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Full-Text Articles in Engineering

An Experimental Investigation Characterizing The Tribological Performance Of Natural And Synthetic Biolubricants Composed Of Carboxylic Acids For Energy Conservation And Sustainability, Carlton Jonathan Reeves Dec 2013

An Experimental Investigation Characterizing The Tribological Performance Of Natural And Synthetic Biolubricants Composed Of Carboxylic Acids For Energy Conservation And Sustainability, Carlton Jonathan Reeves

Theses and Dissertations

Over the last several decades the lubrication industry has been striving to bring bio-based lubricants known as biolubricants to prominence. The reasons for the increased environmental initiatives are due to depletion of oil reserves, increases in oil price, stringent government regulations on petroleum-based oils, and most importantly, concerns for protecting the environment. With an estimated, 50% of all lubricants entering the environment and much of these being composed of toxic mineral oils, biolubricants have begun to witness a resurgence. This experimental investigation seeks to develop a new class of ecofriendly biolubricants that are less toxic to the environment, derived from …


Modeling The Relaxation Time Of Dna Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman Oct 2013

Modeling The Relaxation Time Of Dna Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman

Faculty Publications

Using a mapping between a Rouse dumbbell model and fine-grained Monte Carlo simulations, we have computed the relaxation time of λ-DNA in a high ionic strength buffer confined in a nanochannel. The relaxation time thus obtained agrees quantitatively with experimental data [Reisner et al., Phys. Rev. Lett. 94, 196101 (2005)] using only a single O(1) fitting parameter to account for the uncertainty in model parameters. In addition to validating our mapping, this agreement supports our previous estimates of the friction coefficient of DNA confined in a nanochannel [Tree et al., Phys. Rev. Lett. 108, 228105 …


Motion And Force Transmission Of A Flexible Instrument Inside A Curved Endoscope, Jitendra P. Khatait Sep 2013

Motion And Force Transmission Of A Flexible Instrument Inside A Curved Endoscope, Jitendra P. Khatait

Jitendra P Khatait

Flexible instruments are increasingly used to perform advanced and complex surgical procedures either manually or robotically. The success of flexible instruments in surgery requires high motion and force fidelity, and controllability of the tip. However, the friction and the limited stiffness of such instruments limit their motion and force transmission. The implementation of flexible instruments in surgery necessitates their characterization, the development of proper tools to understand the effect of various mechanical parameters on their overall performance, and an improvement in motion and force fidelity. Therefore, this thesis describes 2-D and 3-D flexible multibody models of a flexible surgical instrument …


Experimental And Theoretical Investigations Of Lube Oil Performance And Engine Friction, William Fredrick Rohr May 2013

Experimental And Theoretical Investigations Of Lube Oil Performance And Engine Friction, William Fredrick Rohr

Doctoral Dissertations

The feasibility of using a motored small, single-cylinder 517 cc Hatz 1D50 diesel engine to evaluate lube oil performance and engine friction at conditions typical for a fired engine is investigated in the present study. In addition a commercial engine modeling software, AVL Excite Power Unit, is used to predict the effects of lube oil formulations on the engine friction of the same engine. The motored engine can be operated with and without compression and with and without the engine oil pump. Lube oil performance is evaluated for 19 different lube oils by using either instantaneous motoring torque (motoring torque …


Investigation Of Friction And Wear Characteristics Of Palm Biodiesel Mar 2013

Investigation Of Friction And Wear Characteristics Of Palm Biodiesel

A.S. Md Abdul Haseeb

Use of biodiesel in automobile engine is creating tribology related new challenges. The present study aims to assess the friction and wear characteristics of palm biodiesel at different concentration level by using four-ball wear machine. The investigated fuels were biodiesel (B100), diesel (B0) and three different biodiesel blends such as B10 (10% biodiesel in diesel), B20, B50. Tests were conducted at 75 °C under a normal load of 40 kg for 1 h at four different speeds viz, 600, 900, 1200 and 1500 rpm. Worn surfaces of the balls were examined by SEM. Results showed that wear and friction decreased …


Investigation Of Friction And Wear Characteristics Of Palm Biodiesel Jan 2013

Investigation Of Friction And Wear Characteristics Of Palm Biodiesel

A.S. Md Abdul Haseeb

Use of biodiesel in automobile engine is creating tribology related new challenges. The present study aims to assess the friction and wear characteristics of palm biodiesel at different concentration level by using four-ball wear machine. The investigated fuels were biodiesel (B100), diesel (B0) and three different biodiesel blends such as B10 (10% biodiesel in diesel), B20, B50. Tests were conducted at 75 °C under a normal load of 40 kg for 1 h at four different speeds viz, 600, 900, 1200 and 1500 rpm. Worn surfaces of the balls were examined by SEM. Results showed that wear and friction decreased …


A Novel Cost Effective Method For Vehicle Tire-Road Friction Coefficient Estimation, Boyuan Li, Haiping Du, Weihua Li Jan 2013

A Novel Cost Effective Method For Vehicle Tire-Road Friction Coefficient Estimation, Boyuan Li, Haiping Du, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

The tire-road friction coefficient is critical to vehicle longitudinal, lateral and roll dynamics and control because tire is the only contact part between the vehicle body and the road. However, direct measurement of tire-road friction coefficient is impossible in practice. This paper presents a novel cost effective method for vehicle tire-road friction coefficient estimation. This method only needs the measurements of the wheel angular velocity, the traction/brake torque and the longitudinal acceleration, which are all available from the commonly installed sensors in ordinary passenger vehicles, and can be used to estimate the individual tire-road friction coefficient. There are three steps …


Effect Of Particle Properties On The Discrete Element Simulation Of Wall Friction, Andrew Grima, Peter Wypych Jan 2013

Effect Of Particle Properties On The Discrete Element Simulation Of Wall Friction, Andrew Grima, Peter Wypych

Faculty of Engineering and Information Sciences - Papers: Part A

Modelling the interaction between particles and boundaries is of great interest and importance in many Discrete Element Method (DEM) applications where boundary failure conditions dictate the flow behaviour and velocity gradients of a bulk material. Bulk wall friction angles in DEM models are dependent on the mechanical properties of the particles and boundary material as well as the constraints of the contact models used, especially the tangential and rolling torque components. This paper examines the parameters determined from the calibration inclination test by conducting direct wall shear tests to validate the accuracy of the calibration parameters and the sensitivity of …


Some Influences On Wall Friction Measurements - A Preliminary Investigation, Wendy Halford, Cameron Lawler, Andrew P. Grima, Peter C. Arnold Jan 2013

Some Influences On Wall Friction Measurements - A Preliminary Investigation, Wendy Halford, Cameron Lawler, Andrew P. Grima, Peter C. Arnold

Faculty of Engineering and Information Sciences - Papers: Part A

The concept of measuring the friction between a bulk solid and a wall material is very simple. However, experience together with previous wall friction measurement research suggest that variables that influence wall friction values are difficult to quantify and, so far, are proving unreliable to predict with any degree of confidence. In this paper some preliminary test results are presented for different bulk solids on different wall plates where variables examined include particle size distribution, moisture content, test cell size and shear speed. The outcomes presented confirm the authors' belief that with the present state of knowledge about wall friction …


Anticipating The Friction Coefficient Of Friction Materials Used In Automobiles By Means Of Machine Learning Without Using A Test Instrument, Mustafa Ti̇mur, Fati̇h Aydin Jan 2013

Anticipating The Friction Coefficient Of Friction Materials Used In Automobiles By Means Of Machine Learning Without Using A Test Instrument, Mustafa Ti̇mur, Fati̇h Aydin

Turkish Journal of Electrical Engineering and Computer Sciences

The most important factor for designs in which friction materials are used is the coefficient of friction. The coefficient of friction has been determined taking such variants as velocity, temperature, and pressure into account, which arise from various factors in friction materials, and by analyzing the effects of these variants on friction materials. Many test instruments have been produced in order to determine the coefficient of friction. In this article, a study about the use of machine learning algorithms instead of test instruments in order to determine the coefficient of friction is presented. Isotonic regression was selected as the machine …