Surface Microreliefs Research Articles

Surface microrelief induced by tillage management alters the pathway and composition of dissolved organic matter exports from soils to runoff during rainfall

Rainfall-runoff process mobilizes considerable dissolved organic matter (DOM) from soils to aquatic systems via surface and sub-surface flow pathways. Microrelief induced by tillage management can alter this flow partitioning and thus likely affect the associated pathway and composition of DOM exports during rainfall. This study conducted rainfall simulation experiments, combined with three-dimensional fluorescence spectra analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) technology, to explore the effects of different surface microreliefs treatments on the quantity and composition of DOM exports at a plot scale. Four typical microrelief treatments (i.e., contour tillage (CP), longitudinal tillage (LP), artificial digging tillage (AP), and flat tillage (CK, as control)) were selected. Results showed that ratios of surface to sub-surface flow volume under four treatments were in order of LP (193:1)>CK (73:1)>AP (4.5:1)>CP (0.5:1). DOM concentrations in sub-surface flow (13.37∼33.50 mg L-1) were 7∼18 times of that in surface flow (0.03∼4.56 mg L-1). The total export fluxes of DOM were 134, 139, 563, and 1214 mg m-2 at LP, CK, AP, and CP treatments, respectively, with proportions of 8%, 17%, 82%, and 98% via sub-surface flow. Compared to surface flow, DOM molecular composition in sub-surface flow showed a significant feature of higher oxygen to carbon ratio, higher molecular weight, and lower hydrogen to carbon ratio. The findings indicated that microrelief with higher surface storage capacity tends to favor a large flux of DOM export, primarily via sub-surface flow, which might significantly affect the DOM cycling in the receiving aquatic ecosystems.

The relationship of the geometric parameters of the surface with its properties (optical, emission, tribological)

This article presents the results of the possibility of manufacturing different types of microstructures. Special surface microreliefs have been created to solve a number of important problems related to the functional properties of the object surface and its relationship with the environment.

Control of Laminar-Turbulent Transition on a Swept Wing Using Surface Microreliefs

The possibility of laminarization of flow around a swept wing using surface microreliefs in the form of riblets and separate plates (winglets) set at an angle to external streamlines is theoretically investigated. This relief is shown to reduce the crossflow velocity in the boundary layer due to a change in the direction of the near-wall streamlines. On the basis of very simple models based on an analysis of the relief period-averaged boundary layer flow an increase in the Reynolds number of laminar-turbulent transition obtained using the microrelief is estimated. The reasonable surface relief parameters for experimentally investigating the effectiveness of the proposed technique of controlling laminar-turbulent transition are determined.

The role of surface microreliefs in influencing splash erosion: A laboratory study

Wu J., Zhao L., Wu F., Li Z. (2016): The role of surface microreliefs in influencing splash erosion: A laboratory study. Soil & Water Res., 11: 83–89. The detachment and transport of soil particles from soil mass are important effects of falling raindrops on soil erosion during rainfall. The objective of this study was to determine whether soil microrelief affects the detachability and transportability of soil particles by raindrop splash. Experimental microreliefs were manually simulated by two tillage practices: shallow hoeing, contour chisel plowing, and a smooth slope served as control treatment. The experiment included three simulated rainfall intensities (1.0, 1.5, and 2.0 mm/min). A splash board was used to collect sediment splashed upslope as well as that splashed downslope. Results show that microrelief has a positive effect on detachment rate (DRt) and has a negative effect on net downslope movement rate (SPnet). With the exception of DRt of which hoe treatment was less than smooth at the rainfall of 1.0 mm/min intensity, DRt of hoe and chisel treatments were twice as high as that of smooth to other treatments. For all treatments, SPnet of hoe and chisel treatments were less than half of smooth. Regression analysis showed that DRt change with increasing rainfall intensity could be described by a power function for all treatments. The change of SPnet could be described by a logarithmic function for hoe and chisel treatments, while the change of SPnet of the smooth treatment could not be described by a logarithmic function. Statistical results suggest that DRt was significantly influenced by rainfall intensity, while SPnet was not. Conversely, SPnet was significantly influenced by soil microrelief, while DRt was not.

A surface microrelief on the leaves of Glossophyllum florinii (?Ginkgoales) from the Upper Triassic of Lunz, Austria

The cuticles of many extant seed plants display distinct surface microreliefs, which represent adaptations to certain habitat conditions or mechanical defences against herbivores and phytopathogenic microorganisms. Although microreliefs have variously been noted in fossil cuticles, hypotheses relating to the effectiveness of these structures in fossil plants have not been advanced to date. A surface microrelief composed of longitudinally orientated idiocuticular striae occurs on the leaves of the enigmatic Carnian (Late Triassic) gymnosperm (?ginkgophyte) Glossophyllum florinii Krausel from the Northern Calcareous Alps of lower Austria. Most striae originate from the tips of the papillae on the stomatal subsidiary cells. The G. florinii surface microrelief may have (1) reduced leaf wettability, (2) produced or enhanced the self-cleaning effect of the leaf, (3) prevented the formation of a water film on the leaf surface, and/or (4) mechanically stabilized the leaf. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153, 87–95.

Using substrates with various surface microreliefs in optoelectronics and information-display devices

This paper discusses various designs of displays with elements on whose surface there is regular or irregular microrelief. The effect of the parameters of the microrelief (the period, depth, shape, and refractive index) on the characteristics of liquid-crystal and LED displays is investigated. Examples are given of structures with microlens relief for creating group-use screens with the possibility of forming an autostereoscopic image and ZBD (zenithal bistable device) displays with microrelief and homeotropic surface orientation of the liquid crystals (LCs) for the implementation of bistable or multistable switching of the optical response of an LC cell. In conclusion, modern methods are considered for shaping surface microrelief, and methods of determining the optical characteristics of the substrates of such displays are discussed. © 2005 Optical Society of America

Surface Microreliefs and Voltage–Current Characteristics of Gold Electrodes and Modified Thick-Film Graphite-Containing Electrodes

The surface microreliefs and voltage–current characteristics of gold electrodes and modified thick-film graphite-containing electrodes were studied. The relationship between the formation of an analytical signal of mercury(II) and the surface microrelief was determined. It was found that the surface of a modified graphite-containing electrode is a self-organizing ensemble of microelectrodes.

Estimation of surface runoff and water-covered area during filling of surface microrelief depressions

During the filling of surface microrelief depressions the precipitation excess (precipitation minus infiltration and interception) is divided between surface storage and runoff, i.e. runoff starts before the surface depressions are filled. Information on the division of precipitation excess is needed for modelling surface runoff during the filling of surface depressions. Furthermore, information on the surface of the area covered with water is needed for calculating infiltration of water stored in soil surface depressions. Thirty-two soil surface microreliefs were determined in Danish erosion study plots. The slope was c. 10% for all plots. Data were treated initially by removing the slope, after which 20 ‘artificial’ slopes (1–20%) were introduced producing 640 new data sets. Runoff during filling of the microrelief storage was calculated for each of the 640 data sets using a model developed for calculating surface storage and runoff from grid elevation measurements. Runoff started immediately after the first addition of water for all data sets. On a field scale, however, runoff has to travel some distance as overland flow and storage in smaller and larger depressions below the runoff initiation point must be taken into consideration. The runoff increases by intermittent steps. Whenever a depression starts to overflow to the border of the plot, the runoff jumps accordingly. In spite of the jumps, the distribution between surface storage and runoff was closely related to the quotient between precipitation excess and depression storage capacity. Surface area covered with water was exponentially related to the amount of water stored in surface depressions. Models for calculating surface storage and runoff from grid elevation measurements are cumbersome and require time-consuming measurements of the soil surface microrelief. Therefore, estimation from roughness indices requiring fewer measurements is desirable. New improved equations for such estimations are suggested. Copyright © 2000 John Wiley & Sons, Ltd.

Roughness indices for estimation of depression storage capacity of tilled soil surfaces

Information on the depression storage capacity (DSC) of soil surfaces is needed for modelling surface runoff and erosion. However, time-consuming measurements of the soil surface microrelief in a two-dimensional grid are necessary to obtain accurate estimates. Therefore, estimation of DSC from roughness indices requiring fewer measurements is desirable. In this study a new simple and physically based roughness index was developed and tested. Thirty-two soil surface microreliefs were determined in Danish erosion study plots on two sandy loam soil types, Humic Acrosol and Haplic Luvisol according to the FAO soil classification. The soil treatments were: cultivated up-and-down the slope (black fallow), mouldboard ploughed up-and-down the slope, winter wheat ( Triticum aestivum L.) drilled up-and-down the slope and winter wheat drilled across the slope. The slope was ca. 10% for all plots. Data were treated initially by removing the slope after which 20 artificial slopes (1–20%) were introduced producing 640 data sets. The DSC was calculated for each data set and a number of roughness indices were related to the calculated DSC. The best correlation to DSC was obtained by the newly developed index, mean upslope depression, MUD ( R 2 = 0.86), followed by the geostatistically based limiting elevation difference, LD, and limiting slope, LS ( R 2 = 0.76), and some statistically based parameters as standard deviation adjusted for oriented roughness up-and-down the slope ( R 2 = 0.76), random roughness, RR ( R 2 = 0.67), and standard deviation adjusted for oriented roughness both up-and-down and across the slope ( R 2 = 0.62). Furthermore, MUD appeared to give less biased estimates than other indices, which overestimated small DSC-values and underestimated larger DSC-values. Calculations showed that the MUD index required relatively few measurements. MUD based on less than 200 surface elevation readings gave a good prediction ( R 2 > 0.7) of DSC of tilled soil surfaces.

Spontaneous anisotropic etching of the InP(100) surface in concentrated hydrochloric and sulfuric acids

Spontaneous one-step anisotropic etching of InP(100) in concentrated hydrochloric and sulfuric acids is reported. Within certain temperature and time intervals the formation of surface microreliefs occurs of asterisk-like (for H 2SO 4), grating-like (for HCl) and parquet-like (H 2SO 4-HCl mixture with H 2SO 4: HCl of 1:1) morphology. The kinetics of the etching are discussed. Estimation of the activation energies gives 8.5 kcal mol −1, 20.0 kcal mol −1 and 7.0 kcal mol −1 respectively, thus demonstrating that the etching occurs in the kinetic region. The formation of the grating-like microrelief is assumed to be suitable for producing antireflecting InP surfaces for solar cells.

Effect of rainfall on the surface micro-relief of tilled soil

Abstract Surface micro-reliefs after four different tillage treatments were measured with a relief meter. Measurements were taken at the time of tillage and on four successive dates. The relief measurements were used to calculate the autocorrelation functions, the power spectra, and the distributions of surface slopes. Changes in parameters of these functions are related to estimates of the cumulative rainfall kinetic energy between the readings and the tensile yield stress of aggregates from the tilled soil. The effect of rainfall was to reduce the roughness to a given proportion in a time which was independent of the initial roughness of the surface, and hence independent of the type of implement used.