Influence of Altitude on the Performance of a Bicycle-Cyclist Set

Author(s):  
Mateo Morales ◽  
Sergio D. Roa ◽  
Luis E. Muñoz ◽  
Diego A. Ferreira ◽  
Omar D. Lopez Mejia

There is a tradeoff between power delivery and aerodynamic drag force when cyclists ride at different altitudes. The result is particular to the characteristics of the bicycle as well as the aerobic fitness of the cyclist. This work proposes a methodology based on an integrated approach to the study of the influence of altitude on power output and aerodynamic drag over a particular bicycle-cyclist set. The methodology consists of an independent analysis for each of the effects, to conclude with an integration of results that allows estimating the overall effect of altitude on cycling performance. A case study for the application of the methodology was developed, and the obtained results apply for the specific bicycle-cyclist set under analysis. First, the relationship between power and time was analyzed for a male recreational cyclist based on all-out effort tests at two different altitudes: 237 meters and 2652 meters above sea level (m.a.s.l). Second, the effects of environmental conditions on air density and drag area coefficient due to altitude changes were analyzed based on Computational Fluid Dynamics (CFD) simulations. It was found that for the bicycle-cyclist set under study, the sustainable power output for 1-hour cycling was reduced 45W for the high-altitude condition as a consequence of the reduction in the maximum oxygen uptake capacity. In addition, the aerodynamic drag force is reduced in greater proportion due to the change in air density than due to the change in drag coefficient. Finally, the results of both effects were integrated to analyze the overall influence of altitude on cycling performance. It was found that for the analyzed case study, the aerodynamic advantage at higher altitude dominates over the disadvantage of reduction in power output: despite delivering 45W less, the subject can travel an additional distance of 900 meters during a one hour ride for the high-altitude condition compared to that in low altitude.

Author(s):  
Alejandra Polanco ◽  
Juan Fuentes ◽  
Sebastián Porras ◽  
Daniel Castiblanco ◽  
Julián Uribe ◽  
...  

Abstract The aerodynamic drag force has a relevant effect on cycling performance since it is one of the major resistive forces acting on the bicycle. For this reason, this paper presents the development of an experimental methodology to estimate the aerodynamic parameters of a bicycle-cyclist set. The methodology combines outdoor measurements to estimate the drag area with indoor measurements to measure the projected frontal area. The methodology was implemented to quantify the effect of posture in the aerodynamic parameters of a group of cyclists. The tests were performed to characterize the drag parameters associated with three postures defined by the position of the grip on the handlebar: tops, hoods, and drops. Significant differences in the aerodynamic parameters were found for the postures studied through the proposed methodology. The posture variation led to reductions of up to 11.8% in the drag area of the cyclists when passing from tops to drops posture. The results obtained are in agreement with the literature indicating that the implementation of the methodology is feasible for the estimation of the aerodynamic parameters in cycling.


2009 ◽  
Author(s):  
Vincent Wai Tin Kong ◽  
Alexis Carrillat ◽  
John Ross Gaither ◽  
Ahmad Bukhari Ibrahim ◽  
Irmawaty Abdullah ◽  
...  
Keyword(s):  

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 15914-15928
Author(s):  
Ridha Ben Mansour ◽  
Meer Abdul Mateen Khan ◽  
Fahad Abdulaziz Alsulaiman ◽  
Rached Ben Mansour

2021 ◽  
Vol 13 (5) ◽  
pp. 949
Author(s):  
Salman Qureshi ◽  
Saman Nadizadeh Shorabeh ◽  
Najmeh Neysani Samany ◽  
Foad Minaei ◽  
Mehdi Homaee ◽  
...  

Due to irregular and uncontrolled expansion of cities in developing countries, currently operational landfill sites cannot be used in the long-term, as people will be living in proximity to these sites and be exposed to unhygienic circumstances. Hence, this study aims at proposing an integrated approach for determining suitable locations for landfills while considering their physical expansion. The proposed approach utilizes the fuzzy analytical hierarchy process (FAHP) to weigh the sets of identified landfill location criteria. Furthermore, the weighted linear combination (WLC) approach was applied for the elicitation of the proper primary locations. Finally, the support vector machine (SVM) and cellular automation-based Markov chain method were used to predict urban growth. To demonstrate the applicability of the developed approach, it was applied to a case study, namely the city of Mashhad in Iran, where suitable sites for landfills were identified considering the urban growth in different geographical directions for this city by 2048. The proposed approach could be of use for policymakers, urban planners, and other decision-makers to minimize uncertainty arising from long-term resource allocation.


2021 ◽  
Vol 13 (8) ◽  
pp. 4487
Author(s):  
Maghsoud Amiri ◽  
Mohammad Hashemi-Tabatabaei ◽  
Mohammad Ghahremanloo ◽  
Mehdi Keshavarz-Ghorabaee ◽  
Edmundas Kazimieras Zavadskas ◽  
...  

Evaluating the life cycle of buildings is a valuable tool for assessing sustainability and analyzing environmental consequences throughout the construction operations of buildings. In this study, in order to determine the importance of building life cycle evaluation indicators, a new combination method was used based on a quantitative-qualitative method (QQM) and a simplified best-worst method (SBWM). The SBWM method was used because it simplifies BWM calculations and does not require solving complex mathematical models. Reducing the time required to perform calculations and eliminating the need for complicated computer software are among the advantages of the proposed method. The QQM method has also been used due to its ability to evaluate quantitative and qualitative criteria simultaneously. The feasibility and applicability of the SBWM were examined using three numerical examples and a case study, and the results were evaluated. The results of the case study showed that the criteria of the estimated cost, comfort level, and basic floor area were, in order, the most important criteria among the others. The results of the numerical examples and the case study showed that the proposed method had a lower total deviation (TD) compared to the basic BWM. Sensitivity analysis results also confirmed that the proposed approach has a high degree of robustness for ranking and weighting criteria.


Designs ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 31
Author(s):  
Daniel Moran ◽  
Atila Ertas ◽  
Utku Gulbulak

The continued displacement of refugees from their homes and homelands (now greater than 50 million people worldwide) places increased focus and attention on evolving the designs of temporary housing that is available to be provided to the refugee population, especially in rural areas where housing does not already exist and must be constructed in very little time. Complex engineering problems involving social issues, such as this case study, benefit from the use of Integrated Transdisciplinary (TD) Tools (ITDT) to effectively and efficiently address the design questions related to them. The integrated use of TD Tools such as Kano Analysis, KJ Diagrams, Critical to Quality (CTQ), House of Quality (HOQ)/Quality Function Design (QFD), Theory of Inventive Problem Solving (TRIZ), Axiomatic Design (AD), Interpretive Structural Modeling (ISM), and Design Structure Matrix (DSM) through an end-to-end unique design process leads to innovation and elimination of design conflicts for especially complicated design problems. The objective of this study is to examine the design of temporary refugee housing using integrated TD tools mentioned above. This research concludes that the use of the ITDT approach provides an innovative, decoupled design.


2021 ◽  
Vol 11 (2) ◽  
pp. 64
Author(s):  
Christian García-Carrillo ◽  
Ileana María Greca ◽  
María Fernández-Hawrylak

An analysis is presented in this study that provides insight into a practical training process and its impact on teachers and their viewpoints toward the integrated STEM approach used in that training process, together with educational coding and robotics, over the first years of compulsory primary education, where STEM implementations are relatively new. A case study was developed by two teachers following the practical training course, including pre- and post-interviews and nonparticipative observation of their classroom practices during the teacher-training sessions. The results revealed the positive perspectives that the teachers held toward the STEM-integrated approach and educational coding and robotics, despite the difficulties that arose in classroom practice. It was concluded that the STEM approach and its methods were beneficial both to pupils and to teachers alike for improving the teaching–learning process.


2016 ◽  
Vol 371 (1689) ◽  
pp. 20150213 ◽  
Author(s):  
Fabrice Pernet ◽  
Coralie Lupo ◽  
Cédric Bacher ◽  
Richard J. Whittington

Emerging diseases pose a recurrent threat to bivalve aquaculture. Recently, massive mortality events in the Pacific oyster Crassostrea gigas associated with the detection of a microvariant of the ostreid herpesvirus 1 (OsHV-1µVar) have been reported in Europe, Australia and New Zealand. Although the spread of disease is often viewed as a governance failure, we suggest that the development of protective measures for bivalve farming is presently held back by the lack of key scientific knowledge. In this paper, we explore the case for an integrated approach to study the management of bivalve disease, using OsHV-1 as a case study. Reconsidering the key issues by incorporating multidisciplinary science could provide a holistic understanding of OsHV-1 and increase the benefit of research to policymakers.


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