A novel retractable landing gear of a light amphibious airplane design, synthesis, analysis, and implementation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sinchai Chinvorarat ◽  
Pumyos Vallikul
Keyword(s):  
Impact Load ◽  
Landing Gear ◽  
Drop Test ◽  
Drop Height ◽  
Core Element ◽  
Design Synthesis ◽  
Content Type ◽  
And Performance ◽  
Correct Path ◽  
The Impact

Purpose The purpose of this paper is to present a novel retractable main landing gear for a light amphibious airplane, while the design, synthesis and analysis are given in details for constructing the main landing gear. Design/methodology/approach The constraint three-position synthesis has given the correct path of all linkages that suitably fit the landing gear into the compartment. The additional lock-link is introduced into the design to ensure the securement of the mechanism while landing. Having the telescopic gas-oil shock strut as a core element to absorb the impact load, it enhances the ability and efficiency to withstand higher impact than others type of light amphibious airplane. Findings By kinematics bifurcation analysis, the optimized value of the unlock spring stiffness at 90 N/m can be found to tremendously reduce the extended-retracted linear actuator force from 500 N to 150 N at the beginning of the retraction sequence. This could limit the size and weight of the landing gear actuator of the light amphibious airplane. Practical implications The drop test of the landing gear to comply with the ASTM f-2245 (Standard Specification for Design and Performance of a Light Sport Airplane) reveals that the novel landing gear can withstand the impact load at the drop height determined by the standard. The maximum impact loading 4.8 G occurs at the drop height of 300 mm, and there is no sign of any detrimental or failure of the landing gear or the structure of the light amphibious airplane. The impact settling time response reaches the 2% of steady-state value in approximately 1.2 s that ensure the safety and stability of the amphibious airplane if it subjects to an accidentally hard landing. Originality/value This paper presents unique applications of a retractable main landing gear of a light amphibious airplane. The proposed landing gear functions properly and complies with the drop test standard, ensuring the safety and reliability of the airplane and exploiting the airworthiness certification process.

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

Increasing revenue and attendance in Canadian Baptist churches

2015 ◽  
Vol 42 (12) ◽  
pp. 1071-1089
Author(s):  
Alan Chan ◽  
Bruce G. Fawcett ◽  
Shu-Kam Lee
Keyword(s):  
Church Health ◽  
Eastern Canada ◽  
Data Set ◽  
Content Type ◽  
Factors Affecting ◽  
Scarce Resources ◽  
Baptist Churches ◽  
And Performance ◽  
The Impact ◽  
Simulation Exercises

Purpose – Church giving and attendance are two important indicators of church health and performance. In the literature, they are usually understood to be simultaneously determined. The purpose of this paper is to estimate if there a sustainable church congregation size using Wintrobe’s (1998) dictatorship model. The authors want to examine the impact of youth and adult ministry as well. Design/methodology/approach – Using the data collected from among Canadian Baptist churches in Eastern Canada, this study investigates the factors affecting the level of the two indicators by the panel-instrumental variable technique. Applying Wintrobe’s (1998) political economy model on dictatorship, the equilibrium level of worship attendance and giving is predicted. Findings – Through various simulation exercises, the actual church congregation sizes is approximately 50 percent of the predicted value, implying inefficiency and misallocation of church resources. The paper concludes with insights on effective ways church leaders can allocate scarce resources to promote growth within churches. Originality/value – The authors are the only researchers getting the permission from the Atlantic Canada Baptist Convention to use their mega data set on church giving and congregation sizes as per the authors’ knowledge. The authors are also applying a theoretical model on dictatorship to religious/not for profits organizations.

Performance measurement and resource sharing among business sub-units in the presence of non-discretionary factors

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rita Shakouri ◽  
Maziar Salahi
Keyword(s):  
Resource Sharing ◽  
Content Type ◽  
Development Level ◽  
Proposed Model ◽  
Decision Making Unit ◽  
Efficiency Estimation ◽  
Overall Efficiency ◽  
And Performance ◽  
The Right ◽  
The Impact

Purpose This paper aims to apply a new approach for resource sharing and efficiency estimation of subunits in the presence of non-discretionary factors and partial impacts among inputs and outputs in the data envelopment analysis (DEA) framework. Design/methodology/approach First, inspired by the Imanirad et al.’s model (2013), the authors consider that each decision-making unit (DMU) may consist of several subunits, that each of which can be affected by non-discretionary inputs. After that, the Banker and Morey’s model (1996) is used for modeling non-discretionary factors. For measuring performance of several subunits, which can be considered as DMUs, the aggregate efficiency is suggested. At last, the overall efficiency is computed and compared with each other. Findings One of the important features of proposed model is that each output in this model applies discretionary input according to its need; therefore, the result of this study will make it easier for the managers to make better decisions. Also, it indicates that significant predictions of the development of the overall efficiency of DMUs can be based on observing the development level of subunits because of the influence of non-discretionary input. Therefore, the proposed model provides a more reasonable and encompassing measure of performance in participating non-discretionary and discretionary inputs to better efficiency. An application of the proposed model for gaining efficiency of 17 road patrols is provided. Research limitations/implications More non-discretionary and discretionary inputs can be taken into consideration for a better analysis. This study provides us with a framework for performance measures along with useful managerial insights. Focusing upon the right scope of operations may help out the management in improving their overall efficiency and performance. In the recent highway maintenance management systems, the environmental differences exist among patrols and other geotechnical services under the climate diverse. Further, in some cases, there might exist more than one non-discretionary factor that can have different effects on the subunits’ performance. Practical implications The purpose of this paper was to measure the performance of a set of the roadway maintenance crews and to analyze the impact of non-discretionary inputs on the efficiency of the roadway maintenance. The application of the proposed model, on the one hand, showed that each output in this model uses discretionary input according to its requirement, and on the other hand, the result showed that meaningful predictions of the development of the overall efficiency of DMUs can be based on observing the development level of subunits because of the impact of non-discretionary input. Originality/value Providing information on resource sharing by taking into account non-discretionary factors for each subunit can help managers to make better decisions to increase the efficiency.

Impact of COVID-19 pandemic on indigenous contractors in a developing economy

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nathaniel Ayinde Olatunde ◽  
Imoleayo Abraham Awodele ◽  
Bosede Olajumoke Adebayo
Keyword(s):  
Developing Economies ◽  
Sampling Technique ◽  
Structured Interview ◽  
Additional Cost ◽  
Developing Economy ◽  
Content Type ◽  
Construction Contracts ◽  
The Government ◽  
And Performance ◽  
The Impact

Purpose The purpose of this study is to examine the impact of coronavirus disease 2019 (COVID-19) on indigenous contractors in a developing economy with a view to enhancing their performance. Design/methodology/approach The study used a purposive sampling technique to select 37 indigenous contractors with ongoing construction contracts in Osun State, Nigeria who provided data for the study. A structured interview protocol was used to elicit the required information from the interviewees and frequency, percentage and content analysis were used for data analysis. Findings The results showed that the critical impact of COVID-19 on indigenous contractors in a developing economy is: time overrun, loss of profit and creation of dispute. Further results showed that other impacts are a disruption in supply of labour, locally sourced materials are with additional cost, the additional cost of implementing COVID-19 protocols, difficulty in sourcing imported materials and absence of new jobs with the corresponding retrenchment of workers. Practical implications The study recommended special palliatives for the indigenous contractors from the government so as to cushion the impact of the pandemic on them, thereby enhance their survival and performance. A special arbitration panel is set up in each state of the federation to look at disputes arising from the aftermath of the pandemic, this is with a view to adequately compensate indigenous contractors with genuine and properly compiled claims. inferring from the findings of the study, it suffices to say that the severity of the impact of the pandemic is very high on indigenous contractors in developing economies, as such a better preparedness strategy could lessen the impact of such pandemic in the future. Originality/value The study is an attempt to unearth the impact of COVID-19 on indigenous contractors with ongoing construction contracts in a developing economy. The study will be of value to construction stakeholders in providing the information needed to devise strategies to minimise the impact of a pandemic on indigenous contractors in future projects thereby enhance their performance.

Exploring the impact of intellectual capital on company reputation and performance

2018 ◽  
Vol 19 (5) ◽  
pp. 915-934 ◽  
Author(s):  
Gianluca Ginesti ◽  
Adele Caldarelli ◽  
Annamaria Zampella
Keyword(s):  
Human Capital ◽  
Intellectual Capital ◽  
Corporate Reputation ◽  
Intangible Asset ◽  
Competition Authority ◽  
Data Set ◽  
Content Type ◽  
Capital Efficiency ◽  
And Performance ◽  
The Impact

Purpose The purpose of this paper is to analyse the impact of intellectual capital (IC) on the reputation and performance of Italian companies. Design/methodology/approach The paper exploits a unique data set of 452 non-listed companies that obtained a reputational assessment from the Italian Competition Authority (ICA). To test the hypotheses, this study implemented several regression analyses. Findings Results support the argument that human capital efficiency is a key driver of corporate reputation. Findings also reveal that companies, which obtained reputational rating under ICA scrutiny, show a positive relationship between IC elements and various measures of financial performance. Research limitations/implications The study focuses on a single country; it is not free from the imprecisions of Pulic’s VAIC model. Practical implications This paper recommends companies that are interested to achieve a robust reputation should consider the human capital as a strategic intangible asset. Second, the results suggest that companies with an ICA reputational rating are able to leverage their intangibles to potentiate performance and competitiveness. Originality/value This is the first empirical investigation on the contribution of IC in generating value for corporate reputation. Additionally, the study contributes to the literature on the link between IC and performance by examining a sample of firms not yet explored in prior research.

The effect of body-movement teaching, learning motivation and performance

2016 ◽  
Vol 24 (3) ◽  
pp. 414-437 ◽  
Author(s):  
Satoshi Sugahara ◽  
Hisayo Sugao ◽  
Steven Dellaportas ◽  
Takahiro Masaoka
Keyword(s):  
Body Movement ◽  
Learning Motivation ◽  
Control Group ◽  
Content Type ◽  
Entry Level ◽  
Quasi Experimental ◽  
And Performance ◽  
Teaching Learning ◽  
The Impact ◽  
Experimental Group

Purpose This research applies a quasi-experimental research method to investigate the impact of an innovative resource titled “Accounting Exercise” (teaching intervention using physical movement and lyrics) on learning motivation and performance on a group of students enrolled in a first-year undergraduate accounting course in Japan. Design/methodology/approach Five classes were randomly assigned to either an experimental group (two classes) or a control group (three classes). In the experimental group, 90 students participated in a 15-min “Accounting Exercise” at the commencement of lectures over three consecutive weeks. The remaining 133 students assigned to the control group did not participate in the Accounting Exercise. Findings The findings indicate that the Accounting Exercise provided stimuli in maintaining students’ learning motivation. This finding is important for entry-level students where learning motivation has the potential to influence students’ future decisions on major areas of study and career choices. Originality/value This finding is important for entry-level students where future career options are decided. This effect is also believed to contribute to reducing the declining numbers of students in accounting majors.

Effects of Wall Thickness and Crush Initiators Position under Experimental Drop Test on Square Tubes

2017 ◽  
Vol 865 ◽  
pp. 612-618 ◽  
Author(s):  
M. Malawat ◽  
Jos Istiyanto ◽  
D.A. Sumarsono
Keyword(s):  
Energy Absorption ◽  
Tube Wall ◽  
Impact Load ◽  
Peak Load ◽  
Load Force ◽  
Drop Height ◽  
Thin Walled ◽  
The Impact ◽  
Initial Peak ◽  
Load Mass

Crush initiators are the weakest points to reduce initial peak load force with significant energy absorption ability. The objective of this paper is to study the effects of square tube thickness and crush initiators position for impact energy absorber (IEA) performance on thin-walled square tubes. Two square tubes having thickness about 0.6 mm (specimen code A) and 1 mm (specimen Code C) were tested under dynamic load. The crushing initiator is designed around the shape of the tube wall and has eight holes with a fixed diameter of 6.5 mm. In the experiment, the crushing initiator was determined at 5 different locations on the specimen wall. These locations are 10 mm, 20 mm. 30 mm, 40 mm, and 50 mm measured from the initial collision position of the specimen tested. The impact load mass was about 80 kg and had a drop height of about 1.5 m. Using the simulation program of the LabVIEW Professional Development System 2011 and National Instrument (NI) 9234 software equipped with data acquisition hardware NI cDAQ-9174 the signal from the load cell was sent to a computer. By controlling the thickness of the thin-walled square tube, the peak loading force can be decreased by approximately 56.75% and energy absorption ability of IEA can be increased approximately to 11.83%. By using different thin-walled square tube can produce different best crush initiators position with the lowest peak load force.

Knowledge management, workplace climate, creativity and performance

2018 ◽  
Vol 30 (8) ◽  
pp. 592-612 ◽  
Author(s):  
Amro Alzghoul ◽  
Hamzah Elrehail ◽  
Okechukwu Lawrence Emeagwali ◽  
Mohammad K. AlShboul
Keyword(s):  
Job Performance ◽  
Knowledge Sharing ◽  
Authentic Leadership ◽  
Equation Modeling ◽  
Workplace Climate ◽  
Content Type ◽  
And Performance ◽  
The Impact ◽  
The Relationship

Purpose This study aims at providing empirical evidence pertaining to the interaction among authentic leadership, workplace harmony, worker's creativity and performance in the context of telecommunication sector. These research streams remain important issues and of interest as the world continues to migrate toward a knowledge-based economy. Design/methodology/approach Applying structural equation modeling, this study diagnosed the impact of Authentic leadership (AL) on employees (n = 345) in two Jordanian telecommunication firms, specifically, how it shapes workplace climate, creativity and job performance. The study also tests the moderating role of knowledge sharing in the model, as well as the mediating role of workplace climate on the relationship between AL and positive organizational outcomes. Findings The empirical result suggests that AL positively influences workplace climate, creativity and job performance; workplace climate positively influences creativity and job performance; workplace climate mediates the relationship between AL and creativity, and job performance; and knowledge sharing behavior moderates the relationship between AL and workplace climate. Originality/value This study highlights the magnificent power of AL and knowledge sharing, not only in shaping the workplace atmosphere but also in delineating how these variables stimulate creativity and performance among employees. The implications for research and practice are discussed.

scholarly journals Competition, performance and financial stability in US agricultural banking

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Madhav Regmi ◽  
Allen M. Featherstone
Keyword(s):  
Market Power ◽  
Financial Stability ◽  
Relationship Lending ◽  
Net Income ◽  
Bank Competition ◽  
Content Type ◽  
Linear Effect ◽  
And Performance ◽  
The Impact ◽  
Agricultural Banking

PurposeThe number of US commercial banks has declined by about 50% over the last two decades. This change could lead to a potential decline in competition and a potential increase in market power in the agricultural banking market. The focus of this study is to examine whether the risk of failure and the performance of agricultural banks has been affected by bank consolidations.Design/methodology/approachThe impact of bank competition on performance and financial stability of agricultural banks is studied using a Lerner index as a measure of market power. A Z-score is constructed to measure bank stability. Similarly, the return on assets (net income to total assets ratio), return on equity (net income to the total equity ratio), agricultural loan ratio and agricultural loan volume are used as performance measures for agricultural banks. Two-way fixed effect regression models are estimated to measure the impact of competition on financial stability and performance.FindingsResults indicate that bank competition has a U-shaped effect on the probability of default and an inverted U-shaped effect on volume and proportion of agricultural lending. There also exists evidence of a positive but non-linear effect of bank market power on the profitability of agricultural banks.Originality/valueThere is limited literature on the impact of bank competition on financial stability and performance of US agricultural banks. Agricultural banks hold more than 40% of US farm debt. A decrease in the number of banks or the level of competition in agricultural banking may cause an adverse effect on relationship lending. The key findings imply that bank regulatory strategies should focus on enhancing (reducing) competition in more (less) concentrated banking markets to improve the financial health and performance of agricultural banks.

Financial disclosure and performance of microfinance institutions

2014 ◽  
Vol 10 (3) ◽  
pp. 314-337 ◽  
Author(s):  
Shakil Quayes ◽  
Tanweer Hasan
Keyword(s):  
Financial Performance ◽  
Least Squares ◽  
Least Squares Method ◽  
Financial Disclosure ◽  
Microfinance Institutions ◽  
Content Type ◽  
Three Stage Least Squares ◽  
And Performance ◽  
The Impact ◽  
The Relationship

Purpose – The purpose of this paper is to analyze the relationship between financial disclosure and the financial performance of microfinance institutions (MFIs). Design/methodology/approach – The paper utilizes ordinary least squares method to analyze the impact of disclosure on financial performance, an ordered probit model to investigate the possible effect of financial performance on disclosure and utilizes a three-stage least squares method to delineate the endogenous relationship between disclosure and financial performance of MFIs. Findings – The paper finds that better disclosure has a statistically significant positive impact on operational performance of MFIs; second, it also shows that improved financial performance results in better financial disclosure. Keeping the endogenous nature of the relationship between disclosure and performance, the paper uses a three-stage least squares method to show that disclosure and financial performance positively affect each other simultaneously. Research limitations/implications – The paper attempts to delineate a positive association between better disclosure on financial performance of MFIs, which can be used for developing a better disclosure policy by management, formulating more effective guidelines for disclosure by the stakeholders and mandating more appropriate laws and uniform disclosure practice by regulators. Originality/value – This is the first study that uses a large number of MFIs from 75 countries; second, it uses a uniform scale of designating a disclosure rating (assigned by MIX Market) to show the relationship between disclosure and performance. Finally, it uses three-stage least squares method to address the possible endogeneity between disclosure and performance.

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