نتایج جستجو برای: surface asperity surface roughness dry friction coefficient

تعداد نتایج: 898730  

2013
Surinder Kumar

The present investigation deals with the study and development of a surface roughness prediction model for the machining of unidirectional glass fiber reinforced plastics (UDGFRP) composite using Artificial Neural Network (ANN). The feed forward back propagation is used. Taguchi method (Orthogonal L16 array) is employed to carry out the experimental work. The process parameters selected for stu...

2011
F. Stewart H. R. Le J. A. Williams A. Roberts

A friction test rig has been developed to carry out repeated sliding friction tests for premium tubular connections. The test rig enables accurate measurement of friction in various contact regimes which are relevant to the threaded connections between tubular components. Higher load tests can simulate the contact in metal-to-metal seals under very high contact pressures by using perpendicular ...

2010
S. Nielsen G. Di Toro W. A. Griffith

S U M M A R Y Under extreme conditions like those encountered during earthquake slip, frictional melt is likely to occur. It has been observed on ancient faults that the melt is mostly extruded toward local extensional jogs or lateral tension cracks. In the case of laboratory experiments with a rotary shear apparatus, melt is extruded from the sample borders. When this happens, a thin and irreg...

2014
Alexander E Kovalev Kirstin Dening Bo N J Persson Stanislav N Gorb

The surface topography of the human wrist skin is studied by using optical and atomic force microscopy (AFM) methods. By using these techniques the surface roughness power spectrum is obtained. The Persson contact mechanics theory is used to calculate the contact area for different magnifications, for the dry and wet skin. The measured friction coefficient between a glass ball and dry and wet s...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this thesis protic and aprotic ammonium-based ionic liquids were synthesized and their surface tensions were measured in the range of 298-373k. the protics are alkyl ammonium-based ils with the carboxylate (formate, acetate, propionate) anion and aprotics are quaternary ammonium-based ils with bis(trifluoromethylsulfonyl)imide anion. capillary rise method was used for surface tension measure...

2003
Brian S. Rice Kevin A. Cole Sinan Müftü

The traction developed between a thin flexible web, wrapped around a non-vented, rotating cylindrical roller is studied experimentally and theoretically. A series of eight webs representing a wide range of surface roughness characteristics are traction-tested against the same roller over a wide speed range. A mathematical model that couples air film pressure, web deflection, and asperity deform...

2013
Steve Pickering

The purpose of this research paper is to examine the tribological characteristics and issues related to journal bearings under boundary and mixed lubrication conditions during shaft startup, shutdown, and low speeds. The key issues and problems related to journal bearings, most notably wear, are discussed as well as the subsequent issues created in the field. The mechanical analysis of the load...

Journal: :تحقیقات مهندسی کشاورزی 0
هادی رمضانی اعتدالی دانشجوی دکتری عبدالمجید لیاقت دانشیار گروه آموزشی مهندسی آبیاری و آبادانی دانشکده مهندسی و فناوری کشاورزی دانشگاه تهران فریبرز عباسی دانشیار مؤسسه تحقیقات فنی و مهندسی کشاورزی کرج

the manning roughness coefficient is an important parameter in the design and evaluation of furrow irrigation. despite its importance, estimation of this parameter for surface irrigation is very difficult, particularly in furrow irrigation. in this study, an evalue model was used to estimate the manning roughness coefficient in furrow irrigation. the model was based on volume balance and develo...

Journal: :The European physical journal. E, Soft matter 2011
B Lorenz B N J Persson S Dieluweit T Tada

We have measured the friction force acting on a rubber block slid on a concrete surface. We used both unfilled and filled (with carbon black) styrene butadiene (SB) rubber and have varied the temperature from -10 °C to 100 °C and the sliding velocity from 1 μm/s to 1000 μm/s. We find that the experimental data at different temperatures can be shifted into a smooth master-curve, using the temper...

Journal: :Dental materials : official publication of the Academy of Dental Materials 2005
Andrea Wichelhaus Marc Geserick Raimund Hibst Franz G Sander

OBJECTIVES Since the low friction of NiTi wires allows a rapid and efficient orthodontic tooth movement, the aim of this research was to investigate the friction and surface roughness of different commercially available superelastic NiTi wires before and after clinical use. The surface of all of the wires had been pre-treated by the manufacturer. MATERIALS Forty superelastic wires (Titanol Lo...

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