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Journal articles on the topic 'Roughness coefficient n'

Author: Grafiati

Published: 4 June 2021

Last updated: 8 February 2022

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1

Ye, Aizhong, Zheng Zhou, Jinjun You, Feng Ma, and Qingyun Duan. "Dynamic Manning's roughness coefficients for hydrological modelling in basins." Hydrology Research 49, no. 5 (2018): 1379–95. http://dx.doi.org/10.2166/nh.2018.175.

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Abstract Manning's roughness coefficient (n) has a significant impact on routing in hydrological models. However, computational methods for dynamic roughness coefficients are of little concern in current research. Few studies have produced spatial-temporal distributions of the roughness coefficients in basins. In this study, a formula to calculate the n value was established based on a statistical analysis of estimated n values by Manning's formula. The routing model of a distributed hydrological model was then improved using the new formula to calculate n. The roughness coefficient is not a c

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2

Sadeh, Yuval, Hai Cohen, Shimrit Maman, and Dan Blumberg. "Evaluation of Manning’s n Roughness Coefficient in Arid Environments by Using SAR Backscatter." Remote Sensing 10, no. 10 (2018): 1505. http://dx.doi.org/10.3390/rs10101505.

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The prediction of arid region flash floods (magnitude and frequency) is essential to ensure the safety of human life and infrastructures and is commonly based on hydrological models. Traditionally, catchment characteristics are extracted using point-based measurements. A considerable improvement of point-based observations is offered by remote sensing technologies, which enables the determination of continuous spatial hydrological parameters and variables, such as surface roughness, which significantly influence runoff velocity and depth. Hydrological models commonly express the surface roughn

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3

Leitans, A., J. Lungevics, J. Rudzitis, and A. Filipovs. "Tribological Properties of PVD Ti/C-N Nanocoatnigs." Latvian Journal of Physics and Technical Sciences 54, no. 2 (2017): 64–71. http://dx.doi.org/10.1515/lpts-2017-0014.

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Abstract The present paper discusses and analyses tribological properties of various coatings that increase surface wear resistance. Four Ti/C-N nanocoatings with different coating deposition settings are analysed. Tribological and metrological tests on the samples are performed: 2D and 3D parameters of the surface roughness are measured with modern profilometer, and friction coefficient is measured with CSM Instruments equipment. Roughness parameters Ra, Sa, Sz, Str, Sds, Vmp, Vmc and friction coefficient at 6N load are determined during the experiment. The examined samples have many pores, w

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4

Zhu, Xinghua, Bangxiao Liu, and Yue Liu. "New Method for Estimating Roughness Coefficient for Debris Flows." Water 12, no. 9 (2020): 2341. http://dx.doi.org/10.3390/w12092341.

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Flow resistance is a fundamental control of flow hydraulics in streams and rivers. In this paper, five dimensionless factors affecting the Manning roughness coefficient n and attributed to the external roughness coefficient n1 and the internal roughness coefficient n2 were analyzed comprehensively. And then, dimensionless factors affecting n1 and n2 with precise physical meanings were proposed. With a calculation method for roughness coefficient fitted and analyzed based on observation data from published research papers, the analysis results showed that the external resistance coefficient is

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5

Lau, T. W., and N. R. Afshar. "Effect of Roughness on Discharge." Journal of Civil Engineering, Science and Technology 4, no. 3 (2013): 29–33. http://dx.doi.org/10.33736/jcest.124.2013.

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These Water resource projects and hydraulic engineering works have been developing rapidly throughout the world, thus prediction of water roughness coefficient is becoming an importance criteria for the designs of hydraulic related structure like open channel, and dam structure. The purposes of this research are to determine the effect of roughness on discharge and study on the factors that affect roughness coefficient. The roughness coefficient for this study is expressed in terms of Manning’s n. Experimental works were carried out to study the effect of roughness by using flumes (8m x 0.3m x

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6

Li, Yujian, Yixin Geng, and Liang Mao. "Calibration method for Manning's roughness coefficient for a river flume model." Water Supply 20, no. 8 (2020): 3597–603. http://dx.doi.org/10.2166/ws.2020.235.

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Abstract This paper takes the Tarim River as an example to study the selection of Manning's roughness coefficient (n) in numerical simulation and presents a new method for calibrating Manning's roughness coefficient of a flume model. The measured topographic data and hydraulic data obtained from the flume experiments are taken as the initial boundary conditions in flow simulation, and n value for a flume model of the Qiman reach of Tarim River is calibrated by using a CCHE2D model. The consistency between the simulated water surface and the measured water surface with different n value is comp

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7

Hadi Sahib, Jumana, ., and . "Prediction the Manning’s Coefficient by HEC-RAS for Al-Meshkab River." International Journal of Engineering & Technology 7, no. 4.37 (2018): 76. http://dx.doi.org/10.14419/ijet.v7i4.37.23620.

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The Manning's coefficient represents the roughness characteristics of the channel, which directly affects open channel calculations. In this study, it been calculated which estimation of Manning's coefficient (n) by some of the collected data .The remaining data is utilized for check of the model testing with actual data, which is called verification. The model was adopted by a one-dimensional mathematical by using the HEC-RAS program. The region was studied at the upstream of the Al-Meshkab Barrage, where data were collected in 2010. The coefficient of Manning's roughness (n) is given well ag

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8

Ma, Jing, and Ling Qiang Yang. "Manning’s N Value of Bridge-in-Backpack." Applied Mechanics and Materials 638-640 (September 2014): 965–68. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.965.

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Bridge-in-a-Backpack is a new type bridge. this study will investigate the interaction of flow under the bridge with the tubes and decking, and recommend Manning’s roughness coefficient for water flow under the composite backbridge system.

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9

HAMZAH, ESAH, ALI OURDJINI, MUBARAK ALI, PARVEZ AKHTER, MOHD RADZI HJ. MOHD TOFF, and MANSOR ABDUL HAMID. "INFLUENCE OF NITROGEN FLOW RATE ON FRICTION COEFFICIENT AND SURFACE ROUGHNESS OF TiN COATINGS DEPOSITED ON TOOL STEEL USING ARC METHOD." Surface Review and Letters 14, no. 05 (2007): 1007–13. http://dx.doi.org/10.1142/s0218625x07010408.

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In the present study, the effect of various N 2 gas flow rates on friction coefficient and surface roughness of TiN -coated D2 tool steel was examined by a commercially available cathodic arc physical vapor deposition (CAPVD) technique. A Pin-on-Disc test was carried out to study the Coefficient of friction (COF) versus sliding distance. A surface roughness tester measured the surface roughness parameters. The minimum values for the COF and surface roughness were recorded at a N 2 gas flow rate of 200 sccm. The increase in the COF and surface roughness at a N 2 gas flow rate of 100 sccm was ma

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10

Wu, Xuesong, and Ming Dong. "A local scattering theory for the effects of isolated roughness on boundary-layer instability and transition: transmission coefficient as an eigenvalue." Journal of Fluid Mechanics 794 (March 30, 2016): 68–108. http://dx.doi.org/10.1017/jfm.2016.125.

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This paper is concerned with the rather broad issue of the impact of abrupt changes (such as isolated roughness, gaps and local suctions) on boundary-layer transition. To fix the idea, we consider the influence of a two-dimensional localized hump (or indentation) on an oncoming Tollmien–Schlichting (T–S) wave. We show that when the length scale of the former is comparable with the characteristic wavelength of the latter, the key physical mechanism to affect transition is through scattering of T–S waves by the roughness-induced mean-flow distortion. An appropriate mathematical theory, consistin

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11

Zheng, Li Yun, Li Xin Zhao, and Jing Jun Zhang. "Friction and Wear Behavior of TiN/TiAlN Coated Ti(C,N)-Based Cermets." Key Engineering Materials 368-372 (February 2008): 1307–9. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1307.

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Ti(C,N)-based cermets were coated with a TiN/TiAlN coating using ion plating technology. The sliding wear test was performed for the coated cermets and the microstructure, composition and surface roughness of the coated cermets under different velocities and loads were characterized. The results showed that the friction coefficients of the coated cermets were lower than that of the neat cermets. Under the same load, the adhesion phenomenon of the counterpart materials on the specimens was improved and the mean friction coefficient increased with increasing sliding speed. Under the same sliding

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12

Al-Asadi, Khalid, and Jennifer G. Duan. "Assessing methods for estimating roughness coefficient in a vegetated marsh area using Delft3D." Journal of Hydroinformatics 19, no. 5 (2017): 766–83. http://dx.doi.org/10.2166/hydro.2017.064.

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A Delft3D-FLOW model was used to simulate tidal flow in Davis pond marsh in Louisiana, USA. The study area is a freshwater marsh consisting of one main channel and floodplain. Vegetation-induced flow resistance greatly influences tidal flow dynamics in the marsh. This study evaluated eight approaches to estimate vegetation roughness, including two constant Manning's n values, four empirical relations for calculating n, and two methods for calculating Chezy's C values originally embedded in the Delft3D model. Simulated results of water surface elevation (WSE) were compared with the correspondin

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13

Waghmare, Ajay K., and Prasanta Sahoo. "Adhesive Friction Based on Accurate Elastic-Plastic Finite Element Analysis and n-Point Asperity Concept." International Frontier Science Letters 11 (March 2017): 1–28. http://dx.doi.org/10.18052/www.scipress.com/ifsl.11.1.

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The present work considers analysis of adhesive friction of rough surfaces using n-point asperity concept for statistical definition of surface roughness features, and accurate finite element analysis of elastic-plastic deformation of single asperity contact. The paper describes theoretical study in which whole range of deformation of an n-point asperity viz. from fully elastic, through elastic-plastic, to fully plastic is considered and the intermediate transition regime is treated analytically as well as numerically. Well defined adhesion index and plasticity index are used to study the pros

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14

Shamkhi, Mohammed Siwan, and Zainab Shakir Attab. "Estimation of Manning’s Roughness Coefficient for Tigris River by Using HEC-RAS model." Wasit Journal of Engineering Sciences 6, no. 3 (2018): 90–97. http://dx.doi.org/10.31185/ejuow.vol6.iss3.107.

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Tigris River (downstream of the kut barrage reach) there is no study conducted on it to estimate its Manning n value. HEC-RAS was used to analysis study reach and calibrate n value of the study reach .filed data were collected during 2016-2017 (duration of study), eights data sets were observed included stage and discharge measurements. The discharge is controlled by Kut Barrage Operation. The range of water surface elevation is (+10.300 to +12.511) and flow discharge range is (202.7 - 355.280) m3/sec. The range of n value for study reach is (0.021-0.034). The calibration results provided suit

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15

Pradhan, Arpan, and Kishanjit K. Khatua. "Gene expression programming to predict Manning’s n in meandering flows." Canadian Journal of Civil Engineering 45, no. 4 (2018): 304–13. http://dx.doi.org/10.1139/cjce-2016-0569.

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Accurate prediction of Manning’s roughness coefficient is essential for the computation of conveyance capacity in open channels. There are various factors affecting the roughness coefficient in a meandering compound channel and not just the bed material. The factors, geometric as well as hydraulic, are investigated and incorporated in the prediction of Manning’s n. In this study, a new and accurate technique, gene expression programming (GEP) is used to estimate Manning’s n. The estimated value of Manning’s n is used in the evaluation of the conveyance capacity of meandering compound channels.

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16

Hussain, Abrar, Vitali Podgursky, Dmitri Goljandin, et al. "Tribological and Mechanical Properties Investigations of Post-Consumer Cotton Textiles." Solid State Phenomena 320 (June 30, 2021): 97–102. http://dx.doi.org/10.4028/www.scientific.net/ssp.320.97.

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In this manuscript surface roughness, coefficient of friction (COF) and tensile properties of a post-consumer cotton fabric are evaluated. Fabric roughness, COF, effective tensile force and breaking force measured by optical profilometer, CETR tribometer and Instron tensile machine, respectively. The results proved that COF could rely on fabric pattern. Moreover, microscopically roughness influences on friction and tensile properties due to surface defects. It was found that increase in roughness of textile cotton relates to increase of number of random directional fibers. These fibers intensi

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17

Wang, Hua, Feng Qiang Ji, Kun Xia, and Meng An Wu. "Water Environment Numerical Simulation for a Complicated River-Lake System." Advanced Materials Research 1010-1012 (August 2014): 403–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.403.

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Zhushan Bay watershed to the northwest of Lake Taihu was selected as the research area. Taking the close connection of water quality and quantity of river-lake system into consideration, we constructed a water environmental coupling model of 1-D river network and 2-D lake to simulate hydrodynamic and water quality of river-lake system. Based on the results of field measured data, the constructed model was calibrated and validated. According to results of calibration, the range of river roughness was 0.02~0.028, the degradation coefficient of COD, NH3-N and TP degradation coefficient was 0.09~0

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18

Mohanta, Abinash, Kanhu Patra, and Bibhuti Sahoo. "Anticipate Manning’s Coefficient in Meandering Compound Channels." Hydrology 5, no. 3 (2018): 47. http://dx.doi.org/10.3390/hydrology5030047.

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Estimating Manning’s roughness coefficient ( n ) is one of the essential factors in predicting the discharge in a stream. Present research work is focused on prediction of Manning’s n in meandering compound channels by using the Group Method of Data Handling Neural Network (GMDH-NN) approach. The width ratio ( α ) , relative depth ( β ) , sinuosity ( s ) , Channel bed slope ( S o ) , and meander belt width ratio ( ω ) are specified as input parameters for the development of the model. The performance of GMDH-NN is evaluated with two different machine learning techniques, namely the support vec

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19

Park, Choa, Howon Park, Juhyun Lee, Hyunwoo Seo, and Siyoung Lee. "Surface Roughness and Microbial Adhesion After Finishing of Alkasite Restorative Material." JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY 47, no. 2 (2020): 188–95. http://dx.doi.org/10.5933/jkapd.2020.47.2.188.

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This study is aimed to evaluate and compare the surface roughness and microbial adhesion to alkasite restorative material (Cention N), resin-modified glass ionomer (RMGI), and composite resin. And to examine the correlation between bacterial adhesion and surface roughness by different finishing systems.<br/>Specimens were fabricated in disk shapes and divided into four groups by finishing methods (control, carbide bur, fine grit diamond bur, and white stone bur). Surface roughness was tested by atomic force microscope and surface observation was performed by scanning electron microscope.

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20

Papaioannou, George, Lampros Vasiliades, Athanasios Loukas, and Giuseppe T. Aronica. "Probabilistic flood inundation mapping at ungauged streams due to roughness coefficient uncertainty in hydraulic modelling." Advances in Geosciences 44 (April 26, 2017): 23–34. http://dx.doi.org/10.5194/adgeo-44-23-2017.

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Abstract. Probabilistic flood inundation mapping is performed and analysed at the ungauged Xerias stream reach, Volos, Greece. The study evaluates the uncertainty introduced by the roughness coefficient values on hydraulic models in flood inundation modelling and mapping. The well-established one-dimensional (1-D) hydraulic model, HEC-RAS is selected and linked to Monte-Carlo simulations of hydraulic roughness. Terrestrial Laser Scanner data have been used to produce a high quality DEM for input data uncertainty minimisation and to improve determination accuracy on stream channel topography re

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21

NASRIN, RAHIMA, HUMAYUN KABIR, and A. H. BHUIYAN. "SYNTHESIS OF IODINE DOPED n-BMA THIN FILMS VIA PLASMA POLYMERIZATION TECHNIQUE: EFFECT ON OPTICAL PROPERTIES." Surface Review and Letters 27, no. 04 (2019): 1950133. http://dx.doi.org/10.1142/s0218625x19501336.

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In order to understand the variation of surface morphology and optical properties due to modification, an attempt has been made to synthesize iodine-doped n-butyl methacrylate thin films through plasma polymerization technique. Field emission scanning electron microscope images displayed that the surface of the modified plasma polymerized n-butyl methacrylate (PPnBMA) thin films became smooth after iodine doping. Atomic force microscopic analysis reveals that with increasing doping time from 0[Formula: see text]min to 60[Formula: see text]min the surface root-mean-square roughness value is dec

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22

Mykytiuk, A., and S. Kondratenko. "Optical properties of PEDOT:PSS-silicon solar cells." Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics, no. 4 (2018): 118–21. http://dx.doi.org/10.17721/1812-5409.2018/4.17.

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We study the optical and electrical losses in PEDOT:PSS/n-Si solar cells using spectroscopic ellipsometry and current-voltage measurements. The optical constants and thickness of the PEDOT:PSS films were studied using spectroscopic ellipsometry performed by a SE-2000 SEMILAB ellipsometer spanning the NIR–VIS–UV range with a resolution of 5 nm. The results were analyzed using a four-layer model involving the ntype silicon (001) substrate, interfacial layer between Si and polymer films, PEDOT:PSS thin film, and a surface roughness layer. The key to understand the origin of the losses is that the

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23

You, Y. Z., D. I. Kim, and H. G. Chun. "A study on the Surface Properties of Nitrogen Implanted H13 Steel by Plasma Immersion Ion Implantation." Solid State Phenomena 118 (December 2006): 275–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.118.275.

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The near surface of the H13 steel was implanted by using Plasma immersion ion implantation (PIII) system at constant bias voltage of −20 kV with varying nitrogen (N+ ) ion dose (3, 6, 9, 12, 15×1017 ions/cm2 ). The surface properties of the N+ ion implanted steel were investigated by measuring the microhardness, wear loss and friction coefficient. As increasing N+ ion dose (12×1017 ions/cm2), both wear property and surface hardness were increased. However, these properties were decreased as the incident ion dose increased over 12×1017 ions/cm2. The elemental depth profile and surface roughness

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24

Ma, Dian Guang, Chun Xin Zhong, Wu Ning, Qing Ye, and Sheng Zhu. "Experimental Study on Hydraulic Roughness of Submerged Grass in Ecological Riverbank." Advanced Materials Research 838-841 (November 2013): 1743–48. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1743.

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A model experiment about the hydraulic roughness of natural turf used in riverbank was carried out in flume. To examine the rationality of experimental design, the hydraulic roughness coefficient of plexiglass-flume was tested firstly. The result was 0.0085, which is quite normal. Then the tested hydraulic roughness caused by vegetation ranges from 0.020 to 0.090 for the chosen plants, which is also acceptable. Furthermore, the tested incipient velocities of krasnozem, and paddysoil had the range of 0.55~0.65m·s-1 and 1.0~1.1m·s-1, respectively. All these experimental results are in normal ran

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25

Carreno-Luengo, Hugo, Guido Luzi, and Michele Crosetto. "Impact of the Elevation Angle on CYGNSS GNSS-R Bistatic Reflectivity as a Function of Effective Surface Roughness over Land Surfaces." Remote Sensing 10, no. 11 (2018): 1749. http://dx.doi.org/10.3390/rs10111749.

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The Earth’s surface bistatic reflectivity Γ L H C P , C y G N S S is experimentally characterized using the novel Global Navigation Satellite Systems Reflectometry (GNSS-R) L-band passive multistatic radar technique from the Cyclone Global Navigation Satellite Systems (CyGNSS) eight-microsatellite constellation. The focus of this study is to evaluate the influence of the GNSS satellites’ elevation angle θ e on Γ L H C P , C y G N S S , as a function of soil moisture content (SMC) and effective surface roughness parameter h . As the average response, the change of the scattering regime at a glo

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26

Santos, Mariana, Ana Sofia Coelho, Anabela Baptista Paula, et al. "Mechanical and Tribological Characterization of a Dental Ceromer." Journal of Functional Biomaterials 11, no. 1 (2020): 11. http://dx.doi.org/10.3390/jfb11010011.

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Background: Indirect restorations using composites with ceramic fillings can be an alternative to ceramic veneering and direct composite restorations for the treatment of posterior teeth. The aim of this study was the evaluation of the mechanical and tribological properties of a ceromer. Materials and Methods: Sixty specimens were produced and divided into two groups: one control group not submitted to thermocycling (n = 20) and one test group submitted to 5000 cycles of thermocycling (n = 40). The studied parameters were microhardness, surface roughness and the coefficient of friction (scratc

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27

Wijesekera, H. W., E. Jarosz, W. J. Teague, et al. "Measurements of Form and Frictional Drags over a Rough Topographic Bank." Journal of Physical Oceanography 44, no. 9 (2014): 2409–32. http://dx.doi.org/10.1175/jpo-d-13-0230.1.

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Abstract Pressure differences across topography generate a form drag that opposes the flow in the water column, and viscous and pressure forces acting on roughness elements of the topographic surface generate a frictional drag on the bottom. Form drag and bottom roughness lengths were estimated over the East Flower Garden Bank (EFGB) in the Gulf of Mexico by combining an array of bottom pressure measurements and profiles of velocity and turbulent kinetic dissipation rates. The EFGB is a coral bank about 6 km wide and 10 km long located at the shelf edge that rises from 100-m water depth to abo

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28

Ageev, E. V., and A. S. Pereverzev. "ANALYSIS OF CHARACTERISTICS OF WEAR RESISTANCE OF SINTERED ITEMS FROM ELECTROEROSION LEAD BRONZE OBTAINED IN KEROSIN LIGHT." IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, no. 7(242) (July 29, 2020): 25–28. http://dx.doi.org/10.35211/1990-5297-2020-7-242-25-28.

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The article presents the results of a study of the wear resistance of sintered samples of lead erosion bronze. Dispersed particles were obtained by electroerosive dispersion of BrS30 alloy waste in a carbon-containing medium - illuminating kerosene. Then, the obtained erosion materials were pressed using a Herzog TP 20 hand-held table press at a pressure of 1500 MPa and sintered in a Nabertherm GmbH RS 80/300/13 furnace for 2 hours at a temperature of 827 ° C in argon atmosphere. Then studied the surface roughness of the obtained samples, the friction coefficient and the wear factor of the sam

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Penglao, Witsarut, Luangvaranunt Tachai, and Boonrat Lohwongwatana. "Effect of Linear Sliding Speed on Wear Behavior of Al₂O₃/TiC Ceramic Composite and Diamond Slicing Blade." Advanced Materials Research 1025-1026 (September 2014): 292–97. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.292.

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Pin-on-disk technique was used as a tool to study the tribological properties of contacting surfaces of alumina-titanium carbide composite material and diamond slicing blade. Conditions for testing are linear sliding speed between 0.2 and 0.4 m/s under applied load of 10 N and sliding distance up to 5000 m. The physical properties of both specimens which are mass loss, surface roughness and morphology of worn surface are investigated. The effect of linear sliding speed is analyzed in term of friction coefficient, surface roughness, and specific wear rate. It was found that, at initial state of

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30

Abbas, Sarmad A., Ali H. Al-Aboodi, and Husham T. Ibrahim. "Identification of Manning’s Coefficient Using HEC-RAS Model: Upstream Al-Amarah Barrage." Journal of Engineering 2020 (April 3, 2020): 1–7. http://dx.doi.org/10.1155/2020/6450825.

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In understanding the hydraulic characteristics of river system flow, the hydraulic simulation models are essential tools. This study submits the results of the proposition of a hydraulic model in order to determine the roughness coefficient (Manning’s coefficient n) of the Tigris River along 3.5 km within the Maysan Governorate, south of Iraq. HEC-RAS software was the simulation tool used in this study. The HEC-RAS model was adopted, calibrated, and validated in adopting two sets of observed water levels. Graphical and statistical approaches were used for model calibration and verification. Re

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Zhang, Jingzhou, Shengtang Zhang, Si Chen, et al. "Overland Flow Resistance Law under Sparse Stem Vegetation Coverage." Water 13, no. 12 (2021): 1657. http://dx.doi.org/10.3390/w13121657.

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To explore the characteristics of overland flow resistance under the condition of sparse vegetative stem coverage and improve the basic theoretical research of overland flow, the resistance characteristics of overland flow were systematically investigated under four slope gradients (S), seven flow discharges (Q), and six degrees of vegetation coverage (Cr). The results show that the Manning roughness coefficient (n) changes with the ratio of water depth to vegetation height (h/hv) while the Reynolds number (Re), Froude number (Fr), and slope (S) are closely related to vegetation coverage. Mean

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32

Podgursky, V., E. Adoberg, A. Surženkov, et al. "Dependence of the friction coefficient on roughness parameters during early stage fretting of (Al,Ti)N coated surfaces." Wear 271, no. 5-6 (2011): 853–58. http://dx.doi.org/10.1016/j.wear.2011.03.006.

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Saha, Biswajit, and Jung Hoon Lee. "Improvement of Surface Properties of Micro-Mold via SAM Coating for Fabrication of Microfluidic Device." Applied Mechanics and Materials 752-753 (April 2015): 159–62. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.159.

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N-octadecyltrichlorosilane [OTS, CH3(CH2)17SiCl3] self-assembled monolayer (SAM) coatings were deposited on Si micromolds by dip-coating. Chemical composition, surface roughness, friction coefficient, thermal stability and surface energy of coatings were investigated. OTS coated silicon (Si) micromolds were used to fabricate PMMA microfluidic devices by hot-embossed process. All OTS coatings were thermally stable up to 180 °C, which is higher than hot-embossing temperature of PMMA. OTS coated micromolds had low friction coefficient, adhesion and superior molding efficiency, which improved life

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Askari, Syed Jawid. "Tribological Characteristics of CVD Nanocrystalline Diamond Film Grown by Bias Enhanced Nucleation Process." Advanced Materials Research 264-265 (June 2011): 1439–43. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.1439.

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Nanocrystalline diamond (NCD) films on titanium alloys are of importance for tribology and biomedical implants. However, due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving high nucleation density, it is difficult to deposit adherent NCD films on titanium and its alloys. The aim of this research work is to successfully produce smooth, low roughness and well adherent NCD film on a pure Ti substrate by bias enhanced nucleation (BEN) process using microwave plasma chemical

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Khusankhudzaev, Ulmas, Odil Kadirov, and Azizjon Jakhonov. "Results of full-scale and laboratory studies of the spillway of HPP No. 2." E3S Web of Conferences 264 (2021): 03028. http://dx.doi.org/10.1051/e3sconf/202126403028.

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In the article, based on the results of field measurements and calculations, recommendations are given for determining the roughness coefficient of the channel of the spillway. Based on the analysis of the literature and field research data, it was recommended to take the roughness coefficient of the channel of the spillway (canal) equal to n = 0.02 - for areas with steep slopes and without sediment deposits, and in areas with the worst condition of concrete surfaces and sediment deposits, take n = 0.0225. According to the results of field surveys of the canal, it was found that the hydraulic

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Luangvaranunt, Tachai, Natthawat Tangkaratanakul, and Patchanok Sakultantimetha. "Wear of Diamond Grinding Wheel during Low Speed Dressing by Alumina." Key Engineering Materials 658 (July 2015): 120–24. http://dx.doi.org/10.4028/www.scientific.net/kem.658.120.

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Diamond grinding wheel is used in high precision grinding process, when work piece has a very high hardness. For a specific grinding interval, the wheel must be properly dressed, in order to remove swarf, sharpen the worn diamond grits, open up new diamond protrusions, and recondition the bond material. Dressing of diamond grinding wheel by alumina dressing tool has been simulated in a pin-on-disk machine in the research. Sharpening of the wheel is indicated by the increase of its roughness value, and surface microstructure with protruding sharp diamond grits. It was found that increasing of s

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EKİNCİ, ŞERAFETTIN. "TEMPERATURE-DEPENDENT EFFECT OF BORIC ACID ADDITIVE ON SURFACE ROUGHNESS AND WEAR RATE." Surface Review and Letters 24, Supp01 (2017): 1850005. http://dx.doi.org/10.1142/s0218625x18500051.

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Wear and friction hold an important place in engineering. Currently, scientific societies are struggling to control wear by means of studies on lubricants. Boric acid constitutes an important alternative with its good tribological properties similar to MO2S and graphite alongside with low environmental impacts. Boric acid can be used as a solid lubricant itself whereas it can be added or blended into mineral oils in order to yield better mechanical and tribological properties such as low shear stress due to the lamellar structure and low friction, wear and surface roughness rates. In this stud

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Furushima, Tsuyoshi, Tetsuro Masuda, Kenichi Manabe, and Sergei Alexandrov. "Inhomogeneous 3D Finite Element Model for Prediction of Free Surface Roughening." Advanced Materials Research 418-420 (December 2011): 1040–43. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1040.

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In this study, we evaluated the characteristics of 3D finite element (FE) model considering material inhomogeneity for prediction of free surface roughening. Free surface roughening behavior can be observed by this model. The variation in material inhomogeneity parameter value has a strong correlation with the rate of increase in the surface roughness. macroscopic strength coefficient K value does absolutely not affect the rate of increasing surface roughness. Strain hardening sensitivity index n value slightly affects the free surface roughening behavior. The true stress – true strain curve o

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Samarinas, N., and C. Evangelides. "Discharge estimation for trapezoidal open channels applying fuzzy transformation method to a flow equation." Water Supply 21, no. 6 (2021): 2893–903. http://dx.doi.org/10.2166/ws.2021.155.

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Abstract The aim of this paper is to implement fuzzy logic theory in order to estimate the discharge for open channels, which is a well-known physical problem affected by many factors. The problem can be solved by the Manning equation but the parameters present uncertainties as to their true-real values. Especially, the Manning n roughness coefficient, which is an empirically derived coefficient, presents quite a high variation for different substrates. With the help of fuzzy logic and utilizing a fuzzy transformation method, it is possible to include the uncertainties of the problem in the ca

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Li, Shuai, Jian Min Zhang, Wei Lin Xu, et al. "Sensitivity Analysis of Parameters in HEC-RAS Software." Applied Mechanics and Materials 641-642 (September 2014): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amm.641-642.201.

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As for the level of tail-water often rose when the situation of tailrace river changing during the process of construction of hydroelectric power station, one-dimensional mathematical model is used through two procedures to solve this problem. In the first, the sensitivity of three key parameters including roughness, cross-section spacing Δs, starting regulation level and section in the mathematical model were discussed. The results indicate that: (1) Positive relationship between ΔY/Y and n, shows the greater flow rate, the more sensitive of water depth changes to roughness coefficient; (2) T

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ZHOU, JICHENG, DITIAN LUO, YOUZHEN LI, and ZHENG LIU. "PROPERTIES OF Ta2O5 THIN FILMS DEPOSITED BY DC REACTIVE MAGNETRON SPUTTERING." International Journal of Modern Physics B 23, no. 27 (2009): 5275–82. http://dx.doi.org/10.1142/s0217979209053618.

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Ta 2 O 5 thin films were deposited at different oxygen flow ratio ( O 2/( O 2+Ar) = 10 ~ 80%) by DC reactive magnetron sputtering. Influence of oxygen flow ratio on depositing rate, surface characteristics, microstructure, and optical properties are discussed in this paper. With the increasing of oxygen, deposition rate decreases exponentially, the root mean square roughness and the maximum roughness decrease according to the atom force microscope images. XRD patterns indicate the as-deposited Ta 2 O 5 films are amorphous. Based on the envelop method, the samples' optical constants are calcula

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Sunthornpan, Narin, Shuichi Watanabe, and Nutthanun Moolsradoo. "Elements-Added Diamond-Like Carbon Film for Biomedical Applications." Advances in Materials Science and Engineering 2019 (March 3, 2019): 1–11. http://dx.doi.org/10.1155/2019/6812092.

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Elements-added diamond-like carbon films for biomedical applications were investigated. The aim of this work was to study the effects of the elemental contents (silicon and silicon-nitrogen) in a DLC film on its properties for biomedical applications. Pure DLC, Si-DLC, and Si-N-DLC films were prepared from C2H2, C2H2 : TMS, and C2H2 : TMS : N2 gaseous mixtures, deposited on an AISI 316L substrate using the plasma-based ion implantation (PBII) technique. The structure of films was analyzed using Raman spectroscopy. The chemical composition of films was measured using energy dispersive X-ray spe

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Pana, Iulian, Alina Vladescu, Lidia R. Constantin, Ioan G. Sandu, Mihaela Dinu, and Cosmin M. Cotrut. "In Vitro Corrosion and Tribocorrosion Performance of Biocompatible Carbide Coatings." Coatings 10, no. 7 (2020): 654. http://dx.doi.org/10.3390/coatings10070654.

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The present study aims to explain the corrosion and the tribocorrosion performance in simulated conditions of the human body by the level of stress, adhesion of coating to substrate, roughness, and hardness. The coatings were synthesized by the cathodic arc evaporation method on 316L stainless steel substrates to be used for load bearing implants. Structure, elemental, and phase compositions were studied by means of energy dispersive spectrometry and X-ray diffraction, respectively. The grain size and strain of the coatings were determined by the Williamson–Hall plot method. Tests on hardness,

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Patil, Prabhugouda Mallanagouda, S. H. Doddagoudar, and P. S. Hiremath. "Impacts of surface roughness on mixed convection nanofluid flow with liquid hydrogen/nitrogen diffusion." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 6 (2019): 2146–74. http://dx.doi.org/10.1108/hff-11-2018-0703.

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Purpose The purpose of this paper is to present the surface roughness effects on mixed convection nanofluid flow with liquid hydrogen/liquid nitrogen diffusion. Design/methodology/approach The small parameter (α) is considered along with the frequency parameter n to study the surface roughness. The non-similar transformations are used to reduce the dimensional non-linear partial differential equations into dimensionless form, and then, the resulting equations are solved with the help of Newton’s Quasilinearization technique and the finite difference scheme. Findings The impacts of several dime

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Zhan, Chao, Wen Jian Ke, Xin Ming Li, Wan Li Du, Li Juan Wang, and Cong Ye. "The Influence of Substrate Temperature on the Morphological and Optical Properties of ZnTiO₃ Thin Films Prepared by Magnetron Sputtering." Advanced Materials Research 804 (September 2013): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amr.804.3.

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Cubic ZnTiO3thin films have been prepared by radio frequency magnetron sputtering on n-type (100) Si substrate at different temperatures. The morphological and optical properties of ZnTiO3films in relation to substrate temperatures are investigated by spectroscopic ellipsometry (SE) and AFM as well as SEM in detail. X-ray diffraction (XRD) measurement shows that all the films have a cubic phase structure and the optimum substrate temperature to form crystalline ZnTiO3thin film is 250 °C. Through SEM and AFM, the particle size in thin films and film surface roughness increase with increasing th

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Chang, Boon Peng, Yik Fong Yong, Hazizan Md Akil, and Ramdziah Md Nasir. "Optimization on Abrasive Wear Performance of Pultruded Kenaf-Reinforced Polymer Composite Using Taguchi Method." Key Engineering Materials 739 (June 2017): 42–49. http://dx.doi.org/10.4028/www.scientific.net/kem.739.42.

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This study examined the optimal abrasive wear performance of kenaf-reinforced polymer composite under different sliding conditions. Three different fiber loadings i.e. 43.05, 49.30 and 55.33 vol.% of kenaf fiber was reinforced into a polyester resin using the pultrusion technique. Optimal responses of wear rate and average coefficient of friction (COF) for kenaf fiber-reinforced polyester composites, based on different levels of control factors (fiber loading, applied load, counterface roughness and sliding speed) were determined by the Taguchi Design of experiment (DOE) with L9 (34) orthogona

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Kurkute, Vijay, and Sandip Chavan. "Analysis and Optimization of Surface Roughness and Microhardness for Roller Burnishing using Response Surface Methodology and Desirability Function Approach on Aluminum 63400." Journal of Advanced Manufacturing Systems 18, no. 03 (2019): 363–78. http://dx.doi.org/10.1142/s0219686719500197.

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In the present study, response surface methodology (RSM) has been used to optimize roller burnishing process for aluminum alloy 63400 grade. Single roller burnishing tool (carbide) is used to burnish round aluminum alloy. Experiments were performed with Box and Wilson Central Composite Design (CCD). The machining factors controlled during experimentation are speed, feed, force and number of tool passes. The response parameters are surface roughness and microhardness. The most significant control factors on the surface roughness and microhardness were determined by analysis of variance (ANOVA).

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Lenart, Agnieszka, Pawel Pawlus, Andrzej Dzierwa, Slawomir Wos, and Rafal Reizer. "The Effect of Surface Texture on Lubricated Fretting." Materials 13, no. 21 (2020): 4886. http://dx.doi.org/10.3390/ma13214886.

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Experiments were conducted using an Optimol SRV5 tester in lubricated friction conditions. Steel balls from 100Cr6 material of 60 HRC hardness were placed in contact with 42CrMo4 steel discs of 47 HRC hardness and diversified surface textures. Tests were carried out at a 25–40% relative humidity. The ball diameter was 10 mm, the amplitude of oscillations was set to 0.1 mm, and the frequency was set to 80 Hz. Tests were performed at smaller (45 N) and higher (100 N) normal loads and at smaller (30 °C) and higher (90 °C) temperatures. During each test, the normal load and temperature were kept c

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Anurose, T. J., and D. Bala Subrahamanyam. "Assessment of a surface-layer parameterization scheme in an atmospheric model for varying meteorological conditions." Annales Geophysicae 32, no. 6 (2014): 669–75. http://dx.doi.org/10.5194/angeo-32-669-2014.

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Abstract. The performance of a surface-layer parameterization scheme in a high-resolution regional model (HRM) is carried out by comparing the model-simulated sensible heat flux (H) with the concurrent in situ measurements recorded at Thiruvananthapuram (8.5° N, 76.9° E), a coastal station in India. With a view to examining the role of atmospheric stability in conjunction with the roughness lengths in the determination of heat exchange coefficient (CH) and H for varying meteorological conditions, the model simulations are repeated by assigning different values to the ratio of momentum and ther

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Karim, Md Rezaul, Rifat Ahasan Siddique, and Farhana Dilwar. "Study of Surface Roughness and MRR in Turning of SiC Reinforced Al Alloy Composite Using Taguchi Design Method, ANN and PCA Approach under MQL Cutting Condition." Advanced Materials Research 1158 (April 2020): 115–31. http://dx.doi.org/10.4028/www.scientific.net/amr.1158.115.

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This paper emphases on the effect of various machining constraint on surface roughness and material removal rate in turning SiC reinforced Al alloy composite through taguchi orthogonal array based experimental analysis which has been further optimized using principal component analysis (PCA). Experimental investigation has been conducted under minimum quality lubricant (MQL) cutting environment. Palm oil has been used as lubricant where flow rate and pressure were kept at 120 ml/hr and 8 bar. The whole experiment has been designed using L25 orthogonal array having three input parameters and fi

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