Fresnel calculation of holograms for micrometer-scale material structuring on substrates with complex surface topography

2017 ◽  
Author(s):  
Alexander Kabardiadi-Virkovski ◽  
Tobias Baselt ◽  
Andrés Fabián Lasagni ◽  
Peter Hartmann
Keyword(s):  
Surface Topography ◽  
Complex Surface ◽  
Micrometer Scale

Regional-scale groundwater flow in a Canadian Shield setting

2009 ◽  
Vol 46 (7) ◽  
pp. 813-827 ◽  
Author(s):  
Jonathan F. Sykes ◽  
Stefano D. Normani ◽  
Mark R. Jensen ◽  
Edward A. Sudicky
Keyword(s):  
Groundwater Flow ◽  
Surface Topography ◽  
Regional Scale ◽  
Three Dimensional ◽  
Complex Surface ◽  
Crystalline Rock ◽  
Canadian Shield ◽  
Water Drainage ◽  
Distribution Models ◽  
Matrix Permeability

A three-dimensional numerical analysis of a 5734 km2 watershed situated in the Canadian Shield has been conducted to illustrate aspects of regional-scale groundwater flow in a crystalline rock setting. An essential requirement of the analysis is the preservation and accurate description of the complex topography, surface water drainage network, groundwater salinity distribution, and permeability distributions. The postglacial evolution of the groundwater flow system was investigated using the finite difference model SWIFT-III. Robustness was assessed by exploring the sensitivity of groundwater flow to topography, variable matrix permeability distribution models, pore-water salinity, and the dissipation of elevated initial pore pressures that result from ice that overlaid the watershed in the last glacial period. Groundwater flow analyses indicate that freshwater heads in all model layers are highly correlated with the complex surface topography such that the transition from zones of groundwater recharge to zones of discharge occurs over distances that can be relatively short. Shallow flow to a depth of tens of metres dominates the overall water balance, and the length of flow paths is relatively short. The analyses of this study indicate that the flow in deeper rock is not regional but rather is a subdued reflection of the local-scale surface topography.

scholarly journals Amplification of elastic waves due to a point source in the presence of complex surface topography

2001 ◽  
Vol 79 (18) ◽  
pp. 1697-1712 ◽  
Author(s):  
António Tadeu ◽  
Paulo Santos ◽  
Julieta António
Keyword(s):  
Point Source ◽  
Surface Topography ◽  
Elastic Waves ◽  
Complex Surface

scholarly journals Distribution and characteristics of microplastics in the sediments of Poyang Lake, China

2019 ◽  
Vol 79 (10) ◽  
pp. 1868-1877 ◽  
Author(s):  
Shuli Liu ◽  
Minfei Jian ◽  
Longyin Zhou ◽  
Wenhua Li
Keyword(s):  
Surface Topography ◽  
Strong Evidence ◽  
Aquatic Environment ◽  
Poyang Lake ◽  
Complex Surface ◽  
Field Observations ◽  
Porous Structures ◽  
Sediment Samples ◽  
X Ray ◽  
Extensive Damage

Abstract Microplastics are considered to be a widespread environmental contaminant, posing a serious threat to the aquatic environment. We addressed this issue based on field observations and laboratory analysis of samples from Poyang Lake. We collected sediment samples from 10 sites across Poyang Lake during 2017. Data were analyzed by one-way analysis of variance (ANOVA). Results showed that the abundance of microplastics ranged from 11 to 3,153 items/kg dw in the sediment samples. Except at Nanjishan, the amount of microplastics in different periods decreased in the order: December > April > July. Microplastics with a size <1 mm were the most abundant fraction in sediments, reaching over 50%. Observations under microscope revealed four types of microplastics in Poyang Lake: fragments, films, foams and fibers. Fragments were more common in sediments. Microplastics have complex surface topography, typically including rough surfaces, porous structures, cracks and extensive damage. Energy dispersive X-ray analysis indicated that most microplastics contained Si, Na, Ca, Cl and Al. Overall, the results provided strong evidence of high levels of microplastics in Poyang Lake, suggested that the microplastics pollution status in Poyang Lake should continue to be monitored.

scholarly journals Modelling and analysis of surface topography generated in end milling process

2021 ◽  
Author(s):  
ruihu zhou ◽  
Chen Qilin
Keyword(s):  
Surface Topography ◽  
End Milling ◽  
Complex Surface ◽  
Cutting Parameters ◽  
Milling Process ◽  
Surface Geometry ◽  
Experimental Conditions ◽  
Workpiece Surface ◽  
Proposed Model ◽  
Set Up

Abstract The surface topography of workpiece plays an important role in the performance and service life of workpiece. Complex surface parts are widely used in shipbuilding, aerospace and other industries. At present, the study of milling surface topography is mainly on 3-axis milling. A prediction model of milling surface topography is proposed, which can obtain the machined workpiece surface topography and roughness directly from cutting parameters, cutter location file and workpiece surface geometry. The effects of cutting parameters on surface roughness is discussed. Different milling experimental conditions are set up to validate the proposed model. This method can be used to analyze the surface topography of milling, and further to optimize the cutting parameters to improve the surface quality.

scholarly journals Modeling and Analysis of Micro Surface Topography from Ball-End Milling in a Trochoidal Milling Mode

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1203
Author(s):  
Yongheng Dong ◽  
Shujuan Li ◽  
Qian Zhang ◽  
Pengyang Li ◽  
Zhen Jia ◽  
...  
Keyword(s):  
Surface Topography ◽  
High Speed ◽  
End Milling ◽  
Complex Surface ◽  
Summation Method ◽  
Time Step ◽  
Ball End Milling ◽  
Map Algorithm ◽  
Trochoidal Milling ◽  
Grid Nodes

The trochoidal milling mode is widely used in high-speed machining, and due to good adaptability and flexible posture adjustment, ball-end milling cutters are conducive to complex surface machining with this mode. However, the processes of material removal and formation of machined micro surfaces are very difficult to describe as the profile of cutter teeth is complex and the trajectory direction changes continuously during the trochoidal milling process. A modeling method for the generation of micro surface topography of ball-end milling in the trochoidal milling mode is put forward. In this method, the locus equation of each cutter tooth is established based on the principle of homogeneous coordinate transformation, after which a Z-MAP algorithm is designed to simulate the micro surface topography. The Z-MAP algorithm can quickly obtain the part grid nodes potentially swept by the cutter tooth within a unit time step through the establishment of servo rectangular encirclement and instantaneous sweeping quadrilateral of the element of cutter teeth; the part grid nodes actually swept are further determined through an angle summation method, and the height coordinate is calculated with the method of linear interpolation according to Taylor’s formula of multivariate functions. Experiments showed that the micro surface topography resulting from ball-end milling in the trochoidal milling mode had high consistency with the simulation, which indicates that the proposed method can predict micro surface topography in practical manufacturing. In addition, a comparison of micro surface topography between trochoidal milling and ordinary straight-linear milling was conducted, and the results showed that the former was overall superior to the latter in resulting characteristics. Based on this conclusion, the influences of cutting parameters of ball-end trochoidal milling on surface characteristics, particularly amplitude and function, were analyzed according to the simulated micro surface topography data.

Characteristics of Surface Topography and Static Friction on Scraped Surface Slideway—Part 1

1980 ◽  
Vol 102 (2) ◽  
pp. 97-103 ◽  
Author(s):  
S. Kato ◽  
E. Marui ◽  
A. Kobayashi ◽  
T. Matsubayashi
Keyword(s):  
Surface Topography ◽  
Boundary Lubrication ◽  
Complex Surface ◽  
Static Friction ◽  
Friction Characteristics ◽  
Depth Direction ◽  
Ellipsoidal Shape

The complex surface topography of a scraped surface is studied quantitatively. The scraped surfaces are composed of the surface elements which are formed by each scraping operation, distribute in the depth direction, and have many asperities. Based on this model, the microscopic contacting problem between two scraped surfaces and static frictional characteristics are investigated under boundary lubrication. As a result, it is clarified that the ellipsoidal shape of the asperity tip of scraping surface may be regarded as optimal from the point of static friction, and the static friction characteristics are considerably influenced by the scraping directions.

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