Effect of Surface Roughness on the Total Hemispherical and Specular Reflectance of Metallic Surfaces

1964 ◽  
Vol 86 (2) ◽  
pp. 193-199 ◽  
Author(s):  
R. C. Birkebak ◽  
E. M. Sparrow ◽  
E. R. G. Eckert ◽  
J. W. Ramsey
Keyword(s):  
Surface Roughness ◽  
Black Body ◽  
Black Body Radiation ◽  
The Other ◽  
Angle Of Incidence ◽  
Metallic Surfaces ◽  
Specular Reflectance ◽  
Other Hand ◽  
Hemispherical Reflectance ◽  
Effect Of Surface

Measurements have been made of the hemispherical and specular reflectance of metallic surfaces of controlled roughness. The surfaces, which were ground nickel rectangles, were irradiated at various angles of incidence by a beam of black-body radiation, the temperature of which was also varied. The instrumentation which was devised to perform the experiments is described. The measurements show that beyond a certain surface roughness, the hemispherical reflectance is virtually independent of further increases in roughness. On the other hand, the specular reflectance decreases steadily with increasing roughness. Additionally, the hemispherical reflectance is found to be quite insensitive to the angle of incidence, while the specular reflectance increases with angle of incidence for the rougher surfaces.

The Influence of Toolpath Strategy on Geometric Accuracy in Incremental Forming

2013 ◽  
Vol 554-557 ◽  
pp. 1351-1361 ◽  
Author(s):  
Elif Malyer
Keyword(s):  
Surface Roughness ◽  
Sheet Metal ◽  
Metal Cutting ◽  
The Other ◽  
Geometric Accuracy ◽  
Geometrical Accuracy ◽  
Other Hand ◽  
Drawing Angle ◽  
Tool Diameter ◽  
Cam Software

Incremental sheet metal forming is a new process to manufacture sheet metal parts and it is becoming a remarkable technology for fast prototyping and small lot production because of the advantages of this technology such as process flexibility, product independent tooling and higher formability. On the other hand, limited maximum drawing angle, relatively coarse surface roughness, low geometrical accuracy and long forming time are common disadvantages of the process. Furthermore, it is affected by process parameters which are tool diameter, forming velocity, spindle speed, forming geometry and depth, etc. Toolpath strategy which is used to form sheet metal by CNC machine has a key role among these parameters. The present study has been undertaken in order to investigate the suitable toolpath strategy which is developed for metal cutting by commercial CAD/CAM software to increase geometrical accuracy and decrease thinning and forming time. For the intended purpose, seven different toolpath strategies which are rough and finish strategies were used to form a truncated frustum by using one millimeter thick S235JR steel alloy. The effect of each strategy on the surface roughness, geometrical accuracy and thinning distribution of formed product was studied by measuring thickness, drawing angle and depth of formed parts. Therefore, formed parts scanned by 3D laser scanner and STL files of parts were generated then STL files were converted into CAD file. CAD data of parts was used for measurements. The measurements showed that not only forming movements but also transition movements along the tool path affected the geometric accuracy and thinning distribution, surface roughness and forming time of formed parts. On the other hand it was observed that rough strategies were given good results as finish strategies and tool paths generated by CAM software need to be editing for better geometric accuracy, thinning, forming time and surface quality.

scholarly journals Usage of Fiber-Reinforced Resin Instruments in Interproximal Surfaces

2008 ◽  
Vol 02 (02) ◽  
pp. 096-101
Author(s):  
Deniz C. Can-Karabulut ◽  
Perihan Ozyurt ◽  
Ayhan Gurbuz ◽  
Abdulkadir Gullu
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Soft Tissues ◽  
Composite Resin ◽  
The Other ◽  
Fiber Reinforced ◽  
Surface Textures ◽  
Other Hand ◽  
Representative Samples ◽  
Sem Analyses

ABSTRACTObjectives: The aim of this study was to investigate the effects of fiber-reinforced resin burs on the surface roughness of a nanofilled composite.Methods: Average surface roughness values (Ra, �m) were measured using a surface profilometer and surface textures after finishing procedures were evaluated using a scanning electron microscope (SEM). Thirty cylindrical specimens were prepared using sectional teflon molds. A nanofilled composite was chosen. After the preparation specimens were divided into three subgroups randomly. After profilometric measurements, representative samples of the mentioned finishing procedures were selected and SEM analyses were carried out.Results: Mylar strip group was statistically different from the other two groups (P<.05). The smoothest surfaces occurred when composite resin samples were light cured against the strips. On the other hand there was no statistical difference between fiber-reinforced resin burs and Sof-Lex discs (P>.05). For fiber-reinforced resin burs scratches and pitting which may be due to plucking of the filler particles during finishing were observed on the surface topography of the composite resin material. On the other hand, for the Sof-Lex discs although scratches were noticed on the surface topography, no pitting was observed.Conclusions: Fiber-reinforced resin burs can be preferred for the grinding of composite surplus in interproximal surfaces, where the use of Sof-Lex discs can be harmful to soft tissues. (Eur J Dent 2008;2:96-101)

The Effect of Surface Roughness on Photoluminescence of Porous Silicon

2000 ◽  
Vol 638 ◽  
Author(s):  
Shunsuke Ogawa ◽  
Nobutomo Uehara ◽  
Masato Ohmukai ◽  
Yasuo Tsutsumi
Keyword(s):  
Surface Roughness ◽  
Porous Silicon ◽  
Blue Shift ◽  
The Other ◽  
Quantum Size ◽  
Silicon Nanostructure ◽  
Pl Emission ◽  
Ftir Absorption Spectra ◽  
Porous Silicon Nanostructure ◽  
Effect Of Surface

AbstractWe studied the effect of surface roughness of Si wafers on porous silicon by means of photoluminescence (PL), Fourier transformed infrared (FTIR) absorption and Raman spectroscopy. We prepared several kinds of Si wafers with a different surface roughness, and then the anodization was performed at a same condition. PL spectra show a blue shift with the increase of surface roughness. The particle size of porous silicon nanostructure becomes the smaller with increasing surface roughness at the same time. On the other hand, FTIR absorption spectra show no difference regardless of surface roughness. The PL emission dependent on the surface roughness originates from a quantum size effect. We infer that the surface roughness causes the concentration of the current during anodization in the area where the radius of the curvature at the surface is small.

Effect of Surface Etching Conditions on Stacking Faults in 4H-SiC Epitaxy

2019 ◽  
Vol 963 ◽  
pp. 119-122
Author(s):  
Tawhid Rana ◽  
Gil Yong Chung ◽  
Steve Anderson ◽  
Ian Manning ◽  
Willie Bowen ◽  
...  
Keyword(s):  
Stacking Faults ◽  
Gas Mixtures ◽  
Stacking Fault ◽  
High Density ◽  
Experimental Results ◽  
The Other ◽  
Surface Etching ◽  
Other Hand ◽  
Effect Of Surface

Epilayers grown on substrates etched by various etching conditions were studied for stacking fault defects. Substrates were etched by H2, H2+ HCl and H2 + CxHy gases prior to epilayer growth for comparison. High density of SF was observed in the epilayers when H2+HCl or H2+CxHy gas mixtures were used. On the other hand, much lower density of stacking faults (SF) (<1 cm-2) was observed in the epilayer grown on the surface etched by only H2 gas. However, a high number of pits were generated in the epilayer grown on substrate etched by H2 only, which can be considered to be tradeoff of achieving low SF in epilayer by substrate etching. We also conclude from our experimental results that C rich surface is more favorable to generate SF in epilayer compared to Si rich surface.

The Relations Between Entropy and Energy of Black-Body Radiation

2006 ◽  
Author(s):  
Richard A. Gaggioli
Keyword(s):  
Internal Energy ◽  
Transfer Rate ◽  
Unit Volume ◽  
Energy Content ◽  
Black Body ◽  
Black Body Radiation ◽  
The Other ◽  
Proportionality Factor ◽  
Entropy Transfer ◽  
The Difference

The entropy content of electromagnetic ("black-body") radiation at equilibrium in an enclosure is represented, on a per unit volume basis, by s = [4/3]aT3 and the internal energy content by u = aT4, so s = [4/3]u/T. The entropy transfer rate Sτ associated with emission from the radiation is related to the internal energy trans-fer rate Q by Sτ = Q/T. In both cases, content and flux, the entropy is proportional to energy divided by temperature. But, in one case the proportionality factor is [4/3] and in the other it is unity. The question has been raised, "Why, this difference?" The following develop-ment explains the source of the difference.

Adhesion and Autohesion of Rubber Compounds: Effect of Surface Roughness

1995 ◽  
Vol 68 (1) ◽  
pp. 13-25 ◽  
Author(s):  
A. N. Gent ◽  
S-M. Lai
Keyword(s):  
Surface Roughness ◽  
Smooth Surface ◽  
Peel Strength ◽  
The Other ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Roughened Surface ◽  
Styrene Butadiene ◽  
Effect Of Surface ◽  
Strength Of Adhesion

Abstract Sheets of various rubber compounds were pre-molded using different mold surfaces: Mylar film, smooth steel, and roughened steel. Two sheets of the same compound were then bonded together by crosslinking them in contact. Measurements of peel strength were carried out over a range of temperatures from −40°C to + 130°C. When an uncured sheet was crosslinked in contact with a smooth fully-cured sheet, the peel strength was generally lower than the tear strength of either sheet and the degree of interlinking was inferred to be only about one-half of the degree of crosslinking. On the other hand, when a sheet was cured in contact with a rough surface the strength of adhesion was 2× to 3× higher than with a smooth surface, probably because of increased area for bonding. Thus, when a rubber compound was cured in contact with a fully-cured sheet having a roughened surface, the two effects largely cancelled out and the resultant bond was about as strong as the material itself. Examples are given for carbon-black-filled and unfilled compounds based on polybutadiene, a styrene-butadiene copolymer, and natural rubber.

scholarly journals Effect of Cutting Conditions and Cooling Fluid on the Surface Roughness of AA2024 in Turning Process

2018 ◽  
Vol 26 (7) ◽  
pp. 87-94
Author(s):  
Wafa Mahdi Jodia
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Spindle Speed ◽  
The Other ◽  
Cutting Conditions ◽  
Turning Process ◽  
Constant Depth ◽  
Cooling Fluid ◽  
Effective Factor ◽  
Other Hand

This research studied the effect of cutting conditions and cooling fluid on the surface roughness for Aluminum alloy2024 worked by a turning machine in dry and wet cutting cases. The work was performed with different spindle speeds and feed rates with a constant depth of cutting. The cooling fluid used in this work was emulsion water (water/oil). The results proved that the cutting conditions and the coolant have a significant effect to maintain the surface with a least roughness (Ra) possible even without the use of the coolant. On the other hand, the results showed that the feed rate was very effective factor compared to the spindle speed.

Flashing Phenomena of Liquid Nitrogen in a Pressure Vessel Under Rapid Depressurizations

2015 ◽  
Author(s):  
Toshiaki Watanabe ◽  
Hironori Maehara ◽  
Makoto Nakamura ◽  
Hiromitsu Ohta ◽  
Shigeru Itoh
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Liquid Nitrogen ◽  
Pressure Vessel ◽  
The Other ◽  
Stream Of Consciousness ◽  
Cryogenic Fluids ◽  
Environmental Agreement ◽  
Device Technology ◽  
Effect Of Surface

In recent years in Japan, the demand of cryogenic fluids like a LH2, LNG is increasing because of the advance of fuel cell device technology, hydrogen of engine, and stream of consciousness for environmental agreement. The purpose of this study is to clarify some fundamental features of the flashing of cryogenic fluids. Experiments on flashing of liquid nitrogen were conducted to clarify the effect of surface roughness of a vessel. Two types of pressure vessel were used. One is a vessel made of stainless steel, the other is a vessel made of glass. In the case of glass vessel, many types of boiling have been observed. The degree of superheat at the start of boiling was found to depend strongly on the rate of depressurization.

Performance Analysis of Magnetic Hydrodynamic Tilted Bearing with Surface Roughness

2012 ◽  
Vol 579 ◽  
pp. 407-415 ◽  
Author(s):  
Hsiu Lu Chiang ◽  
Tsu Liang Chou ◽  
Ching Been Yang
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Performance Analysis ◽  
Pressure Distribution ◽  
Reynolds Equation ◽  
Newtonian Fluids ◽  
The Other ◽  
Other Hand ◽  
Load Carrying

The performances characteristics of magnetic hydrodynamic tilted bearing with surface roughness lubricated with ferrofluid are studied in this study. To explore the effects of ferrofluid to the bearings, the Shah’s theoretical model and the modified items of characteristics related to magnetic ferrofluid are adopted. As the affections of surface roughness to the bearings, the stochastic Christensen Reynolds’ equation is applied; meanwhile, with the consideration of the non-zero mean α, variance σ and skewness ε. According to the results, comparing with the Newtonian fluids, the tilted bearing lubricated with magnetic ferrofluid has the higher built-up pressure distribution and load-carrying capacities. As the non-zero mean α of the surface roughness increases, the responding time decreases. On the other hand, increases the variation σ, decreases the responding time in longitudinal surface roughness; whereas, the transverse type has the inverse trend of responding time when variation increases.

Effect of surface roughness and subsurface damage on grazing-incidence x-ray scattering and specular reflectance

1998 ◽  
Vol 37 (22) ◽  
pp. 5239 ◽  
Author(s):  
Gyanendra S. Lodha ◽  
Koujun Yamashita ◽  
Hideyo Kunieda ◽  
Yuzuru Tawara ◽  
Jin Yu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Grazing Incidence ◽  
Subsurface Damage ◽  
X Ray ◽  
Specular Reflectance ◽  
X Ray Scattering ◽  
Effect Of Surface ◽  
Ray Scattering
Sign in / Sign up

Export Citation Format

Share Document