WorldWideScience

Sample records for caps compacted soil

  1. Natural physical and biological processes compromise the long-term performance of compacted soil caps

    International Nuclear Information System (INIS)

    Compacted soil barriers are components of essentially all caps placed on closed waste disposal sites. The intended functions of soil barriers in waste facility caps include restricting infiltration of water and release of gases and vapors, either independently or in combination with synthetic membrane barriers, and protecting other manmade or natural barrier components. Review of the performance of installed soil barriers and of natural processes affecting their performance indicates that compacted soil caps may function effectively for relatively short periods (years to decades), but natural physical and biological processes can be expected to cause them to fail in the long term (decades to centuries). This paper addresses natural physical and biological processes that compromise the performance of compacted soil caps and suggests measures that may reduce the adverse consequences of these natural failure mechanisms

  2. Soil compaction in forest soils

    OpenAIRE

    TURGUT, Bülent

    2012-01-01

    Soil compaction is a widespread degradation process in forest sites. Soil degradation occurring on the structural formation of a natural soil system by rainfall or mechanical outer forces generally results in soil particles to be rearranged tighter than its previous status. In this case, soil compaction -defined as the increase in bulk density of soil- develops with negative effects on soil-plant-water relations. With the compaction, the density of soil increases while the porosity rate decre...

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

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, S. [IGB - Ingenieurbuero fuer Grundbau, Hamburg (Germany)

    1997-12-31

    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{sup 2} to 500 m{sup 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{sup -10} m{sup 3} m{sup -2} s{sup -1} to 4 x 10{sup -8} m{sup 3} m{sup -2} s{sup -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.

  4. Compaction properties of agricultural soils

    OpenAIRE

    TANG, Anh Minh; CUI, Yu Jun; Eslami, Javad; DEFOSSEZ BERTHOUD, Pauline

    2007-01-01

    The compaction of field soils due to repeated rolling of agricultural vehicles is one of the main reasons for the agricultural soil degradation. A good understanding of the compaction properties of these soils is essential for an optimum organisation of agricultural activities, and therefore for environmental protection in terms of nitrate migrations. In the present work, the compaction properties of agricultural soils from four sites in France are studied after experimental data ...

  5. Soil compaction and soil tillage - studies in agricultural soil mechanics

    OpenAIRE

    Keller, Thomas

    2004-01-01

    This thesis deals with various aspects of soil compaction due to agricultural field traffic, the draught force requirement of tillage implements and soil structures produced by tillage. Several field experiments were carried out to study the mechanical impact of agricultural machines. It was shown that the stress interaction from the different wheels in dual and tandem wheel configurations is small and these wheels can be considered separate wheels with regard to soil stress. Hence, soil stre...

  6. Soil compaction and fertilization in soybean productivity

    Directory of Open Access Journals (Sweden)

    Beutler Amauri Nelson

    2004-01-01

    Full Text Available Soil compaction and fertilization affect soybean development. This study evaluated the effects of soil compaction and fertilization on soybean (Glycine max cv. Embrapa 48 productivity in a Typic Haplustox under field conditions in Jaboticabal, SP, Brazil. A completely randomized design with a 5 x 2 factorial layout (compaction vs. fertilization, with four replications in each treatment, was employed. Each experimental unit (replicate consisted of a 3.6 m² useful area. After the soil was prepared by cultivation, an 11 Mg tractor passed over it a variable number of times to create five levels of compaction. Treatments were: T0= no compaction, T1= one tractor pass, T2= two, T4= four, and T6= six passes, and no fertilizer and fertilizer to give soybean yields of 2.5 to 2.9 Mg ha-1. Soil was sampled at depths of 0.02-0.05, 0.07-0.10, and 0.15-0.18 m to determine macro and microporosity, penetration resistance (PR, and bulk density (Db. After 120 days growing under these conditions, the plants were analyzed in terms of development (plant height, number of pods, shoot dry matter per plant and weight of 100 seeds and seed productivity per hectare. Soil compaction decreased soybean development and productivity, but this effect was decreased by soil fertilization, showing that such fertilization increased soybean tolerance to soil compaction.

  7. Mechanical behaviour of compacted decomposed granite soil

    OpenAIRE

    Lee, I K

    1991-01-01

    The purpose of this research was to determine the mechanical behaviour of decomposed granite soil, especially when it is used as a construction material. The soil tested was a completely weathered granite soil (grade V) taken from Seoul, Korea and was a well graded silty sand and gravel. Triaxial compression tests have been carried out on compacted samples and special attention has been given to the determination of the effects of the moisture condition on the behaviour. The test results show...

  8. Deep Compaction Control of Sandy Soils

    Directory of Open Access Journals (Sweden)

    Bałachowski Lech

    2015-02-01

    Full Text Available Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

  9. Soil compaction: Evaluation of stress transmission and resulting soil structure

    DEFF Research Database (Denmark)

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

    , 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......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...

  10. Neutron computerized tomography in compacted soil

    International Nuclear Information System (INIS)

    This work applies the computerized tomography technique using thermal neutron beams for inspection of compacted soil specimens. Several specimens were analysed whose bulk densities vary from 1.61 up to 1.93 g·cm-3 and the water content from 7.8 up to 14.8%. The images reconstructed with thermal neutrons are compared with the reconstruction obtained with gamma rays of 316 keV, to demonstrate the sensitivity of the neutron technique. By analysing the reconstructed images it is possible to detect the different water content levels and to identify the soil composition. The macroscopic total cross-section values and the compactation curves obtained using the tomographic images agree with the expected data

  11. Influence of Soil Type and Placement Conditions on Soil Suction in Compacted Expansive Soils

    OpenAIRE

    Zein, Abdul Karim Mohammad

    2009-01-01

    This study investigates the influence of the type of soil, compaction moisture content and dry density on soil suction in impact compacted expansive soils. Many samples which were obtained from five highly expansive soil types were tested. The soil types considered in this study included two natural from Sudan and three natural/artificial soil mixtures. An apparatus based on the axis-translation technique of suction measurement was developed and successfully used for laboratory...

  12. Influence of a compacted subsurface layer on soil erosion

    International Nuclear Information System (INIS)

    It has been recognized that water erosion of soil and soil compaction are among the major soil degradation processes in Europe. Little is known about the relationships between soil compaction and the soil erosion processes. Effect of rainfall on soil erosion, i.e. the rainfall erosivity has been related logarithmically to rainfall intensity. Texture, structure, water permeability and humus content are the soil properties, which have been considered as most important for evaluating the effect of soil on water erosion rates. I will discuss a mathematical model developed for estimating the influence of compacted subsurface layer formed below a shallow tillage layer on soil erosion. The mathematical model is developed on the basis of data from field experiments with simulated rainfalls of intensities from 18 to 120 mm h-1 to study the influence of compacted subsurface layer caused by continuous shallow tillage on the soil erosion processes on Haplic Kastanozem. A soil with a compacted subsurface layer can be represented conceptually as a media consisting of two layers - tilled layer TL and compacted layer CL which differ in their physical properties, such as bulk density BD and water retention W. The model shows good capability of predicting the soil erosion characteristics depending on the degree of compaction and the rainfall intensity. The estimates of E0, SL and SLnet, predicted by the model for three levels of the index of soil water distribution and four levels of the rainfall intensity, demonstrate the basic trends of soil erosion behaviour under conditions of a compacted subsurface layer. It is established that the type of the relationships between the soil erosion characteristics and the degree of compaction depends considerably on the index of soil water distribution. Generally, a compacted subsurface layer affects soil erosion much more significantly when the water content is higher in TL than in CL. Verification of the model is needed for still broader

  13. Computed tomography scanner applied to soil compaction studies

    International Nuclear Information System (INIS)

    The soil compaction problem was studied using a first generation computed tomography scanner (CT). This apparatus gets images of soil cross sections samples, with resolution of a few millimeters. We performed the following laboratory and field experiments: basic experiments of equipment calibrations and resolutions studies; measurements of compacted soil thin layers; measurements of soil compaction caused by agricultural tools; stress-strain modelling in confined soil sample, with several moisture degree; characterizations of soil bulk density profile with samples collected in a hole (trench), comparing with a cone penetrometer technique. (author)

  14. Soil compaction and structural morphology under tractor wheelings

    Science.gov (United States)

    Shanahan, Peter; Quinton, John; Binley, Andrew; Silgram, Martyn

    2010-05-01

    Compaction of cultivated soils is a major problem for agriculture in terms of yield decline and sustainable soil resource management. Tramline wheelings exacerbate runoff and increase erosion from arable land. The UK Department for Environment, Food and Rural Affairs (Defra) LINK Project - a joint venture between agri-business, land managers and research groups - is currently evaluating a number of methods for alleviating compaction in tractor wheelings across a range of soil types in England. Using innovative applications of agri-geophysics (e.g. ground penetrating radar, electrical resistivity, acoustics and x-ray tomography), this current project aims to determine relationships between properties derived from geophysical methods (e.g. soil moisture, porosity), soil compaction and structural morphology. Such relationships are important for a clearer understanding of hydrological and biogeochemical processes in compacted soils, to address land management practices and develop cost-effective mitigation measures. Our poster will present some early results of this study.

  15. Analysis of the Blasting Compaction on Gravel Soil

    OpenAIRE

    Qingwen Li; Yuan Li; Gautam Dasgupta; Dongping Song; Lan Qiao; Liping Wang; Jianghui Dong

    2015-01-01

    The settlement control is critical for the safety of road based on high filled embankment. The traditional construction methods have the characteristic with less soil thickness compacted at a time. There are many advantages to compact the gravel soil with blasting. The cavity in soil is formed by blasting and its fillings to form a composite foundation for the embankment. The field data show this composite foundation can meet the requirement of loading and settlement control with less constru...

  16. The impact of soil compaction on runoff - a meta analysis

    Science.gov (United States)

    Rogger, Magdalena; Blöschl, Günter

    2016-04-01

    Soil compaction caused by intensive agricultural practices is known to influence runoff processes at the local scale and is often speculated to have an impact on flood events at much larger scales. Due to the complex and diverse mechanisms related to soil compaction, the key processes influencing runoff at different scales are still poorly understood. The impacts of soil compaction are, however, not only investigated by hydrologists, but also by agricultural scientists since changes in the soil structure and water availability have a direct impact on agricultural yield. Results from these studies are also of interest to hydrologists. This study presents a meta analysis of such agricultural studies with the aim to analyse and bring together the results related to runoff processes. The study identifies the most important parameters used to describe soil compaction effects and compares the observed impacts under different climatic and soil conditions. The specific type of agricultural practice causing the soil compaction is also taken into account. In a further step the results of this study shall be used to derive a toy model for scenario analysis in order to identify the potential impacts of soil compaction on runoff processes at larger scales then the plot scale.

  17. 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

  18. 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

  19. Effects of soil moisture content and tractor wheeling intensity on traffic-induced soil compaction

    OpenAIRE

    AHMADI, Iman; GHAUR, Hossein

    2015-01-01

    Soil compaction causes deleterious effects on physical and mechanical proprieties of agricultural soils. In order to investigate the effect of soil moisture content and tractor wheeling intensity on traffic-induced soil compaction, this study was carried out on a field with clay loam soil. Soil dry bulk density and hydraulic conductivity as well as emergence percentage of corn seedlings and dry mass of the sampled mature plants were considered the dependent variables of the experiment. Ind...

  20. Compaction interpreted in the framework of unsaturated soil mechanics

    OpenAIRE

    Caicedo, Bernardo; LEROUEIL, Serge; Thorel, Luc; TRISTANCHO, Julian

    2015-01-01

    Compacted materials are fundamentally unsaturated soils whose behaviour can be expansive or collapsible depending upon changes in water content or stresses. Their behaviour is strongly dependent on matric suction, water content, and stress history. This paper presents a methodology for investigating the stress/strain, and suction/water content paths during one dimensional compaction of unsaturated soils. It focuses on anisotropic behaviour. The testing program was carried out in an automated ...

  1. Estimation of CI-based soil compaction status from soil apparent electrical conductivity

    Science.gov (United States)

    Regionalization of soil properties is very important for successful site-specific field management. Soil compaction is a critical issue to be detected and managed due to its effects on crop growth. Soil compaction has been conventionally quantified as cone index (CI) measured by an ASABE-standard co...

  2. Effect of gravel on hydraulic conductivity of compacted soil liners

    International Nuclear Information System (INIS)

    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%

  3. Experimental study of soil compaction effects on GPR signals

    Science.gov (United States)

    Wang, Ping; Hu, Zhenqi; Zhao, Yanling; Li, Xinju

    2016-03-01

    Mechanical operations may lead to soil compaction hazard in land consolidation projects. Aiming to quantitatively guarantee soil compaction status with ground penetrating radar (GPR), we should clearly understand the relationship between bulk density/penetration resistance (PR) and GPR signals. This research adopted GPR with a central frequency of 500 MHz and the experimental design with laboratory test and outdoor test. Because soil dielectric constant receives combination influence of soil properties, statistical methods were used to analyze the influence of soil bulk density on electromagnetic wave velocity. Significant correlation exists between electromagnetic wave velocity and bulk density, with a partial correlation coefficient of 0.882 and two-tailed significance of 0.020. While soil dielectric constant strongly depends on soil water content, the growing of soil bulk density usually reduces free water content, increases bound water content and finally influences GPR signals. The results also showed that high soil PR value accompanied with low amplitude values of electromagnetic wave and fast decay rate of the amplitude back to noise level. More experimental data would be acquired for accurate quantification between soil compaction and GPR signals with statistic methods in the future research.

  4. Soil Compaction and Oil Palm (Elaeis guineensis Yield in a Clay Textured Soil

    Directory of Open Access Journals (Sweden)

    Zuraidah Yahya

    2010-01-01

    Full Text Available Problem statement: The impacts of soil compaction on crop yields have been studied extensively by soil scientists due to declining soil productivity associated with mechanisation. However, a relationship between machine-induced soil compaction and oil palm (Elaeis guineensis yield is unclear. Therefore, the objectives of this study were to determine the effects of mechanization on soil physical properties and the influence on oil palm yield. Approach: The palms were planted in Bernam series soil which is clay textured. Compaction treatments were imposed for 6 consecutive years. Comparisons were made between the effects of soil compaction caused by different trailer weights and monthly transportation frequency. Results: The results showed a beneficial effect of soil compaction on the oil palm yield. It significantly increased the yield with increased mean soil bulk density. The transportation frequency played a greater role than the trailer weight. After six years of soil compaction, there was a positive relationship between mean soil bulk density, porosity and oil palm yield. Conclusion: Thus compaction may not often be a problem.

  5. 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

  6. The influence of skidding operations on forest soil properties and soil compaction in Bartin, Turkey.

    OpenAIRE

    BOLAT, İlyas; MELEMEZ, Kenan; Özer, Davut

    2015-01-01

    Mechanized harvesting operations yield high productivity; however, it damages forest soils seriously. The objective of this study is to determine the impacts of skidding operations ontopsoil physical and chemical properties at four different forest floors (tractor road, skid trail, harvesting area and undisturbed area) after a harvesting season. Also, the relationship between soil compaction and soil moisture of these areas were analysed. Soil compaction was estimated with the values of topso...

  7. Soil compaction in vineyards of different ages in Pannonian Croatia. Part I. Influence of machinery traffic and soil management on compaction of individual horizons

    OpenAIRE

    Igor BOGUNOVIĆ; Ivica KISIĆ; Maletić, Edi; PERČIN, Aleksandra; MATOŠIĆ, Stefan; Luka ROŠKAR

    2016-01-01

    Soil compaction is one of the most important problems in agricultural production. Tillage system with frequent machinery traffic due protection, agrotechnic operation and harvesting has effect on different soil compaction levels in the vineyards. The aim of this study was to determine and compare the soil resistance, soil bulk density and soil moisture within and between rows in the seven-year and thirty-year vineyard due to tillage and compacting by machinery traffic. Results show statistica...

  8. Tillage and farmyard manure efects on crusting and compacting soils at Katumani, Semi-arid Kenya

    NARCIS (Netherlands)

    Biamah, E.K.; Sterk, G.; Stroosnijder, L.

    2008-01-01

    In semi-arid Kenya, the most dominatn soil types are of limited agricultural productivity due to crusting and compaction. The occurence of soil crusting and compaction is attributed to seasonal rainfall characteristics, physical soil properties and bad tillage practices. Soil crusting and compaction

  9. Compton scattering tomography in soil compaction study

    Science.gov (United States)

    Balogun, F. A.; Cruvinel, P. E.

    2003-06-01

    Compton scattering imaging technique is investigated as a possible tool in soil density distribution mapping for agricultural purposes. In Compton scattering tomography, the number of photons that had been inelastically scattered from a well-defined volume of a sample is employed as a non-destructive technique to display soil density distribution. Images are also shown, of soil samples, at two closely related densities. Good contrast is recorded between the various inserts and their host matrix. Line scans through the images showed good contrast resolution, shape and edge definition. Spatial resolution could be enhanced by the use of a focussing collimator on the detector. This will also serve to increase the solid angle subtended at the detector by the scattering volume, with a possible reduction in counting time at the same precision level.

  10. Analysis of the Blasting Compaction on Gravel Soil

    Directory of Open Access Journals (Sweden)

    Qingwen Li

    2015-01-01

    Full Text Available The settlement control is critical for the safety of road based on high filled embankment. The traditional construction methods have the characteristic with less soil thickness compacted at a time. There are many advantages to compact the gravel soil with blasting. The cavity in soil is formed by blasting and its fillings to form a composite foundation for the embankment. The field data show this composite foundation can meet the requirement of loading and settlement control with less construction time. In geotechnical blasting, the high temperature due to blasting will swell the material around, so its worthy to do the coupled analysis with thermal mechanics (TM and blasting compaction in the high filled embankment. In this paper, a 3D model is built with FLAC3D to simulate a single hole to predict the range and degree of thermal propagation. Then, the thermal strains got from the model are used to estimate the displacement of surrounding soil to predict the degree of compaction and optimize the distribution of blast holes in plan.

  11. Challenges in the development of analytical soil compaction models

    DEFF Research Database (Denmark)

    Keller, Thomas; Lamandé, Mathieu

    2010-01-01

    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...... transducers and therefore of stress measurements is not well known, despite numerous studies on stress in the soil profile below agricultural tyres. Although arable soils are characterised by distinct soil layers with different mechanical properties, analytical models rely on a one-layer approach with regard......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...

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  14. 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......, no statistical difference in total N losses and 15N-(N2O+N2) flux between the uncompacted soil and the compacted soil was detected. Compaction promoted soil denitrification and may impact urban N biogeochemical cycling. © 2013 Springer-Verlag Berlin Heidelberg....

  15. Effects of soil compaction and organic carbon content on preferential flow in loamy field soils

    DEFF Research Database (Denmark)

    Soares, Antonio; Møldrup, Per; Vendelboe, Anders Lindblad;

    2015-01-01

    © 2015 Wolters Kluwer Health, Inc. Preferential flowand transport throughmacropores affect plant water use efficiency and enhance leaching of agrochemicals and the transport of colloids, thereby increasing the risk for contamination of groundwater resources. The effects of soil compaction...

  16. Resistance and resilience of the forest soil microbiome to logging-associated compaction

    OpenAIRE

    Hartmann, Martin; Niklaus, Pascal A; Zimmermann, Stephan; SCHMUTZ Stefan; Kremer, Johann; Abarenkov, Kessy; Lüscher, Peter; Widmer, Franco; Frey, Beat

    2013-01-01

    Soil compaction is a major disturbance associated with logging, but we lack a fundamental understanding of how this affects the soil microbiome. We assessed the structural resistance and resilience of the microbiome using a high-throughput pyrosequencing approach in differently compacted soils at two forest sites and correlated these findings with changes in soil physical properties and functions. Alterations in soil porosity after compaction strongly limited the air and water conductivity. C...

  17. Comparisons of different procedures of pre-compaction stress determination on weakly structured soils

    NARCIS (Netherlands)

    Mosaddeghi, M.R.; Koolen, A.J.; Hemmat, A.; Hajabbasi, M.A.; Lerink, P.

    2007-01-01

    Compaction is an important component of soil degradation. In this regard, the pre-compaction stress (sigma(pc)) concept is considered useful in mechanized agriculture nowadays. When the external forces exceed the internal strength (sigma(pc)) of soil, soil structure and soil physical quality will de

  18. THE EFFECT OF MIXING WITH ORGANIC SOIL ON CHANGES IN SOME PHYSICAL PROPERTIES OF A COMPACTED CLAY LOAM SOIL

    OpenAIRE

    Abdullah BARAN; BENDER, Damla; ÖZKAN, İlhami

    1996-01-01

    In this research, the effect of organic soil on changes in total pore space, aeration porosity, available water content and hydraulic conductivity of a compacted clay loam were investigated. By adding organic soil at rates of 0 %, 1 %, 2 % and 4 % to soil, mixtures were compacted at compaction levels of 0 kg/cm2, 0.21 kg/cm2, 1.98 kg/cm2 and 3.95 kg/cm2 Some physical properties of compacted soil were determined. Compaction decreased total pore space, areation porosity, available water content...

  19. 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 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...... 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...

  20. Computation of Blast Pressures foam Propellant for Compaction of Soil

    Directory of Open Access Journals (Sweden)

    K. B. Agarwal

    1974-01-01

    Full Text Available The knowledge of blast pressure characteristics is a pre-requisite for a suitable application of foam propellant to emergency military construction such as compacting of the soil from an aircraft using the foam propellant. The foam propellant considered here is a combination of hydrazine and ammonium perchlorate. The blast pressure is found to be a function of the quantity of foam propellant used and the distance of the observation point. This paper attempts to compute the blast pressure versus time characteristics of a foam propellant strip.

  1. Resistance and resilience of the forest soil microbiome to logging-associated compaction.

    Science.gov (United States)

    Hartmann, Martin; Niklaus, Pascal A; Zimmermann, Stephan; Schmutz, Stefan; Kremer, Johann; Abarenkov, Kessy; Lüscher, Peter; Widmer, Franco; Frey, Beat

    2014-01-01

    Soil compaction is a major disturbance associated with logging, but we lack a fundamental understanding of how this affects the soil microbiome. We assessed the structural resistance and resilience of the microbiome using a high-throughput pyrosequencing approach in differently compacted soils at two forest sites and correlated these findings with changes in soil physical properties and functions. Alterations in soil porosity after compaction strongly limited the air and water conductivity. Compaction significantly reduced abundance, increased diversity, and persistently altered the structure of the microbiota. Fungi were less resistant and resilient than bacteria; clayey soils were less resistant and resilient than sandy soils. The strongest effects were observed in soils with unfavorable moisture conditions, where air and water conductivities dropped well below 10% of their initial value. Maximum impact was observed around 6-12 months after compaction, and microbial communities showed resilience in lightly but not in severely compacted soils 4 years post disturbance. Bacteria capable of anaerobic respiration, including sulfate, sulfur, and metal reducers of the Proteobacteria and Firmicutes, were significantly associated with compacted soils. Compaction detrimentally affected ectomycorrhizal species, whereas saprobic and parasitic fungi proportionally increased in compacted soils. Structural shifts in the microbiota were accompanied by significant changes in soil processes, resulting in reduced carbon dioxide, and increased methane and nitrous oxide emissions from compacted soils. This study demonstrates that physical soil disturbance during logging induces profound and long-lasting changes in the soil microbiome and associated soil functions, raising awareness regarding sustainable management of economically driven logging operations. PMID:24030594

  2. The impact of soil compaction and freezing-thawing cycles on soil structure and yield in Mollisol region of China

    Science.gov (United States)

    Wang, Enheng; Zhao, Yusen; Chen, Xiangwei

    2015-04-01

    Agricultural machinery tillage and alternating freezing and thawing are two critical factors associated with soil structure change and accelerates soil erosion in the black soil region of Northeast China. Combining practical machinery operation and natural freeze-thaw cycles with artificial machinery compaction in the field and artificial freeze-thaw cycles in the lab, the plus and minus benefits of machinery tillage, characterization of seasonal freeze-thaw cycles, and their effects on soil structure and yield were studied. Firstly,the effects of machinery type and antecedent water content on soil structure and soil available nutrient were investigated by measuring soil bulk density, soil strength, soil porosity, soil aggregate distribution and stability, and three soil phases. The results showed that: Machinery tillage had positive and negative influence on soil structure, soil in top cultivated layer can be loosened and ameliorated however the subsoil accumulation of compaction was resulted. For heavy and medium machinery, subsoil compaction formed in the soil depth of 41~60cm and 31~40cm, respectively; however during the soil depth of 17.5~30cm under medium machinery operation there was a new plow pan produced because of the depth difference between harvesting and subsoiling. Antecedent water content had a significant effect on soil structure under machinery operations. Higher water antecedent resulted in deeper subsoil compaction at 40cm,which was deeper by 10cm than lower water content and soil compaction accumulation occurred at the first pass under higher water content condition. Besides water content and bulk density, soil organic matter is another key factor for affecting compressive-resilient performance of tillage soil. Secondly, based on the soils sampled from fields of the black soil region, the effects of freeze-thaw cycles on soil structure at different soil depths (0 -- 40 cm, 40 -- 80 cm, 120 -- 160 cm) and size scales (field core sampling

  3. Growth and Physiology of Several Urban Tree Species in Soils Disturbed by Construction Fill or Compaction

    OpenAIRE

    Day, Susan Downing

    1999-01-01

    Experiments were conducted to determine the effects of applying fill soil around existing trees and mechanisms for species tolerance to soil compaction, both common site disturbances in urban forestry. Groups of 22-year-old white oak (Quercus alba) and 13-year-old sweetgum (Liquidambar styraciflua) were subjected to one of three treatments: a control, fill (20 cm of subsoil spread over the root zones), and compacted fill (same as fill soil, but compacted). Additionally, individual trees had t...

  4. Effects of soil moisture content and tractor wheeling intensity on traffic-induced soil compaction

    Directory of Open Access Journals (Sweden)

    Iman AHMADI

    2015-12-01

    Full Text Available Soil compaction causes deleterious effects on physical and mechanical proprieties of agricultural soils. In order to investigate the effect of soil moisture content and tractor wheeling intensity on traffic-induced soil compaction, this study was carried out on a field with clay loam soil. Soil dry bulk density and hydraulic conductivity as well as emergence percentage of corn seedlings and dry mass of the sampled mature plants were considered the dependent variables of the experiment. Independent variables consisted of soil moisture content with five levels (12, 15, 17, 19, and 21%, traffic intensity with three levels (four, two, and zero passes of tractor wheel (tractor model: John Deere 3350 from the entire area of the plot, and soil sampling depth with three levels (0-10, 10-20, and 20-30 cm. According to the results of this study, gradual increase in soil water content generally resulted in an increase in soil bulk density; moreover, increasing the tractor wheeling intensity from 0 to 4 passes increased bulk density by 13%. Furthermore, the driest soil water content had the highest and the wettest soil water content had the lowest emergence percentage of corn seedlings among the treatments; moreover, traffic intensity treatment inversely affected the emergence percentage of corn seedlings and the dry mass of mature plants. To sum up, these results indicate that, for improving water permeability and reducing dry bulk density of the examined clay loam soil, as well as better emergence of corn seedlings and ultimately increasing crop yield, it is recommended to avoid wheeling when soil moisture content is high, reduce the number of machinery wheel passes from the farm as low as possible, and restrict the wheel passes to fixed strips along the field, whenever possible.

  5. Runoff and erosion effects after prescribed fire and wildfire on volcanic ash-cap soils

    Science.gov (United States)

    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 NOTHERN IDAHO AND WESTERN MONTANA. THE MEASURED FIRE EFFECTS WERE DIFFERENTIATED BY BURN SEVERITY ...

  6. Subsoil compaction caused by heavy sugarbeet harvesters in southern Sweden; II. soil displacement during wheeling and model computations of compaction

    NARCIS (Netherlands)

    Arvidsson, J.; Trautner, A.; Akker, van den J.J.H.; Schjonning, P.

    2001-01-01

    Traffic with high wheel loads in combination with high inflation pressure implies a risk for subsoil compaction, but effects will depend on the soil strength. Soil displacement during traffic with a heavy sugarbeet harvester (total load approximately 35 Mg on two axles) was determined at 0.3, 0.5 an

  7. 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...... saturated conditions. Data showed that particle size markedly affects the effective diameter of the drained pores active in leading gas through the sample at –100 cm H2O of soil water matric potential (calculated from Dp and ka) as well as the average pore diameter at half saturation (calculated from...... the water retention curve), both exhibiting similar and exponential relationships with D50. Under variably saturated conditions, higher Dp and ka in coarser sand (larger D50) were observed due to rapid gas diffusion and advection through the less tortuous large-pore networks. In addition, soil compaction...

  8. 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.

  9. 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.

  10. 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

    functioning are scarce. This study evaluated and quantified persistent effects of subsoil compaction on soil pore structure and gas transport processes using intact cores taken at 0.3, 0.5, 0.7 and 0.9 m depth from a loamy soil in a compaction experiment in southern Sweden (Brahmehem Farm). The treatments...... 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......The ever-increasing weight of agricultural machines exacerbates the risk of subsoil compaction, a condition believed to be persistent and difficult to alleviate by soil tillage and natural loosening processes. However, experimental data on the persistency of subsoil compaction effects on soil pore...

  11. Soil Compaction and Recovery after Mechanized Final Felling of Italian Coastal Pine Plantations

    OpenAIRE

    Kleibl, Miroslav; Klvač, Radomir; Lombardini, Carolina; Porhaly, Josef; Spinelli, Raffaele

    2014-01-01

    This study gauged the severity and permanence of soil compaction associated with mechanized clear felling of umbrella pine plantations. We tested three treatments: not harvested, harvested one year earlier and harvested six years earlier. Each treatment was replicated eight times in randomly distributed 0.5 ha plots, on the same soil type. Soil compaction was assessed by gauging soil bulk density, penetration resistance, deflection under impact and CO2 concentration. These parameters were mea...

  12. Shrinkage/swelling of compacted clayey loose and dense soils

    Science.gov (United States)

    Nowamooz, Hossein; Masrouri, Farimah

    2009-11-01

    This Note presents an experimental study performed on expansive compacted loose and dense samples using osmotic oedometers. Several successive wetting and drying cycles were applied in a suction range between 0 and 8 MPa under different values of constant net vertical stress (15, 30, and 60 kPa). During the suction cycles, the dense samples showed cumulative swelling strains, while the loose samples showed volumetric shrinkage accumulation. At the end of the suction cycles, the volumetric strains converged to an equilibrium stage that indicated elastic behavior of the swelling soil for any further hydraulic variations. At this stage, the compression curves for the studied soil at the different imposed suctions (0, 2, and 8 MPa) converged towards the saturated state curve for the high applied vertical stresses. We defined this pressure as the saturation stress(P). The compression curves provided sufficient data to examine the soil mechanical behavior at the equilibrium stage. To cite this article: H. Nowamooz, F. Masrouri, C. R. Mecanique 337 (2009).

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

    OpenAIRE

    Ter-Martirosyan Zaven Grigor’evich; Ter-Martirosyan Armen Zavenovich; Trinh Tuan Viet

    2015-01-01

    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 o...

  14. THE EFFECT OF MIXING WITH ORGANIC SOIL ON CHANGES IN SOME PHYSICAL PROPERTIES OF A COMPACTED CLAY LOAM SOIL

    Directory of Open Access Journals (Sweden)

    Abdullah BARAN

    1996-01-01

    Full Text Available In this research, the effect of organic soil on changes in total pore space, aeration porosity, available water content and hydraulic conductivity of a compacted clay loam were investigated. By adding organic soil at rates of 0 %, 1 %, 2 % and 4 % to soil, mixtures were compacted at compaction levels of 0 kg/cm2, 0.21 kg/cm2, 1.98 kg/cm2 and 3.95 kg/cm2 Some physical properties of compacted soil were determined. Compaction decreased total pore space, areation porosity, available water content and hydraulic conductivity, but in samples with the mixing rate of 4 %, all properties inspected were affected positively in all compaction levels, except available water content

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

    OpenAIRE

    Weizheng Liu; Shuai Qu; Zhihong Nie; Junhui Zhang

    2016-01-01

    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...

  16. A long-term soil structure observatory for post-compaction soil structure evolution: design and initial soil structure recovery observations

    Science.gov (United States)

    Keller, Thomas; Colombi, Tino; Ruiz, Siul; Grahm, Lina; Reiser, René; Rek, Jan; Oberholzer, Hans-Rudolf; Schymanski, Stanislaus; Walter, Achim; Or, Dani

    2016-04-01

    Soil compaction due to agricultural vehicular traffic alters the geometrical arrangement of soil constituents, thereby modifying mechanical properties and pore spaces that affect a range of soil hydro-ecological functions. The ecological and economic costs of soil compaction are dependent on the immediate impact on soil functions during the compaction event, and a function of the recovery time. In contrast to a wealth of soil compaction information, mechanisms and rates of soil structure recovery remain largely unknown. A long-term (>10-yr) soil structure observatory (SSO) was established in 2014 on a loamy soil in Zurich, Switzerland, to quantify rates and mechanisms of structure recovery of compacted arable soil under different post-compaction management treatments. We implemented three initial compaction treatments (using a two-axle agricultural vehicle with 8 Mg wheel load): compaction of the entire plot area (i.e. track-by-track), compaction in wheel tracks, and no compaction. After compaction, we implemented four post-compaction soil management systems: bare soil (BS), permanent grass (PG), crop rotation without mechanical loosening (NT), and crop rotation under conventional tillage (CT). BS and PG provide insights into uninterrupted natural processes of soil structure regeneration under reduced (BS) and normal biological activity (PG). The two cropping systems (NT and CT) enable insights into soil structure recovery under common agricultural practices with minimal (NT) and conventional mechanical soil disturbance (CT). Observations include periodic sampling and measurements of soil physical properties, earthworm abundance, crop measures, electrical resistivity and ground penetrating radar imaging, and continuous monitoring of state variables - soil moisture, temperature, CO2 and O2 concentrations, redox potential and oxygen diffusion rates - for which a network of sensors was installed at various depths (0-1 m). Initial compaction increased soil bulk density

  17. Soil compaction and vegetation cover in a Scots pine stand at the Mediterranean rangelands

    OpenAIRE

    Aroca Fernández, Mª José; Bravo Fernandez, Jose Alfredo; Gastón González, Aitor; Serrada Hierro, Rafael

    2011-01-01

    Right development of ROOT SYSTEMS is essential to ensure seedling survival in the initial stages of natural regeneration processes. Soil compaction determines this development both because of its influence on soil Tª & moisture dynamics and for its direct effect on soil mechanical impedance to root growth. All this effects can be assessed as a whole through soil penetration resistance (Soil Strength) measurements. SOIL STRENGTH has been usually evaluated in forest research in connection with ...

  18. Portable penetrometer for agricultural soil: sensitivity test to identify critical compaction depth

    Directory of Open Access Journals (Sweden)

    João Carlos Medeiros

    2010-12-01

    Full Text Available To express the negative effects of soil compaction, some researchers use critical values for soil mechanical strength that severely impair plant growth. The aim of this study was to identify this critical compaction depth, to test the functionality of a new, portable penetrometer developed from a spring dynamometer, and compare it to an electronic penetrometer traditionally used in compaction studies of agricultural soils. Three soils with distinct texture were conventionally tilled using a disk plow, and cultivated with different plant species. The critical soil resistance defined to establish critical compaction depth was equal to 1.5 MPa. The results of the new equipment were similar to the electronic penetrometer, indicating its viability as a tool for assessing the soil physical conditions for plant growth.

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

    OpenAIRE

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

  20. Functional attributes: Compacting vs decompacting earthworms and influence on soil structure

    Directory of Open Access Journals (Sweden)

    Arnauth Martinez GUÉI, Yannick BAIDAI, Jérôme Ebagnerin TONDOH,Jeroen HUISING

    2012-08-01

    Full Text Available A short term field mesocosm experiment was performed in semi-deciduous forest areas of Ivory Coast to assess the impact of a decompacting (Hyperiodrilus africanus, Eudrilidae and two compacting (Millsonia omodeoi and Dichogaster terraenigrae, Acanthodrilidae earthworm species on soil properties. These species have been selected for their predominance in the region and their contrasting impact on soil structure. The experimental design consisted of a treatment without worms (control, and treatments with one, two or three species of earthworms. Both compacting and decompacting earthworms increased water infiltration rate in all treatments, with marked impact in H. africanus and M. omodeoi+D. terraenigrae treatments. Interactions between compacting and decompacting species resulted in more large aggregates in comparison to when the compacting species D. terraenigrae was alone. This may be accounted for by their compacting attribute as compacting earthworms are responsible for producing the highest number of large aggregates. The low values of mean weight diameter in treatments combining decompacting and compacting earthworms compared with compacting "M. omodeoi" one also confirmed the trend of decline in soil compaction in the presence of the decompacting species. These results showed positive impact of species richness on soil structure regulation, which is crucial in ecosystem productivity and support consequently the insurance hypothesis. In fact, this study showed that the preservation of earthworm species belonging to these two contrasting functional groups is essential for the maintenance of stable soil structure regulation in agro-tropical ecosystems [Current Zoology 58 (4: 556–565, 2012].

  1. 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

  2. Influence of vertical loads on lateral pile group response considering soil-pile-cap interactions

    Science.gov (United States)

    Hussien, Mahmoud N.; Tobita, Tetsuo; Iai, Susumu

    This paper presents the results of a numerical investigation conducted to study the effect of vertical loads on lateral response of a free head and a capped pile group in sand. A coupled soil-pile system is idealized through 2D finite elements with soil models idealized by a hyperbolic type multiple shear mechanism. The analysis focuses on the five piles in the middle row of a 3x5 pile group spaced at 3.92-pile diameters. The interaction between a pile and the surrounding soil in the 3D type is idealized in the 2D analysis using soil-pile interaction springs with a hysteretic non-linear load displacement relationship. The presence of vertical loads on free head piles increases the confining pressures in the sand deposit confined by the piles but the rate of increase in those outside the group is relatively small, resulting in the difference in a balance of lateral soil pressures acting at the back of and in front of individual piles. A vertical load applied to a group pile with a uniform vertical displacement of 0.1 pile diameter decreases the lateral resistance of the leading pile (pile 1) by 10 % and increases the lateral resistance of piles 3 and 5 by 14 and 35 %, respectively. The same trend with higher percentages of increase or decrease is observed in the capped pile group case.

  3. Gamma-ray-computed tomography to investigate compaction on sewage-sludge-treated soil

    Energy Technology Data Exchange (ETDEWEB)

    Pires, L.F. E-mail: lfpires@cena.usp.br; Macedo, J.R. de; Souza, M.D. de; Bacchi, O.O.S.; Reichardt, Klaus

    2003-07-01

    Soil compaction is one of the fundamental parameters to evaluate the environmental impact of agricultural machinery traffic on soils. Compaction causes modifications on soil physical properties such as changes in porosity and structure that are related to soil water movement and gas exchange The objective of this work was to evaluate soil surface sealing after sewage-sludge application, and the influence of agricultural machinery traffic, through computed tomography. A first generation tomograph was used having a {sup 137}Cs source and a 3 inx3 in NaI(Tl) scintillation crystal detector coupled to a photomultiplier tube. Image analysis and tomographic unit profiles could successfully be used for the detection of soil surface sealing and soil compaction due to machinery traffic associated to sewage-sludge application.

  4. Effect of Bogie Track and Slash Reinforcement on Sinkage and Soil Compaction in Soft Terrains

    OpenAIRE

    Gerasimov, Yuri; Katarov, Vasily

    2010-01-01

    A study of the effect of bogie wheel track and slash reinforcement on the sinkage (as rut depth) and soil compaction (as bulk density) of silt loam soil was carried out in spring and autumn at two harvesting sites in Russia. A Ponsse ELK forwarder loaded with 16 m3 of timber, fitted and unfitted with bogie tracks, was repeatedly driven on forest soil for 1–10 passes. The degree of sinkage and soil compaction was measured at two soil moisture contents: moist (W = 80%) and wet (W = 93%) after e...

  5. THE EFFECT OF DIFFERENT COMPACTION DURATIONS ON CHANGES IN SOME PHYSICAL PROPERTIES OF A CLAY LOAM SOIL

    Directory of Open Access Journals (Sweden)

    Damla BENDER

    1997-02-01

    Full Text Available In this research, the effect of different compaction durations on changes of total pore spaces, available water content, aeration porosity and hydraulic conductivity of a compacted clay loam soil were investigated. Soil samples were compacted at compaction levels of 0 kg/cm2 , 1.98 kg/cm2 and 3.00 kg/cm2 for 1, 2 and 4 minutes, then, above mentioned physical properties of soil samples were determined. Total pore spaces, available water content, aeration porosity and hydraulic conductivity of soil samples were not significantly affected from the compaction durations, but significantly decreased with increasing compaction levels.

  6. Aggregate water stability of sandy and clayey loam soils differently compacted with and without wheat plants

    OpenAIRE

    Bazzoffi P.; Balashov E.

    2003-01-01

    The objectives of our studies were to: 1) estimate the effects of compaction of sandy loam and clayey loam soils on growth parameters of winter wheat plants, 2) evaluate the resilien- ce capacity of the root system for the water-stable aggregation of compacted soils. Soil samples at field capacity were placed into pots with an initial bulk density of 1.2 Mg m-3 and compacted with ground contact pressures of 51, 103 and 154 kPa using a hydraulic compressor. Five plants in each pot were allowed...

  7. Dynamic compaction treatment technology research of red clay soil embankment in southern mountains

    Institute of Scientific and Technical Information of China (English)

    刘建华; 袁剑波; 熊虎; 陈伟

    2008-01-01

    High liquid limit soil generally adopted in expressway embankment construction of southern mountains, which often expresses some characteristics including high moisture content, high porosity ratio, low permeability, high compressibility, certain disintegration, and so on. Spring soil phenomenon and inhomogeneous compaction have effects on the quality of embankment construction, just because the water in soil is difficult to evaporate. Based on the study of reinforcement mechanism for high liquid limit soil, in situ tests for dynamic compaction treatment in Yizhang-Fengtouling expressway embankment were developed. The reliable and economical dynamic compaction treatment methods and the construction technology for large range high liquid limit soil embankment in southern mountains expressway were discussed. In the process, convenient measurement methods were adopted to evaluate the treatment effects. The test results show that the dynamic compaction method has good treatment effects on the local red clay embankment. The embankment compaction degree is improved with compactness coming to 90% around tamping pits and compactness over 95% in tamping pits interior after tamping. The bearing capacity, the physical mechanic-property and the shear strength for soil are obviously improved, which are enhanced with cohesive strength increasing over 10 kPa and compression modulus increasing over 3 MPa.

  8. 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...... viability. This entails a steady increase in the size and weight of the agricultural machinery (DPSIR-P) exerting the specific pressures on the soil system. Simulations using historical data for agricultural machinery show significant increases in the mechanical stresses exerted on the soil profile during......, dimensions, and interconnections of soil pores. Subsequent impacts on ecosystem services (subtle DPSIR-I aspects) include a decrease in crop production, an impaired soil filtering of pollutants, and the risk of higher greenhouse gas emissions. The natural ability of compacted subsoil to recover is poor. We...

  9. The sensitivity of barley, field beans and sugar beet to soil compaction

    OpenAIRE

    Brereton, Jeremy Charles

    1986-01-01

    The sensitivity of spring barley (Hordeum vulgare, cv. Carnival), field beans (Vicia faba, ev. Maris Bead) and sugar beet (Beta vulgaris,cv. Monoire) to topsoil compaction induced by tractor wheelings, post sowing, on a coarse gravelly loam of the Arrow series was investigated in 1983 and 1984. The study revealed that in both years topsoil compaction increased the dry bulk density, vane shear strength and cone resistance of the soil. Although compaction reduced only the plant population o...

  10. Survey of soil compaction on oil and gas leases in east-central Alberta

    International Nuclear Information System (INIS)

    A study was conducted to examine reasons for topsoil compaction at oil and gas well-sites. A survey of 20 well-sites in east-central Alberta was was made, comparing the six methods which are commonly used to evaluate soil compaction. The methods described were: bulk density, bulk density corrected for organic matter content, total porosity, estimated hydraulic conductivity, mechanical impedance, and macro-pore volume. The survey was also used to evaluate the extent of soil compaction on well-sites with different soil types and different reclamation conditions. It was shown that about one third of the well-sites had higher mechanical impedance than the adjacent farmland soils. The probable causes for topsoils being more frequently compacted than subsoils were also described. 33 refs., 10 tabs., 4 figs

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

    International Nuclear Information System (INIS)

    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 CO2 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 (60Co) 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 CO2 evolution from soil, reflecting variations in dynamics of the heterotrophic soil microbiota. CO2 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 of

  12. Using Tension Infiltrometry to Assess the Effect of Subsoil Compaction on Soil Hydraulic Properties

    Science.gov (United States)

    Schwen, Andreas; Carrick, Sam; Buchan, Graeme

    2010-05-01

    Soil compaction is a major cause of soil degradation all over the world. The related changes in soil physical parameters are of growing importance in agricultural production. To understand fully the effects of different degrees of subsoil compaction on the growth and yield of arable plants requires knowledge of changes in both the soil hydraulic conductivity function, and in the soil water retention curve. In the present study measurements of the hydraulic properties were obtained on an arable field in the Canterbury Plains, South Island, New Zealand. The soil is classified as Templeton silt loam. The uppermost 15 cm of the soil were removed and replaced following five contrasting subsoil treatments. The subsoil was either cultivated (loosened), untreated, or compacted using a heavy roller with three different steps of compaction. Five randomised replications of each subsoil treatment were established. At each of the 25 plots, infiltration measurements were obtained at two depths: on the soil surface and within the compacted soil layer at 18 cm depth. Tension infiltrometry was used, as this method allows the precise and in situ determination of the hydraulic properties at near-saturated conditions. These conditions coincide with flow activation in the macro porosity of the soil. Thus, this method is also suitable to determine the amount and distribution of macro pores, as well as preferential flow paths in soils. Only a few studies have measured the near-saturated parts of the retention and conductivity curves of Templeton soils. The supply tensions were -15 cm, -10 cm, -4 cm, -1 cm, and 0 cm. Undisturbed soil samples were taken with steel cores before each measurement in the vicinity of each measurement site, enabling measurement of the initial and saturated water contents in the laboratory. Post-measurement samples were also taken directly below the infiltration disc to measure the final water content. The cumulative infiltration together with the initial and

  13. 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.

  14. Persistent subsoil compaction and its effects on preferential flow patterns in a loamy till soil

    DEFF Research Database (Denmark)

    Etana, A; Larsbo, M; Keller, T;

    2013-01-01

    sugar beet harvester with a wheel load of c. 10.4 Mg. Investigations included penetration resistance, bulk density, water retention, saturated hydraulic conductivity, in situ near-saturated hydraulic conductivity, and dye tracing experiments. The measurements of penetration resistance and bulk density...... clearly showed the persistence of subsoil compaction. In addition, both macroporosity and saturated and near-saturated hydraulic conductivity were smaller in the compacted plots, although these differences were not statistically significant. Dye tracing allowed us to visualize flow patterns in the soil...... and to quantitatively distinguish compacted and non-compacted subsoil profiles. Despite significant soil textural heterogeneity across the experimental field, the dye tracing data showed that persistent compaction may enhance preferential flow....

  15. Terranimo® – a web-based tool for evaluating soil compaction

    Directory of Open Access Journals (Sweden)

    Matthias Stettler

    2014-06-01

    Full Text Available Based on experimental data from wheeling experiments, a web-based model for the simulation of stress and the evaluation of the soil compaction risk under agricultural machinery named Terranimo® has been developed. Terranimo® incorporates a model for prediction of contact area, shape and stress distribution in the tyre–soil interface from wheel load and readily-available tyre parameters and the topsoil strength. In Terranimo® pedotransfer functions are used to estimate soil strength from clay content and matric potential. Principally, by limiting the imposed stress to below soil strength, the risk of soil compaction and undesirable changes of soil structure – and hence soil functions – can be minimized.

  16. Functional attributes: Compacting vs decompacting earthworms and influence on soil structure

    Institute of Scientific and Technical Information of China (English)

    Arnauth Martinez GU(E)I; Yannick BAIDAI; Jér(o)me Ebagnerin TONDOH; Jeroen HUISING

    2012-01-01

    A short term field mesocosm experiment was performed in semi-deciduous forest areas of Ivory Coast to assess the impact of a decompacting (Hyperiodrilus africanus,Eudrilidae) and two compacting (Millsonia omodeoi and Dichogaster terraenigrae,Acanthodfilidae) earthworm species on soil properties.These species have been selected for their predominance in the region and their contrasting impact on soil structure.The experimental design consisted of a treatment without worms (control),and treatments with one,two or three species of earthworms.Both compacting and decompacting earthworms increased water infiltration rate in all treatments,with marked impact in H.africanus and M.omodeoi+D.terraenigrae treatments.Interactions between compacting and decompacting species resulted in more large aggregates in comparison to when the compacting species D.terraenigrae was alone.This may be accounted for by their compacting attribute as compacting earthworms are responsible for producing the highest number of large aggregates.The low values of mean weight diameter in treatments combining decompacting and compacting earthworms compared with compacting “M.omodeoi” one also confirmed the trend of decline in soil compaction in the presence of the decompacting species.These results showed positive impact of species richness on soil structure regulation,which is crucial in ecosystem productivity and support consequently the insurance hypothesis.In fact,this study showed that the preservation of earthworm species belonging to these two contrasting functional groups is essential for the maintenance of stable soil structure regulation in agro-tropical ecosystems.

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

    International Nuclear Information System (INIS)

    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

  18. Characterization of field compaction using shrinkage analysis and visual soil examination

    Science.gov (United States)

    Johannes, Alice; Keller, Thomas; Weisskopf, Peter; Schulin, Rainer; Boivin, Pascal

    2016-04-01

    Visual field examination of soil structure can be very useful in extension work, because it is easy to perform, does not require equipment or lab analyses and the result is immediately available. The main limitations of visual methods are subjectivity and variation with field conditions. To provide reliable reference information, methods for objective and quantitative assessment of soil structure quality are still necessary. Soil shrinkage analysis (ShA) (Braudeau et al., 2004) provides relevant parameters for soil functions that allow precise and accurate assessment of soil compaction. To test it, we applied ShA to samples taken from a soil structure observatory (SSO) set up in 2014 on a loamy soil in Zurich, Switzerland to quantify the structural recovery of compacted agricultural soil. The objective in this presentation is to compare the ability of a visual examination method and ShA to assess soil compaction and structural recovery on the SSO field plots. Eighteen undisturbed soil samples were taken in the topsoil (5-10 cm) and 9 samples in the subsoil (30-35 cm) of compacted plots and control. Each sample went through ShA, followed by a visual examination of the sample and analysis of soil organic carbon and texture. ShA combines simultaneous shrinkage with water retention measurements and, in addition to soil properties such as bulk density, coarse and fine porosity, also provides information on hydrostructural stability and plasma and structural porosity. For visual examination the VESS method of Ball et al. (2007) was adapted to core samples previously equilibrated at -100 hPa matric potential. The samples were randomly and anonymously scored to avoid subjectivity and were equilibrated to insure comparable conditions. Compaction decreased the total specific volume, as well as air and water content at all matric potentials. Structural porosity was reduced, while plasma porosity remained unchanged. Compaction also changed the shape of the shrinkage curve: (i

  19. 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......The high input of mechanical energy in common agricultural practice can negatively affect soil structure. The impact of compaction (P) and rotovation (R) on soil pore characteristics was compared with those in soil from untreated reference (U) plots of a loamy sand soil receiving for 14 yr, either......). Water retention, air permeability and gas diffusivity were determined at )100 hPa in both years and for a range of water potentials in one of the years. The continued addition of animal manure had increased OC, BC, and Chot compared with the soil receiving only mineral fertilizer. Soil under treatment...

  20. 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.

  1. Terranimo® – a web-based tool for evaluating soil compaction

    OpenAIRE

    Matthias Stettler; Thomas Keller; Peter Weisskopf; Mathieu Lamandé; Poul Lassen; Per Schjønning

    2014-01-01

    Based on experimental data from wheeling experiments, a web-based model for the simulation of stress and the evaluation of the soil compaction risk under agricultural machinery named Terranimo® has been developed. Terranimo® incorporates a model for prediction of contact area, shape and stress distribution in the tyre–soil interface from wheel load and readily-available tyre parameters and the topsoil strength. In Terranimo® pedotransfer functions are used to estimate soil strength from clay ...

  2. Tensile behaviour of unsaturated compacted clay soils — A direct assessment method.

    OpenAIRE

    Stirling, R.A.; Hughes, P N; Davie, C. T.; Glendinning, S.

    2015-01-01

    This paper presents a new method for testing the behaviour of soils placed under tensile load and demonstrates its suitability for testing a number of soil types under various conditions including saturation, compaction and stabilisation. Validation of the results obtained for the soils at relatively low saturation has been conducted using the established Brazilian (indirect) test for measuring the tensile strength of brittle materials. A fair comparison has been found and the results highlig...

  3. The effect of clod size and degree of saturation on a compacted artificial soil

    OpenAIRE

    Argany Moure, Ester

    2011-01-01

    Anglès: The extremely complex nature ofthe physical properties ofunsaturated soils with three phase material such as a compacted clay containing both air and water as pare fluids, delayed considerably the development of an understanding of the behaviour of partially saturated soils. This issue plus the fact tbat soil mecbanics was first developed in northern Europe and north-east USA where the climate is cool and wet so that the unsaturated zone is nonnally where the constructions are impleme...

  4. Effect of rock fragment addition on hydro-dispersive properties of compacted soils

    Science.gov (United States)

    Gargiulo, Laura; Mele, Giacomo; Coppola, Antonio; De Mascellis, Roberto; Di Matteo, Bruno; Terribile, Fabio; Basile, Angelo

    2014-05-01

    Compaction of agricultural soils is an increasingly challenging problem for crop production and environment. Mechanization of agricultural practices is one of the main factors inducing degradation of soil structure, especially in fragile soils with little organic matter and low shrinking-swelling capacity. Moreover, rock picking from stony soils is a routine practice to avoid tillage problems in some agricultural productions, but stone removal can significantly increase soil compaction, which lowers water infiltration rates and increases surface runoff and soil erosion. The practice of crushing and returning smaller rock fragments to the field could reduce the above problems. The aim of this work was to test the addition of rock fragments as practice to restore soil physical quality of not-stony soils susceptible to compaction. We carried out a lab experiment mixing five different volume concentrations (5%, 10%, 15%, 25% and 35%) of 4-8mm rock fragments with an Alfisol and an Entisol, showing compact structure and water stagnation problems in field. The repacked samples have undergone nine wet/dry cycles in order to induce soil structure formation and its stabilization. Bulk density, porosity and soil hydraulic properties and hydro-dispersive characteristics were measured. Soil hydraulic properties, namely water retention and hydraulic conductivity, were inferred from an infiltration experiment performed by a tension infiltrometer disc coupled with an inverse parameter estimation method; hydro-dispersive characteristics were performed from a tracer inflow-outflow experiment conducted in unsaturated condition, followed by the analysis of the breakthrough curve. Soil image analysis was used to enhance parameterization of the hydrological models near saturation. Preliminary results showed that bulk density significantly changed only after addition of 35% of rock fragments and a good physical restoration was reached at 15% volume concentration in Entisol and at 25% in

  5. Effects of soil compaction on seedling morphology, growth, and architecture of chestnut-leaved oak (Quercus castaneifolia)

    OpenAIRE

    Jourgholami M; Khoramizadeh A; Zenner EK

    2016-01-01

    Soil compaction following traffic by heavy-timber harvesting machinery usually causes an increase in soil strength, that is a stress factor negatively affecting the growth of newly germinated seedlings. This study used a soil strength experiment carried out in a greenhouse to test the hypotheses that increasing soil strength would adversely affect seedling morphology and alter seedling architecture by changing biomass allocation patterns. We explored the effects of soil compaction in a loam t...

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

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Luiz F.; Arthur, Robson C.J.; Correchel, Vladia; Bacchi, Osny O.S.; Reichardt, Klaus [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil); Brasil, Rene P. Camponez do [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz. Dept. de Engenharia Rural

    2004-09-15

    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 {sup 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)

  7. 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

  8. Study on the Natural Soil Properties Endau Rompin National Park (PETA as Compacted Soil Liner for Sanitary Landfill

    Directory of Open Access Journals (Sweden)

    Zulkifli Ahmad

    2013-11-01

    Full Text Available Abstract: This paper reviews and extends an understanding of a study on potential suitability of the natural soil in Endau Rompin National Park (PETA as a compacted soil liner for sanitary landfill. Since the demand for landfill system becomes obvious so that concerning construction and operation of landfills are increasing. A number of studies have been conducted for the liner system of landfill. Hence, study is required to choose the suitable type of material as liner barrier for the landfill system in term to achieve optimum long term performance. The sanitary landfill plays an important role in the framework of solid waste disposal. The compacted soil liner is a part of a liner structure for landfill to restrict leachate migration from facility into the environment. So that, if the landfill system is not well manage it will contaminate the soil and ground water, thus presenting a risk to human and environmental health. This study, natural soil will be taken from Endau Rompin National Park (PETA, Johor as soil sample for testing. Natural soil is an economy material as a liner system, and it does not decay easily from time to time. So it is an ideal material as a sanitary landfill liner system. In short, the purpose of this study is to compile and organize available information on the use of laboratory testing, as well as providing some guidance on the use of natural soil as barrier layer of landfill and also it suitability of physical and chemical properties natural soil as barrier layer of landfill. Based on the laboratory testing were conducted, found that soil sample taken form Endau Rompin National Park (PETA is suitable as compacted soil liner for sanitary landfill.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hamdi, Noureddine, E-mail: nouryhamdi@gmail.com [Centre National des Recherches en Science des Materiaux, Borj Cedria Techno-Park, B.P. 95-2050, Hammam Lif, Tunis (Tunisia); Srasra, Ezzeddine [Centre National des Recherches en Science des Materiaux, Borj Cedria Techno-Park, B.P. 95-2050, Hammam Lif, Tunis (Tunisia)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Examined the hydraulic conductivity evolution as function of dry density of Tunisian clay soil. Black-Right-Pointing-Pointer Follow the hydraulic conductivity evolution at long-term of three clay materials using the waste solution (pH=2.7). Black-Right-Pointing-Pointer Determined how compaction affects the hydraulic conductivity of clay soils. Black-Right-Pointing-Pointer 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 Multiplication-Sign 10{sup -10}, 2.08 Multiplication-Sign 10{sup -9} and 6.8 Multiplication-Sign 10{sup -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{sup 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{sup 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.

  10. Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity. Forest Service research paper

    Energy Technology Data Exchange (ETDEWEB)

    Amaranthus, M.P.; Page-Dumroese, D.; Harvey, A.; Cazares, E.; Bednar, L.F.

    1996-05-01

    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 pine (Pinus monticola Dougl. ex D. Don) seedlings following outplanting. Moderate and severe soil compaction significantly reduced nonmycorrhizal root tip abundance on both Douglas-fir and western white pine seedlings (p less than or equal to 0.05). Ectomycorrhizal root tip abundance was significantly reduced on Douglas-fir seedlings in severely compacted areas with bole and crowns and bole, crowns, and forest floor removed. Ectomycorrhizal diversity also was significantly reduced on Douglas-fir seedlings in all severely compacted areas.

  11. Liquefaction mitigation in silty soils using composite stone columns and dynamic compaction

    Institute of Scientific and Technical Information of China (English)

    T.Shenthan; R.Nashed; S.Thevanayagam; G. R. Martin

    2004-01-01

    The objective of this study is to develop an analytical methodology to evaluate the effectiveness ofvibro stone column (S.C.) and dynamic compaction (D.C.) techniques supplemented with wick drains to densify and mitigate liquefaction in saturated sands and non-plastic silty soils. It includes the following: (i) develop numerical models to simulate and analyze soil densification during S.C. installation and D.C. process, and (ii) identify parameters controlling post-improvement soil density in both cases, and (iii) develop design guidelines for densification of silty soils using the above techniques. An analytical procedure was developed and used to simulate soil response during S.C. and D.C. installations, and the results were compared with available case history data. Important construction design parameters and soil properties that affect the effectiveness of these techniques, and construction design choices suitable for sands and non-plastic silty soils were identified.The methodology is expected to advance the use of S.C. and D.C. in silty soils reducing the reliance on expensive field trials as a design tool. Thc ultimate outcome of this research will be design charts and design guidelines for using composite stone columns and composite dynamic compaction techniques in liquefaction mitigation of saturated silty soils.

  12. THE EFFECT OF DIFFERENT COMPACTION DURATIONS ON CHANGES IN SOME PHYSICAL PROPERTIES OF A CLAY LOAM SOIL

    OpenAIRE

    BENDER, Damla; Abdullah BARAN; ÖZKAN, İlhami

    1997-01-01

    In this research, the effect of different compaction durations on changes of total pore spaces, available water content, aeration porosity and hydraulic conductivity of a compacted clay loam soil were investigated. Soil samples were compacted at compaction levels of 0 kg/cm2 , 1.98 kg/cm2 and 3.00 kg/cm2 for 1, 2 and 4 minutes, then, above mentioned physical properties of soil samples were determined. Total pore spaces, available water content, aeration porosity and hydraulic conductivity ...

  13. 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.

  14. 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;

  15. SOCOMO: a soil compaction model to calculate soil stresses and the subsoil carrying capacity

    NARCIS (Netherlands)

    Akker, van den J.J.H.

    2004-01-01

    Intensification of crop rotation and increasing use of machinery with high wheel loads are clearly related to compaction of the subsoil. Subsoil compaction is persistent and the effect of natural and artificial loosening has been disappointing. Therefore, prevention of subsoil compaction is the best

  16. Upscaling spatially heterogeneous parameterisations of soil compaction to investigate catchment scale flood risk.

    Science.gov (United States)

    Coates, Victoria; Pattison, Ian

    2016-04-01

    Upscaling land management signals observed at the point scale to the regional scale is challenging for three reasons. Individual catchments are unique and at the point scale land management signals are spatially and temporally variable, depending on topography, soil characteristics and on the individual characteristics of a rainfall event. However at larger scales land management effects diffuse and climatic or human induced signals have a larger impact. This does not mean that there is no influence on river flows, just that the effect is not discernible. Land management practices in different areas of the catchment vary spatially and temporally and their influence on the flood hydrograph will be different at different points within the catchment. Once the water enters the river, the land management effects are disturbed further by hydrodynamic and geomorphological dispersion. Pastoral agriculture is the dominant rural land cover in the UK (40% is classified as improved/ semi-natural grassland - Land Cover Map 2007). The intensification of agriculture has resulted in greater levels of soil compaction associated with higher stocking densities in fields. Natural flood management is the alteration, restoration or use of landscape features to reduce flood risk. Soil compaction has been shown to change the partitioning of rainfall into runoff. However the link between locally observed hydrological changes and catchment scale flood risk has not yet been proven. This paper presents the results of a hydrological modelling study on the impact of soil compaction on downstream flood risk. Field experiments have been conducted in multiple fields in the River Skell catchment, in Yorkshire, UK (area of 120km2) to determine soil characteristics and compaction levels under different types of land-use. We use this data to parameterise and validate the Distributed Physically-based Connectivity of Runoff model. A number of compaction scenarios have been tested that represent

  17. Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

    Science.gov (United States)

    Udawatta, Ranjith P.; Gantzer, Clark J.; Anderson, Stephen H.; Assouline, Shmuel

    2016-05-01

    Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diameter Advanced Photon Source (synchrotron facility) using X-ray CMT. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3-DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN) = 10-CN/Co and P(PL) = 10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (63.7 and 61 µm; p treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

  18. IMPACTS OF FOREST HARVESTING OPERATIONS ON SOIL COMPACTION IN SCOTCH PINE-FIR MIXED STANDS (ÇANKIRI SAMPLE)

    OpenAIRE

    MENEMENCİOĞLU, Kayhan; BUĞDAY, Ender; Ercanli, İlker

    2013-01-01

    This study investigated soil compaction, caused by tree felling and ground based forest harvesting operations, in sandy loamy brown forest soil, located in mixed forest stand harvesting units. In the study area, conventional forest harvesting is still practiced and this resulted in considerable soil compaction. As the forests are on the mountainous landscape, ground skidding is carried out by human, animal or tractor power. The impacts of harvesting operations in felling and skidding areas on...

  19. Reducing the recruitment of sedimented algae and nutrient release into the overlying water using modified soil/sand flocculation-capping in eutrophic lakes

    NARCIS (Netherlands)

    Pan, G.; Dai, L.; Li, L.; He, L.; Li, H.; Bi, L.; Gulati, R.D.

    2012-01-01

    The effect of simultaneously removing algal blooms from water and reducing the resuspension and nutrient release from the sediment was studied using modified local soil/sand flocculation-capping (MLS-capping) in simulated water-sediment systems. Twenty one sediment cores in situ with overlying water

  20. ASSESSMENT OF SOIL COMPACTION UNDER CENTER PIVOT IRRIGATION SYSTEMS AND ITS EFFECT ON CROP PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Khalid Ali Al-Gaadi

    2013-01-01

    Full Text Available A field study on two 12.5 ha plots cultivated with wheat and alfalfa was conducted to determine Soil Compaction (SC, its spatial variability and its effect on crop performance under center pivot irrigation systems. Considering compaction at two tested soil depths, results revealed that the soil of the alfalfa plot exhibited significantly (p<0.01 and p<0.05 for 0 to 10 cm and 0 to 30 cm soil depth, respectively higher compaction values (an average of 1730.328 and 2329.604 kPa, respectively compared to those exhibited by the soil of the wheat plot (averaging at 1339.685 and 2088.903 kPa, respectively. Significant spatial variation of SC was observed within each of the tested plots. SC around pivot wheel tracks was also investigated at a soil depth of 0 to 30 cm for 5.5 m wide strips on both sides of the tracks. Results revealed that the Coefficient of Variation (CV of the SC around the tracks was 9.33 and 16.53% for alfalfa and wheat plots, respectively, suggesting that the SC was not laterally influenced by the wheel tracks. The effect of SC on crop performance, expressed as the Normalized Difference Vegetation Index (NDVI, was investigated on the two plots. Results showed that the NDVI was, in general, inversely proportional to the SC. For both crops, the NDVI was more affected by SC at the top soil layer (0-10 cm depth. Moreover, the alfalfa crop was shown to be significantly influenced by the SC (an average R2 value of 0.3165 and P value of 0.0287, unlike the wheat crop (an average R2 value of 0.0725 and P value of 0.4646.

  1. Swelling/shrinkage of compacted and natural clayey soils; Retrait/gonflement des sols argileux compacts et naturels

    Energy Technology Data Exchange (ETDEWEB)

    Nowamooz, H

    2007-12-15

    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)

  2. Soil compaction limits root development, radiation-use efficiency and yield of three winter wheat (Triticum aestivum L.) cultivars

    DEFF Research Database (Denmark)

    Andersen, Mathias Neumann; Munkholm, Lars Juhl; Nielsen, Anne Lisbeth

    2013-01-01

    Soil compaction has increased during recent years due to the traffic with increasingly heavier machinery. We evaluated the effect of soil compaction on soil penetration resistance, rooting depth, light interception, radiation-use efficiency (RUE) and yield of three different cultivars of winter...... precipitation, the impairment of root penetration resulted in a minor yield decrease of ca. 9% of grain yield in PAC-2 and ca. 8% of total dry matter (DM) in both compaction treatments. The latter was attributed to decreases in interception of light and to efficiency of light energy conversion into biomass...

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

    International Nuclear Information System (INIS)

    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

  4. Effect of soil compaction and organic matter on the early growth of maize (Zea mays) in a vertisol

    OpenAIRE

    T. Crowther; J.O. Ohu; E. Mamman

    2007-01-01

    A laboratory experiment was conducted to determine the emergence and early growth of maize (Zea mays) seeds in a dark clay soil known as vertisol (Typic Pellustert). Three quantities of groundnut haulms were incorporated into the vertisol as organic matter and then compacted at three moisture content levels using four different compactive efforts. The three organic matter and moisture content levels were 2, 4 and 6% (db), and 20, 35 and 50% (w/w), respectively. The four compactive efforts wer...

  5. 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

  6. Soil Compaction Due to Sugarcane (Saccharum officinarum) Mechanical Harvesting and the Effects of Subsoiling on the Improvement of Soil Physical Properties

    Science.gov (United States)

    Naseri, A. A.; Jafari, S.; Alimohammadi, M.

    The main purpose of this study was to shed light on the soil behaviour from compaction point of view before and after harvesting traffic and on the reaction to the subsoiling operation. In this regard two different experiments were conducted and to provide an alternative tool for this evaluation, High Resolution Computed Tomography (HRCT-Scan) was also used. The results showed positive correlation of clay with maximum dry bulk density, but it was found that sand and silt were more positively correlated with optimum moisture content than clay. These results indicated that in this region, the soils are most susceptible to compaction and harvesting traffic make them compacted. The maximum compaction occurred in the first layer (0-20 cm depth) and minimum or no compaction happened in the layer, beyond the 60 cm depth. These results also showed that subsoiling the soil can improve the soil physical properties. Furthermore, CT-Scan results indicated that compaction can be treated by subsoiling and soil physical properties can be improved. This type of managing soil compaction has been used in the field and high harvested sugarcane (Saccharum officinarum) yield indicates that it is a successful operation.

  7. 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

  8. 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.

  9. Effects of soil compaction on the relationships between nematodes, grass production and soil physical properties

    NARCIS (Netherlands)

    Bouwman, L.A.; Arts, W.B.M.

    2000-01-01

    As farm machinery has become heavier, concern has grown about its direct effects on soil physical conditions and its indirect effects on crop yields and soil biota. To study the relationships between these parameters, non-grazed temporary grassland plots on a loamy sand soil were subjected to full-w

  10. Modeling of permeability and compaction characteristics of soils using evolutionary polynomial regression

    Science.gov (United States)

    Ahangar-Asr, A.; Faramarzi, A.; Mottaghifard, N.; Javadi, A. A.

    2011-11-01

    This paper presents a new approach, based on evolutionary polynomial regression (EPR), for prediction of permeability ( K), maximum dry density (MDD), and optimum moisture content (OMC) as functions of some physical properties of soil. EPR is a data-driven method based on evolutionary computing aimed to search for polynomial structures representing a system. In this technique, a combination of the genetic algorithm (GA) and the least-squares method is used to find feasible structures and the appropriate parameters of those structures. EPR models are developed based on results from a series of classification, compaction, and permeability tests from the literature. The tests included standard Proctor tests, constant head permeability tests, and falling head permeability tests conducted on soils made of four components, bentonite, limestone dust, sand, and gravel, mixed in different proportions. The results of the EPR model predictions are compared with those of a neural network model, a correlation equation from the literature, and the experimental data. Comparison of the results shows that the proposed models are highly accurate and robust in predicting permeability and compaction characteristics of soils. Results from sensitivity analysis indicate that the models trained from experimental data have been able to capture many physical relationships between soil parameters. The proposed models are also able to represent the degree to which individual contributing parameters affect the maximum dry density, optimum moisture content, and permeability.

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

    Science.gov (United States)

    Ruiz, Siul; Or, Dani; Schymanski, Stanislaus J

    2015-01-01

    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. PMID:26087130

  12. 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.

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

    Science.gov (United States)

    Ruiz, Siul; Or, Dani; Schymanski, Stanislaus J

    2015-01-01

    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.

  14. 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

  15. An in-situ soil structure characterization methodology for measuring soil compaction

    Science.gov (United States)

    Dobos, Endre; Kriston, András; Juhász, András; Sulyok, Dénes

    2016-04-01

    The agricultural cultivation has several direct and indirect effects on the soil properties, among which the soil structure degradation is the best known and most detectable one. Soil structure degradation leads to several water and nutrient management problems, which reduce the efficiency of agricultural production. There are several innovative technological approaches aiming to reduce these negative impacts on the soil structure. The tests, validation and optimization of these methods require an adequate technology to measure the impacts on the complex soil system. This study aims to develop an in-situ soil structure and root development testing methodology, which can be used in field experiments and which allows one to follow the real time changes in the soil structure - evolution / degradation and its quantitative characterization. The method is adapted from remote sensing image processing technology. A specifically transformed A/4 size scanner is placed into the soil into a safe depth that cannot be reached by the agrotechnical treatments. Only the scanner USB cable comes to the surface to allow the image acquisition without any soil disturbance. Several images from the same place can be taken throughout the vegetation season to follow the soil consolidation and structure development after the last tillage treatment for the seedbed preparation. The scanned image of the soil profile is classified using supervised image classification, namely the maximum likelihood classification algorithm. The resulting image has two principal classes, soil matrix and pore space and other complementary classes to cover the occurring thematic classes, like roots, stones. The calculated data is calibrated with filed sampled porosity data. As the scanner is buried under the soil with no changes in light conditions, the image processing can be automated for better temporal comparison. Besides the total porosity each pore size fractions and their distributions can be calculated for

  16. The impact of site preparation for biofuel and sawtimber production on soil compaction and long-term soil productivity

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, Z.H.; Sucre, E.B. [Weyerhaeuser NR Co., Vanceboro, NC (United States)

    2010-07-01

    Research into renewable fuel sources has increased as a result of increasing global concerns over carbon dioxide (CO{sub 2}) emissions. This study assessed that potential effects of concurrent biofuel and high quality wood product production in forests along the lower coastal plain of North Carolina. The effects of intercropping and biomass management on site productivity and sustainability were investigated on loblolly pine plantations; loblolly pine and switchgrass; and loblolly pines with flat-planted pine trees planted between crop tree beds. Stands of switchgrass only were also investigated. The treatments were established on 0.81 hectare plots and replicated 4 times. The impacts of various non-traditional land management approaches on soil productivity and sustainability were assessed, as well as the site preparations needed to develop a dual crop system. The study showed no significant differences in soil compaction before and after the treatments were installed. Average soil resistance across all treatments at the soil surface was 201 kPa. Soil resistance increased to 1539 kPa and 1923 kPa at depths of 15 and 30 cm. The study indicated that dual crop systems and practices for biofuel and timber production are both economically feasible and environmentally sustainable.

  17. Effects of tree-length timber skidding on soil compaction in the skid trail in Hyrcanian forests

    Directory of Open Access Journals (Sweden)

    Meghdad Jourgholami

    2014-08-01

    Full Text Available Aim of study: The study was conducted to examine impact of skidding traffic, trail slope, traffic frequency, and soil depth on the soil bulk density.Area of study: This study was carried out in the Kheyrud Forest in Hyrcanian forest, Iran.Material and methods: The level of soil compaction at eight levels of traffic (1, 4, 8, 10, 15, 20, 25, and 30 passes, four levels of skid trail slopes (0, 10, -10, and -20% and three soil depth (5, 15, 25 cm were applied in three replicates consequently. Bulk densities were measured on the undisturbed surface (control and within the tracks. Timbers were extracted in the tree-length logging method using rubber-tired skidder (Timberjack 450 C.Main results: About 5.2% of total area of harvesting unit were disturbed and compacted. Uphill skidding increases compaction more than downhill skidding. In the four different slopes, the highest increasing of the bulk density was occurred during the first few passes of skidder, although the bulk density continued to increase in amount and depth with the number of passes. The increases in bulk density were still important at the maximum sampling depth of 20-30 cm.Research highlights: The results indicated that slope steepness had a strong effect on the soil physical properties and soil disturbance. Designated skid trails should be used to minimize the influence on the forest soil.Key words: soil compaction; tree-length logging method; rubber-tired skidder; Hyrcanian forest.

  18. Intrinsic degradation of volatile fatty acids in laboratory-compacted clayey soil

    Science.gov (United States)

    Hrapovic, L.; Rowe, R. K.

    2002-10-01

    Volatile fatty acids (VFAs) represent the major organic constituent of landfill leachate and provide the greatest potential for leachate induced organic contamination of groundwater (e.g. as represented by an increase in the concentration of dissolved organic carbon and chemical oxygen demand). Long-term diffusion tests were performed for laboratory-compacted clayey soil plugs exposed to continuous supply of synthetic leachate containing VFAs. Significant microbial activity developed upon exposure of the soil's indigenous microorganisms to these degradable contaminants. The growth of heterotrophic aerobic bacteria (HAB, which include facultative anaerobes), sulfate reducing bacteria (SRB) and methanogenic bacteria carrying out fermentation and mineralization of the VFAs became evident after 30-50 days of testing. The maximum microbial counts of (2-8)×10 8 and (0.1-1)×10 8 cfu/g for HAB and SRB were localized in the soil layer at the interface with the source of organic and inorganic nutrients. Regardless of this rapid growth in microbial population, the VFA consumption was small and measurable only after a lag of 140-180 days. It is considered that this lag of otherwise readily degradable organic compounds (such as VFAs) persisted due to a combination of the effects of a high initial concentration of these acids (2.4 g/l as dissolved organic carbon, DOC) applied to carbon starved soil microorganisms and the small pore size of the compacted clay. Once the significant amounts of gas were generated from fermentation, conditions developed for improved mass transport and exchange of the nutrients and bacteria and the outcome of the intrinsic degradation was more apparent. The breakdown of VFAs that followed after the lag was localized near the top of the soil and was characterized by a short half-life of 0.75-5 days for DOC (total VFAs as dissolved organic carbon).

  19. Simulation analysis on influencing factors of reclamation soil compaction in mechanical compaction process%机械压实过程中复垦土壤紧实度影响因素的模拟分析

    Institute of Scientific and Technical Information of China (English)

    刘宁; 李新举; 郭斌; 闵祥羽

    2014-01-01

    Soil compaction resulted from mechanical rolling is one of the major problems in land reclamation. There are a lot of factors that influence soil compaction apart from soil properties, and also mechanical pressure, soil layer, and times of compaction etc. Based on the statistical theory, this article focused on a 2×5×4 mixed experimental design and established a simulation experimental area that employed a heavy punch to simulate the two compact machineries for respectively once, three times, five times, seven times, and nine times. Each fall depth for every compact punch on the soil would be measured. Afterwards, the soil compaction gauge was used to measure the soil compaction changes in different layers. At last, variance analysis in SPSS was conducted and a comparison of random pairs, with the intention of finding influential factors of soil density in the mechanical compaction process and the varied range and preconditions of each factor. The results derived were as follows:(1) A size increase of the compact machinery roller wheels can effectively reduce mechanical compaction on the soil. Since the ground contact area was relatively small when the wheel dumper ran, soil compaction was increasingly seriously affected in the land reclamation process. In the process of machinery compaction, soil fall depth reflects the soil compaction degree, to some extent, and can serve common farmland cultivation as one of the indicators for a preliminary judgment on soil compaction. (2) Compact machinery, soil layer, and times of compaction are all notable factors influencing soil compaction, all of whose contribution rate is highly above random error. The interactive effect, especially between the compact machinery and times of compaction, had a remarkable and profound effect on soil compaction. (3) Different compact machineries of varied weights and ground contact areas would lead to different compaction effects. The dump truck crushed down into 30cm on the upper layer

  20. A finite strain elastoplastic constitutive model for unsaturated soils incorporating mechanisms of compaction and hydraulic collapse

    Directory of Open Access Journals (Sweden)

    Nakamura Keita

    2016-01-01

    Full Text Available Although the deformation of unsaturated soils has usually been described based on simple infinitesimal theory, simulation methods based on the rational framework of finite strain theory are attracting attention especially when solving geotechnical problems such as slope failure induced by heavy rain in which large a deformation is expected. The purpose of this study is to reformulate an existing constitutive model for unsaturated soils (Kikumoto et al., 2010 on the basis of finite strain theory. The proposed model is based on a critical state soil model, modified Cam-clay, implementing a hyperelastic model and a bilogarithmic lnv-lnP’ (v, specific volume; P’, effective mean Kirchhoff stress relation for a finite strain. The model is incorporated with a soil water characteristic curve based on the van Genuchten model (1990 modified to be able to consider the effect of deformation of solid matrices. The key points of this model in describing the characteristics of unsaturated soils are as follows: (1 the movement of the normal consolidation line in lnv-lnP’ resulted from the degree of saturation (Q, deviatoric Kirchhoff stress, and (2 the effect of specific volume on a water retention curve. Applicability of the model is shown through element simulations of compaction and successive soaking behavior.

  1. Influence of Soil Compaction and Drought on the Growth,Photosynthesis and Carbohydrates in Fugi/M.9EMLA Apple Plants

    Institute of Scientific and Technical Information of China (English)

    YAO Yun-cong; John G Streeter; David C Ferree

    2003-01-01

    Greenhouse-grown 1-year-old potted M.9EMLA apple trees (Malus pumila Borkh) were subjected to the soil compaction and, after growing under compacted or non-compacted conditions for 6 weeks, were subjected to drought stress by withholding water for an additional six-week period. Soil compaction and drought stress significantly reduced plant height, number of leaves, and leaf area. Although drought significantly inhibited photosynthesis and transpiration, compaction only depressed transpiration. Furthermore, the effects of drought on plant growth, photosynthesis and transpiration were much greater than the effects of compaction. The rate of water loss from compacted plants was lower than the rate from non-compacted controls and this may explain the insignificant impact of compaction on photosynthesis. Sorbitol, glucose, and fructose concentrations increased over time during the drought stress period whereas sucrose concentration declined. In well-watered controls, sucrose concentration was much higher in leaves of compacted plants than in the leaves on non-compacted controls. For most of the sampling dates the leaf sorbitol concentration was lower in leaves on plants growing in compacted soil than in the leaves of those of the non-compacted controls. Although interactions between the effects of compaction and drought were highly significant for plant growth variables during the onset of drought, interactive effects on photosynthesis, transpiration, relative water content and carbohydrate variables were inconsistent. Compaction and drought both have major effects on apple plants and the interactions between these two stresses are complex.

  2. Effect of Compaction Energy on Engineering Properties of Fly Ash –Granite Dust Stabilized Expansive Soil

    Directory of Open Access Journals (Sweden)

    Akshaya Kumar Sabat

    2015-10-01

    Full Text Available The effects of compaction energy on engineering properties of an expansive soil stabilized with optimum percentage of fly ash-granite dust have been discussed in this paper. Expansive soil stabilized with optimum percentage of fly ash-granite dust was compacted with five compaction energy levels. Maximum dry density and optimum moisture content corresponding to each energy level were determined. Based on these maximum dry density and optimum moisture content, samples were prepared for unconfined compressive strength, soaked California bearing ratio, hydraulic conductivity and swelling pressure tests. From the test results it is found that increase in compaction energy increased the maximum dry density, unconfined compressive strength, soaked California bearing ratio and swelling pressure, and decreased the optimum moisture content and hydraulic conductivity.

  3. Absorption of primary macronutrients and soybean growth at different compactation densities and moisture levels in a silt loam soil

    Directory of Open Access Journals (Sweden)

    Romano Roberto Valicheski

    2016-04-01

    Full Text Available ABSTRACT Soybean cultivation is increasing rapidly in the region of Alto Vale do Itajaí, State of Santa Catarina, where there is a predominance of silt soils. The objective of this work was to evaluate the content of primary macronutrients in shoots and shoot and root vegetative growth of soybean (Glicine max L. Merrill grown in a silt-loam soil under different compactation densities and moisture levels. A randomized block design in a 4x4 factorial arrangement was used, with four compactation densities: 1.00; 1.20; 1.40 and 1.60 Mg m-3, and four soil moisture levels: 0.130; 0.160; 0.190 and 0.220 kg kg-1 and four replications. Each pot consisted of the overlapping of three 150-mm PVC rings, where soil was maintained in the higher and lower part of the pot with a density of 1.00 Mg m-3 and in the intermediate ring, the compactation densities were increased. Values of soil density higher than 120 Mg m-3 negatively affected N, P and K uptake by soybean plants, as well as the plant mass of the shoots and roots. The higher levels of soil moisture reduced the compaction effect and promoted better absorption of P and K.

  4. Development and Experimental Testing of a FEM Model for the Stress Distribution Analysis in Agricultural Soil due to Artificial Compaction

    Directory of Open Access Journals (Sweden)

    Sorin-Ştefan Biriş

    2009-03-01

    Full Text Available It is known that the compaction phenomenon of agricultural soil can be defined as an increase in its dry density, respectively as in reduction of its porosity, and it can result from any natural causes as: rainfall impact, soaking, internal water stress from soil, and other. An important role has the artificial compaction, which is generated by the contact with tyres or caterpillars of tractors and agricultural machines. In present, one of the most advanced methods for modelling the phenomenon of stresses propagation in agricultural soil is the Finite Element Method (FEM, which is a numerical method for obtaining approximate solutions of ordinary and partial differential equations of this distribution. In this paper, the soil has been idealised as an elastic-plastic material by Drucker- Prager yield criteria. This paper presents a model for prediction of the stress state in agricultural soil below agricultural tyres in the driving direction and perpendicular to the driving direction, which are different from one another, using the Finite Element Method. General model of analysis was created using FEM, which allows the analysis of equivalent stress distribution and the total displacements distribution in the soil volume, making evident both of the conditions in which the soil compaction is favour and of the study of graphic variation of equivalent stress and the study of shifting in the depth of the soil volume. Using an acquisition data system and pressure sensors, the theoretical model was experimentally checked in the laboratory.

  5. Non-invasive Observation of the Compacted Plough Pan Layer and Its Effect on Soil Water Regime

    Science.gov (United States)

    Jeřábek, J.; Zumr, D.

    2015-12-01

    A compaction of soils at agricultural areas is a known phenomenon influencing the water retention and runoff regimes. Nevertheless, an investigation of compacted soil layer position and (dis)continuity is complicated. Using of direct measurement methods is almost infeasible at larger areas due to excessive labour and cost demands of such an approach. Other disadvantage of direct methods is usually lack of continuous information, which may be desirable in some cases. The electrical resistivity tomography (ERT) is useful method for its relatively simple and non-invasive data acquisition and continuity of the measured data. However, reliability of the ERT measurement for exact plough pan delineation is still questionable. In this work we assessed the feasibility of the ERT to delineate the compacted soil layer. To do so, we compared soil electrical resistivity with soil penetration resistance. The field experiments took place at the experimental catchment in central part of the Czech Republic. Soil profile samples were taken to gain more complex information of soil physical characteristics possibly influencing the soil resistivity. All measurements were performed recurrently under different topsoil structure and soil saturation conditions. Classical methods of statistic and geo-statistis was used to evaluate the data. The effect of the compacted subsoil layer on soil water regime during heavy rainfall events was evaluated with the use of dual porosity numerical code S1D. Due to comparatively lower ratio of preferential pathways and macropores in the subsoil the percolating water accumulate on the plough pan causing local flooding of the fields or lateral shallow subsurface runoff. The research was performed within the framework of a postdoctoral project granted by Czech Science Foundation No. 13-20388P.

  6. 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

    continuum-like stress transmission patterns were observed. We found that continuum stress transmission patterns were well simulated with models based on the elasticity theory (e.g., Boussinesq, 1885) compared to discrete stress transmission patterns. The soil pore structure was affected by increasing......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...... 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...

  7. Root cap removal increases root penetration resistance in maize (Zea mays L).

    Science.gov (United States)

    Iijima, Morio; Higuchi, Toshifumi; Barlow, Peter W; Bengough, A Glyn

    2003-09-01

    The root cap assists the passage of the root through soil by means of its slimy mucilage secretion and by the sloughing of its outer cells. The root penetration resistance of decapped primary roots of maize (Zea mays L. cv. Mephisto) was compared with that of intact roots in loose (dry bulk density 1.0 g cm-3; penetration resistance 0.06 MPa) and compact soil (1.4 g cm-3; penetration resistance 1.0 MPa), to evaluate the contribution of the cap to decreasing the impedance to root growth. Root elongation rate and diameter were the same for decapped and intact roots when the plants were grown in loose soil. In compacted soil, however, the elongation rate of decapped roots was only about half that of intact roots, whilst the diameter was 30% larger. Root penetration resistances of intact and decapped seminal axis were 0.31 and 0.52 MPa, respectively, when the roots were grown in compacted soil. These results indicated that the presence of a root cap alleviates much of the mechanical impedance to root penetration, and enables roots to grow faster in compacted soils.

  8. 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

    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...... in subsoil. A randomized block design trial at two sites on a well-structured clay soil in central Sweden was established. Plots with two levels of compaction were created at both sites, in the following referred to as trafficked and control. The trafficked treatment was created by 4 passes track......-by-track with a three-axle dumper with a maximum wheel load of 5.8 Mg. After one year, undisturbed soil columns (20 cm height 20 cm diameter) from both trafficked and control plots at a depth of 30–50 cm were sampled. The columns were analyzed using X-ray CT imaging, together with measures of the degree of preferential...

  9. Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

    Science.gov (United States)

    Miller, J J; Bremer, E; Curtis, T

    2016-07-01

    Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding. PMID:27380095

  10. Traffic effect on soil compaction and yields of wheat in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Tolon-Becerra, A.; Lastra-Bravo, X. B.; Botta, G. F.; Tourn, M.; Linares, P.; Ressia, M.; Balbuena, R.

    2011-07-01

    The general objective of this paper was to quantify the changes in the physical properties of an Aridisol soil and the effect on wheat yield due to agricultural tractors traffic in the Velez Blanco District, Almeria Spain. Parameters measured were cone index (CI) in the 0-600 mm depth profile, bulk density (BD) and rut depth; the variable wheat yields (WY) was measured too. The traffic treatments applied were: 0 (control plot), 1, 3, 5, and 7 tractor passes in the same tracks. Each experimental plot was trafficked with two tractors, one light (60 kN) and one heavy (80 kN). In topsoil (0-200 mm), up to five passes of the heavy (HT) and light tractors (LT), as in one and three passes, the BD and CI values responded to the ground pressure being higher in absolute value for LT. For the 200 to 400 mm depth range HT caused higher CI (1,570 to 2,200 kPa) and BD (1.38 to 1.68 Mg m{sup -}3) values than LT. Eight months later, WY was evaluated in tractors track areas and decreases in the range of 18-38%, were measured. For seven passes the applications of total loads of 80 and 60 kN increased BD up to 1.5 Mg m{sup -}3 at depths of 200-600 mm. Although soil had high bulk density prior to traffic treatments, a significant increment of subsoil compaction still occurred due to the high traffic intensities applied. (Author) 28 refs.

  11. Compact, Lightweight Dual-Frequency Microstrip Antenna Feed for Future Soil Moisture and Sea Surface Salinity Missions

    Science.gov (United States)

    Yueh, Simon; Wilson, William J.; Njoku, Eni; Dinardo, Steve; Hunter, Don; Rahmat-Samii, Yahya; Kona, Keerti S.; Manteghi, Majid

    2006-01-01

    The development of a compact, lightweight, dual-frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described. The design is based on the microstrip stacked-patch array (MSPA) to be used to feed a large lightweight deployable rotating mesh antenna for spaceborne L-band (approx.1 GHz) passive and active sensing systems. The design features will also enable applications to airborne soil moisture and salinity remote sensing sensors operating on small aircrafts. This paper describes the design of stacked patch elements and 16-element array configuration. The results from the return loss, antenna pattern measurements and sky tests are also described.

  12. Desiccation-Induced Volumetric Shrinkage of Compacted Metakaolin-Treated Black Cotton Soil for a Hydraulic Barriers System

    Science.gov (United States)

    Moses, George; Peter, Oriola F. O.; Osinubi, Kolawole J.

    2016-03-01

    Black cotton soil treated with up to 24% metakaolin (MCL) content was prepared by molding water contents of -2, 0, 2, 4 and 6% of optimum moisture content (OMC) and compacted with British Standard Light (BSL) and West African Standard (WAS) or `Intermediate' energies. The specimens were extruded from the compaction molds and allowed to air dry in a laboratory in order to assess the effect of desiccation-induced shrinkage on the compacted mix for use as a hydraulic barrier in a waste containment application. The results recorded show that the volumetric shrinkage strain (VSS) values were large within the first 10 days of drying; the VSS values increased with a higher molding of the water content, relative to the OMC. The VSS generally increased with a higher initial degree of saturation for the two compactive efforts, irrespective of the level of MCL treatment. Generally, the VSS decreased with an increasing MCL content. Only specimens treated with a minimum 20% MCL content and compacted with the WAS energy satisfied the regulatory maximum VSS of 4% for use as a hydraulic barrier.

  13. 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

  14. Conversió de fitxers ATLAS a IC-CAP per a la obtenció del model compacte de transistors

    OpenAIRE

    Ferrés Terradellas, Daniel

    2010-01-01

    El transistor bipolar, com altres dispositius semiconductors, utilitza models matemàtics per simular el seu comportament elèctric. El model matemàtic, o model compacte del dispositiu semiconductor, equival a un circuit electrònic amb un conjunt de paràmetres que emula el comportament del dispositiu. Per tant, la obtenció d’aquest model, és clau en el disseny de circuits que incorporin aquests dispositius. El dispositiu bipolar amb el que s’ha treballat en aquest projecte, és...

  15. 考虑饱和度的压实填土抗剪强度研究%Research on shear strength of compacted soils considering saturation degree

    Institute of Scientific and Technical Information of China (English)

    骆以道

    2011-01-01

    压实填土一般为典型的非饱和土,广泛存在于各类工程中,其物理力学性质受填土含水状态的影响.因基质吸力测量困难,非饱和土强度理论难以在压实填土工程中应用.研究含水状态变化对压实土抗剪强度影响的大小,寻找一种简化实用的非饱和压实土抗剪强度确定方法.从非饱和土理论出发,对含水状态影响压实土抗剪强度的机制进行了分析,重新整理并分析了5种压实土的非饱和三轴试验结果,对一些压实土工程资料中的直剪试验强度指标进行了收集和整理.分析表明,基质吸力对压实填土抗剪强度的贡献占有相当大的比例;含水率变化对压实填土抗剪强度的影响是非常显著和不容忽视的.工程资料中压实土饱和度对数值与黏聚力指标有良好的线性相关关系,提出了一个考虑饱和度影响的压实填土抗剪强度简易计算方法.%Compacted soil, which widely exists in many sorts of engineering projects, is commonly unsaturated soil; and its physico-mechanical characteristics are influenced by soil moisture. Because of the difficulty in matric suction measurement, it is hard to apply the unsaturated soil strength theory to compacted soil projects. This paper aims to research how much influence on shear strength of compacted soil when soil moisture varies, and tries to find an easy and useful way in determining the shear strength of unsaturated compacted soils. Research works start from the theory of unsaturated soil, and the mechanism, with which soil moisture affects shear strength of compacted soil, is analyzed. Triaxial shear test results of five sorts of unsaturated compacted soils are rearranged and analyzed; and strength parameters of direct shear test are collected and arranged from data of some filled and compacted soil projects. Analysis shows that matric suction contributes a considerable portion of shear strength in the compacted soils; and the influence

  16. 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

  17. Hydromechanical behavior of a quasi-saturated compacted soils on drying-wetting paths-experimental and numerical approaches

    Directory of Open Access Journals (Sweden)

    Andriantrehina Soanarivo Rinah

    2016-01-01

    Full Text Available This paper presents an experimental and numerical investigation funded by the French National Project “Terredurable”, which is devoted to the study of soils in quasi-saturated state. The experimental study is focused on the behavior of compacted soils on drying-wetting paths and the macroscopic effect of the drying path on shrinkage and cracking. Furthermore, a protocol for image analysis of crack in drying tests was developed. Two approaches are used for the measurement of surface strains and identification of the ultimate stress before the formation of the first crack, using VIC-2D software, and for the monitoring of crack evolution, using ImageJ software. The aim of the numerical approach is to reproduce the drying experiments with a finite difference code (FLAC 3D, in order to understand the stress conditions that can explain crack initiation, without modeling the crack formation itself.

  18. 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

  19. Long term chemo-hydro-mechanical behavior of compacted soil bentonite polymer complex submitted to synthetic leachate.

    Science.gov (United States)

    Razakamanantsoa, Andry Rico; Djeran-Maigre, Irini

    2016-07-01

    An experimental program is carried out to investigate the long term hydro-mechanical behavior correlated with chemical one of compacted soils with low concentration of Ca-bentonite and Ca-bentonite polymer mixture. The effect of prehydration on the hydraulic performance is compared to the polymer adding effect. All specimens are submitted to synthetic leachate (LS) under different permeation conditions. Several issues are studied: mechanical stability, hydraulic performance, chemical exchange of cations validated with microstructure observations. Scanning Electron Microscope (SEM) observations demonstrate two distinct behaviors: dispersive for Bentonite (B) and B with Polymer P1 (BP1) and flocculated for B with Polymer P2 (BP2). Direct shear tests show that bentonite adding increases the Soil (S) cohesion and decreases the friction angle. Polymer adding behaves similarly by maintaining the soil cohesion and increasing the friction angle. Hydraulic conductivity of prehydrated soil bentonite (SB) and direct permeation of polymer added soil bentonite are studied (SBP1 and SBP2). Hydraulic test duration are in range of 45days to 556days long. Prehydration allows to delay the aggressive effect of the LS in short term but seems to increase its negative effect on the hydraulic conductivity value in long term exposure. SB and SBP1 behave similarly and seem to act in the long term as a granular filler effect. SBP2 presents positive results comparing to the other mixtures: it maintains the hydraulic conductivity and the chemical resistance. Chemical analysis confirms that all specimens are subjected to Na(+) dissolution and Ca(2+) retention which are more pronounced for prehydrated specimen. The short term effect of prehydration and the positive effect of SBP2 are also confirmed. PMID:27156365

  20. Effects of physical properties on electrical conductivity of compacted lateritic soil

    Institute of Scientific and Technical Information of China (English)

    Wei Bai; Lingwei Kong; Aiguo Guo

    2013-01-01

    Natural soils of various types have different electrical properties due to the composition, structure, water content, and temperature. In order to investigate the electrical properties of lateritic soil, electrical con-ductivity experiments have been conducted on a self-developed testing device. Test results show that the electrical conductivity of laterite increases with the increase of water content, degree of saturation and dry density. When the water content is below the optimum water content, the electrical conductivity of soils increases nonlinearly and the variation rate increases dramatically. However, when the water content, degree of saturation, or dry density increases to a certain value, the electrical conductivity tends to be a constant. In addition, soil electrical conductivity increases with the increase of temperature, and it is observed that the electrical conductivity decreases with the increase of the number of wetting-drying cycles.

  1. 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)

  2. Inter-relation between soybean yield and soil compaction under degraded pasture in Brazilian Savannah

    Directory of Open Access Journals (Sweden)

    Rienni de Paula Queiroz

    2011-10-01

    Full Text Available The Cerrado (Brazilian Savannah plays an important economic and financial role in the nation, since the pastures of this biome feed cattle for half of the domestic bovine meat productivity, and its agricultural fields produce a third of the country's grain. The variability and spatial dependence between the soil physical attributes and soybean yield were evaluated in a crop rotation planted on a degraded brachiaria pasture, on a dystroferric Red Latosol of an experimental farm of the State University of São Paulo (UNESP, in the 2005/2006 growing season. The linear and spatial correlations between these attributes were also studied, to determine conditions that would allow increased agricultural productivity. In the above pasture area, a grid was installed with 124 plots, spaced 10.0 x 10.0 m and 5.0 x 5.0 m apart, in a total area of 7,500 m². From the linear and spatial point of view, the high grain yield can be explained by the number of grains per plant and soil macroporosity. The high variability observed for most soil properties indicated that the crop - livestock integration system results in environmental heterogeneity of the soil.

  3. COSmic-ray soil moisture observing system (COSMOS) in grazing-cap fields at El Reno, Oklahoma

    Science.gov (United States)

    Soil water content (SWC), especially over large areas, is an important variable needed by hydrological, meteorological, climatological, agricultural, and environmental scientists. Point measurements of SWC are impractical to obtain over extensive areas; thus, methods that provide real-time, hectare...

  4. 轻量土击实密度模型与工程特性%Model for compaction density and engineering properties of light weight soil

    Institute of Scientific and Technical Information of China (English)

    侯天顺

    2014-01-01

    In order to study the compaction mechanism of soft inclusion soil, and to guide the prescription design and compaction construction of light weight soil, a model for compaction density is established based on material composition and the physical essence of soil compaction. It is found that the predicted value is nearly close to the measured wet density. The absolute error is only 0.003~0.051 g/cm3, and the relative error is only 0.282%~5.267%. It is proved that the model for compaction density can predict exactly the wet density of mixed soil under different compaction conditions. The compression ratio of EPS beads and the wet density of mixed soil increase with the increase of compaction times, and the increase trend becomes slow gradually, and the void ratio of mixed soil decreases with the increase of compaction times. Under compaction conditions, the increase of wet density of light weight soil is accomplished by both the deceasing pore of soil and the plastic compression of EPS beads soft inclusion. Being similar to those of light weight soil with sand, the wet density and unconfined compressive strength of light weight soil with clay increase with the increasing compaction times. When compaction time n=25, the compression ratio range of EPS beads is 6.13%~11.51%;when n=94, the compression ratio range is 12.80%~14.87%. It is proved that the compaction times and energy which the standard specifies are fit for the compaction of mixed soil, and will not destroy the EPS beads. Considering that the measuring process of the parameters for the model for compaction density is complex, according to the practical engineering situation, it is supposed that the water content keeps the same during the compaction process, and the holes between soil and EPS beads after compaction are close to 0. The simplified model for compaction density is put forward, and the fact that the simplified model can be fit for the practical projects completely is proved.%为了探索软夹杂

  5. 土和灰土挤密桩处理软土地基研究%Study on Treatment of Soft soil Foundation Soil Compaction Pile and Lime-soil

    Institute of Scientific and Technical Information of China (English)

    王智轶; 王志铎

    2013-01-01

    Collapsible loess, plain fill and miscellaneous fill foundation of above the underground water level squeeze com-pacted pile in the soil and lime soil, using proper construction processes, to ensure that the quality of the project, the bearing capacity of soft soil foundation has been effectively improved.%本文对土和灰土挤密桩处理地下水位以上的湿陷性黄土、素填土和杂填土等地基进行研究,采用适当的施工工艺,确保了工程质量,软土地基的承载力得到了有效的改善。

  6. Burial trench dynamic compaction demonstration at a humid site

    International Nuclear Information System (INIS)

    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 m3 trench contained about 80 Ci of mixed radionuclides, mostly 90Sr, in 25 m3 of waste consisting of contaminated equipment, dry solids, and demolition debris. Prior to compaction, a total trench void space of 79 m3 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/m2) method to collapse trench void space, thereby hastening subsidence and stabilizing the land surface. 15 refs., 10 figs., 3 tabs

  7. Death cap

    DEFF Research Database (Denmark)

    Rudbæk, Torsten R; Kofoed, Pernille Bouteloup; Bove, Jeppe;

    2014-01-01

    Death cap (Amanita phalloides) is commonly found and is one of the five most toxic fungi in Denmark. Toxicity is due to amatoxin, and poisoning is a serious medical condition, causing organ failure with potential fatal outcome. Acknowledgement and clarification of exposure, symptomatic and focused...... treatment is of primary importance. No data from randomised, controlled trials on management exists, and there is not international consensus on treatment regime. We present amatoxin-case contacts to the Danish Poison Centre from 2006-2012 and summarize current knowledge and Danish recommendations...

  8. Soil compaction due to forest harvest operations Compactação do solo em conseqüência das operações de colheita florestal

    Directory of Open Access Journals (Sweden)

    Moacir de Souza Dias Junior

    2007-02-01

    Full Text Available The objective of this work was to determine, through the use of the bearing capacity model, the traffic effects of the forest harvest operations on the preconsolidation pressure (sigmap, during one cycle of the eucalyptus plantation. The work was conducted using undisturbed soil samples, collected at the surface of the A horizon and in the top of the B horizon of an Udult (PA, Aquox (FX and Udox (LA soils. The undisturbed soil samples were used in the uniaxial compression tests. The soil sampling was done before and after the harvest operations. The operations performed with the Forwarder caused greater soil compaction than the ones done with the Feller Büncher and Harvester. The percentage of soil samples, in the region with additional soil compaction, indicated that the Udult was the soil class more susceptible to soil compaction, followed by the Aquox and Udox. Despite Udult is the more susceptible to soil compaction, the regeneration of the soil structure in this soil class was more efficient than in Aquox. The percentage of soil samples with sigmap values in the region with additional soil compaction in 1996, 1998 and 2004, after harvest operations, indicated a sustainable forest exploration in this period.O objetivo deste trabalho foi determinar, pelo uso do modelo de capacidade de suporte de carga, o efeito do tráfego das operações de colheita florestal na pressão de preconsolidação (sigmap, durante um ciclo do eucaliptus. O trabalho foi realizado com amostras indeformadas, coletadas na superfície do horizonte A e no topo do horizonte B de um Argissolo Amarelo, de um Plintossolo e de um Latossolo Amarelo. As amostras indeformadas foram usadas nos ensaios de compressão uniaxial. A amostragem foi realizada antes e depois das operações de colheita. As operações realizadas com o Forwarder causaram maior compactação do solo do que as operações realizadas com o Feller Büncher e o Harvester. A porcentagem de amostras de solo

  9. Aspectos da estrutura da raiz e do desenvolvimento de plantas de soja em solos compactados Root structural aspects and development of soybean in compacted soils

    Directory of Open Access Journals (Sweden)

    RACHEL BENETTI QUEIROZ-VOLTAN

    2000-05-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da compactação do solo na anatomia da raiz e no desenvolvimento de duas cultivares de soja (Glycine max (L. Merrill, IAC-8 e IAC-14, em vasos. O solo utilizado foi um Latossolo Roxo, tirado da camada superficial (0-200 mm. Os níveis de compactação consistiram de 0,95 (controle, 1,20, 1,35 e 1,50 kg L-1, e foram obtidos pela compactação de determinada massa de solo por prensa hidráulica, em cilindros de ferro. A compactação do solo não afetou a estrutura anatômica da raiz, em nenhuma das duas cultivares. Na cultivar IAC-8, o número de folhas, a altura das plantas e o peso da matéria seca da raiz e do caule diminuíram com o aumento da densidade do solo, e o comprimento da raiz aumentou. Na cultivar IAC-14, o número de folhas, a área foliar, o número de vagens, a altura das plantas, o peso da matéria seca da raiz, do caule e das folhas foram diminuindo à medida que aumentava a densidade do solo, embora nas densidades intermediárias (1,20 e 1,35 se tenha notado uma tendência de aumento naquelas variáveis. A produção de soja não foi afetada pela compactação do solo, com exceção do número de vagens da cultivar IAC-14, que apresentou diferenças em razão do tratamento. Os resultados sugerem que as duas cultivares podem ser bem adaptadas a solos compactados, nos níveis analisados.The present study aimed at evaluating the effect of soil compaction on the root anatomy and plant development of two soybean (Glycine max (L. Merrill cultivars, IAC-8 and IAC-14, in pots. A clayey soil collected, from a superficial (0-200 mm layer was used. The compaction levels consisted of 0.95 (control, 1.20, 1.35 and 1.50 kg L-1, which were obtained by compaction of some soil mass with a hydraulic press inside of iron cylinders. The soil compaction did not affect the anatomic structure of the roots, in any of the two cultivars. In the IAC-8, the leaf number, plant height and the dry matter of

  10. 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.

  11. SIMULATION OF THE FORCE INTERACTION OF THE SOIL COMPACTING DISK MOVING ALONG A RHEOLOGICAL BEAM THAT HAS DISTRIBUTED MASS

    Directory of Open Access Journals (Sweden)

    Pavlov Georgiy Vasil'evich

    2012-10-01

    Full Text Available The authors describe an original solution to the new problem of a soil compacting disk moving along a rheological beam (Kelvin model in the proposed paper. The motion of the mechanical system that is composed of a disk and a rheological beam is described by a hybrid system of differential equations consisting of an integral-differential equation that stands for the interaction of the beam with a moving disk and Lagrange equations describing the pattern of the disk motion. These equations are considered as equations of nonholonomic links. The problem is solved through the employment of simplifying prerequisites and by determining the operating condition of the disk. Condition of uniform and uniformly variable motions is considered as an opportunity to integrate the equation of beam vibrations regardless of the system of equations describing the disk motion pattern. The solution to the equation in partial derivatives is found through the employment of the Fourier method of separation of variables coupled with the Laplace integral transformation method. The solution to the problem of constrained vibrations was implemented as a series of homogenous problems with zero initial and boundary conditions. The equation describing changes in the time function is reduced to its standard form, and thereafter the solution is found through the employment of asymptotic methods. Disk motion stability is assessed through the employment of the first approximation method. The motion of the disk is stable. As a result of the analysis of patterns of dependencies between beam deformations and the time period, the conclusion of feasibility of a stable pattern of forced vibrations of a rheological beam, supported by a driving force and a variable friction force, caused by the slightly elastic field of the beam material, is made by the authors.

  12. 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

  13. 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. PMID:27254100

  14. 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.

    Directory of Open Access Journals (Sweden)

    Françoise Martz

    Full Text Available 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.

  15. 氯盐型弱盐渍土压实特性试验研究%Experimental Study on the Compaction Characteristics of Chloride-based Weak Saline Soil

    Institute of Scientific and Technical Information of China (English)

    陈荣涛; 刘军辉; 刘军勇

    2013-01-01

    In order to solve the technical problems of fine-grained weak saline soil subgrade compaction , this paper studied the compaction characteristics of the weak saline soil by experiment, determined the optimal vibration-compaction parameters, and compared with the compaction effect that relevant criterions proposed. The results show that vibration-compaction can make the soil fully compacted and compaction effect is better. Suggestion; it is best to adopt the vibration-compaction method to determine standard density and optimum water content.%为解决细粒弱盐渍土路堤压实的技术难题,通过试验,研究细粒弱盐渍土的压实特性,确定其最优的振动压实参数,并与相关规范提出的标准试验方法压实效果进行了对比.结果表明,振动压实可以使土体得到充分的压实,压实效果更好.建议:对于细粒弱盐渍土应采用振动压实方法确定其标准密度和最佳含水率.

  16. Laboratory experiment for rapid testing of soil compaction performance with DCP%DCP快速检测土体压实性能的室内试验

    Institute of Scientific and Technical Information of China (English)

    查旭东; 刘国才; 杨博

    2012-01-01

    为了评价动态圆锥贯入仪(DynamicConePenetrometer,简称DCP)快速检测土体压实性能的合理性,选取湖南省典型的红粘土填料,室内制作6种不同含水率和3种不同压实度的土体压实试件,采用DCP快速检测了土体贯入度.同时,还进行了PFWD动模量和浸水前后CBR对比试验.回归分析表明,贯入度与含水率和压实度之间呈显著的多元线性关系,而与动模量和CBR值之间具有良好的幂函数关系.在压实度相同的情况下,当含水率小于最佳含水率时,贯入度随含水率的增加呈线性减小;而当含水率大于最佳含水率时,贯入度随含水率的增加呈线性增加.在含水率相同的条件下,贯入度随压实度增加呈线性减小,因此,DCP测试结果与土体压实质量和力学性能之间存在良好的相关性,可应用于土基压实性能的快速检测和评价。%In order to evaluate the rationality of rapid testing of soil compaction performance by using Dynamic Cone Penetrometer(DCP), the typical red-clay filler in Hunan Province was selected to make the soil compaction specimens with 6 kinds of different moisture con- tent and 3 kinds of different compactness in the laboratory. The soil penetrations were rap- idly tested with the DCP, and the PFWD dynamic moduli and the CBRs before and after soaking were also tested. The regression analysis show that there is a significant multivari- ate linear relation between penetrations and moisture contents with compactnesses, while there are the good power function relations between penetrations and dynamic moduli or CBRs. Among them, in the case of the same compactness, when the moisture content is smaller than the optimum moisture content, the penetration decreases linearly with the in- crease in the moisture content. On the contrary, when the moisture content is bigger than the optimum moisture content, the penetration increases linearly with the

  17. The principle of soil compaction by explosion and its experimental investigation%土体爆炸压密的原理及试验研究

    Institute of Scientific and Technical Information of China (English)

    潘强; 张继春; 郭学彬

    2011-01-01

    针对目前土体爆炸压密理论研究不够深入、施工中主要依靠工程经验确定爆炸参数的现状,建立了基于塑性力学和爆炸力学的土体爆炸压密模型,推得压密效果(压密范围、压密程度)与爆炸参数之间的关系式,并通过室外试验进行验证.在孔径为48 mm的炮孔中进行了不耦合系数分别为2.000、1.714、1.500、1.333、1.200、1.091和1.000的7组室外试验,通过测量爆炸前后的土体密度,进行理论和试验结果的对比分析.研究表明,不耦合装药时,压密效果的理论值随不耦合系数呈递增变化,而试验值呈先增后减的趋势,且在不耦合系数为约1.200时出现最大值;对于粘质粉土,压密效果较稳定,最大压密范围达到70 cm,最大压缩比为1.055;给出的爆炸后土体压密计算公式的准确性较高,相对误差小于6.00%,可用于工程实际.%Aimed at the status of explosion compaction, which was not thorough in theory study and relied mainly on engineering experience to determine blast parameters in constructions, a soil explosion compaction model was developed which was based on plastic mechanics and mechanics of explosion. The relations between compaction effects (compaction range, compaction degree) and explosive parameters were derived and verified by the field tests. The seven field tests were carried out in the holes with the diameter of 48 mm and the corresponding non-coupling coefficients were 2. 000, 1. 714, 1. 500, 1. 333, 1. 200, 1. 091 and 1. 000, respectively. And theoretical calculations and field test results were compared by measuring the soil density before and after the explosion. Investigated results indicate that in the case of non-coupling charge, the theoretical value of compaction effect increases with the increase of non-coupling coefficient, while the experimental data first increases and then decreases, arriving at the maximum for the non-coupling coefficient of around 1. 200. For the

  18. 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

  19. Mapping of the water ice content within the Martian surficial soil on the periphery of the retreating seasonal northern polar cap based on the TES and the OMEGA data

    Science.gov (United States)

    Kuzmin, R. O.; Zabalueva, E. V.; Evdokimova, N. A.; Christensen, P. R.

    2012-11-01

    Analysis of seasonal data from the Mars Global Surveyor Thermal Emission Spectrometer (TES) shows a significant increase in thermal inertia during autumn, winter and spring in the middle and high latitudes of Mars. At each stage of the northern seasonal polar cap's recession in spring a distinct high thermal inertia (HTI) annulus arises around the cap's edge. Within this annulus, we estimated and mapped the springtime water ice content in the daily thermal skin depth layer using spring and summer values of the thermal inertia in TES surface footprints. The results show that the average water content in the surface soil within the HTI annulus varies from ˜5 vol % at the early stages of the seasonal polar cap retreating (Ls = 340°-360°) to ˜1 vol % at later stages (Ls = 60°-70°). Maximum values of water ice content within the HTI annulus occur at Ls = 0°-20° (2-6 vol %) and Ls = 20°-40° (4-10 vol %). We analyzed the temporal and spatial relationship between the HTI annuli and the water ice (WI) annuli at the edge of the northern seasonal polar cap. The water ice within the WI annuli was mapped using a water ice spectral index (the absorption band depth at the 1.5 μm wavelength) derived from the OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) imaging spectrometer aboard the Mars Express spacecraft. Recent OMEGA observations show that the WI annuli formation arises only around the retreating northern seasonal polar cap, never around the retreating southern seasonal cap. For this reason our study is confined only to the northern hemisphere. The observed relationship between the HTI and WI annuli in the northern hemisphere of Mars indicates a close physical interdependence between these two phenomena. Our results confirm that the seasonal permafrost exposed by the retreating northern polar cap (within the HTI annuli) is actively involved today in the condensation and sublimation processes in the modern water cycle on Mars. The water

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

    Energy Technology Data Exchange (ETDEWEB)

    Khire, M.V. [GeoSyntec Consultants, Boca Raton, FL (United States); Benson, C.H.; Bosscher, P.J. [Univ. of Wisconsin, Madison, WI (United States)

    1997-12-31

    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.

  1. 模拟机械压实对黑土微团聚体组成及稳定性的影响%Effect of mechanical compaction on soil micro-aggregate composition and stability of black soil

    Institute of Scientific and Technical Information of China (English)

    卢倩倩; 王恩姮; 陈祥伟

    2015-01-01

    采用田间模拟机械压实的方法,通过对不同深度压实土壤水稳性微团聚体组成、平均质量比表面积、分形维数和分散系数等特征指标的测定、计算与分析,研究了机械压实对黑土区耕作土壤微团聚体组成及稳定性的影响。结果表明:0~20 cm表层土壤仅12次压实时平均质量比表面积、分形维数和分散系数显著高于对照(P<0.05);>20~40 cm亚表层土壤3次压实时平均质量比表面积、分形维数值显著降低,而12次压实时平均质量比表面积、分形维数和分散系数显著增加(P<0.05);>40~80 cm下层土壤,平均质量比表面积、分形维数和分散系数随压实次数的增加而增大,除3次和6次压实之间外,其他处理间差异均达显著水平(P<0.05)。可以认为,压实对黑土区耕作土壤团聚体组成及稳定性的影响表现为下层土壤的积累压实为主。%Aggregates are secondary particles formed through the combination of mineral particles glued by organic and inorganic substances. Soil compaction caused by mechanical tillage practices mainly affects its structure and function by the dispersing, braking, re-proportioning, re-arranging and re-combining aggregates. Although mechanical compaction was reported to reduce the proportion of soil water stable aggregate with size smaller than 0.25 mm, how further impact of mechanical compaction on composition and stability of soil micro-aggregate is still unknown. Comparing to the study of soil macro-aggregates, research on soil micro-aggregates can contribute to a better understanding of disperse strength and structural performance of primary aggregates under particular conditions. Based on the cropland soil in the typical black soil region of Northeast China, the influence of mechanical compaction on soil micro-aggregate composition and stability was studied by measuring and analyzing the soil micro-aggregate distribution

  2. Application of the Modified Compaction Material Model to the Analysis of Landmine Detonation in Soil with Various Degrees of Water Saturation

    Directory of Open Access Journals (Sweden)

    M. Grujicic

    2008-01-01

    Full Text Available A series of transient non-linear dynamics computational analyses of the explosion phenomena accompanying the detonation of a 100g C4 mine buried in sand to different depths is carried out using the software package AUTODYN. The mechanical response of sand under high deformation-rate conditions has been represented using the modified compaction material model developed in our recent work [1]. While the mechanical response of the other attendant materials (air, gaseous-detonation products and AISI 1006 mild steel is accounted for using the material models available in literature. The results obtained (specifically, the temporal evolution of the sand overburden shape and pressure at various locations in air above the detonation site were compared with their experimental counterparts for a (50wt%-sand/50wt.%-clay soil obtained recently by Foedinger [2]. The comparison revealed that the modified compaction material model for sand can account reasonably well for the magnitude, spatial distribution and the temporal evolution of the dynamic loads accompanying detonation of shallow-buried mines in soils with various clay and water contents.

  3. 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

  4. Microparticles, soil, derived chemical components and sea salt in the Hans Tausen Ice Cap ice core from Peary Island, North Greenland

    DEFF Research Database (Denmark)

    Steffensen, J.P.; Andersen, M.L.S; Stampe, Mia;

    2001-01-01

    Selected segments of the 344 m deep ice core from Hans Tausen ice cap in Peary Land, North Greenland have been stratigraphically analyzed for chemical impurities and insoluble microparticles (Dust). Two different components of the microparticles have been identified by their different sizedistrib......Selected segments of the 344 m deep ice core from Hans Tausen ice cap in Peary Land, North Greenland have been stratigraphically analyzed for chemical impurities and insoluble microparticles (Dust). Two different components of the microparticles have been identified by their different...

  5. Detecting Subgrade Compaction by Soil Density Gauge%SDG密度仪填土压实度检测试验

    Institute of Scientific and Technical Information of China (English)

    顾欢达; 杜智亮; 薛国强; 胡舜

    2012-01-01

    SDG密度仪是一种基于电磁学原理的密度检测仪,在用于路基填土压实度检测过程中,可进行现场压实填土密实度的快速无损检测,从而实现对现场填土压实质量的动态实时检验与控制.根据密度仪的特性实施现场与室内模拟试验,结果显示SDG密度仪具有良好的稳定性与可靠性,适合于黏性填土密度的快速无损检测,尤其是对于干密度为1.5 g/cm3以上的黏性填土显示良好的准确性与可靠性.%SDG is a density gauge based on electromagnetism principle. It could be used as a rapid nondestructive detecting method to detect subgrade compaction, which is helpful to real-time dynamic detecting of subgrade compaction. With site and laboratory tests, it cloud be concluded that the SDG is suitable for compaction detecting of clayey embankment with favorable stability and dependability, especially for the clayey embankment which dry density is near or above 1. 5g/cm3 .

  6. Influence of natural pozzolana and lime additives on the temporal variation of soil compaction and shear strength

    Institute of Scientific and Technical Information of China (English)

    Khelifa HARICHANE; Mohamed GHRICI; Hanifi MISSOUM

    2011-01-01

    Soil stabilization has been practiced for quite some time by adding mixtures,such as cement,lime and fly ash.The additives of lime (L),natural pozzolana (NP) or a combination of both were investigated here on the impact on the temporal variation of geotechnieal characteristics of two cohesive soils.Lime and natural pozzolana were added at the content of 0-8% and 0-20%,respectively.The soil specimens were cured for 1,7,28 and 90 days and then tested for shear strength.Our data show that a combination of lime with natural pozzolana causes the increase in the maximum dry density but the decrease in the optimum moisture content in the gray soil,and vice verse in the red soil.The shear stress of both cohesive soils stabilized with lime or with the combination of lime and natural pozzolana was found to increase with time.The cohesion and the internal friction angle in lime added samples were demonstrated to increase with time.The combination of lime with natural pozzolana exhibits a significant effect on the enhancement of the cohesion and the internal friction angle at later stages.The lime-natural pozzolana combination appears to produce higher shear parameters than lime or natural pozzolana used alone.

  7. Compactación potencial en dos suelos de la parte plana del Valle del Cauca Potential compaction in two soils of the flat portion of Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Edgar Madero-Morales

    2012-01-01

    Full Text Available Muestras de los primeros 20 cm de la superficie de dos suelos en CIAT-Palmira (Calciustol y Haplustol, vérticos mezclados francos isohipertérmicos con pendiente 0.5%, utilizados en coberturas tanto de bosque secundario como de cultivos diversos por más de cincuenta años consecutivos, fueron compactados en el aparato de Richards bajo dos condiciones de humedad (0.1 y 0.5 bar para comparar el punto de máxima compactación, y su influencia en la variación de la densidad aparente, la tasa de difusión de oxígeno, la porosidad de aireación, la conductividad hidráulica saturada y el módulo de ruptura. Se utilizó un diseño completamente al azar con arreglo factorial (dos suelos, por dos usos, por dos humedades con tres repeticiones. Para la separación de medias se utilizó la prueba de Duncan (P Samples from the top 20 cm of two soils in CIAT Palmira (Calciustoll and Haplustoll both vertic mixed loamy isohipertermic 0.5% slope used in both secondary forest cover and diverse crops for more than fifty consecutive years were compacted into the apparatus of Richards at two soil moisture contents (0.1 and 0.5 bar to compare the point of maximum soil compaction and its influence in the soil bulk density changes, rate of oxygen diffusion, aeration porosity, saturated hydraulic conductivity and rupture modulus. A complete randomized design with factorial arrangement was used which consisted of 2 soils x 2 uses x 2 soil moisture content x 3 repetitions and means separated by Duncan probe. The study showed that high soil content of O.M. do not always prevent soil degradation due to of agricultural machinery traffic at high soil moisture contents. Irrespective of soil use, siltier Calciustoll had a slightly more potential to compaction than Haplustol, and continued cultivation of the two soils has made them more susceptible to physical damage, because in wet condition compacted to the extreme and showing physical degradation which in practice may

  8. 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

  9. Hydraulic conductivity of compacted zeolites.

    Science.gov (United States)

    Oren, A Hakan; Ozdamar, Tuğçe

    2013-06-01

    Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

  10. 土壤改良剂对土壤紧实度及燕麦生长状况的影响%Effects of Soil Amendments on Soil Compaction and Growth Status of Oat

    Institute of Scientific and Technical Information of China (English)

    刘慧军; 刘景辉; 于健; 徐胜涛; 史吉刚

    2013-01-01

    Effects of different soil amendments on soil compaction and growth status of oat were studied.Results showed that all the soil amendments could reduce soil compaction; the order of them was potassium polyacrylate + potassium humate > polyacrylamide+potassium humate + potassium humate > potassium polyacrylate > polyacrylamide > potassium humate > CK; and soil compaction increased with the increase of soil depth.Soil amendments significantly increased plant height of oat and dry matter weight,and the height for the mixed use was higher than the single use.Grain yields under the amendment treatments were significantly higher than that under the control.The yields for potassium polyacrylate+ potassium humate and polyacrylamide+potassium humate were higher than that for the single use,being 4 694.2 and 4 566.9 kg/hm2 with the increments of 21.66% and 18.36%,respectively.Biological yield had the same effect as grain yield.The WUE under the amendment treatments was significantly higher than that under the control,and the WUE under mixed amendment was higher than that under other soil amendments.%研究了不同土壤改良剂(聚丙烯酸钾,聚丙烯酰胺,腐殖酸钾,聚丙烯酸钾十腐殖酸钾,聚丙烯酰胺十腐殖酸钾)对土壤紧实度及燕麦生长状况的影响.结果表明,各改良剂处理均能减小土壤紧实度,表现为:聚丙烯酸钾十腐殖酸钾>聚丙烯酰胺十腐殖酸钾>聚丙烯酸钾>聚丙烯酰胺>腐殖酸钾>对照,土壤紧实度均随着土壤深度增加而增加;土壤改良剂对燕麦株高和干物质量具有显著的提高作用,复配处理株高优于其他单施处理;土壤改良剂处理下籽粒产量均显著高于对照,其中聚丙烯酸钾十腐殖酸钾和聚丙烯酰胺十腐殖酸钾籽粒产量较其他处理高,分别为4 694.2和4 566.9 kg/hm2,较对照增产21.66%和18.36%,生物产量的增产效果表现同籽粒产量;各土壤改良剂处理水分利用效率均显

  11. Greenhouse gas emissions through cap barriers of landfills

    Energy Technology Data Exchange (ETDEWEB)

    Gourc, J.P.; Staub, M.; Simonin, R. [Grenoble Univ. (France). LTHE

    2009-07-01

    A study was conducted to examine the environmental impacts of landfill cap covers used to produce biogas. The sensitivity of the environmental performance of landfills on biogas collection and recovery systems as well as on cap cover characteristics was investigated. The study examined both soil and geosynthetic landfill cap covers used to maintain impermeability at landfill sites as well as to enable biogas recovery. Two types of cap cover were discussed: (1) a cover that enabled passive wetting of the landfill wastes through rainfall; and (2) an impermeable cap used to control leachate recirculation. The environmental impacts of both caps were discussed. The study showed that landfill cap covers are a significant means of sequestering greenhouse gases (GHGs).

  12. Research Progress on Response of Oil Crops to Soil Compaction Stress%油料作物对土壤紧实胁迫响应研究进展

    Institute of Scientific and Technical Information of China (English)

    沈浦; 冯昊; 罗盛; 王才斌; 陈殿绪

    2015-01-01

    Soil compaction stress threatens growth,yield and quality status of oil crops.The formation process of soil compaction stress and its harmful effects on soil fertility and oil crops were reviewed in this arti-cle.The effects of compaction stress on the four main factors including moisture,fertility,air and temperature of soil were also expounded,which could suppress the root development of rape,soybean,sesame,sunflower and castor,and further did harm to their growth characteristics and dry matter accumulation.The seed -un-derground crop such as peanut was more sensitive to soil compaction stress.Several important ways for impro-ving the soil compaction were proposed:(1)breaking soil compaction stress by tillage measures;(2)straw returning;(3)decreasing bulk density by adding sand to the clayey soil;(4)reducing soil compaction by ra-tional management of water and fertilizer;(5)breeding varieties with resistance to compaction stress.At last, the key research directions were put forward for oil crops resistant to soil compaction stress.%土壤紧实胁迫严重威胁油料作物的生长发育及产量和品质状况。本文综述了土壤紧实胁迫的发生及其对土壤肥力和油料作物的危害,阐明紧实胁迫下土壤“水、肥、气、热”受到的影响,由此抑制了油菜、大豆、芝麻、向日葵、蓖麻等作物根系发育,进而危及这些地上结实作物的生育特性及物质积累,并指明花生作为地下结实作物对土壤紧实胁迫的响应更为敏感。文章综述了改良油料作物土壤紧实胁迫的几个重要途径:(1)开展耕翻松土作业,打破土壤紧实;(2)秸秆还田;(3)掺沙改粘,降低土壤粘质性和容重;(4)合理水肥管理,减少板结发生;(5)选育高抗紧实胁迫的品种。最后,本文提出了油料作物应对土壤紧实胁迫需要加强的重点研究方向。

  13. 裂隙对压实膨胀土渗气性影响试验%The influences of fissure on gas permeability of the compacted expansive soil

    Institute of Scientific and Technical Information of China (English)

    袁俊平; 张锋; 王启贵; 丁巍

    2014-01-01

    A series of gas permeability tests were carried out in order to study its permeability on expansive soil with artificial fissures using self-designed and made apparatus. The results show that Darcy's law expresses the gas flow in the compacted expansive soil. When the soil sample is cut up completely, there is still a penetrated fissure within it that makes the permeability coefficient doubles. The fissures change the original gas flow path providing a convenient channel for it flows, consequently the “gas preferential flow” phenomenon could be observed in the fissured expansive soil. Comparing the theoretical analysis results of Darcy with that of non-Darcy, it is indicated that the non-Darcy theory is better than Darcy theory to analyze the gas permeability when there are artificial fissures in the soil.%为了研究裂隙膨胀土渗气规律,采用自行设计加工的气体渗透测试装置,对人工制备裂隙膨胀土试样进行渗气试验。结果表明:压实膨胀土中气体渗透符合达西定律;试样完全切开且未夹纸条时,试样中仍然存在贯通裂隙,此时气体渗透系数相比压实膨胀土试样中的渗透系数提高了1倍;土中裂隙的存在为气体运移提供便利通道,改变气体原有运移路径,形成“优势流”现象;对比达西理论和非达西理论分析结果,土体中出现贯通人工裂隙时,采用非达西理论分析更合适。

  14. Martian north polar cap summer water cycle

    CERN Document Server

    Brown, Adrian J; Becerra, Patricio; Byrne, Shane

    2016-01-01

    A key outstanding question in Martian science is 'are the polar caps gaining or losing mass and what are the implications for past, current and future climate?' To address this question, we use observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of the north polar cap during late summer for multiple Martian years, to monitor the summertime water cycle in order to place quantitative limits on the amount of water ice deposited and sublimed in late summer. We establish here for the first time the summer cycle of water ice absorption band signatures on the north polar cap. We show that in a key region in the interior of the north polar cap, the absorption band depths grow until Ls=120, when they begin to shrink, until they are obscured at the end of summer by the north polar hood. This behavior is transferable over the entire north polar cap, where in late summer regions 'flip' from being net sublimating into net condensation mode. This transition or 'mode flip' happens earlier for ...

  15. Microtubule's conformational cap

    DEFF Research Database (Denmark)

    Chretien, D.; Janosi, I.; Taveau, J.C.;

    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...

  16. Root cap influences root colonisation by Pseudomonas fluorescens SBW25 on maize.

    Science.gov (United States)

    Humphris, Sonia N; Bengough, A Glyn; Griffiths, Bryan S; Kilham, Ken; Rodger, Sheena; Stubbs, Vicky; Valentine, Tracy A; Young, Iain M

    2005-09-01

    We investigated the influence of root border cells on the colonisation of seedling Zea mays roots by Pseudomonas fluorescens SBW25 in sandy loam soil packed at two dry bulk densities. Numbers of colony forming units (CFU) were counted on sequential sections of root for intact and decapped inoculated roots grown in loose (1.0 mg m(-3)) and compacted (1.3 mg m(-3)) soil. After two days of root growth, the numbers of P. fluorescens (CFU cm(-1)) were highest on the section of root just below the seed with progressively fewer bacteria near the tip, irrespective of density. The decapped roots had significantly more colonies of P. fluorescens at the tip compared with the intact roots: approximately 100-fold more in the loose and 30-fold more in the compact soil. In addition, confocal images of the root tips grown in agar showed that P. fluorescens could only be detected on the tips of the decapped roots. These results indicated that border cells, and their associated mucilage, prevented complete colonization of the root tip by the biocontrol agent P. fluorescens, possibly by acting as a disposable surface or sheath around the cap.

  17. 路基土密实度测试方法研究综述%Test Method of Subgrade Soil Compactness

    Institute of Scientific and Technical Information of China (English)

    靳建明

    2011-01-01

    It is necessary to control subgrade construction quality in subgrade pavement design to ensure adequate bearing capacity, lower compression and permeability of subgrade.Soil compactness test is an important measure for controlling filling subgrade quality.There are two major test methods at present, naming non-destructive testing and destructive testing.Various test methods are summarized herein and future development direction is also described.%在路基路面设计中,需要控制路基的施工质量,以保证路基具有足够的承载能力、较低的压缩性及渗透性.而土的密实度测试是控制填土路基施工质量的一项重要内容,其测试方法目前主要有两大类:无损测试法和有损测试法.据此,对各种测试方法进行了综述,并阐述了今后的发展方向.

  18. 光滑帽子动态本构模型验证及应用研究%Validation and application of continuous surface cap model used as the dynamic constitutive model of soil

    Institute of Scientific and Technical Information of China (English)

    刘俊新; 杨春和; 刘育田

    2014-01-01

    For simulating the dynamic response of soil under a certain range of impact load caused by projectile penetration,continuous surface cap model was proposed to be used as the dynamic constitutire model of soil.Through model test and numerical simulation,the feasibility and advautages of the model were validated.The influences of different constitutive models and numerical algorithms on penetration depth were analysed.The results show that in the calculation using continuous surface cap model,numerical instability can be overcome in the case of low hydrostatic pressure and low penetrating velocity.Compared with the soil and foam model and the Drucker-Prager model,the continuous surface cap model can more closely reftect the mechanical properties of soil,so,the result will be more resonable.In the simulation of projectile penetration,multi material arbitrary Lagrangian-Eulian (MM-ALE)algorithm was intrduced and it is shown that with MM-ALE algorithm,the mesh distortion and numerical difficulties can be conquered,the calculation accuracy can be thus guaranteed,so that more credible results can be achieved.The results are helpful to study the strength and rigidity of warhead,the stability of explosive during the penetration of projectile and the effect of blast damage after the projectile penetrating into the ground.%通过弹丸侵彻模型试验及数值方法论证光滑帽子模型可较好模拟一定范围内冲击荷载作用下土体动态力学响应。在此基础上分析不同本构模型、数值算法对计算结果影响。分析表明,光滑帽子模型能克服在较的静水压力及低速下数值计算不稳定,与土壤、泡沫模型及 Drucker-Prager 模型相比,基本上能反映土体力学性能,计算结果更合理;用 MM-ALE 算法模拟弹丸侵彻试验能克服网格畸变所致数值计算困难,计算精度能得到保证,计算结果与事实相符。该结果对研究武器触地侵彻过程中弹头强度、刚度、

  19. The leaking soil nitrogen cycle and rising atmospheric N2O: Is there anything we can do to cap the well?

    Science.gov (United States)

    Nutrient management refers to the addition and management of synthetic or organic fertilizers to soils primarily for purposes of increasing the supply of nutrients and efficiency of crop nutrient uptake in order to improve yields while minimizing environmental impact. Nitrogen (N) is generally the m...

  20. Effects of Corn Straw Mulching No-tillage on Soil Compaction and Soil Moisture%玉米秸秆覆盖免耕对土壤紧实度及水分的影响

    Institute of Scientific and Technical Information of China (English)

    杜会石; 滕泽宇; 陈智文; 李天祺

    2015-01-01

    To study the effects of corn straw mulch and no-till measurement on the soil properties to the physical proper-ties,such as its compaction and moisture .Series of experiments on test field were conducted at Lishu county , Jilin prov-ince .The changing characteristics of compaction and moisture in different topsoil depth under the different conditions of no-till in different corn straw mulch coverage and no-till in years varied were discussed .The results showed that soil compaction of corn straw mulch and no-till at depth of 0~20 cm is higher than that of conventional tillage ( CK ) , but lower at depth of 20~50cm,and with the increase of no-till time, the tillage pan fade away.Soil moisture of corn on-till at depth of 0~50 cm enhanced by 14.78%~23.64%compared with CK.And it shows the same change trend with cov-erage and persists years of corn straw mulch and no-till.But with the soil depth increased ,it enhances first and drop af-ter .Hence , at rain-fed farming areas , it is quite significant and vital to take advantage of straw mulch and no-till tech-nology to promote crop growth and ensure its high and stable yield .%为研究秸秆覆盖免耕措施对土壤紧实度、水分等物理性质的影响,以吉林省梨树县高家村试验田为研究对象,探讨免耕秸秆不同覆盖量和免耕秸秆不同覆盖年限条件下,不同耕层深度土壤紧实度及水分变化特征。结果表明:秸秆覆盖免耕地0~20cm耕层土壤紧实度高于传统耕作(CK),20~50cm 耕层土壤紧实度低于 CK,因免耕年限的增加,犁底层逐渐消失。秸秆覆盖免耕地0~50 cm 土壤含水量较 CK 提高了14.78%~23.64%,且随秸秆覆盖量、秸秆还田年限的增加而增大;随耕层深度的增加,水分含量先增加后减少。因此,在雨养农业区,因地制宜地采取秸秆覆盖免耕措施对促进作物生长、保证粮食高产稳产具有重要意义。

  1. Martian north polar cap summer water cycle

    Science.gov (United States)

    Brown, Adrian J.; Calvin, Wendy M.; Becerra, Patricio; Byrne, Shane

    2016-10-01

    A key outstanding question in Martian science is "are the polar caps gaining or losing mass and what are the implications for past, current and future climate?" To address this question, we use observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of the north polar cap during late summer for multiple Martian years, to monitor the summertime water cycle in order to place quantitative limits on the amount of water ice deposited and sublimed in late summer. We establish here for the first time the summer cycle of water ice absorption band signatures on the north polar cap. We show that in a key region in the interior of the north polar cap, the absorption band depths grow until Ls = 120, when they begin to shrink, until they are obscured at the end of summer by the north polar hood. This behavior is transferable over the entire north polar cap, where in late summer regions 'flip' from being net sublimating into net condensation mode. This transition or 'mode flip' happens earlier for regions closer to the pole, and later for regions close to the periphery of the cap. The observations and calculations presented herein estimate that on average a water ice layer ∼70 microns thick is deposited during the Ls = 135-164 period. This is far larger than the results of deposition on the south pole during summer, where an average layer 0.6-6 microns deep has been estimated by Brown et al. (2014) Earth Planet. Sci. Lett., 406, 102-109.

  2. Estado nutricional do coqueiro cultivado em solos submetidos a diferentes níveis de compactação e umidade Nutritional status of coconut grown in soils submitted to different compaction and moisture levels

    Directory of Open Access Journals (Sweden)

    Romano R. Valicheski

    2011-11-01

    Full Text Available Com o objetivo de avaliar o efeito da compactação e da umidade do solo na absorção de nutrientes pelo coqueiro anão-verde, implantou-se um experimento em casa de vegetação em Campos dos Goytacazes, RJ. O delineamento experimental utilizado foi em blocos casualizados com tratamentos distribuídos em esquema fatorial (2 x 4 x 4, com três repetições, sendo duas classes de solo (Argissolo Amarelo Distrocoeso latossólico e Cambissolo Háplico Tb Distrófico típico gleico, quatro níveis de compactação em subsuperfície e quatro condições hídricas. Os solos atuaram de forma diferenciada no suprimento de nutrientes, sendo determinado o teor foliar de Mg e Cu mais elevado nas plantas cultivadas no Cambissolo e os de K e Ca nas cultivadas no Argissolo. O incremento da umidade do solo alterou a disponibilidade de nitrogênio no Argissolo fazendo com que as plantas cultivadas nos maiores níveis de umidade apresentassem teor foliar mais elevado de N. Também no Argissolo a compactação afetou a absorção de manganês e cloro observando-se, nas plantas cultivadas nos níveis mais elevados de compactação, teor foliar maior de Mn e menor de Cl.In order to evaluate the effect of compaction and moisture in absorption of by greennutrients dwarf coconut plants, an experiment was carried out under greenhouse, in Campos dos Goytacazes, RJ. The experimental design was in randomized block in factorial scheme (2 x 4 x 4, with three repetitions. The treatments were 2 soil classes (Typic Kandiudult and Umbric Dystrochrept, 4 levels of soil compaction and 4 water levels. The soils were differentiated in the nutrient supply, with higher levels of Mg and Cu in plants cultivated in Umbric Dystrochrept and K and Ca in Typic Kandiudult soil. The elevation of soil moisture altered the availability of nitrogen, so plants cultivated in Typic Kandiudult soil presented higher levels of N in leaves under in the highest soil moisture level. In Typic Kandiudult

  3. 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)

  4. Compact Lumps

    CERN Document Server

    Bazeia, D; Menezes, R

    2015-01-01

    We study the presence of lumplike solutions in models described by a single real scalar field with standard kinematics in two-dimensional spacetime. The results show several distinct models that support the presence of bell-shaped, lumplike structures which may live in a compact space.

  5. 饱和钙质砂爆炸密实动力特性试验研究%Experimental study of dynamic characteristics of saturated calcareous soil explosion compaction

    Institute of Scientific and Technical Information of China (English)

    徐学勇; 汪稔; 胡明鉴; 孟庆山

    2012-01-01

    开展饱和钙质砂爆炸密实动力特性试验研究,探索饱和钙质砂爆炸密实机制和密实效果,对钙质砂地层中进行的工程建设有重要的理论意义和工程实用价值.通过控制爆炸参数,测试不同参数作用时钙质砂爆炸前后声波特性和表面沉降规律,揭示饱和钙质砂爆炸密实动力特性.试验结果表明:钙质砂高孔隙比和颗粒破碎特性对爆炸密实效果有重要影响.爆炸密实作用后,在爆炸近区,钙质砂颗粒受到较强爆炸冲击作用,导致钙质砂颗粒破碎而形成破碎区和压缩区,压缩区随着时间的推移有松弛的趋势,钙质砂颗粒结构重新固结过程在爆炸后2h内基本完成.%Exploring saturated calcareous soil explosion compacting mechanism and effect through the experimental study have great theoretical and practical significance on engineering construction in calcareous soil area. First, longitudinal wave velocity and surface settlement are tested at different moments before and after explosion under different explosive parameters through indoor mini-explosive compacting experiment. And then, wave velocity characteristics and settlement rules are studied to reveal dynamic characteristics of saturated calcareous soil explosion compaction through analyzing and contrasting the test results. It is suggested that high void ratio and particle breakage characteristics of calcareous soil have great impact on compacting effect. After explosion, breakage and compression cavity are formed in the neighborhood of explosion because of calcareous soil particle breakage resulted from the heavy shock of explosion, compression cavity would relax along with time lapse, the explosion compaction process is completed within two hours.

  6. Propriedades físico-hídricas do solo e demanda energética de haste escarificadora em Argissolo compactado Soil physicohydric properties and chisel energy demand in a compacted Alfisol

    Directory of Open Access Journals (Sweden)

    Marcelo Ivan Mentges

    2010-03-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da compactação nos atributos físico-hídricos do solo e na demanda energética da haste escarificadora, além de avaliar as propriedades físico-hídricas abaixo da profundidade de trabalho da haste. O trabalho foi conduzido em Argissolo Vermelho-Amarelo de textura francoarenosa, com os seguintes tratamentos: plantio direto por 13 anos; plantio direto por 13 anos em solo escarificado; plantio direto em solo com compactação adicional; e plantio direto em solo com compactação adicional escarificado. A compactação, ao longo da profundidade escarificada, foi verificada por meio dos dados de esforço de tração associados à haste escarificadora, obtidos com auxílio de um anel octogonal ligado a um módulo de aquisição de dados. Foram determinados densidade, porosidade total, macroporosidade, microporosidade, condutividade hidráulica saturada e resistência mecânica do solo à penetração. A compactação elevou a densidade e a resistência mecânica à penetração do solo, reduziu a porosidade total e a macroporosidade, porém sem causar efeitos significativos na microporosidade. A compactação aumentou a demanda energética da haste escarificadora em 21,64%, o que elevou os valores médios de esforço de tração de 5,33 para 6,35 kN. A escarificação não elevou o estado de compactação do solo abaixo da profundidade de trabalho da haste escarificadora, em solo francoarenoso.The objective of this work was to evaluate the soil compaction effect on its physicohydric properties and on chisel energy demand, as well as to quantify the behavior of these properties below the chisel working depth. The experiment was carried out in a sandy loam Alfisol, with the following treatments: no-tillage for 13 years; no-tillage for 13 years and chiseling; no-tillage with additional compaction; and no-tillage with additional compaction and chiseling. Compaction along the chiseling depth was verified

  7. Compactação de misturas solo-grits para emprego em estradas florestais: influência do tempo decorrido entre mistura e compactação na resistência mecânica Compaction of soil-grits mixtures for use in forestry road: influence of time between mixture and compaction on mechanical strength

    Directory of Open Access Journals (Sweden)

    Reginaldo Sérgio Pereira

    2006-06-01

    Full Text Available Vários fatores influenciam a execução e a "performance" de camadas de pavimentos rodoviários constituídas de solos estabilizados quimicamente, com destaque para a homogeneização da mistura e o período de tempo decorrido entre a mistura e a compactação, bem como para a escolha do equipamento de compactação. Aborda-se, no presente artigo, a influência do tempo decorrido entre a mistura e a compactação (TMC nos parâmetros de compactação e na resistência mecânica de misturas de dois solos típicos da Zona da Mata Norte de Minas Gerais, com o resíduo da indústria de celulose denominado "grits", com vistas à sua aplicação em estradas florestais. Analisa-se, também, a influência de diferentes lotes desse resíduo na resistência mecânica das misturas. Trabalhou-se com os resultados de ensaios de índice de suporte Califórnia (ISC ou CBR realizados em corpos-de-prova de misturas moldados na energia de compactação do ensaio Proctor Intermediário. Os resultados permitem concluir que o tempo decorrido entre mistura e compactação influencia significativamente a resistência mecânica das misturas analisadas, recomendando-se, para fins práticos, que estudos dessa natureza devam ser feitos em bases regionais de ocorrência de solos. Observou-se, também, influência significativa do lote na resistência mecânica das misturas.Many factors affect the construction and performance of chemically stabilized highway pavement soil layers, especially mixture homogenization, time between mixture and compaction, and selection of compaction equipment. Regarding forest road application, this paper addresses the influence of time between mixture and compaction (TMC on compaction optimum parameters and on mechanical strength of mixtures of two typical soils from the region `Zona da Mata Norte', State of Minas Gerais, and grits, a waste from the cellulose industry, as well as the influence of grits sampling on the mechanical strength of

  8. A Phrygian Cap

    Directory of Open Access Journals (Sweden)

    Marie-Janne S. van Kamp

    2013-08-01

    Full Text Available A Phrygian cap is a congenital anomaly of the gallbladder with an incidence of 4%. It can simulate a mass in the liver during hepatobiliary imaging and is sometimes mistaken for pathology. A Phrygian cap, however, has no pathological significance and normally causes no symptoms. A case will be presented where a Phrygian cap was found by coincidence during surgery. The patient was operated for colon cancer with liver metastasis in segment V. He underwent a simultaneous right hemicolectomy and wedge resection of the liver lesion. During perioperative inspection, a gallbladder with a folded fundus was seen. This deformity was, in retrospective, detected on the preoperative MRI scan. The patient underwent cholecystectomy to make the wedge resection easier to perform. Otherwise, cholecystectomy for a Phrygian cap is only indicated in case of symptoms. Radiographic imaging can be helpful in narrowing the differential diagnosis. To our knowledge, there is no recent literature about the Phrygian cap and its imaging aspects. Nowadays, multiphase MRI, or multiphase CT in case of MRI contraindication, are the first choices of hepatobiliary imaging.

  9. Sistema radicular da soja em função da compactação do solo no sistema de plantio direto Soybean root system in function of soil compaction under no-tillage system

    Directory of Open Access Journals (Sweden)

    Eduardo Garcia Cardoso

    2006-03-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos da compactação do solo sobre suas propriedades morfoestruturais e sobre o desenvolvimento radicular da soja, sob sistema plantio direto, em um experimento conduzido num Latossolo Vermelho distroférrico, em Londrina, PR. O delineamento utilizado foi o de blocos ao acaso, com parcelas subdivididas e quatro repetições. Foram constituídos dois tratamentos de manejo nas parcelas: um em solo escarificado à profundidade de 20-25 cm, com densidade do solo de 1,17 Mg m-3; e outro em solo compactado, a 12 cm de profundidade, e densidade de 1,38 Mg m-3. Nas subparcelas, foram semeadas duas cultivares de soja, Embrapa-4 e BR-16. A presença de camadas mais compactas no perfil do solo provocou o desenvolvimento radicular em zonas de menor resistência, em poros biológicos e nas fissuras do solo. A produção de grãos não apresentou diferença entre os tratamentos, graças à adequada disponibilidade hídrica durante o período avaliado. A cultivar Embrapa-4 apresentou maior crescimento radicular em estruturas compactas, comparada à cultivar BR-16.An experiment was carried out on a Rhodic Ferralsol, in Londrina, PR, to evaluate the soil compaction effects on soil morphostructure and on soybean root distribution, under no-tillage system. The field experiment was arranged in a completely randomized block (split plot design with four replicates, and with the compacted treatments in the main plots and soybean varieties in subplots. The treatments were: one scarified soil until 20-25 cm depth layer with bulk density of 1.17 Mg m-3, and one compacted soil with bulk density of 1.38 Mg m-3, in a 12 cm depth. Two varieties of soybean, Embrapa-4 and BR-16, were cultivated on subplots. Roots developed in zones with less resistance of penetration and in biological tunnels. The soybean grain yield was not different under compacted and noncompacted soil, because soil water moisture was adequate. Embrapa-4 showed

  10. 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....

  11. Subsoil Compaction as a Climate Damage Indicator

    Directory of Open Access Journals (Sweden)

    Márta Birkás

    2009-06-01

    Soil compaction has become a soil management problem during the last decade as a result of the occurrence of periods of water-logging as well as droughts. This study contains an evaluation of factors relating to subsoil compaction, as indicator of climate effects on arable fields. This paper is based on soil condition monitoring and measuring that was started 32 years ago and on short and long-term experiments modeling and checking the extension of compaction in the soil. The survey comprised 1526 monitoring places and 38 experimental plots. The following five points were chosen for monitoring: 1 root zone state (to a depth of 0-60 cm; 2 occurrence of compacted layer (indicating likelihood of risk; 3 extension of the compacted layer (indicating the degree of damage; 4 long term effects of tillage (soil state deterioration or improvement, and 5 tillage-induced water-logging and drought damage impacts on yield loss. The main objectives of the experiments were: 1 occurrence and the extent of tillage-pan damage in soils of different susceptibility to compaction; 2 consequences on water management in each of the years covered by the experiments; 3 soil quality consequences, and 4 alleviation of pan-compaction by mechanical and biological methods. Long-term field monitoring and experimental work have both convincingly proven a correlation between subsoil compaction and the degree of climatic damage. In view of the findings, trends in soil tillage can be grouped into the following two categories: climate damage mitigating and climate-stress increasing ones. The formation and location of compacted layers provided information concerning the depth, the method and the type of tillage applied, along with the expected risk for crop production under extreme climate conditions.

  12. Compact NMR

    Energy Technology Data Exchange (ETDEWEB)

    Bluemich, Bernhard; Haber-Pohlmeier, Sabina; Zia, Wasif [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMC)

    2014-06-01

    Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

  13. Compact NMR

    International Nuclear Information System (INIS)

    Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

  14. 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

  15. Influence Analysis of Poisson Ration of Soil on Compacting Displacement Field of Single Press-in Pipe Pile%土体泊松比对压入管桩单桩挤土位移场的影响

    Institute of Scientific and Technical Information of China (English)

    储召军; 石少卿; 陈怀庆; 张有来

    2013-01-01

    On the basis of the finite element software ABAQUS,an appropriate finite element model which adopts contact algo⁃rithm to simulate the interaction between pile and soil and utilizes the modified Cambridge model as the constitutive model of soil is given according to the actual piling process of press⁃in pipe pile through vertical displacement loading on pile top and suitable mesh technology. The pile⁃sinking process is simulated and the compacting displacement field is studied through this new finite element model. The comparative analysis of compacting displacement field of single press⁃in pipe pile is carried out under different Poisson rations of soil. The result shows that the distribution rule of vertical and horizontal displacement with the radial distances or with the depths at different Poisson rations tends to be same. The variation of Poisson ration of soil could greatly affect the vertical and horizon⁃tal compacting displacement field caused by the pile⁃sinking of press⁃in pipe pile. The bigger Poisson ration of soil is,the bigger verti⁃cal and horizontal compacting displacements are.%  基于ABAQUS有限元软件,采用主从接触算法模拟桩-土相互作用、修正剑桥模型作为土体本构模型,通过在桩顶施加竖向位移荷载以及合适的网格划分技术建立了较为符合压入管桩压桩实际的有限元模型。利用得到的有限元模型模拟了压入管桩压桩产生的挤土位移场,对不同泊松比时压入管桩单桩挤土位移场进行了对比分析。结果表明:不同泊松比时竖向和水平挤土位移场沿深度方向和径向的分布规律趋于一致;土体泊松比的变化会对压入管桩压桩产生的竖向和水平挤土位移场产生较大影响;泊松比越大,压桩产生的竖向和水平挤土位移越大。

  16. Effect of Subsoil Compaction on Hydraulic Parameters

    DEFF Research Database (Denmark)

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

    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...... that for the upper soil depth, a significant increase in bulk density was measured for the compacted treatment. For the lower depth differences were less pronounced. For the saturated hydraulic conductivity, the results indicated a decrease of the hydraulic conductivity for the compacted treatment for the upper...

  17. 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 in

  18. Compactação de um solo de uso florestal submetido ao tráfego de arraste de madeira Evaluation of compaction of a forest soil subjected to skidder traffic

    Directory of Open Access Journals (Sweden)

    Sebastião Eudes Lopes

    2006-06-01

    Full Text Available Este trabalho teve como principal objetivo a avaliação dos níveis de compactação de um Latossolo Vermelho-Amarelo, de uso florestal, submetido ao tráfego comparativo entre duas versões de máquina de arraste de madeira, sobre pneus e esteiras, tendo em vista a escassez de informações sobre o tema e, ainda, considerando que o tráfego de máquinas habitualmente resulta em impactos no ecossistema, influenciando a qualidade dos recursos hídricos, a compactação do solo e a produtividade da floresta. As propriedades físicas do solo avaliadas foram: densidade, porosidade total e resistência mecânica do solo à penetração. O delineamento experimental empregado foi um esquema fatorial 2 x 3 x 3, ou seja, duas versões de máquina empregadas em três condições de operação, discutidas em relação à testemunha sem tráfego e em três profundidades, tendo quatro repetições. Foi também aplicado o teste de interações para avaliar o efeito das duas versões do trator arrastador em relação ao número de percursos das máquinas. As médias foram comparadas pelo teste de Dunnet a 5% de significância. A análise dos resultados obtidos apontou que, na faixa de profundidade entre 0 e 15 cm, o trator arrastador sobre pneus, trafegando com carregamento de madeira em um ou dois percursos, provocou efeitos na compactação do solo. Nas mesmas condições, o tráfego do trator arrastador sobre esteiras, em dois percursos, produziu efeito análogo. Nas profundidades entre 15 e 50 cm, somente dois percursos sobre pneus produziram alteração na compactação do solo.The objective of this research was to evaluate compaction of a Red-Yellow Latosol subjected to forestry traffic including two types of skidder: a wheeled-clambunk skidder and a tracked one. This study tries to remedy the lack of information on this subject, considering that mechanized traffic can result in several impacts on the environment. These impacts are related to soil

  19. Numerical evaluation of the capping tendency of microcrystalline cellulose tablets during a diametrical compression test.

    Science.gov (United States)

    Furukawa, Ryoichi; Chen, Yuan; Horiguchi, Akio; Takagaki, Keisuke; Nishi, Junichi; Konishi, Akira; Shirakawa, Yoshiyuki; Sugimoto, Masaaki; Narisawa, Shinji

    2015-09-30

    Capping is one of the major problems that occur during the tabletting process in the pharmaceutical industry. This study provided an effective method for evaluating the capping tendency during diametrical compression test using the finite element method (FEM). In experiments, tablets of microcrystalline cellulose (MCC) were compacted with a single tabletting machine, and the capping tendency was determined by visual inspection of the tablet after a diametrical compression test. By comparing the effects of double-radius and single-radius concave punch shapes on the capping tendency, it was observed that the capping tendency of double-radius tablets occurred at a lower compaction force compared with single-radius tablets. Using FEM, we investigated the variation in plastic strain within tablets during the diametrical compression test and visualised it using the output variable actively yielding (AC YIELD) of ABAQUS. For both single-radius and double-radius tablets, a capping tendency is indicated if the variation in plastic strain was initiated from the centre of tablets, while capping does not occur if the variation began from the periphery of tablets. The compaction force estimated by the FEM analysis at which the capping tendency was observed was in reasonable agreement with the experimental results. PMID:26188313

  20. Subsoil Compaction as a Climate Damage Indicator

    Directory of Open Access Journals (Sweden)

    Márta Birkás

    2009-06-01

    Full Text Available Some forms of soil compaction occur on arable lands both in Hungary (1.82 million ha and in Croatia (0.97 million ha having negative impacts on agricultural production. Tillage-induced subsoil compaction has oft en occurred in the Pannonian region in relation to traffic-induced compaction.Soil compaction has become a soil management problem during the last decade as a result of the occurrence of periods of water-logging as well as droughts. This study contains an evaluation of factors relating to subsoil compaction, as indicator of climate effects on arable fields. This paper is based on soil condition monitoring and measuring that was started 32 years ago and on short and long-term experiments modeling and checking the extension of compaction in the soil. The survey comprised 1526 monitoring places and 38 experimental plots. The following five points were chosen for monitoring: 1 root zone state (to a depth of 0-60 cm; 2 occurrence of compacted layer (indicating likelihood of risk; 3 extension of the compacted layer (indicating the degree of damage; 4 long term effects of tillage (soil state deterioration or improvement, and 5 tillage-induced water-logging and drought damage impacts on yield loss. The main objectives of the experiments were: 1 occurrence and the extent of tillage-pan damage in soils of different susceptibility to compaction; 2 consequences on water management in each of the years covered by the experiments; 3 soil quality consequences, and 4 alleviation of pan-compaction by mechanical and biological methods. Long-term field monitoring and experimental work have both convincingly proven a correlation between subsoil compaction and the degree of climatic damage. In view of the findings, trends in soil tillage can be grouped into the following two categories: climate damage mitigating and climate-stress increasing ones. The formation and location of compacted layers provided information concerning the depth, the method and the

  1. The Applicability of Soil Density Gauge in Subgrade Compaction Test%SDG土壤密度仪在路基压实度检测中的适用性研究

    Institute of Scientific and Technical Information of China (English)

    杜智亮; 顾欢达; 薛国强; 胡舜

    2011-01-01

    SDG无核土壤密度仪是一种无损快速填土压实度检测装置,可用于压实填土密实度的快速无损检测。在了解SDG无核土壤密度仪的工作原理和确定测试所需的前置参数设定的基础上,通过现场传统灌砂法和SDG测试法的对比试验及室内模拟试验,对SDG密度仪在压实填土密实度快速检测的适用性和可靠性进行了研究,重点考察了填土含水条件和密实程度对测试结果的影响,为SDG密度仪在工程上的应用作出了有益探讨。%SDG,a non-nuclear soil density gauge,is a nondestructive and high-speed device to test the compaction of the soil-filling density.Based on the understanding of the SDG working principles and needed pre-set parameters,the paper defined the applicability and reliability of SDG rapid testing the compacted soil density by comparing between the conventional sand-filling method and SDG and the indoor simulation tests.The paper focused on the influence of water conditions and compaction situations on the test result,which established a foundation for SDG application in the engineering project.

  2. Experimental study on back filling and rolling compaction of coarse-grained salty soil%粗颗粒盐渍土回填碾压试验研究

    Institute of Scientific and Technical Information of China (English)

    刘志伟; 程东幸; 张希宏

    2012-01-01

    在新疆大规模的开发建设中,大量的工程场地将遇到粗颗粒盐渍土。因厂址区附近建筑材料缺乏,外运距离远,场地回填及地基换填料同时成为工程面临的难题。本文遵循就地取材的原则,开展了粗颗粒盐渍土现场回填碾压试验和专题研究,确定了粗颗粒盐渍土作为回填料的适宜性及相关设计施工参数。试验研究表明:当粗颗粒盐渍土易溶盐含量不是很高,具轻微溶陷性,并不考虑盐胀时,场地料重新回填可消除原有的溶陷性,且地基承载力可达170kPa,通过级配改良,混合料回填碾压后地基承载力可达300kPa,有了较大提高。其成果的获得,具有明显的工程效益。%In the large-scale development and construction in Xinjiang Uygur Autonomous Region, the most engineering site will encounter the coarse-grained salty soil. Due to the lack of building materials near the site and the long-distance transport, the materials for the back filling and soil replacement are facing the engineering problems. Following the principle to obtain raw material locally, the backfill compaction tests with coarse-grained salty soil and the special study in the field are carried out, and the suitability of the coarse-grained salty soil as backfill material and the relative design and construction parameters are determined. When the easy resolving salt content in coarse-grained salty soil is not very high, and with slight thaw collapsibility, without considering the expansion of salts, the experimental study shows that the thaw collapsibility has been eliminated after the back filling and rolling compaction with the site soil, and the bearing capacity can reach 170kPa. Through improving the gradation, the strength of the compacted backfill has been greatly improved; the bearing capacity of the mixed material can reach 300kPa, which obtain the favorable engineering benefit.

  3. Compact Radiometers Expand Climate Knowledge

    Science.gov (United States)

    2010-01-01

    To gain a better understanding of Earth's water, energy, and carbon cycles, NASA plans to embark on the Soil Moisture Active and Passive mission in 2015. To prepare, Goddard Space Flight Center provided Small Business Innovation Research (SBIR) funding to ProSensing Inc., of Amherst, Massachusetts, to develop a compact ultrastable radiometer for sea surface salinity and soil moisture mapping. ProSensing incorporated small, low-cost, high-performance elements into just a few circuit boards and now offers two lightweight radiometers commercially. Government research agencies, university research groups, and large corporations around the world are using the devices for mapping soil moisture, ocean salinity, and wind speed.

  4. 饱和土中挤土桩竖向振动简化计算模型%Simplified Calculation Model for Vertical Vibration of Compaction Pile in Saturated Soil

    Institute of Scientific and Technical Information of China (English)

    李强; 王奎华; 张智卿

    2011-01-01

    A simplified calculation model for vertical vibration of compation pile considering the inhomogeneous compaction zone of soil in the vicinity of the pile disturbed by pile driving was established. An analytical solution was deduced in frequency domain by means of variable separating method and then a semi-analytical solution in time domain was obtained using numerical convolution method. Numerical calculation results from the frequency domain and time domain indicate that the equivalent radius of compaction zone has major effect on pile dynamic response, as well as the ratio of exceeding pore pressure. It can also be concluded that the actual interaction of pile and soil will be weaken due to the compaction zone caused by pile driving, a fact can be deduced that the interaction of pile and soil is overestimated under the ideal undisturbed model. The presented model can reflect the interaction of pile and soil better than the perfect contact model. Small strain reflected wave test of compaction pile can be conducted as soon as possible in order to obtain greater depth of pile test in practical engineering.%根据挤土分区模型,建立了饱和土中考虑孔压消散的桩侧非均质挤土区桩竖向振动简化计算模型;通过分离变量方法,得到了桩竖向振动频域解析解和时域半解析解,分析了挤土区对桩竖向振动特性的影响.数值计算结果表明:挤土区当量半径和桩周孔压增量比越小,桩周土对桩的约束作用越强;挤土区的存在使桩土间的相互作用减弱,采用均质土完全粘结模型过高地估计了土对桩的约束能力,实际工程中尽早开展挤土桩小应变反射波检测有利于获得较大的测试深度.

  5. 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

  6. Performance of blasting caps

    Science.gov (United States)

    Bement, Laurence J. (Inventor); Schimmel, Morry L. (Inventor); Perry, Ronnie B. (Inventor)

    1993-01-01

    Common blasting caps are made from an aluminum shell in the form of a tube which is closed at both ends. One end, which is called the output end, terminates in a principal side or face, and contains a detonating agent which communicates with a means for igniting the detonating agent. The improvement of the present invention is a flat, steel foil bonded to the face in a position which is aligned perpendicularly to the longitudinal axis of the tube.

  7. Subsoil compaction assessed by visual evaluation and laboratory methods

    DEFF Research Database (Denmark)

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

    2016-01-01

    Subsoil compaction is one of the majorcauses of land degradationworldwide and therefore a major threat to future crop productivity. The objective of this contribution was to evaluate the effects of compaction treatments on soil structure based on the numerical visual evaluation of subsoil structure...... (SubVESS) method and on quantitative measurements of soil pore characteristics. The effect of soil compaction was evaluated using treatments from a compaction experiment initiated in 2010 at Research Centre Flakkebjerg, Denmark, on a sandy loam soil using five levels of compaction. In this study we......) on the soil cores. We estimated the blocked air-filled porosity and pore continuity index from the relationship between air permeability and air-filled porosity for 30 to 300 hPa matric potentials. Assessment using the SubVESS method showed a marked effect of the M8 treatment on soil structural quality down...

  8. Assessment of the soil compaction of two ultisols caused by logging operations Avaliação da compactação do solo de dois argissolos causada pelas operações de colheita florestal

    Directory of Open Access Journals (Sweden)

    Moacir de Souza Dias Junior

    2008-12-01

    Full Text Available The impact of wood loads on bulk density and preconsolidation pressure and of harvester and forwarder traffic on rut depth, bulk density and preconsolidation pressure of two Ultisols were examined in this study. Our objective was to quantify the threshold beyond which significant soil compaction and rutting would occur. This study was carried out in the county of Eunápolis, state of Bahia, Brazil, (16 º 23 ' 17 '' S and 39 º 10 ' 06 '' W; altitude 80 m asl in two Ultisols (PAd2 and PAd3 with different texture classes, in experimental areas with eucalypt plantation. The study involved measurements at the wood load site and machine driving at specific locations in the forest during logging operations. The treatments consisted of one harvester pass and, 8, 16 and 40 passes of a fully loaded forwarder. Thresholds were established based on the rut depth and percentage of preconsolidation pressure values in the region of additional soil compaction defined in the bearing capacity model. The percentage of soil samples with values of preconsolidation pressure in the region of additional soil compaction indicated a greater susceptibility of PAd3 than of PAd2 to soil compaction. The threshold levels established here based on preconsolidation pressure and rut depth indicated that no more than eight forwarder passes should be allowed in loading operations in order to minimize soil compaction.O impacto do empilhamento da madeira na densidade do solo (Ds e na pressão de preconsolidação (σp e o do tráfego de um Harvester e de um Forwarder na profundidade dos sulcos e na Ds e σp, em dois Argissolos, foram avaliados neste estudo, cujo objetivo foi quantificar o limite acima do qual a compactação e a profundidade dos sulcos poderiam ocorrer sem causar degradação estrutural. O estudo foi realizado na cidade de Eunápolis, Bahia (16 º 23 ' 17 '' S, 39 º 10 ' 06 '' W; e 80 m de altitude, em dois Argissolos Amarelos distróficos (PAd2 e PAd3 cultivados

  9. Efeito do composto orgânico e compactação do solo no milho e nutrientes do solo Effect of compaction and organic compost application on corn biomass and macronutrient contents in soil

    Directory of Open Access Journals (Sweden)

    Pedro N. F. Rodrigues

    2011-08-01

    Full Text Available Quando bem aproveitados, os resíduos orgânicos conduzem a grandes benefícios disponibilizando matéria orgânica e nutriente ao solo. Neste contexto, objetivou-se, no presente estudo, verificar o efeito da aplicação de doses de composto orgânico em dois solos submetidos a diferentes compactações na biomassa seca do milho. Para isto se aplicaram, em 54 vasos, três doses de composto orgânico nas quantidades 0 (testemunha, 40 e 80 g dm-3, em um Argissolo Vermelho Escuro e em um outro Argissolo Vermelho-Amarelo, coletados no horizonte Ap, no perfil de 0 a 0,20 m, conduzidos em três diferentes densidades (1,3; 1,5 e 1,7 kg dm-3 e três repetições. A cultura utilizada no experimento foi o milho (Zea mays, cultivar Itapuã 700. As variáveis avaliadas foram biomassa seca da parte aérea do milho (MS e os teores de N, P, K, Ca, Mg e carbono orgânico total (COT do solo. Os resultados obtidos indicaram que a aplicação do composto orgânico causou efeito significativo sobre os teores dos macronutrientes disponíveis e COT e a compactação do solo pouco afetou as variáveis estudadas.When well utilized, organic residues lead to great benefits making organic matter and nutrients available in soils. In this context, the present study had the objective to evaluate the effect of organic compost doses on two soils submitted to different compactions and on corn biomass. Thus, in 54 pots were added three doses 0, 40 or 80 g dm-3 of organic compost in a Dark Red Argisoil or Red Yellowish Argisoil, collected from the Ap horizon (depth of 0 to 0.20 m, submitted to three compaction degrees (1.3, 1.5 and 1.7 kg dm-3, with three replications. The crop used in the experiment was corn (Zea mays, cultivar Itapuã 700. The plant growth, and content of N, P, K, Ca, Mg and organic carbon (TOC in soil were evaluated. The results point out that the organic compost application significantly affected soil OC and macronutrients, but little effect was induced by

  10. 钻孔挤密桩处理强湿陷性黄土地基试验研究%Field tests on pre-bored compaction lime-soil pile (down-hole dynamic compaction method) to improve serious collapsible loess

    Institute of Scientific and Technical Information of China (English)

    刘志伟; 申汝涛

    2009-01-01

    挤密桩法用于处理湿陷性黄土地基,可有效地消除土的湿陷性和提高地基承载力.某拟建电厂工程针对强湿陷性黄土地基,采用钻孔挤密桩(DDC工法)复合地基的处理方法开展现场试验研究.通过采用载荷试验、标准贯入试验等原位测试方法,对桩间土、桩体及复合地基的承载性能、变形参数进行了评价和分析,重点进行了自然工况和浸水工况下的对比研究,对地基处理效果进行了综合评价.%The compaction method used to control the subsoil of collapsible loess can eliminate collapsibility and improve bearing capacity of loess effectively. For serious collapsible loess in a power plant to be constructed, pre-bored compaction lime-soil piles (down-hole dynamic compaction method) field test studies were carried out. After the construction of the test piles were finished, a lot of in-situ tests including plate loading test, standard penetration test, etc., were used to evaluate the bearing capacity of the soil between piles, the piles and the composite foundation, and to test the deformation parameters. Especially, comparative research between natural status and soaked status of composite foundation as well as comprehensive evaluation of effects of ground treatment were carried out.

  11. Capping the Mortgage Interest Deduction

    OpenAIRE

    Anderson, John E.; Clemens, Jeffrey; Hanson, Andrew

    2007-01-01

    In this paper we examine the economic implications of several policy options for capping the mortgage interest deduction (MID). We extend the standard user–cost model of owner–occupied housing to include a cap on the mortgage size receiving tax–favored status. Our user–cost estimates for taxpayers with mortgages above the current–law cap are 4.41 percent higher than estimates from a model without the cap. We simulate the share of mortgage dollars that would be subject to three alternative cap...

  12. Rules of thumb for minimising subsoil compaction

    DEFF Research Database (Denmark)

    Schjønning, Per; Lamandé, Mathieu; Keller, T;

    2012-01-01

    Subsoil compaction is persistent and can affect important soil functions including soil productivity. The aim of this study was to develop recommendations on how to avoid subsoil compaction for soils exposed to traffic by machinery at field capacity. We measured the vertical stress in the tyre......–soil contact area for two traction tyres at ca. 30- and 60-kN wheel loads on a loamy sand at field capacity. Data on resulting stress distributions were combined with those from the literature for five implement tyres tested at a range of inflation pressures and wheel loads. The vertical stress in the soil...... was primarily determined by wheel load, but an effect of the other factors was also detected. Based on published recommendations for allowable stresses in the soil profile, we propose the ‘50-50 rule’: At water contents around field capacity, traffic on agricultural soil should not exert vertical stresses...

  13. Saltstone Clean Cap Formulation

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C

    2005-04-22

    The current operation strategy for using Saltstone Vault 4 to receive 0.2 Ci/gallon salt solution waste involves pouring a clean grout layer over the radioactive grout prior to initiating pour into another cell. This will minimize the radiating surface area and reduce the dose rate at the vault and surrounding area. The Clean Cap will be used to shield about four feet of Saltstone poured into a Z-Area vault cell prior to moving to another cell. The minimum thickness of the Clean Cap layer will be determined by the cesium concentration and resulting dose levels and it is expected to be about one foot thick based on current calculations for 0.1 Ci Saltstone that is produced in the Saltstone process by stabilization of 0.2 Ci salt solution. This report documents experiments performed to identify a formulation for the Clean Cap. Thermal transient calculations, adiabatic temperature rise measurements, pour height, time between pour calculations and shielding calculations were beyond the scope and time limitations of this study. However, data required for shielding calculations (composition and specific gravity) are provided for shielding calculations. The approach used to design a Clean Cap formulation was to produce a slurry from the reference premix (10/45/45 weight percent cement/slag/fly ash) and domestic water that resembled as closely as possible the properties of the Saltstone slurry. In addition, options were investigated that may offer advantages such as less bleed water and less heat generation. The options with less bleed water required addition of dispersants. The options with lower heat contained more fly ash and less slag. A mix containing 10/45/45 weight percent cement/slag/fly ash with a water to premix ratio of 0.60 is recommended for the Clean Cap. Although this mix may generate more than 3 volume percent standing water (bleed water), it has rheological, mixing and flow properties that are similar to previously processed Saltstone. The recommended

  14. Mechanical compaction in Bleurswiller sandstone: effective pressure law and compaction localization

    Science.gov (United States)

    Baud, Patrick; Reuschlé, Thierry; Ji, Yuntao; Wong, Teng-fong

    2016-04-01

    We performed a systematic investigation of mechanical compaction and strain localization in Bleurswiller sandstone of 24% porosity. 70 conventional triaxial compression experiments were performed at confining pressures up to 200 MPa and pore pressures ranging from 5 to 100 MPa. Our new data show that the effective pressure principle can be applied in both the brittle faulting and cataclastic flow regimes, with an effective pressure coefficient close to but somewhat less than 1. Under relatively high confinement, the samples typically fail by development of compaction bands. X-ray computed tomography (CT) was used to resolve preexisting porosity clusters, as well as the initiation and propagation of the compaction bands in deformed samples. Synthesis of the CT and microstructural data indicates that there is no casual relation between collapse of the porosity clusters in Bleurswiller sandstone and nucleation of the compaction bands. Instead, the collapsed porosity clusters may represent barriers for the propagation of compaction localization, rendering the compaction bands to propagate along relatively tortuous paths so as to avoid the porosity clusters. The diffuse and tortuous geometry of compaction bands results in permeability reduction that is significantly lower than that associated with compaction band formation in other porous sandstones. Our data confirm that Bleurswiller sandstone stands out as the only porous sandstone associated with a compactive cap that is linear, and our CT and microstructural observation show that it is intimately related to collapse of the porosity clusters. We demonstrate that the anomalous linear caps and their slopes are in agreement with a micromechanical model based on the collapse of a spherical pore embedded in an elastic-plastic matrix that obeys the Coulomb failure criterion.

  15. Study on the Relationship Between the P-Wave Velocity and Strength of Compacted Expansive Soil%压实膨胀土纵波速度与强度的关系研究

    Institute of Scientific and Technical Information of China (English)

    黄震; 韦秉旭

    2014-01-01

    Ultrasonic technology was used to test p-wave velocity of the compacted expansive soil under the condition of constant amplitude wetting and drying cycle,the relationship of the p-wave velocity change value and the direct shear strength index was explored.The experimental results showed that;With the increase of cycling times,the p-wave velocity and cohesion of c values of compacted expansive soil are the attenuation trend,when the cycle amplitude greater,the attenuation degree of the p-wave velocity and cohesion of the c value is greater.The cohesion c value and longitudinal wave velocity of expansive soil has a good logarithmic decrement relation,the p-wave velocity and angle of internal friction values does not exist a certain functional relation.%利用超声波技术测试压实膨胀土在等幅度干湿循环条件下的纵波速度,探索了纵波波速变化值与直剪强度指标之间的关系。试验结果表明;随着循环次数的增加,压实膨胀土的纵波速度和黏聚力 c 值均呈衰减趋势,当循环幅度越大时,纵波速度和黏聚力c值衰减程度越大。膨胀土黏聚力c值和纵波速度具有良好的对数衰减关系,而纵波速度与内摩擦角φ值之间不存在某种函数关系。

  16. Compact Reactor

    International Nuclear Information System (INIS)

    Weyl's Gauge Principle of 1929 has been used to establish Weyl's Quantum Principle (WQP) that requires that the Weyl scale factor should be unity. It has been shown that the WQP requires the following: quantum mechanics must be used to determine system states; the electrostatic potential must be non-singular and quantified; interactions between particles with different electric charges (i.e. electron and proton) do not obey Newton's Third Law at sub-nuclear separations, and nuclear particles may be much different than expected using the standard model. The above WQP requirements lead to a potential fusion reactor wherein deuterium nuclei are preferentially fused into helium nuclei. Because the deuterium nuclei are preferentially fused into helium nuclei at temperatures and energies lower than specified by the standard model there is no harmful radiation as a byproduct of this fusion process. Therefore, a reactor using this reaction does not need any shielding to contain such radiation. The energy released from each reaction and the absence of shielding makes the deuterium-plus-deuterium-to-helium (DDH) reactor very compact when compared to other reactors, both fission and fusion types. Moreover, the potential energy output per reactor weight and the absence of harmful radiation makes the DDH reactor an ideal candidate for space power. The logic is summarized by which the WQP requires the above conditions that make the prediction of DDH possible. The details of the DDH reaction will be presented along with the specifics of why the DDH reactor may be made to cause two deuterium nuclei to preferentially fuse to a helium nucleus. The presentation will also indicate the calculations needed to predict the reactor temperature as a function of fuel loading, reactor size, and desired output and will include the progress achieved to date

  17. Application of the Modified Compaction Material Model to the Analysis of Landmine Detonation in Soil with Various Degrees of Water Saturation

    OpenAIRE

    Grujicic, M.; B. Pandurangan; Summers, J.D.; B.A. Cheeseman; W.N. Roy; R.R. Skaggs

    2008-01-01

    A series of transient non-linear dynamics computational analyses of the explosion phenomena accompanying the detonation of a 100g C4 mine buried in sand to different depths is carried out using the software package AUTODYN. The mechanical response of sand under high deformation-rate conditions has been represented using the modified compaction material model developed in our recent work [1]. While the mechanical response of the other attendant materials (air, gaseous-detonation products and A...

  18. 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

  19. Traffic soil compaction of an oxisol related to soybean development and yield Compactação de um latossolo devido ao tráfego relacionado ao desenvolvimento e produtividade de soja

    Directory of Open Access Journals (Sweden)

    Amauri Nelson Beutler

    2007-12-01

    Full Text Available Excessive traffic on the soil may affect soybean development. This research was carried out to evaluate soybean root development and grain yield under compacted soil, in an Oxisol. The following traffic treatments were used: T0 = no traffic; T1* = 1 passage of a 4 t tractor; and, T1, T2, T4 and T6, respectively for 1, 2, 4 and 6 passages of an 11 t tractor on the same location, each besides the other. After compaction, soybean [Glycine max cv. MG/BR 46 (Conquista] was cultivated. The experiment was arranged in a completely randomized design, with six compaction levels and four replicates (plots of 9.0 m². Undisturbed soil samples were collected in the layers 0.03-0.06, 0.08-0.11, 0.15-0.18 and 0.22-0.25 m, for physical analyses. Root analyses were performed at layers of 0.0-0.10, 0.10-0.15 and 0.20-0.25 m. Soil compaction decreased deep root development and did not affect root amount, but its distribution. Yield decreased at the penetration resistance of 2.33 MPa or higher, and soil bulk density of 1.51 Mg m-3 or higher.O tráfego excessivo de máquinas sobre o solo pode prejudicar o desenvolvimento da cultura da soja. Assim, o objetivo deste estudo foi avaliar o desenvolvimento radicular e a produtividade da soja em função da compactação. O experimento foi realizado em Latossolo Vermelho de textura média. Os tratamentos de compactação foram: T0 = sem tráfego; T1* = 1 passada de trator de 4 t; e, T1, T2, T4 e T6, respectivamente, para 1, 2, 4 e 6 passadas de um trator de 11 t, no mesmo local, uma ao lado da outra. Após a compactação foi semeado o cultivar de soja (Glycine max MG/BR 46 (Conquista.O delineamento experimental foi inteiramente casualizado, com seis níveis de compactação e quatro repetições (parcelas de 9,0 m². Foram coletadas amostras indeformadas de solo nas camadas de 0,03-0,06; 0,08-0,11; 0,15-0,18 e 0,22-0,25 m, para determinação dos atributos físicos. As raízes foram avaliadas nas camadas de 0,0-0,10; 0

  20. Biofilm treatment of soil for waste containment and remediation

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.P.; Dennis, M.L.; Osman, Y.A.; Chase, J.; Bulla, L.A. [Univ. of Wyoming, Laramie, WY (United States)

    1997-12-31

    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{sub sat} using a flexible-wall permeameter. Saturated hydraulic conductivity (k{sub sat}) was reduced from 1 x 10{sup -5} cm/sec to 2 x 10{sup -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{sub 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.

  1. Crescimento aéreo e radicular da soja e de plantas de cobertura em camadas compactadas de solo Shoot and root growth of soybean and cover crops as affected by soil compaction

    Directory of Open Access Journals (Sweden)

    José Salvador Simoneti Foloni

    2006-02-01

    Full Text Available O cultivo de plantas de cobertura com sistema radicular vigoroso em rotação de culturas pode melhorar a qualidade física de solos compactados. O objetivo deste trabalho foi avaliar o crescimento aéreo e radicular da soja e de cinco espécies utilizadas como plantas de cobertura de verão (guandu, guandu anão, mucuna preta, labe labe e crotalária juncea, em solo submetido a três níveis de compactação em subsuperfíce. Utilizou-se um Nitossolo Vermelho argiloso em vasos montados com anéis de PVC sobrepostos, com diâmetro interno de 20 cm e altura de 50 cm. A camada compactada localizada de 20-30 cm de profundidade foi caracterizada pelas densidades do solo de 1,13, 1,34 e 1,56 g cm-3 e 0,26, 0,66 e 1,98 MPa de impedância mecânica, respectivamente. Aos 60 dias da emergência das plantas, determinaram-se as massas da matéria seca da parte aérea e das raízes, a densidade do comprimento radicular e o diâmetro médio radicular. Apesar de alterar a distribuição do sistema radicular ao longo do perfil do solo, o impedimento físico em subsuperfície não diminuiu a produção total de raízes da soja e dos adubos verdes, com exceção da crotalária juncea. A mucuna preta foi a leguminosa mais tolerante e a soja a mais sensível à compactação do solo. O sistema radicular da crotalária juncea apresentou potencial de formação de "bioporos" compatível ao da mucuna preta, apesar de ter sido relativamente mais sensível à compactação do solo. O diâmetro médio das raízes da soja e da crotalária juncea apresentou correlação significativa com o crescimento radicular dentro da camada de solo compactado.The cultivation of cover crops with vigorous root systems in crop rotation can improve the physical quality of compacted soils. The objective of this study was to evaluate shoot and root growth of soybean (Glycine max and five species used as summer cover crops (Cajanus cajan, Cajanus cajan var. small, Mucuna aterrima, Dolichos

  2. Technology Selections for Cylindrical Compact Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Phillips

    2010-10-01

    A variety of process approaches are available and have been used historically for manufacture of cylindrical fuel compacts. The jet milling, fluid bed overcoating, and hot press compacting approach being adopted in the U.S. AGR Fuel Development Program for scale-up of the compacting process involves significant paradigm shifts from historical approaches. New methods are being pursued because of distinct advantages in simplicity, yield, and elimination of process mixed waste. Recent advances in jet milling technology allow simplified dry matrix powder preparation. The matrix preparation method is well matched with patented fluid bed powder overcoating technology recently developed for the pharmaceutical industry and directly usable for high density fuel particle matrix overcoating. High density overcoating places fuel particles as close as possible to their final position in the compact and is matched with hot press compacting which fully fluidizes matrix resin to achieve die fill at low compacting pressures and without matrix end caps. Overall the revised methodology provides a simpler process that should provide very high yields, improve homogeneity, further reduce defect fractions, eliminate intermediate grading and QC steps, and allow further increases in fuel packing fractions.

  3. 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

  4. 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.

  5. Study on electrical monitoring of fill-up improvement. Utilization of resistivity data for soil compaction management; Hiteiko mitsudo kanri ni kansuru kisoteki kenkyu. Moritsuchi seko kanri eno hiteiko yuko riyo

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, N.; Hiramatsu, W. [Dai Nippon Construction, Gifu (Japan); Sugano, T. [Kyoto University, Kyoto (Japan). Faculty of Engineering

    1996-10-01

    At present, measurement of wet density and water content by radio isotope (RI method) is used for filling management. It is supposed for filling in road construction that putting-out thickness of banking material reaches nearly 1m in the future rapid construction, however, use of RI method is difficult because of inserting and installing of a radiation source rod, large measuring apparatus, and the legal regulation on radioactivity intensity. Application of resistivity measurement was thus considered. Since resistivity has the same parameter as compaction curve, and monotonously decreases with an increase in water content by volume, it is applicable as construction management index. The management reference of resistivity (Rm) is set by plotting of a compaction curve and corresponding resistivity curve, determination of the reference resistivity (Ro) corresponding to a maximum dry density and optimum water content ratio, and setting of the allowance to Ro according to soil or application. It was clarified that Rm is applicable as set for every filling material. 1 ref., 10 figs., 2 tabs.

  6. Soil compaction and eucalyptus growth in response to forwarder traffic intensity and load Compactação do solo e crescimento de eucalipto influenciados pela intensidade de tráfego e carga de um forwarder

    Directory of Open Access Journals (Sweden)

    Sérgio Ricardo da Silva

    2008-06-01

    Full Text Available During timber exploitation in forest stands harvesting machines pass repeatedly along the same track and can cause soil compaction, which leads to soil erosion and restricted tree root growth. The level of soil compaction depends on the number of passes and weight of the wood load. This paper aimed to evaluate soil compaction and eucalyptus growth as affected by the number of passes and wood load of a forwarder. The study was carried out in Santa Maria de Itabira county, Minas Gerais State - Brazil, on a seven-year-old eucalyptus stand planted on an Oxisol. The trees were felled by chainsaw and manually removed. Plots of 144 m² (four rows 12 m long in a 3 x 2 m spacing were then marked off for the conduction of two trials. The first tested the traffic intensity of a forwarder which weighed 11,900 kg and carried 12 m³ wood (density of 480 kg m-3 and passed 2, 4, and 8 times along the same track. In the second trial, the forwarder carried loads of 4, 8, and 12 m³ of wood, and the machine was driven four times along the same track. In each plot, the passes affected four rows. Eucalyptus was planted in 30 x 30 x 30 cm holes on the compacted tracks. The soil in the area is clayey (470 clay and 440 g kg-1 sand content and at depths of 0-5 cm and 5-10 cm, respectively, soil organic carbon was 406 and 272 g kg-1 and the moisture content during the trial 248 and 249 g kg-1. These layers were assessed for soil bulk density and water-stable aggregates. The infiltration rate was measured by a cylinder infiltrometer. After 441 days the measurements were repeated, with additional analyses of: soil organic carbon, total nitrogen, N-NH4+, N-NO3-, porosity, and penetration resistance. Tree height, stem diameter, and stem dry matter were measured. Forwarder traffic increased soil compaction, resistance to penetration and microporosity while it reduced the geometric mean diameter, total porosity, macroporosity and infiltration rate. Stem dry matter yield and

  7. Numerical simulation of dynamic characteristics of soil under role of strong compaction%强夯作用下土体动力特性的数值模拟

    Institute of Scientific and Technical Information of China (English)

    向泽华; 胡焕校; 吴高权

    2015-01-01

    in order to further study the interaction between hammer and soil in the process of dynamic com -paction, the paper used the finite element method to simulate the whole process .In the process of simula-tion, it adopted the finite element software ANSYS/LS -DYNA and thought the factors such as material nonlinear , large deformation and etc .Finally it got the variable curves of dynamic stress and displacement of soil with in the process of dynamic compaction and summarized the variable rule and distributing charac -teristics .The results of numerical simulation are basically consistent with the experimental data at the con -struction site .The rsult can provide reference for the design and construction of dynamic compaction .%为了更加深入研究在强夯过程中夯锤与地基土的相互作用,运用有限元法模拟了整个强夯过程。在模拟过程中采用ANSYS/LS-DYNA有限元软件,同时将材料的非线性、大变形等因素考虑到模拟过程中,得到强夯过程中土体动应力和位移的变化曲线,并总结其变化规律和分布特征。数值模拟的结果与施工现场的实验数据基本一致,可以为强夯的设计与施工提供参考依据。

  8. Compactação de um latossolo vermelho distroférrico com diferentes quantidades e manejos de palha em superfície Soil compaction in a rhodic hapludox soil as influenced by straw management and quantity on surface

    Directory of Open Access Journals (Sweden)

    Daniel Coelho Rosim

    2013-01-01

    Full Text Available A compactação do solo em áreas agrícolas manejadas em sistema plantio direto tem sido apontada como um problema enfrentado por produtores, em especial nas áreas com solos argilosos. A compactação é causada principalmente pelo tráfego de máquinas, quando não são respeitadas faixas adequadas de umidade do solo. A palha na superfície do solo, por criar uma barreira física entre o pneu das máquinas e o solo, pode ser um fator de minimização da compactação. Assim, o objetivo do estudo foi avaliar o efeito da palha de milheto em superfície na redução da compactação do solo causada pelo rodado de um trator. O experimento constou de quatro tratamentos de quantidade de palha (sem palha, 5, 10 e 15 Mg ha-1 e três de manejo da palha (em pé, tombada e fragmentada. Após a passagem do trator determinou-se a resistência à penetração, umidade, densidade e porosidade total do solo na área trafegada. A densidade e porosidade total não foram afetadas pela passagem do tráfego. Nos tratamentos com palha, obteve-se maior umidade e, consequentemente, menor resistência. Entre os tratamentos de manejo da palha não houve diferença para umidade e resistência. Para a mesma umidade do solo, maiores quantidades de palha resultaram em menores valores de resistência à penetração, evidenciando menor compactação.Soil compaction in areas under no-tillage has been pointed as a problem faced by farmers, particularly in areas with clay soils. Compaction is mainly caused by machinery traffic when the adequate soil moisture is not respected. Straw on the soil surface, by creating a physical barrier between the wheel and the ground may be a factor to minimize compaction. Therefore, the objective of this study was to evaluate the effect of millet straw on soil surface in reducing compaction caused by the tractor wheels. The experiment consisted of four treatments of straw quantity on surface (without straw and 5, 10 and 15 Mg ha-1 and three

  9. Compactação de um latossolo vermelho distroférrico com diferentes quantidades e manejos de palha em superfície Soil compaction in a rhodic hapludox soil as influenced by straw management and quantity on surface

    Directory of Open Access Journals (Sweden)

    Daniel Coelho Rosim

    2012-01-01

    Full Text Available A compactação do solo em áreas agrícolas manejadas em sistema plantio direto tem sido apontada como um problema enfrentado por produtores, em especial nas áreas com solos argilosos. A compactação é causada principalmente pelo tráfego de máquinas, quando não são respeitadas faixas adequadas de umidade do solo. A palha na superfície do solo, por criar uma barreira física entre o pneu das máquinas e o solo, pode ser um fator de minimização da compactação. Assim, o objetivo do estudo foi avaliar o efeito da palha de milheto em superfície na redução da compactação do solo causada pelo rodado de um trator. O experimento constou de quatro tratamentos de quantidade de palha (sem palha, 5, 10 e 15 Mg ha-1 e três de manejo da palha (em pé, tombada e fragmentada. Após a passagem do trator determinou-se a resistência à penetração, umidade, densidade e porosidade total do solo na área trafegada. A densidade e porosidade total não foram afetadas pela passagem do tráfego. Nos tratamentos com palha, obteve-se maior umidade e, consequentemente, menor resistência. Entre os tratamentos de manejo da palha não houve diferença para umidade e resistência. Para a mesma umidade do solo, maiores quantidades de palha resultaram em menores valores de resistência à penetração, evidenciando menor compactação.Soil compaction in areas under no-tillage has been pointed as a problem faced by farmers, particularly in areas with clay soils. Compaction is mainly caused by machinery traffic when the adequate soil moisture is not respected. Straw on the soil surface, by creating a physical barrier between the wheel and the ground may be a factor to minimize compaction. Therefore, the objective of this study was to evaluate the effect of millet straw on soil surface in reducing compaction caused by the tractor wheels. The experiment consisted of four treatments of straw quantity on surface (without straw and 5, 10 and 15 Mg ha-1 and three

  10. ICESat Estimates of Elevation and Volume Changes of Greenland Ice Caps

    Science.gov (United States)

    Robbins, J. W.; Zwally, J.; Yi, D.; Li, J.; Saba, J. L.

    2012-12-01

    ICESat Laser Altimetry acquired over the period 2003-2008 has been processed to provide estimates of changes in elevation for each aligned laser footprint. These are then interpolated, geographically, yielding estimates of volume change on nearly two dozen peripheral ice caps, mostly located in northern Greenland. Definition of ice cap edges are provided by the Greenland Mapping Project 90m, high-resolution, ice mask (GIMP). The results provide a geometric measure of sub-decadal ice cap gain or loss, with the outcome being that more ice caps are losing volume than gaining. Ice caps ranging in size from 200 to 7500 square km have been considered. Over the five-years, ice cap volume changes range from -1.586 cubic km for the Ikke Opmålt cap (2965.1 sq. km areal extent) to +0.582 cubic km on the Kronprins Christian Land cap (7414.6 sq. km). The corresponding averaged rates of elevation change range from -0.535 m/yr to +0.079 m/yr, respectively. Estimates of elevation changes from variations in the rate of firn compaction are also applied. Additionally, examination of time histories of ICESat elevation profiles crossing select ice caps reveal seasonal losses and gains.

  11. Efeito do conteúdo de água e da compactação do solo na produção de soja Effect of water content and soil compaction in soybean production

    Directory of Open Access Journals (Sweden)

    Amauri Nelson Beutler

    2003-07-01

    Full Text Available A compactação do solo tem sido fator físico limitante ao crescimento das plantas. Este trabalho objetivou avaliar a produção de soja (Glycine max cv. EMBRAPA 48 em razão do conteúdo de água e da compactação do solo. Usou-se o delineamento inteiramente casualizado, em esquema fatorial 4x2, ou seja, quatro níveis de resistência à penetração (entre 0,27 e 4,32 MPa e dois níveis de retenção de água pelo solo (0,05 e 0,01 MPa. Foram utilizadas amostras de Latossolo Vermelho textura média (LVd e Latossolo Vermelho textura argilosa (LVef, coletadas na profundidade de 020 cm, passadas em peneira de 0,4 cm e compactadas em camadas de 3 cm, em vasos de 20 cm de altura e 25 cm de diâmetro (9,82 L. Os níveis de resistência à penetração foram determinados com o penetrômetro de anel dinamométrico. O nível crítico de resistência do solo à penetração, em relação à produção de grãos, foi de 1,66 e 2,22 MPa, no LVd, e 3,05 e 2,81 MPa, no LVef, para o conteúdo de água retida na tensão de 0,05 e 0,01 MPa, respectivamente. A maior produção de grãos foi obtida na tensão de 0,01 MPa. A produção de grãos de soja é afetada em níveis críticos de resistência do solo à penetração superiores a 2 MPa em latossolos com conteúdo de água retida na tensão de 0,01 MPa.Soil compaction has been limiting physical factor to plants growth. This work aimed to evaluate the production of soybean (Glycine max cv. EMBRAPA 48 as affected by water content and soil compaction. The experimental design was completely randomized, in a factorial scheme 4x2, i.e., four levels of resistance to penetration (between 0.27 and 4.32 MPa and two levels of soil water retention (0.05 and 0.01 MPa. Samples of Red Latossol medium texture and Red Latossol clayey were collected in 020 cm depth, sieved in mesh of 0.4 cm and compacted in layers of 3 cm in pots of 20 cm height and 25 cm of diameter (9.82 L. The levels of resistance to penetration were

  12. Hydraulic Conductivity of Compacted Laterite Treated with Iron Ore Tailings

    OpenAIRE

    Yusuf, Umar Sa’eed; Slim, Matawal Danladi; Uchechukwu, Elinwa Augustine

    2016-01-01

    The objective of this study was to investigate the effect of iron ore tailings (IOT) on hydraulic conductivity of compacted laterite. The IOT conforms to ASTM C 618-15 Type F designations. In the present study, soil was admixed with 0–20% IOT and compacted at moulding water content ranging from 10 to 25% using four types of compactive efforts. Hydraulic conductivities of the compacted soil-IOT mixtures were determined using deionized water and municipal solid waste leachate as the permeant fl...

  13. PROTOCOL FOR DETERMINING BIOAVAILABILITY AND BIOKINETICS OF ORGANIC POLLUTANTS IN DISPERSED, COMPACTED AND INTACT SOIL SYSTEMS TO ENHANCE IN SITU BIOREMEDIATION

    Science.gov (United States)

    The development of effective in situ and on-site bioremediation technologies can facilitate the cleanup of chemically-contaminated soil sites. Knowledge of biodegradation kinetics and bioavailability of organic pollutants can facilitate decisions on the efficacy of in situ and o...

  14. ATLAS - End-Cap calorimeter

    CERN Multimedia

    2006-01-01

    The End-cap calorimeter was moved with the help of the rails and this calorimeter will measure the energy of particles close to the beam axis when protons collide. Cooling is important for maximum detector efficiency.

  15. Researchers dodge UK migration cap

    Science.gov (United States)

    Dacey, James

    2011-03-01

    Research scientists are among those to be prioritized under the UK government's new immigration rules that will impose an annual cap on the number of work visas issued to those from outside the European Union (EU).

  16. Genetics Home Reference: cap myopathy

    Science.gov (United States)

    ... or a spine that curves to the side ( scoliosis ). The name cap myopathy comes from characteristic abnormal ... health conditions: Diagnostic Tests Drug Therapy Surgery and Rehabilitation Genetic Counseling Palliative Care Related Information How are ...

  17. Hydraulic Conductivity of Compacted Laterite Treated with Iron Ore Tailings

    Directory of Open Access Journals (Sweden)

    Umar Sa’eed Yusuf

    2016-01-01

    Full Text Available The objective of this study was to investigate the effect of iron ore tailings (IOT on hydraulic conductivity of compacted laterite. The IOT conforms to ASTM C 618-15 Type F designations. In the present study, soil was admixed with 0–20% IOT and compacted at moulding water content ranging from 10 to 25% using four types of compactive efforts. Hydraulic conductivities of the compacted soil-IOT mixtures were determined using deionized water and municipal solid waste leachate as the permeant fluids, respectively. Deionized water was the reference permeant fluid. Results of this study showed that hydraulic conductivity decreased with increase in IOT content as a result of improvement in mechanical properties of the soil. Permeation of the soil-IOT mixtures with leachate caused the hydraulic conductivity to drop to less than 1 × 10−9 m/s especially at higher compactive efforts. Also, bioclogging of the soil pores due to accumulation of biomass from bacteria and yeast present in the leachate tends to significantly reduce the hydraulic conductivity. From an economic point of view, it has been found from the results of this study that soil specimens treated with up to 20% IOT and compacted at the British Standard Light (BSL compactive effort met the maximum regulatory hydraulic conductivity of less than or equal to 1 × 10−9 m/s for hydraulic barrier system.

  18. Desenvolvimento de mudas de aceroleira propagadas por estacas e sementes em solo compactado Development of West Indian Cherry plants development propagated by cuttings or seeds in soil compacted

    Directory of Open Access Journals (Sweden)

    Ivan Bordin

    2005-06-01

    Full Text Available O trabalho teve como objetivo avaliar o desenvolvimento da parte aérea e do sistema radicular de mudas de aceroleira (Malpighia emarginata D.C. propagadas por sementes e por estacas, sob níveis de compactação subsuperficial de solo. Foram montados vasos com 200 mm de diâmetro e 285 mm de altura, divididos em três anéis sobrepostos de 100, 35 e 150 mm. O solo do anel intermediário foi submetido a quatro níveis de densidade (1,0; 1,2 1,4 e 1,6kg dm-3. O experimento foi conduzido com delineamento experimental de blocos ao acaso, num esquema fatorial de 2 x 4 (duas formas de propagação e quatro densidades de solo, com cinco repetições. O aumento da densidade do solo propicia um maior desenvolvimento da parte aérea e raízes das mudas propagadas por estacas em relação às propagadas por sementes. Independente da forma de propagação utilizada, os níveis de densidade do solo avaliados não impedem a penetração das raízes de aceroleira.The objective of this research work was to evaluate West Indian Cherry (Malpighia emarginata D.C. above-ground and root system development, in plants propagated by seeds and cuttings at different soil density levels ( 1,0; 1,2; 1,4 and 1,6kg dm-3. The experiment was carried out in pots with 200 mm diameter and 285 mm height, divided in three rings with 100, 35 and 150 mm height. The experimental design was totally randomized in a factorial arrangement 2 x 4 (two propagation forms and four soil densities with five replications. The increase in soil density improved a higher above-ground parts and roots development in plants propagated by cuttings. Independent of the propagation method, the studied soil density levels did not prevent the root penetration.

  19. Resistência à compactação de um Latossolo cultivado com cafeeiro, sob diferentes sistemas de manejo de plantas invasoras Resistance to soil compaction of an Oxisol cultivated with coffee plants under different weed Management systems

    Directory of Open Access Journals (Sweden)

    Cezar Francisco Araujo-Junior

    2008-02-01

    ção.The knowledge of the pressure levels that can be applied to the soil under different weed management system (WMS is importante for coffee plantations management. The objective of this study was to evaluate the influence of different weed management systems on the susceptibility to compaction of a Red-Yellow Latossol (Oxisol (LVA using soil support capacity (CSC models. This study was carried out at the Epamig Research Farm in Patrocínio, state of Minas Gerais, Brazil, in a coffee plantation using Ruby 1192 coffee variety in a 3.8 x 0.7 m spacing, planted in February 1999. Four WMS were used and the soil samples were collected in-between the rows under the following management systems: (1 no weed control (SC; (2 hoe-weeded (CM; (3 weed control with post-emergence herbicide Glyphosate (HPÓS; (4 weed control with pre-emergence Oxyfluorfen (HPRÉ. Fifteen undisturbed soil samples from each system were collected (in the layers 0-3, 10-13 and 25-28 cm in July 2004, totaling 180 samples. The undisturbed soil samples were equilibrated at different moisture contents and subjected to the uniaxial compression test to obtain the soil CSC models. Results suggested that the support capacity of the LVA decreases in the center of the inter rows in the following order: HPRÉ in the 0-3 cm layer > CM in the 10-13 cm layer > SC in the 0-3, 10-13, 25-28 cm layers = HPÓS in the 0-3, 10-13, 25-28 cm layers = CM at 0-3 and 25-28 cm layers = HPRÉ in the 10-13 cm layer > HPRÉ in the 25-28 cm layer. Weed control with HPRÉ in the 25-28 cm layer was most susceptible, while HPRÉ in the 0-3 cm layer was most resistant to soil compaction. The management systems SC and HPÓS in the 0-3, 10-13, 25-28 cm layers and the managements CM in the 0-3 and 25-28 cm layers and HPRÉ in the 10-13 cm layer were equally susceptible to soil compaction.

  20. The influence of saturation on the cracking process in compacted desiccating clays

    Directory of Open Access Journals (Sweden)

    Noack Maria

    2016-01-01

    Full Text Available Tensile failure in unsaturated cohesive soils during desiccation is important for the design of geotechnical applications such as capping systems of landfills and sealing material of dikes. This study presents the results of different initial parameters of compacted clay samples such as gravimetric water content, dry density and degree of saturation. These parameters are varied systematically for each test to find the correlation between those parameters and the tensile failure. The tensile failure for all tests occurred by a comparable constant change of the degree of saturation. The soil specific saturation ratio Sr,s is defined as the quotient of saturation changes ΔSr to initial saturation Sr,0. This parameter related to the total suction shows an equal course for all results. All in all, the course of the soil specific saturation ratio Sr,s is independent of all initial parameters. These results provide a physical and hydraulic-mechanical description for modelling the desiccation process. To demonstrate the initiation and progress of tensile failure, the experimental results are modelled with a Discrete Element Method (DEM approach.

  1. Shales and swelling soils

    Science.gov (United States)

    Franklin, J. A.; Dimillio, A. F.; Strohm, W. E., Jr.; Vandre, B. C.; Anderson, L. R.

    The thirteen (13) papers in this report deal with the following areas: a shale rating system and tentative applications to shale performance; technical guidelines for the design and construction of shale embankments; stability of waste shale embankments; dynamic response of raw and stabilized Oklahoma shales; laboratory studies of the stabilization of nondurable shales; swelling shale and collapsing soil; development of a laboratory compaction degradation test for shales; soil section approach for evaluation of swelling potential soil moisture properties of subgrade soils; volume changes in compacted clays and shales on saturation; characterization of expansive soils; pavement roughness on expansive clays; and deep vertical fabric moisture barriers in swelling soils.

  2. 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.

  3. Capping of rare earth silicide nanowires on Si(001)

    International Nuclear Information System (INIS)

    The capping of Tb and Dy silicide nanowires grown on Si(001) was studied using scanning tunneling microscopy and cross-sectional high-resolution transmission electron microscopy. Several nanometers thick amorphous Si films deposited at room temperature allow an even capping, while the nanowires maintain their original structural properties. Subsequent recrystallization by thermal annealing leads to more compact nanowire structures and to troughs in the Si layer above the nanowires, which may even reach down to the nanowires in the case of thin Si films, as well as to V-shaped stacking faults forming along (111) lattice planes. This behavior is related to strain due to the lattice mismatch between the Si overlayer and the nanowires

  4. Capping of rare earth silicide nanowires on Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Appelfeller, Stephan; Franz, Martin; Kubicki, Milan; Dähne, Mario [Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin (Germany); Reiß, Paul; Niermann, Tore; Lehmann, Michael [Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin (Germany); Schubert, Markus Andreas [IHP–Leibniz-Institut für innovative Mikroelektronik, 15236 Frankfurt (Oder) (Germany)

    2016-01-04

    The capping of Tb and Dy silicide nanowires grown on Si(001) was studied using scanning tunneling microscopy and cross-sectional high-resolution transmission electron microscopy. Several nanometers thick amorphous Si films deposited at room temperature allow an even capping, while the nanowires maintain their original structural properties. Subsequent recrystallization by thermal annealing leads to more compact nanowire structures and to troughs in the Si layer above the nanowires, which may even reach down to the nanowires in the case of thin Si films, as well as to V-shaped stacking faults forming along (111) lattice planes. This behavior is related to strain due to the lattice mismatch between the Si overlayer and the nanowires.

  5. H型长钢桩尖在密实土层中的应用%Application of long H?type steel pile tip in compact soil layer

    Institute of Scientific and Technical Information of China (English)

    孟晓宁; 于云山

    2016-01-01

    在钢筋混凝土桩基施工时,如果遇到工程区域地质持力层较密实且埋藏较浅或者持力层上面有较密实的覆盖层的情况,往往会造成沉桩困难、桩的入土深度不能满足使用要求等问题.结合具体工程的实践经验对此类工程问题进行分析,提出钢筋混凝土桩组合H型长钢桩尖的解决方案,并与普通钢筋混凝土桩基方案进行对比、通过计算及试桩试验对方案进行验证、对方案优点及适用性进行总结.%During the reinforced concrete pile foundation construction process, when the bearing stratum of engineering region is more compact and shallow buried or be covered by dense layer, the problems are tend to hap?pen, such as pile?sinking difficultly or embedded depth of pile cannot meet operating requirement. Combined with specific engineering practice experience and the analysis of such problems, the solution of reinforced concrete pile with long H?type steel pile tip was mentioned in this paper. The advantage and applicability of this solution was summarized by contrast with common reinforced concrete pile foundation, and it was verified by calculation and test piles.

  6. 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

  7. Creation of polar cap patches

    Science.gov (United States)

    Hosokawa, K.; Taguchi, S.; Ogawa, Y.

    2014-12-01

    Polar cap patches, which are islands of enhanced plasma density drifting anti-sunward, are one of the outstanding phenomena in the polar cap F region ionosphere. In the last decade, data from all-sky airglow imagers have been extensively used for better understanding the propagation of patches in the central polar cap region. But still, it has been rather difficult to capture the birth of patches in their generation region near the dayside cusp, because, in most places, the dayside part of the polar cap ionosphere is sunlit even in winter. In Longyearbyen (78.1N, 15.5E), Norway, however, optical observations are possible near the dayside cusp region in a limited period around the winter solstice. This enables us to directly image how polar cap patches are born in the cusp. In this paper, we present a few intervals of daytime optical observations, during which polar cap patches were generated within the field-of-view of an all-sky imager in Longyearbyen. During all the intervals studied here, we identified several signatures of poleward moving auroral forms (PMAF) in the equatorward half of the field-of-view, which are known as ionospheric manifestations of dayside reconnection. Interestingly, patches were directly produced from such poleward moving auroral signatures and propagated poleward along the anti-sunward convection near the cusp. In the literature, Lorentzen et al. (2012) first reported such a direct production of patches from PMAFs. During the current observations, however, we succeeded in tracking the propagation of patches until they reached the poleward edge of the field-of-view of the imager. This confirms that the faint airglow structures produced from PMAFs were actually transported for a long distance towards the central polar cap area; thus, polar cap patches were produced. From this set of observations, we suggest that polar cap patches during moderately disturbed conditions (i.e, non-storm time conditions) can be directly produced by the

  8. Substrates to contrast compaction in urban tree plantings

    OpenAIRE

    Pini, Roberto; Bretzel, Francesca; Cinelli, Fabrizio

    2011-01-01

    Aim of our work was to assess the ability of recycled crushed bricks employed as a substrate of growth, of contrasting the compaction and improving the development of trees in urban avenues. Soil employed in urban planting is often deep subsoil with a high percentage of fine material (silt and clay) and no organic matter. The excess of soil compaction due to trampling and car parking can seriously affect the survival of trees in these conditions. Coarse recycled materials already used in urba...

  9. The North Zealand CAP Monitor

    DEFF Research Database (Denmark)

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

    2016-01-01

    nurses and two senior doctors. Direct observations of the clinical processes revealed problems of coordination, complex disease trajectories that did not fit with the pneumonia pathway, unclear guidelines and variation in their interpretation. Intervention We designed a measurement system to monitor...... patients with CAP and effects of interventions to improve the quality of their care. Based on current literature we defined and tested a set of indicators and designed an audit form, a database and a dashboard for presenting the results. Two nurses monthly audited randomly selected files of patients...... steps of the pneumonia pathway. Lessons learnt Quality of care for CAP was worse than expected. Defining and agreeing upon a set of indicators was difficult and time consuming but useful to improve our understanding of how care for CAP was in routine clinical practice. Several indicators we initially...

  10. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; OUCHI, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  11. Mechanics of tissue compaction.

    Science.gov (United States)

    Turlier, Hervé; Maître, Jean-Léon

    2015-12-01

    During embryonic development, tissues deform by a succession and combination of morphogenetic processes. Tissue compaction is the morphogenetic process by which a tissue adopts a tighter structure. Recent studies characterized the respective roles of cells' adhesive and contractile properties in tissue compaction. In this review, we formalize the mechanical and molecular principles of tissue compaction and we analyze through the prism of this framework several morphogenetic events: the compaction of the early mouse embryo, the formation of the fly retina, the segmentation of somites and the separation of germ layers during gastrulation.

  12. Experimental Study on Soil-Water Characteristics in Compacted Bentonite%压实膨润土的土水特性试验研究

    Institute of Scientific and Technical Information of China (English)

    沈忠; 王青海; 张永浩; 陈洁; 何艺峰; 刘艳

    2013-01-01

    回填材料是高放废物地质处置库多重屏障系统的重要组成部分,以蒙脱石为主要成分的膨润土是较理想的回填材料,研究膨润土的非饱和渗透特性,对于回填材料选材和处置库安全性评价具有重要意义.文章通过室内试验开展柯尔碱膨润土的土水特性研究,用压力膜仪实测不同干密度柯尔碱膨润土的土水特征曲线,根据柔性壁渗透仪测得的饱和导水率数据,采用Van Genuchten(1980)预测模型分别计算得到每种干密度膨润土在不同含水量及基质吸力条件下的非饱和导水率,建立了非饱和导水率与含水量、基质吸力的相关关系,对比分析干密度对曲线的影响.结果表明,干密度对柯尔碱膨润土的土水特征曲线有着明显的影响,在初始含水量相同的情况下,干密度较大的膨润土脱水速率比干密度较小的膨润土脱水速率慢,表现出较高的持水性能.柯尔碱膨润土的非饱和导水率随含水量减小和基质吸力增大皆呈非线性降低,干密度越小,非饱和导水率越大.%Buffer backfill material is an important part of multi-barrier system in HLW geological repository.Bentonite is an ideal buffer backfill material, which is mainly composed of montmorillonite.The research of bentonite's non-saturated hydraulic properties is important to backfill material selection and repository safety evaluation.Soil-water characteristics of cole alkali bentonite by laboratory tests were studied.Pressure plate extractors were used to measure soil-water characteristics curve of cole alkali bentonite of different densities.The saturated hydraulic conductivity of bentonite was tested by flexible-wall permeameter, and then unsaturated hydraulic conductivity in different water contents and matrix suction was calculated through Van Genuchten(l980) prediction model.Based on measurement and calculation, the correlation between unsaturated hydraulic conductivity and water content

  13. Microhole subsoiling decreasing soil compaction, and improving yield and seed quality of cotton%微孔深松耕降低土壤紧实度提高棉花产量与种籽品质

    Institute of Scientific and Technical Information of China (English)

    王慧杰; 郝建平; 冯瑞云; 南洋; 杨淑巧; 南建福

    2015-01-01

    长期传统耕作导致土壤紧实形成犁底层是影响农田土壤质量和作物生长的关键障碍因子之一。为解决这一问题,于2013年4月至2014年5月在山西运城南花农场开展为期1 a的大田试验,对比研究微孔深松耕技术和旋耕机旋耕15~20 cm的传统耕作方法对土壤紧实度以及棉籽品质性状和生长发育的影响。结果表明:微孔深松耕技术较传统耕作方式,棉花苗期犁底层40 cm处土壤紧实度由9069.70降低到558.80 kPa,吐絮期犁底层40 cm处的土壤紧实度由8089.70降低到1174.20 kPa,吐絮期0~40 cm土层中微孔深松耕土壤容重最大为1.05 g/cm3,传统耕作最大为1.56 g/cm3;在>30 cm土层中,微孔深松耕的总根量比传统耕作方式多187.03%;微孔深松耕处理棉株棉铃的5室铃率较传统耕作增加15.00%,每个棉瓤的种子数平均增加1~2粒;棉籽的籽指、密度、绒长均明显增加,脂肪含量显著降低(P20 cm depth. At the boll opening stage, soil compaction increased slowly up to 1 174.2 kPa in microhole-subsoiled plots, while that in control plots reached a maximum of 8 089.7 kPa. Meanwhile, soil bulk density in microhole-subsoiled plots remained lower and decreased from 1.56 to 1.05 g/cm3 at>35-40 cm depth. Owing to the loosening of deeper soil, microhole subsoiling effectively induced cotton roots to go deeper. The main root reached the depth of over 80 cm depth in microhole-subsoiled plots and<70 cm depth in control plots. At the depth of below 30 cm, microhole subsoiling doubled root biomass (19.77%of total root biomass) and increased lateral roots (32.62% of total lateral root) compared with the control (9.81% of total root biomass and 19.42%of total lateral root). The 5-room boll rate was 15%higher and the number of seeds per cotton pulp was greater by from 1 to 2 in microhole-subsoiled plots than in control plots. At the second and fifth seed positions, cotton seed index

  14. From Blogs to Bottle Caps

    Science.gov (United States)

    Edinger, Ted

    2012-01-01

    There is a wonderful community of art educators connecting a once-isolated profession through blogging. Art educators around the world are sharing ideas and communicating with their peers through this amazing resource. In this article, the author describes the bottle cap mural at Tulip Grove Elementary School which was inspired by this exchange of…

  15. Compaction properties of isomalt

    NARCIS (Netherlands)

    Bolhuis, Gerad K.; Engelhart, Jeffrey J. P.; Eissens, Anko C.

    2009-01-01

    Although other polyols have been described extensively as filler-binders in direct compaction of tablets, the polyol isomalt is rather unknown as pharmaceutical excipient, in spite of its description in all the main pharmacopoeias. In this paper the compaction properties of different types of ispoma

  16. Efeitos da compactação em algumas propriedades físicas do solo e seu reflexo no desenvolvimento das raízes de plantas de soja Effects of soil compaction on some physical properties and on root growth of soybean

    Directory of Open Access Journals (Sweden)

    Maria Helena Moraes

    1995-01-01

    Full Text Available Estudou-se o efeito de vários níveis de compactação na densidade do solo, porosidade total e resistência à penetração, objetivando determinar o nível que impede o desenvolvimento das raízes de plantas de soja. O trabalho foi realizado em casa de vegetação, com amostras deformadas do horizonte superficial de uma terra roxa estruturada e de um latossolo roxo, controlando os níveis de compactação e o teor de água. A influência da compactação no desenvolvimento das raízes foi avaliada um mês após a germinação. Os valores de densidade do solo, para um mesmo nível de compactação, foram maiores para a terra roxa estruturada. O teor de água ótimo para a compactação foi de 21,0% para a terra roxa estruturada e de 29,8 para o latossolo roxo. A compactação artificial do solo acarretou aumento da resistência à penetração e diminuição da porosidade total. A elevação da sua densidade de 0,90 para 1,30 kg/m³ para a terra roxa estruturada, e de 0,90 para 1,23 kg/m³ para o latossolo roxo, promoveu, respectivamente, diminuição de 39 e de 41% na massa seca das raízes. O desenvolvimento das raízes das plantas ficou impedido quando a densidade do solo atingiu valores de 1,30 e 1,23 kg/m³, respectivamente, para a terra roxa estruturada e o latossolo roxo.The effects of an artificial soil compaction on soil density, total porosity and soil resistance to penetration were studied with the aim to determine the level that obstructs root development of soybean. The work was carried out in greenhouse, with disturbed samples of surface horizon of an Ultisol ("Terra Roxa Estruturada" and an Oxisol ("Latossolo Roxo", and controlling the level of compaction and the soil water content. The influence of soil compaction on root growth of soybean was evaluated one month after germination. The Ultisol showed higher soil density values than the Oxisol for the same compaction level. The optimum soil water content value for compaction was

  17. ATLAS End Cap toroid in upstanding position

    CERN Multimedia

    2005-01-01

    End Cap toroid The ATLAS End Cap toroid weights 240-ton and is 12-m diameter high. The parts of this vacuum vessel had to be integrated and tested so that End Cap Toroid has no leaks. After that it could be cooled down to 80 K.

  18. 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...

  19. 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...

  20. Dynamic Modeling of an Evapotranspiration Cap

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Steven Piet; Rafael Soto; Gerald Sehlke; Harold Heydt; John Visser

    2005-10-01

    The U.S. Department of Energy is scheduled to design and install hundreds of landfill caps/barriers over the next several decades and these caps will have a design life expectancy of up to 1,000 years. Other landfill caps with 30 year design lifetimes are reaching the end of their original design life; the changes to these caps need to be understood to provide a basis for lifetime extension. Defining the attributes that make a successful cap (one that isolates the waste from the environment) is crucial to these efforts. Because cap systems such as landfill caps are dynamic in nature, it is impossible to understand, monitor, and update lifetime predictions without understanding the dynamics of cap degradation, which is most often due to multiple interdependent factors rather than isolated independent events. In an attempt to understand the dynamics of cap degradation, a computer model using system dynamics is being developed to capture the complex behavior of an evapotranspiration cap. The specific objectives of this project are to capture the dynamic, nonlinear feedback loop structures underlying an evapotranspiration cap and, through computer simulation, gain a better understanding of long-term behavior, influencing factors, and, ultimately, long-term cap performance.

  1. 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...

  2. Biochars impact on water infiltration and water quality through a compacted subsoil layer

    Science.gov (United States)

    Soils in the Southeastern United States Coastal Plain region frequently have a compacted subsoil layer, which is a barrier for water movement. Four different biochars were evaluated to increase water movement through a compacted horizon from a Norfolk soil (fine-loamy, kaolinitic, thermic, Typic Ka...

  3. Efeito da compactação do solo sobre a semente no desenvolvimento da cultura do feijão = Effect of soil compaction upon the seed on the development of bean culture

    Directory of Open Access Journals (Sweden)

    Alcir José Modolo

    2011-01-01

    Full Text Available Um dos fatores da baixa produtividade está na dificuldade de se estabelecer a população ideal de plantas por ocasião da semeadura, pelos vários fatores que impedem a germinação normal de parte das sementes. Dentre os fatores primordiais para a germinação estão a umidade, a temperatura e a aeração do solo. É importante citar que estes fatores são diretamente influenciados pelo estado de compactação do solo ao redor da semente. O presente trabalho teve como objetivo estudar os efeitos da combinação entre profundidades desemeadura e cargas aplicadas pela roda compactadora da semeadora-adubadora sobre a emergência e o desenvolvimento da cultura do feijão, em sistema de plantio direto. Foi utilizado o esquema fatorial, no delineamento em blocos ao acaso composto por 12 tratamentos (três profundidades de semeadura e quatro níveis de cargas aplicadas pela roda compactadora e quatro repetições. Os resultados mostraram que a semeadura realizada a 5,0 cm de profundidade apresentou o melhor índice de velocidade-emergência, quando comparada às profundidades de 3,0 e 7,0 cm.One of the factors of low productivity is the difficulty of establishing the ideal population of plants at sowing time, due to the several factors that prevent the normal germination of part of the seeds. Among the primordial factors for germination are humidity,temperature, and airing of the soil. It is important to mention that these factors are directly influenced by the state of soil compaction around the seed. The present work aimed to study the effects of the combination between depths of sowing and loads applied by press wheel of the seeder on the emergence and development of bean culture, in no-tillage systems. The factorial scheme was applied, at the delineation in random blocks composed of twelve treatments (threedepths of sowing and four levels of loads applied by the press wheel and four replications. The results showed that the sowing performed at 5

  4. Traceability and the new CAP

    OpenAIRE

    Maraveyas, Napoleon N.; Doukas, Yannis El.

    2009-01-01

    The Common Agricultural Policy (CAP) was strongly criticized for the food safety crises of the 1990s which included Bovine Spongiform Encephalopathy (BSE), dioxin, foot and mouth disease and swine fever to name a few. Even though the first rules on food safety date from the very early days of the EU, a need was recognized to replace a number of these rules accumulated through the years, whose implementation was difficult to monitor, with a simpler and more comprehensive approach. The result w...

  5. Small Valdivia compact spaces

    CERN Document Server

    Kubi's, W; Kubi\\'s, Wieslaw; Michalewski, Henryk

    2005-01-01

    We prove a preservation theorem for the class of Valdivia compact spaces, which involves inverse sequences of ``simple'' retractions. Consequently, a compact space of weight $\\loe\\aleph_1$ is Valdivia compact iff it is the limit of an inverse sequence of metric compacta whose bonding maps are retractions. As a corollary, we show that the class of Valdivia compacta of weight at most $\\aleph_1$ is preserved both under retractions and under open 0-dimensional images. Finally, we characterize the class of all Valdivia compacta in the language of category theory, which implies that this class is preserved under all continuous weight preserving functors.

  6. Compact boson stars

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Betti [School of Engineering and Science, Jacobs University, Postfach 750 561, D-28725 Bremen (Germany); Kleihaus, Burkhard; Kunz, Jutta [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Schaffer, Isabell, E-mail: i.schaffer@jacobs-university.de [School of Engineering and Science, Jacobs University, Postfach 750 561, D-28725 Bremen (Germany)

    2012-07-24

    We consider compact boson stars that arise for a V-shaped scalar field potential. They represent a one parameter family of solutions of the scaled Einstein-Gordon equations. We analyze the physical properties of these solutions and determine their domain of existence. Along their physically relevant branch emerging from the compact Q-ball solution, their mass increases with increasing radius. Employing arguments from catastrophe theory we argue that this branch is stable, until the maximal value of the mass is reached. There the mass and size are on the order of magnitude of the Schwarzschild limit, and thus the spiraling respectively oscillating behaviour, well known for compact stars, sets in.

  7. Efeito da descompactação profunda de solo na produção da cultura da batata Effect of deep soil compaction alleviation on the production of potato crop

    Directory of Open Access Journals (Sweden)

    Carlos Francisco Ragassi

    2009-12-01

    .The soil tillage for potato in Brazil commonly relies on harrow utilization (shallow tillage, which causes a compacted zone below 20 cm. Apparently, deep soil loosening improves productivity and reduces tuber disease incidence and these effects can vary according to the species of grass cultivated before the potato crop. The objective of this work was to study deep loosening associated to the cultivation of Panicum maximum cv. Tanzânia, Brachiaria brizantha cv. Marandu and maize (Zea mays 'Dekalb 191' and the control (shallow tillage with the same maize genotype. The experiment was carried out in Piracicaba, São Paulo State, Brazil, from December 2006 to October 2008, in a complete randomized blocks design. The soil penetration resistance (SPR value, evaluated by impact penetrometer in the center of the seed bed, was lower than 1.5 MPa up to 40 cm depth for all treatments and, in the 40-60 cm layer, the SPR value in the shallow tillage (2.4 MPa was statistically higher than all other treatments, whose values ranged from 0.9 to 1.0 MPa. Tuber productivity in the shallow tillage was 28.3 t ha-1 and differed from the highest value among the deep soil loosening treatments (32.9 t ha-1. The proportion of tubers with less than 4 cm diameter in the shallow tillage (5.1% was higher than the deep soil alleviation treatments with maize (2.9% and B. brizantha (2.2%. The occurrence of tuber pests, diseases and lenticelose (Diabrotica speciosa, 31.0% to 49.7%; Streptomyces scabies, 3.3% to 6.3%; Helminthosporium solani, 60.3% to 69%; Rhizoctonia solani, 1.3% to 4.3%; lenticelose, 6.0% to 15.7%, was not influenced by the treatments. The deep soil loosening reduced soil penetration resistance and increased potato productivity, with lower rate of small tubers, but did not affect the occurrence of tuber pests, diseases and lenticelose.

  8. Roller compaction of theophylline

    OpenAIRE

    Hadzovic, Ervina

    2008-01-01

    1. Summary Direct compaction requires a very good flowability and compressibility of the materials. Those parameters become even more critical if the formulation contains large amount of active substance. To overcome these problems, several alternatives have been used. Roller compaction is a very attractive technology in the pharmaceutical industry. It is a fast and efficient way of producing granules, especially suitable for moisture sensitive materials. The intention of this work was to ...

  9. Application of dynamic compaction and rolling compaction in the subgrade improvement of Qarhan-Golmud Highway

    Institute of Scientific and Technical Information of China (English)

    Yu Zhang; JianKun Liu; JianHong Fang; AnHua Xu

    2013-01-01

    Melt shrinkage, salt bulge, and corrosiveness are common problems with saline soils, which damage highway foundations and cause huge financial losses. In order to improve the saline soil subgrade, dynamic compaction (DC) and rolling compaction (RC) technology were applied on the Qarhan-Golmud Highway in Qinghai Province, China. A field experi-ment was conducted in which shear strength, deformation modulus, and the working mechanism of the composite foun-dation were analyzed after reinforcement. Both the DC and RC methods were found to be effective and helped to improve the foundation strength of saline soils, although the ultimate bearing capacity and deformation modulus of the RC method were lower than that of the DC method.

  10. Soil compaction by machine traffic and least limiting water range related to soybean yield Compactação do solo por tráfego de máquinas e intervalo hídrico ótimo na produtividade de soja

    Directory of Open Access Journals (Sweden)

    Amauri Nelson Beutler

    2008-11-01

    Full Text Available The research aimed to evaluate machine traffic effect on soil compaction and the least limiting water range related to soybean cultivar yields, during two years, in a Haplustox soil. The six treatments were related to tractor (11 Mg weight passes by the same place: T0, no compaction; and T1*, 1; T1, 1; T2, 2; T4, 4 and T6, 6. In the treatment T1*, the compaction occurred when soil was dried, in 2003/2004, and with a 4 Mg tractor in 2004/2005. Soybean yield was evaluated in relation to soil compaction during two agricultural years in completely randomized design (compaction levels; however, in the second year, there was a factorial scheme (compaction levels, with and without irrigation, with four replicates represented by 9 m² plots. In the first year, soybean [Glycine max (L. Merr.] cultivar IAC Foscarim 31 was cultivated without irrigation; and in the second year, IAC Foscarim 31 and MG/BR 46 (Conquista cultivars were cultivated with and without irrigation. Machine traffic causes compaction and reduces soybean yield for soil penetration resistance between 1.64 to 2.35 MPa, and bulk density between 1.50 to 1.53 Mg m-3. Soil bulk density from which soybean cultivar yields decrease is lower than the critical one reached at least limiting water range (LLWR =/ 0.O estudo objetivou a avaliação do efeito do tráfego de máquinas sobre a compactação do solo, e a avaliação do intervalo hídrico ótimo e sua relação com a produtividade de cultivares de soja, durante dois anos, em Latossolo Vermelho. Os seis tratamentos foram relativos a passadas de trator (peso de 11 Mg pelo mesmo local: T0, sem compactação; T1*, 1; T1, 1; T2, 2; T4, 4 e T6, 6. No tratamento T1*, a compactação foi realizada quando o solo estava seco, em 2003/2004, e com um trator mais leve - de 4 Mg - em 2004/2005. No primeiro ano, a soja [Glycine max (L. Merr.] cultivar IAC Foscarim 31 foi cultivada sem irrigação e, no segundo ano, as cultivares IAC Foscarim 31 e MG/BR 46

  11. Use of digital images for evaluating soil compaction in the culture of beans Uso de imagens digitais para avaliação da compactação do solo na cultura do feijão

    Directory of Open Access Journals (Sweden)

    Daniel Mariano Leite

    2012-04-01

    Full Text Available Bean yield in Brazil is considered low, around 820 kg ha-1, reaching values above 3000 kg ha-1, there are several environmental factors which may limit the performance of this culture, especially those related to the soil. The present work aimed to evaluate soil compactions in bean culture of different soil management systems, by means of digital images. This study took place at the Federal University of Viçosa, randomized block design with six replications was used and four treatments, (direct planting, conventional preparation, minimum plantation using grade crusher-leveler and minimum plantation using scarificator, were evaluated. The spectral responses using the vegetation indexes (NDVI, RS, GNDVI, VARI, WDRVI and SAVI were evaluated, calculated from digital numbers of the images and the values were estimated from the reflectance. For obtainning the images, a platform containing two digital cameras, one sensitive in the region of visible (RGB and another sensitive to the region of proximal infrared were used, this platform was attached to a helium-inflatable balloon. The vegetation indexes obtained from the values of digital numbers of images were only able to defer treatments 70 days after plantation. However, indexes obtained from the reflectance, deferred treatments at 34 and 70 days after planting.A produtividade do feijoeiro no Brasil é considera baixa entorno de 820 kg ha-1, podendo atingir valores acima de 3.000 kg ha-1, vários fatores ambientais podem limitar o bom desempenho da cultura, principalmente os relacionados ao solo. Sendo assim objetivou-se com a realização deste trabalho avaliar a compactação do solo na cultura do feijoeiro em diferentes sistemas de manejo do solo, por meio de imagens digitais. Este trabalho foi realizado na Universidade Federal de Viçosa, utilizou-se o delineamento em blocos ao acaso com seis repetições, sendo quatros tratamentos avaliados (plantio direto, preparo convencional, cultivo m

  12. CONSIDERATIONS ON URBAN SOILS

    OpenAIRE

    Radu Lacatusu

    2005-01-01

    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...

  13. Improvement parameters in dynamic compaction adjacent to the slopes

    Directory of Open Access Journals (Sweden)

    Elham Ghanbari

    2015-04-01

    Full Text Available Dynamic compaction is a cost-effective method commonly used for improvement of sandy soils. A number of researchers have investigated experimentally and numerically the improvement parameters of soils using dynamic compaction, such as crater depth, improvement depth, and radial improvement, however, these parameters are not studied for improvement adjacent to the slopes or trenches. In this research, four different slopes with different inclinations are modeled numerically using the finite element code ABAQUS, and impact loads of dynamic compaction are applied. The static factors of safety are kept similar for all trenches and determined numerically by application of gravity loads to the slope using strength reduction method (SRM. The analysis focuses on crater depth and improvement region which are compared to the state of flat ground. It can be observed that compacted area adjacent to the slopes is narrower and slightly away from the slope compared to the flat state. Moreover, crater depth increases with increase in slope inclination.

  14. Improvement parameters in dynamic compaction adjacent to the slopes

    Institute of Scientific and Technical Information of China (English)

    Elham Ghanbari; Amir Hamidi

    2015-01-01

    Dynamic compaction is a cost-effective method commonly used for improvement of sandy soils. A number of researchers have investigated experimentally and numerically the improvement parameters of soils using dynamic compaction, such as crater depth, improvement depth, and radial improvement, however, these parameters are not studied for improvement adjacent to the slopes or trenches. In this research, four different slopes with different inclinations are modeled numerically using the finite element code ABAQUS, and impact loads of dynamic compaction are applied. The static factors of safety are kept similar for all trenches and determined numerically by application of gravity loads to the slope using strength reduction method (SRM). The analysis focuses on crater depth and improvement region which are compared to the state of flat ground. It can be observed that compacted area adjacent to the slopes is narrower and slightly away from the slope compared to the flat state. Moreover, crater depth increases with increase in slope inclination.

  15. Compactness theorems of fuzzy semantics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The relationship among diverse fuzzy semantics vs. the corresponding logic consequence operators has been analyzed systematically. The results that compactness and logical compactness of fuzzy semantics are equivalent to compactness and continuity of the logic consequence operator induced by the semantics respectively have been proved under certain conditions. A general compactness theorem of fuzzy semantics have been established which says that every fuzzy semantics defined on a free algebra with members corresponding to continuous functions is compact.

  16. Satellite altimeter remote sensing of ice caps

    OpenAIRE

    Rinne, Eero Juhani

    2011-01-01

    This thesis investigates the use of satellite altimetry techniques for measuring surface elevation changes of ice caps. Two satellite altimeters, Radar Altimeter 2 (RA-2) and Geoscience Laser Altimeter System (GLAS) are used to assess the surface elevation changes of three Arctic ice caps. This is the first time the RA-2 has been used to assess the elevation changes of ice caps - targets much smaller than the ice sheets which are the instrument’s primary land ice targets. Algor...

  17. 饱和软黏土中足尺静压桩挤土效应试验研究%Test research on soil compacting effect of full scale jacked-in pile in saturated soft clay

    Institute of Scientific and Technical Information of China (English)

    周火垚; 施建勇

    2009-01-01

    Soil compacting effect of jacked-in pile in the saturated soft clay is a topic of concern in the geotechnical engineering. Monitoring laws of lateral displacement of soil, pore pressure and land upheaval during pile-sinking is a project that a lot of researchers hope to implement. In this research, three full scale jacked-in piles are penetrated into the saturated soft clay and mostly studied by monitoring the law of lateral displacement with depth and radial distance to pile-sinking, the law of land upheaval with depth of penetration and radial distance to pile-sinking, and the law of pore pressure with penetration depth and time. Characteristics of maximum excess pore water pressure with radial distance and depth are also analyzed. From this test results, it is obtained that the maximum lateral displacement occurs at a depth of about 0.75L; land upheaval build up rapidly and reach the maximum when the pile tip arrive at depth of about 6 m; and the increment of excess pore water pressure reaches the maximum when the pile tip arrive at the piezometer level; while the maximum excess pore pressure presents a hysteresis quality with radial distance.%饱和软黏土地基中静压桩挤土效应是岩土工程中常见的问题.监测土体侧向位移、孔隙压力、地面隆起随压桩过程变化的规律是很多研究者希望实施的计划.在饱和软黏土地基中进行了3根足尺静压桩的压入试验,重点监测了沉桩时的侧向位移随深度和距桩轴不同距离、地面隆起量随桩的贯入深度和距桩轴不同距离、孔隙压力随桩的贯入深度和时间的变化规律,并分析了超静孔隙水压力最大值沿径向和深度的变化特性.由测试结果可知,最大的侧向位移发生在距地表0.75L附近,地面隆起从桩贯入开始迅速发展,并在桩压入到6 m左右时达到最大值,测点处超静孔压增量的最大值发生在桩端到达该点所在水平面时,而超孔压的最大值沿径向有滞后性.

  18. Compact Dynamical Foliations

    CERN Document Server

    Carrasco, Pablo D

    2011-01-01

    According to the work of Dennis Sullivan, there exists a smooth flow on the 5-sphere all of whose orbits are periodic although there is no uniform bound on their periods. The question addressed in this article is whether such an example can occur in the partially hyperbolic context. That is, does there exist a partially hyperbolic diffeomorphism of a compact manifold such that all the leaves of its center foliation are compact although there is no uniform bound for their volumes. We will show that the previous question has negative answer under very natural hypothesis as one-dimensional center foliation, transitivity or in the volume preserving case. Moreover we study the dynamical properties of partially hyperbolic maps preserving a compact center foliation. We prove in particular that if the number of center leaves with non-trivial holonomy is finite then the map is plaque expansive.

  19. Drosophila casein kinase I alpha regulates homolog pairing and genome organization by modulating condensin II subunit Cap-H2 levels.

    Directory of Open Access Journals (Sweden)

    Huy Q Nguyen

    Full Text Available The spatial organization of chromosomes within interphase nuclei is important for gene expression and epigenetic inheritance. Although the extent of physical interaction between chromosomes and their degree of compaction varies during development and between different cell-types, it is unclear how regulation of chromosome interactions and compaction relate to spatial organization of genomes. Drosophila is an excellent model system for studying chromosomal interactions including homolog pairing. Recent work has shown that condensin II governs both interphase chromosome compaction and homolog pairing and condensin II activity is controlled by the turnover of its regulatory subunit Cap-H2. Specifically, Cap-H2 is a target of the SCFSlimb E3 ubiquitin-ligase which down-regulates Cap-H2 in order to maintain homologous chromosome pairing, chromosome length and proper nuclear organization. Here, we identify Casein Kinase I alpha (CK1α as an additional negative-regulator of Cap-H2. CK1α-depletion stabilizes Cap-H2 protein and results in an accumulation of Cap-H2 on chromosomes. Similar to Slimb mutation, CK1α depletion in cultured cells, larval salivary gland, and nurse cells results in several condensin II-dependent phenotypes including dispersal of centromeres, interphase chromosome compaction, and chromosome unpairing. Moreover, CK1α loss-of-function mutations dominantly suppress condensin II mutant phenotypes in vivo. Thus, CK1α facilitates Cap-H2 destruction and modulates nuclear organization by attenuating chromatin localized Cap-H2 protein.

  20. Produção de capítulos florais da camomila em função de populações de plantas e da incorporação ao solo de cama-de-aviário Production of capitula of chamomile as a result of plant populations and chicken manure incorporated to the soil

    Directory of Open Access Journals (Sweden)

    Marisa B.M. Ramos

    2004-09-01

    Full Text Available O experimento foi realizado no horto de plantas medicinais da Universidade Federal de Mato Grosso do Sul, em Dourados, de abril a setembro/2000. Avaliou-se o efeito do uso de cama-de-aviário semidecomposta incorporada ao solo e populações de plantas sobre as características morfológicas, a produção e a qualidade do óleo essencial dos capítulos florais da camomila cv. 'Mandirituba'. Os fatores em estudo deram origem aos nove tratamentos, combinando respectivamente espaçamentos entre plantas (m e cama-de-aviário (kg m-2: 0,16 e 1,2; 0,24 e 1,2; 0,16 e 2,8; 0,24 e 2,8; 0,20 e 2,0; 0,11 e 1,2; 0,29 e 2,8; 0,16 e 0,2 e 0,24 e 3,8, dispostos no delineamento experimental de blocos casualizados, com quatro repetições. As características avaliadas foram altura de plantas; número, altura e diâmetro, massa fresca e seca e análise qualitativa do óleo essencial dos capítulos florais. A altura média máxima das plantas da camomila 'Mandirituba' foi de 0,61 m, sendo considerada cultivar de porte baixo. Não houve efeito significativo da interação espaçamentos entre plantas e cama-de-aviário sobre as características avaliadas. A produção dos capítulos florais foi influenciada mais intensamente pelo espaçamento entre plantas do que pela cama-de-aviário. O menor espaçamento induziu os maiores números (56,57 milhões ha-1 e massas secas dos capítulos florais (1.080 kg ha-1. As alturas (0,71 a 0,81 cm aos 100 dias e 0,68 a 0,71 cm aos 116 dias após transplante, o diâmetro (1,96 a 2,13 cm aos 100 dias e 1,83 a 1,91 cm aos 116 dias após transplante e a massa unitária dos capítulos florais (0,12 g não foram significativamente influenciados pelos tratamentos estudados. A produção média de massa seca dos capítulos florais (800 kg ha-1 foi maior que a média brasileira convencional (500 kg ha-1. O óleo essencial obtido, nas amostras dos nove tratamentos, apresentou cor azul intensa e odor característico, como descrito na

  1. Tachyons in Compact Spaces

    CERN Document Server

    Suyama, T

    2005-01-01

    We discuss condensations of closed string tachyons localized in compact spaces. Time evolution of an on-shell condensation is naturally related to the worldsheet RG flow. Some explicit tachyonic compactifications of Type II string theory is considered, and some of them are shown to decay into supersymmetric theories known as the little string theories.

  2. Nature mangement, landscape and the CAP

    NARCIS (Netherlands)

    Brouwer, F.M.; Godeschalk, F.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

  3. Microtubule dynamics: Caps, catastrophes, and coupled hydrolysis

    DEFF Research Database (Denmark)

    Flyvbjerg, H.; Holy, T.E.; Leibler, S.

    1996-01-01

    An effective theory is formulated for the dynamics of the guanosine triphosphate (GTP) cap believed to stabilize growing microtubules. The theory provides a ''coarse-grained'' description of the cap's dynamics. ''Microscopic'' details, such as the microtubule lattice structure and the fate of its...... data. A constant nonzero catastrophe rare, identical for both microtubule ends, is predicted at large growth rates. The delay time for dilution-induced catastrophes is stochastic with a simple distribution that fits the experimental one and, like the experimental one, does not depend on the rate of....... A recent experimental result for the size of the minimal cap that can stabilize a microtubule is shown to agree with the result predicted by the cap model, after its parameters have been extracted from previous experimental results. Thus the effective theory and cap model presented here provide a...

  4. Root responses to soil physical conditions; growth dynamics from field to cell.

    Science.gov (United States)

    Bengough, A Glyn; Bransby, M Fraser; Hans, Joachim; McKenna, Stephen J; Roberts, Tim J; Valentine, Tracy A

    2006-01-01

    Root growth in the field is often slowed by a combination of soil physical stresses, including mechanical impedance, water stress, and oxygen deficiency. The stresses operating may vary continually, depending on the location of the root in the soil profile, the prevailing soil water conditions, and the degree to which the soil has been compacted. The dynamics of root growth responses are considered in this paper, together with the cellular responses that underlie them. Certain root responses facilitate elongation in hard soil, for example, increased sloughing of border cells and exudation from the root cap decreases friction; and thickening of the root relieves stress in front of the root apex and decreases buckling. Whole root systems may also grow preferentially in loose versus dense soil, but this response depends on genotype and the spatial arrangement of loose and compact soil with respect to the main root axes. Decreased root elongation is often accompanied by a decrease in both cell flux and axial cell extension, and recent computer-based models are increasing our understanding of these processes. In the case of mechanical impedance, large changes in cell shape occur, giving rise to shorter fatter cells. There is still uncertainty about many aspects of this response, including the changes in cell walls that control axial versus radial extension, and the degree to which the epidermis, cortex, and stele control root elongation. Optical flow techniques enable tracking of root surfaces with time to yield estimates of two-dimensional velocity fields. It is demonstrated that these techniques can be applied successfully to time-lapse sequences of confocal microscope images of living roots, in order to determine velocity fields and strain rates of groups of cells. In combination with new molecular approaches this provides a promising way of investigating and modelling the mechanisms controlling growth perturbations in response to environmental stresses.

  5. Potential of conservation agriculture practices (CAPs) in enhancing food security of tribal people in central mid-hills of Nepal

    OpenAIRE

    Paudel, B.; T.J.K. Radovich; Halbrendt, Jacqueline; Thapa, K

    2012-01-01

    Traditional agriculture in central mid hills of Nepal is characterized by cultivation of steep sloping lands, resulting lower productivity, degradation of soil health and reduction of livelihood options. The Sustainable Management of Agro-ecological Resources in Tribal Societies (SMARTS) project applied a participatory agro-ecological framework to develop improved conservation practices (CAPs) to contribute to sustainable livelihood of Chepang tribal people in central Nepal. CAPs were identif...

  6. Do Differences in Chemical Composition of Stem and Cap of Amanita muscaria Fruiting Bodies Correlate with Topsoil Type?

    OpenAIRE

    Deja, Stanisław; Piotr P. Wieczorek; Halama, Marek; Jasicka-Misiak, Izabela; Kafarski, Paweł; Poliwoda, Anna; Młynarz, Piotr

    2014-01-01

    Fly agaric (Amanita muscaria) was investigated using a 1H NMR-based metabolomics approach. The caps and stems were studied separately, revealing different metabolic compositions. Additionally, multivariate data analyses of the fungal basidiomata and the type of soil were performed. Compared to the stems, A. muscaria caps exhibited higher concentrations of isoleucine, leucine, valine, alanine, aspartate, asparagine, threonine, lipids (mainly free fatty acids), choline, glycerophosphocholine (G...

  7. Hard Cap Espresso Machines in Analytical Chemistry: What Else?

    Science.gov (United States)

    Armenta, Sergio; de la Guardia, Miguel; Esteve-Turrillas, Francesc A

    2016-06-21

    A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under the employed chromatographic conditions; thus, those compounds were determined together. PAHs were extracted from 5.0 g of soil, previously homogenized, freeze-dried, and sieved to 250 μm, with 50 mL of 40% (v/v) acetonitrile in water at a temperature of 72 ± 3 °C. The proposed procedure is really fast, with an extraction time of 11 s, and it reduces the required amount of organic solvent to do the sample preparation. The obtained limit of detection for the evaluated PAHs was from 1 to 38 μg kg(-1). Recoveries were calculated using clean soils spiked with 100, 500, 1000, and 2000 μg kg(-1) PAHs with values ranging from 81 to 121% and good precision with relative standard deviation values lower than 30%. The method was validated using soil and sediment certified reference materials and also using real samples by comparison with ultrasound-assisted extraction, as reference methodology, obtaining statistically comparable results. Thus, the use of hard cap espresso machines in the analytical laboratories offers tremendous possibilities as low cost extraction units for the extraction of solid samples. PMID:27224000

  8. Hard Cap Espresso Machines in Analytical Chemistry: What Else?

    Science.gov (United States)

    Armenta, Sergio; de la Guardia, Miguel; Esteve-Turrillas, Francesc A

    2016-06-21

    A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under the employed chromatographic conditions; thus, those compounds were determined together. PAHs were extracted from 5.0 g of soil, previously homogenized, freeze-dried, and sieved to 250 μm, with 50 mL of 40% (v/v) acetonitrile in water at a temperature of 72 ± 3 °C. The proposed procedure is really fast, with an extraction time of 11 s, and it reduces the required amount of organic solvent to do the sample preparation. The obtained limit of detection for the evaluated PAHs was from 1 to 38 μg kg(-1). Recoveries were calculated using clean soils spiked with 100, 500, 1000, and 2000 μg kg(-1) PAHs with values ranging from 81 to 121% and good precision with relative standard deviation values lower than 30%. The method was validated using soil and sediment certified reference materials and also using real samples by comparison with ultrasound-assisted extraction, as reference methodology, obtaining statistically comparable results. Thus, the use of hard cap espresso machines in the analytical laboratories offers tremendous possibilities as low cost extraction units for the extraction of solid samples.

  9. Modeling the Effects of Cap and Trade and a Carbon Offset Policy on Crop Allocations and Farm Income

    OpenAIRE

    Nalley, Lawton Lanier; Popp, Michael P.

    2010-01-01

    A static, producer profit maximization framework is used to capture county level land use choice on the basis of profitability, greenhouse gas (GHG) emissions to the farm gate as well as soil carbon sequestration as affected by tillage and soil type. Policy scenarios of a 5% GHG cap on agricultural emissions in conjunction with a carbon offset payment system, designed to provide producer payments for net carbon footprint (GHG emissions – soil carbon sequestration) reductions compared to a bas...

  10. Compact fusion reactors

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Fusion research is currently to a large extent focused on tokamak (ITER) and inertial confinement (NIF) research. In addition to these large international or national efforts there are private companies performing fusion research using much smaller devices than ITER or NIF. The attempt to achieve fusion energy production through relatively small and compact devices compared to tokamaks decreases the costs and building time of the reactors and this has allowed some private companies to enter the field, like EMC2, General Fusion, Helion Energy, Lawrenceville Plasma Physics and Lockheed Martin. Some of these companies are trying to demonstrate net energy production within the next few years. If they are successful their next step is to attempt to commercialize their technology. In this presentation an overview of compact fusion reactor concepts is given.

  11. Compact torsatron reactors

    International Nuclear Information System (INIS)

    Low-aspect-ratio torsatron configurations could lead to compact stellarator reactors with R0 = 8--11m, roughly one-half to one-third the size of more conventional stellarator reactor designs. Minimum-size torsatron reactors are found using various assumptions. Their size is relatively insensitive to the choice of the conductor parameters and depends mostly on geometrical constraints. The smallest size is obtained by eliminating the tritium breeding blanket under the helical winding on the inboard side and by reducing the radial depth of the superconducting coil. Engineering design issues and reactor performance are examined for three examples to illustrate the feasibility of this approach for compact reactors and for a medium-size (R0 ≅ 4 m,/bar a/ /approx lt/ 1 m) copper-coil ignition experiment. 26 refs., 11 figs., 7 tabs

  12. Conservation agriculture & soil health: The US perspective

    OpenAIRE

    Idol, Travis

    2012-01-01

    The purpose of this presentation was to give a history and current status of soil conservation and conservation agriculture. It discusses soil quality indicators and gave recommendations for policies and practices, including adoption of conservation agriculture production systems that can help conserve soil and maintain agricultural productivity, especially on degraded farmland. LTRA-11 (CAPS among tribal societies in India and Nepal)

  13. Compactly Generated Domain Theory

    OpenAIRE

    Battenfeld, Ingo; Schröder, Matthias; Simpson, Alexander

    2006-01-01

    We propose compactly generated monotone convergence spaces as a well-behaved topological generalisation of directed-complete partial orders (dcpos). The category of such spaces enjoys the usual properties of categories of 'predomains' in denotational semantics. Moreover, such properties are retained if one restricts to spaces with a countable pseudobase in the sense of E. Michael, a fact that permits connections to be made with computability theory, realizability semantics and recent work on ...

  14. Energy report compact 2015

    International Nuclear Information System (INIS)

    The Energy Report compact 2015 from the Ministry of the Environment, Climate Protection and the Energy Sector and the State Office for Statistics Baden-Wuerttemberg provides an overview on the energy sector developments in Baden-Wuerttemberg in 2013. It contains numerous information on the energy consumption in Baden-Wuerttemberg, the energy productivity, the share of renewable energy sources, power generation and the energy-related CO2 emissions.

  15. Compact Quantum Groupoids

    OpenAIRE

    Landsman, N.P.

    1999-01-01

    Quantum groupoids are a joint generalization of groupoids and quantum groups. We propose a definition of a compact quantum groupoid that is based on the theory of C*-algebras and Hilbert bimodules. The essential point is that whenever one has a tensor product over the complex numbers in the theory of quantum groups, one now uses a certain tensor product over the base algebra of the quantum groupoid.

  16. Compact Torsatron configurations

    International Nuclear Information System (INIS)

    Low-aspect-ratio stellarator configurations can be realized by using torsatron winding. Plasmas with aspect ratios in the range of 3.5 to 5 can be confined by these Compact Torsatron configurations. Stable operation at high Β should be possible in these devices, if a vertical field coil system is adequately designed to avoid breaking of the magnetic surfaces at finite Β. 17 refs., 21 figs., 1 tab

  17. 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...

  18. CAPS and INMS Major Accomplishments

    Science.gov (United States)

    Waite, J. Hunter

    2014-05-01

    The Cassini-Huygens Ion Neutral Mass Spectrometer (Cassini INMS) and the Cassini Plasma Spectrometer (CAPS) have provided "discovery" science at Titan, Enceladus, Rhea/Dione, and throughout the magnetosphere of Saturn during the course of the mission. In this talk we will review some of the major scientific achievements: 1) the discovery of an extremely complex ion neutral organic chemistry in Titan's upper atmosphere that forms the building blocks for aerosol processes below, 2) the discovery of gases and grains emanating from Enceladus' cryo-geysers that tell us about chemical processes in an interior sea, 3) the first direct compositional measurements of sputtered icy moon surfaces, 4) the clearest example to date of the complex plasma interchange processes that occur in rapidly rotating magnetospheres of gas giants, initiating global dynamic processes that enable Saturn to shed the plasma from Enceladus' plume, and complete with a myriad of longitudinal and solar local-time variations, and 5) the dominance of Enceladus water outgassing as a source of magnetospheric plasma that stretches out to Titan and provides oxygen that can convert Titan's rich nitrile populations into amino acids.

  19. Compactação do solo e macronutrientes primários na Brachiaria brizantha cv. Piatã e Panicum maximum cv. Mombaça Soil compaction and primary macronutrients in Brachiaria brizantha cv. Piatã e Panicum maximum cv. Mombaça

    Directory of Open Access Journals (Sweden)

    Carlos E. A. Cabral

    2012-04-01

    Full Text Available Os macronutrientes primários possuem papel relevante na adubação de forrageiras, em função da sua participação no custo de produção, razão pela qual se objetivou avaliar os efeitos da compactação na concentração de macronutrientes primários em folhas diagnósticas dos capins Piatã e Mombaça. O experimento foi realizado em casa de vegetação, com delineamento inteiramente casualizado, composto de oito tratamentos e três repetições, em esquema fatorial 2x4, com duas gramíneas (capim-piatã e capim-mombaça e de quatro densidades do solo (1,0; 1,2; 1,4 e 1,6 Mg m-3. Dois cortes foram realizados, o primeiro aos 42 dias após o desbaste e o segundo 46 dias após o primeiro corte. No primeiro período de crescimento das gramíneas forrageiras a compactação do solo interfere na absorção de nitrogênio e fósforo enquanto no segundo período de crescimento ocorre limitação na absorção de nitrogênio e potássio. O nitrogênio é o macronutriente primário mais limitado pela compactação do solo.The primary macronutrients have an important role in the forage fertilization, depending on their contribution to the production cost. This paper aimed to evaluate the effects of soil compaction on the concentration of primary macronutrients present in diagnostic leaves of Piatã and Mombaça grasses. The experiment was conducted in a greenhouse with a randomized statistical design, consisting of eight treatments and three replications in 2 x 4, factorial scheme, with two grases (Piatã grass and Mombaça and four soil densities (1.0, 1.2 , 1.4 and 1.6 Mg m-3. Two harvest of shoots were made, the first 42 days after the plant thinning, and the second 46 days after the first cutting. In the first growing period, the soil compaction interfere with the absorption of nitrogen and phosphorus, while in the second growing period there is a limitation in the absorption of nitrogen and potassium. Nitrogen is the primary macronutrient most

  20. Chemical features of soils in a natural forest of West Hungary

    Science.gov (United States)

    Hofmann, Eszter; Bidló, András

    2015-04-01

    The present research focuses on the chemical results of soils formed on miocene carbonate rocks in a natural forest of West Hungary. Soil profiles derived from the Szárhalom Forest, located near the Lake Fertő, next to the city of Sopron. Six soil profiles were opened and analysed in this area. In the field the following physical parameters were evaluated from the soil profiles: transition, structure, compactness, roots, skeletal percent, colour, physical assortment, concretion and soil defect. Laboratory analysis involved the measurement of acidity, particle distribution, carbonated lime content, humus content, ammonium lactate-acetic acid soluble phosphorus- and potassium content, potassium chloride soluble calcium- and magnesium content, ethylene-diamine-tetraacetic-acid (EDTA) and diethylene-triamine-pentaacetic-acid (DTPA) soluble copper-, iron-, manganese- and zinc contents. These soils formed under a hornbeam-oak forest climate mainly and under a beech forest climate diffusely. The location and climate of the sites forms a basis of the comparison of the soils with similar base rock. The formation of the acidic and humus-rich upper layer of the soil profiles is influenced by the mineral composition and the weathering of the rocks. X-ray diffraction (Philips P W3710/PW1050 type X-ray diffractometer), thermoanalytical measurements (Mettler Toledo TGA/DSC 1 type thermogravimeter) and ICP-OES (Thermo Scientific iCAP 7000 Series) were also carried out to determine the mineral composition of the soils and the content of heavy metals. The soil samples were collected with both traditional and undisturbed (using the Kubiena box) sampling methods to enable further micromorphological investigations as well. The research is supported by the "Agroclimate-2" (VKSZ_12-1-2013-0034) joint EU-national research project. Key words: Natural forest, Miocene limestone, Mineral composition, Thermal analysis, Micromorphology

  1. Vertical Dynamic Impedance of Tapered Pile considering Compacting Effect

    Directory of Open Access Journals (Sweden)

    Wenbing Wu

    2013-01-01

    Full Text Available Based on complex stiffness transfer model, the vertical vibration of tapered pile embedded in layered soil is theoretically investigated by considering the compacting effect of the soil layer surrounding the tapered pile in the piling process. Allowing for the stratification of the surrounding soil and variable crosssection of the tapered pile, the pile-soil system is discretized into finite segments. By virtue of the complex stiffness transfer model to simulate the compacting effect, the complex stiffness of different soil segments surrounding the tapered pile is obtained. Then, substituting the complex stiffness into the vertical dynamic governing equation of tapered pile, the analytical solution of vertical dynamic impedance of tapered pile under vertical exciting force is derived by means of the Laplace technique and impedance function transfer method. Based on the presented solutions, the influence of compacting effect of surrounding soil on vertical dynamic impedance at the pile head is investigated within the low frequency range concerned in the design of dynamic foundation.

  2. 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.

  3. Capping stack: An industry in the making

    Institute of Scientific and Technical Information of China (English)

    Jack Chen; Li Xunke; Xie Wenhui; Kang Yongtian

    2013-01-01

    This paper gives an overview of recent development of the marine well containment system (MWCS)after BP Macondo subsea well blowout occurred on April 20,2010 in the Gulf of Mexico.Capping stack,a hardware utilized to contain blowout well at or near the wellhead is the center piece of MWCS.Accessibility to the dedicated capping stacks is gradually becoming a pre-requirement to obtain the permit for offshore drilling/workover,and the industry for manufacturing,maintenance,transportation and operation of the capping stack is in the making.

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

    International Nuclear Information System (INIS)

    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

  5. 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)

    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

  6. A study on the thermal conductivity of compacted bentonites

    CERN Document Server

    Tang, Anh-Minh; Le, Trung Tinh; 10.1016/j.clay.2007.11.001

    2008-01-01

    Thermal conductivity of compacted bentonite is one of the most important properties in the design of high-level radioactive waste repositories where this material is proposed for use as a buffer. In the work described here, a thermal probe based on the hot wire method was used to measure the thermal conductivity of compacted bentonite specimens. The experimental results were analyzed to observe the effects of various factors (i.e. dry density, water content, hysteresis, degree of saturation and volumetric fraction of soil constituents) on the thermal conductivity. A linear correlation was proposed to predict the thermal conductivity of compacted bentonite based on experimentally observed relationship between the volumetric fraction of air and the thermal conductivity. The relevance of this correlation was finally analyzed together with others existing methods using experimental data on several compacted bentonites.

  7. Estabilização química do subleito de estradas: influência do tempo decorrido entre a mistura e a compactação na resistência mecânica de misturas solo-RBI Grade 81 Chemical stabilization of road subgrade: influence of elapsed time between mixture and compaction on mechanical strength of soil-RBI Grade 81 mixtures

    Directory of Open Access Journals (Sweden)

    Tiago Pinto da Trindade

    2005-06-01

    Full Text Available Este artigo aborda o estudo da influência do tempo decorrido entre mistura e compactação na resistência mecânica de três solos da Zona da Mata Norte de Minas Gerais, Brasil, quando estabilizados com 4% de RBI Grade 81, em relação ao peso de solo seco. Um solo residual maduro (solo 1 e dois solos residuais jovens (solos 2 e 3 de gnáisse foram utilizados no presente estudo. O programa de ensaios de laboratório englobou: (i tempos decorridos entre mistura e compactação: 0, 4, 8 e 24 horas; (ii energia de compactação: Proctor Modificado; (iii período de cura das misturas: 7 dias; e (iv determinação da resistência mecânica: média de três determinações da resistência à compressão não-confinada. Os resultados desta pesquisa indicam que: (i o tempo decorrido entre mistura e compactação dos corpos-de-prova influenciou significativamente o parâmetro resistência à compressão não confinada das misturas; (ii 4 horas foi o tempo ótimo entre mistura e compactação para as misturas dos solos 1 e 2 com RBI Grade 81; e (iii no solo 3, foi observado um melhor resultado para a compactação imediatamente após a mistura.This paper describes the study of the influence of time between mixture and compaction in the mechanical strength of three soils from ";Zona da Mata Norte";, Minas Gerais, Brazil, stabilized with 4% of RBI Grade 81. One mature (soil 1 and two young (soils 2 and 3 gneiss residual soils were used throughout the study. The laboratory testing program consisted of the following steps: (i elapsed times between mixture and compaction: 0, 4, 8 and 24 hours; (ii mixture specimen compaction effort: Modified Proctor; (iii mixture specimen curing time: 7 days in acclimatized room; (iv determination of mechanical strength: average of three determinations of unconfined compression strength. The testing data supported that: (i the elapsed time between mixture and specimen compaction affected significantly the mixture mechanical

  8. Compactação do solo: efeitos nas características produtivas e morfológicas dos capins Piatã e Mombaça Soil compaction: effects on morphological and productive characteristics of Piatã and Mombaça grasses

    Directory of Open Access Journals (Sweden)

    Emerson A. Bonelli

    2011-03-01

    Full Text Available As gramíneas dos gêneros Panicum e Brachiaria, possuem participação expressiva nas pastagens da região do Cerrado, mas poucos trabalhos se referem aos seus comportamentos em condição de compactação do solo. Objetivou-se, então, avaliar o desenvolvimento das gramíneas forrageiras Brachiaria brizantha cv. Piatã e Panicum maximum cv. Mombaça sob níveis de compactação do solo. O experimento foi conduzido em casa de vegetação da Universidade Federal de Mato Grosso. O delineamento experimental utilizado foi inteiramente casualizado, com oito tratamentos e três repetições, arranjados em esquema fatorial que envolveu duas gramíneas forrageiras e quatro níveis de compactação, 1,0; 1,2; 1,4 e 1,6 Mg m-3. Foram realizados dois cortes e as variáveis avaliadas foram: número de perfilhos (NP, massa seca da lâmina foliar (MSF, massa seca de colmo (MSC, massa seca de raiz (MSR, relação folha/colmo (MSF/MSC; massa seca da parte aérea (MSPA e relação MSPA/MSR. Os níveis de compactação do solo não influenciaram a produção do capim-piatã nos dois crescimentos da gramínea. O capim-mombaça apresentou redução na produção nos níveis de compactação do solo, no segundo crescimento.The grasses of the genera Brachiaria and Panicum have significant participation in the grasslands of the Cerrado region, but few studies relate their behavior in conditions of soil compaction. The objective was to evaluate the development of grasses Brachiaria brizantha v. Piatã and Panicum maximum v. Mombaça in increasing levels of soil compaction. The experiment was carried out in a greenhouse at Federal University of Mato Grosso. The experimental design was completely randomized with 8 treatments and 3 replications, arranged in a factorial design involving two grasses and four compaction levels, 1.0, 1.2, 1.4 and 1.6 Mg m-3. Two cultings were made and the evaluated variables were: number of tillers NT, dry matter of leaf blade (DMLB, dry

  9. Circumpolar Active-Layer Permafrost System (CAPS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Circumpolar Active-Layer Permafrost System (CAPS) contains over 100 data sets pertaining to permafrost and frozen ground topics. It also contains detailed...

  10. C-CAP Land Cover, Niihau, Hawaii

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change Analysis Program (C-CAP) protocol to determine...

  11. C-CAP Land Cover, Molokai, Hawaii

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change Analysis Program (C-CAP) protocol to determine...

  12. C-CAP Land Cover, Lanai, Hawaii

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change Analysis Program (C-CAP) protocol to determine...

  13. Mapping of p140Cap phosphorylation sites

    DEFF Research Database (Denmark)

    Repetto, Daniele; Aramu, Simona; Boeri Erba, Elisabetta;

    2013-01-01

    protein, in which both EPLYA/EGLYA tyrosines were converted to phenylalanine, was no longer tyrosine phosphorylated, despite the presence of other tyrosine residues in p140Cap sequence. Moreover, this mutant lost its ability to bind the C-terminal Src kinase (Csk), previously shown to interact with p140...... phosphorylation and tunes its interactions with other regulatory molecules via post-translation modification. In this work, using mass spectrometry, we found that p140Cap is in vivo phosphorylated on tyrosine (Y) within the peptide GEGLpYADPYGLLHEGR (from now on referred to as EGLYA) as well as on three serine...... residues. Consistently, EGLYA has the highest score of in silico prediction of p140Cap phosphorylation. To further investigate the p140Cap function, we performed site specific mutagenesis on tyrosines inserted in EGLYA and EPLYA, a second sequence with the same highest score of phosphorylation. The mutant...

  14. C-CAP Hawaii 2005 Land Cover

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change Analysis Program (C-CAP) protocol to determine...

  15. C-CAP Land Cover, Maui, Hawaii

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change Analysis Program (C-CAP) protocol to determine...

  16. 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.

  17. 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. PMID:27337437

  18. 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.

  19. Design and implementation of the CAPS receiver

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, based on analyses of the Chinese Area Positioning System (CAPS) satellite (GEO satellite) resources and signal properties, the signal power at the port of the receiver antenna is estimated, and the implementation projects are presented for a switching band C to band L CAPS C/A code receiver integrated with GPS receiver suite and for a CAPS dual frequency P code receiver. A microstrip receiving antenna is designed with high sensitivity and wide beam orientation, the RF front end of the C/A code and P code receivers, and a processor is designed for the navigation baseband. A single frequency CAPS C/A code receiver and a CAPS dual frequency P code receiver are built at the same time. A software process flow is provided, and research on relatively key techniques is also conducted, such as signal searching, code loop and carrier loop algorithms, a height assistant algorithm, a dual frequency difference speed measurement technique, a speed measurement technique using a single frequency source with frequency assistance, and a CAPS time correcting algorithm, according to the design frame of the receiver hardware. Research results show that the static plane positioning accuracy of the CAPS C/A code receiver is 20.5-24.6 m, height accuracy is 1.2-12.8 m, speed measurement accuracy is 0.13-0.3 m/s, dynamic plane positioning accuracy is 24.4 m, height accuracy is 3.0 m, and speed measurement accuracy is 0.24 m/s. In the case of C/A code, the timing accuracy is 200 ns, and it is also shown that the positioning accuracy of the CAPS precise code receiver (1σ ) is 5 m from south to north, and 0.8 m from east to west. Finally, research on positioning accuracy is also conducted.

  20. UNDERSTANDING FARMERS’ RESPONSES TO CAP REFORM

    OpenAIRE

    Menozzi, Davide; Fioravanzi, Martina; Donati, Michele

    2014-01-01

    The 2014-2020 Common Agricultural Policy (CAP) reform defines new rules for farmers including regionalization, crop diversification and ecological focus area (EFA). This paper aims to evaluate farmers’ intention to modify their behaviour because of the CAP reform, using the Theory of Planned Behaviour (TPB). A questionnaire was submitted to 71 Italian durum wheat producers assessing their intention to change durum wheat surface and to maintain as EFA part of the arable land. Subjective norms ...

  1. Compact Q-balls

    CERN Document Server

    Bazeia, D; Marques, M A; Menezes, R; da Rocha, R

    2016-01-01

    In this work we deal with non-topological solutions of the Q-ball type in two space-time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

  2. Compact synchrotron light sources

    CERN Document Server

    Weihreter, Ernst

    1996-01-01

    This book covers a new niche in circular accelerator design, motivated by the promising industrial prospects of recent micromanufacturing methods - X-ray lithography, synchrotron radiation-based micromachining and microanalysis techniques. It describes the basic concepts and the essential challenges for the development of compact synchrotron radiation sources from an accelerator designer's point of view and gives an outline of the actual state of the art. The volume is intended as an introduction and as a reference for physicists, engineers and managers involved in this rapidly developing fiel

  3. Compact LINAC for deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S S [Los Alamos National Laboratory; O' Hara, J F [Los Alamos National Laboratory; Rybarcyk, L J [Los Alamos National Laboratory

    2008-01-01

    We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

  4. Research on mechanical vibration compaction method treatment of coastal large area reclamation sandy soil%机械振密法处理沿海大面积吹填砂性土研究

    Institute of Scientific and Technical Information of China (English)

    郑乾; 王春; 高向阳

    2014-01-01

    结合工程实例,对机械振密法施工工艺做了介绍,同时利用浅层平板载荷试验和原位试验对机械振密法的加固效果进行了研究分析,得出了该方法可以明显提升地基承载力的结论,并综合比较了机械振密法在各个方面相比其他传统方法的优越性,突出了该方法的实用、性价比高的特点。%Combining with the engineering examples introduced the construction technology of mechanical vibration compaction method,using the shallow plate loading test and in-situ test researched and analyzed the reinforcement effect of mechanical vibration compaction method,gained the conclusion of the method could obviously improve the foundation bearing capacity,and comprehensive compared the superiority of mechanical vibration compaction method compared to other traditional methods in all aspects,highlighted the characteristics of this method using high per-formance price ratio.

  5. Field Performance of a Winged Scarifier as a Function of Soil Compaction and Water Content Desempeño a Campo de un Escarificador Alado en Función de la Compactación y el Contenido de Agua del Suelo

    Directory of Open Access Journals (Sweden)

    Carmen Cholaky

    2010-03-01

    Full Text Available Initial soil conditions, operational aspects, and tool shape affect the efficiency of soil decompaction. The objective of this study was to evaluate the performance of a winged scarifier as a function of soil compaction and edaphic water content. The experiment was carried out in a typical Hapludoll. Treatments considered two soil compaction levels: high (HC and low compaction (LC; and three soil water contents: wet (WS, humid (HS, and dry (DS with 9, 14, and 19% gravimetric water content, respectively. A split-plot randomized block design was applied. Tractive effort, disturbed area, tillage depth, specific resistance, and power were evaluated. Results showed that tractive effort was 17% greater in HC than LC, and in both cases HS was greater than WS and DS. The specific resistance in HC was equal to 8, 9, and 11 N cm-2 in WS, HS, and DS, respectively, and 7, 8, and 7 N cm-2 in BC in similar soil water contents, respectively. Tillage depth was low and irregular only in HC-DS. Specific resistance was not an adequate indicator of overall work efficiency because it does not consider the final soil physical profile. Overall work efficiency in HC was greater under HS conditions, while in LC it was greater under HS and DS conditions.El estado inicial del suelo, aspectos operativos y de diseño de las herramientas, influyen sobre la eficiencia de una labor de descompactación. El objetivo de este trabajo fue evaluar el desempeño de un escarificador alado en función de la compactación y humedad edáfica. La experiencia se realizó en un Hapludol típico. Los tratamientos abarcaron dos niveles de compactación: alta (HC y baja (LC y tres contenidos de agua del suelo, mojado (WS, húmedo (HS y seco (DS, con 9; 14 y 19% de humedad, respectivamente. El diseño experimental fue en parcelas subdivididas en bloques al azar. Se evaluó esfuerzo de tracción, área disturbada, profundidad de trabajo, resistencia específica y potencia. Los resultados

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

    CERN Document Server

    Brown, Adrian J; 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 s...

  7. 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.

  8. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion

    OpenAIRE

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The “open field” soil gas vapor concentration profile is observed to be sensitive to the soil moisture di...

  9. INFLUENCE OF SOIL STRUCTURE ON CONFINED COMPRESSION BEHAVIOUR OF COMPACTED LOESS%结构性对压实黄土侧限压缩特性的影响

    Institute of Scientific and Technical Information of China (English)

    陈存礼; 蒋雪; 杨炯; 张洁; 薛军秀

    2014-01-01

    A series of confined compression tests were performed on compacted loess samples of different structures(fabrics) with the same dry density and initial testing water content. The influence of structure caused by different molding water contents on the compressive properties was analyzed for compacted loess with different initial testing water contents. The relationships between the compressibility indices and the initial structural parameter were investigated. The compression curve of saturated compacted loess was regarded as the reference state. The formula of compression curve of unsaturated compacted loess was established to determine the compressive deformation under the coupling of moisture and stress. The test results show that the molding water content has certain influence on the confining compression characteristic of compacted loess,and the extent of the influence decreases with the increase of initial testing water content. The structural influence on compressive deformation of saturated compacted loess is little. The initial structure index of compacted loess increases with increasing of molding water content or decreasing of initial testing water content. The structural change has little influence on the elastic compression indices,but both the structural yield stress and compression indices increase with the increase of initial structural parameter. The relationships of the structural yield stress and the compression indices with the initial structural parameter are normalized well and can be described with hyperbola under different initial testing water contents and molding water contents.%对一定试验含水率及干密度下具有不同结构性(排列)的压实黄土试样进行侧限压缩试验,分析制样含水率引起的结构性变化对不同试验含水率压实黄土侧限压缩特性的影响,探讨压缩性指标与初始结构性参数之间的关系。以饱和压实黄土的压缩曲线为基础,通过引入反映结构性

  10. A compact SADM family

    Science.gov (United States)

    Barbet, Vincent; Le Quintrec, Cyrille; Jeandot, Xavier; Chaix, Alain; Grain, Eric; Roux, Jerome

    2005-07-01

    Alcatel Space has developed a new SADM family driven by cost, modularity, mass and performances. The modularity concept is based on separating the rotation drive function from the electrical transfer function. The drive actuator has been designed for various applications where pointing and reliability is needed. It can be associated with high dissipative rotary devices (SA collectors, RF joints..). The design goal was to minimize the number of parts in order to reach the most simple and compact mechanism. Mass reduction was achieved by reducing as much as possible the load path between the Solar Array interface and the spacecraft interface. Following these guidelines, the drive actuator was developed and qualified on ATV SADM (part od Alcatel Space Solar Array Drive Sub System for ATV). Further more a high power integrated collector was qualified inside the SADM for Geo-stationary telecom satellite (SPACEBUS platforms). Fine thermal and mechanical modeling was necessary to predict SADM behaviors for the numerous thermal environments over the missions (steady and transient cases). These modeling were well correlated through mechanical and thermal balances qualification tests. The challenging approach of thermal dissipation in a compact design leads to a family of 3 SADM capabilities form 2kW up to 15kW per SADM weighing less than 4.5 kg each.

  11. Capping complex formation at the slow-growing end of the actin filament.

    Science.gov (United States)

    Kostyukova, A S

    2008-12-01

    Actin filaments are polar; their barbed (fast-growing) and pointed (slow-growing) ends differ in structure and dynamic properties. The slow-growing end is regulated by tropomodulins, a family of capping proteins that require tropomyosins for optimal function. There are four tropomodulin isoforms; their distributions vary depending on tissue type and change during development. The C-terminal half of tropomodulin contains one compact domain represented by alternating alpha-helices and beta-structures. The tropomyosin-independent actin-capping site is located at the C-terminus. The N-terminal half has no regular structure; however, it contains a tropomyosin-dependent actin-capping site and two tropomyosin-binding sites. One tropomodulin molecule can bind two tropomyosin molecules. Effectiveness of tropomodulin binding to tropomyosin depends on the tropomyosin isoform. Regulation of tropomodulin binding at the pointed end as well as capping effectiveness in the presence of specific tropomyosins may affect formation of local cytoskeleton and dynamics of actin filaments in cells. PMID:19216712

  12. Diferentes graus de compactação e fornecimento de fósforo influenciando no crescimento de plantas de milho (Zea mays L. cultivadas em solos distintos Different compaction degrees and phosphorus supply influencing the corn plants growth (Zea mays L. cultivated in different soils

    Directory of Open Access Journals (Sweden)

    Gislene Aparecida dos Santos

    2005-08-01

    Full Text Available O crescimento e desenvolvimento das plantas podem ser limitados por impedimentos físicos e químicos que impedem o desenvolvimento radicular e restringe a absorção de nutrientes. Com a finalidade de avaliar o efeito de diferentes graus de compactação e doses de fósforo, na produção de matéria seca, teores de fósforo e fósforo acumulado na parte aérea do milho (Zea mays L., um experimento foi conduzido em casa-de-vegetação, usando três solos, sendo um mais argiloso, Latossolo Vermelho Distrófico típico (LVd, um com textura média, Latossolo Vermelho-Amarelo Distrófico (LVAd e um com textura arenosa, Neossolo Quartzarênico (RQ. Na montagem dos vasos, foi feita a calagem com calcário dolomítico e a adubação básica, sendo os graus de compactação obtidos mediante o ensaio de Proctor Normal. As maiores produções de MSPA, TPPA e PAPA foram obtidas nos graus de compactação 65 e 75% e na maior dose de fósforo aplicada. Em um mesmo grau de compactação a maior produção de matéria seca da parte aérea (MSPA, os maiores teores de fósforo (TPPA e os maiores teores de fósforo acumulado na parte aérea (PAPA, ocorreram na maior dose de fósforo aplicado. O fósforo aplicado funcionou como um fator de aliviamento da compactação do solo, resultando em uma maior produção para um mesmo grau de compactação.The growth and development of the plants can be limited by physical and chemical impediments that limit roots development and restricts nutrients absorption. With the purpose of evaluating the effect of different degrees of compaction and phosphorus doses, in the production of dry matter, level of phosphorus and accumulated phosphorus in the aerial part of the corn (Zea mays L., an experiment was set up in a green house conditions, using three soils, being a clay one, distrofic Red Latosol, one with loamy texture, distrofic Red Yellow Latosol and one with sandy texture, Quartzarenic Neosol. In the assembly of the vases

  13. 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.

  14. SOMBRERO, BEARSKIN1, and BEARSKIN2 regulate root cap maturation in Arabidopsis.

    Science.gov (United States)

    Bennett, Tom; van den Toorn, Albert; Sanchez-Perez, Gabino F; Campilho, Ana; Willemsen, Viola; Snel, Berend; Scheres, Ben

    2010-03-01

    The root cap has a central role in root growth, determining the growth trajectory and facilitating penetration into the soil. Root cap cells have specialized functions and morphologies, and border cells are released into the rhizosphere by specific cell wall modifications. Here, we demonstrate that the cellular maturation of root cap is redundantly regulated by three genes, SOMBRERO (SMB), BEARSKIN1 (BRN1), and BRN2, which are members of the Class IIB NAC transcription factor family, together with the VASCULAR NAC DOMAIN (VND) and NAC SECONDARY WALL THICKENING PROMOTING FACTOR (NST) genes that regulate secondary cell wall synthesis in specialized cell types. Lateral cap cells in smb-3 mutants continue to divide and fail to detach from the root, phenotypes that are independent of FEZ upregulation in smb-3. In brn1-1 brn2-1 double mutants, columella cells fail to detach, while in triple mutants, cells fail to mature in all parts of the cap. This complex genetic redundancy involves differences in expression, protein activity, and target specificity. All three genes have very similar overexpression phenotypes to the VND/NST genes, indicating that members of this family are largely functionally equivalent. Our results suggest that Class IIB NAC proteins regulate cell maturation in cells that undergo terminal differentiation with strong cell wall modifications.

  15. 75 FR 49527 - Caps Visual Communications, LLC; Black Dot Group; Formerly Known as Caps Group Acquisition, LLC...

    Science.gov (United States)

    2010-08-13

    ... Employment and Training Administration Caps Visual Communications, LLC; Black Dot Group; Formerly Known as... Adjustment Assistance on June 24, 2010, applicable to workers of Caps Visual Communications, LLC, Black Dot..., Caps Visual Communications, LLC, Black Dot Group, formerly known as Caps Group Acquisition,...

  16. 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.

  17. Scenarios for a cap beyond 2013; Implications for EU27 agriculture and the cap budget

    NARCIS (Netherlands)

    Helming, J.F.M.; Terluin, I.J.

    2011-01-01

    An ex ante analysis of a set of five policy components (proposed post 2013 CAP measures) has been carried out for the 2014-2020 period, based on the EC Communication The CAP towards 2020 of 18 November 2010. The policy components are defined in such a way that they focus on the contribution of farme

  18. Compact SPS - Power delivery

    Science.gov (United States)

    Pospisil, M.; Pospisilova, L.

    1982-09-01

    The power deliverable by a compact solar Space Power Station (SPS) is a function of its outer surface shape. Methods of fitting the power delivery curve of such a system to different patterns of daily power demand are considered that involve the appropriate choice of the number of satellites, their maximal power, height to width ratio and the shift of longitude with respect to the receiving station. Changes in the daily delivery curve can be made by altering the longitudes and orientations of the satellites. Certain limitations to the choice of parameters exist, such as: the height to width ratio should be near 1.2, and the sum of longitude and orientation changes will probably not be greater than 50 deg. The optimization of the peak to average power ratio is also discussed.

  19. Compact semiconductor lasers

    CERN Document Server

    Yu, Siyuan; Lourtioz, Jean-Michel

    2014-01-01

    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  20. Compact cryocooler heat exchangers

    International Nuclear Information System (INIS)

    Compact heat exchangers are subject to different constraints as a room temperature gas is cooled down by a cold stream returning from a JT valve (or a similar cryoprocess component). In particular, the optimization of exchangers for liquid helium systems has to cover a wide range in temperature and density of the fluid. In the present work we address the following thermodynamic questions: 1. The optimization of intermediate temperatures which optimize stage operation (a stage is assumed to have a constant cross section); 2. The optimum temperature difference available for best overall economic performance values. The results are viewed in the context of porous media concepts applied to rather low speeds of fluid flow in narrow passages. In this paper examples of fluid/solid constraints imposed in this non-classical low temperature area are presented

  1. Optimizing reed canary grass cropping to increase profitability. Field studies of plant varieties, intercropping with legumes and barley, fertilization and soil compaction; Optimering av odlingsaatgaerder i roerflen foer oekad loensamhet. Faeltstudier av sorter, samodling med baljvaexter och korn, goedsling samt markpackning

    Energy Technology Data Exchange (ETDEWEB)

    Palmborg, Cecilia; Lindvall, Eva (Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Agricultural Research for Northern Sweden)

    2010-05-15

    Reed Canary Grass is a promising crop for biofuel production. For reed canary grass the first year is an establishment year when the small biomass is not harvested. The second year the biomass is usually cut in late autumn but the harvest (removal of the biomass from the field) is delayed until spring. This technique has resulted in lower costs and increases in fuel quality through lower ash contents, including lower contents of chlorine, sodium and potassium. However costs for production are still high, especially establishment costs, fertilization costs and harvesting costs. The aim of this project was to test ways to cut costs per MWh by increased yields, and decreased establishment costs. The methods used have been variety trials to develop more productive plant material, intercropping with nitrogen fixing legumes to reduce the nitrogen demand of the crop, fertilization with waste material (sewage sludge, reed canary grass ash or poultry manure) and harvest at frozen ground as a strategy to reduce soil compaction and harvest damages on the crop. Reed canary grass grown as a fuel has so far been grown as a mono culture. However, when it is been grown for forage, or as a biogas crop, intercropping with legumes has been successful in some studies. In addition to NPK-fertilizers sewage sludge, ash from combustion of reed canary grass and poultry manure was used. An economic calculation showed that the establishment costs (the first two growing seasons) can be lowered by intercropping with red clover. However it is also involves more risks, related to weeds, and cannot be recommended on fallow soil with a large seed bank of weeds. A ten year old reed canary grass ley was used for the experiment. Two 25 m wide strips were harvested with a mower on November 19 2008 when the top soil was frozen. The harvested material was chopped and removed from the field the following day. The following spring, May 19 2009, the remaining reed canary grass on the field was cut with a

  2. Analysis on the positioning precision of CAPS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    As a newly developed satellite positioning system, the Chinese Area Positioning System (CAPS) is a typical direct sequence spread spectrum ranging system like GPS. The positioning precision of such navigation signals depends on many factors, including the pseudo-code rate, the signal to noise ratio, the processing methods for tracking loops and so on. This paper describes the CAPS link budget, the solution approach for CAPS positioning, focusing on the autocorrelation function feature of C/A code signals. The CAPS signal measurement precision is studied by the software approach together with theoretical analysis of the range resolution. Because the conventional Delay Lock Loop (DLL) is vul- nerable to the impact of noise, a narrow correlator and multiple correlators as well as the corresponding discrimination methods of phases are proposed, which improves the robustness of DLL and the code-phase resolution of the measurement. The results show that the improvement of the DLL structure and the discrimination method are the most important way to improve the ranging resolution. Theoretical analysis and experimental results show that a CAPS receiver could reach a 20-m positioning precision by using three satellites with a supported height from an altimeter.

  3. Analysis on the positioning precision of CAPS

    Institute of Scientific and Technical Information of China (English)

    JI YuanFa; SUN XiYan

    2009-01-01

    As a newly developed satellite positioning system,the Chinese Area Positioning System (CAPS) Is a typical direct sequence spread spectrum ranging system like GPS.The positioning precision of such navigation signals depends on many factors,including the pseudo-code rate,the signal to noise ratio,the processing methods for tracking loops and so on.This paper describes the CAPS link budget,the solution approach for CAPS positioning,focusing on the autocorrelation function feature of C/A code signals.The CAPS signal measurement precision is studied by the software approach together with theoretical analysis of the range resolution.Because the conventional Delay Lock Loop (DLL) is vulnerable to the impact of noise,a narrow correlator and multiple correlatore as well as the corresponding discrimination methods of phases are proposed,which improves the robustness of DLL and the code-phase resolution of the measurement.The results show that the Improvement of the DLL structure and the discrimination method are the most important way to improve the ranging resolution.Theoretical analysis and experimental results show that a CAPS receiver could reach a 20-m positioning precision by using three satellites with a supported height from an altimeter.

  4. Effect of biochar amendment on the bioavailability of pesticide chlorantraniliprole in soil to earthworm.

    Science.gov (United States)

    Wang, Ting-Ting; Cheng, Jie; Liu, Xian-Jin; Jiang, Wayne; Zhang, Chao-Lan; Yu, Xiang-Yang

    2012-09-01

    To evaluate the effect of biochar amendment on the bioavailability of chlorantraniliprole (CAP) in soils with different physico-chemical properties, the uptake of CAP from various soils by earthworms was studied. It was observed that the biochar amendment of the soils affected the sorption of CAP, but the magnitude of the sorption enhancement by biochar amendment among the soils was varied, presumably due to the attenuation of the sorptivity of the biochar when amended in the soil. The amendment with biochars leads to a decrease in the bioavailability of CAP in the soils to earthworms, and more prominent for biochar BC850 amendment. In the soil with a CAP concentration of 10 mg kg(-1), the residue of CAP in the earthworm tissues was found to be 9.65 mg kg(-1), in comparison with that the CAP residue was 4.05 mg kg(-1) in BC450 amended soil and 0.59 mg kg(-1) in BC850, respectively. The degree of bioavailability reduction by same level of biochar amendment was different among soils with different properties. The results demonstrate that the properties of soils are important to performance of biochar in soil. PMID:22776710

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. The Meaning of a Compact

    Science.gov (United States)

    Wasescha, Anna

    2016-01-01

    To mark the 30th anniversary of "Campus Compact," leaders from across the network came together in the summer of 2015 to reaffirm a shared commitment to the public purposes of higher education. Campus Compact's 30th Anniversary Action Statement of Presidents and Chancellors is the product of that collective endeavor. In signing the…

  8. The Finslerian compact star model

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Farook; Paul, Nupur [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); De, S.S. [University of Calcutta, Department of Applied Mathematics, Kolkata (India); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India); Jafry, M.A.K. [Shibpur Dinobundhoo Institution, Department of Physics, Howrah, West Bengal (India)

    2015-11-15

    We construct a toy model for compact stars based on the Finslerian structure of spacetime. By assuming a particular mass function, we find an exact solution of the Finsler-Einstein field equations with an anisotropic matter distribution. The solutions are revealed to be physically interesting and pertinent for the explanation of compact stars. (orig.)

  9. Warm compacting behavior of stainless steel powders

    Institute of Scientific and Technical Information of China (English)

    肖志瑜; 柯美元; 陈维平; 召明; 李元元

    2004-01-01

    The warm compacting behaviors of four different kinds of stainless steel powders, 304L, 316L, 410L and 430L, were studied. The results show that warm compaction can be applied to stainless steel powders. The green densities and strengths of compacts obtained through warm compaction are generally higher than those obtained through cold compaction. The compacting behaviors in warm compaction and cold compaction are similar.Under the compacting pressure of 700 MPa, the warm compacted densities are 0. 10 - 0.22 g/cm3 higher than the cold compacted ones, and the green strengths are 11.5 %-50 % higher. The optimal warm compacting temperature is 100 - 110 ℃. In the die wall lubricated warm compaction, the optimum internal lubricant content is 0.2%.

  10. Influence of Conservation Tillage and Soil Water Content on Crop Yield in Dryland Compacted Alfisol of Central Chile Influencia de la Labranza de Conservación y el Contenido de Agua sobre el Rendimiento del Cultivo en un Alfisol compactado del Secano Central de Chile

    Directory of Open Access Journals (Sweden)

    Ingrid Martinez G

    2011-12-01

    Full Text Available Chilean dryland areas of the Mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. An oat (Avena sativa L. cv. Supernova-INIA - wheat (Triticum aestivum L. cv. Pandora-INIA crop rotation was established under the following conservation systems: no tillage (Nt, Nt + contour plowing (Nt+Cp, Nt + barrier hedge (Nt+Bh, and Nt + subsoiling (Nt+Sb, compared to conventional tillage (Ct to evaluate their influence on soil water content (SWC in the profile (10 to 110 cm depth, the soil compaction and their interaction with the crop yield. Experimental plots were established in 2007 and lasted 3 yr till 2009 in a compacted Alfisol. At the end of the growing seasons, SWC was reduced by 44 to 51% in conservation tillage systems and 60% in Ct. Soil water content had a significant (p En Chile, las zonas de clima mediterráneo se caracterizan por suelos altamente degradados y compactados por erosión, lo que requiere el uso de sistemas de labranza conservacionista para mitigar la erosión hídrica, así como incrementar el contenido de agua en el suelo. Se evaluó una rotación avena (Avena sativa L. cv. Supernova-INIA - trigo (Triticum aestivum L. cv. Pandora-INIA establecida bajo los siguientes sistemas conservacionistas: cero labranza (Nt, Nt + curvas de nivel (Nt+Cp, Nt + franjas vivas (Nt+Bh y Nt + subsolado (Nt+Sb, las que fueron comparadas al sistema de labranza convencional (Ct, para evaluar su influencia en el contenido de agua en el suelo (SWC en el perfil (10 a 110 cm profundidad, la compactación del suelo y su interacción con el rendimiento del cultivo. Las parcelas experimentales fueron establecidas 3 años seguidos (2007 al 2009 en un Alfisol compactado. Al final de la temporada, el SWC disminuyó 44 a 51% en los sistemas conservacionistas y 60% en el sistema convencional. El sistema de

  11. Seismic explosion sources on an ice cap

    DEFF Research Database (Denmark)

    Shulgin, Alexey; Thybo, Hans

    2015-01-01

    Controlled source seismic investigation of crustal structure below ice covers is an emerging technique. We have recently conducted an explosive refraction/wide-angle reflection seismic experiment on the ice cap in east-central Greenland. The data-quality is high for all shot points and a full...... crustal model can be modelled. A crucial challenge for applying the technique is to control the sources. Here, we present data that describe the efficiency of explosive sources in the ice cover. Analysis of the data shows, that the ice cap traps a significant amount of energy, which is observed...... as a strong ice wave. The ice cap leads to low transmission of energy into the crust such that charges need be larger than in conventional onshore experiments to obtain reliable seismic signals. The strong reflection coefficient at the base of the ice generates strong multiples which may mask for secondary...

  12. Levels of induced pressure and compaction as caused by forest harvesting operations

    Directory of Open Access Journals (Sweden)

    Paula Cristina Caruana Martins

    2013-03-01

    Full Text Available This study aimed to determine levels of pressure and compaction induced by forest harvesting operations in a Red Latosol (LV under planted eucalyptus. Undisturbed soil samples were collected from layers 0-3 and 15-18 cm and then used in a uniaxial compression test. Sampling was done before and after harvesting operations. Equipment being evaluated included: harvester, feller buncher, forwarder, self-loading adapted tractor, standard truck, wide-tire truck and grapple saw. Average pressures induced by the grapple saw were 320 kPa and 272 kPa, causing compaction in 80% and 20% of samples respectively from layers 0-3 cm and 15-18 cm, which indicates substantial degradation of soil structure in areas where timber is processed. In layer 0-3 cm, average pressures induced by the harvester and by the feller buncher were 240 kPa and 263 kPa respectively, while in layer 15-18 cm pressures were 234 kPa and 239 kPa respectively. The feller buncher caused higher soil compaction than the harvester in layer 0-3 cm, yet in layer 15-18 cm they had similar behavior. All timber forwarding equipment led to soil compaction. The wide-tire truck was the forwarding implement promoting the highest rate of compaction, in both residue conditions. Traffic intensity 7 promoted the highest rate of soil compaction.

  13. 桩台网复合地基加固区沉降研究%Study on Settlement of Pile-Cap-Net Composite Foundation in Stabilization Area

    Institute of Scientific and Technical Information of China (English)

    秦立新

    2014-01-01

    目前,桩台网复合地基沉降计算所需桩土荷载比主要靠经验或试验确定。通过假定桩台间网下凹变形为抛物状、大小等于桩间土下沉量减去桩的下沉量,引入 Jones 经验公式,推导出桩顶、桩间土荷载和桩土荷载比计算公式,采用试算法确定地基沉降。试验对比表明,计算公式具有一定的可靠性。%At present,pressure ratio of pile and soil of pile-cap-net composite foundation used in settlement calculation is determined primary by experience and test.Supposed that deformation curve of net between caps is parabola and sinkage equals to settlement of soil between caps minus compression of piles.By the introduction of experiential formula presented by Jones,pressure of cap and soil surface between caps can be calculated,and pressure ratio of pile and soil between caps can also be calculated.Settlement of foundation can be obtained by trial calculation.The reliability of formula above is proved by test.

  14. Previous cultivation of palisade grass and soil correctives: influence on growth and yield of soybean cultivated under various soil compaction levels Cultivo prévio de braquiarão e corretivos de solo: influência sobre o crescimento e produção da soja cultivada sob vários níveis de compactação do solo

    Directory of Open Access Journals (Sweden)

    Marcos André Silva Souza

    2011-12-01

    Full Text Available Soil compaction directly interferes on crop yield. The objectives of this work were to evaluate the effect of previous cultivation with palisade grass [Urochloa brizantha (C. Hochstetter ex A. Rich. R. Webster cv. Marandu] and the use of soil correctives on the growth and yield of soybeans (Glycine max L. cultivated under various soil compaction levels, in greenhouse conditions. The experiment was conducted in pots (columns of 0.2 m diameter PVC tubes, composed of two rings: the lower ring, 0.4 m in height, received the soil (dystrophic Red Latosol, clayey texture without corrective and a density of 1.0 Mg m-3; and the upper ring, 0,2 m in height, received the treatments of soil correctives and density. The experimental design was fully randomized in a 4 x 6 x 2 factorial outline, being four soil density levels (1.0; 1.20; 1.40 and 1.60 Mg m-3, six soil correctives (without corrective, lime, calcium silicate, gypsum, lime + gypsum and calcium silicate + gypsum and two cultivation systems of the soybean (with and without previous cultivation of palisade grass. Starting from 1.2 Mg m-3 of soil density the soybean growth and yield were decreased. The use of soil correctives and previous soil cultivation with palisade grass decreased the harmful effects of the soil compaction on the soybean growth and yield. For the treatments that received previous cultivation with palisade grass, the soybean growth and yield were higher with application of lime + gypsum and calcium silicate + gypsum.A compactação do solo interfere diretamente sobre a produção das culturas. Neste trabalho, objetivou-se avaliar o efeito do cultivo prévio do braquiarão e o uso de corretivos do solo sobre o crescimento e produção da soja cultivada sob solo com vários níveis de compactação, em condições de casa de vegetação. O experimento foi conduzido em vasos (colunas de tubos de PVC de 0,2 m de diâmetro, compostos por dois anéis: o anel inferior, de 0,4 m de altura

  15. Boundaries of flat compact surfaces

    DEFF Research Database (Denmark)

    Røgen, Peter

    1999-01-01

    This paper deals with the problem: ``Which knots or links in 3-space bound flat (immersed) compact surfaces?''. In a previous paper by the author it was proven that: Any simple closed space curve can be deformed until it bounds a flat orientable compact (Seifert) surface. The main results...... of this paper are: There exist knots that do not bound any flat compact surfaces. The lower bound of total curvature of a knot bounding an orientable non-negatively curved compact surface can, for varying knot type, be arbitrarily much greater than the infimum of curvature needed for the knot to have its knot...... type. The number of $3$-singular points (points of zero curvature or if not then of zero torsion) on the boundary of a flat immersed compact surface is greater than or equal to twice the absolute value of the Euler characteristic of the surface. A set of necessary and, in a weakened sense, sufficient...

  16. Crescimento da parte aérea de plantas cultivadas em vaso, submetidas à irrigação subsuperficial e a diferentes graus de compactação de um Latossolo Vermelho-Escuro distrófico Shoot growth of plants under subsurface irrigation and four degrees of soil compaction

    Directory of Open Access Journals (Sweden)

    Geovani José Silva

    2006-02-01

    Full Text Available A compactação é um processo que pode ocorrer em solos manejados inadequadamente, afetando, direta ou indiretamente, o crescimento e a produção das culturas. Com o objetivo de avaliar o crescimento da parte aérea de plantas, considerando os diferentes graus de compactação subsuperficial, plantas de soja, milho, algodão e Brachiaria brizantha foram cultivadas em vasos com material de um Latossolo Vermelho-Escuro distrófico, sob condição de fornecimento subsuperficial de água. O experimento foi realizado, sob telado, na Faculdade de Agronomia e Medicina Veterinária da UFMT, em vasos de PVC rígido de 195 mm de diâmetro interno, adotando-se delineamento inteiramente casualizado em esquema fatorial 4 x 4 x 5 (quatro espécies, densidades do solo de 1,0; 1,2; 1,4 e 1,5 Mg m-3 e cinco repetições. O conteúdo de água no sistema solo/vaso foi mantido acima de 60 % da capacidade de campo. Ao fim do experimento, mediu-se a altura das plantas, cortaram-se as plantas rente ao solo e foram determinadas a área foliar, a massa seca de frutificações (algodão, soja e milho e a massa seca total da parte aérea. A compactação do solo provocou reduções significativas no crescimento da parte aérea do algodoeiro, milho e soja a partir de 1,4 Mg m-3 e na densidade do solo de 1,5 Mg m-3, para Brachiaria brizantha. A soja apresentou os maiores incrementos das características avaliadas na densidade do solo de 1,2 Mg m-3. A Brachiaria brizantha mostrou-se como a espécie de maior tolerância, enquanto o algodoeiro revelou maior susceptibilidade aos efeitos da compactação. Em geral, o modelo quadrático explicou adequadamente o crescimento das plantas de acordo com a compactação.Compaction is a process that can occur in soils managed inadequately, affecting crop growth and yield directly or indirectly. The shoot development was evaluated as a function of different degrees of subsoil compaction in soybean, corn, cotton, and Brachiaria

  17. Tensile strength of soil cores in relation to aggregate strength, soil fragmentation and pore characteristics

    OpenAIRE

    Munkholm, Lars; Schjønning, Per; Kay, Bev D.

    2002-01-01

    Tensile failure of soil is desirable in tillage. Soil tensile strength estimates most often are obtained from compression tests of dry aggregates. As tillage is performed under moist conditions, it would be highly relevant to measure tensile strength at high water contents. Plough-layer soil was sampled in a compacted soil (PAC) and in a non-compacted reference soil (REF). Tensile strength was measured in a new direct tension test using undisturbed soil cores (4.45 cm in diameter and 5.00...

  18. Approximation of dynamic and quasi-static evolutions in elasto-plasticity by cap models

    OpenAIRE

    Babadjian, Jean-François; Mora, Maria Giovanna

    2015-01-01

    This work is devoted to the analysis of elasto-plasticity models arising in soil mechanics. Contrary to the typical models mainly used for metals, it is required here to take into account plastic dilatancy due to the sensitivity of granular materials to hydrostatic pressure. The yield criterion thus depends on the mean stress and the elasticity domain is unbounded and not invariant in the direction of hydrostatic matrices. In the mechanical literature, so-called cap models have been introduce...

  19. Pharmacy benefit caps and the chronically ill.

    Science.gov (United States)

    Joyce, Geoffrey F; Goldman, Dana P; Karaca-Mandic, Pinar; Zheng, Yuhui

    2007-01-01

    In this paper we examine medication use among retirees with employer-sponsored drug coverage both with and without annual benefit limits. We find that pharmacy benefit caps are associated with higher rates of medication discontinuation across the most common therapeutic classes and that only a minority of those who discontinue use reinitiate therapy once coverage resumes. Plan members who reach their cap are more likely than others to switch plans and increase their rate of generic use; however, in most cases, the shift is temporary. Given the similarities between these plans and Part D, we make some inferences about reforms for Medicare.

  20. Assembling the CMS yoke end-caps

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    A crane is used to piece together one of the end-caps that will provide the path for magnetic flux return on the CMS experiment. A total of six end-cap discs will be assembled before being positioned on the barrel yoke to complete the huge 12 500 tonne cylinder yoke. The magnetic field produced will be greater than any other solenoid created to date at 4 T, 100 000 times greater than the Earth's natural magnetic field, and will store enough energy to melt 18 tonnes of gold.

  1. Design and implementation of the CAPS receiver

    Institute of Scientific and Technical Information of China (English)

    HU YongHui; HUA Yu; HOU Lei; WEI JingFa; WU JianFeng

    2009-01-01

    In this paper,baaed on analyses of the Chinese Area Positioning System (CAPS) satellite (GEO satellite) resources and signal properties,the signal power at the port of the receiver antenna is estimated,and the implementation projects are presented for a switching band C to band L CAPS C/A code receiver integrated with GPS receiver suite and for a CAPS dual frequency P code receiver.A microstrip receiving antenna is designed with high sensitivity and wide beam orientation,the RF front end of the C/A code and P code receivers,and a processor is designed for the navigation baseband.A single frequency CAPS C/A code receiver and a CAPS dual frequency P code receiver are built at the same time.A software process flow is provided,and research on relatively key techniques is also conducted,such as signal searching,code loop and carrier loop algorithms,a height assistant algorithm,a dual frequency difference speed measurement technique,a speed measurement technique using a single frequency source with frequency assistance,and a CAPS time correcting algorithm,according to the design frame of the receiver hardware.Research results show that the static plane positioning accuracy of the CAPS C/A code receiver is 20.5-24.6 m,height accuracy is 1.2-12.8 m,speed measurement accuracy is 0.13-0.3 m/s,dynamic plane positioning accuracy is 24.4 m,height accuracy is 3.0 m,and speed measurement accuracy is 0.24 m/s.In the case of C/A code,the timing accuracy is 200 ha,and it is also shown that the positioning accuracy of the CAPS precise code receiver (1σ) is 5 m from south to north,and 0.8 m from east to west.Finally,research on positioning accuracy is also conducted.

  2. A Compact Ring Design with Tunable Momentum Compaction

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.; /SLAC

    2012-05-17

    A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and predamping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

  3. 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.

  4. Numerical study of bending test on compacted clay by discrete element method: tensile strength determination

    OpenAIRE

    Ammeri, A; Jamei, M; BOUASSIDA, M; Ple, Olivier; Villard, Pascal; Gourc, J. P.

    2009-01-01

    International audience The study of the tensile behaviour of clay is one of the topics which requires a specific lighting especially when one pays a close attention to the pathology of work built with or on clays subjected to significant tensile forces. Therefore, failure or damage of clay, under specific conditions, can be related to tensile stress limit and not to shear stress limit. It is the case of compacted clay liners in landfill cap cover subjected to differential settlements withi...

  5. Geotehnical Properties of Plastic Stabilized Lateritic Soil

    OpenAIRE

    Akinola Johnson Olarewaju

    2016-01-01

    Stabilization is the combination of soils and additives to change its properties and remain in its stable compacted state without undergoing any change under effect of exposure to weather and traffic. Soil stabilization through the reinforced soil construction is an efficient and reliable technique for improving the strength and stability of soils. The lateritic soil used in this study was taken along Papa-Ilaro road Ajegunle at Abalabi, Ogun State, Nigeria and the solid plastic wastes were t...

  6. Influência da imersão em água na resistência mecânica de misturas solo-grits compactadas e curadas com vistas a aplicações em estradas florestais Influence of water submersion on the mechanical strength of compacted and cured soil-grits mixtures for forest roads applications

    Directory of Open Access Journals (Sweden)

    Reginaldo Sérgio Pereira

    2007-01-01

    ranging from 4 to 28 %, compacted at the intermediate and modified compaction efforts, and cured during 0, 7 and 28 days. Laboratory tests were performed as follow: (i CBR: tests were performed following the standard procedure, i.e. after 4 days water submersion before specimen penetration, and without submersion; and (ii UCS: tests were performed following the Brazilian standard procedure, i.e. after 4 hours specimen submersion before testing, and without water submersion. The laboratory testing program data support that water submersion significantly influenced the tested mechanical strength parameters, which were dependent of the type of assay and soil, percentage of grits waste, compaction effort and cure.

  7. 土壤紧实胁迫对玉米苗期生长与钙吸收的影响%Effect of Soil Compaction Stress on the Growth of Corn and Calcium Absorption at the Seedling Stage

    Institute of Scientific and Technical Information of China (English)

    徐海; 王益权; 王永健; 徐爽; 李鹏

    2011-01-01

    With the aim to evaluate the influence of soil hardness to corn growth and calcium absorption, five levels of soil hardness (soil bulk density: 1.1, 1.2, 1.3, 1.4 and 1. 5 g/cm3) were established in the pot experiment. There was no significant influence of soil hardness to corn growth in the first 15 d after seeding, however, it inhibited aboveground corn growth in the following days. Root dry mass and activity both decreased because of the high soil hardness which had a negative effect on calcium absorption. The highest calcium content (1. 67% ) occurred in the treatment with 1. 2 g/cm3 soil hardness. The increase of soil hardness caused root activity decrease which led to the decrease of calcium absorption, thus, lower crop resistance to disease and cause in senescence in advance. It was concluded that too high or too low density of soil bulk was disadvantage to the crop growth.%为揭示玉米对不同土壤紧实胁迫的响应程度与机理,以钙素为依据,设置土壤容重分别为1.1、1.2、1.3、1.4和1.5 g/cm3等5个水平玉米盆栽试验,以探讨土壤紧实度对玉米苗期生长及对钙素吸收的影响.试验结果表明:玉米从播种到生长15d期间,其生长对土壤紧实并不敏感,而15d之后,地上部分生长速度随土壤容重增加而受到抑制;而根系生长也由于土壤的紧实胁迫而受阻,根系干物质质量下降,根系活力减小,影响钙素养分的吸收;玉米苗中全钙含量最高值(1.67%)出现在容重1.2 g/cm3处理中,土壤紧实的增加会导致根系活性减小,从而使作物根系对钙素的吸收减少、作物抗性下降,导致作物提前衰老.因此,土壤容重影响土壤中养分的有效性,土壤过松或过紧均不利于作物的生长.

  8. CAP Reform and the Doha Development Agenda

    NARCIS (Netherlands)

    van Dijck, P.; Faber, G.

    2004-01-01

    The CAP reforms that the EU accepted in June 2003 will partially decouple direct income payments to farmers from production and make these payments conditional on cross-compliance. The reforms are driven by enlargement of EU membership, budgetary constraints, mounting pressures from diverse animal w

  9. The Effectiveness of Caps on Political Lobbying

    NARCIS (Netherlands)

    Matejka, M.; Onderstal, A.M.; De Waegenaere, A.M.B.

    2002-01-01

    In this paper, we analyze a lobby game, modelled as an all-pay auction in which interest groups submit bids in order to obtain a political prize.The bids are restricted to be below a cap imposed by the government.For both an incomplete and a complete information setting we show the following results

  10. INTERNATIONAL WHEAT PRICE TRANSMISSION AND CAP REFORM

    OpenAIRE

    Thompson, Stanley R.; Bohl, Martin T.

    1999-01-01

    We illustrate how CAP policy reforms influence the transmission of world prices to domestic markets. Monthly wheat price data in Germany are used to obtain price transmission elasticities. Correctly accounting for structural breaks and the time series properties of the data yield transmission elasticities that differ dramatically among policy regimes.

  11. Successful treatment of cap polyposis with infliximab.

    Science.gov (United States)

    Bookman, Ian D; Redston, Mark S; Greenberg, Gordon R

    2004-06-01

    Cap polyposis is a disorder characterized by bloody diarrhea with rectosigmoid polyps covered by a cap of fibropurulent exudate. The pathogenesis is unknown, but histological features suggest that mucosal prolapse may play a role. Drug therapies are usually unsuccessful, and treatment requires sigmoid resection or, if the disease recurs after initial surgical resection, panproctocolectomy. We report the case of a 36-year-old woman with characteristic clinical, endoscopic, and histological features of cap polyposis. Investigations included normal anorectal manometry and defecography, without evidence of prolapse. The patient's disease was unresponsive to treatment with mesalamine, antibiotics, lidocaine enemas, and corticosteroids. One infusion of infliximab 5 mg/kg provided dramatic symptomatic improvement but minimal endoscopic or histological change. After 4 infliximab infusions at 8-week intervals, endoscopy of the rectum and sigmoid colon was normal, and biopsies showed complete histological resolution of the inflammatory process. Well-being with normal endoscopy and histology has been maintained at 38 months, without further treatment. It was concluded that infliximab is effective therapy for cap polyposis and avoids the requirement for surgery. No clinical evidence was obtained to support mucosal prolapse as a causative factor, but the response to infliximab suggests a role for tumor necrosis factor-alpha in the pathogenesis of this disorder. PMID:15188181

  12. Knowledge Management at Cap Gemini Nederland

    NARCIS (Netherlands)

    M.J. Vlaanderen (Marie Jose)

    1998-01-01

    textabstractThe theme of this paper is knowledge management (KM) at an organization that provides information technology (IT) services. It is based on the results of a KM-survey of the Finance Division of Cap Gemini (CG) conducted during the spring of 1997.

  13. ATLAS: End-cap Toroid assembly

    CERN Multimedia

    2006-01-01

    In building 191 and building 180- assembly of this massive piece.To reach the top of the end-cap the cranes has to be used and during the assembly you can see welding and hear many tools running background.

  14. Integrated firn elevation change model for glaciers and ice caps

    Science.gov (United States)

    Saß, Björn; Sauter, Tobias; Braun, Matthias

    2016-04-01

    We present the development of a firn compaction model in order to improve the volume to mass conversion of geodetic glacier mass balance measurements. The model is applied on the Arctic ice cap Vestfonna. Vestfonna is located on the island Nordaustlandet in the north east of Svalbard. Vestfonna covers about 2400 km² and has a dome like shape with well-defined outlet glaciers. Elevation and volume changes measured by e.g. satellite techniques are becoming more and more popular. They are carried out over observation periods of variable length and often covering different meteorological and snow hydrological regimes. The elevation change measurements compose of various components including dynamic adjustments, firn compaction and mass loss by downwasting. Currently, geodetic glacier mass balances are frequently converted from elevation change measurements using a constant conversion factor of 850 kg m‑³ or the density of ice (917 kg m‑³) for entire glacier basins. However, the natural conditions are rarely that static. Other studies used constant densities for the ablation (900 kg m‑³) and accumulation (600 kg m‑³) areas, whereby density variations with varying meteorological and climate conditions are not considered. Hence, each approach bears additional uncertainties from the volume to mass conversion that are strongly affected by the type and timing of the repeat measurements. We link and adapt existing models of surface energy balance, accumulation and snow and firn processes in order to improve the volume to mass conversion by considering the firn compaction component. Energy exchange at the surface is computed by a surface energy balance approach and driven by meteorological variables like incoming short-wave radiation, air temperature, relative humidity, air pressure, wind speed, all-phase precipitation, and cloud cover fraction. Snow and firn processes are addressed by a coupled subsurface model, implemented with a non-equidistant layer

  15. 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.

  16. [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

  17. Effects of closure cap and liner on contaminant release rates from grouted wastes

    International Nuclear Information System (INIS)

    This paper describes a groundwater modeling study of waste disposal concepts using grouted waste forms. The focus of the study is on the effects of clay caps and concrete vaults on contaminant migration. The authors modeled three waste disposal scenarios: (1) Grouted waste was solidified in an earthen trench and covered with soil, there was no vault and no cap; (2) grouted waste was solidified in an earthen trench, the entire waste disposal facility was then closed under a clay cap; (3) grouted waste was solidified in a concrete vault and protected by the same closure as in 2. Because of the huge contrast in hydraulic conductivities and highly non-linear multi-phase flow characteristics, these waste disposal concepts presented a difficult problem for numerical simulation. Advanced fluid flow and contaminant transport codes were used to solve the problem. Among the codes tested, ECLIPSE out-performed other codes in speed, accuracy (smaller material balance errors) and capability in handling sophisticated scenarios. The authors used nitrate as a tracer for the simulation. Nitrate does not absorb in the solid phase and does not decay. As a result, predicted release rate based on nitrate is conservative. They also assumed that the facility is intact for 10,000 years. In other words, properties of the materials used for this study do not change with time. Predicted peak flux for the no vault and no closure case was 5.8 x 10-4 per year at 12 years. If a clay cap was installed, predicted peak flux was 8.5 x 10-5 per year at 110 years. If the grout was disposed in a concrete vault and covered by a clay cap, predicted peak flux became 4.4 x 10-6 per year at 8,000 years. Both concrete liner and clay cap can reduce the rate of contaminant release to the water table and delay the peak time

  18. Compact Grism Spectrometer

    Science.gov (United States)

    Teare, S. W.

    2003-05-01

    Many observatories and instrument builders are retrofitting visible and near-infrared spectrometers into their existing imaging cameras. Camera designs that reimage the focal plane and have the optical filters located in a pseudo collimated beam are ideal candidates for the addition of a spectrometer. One device commonly used as the dispersing element for such spectrometers is a grism. The traditional grism is constructed from a prism that has had a diffraction grating applied on one surface. The objective of such a design is to use the prism wedge angle to select the desired "in-line" or "zero-deviation" wavelength that passes through on axis. The grating on the surface of the prism provides much of the dispersion for the spectrometer. A grism can also be used in a "constant-dispersion" design which provides an almost linear spatial scale across the spectrum. In this paper we provide an overview of the development of a grism spectrometer for use in a near infrared camera and demonstrate that a compact grism spectrometer can be developed on a very modest budget that can be afforded at almost any facility. The grism design was prototyped using visible light and then a final device was constructed which provides partial coverage in the near infrared I, J, H and K astronomical bands using the appropriate band pass filter for order sorting. The near infrared grism presented here provides a spectral resolution of about 650 and velocity resolution of about 450 km/s. The design of this grism relied on a computer code called Xspect, developed by the author, to determine the various critical parameters of the grism. This work was supported by a small equipment grant from NASA and administered by the AAS.

  19. Compact instantaneous water heater

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Jorge G.W.; Machado, Antonio R.; Ferraz, Andre D.; Rocha, Ivan C.C. da; Konishi, Ricardo [Companhia de Gas de Santa Catarina (SCGAS), Florianopolis, SC (Brazil); Lehmkuhl, Willian A.; Francisco Jr, Roberto W.; Hatanaka, Ricardo L.; Pereira, Fernando M.; Oliveira, Amir A.M. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-07-01

    This paper presents an experimental study of combustion in an inert porous medium in a liquid heating device application. This project aims to increase efficiency in the application of natural gas in residential and commercial sectors with the use of advanced combustion and heat transfer. The goal is to facilitate the development of a high performance compact water heater allowing hot water supply for up to two simultaneous showers. The experiment consists in a cylindrical porous burner with an integrated annular water heat exchanger. The reactants were injected radially into the burner and the flame stabilizes within the porous matrix. The water circulates in a coiled pipe positioned at the center of the burner. This configuration allows for heat transfer by conduction and radiation from the solid matrix to the heat exchanger. This article presented preliminary experimental results of a new water heater based on an annular porous burner. The range of equivalence ratios tested varied from 0.65 to 0.8. The power range was varied from 3 to 5 kW. Increasing the equivalence ratio or decreasing the total power input of the burner resulted in increased thermal efficiencies of the water heater. Thermal efficiencies varying from 60 to 92% were obtained. The condition for the goal of a comfortable bath was 20 deg C for 8-12 L/min. This preliminary prototype has achieved water temperature of 11deg C for 5 L/min. Further optimizations will be necessary in order to achieve intense heating with high thermal efficiency. (author)

  20. Demanda de potência de uma semeadora com dois tipos de sulcadores em áreas compactadas pelo pisoteio de animais no sistema integração lavoura-pecuária Soil compaction and power of one planter with two types of sowers in the system integration cattle-raising agriculture

    Directory of Open Access Journals (Sweden)

    Veruschka R. M. Andreolla

    2006-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a potência requerida na barra de tração do trator por uma semeadora com dois tipos de elementos sulcadores, na semeadura da soja, em áreas compactadas pelo pisoteio de animais em sistema de integração lavoura-pecuária. Foi utilizado o delineamento em parcela subdividida inteiramente casualizado, sendo os tratamentos principais compostos de solo úmido com pastejo, solo seco com pastejo e solo sem pastejo, e nos secundários foram utilizados sulcadores de haste ou discos duplos. Foram avaliadas a densidade e a resistência do solo à penetração, a força de tração exercida pela semeadora, a velocidade e a potência requerida na barra de tração do trator. As alterações no solo causadas pelo pisoteio do gado não foram suficientes para interferir na demanda de potência. Entre os elementos, as semeadoras com sulcadores de disco exerceram menor força de tração, e a velocidade de deslocamento do conjunto foi maior.The aim of this work was to evaluate the power required in the drawbar of a seeder with two types of soil opening seed placement in soybean sowing, in areas compacted by the trample of animals in the system of integration cattle-raising agriculture. The experiments was performed in a complete randomized split-plot design, being the mean treatments moisture soil with pasture; dry soil with pasture and soil without pasture, and the secondary treatments hoe opener and staggered doubles-discs opener. The bulk density, cone index, drawbar, speed and power in the drawbar and engine were evaluated. The alterations in the physical properties of the soil, caused by the trampling of the cattle they were not enough to interfere in the power demand. Among the mechanisms, the planters with staggered doubles-discs opener exercised smaller traction force and larger speed.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Parameter Estimation for Coupled Hydromechanical Simulation of Dynamic Compaction Based on Pareto Multiobjective Optimization

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-01-01

    Full Text Available This paper presented a parameter estimation method based on a coupled hydromechanical model of dynamic compaction and the Pareto multiobjective optimization technique. The hydromechanical model of dynamic compaction is established in the FEM program LS-DYNA. The multiobjective optimization algorithm, Nondominated Sorted Genetic Algorithm (NSGA-IIa, is integrated with the numerical model to identify soil parameters using multiple sources of field data. A field case study is used to demonstrate the capability of the proposed method. The observed pore water pressure and crater depth at early blow of dynamic compaction are simultaneously used to estimate the soil parameters. Robustness of the back estimated parameters is further illustrated by a forward prediction. Results show that the back-analyzed soil parameters can reasonably predict lateral displacements and give generally acceptable predictions of dynamic compaction for an adjacent location. In addition, for prediction of ground response of the dynamic compaction at continuous blows, the prediction based on the second blow is more accurate than the first blow due to the occurrence of the hardening and strengthening of soil during continuous compaction.

  4. What Is Business's Social Compact?

    Science.gov (United States)

    Avishai, Bernard

    1994-01-01

    Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

  5. Compact energy conversion module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes like structural health monitoring (SHM). NASA...

  6. Compact, Ultrasensitive Formaldehyde Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase II proposal seeks to develop a compact UV laser ?based sensor for Earth science and planetary atmosphere exploration....

  7. Countably determined compact abelian groups

    CERN Document Server

    Dikranjan, Dikran

    2008-01-01

    For an abelian topological group G let G^* be the dual group of all continuous characters endowed with the compact open topology. A subgroup D of G determines G if the restriction homomorphism G^* --> D^* of the dual groups is a topological isomorphism. Given a scattered compact subset X of an infinite compact abelian group G such that |X|compact abelian group determined by its countable subgroup must be metrizable. This gives a negative answer to questions of Comfort, Hernandez, Macario, Raczkowski and Trigos-Arrieta, as well as provides short proofs of main results established in three manuscripts by these authors.

  8. Compact, Airborne Multispecies Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase I proposal seeks to develop a compact mid-infrared laser spectrometer to benefit Earth science research activities. To...

  9. Facially amphiphilic thiol capped gold and silver nanoparticles

    OpenAIRE

    Bhat, Shreedhar; Maitra, Uday

    2008-01-01

    A series of bile acid-derived facially amphiphilic thiols have been used to cap sliver and gold nanoparticles. The self-assembling properties of these steroid-capped nanoparticles have been investigated and reported in this article.

  10. Facially amphiphilic thiol capped gold and silver nanoparticles

    Indian Academy of Sciences (India)

    Shreedhar Bhata; Uday Maitra

    2008-11-01

    A series of bile acid-derived facially amphiphilic thiols have been used to cap sliver and gold nanoparticles. The self-assembling properties of these steroid-capped nanoparticles have been investigated and reported in this article.

  11. Compact ground heat exchangers in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Hellstroem, G. [Dept. of Mathematical Physics, Lund Univ. (Sweden); Rosen, B. [Swedish Geotechnical Inst., Linkoeping (Sweden)

    2004-12-01

    About 30,000 ground-coupled heat pumps are currently installed each year in Sweden. Of these, 70-80% use vertical boreholes rock, whereas the remaining part uses horizontal loops. Vertical boreholes are considered to be a technically safer installation, since there is little risk of accidental damage to the pipes. The house owners also appreciate that there is less impact of excavation and possible frost heave in their garden. A research project aimed at developing compact shallow ground heat exchangers was started in 2001 as a cooperation between Lund University and the Swedish Geotechnical Institute funded by the Swedish Research Council FORMAS and the Swedish Energy Agency. The purpose is to reduce the ground area and the trench length required for installation of cost-effective ground heat exchangers in soil to be used in Swedish climatic and geological conditions. The project is carried out in cooperation with installers and heat pump manufacturers. (orig.)

  12. Compact Massive Object in Galaxies

    CERN Document Server

    Melo, I Tosta e

    2016-01-01

    The central regions of galaxies show the presence of super massive black holes and/or very dense stellar clusters. Both objects seem to follow similar host-galaxy correlations, suggesting that they are members of the same family of Compact Massive Objects. We investigate here a huge data collection of Compact Massive Objects properties to correlate them with absolute magnitude, velocity dispersion and mass of their host galaxies.

  13. Termite activity in relation to natural grassland soil attributes

    OpenAIRE

    Kaschuk, G.; Pires Santos, J.C.; J.A. Almeida; Sinhorati, D.S.; Berton-Junior, J.F.

    2006-01-01

    Soil-feeding termites transport soil for mound building, and this process can affect soil characteristics. To verify the influence of soil termite activity on soil characteristics, samples were collected from top, bottom and center of termite mounds, and of the adjacent area, to assess chemical and physical properties and mineralogical composition. Four replicates of termite mounds and respective adjacent areas were randomly sampled in Lages, Capão Alto, Painel, São José do Cerrito and Coxilh...

  14. Exploring plasmonic coupling in hole-cap arrays

    OpenAIRE

    Schmidt, Thomas M.; Maj Frederiksen; Vladimir Bochenkov; Sutherland, Duncan S

    2015-01-01

    The plasmonic coupling between gold caps and holes in thin films was investigated experimentally and through finite-difference time-domain (FDTD) calculations. Sparse colloidal lithography combined with a novel thermal treatment was used to control the vertical spacing between caps and hole arrays and compared to separated arrays of holes or caps. Optical spectroscopy and FDTD simulations reveal strong coupling between the gold caps and both Bloch Wave-surface plasmon polariton (BW-SPP) modes...

  15. 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

  16. 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

  17. Acúmulo de macronutrientes na soja influenciado pelo cultivo prévio do capim-marandu, correção e compactação do solo Macronutrient accumulation in the soybean influenced by prior cultivation of Marandu grass and soil remediation and compaction

    Directory of Open Access Journals (Sweden)

    Marcos André Silva Souza

    2012-12-01

    Full Text Available O presente trabalho foi desenvolvido com o objetivo de avaliar o efeito do cultivo prévio do capim-Marandu (Brachiaria brizantha cv. Marandu, da aplicação de corretivos e da compactação do solo no acúmulo de macronutrientes pela soja cultivada em sucessão. O delineamento experimental foi inteiramente casualizado em esquema fatorial 4 x 6 x 2, com três repetições. Os fatores de estudo foram quatro densidades do solo: 1,0; 1,20; 1,40 e 1,60 Mg m-3; seis tratamentos de correção: 1 controle, sem correção; 2 calcário; 3 silicato de cálcio; 4 gesso; 5 calcário + gesso; 6 silicato de cálcio + gesso; além de dois sistemas de cultivo: com e sem cultivo prévio do capim-Marandu. As unidades experimentais foram compostas por vasos de tubos de PVC de 20 cm de diâmetro, compostos por dois anéis: o anel inferior, de 40 cm de altura, recebeu o solo sob condições naturais e densidade de 1,0 Mg m-3; o anel superior, com 20 cm de altura representando 6,28 dm³, recebeu os tratamentos de densidades, correção e gesso como descrito adiante. Em cada um foram conduzidas três plantas de soja (cv. Conquista até o final do ciclo, quando o acúmulo de macronutrientes pela cultura foi avaliado. Os resultados mostraram que o cultivo prévio do capim-Marandu e o uso de corretivos amenizaram os efeitos negativos da compactação do solo sobre a nutrição da soja. A utilização de corretivos do solo contribuiu para o aumento no acúmulo de macronutrientes na parte aérea da soja, porém o incremento na compactação diminuiu o acúmulo de N, P, K, Ca, Mg e S. A compactação do solo persistiu parcialmente mediante o cultivo prévio com o capim marandu.The present work was developed with the objective of evaluating the effect of the prior cultivation of marandu grass (Brachiaria brizantha cv. Marandu, conditioning applications and soil compaction on macronutrient accumulation in soybeans grown under successive cultivation. The experimental design

  18. Quantification of summertime water ice deposition on the Martian north polar ice cap

    CERN Document Server

    Brown, Adrian J; Becerra, Patricio; Byrne, Shane

    2015-01-01

    We use observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of the north polar cap during late summer for two Martian years, to monitor the complete summer cycle of albedo and water ice grain size in order to place quantitative limits of the amount of water ice deposited in late summer. We establish here for the first time the complete spring to summer cycle of water ice grain sizes on the north polar cap. The apparent grain sizes grow until Ls=132, when they appear to shrink again, until they are obscured at the end of summer by the north polar hood. Under the assumption that the shrinking of grain sizes is due to the deposition of find grained ice, we quantify the amount of water ice deposited per Martian boreal summer, and estimate the amount of water ice that must be transported equatorward. Interestingly, we find that the relative amount of water ice deposited in the north cap during boreal summer (0.7-7 microns) is roughly equivalent to the average amount of water ice depos...

  19. CMS end-cap yoke at the detector's assembly site.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The magnetic flux generated by the superconducting coil in the CMS detector is returned via an iron yoke comprising three end-cap discs at each end (end-cap yoke) and five concentric cylinders (barrel yoke). This picture shows the first of three end-cap discs (red) seen through the outer cylinder of the vacuum tank which will house the superconducting coil.

  20. Numerical and experimental investigations of aluminium powder compaction; Numerische und experimentelle Untersuchungen zum Pulverpressen von Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Hanini, K.; Doege, E.; Schmidt-Juergensen, R. [Institut fuer Umformtechnik und Umformmaschinen, (IFUM) Universitaet Hannover, Welfengarten 1A, 30167 Hannover (Germany)

    2003-08-01

    The FEM simulation is a powerful means which can drastically reduce the time to production and costs in the optimization of powder forming processes. The current paper investigates experimentally and numerically die compaction of aluminium powder. The plastic deformation is formulated by using the Drucker-Prager-Cap-model. This yield criterion describes the compressibility of porous bodies and allows the prediction of crack formation in the green compact. Axial compaction tests have been performed to determine material parameters for hardening. Simulation examples are presented to demonstrate the ability of the model to compute the distribution of the relative density. Furthermore, the compaction of an axisymmetric workpiece was simulated in order to determine optimal tools kinematics and to avoid crack formation. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Die Auslegung und Optimierung pulvertechnologischer Umformverfahren basiert bisher zu einem grossen Teil auf Erfahrungswissen. Die numerische Simulation bietet hierbei eine kosten- und zeitsparende Alternative. Besonders hat sich die Finite-Elemente-Methode (FEM) als leistungsfaehiges Simulationsverfahren bewaehrt. Im Rahmen dieser Arbeit wird das Pulverpressen von Aluminiumpulver numerisch und experimentell untersucht. Hierbei wird das Drucker-Prager-Cap-Modell verwendet, um das kompressible Verhalten des Pulvers abzubilden und moegliche Rissbildungen waehrend des Pressvorgangs vorherzusagen. Durch Pressversuche werden die Materialkennwerte fuer dieses Modell hinsichtlich der Verdichtung und Verfestigung des Aluminiumpulvers ermittelt. Der Pressvorgang wird anhand ausgewaehlter Referenzbauteile simuliert. Von besonderem Interesse ist hierbei die Berechnung der Verteilung der relativen Dichte und die Vermeidung der Rissbildung durch Optimierung der Stempelkinematik. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  1. Effects of Skidder Passes and Slope on Soil Disturbance in Two Soil Water Contents

    OpenAIRE

    Naghdi, Ramin; Solgi, Ahmad

    2014-01-01

    Skidding operations induce changes in soil physical properties, which have the potential to impact soil sustainability and forest productivity. Our objective was to investigate the effects of traffic frequency, trail slope, and soil moisture content on soil compaction, total porosity and rut depth. Treatments included a combination of three different traffic intensities (3, 7, and 14 passes), three levels of slopes ( 20%), and two levels of soil moisture content (18% and 32...

  2. Do Current European Policies Prevent Soil Threats and Support Soil Functions?

    OpenAIRE

    Nadia Glæsner; Katharina Helming; Wim de Vries

    2014-01-01

    There is currently no legislation at the European level that focuses exclusively on soil conservation. A cross-policy analysis was carried out to identify gaps and overlaps in existing EU legislation that is related to soil threats and functions. We found that three soil threats, namely compaction, salinization and soil sealing, were not addressed in any of the 19 legislative policies that were analyzed. Other soil threats, such as erosion, decline in organic matter, loss of biodiversity and ...

  3. Greening CAP payments: a missed opportunity?

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Alan

    2013-01-15

    At an important point in the current reform of the Common Agricultural Policy (CAP), a new IIEA policy brief by Professor Alan Matthews, one of the EU’s foremost experts on the topic, considers proposals to green direct farm payments. Professor Matthews argues that proposed greening of direct payments – the key innovation in the current round of CAP Reform – look likely to fail. While greening may survive as a concept, the likely outcome of the negotiations between Agriculture Ministers and the European Parliament will deliver little practical environmental benefit. The paper examines the rationale underpinning greening, arguing that it exists to justify the continuation of a large agricultural budget, explores reasons for the apparent failure of the proposals, and reflects on the implications for future efforts to better integrate environmental objectives into EU agriculture policy. This is the first in a series of Environment Nexus policy briefs by leading experts in the fields of agriculture, energy, climate change and water.

  4. Should we geoengineer larger ice caps?

    CERN Document Server

    Haqq-Misra, Jacob

    2015-01-01

    The climate of Earth is susceptible to catastrophes that could threaten the longevity of human civilization. Geoengineering to reduce incoming solar radiation has been suggested as a way to mediate the warming effects of contemporary climate change, but a geoengineering program for thousands of years could also be used to enlarge the size of the polar ice caps and create a permanently cooler climate. Such a large ice cap state would make Earth less susceptible to climate threats and could allow human civilization to survive further into the future than otherwise possible. Intentionally extending Earth's glacial coverage will require uninterrupted commitment to this program for millenia but would ultimately reach a cooler equilibrium state where geoengineering is no longer needed. Whether or not this program is ever attempted, this concept illustrates the need to identify preference among potential climate states to ensure the long-term success of civilization.

  5. Status of the AlCap experiment

    CERN Document Server

    Litchfield, R Phillip

    2015-01-01

    The AlCap experiment is a joint project between the COMET and Mu2e collaborations. Both experiments intend to look for the lepton-flavour violating conversion $\\mu + A \\rightarrow e + A$, using tertiary muons from high-power pulsed proton beams. In these experiments the products of ordinary muon capture in the muon stopping target are an important concern, both in terms of hit rates in tracking detectors and radiation damage to equipment. The goal of the AlCap experiment is to provide precision measurements of the products of nuclear capture on Aluminium, which is the favoured target material for both COMET and Mu2e. The results will be used for optimising the design of both conversion experiments, and as input to their simulations. Data was taken in December 2013 and is currently being analysed.

  6. Compactação do solo de diferentes classes texturais em áreas de produção de cana-de-açúcar Soil compaction of different textural classes in areas of sugarcane production

    Directory of Open Access Journals (Sweden)

    Renato Paiva de Lima

    2013-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a existência de camadas compactadas, em três diferentes classes texturais de solos. O estudo foi desenvolvido em áreas, sob cultivo de cana-de-açúcar, da Fazenda Guanabara, localizada no município de Nova Olímpia, Mato Grosso, Brasil. Para coleta dos dados, foi utilizado um penetrômetro de impacto, modelo IAA/Planalsucar, para avaliação da resistência à penetração (RP, em três diferentes classes texturais (Areia Franca, Franco - Argilo- Arenosa e Muito Argilosa. O solo de classe textural franco-argilo-arenosa apresentou os maiores valores de resistência à penetração, entre as três classes. As classes texturais franco-arenosa e muito argilosa comportaram-se de forma semelhante, em todas as camadas. Houve semelhança na resistência à penetração das três classes texturais na camada 0,3-0,4 m.The purpose of this study was to evaluate the existence of compacted layers in three different textural classes located in production areas of sugarcane. The study was conducted in production areas of sugarcane at Fazenda Guanabara, located at municipality of New Olympia, Mato Grosso state, Brazil. Data collection was conducted using an impact penetrometer, model IAA/Planalsucar, evaluating the penetration resistance in three different texture (Loam Sandy, Sandy Clay Loam and Clay. Loam Sandy and Clay textures showed the highest penetration resistance. Loam Sandy and Clay textures behaved very similarly in all layers. There were similar values of penetration resistance of the three classes in 0.3-0.4 m layer.

  7. ATLAS End-cap Part II

    CERN Multimedia

    2007-01-01

    The epic journey of the ATLAS magnets is drawing to an end. On Thursday 12 July, the second end-cap of the ATLAS toroid magnet was lowered into the cavern of the experiment with the same degree of precision as the first (see Bulletin No. 26/2007). This spectacular descent of the 240-tonne component, is one of the last transport to be completed for ATLAS.

  8. Polar cap size metrics study at CCMC

    Science.gov (United States)

    Rastaetter, L.; Kuznetsova, M. M.; Hesse, M.; Gombosi, T. I.; Raeder, J.; Weimer, D.

    2005-12-01

    The Community-Coordinated Modeling Center (CCMC) tests space physics models covering space from the Sun's corona to the Earth's ionosphere and makes them available for researchers through a run-on-request capability. The polar cap size and location as observed by global auroral imagers is used as a basis model to study the performance of global MHD simulation models and statistical models of the auroral ionosphere. With good confidence one can assume that auroral emissions are located within the closed magnetic field lines in a narrow region adjacent to the boundary of the open field line region of the polar cap. In this study we are using imager data from POLAR (FUV) for several events from 1997 to 2000 for which reasonable coverage is available. Simulation runs have been performed using the global magnetospheric models BATSRUS (T. Gombosi et al., U. Michigan) and OpenGGCM (J. Raeder, U. New Hampshire) as well as the Weimer (2000,2005) field-aligned current models (D. Weimer, Mission Research Corp.) fed with upstream solar wind data from the ACE or Geotail satellites. In addition to direct field line tracings available from the 3D MHD model outputs, we use field-aligned currents from both MHD models and the Weimer-2K model to determine the polar cap boundary by using the position of the maximum absolute FAC value in 16 local time sectors. We define skill scores that measure the agreement in the polar cap sizes and location between measurements and models as an example of implementations of metrics to track model performance and apply the analysis to a number of storm event days.

  9. Particle Entrainment in Spherical-Cap Wakes

    OpenAIRE

    Warncke, N.G.W.; Delfos, R.; Ooms, G.; Westerweel, J.

    2011-01-01

    In this work we study the preferential concentration of small particles in the turbulent wake behind a spherical-cap object. We present a model predicting the mean particle concentration in the near-wake as a function of the characteristic Stokes number of the problem, the turbulence level and the Froude number. We compare the model with our experimental results on this flow, measured in a vertical water tunnel.

  10. Translated origin spherical cap harmonic analysis

    OpenAIRE

    De Santis, A.; Istituto Nazionale di Geofisica, Roma, Italy

    1991-01-01

    The method of spherical cap harmonic analysis (SCHA), due to Haines (1985) is appropriate for regional geomagnetic field modelling as it includes the required potential field constraints and, for a given number of model parameters, describes shorter wavelength features than a global spherical harmonic model. If the origin of the coordinate system is moved from the centre of the Earth towards the surface then the Earth's surface is no longer equidistant from the origin. At the Earth's surface ...

  11. Soil physical properties affecting soil erosion in tropical soils

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    -estimated air-filled pore volumes. The largest macropores were characterized on three-dimensional images acquired using an x-ray medical CT scanner. We wanted to evaluate, to what extent the compaction affected soil pore geometries and volumes. The combination of diffusive and advective gas transport......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...

  13. Pulp-Capping with Mineral Trioxide Aggregate

    Directory of Open Access Journals (Sweden)

    Peycheva Kalina

    2015-11-01

    Full Text Available There are two considerations for direct pulp capping - accidental mechanical pulp exposure and exposure caused by caries. Mineral trioxide aggregate (MTA was used as pulp-capping material to preserve the vitality of the pulpal tissues. Follow-up examinations revealed that treatment was successful in preserving pulpal vitality and continued development of the tooth. On the basis of available information, it appears that MTA is the material of choice for some clinical applications. Material and methods: Cases 18 - 8 teeth with grey MTA, 10 teeth with white MTA; diagnose: Pulpitis chronica ulcerosa, Electro pulpal test (EOD - 30-35 μA, pre-clinical X-ray - without changes in the structures, follow ups for 4 years. Successful treatments: without clinical symptoms and changes in the X-rays: 5 teeth with grey MTA, 8 teeth with white MTA for period of 4 years. Unsuccessful treatments: Clinical symptoms and sometimes changes in the X-ray: 3 with grey MTA, 2 with white MTA. MTA is an appropriate material for pulp-capping and follow-up examinations revealed that the treatment was successful in preserving pulpal vitality.

  14. Compact boson stars in K field theories

    Science.gov (United States)

    Adam, C.; Grandi, N.; Klimas, P.; Sánchez-Guillén, J.; Wereszczyński, A.

    2010-11-01

    We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.

  15. Compact boson stars in K field theories

    CERN Document Server

    Adam, C; Klimas, P; Sánchez-Guillén, J; Wereszczynski, A

    2009-01-01

    We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.

  16. Co-compact Gabor Systems on Locally Compact Abelian Groups

    DEFF Research Database (Denmark)

    Jakobsen, Mads Sielemann; Lemvig, Jakob

    2016-01-01

    characterization results via the Zak transform. From these results we derive non-existence results for critically sampled continuous Gabor frames. We obtain general characterizations in time and in frequency domain of when two Gabor generators yield dual frames. Moreover, we prove the Walnut and Janssen......-compact subgroups. Our results only rely on the assumption that either one of the translation and modulation group (in some cases both) are co-compact subgroups of the time and frequency domain. This presentation offers a unified approach to the study of continuous and the discrete Gabor frames....

  17. Viral RNAs are unusually compact.

    Directory of Open Access Journals (Sweden)

    Ajaykumar Gopal

    Full Text Available A majority of viruses are composed of long single-stranded genomic RNA molecules encapsulated by protein shells with diameters of just a few tens of nanometers. We examine the extent to which these viral RNAs have evolved to be physically compact molecules to facilitate encapsulation. Measurements of equal-length viral, non-viral, coding and non-coding RNAs show viral RNAs to have among the smallest sizes in solution, i.e., the highest gel-electrophoretic mobilities and the smallest hydrodynamic radii. Using graph-theoretical analyses we demonstrate that their sizes correlate with the compactness of branching patterns in predicted secondary structure ensembles. The density of branching is determined by the number and relative positions of 3-helix junctions, and is highly sensitive to the presence of rare higher-order junctions with 4 or more helices. Compact branching arises from a preponderance of base pairing between nucleotides close to each other in the primary sequence. The density of branching represents a degree of freedom optimized by viral RNA genomes in response to the evolutionary pressure to be packaged reliably. Several families of viruses are analyzed to delineate the effects of capsid geometry, size and charge stabilization on the selective pressure for RNA compactness. Compact branching has important implications for RNA folding and viral assembly.

  18. What Lies Below a Martian Ice Cap

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for larger annotated version This image (top) taken by the Shallow Radar instrument on NASA's Mars Reconnaissance Orbiter reveals the layers of ice, sand and dust that make up the north polar ice cap on Mars. It is the most detailed look to date at the insides of this ice cap. The colored map below the radar picture shows the topography of the corresponding Martian terrain (red and white represent higher ground, and green and yellow lower). The radar image reveals four never-before-seen thick layers of ice and dust separated by layers of nearly pure ice. According to scientists, these thick ice-free layers represent approximately one-million-year-long cycles of climate change on Mars caused by variations in the planet's tilted axis and its eccentric orbit around the sun. Adding up the entire stack of ice gives an estimated age for the north polar ice cap of about 4 million years a finding that agrees with previous theoretical estimates. The ice cap is about 2 kilometers (1.2 miles) thick. The radar picture also shows that the boundary between the ice layers and the surface of Mars underneath is relatively flat (bottom white line on the right). This implies that the surface of Mars is not sagging, or bending, under the weight of the ice cap and this, in turn, suggests that the planet's lithosphere, a combination of the crust and the strong parts of the upper mantle, is thicker than previously thought. A thicker lithosphere on Mars means that temperatures increase more gradually with depth toward the interior. Temperatures warm enough for water to be liquid are therefore deeper than previously thought. Likewise, if liquid water does exist in aquifers below the surface of Mars, and if there are any organisms living in that water, they would have to be located deeper in the planet. The topography data are from Mars Orbiter Laser Altimeter, which was flown on NASA's Mars Global Surveyor mission. NPLD stands

  19. Ten-year results from the long-term soil productivity study in aspen ecosystems of the northern Great Lakes region

    OpenAIRE

    Voldseth, Richard; Palik, Brian; Elioff, John

    2011-01-01

    Impacts of organic matter removal and compaction on soil physical and chemical properties and forest productivity are reported from the first 10 years of the Long-Term Soil Productivity Study in Great Lakes aspen ecosystems. Organic matter removal treatments included main bole, total tree harvest, and total tree harvest with forest floor removal. Compaction treatments included no compaction beyond normal levels from harvest, moderate compaction, and heavy compaction. Main bole harvest with...

  20. Impact of wheeled and tracked tractors on soil physical properties in a mixed conifer stand

    OpenAIRE

    Cambi M.; Certini G; Fabiano F; Foderi C; Laschi A; Picchio R

    2015-01-01

    Damage to forest soil caused by vehicle traffic mainly consists of soil compaction, displacement, and rut formation. Severity of the damage depends on vehicle mass, weight of the carried loads, ground morphology, and soil properties, such as moisture. This paper investigates the impacts of two types of vehicles (tracked or wheeled tractor), traffic intensities (one or five skidding cycles) and soil moisture (24% or 13% by weight) on compaction of a loam textured soil in a mixed conifer stand ...

  1. Characterization of cap binding proteins associated with the nucleus

    International Nuclear Information System (INIS)

    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-(32P)-(4-(benzoyl-phenyl)methylamido)-7-methylguanosine-5'-triphosphate (BP-m7GTP). 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-m7GTP 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 m7GTP-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)

  2. The United Nations Global Compact

    DEFF Research Database (Denmark)

    Rasche, Andreas; Waddock, Sandra; McIntosh, Malcolm

    2013-01-01

    This article reviews the interdisciplinary literature on the UN Global Compact. The review identifies three research perspectives, which scholars have used to study the UN Global Compact so far: a historical perspective discussing the Global Compact in the context of UN-business relations......, an operational perspective discussing the composition and impact of its participants, as well as a governance perspective discussing the constraints and opportunities of the initiative as an institutionalized arena for addressing global governance gaps. The authors contrast these three perspectives and identify...... key empirical as well as conceptual scholarly contributions. The remainder of this article contains focused summaries of the articles selected for this Special Issue. All articles are introduced and evaluated against the background of the three research perspectives....

  3. DEVELOPMENT OF RHEOLOGY OF ROAD-BUILDING MATERIALS FOR PERFECTION OF THEIR COMPACTION TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Vl. P. Podolskу

    2012-04-01

    Full Text Available Problem statement. The main problems of improving the quality and effectiveness of compaction of soil subgrade and road asphalt mixtures are discussed. Technology of road-building materials compaction can be improved by developing and using the rheological approach in the describing and studying changes in physical and mechanical parameters of materials, when the rheological properties of compacted material is closely connected to the nature of a force action applied to it.Results. The principles of designing rheological models of soil subgrade and road asphalt mixtures are formulated, based on which a model is suggested of the creep process of road construction materials using the theory of hereditary creep of elastic-visco-plastic materials. The choice of exponential and power influence functions is explained, the application of which will improve the accuracy of the physical and mechanical properties of compacted materials. Conclusions. Development of rheology road soils and asphalt mixtures reveals significant new laws in the development of deformation of compacted layers of road construction materials in the way of improving the compaction technology.

  4. THE EFFECT OF STORAGE AT AMBIENT HUMIDITY ON THE BET-SPECIFIC SURFACE-AREA OF TABLETS COMPACTED FROM DIFFERENT MATERIALS

    NARCIS (Netherlands)

    RIEPMA, KA; DEKKER, BG; JAGER, RS; ELBERSE, PA; LERK, CF

    1993-01-01

    Tablets compacted from both water soluble and water insoluble particulate solids showed no change in BET-specific surface area when transferred immediately after ejection from the die in a dry atmosphere. Storage at ambient humidity resulted in an irreversible decrease in surface area, caused by cap

  5. The Planck Compact Source Catalogues

    OpenAIRE

    Lopez-Caniego, Marcos

    2015-01-01

    The Second Planck Catalogue of Compact Sources is a catalogue of sources observed over the entire sky at nine different frequencies between 30 and 857 GHz. It consists of Galactic and extragalactic objects detected in the Planck single-frequency full mission total intensity maps. Compact sources detected in the lower frequency channels are assigned to the PCCS2, while at higher frequencies they are assigned to one of two sub·catalogues, the PCCS2 or PCCS2E, depending on their location ...

  6. Professional Windows Embedded Compact 7

    CERN Document Server

    Phung, Samuel; Joubert, Thierry; Hall, Mike

    2011-01-01

    Learn to program an array of customized devices and solutions As a compact, highly efficient, scalable operating system, Windows Embedded Compact 7 (WEC7) is one of the best options for developing a new generation of network-enabled, media-rich, and service-oriented devices. This in-depth resource takes you through the benefits and capabilities of WEC7 so that you can start using this performance development platform today. Divided into several major sections, the book begins with an introduction and then moves on to coverage of OS design, application development, advanced application developm

  7. Evaluación de la compactación de suelos en siembra directa en la Llanura Chacopampeana de la provincia de Tucumán, R. Argentina Evaluation of soil compaction under no tillage systems in the Chacopampeana Plain in Tucumán, Argentina

    Directory of Open Access Journals (Sweden)

    G. Agustín Sanzano

    2012-06-01

    para decidir el uso de descompactadores de suelo.No-tilled soils can cause topsoil compaction as a result of the lack of soil removal and of machinery traffic. Using subsoilers can reduce this effect. This study was carried out in grain fields located at four sites in the Chacopampeana Plain, province of Tucumán, Argentina. Five no-tillage soil management situations were evaluated in terms of soil compaction degree and other related soil physical properties. These situations were: 'new soils', under no tillage management for less than five years (N; more than 10 years under no tillage management, continuously planted with soybean (SS; more than 10 years under no tillage management and soybean/corn rotation (SM; more than 10 years under no tillage management, with deep vertical tillage prior to sowing, and continuously planted with soybean (SS + LVP; and soils of more than 10 years under no tillage management, soybean/corn rotation, and deep vertical tillage before sowing (SM + LVP. Parameters evaluated before sowing were: bulk density (Dap, maximum bulk density (Dap max, relative apparent density, penetration resistance (RP, crop residue, infiltration rate (I, and organic matter (OM. In topsoil, OM was significantly higher in N than in SS and SS + LVP, while SM and SM + LVP showed intermediate values. LVP showed significantly lower crop residues than those without LPV. In turn, SM had higher crop residues than SS. Upper 20 cm Dap was higher in all situations without LVP, except in N. In most situations, relative apparent density did not exceed 90%, considered critical for normal soybean root growth. RP was significantly lower in SS + LPV and SM + LVP than in SS and SM, respectively. Infiltration rates (I were significantly higher in LPV than in those situations without tillage. However, N had the highest I, probably due to soil porous system conservation. It is advisable to quantify all these parameters before deciding to use deep tillage equipments.

  8. Effet de la combinaison de la chaux et de la pouzzolane naturelle sur le compactage et la résistance des sols mous argileux Effect of the combination of lime and natural pozzolana on the compaction and strength of soft clayey soils

    Directory of Open Access Journals (Sweden)

    Kenai S.

    2012-09-01

    limenatural pozzolana were added to soft soils at the same ranges. Test specimens were subjected to compaction tests and unconfined compression tests. Specimens were cured for 1, 7, 28 and 90 days after which they were tested for unconfined compression tests. Based on the favourable results obtained, it can be concluded that the soft soils can be successfully stabilized by the combined action of lime and natural pozzolana. Since natural pozzolana is much cheaper than lime, the addition of natural pozzolana in limesoil mix may particularly become attractive and can result in cost reduction of construction.

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

    International Nuclear Information System (INIS)

    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

  10. Soil weight (lbf/ft{sup 3}) at Hanford waste storage locations (2 volumes)

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. GPS/CAPS dual-mode software receiver

    Institute of Scientific and Technical Information of China (English)

    NING ChunLin; SHI HuLi; HU Chao

    2009-01-01

    The positioning of the GPS or Chinese Area Positioning System (CAPS) software receiver was developed on a software receiver platform.The structure of the GPSlCAPS dual-mode software receiver was put forward after analyzing the differences in the satellite identification,ranging code,spread spectrum,coordinate system,time system,carrier band,and navigation data between GPS and CAPS.Based on Matlab software on a personal computer,baseband signal processing and positioning procedures were completed using real GPS and CAPS radio frequency signals received by two antennas.Three kinds of experiments including GPS positioning,CAPS positioning,and GPS/CAPS positioning were carried out.Stability and precision of the results were analyzed and compared.The experimental results show that the precision of CAPS is similar to that of GPS,while the positioning precision of the GPS/CAPS dual-mode software receiver is 1-2 m higher than that of CAPS or GPS.The smallest average variance of the positioning can be obtained by using the GPS/CAPS dual-mode software receiver.

  12. GPS/CAPS dual-mode software receiver

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The positioning of the GPS or Chinese Area Positioning System (CAPS) software receiver was developed on a software receiver platform. The structure of the GPS/CAPS dual-mode software receiver was put forward after analyzing the differences in the satellite identification, ranging code, spread spectrum, coordinate system, time system, carrier band, and navigation data between GPS and CAPS. Based on Matlab software on a personal computer, baseband signal processing and positioning procedures were completed using real GPS and CAPS radio frequency signals received by two antennas. Three kinds of experiments including GPS positioning, CAPS positioning, and GPS/CAPS positioning were carried out. Stability and precision of the results were analyzed and compared. The experimental results show that the precision of CAPS is similar to that of GPS, while the positioning precision of the GPS/CAPS dual-mode software receiver is 1-2 m higher than that of CAPS or GPS. The smallest average variance of the positioning can be obtained by using the GPS/CAPS dual-mode software receiver.

  13. Quantifying Solar Wind-Polar Cap Interactions

    Science.gov (United States)

    Urban, K. D.; Gerrard, A. J.; Lanzerotti, L. J.; Weatherwax, A. T.; Huang, Y.

    2015-12-01

    It is well known that the solar wind is a major driver of ultra-low frequency [ULF] power at ground locations from low to high latitudes. However, due to the scarcity of deep polar cap magnetometer sites, it is not clear when, where, or if this is true deep inside the polar cap on open field lines where interplanetary magnetic field [IMF] ULF waves could possibly be directly detected. Given recent observations of very large Joule heating estimates from DMSP data, together with the large heating reported by the CHAMP satellite, it is important to understand the degree to which ULF waves in the solar wind can directly cause such heating. Using a time series of lagged correlation sequences ("dynamic correlograms") between GSM Bz ULF power (computed via data obtained from NASA's Advanced Composition Explorer [ACE] ahead of Earth in the solar wind) and the horizontal ULF power (H^2=N^2+E^2) from ground-based magnetometers in Earth's southern polar cap, we investigate the direct penetration of ULF waves from the solar wind into the polar ionosphere during a gamut of space weather conditions at a distributed network of Automated Geophysical Observatories [AGOs] in Antarctica. To infer causation, a predicted lag correlation maximum at each time step is computed by simply dividing the associated distance of ACE from Earth by the concurrent bulk solar wind speed. This technique helps parse out direct penetration of solar wind ULF waves from other sources (e.g., via leakage from closed field line resonances due to the bulk solar wind plasma viscously interacting at dawn/dusk flanks inducing Kelvin-Helmholtz instabilities [KHI] or compressional modes induced by impulses in solar wind dynamic pressure). The identified direct-penetrating ULF waves are related to the DMSP-derived Poynting fluxes by regression analysis, and conclusions are drawn for the importance of the ULF source for the measured heating.

  14. STRUCTURAL RECOVERY AND PRODUCTION OF TIFTON 85 GRASS IN COMPACTED RED-YELLOW ARGISOL RECUPERAÇÃO ESTRUTURAL E PRODUÇÃO DE CAPIM-TIFTON 85 EM UM ARGISSOLO VERMELHO-AMARELO COMPACTADO

    OpenAIRE

    Kátia Aparecida de Pinho Costa; Eduardo da Costa Severiano; Geraldo César de Oliveira; Eduardo Nunes Magalhães; Matheus Bornelli de Castro

    2009-01-01

    The soil compaction promoted for animal trampling and traffic of machines, is one of great impediments to attainment of raised pasture productivities. However, the soil-pasture relationship studies have not taken in consideration the biological soil descompaction, as well as its effect in productivity. This study objective was to evaluate dry mass production of Tifton 85 grass in function of different soil compaction degrees and potential of structural quality recovery of an Red-Yellow Argiso...

  15. JACKSON'S THEOREM FOR COMPACT GROUPS

    Institute of Scientific and Technical Information of China (English)

    H. Vaezi; S. F. Rzaev

    2002-01-01

    In this article we consider the generalized shift operator defined by(Sh.f)(g) = ∫Gf (tut-1g)dton compact group G and by help of this operator we define "Spherical" modulus of continuity. So we proveStechkin and Jackson type theorems.

  16. DNA compaction by nonbinding macromolecules

    NARCIS (Netherlands)

    Vries, de R.J.

    2012-01-01

    Compaction of DNA by nonbinding macromolecules such as uncharged flexible polymer chains and negatively charged globular proteins is thought to have various applications in biophysics, for example in the formation of a nucleoid structure in bacteria. A simple experimental model that has been very we

  17. Interpolation of compact non-linear operators

    OpenAIRE

    Bento AJG

    2000-01-01

    Let and be two Banach couples and let be a continuous map such that is a Lipschitz compact operator and is a Lipschitz operator. We prove that if is also compact or is continuously embedded in or is continuously embedded in , then is also a compact operator when and . We also investigate the behaviour of the measure of non-compactness under real interpolation and obtain best possible compactness results of Lions–Peetre type for non-linear operators. A two-sided compactness r...

  18. Towards an improved understanding of strength and anisotropy of cold compacted powder

    Science.gov (United States)

    Wang, Wenhai

    The strength of powder compacts after cold compaction is known to be anisotropic, which comes from the directionality of microstructure resulting from initial particle morphology and/or from particle deformation during compaction. Current work focuses on multi-scale numerical analysis of powder compaction with emphasis on the role of interparticle cohesion on post-compaction mechanical properties. At macroscopic level, we applied phenomenological model to describe the mechanical behavior of powder, in which the material is considered to be continuum medium. A user subroutine (VUMAT) was successfully developed for ABAQUS/Explicit analysis, in which one of the popular phenomenological models for powder compaction---Drucker Prager/Cap model---is implemented. By studying of pharmaceutical powder die compaction and subsequent diametrical compression test via finite element analysis, the capabilities and limitations of current constitutive models are evaluated on predicting such as density, stress and tool force evolution, as well as the strength and fracture tendency. Our results illustrate that current model has good predictive capability of powder densification (e.g. density evolution) but can not predict post-compaction strength well. The following studies focus on evaluating the physics and mechanics occurring at particle level. The compaction of granular media was explored by using MPFEM approach. In the new model, individual particles discretized with a finite element mesh allow for a full description of contact mechanics and local and global particle kinematics. The introduction of a layer of degrading material on the surface of each particle provides the means of introducing variable cohesion and its effect on the final strength of compacts. The simulations show that the unloading creates tensile stresses at the root of the contact necks, which may cause partial or full separation of contact interface when the cohesion developed during loading is not strong

  19. Modified swelling pressure apparatus using vapor pressure technique for compacted bentonite

    International Nuclear Information System (INIS)

    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

  20. Permeability response of oil-contaminated compacted clays

    International Nuclear Information System (INIS)

    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

  1. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  2. Performance of paper mill sludges as landfill capping material

    Energy Technology Data Exchange (ETDEWEB)

    Moo-Young, H.K. Jr. [Lehigh Univ., Bethlehem, PA (United States); Zimmie, T.F. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-12-31

    The high cost of waste containment has sparked interest in low cost and effective strategies of containing wastes. Paper mill sludges have been effectively used as the impermeable barrier in landfill covers. Since paper mill sludges are viewed as a waste material, the sludge is given to the landfill owner at little or no cost. Thus, when a clay soil is not locally available to use as the impermeable barrier in a cover system, paper sludge barriers can save $20,000 to $50,000 per acre in construction costs. This study looks at the utilization and performance of blended and primary paper sludge as landfill capping material. To determine the effectiveness of paper sludge as an impermeable barrier layer, test pads were constructed to simulate a typical landfill cover with paper sludge and clay as the impermeable barrier and were monitored for infiltration rates for five years. Long-term hydraulic conductivity values estimated from the leachate generation rates of the test pads indicate that paper sludge provides an acceptable hydraulic barrier.

  3. 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.

  4. 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.

  5. MFTF-. cap alpha. + T progress report

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W.D. (ed.)

    1985-04-01

    Early in FY 1983, several upgrades of the Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory (LLNL) were proposed to the fusion community. The one most favorably received was designated MFTF-..cap alpha..+T. The engineering design of this device, guided by LLNL, has been a principal activity of the Fusion Engineering Design Center during FY 1983. This interim progress report represents a snapshot of the device design, which was begun in FY 1983 and will continue for several years. The report is organized as a complete design description. Because it is an interim report, some parts are incomplete; they will be supplied as the design study proceeds. As described in this report, MFTF-..cap alpha..+T uses existing facilities, many MFTF-B components, and a number of innovations to improve on the physics parameters of MFTF-B. It burns deuterium-tritium and has a central-cell Q of 2, a wall loading GAMMA/sub n/ of 2 MW/m/sup 2/ (with a central-cell insert module), and an availability of 10%. The machine is fully shielded, allows hands-on maintenance of components outside the vacuum vessel 24 h after shutdown, and has provisions for repair of all operating components.

  6. Selection of satellite constellation framework of CAPS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the idea of transmitting the satellite navigation and positioning system, taking the distribution and variation of the Position Dilution of Precision factor (PDOP), which is closely related with the precision of navigation and positioning, within the China area as the primary criterion, we analyze and discuss the tentative plan of constellation configuration consisting of geosynchronous orbit (GEO) communication satellites and inclined geosynchronous orbit (IGSO) satellites for the transmitting Chinese Area Positioning System (CAPS). We emphatically consider the effect on the PDOP by the three major orbit parameters including the inclination, eccentricity and right ascension of the ascend- ing node (RAAN) of IGSO satellites, to research the strategies of the constellation configuration of CAPS through software emulation. Various constellation configurations are analyzed and compared and the results show that the constellation configuration, consisting of three IGSO communication satellites in three orbits with the same inclination as 50°, the difference in RAAN as 120° and the same "8" shaped ground track centered near 115°E and four or five GEO communication satellites within 60°E to 150°E, can satisfy the requirement that Chinese domain is availably covered and the navigation and positioning with high precision could be obtained. Three relatively excellent constellation configurations are initially suggested and some concerned issues are discussed in this work.

  7. Magnetically capped rolled-up nanomembranes.

    Science.gov (United States)

    Streubel, Robert; Thurmer, Dominic J; Makarov, Denys; Kronast, Florian; Kosub, Tobias; Kravchuk, Volodymyr; Sheka, Denis D; Gaididei, Yuri; Schäfer, Rudolf; Schmidt, Oliver G

    2012-08-01

    Modifying the curvature in magnetic nanostructures is a novel and elegant way toward tailoring physical phenomena at the nanoscale, allowing one to overcome limitations apparent in planar counterparts. Here, we address curvature-driven changes of static magnetic properties in cylindrically curved magnetic segments with different radii of curvature. The curved architectures are prepared by capping nonmagnetic micrometer- and nanometer-sized rolled-up membranes with a soft-magnetic 20 nm thick permalloy (Ni(80)Fe(20)) film. A quantitative comparison between the magnetization reversal processes in caps with different diameters is given. The phase diagrams of magnetic equilibrium domain patterns (diameter versus length) are generated. For this, joint experimental, including X-ray magnetic circular dichroism photoelectron emission microscopy (XMCD-PEEM), and theoretical studies are carried out. The anisotropic magnetostatic interaction in cylindrically curved architectures originating from the thickness gradient reduces substantially the magnetostatic interaction between closely packed curved nanowires. This feature is beneficial for racetrack memory devices, since a much higher areal density might be achieved than possible with planar counterparts.

  8. Comparison of Polar Cap (PC) index calculations.

    Science.gov (United States)

    Stauning, P.

    2012-04-01

    The Polar Cap (PC) index introduced by Troshichev and Andrezen (1985) is derived from polar magnetic variations and is mainly a measure of the intensity of the transpolar ionospheric currents. These currents relate to the polar cap antisunward ionospheric plasma convection driven by the dawn-dusk electric field, which in turn is generated by the interaction of the solar wind with the Earth's magnetosphere. Coefficients to calculate PCN and PCS index values from polar magnetic variations recorded at Thule and Vostok, respectively, have been derived by several different procedures in the past. The first published set of coefficients for Thule was derived by Vennerstrøm, 1991 and is still in use for calculations of PCN index values by DTU Space. Errors in the program used to calculate index values were corrected in 1999 and again in 2001. In 2005 DMI adopted a unified procedure proposed by Troshichev for calculations of the PCN index. Thus there exists 4 different series of PCN index values. Similarly, at AARI three different sets of coefficients have been used to calculate PCS indices in the past. The presentation discusses the principal differences between the various PC index procedures and provides comparisons between index values derived from the same magnetic data sets using the different procedures. Examples from published papers are examined to illustrate the differences.

  9. PANDA EMC backward end-cap mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Capozza, Luigi; Ceballos, Jorge; Lin, Dexu; Maas, Frank; Rodriguez, David; Valente, Roserio; Welzel, Felix [Helmholtz-Institut Mainz (Germany); Collaboration: PANDA-Collaboration

    2013-07-01

    The PANDA experiment at the FAIR facility will be a multipurpose hermetic spectrometer covering the full solid angle range. A key role for several physics cases will be played by the electromagnetic calorimeter. This includes ca. 15000 PbWO{sub 4} scintillating crystals arranged in a central barrel, a forward and a backward end-cap. The backward end-cap of the PANDA electromagnetic calorimeter is composed by 540 straight crystals covering the scattering angles between 147 {sup circle} and 161 {sup circle}. They are housed in the so-called alveoli which are carbon fibre boxes, providing both strength and low material budget. The crystals are to work at -25 C in order to improve the light yield. To achieve this temperature a cooling system and thermal insulation are needed. The cooling system removes the heat coming from the electronics and through walls, cables and mechanical supports. Vacuum insulated panels are installed as a thermal shielding. Avalanche Photodiodes (APD) have been chosen as photon detectors, since they are still functional under strong magnetic fields. ASIC chips will be used to amplify the APD signal, this preamplifier features low noise and low heat generation. Due to the weight of this detector, it will be supported from the outside of the PANDA target spectrometer in a counter lever arm position.

  10. Arrays of magnetic nanoparticles capped with alkylamines

    Indian Academy of Sciences (India)

    P John Thomas; P Saravanan; G U Kulkarni; C N R Rao

    2002-02-01

    Magnetic metal and metal oxide nanoparticles capped with alkylamines have been synthesized and characterized by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray analysis and magnetization measurements. Core-shell Pd–Ni particles with composition, Pd561Ni3000, (diameter ∼ 3.3 nm) are superparamagnetic at 5 K and organize themselves into two-dimensional crystalline arrays. Similar arrays are obtained with Pd561Ni3000Pd1500 nanoparticles containing an additional Pd shell. Magnetic spinel particles of -Fe2O3, Fe3O4 and CoFe2O4 of average diameters in the 4–6 nm range coated with octylamine are all supermagnetic at room temperature and yield close-packed disordered arrays. Relatively regular arrays are formed by dodecylamine-capped Fe3O4 nanoparticles (∼ 8.6 nm diameter) while well-ordered hexagonal arrays were obtained with octylamine-covered Co3O4 nanoparticles (∼ 4.2 nm diameter).

  11. 关于振动法测试碾压混凝土 填筑密实程度的研究%About the research of test roller compacted concrete filling compaction degree by vibration method

    Institute of Scientific and Technical Information of China (English)

    陈志远; 王振振; 陈军琪

    2015-01-01

    文章介绍了一种用振动法测试碾压混凝土填筑密实程度的研究过程和成果,提出了用土体振动参数表征密实程度的观点,对土体振动传播速度、主振频率、振动幅度多种参数与密实度的关系进行了探究,发现了振动频率、振动幅度与土体密实程度之间存在的规律,并以此为基础形成了一种新的碾压混凝土密度程度测试方法,有望在业内得以应用.%This paper introduces the research process and result about testing roller compacted concrete filling compaction degree using vibration method, put forward with the view of characterizing soil dense degree by its parameter, and to explore the relationship between a variety of soil vibration parameters and compactness of soil, including the soil vibration propagation speed, the main vibration frequency, the vibration amplitude etc, and to find the rule between the soil vibration frequency, vibration amplitude and soil compaction degree. On this basis, to form the new testing method for density degree of roller compacted concrete, is expected to application in the industry.

  12. Acoustic Monitoring of the Arctic Ice Cap

    Science.gov (United States)

    Porter, D. L.; Goemmer, S. A.; Chayes, D. N.

    2012-12-01

    Introduction The monitoring of the Arctic Ice Cap is important economically, tactically, and strategically. In the scenario of ice cap retreat, new paths of commerce open, e.g. waterways from Northern Europe to the Far East. Where ship-going commerce is conducted, the U.S. Navy and U.S. Coast Guard have always stood guard and been prepared to assist from acts of nature and of man. It is imperative that in addition to measuring the ice from satellites, e.g. Icesat, that we have an ability to measure the ice extent, its thickness, and roughness. These parameters play an important part in the modeling of the ice and the processes that control its growth or shrinking and its thickness. The proposed system consists of three subsystems. The first subsystem is an acoustic source, the second is an array of geophones and the third is a system to supply energy and transmit the results back to the analysis laboratory. The subsystems are described below. We conclude with a plan on how to tackle this project and the payoff to the ice cap modeler and hence the users, i.e. commerce and defense. System Two historically tested methods to generate a large amplitude multi-frequency sound source include explosives and air guns. A new method developed and tested by the University of Texas, ARL is a combustive Sound Source [Wilson, et al., 1995]. The combustive sound source is a submerged combustion chamber that is filled with the byproducts of the electrolysis of sea water, i.e. Hydrogen and Oxygen, an explosive mixture which is ignited via a spark. Thus, no additional compressors, gases, or explosives need to be transported to the Arctic to generate an acoustic pulse capable of the sediment and the ice. The second subsystem would be geophones capable of listening in the O(10 Hz) range and transmitting that data back to the laboratory. Thus two single arrays of geophones arranged orthogonal to each other with a range of 1000's of kilometers and a combustive sound source where the two

  13. Warm compaction powder metallurgy of Cu

    Institute of Scientific and Technical Information of China (English)

    NGAI Tungwai Leo; WANG Shang-lin; LI Yuan-yuan; ZHOU Zho-yao; CHEN Wei-ping

    2005-01-01

    A series of experiments were carried out using different admixed lubricant contents,different compaction pressures and temperatures in order to study the warm compaction of copper powder.Results show that too much admixed lubricant will lead to the squeeze out of the lubricant from the compact during the warm compaction processing of Cu powder.Results also show that blisters can be found in sintered samples that contain lubricant less than 0.15% (mass fraction).Optimal warm compaction parameters for producing high density powder metallurgy copper material are obtained.Compacts with green density of 8.6 g/cm3 and a sintered density of 8.83 g/cm3 can be produced by warm compacting the Cu powder,which contains 0.2% admixed lubricant,and is compacted at 145 ℃ with a pressure of 700 Mpa.

  14. DEVELOPMENT OF BIOAVAILABILITY AND BIOKINETICS DETERMINATION METHODS FOR ORGANIC POLLUTANTS IN SOIL TO ENHANCE IN-SITU AND ON-SITE BIOREMEDIATION

    Science.gov (United States)

    Determination of biodegradation rates of organics in soil slurry and compacted soil systems is essential for evaluating the efficacy of bioremediation for treatment of contaminated soils. In this paper, a systematic protocol has been developed for evaluating bioknetic and transp...

  15. Mass loss of Greenland's glaciers and ice caps 2003-2008 revealed from ICESat laser altimetry data

    OpenAIRE

    T. Bolch; L. Sandberg Sørensen; Simonsen, S.B.; Mölg, N.; Machguth, H.; Rastner, P.; Paul, F.

    2013-01-01

    The recently finalized inventory of Greenland's glaciers and ice caps (GIC) allows for the first time to determine the mass changes of the GIC separately from the ice sheet using space-borne laser altimetry data. Corrections for firn compaction and density that are based on climatic conditions are applied for the conversion from volume to mass changes. The GIC which are clearly separable from the icesheet (i.e., have a distinct ice divide or no connection) lost 27.9 ± 10.7 Gt a-1 or 0.08 ± 0....

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

    International Nuclear Information System (INIS)

    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)

  17. Analysis list: Cap-H2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Cap-H2 Cell line + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Cap-H2....1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Cap-H2.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Ca...p-H2.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Cap-H2.Cell_line.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Cell_line.gml ...

  18. Design and Performance of Capping Layers for EUV Multilayer Mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Bajt, S; Chapman, H N; Nuygen, N; Alameda, J; Robinson, J C; Malinowski, M; Gullikson, E; Aquila, A; Tarrio, C; Grantham, S

    2003-03-10

    The reflectance stability of multilayer coatings for extreme ultraviolet lithography (EUVL) in a commercial tool environment is of uttermost importance to ensure continuous exposures with minimum maintenance cost. We have made substantial progress in designing the protective capping layer coatings, understanding their performance and estimating their lifetimes based on accelerated electron beam and EUV exposure studies. Our current capping layer coatings have about 40 times longer lifetimes than Si-capped multilayer optics. Nevertheless, the lifetime of current Ru-capped multilayers is too short to satisfy commercial tool requirements and further improvements are essential.

  19. Analyses of Current And Wave Forces on Velocity Caps

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Buhrkall, Jeppe; Eskesen, Mark C. D.;

    2015-01-01

    Velocity caps are often used in connection with for instance offshore intake sea water for the use of for cooling water for power plants or as a source for desalinization plants. The intakes can also be used for river intakes. The velocity cap is placed on top of a vertical pipe. The vertical pipe......) this paper investigates the current and wave forces on the velocity cap and the vertical cylinder. The Morison’s force model was used in the analyses of the extracted force time series in from the CFD model. Further the distribution of the inlet velocities around the velocity cap was also analyzed in detail...

  20. Effect of swim cap model on passive drag.

    Science.gov (United States)

    Gatta, Giorgio; Zamparo, Paola; Cortesi, Matteo

    2013-10-01

    Hydrodynamics plays an important role in swimming because even small decreases in a swimmer's drag can lead to performance improvements. During the gliding phases of a race, the head of a swimmer is an important point of impact with the fluid, and the swim cap, even if it covers only a small portion of the swimmer's body, can have an influence on drag. The purpose of this study was to investigate the effects on passive drag (Dp) of wearing 3 different types of swim caps (LSC: a lycra cap; CSC: a silicone cap; HSC: a silicone helmet cap without seams). Sixteen swimmers were tested at 3 velocities (1.5, 1.7, 1.9 m·s), and the Dp measurements were repeated at each condition 5 times. A statistical analysis revealed significant differences in drag (p swim cap is the most rigid, the most adherent to the swimmer's head, and does not allow the formation of wrinkles compared with the other 2 investigated swim caps. Therefore, the following conclusions can be made: (a) swimmers should take care when selecting their swim cap if they want to improve the fluid dynamics at the "leading edge" of their body and (b) because Dp is affected by the swim cap model, care should be taken when comparing data from different studies, especially at faster investigated speeds.

  1. Powder compaction in systems of bimodal distribution

    Science.gov (United States)

    Chattopadhyay, A. K.; Whittemore, O. J., Jr.

    1973-01-01

    The compaction of mixtures involving different particle sizes is discussed. The various stages of the compaction process include the rearrangement of particles, the filling of the interstices of the large particles by the smaller ones, and the change in particle size and shape upon further densification through the application of pressure. Experimental approaches and equipment used for compacting material are discussed together with the theoretical relations of the compacting process.

  2. The Influence of Urban Soil Rehabilitation on Soil Carbon Dynamics, Greenhouse Gas Emission, and Stormwater Mitigation

    OpenAIRE

    Chen, Yujuan

    2013-01-01

    Global urbanization has resulted in rapidly increased urban land. Soils are the foundation that supports plant growth and human activities in urban areas. Furthermore, urban soils have potential to provide a carbon sink to mitigate greenhouse gas emission and climate change. However, typical urban land development practices including vegetation clearing, topsoil removal, stockpiling, compaction, grading and building result in degraded soils. In this work, we evaluated an urban soil rehabilita...

  3. Equationally Compact Acts : Coproducts / Peeter Normak

    Index Scriptorium Estoniae

    Normak, Peeter

    1998-01-01

    In this article equational compactness of acts and its generalizations are discussed. As equational compactness does not carry over to coproducts a slight generalization of c-equational campactness is introduced. It is proved that a coproduct of acts is c-equationally compact if and only if all components are c-equationally campact

  4. The Kolmogorov-Riesz compactness theorem

    CERN Document Server

    Hanche-Olsen, Harald

    2009-01-01

    We show that the Arzela-Ascoli theorem and Kolmogorov compactness theorem both are consequences of a simple lemma on compactness in metric spaces. Their relation to Helly's theorem is discussed. The paper contains a detailed discussion on the historical background of the Kolmogorov compactness theorem.

  5. Effect of compaction on microbial activity and carbon and nitrogen transformations in two oxisols with different mineralogy

    Directory of Open Access Journals (Sweden)

    Sérgio Ricardo Silva

    2011-08-01

    Full Text Available The use of machinery in agricultural and forest management activities frequently increases soil compaction, resulting in greater soil density and microporosity, which in turn reduces hydraulic conductivity and O2 and CO2 diffusion rates, among other negative effects. Thus, soil compaction has the potential to affect soil microbial activity and the processes involved in organic matter decomposition and nutrient cycling. This study was carried out under controlled conditions to evaluate the effect of soil compaction on microbial activity and carbon (C and nitrogen (N mineralization. Two Oxisols with different mineralogy were utilized: a clayey oxidic-gibbsitic Typic Acrustox and a clayey kaolinitic Xantic Haplustox (Latossolo Vermelho-Amarelo ácrico - LVA, and Latossolo Amarelo distrófico - LA, respectively, in the Brazil Soil Classification System. Eight treatments (compaction levels were assessed for each soil type in a complete block design, with six repetitions. The experimental unit consisted of PVC rings (height 6 cm, internal diameter 4.55 cm, volume 97.6 cm³. The PVC rings were filled with enough soil mass to reach a final density of 1.05 and 1.10 kg dm-3, respectively, in the LVA and LA. Then the soil samples were wetted (0.20 kg kg-1 = 80 % of field capacity and compacted by a hydraulic press at pressures of 0, 60, 120, 240, 360, 540, 720 and 900 kPa. After soil compression the new bulk density was calculated according to the new volume occupied by the soil. Subsequently each PVC ring was placed within a 1 L plastic pot which was then tightly closed. The soils were incubated under aerobic conditions for 35 days and the basal respiration rate (CO2-C production was estimated in the last two weeks. After the incubation period, the following soil chemical and microbiological properties were detremined: soil microbial biomass C (C MIC, total soil organic C (TOC, total N, and mineral N (NH4+-N and NO3--N. After that, mineral N, organic N

  6. Remnants of compact binary mergers

    CERN Document Server

    Domainko, W

    2006-01-01

    We investigate the long-term evolution and observability of remnants originating from the merger of compact binary systems and discuss the differences to supernova remnants. Compact binary mergers expel much smaller amounts of mass at much higher velocities, as compared to supernovae, which will affect the dynamical evolution of their remnants. The ejecta of mergers consist of very neutron rich nuclei. Some of these neutron rich nuclei will produce observational signatures in form of gamma ray lines during their decay. The composition of the ejecta might even give interesting constraints about the internal structure of the neutron star. We further discuss the possibility that merger remnants appear as recently discovered 'dark accelerators' which are extended TeV sources which lack emission in other bands.

  7. Compact heat exchangers modeling: Condensation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Cascales, J.R.; Vera-Garcia, F. [Technical University of Cartagena, Thermal and Fluid Engineering Department, C/Dr. Fleming, s/n 30202 Cartagena, Murcia (Spain); Gonzalvez-Macia, J.; Corberan-Salvador, J.M. [Technical University of Valencia, Applied Thermodynamic Department, Valencia (Spain); Johnson, M.W.; Kohler, G.T. [Modine Manufacturing Company, Commercial Products Group, Racine, WI (United States)

    2010-01-15

    A model for the analysis of compact heat exchangers working as either evaporators or condensers is presented. This paper will focus exclusively on condensation modeling. The model is based on cell discretization of the heat exchanger in such a way that cells are analyzed following the path imposed by the refrigerant flowing through the tubes. It has been implemented in a robust code developed for assisting with the design of compact heat exchangers and refrigeration systems. These heat exchangers consist of serpentine fins that are brazed to multi-port tubes with internal microchannels. This paper also investigates a number of correlations used for the calculation of the refrigerant side heat transfer coefficient. They are evaluated comparing the predicted data with the experimental data. The working fluids used in the experiments are R134a and R410A, and the secondary fluid is air. The experimental facility is briefly described and some conclusions are finally drawn. (author)

  8. Use of Trichoderma spp.on soil microbiology improvement for organic agriculture in Costa Rica

    Institute of Scientific and Technical Information of China (English)

    Miguel Obregón-Gómez

    2004-01-01

    @@ The soil is a complex system where processes have direct influence on crop nutrition and plant health.Unfortunately, most of the agricultural soil management practices, compact them producing poor oxygenation, low benefic microorganism populations and metabolic disorders in plants.

  9. Multipole structure of compact objects

    CERN Document Server

    Quevedo, Hernando

    2016-01-01

    We analyze the applications of general relativity in relativistic astrophysics in order to solve the problem of describing the geometric and physical properties of the interior and exterior gravitational and electromagnetic fields of compact objects. We focus on the interpretation of exact solutions of Einstein's equations in terms of their multipole moments structure. In view of the lack of physical interior solutions, we propose an alternative approach in which higher multipoles should be taken into account.

  10. Flexible Profile Compact Thermal Models

    OpenAIRE

    Sabry, M.-N.

    2005-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920) International audience Recent advances in Compact Thermal Models (CTM) have led to the emergence of a new concept allowing models to be created at any desired order of accuracy. In this paper, the concept will first be generalized to 3D parallelepiped boxes with both surface and/or volumetric heating. The second achievement is an adequate handling of heat transfer through side walls based on an ...

  11. Compact differences of composition operators

    CERN Document Server

    Heller, Katherine; Weir, Rachel J

    2010-01-01

    When $\\varphi$ and $\\psi$ are linear-fractional self-maps of the unit ball $B_N$ in ${\\mathbb C}^N$, $N\\geq 1$, we show that the difference $C_{\\varphi}-C_{\\psi}$ cannot be non-trivially compact on either the Hardy space $H^2(B_N)$ or any weighted Bergman space $A^2_{\\alpha}(B_N)$. Our arguments emphasize geometrical properties of the inducing maps $\\varphi$ and $\\psi$.

  12. Compact planar microwave blocking filters

    Science.gov (United States)

    U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor)

    2012-01-01

    A compact planar microwave blocking filter includes a dielectric substrate and a plurality of filter unit elements disposed on the substrate. The filter unit elements are interconnected in a symmetrical series cascade with filter unit elements being organized in the series based on physical size. In the filter, a first filter unit element of the plurality of filter unit elements includes a low impedance open-ended line configured to reduce the shunt capacitance of the filter.

  13. Weak compactness of biharmonic maps

    Directory of Open Access Journals (Sweden)

    Shenzhou Zheng

    2012-10-01

    Full Text Available This article shows that if a sequence of weak solutions of a perturbed biharmonic map satisfies $Phi_ko 0$ in $(W^{2,2}^*$ and $u_kightharpoonup u$ weakly in $W^{2,2}$, then $u$ is a biharmonic map. In particular, we show that the space of biharmonic maps is sequentially compact under the weak-$W^{2,2}$ topology.

  14. Compact, Polyvalent Mannose Quantum Dots as Sensitive, Ratiometric FRET Probes for Multivalent Protein-Ligand Interactions.

    Science.gov (United States)

    Guo, Yuan; Sakonsinsiri, Chadamas; Nehlmeier, Inga; Fascione, Martin A; Zhang, Haiyan; Wang, Weili; Pöhlmann, Stefan; Turnbull, W Bruce; Zhou, Dejian

    2016-04-01

    A highly efficient cap-exchange approach for preparing compact, dense polyvalent mannose-capped quantum dots (QDs) has been developed. The resulting QDs have been successfully used to probe multivalent interactions of HIV/Ebola receptors DC-SIGN and DC-SIGNR (collectively termed as DC-SIGN/R) using a sensitive, ratiometric Förster resonance energy transfer (FRET) assay. The QD probes specifically bind DC-SIGN, but not its closely related receptor DC-SIGNR, which is further confirmed by its specific blocking of DC-SIGN engagement with the Ebola virus glycoprotein. Tuning the QD surface mannose valency reveals that DC-SIGN binds more efficiently to densely packed mannosides. A FRET-based thermodynamic study reveals that the binding is enthalpy-driven. This work establishes QD FRET as a rapid, sensitive technique for probing structure and thermodynamics of multivalent protein-ligand interactions. PMID:26990806

  15. 76 FR 20044 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2011-04-11

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  16. Stabilization of oily sediments for cap closure of a refinery oxidation pond

    Energy Technology Data Exchange (ETDEWEB)

    Schifano, V. [ARCADIUS US Inc., Chelmsford, MA (United States); Fabian, K. [ARCADIUS US Inc., Seattle, WA (United States); Weise, T. [ARCADIUS US Inc., Los Altos, CA (United States)

    2010-07-01

    This paper discussed a remediation project in which over 400,000 m{sup 3} of oily sediments, dredged sediments, and soils were used to construct a cap foundation layer for the closure of a refinery oxidation pond used as a regulated waste disposal unit. A value engineering approach was used to identify alternative design schemes and construction methods for the project. Field cone penetration tests were used to test the sediments after curing under field environmental and stress conditions. The stabilization design for the pond was developed to account for heterogeneities in sediment properties as well as time variability in groundwater fluctuations and weather conditions. A binder was optimized to minimize deficiencies and achieve a low rate of re-testing and subsequent stabilization repairs. Depositional and post-depositional projects including self-weight consolidation and drying during the 2 years preceding the stabilization transformed the diluted slurry of dredged sediments into a layer of stiff semi-dry silty clay. The silty clay was then blended with the oily sediments to form a cap foundation layer of a least 0.6 m thickness. A liner was placed on the cap foundation to minimize infiltration into the waste unit. Over $4 million was saved using the new approach. 17 refs., 2 tabs., 7 figs.

  17. Thixoforming of Stellite Powder Compacts

    Science.gov (United States)

    Hogg, S. C.; Atkinson, H. V.; Kapranos, P.

    2007-04-01

    Thixoforming involves processing metallic alloys in the semi-solid state. The process requires the microstructure to be spheroidal when part-solid and part-liquid i.e. to consist of solid spheroids surrounded by liquid. The aim of this work was to investigate whether powder compacts can be used as feedstock for thixoforming and whether the consolidating pressure in the thixoformer can be used to remove porosity from the compact. The powder compacts were made from stellite 6 and stellite 21 alloys, cobalt-based alloys widely used for e.g. manufacturing prostheses. Isothermal heat treatments of small samples in the consolidated state showed the optimum thixoforming temperature to be in the range 1340°C-1350°C for both materials. The alloys were thixoformed into graphite dies and flowed easily to fill the die. Porosity in the thixoformed components was lower than in the starting material. Hardness values at various positions along the radius of the thixoformed demonstrator component were above the specification for both alloys.

  18. Strings in compact cosmological spaces

    CERN Document Server

    Craps, Ben; Konechny, Anatoly

    2013-01-01

    We confront the problem of giving a fundamental definition to perturbative string theory in spacetimes with totally compact space (taken to be a torus for simplicity, though the nature of the problem is very general) and non-compact time. Due to backreaction induced by the presence of even a single string quantum, the usual formulation of perturbative string theory in a fixed classical background is infrared-divergent at all subleading orders in the string coupling, and needs to be amended. The problem can be seen as a closed string analogue of D0-brane recoil under an impact by closed strings (a situation displaying extremely similar infrared divergences). Inspired by the collective coordinate treatment of the D0-brane recoil, whereby the translational modes of the D0-brane are introduced as explicit dynamical variables in the path integral, we construct a similar formalism for the case of string-induced gravitational backreaction, in which the spatially uniform modes of the background fields on the compact ...

  19. Compaction Waves in Granular HMX

    Energy Technology Data Exchange (ETDEWEB)

    E. Kober; R. Menikoff

    1999-01-01

    Piston driven compaction waves in granular HMX are simulated with a two-dimensional continuum mechanics code in which individual grains are resolved. The constitutive properties of the grains are modeled with a hydrostatic pressure and a simple elastic-plastic model for the shear stress. Parameters are chosen to correspond to inert HMX. For a tightly packed random grain distribution (with initial porosity of 19%) we varied the piston velocity to obtain weak partly compacted waves and stronger fully compacted waves. The average stress and wave speed are compatible with the porous Hugoniot locus for uni- axial strain. However, the heterogeneities give rise to stress concentrations, which lead to localized plastic flow. For weak waves, plastic deformation is the dominant dissipative mechanism and leads to dispersed waves that spread out in time. In addition to dispersion, the granular heterogeneities give rise to subgrain spatial variation in the thermodynamic variables. The peaks in the temperature fluctuations, known as hot spots, are in the range such that they are the critical factor for initiation sensitivity.

  20. Compact Stellarator Path to DEMO

    Science.gov (United States)

    Lyon, J. F.

    2007-11-01

    Issues for a DEMO reactor are sustaining an ignited/high-Q plasma in steady state, avoiding disruptions and large variations in power flux to the wall, adequate confinement of thermal plasma and alpha-particles, control of a burning plasma, particle and power handling, etc. Compact stellarators have key advantages -- steady-state high-plasma-density operation without external current drive or disruptions, stability without a close conducting wall or active feedback systems, and low recirculating power -- in addition to moderate plasma aspect ratio, good confinement, and high-beta potential. The ARIES-CS study established that compact stellarators can be competitive with tokamaks as reactors. Many of the issues for a compact stellarator DEMO can be answered using results from large tokamaks, ITER D-T experiments and fusion materials, technology and component development programs, in addition to stellarators in operation, under construction or in development. However, a large next-generation stellarator will be needed to address some physics issues: size scaling and confinement at higher parameters, burning plasma issues, and operation with a strongly radiative divertor. Technology issues include simpler coils, structure, and divertor fabrication, and better cost information.

  1. Probability of Occurrence of Soil Disturbances during Timber Harvesting

    OpenAIRE

    2008-01-01

    This paper deals with the probability of occurrence of soil disturbance during timber harvesting operations. Studies were carried out in southern Poland in 26 stands differing in terrain, skidding method, stand age, amount of timber harvested, forest site type, stocking, and soil type. In each stand the occurrence of the following forms of disturbances was measured: soil surface disturbance, soil cover tearing off and soil compaction. Logistic regression models describing the probability of o...

  2. Succession Rules of Various Types of Soil Phosphorus in Larch Plantations

    Institute of Scientific and Technical Information of China (English)

    CHENLixin; JIANGLixue; YANGChengdong

    2004-01-01

    By the method of comparison and analysis, the succession pattern of total P, available phosphorus, organic P types and inorganic P types in rhizosphere and non-rhizosphere soil at different development stages in Larch (Larix olgensis) plantations was revealed. The result showed: when stand age increased, the content of available phosphorus, O-P, total P and organic P in rhizosphere soil decreased greatly or significantly,the content of inorganic P, Ca-P and Fe-P in rhizosphere soil in rhizosphere soil increased greatly or significantly. The content of Ca-P in non-rhizosphere soil increased with stand growing. The content of Fe-P in half-mature stand, available P and Fe-P in near mature stand, available P and Ca-P in mature stand in nonrhizosphere soil was more than that in rhizosphere soil.

  3. Carpentier, la otra novela (cap. IV

    Directory of Open Access Journals (Sweden)

    Urbano Martínez Carmenate

    2014-07-01

    Full Text Available El presente ensayo está extraído de la obra inédita de Urbano Martínez Carmenate, Carpentier, la otra novela (cap. IV. Ofrece una mirada sobre los primeros años de la trayectoria profesional de Alejo Carpentier. Se muestra cómo, durante la década de 1920, se inicia como periodista y cronista teatral. A la vez, comienzan sus conexiones con el Grupo Minorista, que desempeña un papel destacado en la etapa republicana en Cuba. También se contempla su viaje a México en 1926, que constituye su primer contacto directo con la naturaleza y la cultura americanas.

  4. Carpentier, la otra novela (cap. IV

    Directory of Open Access Journals (Sweden)

    Urbano Martínez Carmenate

    2014-06-01

    Full Text Available El presente ensayo está extraído de la obra inédita de Urbano Martínez Carmenate, Carpentier, la otra novela (cap. IV. Ofrece una mirada sobre los primeros años de la trayectoria profesional de Alejo Carpentier. Se muestra cómo, durante la década de 1920, se inicia como periodista y cronista teatral. A la vez, comienzan sus conexiones con el Grupo Minorista, que desempeña un papel destacado en la etapa republicana en Cuba. También se contempla su viaje a México en 1926, que constituye su primer contacto directo con la naturaleza y la cultura americanas.

  5. Motion Analysis of Fiber Band in Compact Field of Compact Spinning

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting angle of suction slot in profile tube, additional twists created by fiber band's rotating around its own axis and ultimate twists in compact yarn are deduced accordingly. The existence of additional twists is also verified through experiments.

  6. 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.

  7. 47 CFR 52.109 - Permanent cap on number reservations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Permanent cap on number reservations. 52.109... (CONTINUED) NUMBERING Toll Free Numbers § 52.109 Permanent cap on number reservations. (a) A Responsible Organization may have in reserve status, at any one time, either 2000 toll free numbers or 7.5 percent of...

  8. 47 CFR 61.41 - Price cap requirements generally.

    Science.gov (United States)

    2010-10-01

    ... party to a merger, acquisition, or similar transaction shall continue to be subject to price cap... no later than one year following the effective date of such merger, acquisition, or similar... subject to price cap regulation, as that term is defined in § 61.3(ee), which are involved in...

  9. ATLAS end-caps 
on the move

    CERN Multimedia

    2007-01-01

    Two delicate and spectacular transport operations have been performed for ATLAS in recent weeks: the first end-cap tracker was installed in its final position, and one of the huge end-caps of the toroid magnet was moved to the top of the experiment’s shaft.

  10. Preparing an ATLAS toroid magnet end-cap for lowering

    CERN Multimedia

    Claudia Marcelloni

    2007-01-01

    One of the two 13-m high toroid magnet end-caps for the ATLAS experiment being transported from the construction hall to the experimental area. The end-cap will be lowered into the ATLAS cavern and attached to an end of the detector.

  11. Regulating Telecommunications : Lessons from U.S. Price Cap Experience

    OpenAIRE

    Jeffrey H. Rohlfs

    1996-01-01

    Price cap regulation uses a formula, set in advance, to determine the price increases for a firm's services for a period of several years. During this period, the firm may keep all the benefits of its incremental productivity gains. Customers can also benefit because the price cap formula may cause prices to rise less rapidly during the period. The sharpened incentives created may encourag...

  12. Temperature Distribution within a Cold Cap during Nuclear Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Derek R.; Schweiger, Michael J.; Riley, Brian J.; Pokorny, Richard; Hrma, Pavel R.

    2015-07-21

    The kinetics of the feed-to-glass conversion affects the waste vitrification rate in an electric melter. The primary area of interest in this conversion process is the cold cap, a layer of reacting feed on top of molten glass. Knowing the temperature profile within a cold cap will help determine its characteristics and relate them to the rate of glass production. The work presented here provides an experimental determination of the temperature distribution within the cold cap. Since a direct measurement of the temperature field within the cold cap is impracticable, an indirect method was developed where the textural features in a laboratory-made cold cap with a high-level waste feed were mapped as a function of position using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. To correlate the temperature distribution to microstructures within the cold cap, microstructures were identified of individual feed samples that were heat treated to set temperatures between 400°C and 1200°C and quenched. The temperature distribution within the cold cap was then established by correlating cold-cap regions with the feed samples of nearly identical structures and was compared with the temperature profile from a mathematical model.

  13. IN SITU REMEDIATION OF CONTAMINATED SEDIMENTS - ACTIVE CAPPING TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Knox, A.; Roberts, J.; Paller, M.; Reible, D.

    2010-09-02

    Active capping is a relatively new approach for treating contaminated sediments. It involves applying chemically reactive amendments to the sediment surface. The main role of active caps is to stabilize contaminants in contaminated sediments, lower the bioavailable pool of contaminants, and reduce the release of contaminants to the water column. Metals are common contaminants in many marine and fresh water environments as a result of industrial and military activities. The mobile, soluble forms of metals are generally considered toxic. Induced chemical precipitation of these metals can shift toxic metals from the aqueous phase to a solid, precipitated phase which is often less bioavailable. This approach can be achieved through application of sequestering agents such as rock phosphates, organoclays, zeolites, clay minerals, and biopolymers (e.g., chitosan) in active capping technology. Active capping holds great potential for a more permanent solution that avoids residual risks resulting from contaminant migration through the cap or breaching of the cap. In addition to identifying superior active capping agents, research is needed to optimize application techniques, application rates, and amendment combinations that maximize sequestration of contaminants. A selected set of active capping treatment technologies has been demonstrated at a few sites, including a field demonstration at the Savannah River Site, Aiken, SC. This demonstration has provided useful information on the effects of sequestering agents on metal immobilization, bioavailability, toxicity, and resistance to mechanical disturbance.

  14. Taxon interactions control the distributions of cryoconite bacteria colonizing a High Arctic ice cap.

    Science.gov (United States)

    Gokul, Jarishma K; Hodson, Andrew J; Saetnan, Eli R; Irvine-Fynn, Tristram D L; Westall, Philippa J; Detheridge, Andrew P; Takeuchi, Nozomu; Bussell, Jennifer; Mur, Luis A J; Edwards, Arwyn

    2016-08-01

    Microbial colonization of glacial ice surfaces incurs feedbacks which affect the melting rate of the ice surface. Ecosystems formed as microbe-mineral aggregates termed cryoconite locally reduce ice surface albedo and represent foci of biodiversity and biogeochemical cycling. Consequently, greater understanding the ecological processes in the formation of functional cryoconite ecosystems upon glacier surfaces is sought. Here, we present the first bacterial biogeography of an ice cap, evaluating the respective roles of dispersal, environmental and biotic filtration occurring at local scales in the assembly of cryoconite microbiota. 16S rRNA gene amplicon semiconductor sequencing of cryoconite colonizing a Svalbard ice cap coupled with digital elevation modelling of physical parameters reveals the bacterial community is dominated by a ubiquitous core of generalist taxa, with evidence for a moderate pairwise distance-decay relationship. While geographic position and melt season duration are prominent among environmental predictors of community structure, the core population of taxa appears highly influential in structuring the bacterial community. Taxon co-occurrence network analysis reveals a highly modular community structured by positive interactions with bottleneck taxa, predominantly Actinobacteria affiliated to isolates from soil humus. In contrast, the filamentous cyanobacterial taxon (assigned to Leptolyngbya/Phormidesmis pristleyi) which dominates the community and binds together granular cryoconite are poorly connected to other taxa. While our study targeted one ice cap, the prominent role of generalist core taxa with close environmental relatives across the global cryosphere indicate discrete roles for cosmopolitan Actinobacteria and Cyanobacteria as respective keystone taxa and ecosystem engineers of cryoconite ecosystems colonizing ice caps. PMID:27261672

  15. Behavior of Pile Group with Elevated Cap Subjected to Cyclic Lateral Loads

    Institute of Scientific and Technical Information of China (English)

    陈云敏; 顾明; 陈仁朋; 孔令刚; 张浙杭; 边学成

    2015-01-01

    The pile group with elevated cap is widely used as foundation of offshore structures such as turbines, power transmission towers and bridge piers, and understanding its behavior under cyclic lateral loads induced by waves, tide water and winds, is of great importance to designing. A large-scale model test on 3×3 pile group with elevated cap subjected to cyclic lateral loads was performed in saturated silts. The preparation and implementation of the test is presented. Steel pipes with the outer diameter of 114 mm, thickness of 4.5 mm, and length of 6 m were employed as model piles. The pile group was cyclic loaded in a multi-stage sequence with the lateral displacement controlled. In addition, a single pile test was also conducted at the same site for comparison. The displacement of the pile cap, the internal forces of individual piles, and the horizontal stiffness of the pile group are presented and discussed in detail. The results indicate that the lateral cyclic loads have a greater impact on pile group than that on a single pile, and give rise to the significant plastic strain in the soil around piles. The lateral loads carried by each row of piles within the group would be redistributed with loading cycles. The lateral stiffness of the pile group decreases gradually with cycles and broadly presents three different degradation patterns in the test. Significant axial forces were measured out in some piles within the group, owing to the strong restraint provided by the cap, and finally lead to a large settlement of the pile group. These findings can be referred for foundation designing of offshore structures.

  16. Progress in LAr EndCap Calorimetry: News from the Hadronic EndCap Group.

    CERN Multimedia

    Oram, C.J.

    With module production and testing completed for the Hadronic EndCap calorimeter, the attention of the HEC group is heavily directed towards wheel assembly in building 180. Three of the four HEC wheels are now assembled and rotated, and work is progressing on assembling the final wheel. This year has been a busy year for the installation of components in the EndCap C cryostat: the signal feedthrough installation was completed April 22nd, the pre-sampler shortly thereafter and the Electro-Magnetic EndCap August 13th. This allowed the HEC group to start transferring the HEC wheels from the T6A storage cradle into the cryostat. The operation started in mid-September and has progressed, on or ahead of schedule, since then with the major milestones being: Insertion of 67 ton front HEC wheel October 3rd Insertion of 90 ton rear HEC wheel October 22nd. The wheel alignment has proved to be excellent, with the position of the centre of the front(rear) wheel with respect to the nominal position being displaced b...

  17. The CAP Theorem Versus Databases with Relaxed ACID properties

    DEFF Research Database (Denmark)

    Frank, Lars; Ulslev Pedersen, Rasmus; Frank, Christian Havnø;

    2014-01-01

    the traditional ACID properties and all the CAP properties were implemented. This optimizing is especially important in mobile integrated databases, where disconnections are normal and frequent. It is also important in distributed databases like EHR (electronic Health Records) where many different hospital...... data from different locations can have at most two of the three desirable CAP properties [5]. The NoSQL movement has applied the CAP theorem as an argument against traditional ACID (atomicity, consistency, isolation, and durability) databases, which prioritize consistency and partition...... availability and sufficient data consistency, despite the presence of network partitions. The overall objective of this paper is to improve the CAP optimization methods by using optimization techniques outside of those preferred in CAP optimization literature. The main contribution is to use relaxed ACID...

  18. Effects of Air-Drying on the Inorganic Phosphorus Forms in Soils

    Institute of Scientific and Technical Information of China (English)

    FENG Ke; TANG Yan; WANG Xiao-li; LU Hai-ming; ZHAO Hai-tao

    2005-01-01

    After 90 day's cultivation of five different plants (rye grass, lupin, buckwheat, rape and amaranth) in three soils (Yellow brown soil, Paddy soil and Red soil), fresh soil samples were collected and inorganic phosphorus (Pi) fractions were measured before and after air-drying. The results clearly indicated that the total Pi and their composition differed significantly among soil types. The air-drying process increased the total Pi in yellow brown soil and in paddy soil, while decreased that in red soil. The total Pi could vary to 70% of that before air-drying. The Pi forms in different soils changed to different extent after air-drying. As to yellow brown soil, Al-P decreased, while O-P and Ca-P increased; as to paddy soil, Al-P and Ca-P increased, while Fe-P and O-P remained; as to red soil, Al-P and Fe-P increased, Ca-P remained and O-P reduced obviously. Growth of different plants in soils had effects on Pi forms during the process of air-drying. Therefore, for chemical study of soil phosphorus, application of fresh soil samples can provide more reliable results.

  19. 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.

  20. The Cooling of Compact Stars

    CERN Document Server

    Page, D; Weber, F; Page, Dany; Geppert, Ulrich; Weber, Fridolin

    2005-01-01

    The cooling of a compact star depends very sensitively on the state of dense matter at supranuclear densities, which essentially controls the neutrino emission, as well as on the structure of the stellar outer layers which control the photon emission. Open issues concern the hyperon population, the presence of meson condensates, superfluidity and superconductivity, and the transition of confined hadronic matter to quark matter. This paper describes these issues and presents cooling calculations based on a broad collection of equations of state for neutron star matter and strange matter. These results are tested against the body of observed cooling data.