Quantifying the heterogeneity of soil compaction, physical soil properties and soil moisture across multiple spatial scales

Science.gov (United States)

Coates, Victoria; Pattison, Ian; Sander, Graham

2016-04-01

England's rural landscape is dominated by pastoral agriculture, with 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Since the Second World War the intensification of agriculture has resulted in greater levels of soil compaction, associated with higher stocking densities in fields. Locally compaction has led to loss of soil storage and an increased in levels of ponding in fields. At the catchment scale soil compaction has been hypothesised to contribute to increased flood risk. Previous research (Pattison, 2011) on a 40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. However, at the catchment scale there is likely to be a significant amount of variability in compaction levels within and between fields, due to multiple controlling factors. This research focusses in on one specific type of land use (permanent pasture with cattle grazing) and areas of activity within the field (feeding area, field gate, tree shelter, open field area). The aim was to determine if the soil characteristics and soil compaction levels are homogeneous in the four areas of the field. Also, to determine if these levels stayed the same over the course of the year, or if there were differences at the end of the dry (October) and wet (April) periods. Field experiments were conducted in the River Skell catchment, in Yorkshire, UK, which has an area of 120km2. The dynamic cone penetrometer was used to determine the structural properties of the soil, soil samples were collected to assess the bulk density, organic matter content and permeability in the laboratory and the Hydrosense II was used to determine the soil moisture content in the topsoil. Penetration results show that the tree shelter is the most compacted and the open field area

A soil mechanics approach to study soil compaction and traffic effect on the preconsolidation pressure of tropical soils

International Nuclear Information System (INIS)

Dias Junior, Moacir de Souza

2004-01-01

Several researchers have already demonstrated the causes and the effects of soil compaction. These studies showed that the soil compaction is a limiting factor in the agricultural production. The attributes of the soil conventionally monitored has not been capable to quantify the load support capacity of the soil, not allowing to foresee the levels of pressures that can be applied to the soils at different moisture conditions without additional soil compaction (structure degradation) happens. The researches done in the soil compressive behaviour of some tropical soils indicate that the pre-compression stress may be used as an alternative measure of the load support capacity and as a quantitative indicator of the structure sustainability of the tropical soils

Soil compaction: Evaluation of stress transmission and resulting soil structure

Science.gov (United States)

Naveed, Muhammad; Schjønning, Per; Keller, Thomas; Lamande, Mathieu

2016-04-01

Accurate estimation of stress transmission and resultant deformation in soil profiles is a prerequisite for the development of predictive models and decision support tools for preventing soil compaction. Numerous studies have been carried out on the effects of soil compaction, whilst relatively few studies have focused on the cause (mode of stress transmission in the soil). We have coupled both cause and effects together in the present study by carrying out partially confined compression tests on (1) wet aggregates, (2) air dry aggregates, and (3) intact soils to quantify stress transmission and compaction-resulted soil structure at the same time. Stress transmission was quantified using both X-ray CT and Tactilus sensor mat, and soil-pore structure was quantified using X-ray CT. Our results imply that stress transmission through soil highly depends on the magnitude of applied load and aggregate strength. As soon as the applied load is lower than the aggregate strength, the mode of stress transmission is discrete as stresses were mainly transmitted through chain of aggregates. With increasing applied load soil aggregates start deforming that transformed heterogeneous soil into homogenous, as a result stress transmission mode was shifted from discrete towards more like a continuum. Continuum-like stress transmission mode was better simulated with Boussinesq (1885) model based on theory of elasticity compared to discrete. The soil-pore structure was greatly affected by increasing applied stresses. Total porosity was reduced 5-16% and macroporosity 50-85% at 620 kPa applied stress for the intact soils. Similarly, significant changes in the morphological indices of the macropore space were also observed with increasing applied stresses.

Soil susceptibility to compaction under use conditions in southern Brazil

Directory of Open Access Journals (Sweden)

Michael Mazurana

Full Text Available ABSTRACT The degree of soil compaction is intensified by its inadequate management, compaction being variable depending on soil type since even under identical management conditions, different types have different abilities to withstand load. The objective of this study was to evaluate the susceptibility to compaction of different classes of soils under no-tillage (NT croping system compared to the original condition. Thus, i soils with the same source material have distinct resistance to compression with increased NT adoption time; ii the most sensitive indicators of this change are the ratios mass:volume and volume:volume and; iii there is a relationship between resistance and compaction susceptibility with the amount and type of oxide. Soil samples were collected in areas under NT and under natural condition in order to assess the impact imposed by the NT on the attributes density and porosity, precompression stress and compressibility index and relate them to the oxide type of, and content in, the soils under study. The results show that the density and macroporosity were those most affected by the NT agricultural use, regardless of soil type, that is, its dynamic is related more to soil use and less to mineralogical characteristics. The soil resistance and compaction susceptibility were higher in soil developed in basalt, followed by those developed in sandstone and granite. Both the organic matter content and type and concentration of iron oxides were related to the soil resistance and susceptibility to compaction.

Soil compaction of various Central European forest soils caused by traffic of forestry machines with various chassis

Directory of Open Access Journals (Sweden)

Michal Allman

2015-12-01

Full Text Available Aim of study: The primary objective of this paper was to compare the effects of different types of forestry machine chassis on the compaction of the top layers of soil and to define the soil moisture content level, at which machine traffic results in maximum compaction.Area of study: Measurements were conducted in eight forest stands located in Slovakia and the Czech Republic. The soil types in the stands subjected to the study were luvisols, stagnosols, cambisols, and rendzinas.Material and Methods: The measurements were focused on tracked and wheeled (equipped with low pressure tyres cut-to-length machines, and skidders equipped with wide and standard tyres. The bulk density of soil was determined from soil samples extracted from the ruts, the centre of the skid trail, and the undisturbed stand. To determine soil moisture content, at which the soil is the most susceptible to compaction, the Proctor standard test was employed.Main results: The moisture content for maximal compaction fluctuated from 12% to 34.06%. Wheeled machines compacted the soil to 1.24 – 1.36 g.cm-3 (30.3 – 35.4 % compaction in dried state. Bulk density of soil in stands where tracked machine operated was lower, ranging from 1.02 to 1.06 g.cm-3 (25.3 % compaction.Research highlights: All wheeled machines caused the same amount of soil compaction in the ruts, despite differences in tyres, machine weight, etc. Maximum compaction caused by forestry machines occurred at minimal moisture contents, easily achievable in European climatic conditions.  Keywords: soil compaction; bulk density; soil moisture content limits; cut-to-length machines; skidders.

Effect of gravel on hydraulic conductivity of compacted soil liners

International Nuclear Information System (INIS)

Shelley, T.L.; Daniel, D.E.

1993-01-01

How much gravel should be allowed in low-hydraulic-conductivity, compacted soil liners? To address this question, two clayey soils are uniformly mixed with varying percentages of gravel that, by itself, has a hydraulic conductivity of 170 cm/s. Soil/gravel mixtures are compacted and then permeated. Hydraulic conductivity of the compacted gravel/soil mixtures is less than 1 x 10 -7 cm/s for gravel contents as high as 50-60%. For gravel contents ≤ 60%, gravel content is not important: all test specimens have a low hydraulic conductivity. For gravel contents > 50-60%, the clayey soils does not fill voids between gravel particles, and high hydraulic conductivity results. The water content of the nongravel fraction is found to be a useful indicator of proper moisture conditions during compaction. From these experiments in which molding water content and compactive energy are carefully controlled, and gravel is uniformly mixed with the soil, it is concluded that the maximum allowable gravel content is approximately 50%

Risk assessment of soil compaction in Walloon Region (Belgium)

Science.gov (United States)

Charlotte, Rosiere; Marie-France, Destain; Jean-Claude, Verbrugge

2010-05-01

The proposed Soil Framework Directive COM(2006)232 requires Member States to identify areas at risk of erosion, decline in organic matter, salinisation, compaction, sealing and landslides, as well as to set up an inventory of contaminated sites. The present project aims to identify the susceptibility to compaction of soils of the Walloon Region (Belgium) and to recommend good farming practices avoiding soil compaction as far as possible. Within this scope, the concept of precompression stress (Pc) (Horn and Fleige, 2003) was used. Pc is defined as the maximum major principal stress that a soil horizon can withstand against any applied external vertical stress. If applied stress is higher than Pc, the soil enters in a plastic state, not easily reversible. For a given soil, the intensity of soil compaction is mainly due to the applied load which depends on vehicle characteristics (axle load, tyre dimensions, tyre inflation pressure, and vehicle velocity). To determine soil precompression stress, pedotransfert functions of Lebert and Horn (1991) defined at two water suctions (pF 1.8 and 2.5) were used. Parameters required by these functions were found within several databases (Aardewerk and Digital Map of Walloon Soils) and literature. The validation of Pc was performed by measuring stress-strain relationships using automatic oedometers. Stresses of 15.6, 31, 3, 62.5, 125, 250, 500 and 1000 kPa were applied for 10 min each. In this study, the compaction due to beet harvesters was considered because the axle load can exceed 10 tons and these machines are often used during wet conditions. The compaction at two depth levels was considered: 30 and 50 cm. Compaction of topsoil was not taken into account because, under conventional tillage, the plough depth is lower than 25 cm. Before and after the passage of the machines, following measurements were performed: granulometry, density, soil moisture, pF curve, Atterberg limits, ... The software Soilflex (Keller et al., 2007

Defoliation and Soil Compaction Jointly Drive Large-Herbivore Grazing Effects on Plants and Soil Arthropods on Clay Soil

NARCIS (Netherlands)

van Klink, R.; Schrama, M.; Nolte, S.; Bakker, J. P.; WallisDeVries, M. F.; Berg, M. P.

In addition to the well-studied impacts of defecation and defoliation, large herbivores also affect plant and arthropod communities through trampling, and the associated soil compaction. Soil compaction can be expected to be particularly important on wet, fine-textured soils. Therefore, we

Defoliation and Soil Compaction Jointly Drive Large-Herbivore Grazing Effects on Plants and Soil Arthropods on Clay Soil

NARCIS (Netherlands)

van Klink, R.; Schrama, M.; Nolte, S.; Bakker, Jan P.; WallisDeVries, M.F.; Berg, M.P.

2015-01-01

In addition to the well-studied impacts of defecation and defoliation, large herbivores also affect plant and arthropod communities through trampling, and the associated soil compaction. Soil compaction can be expected to be particularly important on wet, fine-textured soils. Therefore, we

Visual soil evaluation and soil compaction research

DEFF Research Database (Denmark)

M.L. Guimarães, Rachel; Keller, Thomas; Munkholm, Lars Juhl

2017-01-01

Following on from discussions that took place during the 19th International Conference of the International Soil Tillage Research Organization (ISTRO) in Montevideo, Uruguay, in 2012, the ISTRO working groups “Visual Soil Examination and Evaluation” (VSEE) and “Subsoil Compaction” decided...... to organize a joint workshop. The present special issue is an outcome from the workshop on “Soil structural quality of tropical soils: Visual evaluation methods and soil compaction prevention strategies” that was held 26–29 May 2014 in Maringá, Paraná, Brazil. There has been a long-lasting interest in Visual...... Soil Evaluation (VSE). An ISTRO working group was established more than 30 years ago with the objectives to exchange knowledge and experiences on field methods of visual-tactile soil assessment and to foster international cooperation on new or refined methods. The three previous meeting of the group...

Recovery of severely compacted soils in the Mojave Desert, California, USA

Science.gov (United States)

Webb, R.H.

2002-01-01

Often as a result of large-scale military maneuvers in the past, many soils in the Mojave Desert are highly vulnerable to soil compaction, particularly when wet. Previous studies indicate that natural recovery of severely compacted desert soils is extremely slow, and some researchers have suggested that subsurface compaction may not recover. Poorly sorted soils, particularly those with a loamy sand texture, are most vulnerable to soil compaction, and these soils are the most common in alluvial fans of the Mojave Desert. Recovery of compacted soil is expected to vary as a function of precipitation amounts, wetting-and-drying cycles, freeze-thaw cycles, and bioturbation, particularly root growth. Compaction recovery, as estimated using penetration depth and bulk density, was measured at 19 sites with 32 site-time combinations, including the former World War II Army sites of Camps Ibis, Granite, Iron Mountain, Clipper, and Essex. Although compaction at these sites was caused by a wide variety of forces, ranging from human trampling to tank traffic, the data do not allow segregation of differences in recovery rates for different compaction forces. The recovery rate appears to be logarithmic, with the highest rate of change occurring in the first few decades following abandonment. Some higher-elevation sites have completely recovered from soil compaction after 70 years. Using a linear model of recovery, the full recovery time ranges from 92 to 100 years; using a logarithmic model, which asymptotically approaches full recovery, the time required for 85% recovery ranges from 105-124 years.

The physical properties and compaction characteristics of swelling soils

International Nuclear Information System (INIS)

Komine, Hideo; Ogata, Nobuhide

1990-01-01

Expansive soils have recently attracted increasing attention as the back filling material for the repositories of high level nuclear wastes or as the material for improving extremely soft grounds. However, since very little has been known concerning the physical and mechanical properties of such materials, it is necessary to clarify the swelling, compaction and thermal characteristics of expansive soils. For this purpose, various kinds of index tests and a series of static compaction tests were performed using several kinds of swelling soils in order to investigate the relationship between the fundamental physical properties and the compaction characteristics. Since the ordinary testing method stipulated in JIS is difficult to perform for such expansive soils, the new method was proposed to obtained the reliable values of specific gravity, grain size distribution and liquid/plastic limits. By this method, some representative values were presented for various kinds of clay including bentonite. As the results of static compaction tests, the compaction characteristics of clay were strongly dependent on the plastic limit of clay. The maximum dry density and optimum water content were strongly dependent on both plastic limit and compaction pressure. (K.I.)

Recovery of compacted soils in Mojave Desert ghost towns.

Science.gov (United States)

Webb, R.H.; Steiger, J.W.; Wilshire, H.G.

1986-01-01

Residual compaction of soils was measured at seven sites in five Mojave Desert ghost towns. Soils in these Death Valley National Monument townsites were compacted by vehicles, animals, and human trampling, and the townsites had been completely abandoned and the buildings removed for 64 to 75 yr. Recovery times extrapolated using a linear recovery model ranged from 80 to 140 yr and averaged 100 yr. The recovery times were related to elevation, suggesting freeze-thaw loosening as an important factor in ameliorating soil compaction in the Mojave Desert. -from Authors

Assessment of soil compaction properties based on surface wave techniques

Science.gov (United States)

Jihan Syamimi Jafri, Nur; Rahim, Mohd Asri Ab; Zahid, Mohd Zulham Affandi Mohd; Faizah Bawadi, Nor; Munsif Ahmad, Muhammad; Faizal Mansor, Ahmad; Omar, Wan Mohd Sabki Wan

2018-03-01

Soil compaction plays an important role in every construction activities to reduce risks of any damage. Traditionally, methods of assessing compaction include field tests and invasive penetration tests for compacted areas have great limitations, which caused time-consuming in evaluating large areas. Thus, this study proposed the possibility of using non-invasive surface wave method like Multi-channel Analysis of Surface Wave (MASW) as a useful tool for assessing soil compaction. The aim of this study was to determine the shear wave velocity profiles and field density of compacted soils under varying compaction efforts by using MASW method. Pre and post compaction of MASW survey were conducted at Pauh Campus, UniMAP after applying rolling compaction with variation of passes (2, 6 and 10). Each seismic data was recorded by GEODE seismograph. Sand replacement test was conducted for each survey line to obtain the field density data. All seismic data were processed using SeisImager/SW software. The results show the shear wave velocity profiles increase with the number of passes from 0 to 6 passes, but decrease after 10 passes. This method could attract the interest of geotechnical community, as it can be an alternative tool to the standard test for assessing of soil compaction in the field operation.

Effect of soil compactness on the growth and quality of carrot

Directory of Open Access Journals (Sweden)

Liisa Pietola

1995-05-01

Full Text Available Field experiments were performed in Southern Finland on three soil types: fine sand (1989-1991, clay (1989 and mull (1990-1991. The following soil mechanical treatments were applied to autumn ploughed land: soil loosening by ridge preparation (ridge distance 45 cm, rotary harrowing (to a depth of 20 cm, clay 15 cm, and soil compaction track by track by a tractor weighing 3 Mg (1 or 3 passes, wheel width 33 cm before seed bed preparation. One plot was untreated. These treatments were set up in April (on clay in May under moist soil conditions. Sprinkler irrigation (one application of 30 mm was applied to clay and fine sand when soil moisture in top soil had decreased to around 50% of plant-available water capacity. PVC cylinders (r = 15 cm, h = 60 cm were fixed in the experimental areas during the growing periods. At harvest, these cylinders were removed for specific analysis of tap and fibrous roots of carrot. Length and width of fibrous roots were quantified by image analysis in the USA. The impacts of soil loosening and partial compaction were determined by measuring soil physical parameters to a depth of 25 cm in mineral soils, and to greater depths in organic soil. Dry bulk densities of the plough layers increased with increasing tractor passes by 8%, 10% and 13% for fine sand, mull and clay soils, respectively. The lowest dry soil bulk density in the plough layer was obtained by rotary harrowing to a depth of 20 cm. Comparison of gamma ray transmission and gravimetric analysis indicated that dry soil bulk density was slightly lower when determined by gravimetric analysis. Increased soil bulk densities were reflected by increased water retention capacity (matric suction ≤ 10 kPa and greater penetrometer resistance. Relatively similar increases in bulk density increased the penetrometer resistance much less in mull than in fine sand. In contrast, greater bulk densities in the mull soil affected soil air composition adversely by decreasing

An interdisciplinary approach towards improved understanding of soil deformation during compaction

DEFF Research Database (Denmark)

Keller, T.; Lamandé, Mathieu; Peth, S.

2013-01-01

and validation of new soil compaction models. The integration of concepts underlying dynamic processes that modify soil pore spaces and bulk properties will improve the understanding of how soil management affect vital soil mechanical, hydraulic and ecological functions supporting plant growth.......Soil compaction not only reduces available pore volume in which fluids are stored, but it alters the arrangement of soil constituents and pore geometry, thereby adversely impacting fluid transport and a range of soil ecological functions. Quantitative understanding of stress transmission...... and deformation processes in arable soils remains limited. Yet such knowledge is essential for better predictions of effects of soil management practices such as agricultural field traffic on soil functioning. Concepts and theory used in agricultural soil mechanics (soil compaction and soil tillage) are often...

Challenges in the development of analytical soil compaction models

DEFF Research Database (Denmark)

Keller, Thomas; Lamandé, Mathieu

2010-01-01

and recommendations for the prevention of soil compaction often rely on simulation models. This paper highlights some issues that need further consideration in order to improve soil compaction modelling, with the focus on analytical models. We discuss the different issues based on comparisons between experimental......Soil compaction can cause a number of environmental and agronomic problems (e.g. flooding, erosion, leaching of agrochemicals to recipient waters, emission of greenhouse gases to the atmosphere, crop yield losses), resulting in significant economic damage to society and agriculture. Strategies...... data and model simulations. The upper model boundary condition (i.e. contact area and stresses at the tyre-soil interface) is highly influential in stress propagation, but knowledge on the effects of loading and soil conditions on the upper model boundary condition is inadequate. The accuracy of stress...

Compaction stimulates denitrification in an urban park soil using 15N tracing technique

DEFF Research Database (Denmark)

Li, Shun; Deng, Huan; Rensing, Christopher Günther T

2014-01-01

Soils in urban areas are subjected to compaction with accelerating urbanization. The effects of anthropogenic compaction on urban soil denitrification are largely unknown. We conducted a study on an urban park soil to investigate how compaction impacts denitrification. By using 15N labeling method...... and acetylene inhibition technique, we performed three coherent incubation experiments to quantify denitrification in compacted soil under both aerobic and anaerobic conditions. Uncompacted soil was set as the control treatment. When monitoring soil incubation without extra substrate, higher nitrous oxide (N2O......) flux and denitrification enzyme activity were observed in the compacted soil than in the uncompacted soil. In aerobic incubation with the addition of K15NO3, N2O production in the compacted soil reached 10.11 ng N h-1 g-1 as compared to 0.02 ng N h-1 g-1 in the uncompacted soil. Denitrification...

Effect of soil compaction on the degradation and ecotoxicological impact of isoproturon

Science.gov (United States)

Mamy, L.; Vrignaud, P.; Cheviron, N.; Perreau, F.; Belkacem, M.; Brault, A.; Breuil, S.; Delarue, G.; Touton, I.; Chaplain, V.

2009-04-01

Soil is essentially a non-renewable resource which performs many functions and delivers services vital to human activities and ecosystems survival. However the capacity of soil to keep on fully performing its broad variety of crucial functions is damaged by several threats and, among them, chemical contamination by pesticides and compaction due to intensive agriculture practices. How these two threats could interact is largely unknown: compaction may modify the fate of pesticides in soil therefore their effects on the biological functioning of soil. The aim of this work was to study the effect of soil compaction on (1) the degradation of one herbicide, isoproturon (2) the ecotoxicological impact of this herbicide measured through two enzyme activities involved in C (beta-glucosidase) and N (urease) cycles in soil. Undisturbed soil cylinders were sampled in the 2-4 cm layer of La Cage experimental site (INRA, Versailles, France), under intensive agriculture practices. Several soil samples were prepared with different bulk density then treated with isoproturon (IPU). The samples were incubated at 18 ± 1°C in darkness for 63 days. At 0, 2, 7, 14, 28 and 63 days, the concentrations of isoproturon and of two of its main metabolites in soil (monodesmethyl-isoproturon, IPPMU; didesmethyl-isoproturon, IPPU), and the enzyme activities were measured. The results showed that there was no significant difference in IPU degradation under no and moderate soil compaction. IPU was less persistent in the highly compacted soil, but this soil had also higher humidity which is known to increase the degradation. Only one metabolite, IPPMU, was detected independently of the conditions of compaction. The compaction did not modify the effect of IPU on beta-glucosidase and urease activities in the long term, but microbial communities were probably the same in all the soil samples that were initially not compacted. The communities developed in durably compacted zones in the field are

Generalized Density-Corrected Model for Gas Diffusivity in Variably Saturated Soils

DEFF Research Database (Denmark)

Chamindu, Deepagoda; Møldrup, Per; Schjønning, Per

2011-01-01

models. The GDC model was further extended to describe two-region (bimodal) soils and could describe and predict Dp/Do well for both different soil aggregate size fractions and variably compacted volcanic ash soils. A possible use of the new GDC model is engineering applications such as the design...... of highly compacted landfill site caps....

Estimation of Compaction Parameters Based on Soil Classification

Science.gov (United States)

Lubis, A. S.; Muis, Z. A.; Hastuty, I. P.; Siregar, I. M.

2018-02-01

Factors that must be considered in compaction of the soil works were the type of soil material, field control, maintenance and availability of funds. Those problems then raised the idea of how to estimate the density of the soil with a proper implementation system, fast, and economical. This study aims to estimate the compaction parameter i.e. the maximum dry unit weight (γ dmax) and optimum water content (Wopt) based on soil classification. Each of 30 samples were being tested for its properties index and compaction test. All of the data’s from the laboratory test results, were used to estimate the compaction parameter values by using linear regression and Goswami Model. From the research result, the soil types were A4, A-6, and A-7 according to AASHTO and SC, SC-SM, and CL based on USCS. By linear regression, the equation for estimation of the maximum dry unit weight (γdmax *)=1,862-0,005*FINES- 0,003*LL and estimation of the optimum water content (wopt *)=- 0,607+0,362*FINES+0,161*LL. By Goswami Model (with equation Y=mLogG+k), for estimation of the maximum dry unit weight (γdmax *) with m=-0,376 and k=2,482, for estimation of the optimum water content (wopt *) with m=21,265 and k=-32,421. For both of these equations a 95% confidence interval was obtained.

Assessing the environmental impacts of soil compaction in Life Cycle Assessment.

Science.gov (United States)

Stoessel, Franziska; Sonderegger, Thomas; Bayer, Peter; Hellweg, Stefanie

2018-07-15

Maintaining biotic capacity is of key importance with regard to global food and biomass provision. One reason for productivity loss is soil compaction. In this paper, we use a statistical empirical model to assess long-term yield losses through soil compaction in a regionalized manner, with global coverage and for different agricultural production systems. To facilitate the application of the model, we provide an extensive dataset including crop production data (with 81 crops and corresponding production systems), related machinery application, as well as regionalized soil texture and soil moisture data. Yield loss is modeled for different levels of soil depth (0-25cm, 25-40cm and >40cm depth). This is of particular relevance since compaction in topsoil is classified as reversible in the short term (approximately four years), while recovery of subsoil layers takes much longer. We derive characterization factors quantifying the future average annual yield loss as a fraction of the current yield for 100years and applicable in Life Cycle Assessment studies of agricultural production. The results show that crops requiring enhanced machinery inputs, such as potatoes, have a major influence on soil compaction and yield losses, while differences between mechanized production systems (organic and integrated production) are small. The spatial variations of soil moisture and clay content are reflected in the results showing global hotspot regions especially susceptible to soil compaction, e.g. the South of Brazil, the Caribbean Islands, Central Africa, and the Maharashtra district of India. The impacts of soil compaction can be substantial, with highest annual yield losses in the range of 0.5% (95% percentile) due to one year of potato production (cumulated over 100y this corresponds to a one-time loss of 50% of the present yield). These modeling results demonstrate the necessity for including soil compaction effects in Life Cycle Impact Assessment. Copyright © 2018

Soil compaction: alterations in physical, chemical and biological attributes in a fluvic neosoil

International Nuclear Information System (INIS)

Viana, Eliane Ferreira

2004-12-01

The efficient management of soil proposes the correct utilization of agricultural practices to minimize the loss of structure, compaction, and nutrient losses in the soil, which are the main causes of its degradation. Such concerns reside in the fact that the impact from compaction can also be related to the soil capacity for losing carbon. This effect has strong influence on CO 2 emissions to the atmosphere. On the other hand, induced mutation, a valuable tool for the development of genetic materials, that is tolerant to environmental adversities, can be helpful in the adaptation of crops in compacted soils. This study was conducted to evaluate isolated and combined effects of compaction, water content and organic amendments in soil respiration. Also it investigates the development of cowpea (V. unguiculata, L. Walp] var. IPA 206, in a Fluvic Neosoil, artificially compacted, with different fertilizer materials added (cowdung, NPK, organomineral I, and organomineral II). Also it evaluates the development of cowpea when the seeds were submitted to gamma irradiation ( 60 Co) and cultivated in compacted and non compacted soil, under greenhouse conditions, for 60 days. The isolated addition of spent coffee powder and marine algae to the soil increased the CO 2 evolution from soil, reflecting variations in dynamics of the heterotrophic soil microbiota. CO 2 evolution decreased with the increase in soil density, showing reductions in aeration. The values presented were found to be low in the treatment without addition of these materials (control) and showed them to be significantly increased in the treatments that received such residues, all over the incubation period. Plant height, root length, shoot dry matter production and dry matter of nodules diminished with the increase in soil density. The incorporation of the organomineral mixtures I and II to the artificially compacted soil, showed an increase in plant height, and root length, suggesting the beneficial action

Effects of Soil Compaction on Carbon and Nitrogen Sequestration in Soil and Wheat, Soil Physical Properties and Aggregates Stability (Case study: Northern of Aq Qala

Directory of Open Access Journals (Sweden)

Z. Saieedifar

2016-09-01

Full Text Available Introduction: Soil compaction has become a widespread problem in the world and it is considered as one of the main factors affecting land degradation in arid and semi-arid agricultural land. Compaction in arable soils is a gradual phenomenon that appearing over time and most important factors that influence it include: soil properties, high clay content, low organic matter, and frequency of wet-dry in the soil, impervious layer of soil, load heavy agricultural implements and soil and water mismanagement. Compaction induced soil degradation affects about 68 million hectares of land globally. The vast majority of compaction in modern agriculture is caused by vehicular traffic. Carbon sequestration by long-term management operation of the plant and soil, not only increase the soil carbon storage but also lead to reduce the carbon exchange and greenhouse gases emissions like CO2 from the soil profile. The aim of this study was evaluating the effect of soil compaction on carbon and nitrogen sequestration of wheat and soil and some soil physical properties such as: aggregate stability, saturated soil moisture content, bulk density and soil porosity. Materials and Methods: This experiment was accomplished in which is located near Aq Qala in a randomized completely block design (with 4 treatments and 3 replications. Soil compaction was artificially created by using a 5/7 ton heavy tractor. The treatments arrangements were: 1 T1: control, 2 T2: twice passing of tractor, 3 T3: four time of passing tractor, and 4 T4: six time of passing heavy tractor. Utilize of all agricultural inputs (fertilizers, herbicides, etc. has been identical for all treatments. Since rain-fed farming is the common method to cultivation of cereals in the study area, so no complementary irrigation was carried out in this period. In this study, after the measurement of the parameters, the data were analyzed by using SPSS 16.0 Software. LSD test was used for comparison of means

compaction delay versus properties of cement-bound lateritic soil

African Journals Online (AJOL)

hp

hour intervals on soil-cement mixes 3,5,8; and 1, 3, 5 percent cement contents by weight of dry soils, for ... stabilized soils were the Compaction test (Standard Proctor), the Unconfined Compressive. Strength .... Plastic limit (%). % passing BS ...

Laboratory testing of closure cap repair techniques

International Nuclear Information System (INIS)

Persoff, P.; Moridis, G.; Tuck, D.M.

1996-10-01

Landfill design requires a low permeability closure cap as well as a low permeability liner. The Savannah River Site, in South Carolina, has approximately 85 acres of mixed waste landfills covered with compacted kaolin clay. Maintaining low permeability of the clay cap requires both that the permeability of the compacted clay itself remain low and that the integrity of the barrier be maintained. Barrier breaches typically result from penetration by roots or animals, and especially cracks caused by uneven settling or desiccation. In this study, clay layers, 0.81 m in diameter and 7.6 cm thick, were compacted in 7 lysimeters to simulate closure caps. The hydraulic conductivity of each layer was measured, and the compacted clay layers (CCL's) were cracked by drying. Then various repair techniques were applied and the effectiveness of each repair was assessed by remeasuring the hydraulic conductivity. Finally the repaired CCL was again dried and measured to determine how the repair responded to the conditions that caused the original failure. For a full report of this investigation see Persoff et al. Six repair techniques have been tested, four of which involve the use of injectable barrier liquids colloidal silica (CS) and polysiloxane (PSX) described below: (I) covering the crack with a bentonite geosynthetic clay liner (GCL), (ii) recompaction of new kaolinite at STD+3 moisture content joined to existing kaolinite that had dried and shrunk, (iii) direct injection of colloidal silica to a crack, (iv) injection of colloidal silica (CS) to wells in an overlying sand layer, (v) direct injection of polysiloxane to a crack, and (vi), injection of polysiloxane (PSX) to wells in an overlying soil layer

Immediate and long term effects of compaction on the stress-strain behaviour of soil

Science.gov (United States)

Noor, Sarah T.; Chowdhury, Prantick; Chowdhury, Tasnim

2018-04-01

This paper explores whether delay in construction after compaction can benefit from the gain in soil’s strength and stability point of view. An experimental investigation has been carried out to examine the gradual development of soil’s shear strength by ageing of mechanically compacted soil at three relative densities. In order to separate the gain in strength due to ageing from that occurring from the reduction in soil moisture, the soil samples prepared in moulds were kept in desiccators for different periods of time (1, 9 and 17 days) before testing unconfined compressive strength test. The soil in densely compacted state is found to gain in strength due to ageing faster than that in medium compacted state. Only due to ageing of 9 days or more, unconfined compressive strength of compacted soil is found about 1.7 to 2.4 times of that attained in day 1 after compaction.

Hydro-mechanical paths within unsaturated compacted soil framed through water retention surfaces

Directory of Open Access Journals (Sweden)

Pelizzari Benjamin

2016-01-01

Full Text Available Compaction is a key issue of modern earthworks... From sustainable development, a need arise of using materials for compaction under given conditions that would normally be avoid due to unpredictable pathologies. The application of compaction on fine grained soils, without a change of gravimetric water content, lead to very important modifications of the void ratio and hence suction. Therefore the hydro-mechanical behaviour of fine grained soil need to be rendered around three variables: suction, void ratio, saturation degree or water content. The barring capacity of the soil is assessed through Penetrometers (In-situ manual penetrometer, CBR in order to assess gains through compaction. The three states variables are then assessed for in situ and frame through water retention surfaces, realized from Proctor tests, in which compaction effect and path could be described.

[Effects of compaction on diurnal variaaton of soil respiration in Larix gmellini plantation in summer].

Science.gov (United States)

He, Na; Wang, Li-hai

2010-12-01

Taking the Larix gmellinii plantation in the experimental forest farm of Northeast Forestry University as test object, and by using Li-8100 automatic instrument, the daily CO2 emission rate of soil in summer under different degrees of man-made compaction was measured, with the regression models established. There were significant differences in the diurnal variation of soil respiration rate under different degrees of man-made compaction. In CK (no compaction), the maximum value of soil respiration appeared at 15:30-17:30, and the minimum value appeared at 03:30-05:30, which were obviously lagged behind those in compaction treatments. The maximum and minimum values of soil respiration rate in main roads appeared at 09:30-11:30 and 23:30-01:30, and those in branch roads appeared at 11:30 and 01:30-03:30, respectively. In all treatments, soil respiration rate had significant correlations with surface temperature, relative humidity, and the temperature at 10 cm soil depth, but the correlation with the soil moisture at 5 cm depth tended to be not significant when the compaction degree was increasing. Compaction altered surface soil physical structure, decreased surface soil CO2 release rate.

Compaction comparison testing using a modified impact soil tester and nuclear density gauge

Energy Technology Data Exchange (ETDEWEB)

Erchul, R.A.

1999-07-01

The purpose of this paper is to compare test results of a modified Impact Soil Tester (IST) on compacted soil with data obtained from the same soil using a nuclear density gauge at the US Army Corp of Engineer's Buena Vista Flood Wall project in Buena Vista, Virginia. The tests were run during construction of the earth flood wall during the summer of 1996. This comparison testing demonstrated the credibility of the procedure developed for the IST as a compacting testing device. The comparison data was obtained on a variety of soils ranging from silty sands to clays. The Flood Wall comparison compaction data for 90% Standard Proctor shows that the results of the IST as modified are consistent with the nuclear density gauge 89% of the time for all types of soil tested. However, if the soils are more cohesive than the results are consistent with the nuclear density gauge 97% of the time. In addition these comparison tests are in general agreement with comparison compaction testing using the same testing techniques and methods of compacted backfill in utility trenches conducted earlier for the Public Works Department, Chesterfield County, Virginia.

Compaction comparison testing using a modified impact soil tester and nuclear density gauge

International Nuclear Information System (INIS)

Erchul, R.A.

1999-01-01

The purpose of this paper is to compare test results of a modified Impact Soil Tester (IST) on compacted soil with data obtained from the same soil using a nuclear density gauge at the US Army Corp of Engineer's Buena Vista Flood Wall project in Buena Vista, Virginia. The tests were run during construction of the earth flood wall during the summer of 1996. This comparison testing demonstrated the credibility of the procedure developed for the IST as a compacting testing device. The comparison data was obtained on a variety of soils ranging from silty sands to clays. The Flood Wall comparison compaction data for 90% Standard Proctor shows that the results of the IST as modified are consistent with the nuclear density gauge 89% of the time for all types of soil tested. However, if the soils are more cohesive than the results are consistent with the nuclear density gauge 97% of the time. In addition these comparison tests are in general agreement with comparison compaction testing using the same testing techniques and methods of compacted backfill in utility trenches conducted earlier for the Public Works Department, Chesterfield County, Virginia

Soil compaction: Evaluation of stress transmission and resulting soil structure

DEFF Research Database (Denmark)

Naveed, Muhammad; Schjønning, Per; Keller, Thomas

strength. As soon as the applied load is lower than the aggregate strength, the mode of stress transmission is discrete as stresses were mainly transmitted through chain of aggregates. With increasing applied load soil aggregates start deforming that transformed heterogeneous soil into homogenous......, as a result stress transmission mode was shifted from discrete towards more like a continuum. Continuum-like stress transmission mode was better simulated with Boussinesq (1885) model based on theory of elasticity compared to discrete. The soil-pore structure was greatly affected by increasing applied...... and compaction-resulted soil structure at the same time. Stress transmission was quantified using both X-ray CT and Tactilus sensor mat, and soil-pore structure was quantified using X-ray CT. Our results imply that stress transmission through soil highly depends on the magnitude of applied load and aggregate...

On the seepage voids in the compacted soil observed by the x-ray imaging method

International Nuclear Information System (INIS)

Tokunaga, Koichi; Koga, Kiyoshi

1991-01-01

The structure of large voids in the soil layer by banking and rolling compaction and the form of the water channel structure seeping through soil layers have important significance in geotechnical engineering, and it was decided to examine them by the heavy liquid infiltration method developed recently by one of the authors. It has been known that the water permeability of soil due to compaction varies remarkably according to the water content in the soil at the time of compaction. However, the factor which determines the water permeability is related to the voids in soil, particularly the form of large voids which become water channel. As for the heavy liquid infiltration method, the sample soil is set similarly to the permeability test of compacted soil, and liquid contrast medium is infiltrated. The stereoscopic photographing is carried out as it is, and the path of the contrast medium infiltrating into soil, namely the form of the voids corresponding to water channel can be observed. Sample soil, the experimental method and the results are reported. The compaction permeability curves have the same tendency in volcanic ash soil and red clay. (K.I.)

Evaluation of in situ capping with clean soils to control phosphate release from sediments

Energy Technology Data Exchange (ETDEWEB)

Xu, Di [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Ding, Shiming, E-mail: smding@niglas.ac.cn [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Sun, Qin [College of Environmental Science and Engineering, Hohai University, Nanjing (China); Zhong, Jicheng [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Wu, Wei; Jia, Fei [College of Environmental Science and Engineering, Hohai University, Nanjing (China)

2012-11-01

Evaluation of in situ capping with clean soils to control phosphate release from the sediments of a eutrophic bay in Lake Taihu was performed after 18 months of capping. The concentrations of dissolved reactive phosphate (DRP) in pore waters and DRP resupply from native sediments and capped sediments were determined using high-resolution dialysis (HR-Peeper) and a Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique. The adsorption isotherm of these sediments was further investigated using a modified Langmuir model. The results showed low concentrations of DRP in pore waters with a low resupply from the sediments for sustaining pore water DRP concentration after capping. The calculated flux to the overlying water following the capping treatment was approximately half of that for the native sediments, implying that the capping reduced the release of phosphate from the sediments. The low resupply of the sediments after capping was further demonstrated by larger partitioning coefficient (K{sub p}) values and greater adsorption capacity (Q{sub max}) values, while zero equilibrium concentrations (EPC{sub 0}s) were similar to those in native sediments. The larger K{sub p} and Q{sub max} were attributed to higher active Fe and Al introduced by the capping, indicating that the binding of phosphate onto the active Fe and Al played a critical role in reducing the internal loading of phosphorous. Highlights: Black-Right-Pointing-Pointer Evaluation of capping with soils was performed through high-resolution sampling. Black-Right-Pointing-Pointer Capping decreased the concentrations of DRP in pore waters and its release to waters. Black-Right-Pointing-Pointer Capping decreased the resupply of pore water DRP from the sediments. Black-Right-Pointing-Pointer Capped sediments had stronger abilities to adsorb and retain P. Black-Right-Pointing-Pointer Active Fe and Al introduced by capping played a critical role.

Evaluation of in situ capping with clean soils to control phosphate release from sediments

International Nuclear Information System (INIS)

Xu, Di; Ding, Shiming; Sun, Qin; Zhong, Jicheng; Wu, Wei; Jia, Fei

2012-01-01

Evaluation of in situ capping with clean soils to control phosphate release from the sediments of a eutrophic bay in Lake Taihu was performed after 18 months of capping. The concentrations of dissolved reactive phosphate (DRP) in pore waters and DRP resupply from native sediments and capped sediments were determined using high-resolution dialysis (HR-Peeper) and a Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique. The adsorption isotherm of these sediments was further investigated using a modified Langmuir model. The results showed low concentrations of DRP in pore waters with a low resupply from the sediments for sustaining pore water DRP concentration after capping. The calculated flux to the overlying water following the capping treatment was approximately half of that for the native sediments, implying that the capping reduced the release of phosphate from the sediments. The low resupply of the sediments after capping was further demonstrated by larger partitioning coefficient (K p ) values and greater adsorption capacity (Q max ) values, while zero equilibrium concentrations (EPC 0 s) were similar to those in native sediments. The larger K p and Q max were attributed to higher active Fe and Al introduced by the capping, indicating that the binding of phosphate onto the active Fe and Al played a critical role in reducing the internal loading of phosphorous. Highlights: ► Evaluation of capping with soils was performed through high-resolution sampling. ► Capping decreased the concentrations of DRP in pore waters and its release to waters. ► Capping decreased the resupply of pore water DRP from the sediments. ► Capped sediments had stronger abilities to adsorb and retain P. ► Active Fe and Al introduced by capping played a critical role.

Burial trench dynamic compaction demonstration at a humid site

International Nuclear Information System (INIS)

Spalding, B.P.

1985-01-01

This task has the objective of determining the degree of consolidation which can be achieved by dynamic compaction of a closed burial trench within a cohesive soil formation. A seven-year-old burial trench in Solid Waste Storage Area (SWSA) 6 of Oak Ridge National Laboratory (ORNL) was selected for this demonstration. This 251 m 3 trench contained about 80 Ci of mixed radionuclides, mostly 90 Sr, in 25 m 3 of waste consisting of contaminated equipment, dry solids, and demolition debris. Prior to compaction, a total trench void space of 79 m 3 was measured by pumping the trench full of water with corrections for seepage. Additional pre-compaction characterization included trench cap bulk density (1.68 kg/L), trench cap permeability (3 x 10 -7 m/s), and subsurface waste/backfill hydraulic conductivity (>0.01 m/s). Compaction was achieved by repeatedly dropping a 4-ton steel-reinforced concrete cylinder from heights of 4 to 8 m using the whipline of a 70-ton crane. The average trench ground surface was depressed 0.79 m, with some sections over 2 m, yielding a surveyed volumetric depression which totaled to 64% of the measured trench void space. Trench cap (0 to 60 cm) bulk density and permeability were not affected by compaction indicating that the consolidation was largely subsurface. Neither surface nor airborne radioactive contamination were observed during repeated monitoring during the demonstration. Dynamic compaction was shown to be an excellent and inexpensive (i.e., about $20/m 2 ) method to collapse trench void space, thereby hastening subsidence and stabilizing the land surface. 15 refs., 10 figs., 3 tabs

Determining Optimal Degree of Soil Compaction for Balancing Mechanical Stability and Plant Growth Capacity

National Research Council Canada - National Science Library

Goldsmith, Wendi

2001-01-01

.... Agronomists, on the other hand, recommend minimal soil compaction because compacted soils are widely understood to impede the growth and development of crops, forests, and native plant communities...

Compaction of an inceptisol caused by forest extraction with Skidder

Directory of Open Access Journals (Sweden)

José Carlos Pezzoni Filho

2014-06-01

Full Text Available The compaction due to machinery traffic causes damage to the soil that can interfere with the development of the root system of plants, resulting in decreased crop yields. The objective of this study was to evaluate the Inceptisol compaction caused by Skidder traffic in extraction of Pinus elliottii var. elliottii in secondary extension logging in tire tracks and stems, varying the frequency of tractor traffic. The tire tracks and stems were in the same line of traffic passage earlier, each located in their respective tracks. The study area was located in the municipality of Capão Bonito-SP, in cultivation of Pinus elliottii var. elliottii and samples were obtained from an area without traffic (control and applications with 1, 2, 3, 4 and 5 Skidder passes in two layers, 0.00 to 0.05 and 0.10 - 0.15 m depth. The results showed that there was additional compaction by each passage of the Skidder, being higher in the layer of 0.00 to 0.05 m depth. Soil compaction was more pronounced under lower water content in the soil, being contrary to the expected.

INTERACTION OF A LONG PILE OF FINITE STIFFNESS WITH SURROUNDING SOIL AND FOUNDATION CAP

Directory of Open Access Journals (Sweden)

Ter-Martirosyan Zaven Grigor’evich

2015-09-01

Full Text Available The article presents the formulation and analytical solution to a quantification of stress strain state of a two-layer soil cylinder enclosing a long pile, interacting with the cap. The solution of the problem is considered for two cases: with and without account for the settlement of the heel and the underlying soil. In the first case, the article is offering equations for determining the stresses of pile’s body and the surrounding soil according to their hardness and the ratio of radiuses of the pile and the surrounding soil cylinder, as well as formulating for determining equivalent deformation modulus of the system “cap-pile-surrounding soil” (the system. Assessing the carrying capacity of the soil under pile’s heel is of great necessity. In the second case, the article is solving a second-order differential equation. We gave the formulas for determining the stresses of the pile at its top and heel, as well as the variation of stresses along the pile’s body. The article is also formulating for determining the settlement of the foundation cap and equivalent deformation modulus of the system. It is shown that, pushing the pile into underlying layer results in the reducing of equivalent modulus of the system.

Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity.

Science.gov (United States)

Michael P. Amaranthus; Debbie Page-Dumroese; Al Harvey; Efren Cazares; Larry F. Bednar

1996-01-01

Three levels of organic matter removal (bole only; bole and crowns; and bole, crowns, and forest floor) and three levels of mechanical soil compaction (no compaction, moderate compaction, and severe soil compaction) were studied as they influence Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and western white...

Computer modeling analysis using compacted soil liner for capping layer at the LLW Radioactive Repository (Landfill) in Bukit Keledang

International Nuclear Information System (INIS)

Mohd Jamil Hashim; Mohd Abdul Wahab Yusof; Mohd Raihan Taha

2007-01-01

The VHELP 2.2v computer program is a landfill modeling to study the performance of varies layer in the radioactive repository or landfill. The water balance for the whole repository will be presented in hydrologic parameters such as hydraulic conductivity, runoff, rainfall, surcharge, percolation and evapotranspiration . This study includes the selection and laboratory testing of material density, porosity, void ratio and moisture in achieving the required hydraulic conductivity in gaining water balance. Hence the integrity of the layer will be predicted through out its life span limited to 100 years. This modeling allows us to formulate better compaction method deriving suitable Compacted Soil Liner to control cracks, bath-tub effects, leach-ate discharge and repository stability. The lysimeter samplings and double ring infiltrometer were used in obtaining the actual hydraulic conductivity. This parameter gives modeling input better understanding of the water infiltration and provides better repository profile design to gain water balance. These studies are the first attempt to examine the radioactive repository design profile in containing and surcharge outflow to the ground water. Therefore the acquired knowledge will be beneficial for the construction of the up coming national repository and all existing municipal landfill design. (Author)

Application of Optimum Compaction Energy in the Development of Bricks Made with Construction Trash Soils

Directory of Open Access Journals (Sweden)

T. Lopez-Lara

2014-01-01

Full Text Available In general, bricks frequently show different densities and therefore different resistances because the compaction energy is not considered in their production. Expansive soils represent a problem for light buildings over them because of volumetric instability. A generalized solution has been to extract them and substitute them by inert soil; thus they become construction trash. So, in this work the compaction energy aspect and the use of construction trash soils in the elaboration of resistant masonry bricks of homogeneous and controlled density are a new contribution in the production of bricks of better quality. First, the soil was stabilized with CaOH which leads to a decrease in its volumetric changes. Then, they were compacted with a specific energy for obtaining an optimal and maximum controlled density to ensure an increase in strength. Our results show that two optimal compaction energies can be considered with respect to the variation of optimum moisture in masonry bricks of expansive soil stabilized with lime. The first is when the optimal humidity reaches its smallest value (integrated soil lumps and the second is when humidity increases (disintegrated soil lumps, after reaching its lowest value. We also conclude that high compaction energy does not improve density values.

Errors in determination of soil water content using time-domain reflectometry caused by soil compaction around wave guides

Energy Technology Data Exchange (ETDEWEB)

Ghezzehei, T.A.

2008-05-29

Application of time domain reflectometry (TDR) in soil hydrology often involves the conversion of TDR-measured dielectric permittivity to water content using universal calibration equations (empirical or physically based). Deviations of soil-specific calibrations from the universal calibrations have been noted and are usually attributed to peculiar composition of soil constituents, such as high content of clay and/or organic matter. Although it is recognized that soil disturbance by TDR waveguides may have impact on measurement errors, to our knowledge, there has not been any quantification of this effect. In this paper, we introduce a method that estimates this error by combining two models: one that describes soil compaction around cylindrical objects and another that translates change in bulk density to evolution of soil water retention characteristics. Our analysis indicates that the compaction pattern depends on the mechanical properties of the soil at the time of installation. The relative error in water content measurement depends on the compaction pattern as well as the water content and water retention properties of the soil. Illustrative calculations based on measured soil mechanical and hydrologic properties from the literature indicate that the measurement errors of using a standard three-prong TDR waveguide could be up to 10%. We also show that the error scales linearly with the ratio of rod radius to the interradius spacing.

EFFECTS OF COMPACTIVE EFFORTS ON GEOTECHNICAL PROPERTIES OF SPENT ENGINE OIL CONTAMINATED LATERITE SOIL

Directory of Open Access Journals (Sweden)

OLUREMI, J. ROTIMI

2017-03-01

Full Text Available Investigation of the effects of compactive efforts and spent engine oil (SEO contamination on the geotechnical properties of lateritic soils was made. Contaminated specimens were prepared by mixing lateritic soil with up to 10 % SEO by dry weight of the soil in step concentration of 2 % and subjected to geotechnical tests. Results indicated a decrease in the fine content, decrease in liquid limit, maximum dry density (MDD and unconfined compressive strength (UCS with up to 10 % SEO content. No general trend was observed in the optimum moisture content (OMC with increasing SEO content. The MDD, OMC and UCS values increased with increase in the compactive effort. Regression analysis of the results showed that optimum moisture content, fine content and compactive effort significantly influence the soils UCS values. Analysis of variance showed that SEO and compactive effort has significant effect on the parameters with the exception in one case. The results of laboratory tests showed that geotechnical properties of the SEO contaminated soil were immensely impaired.

A study on water infiltration barriers with compacted layered soils

International Nuclear Information System (INIS)

Umeda, Y.; Komori, K.; Fujiwara, A.

1993-01-01

In shallow-ground disposal of low-level radioactive wastes, water movements due to natural processes in the soil covering the disposal facility must be properly controlled. A capillary barrier with compacted layered soils can provide an effective means of controlling water movement in the soil covering placed on a low-level radioactive waste disposal facility. An experiment was performed to determine the effectiveness of a full-scale fill as a capillary barrier. The fill used in the experiment was constructed of compacted layers of clay, fine sand, and gravel. Man-made rain was caused to fall on the surfaces of the fill to observe the infiltration of rainwater into the fill and to measure the amount of water drained from within. The experiment established the effectiveness of the capillary barrier

compressibility characteristics of compacted black cotton soil treated

African Journals Online (AJOL)

eobe

E-mail addresses: 1111 aeberemu@yahoo.com, 2222sadat1010@live.com. Abstract. One dimensional consolidation studies on compacted black cotton soil treated with up to 16% rice .... 80% of the organic matter of the husk is burnt off and.

An approach for modeling the influence of wheel tractor loads and vibration frequencies on soil compaction

Science.gov (United States)

Verotti, M.; Servadio, P.; Belfiore, N. P.; Bergonzoli, S.

2012-04-01

Both soil compaction and ground vibration are forms of environmental degradation that may be understood in the context of the vehicle-soil interaction process considered (Hildebrand et al., 2008). The transit of tractors on agricultural soil is often the main cause of soil compaction increasing. As known, this can be a serious problems for tillage and sowing and therefore the influence of all the affecting factors have been extensively studied in the last decades in order to understand their impact on the biosystem. There are factors related to the climate, namely to the rainfalls and temperature, and many others. Hence, it is not simple to figure out a complete model for predicting an index of compaction, for a given situation. Soil compaction models are important tools for controlling soil compaction due to agricultural field traffic and they are potentially useful technique to provide information concerning correct soil management. By means of such models, strategies and recommendations for prevention of soil compaction may be developed and specific advice may be given to farmers and advisers. In order to predict field wheeled and tracked vehicle performance, some empirical methods, used for off-road vehicle, were applied by Servadio (2010) on agricultural soil. The empirical indexes included, besides the soil strength, the load carried by the tire or track, some technical characteristics of the tire or track of the vehicle (tire or track width, tire or track wheel diameter, unloaded tire section height, number of wheel station in one track, tire deflection, total length of the belt track, the track pitch) as well as the vehicle passes. They have been validated with the tests results of agricultural vehicles over a range of soil in central Italy. Among the parameters which affect soil compaction, the water content of the soil, the axle load and number of vehicle passes proved to be the most important ones. The present paper concerns mainly vehicle-soil

Compaction and soil fertility after eucalyptus harvesting using Feller Buncher and Skidder

Directory of Open Access Journals (Sweden)

Ana Lúcia Piedade Sodero Martins Pincelli

2014-06-01

Full Text Available This study analyzed, the impact of Feller Buncher and Skidder traffic in harvesting areas of eucalyptus in Mogi Guaçu, considering the compaction and fertilization effects in the range of soil next to the carrier during the cycle of forest growth. An increase in soil compaction, caused by machinery traffic in topsoil (0-10 cm, was observed in the area recently harvested. The soils of the study areas, with eucalyptus 1.4 and 6.0 years old, showed good fertility conditions, especially the older area, where decomposition of forest residues possibly contributed to such fertility.

Inter- and Intra- Field variations in soil compaction levels and subsequent impacts on hydrological extremes

Science.gov (United States)

Pattison, Ian; Coates, Victoria

2015-04-01

The rural landscape in the UK is dominated by pastoral agriculture, with about 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Intensification has resulted in greater levels of compaction associated with higher stocking densities. However, there is likely to be a great amount of variability in compaction levels within and between fields due to multiple controlling factors. This research focusses in on two of these factors; firstly animal species, namely sheep, cattle and horses; and secondly field zonation e.g. feeding areas, field gates, open field. Field experiments have been conducted in multiple fields in the River Skell catchment, in Yorkshire, UK, which has an area of 140km2. The effect on physical and hydrologic soil characteristics such as bulk density and moisture contents have been quantified using a wide range of field and laboratory based experiments. Results have highlighted statistically different properties between heavily compacted areas where animals congregate and less-trampled open areas. Furthermore, soil compaction has been hypothesised to contribute to increased flood risk at larger spatial scales. Previous research (Pattison, 2011) on a ~40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. Here we report results from spatially distributed hydrological modelling using soil parameters gained from the field experimentation. Results highlight the importance of both the percentage of the catchment which is heavily compacted and also the spatial distribution of these fields.

Traffic effects on soil compaction and sugar beet (Beta vulgaris L.) taproot quality parameters

Energy Technology Data Exchange (ETDEWEB)

Marinello, F.; Pezzuolo, A.; Cillis, D.; Chiumenti, A.; Sartori, L.

2017-09-01

Soil compaction is a critical issue in agriculture having a significant influence on crop growth. Sugar beet (Beta vulgaris L.) is accounted as a crop susceptible to compaction. Reduction of leaf area, final yield, and root quality parameters are reported in compacted soils. The most obvious visual indicator of topsoil compaction is root depth affected by agricultural tractor and machinery traffic up on the soil. Such indicators are mainly correlated to initial soil condition, tyre features, and number of passages. Monitoring and controlling frequency and position of machine traffic across the field, in such a way that passages are completed on specific, well-defined tracks, can assist with minimization of compaction effects on soil. The objective of the present work was to analyze the subsoil compaction during the growing period of sugar beet with different farming approaches including controlled traffic passages and random traffic. To this end, tests were carried out following each agro technical operation using penetrometer readings in order to monitor the state of cone-index after each step. In addition, at the harvesting time, root quality parameters were analyzed with particular attention to length and regularity of the taproot, total length, circumference, mass, and above-ground biomass. Such parameters were usefully implemented in order to evaluate the effects of controlled traffic passages compared to the random traffic in a cultivation of sugar beet. Results highlight how an increase in crop yield, derived from samples monitored, higher than 10% can be expected with implementation of a careful traffic management.

Improvement of Base and Soil Construction Quality by Using Intelligent Compaction Technology : Final Report.

Science.gov (United States)

2017-08-01

Intelligent Compaction (IC) technique is a fast-developing technology for base and soil compaction quality control. Proof-rolling subgrades and bases using IC rollers upon completion of compaction can identify the less stiff spots and significantly i...

Driver-Pressure-State-Impact-Response (DPSIR) analysis and risk assessment for soil compaction

DEFF Research Database (Denmark)

Schjønning, Per; van den Akker, Jan J.H.; Keller, Thomas

2015-01-01

Compaction of subsoil is a hidden but persistent damage that impairs a range of soil functions and ecosystem services. We analyzed the soil compaction issue in the Driver-Pressure-State-Impact-Response (DPSIR) context. The driving force (DPSIR-D) is the farmers' efforts to sustain economic...... are not able to carry the loads frequently inflicted on wet soil without exerting critical stresses on deep subsoil layers. We suggest the use of online modeling tools that combine existing knowledge. Such tools may also create maps of vulnerable areas from the field to the continent scale. Groups...

Risk assessment of soil compaction in Europe – Rubber tracks or wheels on machinery

DEFF Research Database (Denmark)

Lamandé, Mathieu; Greve, Mogens Humlekrog; Schjønning, Per

2018-01-01

Subsoil compaction is persistent and affects the wide diversity of ecological services provided by agricultural soils. Efficient risk assessment tools are required to identify sustainable agricultural practices. Vehicles should not transmit stresses that exceed soil strength. Wheel load is the pr......Subsoil compaction is persistent and affects the wide diversity of ecological services provided by agricultural soils. Efficient risk assessment tools are required to identify sustainable agricultural practices. Vehicles should not transmit stresses that exceed soil strength. Wheel load...... the magnitude of contact stresses, (ii) compare effects of traffic on soil physical properties using tires or tracks, and (iii) evaluate a state-of-the-art method for risk assessment of soil compaction beneath tracks or tires at the European level. We measured contact stress below a fully-loaded sugar beet....... The contact area was larger and the maximum and vertical stress smaller beneath the rubber track than beneath the tire. Nevertheless, stress distribution beneath the rubber track was far from uniform, presenting high peak stresses beneath the wheels and rollers. Dry bulk density was similar after traffic...

Load and inflation pressure effects on soil compaction of forwarder tires

Science.gov (United States)

Tim McDonald; Tom Way; Bjorn Lofgren; Fernando Seixas; Mats Landstrom

1996-01-01

A standard forwarder tire (600/55-26.5) was tested to determine its range of soil compaction with various inflation pressures and dynamic loads. Past research has shown that compaction of heavier equipment can be somewhat mitigated by operating with lower inflation pressures. Results indicated a significant effect of both load and inflation pressure on bulk density,...

Can differences in root responses to soil drying and compaction explain differences in performance of trees growing on landfill sites?

Science.gov (United States)

Liang, Jiansheng; Zhang, Jianhua; Chan, Gilbert Y. S.; Wong, M. H.

1999-07-01

Two tropical woody species, Acacia confusa Merrill and Litsea glutinosa (Lour.) C.B. Robinson, were grown under controlled conditions in PVC pipes filled with John Innes No. 2 soil. To investigate root distribution, physiological characteristics and hydraulic conductivity, four soil treatments were imposed-well-watered and noncompacted (control), well-watered and compacted; unwatered and noncompacted, and unwatered and compacted. In L. glutinosa, rooting depth and root elongation were severely restricted when soil bulk density increased from around 1.12 to 1.62 g cm(-3), whereas soil compaction had little effect on these parameters in A. confusa. As soil drying progressed, root water potential and osmotic potential declined more slowly in L. glutinosa than in A. confusa. Both the soil drying and compaction treatments significantly stimulated the accumulation of root abscisic acid (ABA) in both species. Soil drying damaged the root cell membrane of A. confusa, but had little influence on the root cell membrane of L. glutinosa. Soil drying had a greater effect on root hydraulic conductivity (L(p)) in L. glutinosa than in A. confusa, whereas the effect of soil compaction on L(p) was less in L. glutinosa than in A. confusa. Soil drying enhanced the effects of soil compaction on root L(p). We conclude that soil drying and compaction have large species-specific effects on the distribution, growth and physiology of roots. The relationships of these root properties to the species' ability to tolerate unfavorable soil conditions were examined.

Composition and structure of aggregates from compacted soil horizons in the southern steppe zone of European Russia

Science.gov (United States)

Sorokin, A. S.; Abrosimov, K. N.; Lebedeva, M. P.; Kust, G. S.

2016-03-01

The composition and structure of aggregates from different agrogenic soils in the southern steppe zone of European Russia have been studied. It is shown that the multi-level study (from the macro- to microlevel) of these horizons makes it possible to identify soil compaction caused by different elementary soil processes: solonetz-forming, vertisol-forming, and mechanical (wheel) compaction in the rainfed and irrigated soils. The understanding of the genesis of the compaction of soil horizons (natural or anthropogenic) is important for the economic evaluation of soil degradation. It should enable us to make more exact predictions of the rates of degradation processes and undertake adequate mitigation measures. The combined tomographic and micromorphological studies of aggregates of 1-2 and 3-5 mm in diameter from compacted horizons of different soils have been performed for the first time. Additional diagnostic features of negative solonetz- forming processes (low open porosity of aggregates seen on tomograms and filling of a considerable part of the intraped pores with mobile substance) and the vertisol-forming processes (large amount of fine intraaggregate pores seen on tomograms and a virtual absence of humus-clay plasma in the intraped zone)—have been identified. It is shown that the combination of microtomographic and micromorphological methods is helpful for studying the pore space of compacted horizons in cultivated soils.

The effect of mulching and soil compaction on fungi composition and microbial communities in the rhizosphere of soybean

Science.gov (United States)

Frac, M.; Siczek, A.; Lipiec, J.

2009-04-01

The soil environment is the habitat of pathogenic and saprotrophic microorganisms. The composition of the microbial community are related to biotic and abiotic factors, such as root exudates, crop residues, climate factors, mulching, mineral fertilization, pesticides introduction and soil compaction. The aim of the study was to determine the effect of the mulching and soil compaction on the microorganism communities in the rhizosphere soil of soybean. The studies were carried out on silty loam soil (Orthic Luvisol) developed from loess (Lublin, Poland). The experiment area was 192m2 divided into 3 sections consisted of 6 micro-plots (7m2). Three levels of soil compaction low, medium and heavy obtained through tractor passes were compared. The soil was compacted and loosened within seedbed layer 2 weeks before sowing. Soybean "Aldana" seeds were inoculated with Bradyrhizobium japonicum and were sown with interrow spacing of 0.3m. Wheat straw (as mulch) was uniformly spread on the half of each micro-plot at an amount of 0.5kg m-1 after sowing. Rhizosphere was collected three times during growing season of soybean. Microbiological analyses were conducted in 3 replications and included the determination of: the total number of bacteria and fungi, the number of bacteria Pseudomonas sp. and Bacillus sp., the genus identification of fungi isolated from rhizosphere of soybean. Results indicated a positive effect of mulching on the increase number of all groups of examined rhizosphere microorganisms (fungi, bacteria, Pseudomonas sp., Bacillus sp.). The highest number of the microorganisms was found in the low and medium compacted soil and markedly decreased in the most compacted soil. Relatively high number of antagonistic fungi (Penicillium sp., Trichoderma sp.) was recorded in the rhizosphere of low and medium compacted soil, particularly in mulched plots. The presence of these fungi can testify to considerable biological activity, which contributes to the improvement of

Application of Optimum Compaction Energy in the Development of Bricks Made with Construction Trash Soils

OpenAIRE

Lopez-Lara, T.; Gonzalez-Vega, C. L.; Hernandez-Zaragoza, J. B.; Rojas-Gonzalez, E.; Carreón-Freyre, D.; Salgado-Delgado, R.; Garcia-Hernandez, E.; Cerca, M.

2014-01-01

In general, bricks frequently show different densities and therefore different resistances because the compaction energy is not considered in their production. Expansive soils represent a problem for light buildings over them because of volumetric instability. A generalized solution has been to extract them and substitute them by inert soil; thus they become construction trash. So, in this work the compaction energy aspect and the use of construction trash soils in the elaboration of resistan...

SHEAR STRENGTH, COLLAPSIBILITY AND COMPRESSIBILITY CHARACTERISTICS OF COMPACTED BAIJI DUNE SOILS

Directory of Open Access Journals (Sweden)

ABBAS JAWAD AL-TAIE

2017-03-01

Full Text Available Baiji city is a vital industrial centre in Iraq since it has the biggest oil refinery. Therefore, Baiji has become an attractive site for strategic construction projects. Dune sand covers about 220 km2 of the area of Baiji city. However, few researches had attempted to study its behaviour. In this study laboratory tests were conducted to determine the shear strength, collapsibility and compressibility of the dune sand at its natural and compacted status. The effect of dry unit weight, moisture content, relative density and soaking on mechanical properties of dune soil was investigated. The results demonstrated that dry and soaked dune specimens tested at their in-situ condition exhibited similar volume changes during shear and identical friction angles. The results of shear tests of both of compacted soaked and unsoaked samples were identical. The collapse potential of dune soil is inversely proportional with the relative density. The minimum axial strain is observed when the samples are compacted to modified effort. The compression index of the compacted specimens is affected by moulding water content, while the rebound index is less sensitive.

Driver-Pressure-State-Impact-Response (DPSIR) analysis and risk assessment for soil compaction-A European perspective

NARCIS (Netherlands)

Schjønning, Per; Akker, van den J.J.H.; Keller, Thomas; Greve, M.H.; Lamandé, Mathieu; Simojoki, Asko; Stettler, Matthias; Arvidsson, Johan; Breuning-Madsen, Henrik

2015-01-01

Compaction of subsoil is a hidden but persistent damage that impairs a range of soil functions and ecosystem services. We analyzed the soil compaction issue in the Driver-Pressure-State-Impact-Response (DPSIR) context. The driving force (DPSIR-D) is the farmers' efforts to sustain economic

The use of gamma ray computed tomography to investigate soil compaction due to core sampling devices

International Nuclear Information System (INIS)

Pires, Luiz F.; Arthur, Robson C.J.; Correchel, Vladia; Bacchi, Osny O.S.; Reichardt, Klaus; Brasil, Rene P. Camponez do

2004-01-01

Compaction processes can influence soil physical properties such as soil density, porosity, pore size distribution, and processes like soil water and nutrient movements, root system distribution, and others. Soil porosity modification has important consequences like alterations in results of soil water retention curves. These alterations may cause differences in soil water storage calculations and matrix potential values, which are utilized in irrigation management systems. Because of this, soil-sampling techniques should avoid alterations of sample structure. In this work soil sample compaction caused by core sampling devices was investigated using the gamma ray computed tomography technique. A first generation tomograph with fixed source-detector arrangement and translation/rotational movements of the sample was utilized to obtain the images. The radioactive source is 241 Am, with an activity of 3.7 GBq, and the detector consists of a 3 in. x 3 in. NaI(Tl) scintillation crystal coupled to a photomultiplier tube. Soil samples were taken from an experimental field utilizing cylinders 4.0 cm high and 2.6 cm in diameter. Based on image analyses it was possible to detect compacted regions in all samples next to the cylinder wall due to the sampling system. Tomographic unit profiles of the sample permitted to identify higher values of soil density for deeper regions of the sample, and it was possible to determine the average densities and thickness of these layers. Tomographic analyses showed to be a very useful tool for soil compaction characterization and presented many advantages in relation to traditional methods. (author)

Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste

International Nuclear Information System (INIS)

Hamdi, Noureddine; Srasra, Ezzeddine

2013-01-01

Highlights: ► Examined the hydraulic conductivity evolution as function of dry density of Tunisian clay soil. ► Follow the hydraulic conductivity evolution at long-term of three clay materials using the waste solution (pH=2.7). ► Determined how compaction affects the hydraulic conductivity of clay soils. ► Analyzed the concentration of F and P and examined the retention of each soil. - Abstract: Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10 −10 , 2.08 × 10 −9 and 6.8 × 10 −10 m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m 3 ). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH = 2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m 3 ) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

Soil physical property changes at the North American long-term soil productivity study sites: 1 and 5 years after compaction

Science.gov (United States)

Deborah S. Page-Dumroese; Martin F. Jurgensen; Allan E. Tiarks; Felix Ponder; Felipe G. Sanchez; Robert L. Fleming; J. Marty Kranabetter; Robert F. Powers; Douglas M. Stone; John D. Elioff; D. Andrew. Scott

2006-01-01

The impact of forest management operations on soil physical properties is important to understand, since management can significantly change site productivity by altering root growth potential, water infiltration and soil erosion, and water and nutrient availability. We studied soil bulk density and strength changes as indicators of soil compaction before harvesting...

Effect of Adding Sugarcane Bagasse and Filter Cake and Wetting and Drying Cycles on Pre-Compaction Stress of Soil

Directory of Open Access Journals (Sweden)

Z Nemati

2018-03-01

Full Text Available Introduction The compaction of soil by agricultural equipment has become a matter of increasing concern because compaction of arable lands may reduce crop growth and yield, and it also has environmental impacts. In nature, soils could be compacted due to its own weights, external loads and internal forces as a result of wetting and drying processes. Soil compaction in sugarcane fields usually occurs due to mechanized harvesting operations by using heavy machinery in wet soils. Adding plant residues to the soil can improve soil structure. To improve soil physical quality of sugarcane fields, it might be suggested to add the bagasse and filter cake, which are the by-products of the sugar industry, to the soils. When a soil has been compacted by field traffic or has settled owing to natural forces, a threshold stress is believed to exist such that loadings inducing lower than the threshold cause little additional compaction, whilst loadings inducing greater stresses than the threshold cause much additional compaction. This threshold is called pre-compaction stress (σpc. The σpc is considered as an index of soil compactibility, the maximum pressure a soil has experienced in the past (i.e. soil management history, and the maximum major principal stress a soil can resist without major plastic deformation and compaction. Therefore, the main objective of this study was to investigate the effects of wetting and drying cycles, soil water content, residues type and percent on stress at compaction threshold (σpc. Materials and Methods In this research, the effect of adding sugarcane residues (i.e., bagasse and filter cake with two different rates (1 and 2% on pre-compaction stress (σpc in a silty clay loam soil which was prepared at two relative water contents of 0.9PL (PL= plastic limit, moist and 1.1PL (wet with or without wetting and drying cycles. This study was conducted using a factorial experiment in a completely randomized design with three

Statistical and Multifractal Evaluation of Soil Compaction in a Vineyard

Science.gov (United States)

Marinho, M.; Raposo, J. R.; Mirás Avalos, J. M.; Paz González, A.

2012-04-01

One of the detrimental effects caused by agricultural machines is soil compaction, which can be defined by an increase in soil bulk density. Soil compaction often has a negative impact on plant growth, since it reduces the macroporosity and soil permeability and increases resistance to penetration. Our research explored the effect of the agricultural machinery on soil when trafficking through a vineyard at a small spatial scale, based on the evaluation of the soil compaction status. The objectives of this study were: i) to quantify soil bulk density along transects following wine row, wheel track and outside track, and, ii) to characterize the variability of the bulk density along these transects using multifractal analysis. The field work was conducted at the experimental farm of EVEGA (Viticulture and Enology Centre of Galicia) located in Ponte San Clodio, Leiro, Orense, Spain. Three parallel transects were marked on positions with contrasting machine traffic effects, i.e. vine row, wheel-track and outside-track. Undisturbed samples were collected in 16 points of each transect, spaced 0.50 m apart, for bulk density determination using the cylinder method. Samples were taken in autumn 2011, after grape harvest. Since soil between vine rows was tilled and homogenized beginning spring 2011, cumulative effects of traffic during the vine growth period could be evaluated. The distribution patterns of soil bulk density were characterized by multifractal analysis carried out by the method of moments. Multifractality was assessed by several indexes derived from the mass exponent, τq, the generalized dimension, Dq, and the singularity spectrum, f(α), curves. Mean soil bulk density values determined for vine row, outside-track and wheel-track transects were 1.212 kg dm-3, 1.259 kg dm-3and 1.582 kg dm-3, respectively. The respective coefficients of variation (CV) for these three transects were 7.76%, 4.82% and 2.03%. Therefore mean bulk density under wheel-track was 30

Effects of subsoil compaction on hydraulic properties and preferential flow in a Swedish clay soil

DEFF Research Database (Denmark)

Mossadeghi-Björklund, M; Arvidsson, J.; Keller, Thomas

2016-01-01

in saturated hydraulic conductivity, air permeability and number of macropores at the second site. At this site, the traffic also significantly reduced the strength of preferential flow, presumably due to compaction-induced disruption of macropore continuity. In apparent contrast, some previous studies have shown......Soil compaction by vehicular traffic modifies the pore structure and soil hydraulic properties. These changes potentially influence the occurrence of preferential flow, which so far has been little studied. Our aim was to study the effect of compaction on soil hydraulic and transport properties...... transport derived from non-reactive tracer breakthrough curves and measurements of saturated hydraulic conductivity (Ks) and air permeability at the field moisture content (Ka). Although the traffic treatment did not cause any compaction effects at one of the two sites, it did result in significant reductions...

Structural changes in latosols of the cerrado region: II - soil compressive behavior and modeling of additional compaction

Directory of Open Access Journals (Sweden)

Eduardo da Costa Severiano

2011-06-01

Full Text Available Currently in Brazil, as in other parts of the world, the concern is great with the increase of degraded agricultural soil, which is mostly related to the occurrence of soil compaction. Although soil texture is recognized as a very important component in the soil compressive behaviors, there are few studies that quantify its influence on the structural changes of Latosols in the Brazilian Cerrado region. This study aimed to evaluate structural changes and the compressive behavior of Latosols in Rio Verde, Goiás, through the modeling of additional soil compaction. The study was carried out using five Latosols with very different textures, under different soil compaction levels. Water retention and soil compression curves, and bearing capacity models were determined from undisturbed samples collected on the B horizons. Results indicated that clayey and very clayey Latosols were more susceptible to compression than medium-textured soils. Soil compression curves at density values associate with edaphic functions were used to determine the beneficial pressure (σ b , i.e., pressure with optimal water retention, and critical pressure (σcrMAC, i.e., pressure with macroporosity below critical levels. These pressure values were higher than the preconsolidation pressure (σp, and therefore characterized as additional compaction. Based on the compressive behavior of these Latosols, it can be concluded that the combined preconsolidation pressure, beneficial pressure and critical pressure allow a better understanding of compression processes of Latosols.

Improvement of CBR and compaction characteristics of bauxite rich dispersive soils available in pakistan: a case study of khushab soil

International Nuclear Information System (INIS)

Batool, S.

2016-01-01

Dispersion of dispersive soil occurs when it comes in contact with water and clay particles deflocculate and disperse away from each other. Thus dispersive soils undergo erosion under low seepage velocity leading to instability problems of slopes and earth retaining structures. The amount of dispersion depends upon the mineralogy and geochemistry of clayey soil as well as the dissolved salts of the pore fluid. The dispersivity of the soil mainly depends on the amount of exchangeable sodium present in its formation. Under saturated conditions, the attractive forces are less than the repulsive forces and this will help the particles to disperse and go into colloidal suspension. The use of chemical stabilizers such as lime and cement to bind the clay particles and reduce the dispersivity of soil and to improve the compaction and CBR characteristics of bauxite rich dispersive soil present in Khushab district have been studied in this research. Soil behavior was studied after addition of 2%, 4%, 6% and 8% Lime and Cement, at optimum level of 6% for Lime and Cement; it has been observed that the CBR and compaction characteristics of Khushab soil have been improved. (author)

Soil compaction effects on growth and root traits of tobacco depend on light, water regime and mechanical stress

NARCIS (Netherlands)

Alameda, D.; Anten, N.P.R.; Villar, R.

2012-01-01

Soil compaction can strongly affect plant performance as many other stress factors. In nature, many combinations of different stress factors may be found. We expect that the effects of soil compaction may be different depending of the occurrence of other stress. This has not been fully investigated;

Differential Concentrations of some Nutrient Element in Forage of Corn (Zea mays L. as Affected by Organic Fertilizers and Soil Compaction

Directory of Open Access Journals (Sweden)

N. Najafi

2016-01-01

Full Text Available Soil compaction is one of the most important limiting factor for normal crop growth, because it reduces absorption by the plant. Application of organic fertilizers in agricultural soils can reduce the detrimental effects of soil compaction on plant growth and also supply some nutrients to plant. Thus, a factorial experiment was carried out in a randomized complete block design with three replications and 14 treatments to evaluate the effects of organic fertilizers in mitigating soil compaction. The first factor in this study was the source and amount of organic fertilizer at seven levels (control, farmyard manure, sewage sludge compost and municipal solid waste compost and each of organic fertilizers at two levels of 15 and 30 g/kg of soil. The second factor was soil compaction at two levels (bulk density of 1.2 and 1.7 g/cm3. To perform this experiment, 10 kg of dry soil was poured into special PVC pots and then seeds of single cross 704 corn were planted. At the end of the growth period, the corn shoot was harvested and concentrations of phosphorus (P, potassium (K, sodium (Na, iron (Fe, zinc (Zn, manganese (Mn, cadmium (Cd and lead (Pb were determined by dry ashing method. The results showed that concentrations of Cd and Pb in the shoot, related to the different treatments, were negligible. Concentrations of P, K, Fe, Mn and Zn in the corn shoot were increased significantly by application of farmyard manure, sewage sludge compost and municipal solid waste compost at both levels of soil compaction. However, Na concentration of shoot did not change significantly. Soil compaction significantly reduced P, Fe, Mn and Zn concentrations of corn shoot, but it affected concentrations of Na and K significantly. Application of organic fertilizers and increasing their levels reduced the negative effects of soil compaction on nutrients uptake by corn plant. This study showed that to improve forage corn nutrition, application of 15 or 30 g of farmyard

Soil properties and aspen development five years after compaction and forest floor removal

Science.gov (United States)

Douglas M. Stone; John D. Elioff

1998-01-01

Forest management activities that decrease soil porosity and remove organic matter have been associated with declines in site productivity. In the northern Lake States region, research is in progress in the aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forest type to determine effects of soil compaction and organic...

Effects of Density and Moisture Variation on Dynamic Deformation Properties of Compacted Lateritic Soil

Directory of Open Access Journals (Sweden)

Weizheng Liu

2016-01-01

Full Text Available A series of repeated load triaxial tests were conducted in this study to investigate the influences of compaction density and postcompaction moisture variation on the dynamic elastic modulus (Ed and plastic permanent strain (PPS of compacted lateritic soil. Specimens were compacted at optimum moisture content (OMC and three degrees of compaction (90%, 93%, and 96%. Then the specimens were dried or wetted to different moisture contents (OMC, OMC±3%, OMC±6%, and OMC+9% prior to testing for Ed and PPS. Results show that moisture content has greater influence on the Ed and PSS than compaction degree, and the increase in moisture content leads to a decrease of Ed and an increase of PPS. Furthermore, an empirical relationship between Ed and applied cyclic stress (σd is developed that incorporates density and moisture variations. Three different evolution types of PPS with number of load cycles, plastic stable, plastic creep, and incremental collapse, are identified as the increase of moisture content. In addition, the critical dynamic stress (σdc separating stable and unstable deformation is determined based on the shakedown concept. The envelope curves of σdc-moisture of lateritic soil with different degrees of compaction are also determined to provide reference for the pavement design.

Experimental study of collapsing properties of the compacted soil foundation of auto-road embankment

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Yushkov Boris Semenovich

2014-06-01

Full Text Available The loess collapsing soils are practically ubiquitously distributed in the Perm region. They occupy about 30% of the region area. The mass construction of buildings and structures of different purposes is conducted there. Design and construction of auto-roads on the collapsing soils by ensuring their strength and normal operation is one of the most important and difficult problems of the modern construction. It is recommended to eliminate collapsing properties of soils within the entire collapsing strata with the use of deep compaction by rammers and presoaking of foundation soils, including that with deepwater explosions, chemical or thermal fixing. Multi-year practice of construction on the collapsing soils in the regions of our country showed that during erection of the various structures the removal of the powerful loess soil collapsibility is achieved with the help of methods described above, each of which is selected on the basis of the conditions and possibilities of application. This article describes the following tasks: 1. Study and generalization of the available experience of road construction on the loess soils; 2. Zoning and classification (typing of the loess strata; 3. Selection of the engineering-geological factors influencing the choice of method for compacting collapsing soils; 4. General provisions for road construction on the collapsing soils.

Microbial community responses in forest mineral soil to compaction, organic matter removal, and vegetation control

Science.gov (United States)

Matt D. Busse; Samual E. Beattie; Robert F. Powers; Filpe G. Sanchez; Allan E. Tiarks

2006-01-01

We tested three disturbance hypotheses in young conifer plantations: H1: soil compaction and removal of surface organic matter produces sustained changes in microbial community size, activity, and structure in mineral soil; H2: microbial community characteristics in mineral soil are linked to the recovery of plant diversity...

Differences in Bacterial Diversity and Communities Between Glacial Snow and Glacial Soil on the Chongce Ice Cap, West Kunlun Mountains.

Science.gov (United States)

Yang, Guang Li; Hou, Shu Gui; Le Baoge, Ri; Li, Zhi Guo; Xu, Hao; Liu, Ya Ping; Du, Wen Tao; Liu, Yong Qin

2016-11-04

A detailed understanding of microbial ecology in different supraglacial habitats is important due to the unprecedented speed of glacier retreat. Differences in bacterial diversity and community structure between glacial snow and glacial soil on the Chongce Ice Cap were assessed using 454 pyrosequencing. Based on rarefaction curves, Chao1, ACE, and Shannon indices, we found that bacterial diversity in glacial snow was lower than that in glacial soil. Principal coordinate analysis (PCoA) and heatmap analysis indicated that there were major differences in bacterial communities between glacial snow and glacial soil. Most bacteria were different between the two habitats; however, there were some common bacteria shared between glacial snow and glacial soil. Some rare or functional bacterial resources were also present in the Chongce Ice Cap. These findings provide a preliminary understanding of the shifts in bacterial diversity and communities from glacial snow to glacial soil after the melting and inflow of glacial snow into glacial soil.

Persistent effects of subsoil compaction on pore size distribution and gas transport in a loamy soil

DEFF Research Database (Denmark)

Berisso, Feto Esimo; Schjønning, Per; Keller, T

2012-01-01

included four repeated wheelings with ∼10 Mg wheel loads. Water retention characteristics (WRC), air permeability (ka) and gas diffusivity (Ds/Do) were measured. A dual-porosity model fitted the WRC well, and there was a reduction in the volume of macropores >30 μm in compacted compared with control soil...... for all soil depths. Averaged for all sampling depths and also for some individual depths, both ka and Ds/Do were significantly reduced by compaction. Gas transport measurements showed that the experimental soil was poorly aerated, with local anoxic conditions at water regimes around field capacity in all...

Runoff and Erosion Effects after Prescribed Fire and Wildfire on Volcanic Ash-Cap Soils

Science.gov (United States)

P. R. Robichaud; F. B. Pierson; R. E. Brown

2007-01-01

After prescribed burns at three locations and one wildfire, rainfall simulations studies were completed to compare postfire runoff rates and sediment yields on ash-cap soil in conifer forest regions of northern Idaho and western Montana. The measured fire effects were differentiated by burn severity (unburned, low, moderate, and high). Results...

Impacts of forest harvest on active carbon and microbial properties of a volcanic ash cap soil in northern Idaho

Science.gov (United States)

Deborah S. Page-Dumroese; Matt D. Busse; Steven T. Overby; Brian D. Gardner; Joanne M. Tirocke

2015-01-01

Soil quality assessments are essential for determining impacts on belowground microbial community structure and function. We evaluated the suitability of active carbon (C), a rapid field test, as an indicator of soil biological quality in five paired forest stands (clear cut harvested 40 years prior and unharvested) growing on volcanic ash-cap soils in northern Idaho....

The use of 32P to study root growth of soybean as affected by soil compaction

International Nuclear Information System (INIS)

Sisworo, Elsje L.; Sisworo, Widjang H.; Syaukat, Sri Harti; Wemay, Johannis; Haryanto

1996-01-01

Two greenhouse and two field experiments have been conducted to study the effect of soil compaction on root and plant growth of soybean, by using 32 P in the form of carrier free KH 2 32 PO 4 solution. In the greenhouse experiment it was clearly shown that by increasing soil compaction the growth of roots and shoots was increasingly inhibited. The growth of roots was expressed in √% arcsin converted from 32 P activity (counts per minute, cpm) in the shoots and 32 P activity in the shoots (cpm) without convertion. Plant growth was expressed in plant height, number of leaves, dry weight of pods and shoots. In the field experiment, it was shown distinctively that root growth in the 15 cm soil depth was inhibited whith the increase of soil compaction. Similar with the greenhouse experiments the of plants of roots was expressed in cpm 32 P of roots, shoots, and pods, while, the growth of plants was expressed in plant height, number of pods, and dry weight of pods, seeds, and stover. (author). 19 refs, 4 tabs, 6 figs

In-situ studies on the performance of landfill caps (compacted soil liners, geomembranes, geosynthetic clay liners, capillary barriers)

International Nuclear Information System (INIS)

Melchior, S.

1997-01-01

Since 1986 different types of landfill covers have been studied in-situ on the Georgswerder landfill in Hamburg, Germany. Water balance data are available for eight years. The performance of different carriers has been measured by collecting the leakage on areas ranging from 100 m 2 to 500 m 2 . Composite liners with geomembranes performed best, showing no leakage. An extended capillary barrier also performed well. The performance of compacted soil liners, however, decreased severely within five years due to desiccation, shrinkage and plant root penetration (liner leakage now ranging from 150 mm/a to 200 mm/a). About 50 % of the water that reaches the surface of the liner is leaking through it. The maximum leakage rates have increased from 2 x 10 -10 m 3 m -2 s -1 to 4 x 10 -8 m 3 m -2 s -1 . Two types of geosynthetic clay liners (GCL) have been tested for two years now with disappointing results. The GCL desiccated during the first dry summer of the study. High percolation rates through the GCL were measured during the following winter (45 mm resp. 63 mm in four months). Wetting of the GCL did not significantly reduce the percolation rates

Water balance of two earthen landfill caps in a semi-arid climate

International Nuclear Information System (INIS)

Khire, M.V.; Benson, C.H.; Bosscher, P.J.

1997-01-01

Water balance data are presented that were obtained from two earthen cap test sections located in a semi-arid region. The test sections were constructed on a municipal solid waste landfill in East Wenatchee, Washington, USA. One test section represents a traditional resistive barrier, and is constructed with a compacted silty clay barrier 60 cm thick and a vegetated silty clay surface layer 15 cm thick. The other test section represents a capillary barrier and has a sand layer 75 cm thick overlain by a 15-cm-thick vegetated surface layer of silt. Extensive hydrological and meteorological data have been collected since November 1992. Unsaturated hydraulic properties of soils, hydrologic parameters, and vegetation have been extensively characterized. Results of the study show that capillary barriers can be effective caps in semi-arid and arid regions. They are also cheaper to construct and can perform better than traditional resistive barriers

X-ray CT and laboratory measurements on glacial till subsoil cores – assessment of inherent and compaction-affected soil structure characteristics

DEFF Research Database (Denmark)

Lamandé, Mathieu; Wildenschild, Dorthe; Berisso, Feto Esimo

2013-01-01

The aim of this study was to articulate the potential of medical computed tomographic (CT) scanning for analyzing soil structure (macroporosity, soil matrix density, number of macropores) and how these estimates compare with, and complement, traditional laboratory measurements (bulk density, total...... of visualization and traditional laboratory measurements proved valuable in identifying the persistent effects of subsoil compaction and the differences in soil structure among the two investigated subsoil layers. However, we recommend to systematically perform a sensitivity analysis to the segmentation threshold...... porosity, effective air-filled porosity, and air permeability). Undisturbed soil cores were sampled at two depths (0.35 and 0.7 m) in a long-term soil compaction experiment in southern Sweden 14 years after its establishment. Persistence of subsoil compaction was detectable by CT-estimated soil matrix...

Compaction of loamy soils due to tractor traffic in vineyards and orchards and its effect on infiltration in southern France

NARCIS (Netherlands)

Dijck, van S.J.E.; Asch, van T.W.J.

2002-01-01

Viticulture and fruit culture in Mediterranean areas demand frequent tractor traffic in vineyards and orchards for tillage and for the application of herbicides and pesticides, resulting in soil compaction. The aim of this study was to investigate theextent of soil compaction and its effect on

A market power model with price caps and compact DC power flow constraints

Energy Technology Data Exchange (ETDEWEB)

Zuwei Yu [Purdue University, West Lafayette, IN (United States). School of Industrial Engineering

2003-05-01

This paper presents a spatial gaming model with price caps for deregulated electricity markets. There has been heated debate on price caps that have been enforced in deregulated electricity markets. Opponents argue that price caps may send wrong economic signals while advocates argue that price caps are good for damping market power. This paper does not intend to take a stand in the argument. Given the fact that price caps are enforced in several deregulated regional electricity markets in the US, a logical step is to reflect this reality in gaining modeling. However, current gaining models have not included any price cap formulation. This paper is the first one to address the issue. DC power flow equations are used for representing the spatial nature of an electrical network. An algorithm is proposed to find a generalized Nash equilibrium under the enforcement of price caps based on the Kuhn-Tucker Vector Optimization Theorem. Case studies show the successful application of the model. The conclusion is that market power impact can be reduced under appropriate price caps. (author)

Anatomia radicular de milho em solo compactado Anatomy of maize roots in compacted soil

Directory of Open Access Journals (Sweden)

Anderson Cristian Bergamin

2010-03-01

Full Text Available O objetivo deste trabalho foi avaliar a relação entre a estrutura anatômica das raízes de milho e os atributos físicos de solo submetido a diferentes graus de compactação. O estudo foi realizado em campo, no Município de Dourados, MS, em Latossolo Vermelho distroférrico, textura muito argilosa. O delineamento experimental foi o de blocos ao acaso, com cinco repetições. O solo utilizado apresentava histórico de oito anos com plantio direto. A compactação adicional do solo foi realizada por meio de tráfego com trator, com uma (PDc1, duas (PDc2, quatro (PDc4 e seis passadas (PDc6 sucessivas, sobre toda a área da parcela. Houve aumento na razão entre o córtex e o cilindro vascular da raiz com o aumento na compactação do solo. Essa razão correlacionou-se negativamente com a macroporosidade e positivamente com a densidade do solo e com a resistência do solo à penetração. O grau de compactação afeta a anatomia radicular do milho, e a resistência do solo à penetração é o indicador físico que melhor expressa esse efeito.The objective of this work was to evaluate the relationship between maize root anatomy and physical attributes of soil subjected to levels of compaction. The experiment was carried out in field conditions, in Dourados, Mato Grosso do Sul state, Brazil, in a clayed Latossolo Vermelho (Rhodic Acrustox. A randomized complete block design was used, with five replicates. The soil was cultivated for eight years under no-tillage. The additional compaction of the soil was done by tractor traffic in one (PDc1, two (PDc2, four (PDc4 and six successive passes (PDc6, in the entire area of the experimental plots. Ratio between the cortex and vascular cylinder of the root increased with soil compaction. This ratio was negatively correlated to macroporosity, and positively to soil density and soil penetration resistance. Soil compaction level affects the anatomy of maize roots, and its penetration resistance is the best

Effect of class F fly ash on fine sand compaction through soil stabilization.

Science.gov (United States)

Mahvash, Siavash; López-Querol, Susana; Bahadori-Jahromi, Ali

2017-03-01

This paper presents the results of an experimental investigation carried out to evaluate the effect of fly ash (FA) on fine sand compaction and its suitability as a material for embankments. The literature review demonstrates the lack of research on stabilization of sandy material using FA. The study is concerned with the role of FA content in stabilized soil physical characteristics. The main aim of this paper is to determine the optimum quantity of FA content for stabilization of this type of soil. This is achieved through particle size distribution and compaction (standard proctor) tests. The sand was stabilized with three proportions of FA (5%, 10% and 15%) and constant cement content of 3% was used as an activator. For better comparison, the sand was also stabilized by 3% cement only so that the effect of FA could be observed more clearly. The results were in line with the literature for other types of soil, i.e. as the % of FA increases, reduction in maximum dry density and higher optimum moisture content were observed.

Effect of class F fly ash on fine sand compaction through soil stabilization

Directory of Open Access Journals (Sweden)

Siavash Mahvash

2017-03-01

Full Text Available This paper presents the results of an experimental investigation carried out to evaluate the effect of fly ash (FA on fine sand compaction and its suitability as a material for embankments. The literature review demonstrates the lack of research on stabilization of sandy material using FA. The study is concerned with the role of FA content in stabilized soil physical characteristics. The main aim of this paper is to determine the optimum quantity of FA content for stabilization of this type of soil. This is achieved through particle size distribution and compaction (standard proctor tests. The sand was stabilized with three proportions of FA (5%, 10% and 15% and constant cement content of 3% was used as an activator. For better comparison, the sand was also stabilized by 3% cement only so that the effect of FA could be observed more clearly. The results were in line with the literature for other types of soil, i.e. as the % of FA increases, reduction in maximum dry density and higher optimum moisture content were observed.

Swelling and collapse of compacted soils to be used as earth dam cores

Directory of Open Access Journals (Sweden)

Bardanis Michael

2016-01-01

Full Text Available The mechanical behaviour of fine-grained soil materials to be used as impermeable cores for earth dams has been extensively studied by numerous researchers. The required properties of these materials have also been very well described by standards and specifications. Yet, more than often it is required to assess their swelling/collapse potential, especially at various vertical stresses, as a means to estimate their volume changes upon inundation which is going to be caused by filling the dam reservoir. In the paper, experimental results of five different soils are presented. The soils tested ranged from non-plastic silty sands with clay to medium plasticity clayey silts that were compacted in conditions dry, at and wet of optimum moisture content as derived from standard compaction energy Proctor tests, then subjected to one-dimensional loading conditions and then inundated. The vertical stress was up to 7.6 MPa. The experimental results are categorized according to initial moisture content relative to Proctor optimum and indicate expected magnitudes of strains due to inundation for various grain-size distributions and plasticities.

Diffusion through statically compacted clay

International Nuclear Information System (INIS)

Ho, C.L.; Shebl, M.A.A.

1994-01-01

This paper presents experimental work on the effect of compaction on contaminant flow through clay liners. The experimental program included evaluation of soil properties, compaction, permeability and solute diffusion. A permeameter was built of non reactive materials to test samples compacted at different water contents and compactive efforts. The flow of a permeating solute, LiCl, was monitored. Effluent samples were collected for solute concentration measurements. The concentrations were measured by performing atomic adsorption tests. The analyzed results showed different diffusion characteristics when compaction conditions changed. At each compactive effort, permeability decreased as molding water content increased. Consequently, transit time (measured at relative concentration 50%) increased and diffusivity decreased. As compactive effort increased for soils compacted dry of optimum, permeability and diffusion decreased. On the other hand, as compactive effort increased for soils compacted wet of optimum, permeability and diffusivity increased. Tortuosity factor was indirectly measured from the diffusion and retardation rate. Tortuosity factor also decreased as placement water content was increased from dry of optimum to wet of optimum. Then decreases were more pronounced for low compactive effort tests. 27 refs., 7 figs., 5 tabs

Effects of traffic-induced soil compaction on crop growth and soil properties

Science.gov (United States)

Baibay, Amélia; Ren, Lidong; D'Hose, Tommy; De Pue, Jan; Ruysschaert, Greet; Cornelis, Wim

2017-04-01

Traffic-induced soil compaction on arable soils constitutes a major threat for agricultural productivity and the environmental quality of the soil, water and atmosphere. The objective of this work is to evaluate a set of prevention strategies for agricultural traffic under real farming conditions. To that end, a one-pass traffic experiment was conducted near Ghent, Belgium in winter 2015 on a sandy loam (haplic Luvisol; 43% sand, 47% silt, 10% clay). Winter rye (Secale cereale L.), which promotes the removal of residual soil nitrogen and thus reduces the potential for nitrogen leaching, was sown as cover crop using different tractor and weather settings on different field lanes: dry (D, 0.16 m3 m-3) or wet (W, 0.20-0.23 m3 m-3) conditions, normal (N, 65 cm width, axle load 8520 kg) or wide (W, 90 cm width, axle load 8520 kg) tires and high (HP, 1.4 bars for N, 1.0 bar for W) or low (LP, 1.0 bar for N, 0.5 bar for W) inflation pressure. Subsequently, crop biomass, root density and a set of hydrophysical properties (penetration resistance, saturated hydraulic conductivity and water retention at 15, 35 and 55 cm depth) were measured. Bulk density, soil quality indicators (such as air capacity) and the pore size distribution were also calculated. Results showed significant biomass reduction (p crop growth, worse under wet conditions, but the choice of tires did not prove to have an effect. Observations on the hydrophysical properties were more mitigated, as expected: distinct differences are primarily found under controlled lab conditions or after several passes. Moreover, high moisture conditions could not be obtained for the wet experiment, which never exceeded field capacity, conceived as threshold. Nevertheless, penetration resistance profiles indicated a plough pan about 40 cm depth, witness of previous agricultural operations on the field, and high values (3.5 to 4 MPa) were found in the subsoil too. Moreover, bulk densities were higher for all treatments (up to

Long-term effects of deep soil loosening on root distribution and soil physical parameters in compacted lignite mine soils

Science.gov (United States)

Badorreck, Annika; Krümmelbein, Julia; Raab, Thomas

2015-04-01

Soil compaction is a major problem of soils on dumped mining substrates in Lusatia, Germany. Deep ripping and cultivation of deep rooting plant species are considered to be effective ways of agricultural recultivation. Six years after experiment start, we studied the effect of initial deep soil loosening (i.e. down to 65 cm) on root systems of rye (Secale cereale) and alfalfa (Medicago sativa) and on soil physical parameters. We conducted a soil monolith sampling for each treatment (deep loosened and unloosened) and for each plant species (in three replicates, respectively) to determine root diameter, length density and dry mass as well as soil bulk density. Further soil physical analysis comprised water retention, hydraulic conductivity and texture in three depths. The results showed different reactions of the root systems of rye and alfalfa six years after deep ripping. In the loosened soil the root biomass of the rye was lower in depths of 20-40 cm and the root biomass of alfalfa was also decreased in depths of 20-50 cm together with a lower root diameter for both plant species. Moreover, total and fine root length density was higher for alfalfa and vice versa for rye. The soil physical parameters such as bulk density showed fewer differences, despite a higher bulk density in 30-40cm for the deep loosened rye plot which indicates a more pronounced plough pan.

Changes in soil physical and chemical properties following organic matter removal and compaction: 20-year response of the aspen Lake-States Long Term Soil Productivity installations

Science.gov (United States)

Robert A. Slesak; Brian J. Palik; Anthony W. D' Amato; Valerie J. Kurth

2017-01-01

Soil functions that control plant resource availability can be altered by management activities such as increased organic matter (OM) removal and soil compaction during forest harvesting. The Long Term Soil Productivity study was established to evaluate how these practices influence soil and site productivity using experimental treatments that span a range of forest...

Soil compaction: alterations in physical, chemical and biological attributes in a fluvic neosoil; Compactacao do solo: alteracoes nos atributos fisicos, quimicos e biologicos de um neossolo fluvico

Energy Technology Data Exchange (ETDEWEB)

Viana, Eliane Ferreira

2004-12-15

The efficient management of soil proposes the correct utilization of agricultural practices to minimize the loss of structure, compaction, and nutrient losses in the soil, which are the main causes of its degradation. Such concerns reside in the fact that the impact from compaction can also be related to the soil capacity for losing carbon. This effect has strong influence on CO{sub 2} emissions to the atmosphere. On the other hand, induced mutation, a valuable tool for the development of genetic materials, that is tolerant to environmental adversities, can be helpful in the adaptation of crops in compacted soils. This study was conducted to evaluate isolated and combined effects of compaction, water content and organic amendments in soil respiration. Also it investigates the development of cowpea (V. unguiculata, L. Walp] var. IPA 206, in a Fluvic Neosoil, artificially compacted, with different fertilizer materials added (cowdung, NPK, organomineral I, and organomineral II). Also it evaluates the development of cowpea when the seeds were submitted to gamma irradiation ({sup 60}Co) and cultivated in compacted and non compacted soil, under greenhouse conditions, for 60 days. The isolated addition of spent coffee powder and marine algae to the soil increased the CO{sub 2} evolution from soil, reflecting variations in dynamics of the heterotrophic soil microbiota. CO{sub 2} evolution decreased with the increase in soil density, showing reductions in aeration. The values presented were found to be low in the treatment without addition of these materials (control) and showed them to be significantly increased in the treatments that received such residues, all over the incubation period. Plant height, root length, shoot dry matter production and dry matter of nodules diminished with the increase in soil density. The incorporation of the organomineral mixtures I and II to the artificially compacted soil, showed an increase in plant height, and root length, suggesting the

Remote Sensing-based Models of Soil Vulnerability to Compaction and Erosion from Off-highway Vehicles

Science.gov (United States)

Villarreal, M. L.; Webb, R. H.; Norman, L.; Psillas, J.; Rosenberg, A.; Carmichael, S.; Petrakis, R.; Sparks, P.

2014-12-01

Intensive off-road vehicle use for immigration, smuggling, and security of the United States-Mexico border has prompted concerns about long-term human impacts on sensitive desert ecosystems. To help managers identify areas susceptible to soil erosion from vehicle disturbances, we developed a series of erosion potential models based on factors from the Revised Universal Soil Loss Equation (RUSLE), with particular focus on the management factor (P-factor) and vegetation cover (C-factor). To better express the vulnerability of soils to human disturbances, a soil compaction index (applied as the P-factor) was calculated as the difference in saturated hydrologic conductivity (Ks) between disturbed and undisturbed soils, which was then scaled up to remote sensing-based maps of vehicle tracks and digital soils maps. The C-factor was improved using a satellite-based vegetation index, which was better correlated with estimated ground cover (r2 = 0.77) than data derived from regional land cover maps (r2 = 0.06). RUSLE factors were normalized to give equal weight to all contributing factors, which provided more management-specific information on vulnerable areas where vehicle compaction of sensitive soils intersects with steep slopes and low vegetation cover. Resulting spatial data on vulnerability and erosion potential provide land managers with information to identify critically disturbed areas and potential restoration sites where off-road driving should be restricted to reduce further degradation.

Densification behavior of aluminum alloy powder mixed with zirconia powder inclusion under cold compaction

International Nuclear Information System (INIS)

Ryu, Hyun Seok; Lee, Sung Chul; Kim, Ki Tae

2002-01-01

Densification behavior of composite powders was investigated during cold compaction. Experimental data were obtained for aluminum alloy powder mixed with zirconia powder inclusion under triaxial compression. The cap model with constraint factors was implemented into a finite element program(ABAQUS) to simulate compaction responses of composite powders during cold compaction. Finite element results were compared with experimental data for densification behavior of composite powders under cold isostatic pressing and die compaction. The agreements between experimental data and finite element calculations from the cap model with constraint factors were good

METHOD OF ESTIMATING THE TRAVEL TIME OF NONINTERACTING SOLUTES THROUGH COMPACTED SOIL MATERIAL

Science.gov (United States)

The pollutant travel time through compacted soil material (i.e., when a pollutant introduced at the top first appears at the bottom) cannot be accurately predicted from the permeability (saturated hydraulic conductivity) alone. The travel time is also dependent on the effective p...

Operational methods for minimising soil compaction and diffuse pollution risk from wheelings in winter cereals

Science.gov (United States)

Jackson, Bob; Silgram, Martyn; Quinton, John

2010-05-01

Recent UK government-funded research has shown that compacted, unvegetated tramlines wheelings can represent an important source and transport pathway, which can account for 80% of surface runoff, sediment and phosphorus losses to edge-of-field from cereals on moderate slopes. For example, recent research found 5.5-15.8% of rainfall lost as runoff, and losses of 0.8-2.9 kg TP/ha and 0.3-4.8 T/ha sediment from tramline wheelings. When compaction was released by shallow cultivation, runoff was reduced to 0.2-1.7% of rainfall with losses of 0.0-0.2 kg TP/ha and 0.003-0.3 T/ha sediment respectively i.e. close to reference losses from control areas without tramlines. Recent independent assessments using novel tracer techniques have also shown that tramline wheelings can represent important sediment sources at river catchment scale. In response to these latest findings, a new project is now underway investigating the most cost-effective and practical ways of operationalising methods for managing tramline wheelings in autumn-sown cereal systems to reduce the risk of soil compaction from the autumn spray operation and the associated risk of surface runoff and diffuse pollution loss of sediment, phosphorus and nitrogen to edge of field. Research is focusing on the over-winter period when soils are close to field capacity and the physical protection of the soil surface granted by growing crop is limited. This paper outlines this new multi-disciplinary project and associated methodologies, which include hillslope-scale event-based evaluations of the effectiveness of novel mitigation methods on surface runoff and diffuse pollution losses to edge of field, assessments of the economic and practical viability of mitigation methods, and modelling the impact on water quality of implementation of the most promising techniques at both farm and catchment scale. The study involves a large consortium with 20 partners, including many industrial organisations representing tractor, crop

Development of Soil Compaction Analysis Software (SCAN Integrating a Low Cost GPS Receiver and Compactometer

Directory of Open Access Journals (Sweden)

Dongha Lee

2012-02-01

Full Text Available A software for soil compaction analysis (SCAN has been developed for evaluating the compaction states using the data from the GPS as well as a compactometer attached on the roller. The SCAN is distinguished from other previous software for intelligent compaction (IC in that it can use the results from various types of GPS positioning methods, and it also has an optimal structure for remotely managing the large amounts of data gathered from numerous rollers. For this, several methods were developed: (1 improving the accuracy of low cost GPS receiver’s positioning results; (2 modeling the trajectory of a moving roller using a GPS receiver’s results and linking it with the data from the compactometer; and (3 extracting the information regarding the compaction states of the ground from the modeled trajectory, using spatial analysis methods. The SCAN was verified throughout various field compaction tests, and it has been confirmed that it can be a very effective tool in evaluating field compaction states.

Use of a combined penetrometer-TDR moisture probe for soil compaction studies

International Nuclear Information System (INIS)

Pedro Vaz, C.M.

2004-01-01

Soil mechanical strength is an important soil parameter that affects root growth and water movement, and controls nutrient and contaminant transport below the rooting zone. The most common way to assess soil strength is by using a soil penetrometer, which characterizes the force needed to drive a cone of specific size into the soil. The measured penetration resistance (PR) depends on such soil properties as bulk density, water content and potential, texture, aggregation, cementation and mineralogy. Soil scientists have related changes in PR as caused by tillage, traffic or soil genetic pans to root growth, crop yields and soil physical properties. For example, correlation between PR and crop root growth and water and nutrient exploration have been obtained, and cone penetrometers have been used extensively in soil science studies to identify natural and induced compacted layers or to predict related soil properties. Many studies have been conducted to understand the influence of bulk density and water content on PR in the laboratory and, from which both empirical and theoretical relationships were obtained. From the many different models that have been introduced to test these relationships (polynomial, exponential, power and linear equations), it is suggested that either the power or exponential equations are the most adequate. Using dimensional analysis techniques, it was suggested a power exponential equation for prediction of the PR for a silt loam soil, but also suggested additional experimental work for its validation. However, many referenced studies lack accurate and representative data, because PR is a highly variable soil property, whereas it is usually determined from local small-scale measurements. Hence, difficulties in relating PR with other soil parameters can be attributed mostly to soil spatial variability, because available measurement techniques prevent determination of the different soil attributes at the same spatial location. To improve on the

Soil compaction effects of forwarding and its relationship with 6- and 8-wheel drive machines

Science.gov (United States)

Fernando Seixas; Tim. McDonald

1997-01-01

A study was done to determine the impact, if any, of a range of drive train options on the soil compaction effects of forwarders. The purpose of the study was to evaluate the cost of optional forwarder equipment versus its ability to reduce detrimental soil physical property changes. Tests were done on forwarders equipped with wide and narrow tires, rear steel tracks,...

Biofilm treatment of soil for waste containment and remediation

International Nuclear Information System (INIS)

Turner, J.P.; Dennis, M.L.; Osman, Y.A.; Chase, J.; Bulla, L.A.

1997-01-01

This paper examines the potential for creating low-permeability reactive barriers for waste treatment and containment by treating soils with Beijerinckia indica, a bacterium which produces an exopolysaccharide film. The biofilm adheres to soil particles and causes a decrease in soil hydraulic conductivity. In addition, B. Indica biodegrades a variety of polycyclic aromatic hydrocarbons and chemical carcinogens. The combination of low soil hydraulic conductivity and biodegradation capabilities creates the potential for constructing reactive biofilm barriers from soil and bacteria. A laboratory study was conducted to evaluate the effects of B. Indica on the hydraulic conductivity of a silty sand. Soil specimens were molded with a bacterial and nutrient solution, compacted at optimum moisture content, permeated with a nutrient solution, and tested for k sat using a flexible-wall permeameter. Saturated hydraulic conductivity (k sat ) was reduced from 1 x 10 -5 cm/sec to 2 x 10 -8 cm/sec: by biofilm treatment. Permeation with saline, acidic, and basic solutions following formation of a biofilm was found to have negligible effect on the reduced k sat , for up to three pore volumes of flow. Applications of biofilm treatment for creating low-permeability reactive barriers are discussed, including compacted liners for bottom barriers and caps and creation of vertical barriers by in situ treatment

Microbial biomass and bacterial functional diversity in forest soils: effects of organic matter removal, compaction, and vegetation control

Science.gov (United States)

Qingchao Li; H. Lee Allen; Arthur G. Wollum

2004-01-01

The effects of organic matter removal, soil compaction, and vegetation control on soil microbial biomass carbon, nitrogen, C-to-N ratio, and functional diversity were examined in a 6-year loblolly pine plantation on a Coastal Plain site in eastern North Carolina, USA. This experimental plantation was established as part of the US Forest Service's Long Term Soil...

Compacting coastal plain soils changes midrotation loblolly pine allometry by reducing root biomass

Science.gov (United States)

Kim H. Ludovici

2008-01-01

Factorial combinations of soil compaction and organic matter removal were replicated at the Long Term Site Productivity study in the Croatan National Forest, near New Bern, North Carolina, USA. Ten years after planting, 18 preselected loblolly pine (Pinus taeda L.) trees were destructively harvested to quantify treatment effects on total above- and...

SWEET SORGHUM PERFORMANCE AFFECTED BY SOIL COMPACTION AND SOWING TIME AS A SECOND CROP IN THE BRAZILIAN CERRADO

Directory of Open Access Journals (Sweden)

Wellingthon da Silva Guimarães Júnnyor

2015-12-01

Full Text Available ABSTRACT Increasing attention has recently been given to sweet sorghum as a renewable raw material for ethanol production, mainly because its cultivation can be fully mechanized. However, the intensive use of agricultural machinery causes soil structural degradation, especially when performed under inadequate conditions of soil moisture. The aims of this study were to evaluate the physical quality of aLatossolo Vermelho Distroférrico (Oxisol under compaction and its components on sweet sorghum yield forsecond cropsowing in the Brazilian Cerrado (Brazilian tropical savanna. The experiment was conducted in a randomized block design, in a split plot arrangement, with four replications. Five levels of soil compaction were tested from the passing of a tractor at the following traffic intensities: 0 (absence of additional compaction, 1, 2, 7, and 15 passes over the same spot. The subplots consisted of three different sowing times of sweet sorghum during the off-season of 2013 (20/01, 17/02, and 16/03. Soil physical quality was measured through the least limiting water range (LLWR and soil water limitation; crop yield and technological parameters were also measured. Monitoring of soil water contents indicated a reduction in the frequency of water content in the soil within the limits of the LLWR (Fwithin as agricultural traffic increased (T0 = T1 = T2>T7>T15, and crop yield is directly associated with soil water content. The crop sown in January had higher industrial quality; however, there was stalk yield reduction when bulk density was greater than 1.26 Mg m-3, with a maximum yield of 50 Mg ha-1 in this sowing time. Cultivation of sweet sorghum as a second crop is a promising alternative, but care should be taken in cultivation under conditions of pronounced climatic risks, due to low stalk yield.

Effect of Subsoil Compaction on Hydraulic Parameters

DEFF Research Database (Denmark)

Iversen, Bo Vangsø; Berisso, Feto Esimo; Schjønning, Per

Soil compaction is a major threat to sustainable soil quality and is increasing since agricultural machinery is becoming heavier and is used more intensively. Compaction not only reduces pore volume, but also modifies the pore connectivity. The inter-Nordic research project POSEIDON (Persistent...... effects of subsoil compaction on soil ecological services and functions) put forward the hypothesis that due to a decrease in the hydraulic conductivity in the soil matrix, compaction increases the frequency of preferential flow events in macropores and therefore increases the leaching of otherwise....... In the field the near-saturated hydraulic conductivity was measured with a tension infiltrometer in the same treatments at a depth of 30 cm. In the laboratory saturated and near-saturated hydraulic conductivity and the bulk density were measured as well. Also, macropores in the large soil cores were made...

The Estimation of Compaction Parameter Values Based on Soil Properties Values Stabilized with Portland Cement

Science.gov (United States)

Lubis, A. S.; Muis, Z. A.; Pasaribu, M. I.

2017-03-01

The strength and durability of pavement construction is highly dependent on the properties and subgrade bearing capacity. This then led to the idea of the selection methods to estimate the density of the soil with the proper implementation of the system, fast and economical. This study aims to estimate the compaction parameter value namely the maximum dry unit weight (γd max) and optimum moisture content (wopt) of the soil properties value that stabilized with Portland Cement. Tests conducted in the laboratory of soil mechanics to determine the index properties (fines and liquid limit) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) between 0-15% then mixed with Portland Cement (PC) with variations of 2%, 4%, 6%, 8% and 10%, each 10 samples. The results showed that the maximum dry unit weight (γd max) and wopt has a significant relationship with percent fines, liquid limit and the percentation of cement. Equation for the estimated maximum dry unit weight (γd max) = 1.782 - 0.011*LL + 0,000*F + 0.006*PS with R2 = 0.915 and the estimated optimum moisture content (wopt) = 3.441 + 0.594*LL + 0,025*F + 0,024*PS with R2 = 0.726.

Structure of the radio emission from the NGC 1579/LkH. cap alpha. 101 region

Energy Technology Data Exchange (ETDEWEB)

Brown, R L [National Radio Astronomy Observatory, Charlottesville, Va. (USA); Broderick, J J; Knapp, G R

1976-06-01

Radio-frequency observations at 3.7 and 11 cm of the NGC 1579/LkH..cap alpha..101 region show that the radio emission arises in a compact, < 1'' core concentric with a more extended approximately 1' emission region. At these wavelengths the compact component is optically thick, with a spectrum increasing as ..nu.., whereas the extended region is optically thin and contributes at least 80 per cent of the total flux density. LkH..cap alpha..101 appears to be the source of excitation for all of the radio emission; this result, together with the total infrared luminosity, suggests that an appropriate spectral classification for LkH..cap alpha..101 is B1 IIe.

State-of-the-art synthetic membrane for capping landfills

International Nuclear Information System (INIS)

Kriofske, K.P.; Gagle, D.W.

1991-01-01

Very Low Density Polyethylene (VLDPE) has emerged as a superior capping material for landfill closures. Landfills must be capped by a material which will undergo substantial deformation in areas of localized settlement prior to rupture. Methane and hydrogen sulfide gases must be contained and directed to collection points without permeating the landfill cap. Vegetative growth in the cover sods will be protected by the gas impermeability of the geosynthetic membrane. VLDPE compounded with carbon black is minimally affected by radiation and is inert to ultraviolet rays. This property sustains VLDPE's ability to retard gas permeation at levels superior to other geosynthetics. Cover soil stability on long cap slopes in all weather conditions is crucial. It has been demonstrated in the laboratory and in full-scale, on-site test conditions that VLDPE exhibits friction characteristics equaling or exceeding other synthetics used for this purpose without diminishing physical and chemical properties. Large-scale, multiaxial stress tests have demonstrated the ability of VLDPE to deflect substantially in all directions of a potential settlement area. Only PVC can equal the elastic deformation properties of VLDPE, but PVC is more gas-permeable susceptible to degradation due to natural soil radiation or ultraviolet light and heat. Test results are presented to illustrate these points. The geosynthetic cap membrane must prevent water percolation into the landfill to prevent the formation of hazardous leachates. The use of a VLDPE cap reduces the depth of cap soils, thus increasing landfill volume. The economics and reduction in long-term liabilities of closure costs are enhanced by the use of VLDPE in the cap system. Since the expected half-life of polyethylene exceeds hundreds of years, the inclusion of VLDPE in the cap system will provide pollution security for many generations

Effects of organic matter removal and soil compaction on fifth-year mineral soil carbon and nitrogen contents for sites across the United States and Canada

Science.gov (United States)

Felipe G. Sanchez; Allan E. Tiarks; J. Marty Kranabetter; Deborah S. Page-Dumroese; Robert F. Powers; Paul T. Sanborn; William K. Chapman

2006-01-01

This study describes the main treatment effects of organic matter removal and compaction and a split-plot effect of competition control on mineral soil carbon (C) and nitrogen (N) pools. Treatment effects on soil C and N pools are discussed for 19 sites across five locations (British Columbia, Northern Rocky Mountains, Pacific Southwest, and Atlantic and Gulf coasts)...

Negligible effects of severe organic matter removal and soil compaction on loblolly pine growth over 10 years

Science.gov (United States)

Felipe G. Sanchez; D. Andrew Scott; Kim H. Ludovici

2006-01-01

The long-term soil productivity (LTSP) study was initiated to examine the effect of soil porosity and organic matter (OM) levels on net primary productivity (NPP). The study design calls for three levels of OM removal (bole, whole tree and whole tree plus forest floor) and three levels of compaction (none, moderate and severe) being imposed on harvested sites prior to...

Compactação causada pelo tráfego de trator em diferentes manejos de solo = Soil compaction induced by tractor traffic in different soil managements

Directory of Open Access Journals (Sweden)

João Paulo Arantes Rodrigues da Cunha

2009-07-01

Full Text Available O objetivo deste trabalho foi avaliar a compactação do solo causada pelo tráfego de trator, em um Latossolo Vermelho distroférrico submetido a diferentes tipos de preparo. O delineamento experimental utilizado foi o de blocos casualizados, com arranjo de parcelassubdivididas, considerando os tipos de preparo de solo como tratamentos principais e o número de passadas do trator como tratamentos secundários. Como tratamentos de preparo de solo, além de uma testemunha sem movimentação, foram avaliados: aração com 18 cmde profundidade, aração com 18 cm de profundidade, seguida de gradagem a 10 cm e subsolagem a 40 cm de profundidade. Após o preparo, foi avaliada a resistência do solo à penetração, por meio de um penetrômetro eletrônico, antes da passagem do trator e apósuma, três, cinco e sete vezes a passagem do trator na mesma linha de tráfego. Também se realizou a avaliação de densidade do solo. Concluiu-se que quanto maior a pulverização do solo, maior foi o potencial de compactação. Solos recentemente arados e gradeados forammais susceptíveis à compactação do que solos somente arados ou subsolados. O efeito do tráfego do trator concentrou-se principalmente na camada superficial, e a primeira passada foi a que mais provocou compactação do solo.The objective of this work was to evaluate soil compaction induced bytractor traffic in a Red Latosol (Typic Acrustox, submitted to different soil managements. The experiment was arranged in a subdivided parcel scheme, with types of soil tillage as theprimary soil treatments and the number of tractor passes as secondary treatments. In addition to a control treatment without soil tillage, the treatments were: tilling to a depth of 18 cm, a tilling to a depth of 18 cm followed by harrow use at a depth of 10 cm, and a 40-cm deep subsoil tilling. After preparing the parcels, soil penetration resistance was measured with an electronic penetrometer, before tractor passes and

Temperature evolution during compaction of pharmaceutical powders.

Science.gov (United States)

Zavaliangos, Antonios; Galen, Steve; Cunningham, John; Winstead, Denita

2008-08-01

A numerical approach to the prediction of temperature evolution in tablet compaction is presented here. It is based on a coupled thermomechanical finite element analysis and a calibrated Drucker-Prager Cap model. This approach is capable of predicting transient temperatures during compaction, which cannot be assessed by experimental techniques due to inherent test limitations. Model predictions are validated with infrared (IR) temperature measurements of the top tablet surface after ejection and match well with experiments. The dependence of temperature fields on speed and degree of compaction are naturally captured. The estimated transient temperatures are maximum at the end of compaction at the center of the tablet and close to the die wall next to the powder/die interface.

Compaction of an Oxisol and chemical composition of palisadegrass

Directory of Open Access Journals (Sweden)

Eurico Lucas de Sousa Neto

2013-08-01

Full Text Available Compaction is an important problem in soils under pastoral land use, and can make livestock systems unsustainable. The objective of this research was to study the impact of soil compaction on yield and quality of palisade (UROCHLOA BRIZANTHA cv. Marandu. The experiment was conducted on an Oxisol in the State of Mato Grosso, Brazil. Treatments consisted of four levels of soil compaction: no compaction (NC, slight compaction (SC, medium compaction (MC and high compaction (HC. The following soil properties were evaluated (layers 0-0.05 and 0.05-0.10 m: aggregate size distribution, bulk density (BD, macroporosity, microporosity, total porosity (TP, relative compaction (RC, and the characteristics of crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF and dry matter yield (DMY of the forage. Highly compacted soil had high BD and RC, and low TP (0-0.05 m. Both DMY and CP were affected by HC, and both were strongly related to BD. Higher DMY (6.96 Mg ha-1 and CP (7.8 % were observed in the MC treatment (BD 1.57 Mg m-3 and RC 0.91 Mg m-3, in 0-0.05 m. A high BD of 1.57 Mg m-3 (0-0.05 m did not inhibit plant growth. The N concentration in the palisade biomass differed significantly among compaction treatments, and was 8.72, 11.20, 12.48 and 10.98 g kg-1 in NC, SC, MC and HC treatments, respectively. Increase in DMY and CP at the MC level may be attributed to more absorption of N in this coarse-textured soil.

Interaction of the Bored Sand and Gravel Drain Pile with the Surrounding Compacted Loam Soil and Foundation Raft Taking into Account Rheological Properties of the Loam Soil and Non-Linear Properties of the Drain Pile

Science.gov (United States)

Ter-Martirosyan, Z. G.; Ter-Martirosyan, A. Z.; Anzhelo, G. O.; Buslov, A. S.

2018-01-01

The task of the interaction of the sand and gravel drain pile with the surrounding loam soil after its preliminary deep compaction and formation of the composite ground cylinder from the drain pile and surrounding compacted loam soil (cells) is considered in the article. It is seen that the subsidence and carrying capacity of such cell considerably depends on physical and mechanical properties of the compacted drain piles and surrounding loam soil as well as their diameter and intercellular distance. The strain-stress state of the cell is considered not taking into account its component elements, but taking into account linear and elastic-plastic properties of the drain pile and creep flow of the surrounding loam soil. It is stated that depending on these properties the distribution and redistribution of the load on a cell takes place from the foundation raft between the drain pile and surrounding soil. Based on the results of task solving the formulas and charts are given demonstrating the ratio of the load between the drain pile and surrounding loam soil in time.

Effects of vegetation and soil-surface cover treatments on the hydrologic behavior of low-level waste trench caps

International Nuclear Information System (INIS)

Lopez, E.A.; Barnes, F.J.; Antonio, E.J.

1988-01-01

Preliminary results are presented on a three-year field study at Los Alamos National Laboratory to evaluate the influence of different low-level radioactive waste trench cap designs on water balance under natural precipitation. Erosion plots having two different vegetative covers (shrubs and grasses) and with either gravel-mulched or unmulched soil surface treatments have been established on three different soil profiles on a decommissioned waste site. Total runoff and soil loss from each plot is measured after each precipitation event. Soil moisture is measured biweekly while plant canopy cover is measured seasonally. Preliminary results from the first year show that the application of a gravel mulch reduced runoff by 73 to 90%. Total soil loss was reduced by 83 to 93% by the mulch treatment. On unmulched plots, grass cover reduced both runoff and soil loss by about 50% compared to the shrub plots. Continued monitoring of the study site will provide data that will be used to analyze complex interactions between independent variables such rainfall amount and intensity, antecedent soil moisture, and soil and vegetation factors, as they influence water balance, and soil erosion. 18 refs., 2 figs., 3 tabs

Temporal dynamics of the compositions and activities of soil microbial communities post-application of the insecticide chlorantraniliprole in paddy soils.

Science.gov (United States)

Wu, Meng; Liu, Jia; Li, Weitao; Liu, Ming; Jiang, Chunyu; Li, Zhongpei

2017-10-01

Chlorantraniliprole (CAP) is a newly developed insecticide widely used in rice fields in China. There has been few studies evaluating the toxicological effects of CAP on soil-associated microbes. An 85-day microcosm experiment was performed to reveal the dissipation dynamics of CAP in three types of paddy soils in subtropical China. The effects of CAP on microbial activities (microbial biomass carbon-MBC, basal soil respiration-BSR, microbial metabolic quotient-qCO 2 , acid phosphatase and sucrose invertase activities) in the soils were periodically evaluated. Microbial phospholipid fatty acid (PLFA) analysis was used to evaluate the change of soil microbial community composition on day 14 and 50 of the experiment. CAP residues were extracted using the quick, easy, cheap, effective, rugged, and safe (QuChERS) method and quantification was measured by high performance liquid chromatography (HPLC). The half-lives (DT 50 ) of CAP were in the range of 41.0-53.0 days in the three soils. The results showed that CAP did not impart negative effects on MBC during the incubation. CAP inhibited BSR, qCO 2 , acid phosphatase and sucrose invertase activities in the first 14 days of incubation in all the soils. After day 14, the soil microbial parameters of CAP-treated soils became statistically at par with their controls. Principal component analysis (PCA) determining abundance of biomarker PLFAs indicated that the application of CAP significantly changed the compositions of microbial communities in all three paddy soils on day 14 but the compositions of soil microbial communities recovered by day 50. This study indicates that CAP does not ultimately impair microbial activities and microbial compositions of these three paddy soil types. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantifying vertical stress transmission and compaction-induced soil structure using sensor mat and X-ray computed tomography

DEFF Research Database (Denmark)

Naveed, Muhammad; Schjønning, Per; Keller, Thomas

2016-01-01

tillage. In this study, partially confined uniaxial compression tests were carried out on intact topsoil columns placed on subsoil columns. Two methods were employed for estimation of stress transmission in soil: (i) soil deformation patterns were quantified using X-ray CT and converted to stress......Accurate estimation of stress transmission in soil and quantification of compaction-induced soil pore structure is important for efficient soil use and management. Continuum mechanics have so far mostly been applied for agricultural soils, even if topsoil structure is aggregated due to regular...... distributions, and (ii) a tactile sensor mat was employed for measuring stresses at the interface of the topsoil and subsoil columns. The resulting soil pore structure under applied stresses was quantified using X-ray CT and by air-permeability measurements. In topsoil discrete stress transmission patterns were...

Effects of Different Sowing Depths and Soil Compactions on Emergence and Initial Growth of Pepper Varieties (Capsicum annum L.

Directory of Open Access Journals (Sweden)

R Shahriari

2013-10-01

Full Text Available One of the main problems in the mass production of pepper transplant is the stickiness of seed coat to the cotyledony leaves that can lead to no emergence or having poor emergence of pepper seedlings. Therefore, in order to evaluate the effects of different sowing depths and soil compactions on emergence and early seedlings growth of pepper, a greenhouse experiment was conducted in the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2010, using a completely randomized design with factorial arrangement and four replications. The experimental factors included different levels of soil compactions (0 (no compaction, 150.5, 681.340 and 1201.7 Pa, different sowing depths (0 (surface, 1 and 2 cm and different pepper varieties (Olter, California Wonder, EM Bell, Anahiem and Iranian Falei. The results indicated that except the seed coat adherence to cotyledon leaves and the emergence percentage traits, the compaction treatments had a significant effect on (dry matter of seedlings, height, leaf area, number of abnormal seedling and mean emergence time were significant. In addition, sowing depth treatments had positive and significant effects on increasing the number of seedling with releasing seed coats from the cotyledony leaves.

Swelling/shrinkage of compacted and natural clayey soils

International Nuclear Information System (INIS)

Nowamooz, H.

2007-12-01

This thesis presents an experimental study performed on compacted loose and natural dense expansive soils using osmotic odometers. Several successive cycles were applied under three different low constant vertical net stresses. The loose soil presents a significant shrinkage accumulation while the dense one produces the swelling accumulation during the suction cycles. The suction cycles induced an equilibrium stage which indicates an elastic behaviour of the samples. At the end of suction cycles, a loading/unloading test was performed at the constant suctions for both materials. The mechanical parameters, i.e. the virgin compression index lambda(s), the apparent pre-consolidation stress p0(s) and the elastic compression index values lambda are completely dependent on the followed stress paths. The whole experimental results made it possible to define the yielding surfaces: suction limit between micro and macrostructure (Lm/M), loading collapse (LC) and saturation curve (SCS). The suction limit (Lm/M) depends completely to the soil fabrics and to the diameter separating the micro- and macrostructure. The pre-consolidation stress variation with suction is represented by the LC surface. The compression curves at different imposed suctions converge towards the saturated state for the high applied vertical stresses. We consider the saturation pressure (Psat) as the necessary pressure to reach the saturated state for an imposed suction. The higher the suction, the higher the saturation pressure. The yielding surface representing this pressure as a function of suction is called the saturation curve (SCS). Generally we can state that the suction cycles unified the LC and SC surfaces and increased the (Lm/M) up to a higher value. (author)

The definition of necessary axial force for extension of initial borehole for soft soil compaction process design

Directory of Open Access Journals (Sweden)

Ter-Martirosyan Zaven

2016-01-01

Full Text Available The article provides an analytical solution of the soil pile and surrounding soil cylinder interaction problem, with the possibility of extension of the pile shaft in its construction. Presents a closed solution for determination of radial and tangential stresses in the process of expansion of the pile shaft, as well as the minimum vertical force sufficient for the crushing of the pile material and move it in radial direction to the specified value. The problem is most actual for compacted soil bases with use of piles-drains of sand and sand-gravel mixture.

Modified swelling pressure apparatus using vapor pressure technique for compacted bentonite

International Nuclear Information System (INIS)

Nishimura, Tomoyoshi

2012-01-01

Document available in extended abstract form only. bentonite. The compacted bentonite is found in unsaturated conditions before applying of swelling due to absorption. The behaviour of compacted bentonite is not consistent with the principle and concepts of classical, saturated soil mechanics. An unsaturated soil theoretical framework using soil water characteristic curve has been fairly established over the past several decades. The soil-water characteristic curve is a relationship between soil moisture and soil suction obtained by the axis translation technique, vapor pressure technique or osmotic suction control which is a key feature in unsaturated soil mechanics. The soil-water characteristic curve can be used for prediction of the shear strength, volume change and hydraulic conductivity. Cui et al. 2002 indicated soil-water characteristic curve of expansive clay soil in high soil suction ranges using osmotic suction technique. Tripathy et al. 2010 described the soil-water characteristic curve both using the axis translation technique and vapor pressure technique in the entire soil suction ranges. Nishimura and Koseki 2011 measured suction of bentonite applied high soil suction due vapor pressure using a chilled mirror dew point potentiometer (WP4-T of DECAGON Device). The bentonite with gravimetric water content of 18 % indicated soil suction of 2.8 MPa at least. It is predicted that suction efforts to swelling pressure and shear strength of unsaturated compacted bentonite. This study focuses on the influence of suction on both swelling pressure and shear strength of compacted bentonite. The soil-water characteristic curve (SWCC) tests were conducted for compacted bentonite using both axis-translation technique and vapor pressure technique. The SWCC had a range from 0 kPa to 296 MPa in suction. The compacted bentonite having two different soil suctions were prepared for swelling pressure tests. Newly swelling pressure testing apparatus was developed in order

Mixed Waste Management Facility (MWMF) closure, Savannah River Plant: Clay cap test section construction report

Energy Technology Data Exchange (ETDEWEB)

1988-02-26

This report contains appendices 3 through 6 for the Clay Cap Test Section Construction Report for the Mixed Waste Management Facility (MWMF) closure at the Savannah River Plant. The Clay Cap Test Program was conducted to evaluate the source, lab. permeability, in-situ permeability, and compaction characteristics, representative of kaolin clays from the Aiken, South Carolina vicinity. (KJD)

Standard and alternative landfill capping design in Germany

International Nuclear Information System (INIS)

Simon, Franz-Georg; Mueller, Werner W.

2004-01-01

Engineered capping systems are in most cases an indispensable and often the only efficient component required by the long-term safety concept for landfills, mine tailings tips and contaminated land. In Germany the composite liner is the main component of standard landfill cappings for municipal and hazardous waste landfills and the compacted clay liner (CCL) for landfills for inert or low-contamination waste. The composite liner is a technically highly effective but very expensive system. Research and experience has given rise to concern about the proper long-term performance of a conventional single CCL as a landfill capping. Therefore, alternative capping systems are discussed and applied for landfills and for the containment of contaminated sites. This paper gives an overview on various alternative engineered cappings and suitable systems for capping reflecting the state of the art and the expert view in Germany. According to the European Council Directive on the landfill of waste an impermeable mineral layer is recommended for the surface sealing of non-hazardous landfills and a composition of artificial sealing liner and impermeable mineral layer for hazardous landfills. In both cases a drainage layer thickness of at least 0.5 m is suggested. These recommendations should be interpreted flexibly and to some extent modified in the light of the experience and results presented in this paper

Fuels planning: science synthesis and integration; environmental consequences fact sheet 14: Fuels reduction and compaction

Science.gov (United States)

Deborah Page-Dumroese

2005-01-01

Moving equipment and logs over the surface of forest soils causes gouges and ruts in the mineral soil, displaces organic matter, and can cause compaction. Compaction is the component of soil productivity most influenced by forest management, but the degree to which soils may be compacted depends on initial soil bulk density. For example, low bulk density soils (such as...

Nonlinear soil-structure interaction analysis of SIMQUAKE II. Final report

International Nuclear Information System (INIS)

Vaughan, D.K.; Isenberg, J.

1982-04-01

This report describes an analytic method for modeling of soil-structure interaction (SSI) for nuclear power plants in earthquakes and discusses its application to SSI analyses of SIMQUAKE II. The method is general and can be used to simulate a three-dimensional structural geometry, nonlinear site characteristics and arbitrary input ground shaking. The analytic approach uses the soil island concept to reduce SSI models to manageable size and cost. Nonlinear constitutive behavior of the soil is represented by the nonlinear, kinematic cap model. In addition, a debonding-rebonding soil-structure interface model is utilized to represent nonlinear effects which singificantly alter structural response in the SIMQUAKE tests. STEALTH, an explicit finite difference code, is used to perform the dynamic, soil-structure interaction analyses. Several two-dimensional posttest SSI analyses of model containment structures in SIMQUAKE II are performed and results compared with measured data. These analyses qualify the analytic method. They also show the importance of including debonding-rebonding at the soil-structure interface. Sensitivity of structural response to compaction characteristics of backfill material is indicated

Density-dependent hydro-mechanical behaviour of a compacted expansive soil

International Nuclear Information System (INIS)

NOWAMOOZ, Hossein; MASROURI, Farimah

2010-01-01

Document available in extended abstract form only. Clayey soils are widely used in geotechnical engineering for dam cores, barriers in waste landfills and for engineered barriers in nuclear waste storage facilities. In the latter case, the used materials contain a large amount of smectite which is a highly swelling clay. On site, they can be submitted to complex suction/ stress/temperature variations that could change dramatically their hydro-mechanical behavior, meaning their saturated and unsaturated mechanical characteristics. To further our knowledge of the coupling between the hydraulic and mechanical behaviour of the swelling soils, this paper presents an experimental study on a swelling bentonite/silt mixture using osmotic odometers. A loading/unloading cycle was applied to samples with different initial dry densities (1.27, 1.48, and 1.55 Mg.m -3 ) at different constant suctions (0, 2, and 8 MPa). These experimental results provided a sufficient database to analytically model the mechanical behavior of the swelling soil and define three yielding surfaces: - the Suction Limit between Micro- and Macrostructure (s m/M ) and the Suction Limit between Nano- and Microstructure (s n/m ), which depend completely on the soil fabrics and the diameter separating the nano-, micro-, and macrostructure, - the Loading Collapse (LC) curve, representing the pre-consolidation stress variation as a function of suction, - the Saturation Curve (SC), representing the variation of the saturation stress (P sat ) as a function of suction. In general, we can state that the increase of compaction pressure unified the LC and SC surfaces and decreased the (s m/M ) value without modifying the (s n/m ) value. (authors)

Soil compaction and gamma radiation ({sup 60}Co) in the development of the cowpea beans [Vigna unguiculata, (L) Walp]; Compactacao do solo e radiacao gama ({sup 60}Co) no desenvolvimento do feijao caupi [Vigna unguiculata, (L) Walp

Energy Technology Data Exchange (ETDEWEB)

Viana, Eliane Ferreira; Colaco, Waldeciro [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Radioagronomia]. E-mails: aroucha@ufpe.br; wcolaco@ufpe.br

2005-08-15

The objective is to investigate the effect of compaction and increased doses of gamma radiation on the development of cowpea [Vigna unguiculata, (L) Walp] var. IPA-206 cultivated in a Neossolo fluvic soil, artificially compacted. Significant differences were observed in plant height, with the increase doses in soil density (1.30 Mg.m{sup -3} - compacted soil and 1.70 Mg.m{sup -3} - non-compacted soil), and in response to increased doses of irradiation (y-rays) [ [0, 100, 200 and 300 Gy). The diameter of the stem was significantly reduced in response to the increase in soil density, however the same did not occur in relation to the doses of irradiation (y-rays) holding capacity of the soil was reduced in response to the increase in soil density. (author)

The estimation of parameter compaction values for pavement subgrade stabilized with lime

Science.gov (United States)

Lubis, A. S.; Muis, Z. A.; Simbolon, C. A.

2018-02-01

The type of soil material, field control, maintenance and availability of funds are several factors that must be considered in compaction of the pavement subgrade. In determining the compaction parameters in laboratory desperately requires considerable materials, time and funds, and reliable laboratory operators. If the result of soil classification values can be used to estimate the compaction parameters of a subgrade material, so it would save time, energy, materials and cost on the execution of this work. This is also a clarification (cross check) of the work that has been done by technicians in the laboratory. The study aims to estimate the compaction parameter values ie. maximum dry unit weight (γdmax) and optimum water content (Wopt) of the soil subgrade that stabilized with lime. The tests that conducted in the laboratory of soil mechanics were to determine the index properties (Fines and Liquid Limit/LL) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) > 10% were made with additional 3% lime for 30 samples. By using the Goswami equation, the compaction parameter values can be estimated by equation γd max # = -0,1686 Log G + 1,8434 and Wopt # = 2,9178 log G + 17,086. From the validation calculation, there was a significant positive correlation between the compaction parameter values laboratory and the compaction parameter values estimated, with a 95% confidence interval as a strong relationship.

Visual soil evaluation

DEFF Research Database (Denmark)

Visual Soil Evaluation (VSE) provides land users and environmental authorities with the tools to assess soil quality for crop performance. This book describes the assessment of the various structural conditions of soil, especially after quality degradation such as compaction, erosion or organic...... and nutrient leaching, and for diagnosing and rectifying erosion and compaction in soils....

Compactação do solo na cultura do feijoeiro. I: efeitos nas propriedades físico-hídricas do solo Soil compaction in a bean crop. I: effects on soil physical and water properties

Directory of Open Access Journals (Sweden)

Luís F. Stone

2002-01-01

Full Text Available O problema de compactação do solo vem aparecendo sistematicamente na região do Cerrado, onde os sistemas convencionais de manejo do solo têm causado desagregação excessiva da camada arável, o encrostamento superficial e a formação de camadas coesas ou compactadas (pé-de-grade ou pé-de-arado. Como alternativa, os agricultores adotaram o Sistema Plantio Direto; entretanto, em várias situações vêm sendo relatadas ocorrências de aumento da densidade do solo e diminuição da macroporosidade, o que tem sido diagnosticado como compactação, fazendo com que o agricultor seja obrigado a movimentar o solo. Este trabalho teve por objetivo verificar como a compactação do solo afeta as suas propriedades físicas e de transmissão de água. Para isto, utilizaram-se colunas de solo compactadas artificialmente, para produzir densidades do solo de 1,0; 1,2; 1,4 e 1,6 kg dm-3. As propriedades de transmissão de água foram determinadas com infiltrômetros de tensão, para as cargas de pressão de -0,5; -2,0 e -6,0 cm de água. O aumento da densidade do solo aumentou sua resistência à penetração e reduziu linearmente a porosidade total e a macroporosidade. Houve ainda, redução no tamanho dos poros para o fluxo de água, reduzindo a condutividade hidráulica do solo. Esta redução foi mais acentuada na maior carga de pressão testada. Com a carga de pressão de -2,0 cm de água, a redução no tamanho dos poros foi parcialmente compensada com aumento do seu número. O método do infiltrômetro de tensão mostrou-se adequado em distinguir diferenças nas propriedades de transmissão de água de um solo submetido a diferentes níveis de compactação.Soil compaction is a problem in the Savanna region, where conventional soil tillage systems have caused excessive disaggregation of the arable layer, superficial crusts, and compacted subsuperficial layers. As an alternative, the farmers have adopted the no-tillage system. However, in various

Excavation and internment of depleted uranium and thorium soils, AHMC Jonesboro, Tennessee

International Nuclear Information System (INIS)

Bernhardt, D.E.; Prewett, S.V.; Boddy, J.R.

1986-01-01

This report describes the construction activities for the rockfilled berm and the excavation and disposal of contaminated soil, and the activities to certify the adequacy of the remedial activities. It focuses on the final closure. Mishu and Prewett in a paper in this proceeding provide additional information of the rockfilled wall. The final phase of the remedial program, referred to as the pond closure project, encompassed excavation of contaminated soil from the pond site and entombment of the waste in an encapsulating clay cell. The disposal cell was located at the pond site, and was situated above the level of the projected 100- and 500-year floods from Little Limestone Creek, which is adjacent to the site. The cell was built by completely enclosing the contaminated soil in a compacted clay liner and covering it with a compacted clay cap, each having a minimum thickness of four feet. Contaminated soil from the pond area and Aerojet Heavy Metals Company (AHMC) completed the remedial program for an inactive evaporation pond at its facility near Jonesboro, Tennessee during the summer of 1985. The pond had been used for process liquid wastes containing depleted uranium and thorium. Depleted uranium is a by-product of uranium richment, does not refer to use in a reactor, and does not contain Ra-226 or the associated decay products

Effects of soil compaction on residual stand growth in central Appalachian hardwood forest: a preliminary case study

Science.gov (United States)

Jingxin Wang; Chris LeDoux; Michael Vanderberg; Li Yaoxiang

2006-01-01

A preliminary study that quantified the impacts of soil compaction on residual tree growth associated with ground-based skidding traffic intensity and turn payload size was investigated in the central Appalachian hardwood forest. The field study was carried out on a 20-acre tract of the West Virginia University Research Forest. Skid trails were laid out in 170' -...

Combining hyperspectral imagery and legacy measured soil profiles to map subsurface soil properties in a Mediterranean area (Cap-Bon, Tunisia)

Science.gov (United States)

Lagacherie, Philippe; Sneep, Anne-Ruth; Gomez, Cécile

2013-04-01

Previous studies have demonstrated that Visible Near InfraRed (Vis-NIR) Hyperspectral imagery is a cost-efficient way for mapping soil properties at fine resolutions (~5m) over large areas. However, such mapping is only feasible for soil surface since the effective penetration depths of optical sensors do not exceed several millimetres. This study aimed to extend the use of Vis-NIR hyperspectral imagery to the mapping of subsurface properties at three intervals of depth (15-30 cm, 30-60 cm and 60-100 cm) as specified by the GlobalSoilMap project. To avoid additional data collection, our basic idea was to develop an original Digital Soil Mapping approach that combines the digital maps of surface soil properties obtained from Vis-NIR hyperspectral imagery with legacy soil profiles of the region and with easily available images of DEM-derived parameters. The study was conducted in a pedologically-contrasted 300km² cultivated area located in the Cap Bon region (Northern Tunisia). AISA-Dual Vis-NIR hyperspectral airborne data were acquired over the studied area with a fine spatial resolution (5 m) and fine spectral resolution (260 spectral bands from 450 to 2500nm). Vegetated surfaces were masked to conserve only bare soil surface which represented around 50% of the study area. Three soil surface properties (clay and sand contents, Cation Exchange Capacity) were successfully mapped over the bare soils, from these data using Partial Least Square Regression models (R2 > 0.7). We used as additional data a set of images of landscape covariates derived from a 30 meter DEM and a local database of 152 legacy soil profiles from which soil properties values at the required intervals of depths were computed using an equal-area-spline algorithm. Our Digital Soil Mapping approach followed two steps: i) the development of surface-subsurface functions - linear models and random forests - that estimates subsurface property values from surface ones and landscape covariates and that

The effect of freeze-thaw cycles on the hydraulic conductivity of compacted clay

International Nuclear Information System (INIS)

Waite, D.; Anderson, L.; Caliendo, J.; McFarland, M.

1994-01-01

A study was conducted to investigate the detrimental effects of freeze-thaw on the hydraulic conductivity of compacted clay. The purpose of this study was to determine the effect that molding water content has on the hydraulic conductivity of a compacted clay soil that is subjected to freeze-thaw cycles, and to determine the relationship between the number of freeze-thaw cycles and the hydraulic conductivity of the compacted clay soil. Clay soils compacted and frozen wet of optimum experienced an increase in hydraulic conductivity of approximately 140 fold. The hydraulic conductivity of clay compacted dry of optimum increased ten fold. These results are consistent with recent research which suggests that clay compacted wet of optimum experiences large increases in hydraulic conductivity while the hydraulic conductivity of clay compacted dry of optimum increases to a lesser extent. 12 refs., 9 figs

Comparative ecotoxicity of chlorantraniliprole to non-target soil invertebrates.

Science.gov (United States)

Lavtižar, Vesna; Berggren, Kristina; Trebše, Polonca; Kraak, Michiel H S; Verweij, Rudo A; van Gestel, Cornelis A M

2016-09-01

The insecticide chlorantraniliprole (CAP) is gaining importance in agricultural practice, but data on its possible negative effects on non-target organisms is severely deficient. This study therefore determined CAP toxicity to non-target soil invertebrates playing a crucial role in ecosystem functioning, including springtails (Folsomia candida), isopods (Porcellio scaber), enchytraeids (Enchytraeus crypticus) and oribatid mites (Oppia nitens). In sublethal toxicity tests in Lufa 2.2 soil, chronic exposure to CAP concentrations up to 1000 mg/kgdw did not affect the survival and reproduction of E. crypticus and O. nitens nor the survival, body weight and consumption of P. scaber. In contrast, the survival and reproduction of F. candida was severely affected, with an EC50 for effects on reproduction of 0.14 mg CAP/kgdw. The toxicity of CAP to the reproduction of F. candida was tested in four different soils following OECD guideline 232, and additionally in an avoidance test according to ISO guideline 17512-2. A significantly lower toxicity in soils rich in organic matter was observed, compared to low organic soils. Observations in the avoidance test with F. candida suggest that CAP acted in a prompt way, by affecting collembolan locomotor abilities thus preventing them from escaping contaminated soil. This study shows that CAP may especially pose a risk to non-target soil arthropods closely related to insects, while other soil invertebrates seem rather insensitive. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rate type isotach compaction of consolidated sandstone

NARCIS (Netherlands)

Waal, J.A. de; Thienen-Visser, K. van; Pruiksma, J.P.

2015-01-01

Laboratory experiments on samples from a consolidated sandstone reservoir are presented that demonstrate rate type compaction behaviour similar to that observed on unconsolidated sands and soils. Such rate type behaviour can have large consequences for reservoir compaction, surface subsidence and

Test work of sand compaction pile method on coal ash soil foundation. Sekitanbai jiban ni okeru sand compaction pile koho no shiken seko

Energy Technology Data Exchange (ETDEWEB)

Goto, K.; Maeda, S.; Shibata, T. (The Kansai Electric Power Co. Inc., Osaka (Japan))

1992-01-25

As an electric power supply source after the 1990 {prime}s, Nos. 5 and 6 units are additionally being constructed by Kansai Electric Power in its Himeji Power Station No.1 which is an exclusively LNG burning power station. The additional construction site of those units is of soil foundation reclaimed with coal ash which was used residual product in the existing No.1 through No.4 units. As a result of soil foundation survey, the coal ash layer and sand layer were known to be of material to be possibly liquidized at the time of earthquake. As measures against the liquidization, application was basically made of a sand compaction pile (SCP) method which is economical and abundant in record. However, that method was so short of record in the coal ash layer that its evaluation was difficult in soil reforming effect. Therefore, its applicability was evaluated by a work test on the site, which resulted in a confirmation that the coal ash as well as the sand can be sufficiently reformed by the SCP method. Started in September, 1991, the additional construction of Nos. 5 and 6 units in Himeji Power Station No.1 uses a 1.5m pitch SCP method to reform the soil foundation. 3 refs., 10 figs., 1 tab.

Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials

International Nuclear Information System (INIS)

Rachor, Ingke; Gebert, Julia; Groengroeft, Alexander; Pfeiffer, Eva-Maria

2011-01-01

The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm -3 , reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH 4 m -2 d -1 , covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH 4 m -2 d -1 and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of

Analysis of Dynamic Stiffness of Bridge Cap-Pile System

Directory of Open Access Journals (Sweden)

Jinhui Chu

2018-01-01

Full Text Available In order to investigate the applicability of dynamic stiffness for bridge cap-pile system, a laboratory test was performed. A numerical model was also built for this type of system. The impact load was applied on the cap top and the dynamic stiffness was analysed. Then, the effect of the effective friction area between pile and soil was also considered. Finally, the dynamic stiffness relationship between the single pile and the cap-pile system was also compared. The results show that the dynamic stiffness is a sensitive index and can well reflect the static characteristics of the pile at the elastic stage. There is a significant positive correlation between the vertical dynamic stiffness index and bearing capacity of the cap-pile system in the similar formation environment. For the cap-pile system with four piles, the dynamic stiffness is about four times as large as the single pile between 10 and 20 Hz.

Capping hazardous red mud using acidic soil with an embedded layer of zeolite for plant growth.

Science.gov (United States)

Ma, Yingqun; Si, Chunhua; Lin, Chuxia

2014-01-01

A nearly three-year microcosm experiment was conducted to test the effectiveness of capping red mud using acidic soil with an embedded layer of zeolite in sustaining the growth of a grass species. This 'sandwich-structured' design allowed self-sustaining growth of the plants under rain-fed conditions no matter whether the underlying red mud was neutralized or not. During the initial stage, the plants grew better when the red mud was not neutralized with MgCl2 probably due to pH rise in the root zone. Neutralization of red mud led to salinization and pH decrease in the root zone. However, the difference in plant growth performance between these scenarios became less remarkable over time due to gradual improvement of soil conditions in the neutralized scenarios. Continuous leaching of soluble salts and alkali by rainwater extended the root zone to the red mud layer. As a result of vegetative production, soil organic matter rapidly accumulated. This, combined with increase in pH and decrease in salinity, markedly facilitated microbial activities and consequently improved the supply of nutrients. This study provides abasis for field-scale experimental design that will have implications for effectively establishing vegetative cover in red mud disposal sites to control dust hazards.

Soil compaction related to grazing and its effects on herbaceous roots frequency and soil organic matter content in rangelands of SW Spain

Science.gov (United States)

Pulido, Manuel; Schnabel, Susanne; Francisco Lavado Contador, Joaquín; Miralles Mellado, Isabel

2016-04-01

Rangelands in SW Spain occupy a total surface area of approximately 6 million ha and constitute the most representative extensive ranching system of the Iberian Peninsula gathering more than 13 million livestock heads. They are characterised by an herbaceous layer, mostly composed of therophytic species, with a disperse tree cover, mainly holm oak and cork oak (Quercus ilex rotundifolia and Q. suber), interspersed with shrubs in many places. This type of land system is of ancient origin and experienced frequent changes in land use in the past, since agricultural, livestock and forestry activities have coexisted within the same farms. In recent decades, livestock farming has become dominant due, in part, to the subsidies of the Common Agriculture Policy. Since Spain joined the European Union in 1986 until the year 2000, the number of domestic animals doubled, particularly cattle, and consequently animal stocking rates have increased on average from 0.40 AU ha-1 up to 0.70 AU ha-1. This increase in animal stocking rates, along with a progressive substitution of cattle instead of sheep in many farms, has led to the occurrence of land degradation processes such as the reduction of grass cover or soil compaction in heavily grazed areas. Previous research has evidenced higher values of soil bulk density and resistance to penetration as well as larger bare surface areas in spring in fenced areas with animal stocking rates above 1 AU ha-1. However, a better understanding of how increasing bulk density or resistance to penetration influence the frequency of herbaceous roots and how a reduction in the frequency of roots affects soil organic matter content in rangelands is still unknown. Therefore, the main goal of this study was to determine possible relationships between the frequencies of herbaceous roots and soil organic matter content in order to understand the effect of excessive animal numbers on the depletion of soil fertility by reducing progressively the quantity of

Microbial alterations of the soil influenced by induced compaction Alterações microbianas do solo influenciadas por compactação induzida

Directory of Open Access Journals (Sweden)

Breno Pupin

2009-10-01

Full Text Available Compaction is one of the most destructive factors of soil quality, however the effects on the microbial community and enzyme activity have not been investigated in detail so far. The objective of this study was to evaluate the effects of soil compaction caused by the traffic of agricultural machines on the soil microbial community and its enzyme activity. Six compaction levels were induced by tractors with different weights driving over a Eutrustox soil and the final density was measured. Soil samples were collected after corn from the layers 0-0.10 and 0.10-0.20 m. The compaction effect on all studied properties was evident. Total bacteria counts were reduced significantly (by 22-30 % and by 38-41 % of nitrifying bacteria in the soil with highest bulk density compared to the control. On the other hand, fungi populations increased 55-86 % and denitrifying bacteria 49-53 %. Dehydrogenase activity decreased 20-34 %, urease 44-46 % and phosphatase 26-28 %. The organic matter content and soil pH decreased more in the 0-0.10 than in the 0.10-0.20 m layer and possibly influenced the reduction of the microbial counts, except denitrifying bacteria, and all enzyme activities, except urease. Results indicated that soil compaction influences the community of aerobic microorganisms and their activity. This effect can alter nutrient cycling and reduce crop yields.A compactação é um dos fatores mais agravantes para a qualidade do solo, porém o seu efeito na comunidade e atividade enzimática microbiana não tem sido suficientemente estudado. Seis níveis de compactação foram obtidos pela passagem de tratores com diferentes pesos em um Latossolo Vermelho, e a densidade final foi medida. Amostras de solo foram coletadas nas profundidades de 0-10 e 10-20 cm, após a colheita do milho. O efeito da compactação foi evidente em todos os parâmetros estudados, mas nem sempre foi significativo. A contagem das bactérias totais reduziu significativamente em 22

Broadband electromagnetic analysis of compacted kaolin

International Nuclear Information System (INIS)

Bore, Thierry; Scheuermann, Alexander; Wagner, Norman; Cai, Caifang

2017-01-01

The mechanical compaction of soil influences not only the mechanical strength and compressibility but also the hydraulic behavior in terms of hydraulic conductivity and soil suction. At the same time, electric and dielectric parameters are increasingly used to characterize soil and to relate them with mechanic and hydraulic parameters. In the presented study electromagnetic soil properties and suction were measured under defined conditions of standardized compaction tests. The impact of external mechanical stress conditions of nearly pure kaolinite was analyzed on soil suction and broadband electromagnetic soil properties. An experimental procedure was developed and validated to simultaneously determine mechanical, hydraulic and broadband (1 MHz–3 GHz) electromagnetic properties of the porous material. The frequency dependent electromagnetic properties were modeled with a classical mixture equation (advanced Lichtenecker and Rother model, ALRM) and a hydraulic-mechanical-electromagnetic coupling approach was introduced considering water saturation, soil structure (bulk density, porosity), soil suction (pore size distribution, water sorption) as well as electrical conductivity of the aqueous pore solution. Moreover, the relaxation behavior was analyzed with a generalized fractional relaxation model concerning a high-frequency water process and two interface processes extended with an apparent direct current conductivity contribution. The different modeling approaches provide a satisfactory agreement with experimental data for the real part. These results show the potential of broadband electromagnetic approaches for quantitative estimation of the hydraulic state of the soil during densification. (paper)

Biochar impact on water infiltration and water quality through a compacted subsoil layer

Science.gov (United States)

Soils in the SE USA Coastal Plain region frequently have a compacted subsoil layer (E horizon), which is a barrier for water infiltration. Four different biochars were evaluated to increase water infiltration through a compacted horizon from a Norfolk soil (fine-loamy, kaolinitic...

[Impact of biochar amendment on the sorption and dissipation of chlorantraniliprole in soils].

Science.gov (United States)

Wang, Ting-Ting; Yu, Xiang-Yang; Shen, Yaen; Zhang, Chao-Lan; Liu, Xian-Jin

2012-04-01

The effects of biochar amendment on sorption and dissipation of chlorantraniliprole (CAP) in 5 different agricultural soils were studied. Red gum wood (Eucalyptus spp.) derived biochar was amended into a black soil, a yellow soil, a red soil, a purplish soil, and a fluvo-aquic soil at the rate of 0.5% (by weight). The sorption and dissipation behaviors of CAP in soils with and without biochar amendment were measured by batch equilibration technique and dissipation kinetic experiment, respectively. The objective was to investigate the impact of biochar application on the environmental fate of pesticides in agricultural soils with different physical-chemical properties, and evaluate the potential ecological impacts of field application of biochar materials. The results showed that biochar application in soils could enhance the sorption of CAP, but the magnitudes were varied among soils with different properties. Amendment of 0.5% (by weight) biochar in the black soil, which have high content of organic matter (4.59%), resulted in an increase of sorption coefficient (K(d)) by 2.17%; while for the fluvo-aquic soil with organic matter content of 1.16%, amendment of biochar at the same level led to an increase of 139.13%. The sorption capacity of biochar was partially suppressed when biochar was mixed with soils. The calculated K(Fbiochar) of biochar after mixed in the black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were decreased by 96.94%, 90.6%, 91.31%, 68.26%, and 34.59%, respectively, compared to that of the original biochar. The half-lives of CAP in black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were 115.52, 133.30, 154.03, 144.41 and 169.06 d, respectively. In soils amended with biochar, the corresponding half-lives of CAP were extended by 20.39, 35.76, 38.51, 79.19, and 119.75 d, respectively. Similar to the effects of biochar on CAP sorption, in soil with higher content of organic matter, the retardation of CAP

População de Metarhizium anisopliae em diferentes tipos e graus de compactação do solo Metarhizium anisopliae population in differents soil types and compactness degrees

Directory of Open Access Journals (Sweden)

Lourenço Maurício Lanza

2004-12-01

Full Text Available Este trabalho objetivou investigar a influência do tipo e compactação do solo na sobrevivência do fungo Metarhizium anisopliae. A sobrevivência do fungo foi determinada em quatro tipos de solos: Latossolo Vermelho textura argilosa, Latossolo Vermelho textura média, Argissolo Vermelho Amarelo textura arenosa média e Argissolo Vermelho Amarelo textura areno-argilosa, com maior teor de matéria orgânica. Para determinar o efeito da compactação na sobrevivência do fungo usaram-se os três primeiros tipos de solos nas densidades de 1,12, 1,32, 1,50g cm-3; 1,22, 1,44, 1,65g cm-3; 1,30, 1,50, 1,70g cm-3, respectivamente. Por meio da contagem de unidades formadoras de colônias (UFC em placas de Petri, fizeram-se avaliações da sobrevivência do fungo, após zero, 20, 40, 60, 80, 100 e 120 dias de incubação a 27 ± 1ºC. Houve influência significativa do tipo de solo e do grau de compactação na sobrevivência do fungo, obtendo-se maior quantidade de UFC no solo textura areno-argilosa. Entre os demais solos, a maior sobrevivência ocorreu no solo textura arenosa e a menor no solo textura argilosa. O efeito da compactação foi significativo para o tipo de solo, exceto no solo textura arenosa. Independentemente do tipo de solo, a maior sobrevivência foi observada nos valores médios de densidade. A compactação teve maior impacto no solo textura média, onde ocorreu queda mais acentuada na quantidade de UFC em todas as densidades.The aim of this work was to investigate the effect of different soil types and compactness on Metarhizium anisopliae survival. The fungus survivorship was determined in four soil types: Red Latosol with clay texture, Red Latosol with medium texture, Red Yellow Podzolic with medium sand texture and Red Yellow Podzolic with sand-clay texture, with higher amount of organic material. To determine the effect of compactness on fungus survival the first three soil types were used with the following densities

Test Area for Remedial Actions (TARA) site characterization and dynamic compaction of low-level radioactive waste trenches. FY 1988 progress report

Energy Technology Data Exchange (ETDEWEB)

Davis, E. C.; Spalding, B. P.; Lee, S. Y.; Hyder, L. K.

1989-01-01

As part of a low-level radioactive waste burial ground stabilization and closure technology demonstration project, a group of five burial trenches in Oak Ridge National Laboratory (ORNL) Solid Waste Storage Area (SWSA) 6 was selected as a demonstration site for testing trench compaction, trench grouting, and trench cap installation and performance. This report focuses on site characterization, trench compaction, and grout-trench leachate compatibility. Trench grouting and cap design and construction will be the subject of future reports. The five trenches, known as the Test Area for Remedial Actions (TARA) site, are contained within a hydrologically isolated area of SWSA 6; for that reason, any effects of stabilization activities on site performance and groundwater quality will be separable from the influence of other waste disposal units in SWSA 6. To obviate the chronic problem of burial trench subsidence and to provide support for an infiltration barrier cap, these five trenches were dynamically compacted by repeated dropping of a 4-ton weight onto each trench from heights of approximately 7 m.

Numerical evaluation of monofil and subtle-layered evapotranspiration (ET) landfill caps

International Nuclear Information System (INIS)

Wilson, G.V.; Henley, M.; Valceschini, R.

1998-01-01

The US Department of Energy/Nevada Operations Office (DOE/NV) has identified the need to design a low-level waste (LLW) closure cap for the arid conditions at the Nevada Test Site (NTS). As a result of concerns for subsidence impacting the cover, DOE/NV redesigned the LLW cover from one containing a 'hard' infiltration barrier that would likely fail, to a 'soft' (ET) cover that is sufficiently deep to accommodate the hydrologic problems of subsidence. An ET cover is one that does not contain hydrologic barrier layers but relies on soil-water retention and sufficient thickness to store water until evapotranspiration (ET) can remove the moisture. Subtle layering within an ET cap using the native soil could be environmentally beneficial and cost effective

Rill erosion on an oxisol influenced by a thin compacted layer

Directory of Open Access Journals (Sweden)

Edivaldo Lopes Thomaz

2013-10-01

Full Text Available The presence of compacted layers in soils can induce subprocesses (e.g., discontinuity of water flow and induces soil erosion and rill development. This study assesses how rill erosion in Oxisols is affected by a plow pan. The study shows that changes in hydraulic properties occur when the topsoil is eroded because the compacted layer lies close below the surface. The hydraulic properties that induce sediment transport and rill formation (i.e., hydraulic thresholds at which these processes occur are not the same. Because of the resistance of the compacted layer, the hydraulic conditions leading to rill incision on the soil surface differed from the conditions inducing rill deepening. The Reynolds number was the best hydraulic predictor for both processes. The formed rills were shallow and could easily be removed by tillage between crops. However, during rill development, large amounts of soil and contaminants could also be transferred.

Electric Resistance Tests on Compacted Clay Material under Dynamic Load Coupled with Dry-Wet Cycling

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Zheng Lu

2018-01-01

Full Text Available The study of compacted clay material under dynamic load coupled with dry-wet cycling is one of the most important areas in the field of transportation. In this paper, experiments in terms of compacted clay under dynamic load coupled with dry-wet cycling are performed, and synchronous resistivity tests are also conducted. According to the test results, the influences of cumulative plastic strain, dry-wet cycles, and amplitudes on the soil resistivity are analyzed. Then a new damage factor based on resistivity is proposed to evaluate the long-term performance of compacted clay material. The result of research shows that the evolution of the soil resistivity can be divided into two stages, which has a contrary tendency with that of cumulative plastic strain. The dry-wet cycles and amplitudes have a significant effect on the damage of the compacted soil, which indicates that the dry-wet cycling of compacted soil materials should not be ignored in road engineering, especially in rainy and humid areas.

Quick test for infiltration of arable soils

OpenAIRE

Liebl, Boris; Spiegel, Ann-Kathrin

2018-01-01

The quick test makes the consequences of soil compaction on water infiltration and the yield of agricultural crops visible. It promotes an understanding of the effects of soil compaction and the importance of soil-conserving cultivation.

Ground penetrating radar and direct current resistivity evaluation of the desiccation test cap, Savannah River Site

International Nuclear Information System (INIS)

Wyatt, D.E.; Cumbest, R.J.

1996-04-01

The Savannah River Site (SRS) has a variety of waste units that may be temporarily or permanently stabilized by closure using an impermeable cover to prevent groundwater infiltration. The placement of an engineered kaolin clay layer over a waste unit is an accepted and economical technique for providing an impermeable cover but the long term stability and integrity of the clay in non-arid conditions is unknown. A simulated kaolin cap has been constructed at the SRA adjacent to the Burial Ground Complex. The cap is designed to evaluate the effects of desiccation on clay integrity, therefore half of the cap is covered with native soil to prevent drying, while the remainder of the cap is exposed. Measurements of the continuing impermeability of a clay cap are difficult because intrusive techniques may locally compromise the structure. Point measurements made to evaluate clay integrity, such as those from grid sampling or coring and made through a soil cover, may miss cracks, joints or fissures, and may not allow for mapping of the lateral extent of elongate features. Because of these problems, a non-invasive technique is needed to map clay integrity, below a soil or vegetation cover, which is capable of moderate to rapid investigation speeds. Two non-intrusive geophysical techniques, direct current resistivity and ground penetrating radar (GPR), have been successful at the SRS in geologically mapping shallow subsurface clay layers. The applicability of each technique in detecting the clay layer in the desiccation test cap and associated anomalies was investigated

Effect of Postsowing Compaction on Cold and Frost Tolerance of North China Plain Winter Wheat

Directory of Open Access Journals (Sweden)

Caiyun Lu

2017-01-01

Full Text Available Improper postsowing compaction negatively affects soil temperature and thereby cold and frost tolerance, particularly in extreme cold weather. In North China Plain, the temperature falls to 5 degrees below zero, even lower in winter, which is period for winter wheat growing. Thus improving temperature to promote wheat growth is important in this area. A field experiment from 2013 to 2016 was conducted to evaluate effects of postsowing compaction on soil temperature and plant population of wheat at different stages during wintering period. The effect of three postsowing compaction methods—(1 compacting wheel (CW, (2 crosskill roller (CR, and (3 V-shaped compacting roller after crosskill roller (VCRCR—on winter soil temperatures and relation to wheat shoot growth parameters were measured. Results showed that the highest soil midwinter temperature was in the CW treatment. In the 20 cm and 40 cm soil layer, soil temperatures were ranked in the following order of CW > VCRCR > CR. Shoot numbers under CW, CR, and VCRCR treatments were statistically 12.40% and 8.18% higher under CW treatment compared to CR or VCRCR treatments at the end of wintering period. The higher soil temperature under CW treatment resulted in higher shoot number at the end of wintering period, apparently due to reduced shoot death by cold and frost damage.

Cervical Cap

Science.gov (United States)

... Videos for Educators Search English Español The Cervical Cap KidsHealth / For Teens / The Cervical Cap What's in ... Call the Doctor? Print What Is a Cervical Cap? A cervical cap is a small cup made ...

Phytoextraction of Pb and Cu contaminated soil with maize and microencapsulated EDTA.

Science.gov (United States)

Xie, Zhiyi; Wu, Longhua; Chen, Nengchang; Liu, Chengshuai; Zheng, Yuji; Xu, Shengguang; Li, Fangbai; Xu, Yanling

2012-09-01

Chelate-assisted phytoextraction using agricultural crops has been widely investigated as a remediation technique for soils contaminated with low mobility potentially toxic elements. Here, we report the use of a controlled-release microencapsulated EDTA (Cap-EDTA) by emulsion solvent evaporation to phytoremediate soil contaminated with Pb and Cu. Incubation experiments were carried out to assess the effect of Cap- and non-microencapsulated EDTA (Ncap-EDTA) on the mobility of soil metals. Results showed EDTA effectively increased the mobility of Pb and Cu in the soil solution and Cap-EDTA application provided lower and more constant water-soluble concentrations of Pb and Cu in comparison with. Phytotoxicity may be alleviated and plant uptake of Pb and Cu may be increased after the incorporation of Cap-EDTA. In addition phytoextraction efficiencies of maize after Cap- and Ncap-EDTA application were tested in a pot experiment. Maize shoot concentrations of Pb and Cu were lower with Cap-EDTA application than with Ncap-EDTA. However, shoot dry weight was significantly higher with Cap-EDTA application. Consequently, the Pb and Cu phytoextraction potential of maize significantly increased with Cap-EDTA application compared with the control and Ncap-EDTA application.

Peat compaction in deltas : implications for Holocene delta evolution

NARCIS (Netherlands)

van Asselen, S.

2010-01-01

Many deltas contain substantial amounts of peat, which is the most compressible soil type. Therefore, peat compaction potentially leads to high amounts of subsidence in deltas. The main objective of this research was to quantify subsidence due to peat compaction in Holocene fluvial-deltaic settings

Least limiting water range in assessing compaction in a Brazilian Cerrado latosol growing sugarcane

Directory of Open Access Journals (Sweden)

Wainer Gomes Gonçalves

2014-04-01

Full Text Available In the south-central region of Brazil, there is a trend toward reducing the sugarcane inter-harvest period and increasing traffic of heavy harvesting machinery on soil with high water content, which may intensify the compaction process. In this study, we assessed the structural changes of a distroferric Red Latosol (Oxisol by monitoring soil water content as a function of the Least Limiting Water Range (LLWR and quantified its effects on the crop yield and industrial quality of the first ratoon crop of sugarcane cultivars with different maturation cycles. Three cultivars (RB 83-5054, RB 84-5210 and RB 86-7515 were subjected to four levels of soil compaction brought about by a differing number of passes of a farm tractor (T0 = soil not trafficked, T2 = 2 passes, T10 = 10 passes, and T20 = 20 passes of the tractor in the same place in a 3 × 4 factorial arrangement with three replications. The deleterious effects on the soil structure from the farm machinery traffic were limited to the surface layer (0-10 cm of the inter-row area of the ratoon crop. The LLWR dropped to nearly zero after 20 tractor passes between the cane rows. We detected differences among the cultivars studied; cultivar RB 86-7515 stood out for its industrial processing quality, regardless of the level of soil compaction. Monitoring of soil moisture in the crop showed exposure to water stress conditions, although soil compaction did not affect the production variables of the sugarcane cultivars. We thus conclude that the absence of traffic on the plant row maintained suitable soil conditions for plant development and may have offset the harmful effects of soil compaction shown by the high values for bulk density between the rows of the sugarcane cultivars.

Subsoil compaction of a Vertic Cambisol persists three decades after wheel traffic

DEFF Research Database (Denmark)

Lamandé, Mathieu; Schjønning, Per

Compaction of the subsoil can only be alleviated by natural processes. The objective of this study was to evaluate the long-term effect of compaction on the pore system at 0.35 m depth of a heavy clay soil naturally subjected to drying and wetting, and to freezing and thawing, and biological...... activity in Finland. The compaction treatment was inflicted 29 years prior to investigation and included four passes with a tractor-trailer combination with wheel loads up to 4.8 Mg and inflation pressures of 700 kPa. Gas diffusion and air permeability measurements were combined with pycnometer...... characteristics was expected to enhance the ability to deduce how the soil pore system was affected. This included advective air flow measurements at a range of pneumatic pressure drops. Compaction at 0.35 m depth was persistent 29 years after the compaction event. Compaction diminished the diameter of vertical...

Tillage and Farmyard Manure Effects on Crusting and Compacting ...

African Journals Online (AJOL)

Seasonal rainwater losses through increased runoff volumes reduce soil moisture and hence result in agricultural drought. The objective of this study was to examine the hydrological effects of two tillage practices with and without farmyard manure on surface runoff and soil loss of crusting and compacting soils under field ...

Vibro Replacement, Dynamic Compaction, and Vibro Compaction case histories for petroleum storage tank facilities

Energy Technology Data Exchange (ETDEWEB)

Beaton, N; Scott, J. [Geopac West Ltd., Richmond, BC (Canada)

2010-07-01

This paper discussed approaches to tank farm ground improvement via 3 Canadian ground improvement case histories in order to set forth the advantages of ground improvement for foundation support at petroleum storage tank facilities. Each case study featured a particular set of site conditions, performance criteria, and ground improvement techniques selected to attain the desired foundation performance. The first case study involved a Vibro Replacement stone column to meet strict seismicity requirements, the second employed Dynamic Compaction to mitigate deep variable fill within a former gravel pit, and the last encompassed Vibro Compaction applied to a site with a sand fill soil profile. The site conditions, the design requirements, the ground improvement solution, the execution, and the quality control techniques and results were presented for each case history. Soil reinforcement and ground improvement to treat loose and soft soils below heavy storage tanks can be an economical solution to foundation design challenges. However, it is important to select proper methods and tailor the densification programs to the specific subsoil conditions and design requirements. In each application, the selected ground improvement technique exceeded the specified in-situ testing requirements. 3 refs., 9 figs.

Isotopic patterns in caps and stipes in sporocarps reveal patterns of organic nitrogen use by ectomycorrhizal fungi

Science.gov (United States)

Hobbie, Erik; Ouimette, Andrew; Chen, Janet

2016-04-01

Current ecosystem models use inorganic nitrogen as the currency of nitrogen acquisition by plants. However, many trees may gain access to otherwise unavailable soil resources, such as soil organic nitrogen, through their symbioses with ectomycorrhizal fungi, and this pathway of nitrogen acquisition may therefore be important in understanding plant responses to environmental change. Different functional groups of ectomycorrhizal fungi vary in their ability to enzymatically access protein and other soil resources. Such fungal parameters as hyphal hydrophobicity, the presence of rhizomorphs (long-distance transport structures), and exploration strategies (e.g., short-distance versus long-distance, mat formation) correspond with how fungi interact with and explore the environment, and the proportions of different exploration types present will shift along environmental gradients such as nitrogen availability. Isotopic differences between caps and stipes may provide a means to test for organic nitrogen use, since caps and stipes differ in δ13C and δ15N as a result of variable proportions of protein and other classes of compounds, and protein should differ isotopically among de novo synthesis, litter sources, and soil sources. Here, we propose that (1) isotopic differences between caps and stipes could be related to organic nitrogen uptake and to the δ13C and δ15N values of different pools of soil-derived or de novo-synthesized amino acids; (2) these isotopic differences will reflect greater acquisition of soil-derived organic nitrogen by exploration types of greater enzymatic capabilities to degrade recalcitrant nitrogen forms, specifically long-distance, medium-distance fringe, and medium-distance mat exploration types. To test these hypotheses, we use a dataset of isotopic values, %N, and %C in 208 cap/stipe samples collected from Oregon, western USA. δ13C differences in caps and stipes in a multiple regression model had an adjusted r2 of 0.292 (p Ncap-stipe (20

EAF Slag Aggregate in Roller-Compacted Concrete Pavement: Effects of Delay in Compaction

Directory of Open Access Journals (Sweden)

My Ngoc-Tra Lam

2018-04-01

Full Text Available This study investigates the effect of delay in compaction on the optimum moisture content and the mechanical propertie s (i.e., compressive strength, ultrasonic pulse velocity, splitting tensile strength, and modulus of elasticity of roller-compacted concrete pavement (RCCP made of electric arc furnace (EAF slag aggregate. EAF slag with size in the range of 4.75–19 mm was used to replace natural coarse aggregate in RCCP mixtures. A new mixing method was proposed for RCCP using EAF slag aggregate. The optimum moisture content of RCCP mixtures in this study was determined by a soil compaction method. The Proctor test assessed the optimum moisture content of mixtures at various time after mixing completion (i.e., 0, 15, 30, 60, and 90 min. Then, the effect of delay in compaction on the mechanical properties of RCCP mixtures at 28 days of age containing EAF slag aggregate was studied. The results presented that the negative effect on water content in the mixture caused by the higher water absorption characteristic of EAF slag was mitigated by the new mixing method. The optimum water content and maximum dry density of RCCP experience almost no effect from the delay in compaction. The compressive strength and splitting tensile strength of RCCP using EAF slag aggregate fulfilled the strength requirements for pavement with 90 min of delay in compaction.

Evaluation of management alternatives for LWR hulls and caps

International Nuclear Information System (INIS)

Chaudon, L.; Mehling, O.; Cecille, L.; Thiels, G.; Kowa, S.

1993-01-01

Hulls and caps resulting from the reprocessing of LWR spent fuels represent one of the major sources of alpha-bearing solid waste generated during the nuclear fuel cycle. The Commission of the European Communities has undertaken considerable R and D efforts on the development of advanced treatment and conditioning methods for this type of waste. In view of the encouraging results achieved, the Commission launched a theoretical assessment study on cladding waste management. Six practical or potential schemes were identified and elaborated: direct cementation, decontamination prior to cementation, rolling before cementation, rolling followed by embedding in graphite, compaction, and melting in a cold crucible. The economic aspects of each management option were also investigated. This included the assessment of the plant (treatment, conditioning and interim storage), transport and disposal costs. Further consideration will be required to define the best management option for 'cap' wastes. Transport and disposal costs will also require further analysis from an industrial standpoint

Fluxo difusivo de potássio em solos sob diferentes níveis de umidade e de compactação Influence of water content and soil compaction on the potassium diffusion flow into soil

Directory of Open Access Journals (Sweden)

José P. V. da Costa

2009-02-01

Full Text Available O potássio, à semelhança do fósforo, é transportado por difusão até a zona de absorção. Oito níveis de umidade (10, 20, 40, 60, 70, 80, 90 e 100%, definidos em função da porosidade total, foram combinados com dois níveis de densidade do solo (natural e 30% deste valor em três tipos de solo. Como unidade experimental se utilizaram anéis de PVC, que serviram como câmara de difusão, com 5 cm de altura e 10 cm de diâmetro interno. Para avaliação do fluxo difusivo do potássio no solo, lâminas de resina de troca catiônica foram colocadas horizontalmente na superfície das amostras de solo, nas câmaras de difusão. O trabalho foi conduzido em condições de laboratório com temperatura controlada a 25 ± 3 ºC durante 15 dias; após este período, as lâminas foram retiradas e lavadas com jato de água e o potássio adsorvido foi extraído com uma solução de NH4Cl 0,8 mol L-1 + HCl 0,2 mol L-1. O fluxo difusivo de potássio aumentou com os níveis de umidade e diminuiu com a compactação. Com a compactação do solo, observou-se uma relação linear entre os níveis de umidade e a difusão de potássio, mas para os solos não compactados esta relação somente foi observada para o solo mais arenoso; assim, a relação direta entre o fluxo difusivo de potássio e o conteúdo de umidade do solo não é universal, como previsto pela equação de difusão.Potassium, as well as phosphorus, is transported by diffusion to the absortion zone. Eight levels of soil moisture (10, 20, 40, 60, 70, 80, 90 and 100%, defined as a percentage of the soil total porosity, were combined with two soil densities (the natural bulk density and a compaction corresponding to 30% above the natural bulk density in three soil samples, varying in their physiochemical characteristics, and the potassium diffusive flux (KDF was measured using resin strips. To determine KDF, the resin strips were placed on the top of the soil samples. Chambers made of PVC

Responses of soil respiration and barley growth to modified supply of oxygen in the soil

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A. SIMOJOKI

2008-12-01

Full Text Available Roots of dry-land plants are supplied with oxygen mainly by molecular diffusion from soil air. Roots may suffer from hypoxia if soil aeration is reduced by compaction and wetting. Although the mechanisms involved are well known, more research is needed to relate soil aeration status to plant growth. The effects of reduced oxygen supply on soil respiration and the growth of barley seedlings were studied in pot experiments with fine sand soil, where the soil air composition was varied by flushing the soil with gas streams containing 0%, 2%, 6%, 10% or 20% O2 independently of compactness (bulk density 1.4, 1.6 Mg m-3 and wetness (air space 0-5%, >5%. Plant growth decreased only at 0-2% O2 in the loose moist soil but as early as 20% O2 in the wet soil. Soil compaction impaired plant growth regardless of wetting and aeration. In the loose moist soil cropped with barley, the respiration rate (emission of CO2 did not decrease at 6% O2 but decreased clearly at 0-2% O2. The results compared fairly well with the critical oxygen concentrations calculated by a simple multicylindrical model, in which the water-film thickness around the roots was estimated using soil water retention data.

Dynamic compaction with high energy of sandy hydraulic fills

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Khelalfa Houssam

2017-09-01

Full Text Available A case study about the adoption of the dynamic compaction technique with high energy in a sandy hydraulic fill is presented. The feasibility of this technique to ensure the stability of the caisson workshop and to minimize the risk of liquefaction during manufacture. This Article is interested to establish diagnostic of dynamic compaction test, basing on the results of SPT tests and quality control as well as the details of work of compaction and the properties of filling materials. A theory of soil response to a high-energy impact during dynamic compaction is proposed.

Cervical Cap

Science.gov (United States)

... giving birth vaginally, which means the cervical cap may not fit as well. Inconsistent or incorrect use of the cervical cap increases your risk of pregnancy. For example, you may get pregnant when using the cervical cap if: ...

Soybean productivity in Rhodic Hapludox compacted by the action of furrow openers

Directory of Open Access Journals (Sweden)

Robson Gonçalves Trentin

2017-11-01

Full Text Available The heavy traffic of machines in no-tillage systems causes problems as soil compaction and loss of crops productivity. The objective of this paper is to evaluate the productivity of soybeans in reference to furrow openers and the levels of soil compaction in two crops. The experiment was conducted on Rhodic Hapludox by tracing random blocks with subdivided parcels. The soil bulk density levels were laid out in the parcels (1.16, 1.20, 1.22, and 1.26 Mg m-3 and the furrowers in the sub-parcels (double disc and shanks. The resistance to penetration, depth of the furrow, mobilized soil area, final plant stands, height of plants, mean number of beans by pod, 1,000 bean mass, number of pods per plant and productivity of the culture were evaluated. The resistance to penetration increased with the levels of soil compaction regardless of the farming year and up to a depth of 0.20 m. In the first crop, higher productivity with the use of the shank was observed. In the second crop, the use of the shank resulted in an increase in depth of the furrow, mobilized soil, height of the plants and final stand of the plants, but this did not indicate an increase in productivity.

Tillage Effects on Soil Properties & Respiration

Science.gov (United States)

Rusu, Teodor; Bogdan, Ileana; Moraru, Paula; Pop, Adrian; Duda, Bogdan; Cacovean, Horea; Coste, Camelia

2015-04-01

Soil tillage systems can be able to influence soil compaction, water dynamics, soil temperature and soil structural condition. These processes can be expressed as changes of soil microbiological activity, soil respiration and sustainability of agriculture. Objectives of this study were: 1) to assess the effects of tillage systems (Conventional System-CS, Minimum Tillage-MT, No-Tillage-NT) on soil compaction, soil temperature, soil moisture and soil respiration and 2) to establish the relationship that exists in changing soil properties. Three treatments were installed: CS-plough + disc; MT-paraplow + rotary grape; NT-direct sowing. The study was conducted on an Argic-Stagnic Faeoziom. The MT and NT applications reduce or completely eliminate the soil mobilization, due to this, soil is compacted in the first year of application. The degree of compaction is directly related to soil type and its state of degradation. The state of soil compaction diminished over time, tending toward a specific type of soil density. Soil moisture was higher in NT and MT at the time of sowing and in the early stages of vegetation and differences diminished over time. Moisture determinations showed statistically significant differences. The MT and NT applications reduced the thermal amplitude in the first 15 cm of soil depth and increased the soil temperature by 0.5-2.20C. The determinations confirm the effect of soil tillage system on soil respiration; the daily average was lower at NT (315-1914 mmoli m-2s-1) and followed by MT (318-2395 mmoli m-2s-1) and is higher in the CS (321-2480 mmol m-2s-1). Comparing with CS, all the two conservation tillage measures decreased soil respiration, with the best effects of no-tillage. An exceeding amount of CO2 produced in the soil and released into the atmosphere, resulting from aerobic processes of mineralization of organic matter (excessive loosening) is considered to be not only a way of increasing the CO2 in the atmosphere, but also a loss of

In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part II-evaluation of sorption materials

International Nuclear Information System (INIS)

Randall, Paul M.; Yates, Brian J.; Lal, Vivek; Darlington, Ramona; Fimmen, Ryan

2013-01-01

The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate and extent of methylation. This research examined low cost, readily available, capping materials for their ability to sequester Hg and MeHg. Furthermore, selected capping materials were evaluated to inhibit the methylation of Hg in an incubation study as well as the capacity of a selected capping material to inhibit translocation of Hg and MeHg with respect to ebullition-facilitated contaminant transport in a column study. Results indicated that bauxite had a better capacity for mercury sorption than the other test materials. However, bauxite as well as soil capping materials did not decrease methylation to a significant extent. Materials with larger surface areas, higher organic matter and acid volatile sulfide (AVS) content displayed a larger partitioning coefficient. In the incubation experiments, the presence of a carbon source (lactate), electron acceptor (sulfate) and the appropriate strains of SRB provided the necessary conditions for Hg methylation to occur. The column study showed effectiveness in sequestering Hg and MeHg and retarding transport to the overlying water column; however, disturbances to the soil capping material resulting from gas ebullition negated its effectiveness

In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part II-evaluation of sorption materials

Energy Technology Data Exchange (ETDEWEB)

Randall, Paul M., E-mail: randall.paul@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Yates, Brian J.; Lal, Vivek; Darlington, Ramona [Battelle, 505 King Avenue, Columbus, OH 43201 (United States); Fimmen, Ryan [Geosyntec Consultants, 150 E. Wilson Bridge Road, Suite 232, Worthington, OH 43085 (United States)

2013-08-15

The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate and extent of methylation. This research examined low cost, readily available, capping materials for their ability to sequester Hg and MeHg. Furthermore, selected capping materials were evaluated to inhibit the methylation of Hg in an incubation study as well as the capacity of a selected capping material to inhibit translocation of Hg and MeHg with respect to ebullition-facilitated contaminant transport in a column study. Results indicated that bauxite had a better capacity for mercury sorption than the other test materials. However, bauxite as well as soil capping materials did not decrease methylation to a significant extent. Materials with larger surface areas, higher organic matter and acid volatile sulfide (AVS) content displayed a larger partitioning coefficient. In the incubation experiments, the presence of a carbon source (lactate), electron acceptor (sulfate) and the appropriate strains of SRB provided the necessary conditions for Hg methylation to occur. The column study showed effectiveness in sequestering Hg and MeHg and retarding transport to the overlying water column; however, disturbances to the soil capping material resulting from gas ebullition negated its effectiveness.

Subsurface moisture regimes and tracer movement under two types of trench-cap designs for shallow land burial sites

International Nuclear Information System (INIS)

Perkins, B.A.; Cokal, E.J.

1986-03-01

The Los Alamos work has focused on proper design of shallow land burial (SLB) sites in arid and semiarid regions and on applying corrective measures to existing sites. One of the most important design features affecting the probability of movement of radionuclides in SLB sites is the type of trench cap placed over the waste. The cap influences such interdependent parameters as erosion, water infiltration and percolation, and biointrusion. To obtain experimental data for arid and semiarid sites, two different designs of trench caps, one with topsoil underlain with a cobble/gravel biobarrier and one with topsoil underlain with crushed tuff, were compared with respect to (1) seasonal changes in volumetric soil water content, and (2) downward migration of tracers emplaced directly below each type of trench cap. The causes for the large differences in concentrations found in this experiment need to be investigated further. Problems in environmental modeling and monitoring of arid and semiarid SLB sites because of heterogeneities in the soil profiles and their implications for SLB waste management need to be better understood. More work in trench-cap design and its influence on the many pathways available for mobilization is needed

Anti-pp,. cap alpha cap alpha. and p. cap alpha. elastic scattering at high energies and Chou-Yang conjecture

Energy Technology Data Exchange (ETDEWEB)

Saleem, M.; Fazal-e-Aleem; Rifique, M.

1987-03-01

The recent experimental measurements for anti-pp and ..cap alpha cap alpha.. elastic scattering at high energies have shown that the Chou-Yang conjecture regarding the relationship between the electromagnetic and the hadronic form factor of a particle is only an approximation. A new ansatz has been proposed to obtain hadronic form factors of proton and the ..cap alpha..-particle. These form factors have been used to explain the various characteristics of anti-pp, ..cap alpha cap alpha.. and p..cap alpha.. elastic scattering at high energies.

Soil Behavior Under Blast Loading

Science.gov (United States)

2010-12-01

in detail (Lade 2005, Prevost and Popescu 1996, Chen and Baladi 1985). Models that are appropriate to be implemented into finite element programs...Chen and Baladi 1985). As the soil strain hardens, both the cone and the end cap expand. This concept of cap envelope was a major step forward...hardening cap model (Chen and Baladi 1985) 17 The modified Cam-clay model was developed at Cambridge University by Roscoe et al. (1963). This

Soil microbes and soil respiration of Mongolian Steppe soils under grazing stress.

Science.gov (United States)

Bölter, Manfred; Krümmelbein, Julia; Horn, Rainer; Möller, Rolf; Scheltz, Annette

2012-04-01

Soils of Northern China were analysed for their microbiological and soil physical properties with respect to different grazing stress. An important factor for this is soil compaction and related aeration due to pore size shifts. Bulk density increases significantly with increasing grazing intensity and soil carbon contents show decreasing values from top to depth. Organic carbon (LOI) concentrations decrease significantly with increasing grazing intensity. The data on LOI (2-5.8%) approximate 10-30 mg C, our data on glucose show values between 0.4-1.2 mg, i.e. approx. 4% of total carbon. Numbers and biomass of bacteria show generally a decreasing trend of those data at grazed and ungrazed sites, numbers range between 0.4 and 8.7 x10(8) g(-1) d.wt., bacterial biomass between 0.4 and 3.8 microg Cg(-1). This need to be recorded in relation to soil compaction and herewith-hampered aeration and nutrient flow. The temperature-respiration data also allow getting an idea of the Q10-values for soil respiration. The data are between 2.24 (5-15 degrees C) and 1.2 (25-35 degrees C). Our data are presented with a general review of biological properties of Mongolian Steppe soils.

Effects of biochar on hydraulic conductivity of compacted kaolin clay.

Science.gov (United States)

Wong, James Tsz Fung; Chen, Zhongkui; Wong, Annie Yan Yan; Ng, Charles Wang Wai; Wong, Ming Hung

2018-03-01

Compacted clay is widely used as capillary barriers in landfill final cover system. Recently, biochar amended clay (BAC) has been proposed as a sustainable alternative cover material. However, the effects of biochar on saturated hydraulic conductivity (k sat ) of clay with high degree of compaction is not yet understood. The present study aims to investigate the effects of biochar on k sat of compacted kaolin clay. Soil specimens were prepared by amending kaolin clay with biochar derived from peanut-shell at 0, 5 and 20% (w/w). The k sat of soil specimens was measured using a flexible water permeameter. The effects of biochar on the microstructure of the compacted clay was also investigated using MIP. Adding 5% and 20% of biochar increased the k sat of compacted kaolin clay from 1.2 × 10 -9 to 2.1 × 10 -9 and 1.3 × 10 -8 ms -1 , respectively. The increase in k sat of clay was due to the shift in pore size distribution of compacted biochar-amended clay (BAC). MIP results revealed that adding 20% of biochar shifted the dominant pore diameter of clay from 0.01-0.1 μm (meso- and macropores) to 0.1-4 μm (macropores). Results reported in this communication revealed that biochar application increased the k sat of compacted clay, and the increment was positively correlated to the biochar percentage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil Stabilization with Lime for the Construction of Forest Roads

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Reginaldo Sérgio Pereira

2018-02-01

Full Text Available ABSTRACT The mechanical performance of soil stabilization using lime to improve forest roads was assessed. This study was conducted with lateritic soil (LVAd30 using lime content of 2% in the municipality of Niquelândia, Goiás state, Brazil. Geotechnical tests of soil characterization, compaction, and mechanical strength were performed applying different compaction efforts and curing periods. The results showed that lime content significantly changed the mechanical performance of natural soil, increasing its mechanical strength and load-carrying capacity. Compaction effort and curing time provided different responses in the unconfined compressive strength (UCS and California Bearing Ratio (CBR tests. The best UCS value (786.59 kPa for the soil-lime mixture was achieved with modified compaction effort and curing time of 28 days. In the CBR test, soil-lime mixtures compacted at intermediate and modified efforts and cured for 28 days were considered for application as subbase material of flexible road pavements, being a promising alternative for use in layers of forest roads.

Cradle Cap (For Parents)

Science.gov (United States)

... Safe Videos for Educators Search English Español Cradle Cap (Infantile Seborrheic Dermatitis) KidsHealth / For Parents / Cradle Cap ( ... many babies develop called cradle cap. About Cradle Cap Cradle cap is the common term for seborrheic ...

Geotechnical properties of Egyptian collapsible soils

Directory of Open Access Journals (Sweden)

Khaled E. Gaaver

2012-09-01

Full Text Available The risk of constructing structures on collapsible soils presents significant challenges to geotechnical engineers due to sudden reduction in volume upon wetting. Identifying collapsible soils when encountered in the field and taking the needed precautions should substantially reduce the risk of such problems usually reported in buildings and highways. Collapsible soils are those unsaturated soils that can withstand relatively high pressure without showing significant change in volume, however upon wetting; they are susceptible to a large and sudden reduction in volume. Collapsible soils cover significant areas around the world. In Egypt, collapsible soils were observed within the northern portion of the western desert including Borg El-Arab region, and around the city of Cairo in Six-of-October plateau, and Tenth-of-Ramadan city. Settlements associated with development on untreated collapsible soils usually lead to expensive repairs. One method for treating collapsible soils is to densify their structure by compaction. The ongoing study presents the effect of compaction on the geotechnical properties of the collapsible soils. Undisturbed block samples were recovered from test pits at four sites in Borg El-Arab district, located at about 20 km west of the city of Alexandria, Egypt. The samples were tested in both unsoaked and soaked conditions. Influence of water inundation on the geotechnical properties of collapsible soils was demonstrated. A comparative study between natural undisturbed and compacted samples of collapsible soils was performed. An attempt was made to relate the collapse potential to the initial moisture content. An empirical correlation between California Bearing Ratio of the compacted collapsible soils and liquid limit was adopted. The presented simple relationships should enable the geotechnical engineers to estimate the complex parameters of collapsible soils using simple laboratory tests with a reasonable accuracy.

Experiment Analysis and Modelling of Compaction Behaviour of Ag60Cu30Sn10 Mixed Metal Powders

Science.gov (United States)

Zhou, Mengcheng; Huang, Shangyu; Liu, Wei; Lei, Yu; Yan, Shiwei

2018-03-01

A novel process method combines powder compaction and sintering was employed to fabricate thin sheets of cadmium-free silver based filler metals, the compaction densification behaviour of Ag60Cu30Sn10 mixed metal powders was investigated experimentally. Based on the equivalent density method, the density-dependent Drucker-Prager Cap (DPC) model was introduced to model the powder compaction behaviour. Various experiment procedures were completed to determine the model parameters. The friction coefficients in lubricated and unlubricated die were experimentally determined. The determined material parameters were validated by experiments and numerical simulation of powder compaction process using a user subroutine (USDFLD) in ABAQUS/Standard. The good agreement between the simulated and experimental results indicates that the determined model parameters are able to describe the compaction behaviour of the multicomponent mixed metal powders, which can be further used for process optimization simulations.

GS Soil - Assessment and strategic development of INSPIRE compliant Geodata-Services for European Soil Data

DEFF Research Database (Denmark)

Krogh, Paul Henning; Münier, Bernd

facilities and long term observations as part of the Annex III theme "Environmental Monitoring Facilities", • Information about the soil related aspects of Annex III theme "Natural Risk Zones" as e.g. landslides, soil erosion, soil compaction, soil organic carbon decline, salinization, acidification and soil...

Priority areas in the Soil Framework Directive : the significance of soil biodiversity and ecosystem services

NARCIS (Netherlands)

Rutgers, M.; Jagers op Akkerhuis, G.A.J.M.; Bloem, J.

2010-01-01

Seven soil threats are distinguished in the draft text of the Soil Framework Directive of the European Commission. Soil organic matter decline and soil compaction are the most relevant for the Netherlands due to intensive agricultural land management. Loss of soil biodiversity should be considered

IR SPECTRAL MAPPING OF THE MARTIAN SOUTH POLAR RESIDUAL CAP USING CRISM

Directory of Open Access Journals (Sweden)

J. Campbell

2016-06-01

Full Text Available Polycyclic aromatic hydrocarbons (PAHs are considered to be important in theories of abiogenesis (Allamandola, 2011 . There is evidence that PAHs have been detected on two icy Saturnian satellites using the Visual and Infrared Mapping Spectrometer (VIMS on the Cassini spacecraft (Cruikshank et al., 2007. The hypothesised presence of PAHs in Mars south polar cap has not been systematically examined even though the Mars south polar cap may allow the preservation of organic molecules that are typically destroyed at the Martian surface by UV radiation (Dartnell et al. 2012. This hypothesis is supported by recent analyses of South Polar Residual Cap (SPRC structural evolution (Thomas et al., 2009 that suggest the possibility that seasonal and long term sublimation may excavate dust particles from within the polar ice. Periodic sublimation is believed to be responsible for the formation of so-called “Swiss Cheese Terrain”, a unique surface feature found only in the Martian south polar residual cap consisting of flat floored, circular depressions (Byrne, 2009. We show the first examples of work towards the detection of PAHs in Swiss Cheese Terrain, using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM, on board NASA’s Mars Reconnaissance Orbiter (MRO. CRISM is designed to search for mineralogical indications of past and present water, thus providing extensive coverage of the south polar cap. In this work, we discuss whether CRISM infrared spectra can be used to detect PAHs in Swiss Cheese Terrain and demonstrate a number of maps showing shifts in spectral profiles over the SPRC.

effect of compactive effort on strength indices of laterite treated

African Journals Online (AJOL)

PROF. BARTH EKWEME

Atterberg's limits test, compaction test, California bearing ratio (CBR) and unconfined ... size, highclay content, and the degree to which the soils have been ... in the stabilization of Ikpayongo laterite with cement. However lime which seems to be the conventional ... as soil modification or stabilization, depending on treatment ...

How serious a problem is subsoil compaction in the Netherlands? A survey based on probability sampling

Science.gov (United States)

Brus, Dick J.; van den Akker, Jan J. H.

2018-02-01

Although soil compaction is widely recognized as a soil threat to soil resources, reliable estimates of the acreage of overcompacted soil and of the level of soil compaction parameters are not available. In the Netherlands data on subsoil compaction were collected at 128 locations selected by stratified random sampling. A map showing the risk of subsoil compaction in five classes was used for stratification. Measurements of bulk density, porosity, clay content and organic matter content were used to compute the relative bulk density and relative porosity, both expressed as a fraction of a threshold value. A subsoil was classified as overcompacted if either the relative bulk density exceeded 1 or the relative porosity was below 1. The sample data were used to estimate the means of the two subsoil compaction parameters and the overcompacted areal fraction. The estimated global means of relative bulk density and relative porosity were 0.946 and 1.090, respectively. The estimated areal fraction of the Netherlands with overcompacted subsoils was 43 %. The estimates per risk map unit showed two groups of map units: a low-risk group (units 1 and 2, covering only 4.6 % of the total area) and a high-risk group (units 3, 4 and 5). The estimated areal fraction of overcompacted subsoil was 0 % in the low-risk unit and 47 % in the high-risk unit. The map contains no information about where overcompacted subsoils occur. This was caused by the poor association of the risk map units 3, 4 and 5 with the subsoil compaction parameters and subsoil overcompaction. This can be explained by the lack of time for recuperation.

Self-assembly of colloids with magnetic caps

Energy Technology Data Exchange (ETDEWEB)

Novak, E.V., E-mail: ekaterina.novak@urfu.ru [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); Kantorovich, S.S. [Ural Federal University, Lenin Av. 51, Ekaterinburg (Russian Federation); University of Vienna, Sensengasse 8, Vienna (Austria)

2017-06-01

In our earlier work (Steinbach et al., 2016 ) we investigated a homogeneous system of magnetically capped colloidal particles that self-assembled via two structural patterns of different symmetry. The particles could form a compact, equilateral triangle with a three-fold rotational symmetry and zero dipole moment and a staggered chain with mirror symmetry with a net magnetisation perpendicular to the chain. The system exhibited a bistability already in clusters of three particles. Based on observations of a real magnetic particles system, analytical calculations and molecular dynamics simulations, it has been shown that the bistability is a result of an anisotropic magnetisation distribution with rotational symmetry inside the particles. The present study is a logical extension of the above research and forms a preparatory stage for the study of a self-assembly of such magnetic particles under the influence of an external magnetic field. Since the magnetic field is only an additive contribution to the total ground state energy, we can study the interparticle interaction energies of candidate ground state structures based on the field-free terms. - Highlights: • Analytical calculations of the energies of ground state candidates for colloids with magnetic caps. • Computer simulations confirmed the theoretical model. • The structural transition between ground states was found.

High-Pressure NMR and SAXS Reveals How Capping Modulates Folding Cooperativity of the pp32 Leucine-rich Repeat Protein.

Science.gov (United States)

Zhang, Yi; Berghaus, Melanie; Klein, Sean; Jenkins, Kelly; Zhang, Siwen; McCallum, Scott A; Morgan, Joel E; Winter, Roland; Barrick, Doug; Royer, Catherine A

2018-04-27

Many repeat proteins contain capping motifs, which serve to shield the hydrophobic core from solvent and maintain structural integrity. While the role of capping motifs in enhancing the stability and structural integrity of repeat proteins is well documented, their contribution to folding cooperativity is not. Here we examined the role of capping motifs in defining the folding cooperativity of the leucine-rich repeat protein, pp32, by monitoring the pressure- and urea-induced unfolding of an N-terminal capping motif (N-cap) deletion mutant, pp32-∆N-cap, and a C-terminal capping motif destabilization mutant pp32-Y131F/D146L, using residue-specific NMR and small-angle X-ray scattering. Destabilization of the C-terminal capping motif resulted in higher cooperativity for the unfolding transition compared to wild-type pp32, as these mutations render the stability of the C-terminus similar to that of the rest of the protein. In contrast, deletion of the N-cap led to strong deviation from two-state unfolding. In both urea- and pressure-induced unfolding, residues in repeats 1-3 of pp32-ΔN-cap lost their native structure first, while the C-terminal half was more stable. The residue-specific free energy changes in all regions of pp32-ΔN-cap were larger in urea compared to high pressure, indicating a less cooperative destabilization by pressure. Moreover, in contrast to complete structural disruption of pp32-ΔN-cap at high urea concentration, its pressure unfolded state remained compact. The contrasting effects of the capping motifs on folding cooperativity arise from the differential local stabilities of pp32, whereas the contrasting effects of pressure and urea on the pp32-ΔN-cap variant arise from their distinct mechanisms of action. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of temperature on volume change behaviour of statically compacted kaolin clay

Directory of Open Access Journals (Sweden)

Ileme Ogechi

2016-01-01

Full Text Available Several soils are subjected to high temperature due to the environment where they are located or activities around them. For instance, upper layer of soils in tropical regions, soils around geothermal structures, clay barriers around nuclear waste repository systems. Numerous studies have pointed out that high temperature affects the hydro-mechanical properties of soils. Notwithstanding already existing studies, the influence of temperature on soils is still a challenge, as most of these studies are soil specific and cannot be inferred as the behaviour of all soils. This paper presents an experimental study on the influence of temperature on the volume change behaviour of statically compacted kaolin clay. Compacted samples were tested at varying temperatures using a suction controlled oedometer cell. The influence of temperature on the magnitude of volumetric strain occurring during mechanical and thermal loading was investigated. The study showed that an increase in temperature increased the magnitude of volumetric strain of the soil on loading. Additionally, the results presented in the light of LC curve showed that an increase in temperature resulted in the contraction and a change in the position of the LC curve.

Soil physical land degradation processes

Science.gov (United States)

Horn, Rainer

2017-04-01

According to the European Soil Framework Directive (2006) soil compaction is besides water and wind erosion one of the main physical reasons and threats of soil degradation. It is estimated, that 32% of the subsoils in Europe are highly degraded and 18% moderately vulnerable to compaction. The problem is not limited to crop land or forest areas (especially because of non-site adjusted harvesting machines) but is also prevalent in rangelands and grassland, and even in so called natural non-disturbed systems. The main reasons for an intense increase in compacted agricultural or forested regions are the still increasing masses of the machines as well the increased frequency of wheeling under non favorable site conditions. Shear and vibration induced soil deformation enhances the deterioration of soil properties especially if the soil water content is very high and the internal soil strength very low. The same is true for animal trampling in combination with overgrazing of moist to wet pastures which subsequently causes a denser (i.e. reduced proportion of coarse pores with smaller continuity) but still structured soil horizons and will finally end in a compacted platy structure. In combination with high water content and shearing due to trampling therefore results in a complete muddy homogeneous soil with no structure at all. (Krümmelbein et al. 2013) Site managements of arable, forestry or horticulture soils requires a sufficiently rigid pore system which guarantees water, gas and heat exchange, nutrient transport and adsorption as well as an optimal rootability in order to avoid subsoil compaction. Such pore system also guarantees a sufficient microbial activity and composition in order to also decompose the plant etc. debris. It is therefore essential that well structured horizons dominate in soils with at best subangular blocky structure or in the top A- horizons a crumbly structure due to biological activity. In contrast defines the formation of a platy

Physical soil degradation in the Netherlands

NARCIS (Netherlands)

Boels, D.; Havinga, L.

1980-01-01

Soils used in agriculture are subjected to a wide variety of human activities. Soil tillage and soil impravement operations may loose the soil, while soil wetting due to rainfall, and farming operations as sowing, spraying, weed control and harvesting but also grazing cattle may compact the soil.

Phasing out of environmentally harmful subsidies. Consequences of the 2003 CAP reform

Energy Technology Data Exchange (ETDEWEB)

Schmid, Erwin; Hofreither, Markus F. [Institute for Sustainable Economic Development, Department of Economics and Social Sciences, University of Natural Resources and Applied Life Sciences Vienna (BOKU), Feistmantelstrasse 4, 1180 Vienna (Austria); Sinabell, Franz [Austrian Institute of Economic Research Vienna (WIFO), PO Box 91, 1103 Vienna (Austria)

2007-01-15

Subsidies linked to production have been classified as environmentally harmful by the OECD. A core element of the EU 2003 Common Agricultural Policy (CAP) reform is to decouple income support from production. This paper estimates the environmental consequences of this policy reform. An agricultural sector model using a modified version of the positive mathematical programming method depicts the complex natural, structural, and political relationships of Austrian farming. Changes in management measures can be analyzed with respect to their environmental effects by using appropriate indicators. Simulation results show that the 2003 CAP reform will reduce the average cost of production, and may improve environmental conditions regarding soil, water, and greenhouse gases when compared to a scenario without reform. Thus, the new CAP is likely to bring about outcomes which the previous reform (Agenda 2000) promised but did not deliver. (author)

Cradle Cap: Treatment

Science.gov (United States)

Cradle cap Treatment Cradle cap usually doesn't require medical treatment. It clears up on its own within a few months. In the meantime, wash ... tips can help you control and manage cradle cap. Gently rub your baby's scalp with your fingers ...

Permeability Characteristics of Compacted and Stabilized Clay with Cement, Peat Ash and Silica Sand

OpenAIRE

Seyed Esmaeil Mousavi; Leong Sing Wong

2016-01-01

The present paper investigates the influence of stabilization with cement, peat ash, and silica sand on permeability coefficient (kv) of compacted clay, using a novel approach to stabilize the clay with peat ash as a supplementary material of cement in the compacted and stabilized soil. In order to assess the mentioned influence, test specimens of both untreated and stabilized soil have been tested in the laboratory so that their permeability could be evaluated. Falling head and one dimension...

Production and quality control of optical elements for the end cap hadron calorimeter of the CMS setup

CERN Document Server

Abramov, V V; Korablev, A V; Korneev, Yu P; Krinitsyn, A N; Kryshkin, V I; Markov, A A; Talov, VV; Turchanovich, L K; Volkov, A A; Zaichenko, A A

2005-01-01

An end cap hadron calorimeter, in which scintillators with wavelength-shifting fibers are used as the active elements, has been designed for the compact muon spectrometer (CMS) now under construction at CERN. A total of 1368 optical elements containing 21 096 scintillators have already been manufactured. The production and quality control procedures for these optical elements are described. copy 2005 Pleiades Publishing, Inc.

Suscetibilidade de dois tipos de solo à compactação Compaction susceptibility of two classes of soil

Directory of Open Access Journals (Sweden)

Pedro H. Weirich Neto

2002-01-01

Full Text Available Com vistas ao aumento da produção agrícola, optou-se no Brasil, pelo acréscimo de área cultivada; para tal o uso indiscriminado da motomecanização mostrou-se eficiente em um primeiro momento, porém acarretando problemas à física do solo no decorrer dos anos. Paralelamente, práticas conservacionistas se fazem presentes, vide semeadura sob a palha (Plantio Direto, uma realidade no sul do Brasil. Sendo assim, avaliou-se a suscetibilidade de compactação de dois tipos de solo, ambos com sistema de semeadura sob a palha. Para dimensionar a suscetibilidade a compactação, utilizou-se ensaio de Proctor. Os solos foram ensaiados com e sem a presença de matéria orgânica livre. Os resultados demonstraram que para o Cambissolo, textura média, não houve diferença nos valores que representam a suscetibilidade, enquanto no Latossolo Vermelho, textura argilosa, não houve diferença entre a máxima densidade aparente, porém houve diferença significativa no conteúdo de água para a máxima densidade, o mesmo alterou-se de 0,249 g g-1 no ponto de máxima compactação no ensaio sem a presença de matéria orgânica livre, para 0,283 g g-1 no ponto de máxima compactação, quando da presença da matéria orgânica livre.For increasing agricultural production, Brazil opted to enlarge the cultivated area, and indiscriminate mechanization was efficient at the first moment, although it altered adversely the soil properties with the passage of time. At the same time, conservation practices, like the direct sowing under the straw (No Tillage were adopted which is a reality in Southern Brazil. Considering this, the susceptibility for compaction of two classes of soil was evaluated under no tillage system, with and without free organic matter. The Proctor test was used to measure the degree of compaction. The results of a medium texture Cambissol showed there was no difference in susceptibility for compaction. The clay textured Red Latossol, showed

Correction of resistance to penetration by pedofunctions and a reference soil water content

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Moacir Tuzzin de Moraes

2012-12-01

Full Text Available The soil penetration resistance is an important indicator of soil compaction and is strongly influenced by soil water content. The objective of this study was to develop mathematical models to normalize soil penetration resistance (SPR, using a reference value of gravimetric soil water content (U. For this purpose, SPR was determined with an impact penetrometer, in an experiment on a Dystroferric Red Latossol (Rhodic Eutrudox, at six levels of soil compaction, induced by mechanical chiseling and additional compaction by the traffic of a harvester (four, eight, 10, and 20 passes; in addition to a control treatment under no-tillage, without chiseling or additional compaction. To broaden the range of U values, SPR was evaluated in different periods. Undisturbed soil cores were sampled to quantify the soil bulk density (BD. Pedotransfer functions were generated correlating the values of U and BD to the SPR values. By these functions, the SPR was adequately corrected for all U and BD data ranges. The method requires only SPR and U as input variables in the models. However, different pedofunctions are needed according to the soil layer evaluated. After adjusting the pedotransfer functions, the differences in the soil compaction levels among the treatments, previously masked by variations of U, became detectable.

Hydro-mechanical improvement of the cap cover of a surface landfill for low and intermediate level radioactive waste short life time

International Nuclear Information System (INIS)

Verstaevel, Matthieu

2015-01-01

This study related to the Manche storage center (CSM), one of the first landfill in the world dedicated to low and intermediate radioactive waste short-live time. The researches considered in this thesis supported by industrial companies, focus on the hydraulic study of cap cover materials of the site, and their hydro-mechanical improvement. The aim is to improve their impermeability in order to be substituted to the geo-membrane as cap cover liner. A specification imposed by Andra was to consider a solution of the re-use of the in situ material by adding of additive. The initial material is a sandy silt, a material with a significant proportion of fines. In the literature there are many studies on the mechanical improvement of fine materials (applications to road infrastructure) and the treatment of sandy materials by adding a fine fraction (constitution of waterproof barriers). On the other hand there are very few studies on the impermeability improvement of fine soils. A physical tests campaign on treated materials with bentonite was carried out at various treatment rates. The results showed that the addition of additive induces a decrease in optimum dry unit weight for a normal Proctor compaction energy and increases their optimum water content. In addition, the susceptibility to erosion, internal or external, observed during oedo-permeameter test was assessed from various stability criteria available in the literature. Unlike the treatment of soil for road embankments, the increase of the material stiffness is not wanted and flexibility is preferred what is observed with the treatment tested. The comparative hydraulic conductivity of the untreated and treated materials were measured. In this study different devices (oedo-permeameter, permeameters, triaxial device) were used. The influence of the treatment rate of the material on the decrease of the hydraulic conductivity was observed. Four large scale experimentations were designed; they should be monitored

The Snow Must Go On: Ground Ice Encasement, Snow Compaction and Absence of Snow Differently Cause Soil Hypoxia, CO2 Accumulation and Tree Seedling Damage in Boreal Forest.

Science.gov (United States)

Martz, Françoise; Vuosku, Jaana; Ovaskainen, Anu; Stark, Sari; Rautio, Pasi

2016-01-01

At high latitudes, the climate has warmed at twice the rate of the global average with most changes observed in autumn, winter and spring. Increasing winter temperatures and wide temperature fluctuations are leading to more frequent rain-on-snow events and freeze-thaw cycles causing snow compaction and formation of ice layers in the snowpack, thus creating ice encasement (IE). By decreasing the snowpack insulation capacity and restricting soil-atmosphere gas exchange, modification of the snow properties may lead to colder soil but also to hypoxia and accumulation of trace gases in the subnivean environment. To test the effects of these overwintering conditions changes on plant winter survival and growth, we established a snow manipulation experiment in a coniferous forest in Northern Finland with Norway spruce and Scots pine seedlings. In addition to ambient conditions and prevention of IE, we applied three snow manipulation levels: IE created by artificial rain-on-snow events, snow compaction and complete snow removal. Snow removal led to deeper soil frost during winter, but no clear effect of IE or snow compaction done in early winter was observed on soil temperature. Hypoxia and accumulation of CO2 were highest in the IE plots but, more importantly, the duration of CO2 concentration above 5% was 17 days in IE plots compared to 0 days in ambient plots. IE was the most damaging winter condition for both species, decreasing the proportion of healthy seedlings by 47% for spruce and 76% for pine compared to ambient conditions. Seedlings in all three treatments tended to grow less than seedlings in ambient conditions but only IE had a significant effect on spruce growth. Our results demonstrate a negative impact of winter climate change on boreal forest regeneration and productivity. Changing snow conditions may thus partially mitigate the positive effect of increasing growing season temperatures on boreal forest productivity.

Soil weight (lbf/ft3) at Hanford waste storage locations (2 volumes)

International Nuclear Information System (INIS)

Pianka, E.W.

1994-12-01

Hanford Reservation waste storage tanks are fabricated in accordance with approved construction specifications. After an underground tank has been constructed in the excavation prepared for it, soil is place around the tank and compacted by an approved compaction procedure. To ensure compliance with the construction specifications, measurements of the soil compaction are taken by QA inspectors using test methods based on American Society for the Testing and Materials (ASTM) standards. Soil compaction tests data taken for the 241AP, 241AN, and 241AW tank farms constructed between 1978 and 1986 are included. The individual data values have been numerically processed to obtain average soil density values for each of these tank farms

Long-term evaluation for engineered capping (cover) of radioactive repository or landfill

International Nuclear Information System (INIS)

Mohd Jamil Hashim; Mohd Abdul Wahab Yusof

2010-01-01

This paper discussed the long-term evaluation of engineered capping for radioactive repository. It was done to gather knowledge and understand the suitability of granitic residual soil. Its resistance to hydrologic cycle and durability through a period of 100 to 300 years was checked. A hydrological program was used with forecast weather and manual checking all layers for hydraulic gradient to verify the results. Overall result shown that the grantic residual soil is able to last a few centuries before surcome to infiltration. (author)

Influence of the chemical, physical and mineralogical characteristics on the three latosoils compacting

International Nuclear Information System (INIS)

Fernandes, Rafael Braganca Alves; Fontes, Luiz Eduardo Ferreira; Costa, Liovando Marciano da

1997-01-01

This work studies the behavior of three brazilian latosoils (Purple, Una and yellow latosoils) concerning to the tendency of compacting, by using the trail analysis for evaluation of the physical, chemical, mineralogical and other compacting estimation effects on this process. Two conditions of soil use were considered: intensive cultivation, with field evaluation which indicates the compacting and not worked area, with natural forest or old and abandoned reforesting

Compact detector for radon and radon daughter products

International Nuclear Information System (INIS)

Alter, H.W.; Oswald, R.A.

1986-01-01

This invention provides an improved compact track registration detector for radon gas. The detector comprises a housing having an open mouth, a bottom, and side walls; track registration means, supported inside the housing, which forms damage tracks along paths traversed by alpha particles; a microporous filter positioned across the mouth of the housing to prevent entry of radon daughters and particulate matter; and a cap that may be placed on the mouth of the housing to retain the filter. The housing has internal wall surfaces dimensioned to optimize the registration of alpha particles from radon and radon daughters present in the housing

Evaluation of Pigeon Pea Lines for Biological Soil Decompaction

Directory of Open Access Journals (Sweden)

Rodolfo Godoy

2009-01-01

Full Text Available Soil decompaction is generally achieved through mechanical cultivation practices; however biological processes can significantly add to this process through root growth, development, and later senescence. This study was carried out in Piracicaba, SP, Brazil and had the purpose of selecting, among forty one pure pigeon pea lines, the most efficient genotypes that promote soil decompaction by roots penetrating compacted soil layers. Utilizing artificially compacted 30 mm high soil blocks, in a series of experiments, these lines were compared to the cultivar Fava Larga taken as a standard. Three lines were preliminarily selected out of the initial group, and afterwards, in more detailed screenings by monitoring soil resistance to penetration and also evaluating the behavior of Tanzania grass plants seeded after pigeon pea, two of them, g5-94 and g8-95, were selected as possessing the most fit root system to penetrate compacted soil layers.

In situ subsoil stress-strain behaviour in relation to soil precompression stress

DEFF Research Database (Denmark)

Keller, T; Arvidsson, J; Schjønning, Per

2012-01-01

is assumed to be elastic and reversible as long as [sigma] work examined soil stress-strain behavior as measured in situ during wheeling experiments and related it to the stress-strain behavior and [sigma]pc measured on soil cores in uniaxial compression tests in the laboratory. The data......Soil compaction negatively influences many important soil functions, including crop growth. Compaction occurs when the applied stress, [sigma], overcomes the soil strength. Soil strength in relation to compaction is typically expressed by the soil precompression stress, [sigma]pc. Deformation...... analyzed were from a large number of wheeling experiments carried out in Sweden and Denmark on soils with a wide range of texture. Contradicting the concept of precompression stress, we observed residual strain, [Latin Small Letter Open E]res, at [sigma

Structural changes of eIF4E upon binding to the mRNA 5' monomethylguanosine and trimethylguanosine Cap.

Science.gov (United States)

Rutkowska-Wlodarczyk, Izabela; Stepinski, Janusz; Dadlez, Michal; Darzynkiewicz, Edward; Stolarski, Ryszard; Niedzwiecka, Anna

2008-03-04

Recognition of the 5' cap by the eukaryotic initiation factor 4E (eIF4E) is the rate-limiting step in the ribosome recruitment to mRNAs. The regular cap consists of 7-monomethylguanosine (MMG) linked by a 5'-5' triphosphate bridge to the first transcribed nucleoside, while some primitive eukaryotes possess a N (2), N (2),7-trimethylguanosine (TMG) cap structure as a result of trans splicing. Mammalian eIF4E is highly specific to the MMG form of the cap in terms of association constants and thermodynamic driving force. We have investigated conformational changes of eIF4E induced by interaction with two cap analogues, 7-methyl-GTP and N (2), N (2),7-trimethyl-GTP. Hydrogen-deuterium exchange and electrospray mass spectrometry were applied to probe local dynamics of murine eIF4E in the apo and cap-bound forms. The data show that the cap binding induces long-range conformational changes in the protein, not only in the cap-binding pocket but also in a distant region of the 4E-BP/eIF4G binding site. Formation of the complex with 7-methyl-GTP makes the eIF4E structure more compact, while binding of N (2), N (2),7-trimethyl-GTP leads to higher solvent accessibility of the protein backbone in comparison with the apo form. The results suggest that the additional double methylation at the N (2)-amino group of the cap causes sterical effects upon binding to mammalian eIF4E which influence the overall solution dynamics of the protein, thus precluding formation of a tight complex.

Forest Soil Productivity on the Southern Long-Term Soil Productivity Sites at Age 5

Science.gov (United States)

D. Andrew Scott; Allan E. Tiarks; Felipe G. Sanchez; Michael Elliott-Smith; Rick Stagg

2004-01-01

Forest management operations have the potential to reduce soil productivity through organic matter and nutrient removal and soil compaction. We measured pine volume, bulk density, and soil and foliar nitrogen and phosphorus at age 5 on the 13 southern Long-Term Soil Productivity study sites. The treatments were organic matter removal [bole only (BO), whole tree (WT),...

Influence of Compacting Rate on the Properties of Compressed Earth Blocks

Directory of Open Access Journals (Sweden)

Humphrey Danso

2016-01-01

Full Text Available Compaction of blocks contributes significantly to the strength properties of compressed earth blocks. This paper investigates the influence of compacting rates on the properties of compressed earth blocks. Experiments were conducted to determine the density, compressive strength, splitting tensile strength, and erosion properties of compressed earth blocks produced with different rates of compacting speed. The study concludes that although the low rate of compaction achieved slightly better performance characteristics, there is no statistically significant difference between the soil blocks produced with low compacting rate and high compacting rate. The study demonstrates that there is not much influence on the properties of compressed earth blocks produced with low and high compacting rates. It was further found that there are strong linear correlations between the compressive strength test and density, and density and the erosion. However, a weak linear correlation was found between tensile strength and compressive strength, and tensile strength and density.

Subsoil compaction assessed by visual evaluation and laboratory methods

DEFF Research Database (Denmark)

Obour, Peter Bilson; Schjønning, Per; Peng, Yi

2017-01-01

. The soil profiles were evaluated at the same time as soil cores were sampled at 0.3, 0.5 and 0.7 m depth. In the laboratory, we measured water content, total porosity, air-filled porosity (ea), air permeability (ka) and calculated pore organization indices (PO1 = ka/ea and PO2 = ka/ea 2) on the soil cores...... and continuity, especially at 0.3 and 0.5 m depths. Detailed measurements of the anisotropy of soil pore characteristics at 0.3–0.4 m depth showed that for PO2 (pore size distribution) and blocked air-filled porosity the control soil was significantly anisotropic. Although compaction with the 8 Mg wheel load...

Impact of Site Disturbances from Harvesting and Logging on Soil Physical Properties and Pinus kesiya Tree Growth.

Science.gov (United States)

Missanjo, Edward; Kamanga-Thole, Gift

2014-01-01

A study was conducted to determine the impacts of soil disturbance and compaction on soil physical properties and tree growth and the effectiveness of tillage in maintaining or enhancing site productivity for intensively managed Pinus kesiya Royle ex Gordon sites in Dedza, Malawi. The results indicate that about fifty-two percent of the area of compacted plots was affected by the vehicular traffic. Seventy percent of the trees were planted on microsites with some degree of soil disturbance. Soil bulk density at 0-20 cm depth increased from 0.45 to 0.66 Mg m(-3) in the most compacted portions of traffic lanes. Soil strength in traffic lanes increased at all 60 cm depth but never exceeded 1200 kPa. Volumetric soil water content in compacted traffic lanes was greater than that in noncompacted soil. Total soil porosity decreased 13.8% to 16.1% with compaction, while available water holding capacity increased. The study revealed no detrimental effects on tree height and diameter from soil disturbance or compaction throughout the three growing season. At the ages of two and three, a tree volume index was actually greater for trees planted on traffic lanes than those on nondisturbed soil.

STRAIN-STRESS DISTRIBUTION OF “HOMOGENEOUS” SOIL MASS DURING THE LOAD TRANSMITTED THROUGH THE LIMITED AREA IN THE PLAN, APPLIED INSIDE THE ELASTIC HOMOGENEOUS SOIL MASS

Directory of Open Access Journals (Sweden)

BOLSHAKOV V. I.

2017-03-01

Full Text Available Summary. Based on the current understanding of the piles work in clayey soils; that is forming during driving process a compacted core (compacted platform in the pile tip plane and transferring the load from the pile (from the piling foundation not through the pile tip but through the pressed core (compacted platform, the stress in the soil mass by the load applied inside the elastic half-space is determined with the change in the calculated scheme of load transferring to the “homogeneous” soil mass.

Growth, reproduction and biochemical toxicity of chlorantraniliprole in soil on earthworms (Eisenia fetida).

Science.gov (United States)

Liu, Tong; Wang, Xiuguo; Chen, Dan; Li, Yiqiang; Wang, Fenglong

2018-04-15

Diamide insecticides have become the fourth most commonly used insecticide class in the world. Chlorantraniliprole (CAP) is a first-generation diamide insecticide with broad application potential. In this experiment, the eco-toxicity of CAP in soil at 0.1, 1.0, 5.0 and 10.0mg/kg on earthworms (Eisenia fetida) was evaluated during a 42 d exposure. More specifically, the environmental fate and transport of CAP between soil and earthworms was monitored during the exposure period. The present results indicated that the CAP contents of 0.1, 1.0, 5.0 and 10.0mg/kg treatments decreased to no more than 20% in the soil after 42 d of exposure. The accumulation of CAP in earthworms was 0.03, 0.58, 4.28 and 7.21mg/kg earthworm (FW) at 0.1, 1.0, 5.0 and 10.0mg/kg after 42 d of exposure. At 0.1mg/kg and 1.0mg/kg, CAP had no effect on earthworms during the exposure period. The weight of earthworms was significantly reduced at 5.0 and 10.0mg/kg at 28 and 42 days after CAP application. After the 14th day, CAP induced excess production of reactive oxygen species (ROS) at 5.0 and 10.0mg/kg, resulting in oxidative damage to biomacromolecules. We believe that CAP has a high risk potential for earthworms when used at 5.0 and 10.0mg/kg. Copyright © 2017 Elsevier Inc. All rights reserved.

Estimativa da susceptibilidade à compactação e do suporte de carga do solo com base em propriedades físicas de solos do Rio Grande do Sul Estimating soil susceptibility to compaction and load support capacity based on physical parameters of soils from Rio Grande do Sul State

Directory of Open Access Journals (Sweden)

Luis Eduardo Akiyoshi Sanches Suzuki

2008-06-01

Full Text Available O conhecimento das relações entre propriedades físicas e mecânicas do solo pode contribuir no desenvolvimento de funções de pedotransferência, que permitam estimar outras propriedades do solo de difícil mensuração. Neste trabalho, objetivou-se avaliar a relação entre a susceptibilidade à compactação e o suporte de carga com propriedades físicas de solos do sul do Brasil. Foram avaliadas a resistência à penetração, a umidade, a densidade e a compressibilidade de seis solos. A resistência à penetração pode ser estimada pelo modelo que considera a umidade e densidade do solo. Solos com maior densidade inicial apresentaram menor susceptibilidade à compactação e menor deformação, quando submetidos a pressões externas. Quanto maior a resistência do solo à penetração, menor é a deformação e maior é a capacidade de suporte de carga, embora isso não indique solos com qualidade física adequada para as culturas; quanto maior a deformação do solo, maior a susceptibilidade à compactação e menor a capacidade de suporte de carga. A susceptibilidade de um solo à compactação e sua capacidade de suporte de carga podem ser estimadas, respectivamente, pela densidade inicial e pela resistência do solo à penetração.Quantifying the relationship between physical and mechanical soil properties can contribute to the development of pedotransfer functions that allow estimating hard-to-measure soil properties. The objective of this study was to evaluate the interrelations between susceptibility to compaction and load support with some physical properties of soils from Southern Brazil. Penetration resistance, moisture, bulk density and compressibility of six soils were evaluated. In a model including soil moisture and bulk density as independent variables, the relation with penetration resistance values obtained in the field was high. Soils with higher initial bulk density were less susceptible to compaction and exhibited

Fungi in coastal tableland soils of northeastern Brazil : Preliminary results

NARCIS (Netherlands)

Araujo, QR; Bezerra, JL; Faleiro, RG; Bezerra, KMT; Menezes, PV; Faleiro, ASG; Ogram, AV; Al-Agely, A; Comerford, NB

2004-01-01

Soil compaction causes reduced agricultural production due to limited root development resulting in reduced water and nutrient access. This is particularly true of soils of the Brazilian tablelands (similar to200000 km(2)) that are characterized by a naturally occurring compact subsoil horizon. Most

Soil Penetration by Earthworms and Plant Roots--Mechanical Energetics of Bioturbation of Compacted Soils.

Directory of Open Access Journals (Sweden)

Siul Ruiz

Full Text Available We quantify mechanical processes common to soil penetration by earthworms and growing plant roots, including the energetic requirements for soil plastic displacement. The basic mechanical model considers cavity expansion into a plastic wet soil involving wedging by root tips or earthworms via cone-like penetration followed by cavity expansion due to pressurized earthworm hydroskeleton or root radial growth. The mechanical stresses and resulting soil strains determine the mechanical energy required for bioturbation under different soil hydro-mechanical conditions for a realistic range of root/earthworm geometries. Modeling results suggest that higher soil water content and reduced clay content reduce the strain energy required for soil penetration. The critical earthworm or root pressure increases with increased diameter of root or earthworm, however, results are insensitive to the cone apex (shape of the tip. The invested mechanical energy per unit length increase with increasing earthworm and plant root diameters, whereas mechanical energy per unit of displaced soil volume decreases with larger diameters. The study provides a quantitative framework for estimating energy requirements for soil penetration work done by earthworms and plant roots, and delineates intrinsic and external mechanical limits for bioturbation processes. Estimated energy requirements for earthworm biopore networks are linked to consumption of soil organic matter and suggest that earthworm populations are likely to consume a significant fraction of ecosystem net primary production to sustain their subterranean activities.

Curvas de compactação de um Latossolo Vermelho-Amarelo: com e sem reúso de amostras Soil compaction curves of an oxissol: with and without reuse of samples

Directory of Open Access Journals (Sweden)

Fabricio T. Ramos

2013-02-01

Full Text Available A curva de compactação do solo é determinada pelo ensaio de Proctor, normal ou modificado, amplamente empregado na engenharia civil; entretanto, seu uso agronômico apresenta limitações já que a configuração da curva parte do reúso de uma única amostra, desconsiderando a estrutura original do solo. Diante disto, objetivou-se avaliar a configuração da curva de compactação a partir do reúso e não reúso de amostras de um Latossolo Vermelho-Amarelo considerando-se diferentes sistemas de manejo. Verificou-se, ao comparar o procedimento com e sem reúso da amostra que, independentemente dos manejos e camadas avaliadas, foram obtidas diferentes curvas de compactação do solo. Por outro lado, o procedimento com reúso aumenta os valores de densidade do solo pela fragmentação dos agregados e reorganização das suas partículas. Portanto, para fins agrícola a curva de compactação é adequadamente caracterizada sem reúso de amostras visto que, neste ensaio, os agregados da amostra não são totalmente fracionados, sejam eles oriundos do solo sob vegetação nativa ou de áreas antropizadas.The soil compaction curve is determined by the Proctor test, normal or modified, widely used in civil engineering, however, its use has agronomic limitations, since the configuration of the curved part of the reuse of a single sample, disregarding the original soil structure. In this context, the objective of the study was to evaluate the configuration of the compaction curve based on with and without reuse of samples of an Oxissol, considering different management systems. While comparing the procedure with and without reuse of the sample, it was found that regardless of managements and layers evaluated, curves of soil compaction obtained were different. Furthermore, the procedure to reuse samples increases the density of the soil due to fragmentation of the aggregates and reorganization of its particles. Thus, for agricultural purposes, the

Innovative designs for low-level nuclear waste disposal trenches

International Nuclear Information System (INIS)

Nowatzki, E.A.; Armstrong, G.; McCray, J.

1985-01-01

Shallow land burial of low-level nuclear wastes presents many problems that are within the scope of civil engineering analysis and design. These include groundwater seepage, surface water runoff and collection, and the subsidence of trench backfills. Unfortunately, at the time the first disposal sites were being developed, major emphasis was placed on the health-physics aspects of the problem with the result that many of the civil engineering aspects were overlooked and severe problems relating to site integrity exist today. This paper presents the results of a U.S. Nuclear Regulatory Commission (USNRC) sponsored research project conducted at the University of Arizona, Tucson, Arizona, to assess trench cap design from the viewpoint of stability, water infiltration, and economy. Full-scale trenches were constructed that incorporated four different designs. These designs range from a relatively simple cap consisting of engineered backfill with a sloping, compacted soil crown to a more complex cap-crown system that incorporates compacted backfill and a steel reinforced soil-cement cap with an overlaying ''wick'' drain. The results of structural and hydrological monitoring over a period of approximately 15 months are presented. Recommendations are made regarding standard design criteria for future sites based on the results of this research

Frost Heave in Colloidal Soils

KAUST Repository

Peppin, Stephen; Majumdar, Apala; Style, Robert; Sander, Graham

2011-01-01

We develop a mathematical model of frost heave in colloidal soils. The theory accountsfor heave and consolidation while not requiring a frozen fringe assumption. Two solidificationregimes occur: a compaction regime in which the soil consolidates

Sustainable management of agriculture activity on areas with soil vulnerability to compaction trough a developed decision support system (DSS)

Science.gov (United States)

Moretto, Johnny; Fantinato, Luciano; Rasera, Roberto

2017-04-01

One of the main environmental effects of agriculture is the negative impacts on areas with soil vulnerability to compaction and undersurface water derived from inputs and treatment distributions. A solution may represented from the "Precision Farming". Precision Farming refers to a management concept focusing on (near-real time) observation, measurement and responses to inter- and intra-variability in crops, fields and animals. Potential benefits may include increasing crop yields and animal performance, cost and labour reduction and optimisation of process inputs, all of which would increase profitability. At the same time, Precision Farming should increase work safety and reduce the environmental impacts of agriculture and farming practices, thus contributing to the sustainability of agricultural production. The concept has been made possible by the rapid development of ICT-based sensor technologies and procedures along with dedicated software that, in the case of arable farming, provides the link between spatially-distributed variables and appropriate farming practices such as tillage, seeding, fertilisation, herbicide and pesticide application, and harvesting. Much progress has been made in terms of technical solutions, but major steps are still required for the introduction of this approach over the common agricultural practices. There are currently a large number of sensors capable of collecting data for various applications (e.g. Index of vegetation vigor, soil moisture, Digital Elevation Models, meteorology, etc.). The resulting large volumes of data need to be standardised, processed and integrated using metadata analysis of spatial information, to generate useful input for decision-support systems. In this context, a user-friendly IT applications has been developed, for organizing and processing large volumes of data from different types of remote sensing and meteorological sensors, and for integrating these data into user-friendly farm management support

The taste of soil: chemical investigation of soil, grape and wine in the Sopron wine region (Hungary)

Science.gov (United States)

Hofmann, Tomás; Horvàth, Imre; Bidló, András; Hofmann, Eszther

2015-04-01

The taste of soil: chemical investigation of soil, grape and wine in the Sopron wine region (Hungary) The Sopron wine region is one of the most significant and historical wine-producing regions of Hungary. 1800 hectares out of the total area of 4300 hectares of the wine region are used for grape cultivation. Kékfrankos (Blue Frankish) is the most frequent grape variety (60%) nevertheless other varieties are also grown here (including Zweigelt, Merlot, Cabernet Franc, Portugieser and Sauvignon Blanc). In this study preliminary results of the chemical analyses involving soil, grape and wine are presented, which could provide a future basis for a comprehensive terroir research in the wine region. As soil is the premanent home of grapevine, its quality is highly influencing for the growth of the plants and grape berries, and also determines future organoleptic characteristics of the wines. The investigated basic soil parameters included humus content, transition, soil structure, compactness, roots, skeletal percent, color, physical assortment, concretion, soil defects. Laboratory measurements involved the determination of pH, carbonated lime content, humus content, ammonium lactate-acetic acid soluble P and K content, KCl soluble Ca and Mg content, EDTA and DTPA soluble Cu, Fe, Mn and Zn content. Soil samples were also investigated for heavy metal contents using ICP-OES method (Thermo Scientific iCAP 7000 Series). By the use of thermoanalytical measurements (Mettler Toledo TGA/DSC 1 type thermogravimeter, 5°C/min, air atmosphere, 25-1000°C) the mineral composition of the soils was evaluated. Regarding major aroma compounds in grape berries and wine, the concentrations of organic acids (tartaric-, acetic-, succinic-, malic-, lactic acid), methanol, ethanol, glycerine, glucose and fructose were determined by high performance liquid chromatography (Shimadzu LC-20 HPLC equipment with DAD and RID detection). The density, titratable acidity, pH and total extractive

Enhanced Cover Assessment Project:Soil Manipulation and Revegetation Tests

Energy Technology Data Exchange (ETDEWEB)

Waugh, W. Joseph [Navarro Research and Engineering, Inc.; Albright, Dr. Bill [Desert Research Inst. (DRI), Reno, NV (United States); Benson, Dr. Craig [University of Wisconsin-Madison

2014-02-01

The U.S. Department of Energy Office of Legacy Management is evaluating methods to enhance natural changes that are essentially converting conventional disposal cell covers for uranium mill tailings into water balance covers. Conventional covers rely on a layer of compacted clayey soil to limit exhalation of radon gas and percolation of rainwater. Water balance covers rely on a less compacted soil “sponge” to store rainwater, and on soil evaporation and plant transpiration (evapotranspiration) to remove stored water and thereby limit percolation. Over time, natural soil-forming and ecological processes are changing conventional covers by increasing hydraulic conductivity, loosening compaction, and increasing evapotranspiration. The rock armor on conventional covers creates a favorable habitat for vegetation by slowing soil evaporation, increasing soil water storage, and trapping dust and organic matter, thereby providing the water and nutrients needed for plant germination, survival, and sustainable transpiration. Goals and Objectives Our overall goal is to determine if allowing or enhancing these natural changes could improve cover performance and reduce maintenance costs over the long term. This test pad study focuses on cover soil hydrology and ecology. Companion studies are evaluating effects of natural and enhanced changes in covers on radon attenuation, erosion, and biointrusion. We constructed a test cover at the Grand Junction disposal site to evaluate soil manipulation and revegetation methods. The engineering design, construction, and properties of the test cover match the upper three layers of the nearby disposal cell cover: a 1-foot armoring of rock riprap, a 6-inch bedding layer of coarse sand and gravel, and a 2-foot protection layer of compacted fine soil. The test cover does not have a radon barrier—cover enhancement tests leave the radon barrier intact. We tested furrowing and ripping as means for creating depressions parallel to the slope

Shaping an Optimal Soil by Root-Soil Interaction.

Science.gov (United States)

Jin, Kemo; White, Philip J; Whalley, William R; Shen, Jianbo; Shi, Lei

2017-10-01

Crop production depends on the availability of water and mineral nutrients, and increased yields might be facilitated by a greater focus on roots-soil interactions. Soil properties affecting plant growth include drought, compaction, nutrient deficiency, mineral toxicity, salinity, and submergence. Plant roots respond to the soil environment both spatially and temporally by avoiding stressful soil environments and proliferating in more favorable environments. We observe that crops can be bred for specific root architectural and biochemical traits that facilitate soil exploration and resource acquisition, enabling greater crop yields. These root traits affect soil physical and chemical properties and might be utilized to improve the soil for subsequent crops. We argue that optimizing root-soil interactions is a prerequisite for future food security. Copyright © 2017 Elsevier Ltd. All rights reserved.

A nanobody targeting the F-actin capping protein CapG restrains breast cancer metastasis.

Science.gov (United States)

Van Impe, Katrien; Bethuyne, Jonas; Cool, Steven; Impens, Francis; Ruano-Gallego, David; De Wever, Olivier; Vanloo, Berlinda; Van Troys, Marleen; Lambein, Kathleen; Boucherie, Ciska; Martens, Evelien; Zwaenepoel, Olivier; Hassanzadeh-Ghassabeh, Gholamreza; Vandekerckhove, Joël; Gevaert, Kris; Fernández, Luis Ángel; Sanders, Niek N; Gettemans, Jan

2013-12-13

Aberrant turnover of the actin cytoskeleton is intimately associated with cancer cell migration and invasion. Frequently however, evidence is circumstantial, and a reliable assessment of the therapeutic significance of a gene product is offset by lack of inhibitors that target biologic properties of a protein, as most conventional drugs do, instead of the corresponding gene. Proteomic studies have demonstrated overexpression of CapG, a constituent of the actin cytoskeleton, in breast cancer. Indirect evidence suggests that CapG is involved in tumor cell dissemination and metastasis. In this study, we used llama-derived CapG single-domain antibodies or nanobodies in a breast cancer metastasis model to address whether inhibition of CapG activity holds therapeutic merit. We raised single-domain antibodies (nanobodies) against human CapG and used these as intrabodies (immunomodulation) after lentiviral transduction of breast cancer cells. Functional characterization of nanobodies was performed to identify which biochemical properties of CapG are perturbed. Orthotopic and tail vein in vivo models of metastasis in nude mice were used to assess cancer cell spreading. With G-actin and F-actin binding assays, we identified a CapG nanobody that binds with nanomolar affinity to the first CapG domain. Consequently, CapG interaction with actin monomers or actin filaments is blocked. Intracellular delocalization experiments demonstrated that the nanobody interacts with CapG in the cytoplasmic environment. Expression of the nanobody in breast cancer cells restrained cell migration and Matrigel invasion. Notably, the nanobody prevented formation of lung metastatic lesions in orthotopic xenograft and tail-vein models of metastasis in immunodeficient mice. We showed that CapG nanobodies can be delivered into cancer cells by using bacteria harboring a type III protein secretion system (T3SS). CapG inhibition strongly reduces breast cancer metastasis. A nanobody-based approach offers

Teor de carbono orgânico e a susceptibilidade à compactação de um Nitossolo e um Argissolo Organic carbon content and susceptibility to compaction of Hapludalf and Hapludox soils

Directory of Open Access Journals (Sweden)

João A. Braida

2010-02-01

Full Text Available O acúmulo de matéria orgânica pode aumentar a resistência do solo à compactação, diminuindo sua magnitude ou seus efeitos. O objetivo do presente trabalho foi estudar as implicações do acúmulo de matéria orgânica no solo sobre sua susceptibilidade à compactação medida pelo coeficiente de compressão. Buscou-se estabelecer relações entre o teor de carbono orgânico e o coeficiente de compressão do solo. Utilizaram-se amostras de solo coletadas em um Argissolo Vermelho-Amarelo distrófico arênico e de um Nitossolo Vermelho distrófico latossólico, ambos contendo ampla variação do teor de carbono orgânico (CO. As amostras, com umidade equilibrada em quatro tensões de água, foram submetidas ao ensaio de adensamento uniaxial confinado, mediante cargas normais de 12,5, 25, 50, 100, 200, 400, 800 e 1600 kPa e se determinando o coeficiente de compressão plástica; definiram-se, também, o teor de carbono orgânico, a densidade do solo, a porosidade e o grau de saturação com água das amostras. O teor de carbono orgânico afeta o coeficiente de compressão do solo; no entanto, a magnitude e o tipo de efeito são dependentes da textura do solo e de seus efeitos sobre a retenção de água, a coesão e a densidade do solo.Organic matter accumulation can increase soil resistance to compaction, decreasing the compaction magnitude or its effects. The objective of this study was to establish the effect of soil organic matter accumulation on the compressibility index, which corresponds to soil susceptibility to compaction. The study was performed using samples collected from a Hapludalf and a Hapludox soils in southern Brazil, both having a significant variation in soil organic carbon (SOC content. Soil compressibility tests were performed under confined conditions, in a uniaxial apparatus by using normal loads of 12.5, 25, 50, 100, 200, 400, 800 and 1600 kPa, and the compressibility index (Cc was calculated. Soil organic carbon

Soil erosion and its control in Chile - An overview

International Nuclear Information System (INIS)

Ellies, A.

2000-01-01

Accelerate erosion in Chile is a consequence from land use that degrade soil such as compaction, loss of organic matter and soil structure. The erosion is favored by the very hilly landscape of the country that increases erosivity index and the high erodibility given by an elevated annual rate of rainfall with irregular distribution. Several experiences have demonstrated that adequate crop management and crop rotations can minimize erosion. The most effective control is achieved conserving and improving soil structure with management systems that include regular use of soil-improving crops, return of crop residues and tillage practices, thus avoiding unnecessary breakdown soil or compacted soil structure. Conservation tillage increased organic matter levels improving stabile soil structure, aeration and infiltration. (author) [es

Introduction to the special issue on experiences with the impact and prevention of subsoil compaction in the European Union

NARCIS (Netherlands)

Akker, van den J.J.H.; Arvidsson, J.; Horn, R.

2003-01-01

The papers in this special issue present results of the European Union (EU) concerted action ¿Experiences with the impact of subsoil compaction on soil crop growth and environment and ways to prevent subsoil compaction¿. The results and conclusions of earlier research on subsoil compaction are

/sup 58,60,62/Ni (. cap alpha. ,p) three--nucleon transfer reactions and. cap alpha. optical potential ambiguities

Energy Technology Data Exchange (ETDEWEB)

Yuanda, Wang; Xiuming, Bao; Zhiqiang, Mao; Rongfang, Yuan; Keling, Wen; Binyin, Huang; Zhifu, Wang; Shuming, Li; Jianan, Wang; Zuxun, Sun; others, and

1985-11-01

The differential cross sections are measured using 26.0 MeV ..cap alpha.. particle for /sup 58,62/Ni(..cap alpha.., ..cap alpha..) /sup 58,62/Ni and /sup 58,62/Ni(..cap alpha..,p) /sup 61,65/Cu reactions as well as 25.4 MeV ..cap alpha.. particle for /sup 60/Ni(..cap alpha.., ..cap alpha..)/sup 69/Ni and /sup 60/Ni(..cap alpha.., p)/sup 63/Cu reactions. Consistent calculations with optical model and ZR DWBA are made for (..cap alpha.., ..cap alpha..) and (..cap alpha.., p) reactions by using of single, two, three and four nucleon optical potential parameters. For elastic scattering due to the ..cap alpha.. optical potential ambiguities, all the above optical potential can reproduce the experimental angular distributions. However, the single, two and three nucleon potential, including the Baird's mass systematics and the Chang's energy systematics of ..cap alpha.. potentials, obviously can not provide a reasonable fitting with the (..cap alpha..,p) reaction experimental data. Only the results from the four nucleon potential is in good agreement with the (..cap alpha..,p) reaction experimental data. This reveals that in the ..cap alpha..-particle induced transfer reactions, the real depth of the ..cap alpha..-nucleus optical potential should be rather deep.

How does the antagonism between capping and anti-capping proteins affect actin network dynamics?

International Nuclear Information System (INIS)

Hu Longhua; Papoian, Garegin A

2011-01-01

Actin-based cell motility is essential to many biological processes. We built a simplified, three-dimensional computational model and subsequently performed stochastic simulations to study the growth dynamics of lamellipodia-like branched networks. In this work, we shed light on the antagonism between capping and anti-capping proteins in regulating actin dynamics in the filamentous network. We discuss detailed mechanisms by which capping and anti-capping proteins affect the protrusion speed of the actin network and the rate of nucleation of filaments. We computed a phase diagram showing the regimes of motility enhancement and inhibition by these proteins. Our work shows that the effects of capping and anti-capping proteins are mainly transmitted by modulation of the filamentous network density and local availability of monomeric actin. We discovered that the combination of the capping/anti-capping regulatory network with nucleation-promoting proteins introduces robustness and redundancy in cell motility machinery, allowing the cell to easily achieve maximal protrusion speeds under a broader set of conditions. Finally, we discuss distributions of filament lengths under various conditions and speculate on their potential implication for the emergence of filopodia from the lamellipodial network.

Sistema radicular de plantas de cobertura sob compactação do solo Root system of cover crops under soil compaction

Directory of Open Access Journals (Sweden)

Wainer G. Gonçalves

2006-04-01

Full Text Available Com o objetivo de avaliar a capacidade de crescimento de raízes em camadas de solo compactadas, quatro espécies de plantas de cobertura (amaranto, milheto ADR 500, capim pé-de-galinha e kenaf foram cultivadas em anéis de PVC, com níveis de compactação em subsuperfície (densidade do solo: 1,18; 1,34; 1,51 e 1,60 Mg m-3, sendo o experimento conduzido em casa de vegetação, utilizando-se de um Latossolo Vermelho distroférrico. A camada compactada em subsuperfície foi restritiva ao crescimento de raízes das espécies estudadas, ocasionando a concentração de raízes na camada superficial. O milheto ADR 500 e o amaranto foram as espécies que se destacaram na produção de massa seca da parte aérea e conseguiram desenvolver-se nas camadas compactadas e abaixo delas. O milheto ADR500 apresentou maior densidade de comprimento radicular em todas as camadas. O capim pé-de-galinha e o amaranto tiveram comportamento semelhante quanto à densidade de comprimento radicular. O capim pé-de-galinha e o kenaf apresentaram menor massa seca de raízes em relação às demais espécies. O kenaf apresentou menores valores de massa seca da parte aérea, mas não foi afetado pela presença de camadas compactadas.With the objective of evaluate the root growth capacity in the compacted soil layer, four vegetal species of the cover crops (amaranth, pearl millet ADR500, finger millet and kenaf were cultivated in columns of PVC with increasing levels of subsurface compaction (soil bulk densities: 1.18; 1.34; 1.51 and 1.60 Mg m-3. The experiment was carried out in a greenhouse conditions, using a Dusky Red Latosol. The subsurface compacted layer was restrictive to the roots growth of the studied species, causing the root concentrating to the surface. Pearl millet ADR500 and the amaranth were the species that had detached in the production of dry matter weight and developed itself in the compacted layers and below of them. Pearl of millet ADR500 presented the

Mercury in mushrooms and soil from the Wieluńska Upland in south-central Poland.

Science.gov (United States)

Falandysz, Jerzy; Bielawski, Leszek; Kawano, Masabide; Brzostowski, Andrzej; Chudzyński, Krzysztof

2002-09-01

Concentrations of mercury were determined in the fruiting bodies of 15 species of higher mushrooms and underlying soil substrate collected from Wieluńska Upland in northern part of Sandomierska Valley in south-central Poland in 1995. A total of 197 samples of caps, 197 stalks, 30 whole fruiting bodies and 227 soil (0-10 cm layer) were analyzed. Mean mercury concentrations in soil substrate corresponding to 15 mushroom species were between 28 +/- 17 and 85 +/- 62 ng/g dry matter (total range between 3.0-190 ng/g). The average cap to stalk concentration quotients of Hg were around 2 (range between 1.1 +/- 1.1 and 2.8 +/- 1.4). However, this quotient in Larch bolete (Suillus grevillei) was 4.4 +/- 6.3. Concentrations of Hg varied depending on the mushroom species. Parasol Mushroom (Macrolepiota procera) and Horse mushroom (Agaricus arvensis) contained the greatest mean mercury concentrations both in caps (between 4500 +/- 1700 and 4400 +/- 2400 ng/g dry matter) and stalks (between 2800 +/- 1300 and 3000 +/- 2000 ng/g dry matter). Both the Parasol Mushroom and Horse mushroom were characterised also by a greater potential to bioconcentrate mercury from soils as evidenced by great bioconcentration factors (BCFs), which were between 170 +/- 160 and 130 +/- 120 for caps, and 110 +/- 97 and 89 +/- 92 for stalks. Mercury concentrations in caps and stalks of False death cap (Amanita citrina) increased (p Suillus luteus).

How to find the optimal partner--studies of snurportin 1 interactions with U snRNA 5' TMG-cap analogues containing modified 2-amino group of 7-methylguanosine.

Science.gov (United States)

Piecyk, Karolina; Niedzwiecka, Anna; Ferenc-Mrozek, Aleksandra; Lukaszewicz, Maciej; Darzynkiewicz, Edward; Jankowska-Anyszka, Marzena

2015-08-01

Snurportin 1 is an adaptor protein that mediates the active nuclear import of uridine-rich small nuclear RNAs (U snRNA) by the importin-β receptor pathway. Its cellular activity influences the overall transport yield of small ribonucleoprotein complexes containing N(2),N(2),7-trimethylguanosine (TMG) capped U snRNA. So far little is still known about structural requirements related to molecular recognition of the trimethylguanosine moiety by snurportin in solution. Since these interactions are of a great biomedical importance, we synthesized a series of new 7-methylguanosine cap analogues with extended substituents at the exocyclic 2-amino group to gain a deeper insight into how the TMG-cap is adapted into the snurportin cap-binding pocket. Prepared chemical tools were applied in binding assays using emission spectroscopy. Surprisingly, our results revealed strict selectivity of snurportin towards the TMG-cap structure that relied mainly on its structural stiffness and compactness. Copyright © 2015 Elsevier Ltd. All rights reserved.

47 CFR 54.623 - Cap.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Cap. 54.623 Section 54.623 Telecommunication... Universal Service Support for Health Care Providers § 54.623 Cap. (a) Amount of the annual cap. The annual cap on federal universal service support for health care providers shall be $400 million per funding...

47 CFR 54.507 - Cap.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Cap. 54.507 Section 54.507 Telecommunication... Universal Service Support for Schools and Libraries § 54.507 Cap. (a) Amount of the annual cap. The annual funding cap on federal universal service support for schools and libraries shall be $2.25 billion per...

A subsoil compaction database: its development, structure and content

NARCIS (Netherlands)

Trautner, A.; Akker, van den J.J.H.; Fleige, H.; Arvidsson, J.; Horn, R.

2003-01-01

A database which holds results of field and laboratory experiments on the impact of subsoil compaction on physical and mechanical soil parameters and on crop yields and environmental impact is being developed within the EU-sponsored concerted action (CA) project "Experiences with the impact of

The pharmaceutical vial capping process: Container closure systems, capping equipment, regulatory framework, and seal quality tests.

Science.gov (United States)

Mathaes, Roman; Mahler, Hanns-Christian; Buettiker, Jean-Pierre; Roehl, Holger; Lam, Philippe; Brown, Helen; Luemkemann, Joerg; Adler, Michael; Huwyler, Joerg; Streubel, Alexander; Mohl, Silke

2016-02-01

Parenteral drug products are protected by appropriate primary packaging to protect against environmental factors, including potential microbial contamination during shelf life duration. The most commonly used CCS configuration for parenteral drug products is the glass vial, sealed with a rubber stopper and an aluminum crimp cap. In combination with an adequately designed and controlled aseptic fill/finish processes, a well-designed and characterized capping process is indispensable to ensure product quality and integrity and to minimize rejections during the manufacturing process. In this review, the health authority requirements and expectations related to container closure system quality and container closure integrity are summarized. The pharmaceutical vial, the rubber stopper, and the crimp cap are described. Different capping techniques are critically compared: The most common capping equipment with a rotating capping plate produces the lowest amount of particle. The strength and challenges of methods to control the capping process are discussed. The residual seal force method can characterize the capping process independent of the used capping equipment or CCS. We analyze the root causes of several cosmetic defects associated with the vial capping process. Copyright © 2015 Elsevier B.V. All rights reserved.

Deformation and Fabric in Compacted Clay Soils

Science.gov (United States)

Wensrich, C. M.; Pineda, J.; Luzin, V.; Suwal, L.; Kisi, E. H.; Allameh-Haery, H.

2018-05-01

Hydromechanical anisotropy of clay soils in response to deformation or deposition history is related to the micromechanics of platelike clay particles and their orientations. In this article, we examine the relationship between microstructure, deformation, and moisture content in kaolin clay using a technique based on neutron scattering. This technique allows for the direct characterization of microstructure within representative samples using traditional measures such as orientation density and soil fabric tensor. From this information, evidence for a simple relationship between components of the deviatoric strain tensor and the deviatoric fabric tensor emerge. This relationship may provide a physical basis for future anisotropic constitutive models based on the micromechanics of these materials.

Effects of P-efficient Transgenic Rice OsPT4 on Inorganic Phosphorus Fractions in Red Soil

Directory of Open Access Journals (Sweden)

WEI Lin-lin

2017-08-01

Full Text Available In a rhizobox experiment with phosphorus(P fertilizer application and P-deficiency, planting wild-type rice(Nipp, P-efficient mutant rice(PHO2, P-efficient transgenic rice(OsPT4 were chosen to evaluate effects of phosphorus efficient transgenic rice on inorganic phosphorus in the rhizosphere and non-rhizosphere soil. The obtained results were summarized as follows:(1Significant higer dry weight and P accumulation were observed in OsPT4 and PHO2 than in Nipp, but lower total P and inorganic phosphorus observed in OsPT4 and PHO2 than in Nipp;(2The concentrations of inorganic phosphorus fractions in the rhizosphere and non-rhizosphere soil were sorted as follows:O-P > Fe-P > Al-P > Ca-P, and the order of inorganic phosphorus fractions adapted to three rice materials;(3When added phosphorus fertilizer, the concents of rhizospheric Al-P, Fe-P and non-rhizospheric Ca-P in three rice materials had no significant difference. The concents of rhizospheric soil O-P and Ca-P in OsPT4 and PHO2 were significantly inferior to Nipp, and their concents of non-rhizospheric soil Al-P, Fe-P and O-P were significantly lower than Nipp. When added no phosphorus fertilizer, the concents of rhizospheric Al-P, O-P, Ca-P and non-rhizosphere Al-P, Ca-P in three rice materials had no significant difference, and the concents of rhizosphere Fe-P and non-rhizosphere soil Fe-P, O-P in OsPT4 and PHO2 were significantly lower than Nipp, but rhizosphere Ca-P was significantly higher than Nipp.

Catastrophic antiphospholipid syndrome (CAPS): Descriptive analysis of 500 patients from the International CAPS Registry.

Science.gov (United States)

Rodríguez-Pintó, Ignasi; Moitinho, Marta; Santacreu, Irene; Shoenfeld, Yehuda; Erkan, Doruk; Espinosa, Gerard; Cervera, Ricard

2016-12-01

To analyze the clinical and immunologic manifestations of patients with catastrophic antiphospholipid syndrome (CAPS) from the "CAPS Registry". The demographic, clinical and serological features of 500 patients included in the website-based "CAPS Registry" were analyzed. Frequency distribution and measures of central tendency were used to describe the cohort. Comparison between groups regarding qualitative variables was undertaken by chi-square or Fisher exact test while T-test for independent variables was used to compare groups regarding continuous variables. 500 patients (female: 343 [69%]; mean age 38±17) accounting for 522 episodes of CAPS were included in the analysis. Forty percent of patients had an associated autoimmune disease, mainly systemic lupus erythematosus (SLE) (75%). The majority of CAPS episodes were triggered by a precipitating factor (65%), mostly infections (49%). Clinically, CAPS was characterized by several organ involvement affecting kidneys (73%), lungs (60%), brain (56%), heart (50%), and skin (47%). Lupus anticoagulant, IgG anticardiolipin and IgG anti-β2-glycprotein antibodies were the most often implicated antiphospholipid antibodies (83%, 81% and 78% respectively). Mortality accounted for 37% of episodes of CAPS. Several clinical differences could be observed based on the age of presentation and its association to SLE. Those cases triggered by a malignancy tended to occur in older patients, while CAPS episodes in young patients were associated with an infectious trigger and peripheral vessels involvement. Additionally, CAPS associated with SLE were more likely to have severe cardiac and brain involvement leading to a higher mortality (48%). Although the presentation of CAPS is characterized by multiorgan thrombosis and failure, clinical differences among patients exist based on age and underlying chronic diseases, e.g. malignancy and SLE. Copyright © 2016 Elsevier B.V. All rights reserved.

Soil physical properties affecting soil erosion in tropical soils

International Nuclear Information System (INIS)

Lobo Lujan, D.

2004-01-01

The total vegetated land area of the earth is about 11,500 hectare. Of this, about 12% is in South America. Of this, about 14% is degraded area. Water erosion, chemical degradation, wind erosion, and physical degradation have been reported as main types of degradation. In South America water erosion is a major process for soil degradation. Nevertheless, water erosion can be a consequence of degradation of the soil structure, especially the functional attributes of soil pores to transmit and retain water, and to facilitate root growth. Climate, soil and topographic characteristics determine runoff and erosion potential from agricultural lands. The main factors causing soil erosion can be divided into three groups: Energy factors: rainfall erosivity, runoff volume, wind strength, relief, slope angle, slope length; Protection factors: population density, plant cover, amenity value (pressure for use) and land management; and resistance factors: soil erodibility, infiltration capacity and soil management. The degree of soil erosion in a particular climatic zone, with particular soils, land use and socioeconomic conditions, will always result from a combination of the above mentioned factors. It is not easy to isolate a single factor. However, the soil physical properties that determine the soil erosion process, because the deterioration of soil physical properties is manifested through interrelated problems of surface sealing, crusting, soil compaction, poor drainage, impeded root growth, excessive runoff and accelerated erosion. When an unprotected soil surface is exposed to the direct impact of raindrops it can produce different responses: Production of smaller aggregates, dispersed particles, particles in suspension and translocation and deposition of particles. When this has occurred, the material is reorganized at the location into a surface seal. Aggregate breakdown under rainfall depends on soil strength and a certain threshold kinetic energy is needed to start

Tillage effects on topsoil structural quality assessed using X-ray CT, soil cores and visual soil evaluation

DEFF Research Database (Denmark)

Garbout, Amin; Munkholm, Lars Juhl; Hansen, Søren Baarsgaard

2013-01-01

stratification of the 0–20 cm topsoil layer for both tillage treatments. The stratification of the direct drilled soil was in accordance with our expectations whereas it was surprising for the ploughed soil. The dense lower topsoil layer for the ploughed soil was probably caused by compaction during secondary...

Bioindication with soil microfauna

International Nuclear Information System (INIS)

Aescht, E.; Foissner, W.

1992-01-01

The state of a soil can be characterised through its inhabitant micro-, meso-, and macrofauna. For an appropriate assessment of soil quality at least one representative of each of these size categories should be studied (e.g. testacea, mites, earthworms). This contribution summarizes the insights gained from microscopic soil fauna in this context. The following practical examples are discussed: pesticides, organic and artificial fertilisers, soil compaction, ecological and conventional farming, recolonisation. The 'weighted cenosis index' represents a quantitative measure for the influence of anthropogenic activity on a soil. (orig.) [de

The rebirth of the cervical cap.

Science.gov (United States)

Cappiello, J D; Grainger-Harrison, M

1981-01-01

In an effort to dispel myths surrounding the cervical cap, the historical and political factors affecting the cap's use in the U.S. are described. Clinical aspects of cap fitting are also included. The cervical cap has found only limited acceptance in the U.S. Skepticisms on the part of physicians may be the result of 2 factors: confusion of the cervical cap with intracervical devices used for artificial insemination and confusion with stem pessaries; and the lack of clinical research and statistical evaluation of efficacy rates. The latter factor prompted Tietze et al. to conduct the only U.S. statistical study of the cap in 1953. Of the 143 women studied, the pregnancy rate was 7.6/100 years of use. Of the 28 unplanned pregnancies, 6 were related to faulty technique or omission of a spermicide and 10 were instances of admittedly irregular use. When these failures are omitted, the theoretical effectiveness rate is about 98%. Some practitioners are concerned about an increased incidence of cervical erosion with cap use. Possibly currently conducted studies will show that cap and spermicide users have a lower incidence of cervical erosion than women using no contraceptive method. Study findings suggest that the cervical cap may afford protection without any spermicidal supplement, but the use of spermicides continues to be recommended to clients. Advantages of the cervical cap include the following: it can be left in place longer than a diaphragm without additional applications of spermicide in the vagina; and the insertion of the cap is unrelated to the time of intercourse. Despite research on toleration of the cap for 3 weeks at a time, it is recommended that the cap be worn for only a few days at a time. At this time there are no manufacturers of cervical caps for contraceptive use in the U.S. The cap is now being imported from England and it costs $6.00. A factor that has made the cap unpopular with many physicians is the lengthy time required for fitting. An

Effects of soil management in vineyard on soil physical and chemical characteristics

Directory of Open Access Journals (Sweden)

Linares Rubén

2014-01-01

Full Text Available Cover crops in Mediterranean vineyards are scarcely used due to water competition between the cover crop and the grapevine; however, bare soil management through tillage or herbicides tends to have negative effects on the soil over time (organic matter decrease, soil structure and soil fertility degradation, compaction, etc. The objective of this study was to understand how soil management affects soil fertility, compaction and infiltration over time. To this end, two bare soil techniques were compared, tillage (TT and total herbicide (HT with two cover crops; annual cereal (CT and annual grass (AGT, established for 8 years. CT treatment showed the highest organic matter content, having the biggest amount of biomass incorporated into the soil. The annual adventitious vegetation in TT treatment (568 kg dry matter ha-1 that was incorporated into the soil, kept the organic matter content higher than HT levels and close to AGT level, in spite of the greater aboveground annual biomass production of this treatment (3632 kg dry matter ha-1 whereas only its roots were incorporated into the soil. TT presented the highest bulk density under the tractor track lines and a greatest resistance to penetration (at 0.2 m depth. AGT presented bulk density values (upper 0.4 m lower than TT and penetration resistance in CT lower (at 0.20 m depth than TT too. The HT decreased water infiltration due to a superficial crust generated for this treatment. These results indicate that the use of annual grass cover can be a good choice of soil management in Mediterranean climate due to soil quality improvement, with low competition and simple management.

Influence of nano-material on the expansive and shrinkage soil behavior

International Nuclear Information System (INIS)

Taha, Mohd Raihan; Taha, Omer Muhie Eldeen

2012-01-01

This paper presents an experimental study performed on four types of soils mixed with three types of nano-material of different percentages. The expansion and shrinkage tests were conducted to investigate the effect of three type of nano-materials (nano-clay, nano-alumina, and nano-copper) additive on repressing strains in compacted residual soil mixed with different ratios of bentonite (S1 = 0 % bentonite, S2 = 5 % bentonite, S3 = 10 % bentonite, and S4 = 20 % bentonite). The soil specimens were compacted under the condition of maximum dry unit weight and optimum water content (w opt ) using standard compaction test. The physical and mechanical results of the treated samples were determined. The untreated soil values were used as control points for comparison purposes. It was found that with the addition of optimum percentage of nano-material, both the swell strain and shrinkage strain reduced. The results show that nano-material decreases the development of desiccation cracks on the surface of compacted samples without decrease in the hydraulic conductivity.

Seasonal dynamics in wheel load-carrying capacity of a loam soil in the Swiss Plateau

DEFF Research Database (Denmark)

Gut, S.; Chervet, A.; Stettler, Matthias

2015-01-01

on in situ measurements of h, measurements of precompression stress at various h and simulations of soil stress. In this work, we concentrated on prevention of subsoil compaction. Calculations were made for different tyres (standard and low-pressure top tyres) and for soil under different tillage......Subsoil compaction is a major problem in modern agriculture caused by the intensification of agricultural production and the increase in weight of agricultural machinery. Compaction in the subsoil is highly persistent and leads to deterioration of soil functions. Wheel load-carrying capacity (WLCC......) is defined as the maximum wheel load for a specific tyre and inflation pressure that does not result in soil stress in excess of soil strength. The soil strength and hence WLCC is strongly influenced by soil matric potential (h). The aim of this study was to estimate the seasonal dynamics in WLCC based...

Chemically stabilized soils.

Science.gov (United States)

2009-12-01

The objective of this study was to conduct laboratory evaluations to quantify the effects of compaction and moisture conditions on the strength of chemically treated soils typical utilized in pavement construction in Mississippi.

Tricalcium phosphate powder: Preparation, characterization and compaction abilities

Directory of Open Access Journals (Sweden)

Abida Fatima

2017-02-01

Full Text Available In this work, we characterize tricalcium phosphate powders Ca9(HPO4(PO45(OH resulting from a reaction between calcium hydroxide and orthophosphoric acid at room temperature, without pH adjustment and in absence of ionic impurities. The prepared powder has an atomic ratio Ca/P of 1.512 ± 0.005. The real density is 2.68 ± 0.02 g/cm3 and the specific surface area is 80 ± 02 m2/g. During compression, the microstructure of Ca-deficient apatite powder with the presence of HPO4 groups seems to support the cohesion between particles. The transmission ratio is 90%, the transfer ratio is 41.8 and the ratio of the die-wall friction is 0.22. These results show that apatitic tricalcium powder gives a good aptitude to the compaction which leads to a good tensile strength (0.79 MPa. The heat treatment of the prepared powder shows the precise temperature for the formation of pyrophosphate, β-TCP and α-TCPa phases.  The purity and aptitude to compaction of the prepared powders are very promising for pharmaceutical and medical applications.

Microtubule's conformational cap

DEFF Research Database (Denmark)

Flyvbjerg, H.

1999-01-01

The molecular mechanisms that allow elongation of the unstable microtubule lattice remain unclear. It is usually thought that the GDP-liganded tubulin lattice is capped by a small layer of GTP- or GDP-P(i)-liganded molecules, the so called "GTP-cap". Here, we point-out that the elastic properties...

Permeability response of oil-contaminated compacted clays

International Nuclear Information System (INIS)

Silvestri, V.; Mikhail, N.; Soulie, M.

1997-01-01

This paper presents the results of a laboratory investigation on the behavior of motor oil-contaminated, partially saturated compacted clays. For the study, both a natural clay and an artificially purified kaolinite, contaminated with 0 to 8% of motor oil, were firstly compacted following the ASTM standard procedure. Secondly, permeability tests were carried out in a triaxial cell on 10 cm-diameter compacted clay specimens. The results of the investigation indicate that increasing percentages of motor oil decrease both the optimum water content and the optimum dry density of the two clays. However, whereas the optimum water content on the average decreases by about 6% when the percentage contamination increases from 0 to 8%, the corresponding decrease in the optimum dry density is less than 3%. Even though the optimum dry density decreases as the percentage of oil increases from 0 to 8%, there is, however, a range in oil content varying between 2 and 4% for which the optimum dry density is slightly greater than that of the untreated soils. As far as the permeability tests are concerned, the results indicate that as the percentage of oil increases, the coefficient of permeability decreases substantially, especially for clay specimens which were initially compacted on the dry side of optimum

Chemical Modification of Uniform Soils and Soils with High/Low Plasticity Index

OpenAIRE

Li, Xuanchi; Tao, Fei; Bobet, Antonio

2015-01-01

Lime and/or cement are used to treat weak subgrade soils during construction of highways. These chemicals are mixed with the soil to improve its workability, compactability and engineering properties. INDOT (Indiana Department of Transportation) has been using chemical modification of native soils for the past 20 years. In fact, 90% of current subgrade is treated, typically with quick lime, lime byproducts or cement. For pavement design, it is customary to not include any improvement of the s...

75 FR 49527 - Caps Visual Communications, LLC; Black Dot Group; Formerly Known as Caps Group Acquisition, LLC...

Science.gov (United States)

2010-08-13

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-74,195] Caps Visual Communications, LLC; Black Dot Group; Formerly Known as Caps Group Acquisition, LLC Chicago, IL; Amended... of Caps Visual Communications, LLC, Black Dot Group, formerly known as Caps Group Acquisition, LLC...

Macrophage Capping Protein CapG Is a Putative Oncogene Involved in Migration and Invasiveness in Ovarian Carcinoma

Directory of Open Access Journals (Sweden)

J. Glaser

2014-01-01

Full Text Available The actin binding protein CapG modulates cell motility by interacting with the cytoskeleton. CapG is associated with tumor progression in different nongynecologic tumor entities and overexpression in breast cancer cell lines correlates with a more invasive phenotype in vitro. Here, we report a significant CapG overexpression in 18/47 (38% of ovarian carcinomas (OC analyzed by qRealTime-PCR analyses. Functional analyses in OC cell lines through siRNA mediated CapG knockdown and CapG overexpression showed CapG-dependent cell migration and invasiveness. A single nucleotide polymorphism rs6886 inside the CapG gene was identified, affecting a CapG phosphorylation site and thus potentially modifying CapG function. The minor allele frequency (MAF of SNP rs6886 (c.1004A/G was higher and the homozygous (A/A, His335 genotype was significantly more prevalent in patients with fallopian tube carcinomas (50% as in controls (10%. With OC being one of the most lethal cancer diseases, the detection of novel biomarkers such as CapG could reveal new diagnostic and therapeutic targets. Moreover, in-depth analyses of SNP rs6886 related to FTC and OC will contribute to a better understanding of carcinogenesis and progression of OC.

[Effects of heavy machinery operation on the structural characters of cultivated soils in black soil region of Northeast China].

Science.gov (United States)

Wang, En-Heng; Chai, Ya-Fan; Chen, Xiang-Wei

2008-02-01

With the cultivated soils in black soil region of Northeast China as test objects, this paper measured their structural characters such as soil strength, bulk density, and non-capillary porosity/capillary porosity (NCP/CP) ratio before and after heavy and medium-sized machinery operation, aimed to study the effects of machinery operation on the physical properties of test soils. The results showed that after machinery operation, there existed three distinct layers from top to bottom in the soil profiles, i.e., plowed layer, cumulative compacted layer, and non-affected layer, according to the changes of soil strength. Under medium-sized machinery operation, these three layers were shallower, and there was a new plow pan at the depth between 17.5 and 30 cm. Heavy machinery operation had significant positive effects on the improvement of topsoil structure (P heavy machinery, the bulk density of topsoil decreased by 7.2% and 3.5%, respectively, and NCP/CP increased by 556.6% after subsoiling, which would benefit water infiltration, reinforce water storage, and weaken the threat of soil erosion. The main action of heavy machinery operation was soil loosening, while that of medium-sized machinery operation was soil compacting.

Temporary effect of chiseling on the compaction of a Rhodic Hapludox under no-tillage

Directory of Open Access Journals (Sweden)

Sâmala Glícia Carneiro Silva

2012-04-01

Full Text Available Mechanical chiseling has been used to alleviate the effects of compaction in soils under no-tillage (NT. However, its effect on the soil physical properties does not seem to have a defined duration period. The purpose of this study was to evaluate the behavior of the bulk density (BD and degree of compaction (DC at different soil depths, after chiseling in no-tillage, for one year. The experiment was performed in Ponta Grossa, Paraná State, Brazil, using an Oxisol (Rhodic Hapludox. Bulk density and DC were previously measured in an area under NT for 16 years, then immediately after chiseling (CHI in May 2009, six months after chiseling (CHI6M in October 2009 and one year after chiseling (CHI12M in May 2010. In the layers 0.0-0.10, 0.10-0.20 and 0.20-0.30 m, there was a significant BD reduction CHI and a marked increase CHI6M. The BD values measured CHI12M were similar to those before tillage. Chiseling reduced the DC in the layers 0.0-0.10 m and 0.10-0.20 m, but returned to the initial values one year later. During the evaluation periods CHI, CHI6M and CHI12M, the BD increased in the layer 0.30-0.40 m, compared with NT. The highest DC values were observed six months after chiseling; nevertheless the structural recovery of the soil was considerable, possibly due to the high degree of soil resilience and the influence of the wetting and drying cycles detected in the study period. The chiseling effects, evaluated by BD and DC, lasted less than one year, i.e., the beneficial short-term effects of chiseling on the reduction of the surface BD increased the risk of compaction in deeper soil layers.

Evaluation of Changes in Index Properties of Lateritic Soil Stabilized with Fly Ash

Directory of Open Access Journals (Sweden)

Agapitus AMADI

2010-12-01

Full Text Available For soils to be suitable in civil engineering projects, they must meet existing local requirements for index properties in addition to certain strength criteria. Typically, specifications limit these properties to some threshold values which in most cases are project specific. Some lateritic soils in their natural state need some treatment/modification to meet these specification requirements. The objective of this study was to evaluate changes in the index properties (i.e., particle size distribution, Atterberg limits and compaction characteristics of a residually derived lateritic soil following fly ash application. Lateritic soil – fly ash mixtures with up to 20% fly ash by dry weight of soil were tested and specimens for compaction characteristics were prepared at different compaction states (optimum, dry and wet of optimum moisture content and compacted using British Standard Light (BSL compactive effort. While soil – fly ash mixtures containing up to 15% fly ash classify as CL according to USCS classification system and plotted above A-line in the plasticity chart, it was observed that changes in the gradation characteristics of soil sample treated with 20% fly ash resulted in the alteration of its classification to ML as well as the crossing of the A- line to the silty region. The liquid limit (LL varied from 42.2 to 29.53% representing 70% reduction while the plasticity index (PI of specimen treated with 20% fly ash was 16% lower than that of natural soil. The optimum moisture content (OMC ranged from 17.36% for the natural soil to 18.34% for soil mixtures containing 20% fly ash which yielded dry unit weight of 17.2kN/m3 for the natural soil and 16.1kN/m3 for samples treated with 20% fly ash. From the study, useful data were obtained showing substantial and desirable changes in the properties of lateritic soil as a civil engineering material on application of fly ash.

Eddy intrusion of hot plasma into the polar cap and formation of polar-cap arcs

International Nuclear Information System (INIS)

Chiu, Y.T.; Gorney, D.J.

1983-01-01

We present plasma and electric field data obtained by the S3-3 satellite over the polar caps. We demonstrate that: (1) plasma signatures in the polar cap arc formation region near 5000 km altitude show clear intrusions of plasma sheet (approx.keV) and magneto sheath (approx.100 eV) plasma into a background of low-energy polar cap plasma; (2) the combined plasma and electric field signatures (electron inverted-V, ion beam and delxE<0) are exactly the same as in the evening discrete arc. We interpret this equivalence of polar cap and evening discrete arc signatures as indication that their formation processes are identical. The spatial structures of polar cap electric fields and the associated plasma signatures are consistent with the hypothesis that plasma intrusion into the polar cap takes the form of multiple cellular eddies. This hypothesis provides a unifying view of arc formation and arc configurations

North Polar Cap

Science.gov (United States)

2004-01-01

[figure removed for brevity, see original site] This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour. In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime. The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap. Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen

Measurement of the open porosity of agricultural soils with acoustic waves

Science.gov (United States)

Luong, Jeanne; Mercatoris, Benoit; Destain, Marie-France

2015-04-01

The space between agricultural soil aggregates is defined as structural porosity. It plays important roles in soil key functions that an agricultural soil performs in the global ecosystem. Porosity is one of the soil properties that affect plant growth along with soil texture, aggregate size, aeration and water holding capacity (Alaoui et al. 2011). Water supplies regulation of agricultural soil is related to the number of very small pores present in a soil due to the effect of capillarity. Change of porosity also affect the evaporation of the water on the surface (Le Maitre et al. 2014). Furthermore, soil is a habitat for soils organisms, and most living organisms, including plant roots and microorganisms require oxygen. These organisms breathe easier in a less compacted soil with a wide range of pores sizes. Soil compaction by agricultural engine degrades soil porosity. At the same time, fragmentation with tillage tools, creation of cracks due to wetting/drying and freezing/thawing cycles and effects of soil fauna can regenerate soil porosity. Soil compaction increases bulk density since soil grains are rearranged decreasing void space and bringing them into closer contact (Hamza & Anderson 2005). Drainage is reduced, erosion is facilitated and crop production decreases in a compacted soil. Determining soil porosity, giving insight on the soil compaction, with the aim to provide advices to farmers in their soil optimization towards crop production, is thus an important challenge. Acoustic wave velocity has been correlated to the porosity and the acoustic attenuation to the water content (Oelze et al. 2002). Recent studies have shown some correlations between the velocity of acoustic waves, the porosity and the stress state of soil samples (Lu et al. 2004; Lu 2005; Lu & Sabatier 2009), concluding that the ultrasonic waves are a promising tool for the rapid characterisation of unsaturated porous soils. Propagation wave velocity tends to decrease in a high porous

Effect of Particle Size and Soil Compaction on Gas Transport Parameters in Variably Saturated, Sandy Soils

DEFF Research Database (Denmark)

Hamamoto, Shoichiro; Møldrup, Per; Kawamoto, Ken

2009-01-01

The soil gas diffusion coefficient (Dp) and air permeability (ka) and their dependency on soil air content ( ) control gas diffusion and advection in soils. This study investigated the effects of average particle size (D50) and dry bulk density ( b) on Dp and ka for six sandy soils under variably...

Fertilizer shanks to promote soil decompaction in the seeding operation

Directory of Open Access Journals (Sweden)

Marta Sandra Drescher

Full Text Available ABSTRACT: Intensification of soil compaction process under no-tillage (NT is motivating the search for alternatives to mitigate soil compaction state. This study evaluated changes in soil physical and hydraulic properties caused by seeder with fertilizer shanks at different depths compared with the double discs lagged seeder, to investigate the possibility of soil decompaction by sowing under NT in southern Brazil. The study was conducted in a clayed Oxisol, for 27 years under NT. Treatments were three planting mechanisms: S0.10m: cutting disc combined with shank acting to 0.10m depth; S0.15m: cutting disc combined with shank acting to 0.15m depth and, D0.07m: double discs lagged acting to 0.07m depth in an experimental randomized block design with four replications. We evaluated the soil mechanical resistance, water infiltration rate, soil bulk density, pore size distribution and unsaturated hydraulic conductivity. Results indicated that the use of seeder with fertilizer shanks acting at 0.15m deep promoted the soil decompaction by the reduction of penetration resistance and increase of porosity and unsaturated hydraulic conductivity. To have significant increase in water infiltration rate the fertilizer shanks of the seeder must be deepened to the lower limit of the compacted surface layer.

The effect of an engineered closure cap on radon gas transport from a shallow land burial site

International Nuclear Information System (INIS)

Lindstrom, F.T.; Cawlfield, D.E.; Donahue, M.E.; Emer, D.F.; Shott, G.J.

1992-01-01

US Department of Energy (DOE) Order 5820.2A requires performance assessment of all new and existing low level radioactive waste disposal sites. An integral part of performance assessment is estimating the fluxes of radioactive gases such as radon-220 and radon-222. Mathematical models, which in themselves point out data needs and therefore drive site characterization, provide a logical means of performing the required flux estimations. The effects of an engineered closure cap on radon gas transport in a very dry alluvial soil in the southwestern desert are considered in detail in this paper. Our model (Lindstrom, et al. 1992 a ampersand b and Cawlfield et al. 1992 a ampersand b) was constructed in a site specific fashion because the existing mathematical models of noble gas transport from the spatial point of origin in the low level waste repository through the surrounding soil and closure cap with subsequent release to the atmosphere are few in numbers (Nazaroff, 1992)

Designing Smart Charter School Caps

Science.gov (United States)

Dillon, Erin

2010-01-01

In 2007, Andrew J. Rotherham proposed a new approach to the contentious issue of charter school caps, the statutory limits on charter school growth in place in several states. Rotherham's proposal, termed "smart charter school caps," called for quality sensitive caps that allow the expansion of high-performing charter schools while also…

Characterizing soil erosion potential using electrical resistivity imaging : final report.

Science.gov (United States)

2017-04-01

The erosion rate, or erodibility, of soil depends on many soil characteristics including: plasticity, : water content, grain size, percent clay, compaction, and shear strength. Many of these characteristics also : influence soil in situ bulk electric...

Characterizing soil erosion potential using electrical resistivity imaging : technical summary.

Science.gov (United States)

2017-04-01

The erosion rate, or erodibility, of soil depends on many soil characteristics : including: plasticity, water content, grain size, percent clay, compaction, and shear : strength. Many of these characteristics also influence soil in situ bulk electric...

compaction and consolidation characteristics of lateritic soil

African Journals Online (AJOL)

user

SOIL OF A SELECTED SITE IN IKOLE EKITI, SOUTHWEST NIGERIA. A. Bolarinwa1,*, J. B. ... various locally available materials for stabilization/ improvement of some .... attempted but futile as some of the clays were too sandy to stay in the ...

Precise soil management as a tool to reduce CH4 and N2O emissions from agricultural soils

NARCIS (Netherlands)

Mosquera Losada, J.; Hol, J.M.G.; Rappoldt, C.; Dolfing, J.

2007-01-01

Soil compaction stimulates the emission of nitrous oxide (N2O) and methane (CH4) from agricultural soils. N2O and CH4 are potent greenhouse gases, with a global warming potential respectively 296 times and 23 times greater than CO2.. Agricultural soils are an important source of N2O. Hence there is

NATURE MANAGEMENT, LANDSCAPE AND THE CAP

OpenAIRE

Brouwer, Floor M.; Godeschalk, Frans E.

2004-01-01

The integration of nature management, landscape and environmental concerns into the Common Agricultural Policy (CAP) has gained momentum with the CAP reforms adopted in June 2003. The report explores instruments and approaches that contribute to the inte-gration of nature conservation and landscape concerns into the CAP. A broader use of the CAP instruments might help to achieve nature types in the Netherlands.

Indicadores hídrico-mecânicos de compactação do solo e crescimento de plantas Hydric and mechanical indicators of soil compaction and plant growth

Directory of Open Access Journals (Sweden)

Paulo Ivonir Gubiani

2013-02-01

Full Text Available O efeito da compactação do solo sobre o crescimento de plantas é uma informação necessária para orientar o manejo do solo. Embora o intervalo hídrico ótimo (IHO tenha sistematizado a relação entre compactação e fatores físicos diretamente relacionados com o crescimento de plantas, sua eficiência para prever respostas biológicas, sobretudo a produção de grãos, ainda não foi comprovada. Resultados de pesquisas em nível celular indicam que os níveis de estresses hídricos e mecânicos que ocorrem nas raízes durante o secamento do solo são parcialmente representados pelo IHO. Consequentemente, a previsão de resposta no crescimento e na produção das culturas não se confirma na maioria dos casos. Além do refinamento dos limites do IHO, novos índices precisam ser desenvolvidos, com capacidade de integrar a variação dos fatores físicos do solo ao longo do ciclo de crescimento das plantas, determinados por fatores meteorológicos. Indicadores de frequência, período de ausência e acumulado de estresses hídricos mecânicos foram sugeridos. Sem avanços, a capacidade de previsão do risco de redução na produção das culturas por compactação do solo será pequena e insuficiente para orientar ações de manejo do solo.The effect of soil compaction on plant growth is widely used as orientation for soil management. Although the limiting water range (LLWR underlies the systematization of the relationship between compaction and physical factors directly related to plant growth, its efficiency to predict biological responses, especially of grain yield, has not yet been proven. Results of research at the cellular level indicate that the water and mechanical stress levels that occur in the roots during soil drying are partially represented by the LLWR. Consequently, the expected response in crop growth and production cannot be achieved in most cases. In addition to refining the boundaries of the LLWR, new indexes need to be

CAPS Simulation Environment Development

Science.gov (United States)

Murphy, Douglas G.; Hoffman, James A.

2005-01-01

The final design for an effective Comet/Asteroid Protection System (CAPS) will likely come after a number of competing designs have been simulated and evaluated. Because of the large number of design parameters involved in a system capable of detecting an object, accurately determining its orbit, and diverting the impact threat, a comprehensive simulation environment will be an extremely valuable tool for the CAPS designers. A successful simulation/design tool will aid the user in identifying the critical parameters in the system and eventually allow for automatic optimization of the design once the relationships of the key parameters are understood. A CAPS configuration will consist of space-based detectors whose purpose is to scan the celestial sphere in search of objects likely to make a close approach to Earth and to determine with the greatest possible accuracy the orbits of those objects. Other components of a CAPS configuration may include systems for modifying the orbits of approaching objects, either for the purpose of preventing a collision or for positioning the object into an orbit where it can be studied or used as a mineral resource. The Synergistic Engineering Environment (SEE) is a space-systems design, evaluation, and visualization software tool being leveraged to simulate these aspects of the CAPS study. The long-term goal of the SEE is to provide capabilities to allow the user to build and compare various CAPS designs by running end-to-end simulations that encompass the scanning phase, the orbit determination phase, and the orbit modification phase of a given scenario. Herein, a brief description of the expected simulation phases is provided, the current status and available features of the SEE software system is reported, and examples are shown of how the system is used to build and evaluate a CAPS detection design. Conclusions and the roadmap for future development of the SEE are also presented.

Performance Enhancement of the RatCAP Awake Rate Brain PET System

Energy Technology Data Exchange (ETDEWEB)

Vaska, P.; Vaska, P.; Woody, C.; Schlyer, D.; Radeka, V.; O' Connor, P.; Park, S.-J.; Pratte, J.-F.; Junnarkar, M.; Purschke, S.; Southekal, S.; Stoll, S.; Schiffer, W.; Neill, J.; Wharton, D.; Myers, N.; Wiley, S.; Kandasamy, A.; Fried, J.; Krishnamoorthy, S. Kriplani, A.; Maramraju, S.; Lecomte, R.; Fontaine, R.

2011-03-01

The first full prototype of the RatCAP PET system, designed to image the brain of a rat while conscious, has been completed. Initial results demonstrated excellent spatial resolution, 1.8 mm FWHM with filtered backprojection and <1.5 mm FWHM with a Monte Carlo based MLEM method. However, noise equivalent countrate studies indicated the need for better timing to mitigate the effect of randoms. Thus, the front-end ASIC has been redesigned to minimize time walk, an accurate coincidence time alignment method has been implemented, and a variance reduction technique for the randoms is being developed. To maximize the quantitative capabilities required for neuroscience, corrections are being implemented and validated for positron range and photon noncollinearity, scatter (including outside the field of view), attenuation, randoms, and detector efficiency (deadtime is negligible). In addition, a more robust and compact PCI-based optical data acquisition system has been built to replace the original VME-based system while retaining the linux-based data processing and image reconstruction codes. Finally, a number of new animal imaging experiments have been carried out to demonstrate the performance of the RatCAP in real imaging situations, including an F-18 fluoride bone scan, a C-11 raclopride scan, and a dynamic C-11 methamphetamine scan.

Performance Enhancement of the RatCAP Awake Rat Brain PET System

International Nuclear Information System (INIS)

Vaska, P.; Woody, C.; Schlyer, D.; Radeka, V.; O'Connor, P.; Park, S.-J.; Pratte, J.-F.; Junnarkar, S.; Purschke, M.; Southekal, S.; Stoll, S.; Schiffer, W.; Lee, D.; Neill, J.; Wharton, D.; Myers, N.; Wiley, S.; Kandasamy, A.; Fried, J.; Krishnamoorthy, S.; Kriplani, A.; Maramraju, S.; Lecomte, R.; Fontaine, R.

2011-01-01

The first full prototype of the RatCAP PET system, designed to image the brain of a rat while conscious, has been completed. Initial results demonstrated excellent spatial resolution, 1.8 mm FWHM with filtered backprojection and <1.5 mm FWHM with a Monte Carlo based MLEM method. However, noise equivalent countrate studies indicated the need for better timing to mitigate the effect of randoms. Thus, the front-end ASIC has been redesigned to minimize time walk, an accurate coincidence time alignment method has been implemented, and a variance reduction technique for the randoms is being developed. To maximize the quantitative capabilities required for neuroscience, corrections are being implemented and validated for positron range and photon noncollinearity, scatter (including outside the field of view), attenuation, randoms, and detector efficiency (deadtime is negligible). In addition, a more robust and compact PCI-based optical data acquisition system has been built to replace the original VME-based system while retaining the linux-based data processing and image reconstruction codes. Finally, a number of new animal imaging experiments have been carried out to demonstrate the performance of the RatCAP in real imaging situations, including an F-18 fluoride bone scan, a C-11 raclopride scan, and a dynamic C-11 methamphetamine scan.

The cervical cap (image)

Science.gov (United States)

The cervical cap is a flexible rubber cup-like device that is filled with spermicide and self-inserted over the cervix ... left in place several hours after intercourse. The cap is a prescribed device fitted by a health ...

Does uncertainty justify intensity emission caps?

International Nuclear Information System (INIS)

Quirion, Philippe

2005-01-01

Environmental policies often set 'relative' or 'intensity' emission caps, i.e. emission limits proportional to the polluting firm's output. One of the arguments put forth in favour of relative caps is based on the uncertainty on business-as-usual output: if the firm's production level is higher than expected, so will be business-as-usual emissions, hence reaching a given level of emissions will be more costly than expected. As a consequence, it is argued, a higher emission level should be allowed if the production level is more important than expected. We assess this argument with a stochastic analytical model featuring two random variables: the business-as-usual emission level, proportional to output, and the slope of the marginal abatement cost curve. We compare the relative cap to an absolute cap and to a price instrument, in terms of welfare impact. It turns out that in most plausible cases, either a price instrument or an absolute cap yields a higher expected welfare than a relative cap. Quantitatively, the difference in expected welfare is typically very small between the absolute and the relative cap but may be significant between the relative cap and the price instrument. (author)

Modifications to an existing waste containment structure at Niagara Falls Storage Site

International Nuclear Information System (INIS)

Paez-Restrepo, A.; Darby, J.W.

1992-01-01

The Niagara Falls Storage Site (NFSS), located near Lewiston, New York, is an interim waste containment facility for low-level radioactive waste. The facility was completed in 1986 and is managed for the Department of Energy (DOE) by Bechtel National, Inc. (BNI) as part of the Formerly Utilized Sites Remedial Action Program (FUSRAP). The waste containment structure (WCS) at NFSS is approximately 297 m (975 ft) long and 137 m (450 ft) wide and reaches a maximum height of 10.4 m (34 ft). The peripheral slopes rise at an angle of 3:1 (h:v) for a width of about 16.8 m (55 ft), where the inclination decreases to 7.5%. The apex of the pile is higher at the south end, sloping about 1.2 m (4 ft) to the north. The interim layered cap consists of 0.9 m (3 ft) of clay overlain by 0.45 m (1.5 ft) of topsoil. The uppermost 15 cm (6 in.) of soil was loosely compacted to permit the development of a grass cover. In the summer of 1991, approximately 2,677 m 3 (3,500 yd 3 ) of additional contaminated soil and material in temporary storage elsewhere at NFSS was incorporated into the WCS. To accommodate the waste, a portion of the cap roughly centered with the pile [including 0.45 m (1.5 ft) of topsoil and 0.6 m (2 ft) of clay cap] was removed from an area 99 m (325 ft) long and 58.5 m (192 ft) wide, leaving a minimum of 0.3 m (I ft) of clay over the old waste as a radiation and radon barrier. The newly incorporated waste forms a layer 0.6 m (2 ft) thick, replacing the clay portion of the excavated cap. The waste is contained laterally by the old cap and sealed by a new cap, which also consists of 0.9 m (3 ft) of compacted clay and 0.45 m (1.5 ft) of topsoil. A transition zone about 6.1 m (20 ft) wide feathers the new cap to the old cap (see Fig. 3). Except for the uppermost 10.5 to 15.2 cm (4 to 6 in.) of vegetated topsoil, the excavated cap materials were stockpiled and reused in constructing the new cap. Additional material required to complete cap construction was imported from

Cryopyrin-Associated Autoinflammatory Syndromes (CAPS) - Juvenile

Science.gov (United States)

... all ethnic groups can be affected. What are CAPS? Cryopyrin-associated autoinflammatory syndromes (CAPS) consist of three ... ears by magnetic resonance imaging (MRI). How is CAPS treated? Medications that target interleukin-1 are very ...

Finite Element Method Study on Stress State in Soil Induced by Agricultural Traffic

Directory of Open Access Journals (Sweden)

Adrian Molnar-Irimie

2016-11-01

Full Text Available In general, when a tyre is running on a deformable soil, the soil compaction will occur not only on surface layers, but also on soil profile, in deeper layers. This leads to a series of negative effects not only on physical and mechanical properties of soil, but also influences the crops growth and the crop yield. For these reasons, currently are needed solutions to reduce soil compaction, caused mainly by agricultural implements passing on the soil surface in order to aply the specific crop production technologies. From our simulation we can draw the following conclusions: the soil stresses decreased with depth; the soil displacements magnitude increased with soil water content due to lower friction forces between soil particles (water acts like a lubricant between soil particles; decreasing rate for soil displacement is influenced by load magnitude and tyre inflation pressure; the soil particles moved in vertical plain from the top to the bottom, but also in horizontal direction, from the center to the edge in cross section and in longitudinal direction; the dimensions of the geometric shape of the mentioned soil volume is influenced by load and tyre inflation pressure. In this paper the agricultural traffic and its influence on stress state in soil, it was used a software application based on Finite Element Method, that has been proved to be a useful tool for soil compaction assessment in order to find the right decisions for a proper field traffic management.

Effect of soil erosion on the long-term stability of FUSRAP near-surface waste-burial sites

International Nuclear Information System (INIS)

Knight, M.J.

1983-04-01

Decontamination of FUSRAP sites could result in the generation of large volumes (in excess of 400,000 m 3 ) of low-activity radioactive wastes (primarily contaminated soil and building materials) requiring subsequent disposal. It is likely that near-surface burial will be seriously considered as an option for disposal of these materials. A number of factors - including soil erosion - could adversely affect the long-term stability of a near-surface waste-burial site. The majority of FUSRAP sites are located in the humid eastern United States, where the principal cause of erosion is the action of water. This report examines the effect of soil erosion by water on burial-site stability based on analysis of four hypothetical near-surface burial sites. The Universal Soil Loss Equation was employed to estimate average annual soil loss from burial sites and the 1000-year effects of soil loss on the soil barrier (burial trench cap) placed over low-activity wastes. Results suggest that the land use of the burial site and the slope gradient of the burial trench cap significantly affect the rate of soil erosion. The development of measures limiting the potential land use of a burial site (e.g., mixing large rocks into the burial trench cap) may be required to preserve the integrity of a burial trench for long periods of time

The North Zealand CAP Monitor

DEFF Research Database (Denmark)

Nielsen, Minna; Ravn, Pernille; Notander Clausen, Lise

with CAP. We started with 34 audit variables. Through repeated cycles of testing, feedback and discussions, we reduced the number of indicators to 22 and time per audit from 20 to 10 minutes. Strategy for change To link the monitoring system with our patient pathway for CAP we established an improvement...... Designing a database Designing and testing a dashboard to present indicators in a balanced way Messages for others Auditing patients with a common disease as CAP is useful to identify areas for improvement for a large group of patients. The baseline audit can serve as a basis for a monitoring system......Contect We describe how we developed a monitoring system for community acquired pneumonia (CAP) at North Zealand Regional hospital. We serve 310.000 inhabitants and annually around 3200 patients with CAP are admitted. As part of a program of clinical pathways for common conditions, a pathway...

Harvest traffic monitoring and soil physical response in a pine plantation

Science.gov (United States)

Emily A. Carter; Timothy P. McDonald; John L. Torbert

2000-01-01

Mechanized forest harvest operations induce changes in soil physical properties, which have the potential to impact soil sustainability and forest productivity. The assessment of soil compaction and its spatial variability has been determined previously through the identification and tabulation of visual soil disturbance classes and soil physical changes associated...

Importance of Soil Quality in Environment Protection

OpenAIRE

Márta Birkás; Tibor Kalmár; László Bottlik; Tamás Takács

2007-01-01

Soil quality can be characterised by the harmony between it’s physical and biological state and the fertility. From the practical crop production viewpoint, some important contrasting factors of soil quality are: (1) soil looseness – compaction; (2) aggregation – clod and dust formation; friable structure – smeared or cracked structure; (3) organic material: conservation – decrease; (4) soil moisture: conservation – loss; water transmission – water-logging; (5) at least soil condition as a re...

Ponderosa pine growth response to soil strength in the volcanic ash soils of central Oregon.

Science.gov (United States)

R.T. Parker; D.A. Maguire; D.D. Marshall; P. Cochran

2007-01-01

Mechanical harvesting and associated logging activities have the capacity to compact soil across large portions of harvest units. Two thinning treatments (felled only versus felled and skidded) in 70- to 80-year-old ponderosa pine stands were replicated at three sites with volcanic soils in central Oregon. Growth in diameter, height, and volume of residual trees were...

Analysis of laboratory compaction methods of roller compacted concrete

Science.gov (United States)

Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

2017-09-01

Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

Estimated release from the saltstone landfill effect of landfill caps and landfill-cap/monolith-liner combinations

International Nuclear Information System (INIS)

Wilhite, E.L.

1985-01-01

The effect of capping the entire saltstone landfill is dependent on the effectiveness of the clay cap in preventing infiltration. A cap that is 99% effective will reduce releases from the saltstone landfill by a factor of 7.7. Several combinations of landfill design alterations will result in meeting ground water standards

Effect of soil compaction and biomass removal on soil CO2 efflux in a Missouri forest

Science.gov (United States)

Felix, Jr. Ponder

2005-01-01

Forest disturbances associated with harvesting activities can affect soil properties and soil respiration. A soda-lime technique was used to measure soil carbon dioxide (CO2) efflux rates in clearcut plots of a Missouri oak-hickory (Quercus spp. L.-Carya spp. Nutt.) forest 4 years after being treated with two levels of forest...

Mercury in wild mushrooms and underlying soil substrate from Koszalin, North-central Poland.

Science.gov (United States)

Falandysz, Jerzy; Jedrusiak, Aneta; Lipka, Krzysztof; Kannan, Kurunthachalam; Kawano, Masahide; Gucia, Magdalena; Brzostowski, Andrzej; Dadej, Monika

2004-01-01

Concentrations of total mercury were determined by cold-vapour atomic absorption spectroscopy (CV-AAS) in 221 caps and 221 stalks of 15 species of wild growing higher fungi/mushrooms and 221 samples of corresponding soil substrate collected in 1997-98 in Manowo County, near the city of Koszalin in North-central Poland. Mean mercury concentrations in caps and stalks of the mushroom species examined and soils varied between 30+/-31 and 920+/-280, 17+/-11 and 560+/-220, and 10+/-9 and 170+/-110 ng/g dry matter, respectively. Cap to stalk mercury concentration quotients were from 1.0+/-0.4 in poison pax (Paxillus involutus) to 2.8+/-0.7 in slippery jack (Suillus luteus). Brown cort (Cortinarius malicorius), fly agaric (Amanita muscaria), orange-brown ringless amanita (A. fulva), red-aspen bolete (Leccinum rufum) and mutagen milk cap (Lactarius necator) contained the highest concentrations of mercury both in caps and stalks, and mean concentrations varied between 600+/-750 and 920+/-280 and 370+/-470 and 560+/-220 ng/g dry matter, respectively. An estimate of daily intake of mercury from mushroom consumption indicated that the flesh of edible species of mushrooms may not pose hazards to human health even at a maximum consumption rate of 28 g/day. However, it should be noted that mercury intake from other foods will augment the daily intake rates. Species such as the sickener (Russula emetica), Geranium-scented russula (R. fellea) and poison pax (P. involutus) did not concentrate mercury as evidenced from the bioconcentration factors (BCFs: concentrations in mushroom/concentration in soil substrate), which were less than 1. Similarly, red-hot milk cap (L. rufus), rickstone funnel cap (Clitocybe geotropa) and European cow bolete (S. bovinus) were observed to be weak accumulators of mercury. Fly agaric (A. muscaria) accumulated great concentrations of mercury with BCFs reaching 73+/-42 and 38+/-22 in caps and stalks, respectively. Mercury BCFs of between 4.0+/-2.3 and 23

Compost improves urban soil and water quality

Science.gov (United States)

Construction in urban zones compacts the soil, which hinders root growth and infiltration and may increase erosion, which may degrade water quality. The purpose of our study was to determine the whether planting prairie grasses and adding compost to urban soils can mitigate these concerns. We simula...

Interannual observations and quantification of summertime H2O ice deposition on the Martian CO2 ice south polar cap

Science.gov (United States)

Brown, Adrian J.; Piqueux, Sylvain; Titus, Timothy N.

2014-01-01

The spectral signature of water ice was observed on Martian south polar cap in 2004 by the Observatoire pour l'Mineralogie, l'Eau les Glaces et l'Activite (OMEGA) ( Bibring et al., 2004). Three years later, the OMEGA instrument was used to discover water ice deposited during southern summer on the polar cap ( Langevin et al., 2007). However, temporal and spatial variations of these water ice signatures have remained unexplored, and the origins of these water deposits remains an important scientific question. To investigate this question, we have used observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter (MRO) spacecraft of the southern cap during austral summer over four Martian years to search for variations in the amount of water ice. We report below that for each year we have observed the cap, the magnitude of the H2O ice signature on the southern cap has risen steadily throughout summer, particularly on the west end of the cap. The spatial extent of deposition is in disagreement with the current best simulations of deposition of water ice on the south polar cap (Montmessin et al., 2007). This increase in water ice signatures is most likely caused by deposition of atmospheric H2O ice and a set of unusual conditions makes the quantification of this transport flux using CRISM close to ideal. We calculate a ‘minimum apparent‘ amount of deposition corresponding to a thin H2O ice layer of 0.2 mm (with 70% porosity). This amount of H2O ice deposition is 0.6–6% of the total Martian atmospheric water budget. We compare our ‘minimum apparent’ quantification with previous estimates. This deposition process may also have implications for the formation and stability of the southern CO2 ice cap, and therefore play a significant role in the climate budget of modern day Mars.

Water repellency of two forest soils after biochar addition

Science.gov (United States)

D. S. Page-Dumroese; P. R. Robichaud; R. E. Brown; J. M. Tirocke

2015-01-01

Practical application of black carbon (biochar) to improve forest soil may be limited because biochar is hydrophobic. In a laboratory, we tested the water repellency of biochar application (mixed or surface applied) to two forest soils of varying texture (a granitic coarse-textured Inceptisol and an ash cap fine-textured Andisol) at four different application rates (0...

The influence of organic matter content and media compaction on the dispersal of entomopathogenic nematodes with different foraging strategies.

Science.gov (United States)

Kapranas, Apostolos; Maher, Abigail M D; Griffin, Christine T

2017-12-01

In laboratory experiments, we investigated how media with varying ratio of peat:sand and two levels of compaction influence dispersal success of entomopathogenic nematode (EPN) species with different foraging strategies: Steinernema carpocapsae (ambusher), Heterorhabditis downesi (cruiser) and Steinernema feltiae (intermediate). Success was measured by the numbers of nematodes moving through a 4 cm column and invading a wax moth larva. We found that both compaction and increasing peat content generally decreased EPN infective juvenile (IJ) success for all three species. Of the three species, H. downesi was the least affected by peat content, and S. carpocapsae was the most adversely influenced by compaction. In addition, sex ratios of the invading IJs of the two Steinernema species were differentially influenced by peat content, and in the case of S. feltiae, sex ratio was also affected by compaction. This indicates that dispersal of male and female IJs is differentially affected by soil parameters and that this differentiation is species-specific. In conclusion, our study shows that organic matter: sand ratio and soil compaction have a marked influence on EPN foraging behaviour with implications for harnessing them as biological pest control agents.

Effects of Tillage Practices on Soil Organic Carbon and Soil Respiration

Science.gov (United States)

Rusu, Teodor; Ioana Moraru, Paula; Bogdan, Ileana; Ioan Pop, Adrian

2016-04-01

Soil tillage system and its intensity modify by direct and indirect action soil temperature, moisture, bulk density, porosity, penetration resistance and soil structural condition. Minimum tillage and no-tillage application reduce or completely eliminate the soil mobilization, due to this, soil is compacted in the first years of application. The degree of compaction is directly related to soil type and its state of degradation. All this physicochemical changes affect soil biology and soil respiration. Soil respiration leads to CO2 emissions from soil to the atmosphere, in significant amounts for the global carbon cycle. Soil respiration is one measure of biological activity and decomposition. Soil capacity to produce CO2 varies depending on soil, season, intensity and quality of agrotechnical tillage, soil water, cultivated plant and fertilizer. Our research follows the effects of the three tillage systems: conventional system, minimum tillage and no-tillage on soil respiration and finally on soil organic carbon on rotation soybean - wheat - maize, obtained on an Argic Faeoziom from the Somes Plateau, Romania. To quantify the change in soil respiration under different tillage practices, determinations were made for each crop in four vegetative stages (spring, 5-6 leaves, bean forming, harvest). Soil monitoring system of CO2 and O2 included gradient method, made by using a new generation of sensors capable of measuring CO2 concentration in-situ and quasi-instantaneous in gaseous phase. At surface soil respiration is made by using ACE Automated Soil CO2 Exchange System. These areas were was our research presents a medium multi annual temperature of 8.20C medium of multi annual rain drowns: 613 mm. The experimental variants chosen were: i). Conventional system: reversible plough (22-25 cm) + rotary grape (8-10 cm); ii). Minimum tillage system: paraplow (18-22 cm) + rotary grape (8-10 cm); iii). No-tillage. The experimental design was a split-plot design with three

ATLAS electromagnetic end-cap detector

CERN Multimedia

Maximilien Brice

2003-01-01

After the insertion of the first end-cap into this cryostat, the team proceed to the wiring operations. Millions of wires are connected to the electromagnetic calorimeter on this end-cap, whch must be carefully fed out from the detector so that data can be read out. The energy of photons, electrons and positrons will be measured as they pass through the end-cap having been created along the line of the beams in the proton-proton collisions.

ATLAS end-cap detector

CERN Multimedia

Maximilien Brice

2003-01-01

Three scientists from the Institute of Nuclear Phyiscs at Novossibirsk with one of the end-caps of the ATLAS detector. The end-caps will be used to detect particles produced in the proton-proton collisions at the heart of the ATLAS experiment that are travelling close to the axis of the two beams.

The use of light weight deflectometer for in situ evaluation of sand degree of compaction

Directory of Open Access Journals (Sweden)

Amr F. Elhakim

2014-12-01

Full Text Available The light weight deflectometer (LWD, also known as the light falling weight deflectometer, light drop weight tester, and dynamic plate load test, is a hand portable device that was developed in Germany to measure the soil in situ LWD dynamic modulus. Typically, this modulus is used to evaluate the subsoil degree of compaction. Thus it is suitable for compaction quality control of soil-surfaced roads, embankments and replacement fill. As a dynamic test, the device is suited, in particular, for coarse and mixed grained soils with a maximum grain size of 63 mm. The response of poorly graded calcareous and siliceous sands is the focus of this research. First, the index soil properties of the tested soils including grain size distribution; maximum and minimum void ratios and specific gravity were obtained. Petrographic analyses of the tested sands were also performed to determine their mineralogical composition. A 1-m3 chamber was built for performing the LWD testing in the laboratory. The study was performed for relative densities of 20%, 40%, 60% and 80% to represent the behavior of very loose, loose, medium dense and dense sands. The effect of the existence of a rigid boundary beneath the tested soil on test results was also investigated to determine the zone of influence of the light weight deflectometer.

Compact polarimetric synthetic aperture radar for monitoring soil moisture condition

Science.gov (United States)

Merzouki, A.; McNairn, H.; Powers, J.; Friesen, M.

2017-12-01

Coarse resolution soil moisture maps are currently operationally delivered by ESA's SMOS and NASA's SMAP passive microwaves sensors. Despite this evolution, operational soil moisture monitoring at the field scale remains challenging. A number of factors contribute to this challenge including the complexity of the retrieval that requires advanced SAR systems with enhanced temporal revisit capabilities. Since the launch of RADARSAT-2 in 2007, Agriculture and Agri-Food Canada (AAFC) has been evaluating the accuracy of these data for estimating surface soil moisture. Thus, a hybrid (multi-angle/multi-polarization) retrieval approach was found well suited for the planned RADARSAT Constellation Mission (RCM) considering the more frequent relook expected with the three satellite configuration. The purpose of this study is to evaluate the capability of C-band CP data to estimate soil moisture over agricultural fields, in anticipation of the launch of RCM. In this research we introduce a new CP approach based on the IEM and simulated RCM CP mode intensities from RADARSAT-2 images acquired at different dates. The accuracy of soil moisture retrieval from the proposed multi-polarization and hybrid methods will be contrasted with that from a more conventional quad-pol approach, and validated against in situ measurements by pooling data collected over AAFC test sites in Ontario, Manitoba and Saskatchewan, Canada.

21 CFR 884.5250 - Cervical cap.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix to...

21 CFR 888.3000 - Bone cap.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone cap. 888.3000 Section 888.3000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3000 Bone cap. (a) Identification. A bone cap is a mushroom...

Genetic ablation of root cap cells in Arabidopsis

OpenAIRE

Tsugeki, Ryuji; Fedoroff, Nina V.

1999-01-01

The root cap is increasingly appreciated as a complex and dynamic plant organ. Root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. However, it is not known whether root caps are essential for normal shoot and root development. We report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of...

FEM simulation of the die compaction of pharmaceutical products: influence of visco-elastic phenomena and comparison with experiments.

Science.gov (United States)

Diarra, Harona; Mazel, Vincent; Busignies, Virginie; Tchoreloff, Pierre

2013-09-10

This work studies the influence of visco-elastic behavior in the finite element method (FEM) modeling of die compaction of pharmaceutical products and how such a visco-elastic behavior may improve the agreement between experimental and simulated compression curves. The modeling of the process was conducted on a pharmaceutical excipient, microcrystalline cellulose (MCC), by using Drucker-Prager cap model coupled with creep behavior in Abaqus(®) software. The experimental data were obtained on a compaction simulator (STYLCAM 200R). The elastic deformation of the press was determined by performing experimental tests on a calibration disk and was introduced in the simulation. Numerical optimization was performed to characterize creep parameters. The use of creep behavior in the simulations clearly improved the agreement between the numerical and experimental compression curves (stresses, thickness), mainly during the unloading part of the compaction cycle. For the first time, it was possible to reproduce numerically the fact that the minimum tablet thickness is not obtained at the maximum compression stress. This study proves that creep behavior must be taken into account when modeling the compaction of pharmaceutical products using FEM methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of Rice Husk Ash on Soil Stabilization

OpenAIRE

Muhammad Qasim; Aroj Bashir; Mubashar Tanvir; Malik Muhammad Anees

2015-01-01

The soil frequently is fragile and has low stability in heavy loading. The objective of this study is to review the stabilization of soil using sustainable methods. Some strengthening approaches are available for stabilization of expansive soils. These methods consist of stabilization with soil replacement, chemical additives, moisture control, rewetting, surcharge loading, compaction control and thermal methods. The disadvantages may be associated with all these methods due to ineffectivenes...

CENTRIFUGE END CAP

Science.gov (United States)

Beams, J.W.; Snoddy, L.B.

1960-08-01

An end cap for ultra-gas centrifuges is designed to impart or remove angular momentum to or from the gas and to bring the entering gas to the temperature of the gas inside the centrifuge. The end cap is provided with slots or fins for adjusting the temperature and the angular momentum of the entering gas to the temperature and momentum of the gas in the centrifuge and is constructed to introduce both the inner and the peripheral stream into the centrifuge.

Permeability Characteristics of Compacted and Stabilized Clay with Cement, Peat Ash and Silica Sand

Directory of Open Access Journals (Sweden)

Seyed Esmaeil Mousavi

2016-06-01

Full Text Available The present paper investigates the influence of stabilization with cement, peat ash, and silica sand on permeability coefficient (kv of compacted clay, using a novel approach to stabilize the clay with peat ash as a supplementary material of cement in the compacted and stabilized soil. In order to assess the mentioned influence, test specimens of both untreated and stabilized soil have been tested in the laboratory so that their permeability could be evaluated. Falling head and one dimensional consolidation tests of laboratory permeability were performed on the clay specimens and the chemical compositions of the materials as well as microstructure of the stabilized soil with 18% cement, 2% peat ash, and 5% silica sand were investigated, using X-ray fluorescence and scanning electron microscopy respectively. Results show that for soil stabilization with up to 8% cement content (of the dry weight of the soil, the average value of coefficient of permeability (kv is very close to that of untreated soil, whereas the kv value decreases drastically for 18% cement under identical void ratio conditions. It is further revealed that addition of 18% cement, 2% peat ash, and 5% silica sand had decreased the coefficient of permeability by almost 2.2 folds after 24 h, while about 1.7 folds increase was observed in coefficient of permeability once 13.5% of cement, 1.5% of peat ash, and 20% of silica sand were added. The partial replacement of cement with the 2% peat ash can reduce the consumption of cement for soil stabilization.

THE TURN OF THE MONTH EFFECT CONTINUED: A COMPARISON OF SMALL CAP STOCKS AND LARGE CAP STOCKS

OpenAIRE

Ramsundhar, Shamman

2010-01-01

The purpose of this paper is to investigate whether the turn of the month effect occurs in small cap and large cap stocks and if it occurs in both categories, to determine whether there is a difference in the magnitude. My research, for the period of 1963-2008, based on the CRSP value weighted index, shows that there is a significant turn of the month effect in small and large cap stocks, however the effect is larger in small cap stocks. Furthermore, this effect is not limited to a short time...

Soil quality attributes induced by land use changes in the Fincha'a ...

African Journals Online (AJOL)

Soil quality attributes induced by land use changes in the Fincha'a ... from the upstream to the downstream irrigated land by water soil erosion. ... The main degradation process overcome the study area was waterlogging and soil compaction.

Soil precompression stress, penetration resistance and crop yields in relation to differently-trafficked, temperate-region sandy loam soils

DEFF Research Database (Denmark)

Schjønning, Per; Lamandé, Mathieu; Munkholm, Lars Juhl

2016-01-01

. Undisturbed soil cores were used for quantifying the precompression stress (spc) of non-compacted soil. Tractor-trailer combinations for slurry application with wheel loads of 3, 6 and 8 Mg (treatments M3, M6, M8) were used for the experimental traffic in the spring at field-capacity. For one additional...

Heavy-machinery traffic impacts methane emissions as well as methanogen abundance and community structure in oxic forest soils.

Science.gov (United States)

Frey, Beat; Niklaus, Pascal A; Kremer, Johann; Lüscher, Peter; Zimmermann, Stephan

2011-09-01

Temperate forest soils are usually efficient sinks for the greenhouse gas methane, at least in the absence of significant amounts of methanogens. We demonstrate here that trafficking with heavy harvesting machines caused a large reduction in CH(4) consumption and even turned well-aerated forest soils into net methane sources. In addition to studying methane fluxes, we investigated the responses of methanogens after trafficking in two different forest sites. Trafficking generated wheel tracks with different impact (low, moderate, severe, and unaffected). We found that machine passes decreased the soils' macropore space and lowered hydraulic conductivities in wheel tracks. Severely compacted soils yielded high methanogenic abundance, as demonstrated by quantitative PCR analyses of methyl coenzyme M reductase (mcrA) genes, whereas these sequences were undetectable in unaffected soils. Even after a year after traffic compression, methanogen abundance in compacted soils did not decline, indicating a stability of methanogens here over time. Compacted wheel tracks exhibited a relatively constant community structure, since we found several persisting mcrA sequence types continuously present at all sampling times. Phylogenetic analysis revealed a rather large methanogen diversity in the compacted soil, and most mcrA gene sequences were mostly similar to known sequences from wetlands. The majority of mcrA gene sequences belonged either to the order Methanosarcinales or Methanomicrobiales, whereas both sites were dominated by members of the families Methanomicrobiaceae Fencluster, with similar sequences obtained from peatland environments. The results show that compacting wet forest soils by heavy machinery causes increases in methane production and release.

Indicators of structural degradation on intensively cultivated soils of the Piedemonte Llanero

International Nuclear Information System (INIS)

Obando, Franco H

2000-01-01

In order to evaluate the validity of a diagnosis methodology of structural soil degradation based on the combination of internal morphology of aggregates and measurement of resistance to penetration, a reconnaissance survey of physical degradation processes on intensively cultivated soils in the Piedemonte Llanero was carried out. The internal morphology of soil aggregates was classified into five states; micro-aggregate (μ), compacted (∇ μ), very compacted (∇), cracked compacted (φ) and agglomerate (ψ) defined according to morphological characteristics derived from cultivation practices and wheel traffic. Two crops systems were selected: low-lying rice (mono-cropping) during 30 years) and upland rice, maize, soybean cotton crop rotations during 20 years in two landscapes of the alluvial plain of piedmont (medium terraces of the sub-recent piedmont, TM, and No-flooding Lowland Flats of the Recent Piedmont, PR). A natural forest and 20 years cacao tree plantation was include as benchmark systems. It was found that higher values of resistance to penetration and total density are associated to compact layers (∇ μ, ∇ and φ states) and lower values to the μ a ψ states. The ∇ state was particularly evident on TM under mono-cropping e low-lying rice crop. High values of resistance to penetration of topsoil on PR were rather associated to e textural resistance. Under natural forest and cacao e plantation it was found the micro-aggregate state (μ) o on surface soil. High values of weighed mean diameter of water stable aggregates, DMP, (≥ 5mm) were associated to compacted layers in the crop rotation e systems in PR. it was demonstrated that this methodology developed in France (temperate zone) can be applied to tropical soils

Frost Heave in Colloidal Soils

KAUST Repository

Peppin, Stephen

2011-01-01

We develop a mathematical model of frost heave in colloidal soils. The theory accountsfor heave and consolidation while not requiring a frozen fringe assumption. Two solidificationregimes occur: a compaction regime in which the soil consolidates to accommodate the ice lenses, and a heave regime during which liquid is sucked into the consolidated soil from an external reservoir, and the added volume causes the soil to heave. The ice fraction is found to vary inversely with thefreezing velocity V , while the rate of heave is independent of V , consistent with field and laboratoryobservations. © 2011 Society for Industrial and Applied Mathematics.

Soil resistance and resilience to mechanical stresses for three differently managed sandy loam soils

DEFF Research Database (Denmark)

Arthur, Emmanuel; Schjønning, Per; Møldrup, Per

2012-01-01

carbon (CCCsoils to compaction using air permeability (ka), void ratio (e) and air-filled porosity (ε) as functional indicators and to characterise aggregate stability, strength and friability. Aggregate tensile strength...... the compression index and a proposed functional index,was significantly greater for theMFC soil compared to the other two soils. The change in compression index with initial void ratio was significantly less for the MFC than the other soils. Plastic reorganisation of the soil particles immediately after......To improve our understanding of how clay-organic carbon dynamics affect soil aggregate strength and physical resilience, we selected three nearby soils (MFC,Mixed Forage Cropping; MCC,Mixed Cash Cropping; CCC, Cereal Cash Cropping)with identical clay content and increasing contents of organic...

Influence of wood-derived biochar on the physico-mechanical and chemical characteristics of agricultural soils

Science.gov (United States)

Ahmed, Ahmed S. F.; Raghavan, Vijaya

2018-01-01

Amendment of soil with biochar has been shown to enhance fertility and increase crop productivity, but the specific influence of biochar on soil workability remains unclear. Select physico-mechanical and chemical properties of clay loam and sandy loam soils were measured after amendment with wood-derived biochar of two particle size ranges (0.5-425 and 425-850 µm) at five dosages ranging from 0.5 to 10% dry weight. Whereas the clay loam soil workability decreased when the finer wood-derived biochar was applied at rates of 6 or 10%, soil fertility was not enhanced. The sandy loam soil, due to Proctor compaction, significantly decreased in bulk density with 6 and 10% wood-derived biochar amendments indicating higher soil resistance to compaction.

Managing soil moisture on waste burial sites in arid regions

International Nuclear Information System (INIS)

Anderson, J.E.; Ratzlaff, T.D.; Nowak, R.S.; Markham, O.D.

1993-01-01

In semiarid regions, where potential evapotranspiration greatly exceeds precipitation, it is theoretically possible to preclude water form reaching interred wastes by (i) providing a sufficient cap of soil to store precipitation that falls while plants are dormant and (ii) establishing sufficient plant cover to deplete soil moisture during the growing season, thereby emptying the water storage reservoir of the soil. Here the authors discuss the theory and rationale for such an approach and then present the results of a field study to test its efficacy at the Idaho National Engineering Laboratory (INEL). They examined the capacity of four species of perennial plants to deplete soil moisture on simulated waste trenches and determined the effective water storage capacity of the soil. Those data enabled them to estimate the minimum depth of fill soil required to prevent deep drainage. Any of the species studied can use all of the plant-available soil water, even during a very wet growing season. The water storage capacity of the soil studied is 17% by volume, so a trench cap of 1.6 m of soil should be adequate to store precipitation received at the INEL while plants are dormant. They recommend a fill soil depth of 2 m to provide a margin of safety in case water accumulates in local areas as a result of heavy snow accumulation, subsidence, or runoff. Fill soil requirements and choice of plant species will vary, but the concepts and general approach are applicable to other shallow land burial sites in arid or semiarid regions. 23 refs., 5 figs

CONSIDERATIONS ON URBAN SOILS

Directory of Open Access Journals (Sweden)

Radu Lacatusu

2005-10-01

Full Text Available Urban soil is an material that has been manipulated, disturbed or transported by man’s activities in the urban environment and is used as a medium for plant growth and for constructions. The physical, chemical, and biological properties are generally less favorable as a rooting medium than soil found on the natural landscape. The main characteristics of urban soils are: great vertical and spatial variability; modified soil structure leading to compaction; presence of a surface crust; modified soil reaction, usually elevated; restricted aeration and water drainage; modified abundance of chemical elements, interrupted nutrient cycling and soil organism activity; presence of anthropic materials contaminants and pollutants; modified soil temperature regime. The urbic horizon is designated as U (always capital letter and for indication of processes are used different small letters. It is necessary elaboration a new classification of urban soils for our country.

Design and Performance Assessment of a Conceptual Cover Cap of Near Surface Repository for Short Lived Low and Intermediate Level Radioactive Waste

Energy Technology Data Exchange (ETDEWEB)

Asaba, Ruth; Kim, Changlak [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2014-05-15

The safety of the overall waste disposal system is determined by the performance of its individual components: waste form, waste container, engineered barrier and the host environment. The design of the cover cap helps in preventing percolation of water, and in retarding radionuclide migration from the disposal facility to the biosphere. The cover of a disposal facility is usually a combination of materials such as sand, gravel, concrete, clay and soil conditioned for vegetation growth. The cover system will be designed using models such as EPA's Hydrological Evaluation of Land fill Performance (HELP) code. This paper describes a conceptual design for a cover cap for a land fill as a preferred disposal facility for low and short lived intermediate radioactive waste in Uganda. Majority of the waste is generated from disused sealed and unsealed radioactive sources arising from medical, industrial applications, and research. Radioactive waste management has raised a lot of concern in both developed and developing countries. Each country has a responsibility to come up with a solution to prevent contamination of the environment and humans from radioactive waste. It is important to have thicker soil layers in cap designs so as to support vegetation growth since some activities such as erosion and settlements are expected. Help simulations in this study will assist to demonstrate that it is possible to design a cover cap which can contain radioactive waste packages for hundreds of years provided the proper institutional and performance monitoring schemes are implemented.

Spatial analysis of subsoil compaction on cultivated land by means of penetrometry, electrical resistence tomography and X-ray computed tomography

Science.gov (United States)

Zumr, David; Vláčilová, Markéta; Dostál, Tomáš; Jeřábek, Jakub; Sobotková, Martina; Sněhota, Michal

2015-04-01

Soil compaction is a well recognized phenomena in the agricultural land. Various effects can alter the degree of the compaction in the field. The topsoil is regularly loosened due to agrotechnical operations, but the subsoil remains usually compacted. Various studies show increasing bulk density and decreasing saturated hydraulic conductivity in the plough pan, even though some authors argue that it does not have to be always the case due to presence of bio-macropores. Hence the structural properties of the subsoil and the spatial distribution of the compacted layer depth within the cultivated fields are important factors influencing soil water regime, nutrients regime and runoff generation. The aim of the contribution is to present the results of the monitoring of the plough pan depth spatial distribution at the experimental catchment Nucice (Central Bohemia, Czech Republic). The soils are classified as Luvisols and Cambisols with a loamy Ap horizon (0.1 - 0.2 m deep) underlined by a silty and silty-clay B horizon. The content of clay particles in the topsoil is around 8%. The soil has low inner aggregate (soil matrix) hydraulic conductivity, with measured values of approximately 0.1 - 2 cm d-1. The bulk topsoil saturated hydraulic conductivity (Ks) is significantly higher and varies depending on the season. To observe the divide between topsoil and subsoil layers in detail and to be able to compare the soil structure and pore networks of both layers we inspected undisturbed soil samples with X-ray computed tomography. The divide between the conservatively tilled topsoil and the subsoil is clearly observable also on terrain. To identify its exact position we implemented a combination of penetrometry, soil sampling and electrical resistance tomography (ERT). The penetration tests accompanied by soil probing were done in an irregular network across the whole catchment based on the slopes and distance to the stream. Several 2D ERT measurements were done locally on a

LOAD DISTRIBUTION ON SOIL PROFILE AS GENERATED BY FARM MACHINERY TIRES/COMPACTAÇÃO DO SOLO GERADOS POR PNEUS DE MÁQUINAS AGRÍCOLAS.

Directory of Open Access Journals (Sweden)

Daniel ALBIERO

2008-11-01

Full Text Available ABSTRACTSoil compaction is considered as a major agricultural problem which is close associated to agricultural productivity. This way, the sources of soil compaction should be identified and conveniently studied, so the interacting factors can be considered to propose a future mathematical model. Great part of Brazilian tractors is equipped with tires, which are recognized to generate soil compaction. This research work proposes the application of the shadow Moiré technique to mapstrain distribution on soil profile as well as density increase due to the action of loads generated by tractor tires. Iso-strain curves generated from more fringes.KEYWORDS: Tires, Moiré, Soil Compaction.

Soil Degradation Processes; Procesos de Degradacion del Suelo

Energy Technology Data Exchange (ETDEWEB)

Nunez Crespi, S; Perez Martinez, M; Cuesta Santianes, M J; Cabrera Jimenez, J A

2007-12-28

In the European communication entitled Towards a Thematic Strategy for Soil Protection, eight main threats to soil were identified: contamination, erosion, loss of organic matter, compaction, salinization; hydro-geological risks, soil sealing, and decline in biodiversity. The main purpose of this report is to provide the current state of knowledge of the soil degradation processes both, in the European Community scale and, particularly, in the Spanish territory. Furthermore, the main research project information related to soil degradation processes is also included, identifying the main actors involved in soil scientific research and development. (Author) 66 refs.

Improvement of clayey soil characteristics by using activated carbon

Directory of Open Access Journals (Sweden)

Al-Soudany Kawther

2018-01-01

Full Text Available The clay soil is weak and unable to carry the applied loads as a result of the weight of buildings or vehicles on the load performing on the soil. In this research, clay soil was grained and mixed with different percentages of activated carbon additives to investigate its performance. One type of clay soil from Al-Taji city was used. The percentages of activated carbon 3, 5, 7 and 9% were added to the soil and the influence of the admixture was observed by comparing the results with the untreated soil. The selected properties for this comparison were specific gravity, consistency limits, compaction, static compaction, CBR, consolidation, swelling and unconfined compressive strength. The results showed that the plasticity index, maximum dry weight and specific gravity decreased as the percentage of additives increased. The unconfined compressive strength increased as the percentage of additives and curing periods (1, 7, 14 and 28days increased. The amount of increase in soil strength was even more than 100% for the 9% activatedcarbon. The results showed that the addition of activated carbon has a positive effect to the geotechnical properties.

Assessment of soil sample quality used for density evaluations through computed tomography

International Nuclear Information System (INIS)

Pires, Luiz F.; Arthur, Robson C.J.; Bacchi, Osny O.S.

2005-01-01

There are several methods to measure soil bulk density (ρ s ) like the paraffin sealed clod (PS), the volumetric ring (VR), the computed tomography (CT), and the neutron-gamma surface gauge (SG). In order to evaluate by a non-destructive way the possible modifications in soil structure caused by sampling for the PS and VR methods of ρ s evaluation we proposed to use the gamma ray CT method. A first generation tomograph was used having a 241 Am source and a 3 in x 3 in NaI(Tl) scintillation crystal detector coupled to a photomultiplier tube. Results confirm the effect of soil sampler devices on the structure of soil samples, and that the compaction caused during sampling causes significant alterations of soil bulk density. Through the use of CT it was possible to determine the level of compaction and to make a detailed analysis of the soil bulk density distribution within the soil sample. (author)

Sub-ppm analysis using a compact EDX

International Nuclear Information System (INIS)

Muraoka, Koichi; Utaka, Tadashi; Taniguchi, Kazuo

2009-01-01

As an important solution for the Soil Contamination Countermeasures Laws and China RoHS as well as EU WEEE/RoHS/ELV Directives, an EDX analyzer has been utilized as a simple and convenient instrument for promptly screening the hazardous heavy elements with high reproducibility in non-destructive manner. However, with the increasing varieties of measuring samples, the development of a high performance, more convenient and portable instrument has been expected. To meet these demands, based on the compact X-ray optical technology, using a miniature X-ray tube, a primary beam filter method and portable semiconductor detector with Peltier cooling system, we have developed a high-performance EDX Analyzer. In this study, thus, the hardware configurations and the obtained research results for sub-ppm analysis of Cd in brown rice and soil are reported. (author)

Assessment of Real-Time Compaction Quality Test Indexes for Rockfill Material Based on Roller Vibratory Acceleration Analysis

Directory of Open Access Journals (Sweden)

Tianbo Hua

2018-01-01

Full Text Available Compaction quality is directly related to the structure and seepage stability of a rockfill dam. To timely and accurately test the compaction quality of the rockfill material, four real-time test indexes were chosen to characterize the soil compaction degree based on the analysis of roller vibratory acceleration, including acceleration peak value (ap, acceleration root mean square value (arms, crest factor value (CF, and compaction meter value (CMV. To determine which of these indexes is the most appropriate, a two-part field compaction experiment was conducted using a vibratory roller in different filling zones of the dam body. Data on rolling parameters, real-time test indexes, and compaction quality indexes were collected to perform statistical regression analyses. Combined with the spectrum analysis of the acceleration signal, it was found that the CF index best characterizes the compaction degree of the rockfill material among the four indexes. Furthermore, the quantitative relations between the real-time index and compaction quality index were established to determine the control criterion of CF, which can instruct the site work of compaction quality control in the rockfill rolling process.

Disposal of decontaminated salts at the Savannah River Plant by solidification and burial

International Nuclear Information System (INIS)

Dukes, M.D.; Wolf, H.C.; Langton, C.A.

1983-01-01

The current plan for disposal of waste salt at the Savannah River Plant (SRP) is to immobilize the decontaminated salt solution by mixing with cement and SRP soil, and bury the resulting grout (saltstone) in a landfill. The grout which contains 37.8 wt % salt solution, 22.8 wt % Portland I-P cement, and 39.2 wt % SRP soil, was specially formulated to have a low permeability ( -10 cm/sec). This material will be mixed and placed in trenches. After setting, the saltstone will be covered with a clay cap, and an overburden of compacted native soil will be replaced. 6 references

Revision of Drucker-Prager cap creep modelling of pebble beds in fusion blankets

International Nuclear Information System (INIS)

Hofer, D.; Kamlah, M.; Hermsmeyer, S.

2004-01-01

A continuum model commonly used in soil mechanics analysis is compiled by use of a finite element software and has been used to simulate the thermomechanical behaviour of pebble beds. The Drucker-Prager Cap theory accounts for inelastic volume change, cap hardening, nonlinear elasticity and pressure dependent shear failure. The hardening mechanism allows for defining the hydrostatic pressure yield stress as a function of the volumetric inelastic strain. Volumetric creep is considered in order to simulate the pebble bed behaviour at high temperatures. Here, the strain hardening option has been used for the consolidation creep mechanism. The model has been calibrated using the fitting curves of the oedometric test given by Reimann et al. The fitted data has been used to calculate a pebble bed with simplified boundary conditions loaded by non-uniform volumetric heating. This calculation demonstrated that the model is capable of representing creep behaviour under volumetric heating conditions. (author)

Analyses of hydraulic performance of velocity caps

DEFF Research Database (Denmark)

Christensen, Erik Damgaard; Degn Eskesen, Mark Chr.; Buhrkall, Jeppe

2014-01-01

The hydraulic performance of a velocity cap has been investigated. Velocity caps are often used in connection with offshore intakes. CFD (computational fluid dynamics) examined the flow through the cap openings and further down into the intake pipes. This was combined with dimension analyses...

Ground Freezing Effects on Soil Erosion of Army Training Lands Part 1: Initial Test Results

National Research Council Canada - National Science Library

Gatto, Lawrence

1997-01-01

...) processes can change the hydraulic geometry and roughness of vehicular ruts and reduce soil compaction, which often partially restores the water infiltration rate that existed before compaction...

49 CFR 230.41 - Flexible staybolts with caps.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Flexible staybolts with caps. 230.41 Section 230... Appurtenances Staybolts § 230.41 Flexible staybolts with caps. (a) General. Flexible staybolts with caps shall have their caps removed during every 5th annual inspection for the purpose of inspecting the bolts for...

Comparative Response of Four Pedogenic Soil Materials to Cement ...

African Journals Online (AJOL)

A comparative response of four Pedogenic soil materials to cement stabilization was investigated. The studies focused on the compaction characteristics, the unconfined sompressive strength and the California bearing ratio of the samples. The results obtained show that soil materials from Maiduguri responded favorably to ...

Can urban tree roots improve infiltration through compacted subsoils for stormwater management?

Science.gov (United States)

Bartens, Julia; Day, Susan D; Harris, J Roger; Dove, Joseph E; Wynn, Theresa M

2008-01-01

Global land use patterns and increasing pressures on water resources demand creative urban stormwater management. Strategies encouraging infiltration can enhance groundwater recharge and water quality. Urban subsoils are often relatively impermeable, and the construction of many stormwater detention best management practices (D-BMPs) exacerbates this condition. Root paths can act as conduits for water, but this function has not been demonstrated for stormwater BMPs where standing water and dense subsoils create a unique environment. We examined whether tree roots can penetrate compacted subsoils and increase infiltration rates in the context of a novel infiltration BMP (I-BMP). Black oak (Quercus velutina Lam.) and red maple (Acer rubrum L.) trees, and an unplanted control, were installed in cylindrical planting sleeves surrounded by clay loam soil at two compaction levels (bulk density = 1.3 or 1.6 g cm(-3)) in irrigated containers. Roots of both species penetrated the more compacted soil, increasing infiltration rates by an average of 153%. Similarly, green ash (Fraxinus pennsylvanica Marsh.) trees were grown in CUSoil (Amereq Corp., New York) separated from compacted clay loam subsoil (1.6 g cm(-3)) by a geotextile. A drain hole at mid depth in the CUSoil layer mimicked the overflow drain in a stormwater I-BMP thus allowing water to pool above the subsoil. Roots penetrated the geotextile and subsoil and increased average infiltration rate 27-fold compared to unplanted controls. Although high water tables may limit tree rooting depth, some species may be effective tools for increasing water infiltration and enhancing groundwater recharge in this and other I-BMPs (e.g., raingardens and bioswales).

Models for prediction of soil precompression stress from readily available soil properties

DEFF Research Database (Denmark)

Schjønning, Per; Lamandé, Mathieu

2018-01-01

matric potentials. σpc was estimated from the original stress-strain curves by a novel, numerical method for estimating the stress at maximum curvature, assumingly partitioning the curve into elastic and plastic sections. Multiple regression was used to identify the drivers best describing the variation......Compaction of the subsoil is an almost irreversible damage to the soil resource. Modern machinery exerts high mechanical stresses to the subsoil, and a range of studies report significant effects on soil functions. There is an urgent need for quantitative knowledge of soil strength in order...... to evaluate sustainability of current field traffic. The aim of this study was to identify the most important drivers of soil precompression stress, σpc, and to develop pedotransfer functions for prediction of σpc. We revisited previously published data on σpc for a silty clay loam soil at a range of soil...

Shake table test of soil-pile groups-bridge structure interaction in liquefiable ground

Science.gov (United States)

Tang, Liang; Ling, Xianzhang; Xu, Pengju; Gao, Xia; Wang, Dongsheng

2010-03-01

This paper describes a shake table test study on the seismic response of low-cap pile groups and a bridge structure in liquefiable ground. The soil profile, contained in a large-scale laminar shear box, consisted of a horizontally saturated sand layer overlaid with a silty clay layer, with the simulated low-cap pile groups embedded. The container was excited in three El Centro earthquake events of different levels. Test results indicate that excessive pore pressure (EPP) during slight shaking only slightly accumulated, and the accumulation mainly occurred during strong shaking. The EPP was gradually enhanced as the amplitude and duration of the input acceleration increased. The acceleration response of the sand was remarkably influenced by soil liquefaction. As soil liquefaction occurred, the peak sand displacement gradually lagged behind the input acceleration; meanwhile, the sand displacement exhibited an increasing effect on the bending moment of the pile, and acceleration responses of the pile and the sand layer gradually changed from decreasing to increasing in the vertical direction from the bottom to the top. A jump variation of the bending moment on the pile was observed near the soil interface in all three input earthquake events. It is thought that the shake table tests could provide the groundwork for further seismic performance studies of low-cap pile groups used in bridges located on liquefiable groun.

Characterization of cap binding proteins associated with the nucleus

International Nuclear Information System (INIS)

Patzelt, E.

1986-04-01

Eucaryotic mRNAs a carry 7-methylguanosine triphosphate residue (called cap structure) at their 5' terminus. The cap plays an important role in RNA recognition. Cap binding proteins (CBP) of HeLa cells were identified by photoaffinity labelling using the cap analogue γ-( 32 P)-(4-(benzoyl-phenyl)methylamido)-7-methylguanosine-5'-triphosphate (BP-m 7 GTP). Photoreaction of this cap analogue with HeLa cell initiation factors resulted in specific labelling of two polypeptides of Msub(r) 37000 and 26000. The latter was also labelled in crude initiation factors prepared from reticulocytes and is identical to the cap binding protein CBP I previously identified. These cap binding proteins were also affinity labelled in poliovirus infected cell extracts. Photoaffinity reaction with BP-m 7 GTP of whole HeLa cell homogenate showed three additional polypeptides with Msub(r) 120000, 89000 and 80000. These cap binding proteins were found to be associated with the nucleus and are therefore referred to as nuclear cap binding proteins, i.e. NCBP 1, NCBP 2 and NCBP 3. They were also present in splicing extracts. Photoaffinity labelling in these nuclear extracts was differentially inhibited by various cap analogues and capped mRNAs. Affinity chromatography on immobilized globin mRNA led to a partial separation of the three nuclear cap binding proteins. Chromatography on m 7 GTP-Sepharose resulted in a specific binding of NCBP 3. The different behaviour of the cap binding proteins suggests that they are functionally distinct and that they might be involved in different processes requiring cap recognition. (Author)

Evaluation of the soil-seed environment through computerized tomography

International Nuclear Information System (INIS)

Modolo, Alcir Jose; Fernandes, Haroldo Carlos; Schaefer, Carlos Ernesto G.R.; Santos, Nerilson Terra; Silveira, Joao Cleber Modernel da

2008-01-01

The physical conditioning of the soil around seeds is of great importance for an adequate initial development of a crop, ensuring a healthy plant population. A suitable soil-seed contact is a prerequisite for a fast crop germination and good establishment. In this study, computerized tomography of millimeter resolution was used to determine the soil-seed environment in a no tillage system, immediately after soybean planting. A split plot design was used, in which the plots consisted of three contents of soil water, corresponding to 0.27; 0,31 and 0.36 kg kg -1 , respectively, and the split plots of four load levels applied by the compaction wheel, corresponding to 0, 50, 90 and 140 N, respectively. It was used a random block design, with four replications. The medium soil density in the seed area and the medium density profile in the sowing furrow were evaluated. According to the results, it may be concluded that: the loads applied by the compaction wheel increased soil density at the vertical planting level beneath planting depth as compared with values obtained before planting, and; the combination of wheel loads and soil water contents did not influence the mean soil density in the seed area. (author)

Mixed Waste Management Facility closure at the Savannah River Site

International Nuclear Information System (INIS)

Bittner, M.F.

1991-08-01

The Mixed Waste Management Facility of the Savannah River Plant received hazardous and solid low level radioactive wastes from 1972 until 1986. Because this facility did not have a permit to receive hazardous wastes, a Resource Conservation and Recovery Act closure was performed between 1987 and 1990. This closure consisted of dynamic compaction of the waste trenches and placement of a 3-foot clay cap, a 2-foot soil cover, and a vegetative layer. Operations of the waste disposal facility, tests performed to complete the closure design, and the construction of the closure cap are discussed herein

Theoretical model of polar cap auroral arcs

International Nuclear Information System (INIS)

Kan, J.R.; Burke, W.J.; USAF, Bedford, MA)

1985-01-01

A theory of the polar cap auroral arcs is proposed under the assumption that the magnetic field reconnection occurs in the cusp region on tail field lines during northward interplanetary magnetic field (IMF) conditions. Requirements of a convection model during northward IMF are enumerated based on observations and fundamental theoretical considerations. The theta aurora can be expected to occur on the closed field lines convecting sunward in the central polar cap, while the less intense regular polar cap arcs can occur either on closed or open field lines. The dynamo region for the polar cap arcs is required to be on closed field lines convecting tailward in the plasma sheet which is magnetically connected to the sunward convection in the central polar cap. 43 references

Effect of integrating straw into agricultural soils on soil infiltration and evaporation.

Science.gov (United States)

Cao, Jiansheng; Liu, Changming; Zhang, Wanjun; Guo, Yunlong

2012-01-01

Soil water movement is a critical consideration for crop yield in straw-integrated fields. This study used an indoor soil column experiment to determine soil infiltration and evaporation characteristics in three forms of direct straw-integrated soils (straw mulching, straw mixing and straw inter-layering). Straw mulching is covering the land surface with straw. Straw mixing is mixing straw with the top 10 cm surface soil. Then straw inter-layering is placing straw at the 20 cm soil depth. There are generally good correlations among the mulch integration methods at p soil infiltration, followed by straw mulching. Due to over-burden weight-compaction effect, straw inter-layering somehow retarded soil infiltration. In terms of soil water evaporation, straw mulching exhibited the best effect. This was followed by straw mixing and then straw inter-layering. Straw inter-layering could have a long-lasting positive effect on soil evaporation as it limited the evaporative consumption of deep soil water. The responses of the direct straw integration modes to soil infiltration and evaporation could lay the basis for developing efficient water-conservation strategies. This is especially useful for water-scarce agricultural regions such as the arid/semi-arid regions of China.

Crescimento radicular de soja em razão da sucessão de cultivos e da compactação do solo Soybean root growth as affected by previous crop and soil compaction

Directory of Open Access Journals (Sweden)

Rosemeire Helena da Silva

2002-06-01

Full Text Available O objetivo do experimento foi avaliar o crescimento radicular e produção de matéria seca da parte aérea da soja (Glycine max (L. Merrill cultivada após diversas espécies vegetais, em solo com diferentes níveis de compactação. O trabalho foi realizado em vasos contendo amostras de um Latossolo Vermelho, textura franco arenosa, com camada de 3,5 cm (profundidade de 15 a 18,5 cm compactada até as densidades 1,12, 1,36 e 1,60 Mg m-3, onde cultivaram-se anteriormente aveia-preta, guandu, milheto, mucuna-preta, soja, sorgo granífero e tremoço-azul, e um tratamento sem planta (pousio. Essas espécies se desenvolveram por 37 a 39 dias, foram cortadas ao nível do solo, picadas em partes de aproximadamente 3 cm e deixadas sobre a superfície do vaso por 40 dias. Após esse período, cultivou-se a soja até 28 dias após a emergência, quando, então, as plantas foram colhidas. Foram avaliados produção de matéria seca da parte aérea e de raízes, e comprimento e diâmetro radicular da soja. O cultivo anterior com aveia-preta, guandu e milheto favoreceu o crescimento radicular da soja abaixo de camadas compactadas do solo. Independentemente do nível de compactação, o cultivo anterior com qualquer das espécies estudadas beneficiou a produção de matéria seca da parte aérea da soja.This study aimed at evaluating root growth and shoot dry matter production of soybean (Glycine max (L. Merrill cropped after different vegetal species, in a soil with different compaction levels. The experiment was conducted in pots containing a Dark-Red Latosol (Acrortox, loamy sand, and the pots had a layer 3.5 cm (15 to 18.5 cm thick and 15 cm deep compacted to 1.12, 1.36 and 1.60 Mg m-3. Before soybean, the pots were cropped with black oat, pigeon pea, pearl millet, black mucuna, soybean, grain sorghum and lupin, plus a treatment without plants. These species were grown for 37 to 39 days, when they were cut at soil level, prick in particles of

Diagnostic criteria for cryopyrin-associated periodic syndrome (CAPS).

Science.gov (United States)

Kuemmerle-Deschner, Jasmin B; Ozen, Seza; Tyrrell, Pascal N; Kone-Paut, Isabelle; Goldbach-Mansky, Raphaela; Lachmann, Helen; Blank, Norbert; Hoffman, Hal M; Weissbarth-Riedel, Elisabeth; Hugle, Boris; Kallinich, Tilmann; Gattorno, Marco; Gul, Ahmet; Ter Haar, Nienke; Oswald, Marlen; Dedeoglu, Fatma; Cantarini, Luca; Benseler, Susanne M

2017-06-01

Cryopyrin-associated periodic syndrome (CAPS) is a rare, heterogeneous disease entity associated with NLRP3 gene mutations and increased interleukin-1 (IL-1) secretion. Early diagnosis and rapid initiation of IL-1 inhibition prevent organ damage. The aim of the study was to develop and validate diagnostic criteria for CAPS. An innovative process was followed including interdisciplinary team building, item generation: review of CAPS registries, systematic literature review, expert surveys, consensus conferences for item refinement, item reduction and weighting using 1000Minds decision software. Resulting CAPS criteria were tested in large cohorts of CAPS cases and controls using correspondence analysis. Diagnostic models were explored using sensitivity analyses. The international team included 16 experts. Systematic literature and registry review identified 33 CAPS-typical items; the consensus conferences reduced these to 14. 1000Minds exercises ranked variables based on importance for the diagnosis. Correspondence analysis determined variables consistently associated with the diagnosis of CAPS using 284 cases and 837 controls. Seven variables were significantly associated with CAPS (pCAPS-typical symptoms: urticaria-like rash, cold-triggered episodes, sensorineural hearing loss, musculoskeletal symptoms, chronic aseptic meningitis and skeletal abnormalities. Sensitivity was 81%, specificity 94%. It performed well for all CAPS subtypes and regardless of NLRP3 mutation. The novel approach integrated traditional methods of evidence synthesis with expert consensus, web-based decision tools and innovative statistical methods and may serve as model for other rare diseases. These criteria will enable a rapid diagnosis for children and adults with CAPS. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Developmental morphology of cover crop species exhibit contrasting behaviour to changes in soil bulk density, revealed by X-ray computed tomography.

Science.gov (United States)

Burr-Hersey, Jasmine E; Mooney, Sacha J; Bengough, A Glyn; Mairhofer, Stefan; Ritz, Karl

2017-01-01

Plant roots growing through soil typically encounter considerable structural heterogeneity, and local variations in soil dry bulk density. The way the in situ architecture of root systems of different species respond to such heterogeneity is poorly understood due to challenges in visualising roots growing in soil. The objective of this study was to visualise and quantify the impact of abrupt changes in soil bulk density on the roots of three cover crop species with contrasting inherent root morphologies, viz. tillage radish (Raphanus sativus), vetch (Vicia sativa) and black oat (Avena strigosa). The species were grown in soil columns containing a two-layer compaction treatment featuring a 1.2 g cm-3 (uncompacted) zone overlaying a 1.4 g cm-3 (compacted) zone. Three-dimensional visualisations of the root architecture were generated via X-ray computed tomography, and an automated root-segmentation imaging algorithm. Three classes of behaviour were manifest as a result of roots encountering the compacted interface, directly related to the species. For radish, there was switch from a single tap-root to multiple perpendicular roots which penetrated the compacted zone, whilst for vetch primary roots were diverted more horizontally with limited lateral growth at less acute angles. Black oat roots penetrated the compacted zone with no apparent deviation. Smaller root volume, surface area and lateral growth were consistently observed in the compacted zone in comparison to the uncompacted zone across all species. The rapid transition in soil bulk density had a large effect on root morphology that differed greatly between species, with major implications for how these cover crops will modify and interact with soil structure.

Enzymatic synthesis of RNAs capped with nucleotide analogues reveals the molecular basis for substrate selectivity of RNA capping enzyme: impacts on RNA metabolism.

Directory of Open Access Journals (Sweden)

Moheshwarnath Issur

Full Text Available RNA cap binding proteins have evolved to specifically bind to the N7-methyl guanosine cap structure found at the 5' ends of eukaryotic mRNAs. The specificity of RNA capping enzymes towards GTP for the synthesis of this structure is therefore crucial for mRNA metabolism. The fact that ribavirin triphosphate was described as a substrate of a viral RNA capping enzyme, raised the possibility that RNAs capped with nucleotide analogues could be generated in cellulo. Owing to the fact that this prospect potentially has wide pharmacological implications, we decided to investigate whether the active site of the model Paramecium bursaria Chlorella virus-1 RNA capping enzyme was flexible enough to accommodate various purine analogues. Using this approach, we identified several key structural determinants at each step of the RNA capping reaction and generated RNAs harboring various different cap analogues. Moreover, we monitored the binding affinity of these novel capped RNAs to the eIF4E protein and evaluated their translational properties in cellulo. Overall, this study establishes a molecular rationale for the specific selection of GTP over other NTPs by RNA capping enzyme It also demonstrates that RNAs can be enzymatically capped with certain purine nucleotide analogs, and it also describes the impacts of modified RNA caps on specific steps involved in mRNA metabolism. For instance, our results indicate that the N7-methyl group of the classical N7-methyl guanosine cap is not always indispensable for binding to eIF4E and subsequently for translation when compensatory modifications are present on the capped residue. Overall, these findings have important implications for our understanding of the molecular determinants involved in both RNA capping and RNA metabolism.

Effect of Lime on characteristics of consolidation, strength, swelling and plasticity of fine grained soil

Science.gov (United States)

Estabragh, A. R.; Bordbar, A. T.; Parsaee, B.; Eskandari, Gh.

2009-04-01

Using Lime as an additive material to clayey soil is one of the best effective technique in building the soil structures to get some purposes such as soil stabilization, soil reinforcement and decreasing soil swelling. In this research the effect of Lime on geotechnical characteristics of a clayey soil was investigated. Soil specimen types used in this study were consisted of clayey soil as the control treatment and clay mixed with different weight fractions of lime, 4, 6, 8 & 10 percent. Some experiments such as CBR, atterburg limits, compaction, consolidation and swelling was conducted on specimens. Results revealed that adding lime to soil would change its physical and mechanical properties. Adding lime increase the compression strength and consolidation coefficient and decrease swelling potential and maximum dry density. According to the results, Atterburg experiments show that presence of lime in soil increase the liquid limit of low plasticity soil and decrease the liquid limit of high plasticity soil, but totally it decreases the plasticity index of soils. Key words: soil stabilization, lime, compression strength, swelling, atterburg limits, compaction

Soil response to skidder trafficking and slash application

Science.gov (United States)

Brian M. Parkhurst; W. Michael Aust; M. Chad Bolding; Scott M. Barrett; Emily A. Carter

2018-01-01

Ground-based timber harvesting systems are common in the United States. Harvesting machinery can negatively influence soils by increasing erosion and decreasing site productivity. Skid trails can become compacted and erosive. Slash applications to skid trails are effective for erosion control, yet few investigations have examined effects of slash on soil physical...

Synthesis of tritium or deuterium labelled 19-nor-3. cap alpha. -hydroxy-5. cap alpha. -androstan-17-one from nortestosterone

Energy Technology Data Exchange (ETDEWEB)

Protiva, J; Klinotova, E [Karlova Univ., Prague (Czechoslovakia). Prirodovedecka Fakulta; Filip, J [Ustav pro Vyzkum, Vyrobu a Vyuziti Radioisotopu, Prague (Czechoslovakia); Hampl, R [Research Inst. of Endocrinology, Praha (Czechoslovakia)

1982-10-20

Tritium and/or deuterium (5-H) labelled 19-nor-3..cap alpha..-hydroxy-5..cap alpha..-androstan-17-one (norandrosterone) was prepared from nortestosterone in view to use it as a radioligand for radioimmunoassay of the main nortestosterone metabolites. Based upon model experiments using testosterone and deuterium labelling, the following four step procedure was established: nortestosterone was oxidized with pyridine chlorochromate and the resulting 19-nor-4-androsten-3,17-dione was tritiated with tritium gas under catalysis with tris(triphenylphosphine)rhodium chloride to give (4,5..cap alpha..-/sup 3/H)19-nor-5..cap alpha..-androstan-3,17-dione. A selective reduction of the latter compound yielded (5-/sup 3/H)19-nor-3..cap alpha..-hydroxy-5..cap alpha..-androstan-17-one of the molar radioactivity 0.3 TBq (8.15 Ci)/mmol.

Plasticity and density-moisture-resistance relations of soils amended with fly ash

Energy Technology Data Exchange (ETDEWEB)

Mapfuno, E.; Chanasyk, D.S. [University of Alberta, Edmonton, AB (Canada). Dept. of Renewable Resources

1998-06-01

The objective of this study was to investigate the impact of fly ash amendments on the plasticity, water retention and penetration resistance-density-moisture relationships of three soils of sandy loam, loam and clay loam textures in order to determine the potential compaction of these soil/fly ash mixtures if they were worked at different moisture ranges. For all three soils the addition of fly ash decreased the plasticity index, but slightly increased the Proctor maximum density. This implies that fly ash amendments reduce the range of moisture within which soils are most susceptible to compaction. However, for the sandy loam and loam textured soils amended with fly ash, cultivation must be avoided at moisture contents close to field capacity since maximum densification occurs at these moisture contents. In all three soils the addition of fly ash increased water retention, especially in the sandy loam. Fly ash amendments increased penetration resistance of the clay loam, but increased penetration resistance of the sandy loam.

SOIL QUALITY AND YIELD OF PINUS TAEDA IN THE PLANALTO CATARINENSE REGION

Directory of Open Access Journals (Sweden)

Cedinara Arruda Santana Morales

2010-12-01

Full Text Available In forest areas, the continual use of the soil alters its physical attributes and deteriorates its quality, in consequence of the traffic of machines used in forest operations, resulting in lower yields of crops. The relationship between soil quality at different sites and the production of Pinus taeda was evaluated in soils of the Planalto Catarinense region. Four farms were used, with two sites on each farm, chosen for the soil type and yield of the forest. The soil morphology was described and samples were collected in each pedogenetic horizon for physical and chemical analyses. Great variation exists in the physical attributes of the profiles, especially in the sequence and thickness of the horizons. Compaction was verified in the surface layer of the shallow profiles, evidenced by the higher bulk density and, or, soil resistance to penetration. In these profiles, the yield was reduced by between 14 and 36%, compared to the deeper profiles with a smaller degree of compaction.

Evaluation of alternative waste management schemes for LWR hulls and caps

International Nuclear Information System (INIS)

Chaudon, L.; Cecille, L.; Klein, M.; Kowa, S.; Mehling, O.; Thiels, G.

1990-01-01

LWR hulls and caps represent one of the major sources of α bearing solid waste generated in the nuclear fuel cycle. For this reason, the CEC launched a theoretical study to evaluate alternative schemes for the overall management of this waste. Both volume reduction techniques and α decontamination of the hulls were assessed. The study demonstrated that the transport and disposal of the conditioned waste in deep geological formations play a dominant part in the total management costs. Important cost savings can be achieved through the implementation of efficient volume reduction techniques, i.e. melting or compaction. As an alternative approach, exhaustive α decontamination of the hulls appears promising, provided that the conditioned waste can be made to comply with the disposal criteria of mines. Finally, prolongation of the interim storage period for the waste packages from 1 to 30 years may prove beneficial on the transport costs

7 CFR 1714.7 - Interest rate cap.

Science.gov (United States)

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false Interest rate cap. 1714.7 Section 1714.7 Agriculture... PRE-LOAN POLICIES AND PROCEDURES FOR INSURED ELECTRIC LOANS General § 1714.7 Interest rate cap. Except... section, or both the rate disparity test for the interest rate cap and the consumer income test set forth...

20 CFR 606.22 - Application for cap.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Application for cap. 606.22 Section 606.22... Reduction § 606.22 Application for cap. (a) Application. (1) The Governor of the State shall make... a State requests a cap on tax credit reduction. The Governor is required to notify the Department on...

Land regeneration: soil development through forestation on former opencast coal-lands in upland Wales

Energy Technology Data Exchange (ETDEWEB)

Haigh, M.J. [Oxford Brookes University, Oxford (United Kingdom)

2001-07-01

The degradation of lands that have been 'reclaimed' after surface coal mining is an international concern. Research near the UNESCO World Heritage site for industrial land at Blaenavon, Wales, seeks more effective ways of creating self-sustaining soils on coal-lands, where the auto-compaction of minespoils causes land degradation. Remedies are sought through the use of close-planted trees as bio-accumulators. Preliminary findings suggest that: 1. forestation quickly mitigates soil compaction, 2. soil fertilisation with NPK improves the survival rate of Alnus glutinosa but may not enhance average growth, 3. soil remineralisation with basic igneous rock flour may be more effective than conventional NPK application alone for enhancing both survival rates and growth and that 4. soil disturbance causes long term depletion of the soil microbial ecosystem. 16 refs., 1 fig., 4 tabs.

IAA transport in corn roots includes the root cap

International Nuclear Information System (INIS)

Hasenstein, K.H.

1989-01-01

In earlier reports we concluded that auxin is the growth regulator that controls gravicurvature in roots and that the redistribution of auxin occurs within the root cap. Since other reports did not detect auxin in the root cap, we attempted to confirm the IAA does move through the cap. Agar blocks containing 3 H-IAA were applied to the cut surface of 5 mm long apical segments of primary roots of corn (mo17xB73). After 30 to 120 min radioactivity (RA) of the cap and root tissue was determined. While segments suspended in water-saturated air accumulated very little RA in the cap, application of 0.5 μ1 of dist. water to the cap (=controls) increased RA of the cap dramatically. Application to the cap of 0.5 μ1 of sorbitol or the Ca 2+ chelator EGTA reduced cap RA to 46% and 70% respectively compared to water, without affecting uptake. Control root segments gravireacted faster than non-treated or osmoticum or EGTA treated segments. The data indicate that both the degree of hydration and calcium control the amount of auxin moving through the cap

Remediation techniques for heavy metal-contaminated soils: Principles and applicability.

Science.gov (United States)

Liu, Lianwen; Li, Wei; Song, Weiping; Guo, Mingxin

2018-08-15

Globally there are over 20millionha of land contaminated by the heavy metal(loid)s As, Cd, Cr, Hg, Pb, Co, Cu, Ni, Zn, and Se, with the present soil concentrations higher than the geo-baseline or regulatory levels. In-situ and ex-situ remediation techniques have been developed to rectify the heavy metal-contaminated sites, including surface capping, encapsulation, landfilling, soil flushing, soil washing, electrokinetic extraction, stabilization, solidification, vitrification, phytoremediation, and bioremediation. These remediation techniques employ containment, extraction/removal, and immobilization mechanisms to reduce the contamination effects through physical, chemical, biological, electrical, and thermal remedy processes. These techniques demonstrate specific advantages, disadvantages, and applicability. In general, in-situ soil remediation is more cost-effective than ex-situ treatment, and contaminant removal/extraction is more favorable than immobilization and containment. Among the available soil remediation techniques, electrokinetic extraction, chemical stabilization, and phytoremediation are at the development stage, while the others have been practiced at full, field scales. Comprehensive assessment indicates that chemical stabilization serves as a temporary soil remediation technique, phytoremediation needs improvement in efficiency, surface capping and landfilling are applicable to small, serious-contamination sites, while solidification and vitrification are the last remediation option. The cost and duration of soil remediation are technique-dependent and site-specific, up to $500ton -1 soil (or $1500m -3 soil or $100m -2 land) and 15years. Treatability studies are crucial to selecting feasible techniques for a soil remediation project, with considerations of the type and degree of contamination, remediation goals, site characteristics, cost effectiveness, implementation time, and public acceptability. Copyright © 2018 Elsevier B.V. All rights

Improvements of soil quality for increased food production in Norway

Science.gov (United States)

Øygarden, Lillian; Klakegg, Ove; Børresen, Trond; Krogstad, Tore; Kjersti Uhlen, Anne

2016-04-01

Since the 1990ties, agricultural land in use in Norway has diminished and yields per hectare for cereals and forages have stagnated. An expert panel appointed to advice on how to increase Norwegian grain production emphasizes low profitability and poor soil quality as limiting factors. A White Paper from the Norwegian Government, Report No.9 (2011-2012), stated that the main goal for the agricultural sector is to increase food production proportional to the expected increase in population (20 % by 2030) in order to maintain self-sufficiency at the present level. This is the background for the interdisciplinary project AGROPRO "Agronomy for increased food production - Challenges and solutions" (2013 - 2017)" financed by the Norwegian research council. A mail goal is seeking possibilities for improvements in agronomic practices for increased and sustainable food production and to identify drivers and challenges for their implementation. Are the key to higher yields hidden in the soil? The paper present an overview of the research activities in the project and some results of the improvements of soil quality to minimize yield gap in cereal and forage production. Detailed new soil maps provide soil information on field scale of soil quality and the suitability for growing different crops like cereal production or vegetables. The detailed soil information is also beeing used for development and adaptation of the planning tool «Terranimo» to reduce risk of soil compaction.The farmer get available soil information for each field, provide information about the maschinery in use- tractors and equipment, tyres, pressure. The decision tool evaluate when the soil is suitable for tillage, calculate the risk of compaction for dry, moist and wet soil. New research data for compaction on Norwegian clay and silt soil are included. Climate change with wetter conditions gives challenges for growing cereals. The project is testing genetic variation in cereals for tolerance to water

Relations between Agronomic Practice and Earthworms in Norwegian Arable Soils

OpenAIRE

Pommeresche, Reidun; Løes, Anne-Kristin

2009-01-01

This paper presents Norwegian studies of earthworms (density, biomass, burrows density, species, juvenile to adult ratios) in arable soil in Norway conducted during the last 20 years. The effects of crop rotations, fertilization, soil tillage and compaction on earthworms are presented, based on various field experiments. Geophagous (soil eating) species such as Aporrectodea caliginosa and A. rosea dominate the earthworm fauna in Norwegian arable soil. Lumbricus terrestris is also present; in ...

Compaction-Based Deformable Terrain Model as an Interface for Real-Time Vehicle Dynamics Simulations

Science.gov (United States)

2013-04-16

N.Y. [20] Wulfsohn, D., and Upadhyaya, S. K., 1992, "Prediction of traction and soil compaction using three-dimensional soil- tyre contact profile," Journal of Terramechanics, 29(6), pp. 541-564. ...the relative speedup of utilizing GPUs for computational acceleration. INTRODUCTION In order to enable off- road vehicle dynamics analysis...ANSI Std Z39-18 Page 2 of 8 Figure 2. Tire geometry used to determine collision points with the terrain In the context of off- road vehicle

Preparation of Sandy Soil Stabilizer for Roads Based on Radiation Modified Polymer Composite

International Nuclear Information System (INIS)

Elnahas, H.H.

2016-01-01

Radiation modified polymer composite (RMPC) was studied to build an extremely durable sandy road, construct a trail or bath, or control dust and erosion. A dilute solution of composite binds sandy soil fines through a coagulation bonding process. The result is a dense soil structure that has superior resistance to cracks and water penetration and can also solve erosion control problems. In erosion control applications, diluted composite is merely sprayed into sandy soil without compaction, effectively sealing the surface to prevent air-born dust or deterioration from erosion. The prepared composite has an elastic and melt-able film formation that imparts thermal compacting to the stabilized sandy soil after full dryness for sandy road leveling, repairing and restoration processes. The prepared composite is environmentally economical when compared with traditional sandy soil stabilizing (SSS) or sealing methods.

Increased 5. cap alpha. -reductase activity in idiopathic hirsutism

Energy Technology Data Exchange (ETDEWEB)

Serafini, P.; Lobo, R.A.

1985-01-01

In vitro, genital skin 5..cap alpha..-reductase activity (5..cap alpha..-RA) was measured in ten hirsute women with normal androgen levels (idiopathic hirsutism (IH)) and in ten hirsute women with elevated androgen levels (polycystic ovary syndrome (PCO)) in order to determine the influence of secreted androgens on 5..cap alpha..-RA. In vitro 5..cap alpha..-RA was assessed by incubations of skin with /sup 14/C-testosterone (T) for 2 hours, after which steroids were separated and the radioactivity of dihydrotestosterone (DHT) and 5..cap alpha..-androstane 3..cap alpha..-17..beta..-estradiol (3..cap alpha..-diol) in specific eluates were determined. All androgens were normal in IH with the exception of higher levels of 3..cap alpha..-diol glucuronide which were similar to the levels of PCO. The conversion ratio (CR) of T to DHT in IH and PCO were similar, yet significantly greater than the CR of control subjects. The CR of T to 3..cap alpha..-diol in IH and PCO were similar, yet higher than in control subjects. Serum androgens showed no correlation with 5..cap alpha..-RA, while the CR of T to DHT showed a significant positive correlation with the Ferriman and Gallwey score. The increased 5..cap alpha..-RA in IH appears to be independent of serum androgen levels and is, therefore, an inherent abnormality. The term idiopathic is a misnomer, because hirsutism in these patients may be explained on the basis of increased skin 5..cap alpha..-RA.

Mouse Embryo Compaction.

Science.gov (United States)

White, M D; Bissiere, S; Alvarez, Y D; Plachta, N

2016-01-01

Compaction is a critical first morphological event in the preimplantation development of the mammalian embryo. Characterized by the transformation of the embryo from a loose cluster of spherical cells into a tightly packed mass, compaction is a key step in the establishment of the first tissue-like structures of the embryo. Although early investigation of the mechanisms driving compaction implicated changes in cell-cell adhesion, recent work has identified essential roles for cortical tension and a compaction-specific class of filopodia. During the transition from 8 to 16 cells, as the embryo is compacting, it must also make fundamental decisions regarding cell position, polarity, and fate. Understanding how these and other processes are integrated with compaction requires further investigation. Emerging imaging-based techniques that enable quantitative analysis from the level of cell-cell interactions down to the level of individual regulatory molecules will provide a greater understanding of how compaction shapes the early mammalian embryo. © 2016 Elsevier Inc. All rights reserved.

Compaction and rotovation effects on soil pore characteristics of a loamy sand soil with contrasting organic matter content

DEFF Research Database (Denmark)

Eden, Marie; Schjønning, Per; Møldrup, Per

2011-01-01

only mineral fertilizer (MF) or, in addition, animal manure (OF). Undisturbed soil cores were taken from two separate fields in consecutive years at an identical stage in the crop rotation. We measured soil organic carbon (OC), soil microbial biomass carbon (BC), and hot-water extractable carbon (Chot...... OF had larger porosity than that from treatment MF. Treatment P eliminated this difference and significantly reduced the volume of macropores. This interaction between soil organic matter content and mechanical impact was also reflected in the gas diffusion data. Specific air permeability was mainly...

Mercury transfer from soil to olive trees. A comparison of three different contaminated sites.

Science.gov (United States)

Higueras, Pablo L; Amorós, José Á; Esbrí, José Maria; Pérez-de-los-Reyes, Caridad; López-Berdonces, Miguel A; García-Navarro, Francisco J

2016-04-01

Mercury contents in soil and olive tree leaves have been studied in 69 plots around three different source areas of this element in Spain: Almadén (Ciudad Real), Flix (Tarragona) and Jódar (Jaén). Almadén was the world's largest cinnabar (HgS) mining district and was active until 2003, Flix is the oldest Spanish chlor-alkali plant (CAP) and has been active from 1898 to the present day and Jódar is a decommissioned CAP that was active for 14 years (1977-1991). Total mercury contents have been measured by high-frequency modulation atomic absorption spectrometry with Zeeman effect (ZAAS-HFM) in the soils and olive tree leaves from the three studied areas. The average soil contents range from 182 μg kg(-1) in Flix to 23,488 μg kg(-1) in Almadén, while the average leaf content ranges from 161 μg kg(-1) in Jódar to 1213 μg kg(-1) in Almadén. Despite the wide range of data, a relationship between soil-leaf contents has been identified: in Almadén and Jódar, multiplicative (bilogarithmic) models show significant correlations (R = 0.769 and R = 0.484, respectively). Significant correlations were not identified between soil and leaf contents in Flix. The continuous activity of the Flix CAP, which remains open today, can explain the different uptake patterns for mercury, which is mainly atmospheric in origin, in comparison to the other two sites, where activity ceased more than 10 years ago and only soil uptake patterns based on the Michaelis-Menten enzymatic model curve are observed.

The influence of sand content on swelling pressures and structure developed in statically compacted Na-bentonite

International Nuclear Information System (INIS)

Gray, M.N.; Cheung, S.C.H.; Dixon, D.A.

1984-09-01

A laboratory investigation of the vertical and lateral swelling pressures developed in statically compacted, air-dry specimens of sodium (Na)-bentonite:silica sand mixtures as they are saturated in confined conditions with double-distilled, deionized water is described. The results are interpreted with the aid of observations of the compacted soil structures made in a scanning electron microscope. It is shown that the sand acts as an inert filler material and vertical swelling pressures are controlled by a parameter termed the effective clay dry density (qsub(c)). A limiting value of qsub(c) exists below which vertical and lateral swelling pressures do not differ and are theoretically predictable. Above this value, vertical pressures exceed lateral ones. This is related to a change from an isotropic to an anisotropic soil fabric as qsub(c) is increased above the limiting value

Soil aggregation and slope stability related to soil density, root length, and mycorrhiza

Science.gov (United States)

Graf, Frank; Frei, Martin

2013-04-01

Eco-engineering measures combine the use of living plants and inert mechanical constructions to protect slopes against erosion and shallow mass movement. Whereas in geotechnical engineering several performance standards and guidelines for structural safety and serviceability of construction exist, there is a lack of comparable tools in the field of ecological restoration. Various indicators have been proposed, including the fractal dimension of soil particle size distribution, microbiological parameters, and soil aggregate stability. We present results of an soil aggregate stability investigation and compare them with literature data of the angle of internal friction ?' which is conventionally used in slope stability analysis and soil failure calculation. Aggregate stability tests were performed with samples of differently treated moraine, including soil at low (~15.5 kN/m³) and high (~19.0 kN/m³) dry unit weight, soil planted with Alnus incana (White Alder) as well as the combination of soil planted with alder and inoculated with the mycorrhizal fungus Melanogaster variegatus s.l. After a 20 weeks growth period in a greenhouse, a total of 100 samples was tested and evaluated. Positive correlations were found between the soil aggregate stability and the three variables dry unit weight, root length per soil volume, and degree of mycorrhization. Based on robust statistics it turned out that dry unit weight and mycorrhization degree were strongest correlated with soil aggregate stability. Compared to the non-inoculated control plants, mycorrhized White Alder produced significantly more roots and higher soil aggregate stability. Furthermore, the combined biological effect of plant roots and mycorrhizal mycelia on aggregate stability on soil with low density (~15.5 kN/m³) was comparable to the compaction effect of the pure soil from 15.5 to ~19.0 kN/m³. Literature data on the effect of vegetation on the angle of internal friction ?' of the same moraine showed