Measurement of aggregate breakdown under rain - Comparison with tests of water stability and relationships with field measurements of infiltration

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 701 ◽  
Author(s):  
RJ Loch ◽  
JL Foley
Keyword(s):  
Surface Layer ◽  
Soil Surface ◽  
High Energy ◽  
Alternative Methods ◽  
Data Set ◽  
Swelling Soils ◽  
Infiltration Rates ◽  
Aggregate Breakdown ◽  
Eastern Australia ◽  
Wide Range

This paper reports comparisons between aggregate breakdown on wetting by rainfall with breakdown measured by a range of alternative methods. It also reports correlations between measured breakdown and steady infiltration rates of simulated rain of high and low energy, and hydraulic conductivities of surface seal layers formed under high energy rain. A wide range of soils in eastern Australia were studied. Highly significant correlations were found between measurements of aggregate breakdown to < 125 �m caused by rainfall wetting and both steady infiltration rates and hydraulic conductivities. Significant, but poorer correlations were found between steady infiltration rates and breakdown resulting from immersion wetting. Deletion of swelling soils from the data set greatly improved correlations between steady infiltration rates of high energy rain and breakdown measured by both immersion and tension wetting, showing that these methods of wetting ace particularly inappropriate for swelling soils. No correlation was found between infiltration rates and measured clay dispersion. Different relationships between the proportion of particles (%) < 125 �m at the soil surface (P125) and steady infiltration rates of low and high energy rain indicated that compaction of the soil surface layer, rather than increased aggregate breakdown, is a major cause of surface sealing by raindrop impacts. Measurements of fall cone penetration confirmed that drop impacts had compacted the surface layer. Suctions across the surface seal were related to P125 in that layer, and the relationship obtained was used in calculating hydraulic conductivities. The results confirm that measurement of aggregate breakdown under rainfall wetting produces results of much greater relevance to soil behaviour under field conditions than do tests based on immersion and tension wetting.

scholarly journals Calibration and performance of the NIKA2 camera at the IRAM 30-m Telescope

2020 ◽  
Vol 637 ◽  
pp. A71 ◽  
Author(s):  
L. Perotto ◽  
N. Ponthieu ◽  
J. F. Macías-Pérez ◽  
R. Adam ◽  
P. Ade ◽  
...  
Keyword(s):  
Flux Density ◽  
Calibration Method ◽  
Beam Pattern ◽  
Alternative Methods ◽  
Dual Band ◽  
Main Beam ◽  
Kinetic Inductance ◽  
Baseline Method ◽  
Data Set ◽  
Wide Range

Context. NIKA2 is a dual-band millimetre continuum camera of 2 900 kinetic inductance detectors, operating at 150 and 260 GHz, installed at the IRAM 30-m telescope in Spain. Open to the scientific community since October 2017, NIKA2 will provide key observations for the next decade to address a wide range of open questions in astrophysics and cosmology. Aims. Our aim is to present the calibration method and the performance assessment of NIKA2 after one year of observation. Methods. We used a large data set acquired between January 2017 and February 2018 including observations of primary and secondary calibrators and faint sources that span the whole range of observing elevations and atmospheric conditions encountered by the IRAM 30-m telescope. This allowed us to test the stability of the performance parameters against time evolution and observing conditions. We describe a standard calibration method, referred to as the “Baseline” method, to translate raw data into flux density measurements. This includes the determination of the detector positions in the sky, the selection of the detectors, the measurement of the beam pattern, the estimation of the atmospheric opacity, the calibration of absolute flux density scale, the flat fielding, and the photometry. We assessed the robustness of the performance results using the Baseline method against systematic effects by comparing results using alternative methods. Results. We report an instantaneous field of view of 6.5′ in diameter, filled with an average fraction of 84%, and 90% of valid detectors at 150 and 260 GHz, respectively. The beam pattern is characterised by a FWHM of 17.6″ ± 0.1″ and 11.1″ ± 0.2″, and a main-beam efficiency of 47%±3%, and 64%±3% at 150 and 260 GHz, respectively. The point-source rms calibration uncertainties are about 3% at 150 GHz and 6% at 260 GHz. This demonstrates the accuracy of the methods that we deployed to correct for atmospheric attenuation. The absolute calibration uncertainties are of 5%, and the systematic calibration uncertainties evaluated at the IRAM 30-m reference Winter observing conditions are below 1% in both channels. The noise equivalent flux density at 150 and 260 GHz are of 9 ± 1 mJy s1/2 and 30 ± 3 mJy s1/2. This state-of-the-art performance confers NIKA2 with mapping speeds of 1388 ± 174 and 111 ± 11 arcmin2 mJy−2 h−1 at 150 and 260 GHz. Conclusions. With these unique capabilities of fast dual-band mapping at high (better that 18″) angular resolution, NIKA2 is providing an unprecedented view of the millimetre Universe.

scholarly journals Capture of overland flow by a tree belt on a pastured hillslope in south-eastern Australia

Soil Research ◽  
2006 ◽  
Vol 44 (2) ◽  
pp. 117 ◽  
Author(s):  
T. W. Ellis ◽  
S. Leguédois ◽  
P. B. Hairsine ◽  
D. J. Tongway
Keyword(s):  
Water Supply ◽  
Overland Flow ◽  
Soil Surface ◽  
Rainfall Events ◽  
Surface Conditions ◽  
Infiltration Rates ◽  
Excess Water ◽  
Overland Flows ◽  
Eastern Australia ◽  
Tree Litter

We describe a rainfall simulator experiment designed to measure the capture, by a fenced tree belt, of excess water generated as Hortonian flow from a pasture slope. Three rainfall events (48, 49, and 75 mm/h for 13, 30, and 30 min, respectively) were applied, of which 15%, 29%, and 44%, respectively, ran off and drained onto the tree belt. The tree belt captured 100%, 32–68%, and 0–28% of the runoff from the 3 events, respectively. These captured runoff volumes represented 31–39%, 22–45%, and 0–29% increases in water supply to the trees, in addition to incident rainfall. Infiltration rates within the tree belt were up to 46% higher than in the pasture zone. This higher infiltration was mainly attributed to better soil surface conditions in the absence of stock and a 50-mm layer of tree litter. Overland flows within the tree belt formed tree litter into microterraces, which spread and slowed flows and allowed greater time for infiltration.

scholarly journals Determination of qualitative working indices of harrows with elastic fangs

2021 ◽  
Vol 286 ◽  
pp. 03006
Author(s):  
Dan Cujbescu ◽  
Gheorghe Matei ◽  
Dimitar Kehayov ◽  
Atanas Atanasov
Keyword(s):  
Surface Layer ◽  
Field Tests ◽  
Soil Surface ◽  
Modern Agriculture ◽  
Damage Degree ◽  
Wide Range ◽  
Energy Indices ◽  
Qualitative Work ◽  
Agricultural Machines

In modern agriculture, grinding, levelling, loosening the soil surface layer and weed destruction, with application in the vegetable and technical crops sector, are carried out by a wide range of agricultural machines generically called harrows. These operations must be carried out by splitting on the natural lines of cohesion and not by hitting, cutting, compressing, breaking, when everything turns to dust. The paper presents the field tests for a harrow with elastic fangs in order to determine the following qualitative work indices: degree of soil grinding, degree of plant damage, degree of weed destruction, degree of levelling, working depth and operating energy indices for the maintenance of corn and sunflower crops.

scholarly journals Water Hummer Technology for Soil Destruction on Dredgers

2020 ◽  
Vol 9 (3) ◽  
pp. 3570-3576
Keyword(s):  
Surface Layer ◽  
Dynamic Equilibrium ◽  
Technical Problem ◽  
Soil Layer ◽  
Soil Surface ◽  
High Energy ◽  
Water Hammer ◽  
Mechanical Equipment ◽  
Compacted Soil ◽  
Ambient Temperatures

The present investigation aims to propose a solution of the problem which is connected with slurry processing during the dredger’s operation under difficult conditions. On dredgers, depending on the degree of air dryness or low ambient temperatures very often arises technical problem that creates difficulties for the crew. It is connected with the fact that soil surface layer is very dense. It is very difficult to dredge the soil during extraction under water surface or unloading from the hold of a vessel at low ambient temperatures. The top layer of the very soil is characterized by a high degree of compaction and can be destroyed in two ways only. The first way is to use very powerful mechanical equipment (percussion mechanisms, vibration equipment, etc.). This method is associated with high energy spending and its use on a vessel is technically difficult. The second way is to use the soil cutting process with the use of mechanical cutters. Dredger’s operation with the use of milling equipment is always characterized by the fact that during soil mechanical treatment there is always occurs breakage of the cutter teeth or rapid wear of the cutting surfaces. A similar problem occurs when sandy or clay soil is extracted under water, which is compacted by its properties. In investigation a non-trivial solution was used to solve the problem of destruction of the compacted soil layer during the operation of the dredger. It was proposed to use the hydrodynamic method based on water hammer as the main mechanism for the destruction of compacted soil. As a result of the interaction of the compacted soil layer and high pressurized directed water jets, good performance of the dredger can be achieved. The two-dimensional mechanism of destruction of the compacted soil layer can be described by the condition of dynamic equilibrium of the three main flows - the jet, which flows from the conical nozzle and two flows along the soil surface. For these streams, a reactive force evaluation has been performed. Destructive jets can be generated by standard marine pumps in combination with the use of water hammer. Based on the results of the experiments, it was found that the qualitative destruction of the surface layer of compacted soil occurs using two or three phases of hydraulic water hummer.

scholarly journals Predicting Differences in Model Parameters with Individual Parameter Contribution Regression Using the R Package Ipcr

Psych ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 360-385
Author(s):  
Manuel Arnold ◽  
Andreas M. Brandmaier ◽  
Manuel C. Voelkle
Keyword(s):  
False Negative ◽  
R Package ◽  
Parametric Models ◽  
Alternative Methods ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Modeling Framework ◽  
Data Set ◽  
Individual Parameter ◽  
Wide Range

Unmodeled differences between individuals or groups can bias parameter estimates and may lead to false-positive or false-negative findings. Such instances of heterogeneity can often be detected and predicted with additional covariates. However, predicting differences with covariates can be challenging or even infeasible, depending on the modeling framework and type of parameter. Here, we demonstrate how the individual parameter contribution (IPC) regression framework, as implemented in the R package ipcr, can be leveraged to predict differences in any parameter across a wide range of parametric models. First and foremost, IPC regression is an exploratory analysis technique to determine if and how the parameters of a fitted model vary as a linear function of covariates. After introducing the theoretical foundation of IPC regression, we use an empirical data set to demonstrate how parameter differences in a structural equation model can be predicted with the ipcr package. Then, we analyze the performance of IPC regression in comparison to alternative methods for modeling parameter heterogeneity in a Monte Carlo simulation.

Effects of fallow management and cropping history on aggregate breakdown under rainfall wetting for a range of Queensland soils

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 1125 ◽  
Author(s):  
RJ Loch
Keyword(s):  
Management Practices ◽  
Crop Residues ◽  
Size Fraction ◽  
Bare Soil ◽  
High Energy ◽  
Low Energy ◽  
Infiltration Rates ◽  
Fallow Management ◽  
Aggregate Breakdown ◽  
Improved Stability

This paper reports changes in stability of soils to wetting under a range of fallow management/cropping treatments for eight experiment sites in Queensland. Because of its greater relevance to dryland soils, and its better correlation with field soil behaviour, wetting with high energy rain (HER) was used to wet samples and cause aggregate breakdown. The water-stable size fraction considered was that <0.125 mm, with the proportion of particles <0.125 mm referred to as P125. To study interactions between wetting method and tillage management, several other wetting methods were applied to some or all of the eight soils. These other methods were immersion (IMM), wetting by rainfall of low energy (LER) or under tension (TENS). Where fallow management treatments significantly reduced P125 under HER wetting, those reductions were generally small, and likely to increase steady infiltration rates of high energy rain into bare soil by only 2-6 mm h-1. In contrast, steady infiltration rates could be increased by 15-42 mm h-1 if those same soil surfaces were completely covered by stubble so that they received low energy rain. At least under Queensland conditions, retention of crop residues to protect soils from drop impact is therefore likely to be of much greater importance in improving water storage during fallows than any improvement in soil aggregation under 'improved' fallow management practices. Effects of fallow management and cropping history on P125 under HER varied across the sites. Three out of four virgin soils were more stable than corresponding cropped soils; stubble retention improved stability to HER wetting on three out of four sites where it was tested, and direct drill or reductions in tillage frequency improved stability at two out of eight sites. IMM showed responses to treatments that, for some soils, differed greatly from those obtained using HER. Neither LER nor TENS appeared useful, as LER gave occasional inconsistent results, and TENS caused little aggregate breakdown for most soils.

scholarly journals An assessment of the performance of global rainfall estimates without ground-based observations

2017 ◽  
Vol 21 (9) ◽  
pp. 4347-4361 ◽  
Author(s):  
Christian Massari ◽  
Wade Crow ◽  
Luca Brocca
Keyword(s):  
High Performance ◽  
Daily Rainfall ◽  
Global Scale ◽  
Data Sets ◽  
Data Set ◽  
Reanalysis Product ◽  
Eastern Australia ◽  
Wide Range ◽  
Satellite Rainfall ◽  
Rainfall Estimates

Abstract. Satellite-based rainfall estimates over land have great potential for a wide range of applications, but their validation is challenging due to the scarcity of ground-based observations of rainfall in many areas of the planet. Recent studies have suggested the use of triple collocation (TC) to characterize uncertainties associated with rainfall estimates by using three collocated rainfall products. However, TC requires the simultaneous availability of three products with mutually uncorrelated errors, a requirement which is difficult to satisfy with current global precipitation data sets. In this study, a recently developed method for rainfall estimation from soil moisture observations, SM2RAIN, is demonstrated to facilitate the accurate application of TC within triplets containing two state-of-the-art satellite rainfall estimates and a reanalysis product. The validity of different TC assumptions are indirectly tested via a high-quality ground rainfall product over the contiguous United States (CONUS), showing that SM2RAIN can provide a truly independent source of rainfall accumulation information which uniquely satisfies the assumptions underlying TC. On this basis, TC is applied with SM2RAIN on a global scale in an optimal configuration to calculate, for the first time, reliable global correlations (vs. an unknown truth) of the aforementioned products without using a ground benchmark data set. The analysis is carried out during the period 2007–2012 using daily rainfall accumulation products obtained at 1° × 1° spatial resolution. Results convey the relatively high performance of the satellite rainfall estimates in eastern North and South America, southern Africa, southern and eastern Asia, eastern Australia, and southern Europe, as well as complementary performances between the reanalysis product and SM2RAIN, with the first performing reasonably well in the Northern Hemisphere and the second providing very good performance in the Southern Hemisphere. The methodology presented in this study can be used to identify the best rainfall product for hydrologic models with sparsely gauged areas and provide the basis for an optimal integration among different rainfall products.

Simulation of an experiment on detecting ultra-high-energy particles with regard to the structure of the lunar soil surface layer

2010 ◽  
Vol 55 (1) ◽  
pp. 98-103 ◽  
Author(s):  
G. A. Gusev ◽  
B. N. Lomonosov ◽  
N. G. Polukhina ◽  
V. A. Ryabov ◽  
V. A. Tsarev ◽  
...  
Keyword(s):  
Surface Layer ◽  
Soil Surface ◽  
Lunar Soil ◽  
High Energy ◽  
Ultra High Energy ◽  
High Energy Particles

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Compact back-scattered electrons' energy analyzer for standard SEM

1994 ◽  
Vol 52 ◽  
pp. 488-489
Author(s):  
S. Likharev ◽  
A. Kramarenko ◽  
V. Vybornov
Keyword(s):  
Depth Resolution ◽  
High Energy ◽  
Primary Beam ◽  
Layer By Layer ◽  
Energy Analyzer ◽  
High Energy Part ◽  
Small Window ◽  
Energy Part ◽  
Wide Range ◽  
High Voltage Supply

At present time the interest is growing considerably for theoretical and experimental analysis of back-scattered electrons (BSE) energy spectra. It was discovered that a special angle and energy nitration of BSE flow could be used for increasing a spatial resolution of BSE mode, sample topography investigations and for layer-by layer visualizing of a depth structure. In the last case it was shown theoretically that in order to obtain suitable depth resolution it is necessary to select a part of BSE flow with the directions of velocities close to inverse to the primary beam and energies within a small window in the high-energy part of the whole spectrum.A wide range of such devices has been developed earlier, but all of them have considerable demerit: they can hardly be used with a standard SEM due to the necessity of sufficient SEM modifications like installation of large accessories in or out SEM chamber, mounting of specialized detector systems, input wires for high voltage supply, screening a primary beam from additional electromagnetic field, etc. In this report we present a new scheme of a compact BSE energy analyzer that is free of imperfections mentioned above.

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