scholarly journals Calculation of rear brake power and rear brake work during skidding on paved and gravel cycling surfaces

2019 ◽  
Vol 8 (3) ◽  
pp. 33-38
Author(s):  
Matthew Curtis Miller ◽  
Aden Tully ◽  
Adam Miller ◽  
Stephen R Stannard ◽  
Philip W Fink
Keyword(s):  
Angular Velocity ◽  
Positive Relationship ◽  
Rolling Resistance ◽  
Rear Wheel ◽  
Front Wheel ◽  
Power Meter ◽  
Brake Power ◽  
Strong Positive Relationship ◽  
Bicycle Rider ◽  
Error Of Measurement

The use of a brake power meter at each wheel of a bicycle is a valid means to calculate energy losses due to braking. However, methodology utilizing the torque and angular velocity at each wheel independently are not able to reflect energy lost to braking when the rear wheel is skidding. This study tested the possibility of using the angular velocity of the front wheel, but the torque of the rear brake, to calculate rear brake power. Two cyclists completed 100 braking trials across three days on a mixture of paved and gravel surfaces with a mixture of skidding and non-skidding. The estimated total energy removed from the bicycle-rider system was calculated as the sum of brake work and estimates of drag and rolling resistance. This energy removed from the bicycle-rider system displayed a strong positive relationship with the change in kinetic energy of the bicycle-rider system during braking on paved (r2=0.955; p<0.0001) and gravel surfaces paved (r2=0.702; p<0.0001). There was no difference between these measurements overall (p<0.05), however there is some error of measurement when skidding on gravel. The findings in the present investigation indicate that rear brake work is underestimated when using the angular velocity at the rear wheel during skidding, but that utilising the angular velocity of the front wheel is a valid means of calculating rear brake power. Care should be taken when skidding on gravel as it is difficult to assess the linear velocity of the bicycle.

Closed-form solutions for vehicle traction problems

2002 ◽  
Vol 216 (12) ◽  
pp. 957-963
Author(s):  
J Lieh
Keyword(s):  
Closed Form ◽  
Rolling Resistance ◽  
Rear Wheel ◽  
Front Wheel ◽  
Complex Model ◽  
Inertia Force ◽  
Design Phase ◽  
Closed Form Solutions ◽  
Wheel Drive ◽  
Linear Differential

Conventional approaches to vehicle traction and propulsion analysis have used spread-sheets or numerical integrations owing to the difficulty in deriving closed-form solutions. This is inconvenient if a parameter is to be varied, and it is even more difficult when multiple parameters of a complex model are evaluated at the design phase. In this paper, it is intended to formulate two non-linear differential equations representing road load and power consumption. By expanding inertia force, air drag, rolling resistance, gravitational force and tyre tractive force, the equations can be simplified as functions of velocity v, i.e. s 1 v = s 2-s 3 v2 and m v = (-r 1 v3 - r 2 v + r 3)/v respectively. With these two equations, engineers can use either numerical or analytical methods to study key parameters at the design phase. To demonstrate the effectiveness of these equations, Wright State's electric car model is used. The results for front-wheel drive, rear-wheel drive and four-wheel drive cases are presented.

Analytical Traction and Propulsion Analysis

2001 ◽  
Author(s):  
Junghsen Lieh
Keyword(s):  
Nonlinear Differential Equations ◽  
Rolling Resistance ◽  
Rear Wheel ◽  
Front Wheel ◽  
Inertia Force ◽  
Design Phase ◽  
Multiple Parameters ◽  
Electric Car ◽  
Wheel Drive ◽  
Four Wheel Drive

Abstract Conventional approach for vehicle traction and propulsion analysis used spreadsheets. This is inconvenient if one intends to vary a parameter, and it is even more difficult when multiple parameters are evaluated at the design phase. In this paper, it is intended to formulate two nonlinear differential equations representing road load and power consumption. By expanding inertia force, air drag, rolling resistance, gravitational force and tire tractive force, the equations can be simplified as the function of velocity v, i.e., s 1 v ˙ = s 2 - s 3 v 2 and m v ˙ = - r 1 v 3 - r 2 v + r 3 v , respectively. With these two equations, it allows engineers to use either numerical or analytical method to study key parameters at the design phase. To demonstrate the effectiveness of these equations, Wright State’s electric car model is used. The results for front-wheel drive (FWD), rear-wheel drive (RWD) and four-wheel drive (4WD) cases are presented.

scholarly journals The Effect of Tractor Driving System Type on its Slip and Rolling Resistance and its Modelling Using Anfis

2019 ◽  
Vol 22 (4) ◽  
pp. 115-121
Author(s):  
Abdolmajid Moinar ◽  
Gholamhossein Shahgholi
Keyword(s):  
Fuzzy Inference ◽  
Rolling Resistance ◽  
Soil Surface ◽  
Rear Wheel ◽  
Front Wheel ◽  
Inference System ◽  
Driving System ◽  
Wheel Drive ◽  
Pulling Forces ◽  
Pulling Force

Abstract Pulling force required for operations such as tillage is a result of the interaction between the tractor’s wheel drive and soil surface limited by various factors, such as the rolling resistance and slip of the wheel drive. In this research, the traction performance of tractors with different driving systems (four-wheel drive, rear wheel drive, and front wheel drive) was investigated. Test parameters included different tractor forward speeds (1.26, 3.96, and 6.78 km·h−1), tire inflation pressures (170, 200, and 230 kPa), ballast weights (0, 150, and 300 kg), and aforementioned driving systems, as well as required drafts (2, 6, and 10 kN). For each experiment, two indices of slip and rolling resistance were measured. The results of this study showed that the four-wheel-driving system indicated a low slip at similar pulling forces. In order to achieve a low slip, the four-wheel driving system did not necessarily need to add the ballast weight or to reduce the inflation pressure. The four-wheel driving system showed lower rolling resistance than the other two systems. Slip and rolling resistance of wheels were predicted using an adaptive neuro-fuzzy inference system (ANFIS). It was found that ANFIS had a high potential for predicting the slip (R2 = 0.997) and rolling resistance (R2 = 0.9893).

Effects of Financial Innovations on Profitability for Deposit Taking Microfinancing Institutions in Kenya

2018 ◽  
Vol 9 (6) ◽  
pp. 529-536
Author(s):  
Martin Khoya Odipo ◽  
Keyword(s):  
Financial Institutions ◽  
Positive Relationship ◽  
Financial Institution ◽  
Secondary Data ◽  
Financial Statements ◽  
Descriptive Statistics ◽  
Primary Data ◽  
Microfinance Institutions ◽  
Financial Innovations ◽  
Strong Positive Relationship

Recent studies have documented that innovations improve profitability of firms. This article documents that deposit taking micro financial institutions that have adopted financial innovations have increased their profitability. The study covered five years between 2009-2013. Both primary and secondary data were used in the study. Primary data was obtained through administration of drop and pick questionnaires to selected employees of the institutions. Secondary data was obtained from financial statements and management reports of these deposit taking microfinance institutions. Data was analyzed using descriptive statistics, return on asset and multi-liner regression model to determine the effect of each financial innovation applied on profitability on the micro-financial institution. The results showed that most deposit taking microfinance institutions adopted these financial innovations in their current operations. There was strong positive relationship between individual innovations and profitability. In line with profitability ROA also showed improvement each year after the adoption of these financial innovations.

INTERCONNECTION OF SUSTAINABLE DEVELOPMENT COMPONENTS FOR THE INDIGENOUS PEOPLES OF THE NORTH

2020 ◽  
Vol 2 (8) ◽  
pp. 101-110
Author(s):  
N. N. ILYSHEVA ◽  
◽  
E. V. KARANINA ◽  
G. P. LEDKOV ◽  
E. V. BALDESKU ◽  
...  
Keyword(s):  
Climate Change ◽  
Sustainable Development ◽  
Economic Development ◽  
Indigenous Peoples ◽  
Ecological Footprint ◽  
Positive Relationship ◽  
The North ◽  
Strong Positive Relationship ◽  
The Face ◽  
The Relationship

The article deals with the problem of achieving sustainable development. The purpose of this study is to reveal the relationship between the components of sustainable development, taking into account the involvement of indigenous peoples in nature conservation. Climate change makes achieving sustainable development more difficult. Indigenous peoples are the first to feel the effects of climate change and play an important role in the environmental monitoring of their places of residence. The natural environment is the basis of life for indigenous peoples, and biological resources are the main source of food security. In the future, the importance of bioresources will increase, which is why economic development cannot be considered independently. It is assumed that the components of resilience are interrelated and influence each other. To identify this relationship, a model for the correlation of sustainable development components was developed. The model is based on the methods of correlation analysis and allows to determine the tightness of the relationship between economic development and its ecological footprint in the face of climate change. The correlation model was tested on the statistical materials of state reports on the environmental situation in the Khanty-Mansiysk Autonomous Okrug – Yugra. The approbation revealed a strong positive relationship between two components of sustainable development of the region: economy and ecology.

Are leaders with postgraduate degrees perceived to be more transformational? A quasi-experimental field study

2019 ◽  
Vol 40 (2) ◽  
pp. 259-273 ◽  
Author(s):  
Morris Mendelson ◽  
Jasmine Alam ◽  
Chris Cunningham ◽  
Adam Totton ◽  
Carrie Smith
Keyword(s):  
Transformational Leadership ◽  
Field Study ◽  
Positive Relationship ◽  
Master's Degree ◽  
Leadership Qualities ◽  
Content Type ◽  
Experimental Field ◽  
Strong Positive Relationship ◽  
Quasi Experimental ◽  
Master’S Degree

PurposeTransformational leadership has been shown to have a positive impact on a host of employee level and organizational performance indicators. However, little research has sought to understand some of the antecedents of this style of leadership. The purpose of this paper is to examine the link between having a post-secondary education and perceptions of transformational leadership.Design/methodology/approachData were collected from two surveys issued in a mid-sized energy company located on the eastern seaboard of North America. One-way ANOVA comparing employees’ perceptions of transformational leadership exhibited by their supervisors that either did or did not have a post-graduate degree demonstrated a strong, positive relationship between the attainment of a Master’s degree and perceived levels of transformational leadership qualities.FindingsThe findings of this quasi-experimental field study demonstrated a strong, positive relationship between the attainment of a Master’s degree and perceived levels of transformational leadership qualities.Originality/valueThis study is the first of its kind to demonstrate that more educated managers are generally perceived to be more transformational in their leadership style.

Feedback control framework for car-like robots using the unicycle controllers

Robotica ◽  
2011 ◽  
Vol 30 (4) ◽  
pp. 517-535 ◽  
Author(s):  
Maciej Michałek ◽  
Krzysztof Kozłowski
Keyword(s):  
Stability Analysis ◽  
Feedback Control ◽  
Closed Loop ◽  
Path Following ◽  
Rear Wheel ◽  
Front Wheel ◽  
Steering Angle ◽  
Formal Stability ◽  
Control Framework ◽  
Error Dynamics

SUMMARYThe paper introduces a novel general feedback control framework, which allows applying the motion controllers originally dedicated for the unicycle model to the motion task realization for the car-like kinematics. The concept is formulated for two practically meaningful motorizations: with a front-wheel driven and with a rear-wheel driven. All the three possible steering angle domains for car-like robots—limited and unlimited ones—are treated. Description of the method is complemented by the formal stability analysis of the closed-loop error dynamics. The effectiveness of the method and its limitations have been illustrated by numerous simulations conducted for the three main control tasks, namely, for trajectory tracking, path following, and set-point regulation.

Career Plateau and Turnover Intention in Chinese Employees: Career Anchor as Moderator

2015 ◽  
Vol 43 (5) ◽  
pp. 757-766 ◽  
Author(s):  
Yueran Wen ◽  
Liu Liu
Keyword(s):  
Turnover Intention ◽  
Positive Relationship ◽  
Management Practices ◽  
Career Anchor ◽  
Career Plateau ◽  
Strong Positive Relationship ◽  
High Level ◽  
The Relationship ◽  
Moderating Role

Based on a survey of 147 Chinese employees, we examined the relationship between perceived career plateau and turnover intention, and the moderating role of career anchor in challenge in this process. We hypothesized that perceived career plateau would be positively related to turnover intention, and that this relationship would be stronger in employees with a higher level of career anchor in challenge than in those with a lower level. The results showed that perceived career plateau had a strong positive relationship with turnover intention, especially in employees with a high level of career anchor in challenge. These findings have implications for research in career development and turnover intention, as well as in management practices.

Hubungan Budaya Pengamanan dan Kinerja Bandar Udara dengan Kepuasan Penumpang Angkutan Udara di Bandar Udara Internasional Soekarno - Hatta

WARTA ARDHIA ◽  
2013 ◽  
Vol 39 (2) ◽  
pp. 128-145
Author(s):  
Siti Masrifah
Keyword(s):  
Significant Relationship ◽  
Positive Relationship ◽  
Service Performance ◽  
Air Transport ◽  
Cultural Relations ◽  
Security Culture ◽  
International Airport ◽  
Passenger Satisfaction ◽  
Strong Positive Relationship ◽  
And Performance

This study examined the association of security culture (X1) and the performance of airport services (X2) with air transport passenger satisfaction (Y), either individually or jointly.This study with a sample of 100 respondents passenger air transport, the distribution of questionnaires to terminal 2F domestic at Soekarno Hatta International Airport Cengkareng.Calculation results show a positive and significant relationship shown in securing cultural relations (X1) to the satisfaction of passenger air transport (Y). Airport service performance (X2) to the satisfaction of passenger air transport (Y). The relation security culture and performance of airport service to the satisfaction of the air transport of passengers together.The final results of this study have a strong positive relationship between security culture in air transport passenger satisfaction. Strong positive relationship between performance of airport services in air transport passenger satisfaction. And a strong positive relationship between culture security and performance of airport services to the satisfaction of the air transport of passengers together.Penelitian ini untuk mengetahui hubungan budaya pengamanan (X1) dan kinerja pelayanan bandar udara (X2) dengan kepuasan penumpang angkutan udara (Y), baik secara sendiri-sendiri maupun secara bersama-sama. Penelitian ini dengan jumlah sampel sebanyak 100 responden penumpang angkutan udara, dengan melakukan sebaran kuesioner di terminal 2F domestik Bandar Udara International Soekarno Hatta Cengkareng. Hasil perhitungan menunjukkan hubungan yang positif dan signifikan pada budaya pengamanan (X1) dengan kepuasan penumpang angkutan, hubungan positif dan signifikan antara kinerja pelayanan bandar udara (X2) dengan kepuasan penumpang angkutan udara (Y), serta menghasilkan hubungan positif dan signifikan antara budaya pengamanan (X1) dan kinerja pelayanan Bandar udara (X2) dengan kepuasan penumpang angkutan udara (Y) secara bersama-sama. Hasil akhir penelitian ini mempunyai hubungan positif dan kuat antara budaya pengamanan dengan kepuasan penumpang angkutan udara. Hubungan positif dan kuat antara kinerja pelayanan Bandar udara dengan kepuasan penumpang angkutan udara. Hubungan positif dan kuat antara budaya pengamanan dan kinerja pelayanan Bandar udara dengan kepuasan penumpang angkutan udara secara bersama-sama. Implikasi bagi penyelenggara bandar udara dalam tercapainya kepuasan penumpang angkutan udara dengan memberikan rasa aman, lancar, tertib, dan selamat dalam suatu penerbangan, serta jasa pelayanan bandar udara dengan kebersihan terminal dan ketersediaan fasilitas yang cukup dan baik.

scholarly journals Sustainability and Competitiveness of Thailand’s Natural Rubber Industry in Times of Global Economic Flux

2017 ◽  
Vol 14 (1) ◽  
pp. 169
Author(s):  
Palapan Kampan
Keyword(s):  
Natural Rubber ◽  
Positive Relationship ◽  
New Technologies ◽  
Pearson Correlation ◽  
The United States ◽  
Bivariate Correlation ◽  
Synthetic Rubber ◽  
Reinforcing Factors ◽  
Strong Positive Relationship ◽  
Correlation Tests

This study assesses economic, legal, and environmental conditions that Thai rubber farmers face, and evaluates actions they can take to increase incomes. Statistical analyses determine relationships between prices of oil, natural and synthetic rubber. Pearson correlation tests found a strong positive relationship (r = 0.887) between the price of Brent crude and Thai ribbed smoked sheets, and a moderate positive relationship between price changes in Brent and synthetic rubber (r = 0.648). Regression analysis showed Brent oil price is a good predictor of natural rubber prices. Moderate to strong positive relationships were also found between natural rubber price and gross domestic product of Japan, China, and the United States. Criminal antitrust behavior in rubber industries appeared to interfere with normal pricing in rubber markets. No significant bivariate correlation was found between rainfall in Thailand and natural rubber price, production, or export although flooding and other environmental issues clearly affected rubber farms. A survey of options showed Thai rubber farmers can improve livelihoods best through collective purchase and use of new technologies, and by integrating into downstream supply chain industries. At very least, farmers are urged to abandon monocrop methods and supplement incomes with fruit, fish, livestock, or pigs. stment budget, 2) architectural Aesthetic, and 3) utilization. Additionally, background of the interviewees is one of reinforcing factors for decision on universal design investment.

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