in a democratic, negotiated way that shares both risk and returns, thus making worker-controlled firms more attractive to equity investment. Originality/value In light of the recognised problem of underinvestment in worker-controlled firms and the risk of their degeneration, this paper will interest both academics and practitioners in employee ownership, co-operatives and various forms of workplace democracy.

Knowledge management strategies for sustaining Lesson Study

2019 ◽  
Vol 9 (2) ◽  
pp. 167-178
Author(s):  
Eric C.K. Cheng
Keyword(s):  
Information Technology ◽  
Knowledge Management ◽  
Hong Kong ◽  
Knowledge Sharing ◽  
Lesson Study ◽  
Structural Equation ◽  
Explicit Knowledge ◽  
Relative Effectiveness ◽  
Management Strategies ◽  
Content Type

Purpose The purpose of this paper is explore the relative effectiveness of people-based and information technology-based knowledge management (KM) strategies as implemented by principals in Hong Kong schools to facilitate and sustain Lesson Study for teachers’ knowledge sharing and internalization. Design/methodology/approach Data from 184 principals in Hong Kong were collected by a cross-sectional quantitative survey. Confirmatory factor analysis and reliability tests have been used to examine the constructed validity and reliability of the instrument. A structural equation model was applied to confirm the predictive effect of people-based and information technology-based KM strategies on teachers’ knowledge sharing and internalization through Lesson Study. Findings Results show that people-based KM strategy predicts knowledge sharing and internalization by and among teachers. However, while information technology-based knowledge management strategies predict teachers’ knowledge sharing, they do not predict how effectively they internalize knowledge. Practical implications Cultivating communities of practice, professional learning communities and mentoring schemes in schools can nurture a knowledge-sharing culture to facilitate and sustain Lesson Study for teacher learning. Institutionalizing an information technology system can help teachers to retrieve, share and store the school’s explicit knowledge. Originality/value The paper not only suggests school management strategies and practices for school leaders to facilitate and sustain Lesson Study, but also brings a new research dimension, KM, to the research area.

Characteristic properties of AlTiN and TiN coated HSS materials

2015 ◽  
Vol 67 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Mumin Sahin ◽  
Cenk Misirli ◽  
Dervis Özkan
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Wear Properties ◽  
Content Type ◽  
X Ray ◽  
Number Of Cycles ◽  
Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

Innovative management strategies for building and sustaining a digital initiatives department with limited resources

2018 ◽  
Vol 34 (2) ◽  
pp. 117-136 ◽  
Author(s):  
A. Miller
Keyword(s):  
Project Management ◽  
Management Practices ◽  
Management Strategies ◽  
Academic Library ◽  
Collaborative Management ◽  
Strong Line ◽  
Content Type ◽  
Innovative Strategies ◽  
Other Information

Purpose The purpose of this paper is to offer and explore innovative strategies for building and sustaining digital initiatives at information organizations. Although the examples provided are based on case studies at an academic library, the practices are rooted in project management principles and therefore applicable to all library types, museums, archives and other information organizations. The innovative strategies on staffing and funding will be particularly useful to organizations faced with monetary and staffing shortages and highlights collaborative management practices. Design/methodology/approach Concept of strategic and collaborative management practices led by an experienced project manager cross-trained in management, technical and soft skills enables the successful development and sustainability of digital initiatives. A cross-trained librarian’s management practices of leading the Digital Scholarship Initiatives at a particular university will be examined as a case study and aided with literature supporting the need for digital initiatives leaders to have training beyond the credentials of librarian, curator, archivist or historian in the technologically savvy twenty-first century ecology of information centers. Findings The innovative strategies implemented in the case study yielded increases in the number of hours of digital lab usage, digital projects developed, seminars or workshops presented, attendance of library hosted events, number of programs implemented and awareness on campus, all with limited staff and funding. The variety and level of production and marketing is instrumental to the growth and sustainability of digital initiatives. Practical implications The innovative strategies emphasized in this paper use the concept of borrowed or shared time to start staffing needs and is particularly helpful to organizations that do not have a strong line of dedicated staffing or funding to begin building digital initiatives. Offers small ways to start immediately while setting the stage to plan for big ideas for the future. Originality/value This paper suggests a credentialed information expert, such as a librarian, archivist or curator, that is, also cross-trained in project management and technology is the key to not only successfully leading digital initiatives but is instrumental for its sustainability and the marketing, growth and future of digital initiatives.

Passenger aircraft emissions analysis at Ordu-Giresun International Airport, Turkey in 2017

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ilkay Orhan
Keyword(s):  
Aircraft Engine ◽  
Civil Aviation ◽  
Exhaust Emission ◽  
Aircraft Emissions ◽  
Emission Data ◽  
Emission Analysis ◽  
Content Type ◽  
International Airport ◽  
Engine Emission ◽  
The Impact

Purpose The purpose of this study is to present the pollutant gas produced by hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx) and the quantity of fuel burned from commercial aircraft at Ordu-Giresun International Airport, Turkey during the landing and take-off (LTO) cycles in 2017. Design/methodology/approach The flight data recorded by the General Directorate of State Airports Authority and the aircraft engine emission data from International Civil Aviation Organization (ICAO) Engine Exhaust Emission Databank were used for calculation. The aircraft and engine types used by the airlines for flight at Ordu-Giresun International Airport were determined. To evaluate the effect of taxi time on emission amounts, analysis and evaluations were made by taking different taxi times into consideration. Findings As a result of the emission analysis, the amount of fuel consumed by the aircraft were calculated as 6,551.52 t/y, and the emission amounts for CO, HC and NOx were estimated as 66.81, 4.20 and 79.97 t/y, respectively. Practical implications This study is aimed to reveal the effect and contribution of taxi time on the emitted emission at the airport during the LTO phase of the aircraft. Originality/value This study helps aviation authorities explain the importance of developing procedures that ensure the delivery of aircraft to flights in minimum time by raising awareness of the impact of taxi time on emitted emissions, and contributes to the determination of an aircraft emission inventory at Ordu-Giresun International Airport.

Does the second wave of COVID-19 undermine corporate immunity? International evidence

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Huy Viet Hoang ◽  
Cuong Nguyen ◽  
Khanh Hoang
Keyword(s):  
Stock Returns ◽  
Stock Price ◽  
Fixed Effects ◽  
Management Strategies ◽  
The United States ◽  
Least Square ◽  
Content Type ◽  
The Impact ◽  
Second Wave ◽  
Practical Implications

PurposeThis study compares the impact of the COVID-19 pandemic on stock returns in the first two waves of infection across selected markets, given built-in corporate immunity before the global outbreak.Design/methodology/approachThe data are collected from listed firms in five markets that have experienced the second wave of COVID-19 contagion, namely the United States (US), Australia, China, Hong Kong and South Korea. The period of investigation in this study ranges from January 24 to August 28, 2020 to cover the first two COVID-19 waves in selected markets. The study estimates the research model by employing the ordinary least square method with fixed effects to control for the heterogeneity that may confound the empirical outcomes.FindingsThe analysis reveals that firms with larger size and more cash reserves before the COVID-19 outbreak have better stock performance under the first wave; however, these advantages impede stock resilience during the second wave. Corporate governance practices significantly influence stock returns only in the first wave as their effects fade when the second wave emerges. The results also suggest that in economies with greater power distance, although stock price depreciation was milder in the first wave, it is more intense when new cases again surge after the first wave was contained.Practical implicationsThis paper provides practical implications for corporate managers, policymakers and governments concerning crisis management strategies for COVID-19 and future pandemics.Originality/valueThis study is the first to evaluate built-in corporate immunity before the COVID-19 shock under successive contagious waves. Besides, this study accentuates the importance of cultural understanding in weathering the ongoing pandemic across different markets.

Minimisation and management strategies for refurbishment and renovation waste in Hong Kong

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ann T.W. Yu ◽  
Kelvin S.H. Mok ◽  
Irene Wong
Keyword(s):  
Hong Kong ◽  
Data Collection ◽  
Management Strategies ◽  
Government Support ◽  
Construction And Demolition Waste ◽  
Snowball Sampling ◽  
Structured Interviews ◽  
Demolition Waste ◽  
Content Type ◽  
The Government

PurposeThe capacity of landfills will reach saturation in the 2020s. There are more than 50,000 buildings in Hong Kong over 30 years old and which may require extensive refurbishment under the Mandatory Building Scheme. Additionally, most new owners/tenants tend to renovate their premises before moving in. Hence, there is an urgent need in Hong Kong, to explore strategies and measures to enable the development of effective refurbishment and renovation (R&R) waste management for such projects. The objectives of this paper are to investigate the process of R&R for identifying the perceived barriers and thereby the strategies for minimisation and management of R&R waste in Hong Kong.Design/methodology/approachDesktop study, semi-structured interviews, site observations and document reviews were used as the data collection methods to achieve the objectives of this research. Considering the nature and characteristics of the industry structure, the snowball sampling process was deployed for data collection. Thematic analysis and content analysis were used for data analysis. Waste minimisation and management strategies for R&R projects were then discussed and developed by the research team and a focus group meeting was held to validate the research findings. Six strategies were then proposed to the government.FindingsR&R projects contribute 10–20% of the construction and demolition waste. The barriers to recycling of R&R waste can be grouped into six major categories: (1) lack of sorting and storage spaces, (2) high cost, (3) insufficient government supporting policy, (4) complicated recycling processes, (5) immature recycling market and (6) insufficient public education. Also, six strategies are proposed in this study, which include (1) pre-refurbishment audit, (2) development of recycling market, (3) sea reclamation, (4) incineration, (5) government support and (6) education and research.Originality/valueThe strategies and measures proposed in this research could most adequately serve as reference for the government officials, building professionals and academic researchers. Such knowledge would make possible the development of effective strategies and measures for minimising and managing R&R waste.

scholarly journals Examining the spatial relationship between environmental health factors and house prices

2018 ◽  
Vol 11 (3) ◽  
pp. 353-398 ◽  
Author(s):  
Michael J. McCord ◽  
Sean MacIntyre ◽  
Paul Bidanset ◽  
Daniel Lo ◽  
Peadar Davis
Keyword(s):  
Air Quality ◽  
Environmental Quality ◽  
House Prices ◽  
Management Strategies ◽  
Noise Pollution ◽  
Well Being ◽  
Spatial Modelling ◽  
Content Type ◽  
The Impact ◽  
Health And Well Being

Purpose Air quality, noise and proximity to urban infrastructure can arguably have an important impact on the quality of life. Environmental quality (the price of good health) has become a central tenet for consumer choice in urban locales when deciding on a residential neighbourhood. Unlike the market for most tangible goods, the market for environmental quality does not yield an observable per unit price effect. As no explicit price exists for a unit of environmental quality, this paper aims to use the housing market to derive its implicit price and test whether these constituent elements of health and well-being are indeed capitalised into property prices and thus implicitly priced in the market place. Design/methodology/approach A considerable number of studies have used hedonic pricing models by incorporating spatial effects to assess the impact of air quality, noise and proximity to noise pollutants on property market pricing. This study presents a spatial analysis of air quality and noise pollution and their association with house prices, using 2,501 sale transactions for the period 2013. To assess the impact of the pollutants, three different spatial modelling approaches are used, namely, ordinary least squares using spatial dummies, a geographically weighted regression (GWR) and a spatial lag model (SLM). Findings The findings suggest that air quality pollutants have an adverse impact on house prices, which fluctuate across the urban area. The analysis suggests that the noise level does matter, although this varies significantly over the urban setting and varies by source. Originality/value Air quality and environmental noise pollution are important concerns for health and well-being. Noise impact seems to depend not only on the noise intensity to which dwellings are exposed but also on the nature of the noise source. This may suggest the presence of other externalities that arouse social aversion. This research presents an original study utilising advanced spatial modelling approaches. The research has value in further understanding the market impact of environmental factors and in providing findings to support local air zone management strategies, noise abatement and management strategies and is of value to the wider urban planning and public health disciplines.

Business plan competitions in developed and emerging economies

2019 ◽  
Vol 11 (1) ◽  
pp. 81-97 ◽  
Author(s):  
Syed Awais Ahmad Tipu
Keyword(s):  
Emerging Economies ◽  
Business Plan ◽  
Integrated Approach ◽  
Future Research ◽  
Journal Articles ◽  
Research Gaps ◽  
Content Type ◽  
Individual Level ◽  
Academic Literature ◽  
The Individual

Purpose This paper aims to review the academic literature on business plan competitions in developed and emerging economies to assess the contribution to the knowledge so far and identify research gaps. Design/methodology/approach A variety of databases (such as ABI/Inform Global, Academic Search Complete, Business Source Premier and Emerald Full Text) were used to find peer-reviewed journal articles. Regardless of time, different search terms were used to find relevant journal articles such as business plan competitions, business plan contests, business plan teams, business plan judges, business plan development and business plan scores. After a careful review of the identified articles, a total of 22 articles were included in the final review. The articles in the final set were manually coded using the thematic codes. Findings Despite the popularity of business plan competitions, limited academic literature exists, particularly in the context of emerging economies. A total of 16 out of 22 studies are conducted in developed economies. The findings suggest that the literature on business plan competitions is largely centered on the structure of business plan competitions, the characteristics of the participating teams and the benefits of business plan competitions. The individual level benefits of business plan competitions include the development of entrepreneurial skills, opportunity for networking and access to mentors. Business plan competitions can be better aligned with public policy, particularly in case of emerging economies. Therefore, a more focused and integrated approach among industry, academia and government in encouraging business plan competitions could potentially make a far-reaching impact in establishing an enterprising society. While much is known about the structure and the benefits of business plan competitions, there are various research gaps which need to be addressed. Originality/value The current paper is the first identifiable review of the literature on business plan competitions. The proposed questions for future research will potentially help in addressing the identified research gaps.

Unification proposals for fatigue crack propagation laws

2017 ◽  
Vol 13 (2) ◽  
pp. 262-283 ◽  
Author(s):  
Vladimir Kobelev
Keyword(s):  
Differential Equation ◽  
Crack Propagation ◽  
Crack Length ◽  
Closed Form ◽  
Crack Growth ◽  
Stress Ratio ◽  
Elementary Functions ◽  
Content Type ◽  
Number Of Cycles ◽  
Cycles To Failure

Purpose The purpose of this paper is to propose the new dependences of cycles to failure for a given initial crack length upon the stress amplitude in the linear fracture approach. The anticipated unified propagation function describes the infinitesimal crack-length growths per increasing number of load cycles, supposing that the load ratio remains constant over the load history. Two unification functions with different number of fitting parameters are proposed. On one hand, the closed-form analytical solutions facilitate the universal fitting of the constants of the fatigue law over all stages of fatigue. On the other hand, the closed-form solution eases the application of the fatigue law, because the solution of nonlinear differential equation turns out to be dispensable. The main advantage of the proposed functions is the possibility of having closed-form analytical solutions for the unified crack growth law. Moreover, the mean stress dependence is the immediate consequence of the proposed law. The corresponding formulas for crack length over the number of cycles are derived. Design/methodology/approach In this paper, the method of representation of crack propagation functions through appropriate elementary functions is employed. The choice of the elementary functions is motivated by the phenomenological data and covers a broad region of possible parameters. With the introduced crack propagation functions, differential equations describing the crack propagation are solved rigorously. Findings The resulting closed-form solutions allow the evaluation of crack propagation histories on one hand, and the effects of stress ratio on crack propagation on the other hand. The explicit formulas for crack length over the number of cycles are derived. Research limitations/implications In this paper, linear fracture mechanics approach is assumed. Practical implications Shortening of evaluation time for fatigue crack growth. Simplification of the computer codes due to the elimination of solution of differential equation. Standardization of experiments for crack growth. Originality/value This paper introduces the closed-form analytical expression for crack length over number of cycles. The new function that expresses the damage growth per cycle is also introduced. This function allows closed-form analytical solution for crack length. The solution expresses the number of cycles to failure as the function of the initial size of the crack and eliminates the solution of the nonlinear ordinary differential equation of the first order. The different common expressions, which account for the influence of the stress ratio, are immediately applicable.

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