Pesticide leaching through sandy and loamy fields – Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

International Nuclear Information System (INIS)

Rosenbom, Annette E.; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K.; Brüsch, Walter; Kjær, Jeanne

2015-01-01

The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. - Highlights: • Field-results reveal shortcomings in the EU authorization procedure for pesticides. • The plough layer can be bypassed via preferential transport in e.g. wormholes. • Pesticides properties are decisive for leaching pattern on the sandy fields. • The hydrogeological settings control the leaching patterns on the loamy fields. • Pesticide detection frequency seems to be independent of the month of the year. - Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme reveals shortcomings in the European Union authorization procedure for pesticides

Interaction of different irrigation strategies and soil textures on the nitrogen uptake of field grown potatoes

DEFF Research Database (Denmark)

Ahmadi, S.H.; Andersen, M.N.; Lærke, P.E.

2011-01-01

received 65% of FI after tuber bulking and lasted for six weeks until final harvest. Results showed that the irrigation treatments were not significantly different in terms of N uptake in the tubers, shoot, and whole crop. However, there was a statistical difference between the soil textures where plants...... in the loamy sand had the highest amount of N uptake. The interaction between irrigation treatments and soil textures was significant, and implied that under non-limiting water conditions, loamy sand is the suitable soil for potato production because plants can take up sufficient amounts of N and it could...... potentially lead to higher yield. However, under limited water conditions and applying water-saving irrigation strategies, sandy loam and coarse sand are better growth media because N is more available for the potatoes. The simple yield prediction model was developed that could explains ca. 96...

Interactions between Soil Texture and Placement of Dairy Slurry Application

DEFF Research Database (Denmark)

Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton

2011-01-01

soils. We compared leaching of slurry-applied bromide through intact soil columns (20 cm diam., 20 cm high) of differing textures following surface application or injection of slurry. The volumetric fraction of soil pores >30 μm ranged from 43% in a loamy sand to 28% in a sandy loam and 15% in a loam...... physical protection against leaching of bromide was reflected by 60.2% of the bromide tracer was recovered in the effluent after injection, compared with 80.6% recovery after surface application. No effect of slurry injection was observed in the loamy sand and sandy loam soils. Our findings point to soil...

Coarse woody debris assay in northern Arizona mixed-conifer and ponderosa pine forests

Science.gov (United States)

Joseph L. Ganey; Scott C. Vojta

2010-01-01

Coarse woody debris (CWD) provides important ecosystem services in forests and affects fire behavior, yet information on amounts and types of CWD typically is limited. To provide such information, we sampled logs and stumps in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in north-central Arizona. Spatial variability was prominent for all CWD parameters....

Linear mixing model applied to coarse spatial resolution data from multispectral satellite sensors

Science.gov (United States)

Holben, Brent N.; Shimabukuro, Yosio E.

1993-01-01

A linear mixing model was applied to coarse spatial resolution data from the NOAA Advanced Very High Resolution Radiometer. The reflective component of the 3.55-3.95 micron channel was used with the two reflective channels 0.58-0.68 micron and 0.725-1.1 micron to run a constrained least squares model to generate fraction images for an area in the west central region of Brazil. The fraction images were compared with an unsupervised classification derived from Landsat TM data acquired on the same day. The relationship between the fraction images and normalized difference vegetation index images show the potential of the unmixing techniques when using coarse spatial resolution data for global studies.

Effect of compost on erodibility of loamy sand under simulated rainfall

DEFF Research Database (Denmark)

Arthur, Emmanuel; Cornelis, W.M.; Vermang, J.

2011-01-01

Three types of composts [vegetable, fruit and yard waste compost (VFYW), garden waste compost (GW), and spent mushroom compost (SM)] were applied at a rate of 30 m3 ha−1 for 10 years to loamy sand, to determine its effect on the aggregate stability and susceptibility to water erosion. Aggregate...... significant improvement for any of the compost types. SM application resulted in a significant increase (51%) in the shear strength of the soil after rainfall. Long term compost application does not appreciably improve the resistance of loamy sand to water erosion....

The influence of reduced tillage on water regime and nutrient leaching in a loamy soil

OpenAIRE

Baigys, Giedrius; Gaigalis, Kazimieras; Kutra, Ginutis

2006-01-01

The effect of tillage technologies and terms on soil moisture regime and nitrate leaching was studied in field trials carried out on 0.76-1.36-ha fields. The study site was arranged in Pikeliai village (Kėdainiai district). The soil prevailing in the study site is Endocalcari - Endohypogleic Cambisol, sandy light loam and sandy loam on deeper layers of sandy loam and sandy light loam. The arable horizon contains sandy light loam, which is characteristic of the soils prevailing in the Middle L...

Final Environmental Assessment for Establishment of a New C-130 Landing Zone for 58 SOW

Science.gov (United States)

2013-10-01

sand about 10 inches thick. The subsoil is brown light sandy clay loam about 12 inches thick. The substratum is pink loam and sandy loam that has a...Madurez series soils is light brown loamy fine sand approximately 10 inches thick, with a brown light sandy clay loam subsoil about 12 inches thick...Closure Opening/Comments Count Sanitary Can w/folded seam 3” dia. x 4” ht. 1 Potted meat cans w/solder 2” dia. x 1 5/8” ht. ”Est-20-A” on base 2

Phytotoxic effects of Cu and Zn on soybeans grown in field-aged soils: their additive and interactive actions.

Science.gov (United States)

Kim, Bojeong; McBride, Murray B

2009-01-01

A field pot experiment was conducted to investigate the interactive phytotoxicity of soil Cu and Zn on soybean plants [Glycine max (L.) Merr.]. Two soils (Arkport sandy loam [coarse-loamy, mixed, active, mesic Lamellic Hapludalf] and Hudson silty clay loam [fine, illitic, mesic Glossaquic Hapludalf]) spiked with Cu, Zn, and combinations of both to reach the final soil metal range of 0 to 400 mg kg(-1) were tested in a 2-yr bioassay after 1 yr of soil-metal equilibration in the field. The soluble and easily-extractable fraction of soil Zn (or Cu), estimated by dilute CaCl2, increased linearly in response to the total Zn (or Cu) added. This linearity was, however, strongly affected where soils were treated with both metals in combination, most notably for Zn, as approximately 50% more of soil Zn was extracted into solution when the Cu level was high. Consequently, added Zn is less likely to be stabilized by aging than added Cu when both metals are present in field soils. The predictive model relating soil metal extractability to plant Zn concentration also revealed a significant Cu-Zn interaction. By contrast, the interaction between the two metals contributed little to explain plant Cu uptake. The additive action of soil Cu and Zn was of considerable importance in explaining plant biomass reduction. This work clearly demonstrates the critical roles of the properties of the soil, the nature of the metal, and the level of other toxic metals present on the development of differential phytotoxicity due to soil Cu and Zn.

Toxicity of Fipronil in Mississippi Soil Types Against Reticulitermes flavipes (Isoptera: Rhinotermitidae)

Science.gov (United States)

J. E. Mulrooney; P. D. Gerard

2007-01-01

Three soils (a silt loam, loamy sand, sandy loam) found in Mississippi and pure silica sand were treated with fipronil and bioassayed using eastern subterranean termites, Reticulitermes flavipes. Soils were treated with aqueous solutions of Termidor (fipronil) at concentrations of 0, 0.12, 0.25,2.5, 5.0 and 20.0 ppm (wt AI: wt soil) that brought the soils to 15%...

Light Gray Surface-Gleyed Loamy Sandy Soils of the Northern Part of Tambov Plain: Agroecology, Properties, and Diagnostics

Science.gov (United States)

Zaidel'man, F. R.; Stepantsova, L. V.; Nikiforova, A. S.; Krasin, V. N.; Dautokov, I. M.; Krasina, T. V.

2018-04-01

Light gray soils of Tambov oblast mainly develop from sandy and loamy sandy parent materials; these are the least studied soils in this region. Despite their coarse texture, these soils are subjected to surface waterlogging. They are stronger affected by the agrogenic degradation in comparison with chernozems and dark gray soils. Morphology, major elements of water regime, physical properties, and productivity of loamy sandy light gray soils with different degrees of gleyzation have been studied in the northern part of Tambov Plain in order to substantiate the appropriate methods of their management. The texture of these soils changes at the depth of 70-100 cm. The upper part is enriched in silt particles (16-30%); in the lower part, the sand content reaches 80-85%. In the nongleyed variants, middle-profile horizons contain thin iron-cemented lamellae (pseudofibers); in surface-gleyed variants, iron nodules are present in the humus horizon. The removal of clay from the humus horizon and its accumulation at the lithological contact and in pseudofibers promote surface subsidence and formation of microlows in the years with moderate and intense winter precipitation. The low range of active moisture favors desiccation of the upper horizons to the wilting point in dry years. The yield of cereal crops reaches 3.5-4.5 t/ha in the years with high and moderate summer precipitation on nongleyed and slightly gleyed light gray soils and decreases by 20-50% on strongly gleyed light gray soils. On light gray soils without irrigation, crop yields are unstable, and productivity of pastures is low. High yields of cereals and vegetables can be obtained on irrigated soils. In this case, local drainage measures should be applied to microlows; liming can be recommended to improve soil productivity.

Plant uptake and soil retention of phthalic acid applied to Norfolk sandy loam

International Nuclear Information System (INIS)

Dorney, J.R.; Weber, J.B.; Overcash, M.R.; Strek, H.J.

1985-01-01

Plant uptake and soil retention of 14 C carboxyl-labeled phthalic acid were studied at application rates of 0.6, 6.0, 60.0, and 600.0 ppm (soil dry weight) to Norfolk sandy loam (Typic Paleudult, fine loamy, kaolinitic, thermic). Height and dry weight of corn (Zea mays L. Pioneer 3368A) (21 day), tall fescue (Festuca arundinacea Schreb. Kentucky 31) (45 day) immature soybean (Glycine max (L.) Merr. Altoona) (21 day) plant, mature soybean plant, and mature wheat (Triticum aestivum L. Butte) straw were not affected by phthalic acid applied to soil. In addition, soybean seed and wheat seed dry weight were unaffected. Immature wheat (40 day) height decreased at the 600 ppm rate. Plant uptake of phthalic acid ranged from 0 to 23 ppm and was significantly above background for all plants and plant materials except soybean pods. Fescue and immature plants exhibited the highest concentration of phthalic acid while mature wheat plants and wheat seeds exhibited the least. Most of the phthalic acid volatilized or was decomposed from the soil by the end of the study; an average of only 5.7% of the originally applied chemical was recovered in both soil or plants. An average of 0.02% of the originally applied phthalic acid leached out of the treated zone. Considering the low toxicity of phthalic acid and its relatively rapid disappearance from soil, it is unlikely to become a health hazard from contaminated plants. However, plant uptake of other toxic organics could potentially become a hazard on soils treated with sludge containing significant quantities of these substances

Interaction of radionuclides with diluvium loams

International Nuclear Information System (INIS)

Martyanov, V.V.; Guskov, A.V.; Tkachenko, A.V.; Prozorov, L.B.; Karlina, O.K.

2005-01-01

Full text of publication follows: Primary goal of this research was to study the interaction of radioactive liquid waste with diluvium loams. A geology-hydro-geological characterisation of the RADON-site facility, located in the Southern Region of Russia, is given. According to the results of laboratory and field studies, the hydro-geological parameters of diluvium loams were designed, and their mineral and grain structures were investigated. It was established, that loams have low filtration properties. Definition of filtration coefficients (Kf) under laboratory conditions has shown low values (hydraulic gradient J=10, Kf = 8.10 -4 m/day). But the field experiment has shown, that Kf values vary from 0.1 up to 0.04 m/day with a gradient of J=1! (It is important to point at the selection of the initial data for modelling migration). Mineral structure: quartz - 43 %, montmorillonite - 28 %, hydro-micas - 17 %, iron hydroxides - 5 %, feldspar - 3,7 %, kaolinite - 2 %, carbonates - 1 %, organics - 0,3 %. The content of minerals known as good sorbents, makes up to 52 %. Laboratory experiments dedicated to the determination of sorption isotherms for various radionuclides were carried out. As a result, distribution coefficients (Kd) for 90 Sr, 137 Cs, 60 Co, 238 Pu were determined. Geology-hydro-geological and radiochemical data were used for the schematization of the system. Then, the mathematical modelling and forecasting of radionuclide migration was carried out. Two conservative scenarios were considered - full destruction of the waste matrices + water flow (lateral and vertical direction). As migrating components 90 Sr, 137 Cs, 60 Co, 238 Pu were considered. 90 Sr, 137 Cs, 60 Co, 238 Pu have different mobility due to their Kd ranging from tens and hundreds up to thousand ml/g depending on the properties of the diluvium loams. Initial radionuclide concentrations were as follow: 137 Cs -1.32.10 8 Bq/l, 60 Co - 2.52.10 7 Bq/l, 90 Sr - 1.81.10 7 Bq/l, 238 Pu - 7.78.10 6

Vertical Subsurface Flow Mixing and Horizontal Anisotropy in Coarse Fluvial Aquifers: Structural Aspects

Science.gov (United States)

Huggenberger, P.; Huber, E.

2014-12-01

Detailed descriptions of the subsurface heterogeneities in coarse fluvial aquifer gravel often lack in concepts to distinguish between the essence and the noise of a permeability structure and the ability to extrapolate site specific hydraulic information at the tens to several hundred meters scale. At this scale the heterogeneity strongly influences the anisotropies of the flow field and the mixing processes in groundwater. However, in many hydrogeological models the complexity of natural systems is oversimplified. Understanding the link between the dynamics of the surface processes of braided-river systems and the resulting subsurface sedimentary structures is the key to characterizing the complexity of horizontal and vertical mixing processes in groundwater. From the different depositional elements of coarse braided-river systems, the largest permeability contrasts can be observed in the scour-fills. Other elements (e.g. different types of gravel sheets) show much smaller variabilities and could be considered as a kind of matrix. Field experiments on the river Tagliamento (Northeast Italy) based on morphological observation and ground-penetrating radar (GPR) surveys, as well as outcrop analyses of gravel pit exposures (Switzerland) allowed us to define the shape, sizes, spatial distribution and preservation potential of scour-fills. In vertical sections (e.g. 2D GPR data, vertical outcrop), the spatial density of remnant erosional bounding surfaces of scours is an indicator for the dynamics of the braided-river system (lateral mobility of the active floodplain, rate of sediment net deposition and spatial distribution of the confluence scours). In case of combined low aggradation rate and low lateral mobility the deposits may be dominated by a complex overprinting of scour-fills. The delineation of the erosional bounding surfaces, that are coherent over the survey area, is based on the identification of angular discontinuities of the reflectors. Fence diagrams

Evaluation of fertilization-to-planting and fertilization-to-harvest intervals for safe use of noncomposted bovine manure in Wisconsin vegetable production.

Science.gov (United States)

Ingham, Steven C; Fanslau, Melody A; Engel, Rebecca A; Breuer, Jeffry R; Breuer, Jane E; Wright, Thomas H; Reith-Rozelle, Judith K; Zhu, Jun

2005-06-01

Fresh bovine manure was mechanically incorporated into loamy sand and silty clay loam Wisconsin soils in April 2004. At varying fertilization-to-planting intervals, radish, lettuce, and carrot seeds were planted; crops were harvested 90, 100, 110 or 111, and 120 days after manure application. As an indicator of potential contamination with fecal pathogens, levels of Escherichia coli in the manure-fertilized soil and presence of E. coli on harvested vegetables were monitored. From initial levels of 4.0 to 4.2 log CFU/g, E. coli levels in both manure-fertilized soils decreased by 2.4 to 2.5 log CFU/g during the first 7 weeks. However, E. coli was consistently detected from enriched soil samples through week 17, perhaps as a result of contamination by birds and other wildlife. In the higher clay silty clay loam soil, the fertilization-to-planting interval affected the prevalence of E. coli on lettuce but not on radishes and carrots. Root crop contamination was consistent across different fertilization-to-harvest intervals in silty clay loam, including the National Organic Program minimum fertilization-to-harvest interval of 120 days. However, lettuce contamination in silty clay loam was significantly (P < 0.10) affected by fertilization-to-harvest interval. Increasing the fertilization-to-planting interval in the lower clay loamy sand soil decreased the prevalence of E. coli on root crops. The fertilization-to-harvest interval had no clear effect on vegetable contamination in loamy sand. Overall, these results do not provide grounds for reducing the National Organic Program minimum fertilization-to-harvest interval from the current 120-day standard.

Proceedings of the International Symposium on Frozen Soil Impacts on Agricultural, Range, and Forest Lands Held at Spokane, Washington on March 21-22, 1990

Science.gov (United States)

1990-03-01

the United States. The soils were: a Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludult) from Watkinsville, GA ; a Barnes loam (fine loamy...1987). GLEAMS user manual. Lab Note South East Watershed Research Laboratory 110 187 WGK, Tifton , Ge, 1987. Lane, L.J., and V. A. Ferreira, (1980...as caps for processed uranium mill tailings in the western United States. The purpose of these barriers is to control radon gas release. The soil

A comparison of the morphological and physiochemical characteristics of ten carambola cultivars

Science.gov (United States)

Carambola (Averrhoa carambola L.) was grown on a Krome gravely loam soil (Loamy-skeletal, carbonic, hyperthermic Lithic Udorthents) in Miami, FL. Carambola morphological characteristics were determined by measuring fruit length, diameter and weight. Carambola physiochemical characteristics were det...

Time evolution of the coarse-graining-smoothed Wigner operator in an amplitude dissipative channel: from a pure state to a mixed state

International Nuclear Information System (INIS)

He, Rui; Fan, Hong-yi

2014-01-01

Based on the solution to the master equation of the density operator describing the amplitude dissipative channel, we derive the time evolution law of the coarse-graining-smoothed Wigner operator in this channel, which demonstrates how an initial pure state evolves into a mixed state, exhibiting decoherence

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

Science.gov (United States)

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

2018-01-01

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

Stratigraphy of fluvial sediment sequences and their palaeoenvironmental information in the foreland of the Serra dos Órgãos, southeastern Brazil

Science.gov (United States)

Kirchner, André; Nehren, Udo; Heinrich, Jürgen

2013-04-01

In the hinterland of Rio de Janeiro city the rivers Guapiaçu, Macacu and Iconha originate in the Serra dos Órgãos mountain range and drain into the Atlantic Ocean. Since their channelization in the 1950s, higher flow velocities caused an incision of the rivers into the valley fills. These circumstances provide the possibility to study the alluvial deposits along the streams during low water level and allow conclusions on palaeoenvironmental change and landscape history. Sedimentological investigations of 13 exposures as well as AMS 14C measurements were carried out to investigate sediment properties and reconstruct the sedimentation history within the floodplains. These results enable to distinguish three different facies units. A late Pleistocene Unit I can be detected at the base of the observed exposures and consists of clast-supported fine to coarse gravels. It can be assumed that the gravel bodies were formed by a climatically induced erosional-depositional cycle within a braided river system. The gravels are overlaid by Unit II, a grayish to bluish loam mainly of mid-Holocene age. During generally drier climates these loams have been deposited during high water stages or flooding events as a splay facies proximal to the rivers. A reduced flow competence and relatively stable morphodynamic conditions are assumed for that period. Unit III accumulated in the late Holocene typically consists of several meters of planar or cross bedded sands to fine gravels, interfingered by loamy inclusions, buried peat bogs and organic debris. Fining-upward sequences can be frequently studied within Unit III which were completed by loamy sediments in the uppermost parts of the exposures. The increased flow competence from Unit II to Unit III seems to be a fluvial response to the increased humidity of the late Holocene as well as the enhancement of El Niño-Southern Oscillation (ENSO). Heavy rainfall likely caused higher sediment supply from the steep slopes as well as a

Infiltration into cropped soils: effect of rain and sodium adsorption ratio-impacted irrigation water.

Science.gov (United States)

Suarez, Donald L; Wood, James D; Lesch, Scott M

2008-01-01

The sodium adsorption ratio (SAR) and salinity criteria for water suitability for irrigation have been developed for conditions where irrigation water is the only water source. It is not clear that these criteria are applicable to environments where there is a combination of rain and irrigation during the growing season. The interaction of rainfall with irrigation water is expected to result in increased sodicity hazard because of the low electrical conductivity of rain. In this study we examined the effects of irrigation waters of SAR 2, 4, 6, 8, and 10 mmol(1/2) L(-1/2) and electrical conductivities of 1 and 2 dS m(-1) on the infiltration rate of two soils with alternating cycles of rain (simulated with a rainfall sprinkler) and irrigation water, separated by drying cycles. The infiltration rate of surface samples from two soils, Kobase silty clay (fine, smectitic, frigid, Torrertic Haplustept) and Glendive very fine sandy loam (coarse-loamy, mixed superactive, calcareous, frigid Aridic Ustifluvent) were evaluated under alfalfa (Medicago sativa) cropped conditions for over 140 d and under full canopy cover. Reductions in infiltration were observed for both soils for SAR above 2, and the reductions became more severe with increasing SAR. Saturated hydraulic conductivity measurements taken from undisturbed cores at the end of the experiment were highly variable, suggesting that in situ infiltration measurements may be preferred when evaluating SAR effects.

Effects of irrigation strategies and soils on field-grown potatoes

DEFF Research Database (Denmark)

Ahmadi, Seyed Hamid; Andersen, Mathias Neumann; Plauborg, Finn

2010-01-01

Gas exchange was measured in potatoes (cv. Folva) grown in lysimeters (4.32 m2) in coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI...... measurements showed that An reached peak values during mid-morning and midday, while gs were highest during the morning. Intrinsic water use efficiency (An/gs) correlated linearly well with the leaf to air vapor pressure deficit (VPD) and the slope of the line revealed the rate of An/gs increase per each k......Pa increase in VPD, i.e. approximately 10 μmol mol-1. Transpiration efficiency (An/T) of PRD was higher than DI, which shows slightly better efficient water use than DI. The slope of the linear relationship between transpiration efficiency and VPD decreased from -2.03 to -1.04 during the time course...

Productivity of organic and conventional arable cropping systems in long-term experiments in Denmark

DEFF Research Database (Denmark)

Shah, Ambreen; Askegaard, Margrethe; Rasmussen, Ilse Ankjær

2017-01-01

manure there was a tendency for increased DM yield over time at all sites, whereas little response was seen in N yield. In the O4 rotation DM and N yields tended to increase at Foulum over time, but there was little change at Flakkebjerg. The DM yield gap between organic and conventional systems in the 3......A field experiment comparing different arable crop rotations was conducted in Denmark during 1997–2008 on three sites varying in climatic conditions and soil types, i.e. coarse sand (Jyndevand), loamy sand (Foulum), and sandy loam (Flakkebjerg). The crop rotations followed organic farm management......, and from 2005 also conventional management was included for comparison. Three experimental factors were included in the experiment in a factorial design: 1) crop rotation (organic crop rotations varying in use of whole-year green manure (O1 and O2 with a whole-year green manure, and O4 without...

EFFECTS OF ALKALINE SANDY LOAM ON SULFURIC SOIL ACIDITY AND SULFIDIC SOIL OXIDATION

Directory of Open Access Journals (Sweden)

Patrick S. Michael

2015-08-01

Full Text Available  In poor soils, addition of alkaline sandy loam containing an adequate proportion of sand, silt and clay would add value by improving the texture, structure and organic matter (OM for general use of the soils. In acid sulfate soils (ASS, addition of alkaline sandy would improve the texture and leach out salts as well as add a sufficient proportion of OM for vegetation establishment. In this study, addition of alkaline sandy loam into sulfuric soil effectively increased the pH, lowered the redox and reduced the sulfate content, the magnitude of the effects dependent on moisture content. Addition of alkaline sandy loam in combination with OM was highly effective than the effects of the lone alkaline sandy loam. When alkaline sandy was added alone or in combination with OM into sulfidic soil, the effects on pH and the redox were similar as in the sulfuric soil but the effect on sulfate content was variable. The effects under aerobic conditions were higher than under anaerobic conditions. The findings of this study have important implications for the general management of ASS where lime availability is a concern and its application is limited.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 42-54

Finding of No Significant Impact: Expand RV Storage Lot United States Air Force Academy, CO

Science.gov (United States)

2006-09-18

the surface layer is grayish brown gravelly sandy loam about 14 inches thick. The underlying material is light yellowish brown gravelly loamy sand...inhibit the urease activity of soil microbes by up to 47% and 35%, respectively, suggesting that sources of nitrogen other than urea should be used

Research Note:Determination of soil hydraulic properties using pedotransfer functions in a semi-arid basin, Turkey

Directory of Open Access Journals (Sweden)

M. Tombul

2004-01-01

Full Text Available Spatial and temporal variations in soil hydraulic properties such as soil moisture q(h and hydraulic conductivity K(q or K(h, may affect the performance of hydrological models. Moreover, the cost of determining soil hydraulic properties by field or laboratory methods makes alternative indirect methods desirable. In this paper, various pedotransfer functions (PTFs are used to estimate soil hydraulic properties for a small semi-arid basin (Kurukavak in the north-west of Turkey. The field measurements were a good fit with the retention curve derived using Rosetta SSC-BD for a loamy soil. To predict parameters to describe soil hydraulic characteristics, continuous PTFs such as Rosetta SSC-BD (Model H3 and SSC-BD-q33q1500 (Model H5 have been applied. Using soil hydraulic properties that vary in time and space, the characteristic curves for three soil types, loam, sandy clay loam and sandy loam have been developed. Spatial and temporal variations in soil moisture have been demonstrated on a plot and catchment scale for loamy soil. It is concluded that accurate site-specific measurements of the soil hydraulic characteristics are the only and probably the most promising method to progress in the future. Keywords: soil hydraulic properties, soil characteristic curves, PTFs

Prediction of cesium-134 and strontium-85 crop uptake based on soil properties

International Nuclear Information System (INIS)

Roca, M.C.; Vallejo, V.R.; Roig, M.; Tent, J.; Vidal, M.; Rauret, G.

1997-01-01

Nowadays, there is still the need to improve the quantification of parameters that affect radionuclide mobility. With this aim, radiocesium and radiostrontium soil-to-plant transfer was measured in lysimeters in a Calcic Luvisol, loamy soil and in a Fluvisol, loam-sandy soil, using lettuce [Lactuca sativa L. cv. Kinemontepas] and pea plants [Pisum sativum L. cv. Kelvedon Wonder]. Weighted Concentration Ratios (WCR), expressed as kg soil/kg plant, were calculated for different growth stages. Weighted Concentration Ratios were in general higher for 85Sr than for 134Cs, and also higher in the loam-sandy than in the loamy soil. To predict plant uptake, we evaluated a set of soil properties to define a prediction factor for the relative transfer in the two soils using cation exchange capacity (CEC) and radionuclide available fraction (fav) for radiostrontium, and soil solution composition, solid-liquid distribution coefficient, and radionuclide available fraction for radiocesium. The ratios of WCR in the loam-sandy and loamy soil were compared with the prediction factor. There was good agreement in lettuce for 85Sr (ratio of WCR was 5.4 for seedling and 3.9 for commercial samples, whereas prediction factor was 3.1) and for 134Cs (ratio of WCR was 5.1 for seedling and 5.5 for commercial samples, the prediction factor being 5.1), although for pea only the relative root uptake of radiocesium in seedling pea was well predicted (the ratio of WCR was 8.8, the prediction factor being 9.1). These soil parameters improved former predictions based solely on the fav, although factors depending on plant physiology should be better evaluated

A Factorial Design Approach to Analyse the Effect of Coarse Recycled Concrete Aggregates on the Properties of Hot Mix Asphalt

Science.gov (United States)

Tanty, Kiranbala; Mukharjee, Bibhuti Bhusan; Das, Sudhanshu Shekhar

2018-02-01

The present study investigates the effect of replacement of coarse fraction of natural aggregates by recycled concrete aggregates on the properties of hot mix asphalt (HMA) using general factorial design approach. For this two factors i.e. recycled coarse aggregates percentage [RCA (%)] and bitumen content percentage [BC (%)] are considered. Tests have been carried out on the HMA type bituminous concrete, prepared with varying RCA (%) and BC (%). Analysis of variance has been performed on the experimental data to determine the effect of the chosen factors on various parameters such as stability, flow, air void, void mineral aggregate, void filled with bitumen and bulk density. The study depicts that RCA (%) and BC (%) have significant effect on the selected responses as p value is less than the chosen significance level. In addition to above, the outcomes of the statistical analysis indicate that interaction between factors have significant effects on void mineral aggregate and bulk density of bituminous concrete.

A Factorial Design Approach to Analyse the Effect of Coarse Recycled Concrete Aggregates on the Properties of Hot Mix Asphalt

Science.gov (United States)

Tanty, Kiranbala; Mukharjee, Bibhuti Bhusan; Das, Sudhanshu Shekhar

2018-06-01

The present study investigates the effect of replacement of coarse fraction of natural aggregates by recycled concrete aggregates on the properties of hot mix asphalt (HMA) using general factorial design approach. For this two factors i.e. recycled coarse aggregates percentage [RCA (%)] and bitumen content percentage [BC (%)] are considered. Tests have been carried out on the HMA type bituminous concrete, prepared with varying RCA (%) and BC (%). Analysis of variance has been performed on the experimental data to determine the effect of the chosen factors on various parameters such as stability, flow, air void, void mineral aggregate, void filled with bitumen and bulk density. The study depicts that RCA (%) and BC (%) have significant effect on the selected responses as p value is less than the chosen significance level. In addition to above, the outcomes of the statistical analysis indicate that interaction between factors have significant effects on void mineral aggregate and bulk density of bituminous concrete.

Termite Infestation Associated with Type of Soil in Pulau Pinang, Malaysia (Isoptera: Rhinotermitidae)

OpenAIRE

Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

2013-01-01

Nine soil samples from nine buildings infested with Coptotermes gestroi in Pulau Pinang, Malaysia, were tested for the type of soil texture. The soil texture analysis procedures used the hydrometer method. Four of nine buildings (44%) yielded loamy sand-type soil, whereas five of nine buildings (56%) contained sandy loam-type soil.

Termite infestation associated with type of soil in pulau pinang, malaysia (isoptera: rhinotermitidae).

Science.gov (United States)

Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

2013-12-01

Nine soil samples from nine buildings infested with Coptotermes gestroi in Pulau Pinang, Malaysia, were tested for the type of soil texture. The soil texture analysis procedures used the hydrometer method. Four of nine buildings (44%) yielded loamy sand-type soil, whereas five of nine buildings (56%) contained sandy loam-type soil.

Effects of exchangeable Ca:Mg ratio on the dispersion of soils some ...

African Journals Online (AJOL)

The soils studied were acidic, low in nutrient level, showed high dispersion rate, high water- dispersible clay content and the textural class were loamy sand and sandy loam. The exchangeable Ca2+ and Mg2+ contents of the soils dominated the exchange complex. The cation exchange capacity (CEC) ranges between 4 ...

Bioavailability of cerium oxide nanoparticles to Raphanus sativus L. in two soils.

Science.gov (United States)

Zhang, Weilan; Musante, Craig; White, Jason C; Schwab, Paul; Wang, Qiang; Ebbs, Stephen D; Ma, Xingmao

2017-01-01

Cerium oxide nanoparticles (CeO 2 NP) are a common component of many commercial products. Due to the general concerns over the potential toxicity of engineered nanoparticles (ENPs), the phytotoxicity and in planta accumulation of CeO 2 NPs have been broadly investigated. However, most previous studies were conducted in hydroponic systems and with grain crops. For a few studies performed with soil grown plants, the impact of soil properties on the fate and transport of CeO 2 NPs was generally ignored even though numerous previous studies indicate that soil properties play a critical role in the fate and transport of environmental pollutants. The objectives of this study were to evaluate the soil fractionation and bioavailability of CeO 2 NPs to Raphanus sativus L (radish) in two soil types. Our results showed that the silty loam contained slightly higher exchangeable fraction (F1) of cerium element than did loamy sand soil, but significantly lower reducible (F2) and oxidizable (F3) fractions as CeO 2 NPs concentration increased. CeO 2 NPs associated with silicate minerals or the residue fraction (F4) dominated in both soils. The cerium concentration in radish storage root showed linear correlation with the sum of the first three fractions (r 2  = 0.98 and 0.78 for loamy sand and silty loam respectively). However, the cerium content in radish shoots only exhibited strong correlations with F1 (r 2  = 0.97 and 0.89 for loamy sand and silty loam respectively). Overall, the results demonstrated that soil properties are important factors governing the distribution of CeO 2 NPs in soil and subsequent bioavailability to plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Nonlinear Multigrid solver exploiting AMGe Coarse Spaces with Approximation Properties

DEFF Research Database (Denmark)

Christensen, Max la Cour; Villa, Umberto; Engsig-Karup, Allan Peter

The paper introduces a nonlinear multigrid solver for mixed finite element discretizations based on the Full Approximation Scheme (FAS) and element-based Algebraic Multigrid (AMGe). The main motivation to use FAS for unstructured problems is the guaranteed approximation property of the AMGe coarse...... properties of the coarse spaces. With coarse spaces with approximation properties, our FAS approach on unstructured meshes has the ability to be as powerful/successful as FAS on geometrically refined meshes. For comparison, Newton’s method and Picard iterations with an inner state-of-the-art linear solver...... are compared to FAS on a nonlinear saddle point problem with applications to porous media flow. It is demonstrated that FAS is faster than Newton’s method and Picard iterations for the experiments considered here. Due to the guaranteed approximation properties of our AMGe, the coarse spaces are very accurate...

Impact of pulp and paper mill effluents and solid wastes on soil mineralogical and physicochemical properties.

Science.gov (United States)

Adhikari, Gopi; Bhattacharyya, Krishna G

2015-03-01

The present study was carried out to evaluate the impact of the effluents and the solid wastes generated by a giant pulp and paper mill in the northeastern part of India on soil mineralogy of the area. The impacts were monitored by analysis of soil samples from seven sites located in the potential impact zone and a control site where any kind of effluent discharge or solid waste dumping was absent. The soil belonged to medium texture type (sandy clay loam, sandy loam, loamy sand, and silt loam), and the soil aggregate analysis indicated higher levels of organic carbon, pH, electrical conductivity, effective cation exchange capacity, and mean weight diameter at sites receiving effluents and solid wastes from the pulp and paper mill. Depletion in soil silica level and in feldspar and quartz contents and rise in iron and calcium contents at the sites receiving effluents from the pulp and paper mill indicated significant influence on soil mineralogy. The soil contained a mixture of minerals consisting of tectosilicates (with silicate frameworks as in quartz or feldspar), phylosilicates (layered clays like kaolinite, smectite, chlorite, illite, etc.), and carbonates. Absence of pure clay minerals indicated a state of heterogeneous intermediate soil clay transformation. The significance of the mixed mineralogy in relation to the disposal of effluents and dumping of solid wastes is discussed in details.

Using of Porcelinite as Coarse Aggregate in Concrete

Directory of Open Access Journals (Sweden)

Haifa Saleh

2015-02-01

Full Text Available In this research the ability of using porcelinite as coarse aggregate to produce light weight concrete was investigated.  The experimental program consists of preparing and testing a mixes to investigate mechanical properties of concrete, with a total of 15 cubes (100×100×100 mm, 30 cylinders (100×200 mm. The tests include compressive strength, splitting tensile strength, fresh and hardened density of  light weight concrete for different porcelinite percentages ranged between(0% to 100% of the coarse aggregate weight. The obtained results for tested specimens were compared to control one. Test results indicated that using of porcelinite in concrete mix reduces the strength of concrete Porcelinite aggregate represents a reduction in density ranging between (10%-36% of normal weight concrete, therefore there is an advantage  using this type of light weight aggregate in this country where soil bearing capacity is low in most construction sites.

effect of tractor forward speed on sandy loam soil physical ...

African Journals Online (AJOL)

Dr Obe

Ilorin on a sandy loam soil to evaluate the effect of the imposition of different .... of the blade is 10.5cm. ... arranged in an inverted cone shape with ... replicates were taken for each speed run. The ..... Thakur, T. C; A. Yadav; B. P. Varshney and.

Eleven years' effect of conservation practices for temperate sandy loams: II. Soil pore characteristics

DEFF Research Database (Denmark)

Abdollahi, Lotfallah; Munkholm, Lars Juhl

2017-01-01

Conservation agriculture (CA) is regarded by many as a sustainable intensification strategy. Minimal soil disturbance in combination with residue retention are important CA components. This study examined the long-term effects of crop rotation, residue retention, and tillage on soil pore characte......Conservation agriculture (CA) is regarded by many as a sustainable intensification strategy. Minimal soil disturbance in combination with residue retention are important CA components. This study examined the long-term effects of crop rotation, residue retention, and tillage on soil pore...... characteristics of two Danish sandy loams. Rotation R2 is a rotation of winter crops (mainly cereals) with residues retained, rotation R3 a mix of winter and spring crops (mainly cereals) with residues removed, and rotation R4 the same mix of winter and spring crops, but with residues retained. Each rotation...... included the tillage treatments: moldboard plowing to 20-cm depth (MP), harrowing to 8- to 10-cm depth (H) and direct drilling (D). Soil cores were taken from the topsoil (4–8, 12–16, 18–27 cm) in mid-autumn 2013 and early spring 2014. Water retention, air permeability, and gas diffusivity was determined...

An experimental study on the hazard assessment and mechanical properties of porous concrete utilizing coal bottom ash coarse aggregate in Korea.

Science.gov (United States)

Park, Seung Bum; Jang, Young Il; Lee, Jun; Lee, Byung Jae

2009-07-15

This study evaluates quality properties and toxicity of coal bottom ash coarse aggregate and analyzes mechanical properties of porous concrete depending on mixing rates of coal bottom ash. As a result, soundness and resistance to abrasion of coal bottom ash coarse aggregate were satisfied according to the standard of coarse aggregate for concrete. To satisfy the standard pertaining to chloride content, the coarse aggregates have to be washed more than twice. In regards to the result of leaching test for coal bottom ash coarse aggregate and porous concrete produced with these coarse aggregates, it was satisfied with the environment criteria. As the mixing rate of coal bottom ash increased, influence of void ratio and permeability coefficient was very little, but compressive and flexural strength decreased. When coal bottom ash was mixed over 40%, strength decreased sharply (compressive strength: by 11.7-27.1%, flexural strength: by maximum 26.4%). Also, as the mixing rate of coal bottom ash increased, it was confirmed that test specimens were destroyed by aggregate fracture more than binder fracture and interface fracture. To utilize coal bottom ash in large quantities, it is thought that an improvement method in regards to strength has to be discussed such as incorporation of reinforcing materials and improvement of aggregate hardness.

Distribution of transformed organic matter in structural units of loamy sandy soddy-podzolic soil

Science.gov (United States)

Kogut, B. M.; Yashin, M. A.; Semenov, V. M.; Avdeeva, T. N.; Markina, L. G.; Lukin, S. M.; Tarasov, S. I.

2016-01-01

The effect of land use types and fertilizing systems on the structural and aggregate composition of loamy sandy soddy-podzolic soil and the quantitative parameters of soil organic matter has been studied. The contribution of soil aggregates 2-1 mm in size to the total Corg reserve in the humus horizon is higher than the contributions of other aggregates by 1.3-4.2 times. Reliable correlations have been revealed between the contents of total (Corg), labile (Clab), and active (C0) organic matter in the soil. The proportion of C0 is 44-70% of Clab extractable by neutral sodium pyrophosphate solution. The contributions of each of the 2-1, 0.5-0.25, and fractions to the total C0 reserve are 14-21%; the contributions of each of the other fractions are 4-12%. The chemically labile and biologically active components of humic substances reflect the quality changes of soil organic matter under agrogenic impacts. A conceptual scheme has been proposed for the subdivision of soil organic matter into the active, slow (intermediate), and passive pools. In the humus horizon of loamy sandy soddy-podzolic soil, the active, slow, and passive pools contain 6-11, 34-65, and 26-94% of the total Corg, respectively.

influence of tillage practices on physical properties of a sandy loam

African Journals Online (AJOL)

DR. AMINU

many regions of the world if the mechanics of tillage effects on soil physical properties is to be well understood. Thus, the ... tillage systems on water storage of a sandy loam soil after 22 years of ..... Soil infiltration ... and processes. Academy ...

Soil structure and earthworm activity in an marine silt loam under pasture versus arable land

NARCIS (Netherlands)

Jongmans, A.G.; Pulleman, M.M.; Marinissen, J.C.Y.

2001-01-01

Agricultural management influences soil organic matter (SOM) and earthworm activity which interact with soil structure. We aimed to describe the change in earthworm activity and related soil (micro)structure and SOM in a loamy Eutrodept as affected by permanent pasture (PP) and conventional arable

Aggregate-associated carbon and nitrogen in reclaimed sandy loam soils

Energy Technology Data Exchange (ETDEWEB)

Wick, A.F.; Stahl, P.D.; Ingram, L.J. [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States)

2009-11-15

Minimal research has been conducted on aggregate, C, and N in coarse-textured soils used to reclaim surface coal mine lands. Furthermore, little is known about the contribution different plant communities make to the recovery of aggregation in these soils. Two chronosequences of semiarid reclaimed sites with sandy loam soils were sampled under shrub- and grass-dominated communities. Aggregation, aggregate fractions, and associated C and N were measured. No definitive trends of increasing macroaggregates between sites were observed undershrubs; however, macro- and microaggregation was greater in the 16-yr-old (0.20 and 0.23 kg aggregate kg{sup -1} soil, respectively) than in the 5-yr-old soils (0.02 and 0.08 kg aggregate kg{sup -1} soil, respectively) under grasses. Although C and N concentrations were drastically reduced (50-75%) with mining activity between the <1-yr-old and native soils, aggregate C and N concentrations tinder shrubs and grasses were similar to each other and to the native soils in the 5-yr-old site. Sods under grass in the 16-yr-old site had lower available and aggregate-occluded C and N concentrations than the 5-yr-old site, while C and N concentrations did not change between 5- and 16-yr-old soils under shrubs. Conversely, aggregate C and N pool sizes under shrubs and grasses both increased with site age to conditions similar to those observed in the native soil. Reclaimed shrub site soils had consistently higher C concentrations in the older reclaimed sites (10 and 16 yr old) than the soils under grasses, indicating greater accumulation and retention of C and N in organic material under shrub than grass communities in semiarid reclaimed sites.

Evaluation of using crushed brick as coarse aggregate in concrete layer within rigid highway pavement

Directory of Open Access Journals (Sweden)

Alwash Ali

2018-01-01

Full Text Available Most of the present studies related to the field of highway pavement construction technique tend to make use of the local available materials as substitutes for the imported and necessary materials for some of the practical application. For this reason this research aims at looking for the prospect of used locally available aggregate such as crushed clay bricks for the aim of producing proper concrete with suitable thermal and mechanical properties. Experimental investigations have been carried out to asses the effect of partial replacement of coarse aggregate by free manually crushed Brick with percentages (10, 20, 30 and 40% of virgin coarse aggregate in concrete mix for highway rigid pavement. While the percentage (0% replacement represent reference mix. Mix proportion based on the target of compressive strength for all replacement percentage of (33 MPa at (28 days to achieve AASHTO requirement for highway concrete rigid pavement .The results of flexural strength, modulus of elasticity, density and thermal conductivity refers to better performance (less thickness of concrete layer with large spacing between contraction or expansion joints and less stresses due to warping induced concrete layer for concrete mix with 20% crushed brick as replacement of coarse aggregate.

The Effect of Compost and the Ripe Fruit Waste of Fig on some Physical Properties of Surface Soil

Directory of Open Access Journals (Sweden)

zahra dianat maharluei

2017-02-01

Full Text Available Introduction: In arid and semi-arid soils, low organic matter is one of the barriers to achieving optimal performance. The soils with more organic matter have a better structure and are more resistant to erosive factors such as water and wind. Soil organic matter has a particular importance and has significant impact on the stability of soil aggregates, the extension of plant root system, carbon and water cycles and soil resistance to erosion. This substance acts as a cementing agent and plays an important role in soil flocculation and formation of resistant aggregates.Also, the addition of organic matter to the soil increases soil porosity and decreases soil bulk density. Materials and Methods: In this research, the effect of the two types of organic matter (compost and the ripe fruit waste of fig on some soil physical properties was studied. A factorial experiment based on completely randomized design, including the four levels of compost and the ripe fruit waste of fig (0, 1, 2 and 4 by weight % and three soil types (loamy sand, loam and silty clay loam with three replications was carried out. The soil samples were collected from the three territories of Fars Province: loamy sand soil from Shiraz, loamy soil from Maharlu and Silty clay loam soil from Zarghan area. The soil samples were air dried and passed through a 2 mm sieve. The physical properties including the bulk density, particle density, porosity, moisture content and soil crust strength was measured. In this research, the soil texture by hydrometer method, Electrical conductivity of the soil saturated paste extract by electrical conductivity meter, saturated paste pH by pH meter, seedling emergence test, soil crust strength by a pocket penetrometer (HUMBOLDT MFG.CO. bulk density by cylindrical sample and particle density by pycnometer method were measured. The fig fruit treatments were prepared by thoroughly mixing the dried powder of ripe fig fruit passed through a 2 mm sieve (with

Neutron Gauge Calibration Curve as Affected by Chloride Concentration and Bulk Density of Loam Soil

International Nuclear Information System (INIS)

AL-Hasani, A.A.; Fahad, A.A.; Shihab, R.M.

2010-01-01

chloride concentration and bulk density are considered among important factors affecting calibration curve of neutron gauge in the soil.The aim of this study was to investigate the effect of chloride concentration and bulk density of a loam soil on neutron gauge calibration curve.Sufficient amount of loam soil was air dried screened through a 2 mm sieve,and divided into three equal portions.Sodium chloride of 2.5 and 6.6g kg'-1 soil was added to the first and second portions,respectively.The third portion was left as a control.The soil then moistened and mixed well to make volumetric water content within the range of 0.01 to 0.24 cm 3 cm - 3. The moist soil was packed into an iron drum 0.80 m diameter and 1.00 m height to obtain bulk densities of 1.10 and 1.30 to 1.60 Mg m - 3 for uncompacted soil,respectively.Access tube 0.05 m inner diameter was installed in the center of the drum.Three readings from CPN 503 neutron gauge were taken at each 0.15,0.30, 0.45,and 0.75 m depth.Results indicated that the count (counts/standard count) for an aqueous solution decreased with the increase in chloride concentration.Similarly, the slope of the linear calibration curves of the investigated soil decreased with the increase in chloride concentration.Shifting of the curves was 9 to 10%for the uncompacted soil, whereas it was 12 to 14 % for the compacted of low and high concentration of chloride, respectively . Results of changing bulk density always reduced the slope value as compared with the uncorrected count ratio.

Dark gray soils on two-layered deposits in the north of Tambov Plain: Agroecology, properties, and diagnostics

Science.gov (United States)

Zaidelman, F. R.; Nikiforova, A. S.; Stepantsova, L. V.; Volokhina, V. P.

2012-05-01

Dark gray soils in the Tambov Plain are developed from the light-textured glaciofluvial deposits underlain by the calcareous loam. Their morphology, water regime, and productivity are determined by the depth of the slightly permeable calcareous loamy layer, relief, and the degree of gleyzation. The light texture of the upper layer is responsible for its weak structure, high density, the low content of productive moisture, and the low water-holding capacity. If the calcareous loam is at a depth of 100-130 cm, dark gray soils are formed; if it lies at a depth of 40-70 cm, temporary perched water appears in the profile, and dark gray contact-gleyed soils are formed. Their characteristic pedofeatures are skeletans in the upper layers, calcareous nodules in the loamy clay layer, and iron nodules in the podzolized humus and podzolic horizons. The appearance of Fe-Mn concretions is related to gleyzation. The high yield of winter cereals is shown to be produced on the dark gray soils; the yields of spring crops are less stable. Spring cereals should not be grown on the contact-gleyed dark gray soils.

Assessment of structural stability of a degraded sandy clay loam soil ...

African Journals Online (AJOL)

The effects of bare, two legumes and four grasses cover treatments on the structural stability of a sandy clay loam Ultisol were studied within a two year period. The experiment was of a randomised complete block design with seven treatments. The legume treatments were Centrosema pubescens (Ce) and Pueraria ...

NONLINEAR MULTIGRID SOLVER EXPLOITING AMGe COARSE SPACES WITH APPROXIMATION PROPERTIES

Energy Technology Data Exchange (ETDEWEB)

Christensen, Max La Cour [Technical Univ. of Denmark, Lyngby (Denmark); Villa, Umberto E. [Univ. of Texas, Austin, TX (United States); Engsig-Karup, Allan P. [Technical Univ. of Denmark, Lyngby (Denmark); Vassilevski, Panayot S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-01-22

The paper introduces a nonlinear multigrid solver for mixed nite element discretizations based on the Full Approximation Scheme (FAS) and element-based Algebraic Multigrid (AMGe). The main motivation to use FAS for unstruc- tured problems is the guaranteed approximation property of the AMGe coarse spaces that were developed recently at Lawrence Livermore National Laboratory. These give the ability to derive stable and accurate coarse nonlinear discretization problems. The previous attempts (including ones with the original AMGe method, [5, 11]), were less successful due to lack of such good approximation properties of the coarse spaces. With coarse spaces with approximation properties, our FAS approach on un- structured meshes should be as powerful/successful as FAS on geometrically re ned meshes. For comparison, Newton's method and Picard iterations with an inner state-of-the-art linear solver is compared to FAS on a nonlinear saddle point problem with applications to porous media ow. It is demonstrated that FAS is faster than Newton's method and Picard iterations for the experiments considered here. Due to the guaranteed approximation properties of our AMGe, the coarse spaces are very accurate, providing a solver with the potential for mesh-independent convergence on general unstructured meshes.

Chemical-mineralogical characterisation of coarse recycled concrete aggregate

International Nuclear Information System (INIS)

Limbachiya, M.C.; Marrocchino, E.; Koulouris, A.

2007-01-01

The construction industry is now putting greater emphasis than ever before on increasing recycling and promoting more sustainable waste management practices. In keeping with this approach, many sectors of the industry have actively sought to encourage the use of recycled concrete aggregate (RCA) as an alternative to primary aggregates in concrete production. The results of a laboratory experimental programme aimed at establishing chemical and mineralogical characteristics of coarse RCA and its likely influence on concrete performance are reported in this paper. Commercially produced coarse RCA and natural aggregates (16-4 mm size fraction) were tested. Results of X-ray fluorescence (XRF) analyses showed that original source of RCA had a negligible effect on the major elements and a comparable chemical composition between recycled and natural aggregates. X-ray diffraction (XRD) analyses results indicated the presence of calcite, portlandite and minor peaks of muscovite/illite in recycled aggregates, although they were directly proportioned to their original composition. The influence of 30%, 50%, and 100% coarse RCA on the chemical composition of equal design strength concrete has been established, and its suitability for use in a concrete application has been assessed. In this work, coarse RCA was used as a direct replacement for natural gravel in concrete production. Test results indicated that up to 30% coarse RCA had no effect on the main three oxides (SiO 2 , Al 2 O 3 and CaO) of concrete, but thereafter there was a marginal decrease in SiO 2 and increase in Al 2 O 3 and CaO contents with increase in RCA content in the mix, reflecting the original constituent's composition

Chemical-mineralogical characterisation of coarse recycled concrete aggregate.

Science.gov (United States)

Limbachiya, M C; Marrocchino, E; Koulouris, A

2007-01-01

The construction industry is now putting greater emphasis than ever before on increasing recycling and promoting more sustainable waste management practices. In keeping with this approach, many sectors of the industry have actively sought to encourage the use of recycled concrete aggregate (RCA) as an alternative to primary aggregates in concrete production. The results of a laboratory experimental programme aimed at establishing chemical and mineralogical characteristics of coarse RCA and its likely influence on concrete performance are reported in this paper. Commercially produced coarse RCA and natural aggregates (16-4 mm size fraction) were tested. Results of X-ray fluorescence (XRF) analyses showed that original source of RCA had a negligible effect on the major elements and a comparable chemical composition between recycled and natural aggregates. X-ray diffraction (XRD) analyses results indicated the presence of calcite, portlandite and minor peaks of muscovite/illite in recycled aggregates, although they were directly proportioned to their original composition. The influence of 30%, 50%, and 100% coarse RCA on the chemical composition of equal design strength concrete has been established, and its suitability for use in a concrete application has been assessed. In this work, coarse RCA was used as a direct replacement for natural gravel in concrete production. Test results indicated that up to 30% coarse RCA had no effect on the main three oxides (SiO2, Al2O3 and CaO) of concrete, but thereafter there was a marginal decrease in SiO2 and increase in Al2O3 and CaO contents with increase in RCA content in the mix, reflecting the original constituent's composition.

Improving the Quality of Mixed Recycled Coarse Aggregates from Construction and Demolition Waste Using Heavy Media Separation with Fe3O4 Suspension

Directory of Open Access Journals (Sweden)

Heonchan Kang

2017-01-01

Full Text Available The primary objectives of this study are to investigate the feasibility of a heavy media separation process with magnetite (Fe3O4 suspension for upgrading the quality of mixed recycled coarse aggregates from construction and demolition waste (CDW in Korea and to determine a range of effective operating density of Fe3O4 suspension for producing high-quality RCA acceptable to structural concrete applications. For the purposes, six 200 kg recycled coarse aggregates (RCAs samples were collected from a conventional recycling plant in Korea. Subsequently, the samples were processed by a heavy media separation process using Fe3O4 suspensions with various densities from 2.65 g/cm3 to 2.40 g/cm3 with an interval of 0.05 g/cm3. Next, a series of tests was performed in the laboratory to evaluate properties of finished sink and float products from the HMS processes, including oven-dry density, absorption capacity, and physical durability. Furthermore, compressive strength of concrete cylinders (150 mm by 300 mm made of the finished sink products from Fe3O4 suspensions with three different densities (2.4, 2.5, and 2.6 g/cm3 was tested in this study. As a result, it was demonstrated that the HMS process using Fe3O4 suspension with a density ranging between 2.40 and 2.65 g/cm3 was effective for upgrading mixed CDW RCAs in Korea to high-quality RCAs acceptable for structural concrete applications.

Predictive coarse-graining

Energy Technology Data Exchange (ETDEWEB)

Schöberl, Markus, E-mail: m.schoeberl@tum.de [Continuum Mechanics Group, Technical University of Munich, Boltzmannstraße 15, 85748 Garching (Germany); Zabaras, Nicholas [Institute for Advanced Study, Technical University of Munich, Lichtenbergstraße 2a, 85748 Garching (Germany); Department of Aerospace and Mechanical Engineering, University of Notre Dame, 365 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Koutsourelakis, Phaedon-Stelios [Continuum Mechanics Group, Technical University of Munich, Boltzmannstraße 15, 85748 Garching (Germany)

2017-03-15

We propose a data-driven, coarse-graining formulation in the context of equilibrium statistical mechanics. In contrast to existing techniques which are based on a fine-to-coarse map, we adopt the opposite strategy by prescribing a probabilistic coarse-to-fine map. This corresponds to a directed probabilistic model where the coarse variables play the role of latent generators of the fine scale (all-atom) data. From an information-theoretic perspective, the framework proposed provides an improvement upon the relative entropy method and is capable of quantifying the uncertainty due to the information loss that unavoidably takes place during the coarse-graining process. Furthermore, it can be readily extended to a fully Bayesian model where various sources of uncertainties are reflected in the posterior of the model parameters. The latter can be used to produce not only point estimates of fine-scale reconstructions or macroscopic observables, but more importantly, predictive posterior distributions on these quantities. Predictive posterior distributions reflect the confidence of the model as a function of the amount of data and the level of coarse-graining. The issues of model complexity and model selection are seamlessly addressed by employing a hierarchical prior that favors the discovery of sparse solutions, revealing the most prominent features in the coarse-grained model. A flexible and parallelizable Monte Carlo – Expectation–Maximization (MC-EM) scheme is proposed for carrying out inference and learning tasks. A comparative assessment of the proposed methodology is presented for a lattice spin system and the SPC/E water model.

Behaviour of fibre reinforced concrete using steel slag coarse aggregate produced in Qatar

Directory of Open Access Journals (Sweden)

Alnahhal Wael

2017-01-01

Full Text Available The state of Qatar suffers from the shortage of natural resources needed for concrete production. Therefore, it is essential to investigate the feasibility of using by-product recycled materials as aggregates to maintain the concrete construction industry. Several types of recyclable materials are currently used in concrete. One of the potential resources of recycled concrete is steel slag. Knowing that Steel slag is the most significant solid waste generated by Qatar Steel Company in Qatar, replacing of natural coarse aggregate with steel slag aggregate will have a significant environmental and economic impact to the state of Qatar. This paper presents the compression and flexural test results of different concrete mixes made of steel slag coarse aggregate combined with a newly developed basalt chopped fibres. The parameters investigated included the volume fraction of the fibre used and the type of coarse aggregates (natural aggregates “Gabbro” and steel slag aggregates. Plain concrete specimens containing natural coarse aggregates and steel slag aggregates with no fibres added were also tested to serve as control. Test results showed that adding the basalt chopped fibres to the concrete mixes enhanced their flexural tensile strengths at different percentages. In addition, the compressive strength of concrete made with steel slag aggregate was higher than that made with natural gabbro aggregate. Test results clearly showed that steel slag aggregates can be used as sustainable and eco-friendly alternative materials in concrete structures.

A coarse-to-fine scheme for groupwise registration of multisensor images

Directory of Open Access Journals (Sweden)

Yinghao Li

2016-11-01

Full Text Available Ensemble registration is concerned with a group of images that need to be registered simultaneously. It is challenging but important for many image analysis tasks such as vehicle detection and medical image fusion. To solve this problem effectively, a novel coarse-to-fine scheme for groupwise image registration is proposed. First, in the coarse registration step, unregistered images are divided into reference image set and float image set. The images of the two sets are registered based on segmented region matching. The coarse registration results are used as an initial solution for the next step. Then, in the fine registration step, a Gaussian mixture model with a local template is used to model the joint intensity of coarse-registered images. Meanwhile, a minimum message length criterion-based method is employed to determine the unknown number of mixing components. Based on this mixture model, a maximum likelihood framework is used to register a group of images. To evaluate the performance of the proposed approach, some representative groupwise registration approaches are compared on different image data sets. The experimental results show that the proposed approach has improved performance compared to conventional approaches.

LAMBERSART "LES CONQUERANTS" (DEULE VALLEY, NORTH OF FRANCE) : A WEICHSELIAN EARLY-PLENIGLACIAL SLOPE-BOTTOM VALLEY TRANSITION

NARCIS (Netherlands)

Deschodt, Laurent; Munaut, Andre-Valentin; Limondin-Lozouet, Nicole; Boulen, Muriel

2008-01-01

The Lambersart "les Conquerants" trench sequence is made of a Shelly loam topped by coarse alluviums. The whole is covered by several meters thick pleniglacial loess. The palynological and malacological data shows that this Shelly loam deposit occured during Early Glacial, in cold and moist

Quantum mechanics/coarse-grained molecular mechanics (QM/CG-MM).

Science.gov (United States)

Sinitskiy, Anton V; Voth, Gregory A

2018-01-07

Numerous molecular systems, including solutions, proteins, and composite materials, can be modeled using mixed-resolution representations, of which the quantum mechanics/molecular mechanics (QM/MM) approach has become the most widely used. However, the QM/MM approach often faces a number of challenges, including the high cost of repetitive QM computations, the slow sampling even for the MM part in those cases where a system under investigation has a complex dynamics, and a difficulty in providing a simple, qualitative interpretation of numerical results in terms of the influence of the molecular environment upon the active QM region. In this paper, we address these issues by combining QM/MM modeling with the methodology of "bottom-up" coarse-graining (CG) to provide the theoretical basis for a systematic quantum-mechanical/coarse-grained molecular mechanics (QM/CG-MM) mixed resolution approach. A derivation of the method is presented based on a combination of statistical mechanics and quantum mechanics, leading to an equation for the effective Hamiltonian of the QM part, a central concept in the QM/CG-MM theory. A detailed analysis of different contributions to the effective Hamiltonian from electrostatic, induction, dispersion, and exchange interactions between the QM part and the surroundings is provided, serving as a foundation for a potential hierarchy of QM/CG-MM methods varying in their accuracy and computational cost. A relationship of the QM/CG-MM methodology to other mixed resolution approaches is also discussed.

Quantum mechanics/coarse-grained molecular mechanics (QM/CG-MM)

Science.gov (United States)

Sinitskiy, Anton V.; Voth, Gregory A.

2018-01-01

Numerous molecular systems, including solutions, proteins, and composite materials, can be modeled using mixed-resolution representations, of which the quantum mechanics/molecular mechanics (QM/MM) approach has become the most widely used. However, the QM/MM approach often faces a number of challenges, including the high cost of repetitive QM computations, the slow sampling even for the MM part in those cases where a system under investigation has a complex dynamics, and a difficulty in providing a simple, qualitative interpretation of numerical results in terms of the influence of the molecular environment upon the active QM region. In this paper, we address these issues by combining QM/MM modeling with the methodology of "bottom-up" coarse-graining (CG) to provide the theoretical basis for a systematic quantum-mechanical/coarse-grained molecular mechanics (QM/CG-MM) mixed resolution approach. A derivation of the method is presented based on a combination of statistical mechanics and quantum mechanics, leading to an equation for the effective Hamiltonian of the QM part, a central concept in the QM/CG-MM theory. A detailed analysis of different contributions to the effective Hamiltonian from electrostatic, induction, dispersion, and exchange interactions between the QM part and the surroundings is provided, serving as a foundation for a potential hierarchy of QM/CG-MM methods varying in their accuracy and computational cost. A relationship of the QM/CG-MM methodology to other mixed resolution approaches is also discussed.

Prediction of the glyphosate sorption coefficient across two loamy agricultural fields

DEFF Research Database (Denmark)

Paradelo Pérez, Marcos; Norgaard, Trine; Moldrup, Per

2015-01-01

, suggesting that different properties control glyphosate sorption in different locations and at different scales of analysis. Better predictions were obtained for the best-four set for the field in Estrup (R2 = 0.87) and for both fields (R2 = 0.70), while the field in Silstrup showed a lower predictability (R......2 = 0.36). Possibly, the low predictability for the field in Silstrup originated from opposing gradients in clay and oxalate-extractable Fe across the field. Also, whereas a lower clay content in Estrup may be the limiting variable for glyphosate sorption, the field in Silstrup has a higher clay...... sorption coefficient, Kd, from easily measurable soil properties in two loamy, agricultural fields in Denmark: Estrup and Silstrup. Forty-five soil samples in Estrup and 65 in Silstrup were collected fromthe surface in a rectangular grid of 15 × 15-mfromeach field, and selected soil properties...

Residual sludge from dimensional stones: characterisation for their exploitation in civil and environmental applications

Science.gov (United States)

Antonella Dino, Giovanna; Clemente, Paolo; De Luca, Domenico Antonio; Lasagna, Manuela

2013-04-01

Residual sludge coming from dimensional stones working plants (diamond framesaw and ganguesaw with abrasive shots processes) represents a problem for Stone Industries. In fact the cost connected to their landfilling amounts to more than 3% of operating costs of dimensional stone working plants. Furthermore their strict feature as waste to dump (CER code 010413) contrasts the EU principles of "resource preservation" and "waste recovery". The main problems related to their management are: size distribution (fine materials, potentially asphyxial), presence of heavy metals (due to the working processes) and TPH content (due to oil machines losses). Residual sludge, considered according to Italian Legislative Decree n.152/06, can be used, as waste, for environmental restoration of derelict land or in cement plants. It is also possible to think about their systematic treatment in consortium plats for the production of Secondary Raw Materials (SRM) or "New Products" (NP, eg. artificial loam, waterproofing materials, ....). The research evidences that, on the basis of a correct sludge management, treatment and characterization, economic and environmental benefits are possible (NP or SRM in spite of waste to dump). To individuate different applications of residual sludge in civil and environmental contexts, a geotechnical (size distribution, permeability, Atterberg limits, cohesion and friction angle evaluation, Proctor soil test) characterization was foreseen. The geotechnical tests were conducted on sludge as such and on three different mixes: - Mix 1 - Bentonite clay (5-10%) added to sludge a.s (90-95%); - Mix 2 - Sludge a.s. (90-80-70%) added to coarse materials coming from crushed dimensional stones (10-20-30%); - Mix 3 - Sludge a.s. (50-70%) mixed with sand, compost, natural loam (50-30% mixture of sand, compost, natural loam). The results obtained from the four sets of tests were fundamental to evaluate: - the characteristics of the original materials; - the chance

Lectures on coarse geometry

CERN Document Server

Roe, John

2003-01-01

Coarse geometry is the study of spaces (particularly metric spaces) from a 'large scale' point of view, so that two spaces that look the same from a great distance are actually equivalent. This point of view is effective because it is often true that the relevant geometric properties of metric spaces are determined by their coarse geometry. Two examples of important uses of coarse geometry are Gromov's beautiful notion of a hyperbolic group and Mostow's proof of his famous rigidity theorem. The first few chapters of the book provide a general perspective on coarse structures. Even when only metric coarse structures are in view, the abstract framework brings the same simplification as does the passage from epsilons and deltas to open sets when speaking of continuity. The middle section reviews notions of negative curvature and rigidity. Modern interest in large scale geometry derives in large part from Mostow's rigidity theorem and from Gromov's subsequent 'large scale' rendition of the crucial properties of n...

Pore structure characteristics after two years biochar application to a sandy loam field

DEFF Research Database (Denmark)

Sun, Zhencai; Arthur, Emmanuel; de Jonge, Lis Wollesen

2015-01-01

the effects of birch wood biochar (20, 40, and 100 Mg ha−1) applied to a sandy loam on soil total porosity and pore structure indices. Bulk and intact soil samples were collected for physicochemical analyses and water retention and gas diffusivity measurements between pF 1.0 and pF 3.0. Biochar application...

Impact of Poultry Litter Cake, Cleanout, and Bedding following Chemical Amendments on Soil C and N Mineralization

OpenAIRE

Watts, Dexter B.; Smith, Katy E.; Torbert, H. A.

2012-01-01

Poultry litter is a great alternative N source for crop production. However, recent poultry litter management changes, and increased chemical amendment use may impact its N availability. Thus, research was initiated to evaluate the effect that broiler cake and total cleanout litter amended with chemical additives have on C and N mineralization. A 35-day incubation study was carried out on a Hartsells fine sandy loam (fine-loamy, siliceous, subactive, thermic Typic Hapludults) soil common to t...

A multiscale mortar multipoint flux mixed finite element method

KAUST Repository

Wheeler, Mary Fanett

2012-02-03

In this paper, we develop a multiscale mortar multipoint flux mixed finite element method for second order elliptic problems. The equations in the coarse elements (or subdomains) are discretized on a fine grid scale by a multipoint flux mixed finite element method that reduces to cell-centered finite differences on irregular grids. The subdomain grids do not have to match across the interfaces. Continuity of flux between coarse elements is imposed via a mortar finite element space on a coarse grid scale. With an appropriate choice of polynomial degree of the mortar space, we derive optimal order convergence on the fine scale for both the multiscale pressure and velocity, as well as the coarse scale mortar pressure. Some superconvergence results are also derived. The algebraic system is reduced via a non-overlapping domain decomposition to a coarse scale mortar interface problem that is solved using a multiscale flux basis. Numerical experiments are presented to confirm the theory and illustrate the efficiency and flexibility of the method. © EDP Sciences, SMAI, 2012.

Investigation of the transport of actinide-bearing soil colloids in the soil-aquatic environment

International Nuclear Information System (INIS)

Sheppard, J.C.; Campbell, M.J.; Kittrick, J.; Cheng, T.

1980-04-01

Uranium-233 particle size dependent distribution ratios for the 10 to 60 range were determined for muscatine silt loam, Burbank loamy sand, Ritzville silt loam, Fuquay sand, and Idaho sandy clay. A mathematical method for the analysis of centrifuge data was developed to determine particle size dependent distribution ratio for the 10 to 60 nm range. Comparison of the distribution ratio data for the 0 to 60 nm particle size range strongly suggests that particles in the 1 to 10 nm (8000 to 50,000 MW) range play a dominate role. Since these particles are probably humic acid polymers, future research should be focused on humic acid complexing of radionuclides. A mathematical analysis is given to demonstrate the role of humic acid complexing in the transport of radionuclides in the soil-aquatic environment

Power-Aware Rationale for Using Coarse-Grained Transponders in IP-Over-WDM Networks

DEFF Research Database (Denmark)

Saldaña Cercos, Silvia; Resendo, Leandro C.; Ribeiro, Moises R. N.

2015-01-01

.e., using 10 Gbps technology)? (2) What is the long-term cost of coarse-grained designs? We define a power-aware mixed integer linear programming (MILP) formulation based on actual modular architectures where modules are upgraded as the network traffic increases. We introduce, for the first time, important...

Geochemical assessment of application effectiveness of the loess-like loamy stratum for shielding phytotoxic mining rock in the Western Donets Basin

Directory of Open Access Journals (Sweden)

M. M. Kharitonov

2006-03-01

Full Text Available Main environmental threats of the excavated rocks and gobs in theWestern Donbassare pollution of soils and subterranean waters by toxic salts and heavy metals. Use of the three-layered models with a stratum of protective shield of the loess-like loamy soil for the restoration considerably decreases this negative impact.

Cadmium phytoextraction from loam soil in tropical southern China by Sorghum bicolor.

Science.gov (United States)

Wang, Xu; Chen, Can; Wang, Jianlong

2017-06-03

The cadmium (Cd) uptake characteristics by Sorghum bicolor cv. Nengsi 2# and Cowley from the acidic sandy loam soil (pH = 6.1) during the entire growth period (100 days) were investigated in pot outdoors in a tropical district of southern China, Hainan Island. The Cd-spiked levels in soil were set as 3 and 15 mg/kg. Correspondingly, the available Cd levels in soil extracted by Mehlich III solution were 2.71 and 9.41 mg/kg, respectively. Basically, two varieties in a full growth period (100 days) did not show a significant difference in their growth and Cd uptake. Under high Cd stress, the plant growth was inhibited and its biomass weight and height decreased by 38.7-51.5% and 27.6-28.5%, respectively. However, S. bicolor showed higher bioaccumulation capability of Cd from soil to plant [bioconcentration factor (BCF)>4], and higher transfer capability of Cd from roots to shoots [translocation factor (TF)>1] under high Cd stress; Cd contents in the roots, stems, and leaves of S. bicolor reached 43.79-46.07, 63.28-70.60, and 63.10-66.06 mg/kg, respectively. S. bicolor exhibited the potential phytoextraction capability for low or moderate Cd-contamination in acidic sandy loam soil.

Suitability of peanut residue as a nitrogen source for a rye cover crop

OpenAIRE

Balkcom,Kipling Shane; Wood,Charles Wesley; Adams,James Fredrick; Meso,Bernard

2007-01-01

Leguminous winter cover crops have been utilized in conservation systems to partially meet nitrogen (N) requirements of succeeding summer cash crops, but the potential of summer legumes to reduce N requirements of a winter annual grass, used as a cover crop, has not been extensively examined. This study assessed the N contribution of peanut (Arachis hypogaea L.) residues to a subsequent rye (Secale cereale L.) cover crop grown in a conservation system on a Dothan sandy loam (fine-loamy, kaoli...

Respirable dust and quartz exposure from three South African farms with sandy, sandy loam, and clay soils.

Science.gov (United States)

Swanepoel, Andrew J; Kromhout, Hans; Jinnah, Zubair A; Portengen, Lützen; Renton, Kevin; Gardiner, Kerry; Rees, David

2011-07-01

To quantify personal time-weighted average respirable dust and quartz exposure on a sandy, a sandy loam, and a clay soil farm in the Free State and North West provinces of South Africa and to ascertain whether soil type is a determinant of exposure to respirable quartz. Three farms, located in the Free State and North West provinces of South Africa, had their soil type confirmed as sandy, sandy loam, and clay; and, from these, a total of 298 respirable dust and respirable quartz measurements were collected between July 2006-November 2009 during periods of major farming operations. Values below the limit of detection (LOD) (22 μg · m(-3)) were estimated using multiple 'imputation'. Non-parametric tests were used to compare quartz exposure from the three different soil types. Exposure to respirable quartz occurred on all three farms with the highest individual concentration measured on the sandy soil farm (626 μg · m(-3)). Fifty-seven, 59, and 81% of the measurements on the sandy soil, sandy loam soil, and clay soil farm, respectively, exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 25 μg · m(-3). Twelve and 13% of respirable quartz concentrations exceeded 100 μg · m(-3) on the sandy soil and sandy loam soil farms, respectively, but none exceeded this level on the clay soil farm. The proportions of measurements >100 μg · m(-3) were not significantly different between the sandy and sandy loam soil farms ('prop.test'; P = 0.65), but both were significantly larger than for the clay soil farm ('prop.test'; P = 0.0001). The percentage of quartz in respirable dust was determined for all three farms using measurements > the limit of detection. Percentages ranged from 0.5 to 94.4% with no significant difference in the median quartz percentages across the three farms (Kruskal-Wallis test; P = 0.91). This study demonstrates that there is significant potential for over-exposure to respirable quartz in

Leaching of human pathogens in repacked soil lysimeters and contamination of potato tubers under subsurface drip irrigation in Denmark

DEFF Research Database (Denmark)

Forslund, Anita; Plauborg, Finn; Andersen, Mathias Neumann

2011-01-01

The risk for contamination of potatoes and groundwater through subsurface drip irrigation with low quality water was explored in 30 large-scale lysimeters containing repacked coarse sand and sandy loam soils. The human pathogens, Salmonella Senftenberg, Campylobacter jejuni and Escherichia coli O......, phage 28B was detected in low concentrations (2 pfu ml1) in leachate from both sandy loam soil and coarse sand lysimeters. After 27 days, phage 28B continued to be present in similar concentrations in leachate from lysimeters containing coarse sand, while no phage were found in lysimeters with sandy....... The findings of bacterial pathogens and phage 28 on all potato samples suggest that the main risk associated with subsurface drip irrigation with low quality water is faecal contamination of root crops, in particular those consumed raw....

Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

Science.gov (United States)

Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

2015-06-01

The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of the use of steelmaking slag as an aggregate in concrete mix: A factorial design approach

Directory of Open Access Journals (Sweden)

Aljbour Salah H.

2017-01-01

Full Text Available Slag is investigated towards its potential use as an aggregate in concrete mix production. Full factorial design methodology is applied to study the effect of two process input variables, namely: slag as coarse aggregate and slag as medium aggregate on the properties of concrete mix. Additionally, the interaction between input variables is also examined. Incorporating steel slag aggregate in the concrete mix affected its compressive strength. Enhanced compressive strength concrete mix was obtained with 70 wt.% coarse slag aggregate and 70 wt.% medium slag aggregate. Under these proportions, the 28-days compressive strength was higher than the 28-days compressive strength of a concrete mix prepared from normal aggregate. Strong interaction effect exists between slag aggregate size on the compressive strength at 7-days curing. Lower compressive strength for the concrete mix might be obtained if improper proportions of mixed medium and coarse slag aggregate were employed.

Mechanical Properties of Lightweight Concrete Using Recycled Cement-Sand Brick as Coarse Aggregates Replacement

Science.gov (United States)

Joohari, Ilya; Farhani Ishak, Nor; Amin, Norliyati Mohd

2018-03-01

This paper presents the result of replacing natural course aggregate with recycled cement-sand brick (CSB) towards the mechanical properties of concrete. Natural aggregates were used in this study as a control sample to compare with recycled coarse aggregates. This study was also carried to determine the optimum proportion of coarse aggregates replacement to produce lightweight concrete. Besides, this study was conducted to observe the crack and its behaviour development during the mechanical testing. Through this study, four types of concrete mixed were prepared, which were the control sample, 25%, 50% and 75% replacement of CSB. The test conducted to determine the effectiveness of recycled CSB as coarse aggregates replacement in this study were slump test, density measurement, compression test, and flexural test and. The strength of concrete was tested at 7 days and 28 days of curing. From the results obtained, the optimum proportion which produced the highest strength is 25% replacement of recycled CSB. The compressive and flexural strength has decreased by 10%-12% and 4%-34% respectively compared to the control sample. The presence of recycled coarse aggregates in sample has decreased the density of concrete by 0.8%-3% compared to the control sample.

Mixed Generalized Multiscale Finite Element Methods and Applications

KAUST Repository

Chung, Eric T.

2015-03-03

In this paper, we present a mixed generalized multiscale finite element method (GMsFEM) for solving flow in heterogeneous media. Our approach constructs multiscale basis functions following a GMsFEM framework and couples these basis functions using a mixed finite element method, which allows us to obtain a mass conservative velocity field. To construct multiscale basis functions for each coarse edge, we design a snapshot space that consists of fine-scale velocity fields supported in a union of two coarse regions that share the common interface. The snapshot vectors have zero Neumann boundary conditions on the outer boundaries, and we prescribe their values on the common interface. We describe several spectral decompositions in the snapshot space motivated by the analysis. In the paper, we also study oversampling approaches that enhance the accuracy of mixed GMsFEM. A main idea of oversampling techniques is to introduce a small dimensional snapshot space. We present numerical results for two-phase flow and transport, without updating basis functions in time. Our numerical results show that one can achieve good accuracy with a few basis functions per coarse edge if one selects appropriate offline spaces. © 2015 Society for Industrial and Applied Mathematics.

A multiscale mortar multipoint flux mixed finite element method

KAUST Repository

Wheeler, Mary Fanett; Xue, Guangri; Yotov, Ivan

2012-01-01

In this paper, we develop a multiscale mortar multipoint flux mixed finite element method for second order elliptic problems. The equations in the coarse elements (or subdomains) are discretized on a fine grid scale by a multipoint flux mixed finite

Microbial assimilation of ¹⁴C of ground and unground plant materials decomposing in a loamy sand and a clay soil

DEFF Research Database (Denmark)

Sørensen, P.; Ladd, J.N.; Amato, M.

1996-01-01

The influence of grinding plant materials on the microbial decomposition and the distribution of plant-derived carbon in soil was measured. Ground and unground, C-14-labelled subclover leaves (Trifolium subterraneum) were added to a loamy sand and clay soil and incubated for 42 d at 25 degrees C....

Crop residues as driver for N2O emissions from a sandy loam soil

DEFF Research Database (Denmark)

Pugesgaard, Siri; Petersen, Søren O.; Chirinda, Ngonidzashe

2017-01-01

-term experiment on a loamy sand soil at Foulum in Denmark. All cropping systems included winter wheat, a leguminous crop (faba bean or grass-clover), potato and spring barley grown in different 4-crop rotations varying in strategies for N supply (fertilizer/manure type and rate, use of catch crops and green......-N leaching losses ranged from 39 to 56 kg N ha−1 y−1 and were lowest in rotations with catch crops; leaching was not correlated with N surplus or N input in fertilizer or manure. Crop yields of the organic rotations were 25 to 37% lower than in identical conventional rotations. As a consequence, yield...

Biomass production and nitrogen accumulation in pea, oat, and vetch green manure mixtures

International Nuclear Information System (INIS)

Jannink, J.L.; Liebman, M.; Merrick, L.C.

1996-01-01

Interest in the use of green manures has revived because of their role in improving soil quality and their beneficial N and non-N rotation effects. This study evaluated biomass production, N content, radiation interception (RI), and radiation use efficiency (RUE) of pea (Pisum sativum L.), oat (Avena sativa L.), and hairy vetch (Vicia villosa Roth) mixtures. Treatments were a three-way factorial of pea genotype ('Century' vs 'Tipu'), pea planting density (90 vs 224 kg ha -1 ), and cropping mixture (solecropped pea vs pea planted with a mixture of oat and hairy vetch). A mixture of oat and vetch without pea was also planted. Treatments were planted in early June on a Caribou gravelly loam (coarse-loamy, mixed, frigid Typic Haplorthods) in Presque Isle, ME, in 1993 and 1994. Biomass production and radiation interception were measured by repeated sampling. Mixture biomass was affected by a year x pea density interaction: respective yields for mixtures containing low-density and high-density pea were 770 and 880 g m -2 in 1993 vs 820 and 730 g m -2 in 1994. Mixture N content paralleled biomass production and averaged 209 g m -2 across all treatments. While pea sole crops did not consistently produce biomass or N equal to three-species mixtures the two-species mixture of oat and vetch did, yielding 820 g m -2 of biomass and 21.7 g m -2 of N, averaged over the 2 yr. Multiple regression showed that 61% of the variability in mixture biomass production was accounted for by a combination of early-season pea RI and midseason total mixture RUE. Economic analyses showed that rotation including these green manures may be economically competitive with a conventional rotation of barley (Hordeum vulgare L.) undersown with clover (Trifolium spp.) in a potato (Solanum tuberosum L.) production system

How coarse is too coarse for salmon spawning substrates?

Science.gov (United States)

Wooster, J. K.; Riebe, C. S.; Ligon, F. K.; Overstreet, B. T.

2009-12-01

Populations of Pacific salmon species have declined sharply in many rivers of the western US. Reversing these declines is a top priority and expense of many river restoration projects. To help restore salmon populations, managers often inject gravel into rivers, to supplement spawning habitat that has been depleted by gravel mining and the effects of dams—which block sediment and thus impair habitat downstream by coarsening the bed where salmon historically spawned. However, there is little quantitative understanding nor a methodology for determining when a river bed has become too coarse for salmon spawning. Hence there is little scientific basis for selecting sites that would optimize the restoration benefits of gravel injection (e.g., sites where flow velocities are suitable but bed materials are too coarse for spawning). To develop a quantitative understanding of what makes river beds too coarse for salmon spawning, we studied redds and spawning use in a series of California and Washington rivers where salmon spawning ability appears to be affected by coarse bed material. Our working hypothesis is that for a given flow condition, there is a maximum “threshold” particle size that a salmon of a given size is able to excavate and/or move as she builds her redd. A second, related hypothesis is that spawning use should decrease and eventually become impossible with increasing percent coverage by immovable particles. To test these hypotheses, we quantified the sizes and spatial distributions of immovably coarse particles in a series of salmon redds in each river during the peak of spawning. We also quantified spawning use and how it relates to percent coverage by immovable particles. Results from our studies of fall-run chinook salmon (Oncorhynchus tshawytsha) in the Feather River suggest that immovable particle size varies as a function of flow velocity over the redd, implying that faster water helps fish move bigger particles. Our Feather River study also

Mobility of nanosized cerium dioxide and polymeric capsules in quartz and loamy sands saturated with model and natural groundwaters.

Science.gov (United States)

Petosa, Adamo Riccardo; Ohl, Carolin; Rajput, Faraz; Tufenkji, Nathalie

2013-10-01

The environmental and health risks posed by emerging engineered nanoparticles (ENPs) released into aquatic environments are largely dependent on their aggregation, transport, and deposition behavior. Herein, laboratory-scale columns were used to examine the mobility of polyacrylic acid (PAA)-coated cerium dioxide nanoparticles (nCeO2) and an analogous nanosized polymeric capsule (nCAP) in water saturated quartz sand or loamy sand. The influence of solution ionic strength (IS) and cation type (Na(+), Ca(2+), or Mg(2+)) on the transport potential of these ENPs was examined in both granular matrices and results were also compared to measurements obtained using a natural groundwater. ENP suspensions were characterized using dynamic light scattering and nanoparticle tracking analysis to establish aggregate size, and laser Doppler electrophoresis to determine ENP electrophoretic mobility. Regardless of IS, virtually all nCeO2 particles suspended in NaNO3 eluted from the quartz sand-packed columns. In contrast, heightened nCeO2 and nCAP particle retention and dynamic (time-dependent) transport behavior was observed with increasing concentrations of the divalent salts and in the presence of natural groundwater. Enhanced particle retention was also observed in loamy sand in comparison to the quartz sand, emphasizing the need to consider the nature of the aqueous matrix and granular medium in evaluating contamination risks associated with the release of ENPs in natural and engineered aquatic environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impact of tillage intensity on clay loam soil structure

DEFF Research Database (Denmark)

Daraghmeh, Omar; Petersen, Carsten; Munkholm, Lars Juhl

Soil structure and structural stability are key parameters in sustainable soil management and optimum cropping practices. Locally and temporally adapted precision tillage may improve crop performance while at the same time reduce environmental impacts. The main objective of this study...... was to improve the knowledge of precision tillage practices through characterizing the effect of varied tillage intensities on structural properties of a clay loam soil. A field experiment was conducted using a randomized complete block design with two main factors, i.e. operational speed (OS, 2 levels......) and rotovating speed (RS, 3 levels). The tillage was conducted using a PTO-driven rotovator equipped to measure angular velocity. The effect of traffic compaction, made directly after tillage, was measured on soil taken from wheel track (WT) compared with soil outside wheel track (NWT). Soil samples from 0-3 cm...

ASSIMILATION OF COARSE-SCALEDATAUSINGTHE ENSEMBLE KALMAN FILTER

KAUST Repository

Efendiev, Yalchin

2011-01-01

Reservoir data is usually scale dependent and exhibits multiscale features. In this paper we use the ensemble Kalman filter (EnKF) to integrate data at different spatial scales for estimating reservoir fine-scale characteristics. Relationships between the various scales is modeled via upscaling techniques. We propose two versions of the EnKF to assimilate the multiscale data, (i) where all the data are assimilated together and (ii) the data are assimilated sequentially in batches. Ensemble members obtained after assimilating one set of data are used as a prior to assimilate the next set of data. Both of these versions are easily implementable with any other upscaling which links the fine to the coarse scales. The numerical results with different methods are presented in a twin experiment setup using a two-dimensional, two-phase (oil and water) flow model. Results are shown with coarse-scale permeability and coarse-scale saturation data. They indicate that additional data provides better fine-scale estimates and fractional flow predictions. We observed that the two versions of the EnKF differed in their estimates when coarse-scale permeability is provided, whereas their results are similar when coarse-scale saturation is used. This behavior is thought to be due to the nonlinearity of the upscaling operator in the case of the former data. We also tested our procedures with various precisions of the coarse-scale data to account for the inexact relationship between the fine and coarse scale data. As expected, the results show that higher precision in the coarse-scale data yielded improved estimates. With better coarse-scale modeling and inversion techniques as more data at multiple coarse scales is made available, the proposed modification to the EnKF could be relevant in future studies.

Attachment of Escherichia coli and enterococci to particles in runoff.

Science.gov (United States)

Soupir, Michelle L; Mostaghimi, Saied; Dillaha, Theo

2010-01-01

Association of Escherichia coli and enterococci with particulates present in runoff from erodible soils has important implications for modeling the fate and transport of bacteria from agricultural sources and in the selection of management practices to reduce bacterial movement to surface waters. Three soils with different textures were collected from the Ap horizon (silty loam, silty clay loam, and loamy fine sand), placed in portable box plots, treated with standard cowpats, and placed under a rainfall simulator. Rainfall was applied to the plots until saturation-excess flow occurred for 30 min, and samples were collected 10, 20, and 30 min after initiation of the runoff event. The attachment of E. coli and enterococci to particles present in runoff was determined by a screen filtration and centrifugation procedure. Percentage of E. coli and enterococci attached to particulates in runoff ranged from 28 to 49%, with few statistically significant differences in attachment among the three soils. Similar partitioning release patterns were observed between E. coli and enterococci from the silty loam (r = 0.57) and silty clay loam soils (r = 0.60). At least 60% of all attached E. coli and enterococci were associated particles within an 8- to 62-microm particle size category. The results indicate that the majority of fecal bacteria attach to and are transported with manure colloids in sediment-laden flow regardless of the soil texture.

Coarse graining for synchronization in directed networks

Science.gov (United States)

Zeng, An; Lü, Linyuan

2011-05-01

Coarse-graining model is a promising way to analyze and visualize large-scale networks. The coarse-grained networks are required to preserve statistical properties as well as the dynamic behaviors of the initial networks. Some methods have been proposed and found effective in undirected networks, while the study on coarse-graining directed networks lacks of consideration. In this paper we proposed a path-based coarse-graining (PCG) method to coarse grain the directed networks. Performing the linear stability analysis of synchronization and numerical simulation of the Kuramoto model on four kinds of directed networks, including tree networks and variants of Barabási-Albert networks, Watts-Strogatz networks, and Erdös-Rényi networks, we find our method can effectively preserve the network synchronizability.

Continuous Production of Isomalto-oligosaccharides by Thermo-inactivated Cells of Aspergillus niger J2 with Coarse Perlite as an Immobilizing Material.

Science.gov (United States)

Huang, Zhihua; Li, Zhihong; Su, Yongjian; Zhu, Yongfeng; Zeng, Wei; Chen, Guiguang; Liang, Zhiqun

2018-02-13

The coarse perlite 40-80 mesh was selected as an immobilizing material and put into a packed bed reactor (PBR) to continuously convert maltose to isomalto-oligosaccharides (IMOs). The PBR was prepared by mixing the thermo-inactivated cells (TIC) from Aspergillus niger J2 strain with the coarse perlite, then the mixture was put into an overpressure-resistant column. Compared with diatomite 40-80 mesh and thin perlite 80-120 mesh in PBR, coarse perlite was chosen as the best filtration aid, when the ratio of coarse perlite versus TIC was 1:1. The thermal and pH stability of the free and immobilized TIC and the optimum conditions for the transglycosylation reactions were determined. The results show that approximately 75 and 82% and 87 and 91% of α-glucosidase activity were reserved for free and immobilized TIC at temperatures from 30 to 60 °C and pH from 3.00 to 7.00 for 12 h, respectively. With 30% malt syrup under the conditions of 50 °C and pH 4.00, a mini-scale packed bed reactor (Mi-PBR) and medium-scale packed bed reactor (Me-PBR) could continuously produce IMO over 25 and 34 days with the yield of effective IMO (eIMO) ≥ 35% and total IMO (tIMO) ≥ 50%, respectively. The strategy of mixing the coarse perlite with TIC in PBR is a novel approach to continuously produce IMO and has great application potential in industry.

Repeated Load Permanent Deformation Behavior of Mixes With and Wihtout Modified Bituments

Directory of Open Access Journals (Sweden)

Imran Hafeez

2011-01-01

Full Text Available Premature rutting in flexible pavement structure is being observed on most of the road network of Pakistan. It initiates primarily due to uncontrolled axle loading and high ambient temperatures. NHA (National Highway Authority, Pakistan has continuously been modifying aggregate gradations and penetration grade of bitumen, without any prior investigation of the mix behaviour under the prevailing axle load and environmental conditions of the country. A comprehensive laboratory investigation was carried out on six mixes ranging from finer to coarser. Specimens were subjected to cyclic loading on UTM-5P (Universal Testing Machine to study the resistance against permanent deformation of the mixes at 25, 40 and 550C. At low temperatures and stress levels, both coarse and fine graded mixes showed less accumulated strain, whereas at higher temperatures and stress levels, coarse graded mix with PMB (Polymer Modified Bitumen showed good resistance to permanent deformation.

Relating soil microbial activity to water content and tillage-induced differences in soil structure

DEFF Research Database (Denmark)

Schjønning, Per; Thomsen, Ingrid Kaag; Petersen, Søren O

2011-01-01

Several studies have identified optima in soil water content for aerobic microbial activity, and this has been ascribed to a balance between gas and solute diffusivity as limiting processes. We investigated the role of soil structure, as created by different tillage practices (moldboard ploughing......, MP, or shallow tillage, ST), in regulating net nitrification, applied here as an index of aerobic microbial activity. Intact soil cores were collected at 0–4 and 14–18 cm depth from a fine sandy (SAND) and a loamy (LOAM) soil. The cores were drained to one of seven matric potentials ranging from − 15...... content to a maximum and then decreased. This relationship was modelled with a second order polynomium. Model parameters did not show any tillage effect on the optimum water content, but the optimum coincided with a lower matric potential in ST (SAND: − 140 to –197 hPa; LOAM: − 37 to − 65 hPa) than in MP...

Non-Galerkin Coarse Grids for Algebraic Multigrid

Energy Technology Data Exchange (ETDEWEB)

Falgout, Robert D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schroder, Jacob B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2014-06-26

Algebraic multigrid (AMG) is a popular and effective solver for systems of linear equations that arise from discretized partial differential equations. And while AMG has been effectively implemented on large scale parallel machines, challenges remain, especially when moving to exascale. Particularly, stencil sizes (the number of nonzeros in a row) tend to increase further down in the coarse grid hierarchy, and this growth leads to more communication. Therefore, as problem size increases and the number of levels in the hierarchy grows, the overall efficiency of the parallel AMG method decreases, sometimes dramatically. This growth in stencil size is due to the standard Galerkin coarse grid operator, $P^T A P$, where $P$ is the prolongation (i.e., interpolation) operator. For example, the coarse grid stencil size for a simple three-dimensional (3D) seven-point finite differencing approximation to diffusion can increase into the thousands on present day machines, causing an associated increase in communication costs. We therefore consider algebraically truncating coarse grid stencils to obtain a non-Galerkin coarse grid. First, the sparsity pattern of the non-Galerkin coarse grid is determined by employing a heuristic minimal “safe” pattern together with strength-of-connection ideas. Second, the nonzero entries are determined by collapsing the stencils in the Galerkin operator using traditional AMG techniques. The result is a reduction in coarse grid stencil size, overall operator complexity, and parallel AMG solve phase times.

The water retention of a granite rock fragments in High Tatras stony soils

OpenAIRE

Novák, Viliam; Šurda, Peter

2010-01-01

The water retention capacity of coarse rock fragments is usually considered negligible. But the presence of rock fragments in a soil can play an important role in both water holding capacity and in hydraulic conductivity as well. This paper presents results of maximum water holding capacity measured in coarse rock fragments in the soil classified as cobbly sandy loam sampled at High Tatra mountains. It is shown, that those coarse rock (granite) fragments have the maximum retention capacity up...

Optimization of Packing Density of M30 Concrete With Steel Slag As Coarse Aggregate Using Fuzzy Logic

Directory of Open Access Journals (Sweden)

Arivoli M.

2017-09-01

Full Text Available Concrete plays a vital role in the design and construction of the infrastructure. To meet the global demand of concrete in future, it is becoming a challenging task to find suitable alternatives to natural aggregates. Steel slag is a by-product of steel making process. The steel slag aggregates are characterized by studying particle size and shape, physical and chemical properties, and mechanical properties as per IS: 2386-1963. The characterization study reveals the better performance of steel slag aggregate over natural coarse aggregate. M30 grade of concrete is designed and natural coarse aggregate is completely replaced by steel slag aggregate. Packing density of aggregates affects the characteristics of concrete. The present paper proposes a fuzzy system for concrete mix proportioning which increases the packing density. The proposed fuzzy system have four sub fuzzy system to arrive compressive strength, water cement ratio, ideal grading curve and free water content for concrete mix proportioning. The results show, the concrete mix proportion of the given fuzzy model agrees with IS method. The comparison of results shows that both proposed fuzzy system and IS method, there is a remarkable increase in compressive strength and bulk density, with increment in the percentage replacement of steel slag.

HIRENASD coarse unstructured

Data.gov (United States)

National Aeronautics and Space Administration — Unstructured HIRENASD mesh: - coarse size (5.7 million nodes, 14.4 million elements) - for node centered solvers - 01.06.2011 - caution: dimensions in mm

Land Resources Evaluation Of The Paleodarainage Delta In Western Desert Of Egypt Using Remote Sensing Data

International Nuclear Information System (INIS)

Afify, A.A.

2009-01-01

The study area was selected to represent the sediments of paleodrainage delta in the Western Desert of Egypt, covering about 15615653 feddans (6561199 hectares). The data of Landsat Enhanced Thematic Mapper (ETM) 2002 were used for delineating the physiographic units to be a base for the soil taxonomic units (all are hyperthermic). These taxonomic units were potentially evaluated for barley and wheat (grain crops), alfalfa (fodder crop), maize, sun flower and olives (oil seed crops). The illustrated flow of the paleodrainage delta starts from the south as undulating delta apex, which most probably was deposited by the paleodrainage from Eastern Desert through the different rock structures. This apex includes soils of Calcic Petrogypsids loamy skeletal, gypsic; Typic Clacigypsids, loamy skeletal, gypsic and Typic Calcigypsids, sandy skeletal, mixed. The unit is profitable for drip irrigated olives as moderately to marginally suitable and for quarrying Oligocene gravel. Gently undulating inter delta includes sediments that was most probably received by reworking and out washing the slopes of delta apex in relatively more recent fluvial eras. The soils are Typic Calcigypsids, fine loamy, mixed; Typic Calcigypsids, loamy skeletal, mixed and Typic Calcigypsids, sandy, mixed. This unit is profitable for drip irrigated olives as highly suitable and sprinkly irrigated alfalfa, maize and sun flower as marginally suitable. Gently undulating to almost flat inter delta is most probably received its sediments from the southern physiographic units by the paleodrainage erosion. The soils are Leptic Haplogypsids, fine loamy, mixed and Leptic Haplogypsid, sandy, mixed. This unit is profitable for drip irrigated olives as moderately suitable. In the middle front of this unit, a township is proposed to be constructed A I Qattara Town . Flat depressed pro delta includes interfered sediments of different paleodrainage eras being received medium soil matrix over relatively old sediments

Generalized coarse-grained Becker-Doering equations

International Nuclear Information System (INIS)

Bolton, Colin D; Wattis, Jonathan A D

2003-01-01

We present and apply a generalized coarse-graining method of reducing the Becker-Doering model; originally formulated to describe the stepwise aggregation and fragmentation of clusters during nucleation. Previous formulations of the coarse-graining procedure have allowed a temporal rescaling of the coarse-grained reaction rates; this is generalized to allow the rescaling to depend on cluster size. The form of this factor is derived for general reaction rates and general mesh function so that the steady-state solution is preserved; in the case of an even mesh function the kinetics can also be accurately reproduced. With a size-dependent mesh function the equilibrium solution and the form of convergence to this state are matched for a specific example. Finally we consider reaction rates relevant to the classical nucleation theory of spherical cluster growth, and numerically compare solutions of the full system to the generalized coarse-grained system in both constant monomer and constant mass formulations, demonstrating the accuracy of the method

Effects of turbulent hyporheic mixing on reach-scale solute transport

Science.gov (United States)

Roche, K. R.; Li, A.; Packman, A. I.

2017-12-01

Turbulence rapidly mixes solutes and fine particles into coarse-grained streambeds. Both hyporheic exchange rates and spatial variability of hyporheic mixing are known to be controlled by turbulence, but it is unclear how turbulent mixing influences mass transport at the scale of stream reaches. We used a process-based particle-tracking model to simulate local- and reach-scale solute transport for a coarse-bed stream. Two vertical mixing profiles, one with a smooth transition from in-stream to hyporheic transport conditions and a second with enhanced turbulent transport at the sediment-water interface, were fit to steady-state subsurface concentration profiles observed in laboratory experiments. The mixing profile with enhanced interfacial transport better matched the observed concentration profiles and overall mass retention in the streambed. The best-fit mixing profiles were then used to simulate upscaled solute transport in a stream. Enhanced mixing coupled in-stream and hyporheic solute transport, causing solutes exchanged into the shallow subsurface to have travel times similar to the water column. This extended the exponential region of the in-stream solute breakthrough curve, and delayed the onset of the heavy power-law tailing induced by deeper and slower hyporheic porewater velocities. Slopes of observed power-law tails were greater than those predicted from stochastic transport theory, and also changed in time. In addition, rapid hyporheic transport velocities truncated the hyporheic residence time distribution by causing mass to exit the stream reach via subsurface advection, yielding strong exponential tempering in the in-stream breakthrough curves at the timescale of advective hyporheic transport through the reach. These results show that strong turbulent mixing across the sediment-water interface violates the conventional separation of surface and subsurface flows used in current models for solute transport in rivers. Instead, the full distribution of

Coarse-mesh rebalancing acceleration for eigenvalue problems

International Nuclear Information System (INIS)

Asaoka, T.; Nakahara, Y.; Miyasaka, S.

1974-01-01

The coarse-mesh rebalance method is adopted for Monte Carlo schemes for aiming at accelerating the convergence of a source iteration process. At every completion of the Monte Carlo game for one batch of neutron histories, the scaling factor for the neutron flux is calculated to achieve the neutron balance in each coarse-mesh zone into which the total system is divided. This rebalance factor is multiplied to the weight of each fission source neutron in the coarse-mesh zone for playing the next Monte Carlo game. The numerical examples have shown that the coarse-mesh rebalance Monte Carlo calculation gives a good estimate of the eigenvalue already after several batches with a negligible extra computer time compared to the standard Monte Carlo. 5 references. (U.S.)

Combined mild soil washing and compost-assisted phytoremediation in treatment of silt loams contaminated with copper, nickel, and chromium.

Science.gov (United States)

Sung, Menghau; Lee, Chi-Yi; Lee, Suen-Zone

2011-06-15

A new soil remediation option, combining the soil washing process using pure water followed by the compost-assisted phytoextraction, is evaluated using silt loams contaminated with plating wastewater containing Cu, Ni, and Cr. Plants utilized in this study are the rapeseeds, sunflowers, tomatoes, and soapworts. Phytoextraction operation was carried out in pot experiments over a period of 4 months. Metal concentrations in roots and shoots of plants were analyzed upon completion of each pot experiment. Hypothesis testing was employed in assessing the significance of difference in the experimental data. Results indicated that the rapeseed, a hyperaccumulator, is most effective in extracting metals from the compost-amended silt loams. The fast-growing sunflowers and tomatoes are comparable to rapeseeds in accumulating metals despite their relatively low metal concentrations in tissues. Bioaccumulation coefficients obtained for all plants are less than one, indicating that phytostabilization rather than phytoextraction is the dominant mechanism at this simulated final-phase condition. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of heavy metal content and physico-chemical properties of soils in the vicinity of Tasik Chini, Pahang

International Nuclear Information System (INIS)

Sahibin Abdul Rahim; Muhd Barzani Gasim; Mohd Nizam Mohd Said; Wan Mohd Razi Idris; Azman Hashim; Sharilnizam Yusof; Masniyana Jamil

2008-01-01

This study was carried out to determine heavy metal content and physico-chemical properties of soils influencing heavy metal accumulation in some series surrounding the Chini Lakes. A total of 15 topsoil sample were collected randomly from 6 stations. The physical properties that were analyzed include particle size distribution and soil organic matter. Meanwhile, the chemical characteristics determined were pH, electrical conductivity and cation exchange capacity. It was found that heavy metal content of Cd, Cr, Cu, Co, Pb, Zn and Mn were low whereas Fe content was high. The textures of soil studied were clay, loamy sand, sandy loam, clay loam and silty clay loam. The mean of organic matter ranged from 2.68 to 11.46 %. The soil pH showed that the soil studied was acidic with values ranged between 3.36 to 3.72. The range of electrical conductivity mean was between 2150 μScm -1 to 2403 μScm -1 . Cation exchange capacity mean ranged from 2.85 until 8.59 cmol/ kg. Correlation analysis showed that there were positive and negative significant correlations between soils parameters heavy metal concentration. Analysis of variance (ANOVA) showed that there were significant differences in organic matter percentage, pH, cation exchange capacity and heavy metals except cadmium between sampling station. (author)

Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

Directory of Open Access Journals (Sweden)

F. Siddika

2012-06-01

Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

Durability and Shrinkage Characteristics of Self-Compacting Concretes Containing Recycled Coarse and/or Fine Aggregates

Directory of Open Access Journals (Sweden)

Mehmet Gesoglu

2015-01-01

Full Text Available This paper addresses durability and shrinkage performance of the self-compacting concretes (SCCs in which natural coarse aggregate (NCA and/or natural fine aggregate (NFA were replaced by recycled coarse aggregate (RCA and/or recycled fine aggregate (RFA, respectively. A total of 16 SCCs were produced and classified into four series, each of which included four mixes designed with two water to binder (w/b ratios of 0.3 and 0.43 and two silica fume replacement levels of 0 and 10%. Durability properties of SCCs were tested for rapid chloride penetration, water sorptivity, gas permeability, and water permeability at 56 days. Also, drying shrinkage accompanied by the water loss and restrained shrinkage of SCCs were monitored over 56 days of drying period. Test results revealed that incorporating recycled coarse and/or fine aggregates aggravated the durability properties of SCCs tested in this study. The drying shrinkage and restrained shrinkage cracking of recycled aggregate (RA concretes had significantly poorer performance than natural aggregate (NA concretes. The time of cracking greatly prolonged as the RAs were used along with the increase in water/binder ratio.

Fine and coarse elemental components in the urban aerosol of Sao Paulo, Brazil

International Nuclear Information System (INIS)

Boueres, L.C.S.; Orsini, C.M.Q.

1981-01-01

Using cascade impactor sampling and PIXE analysis we have measured particle size distributions for approximately 15 elements in the Sao Paulo urban atmosphere. These elements, in our case, may be classified, according to their occurrence in fine or coarse aerosol log-normal modes, into three groups: (a) soil dust reference elements (coarse particle mode): Ti, Si and Ca; (b) anthropogenic fine particle mode: Zn, Br and Pb; and (c) mixed bimodal elements: S, K, V, Cr, Mn, Ni, Cu and Fe. All of the soil dust reference elements show consistently the log-normal parameters MMAD approx. 5.5 μm and sigmasub(g) approx. 3.2 (mass median aerodynamic diameter and geometric standard deviation, respectively). Enrichment factor calculations for Ti, Si, Ca and K in the coarse particle fraction (> 2 μmad), relative to Fe and the standard crustal aerosol values of Lawson and Winchester, show that Ti and Si are mainly soil derived while Ca and K may have significant industrial components in this particle fraction (i.e. coarse mode). The fine mode parameters for the other elements show variations with element suggesting different air pollution sources (such as motor vehicles, resuspended dust, refuse burning, industrial activities, etc.) and/or different chemical pathways, which presumably could be identifiable. For example, the modal parameters for group (b) are: Zn, MMAD = 0.9 μm, sigmasub(g) = 2.2; Br, MMAD = 0.5 μm, sigmasub(g) = 4.0; Pb, MMAD = 0.6 μm, sigmasub(g) = 3.0; thus suggesting a common source (automotive) for Br and Pb, unrelated to the source of Zn (possibly refuse burning). (orig.)

Determination of Selenium Toxicity for Survival and Reproduction of Enchytraeid Worms in a Sandy Loam Soil

Science.gov (United States)

2016-07-01

LOAM SOIL ECBC-TR-1388 Roman G. Kuperman Ronald T. Checkai Michael Simini Carlton T. Phillips RESEARCH AND TECHNOLOGY DIRECTORATE Richard M...plastic wrap was stretched over the top of each container and secured with a rubber band. Three pinholes were made in the plastic wrap to 6...172–178. Glover, J.; Levander, O.; Parizek, J.; Vouk, V. Selenium. In Handbook on the Toxicology of Metals; Friberg, L., Norberg, G.F., Vouk, V.B

Learning to Play Efficient Coarse Correlated Equilibria

KAUST Repository

Borowski, Holly P.

2018-03-10

The majority of the distributed learning literature focuses on convergence to Nash equilibria. Coarse correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However, there are no existing distributed learning algorithms that converge to specific coarse correlated equilibria. In this paper, we provide one such algorithm, which guarantees that the agents’ collective joint strategy will constitute an efficient coarse correlated equilibrium with high probability. The key to attaining efficient correlated behavior through distributed learning involves incorporating a common random signal into the learning environment.

Characterization of coarse particulate matter in school gyms

International Nuclear Information System (INIS)

Branis, Martin; Safranek, Jiri

2011-01-01

We investigated the mass concentration, mineral composition and morphology of particles resuspended by children during scheduled physical education in urban, suburban and rural elementary school gyms in Prague (Czech Republic). Cascade impactors were deployed to sample the particulate matter. Two fractions of coarse particulate matter (PM 10-2.5 and PM 2.5-1.0 ) were characterized by gravimetry, energy dispersive X-ray spectrometry and scanning electron microscopy. Two indicators of human activity, the number of exercising children and the number of physical education hours, were also recorded. Lower mass concentrations of coarse particulate matter were recorded outdoors (average PM 10-2.5 4.1-7.4 μg m -3 and PM 2.5-1.0 2.0-3.3 μg m -3 ) than indoors (average PM 10-2.5 13.6-26.7 μg m -3 and PM 2.5-1.0 3.7-7.4 μg m -3 ). The indoor concentrations of coarse aerosol were elevated during days with scheduled physical education with an average indoor-outdoor (I/O) ratio of 2.5-16.3 for the PM 10-2.5 and 1.4-4.8 for the PM 2.5-1.0 values. Under extreme conditions, the I/O ratios reached 180 (PM 10-2.5 ) and 19.1 (PM 2.5-1.0 ). The multiple regression analysis based on the number of students and outdoor coarse PM as independent variables showed that the main predictor of the indoor coarse PM concentrations is the number of students in the gym. The effect of outdoor coarse PM was weak and inconsistent. The regression models for the three schools explained 60-70% of the particular dataset variability. X-ray spectrometry revealed 6 main groups of minerals contributing to resuspended indoor dust. The most abundant particles were those of crustal origin composed of Si, Al, O and Ca. Scanning electron microscopy showed that, in addition to numerous inorganic particles, various types of fibers and particularly skin scales make up the main part of the resuspended dust in the gyms. In conclusion, school gyms were found to be indoor microenvironments with high concentrations of

Quantum theory of multiscale coarse-graining.

Science.gov (United States)

Han, Yining; Jin, Jaehyeok; Wagner, Jacob W; Voth, Gregory A

2018-03-14

Coarse-grained (CG) models serve as a powerful tool to simulate molecular systems at much longer temporal and spatial scales. Previously, CG models and methods have been built upon classical statistical mechanics. The present paper develops a theory and numerical methodology for coarse-graining in quantum statistical mechanics, by generalizing the multiscale coarse-graining (MS-CG) method to quantum Boltzmann statistics. A rigorous derivation of the sufficient thermodynamic consistency condition is first presented via imaginary time Feynman path integrals. It identifies the optimal choice of CG action functional and effective quantum CG (qCG) force field to generate a quantum MS-CG (qMS-CG) description of the equilibrium system that is consistent with the quantum fine-grained model projected onto the CG variables. A variational principle then provides a class of algorithms for optimally approximating the qMS-CG force fields. Specifically, a variational method based on force matching, which was also adopted in the classical MS-CG theory, is generalized to quantum Boltzmann statistics. The qMS-CG numerical algorithms and practical issues in implementing this variational minimization procedure are also discussed. Then, two numerical examples are presented to demonstrate the method. Finally, as an alternative strategy, a quasi-classical approximation for the thermal density matrix expressed in the CG variables is derived. This approach provides an interesting physical picture for coarse-graining in quantum Boltzmann statistical mechanics in which the consistency with the quantum particle delocalization is obviously manifest, and it opens up an avenue for using path integral centroid-based effective classical force fields in a coarse-graining methodology.

Quantum theory of multiscale coarse-graining

Science.gov (United States)

Han, Yining; Jin, Jaehyeok; Wagner, Jacob W.; Voth, Gregory A.

2018-03-01

Coarse-grained (CG) models serve as a powerful tool to simulate molecular systems at much longer temporal and spatial scales. Previously, CG models and methods have been built upon classical statistical mechanics. The present paper develops a theory and numerical methodology for coarse-graining in quantum statistical mechanics, by generalizing the multiscale coarse-graining (MS-CG) method to quantum Boltzmann statistics. A rigorous derivation of the sufficient thermodynamic consistency condition is first presented via imaginary time Feynman path integrals. It identifies the optimal choice of CG action functional and effective quantum CG (qCG) force field to generate a quantum MS-CG (qMS-CG) description of the equilibrium system that is consistent with the quantum fine-grained model projected onto the CG variables. A variational principle then provides a class of algorithms for optimally approximating the qMS-CG force fields. Specifically, a variational method based on force matching, which was also adopted in the classical MS-CG theory, is generalized to quantum Boltzmann statistics. The qMS-CG numerical algorithms and practical issues in implementing this variational minimization procedure are also discussed. Then, two numerical examples are presented to demonstrate the method. Finally, as an alternative strategy, a quasi-classical approximation for the thermal density matrix expressed in the CG variables is derived. This approach provides an interesting physical picture for coarse-graining in quantum Boltzmann statistical mechanics in which the consistency with the quantum particle delocalization is obviously manifest, and it opens up an avenue for using path integral centroid-based effective classical force fields in a coarse-graining methodology.

Linear mixing model applied to AVHRR LAC data

Science.gov (United States)

Holben, Brent N.; Shimabukuro, Yosio E.

1993-01-01

A linear mixing model was applied to coarse spatial resolution data from the NOAA Advanced Very High Resolution Radiometer. The reflective component of the 3.55 - 3.93 microns channel was extracted and used with the two reflective channels 0.58 - 0.68 microns and 0.725 - 1.1 microns to run a Constraine Least Squares model to generate vegetation, soil, and shade fraction images for an area in the Western region of Brazil. The Landsat Thematic Mapper data covering the Emas National park region was used for estimating the spectral response of the mixture components and for evaluating the mixing model results. The fraction images were compared with an unsupervised classification derived from Landsat TM data acquired on the same day. The relationship between the fraction images and normalized difference vegetation index images show the potential of the unmixing techniques when using coarse resolution data for global studies.

Effect of fly ash on the strength of porous concrete using recycled coarse aggregate to replace low-quality natural coarse aggregate

Science.gov (United States)

Arifi, Eva; Cahya, Evi Nur; Christin Remayanti, N.

2017-09-01

The performance of porous concrete made of recycled coarse aggregate was investigated. Fly ash was used as cement partial replacement. In this study, the strength of recycled aggregate was coMPared to low quality natural coarse aggregate which has high water absorption. Compression strength and tensile splitting strength test were conducted to evaluate the performance of porous concrete using fly ash as cement replacement. Results have shown that the utilization of recycled coarse aggregate up to 75% to replace low quality natural coarse aggregate with high water absorption increases compressive strength and splitting tensile strength of porous concrete. Using fly ash up to 25% as cement replacement improves compressive strength and splitting tensile strength of porous concrete.

Crop uptake and leaching losses of 15N labelled fertilizer nitrogen in relation to waterlogging of clay and sandy loam soils

International Nuclear Information System (INIS)

Webster, C.P.; Belford, R.K.; Cannell, R.Q.

1986-01-01

Ammonium nitrate fertilizer, labelled with 15 N, was applied in spring to winter wheat growing in undisturbed monoliths of clay and sandy loam soil in lysimeters; the rates of application were respectively 95 and 102 kg N ha -1 in the spring of 1976 and 1975. Crops of winter wheat, oilseed rape, peas and barley grown in the following 5 or 6 years were treated with unlabelled nitrogen fertilizer at rates recommended for maximum yields. During each year of the experiments the lysimeters were divided into treatments which were either freely drained or subjected to periods of waterlogging. Another labelled nitrogen application was made in 1980 to a separate group of lysimeters with a clay soil and a winter wheat crop to study further the uptake of nitrogen fertilizer in relation to waterlogging. In the first growing season, shoots of the winter wheater at harvest contained 46 and 58% of the fertilizer nitrogen applied to the clay and sandy loam soils respectively. In the following year the crops contained a further 1-2% of the labelled fertilizer, and after 5 and 6 years the total recoveries of labelled fertilizer in the crops were 49 and 62% on the clay and sandy loam soils respectively. In the first winter after the labelled fertilizer was applied, less than 1% of the fertilizer was lost in the drainage water, and only about 2% of the total nitrogen (mainly nitrate) in the drainage water from both soils was derived from the fertilizer

Characterization of coarse particulate matter in school gyms

Energy Technology Data Exchange (ETDEWEB)

Branis, Martin, E-mail: branis@natur.cuni.cz [Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Prague (Czech Republic); Safranek, Jiri [Charles University in Prague, Faculty of Physical Education, Department of Outdoor Sports, Prague (Czech Republic)

2011-05-15

We investigated the mass concentration, mineral composition and morphology of particles resuspended by children during scheduled physical education in urban, suburban and rural elementary school gyms in Prague (Czech Republic). Cascade impactors were deployed to sample the particulate matter. Two fractions of coarse particulate matter (PM{sub 10-2.5} and PM{sub 2.5-1.0}) were characterized by gravimetry, energy dispersive X-ray spectrometry and scanning electron microscopy. Two indicators of human activity, the number of exercising children and the number of physical education hours, were also recorded. Lower mass concentrations of coarse particulate matter were recorded outdoors (average PM{sub 10-2.5} 4.1-7.4 {mu}g m{sup -3} and PM{sub 2.5-1.0} 2.0-3.3 {mu}g m{sup -3}) than indoors (average PM{sub 10-2.5} 13.6-26.7 {mu}g m{sup -3} and PM{sub 2.5-1.0} 3.7-7.4 {mu}g m{sup -3}). The indoor concentrations of coarse aerosol were elevated during days with scheduled physical education with an average indoor-outdoor (I/O) ratio of 2.5-16.3 for the PM{sub 10-2.5} and 1.4-4.8 for the PM{sub 2.5-1.0} values. Under extreme conditions, the I/O ratios reached 180 (PM{sub 10-2.5}) and 19.1 (PM{sub 2.5-1.0}). The multiple regression analysis based on the number of students and outdoor coarse PM as independent variables showed that the main predictor of the indoor coarse PM concentrations is the number of students in the gym. The effect of outdoor coarse PM was weak and inconsistent. The regression models for the three schools explained 60-70% of the particular dataset variability. X-ray spectrometry revealed 6 main groups of minerals contributing to resuspended indoor dust. The most abundant particles were those of crustal origin composed of Si, Al, O and Ca. Scanning electron microscopy showed that, in addition to numerous inorganic particles, various types of fibers and particularly skin scales make up the main part of the resuspended dust in the gyms. In conclusion, school

Control of starch content in potato

International Nuclear Information System (INIS)

Korshunov, A.V.; Filippova, G.I.; Gaitova, N.A.; Kutovenko, L.N.

2010-01-01

The physiological and biochemical changes and connections defining the starch accumulation in potato tubers are showed. Using the radioisotope C14O2 are analysed data on carbohydrates accumulation in leaves, speed of their movement in tubers, synthetic and decomposing enzyme activities in plant organs, the content of starch in tubers depending on the combination of fertilizers. The necessity for dose phosphorus application level not lower than nitrogen is reasoned. Recommendations on the optimal combination of macrofertilizers, ensuring compromise between yield and tuber starchiness for sod-podzoil sandy-loam and loamy, grey forest, peat, chernozem soils in dry-farming and irrigation are given [ru

Migration of Co and Cs radionuclides through a loam soil column

International Nuclear Information System (INIS)

Syed Hakimi Sakuma bin Syed Ahmad; Shimooka, K.

1990-01-01

A soil column experiment was conducted to determine the migration of Co and Cs radionuclides through a loam soil. The different migration rates of the radionuclides at low and high concentrations were determined at pH 7. Retardation factor (Rf) both the radionuclides at low and high concentrations were determined by fitting adsorbed concentration distribution equations to observed values. The calculation shows that the Rf1=500 and Rf2=3 for Co at high and low concentrations, respectively. For Cs, the Rf1=600 and Rf2=5 at high and low concentrations, respectively. The results shows that major portions of both the radionuclides were adsorbed onto the soil layer at the top by ion exchange mechanism which resulted in the high retardation factor values. Minor portions had migrated downwards as insoluble cations, pseudocolloids and very fine silt particles resulting in the low retardation factor

A study of concrete properties using phyllite as coarse aggregates

International Nuclear Information System (INIS)

Adom-Asamoah, Mark; Afrifa, Russell Owusu

2010-01-01

Nowadays, industrial activities generate a huge amount of waste. One such activity is underground mining which generates phyllite wastes that are recycled as coarse aggregates for use in concrete production. Aggregate use in concrete is dependent on availability. This paper reports of an experimental study on some of the physical and mechanical properties of phyllite aggregate concrete as compared to granite (conventional) aggregate concrete. The obtained physical and mechanical properties of both aggregates for specific gravity, water absorption (%), dry density, aggregate impact value (%), aggregate crushing value (%), 10% fines, elongation index (%), flakiness index (%) and Los Angeles abrasion values satisfied minimum requirements for aggregates suitable for concrete production. Five mixes of concrete mix proportions designated M1, M2, M3, M4 and M5 were cast using phyllite and granite aggregates. A total of 400 concrete cubes and 210 modulus of rupture beams were cast and cured by total submerging in water for ages 3, 7, 14, 28, 56, 90, 180 and 360 days before compression and bending tests were performed. The results show that the trends in the development of compressive and bending strengths of plain phyllite concrete were similar to those in granite (conventional) aggregate concrete. However the compressive and bending strengths of phyllite concrete mixes were on the average 15-20% lower than those of the corresponding granite concrete mixes at all ages. The same concrete mix proportions gave lower concrete classes for phyllite compared to granite with the exception of the lowest grade. This was probably because the flakiness and elongation properties coupled with reactive materials in phyllite aggregates affect the absorption and bond characteristics of its concrete.

Key parameters in testing biodegradation of bio-based materials in soil.

Science.gov (United States)

Briassoulis, D; Mistriotis, A

2018-05-05

Biodegradation of plastics in soil is currently tested by international standard testing methods (e.g. ISO 17556-12 or ASTM D5988-12). Although these testing methods have been developed for plastics, it has been shown in project KBBPPS that they can be extended also to lubricants with small modifications. Reproducibility is a critical issue regarding biodegradation tests in the laboratory. Among the main testing variables are the soil types and nutrients available (mainly nitrogen). For this reason, the effect of the soil type on the biodegradation rates of various bio-based materials (cellulose and lubricants) was tested for five different natural soil types (loam, loamy sand, clay, clay-loam, and silt-loam organic). It was shown that use of samples containing 1 g of C in a substrate of 300 g of soil with the addition of 0.1 g of N as nutrient strongly improves the reproducibility of the test making the results practically independent of the soil type with the exception of the organic soil. The sandy soil was found to need addition of higher amount of nutrients to exhibit similar biodegradation rates as those achieved with the other soil types. Therefore, natural soils can be used for Standard biodegradation tests of bio-based materials yielding reproducible results with the addition of appropriate nutrients. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preparation and characterization of bentonite clays mixture destined to the removal of heavy metals

International Nuclear Information System (INIS)

Almeida Neto, A.F. de; Silva, M.G.C. da

2009-01-01

In this work a mixture was prepared with 50% wt. of the Bofe and Verde-lodo clays. The characterization methods used they were: thermal analyses (TG and DTG), X-ray diffraction, fisissorption of N 2 , scanning electron microscopy and X-ray energy dispersive spectroscopy. The rehearsals of adsorption we accomplished in system of finite bath using as adsorbent the mixture loamy in natura or it mixes calcined. Starting from TG and DTG a thermal treatment was accomplished to 500 deg C of the loamy mixture. Through the results of the copper adsorption, it was verified that mixes loamy it provokes chemical precipitation of the copper while the calcined sample presents amount metal adsorbed around 7.31 mg of copper/g of adsorbent. The value of removal percentage obtained by the calcined sample it was of 63.02%. (author)

Preparation and characterization of bentonite clays mixture destined to the removal of heavy metals; Preparacao e caracterizacao da mistura de argilas bentoniticas destinadas a remocao de metais pesados

Energy Technology Data Exchange (ETDEWEB)

Almeida Neto, A.F. de; Silva, M.G.C. da, E-mail: ambrosio@feq.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica. Dept. de Termofluidodinamica

2009-07-01

In this work a mixture was prepared with 50% wt. of the Bofe and Verde-lodo clays. The characterization methods used they were: thermal analyses (TG and DTG), X-ray diffraction, fisissorption of N{sub 2}, scanning electron microscopy and X-ray energy dispersive spectroscopy. The rehearsals of adsorption we accomplished in system of finite bath using as adsorbent the mixture loamy in natura or it mixes calcined. Starting from TG and DTG a thermal treatment was accomplished to 500 deg C of the loamy mixture. Through the results of the copper adsorption, it was verified that mixes loamy it provokes chemical precipitation of the copper while the calcined sample presents amount metal adsorbed around 7.31 mg of copper/g of adsorbent. The value of removal percentage obtained by the calcined sample it was of 63.02%. (author)

Simulation of gas mixing and transport in a multi-compartment geometry using the GOTHIC containment code and relatively coarse meshes

International Nuclear Information System (INIS)

Andreani, Michele; Paladino, Domenico

2010-01-01

The recently concluded OECD SETH project included twenty-four experiments on basic flows and gas transport and mixing driven by jets and plumes in two, large, connected vessels of the PANDA facility. The experiments featured injection of saturated or superheated steam, or a mixture of steam and helium in one vessel and venting from the same vessel or from the connected one. These tests have been especially designed for providing an extensive data base for the assessment of three-dimensional codes, including CFD codes. In particular, one of the goals of the analytical activities associated with the experiments was to evaluate the detail of the model (mesh) necessary for capturing the various phenomena. This work reports an overview of the results obtained for these experimental data using the advanced containment code GOTHIC and relatively coarse meshes, which are coarser than the ones typically used for the simulation with commercial CFD codes, but are still representative of the models which are currently affordable for a full containment analysis. In general, the phenomena were correctly represented in the simulations with GOTHIC, and the agreement of the results with the data was in most cases pretty good, in some cases excellent. Only for a few tests (or particular phenomena occurring in some tests) the simulations showed noticeable discrepancies with the experimental data, which could be referred to either an insufficiently detailed mesh or to lack of specialized models for local effects.

Physiographic soil map delineation for the Nile alluvium and desert outskirts in middle Egypt using remote sensing data of EgyptSat-1

Directory of Open Access Journals (Sweden)

A.A. Afify

2010-12-01

the River Nile course with courser sediments comparing to the recent alluvial plains. This belt is sub divided as levees that have soils of Typic Torriorthents, fine lomy; point bars with soils of Typic Torriorthents, coarse lomy; river banks with soils of Typic Torriorthents, coarse lomy; bow bars with Typic Torriorthents, sandy and Typic Torriorthents, coarse loamy and meander scars with soils of Typic Torriorthents, sandy. All these taxonomic classes are hyperthermic, being developed under the hyperthermic temperature regime within an aridic moisture regime.

Volatilization of gasoline from soil

International Nuclear Information System (INIS)

Arthus, P.

1993-05-01

Gasoline contaminated soil threatens water resources and air quality. The extent of the threat depends on gasoline behavior in soil, which is affected by various mechanisms such as volatilization. To quantify volatilization, gasoline spills were simulated in the laboratory using a synthetic gasoline and three dry soils. Total gasoline and individual gasoline compound concentrations in soil were monitored as a function of depth and time. The time to reduce overall gasoline concentration in coarse sand, sandy loam, and silt loam to 40% of initial concentration, averaged between surface and a 200-mm depth, ranged from 0.25 d to 10 d. A wicking phenomenon which contributed to gasoline flux toward the atmosphere was indicated by behavior of a low-volatility gasoline compound. Based on separate wicking experiments, this bulk immiscible movement was estimated at an upward velocity of 0.09 m/d for Delhi sandy loam and 0.05 m/d for Elora silt loam. 70 refs., 24 figs., 34 tabs

Structural-functional concept of thermophysical condition of the soils of Altai Region

Directory of Open Access Journals (Sweden)

Sergey Makarychev

2016-10-01

Full Text Available The goal of this study was to reveal the quantitative interrelations between the thermophysical indices (thermal conductivity and thermal diffusivity and physical soil properties such as; moisture content, density and detachability. According to the research targets, the soil samples including different genesis and soil particle size distribution were taken in different soil and climatic zones of the Altai Region. These were the sod-podzolic sandy loam soils of the dry steppes, chernozems and chestnut soils of light and medium loamy particle size distribution of temperately arid zone, and the heavy loamy gray forest soils and clayey chernozems of the Altai foothills and low mountains. The samples of undisturbed structures in different soil horizons were studied. To measure the thermophysical properties in laboratory setting, a pulse method of a two-dimensional heat source was used. The method takes into account the patterns of temperature field equalization in an unbounded medium after the heat source termination. A feature of this process is the occurrence of peak temperature at the investigated point of the medium at a given instant. The knowledge of this temperature and time enables to determine the soil thermal capacity, thermal conductivity and thermal diffusivity.

Degradation and persistence of cotton pesticides in sandy loam soils from Punjab, Pakistan.

Science.gov (United States)

Tariq, Muhammad Ilyas; Afzal, Shahzad; Hussain, Ishtiaq

2006-02-01

The present study evaluated the influence of temperature, moisture, and microbial activity on the degradation and persistence of commonly used cotton pesticides, i.e., carbosulfan, carbofuran, lambda-cyhalothrin, endosulfan, and monocrotophos, with the help of laboratory incubation and lysimeter studies on sandy loam soil (Typic Ustocurepts) in Pakistan. Drainage from the lysimeters was sampled on days 49, 52, 59, 73, 100, 113, and 119 against the pesticide application on days 37, 63, 82, 108, and 137 after the sowing of cotton. Carbofuran, monocrotophos, and nitrate were detected in the drainage samples, with an average value, respectively, of 2.34, 2.6 microg/L, and 15.6 mg/L for no-tillage and 2.16, 2.3 microg/L, and 13.4 mg/L for tillage. In the laboratory, pesticide disappearance kinetics were measured with sterile and nonsterile soils from 0 to 10 cm in depth at 15, 25, and 35 degrees C and 50% and 90% field water capacities. Monocrotophos and carbosulfan dissipation followed first-order kinetics while others followed second-order kinetics. The results of incubation studies showed that temperature and moisture contents significantly reduced the t(1/2) (half-life) values of pesticides in sterile and nonsterile soil, but the effect of microbial activity was nearly significant that might be due to less organic carbon (0.3%). The presence of carbofuran and monocrotophos in the soil profile (0-10, 10-30, 30-60, 60-90, 90-150 cm) and the higher concentrations of endosulfan and lambda-cyhalothrin in the top layer (0-10 cm) showed the persistence of the pesticides. The detection of endosulfan and lambda-cyhalothrin in the 10-30 cm soil layer might be due to preferential flow. The data generated from this study could be helpful for risk assessment studies of pesticides and for validating pesticide transport models for sandy loam soils in cotton-growing areas of Pakistan.

Influence of Root Exudates and Soil on Attachment of Pasteuria penetrans to Meloidogyne arenaria.

Science.gov (United States)

Liu, Chang; Timper, Patricia; Ji, Pingsheng; Mekete, Tesfamariam; Joseph, Soumi

2017-09-01

The bacterium Pasteuria penetrans is a parasite of root-knot nematodes ( Meloidogyne spp.). Endospores of P. penetrans attach to the cuticle of second-stage juveniles (J2) and subsequently sterilize infected females. When encumbered by large numbers of spores, juveniles are less mobile and their ability to infect roots is reduced. This study looked at different factors that influence spore attachment of P. penetrans to the root-knot nematode Meloidogyne arenaria . Pretreatment of J2 with root exudates of eggplant ( Solanum melongena cv. Black beauty) reduced spore attachment compared with pretreatment with phosphate-buffered saline (PBS), suggesting that the nematode surface coat was altered or the spore recognition domains on the nematode surface were blocked. Spore attachment was equally reduced following exposure to root exudates from both host and nonhost plants for M. arenaria , indicating a common signal that affects spore attachment. Although phytohormones have been shown to influence the lipophilicity of the nematode surface coat, auxins and kinetins did not affect spore attachment compared with PBS. Root exudates reduced spore attachment more in sterilized soil than in natural soil. Sterilization may have eliminated microbes that consume root exudates, or altered the chemical components of the soil solution or root exudates. Root exudates caused a greater decrease in spore attachment in loamy sand than in a sandy loam soil. The sandy loam had higher clay content than the loamy sand, which may have resulted in more adsorption of compounds in the root exudates that affect spore attachment. The components of the root exudates could have also been modified by soil type. The results of this study demonstrate that root exudates can decrease the attachment of P. penetrans endospores to root-knot nematodes, indicating that when these nematodes enter the root zone their susceptibility to spore attachment may decrease.

Lysimeter experiments to determine the ability of soil to reduce concentrations of BOD, available P and inorganic N in dirty water.

Science.gov (United States)

Brookman, S K E; Chadwick; Retter, A R

2005-11-01

Lysimeter experiments were conducted to determine the ability of different soils to reduce levels of biochemical oxygen demand (BOD) and concentrations of molybdate reactive phosphorus (MRP) and ammonium-N (NH4(+)-N) in dirty water and the impact of applications on nitrate leaching. An additional experiment investigated the effect of dirty water components on leaching quality. This information is required to assess the potential risk of dirty water applications on polluting groundwater and to assess the use of such soils in the development of treatment systems for dirty water. Intact and disturbed soil lysimeters, 0.5 and 1m deep were constructed from four soils; a coarse free-draining sandy loam, a sandy loam over soft sandstone, a calcareous silty clay over chalk and a sandy loam over granite. For the coarse free-draining sandy loam, lysimeters were also constructed from disturbed soil with and without the addition of lime, to assess if this could increase phosphorus immobilisation. Levels of BOD and concentrations of MRP, NH4(+)-N and nitrate (NO3(-)-N) of leachates were measured following dirty water applications at 2 and 8 mm day(-1) under laboratory conditions. Under the daily 2mm application, all soils were effective at treating dirty water, reducing concentrations of BOD, MRP and NH4(+)- N by > or = 98% but NO3(-)-N concentrations increased up to 80 mg l(-1) from the 0.5 m deep lysimeters of the sandy loam over granite. Soils were less effective at reducing levels of BOD, MRP and NH4(+)- N at the 8 mm daily rate of application, with maximum NO3(-)-N concentrations of leachates of 200 mg l(-1) from disturbed soils.

Effect of Fluoride and Bentonite on Biochemical Aspects of Oxidative Stress in Pisum sativum L.

Directory of Open Access Journals (Sweden)

Martyna Śnioszek

2018-03-01

Full Text Available Fluoride is regarded as one of the strongest oxidants, which causes oxidative changes in cells of living organisms. It may both increase the content of reactive oxygen species and inhibit the activity of antioxidative enzyme. In recent years, many researchers successfully used the properties of clay minerals in the sorption of fluoride ion from water. This raises the question of the possibility of limiting the effect of fluorine on the negative changes in plants by adding bentonite to soil. A two-year pot experiment was carried out in the Greenhouse of West Pomeranian University of Technology in Szczecin, on loamy sand and sandy loam. Each sample of soil was mixed with three different concentrations of bentonite – 1, 5, 10% of dry weight (DW of the soil and then treated with 30 mmol of F- per 1 kg of dry weight of the soil in a form of NaF solution. A control series was prepared for each soil, to which no additives were added. The medium prepared in such way was transferred to plastic pots (3 kg each and seeded with 16 pea seeds of Pisum sativum. In three phases of pea development (4 leaves unfolded, flowering and development of fruit, fresh leaf samples were collected and the concentrations of ascorbic acid, reduced glutathione, total flavonoids and total polyphenols were measured. Sodium fluoride introduced to the soil changed the level of antioxidant parameters in the plant, which may suggest that fluoride is involved in the formation of reactive oxygen species, resulting in oxidative stress. Bentonite in a dosage of 10% reduced the toxic effects of fluoride on the oxidative balance and morphological changes in the plant, which was observed especially for loamy sand, naturally poor in clay minerals.

Retention and loss of water extractable carbon in soils: effect of clay properties.

Science.gov (United States)

Nguyen, Trung-Ta; Marschner, Petra

2014-02-01

Clay sorption is important for organic carbon (C) sequestration in soils, but little is known about the effect of different clay properties on organic C sorption and release. To investigate the effect of clay content and properties on sorption, desorption and loss of water extractable organic C (WEOC), two experiments were conducted. In experiment 1, a loamy sand alone (native) or mixed with clay isolated from a surface or subsoil (78 and 96% clay) resulting in 90, 158 and 175 g clay kg(-1) soil. These soil treatments were leached with different WEOC concentrations, and then CO2 release was measured for 28 days followed by leaching with reverse osmosis water at the end of experiment. The second experiment was conducted to determine WEOC sorption and desorption of clays isolated from the loamy sand (native), surface soil and subsoil. Addition of clays isolated from surface and subsoil to sandy loam increased WEOC sorption and reduced C leaching and cumulative respiration in percentage of total organic C and WEOC added when expressed per g soil and per g clay. Compared to clays isolated from the surface and subsoil, the native clay had higher concentrations of illite and exchangeable Ca(2+), total organic C and a higher CEC but a lower extractable Fe/Al concentration. This indicates that compared to the clay isolated from the surface and the subsoil, the native clay had fewer potential WEOC binding sites because it had lower Fe/Al content thus lower number of binding sites and the existing binding sites are already occupied native organic matter. The results of this study suggest that in the soils used here, the impact of clay on WEOC sorption and loss is dependent on its indigenous organic carbon and Fe and/or Al concentrations whereas clay mineralogy, CEC, exchangeable Ca(2+) and surface area are less important. © 2013.

Upscaling the Use of Mixed Recycled Aggregates in Non-Structural Low Cement Concrete.

Science.gov (United States)

López-Uceda, Antonio; Ayuso, Jesús; Jiménez, José Ramón; Agrela, Francisco; Barbudo, Auxiliadora; De Brito, Jorge

2016-02-02

This research aims to produce non-structural concrete with mixed recycled aggregates (MRA) in upscaled applications with low-cement content. Four slabs were executed with concrete made with different ratios of coarse MRA (0%, 20%, 40% and 100%), using the mix design, the mixing procedures and the facilities from a nearby concrete production plant. The analysis of the long-term compressive and splitting tensile strengths in concrete cores, extracted from the slabs, allowed the highlighting of the long-term high strength development potential of MRA incorporation. The study of cast specimens produced in situ under the same conditions as the slabs showed, firstly, that the use of MRA has a great influence on the properties related to durability, secondly, that the loss of compressive strength for total MRA incorporation relative to control concrete increases proportionally with the class strength, and, thirdly, that the mechanical properties (including Schmidt hammer results) from the concrete slabs showed no significant differences relative to the control concrete for coarse aggregates replacements up to 40%. Therefore, this upscaled experimental study supports the application of concrete with 100% coarse MRA incorporation and low cement content in non-structural civil works such as bike lanes, gutters, ground slabs, leveling surfaces, and subgrades for foundations. To the best of the authors' knowledge, there have not been any upscaled applications of concrete with MRA and low cement content.

Upscaling the Use of Mixed Recycled Aggregates in Non-Structural Low Cement Concrete

Directory of Open Access Journals (Sweden)

Antonio López-Uceda

2016-02-01

Full Text Available This research aims to produce non-structural concrete with mixed recycled aggregates (MRA in upscaled applications with low-cement content. Four slabs were executed with concrete made with different ratios of coarse MRA (0%, 20%, 40% and 100%, using the mix design, the mixing procedures and the facilities from a nearby concrete production plant. The analysis of the long-term compressive and splitting tensile strengths in concrete cores, extracted from the slabs, allowed the highlighting of the long-term high strength development potential of MRA incorporation. The study of cast specimens produced in situ under the same conditions as the slabs showed, firstly, that the use of MRA has a great influence on the properties related to durability, secondly, that the loss of compressive strength for total MRA incorporation relative to control concrete increases proportionally with the class strength, and, thirdly, that the mechanical properties (including Schmidt hammer results from the concrete slabs showed no significant differences relative to the control concrete for coarse aggregates replacements up to 40%. Therefore, this upscaled experimental study supports the application of concrete with 100% coarse MRA incorporation and low cement content in non-structural civil works such as bike lanes, gutters, ground slabs, leveling surfaces, and subgrades for foundations. To the best of the authors’ knowledge, there have not been any upscaled applications of concrete with MRA and low cement content.

THE EFFECT OF SALINITY-SODICITY AND GLYPHOSATE FORMULATIONS – AVANS PREMIUM 360 SL ON PHOSPHOMONOESTERASE ACTIVITIES IN SANDY LOAM

Directory of Open Access Journals (Sweden)

Maciej Płatkowski

2016-01-01

Full Text Available The aim of study was to determine the influence of NaCl and glyphosate-based herbicide Avans Premium 360 SL on acid and alkaline phosphomonoesterase activities in sandy loam. The experiment was carried out in laboratory conditions on sandy loam with Corg content 10.90 g/kg. Soil was divided into half kilogram samples and adjusted to 60% of maximum water holding capacity. In the experiment dependent variables were: I – dosages of Avans Premium 360 SL (0, a recommended field dosage – FD, a tenfold higher dosage – 10 FD and hundredfold higher dosage – 100 FD, II – amount of NaCl (0, 3% and 6%, III – day of experiment (1, 7, 14, 28 and 56. On days of experiment the activity of alkaline and acid phosphomonoesterase activity was assayed spectrophotometrically. The obtained result showed that the application of Avans Premium 360 SL decreased in acid and alkaline phosphomonoesterase activity in clay soil. Significant interaction effect between the dosage of Avans Premium 360 SL, NaCl amount and day of experiment was reported in the experiment. The inhibitory effect of Avans Premium 360 SL was the highest in soil with NaCl at the amount of 6%.

Fine and Coarse-Scale Patterns of Vegetation Diversity on Reclaimed Surface Mine-land Over a 40-Year Chronosequence.

Science.gov (United States)

Bohrer, Stefanie L; Limb, Ryan F; Daigh, Aaron L; Volk, Jay M; Wick, Abbey F

2017-03-01

Rangelands are described as heterogeneous, due to patterning in species assemblages and productivity that arise from species dispersal and interactions with environmental gradients and disturbances across multiple scales. The objectives of rangeland reclamation are typically vegetation establishment, plant community productivity, and soil stability. However, while fine-scale diversity is often promoted through species-rich seed mixes, landscape heterogeneity and coarse-scale diversity are largely overlooked. Our objectives were to evaluate fine and coarse-scale vegetation patterns across a 40-year reclamation chronosequence on reclaimed surface coalmine lands. We hypothesized that both α-diversity and β-diversity would increase and community patch size and species dissimilarity to reference sites would decrease on independent sites over 40 years. Plant communities were surveyed on 19 post-coalmine reclaimed sites and four intact native reference sites in central North Dakota mixed-grass prairie. Our results showed no differences in α or β-diversity and plant community patch size over the 40-year chronosequence. However, both α-diversity and β-diversity on reclaimed sites was similar to reference sites. Native species establishment was limited due to the presence of non-native species such as Kentucky bluegrass (Poa pratensis) on both the reclaimed and reference sites. Species composition was different between reclaimed and reference sites and community dissimilarity increased on reclaimed sites over the 40-year chronosequence. Plant communities resulting from reclamation followed non-equilibrium succession, even with consistent seeds mixes established across all reclaimed years. This suggests post-reclamation management strategies influence species composition outcomes and land management strategies applied uniformly may not increase landscape-level diversity.

Coarse Thinking and Pricing a Financial Option

OpenAIRE

Siddiqi, Hammad

2009-01-01

Mullainathan et al [Quarterly Journal of Economics, May 2008] present a formalization of the concept of coarse thinking in the context of a model of persuasion. The essential idea behind coarse thinking is that people put situations into categories and the values assigned to attributes in a given situation are affected by the values of corresponding attributes in other co-categorized situations. We derive a new option pricing formula based on the assumption that the market consists of coars...

Property A and Coarse Embedding for Locally Compact Groups

DEFF Research Database (Denmark)

Li, Kang

property A. In a joint work with Knudby, we characterize the connected simple Lie groups with the discrete topology that have different approximation properties (see Article B). Moreover, we give a contractive Schur multiplier characterization of locally compact groups coarsely embeddable into Hilbert......In the study of the Novikov conjecture, property A and coarse embedding of metric spaces were introduced by Yu and Gromov, respectively. The main topic of the thesis is property A and coarse embedding for locally compact second countable groups. We prove that many of the results that are known...... to hold in the discrete setting, hold also in the locally compact setting.In a joint work with Deprez, we show that property A is equivalent to amenability at infinity and the strong Novikov conjecture is true for every locally compact group that embeds coarsely into a Hilbert space (see Article A...

Two-level method with coarse space size independent convergence

Energy Technology Data Exchange (ETDEWEB)

Vanek, P.; Brezina, M. [Univ. of Colorado, Denver, CO (United States); Tezaur, R.; Krizkova, J. [UWB, Plzen (Czech Republic)

1996-12-31

The basic disadvantage of the standard two-level method is the strong dependence of its convergence rate on the size of the coarse-level problem. In order to obtain the optimal convergence result, one is limited to using a coarse space which is only a few times smaller than the size of the fine-level one. Consequently, the asymptotic cost of the resulting method is the same as in the case of using a coarse-level solver for the original problem. Today`s two-level domain decomposition methods typically offer an improvement by yielding a rate of convergence which depends on the ratio of fine and coarse level only polylogarithmically. However, these methods require the use of local subdomain solvers for which straightforward application of iterative methods is problematic, while the usual application of direct solvers is expensive. We suggest a method diminishing significantly these difficulties.

Effect of Simulated Weathering and Aging of TNT in Amended Sandy Loam Soil on Toxicity to the Enchytraeid Worm, Enchytreaeus Crypticus

Science.gov (United States)

2006-05-01

high bioavailability of organic compounds. However, amended SSL soil was analyzed for presence of metabolic transformation products from nitroaromatic...Phillips, C.; Checkai, R. 1999. Comparison of malathion toxicity using enchytraeid reproduction test and earthworm toxicity test in different soil ...OF TNT IN AMENDED SANDY LOAM SOIL ON TOXICITY TO THE ENCHYTRAEID WORM, ENCHYTRAEUS CRYPTICUS Roman G. Kuperman Ronald T. Checkai Michael Simini

Degradation of roxarsone in a silt loam soil and its toxicity assessment.

Science.gov (United States)

Liang, Tengfang; Ke, Zhengchen; Chen, Qing; Liu, Li; Chen, Guowei

2014-10-01

The land application of poultry or swine litter, containing large amounts of roxarsone, causes serious arsenic pollution in soil. Understanding biotransformation process of roxarsone and its potential risks favors proper disposal of roxarsone-contaminated animal litter, yet remains not achieved. We report an experimental study of biotransformation process of roxarsone in a silt loam soil under various soil moisture and temperature conditions, and the toxicity of roxarsone and its products from degradation. Results showed that soil moisture and higher temperature promoted roxarsone degradation, associating with emergent pentavalent arsenic. Analysis of fluorescein diacetate (FDA) hydrolysis activity revealed that roxarsone does not exert acute toxic on soil microbes. With the release of inorganic arsenic, FDA hydrolysis activity was inhibited gradually, as evidenced by ecotoxicological assessment using Photobacterium leiognathi. The results shade new lights on the dynamic roxarsone biotransformation processes in soil, which is important for guiding appropriate disposal of poultry or swine litter in the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coarse-graining stochastic biochemical networks: adiabaticity and fast simulations

Energy Technology Data Exchange (ETDEWEB)

Nemenman, Ilya [Los Alamos National Laboratory; Sinitsyn, Nikolai [Los Alamos National Laboratory; Hengartner, Nick [Los Alamos National Laboratory

2008-01-01

We propose a universal approach for analysis and fast simulations of stiff stochastic biochemical kinetics networks, which rests on elimination of fast chemical species without a loss of information about mesoscoplc, non-Poissonian fluctuations of the slow ones. Our approach, which is similar to the Born-Oppenhelmer approximation in quantum mechanics, follows from the stochastic path Integral representation of the cumulant generating function of reaction events. In applications with a small number of chemIcal reactions, It produces analytical expressions for cumulants of chemical fluxes between the slow variables. This allows for a low-dimensional, Interpretable representation and can be used for coarse-grained numerical simulation schemes with a small computational complexity and yet high accuracy. As an example, we derive the coarse-grained description for a chain of biochemical reactions, and show that the coarse-grained and the microscopic simulations are in an agreement, but the coarse-gralned simulations are three orders of magnitude faster.

Dynamics in coarse-grained models for oligomer-grafted silica nanoparticles

KAUST Repository

Hong, Bingbing

2012-01-01

Coarse-grained models of poly(ethylene oxide) oligomer-grafted nanoparticles are established by matching their structural distribution functions to atomistic simulation data. Coarse-grained force fields for bulk oligomer chains show excellent transferability with respect to chain lengths and temperature, but structure and dynamics of grafted nanoparticle systems exhibit a strong dependence on the core-core interactions. This leads to poor transferability of the core potential to conditions different from the state point at which the potential was optimized. Remarkably, coarse graining of grafted nanoparticles can either accelerate or slowdown the core motions, depending on the length of the grafted chains. This stands in sharp contrast to linear polymer systems, for which coarse graining always accelerates the dynamics. Diffusivity data suggest that the grafting topology is one cause of slower motions of the cores for short-chain oligomer-grafted nanoparticles; an estimation based on transition-state theory shows the coarse-grained core-core potential also has a slowing-down effect on the nanoparticle organic hybrid materials motions; both effects diminish as grafted chains become longer. © 2012 American Institute of Physics.

An Apparatus for Bed Material Sediment Extraction From Coarse River Beds in Large Alluvial Rivers

Science.gov (United States)

Singer, M. B.; Adam, H.; Cooper, J.; Cepello, S.

2005-12-01

Grain size distributions of bed material sediment in large alluvial rivers are required in applications ranging from habitat mapping, calibration of sediment transport models, high resolution sediment routing, and testing of existing theories of longitudinal and cross steam sediment sorting. However, characterizing bed material sediment from coarse river beds is hampered by difficulties in sediment extraction, a challenge that is generally circumvented via pebble counts on point bars, even though it is unclear whether the bulk grain size distribution of bed sediments is well represented by pebble counts on bars. We have developed and tested a boat-based sampling apparatus and methodology for extracting bulk sediment from a wide range of riverbed materials. It involves the use of a 0.4 x 0.4 x 0.2 meter stainless steel toothed sampler, called the Cooper Scooper, which is deployed from and dragged downstream by the weight of a jet boat. The design is based on that of a river anchor such that a rotating center bar connected to a rope line in the boat aligns the sampler in the downstream direction, the teeth penetrate the bed surface, and the sampler digs into the bed. The sampler is fitted with lead weights to keep it from tipping over. The force of the sampler `biting' into the bed can be felt on the rope line held by a person in the boat at which point they let out slack. The boat then motors to the spot above the embedded sampler, which is hoisted to the water surface via a system of pulleys. The Cooper Scooper is then clipped into a winch and boom assembly by which it is brought aboard. This apparatus improves upon commonly used clamshell dredge samplers, which are unable to penetrate coarse or mixed bed surfaces. The Cooper Scooper, by contrast, extracts statistically representative bed material sediment samples of up to 30 kilograms. Not surprisingly, the sampler does not perform well in very coarse or armored beds (e.g. where surface material size is on the

Mixing time effects on the dispersion performance of adhesive mixtures for inhalation.

Directory of Open Access Journals (Sweden)

Floris Grasmeijer

Full Text Available This paper deals with the effects of mixing time on the homogeneity and dispersion performance of adhesive mixtures for inhalation. Interactions between these effects and the carrier size fraction, the type of drug and the inhalation flow rate were studied. Furthermore, it was examined whether or not changes in the dispersion performance as a result of prolonged mixing can be explained with a balance of three processes that occur during mixing, knowing drug redistribution over the lactose carrier; (de- agglomeration of the drug (and fine lactose particles; and compression of the drug particles onto the carrier surface. For this purpose, mixtures containing salmeterol xinafoate or fluticasone propionate were mixed for different periods of time with a fine or coarse crystalline lactose carrier in a Turbula mixer. Drug detachment experiments were performed using a classifier based inhaler at different flow rates. Scanning electron microscopy and laser diffraction techniques were used to measure drug distribution and agglomeration, whereas changes in the apparent solubility were measured as a means to monitor the degree of mechanical stress imparted on the drug particles. No clear trend between mixing time and content uniformity was observed. Quantitative and qualitative interactions between the effect of mixing time on drug detachment and the type of drug, the carrier size fraction and the flow rate were measured, which could be explained with the three processes mentioned. Generally, prolonged mixing caused drug detachment to decrease, with the strongest decline occurring in the first 120 minutes of mixing. For the most cohesive drug (salmeterol and the coarse carrier, agglomerate formation seemed to dominate the overall effect of mixing time at a low inhalation flow rate, causing drug detachment to increase with prolonged mixing. The optimal mixing time will thus depend on the formulation purpose and the choice for other, interacting variables.

Mixing Time Effects on the Dispersion Performance of Adhesive Mixtures for Inhalation

Science.gov (United States)

Grasmeijer, Floris; Hagedoorn, Paul; Frijlink, Henderik W.; de Boer, H. Anne

2013-01-01

This paper deals with the effects of mixing time on the homogeneity and dispersion performance of adhesive mixtures for inhalation. Interactions between these effects and the carrier size fraction, the type of drug and the inhalation flow rate were studied. Furthermore, it was examined whether or not changes in the dispersion performance as a result of prolonged mixing can be explained with a balance of three processes that occur during mixing, knowing drug redistribution over the lactose carrier; (de-) agglomeration of the drug (and fine lactose) particles; and compression of the drug particles onto the carrier surface. For this purpose, mixtures containing salmeterol xinafoate or fluticasone propionate were mixed for different periods of time with a fine or coarse crystalline lactose carrier in a Turbula mixer. Drug detachment experiments were performed using a classifier based inhaler at different flow rates. Scanning electron microscopy and laser diffraction techniques were used to measure drug distribution and agglomeration, whereas changes in the apparent solubility were measured as a means to monitor the degree of mechanical stress imparted on the drug particles. No clear trend between mixing time and content uniformity was observed. Quantitative and qualitative interactions between the effect of mixing time on drug detachment and the type of drug, the carrier size fraction and the flow rate were measured, which could be explained with the three processes mentioned. Generally, prolonged mixing caused drug detachment to decrease, with the strongest decline occurring in the first 120 minutes of mixing. For the most cohesive drug (salmeterol) and the coarse carrier, agglomerate formation seemed to dominate the overall effect of mixing time at a low inhalation flow rate, causing drug detachment to increase with prolonged mixing. The optimal mixing time will thus depend on the formulation purpose and the choice for other, interacting variables. PMID:23844256

Characterization of coarse particulate matter in school gyms.

Science.gov (United States)

Braniš, Martin; Šafránek, Jiří

2011-05-01

We investigated the mass concentration, mineral composition and morphology of particles resuspended by children during scheduled physical education in urban, suburban and rural elementary school gyms in Prague (Czech Republic). Cascade impactors were deployed to sample the particulate matter. Two fractions of coarse particulate matter (PM(10-2.5) and PM(2.5-1.0)) were characterized by gravimetry, energy dispersive X-ray spectrometry and scanning electron microscopy. Two indicators of human activity, the number of exercising children and the number of physical education hours, were also recorded. Lower mass concentrations of coarse particulate matter were recorded outdoors (average PM(10-2.5) 4.1-7.4 μg m(-3) and PM(2.5-1.0) 2.0-3.3 μg m(-3)) than indoors (average PM(10-2.5) 13.6-26.7 μg m(-3) and PM(2.5-1.0) 3.7-7.4 μg m(-3)). The indoor concentrations of coarse aerosol were elevated during days with scheduled physical education with an average indoor-outdoor (I/O) ratio of 2.5-16.3 for the PM(10-2.5) and 1.4-4.8 for the PM(2.5-1.0) values. Under extreme conditions, the I/O ratios reached 180 (PM(10-2.5)) and 19.1 (PM(2.5-1.0)). The multiple regression analysis based on the number of students and outdoor coarse PM as independent variables showed that the main predictor of the indoor coarse PM concentrations is the number of students in the gym. The effect of outdoor coarse PM was weak and inconsistent. The regression models for the three schools explained 60-70% of the particular dataset variability. X-ray spectrometry revealed 6 main groups of minerals contributing to resuspended indoor dust. The most abundant particles were those of crustal origin composed of Si, Al, O and Ca. Scanning electron microscopy showed that, in addition to numerous inorganic particles, various types of fibers and particularly skin scales make up the main part of the resuspended dust in the gyms. In conclusion, school gyms were found to be indoor microenvironments with high

Evaluation of the use of steelmaking slag as an aggregate in concrete mix: A factorial design approach

OpenAIRE

Aljbour Salah H.; Tarawneh Sultan A.; Al-Harahsheh Adnan M.

2017-01-01

Slag is investigated towards its potential use as an aggregate in concrete mix production. Full factorial design methodology is applied to study the effect of two process input variables, namely: slag as coarse aggregate and slag as medium aggregate on the properties of concrete mix. Additionally, the interaction between input variables is also examined. Incorporating steel slag aggregate in the concrete mix affected its compressive strength. Enhanced compressive strength concrete mix was obt...

Non-periodic molecular dynamics simulations of coarse grained lipid bilayer in water

DEFF Research Database (Denmark)

Kotsalis, E. M.; Hanasaki, I.; Walther, Jens Honore

2010-01-01

We present a multiscale algorithm that couples coarse grained molecular dynamics (CGMD) with continuum solver. The coupling requires the imposition of non-periodic boundary conditions on the coarse grained Molecular Dynamics which, when not properly enforced, may result in spurious fluctuations o...... in simulating more complex systems by performing a non-periodic Molecular Dynamics simulation of a DPPC lipid in liquid coarse grained water.......We present a multiscale algorithm that couples coarse grained molecular dynamics (CGMD) with continuum solver. The coupling requires the imposition of non-periodic boundary conditions on the coarse grained Molecular Dynamics which, when not properly enforced, may result in spurious fluctuations...... of the material properties of the system represented by CGMD. In this paper we extend a control algorithm originally developed for atomistic simulations [3], to conduct simulations involving coarse grained water molecules without periodic boundary conditions. We demonstrate the applicability of our method...

Ceramic ware waste as coarse aggregate for structural concrete production.

Science.gov (United States)

García-González, Julia; Rodríguez-Robles, Desirée; Juan-Valdés, Andrés; Morán-Del Pozo, Julia M; Guerra-Romero, M Ignacio

2015-01-01

The manufacture of any kind of product inevitably entails the production of waste. The quantity of waste generated by the ceramic industry, a very important sector in Spain, is between 5% and 8% of the final output and it is therefore necessary to find an effective waste recovery method. The aim of the study reported in the present article was to seek a sustainable means of managing waste from the ceramic industry through the incorporation of this type of waste in the total replacement of conventional aggregate (gravel) used in structural concrete. Having verified that the recycled ceramic aggregates met all the technical requirements imposed by current Spanish legislation, established in the Code on Structural Concrete (EHE-08), then it is prepared a control concrete mix and the recycled concrete mix using 100% recycled ceramic aggregate instead of coarse natural aggregate. The concretes obtained were subjected to the appropriate tests in order to conduct a comparison of their mechanical properties. The results show that the concretes made using ceramic sanitary ware aggregate possessed the same mechanical properties as those made with conventional aggregate. It is therefore possible to conclude that the reuse of recycled ceramic aggregate to produce recycled concrete is a feasible alternative for the sustainable management of this waste.

FROM ATOMISTIC TO SYSTEMATIC COARSE-GRAINED MODELS FOR MOLECULAR SYSTEMS

KAUST Repository

Harmandaris, Vagelis; Kalligiannaki, Evangelia; Katsoulakis, Markos; Plechac, Petr

2017-01-01

The development of systematic (rigorous) coarse-grained mesoscopic models for complex molecular systems is an intense research area. Here we first give an overview of methods for obtaining optimal parametrized coarse-grained models, starting from

Radionuclide content and hydrodynamic characterization of the area in the vicinity of the Centro Regional de Ciencias Nucleares

International Nuclear Information System (INIS)

Brandao, Yana B.; Borges, Edvane

2008-01-01

In order to comply with the Brazilian environmental laws, a survey of the radiation levels in the site of construction of the Centro Regional de Ciencias Nucleares (CRCN), in the urban area of Recife, state of Pernanbuco, Brazil, was conducted, for further assessment of the impact caused by the center activities. Concentration level of 238 U and 210 Po were determined in soil and water samples were in the vicinity of the CRCN. The 238 U content in soil samples varied from 7 to 44.4 Bq.kg -1 . For water samples, the measured values for 210 Po ranged from 12 to 19.6 mBq.L -1 . Soil samples were collected to determine the hydrodynamic characteristic of the area. In order to determine the soil-water retention curves, samples were collected from the surface and at depths of 20-25 cm, 40-45 cm, 60-65 cm, 80-85 cm and 100-105 cm. The results of soil-water retention curves showed that the soil of the center, compounded by various embankments, presented several textural classifications, which ranged from loam sandy, loamy sand, loam and sand clay earth within the same profile 0-100 cm. (author)

Modelling airborne dispersion of coarse particulate material

International Nuclear Information System (INIS)

Apsley, D.D.

1989-03-01

Methods of modelling the airborne dispersion and deposition of coarse particulates are presented, with the emphasis on the heavy particles identified as possible constituents of releases from damaged AGR fuel. The first part of this report establishes the physical characteristics of the irradiated particulate in airborne emissions from AGR stations. The second part is less specific and describes procedures for extending current dispersion/deposition models to incorporate a coarse particulate component: the adjustment to plume spread parameters, dispersion from elevated sources and dispersion in conjunction with building effects and plume rise. (author)

Recycled Coarse Aggregate Produced by Pulsed Discharge in Water

Science.gov (United States)

Namihira, Takao; Shigeishi, Mitsuhiro; Nakashima, Kazuyuki; Murakami, Akira; Kuroki, Kaori; Kiyan, Tsuyoshi; Tomoda, Yuichi; Sakugawa, Takashi; Katsuki, Sunao; Akiyama, Hidenori; Ohtsu, Masayasu

In Japan, the recycling ratio of concrete scraps has been kept over 98 % after the Law for the Recycling of Construction Materials was enforced in 2000. In the present, most of concrete scraps were recycled as the Lower Subbase Course Material. On the other hand, it is predicted to be difficult to keep this higher recycling ratio in the near future because concrete scraps increase rapidly and would reach to over 3 times of present situation in 2010. In addition, the demand of concrete scraps as the Lower Subbase Course Material has been decreased. Therefore, new way to reuse concrete scraps must be developed. Concrete scraps normally consist of 70 % of coarse aggregate, 19 % of water and 11 % of cement. To obtain the higher recycling ratio, the higher recycling ratio of coarse aggregate is desired. In this paper, a new method for recycling coarse aggregate from concrete scraps has been developed and demonstrated. The system includes a Marx generator and a point to hemisphere mesh electrode immersed in water. In the demonstration, the test piece of concrete scrap was located between the electrodes and was treated by the pulsed discharge. After discharge treatment of test piece, the recycling coarse aggregates were evaluated under JIS and TS and had enough quality for utilization as the coarse aggregate.

Coarse graining of atactic polystyrene and its derivatives

Science.gov (United States)

Agrawal, Anupriya; Perahia, Dvora; Grest, Gary S.

2014-03-01

Capturing large length scales in polymers and soft matter while retaining atomistic properties is imperative to computational studies of dynamic systems. Here we present a new methodology developing coarse-grain model based on atomistic simulation of atactic polystyrene (PS). Similar to previous work by Fritz et al., each monomer is described by two coarse grained beads. In contrast to this earlier work where intramolecular potentials were based on Monte Carlo simulation of both isotactic and syndiotactic single PS molecule to capture stereochemistry, we obtained intramolecular interactions from a single molecular dynamics simulation of an all-atom atactic PS melts. The non-bonded interactions are obtained using the iterative Boltzmann inversion (IBI) scheme. This methodology has been extended to coarse graining of poly-(t-butyl-styrene) (PtBS). An additional coarse-grained bead is used to describe the t-butyl group. Similar to the process for PS, the intramolecular interactions are obtained from a single all atom atactic melt simulation. Starting from the non-bonded interactions for PS, we show that the IBI method for the non-bonded interactions of PtBS converges relatively fast. A generalized scheme for substituted PS is currently in development. We would like to acknowledge Prof. Kurt Kremer for helpful discussions during this work.

Coarse-graining free theories with gauge symmetries: the linearized case

International Nuclear Information System (INIS)

Bahr, Benjamin; Dittrich, Bianca; He Song

2011-01-01

Discretizations of continuum theories often do not preserve the gauge symmetry content. This occurs in particular for diffeomorphism symmetry in general relativity, which leads to severe difficulties in both canonical and covariant quantization approaches. We discuss here the method of perfect actions, which attempts to restore gauge symmetries by mirroring exactly continuum physics on a lattice via a coarse graining process. Analytical results can only be obtained via a perturbative approach, for which we consider the first step, namely the coarse graining of the linearized theory. The linearized gauge symmetries are exact also in the discretized theory; hence, we develop a formalism to deal with gauge systems. Finally, we provide a discretization of linearized gravity as well as a coarse graining map and show that with this choice the three-dimensional (3D) linearized gravity action is invariant under coarse graining.

Technological possibilities for increasing coarse coal yield in the Staszic mine

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Major, M

1985-06-01

Experiments carried out in the Staszic underground black coal mine in Upper Silesia showed that there is a correlation of coarse coal yield and yield strength of shield supports used at longwall faces. The faces were equipped with Pioma 25-45, Fazos 15-31 and Fazos 19-32 shield supports, KWB 3RDU shearer loaders and Rybnik chain conveyors. Pressure of oil in water emulsion used in the Pioma 25/45 shield supports was reduced from the recommended 30 MPa to 15 MPa or to 10 MPa. Reducing emulsion pressure (and support yield strength) caused an increase in coarse coal yield. Coarse coal yield was also increased by use of Fazos 19/32 shield supports with reduced yield strength. During the tests coarse coal yield increased 1.68% and 2.65%. Test results are shown in 3 diagrams. Investigations carried out in the Staszic mine in 1983 showed that by optimizing yield strength of shield supports coarse coal yield could be increased 2 to 8%. 6 references.

Volume calculations of coarse woody debris; evaluation of coarse woody debris volume calculations and consequences for coarse woody debris volume estimates in forest reserves

NARCIS (Netherlands)

Wijdeven, S.M.J.; Vaessen, O.H.B.; Hees, van A.F.M.; Olsthoorn, A.F.M.

2005-01-01

Dead wood is recognized as one of the key indicators for sustainable forest management and biodiversity. Accurate assessments of dead wood volume are thus necessary. In this study New volume models were designed based on actual volume measurements of coarse woody debris. The New generic model

Spacetime coarse grainings in nonrelativistic quantum mechanics

International Nuclear Information System (INIS)

Hartle, J.B.

1991-01-01

Sum-over-histories generalizations of nonrelativistic quantum mechanics are explored in which probabilities are predicted, not just for alternatives defined on spacelike surfaces, but for alternatives defined by the behavior of spacetime histories with respect to spacetime regions. Closed, nonrelativistic systems are discussed whose histories are paths in a given configuration space. The action and the initial quantum state are assumed fixed and given. A formulation of quantum mechanics is used which assigns probabilities to members of sets of alternative coarse-grained histories of the system, that is, to the individual classes of a partition of its paths into exhaustive and exclusive classes. Probabilities are assigned to those sets which decohere, that is, whose probabilities are consistent with the sum rules of probability theory. Coarse graining by the behavior of paths with respect to regions of spacetime is described. For example, given a single region, the set of all paths may be partitioned into those which never pass through the region and those which pass through the region at least once. A sum-over-histories decoherence functional is defined for sets of alternative histories coarse-grained by spacetime regions. Techniques for the definition and effective computation of the relevant sums over histories by operator-product formulas are described and illustrated by examples. Methods based on Euclidean stochastic processes are also discussed and illustrated. Models of decoherence and measurement for spacetime coarse grainings are described. Issues of causality are investigated. Such spacetime generalizations of nonrelativistic quantum mechanics may be useful models for a generalized quantum mechanics of spacetime geometry

Constructing Optimal Coarse-Grained Sites of Huge Biomolecules by Fluctuation Maximization.

Science.gov (United States)

Li, Min; Zhang, John Zenghui; Xia, Fei

2016-04-12

Coarse-grained (CG) models are valuable tools for the study of functions of large biomolecules on large length and time scales. The definition of CG representations for huge biomolecules is always a formidable challenge. In this work, we propose a new method called fluctuation maximization coarse-graining (FM-CG) to construct the CG sites of biomolecules. The defined residual in FM-CG converges to a maximal value as the number of CG sites increases, allowing an optimal CG model to be rigorously defined on the basis of the maximum. More importantly, we developed a robust algorithm called stepwise local iterative optimization (SLIO) to accelerate the process of coarse-graining large biomolecules. By means of the efficient SLIO algorithm, the computational cost of coarse-graining large biomolecules is reduced to within the time scale of seconds, which is far lower than that of conventional simulated annealing. The coarse-graining of two huge systems, chaperonin GroEL and lengsin, indicates that our new methods can coarse-grain huge biomolecular systems with up to 10,000 residues within the time scale of minutes. The further parametrization of CG sites derived from FM-CG allows us to construct the corresponding CG models for studies of the functions of huge biomolecular systems.

EFFECT OF COMPLEX FERTILIZERS USED IN EARLY CROP POTATO CULTURE ON LOAMY SAND SOIL

Directory of Open Access Journals (Sweden)

Wanda Wadas

2015-03-01

Full Text Available To obtain a high tuber yield of early crop potato good conditions for plant growth must be ensured. Potato has a relatively shallow root system and requires significant nutrient inputs to maintain tuber productivity and quality. The paper presents the results of the research on the effect of complex fertilizers type NPK MgS with and without microelements from the nitrophoska (HydroComplex, Nitrophoska Blue Special and Viking 13 and the amophoska group (Polimag S, and single-nutrient fertilizers on the plant growth and tuber yield of very early potato cultivars (‘Aster’, ‘Fresco’, ‘Gloria’ on loamy sand soil. The field experiment was carried out in mideastern Poland (52°03'N, 22°33'E. Potatoes were harvested 75 days after planting (the end of June. The type of fertilizer (single-nutrient or complex fertilizer slightly affected the growth of potato plants. With the use of complex fertilizers, the assimilation leaf area and leaf area index (LAI were similar to the application of single-nutrient fertilizers. Of the examined complex fertilizers, Viking 13 (representing the nitrophoska group without microelements resulted in a smaller increase of assimilation leaf area in comparison with the cultivation without mineral fertilization. The type of fertilizer exerted a greater influence on the plant growth of ‘Aster’ (Poland than ‘Fresco’ (The Netherlands and ‘Gloria’ (Germany. The productive effects of complex fertilizers in early crop potato culture on loamy sand soil were comparable with single-nutrient fertilizers. The highest tuber yield was achieved with the application of Nitrophoska Blue Special (from the nitrophoska group with the lowest NNH4+ concentration; the total tuber yield was higher on average by 2.94 t*ha-1 (21.0% and the yield of marketable tuber fraction (diameter above 30 mm by 2.55 t*ha-1 (20.4% in comparison with the cultivation without mineral fertilization. Although the total tuber yield was a little

Entropies from Coarse-graining: Convex Polytopes vs. Ellipsoids

Directory of Open Access Journals (Sweden)

Nikos Kalogeropoulos

2015-09-01

Full Text Available We examine the Boltzmann/Gibbs/Shannon SBGS and the non-additive Havrda-Charvát/Daróczy/Cressie-Read/Tsallis Sq and the Kaniadakis κ-entropy Sκ from the viewpoint of coarse-graining, symplectic capacities and convexity. We argue that the functional form of such entropies can be ascribed to a discordance in phase-space coarse-graining between two generally different approaches: the Euclidean/Riemannian metric one that reflects independence and picks cubes as the fundamental cells in coarse-graining and the symplectic/canonical one that picks spheres/ellipsoids for this role. Our discussion is motivated by and confined to the behaviour of Hamiltonian systems of many degrees of freedom. We see that Dvoretzky’s theorem provides asymptotic estimates for the minimal dimension beyond which these two approaches are close to each other. We state and speculate about the role that dualities may play in this viewpoint.

Generalization of mixed multiscale finite element methods with applications

Energy Technology Data Exchange (ETDEWEB)

Lee, C S [Texas A & M Univ., College Station, TX (United States)

2016-08-01

Many science and engineering problems exhibit scale disparity and high contrast. The small scale features cannot be omitted in the physical models because they can affect the macroscopic behavior of the problems. However, resolving all the scales in these problems can be prohibitively expensive. As a consequence, some types of model reduction techniques are required to design efficient solution algorithms. For practical purpose, we are interested in mixed finite element problems as they produce solutions with certain conservative properties. Existing multiscale methods for such problems include the mixed multiscale finite element methods. We show that for complicated problems, the mixed multiscale finite element methods may not be able to produce reliable approximations. This motivates the need of enrichment for coarse spaces. Two enrichment approaches are proposed, one is based on generalized multiscale finte element metthods (GMsFEM), while the other is based on spectral element-based algebraic multigrid (rAMGe). The former one, which is called mixed GMsFEM, is developed for both Darcy’s flow and linear elasticity. Application of the algorithm in two-phase flow simulations are demonstrated. For linear elasticity, the algorithm is subtly modified due to the symmetry requirement of the stress tensor. The latter enrichment approach is based on rAMGe. The algorithm differs from GMsFEM in that both of the velocity and pressure spaces are coarsened. Due the multigrid nature of the algorithm, recursive application is available, which results in an efficient multilevel construction of the coarse spaces. Stability, convergence analysis, and exhaustive numerical experiments are carried out to validate the proposed enrichment approaches. iii

Influence of Long-term Application of Feedlot Manure Amendments on Water Repellency of a Clay Loam Soil.

Science.gov (United States)

Miller, Jim J; Beasley, Bruce W; Hazendonk, Paul; Drury, Craig F; Chanasyk, David S

2017-05-01

Long-term application of feedlot manure to cropland may increase the quantity of soil organic carbon (C) and change its quality, which may influence soil water repellency. The objective was to determine the influence of feedlot manure type (stockpiled vs. composted), bedding material (straw [ST] vs. woodchips [WD]), and application rate (13, 39, or 77 Mg ha) on repellency of a clay loam soil after 17 annual applications. The repellency was determined on all 14 treatments using the water repellency index ( index), the water drop penetration time (WDPT) method, and molarity of ethanol (MED) test. The C composition of particulate organic matter in soil of five selected treatments after 16 annual applications was also determined using C nuclear magnetic resonance-direct polarization with magic-angle spinning (NMR-DPMAS). Manure type had no significant ( > 0.05) effect on index and WDPT, and MED classification was similar. Mean index and WDPT values were significantly greater and MED classification more hydrophobic for WD than ST. Application rate had no effect on the index, but WDPT was significantly greater and MED classification more hydrophobic with increasing application rate. Strong ( > 0.7) but nonsignificant positive correlations were found between index and WDPT versus hydrophobic (alkyl + aromatic) C, lignin at 74 ppm (O-alkyl), and unspecified aromatic compounds at 144 ppm. Specific aromatic compounds also contributed more to repellency than alkyl, O-alkyl, and carbonyl compounds. Overall, all three methods consistently showed that repellency was greater for WD- than ST-amended clay loam soil, but manure type had no effect. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Bio solid Recycling To Enhance Carbon Sequestration In Mountainous Lebanese Conditions

International Nuclear Information System (INIS)

Attalah, T; Jamous, C; Debs, P.; Darwish, T.

2012-01-01

In Lebanon, the great majority of wastewater is dumped wildly into streams, wells or the sea. Eventually treated sludge will be produced across the country and disposed of, to a great extent, on land. This disposal obeys rules and regulations in most countries. In this work, on the results of the application of a biosolid on the carbon balance in two contrasting soils are reported. The biosolid that originated from a small plant treating domestic wastewaters did not contain high concentrations of heavy metals. Biosolids were applied in two levels (S1: 3.75 tons ha - 1 and S2: 7.50 tons ha - 1) to a loamy sand (Kfarhim) and acalcareous loam (Baakline). The incorporation in early October was immediately followed by the sowing of a barley cover crop. Sludges increased the barley production in the fast draining loamy sand only. In parallel, the in-situ decomposition studied during the rainy seasons gave a carbon loss of 21.8% (Baakline) and 29.1% (Kfarhim) of the initial sludge Cn. In the short-term, studies showed that 15 to 31% of the carbon of biosolids will remain in soils. This could significantly contribute to carbon sequestration, particularly in slow-draining soils. (author)

Renormalization and Coarse-graining of Loop Quantum Gravity

OpenAIRE

Charles, Christoph

2017-01-01

The continuum limit of loop quantum gravity is still an open problem. Indeed, no proper dynamics in known to start with and we still lack the mathematical tools to study its would-be continuum limit. In the present PhD dissertation, we will investigate some coarse-graining methods that should become helpful in this enterprise. We concentrate on two aspects of the theory's coarse-graining: finding natural large scale observables on one hand and studying how the dynamics of varying graphs could...

Influence of uncoated and coated plastic waste coarse aggregates to concrete compressive strength

OpenAIRE

Purnomo Heru; Pamudji Gandjar; Satim Madsuri

2017-01-01

The use of plastic waste as coarse aggregates in concrete is part of efforts to reduce environmental pollution. In one hand the use of plastic as aggregates can provide lighter weight of the concrete than concrete using natural aggregates, but on the other hand bond between plastic coarse aggregates and hard matrix give low concrete compressive strength. Improvement of the bond between plastic coarse aggregate and hard matrix through a sand coating to plastic coarse aggregate whole surface is...

Recent Development of Multigrid Algorithms for Mixed and Noncomforming Methods for Second Order Elliptical Problems

Science.gov (United States)

Chen, Zhangxin; Ewing, Richard E.

1996-01-01

Multigrid algorithms for nonconforming and mixed finite element methods for second order elliptic problems on triangular and rectangular finite elements are considered. The construction of several coarse-to-fine intergrid transfer operators for nonconforming multigrid algorithms is discussed. The equivalence between the nonconforming and mixed finite element methods with and without projection of the coefficient of the differential problems into finite element spaces is described.

Resolving Properties of Polymers and Nanoparticle Assembly through Coarse-Grained Computational Studies.

Energy Technology Data Exchange (ETDEWEB)

Grest, Gary S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

Coupled length and time scales determine the dynamic behavior of polymers and polymer nanocomposites and underlie their unique properties. To resolve the properties over large time and length scales it is imperative to develop coarse grained models which retain the atomistic specificity. Here we probe the degree of coarse graining required to simultaneously retain significant atomistic details a nd access large length and time scales. The degree of coarse graining in turn sets the minimum length scale instrumental in defining polymer properties and dynamics. Using polyethylene as a model system, we probe how the coarse - graining scale affects the measured dynamics with different number methylene group s per coarse - grained beads. Using these models we simulate polyethylene melts for times over 500 ms to study the viscoelastic properties of well - entangled polymer melts and large nanoparticle assembly as the nanoparticles are driven close enough to form nanostructures.

Characteristics of thin and coarse particulates of urban and natural brazilian aerosols

International Nuclear Information System (INIS)

Orsini, C.Q.; Tabacnics, M.H.; Artaxo, P.; Andrade, M.F.; Kerr, A.S.

1994-01-01

Thin and coarse particulate were sampled during the period 1982-1985 in a natural coastal forest (Jureia), and five urban-industrial regions (Vitoria, Salvador, Porto Alegre, Sao Paulo and Belo Horizonte). The time variation of the concentration in the air, and the relative elementary composition of the thin and coarse particulate, sampled by thin and Coarse Particulate Sampler (AFG), were determined by gravimetric method and PIXE analysis respectively. The results demonstrated that the ground dust and salt from the sea are unequivocally one of the largest sources of coarse particulate, and also the ground is a significant thin particulate source. 25 refs, 22 figs, 28 tabs. (L.C.J.A.)

Importance of Coarse Woody Debris to Avian Communities in Loblolly Pine Forests

Energy Technology Data Exchange (ETDEWEB)

Lohr, S.M.; Gauthreaux, S.A.; Kilgo, J.C.

2001-06-14

Investigates the importance of standing and down coarse woody debris to bird communities in loblolly pine forests, researchers compared breeding and nonbreeding responses of birds among two coarse woody debris removal and control treatments. Quantification of vegetation layers to determine their effects on the experimental outcome coarse woody debris removal had no effect on the nonbreeding bird community. Most breeding and nonbreeding species used habitats with sparse midstory and well-developed understory, where as sparse canopy cover and dense midstory were important to some nonbreeding species. Snag and down coarse woody debris practices that maintain a dense understory, sparse midstory and canopy will create favorable breeding habitat.

Coarse-graining using the relative entropy and simplex-based optimization methods in VOTCA

Science.gov (United States)

Rühle, Victor; Jochum, Mara; Koschke, Konstantin; Aluru, N. R.; Kremer, Kurt; Mashayak, S. Y.; Junghans, Christoph

2014-03-01

Coarse-grained (CG) simulations are an important tool to investigate systems on larger time and length scales. Several methods for systematic coarse-graining were developed, varying in complexity and the property of interest. Thus, the question arises which method best suits a specific class of system and desired application. The Versatile Object-oriented Toolkit for Coarse-graining Applications (VOTCA) provides a uniform platform for coarse-graining methods and allows for their direct comparison. We present recent advances of VOTCA, namely the implementation of the relative entropy method and downhill simplex optimization for coarse-graining. The methods are illustrated by coarse-graining SPC/E bulk water and a water-methanol mixture. Both CG models reproduce the pair distributions accurately. SYM is supported by AFOSR under grant 11157642 and by NSF under grant 1264282. CJ was supported in part by the NSF PHY11-25915 at KITP. K. Koschke acknowledges funding by the Nestle Research Center.

Design of low-power coarse-grained reconfigurable architectures

CERN Document Server

Kim, Yoonjin

2010-01-01

Coarse-grained reconfigurable architecture (CGRA) has emerged as a solution for flexible, application-specific optimization of embedded systems. Helping you understand the issues involved in designing and constructing embedded systems, Design of Low-Power Coarse-Grained Reconfigurable Architectures offers new frameworks for optimizing the architecture of components in embedded systems in order to decrease area and save power. Real application benchmarks and gate-level simulations substantiate these frameworks.The first half of the book explains how to reduce power in the configuration cache. T

Optimization of nanolime solvent for the consolidation of coarse porous limestone

Science.gov (United States)

Borsoi, Giovanni; Lubelli, Barbara; van Hees, Rob; Veiga, Rosário; Silva, António Santos

2016-09-01

The potentialities of nanomaterials for application in the field of conservation have been widely investigated in the last two decades. Among nanomaterials, nanolimes, i.e., dispersions of lime nanoparticles in alcohols are promising consolidating products for calcareous materials. Nanolimes are effective in recovering the very superficial loss of cohesion of decayed materials, but they do not always provide sufficient mass consolidation. This limitation is mainly related to the deposition of the nanoparticles nearby the surface of the material. Experimental research has been set up with the aim of improving the in-depth deposition of lime nanoparticles. Previous research by the authors has shown that nanolime deposition within a substrate can be controlled by adapting the nanolimes properties (kinetic stability and evaporation rate) to the moisture transport behavior of the substrate. Nanolime properties can be modified by the use of different solvents. In this research, nanolime dispersions have been further optimized for application on Maastricht limestone, a coarse porous limestone. Firstly, nanolimes were synthesized and dispersed in ethanol and/or water, both pure and mixed in different percentages. Subsequently, based on the kinetic stability of the nanolime dispersions, the most promising solvent mixtures were selected and applied on the limestone. The deposition of lime nanoparticles within the limestone was studied by phenolphthalein test, optical microscopy and scanning electron microscopy. The results confirm that nanolime dispersed in a mixture of ethanol (95 %) and water (5 %) can guarantee a better nanoparticles in-depth deposition within coarse porous substrates, when compared to dispersions in pure ethanol.

The fate of fresh and stored 15N-labelled sheep urine and urea applied to a sandy and a sandy loam soil using different application strategies

DEFF Research Database (Denmark)

Sørensen, P.; Jensen, E.S.

1996-01-01

The fate of nitrogen from N-15-labelled sheep urine and urea applied to two soils was studied under field conditions. Labelled and stored urine equivalent to 204 kg N ha(-1) was either incorporated in soil or applied to the soil surface prior to sowing of Italian ryegrass (Lolium multiflorum L...... and soil was not significantly different for incorporated urine and urea. Almost all the supplied labelled N was accounted for in soil and herbage in the sandy loam soil, whereas 33-34% of the labelled N was unaccounted for in the sandy soil. When the stored urine was applied to the soil surface, 20...... was applied to growing ryegrass at the sandy loam soil, the immobilization of urine-derived N was significantly reduced compared to application prior to sowing. The results indicated that the net mineralization of urine N was similar to that of urea in the sandy soil, but only about 75% of the urine N was net...

Cultivos de cobertura: efectos sobre la macroporosidad y la estabilidad estructural de un suelo franco-limoso Cover crops: effects on soil macroporosity and soil structural stability in a silt loam soil

Directory of Open Access Journals (Sweden)

María Florencia Varela

2011-07-01

Full Text Available Los suelos franco-limosos manejados con siembra directa a menudo poseen porosidad estructural baja e inestable. Con el objetivo de determinar la capacidad de los cultivos de cobertura (CC de mejorar la porosidad y estabilidad estructural de estos suelos se llevaron a cabo experimentos de campo y de invernáculo. Ambos tuvieron tratamientos con y sin CC (avena, Avena sativa L., en rotación con soja (Glicine max L. Merr.. Luego de los CC se midieron densidad aparente (DA, el índice de inestabilidad estructural (IE y en el ensayo de invernáculo además, se midió la evolución de la distribución de tamaño de poros (DTP. En ambos ensayos la introducción de CC no disminuyó la DA, aunque incrementó la estabilidad del suelo (PNo- till (NT silt loam topsoils have often a low and unstable structural porosity. The objective of this study was to determine the capability of cover crops (CC of improving the structural porosity and stability of silt loam soils under NT. Greenhouse and field experiments were carried out on a silt loam soil (Typic Argiudoll with and without CC (oat, Avena sativa L. in crop sequences with soybean (Glicine max L. Merr.. Soil bulk density (DA and aggregate instability index (IE were measured after the CC in both experiments. In the greenhouse experiment, soil pore size distribution (DTP was measured. The use of CC did not change DA, but soil IE was significantly lower in crop sequences with CC (P < 0.05 both under field and greenhouse conditions. Stability increases were likely due to the effect of CC residues and root mass. No differences in DTP were found between treatments, although a significant effect of sampling date was observed (P<0.05. Changes in DTP were due to significant increases in mesopore (517.5% and macropore (52.7% volumes. Such changes occurred in all the treatments, probably due to the soil wetting-drying cycles. The results found in this study agree with other studies carried out on silt loams in the

Short- and medium-term response to storms on three Mediterranean coarse-grained beaches

Science.gov (United States)

Grottoli, Edoardo; Bertoni, Duccio; Ciavola, Paolo

2017-10-01

The storm response of three Italian coarse-grained beaches was investigated to better understand the morphodynamics of coarse-clastic beaches in a microtidal context. Two of the studied sites are located on the eastern side of the country (Portonovo and Sirolo) and the third one (Marina di Pisa) is on the western side. Portonovo and Sirolo are mixed sand and gravel beaches where the storms approach from two main directions, SE and NE. Marina di Pisa is a coarse-grained, gravel-dominated beach, exposed to storms driven by SW winds. Gravel nourishments were undertaken in recent years on the three sites. Beach topography was monitored measuring the same network of cross sections at a monthly (i.e. short-term) to seasonal frequency (i.e. medium-term). Geomorphic changes were examined before and after storm occurrences by means of profile analyses and shoreline position evaluations. The beach orientation and the influence of hard structures are the main factors controlling the transport and accumulation of significant amount of sediments and the consequent high variability of beach morphology over the medium-term. For Marina di Pisa, storms tend to accumulate material towards the upper part of the beach with no shoreline rotation and no chance to recover the initial configuration. Sirolo and Portonovo showed a similar behaviour that is more typical of pocket beaches. Both beaches show shoreline rotation after storms in a clockwise or counter-clockwise direction according to the incoming wave direction. The wider and longer beach at Sirolo allows the accumulation of a thin layer of sediment during storms, rather than at Portonovo where, given its longshore and landward boundaries, the beach material tends to accumulate in greater thickness. After storms, Sirolo and especially Portonovo can quickly recover the initial beach configuration, as soon as another storm of comparable energy approaches from the opposite direction of the previous one. Large morphological

Sustainable normal and high strength recycled aggregate concretes using crushed tested cylinders as coarse aggregates

Directory of Open Access Journals (Sweden)

Bilal S. Hamad

2017-12-01

Full Text Available The paper reports on a research program that was designed at the American University of Beirut (AUB to investigate the fresh and hardened mechanical properties of a high performance concrete mix produced with partial or full substitution of crushed natural lime-stone aggregates with recycled aggregates from crushed tested cylinders in batching plants. Choosing crushed cylinders as source of recycling would result in reusing portion of the waste products of the concrete production industry. An extensive concrete batching and testing program was conducted to achieve two optimum normal and high strength concrete mixes. The variables were the nominal concrete strength (28 or 60 MPa and the percentage replacement of natural coarse aggregates with recycled aggregates from crushed tested cylinders (0, 20, 40, 60, 80, or 100%. Normal strength tested cylinders were used as source of the recycled aggregates for the normal strength concrete (NSC mix and high strength tested cylinders were used for the high strength concrete (HSC mix. Tests on the trial batches included plastic state slump and hardened state mechanical properties including cylinder compressive strength, cylinder splitting tensile strength, modulus of elasticity, and standard beams flexural strength. The results indicated no significant effect on the slump and around 10% average reduction in the hardened mechanical properties for both investigated levels of concrete compressive strength.

Evaluation of Colemanite Waste as Aggregate Hot Mix Asphalt Concrete

Directory of Open Access Journals (Sweden)

Nihat MOROVA

2015-09-01

Full Text Available In this study usability of waste colemanite which is obtained after cutting block colemanite for giving proper shape to blocks as an aggregate in hot mix asphalt. For this aim asphalt concrete samples were prepared with four different aggregate groups and optimum bitumen content was determined. First of all only limestone was used as an aggregate. After that, only colemanite aggregate was used with same aggregate gradation. Then, the next step of the study, Marshall samples were produced by changing coarse and fine aggregate gradation as limestone and colemanite and Marshall test were conducted. When evaluated the results samples which produced with only limestone aggregate gave the maximum Marshall Stability value. When handled other mixture groups (Only colemanite, colemanite as coarse aggregate-limestone as fine aggregate, colemanite as fine aggregate-limestone as coarse aggregate all groups were verified specification limits. As a result, especially in areas where there is widespread colemanite waste, if transportation costs did not exceed the cost of limestone, colemanite stone waste could be used instead of limestone in asphalt concrete mixtures as fine aggregate

Magma Mixing: Magmatic Enclaves in Morne Micotrin, Dominica

Science.gov (United States)

Hickernell, S.; Frey, H. M.; Manon, M. R. F.; Waters, L. E.

2017-12-01

Magmatic enclaves in volcanic rocks provide direct evidence of magma mingling/mixing within a magma reservoir and may reinvigorate the system and trigger eruption, as documented at the Soufriere Hills in Montserrat. Lava domes on the neighboring island of Dominica also contain multiple enclave populations and may be evidence for similar magma chamber processes. The central dome of Micotrin is at the head of the Roseau Valley, which was filled with 3 km3 of pyroclastic deposits from eruptions spanning 65 - 25 ka. There appear to be two distinct types of enclaves in the crystal-rich Micotrin andesites (60 wt% SiO2), fine-grained and coarse-grained. Fine-grained mafic enclaves (52 wt% SiO2) vary in size from 1 to 15 cm in diameter, whereas the coarse-grained enclaves are generally larger and range from 3-20 cm. Fine-grained enclaves are saturated in plag (35%) + opx (35%) + cpx (20%) + oxides (10%). Average pyroxenes are 0.01 to 0.02 cm in size, whereas plagioclase averages 0.05 cm and up to 0.1 cm. The texture of the fine-grained enclaves is cumulate-like, devoid of microlites and matrix glass. Coarse-grained enclaves lack cpx and have different modal abundances and textures: plag (75%) + opx (10%) + oxides (5%) + plag microlites (10%). Plagioclase are 0.1 cm in size and orthopyroxenes average 0.05 cm. The coarse-grained enclaves are highly vesicular, a notable difference from the host as well as the fine-grained enclaves. The boundaries of both the fine- and coarse-grained enclaves are quite sharp and distinct and there do not appear to be enclave minerals disaggregated in the host rock. Temperatures were determined by two oxides. The fine-grained enclaves had two populations of magnetite, yielding 847 + 21° and 920 + 17°C. The coarse-grained enclave was 890 + 42 °C, but the oxides were extensively exsolved. Plagioclase composition in both coarse and fine-grained samples was comparable, ranging from An50 to An80. Despite compositional similarity the textures of

Performance of Recycled Porous Hot Mix Asphalt with Gilsonite Additive

Directory of Open Access Journals (Sweden)

Ludfi Djakfar

2015-01-01

Full Text Available The objective of the study is to evaluate the performance of porous asphalt using waste recycled concrete material and explore the effect of adding Gilsonite to the mixture. As many as 90 Marshall specimens were prepared with varied asphalt content, percentage of Gilsonite as an additive, and proportioned recycled and virgin coarse aggregate. The test includes permeability capability and Marshall characteristics. The results showed that recycled concrete materials seem to have a potential use as aggregate in the hot mix asphalt, particularly on porous hot mix asphalt. Adding Gilsonite at ranges 8–10% improves the Marshall characteristic of the mix, particularly its stability, without decreasing significantly the permeability capability of the mix. The use of recycled materials tends to increase the asphalt content of the mix at about 1 to 2% higher. With stability reaching 750 kg, the hot mix recycled porous asphalt may be suitable for use in the local roads with medium vehicle load.

An Evaluation of Coarse-Grained Locking for Multicore Microkernels

OpenAIRE

Elphinstone, Kevin; Zarrabi, Amirreza; Danis, Adrian; Shen, Yanyan; Heiser, Gernot

2016-01-01

The trade-off between coarse- and fine-grained locking is a well understood issue in operating systems. Coarse-grained locking provides lower overhead under low contention, fine-grained locking provides higher scalability under contention, though at the expense of implementation complexity and re- duced best-case performance. We revisit this trade-off in the context of microkernels and tightly-coupled cores with shared caches and low inter-core migration latencies. We evaluate performance on ...

Experimental investigation of coarse particle conveying in pipes

Directory of Open Access Journals (Sweden)

Vlasak Pavel

2015-01-01

Full Text Available The advanced knowledge of particle-water mixture flow behaviour is important for safe, reliable, and economical design and operation of the freight pipelines. The effect of the mixture velocity and concentration on the coarse particle – water mixtures flow behaviour was experimentally investigated on an experimental pipe loop of inner diameter D = 100 mm with horizontal, vertical, and inclined pipe sections. Narrow particle size distribution basalt pebbles were used as model of coarse-grained solid particles. The radiometric method was used to measure particle concentration distribution in pipe cross-section. Mixture flow behaviour and particles motion along the pipe invert were studied in a pipe viewing section. The study revealed that the coarse particlewater mixtures in the horizontal and inclined pipe sections were significantly stratified. The particles moved principally in a layer close to the pipe invert. However, for higher and moderate flow velocities the particles moved also in the central part of the pipe cross-section, and particle saltation was found to be dominant mode of particle conveying.

A new depositional model for sand-rich loess on the Buckley Flats outwash plain, northwestern Lower Michigan

Science.gov (United States)

Nyland, Kelsey E.; Schaetzl, Randall J.; Ignatov, Anthony; Miller, Bradley A.

2018-04-01

Loess was first studied in Michigan on the Buckley Flats, where outwash, overlain by ≈70 cm of loamy sediment, was originally interpreted as loess mixed with underlying sands. This paper re-evaluates this landscape through a spatial analysis of data from auger samples and soil pits. To better estimate the loamy sediment's initial textures, we utilized "filtered" laser diffraction data, which remove much of the coarser sand data. Textures of filtered silt data for the loamy sediment are similar to loess. The siltiest soils are found in the low-relief, central part of the Flats. Spatial analyses revealed that many silt fractions are nearly uniformly distributed, suggesting that the loess was not derived from a single source. The previous depositional model for the loamy mantle relied on loessfall followed by pedoturbation, but does not explain (1) the variation in sand contents across the Flats, or (2) the abrupt contact below the loamy mantle. This contact suggests that the outwash was frozen when the sediments above were deposited. Deep gullies at the western margins of the Flats were likely cut as permafrost facilitated runoff. Our new model for the origin of the loamy mantle suggests that the sands on the uplands were generated from eroding gullies and saltated onto the uplands along with loess that fell more widely. Sands saltating to the west of the Flats may have entrained some silts, facilitating loessfall downwind. At most sites, the loamy mantle gets increasingly silty near the surface, suggesting that saltation ended before loess deposition.

Multiresolution Modeling of Semidilute Polymer Solutions: Coarse-Graining Using Wavelet-Accelerated Monte Carlo

Directory of Open Access Journals (Sweden)

Animesh Agarwal

2017-09-01

Full Text Available We present a hierarchical coarse-graining framework for modeling semidilute polymer solutions, based on the wavelet-accelerated Monte Carlo (WAMC method. This framework forms a hierarchy of resolutions to model polymers at length scales that cannot be reached via atomistic or even standard coarse-grained simulations. Previously, it was applied to simulations examining the structure of individual polymer chains in solution using up to four levels of coarse-graining (Ismail et al., J. Chem. Phys., 2005, 122, 234901 and Ismail et al., J. Chem. Phys., 2005, 122, 234902, recovering the correct scaling behavior in the coarse-grained representation. In the present work, we extend this method to the study of polymer solutions, deriving the bonded and non-bonded potentials between coarse-grained superatoms from the single chain statistics. A universal scaling function is obtained, which does not require recalculation of the potentials as the scale of the system is changed. To model semi-dilute polymer solutions, we assume the intermolecular potential between the coarse-grained beads to be equal to the non-bonded potential, which is a reasonable approximation in the case of semidilute systems. Thus, a minimal input of microscopic data is required for simulating the systems at the mesoscopic scale. We show that coarse-grained polymer solutions can reproduce results obtained from the more detailed atomistic system without a significant loss of accuracy.

Effects of a novel poly (AA-co-AAm)/AlZnFe₂O₄/potassium humate superabsorbent hydrogel nanocomposite on water retention of sandy loam soil and wheat seedling growth.

Science.gov (United States)

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-10-25

A novel poly(acrylic acid-co-acrylamide)AlZnFe₂O₄/potassium humate( )superabsorbent hydrogel nanocomposite (PHNC) was synthesized and its physical properties characterized using SEM, Energy Dispersive X-ray (EDX) and FTIR spectroscopic techniques. Air dried sandy loam soil was amended with 0.1 to 0.4 w/w% of PHNC to evaluate its soil moisture retention attributes. Effect of PHNC amendment on pH, electrical conductivity (EC), porosity, bulk density and hydraulic conductivity of sandy loam soil was also studied. The soil amendment with 0.1 to 0.4 w/w% of PHNC remarkably enhanced the moisture retention at field capacity as compared to the un-amended soils. Seed germination and seedling growth of wheat (Triticum aestivum L.) was considerably increased and a delay by 6-9 days in wilting of seedlings was observed in the soil amended with PHNC, resulting in improved wheat plant establishment and growth.

Progress Report on SAM Reduced-Order Model Development for Thermal Stratification and Mixing during Reactor Transients

Energy Technology Data Exchange (ETDEWEB)

Hu, R. [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-09-01

This report documents the initial progress on the reduced-order flow model developments in SAM for thermal stratification and mixing modeling. Two different modeling approaches are pursued. The first one is based on one-dimensional fluid equations with additional terms accounting for the thermal mixing from both flow circulations and turbulent mixing. The second approach is based on three-dimensional coarse-grid CFD approach, in which the full three-dimensional fluid conservation equations are modeled with closure models to account for the effects of turbulence.

Temperature and water pressure head effects on the degradation of the diketonitrile metabolite of isoxaflutole in a loamy soil under two tillage systems

Energy Technology Data Exchange (ETDEWEB)

Alletto, Lionel [Universite de Toulouse - Ecole d' ingenieurs de Purpan, Agronomy Department, 75, voie du TOEC BP 57 611, 31 076 Toulouse Cedex 3 (France); UMR 1091 INRA/AgroParisTech Environment and Arable Crops, Institut National de la Recherche Agronomique/Institut National des Sciences et Industries du Vivant et de l' Environnement, BP 01, 78 850 Thiverval-Grignon (France)], E-mail: lionel.alletto@purpan.fr; Benoit, Pierre [UMR 1091 INRA/AgroParisTech Environment and Arable Crops, Institut National de la Recherche Agronomique/Institut National des Sciences et Industries du Vivant et de l' Environnement, BP 01, 78 850 Thiverval-Grignon (France)], E-mail: benoit@grignon.inra.fr; Bergheaud, Valerie [UMR 1091 INRA/AgroParisTech Environment and Arable Crops, Institut National de la Recherche Agronomique/Institut National des Sciences et Industries du Vivant et de l' Environnement, BP 01, 78 850 Thiverval-Grignon (France)], E-mail: bergheau@grignon.inra.fr; Coquet, Yves [UMR 1091 INRA/AgroParisTech Environment and Arable Crops, Institut National de la Recherche Agronomique/Institut National des Sciences et Industries du Vivant et de l' Environnement, BP 01, 78 850 Thiverval-Grignon (France)], E-mail: Yves.Coquet@agroparistech.fr

2008-12-15

Laboratory studies were conducted to evaluate the effects of temperature and water pressure head on the degradation of the diketonitrile metabolite (DKN) of isoxaflutole during 84 d in samples collected in a loamy soil under conventional (CT) and conservation (MT) tillage systems. Soil temperature was the major factor controlling DKN degradation in the two tillage systems. The shortest half-lives (T{sub 1/2}) were measured in the seedbed samples under MT at 25 deg. C and -33 cm water pressure head. We found that mouldboard ploughing under CT was responsible for the spatial variability of herbicide degradation properties, whereas under MT herbicide degradation was associated to the vertical distribution of organic matter. - Tillage practices influence the spatial variability of diketonitrile degradation in soil and its sensitivity to pedoclimatic conditions.

Temperature and water pressure head effects on the degradation of the diketonitrile metabolite of isoxaflutole in a loamy soil under two tillage systems

International Nuclear Information System (INIS)

Alletto, Lionel; Benoit, Pierre; Bergheaud, Valerie; Coquet, Yves

2008-01-01

Laboratory studies were conducted to evaluate the effects of temperature and water pressure head on the degradation of the diketonitrile metabolite (DKN) of isoxaflutole during 84 d in samples collected in a loamy soil under conventional (CT) and conservation (MT) tillage systems. Soil temperature was the major factor controlling DKN degradation in the two tillage systems. The shortest half-lives (T 1/2 ) were measured in the seedbed samples under MT at 25 deg. C and -33 cm water pressure head. We found that mouldboard ploughing under CT was responsible for the spatial variability of herbicide degradation properties, whereas under MT herbicide degradation was associated to the vertical distribution of organic matter. - Tillage practices influence the spatial variability of diketonitrile degradation in soil and its sensitivity to pedoclimatic conditions

Assessment of microbial activity and biomass in different soils exposed to nicosulfuron

Directory of Open Access Journals (Sweden)

Ljiljana Šantrić

2014-09-01

Full Text Available The effects of the herbicide nicosulfuron on the abundance of cellulolytic and proteolytic microorganisms, activity of β-glucosidase and protease enzymes, and microbial phosphorus biomass were examined. A laboratory bioassay was set up on two types of agricultural soils differing in physicochemical properties. The following concentrations were tested: 0.3, 0.6, 3.0 and 30.0 mg a.i./kg of soil. Samples were collected 3, 7, 14, 30 and 45 days after treatment with nicosulfuron. The results showed that nicosulfuron significantly reduced the abundance of cellulolytic microorganisms in both soils, as well as microbial biomass phosphorus in sandy loam soil. The herbicide was found to stimulate β-glucosidase and protease activity in both types of soil and microbial biomass phosphorus in loamy soil. Proteolytic microorganisms remained unaffected by nicosulfuron.

Effect of organic fertilization of soil, differentiated over many years, on the utilization of 15N-labelled urea

International Nuclear Information System (INIS)

Markgraf, G.; Winterfeld, C.

1983-01-01

Topsoil from samples with different organic fertilization of a soil fertility experiment started in 1936 at the Thyrow experimental site of the Berlin Humboldt University Crop Production Department was used for a pot experiment to study the N utilization of equal amounts of mineral fertilizer N (1.380 mg N/pot in the form of 15 N-labelled urea with an N frequency of 50 +- 0.5 atom per cent). The results showed that combined application of mineral NPK fertilization and high amounts of farmyard manure over a period of about 40 years on deep-loam fallow soil-sandy-rusty soil (diluvial sand to loamy-sandy soil) will lead to better utilization of the applied urea N as well as to higher N availability from the N pool of the soil. (author)

Phenanthrene sorption on biochar-amended soils

DEFF Research Database (Denmark)

Kahawaththa Gamage, Inoka Damayanthi Kumari; Moldrup, Per; Paradelo Pérez, Marcos

2014-01-01

on their influences on the sorption of environmental contaminants. In a field-based study at two experimental sites in Denmark, we investigated the effect of birch wood-derived biochar (Skogans kol) on the sorption of phenanthrene in soils with different properties. The soil sorption coefficient, Kd (L kg-1......), of phenanthrene was measured on sandy loam and loamy sand soils which have received from zero up to 100 t ha-1 of biochar. Results show that birch wood biochar had a higher Kd compared to soils. Furthermore, the application of birch wood biochar enhanced the sorption of phenanthrene in agricultural soils...... carbon, while it negatively correlated with clay content. The results also revealed that biochar-mineral interactions play an important role in the sorption of phenanthrene in biochar-amended soil....

Thermodynamically consistent coarse graining of biocatalysts beyond Michaelis–Menten

Science.gov (United States)

Wachtel, Artur; Rao, Riccardo; Esposito, Massimiliano

2018-04-01

Starting from the detailed catalytic mechanism of a biocatalyst we provide a coarse-graining procedure which, by construction, is thermodynamically consistent. This procedure provides stoichiometries, reaction fluxes (rate laws), and reaction forces (Gibbs energies of reaction) for the coarse-grained level. It can treat active transporters and molecular machines, and thus extends the applicability of ideas that originated in enzyme kinetics. Our results lay the foundations for systematic studies of the thermodynamics of large-scale biochemical reaction networks. Moreover, we identify the conditions under which a relation between one-way fluxes and forces holds at the coarse-grained level as it holds at the detailed level. In doing so, we clarify the speculations and broad claims made in the literature about such a general flux–force relation. As a further consequence we show that, in contrast to common belief, the second law of thermodynamics does not require the currents and the forces of biochemical reaction networks to be always aligned.

Hybrid continuum-coarse-grained modeling of erythrocytes

Science.gov (United States)

Lyu, Jinming; Chen, Paul G.; Boedec, Gwenn; Leonetti, Marc; Jaeger, Marc

2018-06-01

The red blood cell (RBC) membrane is a composite structure, consisting of a phospholipid bilayer and an underlying membrane-associated cytoskeleton. Both continuum and particle-based coarse-grained RBC models make use of a set of vertices connected by edges to represent the RBC membrane, which can be seen as a triangular surface mesh for the former and a spring network for the latter. Here, we present a modeling approach combining an existing continuum vesicle model with a coarse-grained model for the cytoskeleton. Compared to other two-component approaches, our method relies on only one mesh, representing the cytoskeleton, whose velocity in the tangential direction of the membrane may be different from that of the lipid bilayer. The finitely extensible nonlinear elastic (FENE) spring force law in combination with a repulsive force defined as a power function (POW), called FENE-POW, is used to describe the elastic properties of the RBC membrane. The mechanical interaction between the lipid bilayer and the cytoskeleton is explicitly computed and incorporated into the vesicle model. Our model includes the fundamental mechanical properties of the RBC membrane, namely fluidity and bending rigidity of the lipid bilayer, and shear elasticity of the cytoskeleton while maintaining surface-area and volume conservation constraint. We present three simulation examples to demonstrate the effectiveness of this hybrid continuum-coarse-grained model for the study of RBCs in fluid flows.

The Martini Coarse-Grained Force Field

NARCIS (Netherlands)

Periole, X.; Marrink, S.J.; Monticelli, Luca; Salonen, Emppu

2013-01-01

The Martini force field is a coarse-grained force field suited for molecular dynamics simulations of biomolecular systems. The force field has been parameterized in a systematic way, based on the reproduction of partitioning free energies between polar and apolar phases of a large number of chemical

Quartz luminescence response to a mixed alpha-beta field: Investigations on Romanian loess

International Nuclear Information System (INIS)

Constantin, Daniela; Jain, Mayank; Murray, Andrew S.; Buylaert, Jan-Pieter; Timar-Gabor, Alida

2015-01-01

Previous SAR-OSL dating studies using quartz extracted from Romanian and Serbian loess samples report SAR-OSL dose–response curves on fine grained (4–11 μm) quartz that grow to much higher doses compared to those of coarse-grained (63–90, 90–125, 125–180 μm) quartz. Furthermore, quartz SAR-OSL laboratory dose response curves do not reflect the growth of the OSL signal in nature. A main difference in coarse- and fine-grained quartz dating lies in the alpha irradiation history, but the effect of mixed alpha-beta fields has so far received little attention. In the present study we investigate whether the alpha dose experienced by fine grains over geological cycles of irradiation and bleaching may have an effect on the saturation characteristics of the laboratory dose response. By applying time resolved optically stimulated luminescence we confirm that the OSL signals induced in quartz by alpha and beta radiation follow the same recombination path. We also show that a mixed alpha-beta dose response reproduces the beta dose response only up to about 800 Gy. Assuming an a-value of 0.04 we have shown that laboratory alpha and beta dose response curves overlap up to effective alpha doses of ∼50 Gy. Based on these results, we conclude that exposure of fine grains to alpha radiation during burial and transport cycles prior to deposition, as well exposure to the mixed radiation field experienced during burial are not responsible for the age discrepancies previously reported on fine and coarse grained quartz extracted from Romanian and Serbian loess. - Highlights: • Prior alpha irradiation history does not influence the laboratory beta growth curves. • Alpha and beta induced photon emissions in quartz follow the same recombination path. • Laboratory alpha and beta growth curves overlap up to total alpha doses of ∼1250 Gy. • Mixed alpha-beta growth curves reproduce the beta dose response curves up to ∼800 Gy. • Mixed radiation field is not

Coarse sediment oil persistence laboratory studies and model

International Nuclear Information System (INIS)

Humphrey, B.; Harper, J.R.

1993-01-01

To gain understanding of the factors which affect the fate of stranded oil on coarse sediment beaches, a series of oil penetration and tidal flushing experiments was conducted in columns containing sediments of two grain sizes: granules and pebbles. The experiments included changing oil properties by weathering and by emulsification. Factors examined included permeability, effective porosity, and residual capacity of the sediment for oil. The laboratory data provided input to an oil persistence model for coarse sediment beaches, and the model was modified on the basis of the new data. The permeability measurements suggest that the permeability of pebble/granule mixtures is close to that of the smaller component. For low viscosity oils, the permeability in coarse sediments is rapid enough to match the fall and rise of tidal water. Effective porosity of the pebbles was ca 90% of the measured porosity, but for both the granules and a 50-50 pebble/granule mixture, the effective porosity was ca 75% of measured porosity. Results of tidal flushing simulation imply that flushing may be rapid but not efficient. The emulsion completely entered the sediment in the case of pebbles only. 2 refs., 6 figs., 3 tabs

Active Distribute Temperature Sensing to Estimate Vertical Water Content Variations in a Loamy-Sandy Soil

Science.gov (United States)

Ciocca, F.; Van De Giesen, N.; Assouline, S.; Huwald, H.; Hopmans, J. W.; Lunati, I.; Parlange, M. B.

2011-12-01

Optical fibers in combination with Raman scattering measurements (Distributed Temperature Sensor: DTS) have recently become more standard for the measurement of soil temperature. A recently developed technique to measure soil moisture called Active DTS (ADTS) is investigated in this study. ADTS consists of an application of a heat pulse for a fixed duration and power along the metal sheath covering the optical fiber placed in the soil. Soil moisture can be inferred from the increased temperature measured during the heating phase and the subsequent temperature decrease during the cooling phase. We assess this technique for a loamy-sandy soil as part of a field campaign that took place during the 2011 summer at EPFL. The measurements were taken within a weighing lysimeter (2.5 m depth and 1.2 m diameter) using an optical fiber arranged in 15 loops for a total measurement length of 52 m in the top 80 cm of the soil profile. Local soil moistures were simultaneously measured using capacity-based probes. Thermocouples, wrapped around the fiber, are used to account for the effects of the insulating cover surrounding the cable. Heat pulses of various duration and power have been applied for a range of soil moistures. Measurements were taken during periods of drainage and evaporation. The accuracy of the technique for the EPFL 2011 field campaign and the experiment are discussed and the soil moisture measurements are presented.

Faunistic assemblages of a sublittoral coarse sand habitat of the northwestern Mediterranean

Directory of Open Access Journals (Sweden)

Eva Pubill

2011-02-01

Full Text Available The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1 assemblage MSS (Medium Sand Shallow in medium sand (D50=0.37 mm and shallow waters (mean depth =6.5 m, (2 assemblage CSS (Coarse Sand Shallow in coarse sand (D50=0.62 mm in shallow waters (mean depth =6.7 m, and (3 assemblage CSD (Coarse Sand Deep in coarse sand (D50=0.64 mm in deeper waters (mean depth =16.2 m. Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community.

Coarse graining flow of spin foam intertwiners

Science.gov (United States)

Dittrich, Bianca; Schnetter, Erik; Seth, Cameron J.; Steinhaus, Sebastian

2016-12-01

Simplicity constraints play a crucial role in the construction of spin foam models, yet their effective behavior on larger scales is scarcely explored. In this article we introduce intertwiner and spin net models for the quantum group SU (2 )k×SU (2 )k, which implement the simplicity constraints analogous to four-dimensional Euclidean spin foam models, namely the Barrett-Crane (BC) and the Engle-Pereira-Rovelli-Livine/Freidel-Krasnov (EPRL/FK) model. These models are numerically coarse grained via tensor network renormalization, allowing us to trace the flow of simplicity constraints to larger scales. In order to perform these simulations we have substantially adapted tensor network algorithms, which we discuss in detail as they can be of use in other contexts. The BC and the EPRL/FK model behave very differently under coarse graining: While the unique BC intertwiner model is a fixed point and therefore constitutes a two-dimensional topological phase, BC spin net models flow away from the initial simplicity constraints and converge to several different topological phases. Most of these phases correspond to decoupling spin foam vertices; however we find also a new phase in which this is not the case, and in which a nontrivial version of the simplicity constraints holds. The coarse graining flow of the BC spin net models indicates furthermore that the transitions between these phases are not of second order. The EPRL/FK model by contrast reveals a far more intricate and complex dynamics. We observe an immediate flow away from the original simplicity constraints; however, with the truncation employed here, the models generically do not converge to a fixed point. The results show that the imposition of simplicity constraints can indeed lead to interesting and also very complex dynamics. Thus we need to further develop coarse graining tools to efficiently study the large scale behavior of spin foam models, in particular for the EPRL/FK model.

Coarse graining from variationally enhanced sampling applied to the Ginzburg-Landau model

Science.gov (United States)

Invernizzi, Michele; Valsson, Omar; Parrinello, Michele

2017-03-01

A powerful way to deal with a complex system is to build a coarse-grained model capable of catching its main physical features, while being computationally affordable. Inevitably, such coarse-grained models introduce a set of phenomenological parameters, which are often not easily deducible from the underlying atomistic system. We present a unique approach to the calculation of these parameters, based on the recently introduced variationally enhanced sampling method. It allows us to obtain the parameters from atomistic simulations, providing thus a direct connection between the microscopic and the mesoscopic scale. The coarse-grained model we consider is that of Ginzburg-Landau, valid around a second-order critical point. In particular, we use it to describe a Lennard-Jones fluid in the region close to the liquid-vapor critical point. The procedure is general and can be adapted to other coarse-grained models.

Learning to Play Efficient Coarse Correlated Equilibria

KAUST Repository

Borowski, Holly P.; Marden, Jason R.; Shamma, Jeff S.

2018-01-01

The majority of the distributed learning literature focuses on convergence to Nash equilibria. Coarse correlated equilibria, on the other hand, can often characterize more efficient collective behavior than even the best Nash equilibrium. However

The combustion of sound and rotten coarse woody debris: a review

Science.gov (United States)

Joshua C. Hyde; Alistair M.S. Smith; Roger D. Ottmar; Ernesto C. Alvarado; Penelope Morgan

2011-01-01

Coarse woody debris serves many functions in forest ecosystem processes and has important implications for fire management as it affects air quality, soil heating and carbon budgets when it combusts. There is relatively little research evaluating the physical properties relating to the combustion of this coarse woody debris with even less specifically addressing...

Fine root dynamics for forests on contrasting soils in the Colombian Amazon

Directory of Open Access Journals (Sweden)

E. M. Jiménez

2009-12-01

Full Text Available It has been hypothesized that as soil fertility increases, the amount of carbon allocated to below-ground production (fine roots should decrease. To evaluate this hypothesis, we measured the standing crop fine root mass and the production of fine roots (<2 mm by two methods: (1 ingrowth cores and, (2 sequential soil coring, during 2.2 years in two lowland forests growing on different soils types in the Colombian Amazon. Differences of soil resources were defined by the type and physical and chemical properties of soil: a forest on clay loam soil (Endostagnic Plinthosol at the Amacayacu National Natural Park and, the other on white sand (Ortseinc Podzol at the Zafire Biological Station, located in the Forest Reservation of the Calderón River. We found that the standing crop fine root mass and the production was significantly different between soil depths (0–10 and 10–20 cm and also between forests. The loamy sand forest allocated more carbon to fine roots than the clay loam forest with the production in loamy sand forest twice (mean±standard error=2.98±0.36 and 3.33±0.69 Mg C ha⁻¹ yr⁻¹, method 1 and 2, respectively as much as for the more fertile loamy soil forest (1.51±0.14, method 1, and from 1.03±0.31 to 1.36±0.23 Mg C ha⁻¹ yr⁻¹, method 2. Similarly, the average of standing crop fine root mass was higher in the white-sands forest (10.94±0.33 Mg C ha⁻¹ as compared to the forest on the more fertile soil (from 3.04±0.15 to 3.64±0.18 Mg C ha⁻¹. The standing crop fine root mass also showed a temporal pattern related to rainfall, with the production of fine roots decreasing substantially in the dry period of the year 2005. These results suggest that soil resources may play an important role in patterns of carbon allocation to the production of fine roots in these forests as the proportion of carbon allocated to above- and below-ground organs is different

Use of selected waste materials in concrete mixes

International Nuclear Information System (INIS)

Batayneh, Malek; Marie, Iqbal; Asi, Ibrahim

2007-01-01

A modern lifestyle, alongside the advancement of technology has led to an increase in the amount and type of waste being generated, leading to a waste disposal crisis. This study tackles the problem of the waste that is generated from construction fields, such as demolished concrete, glass, and plastic. In order to dispose of or at least reduce the accumulation of certain kinds of waste, it has been suggested to reuse some of these waste materials to substitute a percentage of the primary materials used in the ordinary portland cement concrete (OPC). The waste materials considered to be recycled in this study consist of glass, plastics, and demolished concrete. Such recycling not only helps conserve natural resources, but also helps solve a growing waste disposal crisis. Ground plastics and glass were used to replace up to 20% of fine aggregates in concrete mixes, while crushed concrete was used to replace up to 20% of coarse aggregates. To evaluate these replacements on the properties of the OPC mixes, a number of laboratory tests were carried out. These tests included workability, unit weight, compressive strength, flexural strength, and indirect tensile strength (splitting). The main findings of this investigation revealed that the three types of waste materials could be reused successfully as partial substitutes for sand or coarse aggregates in concrete mixtures

Use of selected waste materials in concrete mixes.

Science.gov (United States)

Batayneh, Malek; Marie, Iqbal; Asi, Ibrahim

2007-01-01

A modern lifestyle, alongside the advancement of technology has led to an increase in the amount and type of waste being generated, leading to a waste disposal crisis. This study tackles the problem of the waste that is generated from construction fields, such as demolished concrete, glass, and plastic. In order to dispose of or at least reduce the accumulation of certain kinds of waste, it has been suggested to reuse some of these waste materials to substitute a percentage of the primary materials used in the ordinary portland cement concrete (OPC). The waste materials considered to be recycled in this study consist of glass, plastics, and demolished concrete. Such recycling not only helps conserve natural resources, but also helps solve a growing waste disposal crisis. Ground plastics and glass were used to replace up to 20% of fine aggregates in concrete mixes, while crushed concrete was used to replace up to 20% of coarse aggregates. To evaluate these replacements on the properties of the OPC mixes, a number of laboratory tests were carried out. These tests included workability, unit weight, compressive strength, flexural strength, and indirect tensile strength (splitting). The main findings of this investigation revealed that the three types of waste materials could be reused successfully as partial substitutes for sand or coarse aggregates in concrete mixtures.

NEW RSW & Wall Coarse Tet Only Grid

Data.gov (United States)

National Aeronautics and Space Administration — This is the RSW Coarse Tet Only grid with the root viscous tunnel wall. This grid is for a node-based unstructured solver. Quad Surface Faces= 0 Tria Surface Faces=...

Mutually unbiased coarse-grained measurements of two or more phase-space variables

Science.gov (United States)

Paul, E. C.; Walborn, S. P.; Tasca, D. S.; Rudnicki, Łukasz

2018-05-01

Mutual unbiasedness of the eigenstates of phase-space operators—such as position and momentum, or their standard coarse-grained versions—exists only in the limiting case of infinite squeezing. In Phys. Rev. Lett. 120, 040403 (2018), 10.1103/PhysRevLett.120.040403, it was shown that mutual unbiasedness can be recovered for periodic coarse graining of these two operators. Here we investigate mutual unbiasedness of coarse-grained measurements for more than two phase-space variables. We show that mutual unbiasedness can be recovered between periodic coarse graining of any two nonparallel phase-space operators. We illustrate these results through optics experiments, using the fractional Fourier transform to prepare and measure mutually unbiased phase-space variables. The differences between two and three mutually unbiased measurements is discussed. Our results contribute to bridging the gap between continuous and discrete quantum mechanics, and they could be useful in quantum-information protocols.

Coarse graining from variationally enhanced sampling applied to the Ginzburg–Landau model

Science.gov (United States)

Invernizzi, Michele; Valsson, Omar; Parrinello, Michele

2017-01-01

A powerful way to deal with a complex system is to build a coarse-grained model capable of catching its main physical features, while being computationally affordable. Inevitably, such coarse-grained models introduce a set of phenomenological parameters, which are often not easily deducible from the underlying atomistic system. We present a unique approach to the calculation of these parameters, based on the recently introduced variationally enhanced sampling method. It allows us to obtain the parameters from atomistic simulations, providing thus a direct connection between the microscopic and the mesoscopic scale. The coarse-grained model we consider is that of Ginzburg–Landau, valid around a second-order critical point. In particular, we use it to describe a Lennard–Jones fluid in the region close to the liquid–vapor critical point. The procedure is general and can be adapted to other coarse-grained models. PMID:28292890

A Coarse-Grained Molecular Dynamics Study of DLPC, DMPC, DPPC, and DSPC Mixtures in Aqueous Solution

Directory of Open Access Journals (Sweden)

Roghayeh Abedi Karjiban

2013-01-01

Full Text Available The structural and dynamics properties of the bilayer comprising 128 molecules of dipalmitoylphosphatidylcholine (DPPC, dilauroylphosphatidylcholine (DLPC, dimyristoylphosphatidylcholine (DMPC, and distearoylphosphatidylcholine (DSPC in water were investigated using a coarse-grained molecular dynamics (CG-MD simulation technique. The model mixture system was simulated at 298 K under semi-isotropic pressure conditions. The aggregation was initiated from the random configurations followed by the formation of a bilayer over a period of 500 ns. The calculated values of the area per lipid, thickness, and lateral diffusion for the mixed model were different from when a single lipid was used. Our results confirmed that the chain length of the lipid molecules strongly affects the phospholipid bilayer’s physical properties.

Estimating the shear strength of concrete with coarse aggregate replacement

OpenAIRE

Folagbade Olusoga Peter ORIOLA; George MOSES; Jacob Oyeniyi AFOLAYAN; John Engbonye SANI

2017-01-01

For economic, environmental and practical reasons, it is desirable to replace the constituents of concrete with wastes and cheaper alternative materials. However, it is best when such replacements are done at optimum replacement levels. In view of this, a laboratory investigative test was carried out to evaluate the shear strength of concrete with coarse aggregate replacement by Coconut Shell and by Waste Rubber Tyre. The coarse aggregate replacement was done at recommended optimum proportion...

Coarse-to-fine region selection and matching

KAUST Repository

Yang, Yanchao

2015-10-15

We present a new approach to wide baseline matching. We propose to use a hierarchical decomposition of the image domain and coarse-to-fine selection of regions to match. In contrast to interest point matching methods, which sample salient regions to reduce the cost of comparing all regions in two images, our method eliminates regions systematically to achieve efficiency. One advantage of our approach is that it is not restricted to covariant salient regions, which is too restrictive under large viewpoint and leads to few corresponding regions. Affine invariant matching of regions in the hierarchy is achieved efficiently by a coarse-to-fine search of the affine space. Experiments on two benchmark datasets shows that our method finds more correct correspondence of the image (with fewer false alarms) than other wide baseline methods on large viewpoint change. © 2015 IEEE.

Calibration and validation of coarse-grained models of atomic systems: application to semiconductor manufacturing

Science.gov (United States)

Farrell, Kathryn; Oden, J. Tinsley

2014-07-01

Coarse-grained models of atomic systems, created by aggregating groups of atoms into molecules to reduce the number of degrees of freedom, have been used for decades in important scientific and technological applications. In recent years, interest in developing a more rigorous theory for coarse graining and in assessing the predictivity of coarse-grained models has arisen. In this work, Bayesian methods for the calibration and validation of coarse-grained models of atomistic systems in thermodynamic equilibrium are developed. For specificity, only configurational models of systems in canonical ensembles are considered. Among major challenges in validating coarse-grained models are (1) the development of validation processes that lead to information essential in establishing confidence in the model's ability predict key quantities of interest and (2), above all, the determination of the coarse-grained model itself; that is, the characterization of the molecular architecture, the choice of interaction potentials and thus parameters, which best fit available data. The all-atom model is treated as the "ground truth," and it provides the basis with respect to which properties of the coarse-grained model are compared. This base all-atom model is characterized by an appropriate statistical mechanics framework in this work by canonical ensembles involving only configurational energies. The all-atom model thus supplies data for Bayesian calibration and validation methods for the molecular model. To address the first challenge, we develop priors based on the maximum entropy principle and likelihood functions based on Gaussian approximations of the uncertainties in the parameter-to-observation error. To address challenge (2), we introduce the notion of model plausibilities as a means for model selection. This methodology provides a powerful approach toward constructing coarse-grained models which are most plausible for given all-atom data. We demonstrate the theory and

Bayesian calibration of coarse-grained forces: Efficiently addressing transferability

International Nuclear Information System (INIS)

Patrone, Paul N.; Rosch, Thomas W.; Phelan, Frederick R.

2016-01-01

Generating and calibrating forces that are transferable across a range of state-points remains a challenging task in coarse-grained (CG) molecular dynamics. In this work, we present a coarse-graining workflow, inspired by ideas from uncertainty quantification and numerical analysis, to address this problem. The key idea behind our approach is to introduce a Bayesian correction algorithm that uses functional derivatives of CG simulations to rapidly and inexpensively recalibrate initial estimates f 0 of forces anchored by standard methods such as force-matching. Taking density-temperature relationships as a running example, we demonstrate that this algorithm, in concert with various interpolation schemes, can be used to efficiently compute physically reasonable force curves on a fine grid of state-points. Importantly, we show that our workflow is robust to several choices available to the modeler, including the interpolation schemes and tools used to construct f 0 . In a related vein, we also demonstrate that our approach can speed up coarse-graining by reducing the number of atomistic simulations needed as inputs to standard methods for generating CG forces.

Bayesian calibration of coarse-grained forces: Efficiently addressing transferability

Science.gov (United States)

Patrone, Paul N.; Rosch, Thomas W.; Phelan, Frederick R.

2016-04-01

Generating and calibrating forces that are transferable across a range of state-points remains a challenging task in coarse-grained (CG) molecular dynamics. In this work, we present a coarse-graining workflow, inspired by ideas from uncertainty quantification and numerical analysis, to address this problem. The key idea behind our approach is to introduce a Bayesian correction algorithm that uses functional derivatives of CG simulations to rapidly and inexpensively recalibrate initial estimates f0 of forces anchored by standard methods such as force-matching. Taking density-temperature relationships as a running example, we demonstrate that this algorithm, in concert with various interpolation schemes, can be used to efficiently compute physically reasonable force curves on a fine grid of state-points. Importantly, we show that our workflow is robust to several choices available to the modeler, including the interpolation schemes and tools used to construct f0. In a related vein, we also demonstrate that our approach can speed up coarse-graining by reducing the number of atomistic simulations needed as inputs to standard methods for generating CG forces.

Evaluation of Diuron Tolerance and Biotransformation by Fungi from a Sugar Cane Plantation Sandy-Loam Soil.

Science.gov (United States)

Perissini-Lopes, Bruna; Egea, Tássia Chiachio; Monteiro, Diego Alves; Vici, Ana Cláudia; Da Silva, Danilo Grünig Humberto; Lisboa, Daniela Correa de Oliveira; de Almeida, Eduardo Alves; Parsons, John Robert; Da Silva, Roberto; Gomes, Eleni

2016-12-14

Microorganisms capable of degrading herbicides are essential to minimize the amount of chemical compounds that may leach into other environments. This work aimed to study the potential of sandy-loam soil fungi to tolerate the herbicide Herburon (50% diuron) and to degrade the active ingredient diuron. Verticillium sp. F04, Trichoderma virens F28, and Cunninghamella elegans B06 showed the highest growth in the presence of the herbicide. The evaluation of biotransformation showed that Aspergillus brasiliensis G08, Aspergillus sp. G25, and Cunninghamella elegans B06 had the greatest potential to degrade diuron. Statistical analysis demonstrated that glucose positively influences the potential of the microorganism to degrade diuron, indicating a cometabolic process. Due to metabolites founded by diuron biotransformation, it is indicated that the fungi are relevant in reducing the herbicide concentration in runoff, minimizing the environmental impact on surrounding ecosystems.

Direct and Indirect Short-term Effects of Biochar on Physical Characteristics of an Arable Sandy Loam

DEFF Research Database (Denmark)

Sun, Zhencai; Moldrup, Per; Elsgaard, Lars

2013-01-01

Biochar addition to agricultural soil is reported in several studies to reduce climate gas emissions, boost carbon storage, and improve soil fertility and crop productivity. These effects may be partly related to soil physical changes resulting from biochar amendment, but knowledge of how biochar...... application mechanistically affects soil physical characteristics is limited. This study investigated the effect of biochar application on soil structural and functional properties, including specific surface area, water retention, and gas transport parameters. Intact soil cores were taken from a field...... experiment on an arable sandy loam that included four reference plots without biochar and four plots with 20 tons ha(-1) biochar incorporated into the upper 20 cm 7 months before sampling. Water retention was measured at matric potentials ranging from wet (pF 1.0) to extremely dry conditions (pF similar to 6...

Effect of biochar on aerobic processes, enzyme activity, and crop yields in two sandy loam soils

DEFF Research Database (Denmark)

Sun, Zhencai; Bruun, Esben; Arthur, Emmanuel

2014-01-01

Biochar added to agricultural soils may sequester carbon and improve physico-chemical conditions for crop growth, due to effects such as increased water and nutrient retention in the root zone. The effects of biochar on soil microbiological properties are less certain. We addressed the effects...... of wood-based biochar on soil respiration, water contents, potential ammonia oxidation (PAO), arylsulfatase activity (ASA), and crop yields at two temperate sandy loam soils under realistic field conditions. In situ soil respiration, PAO, and ASA were not significantly different in quadruplicate field...... plots with or without biochar (20 Mg ha−1); however, in the same plots, volumetric water contents increased by 7.5 % due to biochar (P = 0.007). Crop yields (oat) were not significantly different in the first year after biochar application, but in the second year, total yields of spring barley increased...

Coarse and fine sediment transportation patterns and causes downstream of the Three Gorges Dam

Science.gov (United States)

Li, Songzhe; Yang, Yunping; Zhang, Mingjin; Sun, Zhaohua; Zhu, Lingling; You, Xingying; Li, Kanyu

2017-11-01

Reservoir construction within a basin affects the process of water and sediment transport downstream of the dam. The Three Gorges Reservoir (TGR) affects the sediment transport downstream of the dam. The impoundment of the TGR reduced total downstream sediment. The sediment group d≤0.125 mm (fine particle) increased along the path, but the average was still below what existed before the reservoir impoundment. The sediments group d>0.125 mm (coarse particle) was recharged in the Yichang to Jianli reach, but showed a deposition trend downstream of Jianli. The coarse sediment in the Yichang to Jianli section in 2003 to 2007 was above the value before the TGR impoundment. However, the increase of both coarse and fine sediments in 2008 to 2014 was less than that in 2003 to 2007. The sediment retained in the dam is the major reason for the sediment reduction downstream. However, the retention in different river reaches is affected by riverbed coarsening, discharge, flow process, and conditions of lake functioning and recharging from the tributaries. The main conclusions derived from our study are as follows: 1) The riverbed in the Yichang to Shashi section was relatively coarse, thereby limiting the supply of fine and coarse sediments. The fine sediment supply was mainly controlled by TGR discharge, whereas the coarse sediment supply was controlled by the duration of high flow and its magnitude. 2) The supply of both coarse and fine sediments in the Shashi to Jianli section was controlled by the amount of total discharge. The sediment supply from the riverbed was higher in flood years than that in the dry years. The coarse sediment tended to deposit, and the deposition in the dry years was larger than that in the flood years. 3) The feeding of the fine sediment in the Luoshan to Hankou section was mainly from the riverbed. The supply in 2008 to 2014 was more than that in 2003 to 2007. Around 2010, the coarse sediments transited from depositing to scouring that was

Combining fine texture and coarse color features for color texture classification

Science.gov (United States)

Wang, Junmin; Fan, Yangyu; Li, Ning

2017-11-01

Color texture classification plays an important role in computer vision applications because texture and color are two fundamental visual features. To classify the color texture via extracting discriminative color texture features in real time, we present an approach of combining the fine texture and coarse color features for color texture classification. First, the input image is transformed from RGB to HSV color space to separate texture and color information. Second, the scale-selective completed local binary count (CLBC) algorithm is introduced to extract the fine texture feature from the V component in HSV color space. Third, both H and S components are quantized at an optimal coarse level. Furthermore, the joint histogram of H and S components is calculated, which is considered as the coarse color feature. Finally, the fine texture and coarse color features are combined as the final descriptor and the nearest subspace classifier is used for classification. Experimental results on CUReT, KTH-TIPS, and New-BarkTex databases demonstrate that the proposed method achieves state-of-the-art classification performance. Moreover, the proposed method is fast enough for real-time applications.

Terrain aided navigation for autonomous underwater vehicles with coarse maps

International Nuclear Information System (INIS)

Zhou, Ling; Cheng, Xianghong; Zhu, Yixian

2016-01-01

Terrain aided navigation (TAN) is a form of geophysical localization technique for autonomous underwater vehicles (AUVs) operating in GPS-denied environments. TAN performance on sensor-rich AUVs has been evaluated in sea trials. However, many challenges remain before TAN can be successfully implemented on sensor-limited AUVs, especially with coarse maps. To improve TAN performance over coarse maps, a Gaussian process (GP) is proposed for the modeling of bathymetric terrain and integrated into the particle filter (GP-PF). GP is applied to provide not only the bathymetric value prediction through learning a set of bathymetric data from coarse maps but also the variance of the prediction. As a measurement update, calculated on bathymetric deviation is performed through the PF to obtain absolute and bounded positioning accuracy. Through the analysis of TAN performance on experimental data for two different terrains with map resolutions of 10–50 m, both the ability of the proposed model to represent the actual bathymetric terrain with accuracy and the effect of the GP-PF for TAN on sensor-limited systems in suited terrain are demonstrated. The experiment results further verify that there is an inverse relationship between the coarseness of the map and the overall TAN accuracy in rough terrains, but there is hardly any relationship between them in relatively flat terrains. (paper)

Fundamental Study on the Development of Structural Lightweight Concrete by Using Normal Coarse Aggregate and Foaming Agent

Science.gov (United States)

Lee, Han-Seung; Ismail, Mohamed A.; Woo, Young-Je; Min, Tae-Beom; Choi, Hyun-Kook

2014-01-01

Structural lightweight concrete (SLWC) has superior properties that allow the optimization of super tall structure systems for the process of design. Because of the limited supply of lightweight aggregates in Korea, the development of structural lightweight concrete without lightweight aggregates is needed. The physical and mechanical properties of specimens that were cast using normal coarse aggregates and different mixing ratios of foaming agent to evaluate the possibility of creating structural lightweight concrete were investigated. The results show that the density of SLWC decreases as the dosage of foaming agent increases up to a dosage of 0.6%, as observed by SEM. It was also observed that the foaming agent induced well separated pores, and that the size of the pores ranged from 50 to 100 μm. Based on the porosity of concrete specimens with foaming agent, compressive strength values of structural lightweight foam concrete (SLWFC) were obtained. It was also found that the estimated values from proposed equations for compressive strength and modulus of elasticity of SLWFC, and values obtained by actual measurements were in good agreement. Thus, this study confirms that new structural lightweight concrete using normal coarse aggregates and foaming agent can be developed successfully. PMID:28788691

Systematic and simulation-free coarse graining of homopolymer melts: A structure-based study

International Nuclear Information System (INIS)

Yang, Delian; Wang, Qiang

2015-01-01

We propose a systematic and simulation-free strategy for coarse graining of homopolymer melts, where each chain of N m monomers is uniformly divided into N segments, with the spatial position of each segment corresponding to the center-of-mass of its monomers. We use integral-equation theories suitable for the study of equilibrium properties of polymers, instead of many-chain molecular simulations, to obtain the structural and thermodynamic properties of both original and coarse-grained (CG) systems, and quantitatively examine how the effective pair potentials between CG segments and the thermodynamic properties of CG systems vary with N. Our systematic and simulation-free strategy is much faster than those using many-chain simulations, thus effectively solving the transferability problem in coarse graining, and provides the quantitative basis for choosing the appropriate N-values. It also avoids the problems caused by finite-size effects and statistical uncertainties in many-chain simulations. Taking the simple hard-core Gaussian thread model [K. S. Schweizer and J. G. Curro, Chem. Phys. 149, 105 (1990)] as the original system, we demonstrate our strategy applied to structure-based coarse graining, which is quite general and versatile, and compare in detail the various integral-equation theories and closures for coarse graining. Our numerical results show that the effective CG potentials for various N and closures can be collapsed approximately onto the same curve, and that structure-based coarse graining cannot give thermodynamic consistency between original and CG systems at any N < N m

MT-ADRES: Multithreading on Coarse-Grained Reconfigurable Architecture

DEFF Research Database (Denmark)

Wu, Kehuai; Kanstein, Andreas; Madsen, Jan

2007-01-01

The coarse-grained reconfigurable architecture ADRES (Architecture for Dynamically Reconfigurable Embedded Systems) and its compiler offer high instruction-level parallelism (ILP) to applications by means of a sparsely interconnected array of functional units and register files. As high-ILP archi......The coarse-grained reconfigurable architecture ADRES (Architecture for Dynamically Reconfigurable Embedded Systems) and its compiler offer high instruction-level parallelism (ILP) to applications by means of a sparsely interconnected array of functional units and register files. As high......-ILP architectures achieve only low parallelism when executing partially sequential code segments, which is also known as Amdahl’s law, this paper proposes to extend ADRES to MT-ADRES (Multi-Threaded ADRES) to also exploit thread-level parallelism. On MT-ADRES architectures, the array can be partitioned in multiple...

Influence of uncoated and coated plastic waste coarse aggregates to concrete compressive strength

Directory of Open Access Journals (Sweden)

Purnomo Heru

2017-01-01

Full Text Available The use of plastic waste as coarse aggregates in concrete is part of efforts to reduce environmental pollution. In one hand the use of plastic as aggregates can provide lighter weight of the concrete than concrete using natural aggregates, but on the other hand bond between plastic coarse aggregates and hard matrix give low concrete compressive strength. Improvement of the bond between plastic coarse aggregate and hard matrix through a sand coating to plastic coarse aggregate whole surface is studied. Sand used to coat the plastic aggregates are Merapi volcanic sand which are taken in Magelang. Three mixtures of polypropylene (PP coarse plastic aggregates, Cimangkok river sand as fine aggregates, water and Portland Cement Composite with a water-cement ratio of 0.28, 0.3 and 0.35 are conducted. Compression test are performed on concrete cylindrical specimens with a diameter of 10 cm and a height of 20 cm. The results in general show that concrete specimens using plastic aggregates coated with sand have higher compressive strength compared to those of concrete specimens using plastic aggregates without sand coating. The bond improvement is indirectly indicated by the betterment of concrete compressive strength.

Optimal Design of Experiments by Combining Coarse and Fine Measurements

Science.gov (United States)

Lee, Alpha A.; Brenner, Michael P.; Colwell, Lucy J.

2017-11-01

In many contexts, it is extremely costly to perform enough high-quality experimental measurements to accurately parametrize a predictive quantitative model. However, it is often much easier to carry out large numbers of experiments that indicate whether each sample is above or below a given threshold. Can many such categorical or "coarse" measurements be combined with a much smaller number of high-resolution or "fine" measurements to yield accurate models? Here, we demonstrate an intuitive strategy, inspired by statistical physics, wherein the coarse measurements are used to identify the salient features of the data, while the fine measurements determine the relative importance of these features. A linear model is inferred from the fine measurements, augmented by a quadratic term that captures the correlation structure of the coarse data. We illustrate our strategy by considering the problems of predicting the antimalarial potency and aqueous solubility of small organic molecules from their 2D molecular structure.

Coarse Grained Molecular Dynamics Simulations of Transmembrane Protein-Lipid Systems

Directory of Open Access Journals (Sweden)

Peter Spijker

2010-06-01

Full Text Available Many biological cellular processes occur at the micro- or millisecond time scale. With traditional all-atom molecular modeling techniques it is difficult to investigate the dynamics of long time scales or large systems, such as protein aggregation or activation. Coarse graining (CG can be used to reduce the number of degrees of freedom in such a system, and reduce the computational complexity. In this paper the first version of a coarse grained model for transmembrane proteins is presented. This model differs from other coarse grained protein models due to the introduction of a novel angle potential as well as a hydrogen bonding potential. These new potentials are used to stabilize the backbone. The model has been validated by investigating the adaptation of the hydrophobic mismatch induced by the insertion of WALP-peptides into a lipid membrane, showing that the first step in the adaptation is an increase in the membrane thickness, followed by a tilting of the peptide.

Soil nitrogen dynamics and Capsicum Annuum sp. plant response to biochar amendment in silt loam soil

Science.gov (United States)

Horel, Agota; Gelybo, Gyorgyi; Dencso, Marton; Toth, Eszter; Farkas, Csilla; Kasa, Ilona; Pokovai, Klara

2017-04-01

The present study investigated the growth of Capsicum Annuum sp. (pepper) in small-scale experiment to observe changes in plant growth and health as reflected by leaf area, plant height, yield, root density, and nitrogen usage. Based on field conditions, part of the study aimed to examine the photosynthetic and photochemical responses of plants to treatments resulting from different plant growth rates. During the 12.5 week long study, four treatments were investigated with biochar amount of 0, 0.5%, 2.5%, and 5.0% (by weight) added to silt loam soil. The plants were placed under natural environmental conditions, such that photosynthetic activities from photosynthetically active radiation (PAR) and the plants photochemical reflectance index (PRI) could be continuously measured after exposure to sunlight. In this study we found that benefits from biochar addition to silt loam soil most distinguishable occurred in the BC2.5 treatments, where the highest plant yield, highest root density, and highest leaf areas were observed compared to other treatments. Furthermore, data showed that too low (0.5%) or too high (5.0%) biochar addition to the soil had diminishing effects on Capsicum Annuum sp. growth and yield over time. At the end of the 12th week, BC2.5 had 22.2%, while BC0.5 and BC5.0 showed 17.4% and 15.7% increase in yield dry weight respectively compared to controls. The collected data also showed that the PRI values of plants growing on biochar treated soils were generally lower compared to control treatments, which could relate to leaf nitrogen levels. Total nitrogen amount showed marginal changes over time in all treatments. The total nitrogen concentration showed 28.6% and 17.7% increase after the 6th week of the experiment for BC2.5 and BC5.0, respectively, while inorganic nutrients of NO3-N and NH4+-N showed a continuous decrease during the course of the study, with a substantial drop during the first few weeks. The present study provides evidence for impact

Effects of coarse-graining on the scaling behavior of long-range correlated and anti-correlated signals

OpenAIRE

Xu, Yinlin; Ma, Qianli D.Y.; Schmitt, Daniel T.; Bernaola-Galván, Pedro; Ivanov, Plamen Ch.

2011-01-01

We investigate how various coarse-graining methods affect the scaling properties of long-range power-law correlated and anti-correlated signals, quantified by the detrended fluctuation analysis. Specifically, for coarse-graining in the magnitude of a signal, we consider (i) the Floor, (ii) the Symmetry and (iii) the Centro-Symmetry coarse-graining methods. We find, that for anti-correlated signals coarse-graining in the magnitude leads to a crossover to random behavior at large scales, and th...

Electroosmotic Flow in Mixed Polymer Brush-Grafted Nanochannels

Directory of Open Access Journals (Sweden)

Qianqian Cao

2016-12-01

Full Text Available Mixed polymer brush-grafted nanochannels—where two distinct species of polymers are alternately grafted on the inner surface of nanochannels—are an interesting class of nanostructured hybrid materials. By using a coarse-grained molecular dynamics simulation method, we are able to simulate the electrokinetic transport dynamics of the fluid in such nanochannels as well as the conformational behaviors of the mixed polymer brush. We find that (1 the brush adopts vertically-layered and longitudinally-separated structures due to the coupling of electroosmotic flow (EOF and applied electric field; (2 the solvent quality affects the brush conformations and the transport properties of the EOF; (3 the EOF flux non-monotonically depends on the grafting density, although the EOF velocity in the central region of the channel monotonically depends on the grafting density.

Development of new test procedures for measuring fine and coarse aggregates specific gravity.

Science.gov (United States)

2009-09-01

The objective of the research is to develop and evaluate new test methods at determining the specific gravity and absorption of both fine and coarse aggregates. Current methods at determining the specific gravity and absorption of fine and coarse agg...

Coarse-grain modelling of protein-protein interactions

NARCIS (Netherlands)

Baaden, Marc; Marrink, Siewert J.

2013-01-01

Here, we review recent advances towards the modelling of protein-protein interactions (PPI) at the coarse-grained (CG) level, a technique that is now widely used to understand protein affinity, aggregation and self-assembly behaviour. PPI models of soluble proteins and membrane proteins are

Genesis and classification of soils developed on gabbro in the high reliefs of Maroua region, North Cameroon

Directory of Open Access Journals (Sweden)

Désiré Tsozué

2017-04-01

Full Text Available The purpose of this work was to examine the genesis, properties and classification of soils resulting from the weathering of gabbro rock in the high reliefs of Maroua in the Far North Region of Cameroon. The studied soils were ~ 2 m thick, made of four horizons which consisted of coarse saprolite, fine saprolite, loose loamy clayey horizon and humiferous horizon. From petrographical view point, at the bottom of the soil profile, the preservation of the bedrock structure was marked by numerous remnants of altered plagioclases shapes. The groundmass was characterized by a double spaced fine, ranging to equal, enaulic c/f related distribution pattern. It was yellowish, characterized by weakly separated granular microstructure in the fine saprolite and had a speckled and cloudy limpidity in the loose loamy clayey horizon. Secondary minerals consisted of montmorilonite, kaolinite, goethite, quartz, gibbsite, lepidocrocite, sepiolite, feldspar and calcite. Globally, Si/Al ratio ranged between 2.85 and 3.24. The chemical index of alteration ranged from 50.95 to 55.27 % while the mineralogical index of alteration values were between 1.90 and 10.54 %. Physicochemically, soil pH varied from slightly acidic to slightly above neutral. Soil organic carbon contents were low to very low. Exchangeable bases contents were high, mostly represented by Ca2+ and Mg2+. The CEC of soils and the CEC of clay were also high, ranging respectively between 53.68 and 82.88 cmol(+.kg-1, and 116.80 and 181.38 cmol(+.kg-1. The studied soils were classified as dystric haplustepts clayey isohyperthermic. They were developed in situ by the collapse of primary mineral structures from the bottom of the coarse saprolite, due to leaching as a result of bisiallitisation and monosiallitisation. This is accompanied by a progressive ferruginization of materials, confirmed by the densification under the microscope of goethitic brown veil from the base to the loamy clay horizon and the

Significance of Fines in Hot Mix Asphalt Synthesis

Directory of Open Access Journals (Sweden)

Kalaitzaki Elvira

2017-07-01

Full Text Available According to their size, aggregates are classified in coarse grained, fine grained, and fines. The determination of fines content in aggregate materials is very simple and is performed through the aggregate washing during the sieving procedure to define the gradation curve. The very fine material consists of grains having a size lower than 63 μm. The presence of fines directly influences the composition and performance of concrete and asphalt mixtures (e.g. asphalt content, elasticity, fracture. The strength and load carrying capacity of hot mix asphalt (HMA results from the aggregate framework created through particle-particle contact and interlock. Fines or mineral filler have a role in HMA. The coarse aggregate framework is filled by the sand-sized material and finally by the mineral filler. At some point, the smallest particles lose contact becoming suspended in the binder not having the particle-particle contact that is created by the larger particles. The overall effect of mineral filler in hot mix asphalt specimens has been investigated through a series of laboratory tests. It is clear that a behaviour influenced by the adherence of fines to asphalt film has been developed. The optimum bitumen content requirement in case of stone filler is almost the same as that for fly ash. It has been found that the percentage of fly ash filler is crucial if it exceeds approximately a value of 4%.

Parametrizing coarse grained models for molecular systems at equilibrium

KAUST Repository

Kalligiannaki, Evangelia; Chazirakis, A.; Tsourtis, A.; Katsoulakis, M. A.; Plechá č, P.; Harmandaris, V.

2016-01-01

Hierarchical coarse graining of atomistic molecular systems at equilibrium has been an intensive research topic over the last few decades. In this work we (a) review theoretical and numerical aspects of different parametrization methods (structural-based, force matching and relative entropy) to derive the effective interaction potential between coarse-grained particles. All methods approximate the many body potential of mean force; resulting, however, in different optimization problems. (b) We also use a reformulation of the force matching method by introducing a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (E. Kalligiannaki, et al., J. Chem. Phys. 2015). We apply and compare these methods to: (a) a benchmark system of two isolated methane molecules; (b) methane liquid; (c) water; and (d) an alkane fluid. Differences between the effective interactions, derived from the various methods, are found that depend on the actual system under study. The results further reveal the relation of the various methods and the sensitivities that may arise in the implementation of numerical methods used in each case.

Parametrizing coarse grained models for molecular systems at equilibrium

KAUST Repository

Kalligiannaki, Evangelia

2016-10-18

Hierarchical coarse graining of atomistic molecular systems at equilibrium has been an intensive research topic over the last few decades. In this work we (a) review theoretical and numerical aspects of different parametrization methods (structural-based, force matching and relative entropy) to derive the effective interaction potential between coarse-grained particles. All methods approximate the many body potential of mean force; resulting, however, in different optimization problems. (b) We also use a reformulation of the force matching method by introducing a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (E. Kalligiannaki, et al., J. Chem. Phys. 2015). We apply and compare these methods to: (a) a benchmark system of two isolated methane molecules; (b) methane liquid; (c) water; and (d) an alkane fluid. Differences between the effective interactions, derived from the various methods, are found that depend on the actual system under study. The results further reveal the relation of the various methods and the sensitivities that may arise in the implementation of numerical methods used in each case.

Development of an extraction method for perchlorate in soils.

Science.gov (United States)

Cañas, Jaclyn E; Patel, Rashila; Tian, Kang; Anderson, Todd A

2006-03-01

Perchlorate originates as a contaminant in the environment from its use in solid rocket fuels and munitions. The current US EPA methods for perchlorate determination via ion chromatography using conductivity detection do not include recommendations for the extraction of perchlorate from soil. This study evaluated and identified appropriate conditions for the extraction of perchlorate from clay loam, loamy sand, and sandy soils. Based on the results of this evaluation, soils should be extracted in a dry, ground (mortar and pestle) state with Milli-Q water in a 1 ratio 1 soil ratio water ratio and diluted no more than 5-fold before analysis. When sandy soils were extracted in this manner, the calculated method detection limit was 3.5 microg kg(-1). The findings of this study have aided in the establishment of a standardized extraction method for perchlorate in soil.

The measurement of mixture homogeneity and dissolution to predict the degree of drug agglomerate breakdown achieved through powder mixing.

Science.gov (United States)

de Villiers, M M; Van der Watt, J G

1994-11-01

Interactive mixing of agglomerates of small, cohesive particles with coarse carrier particles facilitate the deaggregation of agglomerates. In this study dispersion of agglomerates of microfine furosemide particles by such a mixing process was followed by measuring changes in the content uniformity and area under the dissolution curve. Interactive mixtures between agglomerates of different sized furosemide particles and coarse sodium chloride particles were prepared using different mixers, mixing times and mixer speeds. The dissolution rate of the drug from and content uniformity of the mixtures were measured, and degrees of dispersion were calculated. These degrees of dispersion were compared to the dispersion values obtained from the decrease in agglomerate size after mixing. An increase in mixing time led to an increase in dispersion. An initial fast deagglomeration, indicated by an increase in dissolution, increase in content uniformity and a decrease in particle size, was followed by substantially slower deaggregation of remaining agglomerates and smaller aggregates. For all mixtures studied the degree of dispersion estimated from dissolution measurements, when compared to equivalent content uniformity measurements, agreed closely with the degree of dispersion as indicated by the decrease in particle size. The use of the area under the dissolution curve to predict agglomerate breakdown proved useful and may find application in situations where it is impossible to follow directly deagglomeration through particle size measurements.

Reactor calculation in coarse mesh by finite element method applied to matrix response method

International Nuclear Information System (INIS)

Nakata, H.

1982-01-01

The finite element method is applied to the solution of the modified formulation of the matrix-response method aiming to do reactor calculations in coarse mesh. Good results are obtained with a short running time. The method is applicable to problems where the heterogeneity is predominant and to problems of evolution in coarse meshes where the burnup is variable in one same coarse mesh, making the cross section vary spatially with the evolution. (E.G.) [pt

Path-space variational inference for non-equilibrium coarse-grained systems

International Nuclear Information System (INIS)

Harmandaris, Vagelis; Kalligiannaki, Evangelia; Katsoulakis, Markos; Plecháč, Petr

2016-01-01

In this paper we discuss information-theoretic tools for obtaining optimized coarse-grained molecular models for both equilibrium and non-equilibrium molecular simulations. The latter are ubiquitous in physicochemical and biological applications, where they are typically associated with coupling mechanisms, multi-physics and/or boundary conditions. In general the non-equilibrium steady states are not known explicitly as they do not necessarily have a Gibbs structure. The presented approach can compare microscopic behavior of molecular systems to parametric and non-parametric coarse-grained models using the relative entropy between distributions on the path space and setting up a corresponding path-space variational inference problem. The methods can become entirely data-driven when the microscopic dynamics are replaced with corresponding correlated data in the form of time series. Furthermore, we present connections and generalizations of force matching methods in coarse-graining with path-space information methods. We demonstrate the enhanced transferability of information-based parameterizations to different observables, at a specific thermodynamic point, due to information inequalities. We discuss methodological connections between information-based coarse-graining of molecular systems and variational inference methods primarily developed in the machine learning community. However, we note that the work presented here addresses variational inference for correlated time series due to the focus on dynamics. The applicability of the proposed methods is demonstrated on high-dimensional stochastic processes given by overdamped and driven Langevin dynamics of interacting particles.

Path-space variational inference for non-equilibrium coarse-grained systems

Energy Technology Data Exchange (ETDEWEB)

Harmandaris, Vagelis, E-mail: harman@uoc.gr [Department of Mathematics and Applied Mathematics, University of Crete (Greece); Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), IACM/FORTH, GR-71110 Heraklion (Greece); Kalligiannaki, Evangelia, E-mail: ekalligian@tem.uoc.gr [Department of Mathematics and Applied Mathematics, University of Crete (Greece); Katsoulakis, Markos, E-mail: markos@math.umass.edu [Department of Mathematics and Statistics, University of Massachusetts at Amherst (United States); Plecháč, Petr, E-mail: plechac@math.udel.edu [Department of Mathematical Sciences, University of Delaware, Newark, Delaware (United States)

2016-06-01

In this paper we discuss information-theoretic tools for obtaining optimized coarse-grained molecular models for both equilibrium and non-equilibrium molecular simulations. The latter are ubiquitous in physicochemical and biological applications, where they are typically associated with coupling mechanisms, multi-physics and/or boundary conditions. In general the non-equilibrium steady states are not known explicitly as they do not necessarily have a Gibbs structure. The presented approach can compare microscopic behavior of molecular systems to parametric and non-parametric coarse-grained models using the relative entropy between distributions on the path space and setting up a corresponding path-space variational inference problem. The methods can become entirely data-driven when the microscopic dynamics are replaced with corresponding correlated data in the form of time series. Furthermore, we present connections and generalizations of force matching methods in coarse-graining with path-space information methods. We demonstrate the enhanced transferability of information-based parameterizations to different observables, at a specific thermodynamic point, due to information inequalities. We discuss methodological connections between information-based coarse-graining of molecular systems and variational inference methods primarily developed in the machine learning community. However, we note that the work presented here addresses variational inference for correlated time series due to the focus on dynamics. The applicability of the proposed methods is demonstrated on high-dimensional stochastic processes given by overdamped and driven Langevin dynamics of interacting particles.

Comparison of coarse-grained (MARTINI) and atomistic molecular ...

Indian Academy of Sciences (India)

Rajat Desikan

as the root mean square deviation (RMSD) histograms and the inner pore radius profiles from ... ever coarse-grained simulations of membrane-proteins ..... from the MARTINI simulations show greater fluctuations than the all-atom simulations.

Coarse grainings and irreversibility in quantum field theory

International Nuclear Information System (INIS)

Anastopoulos, C.

1997-01-01

In this paper we are interested in studying coarse graining in field theories using the language of quantum open systems. Motivated by the ideas of Hu and Calzetta on correlation histories we employ the Zwanzig projection technique to obtain evolution equations for relevant observables in self-interacting scalar field theories. Our coarse-graining operation consists in concentrating solely on the evolution of the correlation functions of degree less than n, a treatment which corresponds to the familiar truncation of the BBKGY hierarchy at the nth level. We derive the equations governing the evolution of mean-field and two-point functions thus identifying the terms corresponding to dissipation and noise. We discuss possible applications of our formalism, the emergence of classical behavior, and the connection to the decoherent histories framework. copyright 1997 The American Physical Society

Model's sparse representation based on reduced mixed GMsFE basis methods

Energy Technology Data Exchange (ETDEWEB)

Jiang, Lijian, E-mail: ljjiang@hnu.edu.cn [Institute of Mathematics, Hunan University, Changsha 410082 (China); Li, Qiuqi, E-mail: qiuqili@hnu.edu.cn [College of Mathematics and Econometrics, Hunan University, Changsha 410082 (China)

2017-06-01

In this paper, we propose a model's sparse representation based on reduced mixed generalized multiscale finite element (GMsFE) basis methods for elliptic PDEs with random inputs. A typical application for the elliptic PDEs is the flow in heterogeneous random porous media. Mixed generalized multiscale finite element method (GMsFEM) is one of the accurate and efficient approaches to solve the flow problem in a coarse grid and obtain the velocity with local mass conservation. When the inputs of the PDEs are parameterized by the random variables, the GMsFE basis functions usually depend on the random parameters. This leads to a large number degree of freedoms for the mixed GMsFEM and substantially impacts on the computation efficiency. In order to overcome the difficulty, we develop reduced mixed GMsFE basis methods such that the multiscale basis functions are independent of the random parameters and span a low-dimensional space. To this end, a greedy algorithm is used to find a set of optimal samples from a training set scattered in the parameter space. Reduced mixed GMsFE basis functions are constructed based on the optimal samples using two optimal sampling strategies: basis-oriented cross-validation and proper orthogonal decomposition. Although the dimension of the space spanned by the reduced mixed GMsFE basis functions is much smaller than the dimension of the original full order model, the online computation still depends on the number of coarse degree of freedoms. To significantly improve the online computation, we integrate the reduced mixed GMsFE basis methods with sparse tensor approximation and obtain a sparse representation for the model's outputs. The sparse representation is very efficient for evaluating the model's outputs for many instances of parameters. To illustrate the efficacy of the proposed methods, we present a few numerical examples for elliptic PDEs with multiscale and random inputs. In particular, a two-phase flow model in

Horizontal Residual Mean Circulation: Evaluation of Spatial Correlations in Coarse Resolution Ocean Models

Science.gov (United States)

Li, Y.; McDougall, T. J.

2016-02-01

Coarse resolution ocean models lack knowledge of spatial correlations between variables on scales smaller than the grid scale. Some researchers have shown that these spatial correlations play a role in the poleward heat flux. In order to evaluate the poleward transport induced by the spatial correlations at a fixed horizontal position, an equation is obtained to calculate the approximate transport from velocity gradients. The equation involves two terms that can be added to the quasi-Stokes streamfunction (based on temporal correlations) to incorporate the contribution of spatial correlations. Moreover, these new terms do not need to be parameterized and is ready to be evaluated by using model data directly. In this study, data from a high resolution ocean model have been used to estimate the accuracy of this HRM approach for improving the horizontal property fluxes in coarse-resolution ocean models. A coarse grid is formed by sub-sampling and box-car averaging the fine grid scale. The transport calculated on the coarse grid is then compared to the transport on original high resolution grid scale accumulated over a corresponding number of grid boxes. The preliminary results have shown that the estimate on coarse resolution grids roughly match the corresponding transports on high resolution grids.

Coarse grained model for semiquantitative lipid simulations

NARCIS (Netherlands)

Marrink, SJ; de Vries, AH; Mark, AE

2004-01-01

This paper describes the parametrization of a new coarse grained (CG) model for lipid and surfactant systems. Reduction of the number of degrees of freedom together with the use of short range potentials makes it computationally very efficient. Compared to atomistic models a gain of 3-4 orders of

Rizoremediação de pentaclorofenol em um solo argiloso por sphingomonas chlorophenolica ATCC 39723 Pentachlorophenol rhizoremediation in a loamy soil by sphingomonas chlorophenolica ATCC 39723

Directory of Open Access Journals (Sweden)

Rosemeri I. Dams

2007-12-01

Full Text Available O principal objetivo deste trabalho foi estudar a degradação de PCP por Sphingomonas chlorophenolicaem solo argiloso na presença e ausência de trigo. As concentrações de PCP foram determinadas através de Análises de Alta Performance de Cromatografia Líquida. Os efeitos tóxicos de PCP foram estudados através do monitoramento do crescimento das plantas. A biodegradação de PCP por S. chlorophenolica foi acompanhada por testes de bioluminescência de Escherichia coli HB101 pUCD607 e contagens bacterianas no solo e nas raízes. A degradação de PCP ocorreu de forma mais rápida no solo plantado e inoculado quando comparada ao solo sem plantas. Houve um aumento significativo nas populações dos organismos testados nas raízes quando comparadas com as populações presentes no solo. O monitoramento do crescimento da planta mostrou o papel protetor exercido pela S.chlorophenolica contra a toxicidade do PCP.The main objective of this study was study the PCP degradation by Sphingomonas chlorophenolica in a loamy soil in the presence and absence of plants (Winter wheat. Measurements of PCP concentrations were carried out in a laboratory basis using High performance liquid chromatography analysis (HPLC. The toxic effect of PCP on plants was studied through the monitoring of the plant growth. The biodegradation of PCP by S. chlorophenolica in soil was assessed with a bioluminescence assay of Escherichia coli HB101 pUCD607 and bacterial analyses in roots and soil. The planted and inoculated soil showed a faster degradation when compared to the inoculated soil without plants. There was a significative increase in the populations of the organisms tested in the roots when compared to the soil. The monitoring of the plant growth showed a protective role of S. chlorophenolica against the toxicity of PCP in the loamy soil.

Coarse-grained stochastic processes and kinetic Monte Carlo simulators for the diffusion of interacting particles

Science.gov (United States)

Katsoulakis, Markos A.; Vlachos, Dionisios G.

2003-11-01

We derive a hierarchy of successively coarse-grained stochastic processes and associated coarse-grained Monte Carlo (CGMC) algorithms directly from the microscopic processes as approximations in larger length scales for the case of diffusion of interacting particles on a lattice. This hierarchy of models spans length scales between microscopic and mesoscopic, satisfies a detailed balance, and gives self-consistent fluctuation mechanisms whose noise is asymptotically identical to the microscopic MC. Rigorous, detailed asymptotics justify and clarify these connections. Gradient continuous time microscopic MC and CGMC simulations are compared under far from equilibrium conditions to illustrate the validity of our theory and delineate the errors obtained by rigorous asymptotics. Information theory estimates are employed for the first time to provide rigorous error estimates between the solutions of microscopic MC and CGMC, describing the loss of information during the coarse-graining process. Simulations under periodic boundary conditions are used to verify the information theory error estimates. It is shown that coarse-graining in space leads also to coarse-graining in time by q2, where q is the level of coarse-graining, and overcomes in part the hydrodynamic slowdown. Operation counting and CGMC simulations demonstrate significant CPU savings in continuous time MC simulations that vary from q3 for short potentials to q4 for long potentials. Finally, connections of the new coarse-grained stochastic processes to stochastic mesoscopic and Cahn-Hilliard-Cook models are made.

Conservative and dissipative force field for simulation of coarse-grained alkane molecules: A bottom-up approach

Energy Technology Data Exchange (ETDEWEB)

Trément, Sébastien; Rousseau, Bernard, E-mail: bernard.rousseau@u-psud.fr [Laboratoire de Chimie-Physique, UMR 8000 CNRS, Université Paris-Sud, Orsay (France); Schnell, Benoît; Petitjean, Laurent; Couty, Marc [Manufacture Française des Pneumatiques MICHELIN, Centre de Ladoux, 23 place des Carmes, 63000 Clermont-Ferrand (France)

2014-04-07

We apply operational procedures available in the literature to the construction of coarse-grained conservative and friction forces for use in dissipative particle dynamics (DPD) simulations. The full procedure rely on a bottom-up approach: large molecular dynamics trajectories of n-pentane and n-decane modeled with an anisotropic united atom model serve as input for the force field generation. As a consequence, the coarse-grained model is expected to reproduce at least semi-quantitatively structural and dynamical properties of the underlying atomistic model. Two different coarse-graining levels are studied, corresponding to five and ten carbon atoms per DPD bead. The influence of the coarse-graining level on the generated force fields contributions, namely, the conservative and the friction part, is discussed. It is shown that the coarse-grained model of n-pentane correctly reproduces self-diffusion and viscosity coefficients of real n-pentane, while the fully coarse-grained model for n-decane at ambient temperature over-predicts diffusion by a factor of 2. However, when the n-pentane coarse-grained model is used as a building block for larger molecule (e.g., n-decane as a two blobs model), a much better agreement with experimental data is obtained, suggesting that the force field constructed is transferable to large macro-molecular systems.

Adaptive resolution simulation of polarizable supramolecular coarse-grained water models

International Nuclear Information System (INIS)

Zavadlav, Julija; Praprotnik, Matej; Melo, Manuel N.; Marrink, Siewert J.

2015-01-01

Multiscale simulations methods, such as adaptive resolution scheme, are becoming increasingly popular due to their significant computational advantages with respect to conventional atomistic simulations. For these kind of simulations, it is essential to develop accurate multiscale water models that can be used to solvate biophysical systems of interest. Recently, a 4-to-1 mapping was used to couple the bundled-simple point charge water with the MARTINI model. Here, we extend the supramolecular mapping to coarse-grained models with explicit charges. In particular, the two tested models are the polarizable water and big multiple water models associated with the MARTINI force field. As corresponding coarse-grained representations consist of several interaction sites, we couple orientational degrees of freedom of the atomistic and coarse-grained representations via a harmonic energy penalty term. This additional energy term aligns the dipole moments of both representations. We test this coupling by studying the system under applied static external electric field. We show that our approach leads to the correct reproduction of the relevant structural and dynamical properties

Coarse particles-water mixtures flow in pipes

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel

2017-01-01

Roč. 225, č. 2017 (2017), s. 338-341 ISSN 2411-3336 R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : hydrotransport * coarse particles pipeline installation * pressure drop * pipe inclination Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics)

Magnesium nutrition of apple trees. III. Comparison of different methods of magnesium fertilization

Directory of Open Access Journals (Sweden)

A. Sadowski

2015-06-01

Full Text Available In the period 1969-1973 two experiments were performed in young orchards in Central Poland: a four-year experiment at Julianów, on sandy loamy soil on underlying sand and one-year experiment at Kośmin, on sandy loam soil on clay loam. At Kosmin, in spite of a high Mg content in the subsoil, Mg deficiency symptoms appeared, because of shallow rooting owing to poor aeration. In both experiments, foliar sprays with epsomite were less effective than fertilization to the soil; at Kośmin even eight sprays were less effective than soil dressings. Mg losses from a sandy soil due to leaching were high, particularly where sand was present in the whole profile; under these conditions the least losses of Mg were from split doses of epsomite (Mg3x120. Single doses of epsomite were the most effective in increasing leaf Mg content, reducing Mg deficiency symptoms and promoting growth of trees in the first year after application; in the later years split doses of epsomite and a single initial dose of magnesium lime were more effective. Effects of Mg fertilization on growth and yields of apples were rather slight, when K fertilizer doses were low. No effect of Mg fertilization upon fruit drop and fruit quality was found. Preliminary recommendations for practice are given.

Inhibition effect of zinc in wastewater on the N2O emission from coastal loam soils.

Science.gov (United States)

Huang, Yan; Ou, Danyun; Chen, Shunyang; Chen, Bin; Liu, Wenhua; Bai, Renao; Chen, Guangcheng

2017-03-15

The effects of zinc (Zn) on nitrous oxide (N 2 O) fluxes from coastal loam soil and the abundances of soil nitrifier and denitrifier were studied in a tidal microcosm receiving livestock wastewater with different Zn levels. Soil N 2 O emission significantly increased due to discharge of wastewater rich in ammonia (NH 4 + -N) while the continuous measurements of gas flux showed a durative reduction in N 2 O flux by high Zn input (40mgL -1 ) during the low tide period. Soil inorganic nitrogen concentrations increased at the end of the experiment and even more soil NH 4 + -N was measured in the high-Zn-level treatment, indicating an inhibition of ammonia oxidation by Zn input. Quantitative PCR of soil amoA, narG and nirK genes encoding ammonia monooxygenase, nitrate reductase and nitrite reductase, respectively, showed that the microbial abundances involved in these metabolisms were neither affected by wastewater discharge nor Zn contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coarse-mesh discretized low-order quasi-diffusion equations for subregion averaged scalar fluxes

International Nuclear Information System (INIS)

Anistratov, D. Y.

2004-01-01

In this paper we develop homogenization procedure and discretization for the low-order quasi-diffusion equations on coarse grids for core-level reactor calculations. The system of discretized equations of the proposed method is formulated in terms of the subregion averaged group scalar fluxes. The coarse-mesh solution is consistent with a given fine-mesh discretization of the transport equation in the sense that it preserves a set of average values of the fine-mesh transport scalar flux over subregions of coarse-mesh cells as well as the surface currents, and eigenvalue. The developed method generates numerical solution that mimics the large-scale behavior of the transport solution within assemblies. (authors)

Characteristics of fine and coarse particles of natural and urban aerosols of Brazil

International Nuclear Information System (INIS)

Orsini, C.M.Q.; Tabacniks, M.H.; Artaxo Netto, P.E.; Andrade, M.F.; Kerr, A.

1986-02-01

Fine and coarse particles have been sampled from 1982 to 1985 in one natural forest seacoast site (Jureia) and five urban-industrial cities (Vitoria, Salvador, Porto Alegre, Sao Paulo, and Belo Horizonte). The time variations of concentrations in air and the relative elemental compositions of fine and coarse particle fractions, sampled by Nuclepore stacked filter units (SFU), have been determined gravimetrically and by PIXE analysis, respectively. Enrichment factors and correlation coefficients of the trace elements measured lead to unambiguous characterization of soil dust and sea salt, both major aerosol sources that emit coarse particles, and soil dust is also a significant source of fine particles. (Author) [pt

Effects of coarse-graining on the scaling behavior of long-range correlated and anti-correlated signals.

Science.gov (United States)

Xu, Yinlin; Ma, Qianli D Y; Schmitt, Daniel T; Bernaola-Galván, Pedro; Ivanov, Plamen Ch

2011-11-01

We investigate how various coarse-graining (signal quantization) methods affect the scaling properties of long-range power-law correlated and anti-correlated signals, quantified by the detrended fluctuation analysis. Specifically, for coarse-graining in the magnitude of a signal, we consider (i) the Floor, (ii) the Symmetry and (iii) the Centro-Symmetry coarse-graining methods. We find that for anti-correlated signals coarse-graining in the magnitude leads to a crossover to random behavior at large scales, and that with increasing the width of the coarse-graining partition interval Δ, this crossover moves to intermediate and small scales. In contrast, the scaling of positively correlated signals is less affected by the coarse-graining, with no observable changes when Δ 1 a crossover appears at small scales and moves to intermediate and large scales with increasing Δ. For very rough coarse-graining (Δ > 3) based on the Floor and Symmetry methods, the position of the crossover stabilizes, in contrast to the Centro-Symmetry method where the crossover continuously moves across scales and leads to a random behavior at all scales; thus indicating a much stronger effect of the Centro-Symmetry compared to the Floor and the Symmetry method. For coarse-graining in time, where data points are averaged in non-overlapping time windows, we find that the scaling for both anti-correlated and positively correlated signals is practically preserved. The results of our simulations are useful for the correct interpretation of the correlation and scaling properties of symbolic sequences.

FROM ATOMISTIC TO SYSTEMATIC COARSE-GRAINED MODELS FOR MOLECULAR SYSTEMS

KAUST Repository

Harmandaris, Vagelis

2017-10-03

The development of systematic (rigorous) coarse-grained mesoscopic models for complex molecular systems is an intense research area. Here we first give an overview of methods for obtaining optimal parametrized coarse-grained models, starting from detailed atomistic representation for high dimensional molecular systems. Different methods are described based on (a) structural properties (inverse Boltzmann approaches), (b) forces (force matching), and (c) path-space information (relative entropy). Next, we present a detailed investigation concerning the application of these methods in systems under equilibrium and non-equilibrium conditions. Finally, we present results from the application of these methods to model molecular systems.

ELASTOPLASTICIDAD DE UN SUELO FRANCO ARENOSO DE SABANA I SANDY LOAM SAVANNA SOIL ELASTOPLASTICITY

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Américo Hossne García

2018-04-01

Full Text Available The knowledge of elastoplastic properties is important for calculating soil elastic and plastic deformations experienced by static or dynamic loads generated, for example, by farm implements and root growth. The objective of this study was to determine the soil elastoplastic parameters: Young’s modulus (E, the shear modulus (G, bulk modulus (K and Poisson’s ratio (υ of a sandy-loam soil from a savanna in Monagas State, Venezuela. Triaxial tests and regression analyses were used to interpret the variance between them. The results show that E varied from 4693.39 to 36669.35 kPa; G from 700 to 5000 kPa; K from 500 to 2000 kPa and υ had a value of 0.50. It is concluded that these soils are incompressible under plastic conditions, i.e. easily deformable. The Poisson’s ratio varied significantly with soil water content. The Young modulus, bulk modulus and the shear modulus showed high variation with respect to water content. Both the Young’s modulus and Poisson’s ratio increased, at low soil water content, with the rise in chamber pressure .

Fine-coarse semantic processing in schizophrenia: a reversed pattern of hemispheric dominance.

Science.gov (United States)

Zeev-Wolf, Maor; Goldstein, Abraham; Levkovitz, Yechiel; Faust, Miriam

2014-04-01

Left lateralization for language processing is a feature of neurotypical brains. In individuals with schizophrenia, lack of left lateralization is associated with the language impairments manifested in this population. Beeman׳s fine-coarse semantic coding model asserts left hemisphere specialization in fine (i.e., conventionalized) semantic coding and right hemisphere specialization in coarse (i.e., non-conventionalized) semantic coding. Applying this model to schizophrenia would suggest that language impairments in this population are a result of greater reliance on coarse semantic coding. We investigated this hypothesis and examined whether a reversed pattern of hemispheric involvement in fine-coarse semantic coding along the time course of activation could be detected in individuals with schizophrenia. Seventeen individuals with schizophrenia and 30 neurotypical participants were presented with two word expressions of four types: literal, conventional metaphoric, unrelated (exemplars of fine semantic coding) and novel metaphoric (an exemplar of coarse semantic coding). Expressions were separated by either a short (250 ms) or long (750 ms) delay. Findings indicate that whereas during novel metaphor processing, controls displayed a left hemisphere advantage at 250 ms delay and right hemisphere advantage at 750 ms, individuals with schizophrenia displayed the opposite. For conventional metaphoric and unrelated expressions, controls showed left hemisphere advantage across times, while individuals with schizophrenia showed a right hemisphere advantage. Furthermore, whereas individuals with schizophrenia were less accurate than control at judging literal, conventional metaphoric and unrelated expressions they were more accurate when judging novel metaphors. Results suggest that individuals with schizophrenia display a reversed pattern of lateralization for semantic coding which causes them to rely more heavily on coarse semantic coding. Thus, for individuals with

Formulation of coarse mesh finite difference to calculate mathematical adjoint flux

International Nuclear Information System (INIS)

Pereira, Valmir; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

2002-01-01

The objective of this work is the obtention of the mathematical adjoint flux, having as its support the nodal expansion method (NEM) for coarse mesh problems. Since there are difficulties to evaluate this flux by using NEM. directly, a coarse mesh finite difference program was developed to obtain this adjoint flux. The coarse mesh finite difference formulation (DFMG) adopted uses results of the direct calculation (node average flux and node face averaged currents) obtained by NEM. These quantities (flux and currents) are used to obtain the correction factors which modify the classical finite differences formulation . Since the DFMG formulation is also capable of calculating the direct flux it was also tested to obtain this flux and it was verified that it was able to reproduce with good accuracy both the flux and the currents obtained via NEM. In this way, only matrix transposition is needed to calculate the mathematical adjoint flux. (author)

Coarse mode aerosols in the High Arctic

Science.gov (United States)

Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

2014-12-01

Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

Effect of Coarse Aggregate and Slag Type on the Mechanical Behavior of High and Normal Weight Concrete Used at Barrage Structure

Directory of Open Access Journals (Sweden)

Muhammad Sanaullah

2017-04-01

Full Text Available Present study is an effort to assess the composite effect of limestone aggregate and blast furnace slag on the mechanical characteristics of normal and high weight concrete at various structural units (barrage girders, main weir and block apron of New Khanki Barrage Project, Punjab. Mix designs for different concrete classes falling under the domain of high and normal weight concrete were prepared after aggregate quality testing. On attaining satisfactory results of quality testing nine concrete mixes were designed (three for each class: A1, A and B by absolute volume method (ACI- 211.1. The required compressive strength of normal and high strength was set at 6200, 5200 and 4200 Psi for the concrete types A1, A and B respectively after 28 days (ACI -318. For compressive strength assessment, a total 27 concrete cylinders were casted (9-cylinders for each mix and were water cured. The achieved average UCS of cylinder concrete specimens at 3, 7 and 28 days are 5170, 6338 and 7320 Psi for A1 – type, 3210, 4187 and 5602 Psi for A-type and 2650, 3360 and 4408 Psi for B- type mix. It has been found that all concrete mixes for suggested classes attained target strength at age of 7-days. The coarse aggregate (Margala Hill limestone and fine aggregates (from Lawrancepur /Qibla Bandi quarries used in all concrete mix designs have demonstrated a sound mechanical suitability for high and normal weight concrete.

Coarse mesh code development

Energy Technology Data Exchange (ETDEWEB)

Lieberoth, J.

1975-06-15

The numerical solution of the neutron diffusion equation plays a very important role in the analysis of nuclear reactors. A wide variety of numerical procedures has been proposed, at which most of the frequently used numerical methods are fundamentally based on the finite- difference approximation where the partial derivatives are approximated by the finite difference. For complex geometries, typical of the practical reactor problems, the computational accuracy of the finite-difference method is seriously affected by the size of the mesh width relative to the neutron diffusion length and by the heterogeneity of the medium. Thus, a very large number of mesh points are generally required to obtain a reasonably accurate approximate solution of the multi-dimensional diffusion equation. Since the computation time is approximately proportional to the number of mesh points, a detailed multidimensional analysis, based on the conventional finite-difference method, is still expensive even with modern large-scale computers. Accordingly, there is a strong incentive to develop alternatives that can reduce the number of mesh-points and still retain accuracy. One of the promising alternatives is the finite element method, which consists of the expansion of the neutron flux by piecewise polynomials. One of the advantages of this procedure is its flexibility in selecting the locations of the mesh points and the degree of the expansion polynomial. The small number of mesh points of the coarse grid enables to store the results of several of the least outer iterations and to calculate well extrapolated values of them by comfortable formalisms. This holds especially if only one energy distribution of fission neutrons is assumed for all fission processes in the reactor, because the whole information of an outer iteration is contained in a field of fission rates which has the size of all mesh points of the coarse grid.

MT-ADRES: multi-threading on coarse-grained reconfigurable architecture

DEFF Research Database (Denmark)

Wu, Kehuai; Kanstein, Andreas; Madsen, Jan

2008-01-01

The coarse-grained reconfigurable architecture ADRES (architecture for dynamically reconfigurable embedded systems) and its compiler offer high instruction-level parallelism (ILP) to applications by means of a sparsely interconnected array of functional units and register files. As high-ILP archi......The coarse-grained reconfigurable architecture ADRES (architecture for dynamically reconfigurable embedded systems) and its compiler offer high instruction-level parallelism (ILP) to applications by means of a sparsely interconnected array of functional units and register files. As high......-ILP architectures achieve only low parallelism when executing partially sequential code segments, which is also known as Amdahl's law, this article proposes to extend ADRES to MT-ADRES (multi-threaded ADRES) to also exploit thread-level parallelism. On MT-ADRES architectures, the array can be partitioned...

Experimental Investigations of Effect of Sulphur on Beach Sand–Fly Ash–Asphalt (S-F-A) Paving Mixes

OpenAIRE

Satyakumar, M.; Satheeshchandran, R.

2013-01-01

The main components of the flexible pavements are asphalt and aggregates. But in most of the places in India there is shortage of the good quality aggregates (especially coarse aggregates), at the same time beach sand is available in plenty in many regions. Due to relative abundance of beach sand, the studies on the utilities of the beach sand in paving mixes are worth taking up. But beach Sand-Asphalt mix alone is not suitable for pavement construction, because of its low stability and high ...

Superplastic behavior of coarse-grained aluminum alloys

NARCIS (Netherlands)

Chezan, AR; De Hosson, JTM

2005-01-01

In this paper we concentrate on the superplastic behavior and the microstructural evolution of two coarse-grained Al alloys: Al-4.4w/oMg and Al-4.4w/oMg-0.4w/oCu. The values for the strain rate sensitivity index and activation energy suggest that solute drag on dislocation motion is an important

Movement of Cryptosporidium parvum Oocysts through Soils without Preferential Pathways: Exploratory Test

Directory of Open Access Journals (Sweden)

Christophe J. G. Darnault

2017-06-01

Full Text Available Groundwater contamination by oocysts of the waterborne pathogen Cryptosporidium parvum is a significant cause of animal and human disease worldwide. Although research has been undertaken in the past to determine how specific physical and chemical properties of soils affect the risk of groundwater contamination by C. parvum, there is as yet no clear conclusion concerning the range of mobility of C. parvum that one should expect in field soils. In this context, the key objective of this research was to determine the magnitude of C. parvum transport in a number of soils, under conditions in which fast and preferential transport has been successfully prevented. C. parvum oocysts were applied at the surface of different soils and subjected to artificial rainfall. Apparently for the first time, quantitative PCR was used to detect and enumerate oocysts in the soil columns and in the leachates. The transport of oocysts by infiltrating water, and the considerable retention of oocysts in soil was demonstrated for all soils, although differences in the degree of transport were observed with soils of different types. More oocysts were found in leachates from sandy loam soils than in leachates from loamy sand soils and the retention of oocysts in different soils did not significantly differ. The interaction of various processes of the hydrologic system and biogeochemical mechanisms contributed to the transport of oocysts through the soil matrix. Results suggest that the interplay of clay, organic matter, and Ca2+ facilitates and mediates the transfer of organic matter from mineral surfaces to oocysts surface, resulting in the enhanced breakthrough of oocysts through matrices of sandy loam soils compared to those of loamy sand soils. Although the number of occysts that penetrate the soil matrix account for only a small percentage of initial inputs, they still pose a significant threat to human health, especially in groundwater systems with a water table not

Symmetries and the coarse-mesh method

International Nuclear Information System (INIS)

Makai, M.

1980-10-01

This report approaches the basic problem of the coarse-mesh method from a new side. Group theory is used for the determination of the space dependency of the flux. The result is a method called ANANAS after the analytic-analytic solution. This method was tested on two benchmark problems: one given by Melice and the IAEA benchmark. The ANANAS program is an experimental one. The method was intended for use in hexagonal geometry. (Auth.)

Enhancement of properties of recycled coarse aggregate concrete using bacteria

Science.gov (United States)

Sahoo; Arakha; Sarkar; P; Jha

2016-01-01

Due to rapid construction, necessity for raw materials of concrete, especially coarse aggregate, tends to increase the danger of early exhaustion of the natural resources. An alternative source of raw materials would perhaps delay the advent of this early exhaustion. Recycled coarse aggregate (RCA) plays a great role as an alternative raw material that can replace the natural coarse aggregate (NCA) for concrete. Previous studies show that the properties of RCA concrete are inferior in quality compared to NCA concrete. This article attempts to study the improvement of properties of RCA concrete with the addition of bacteria named as Bacillus subtilis. The experimental investigation was carried out to evaluate the improvement of the compressive strength, capillary water absorption, and drying shrinkage of RCA concrete incorporating bacteria. The compressive strength of RCA concrete is found to be increased by about 20% when the cell concentration of B. subtilis is 106 cells/ml. The capillary water absorption as well as drying shrinkage of RCA are reduced when bacteria is incorporated. The improvement of RCA concrete is confirmed to be due to the calcium carbonate precipitation as observed from the microstructure studies carried out on it such as EDX, SEM, and XRD.

Probabilistic risk assessment of nitrate groundwater contamination from greenhouses in Albenga plain (Liguria, Italy) using lysimeters.

Science.gov (United States)

Paladino, Ombretta; Seyedsalehi, Mahdi; Massabò, Marco

2018-04-05

The use of fertilizers in greenhouse-grown crops can pose a threat to groundwater quality and, consequently, to human beings and subterranean ecosystem, where intensive farming produces pollutants leaching. Albenga plain (Liguria, Italy) is an alluvial area of about 45km 2 historically devoted to farming. Recently the crops have evolved to greenhouses horticulture and floriculture production. In the area high levels of nitrates in groundwater have been detected. Lysimeters with three types of reconstituted soils (loamy sand, sandy clay loam and sandy loam) collected from different areas of Albenga plain were used in this study to evaluate the leaching loss of nitrate (NO 3 - ) over a period of 12weeks. Leaf lettuce (Lactuca sativa L.) was selected as a representative green-grown crop. Each of the soil samples was treated with a slow release fertilizer, simulating the real fertilizing strategy of the tillage. In order to estimate the potential risk for aquifers as well as for organisms exposed via pore water, nitrate concentrations in groundwater were evaluated by applying a simplified attenuation model to the experimental data. Results were refined and extended from comparison of single effects and exposure values (Tier I level) up to the evaluation of probabilistic distributions of exposure and related effects (Tier II, III IV levels). HHRA suggested HI >1 and about 20% probability of exceeding RfD for all the greenhouses, regardless of the soil. ERA suggested HQ>100 for all the greenhouses; 93% probability of PNEC exceedance for greenhouses containing sand clay loam. The probability of exceeding LC50 for 5% of the species was about 40% and the probability corresponding to DBQ of DEC/EC50>0.001 was >90% for all the greenhouses. The significantly high risk, related to the detected nitrate leaching loss, can be attributed to excessive and inappropriate fertigation strategies. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterizing protein conformations by correlation analysis of coarse-grained contact matrices

Science.gov (United States)

Lindsay, Richard J.; Siess, Jan; Lohry, David P.; McGee, Trevor S.; Ritchie, Jordan S.; Johnson, Quentin R.; Shen, Tongye

2018-01-01

We have developed a method to capture the essential conformational dynamics of folded biopolymers using statistical analysis of coarse-grained segment-segment contacts. Previously, the residue-residue contact analysis of simulation trajectories was successfully applied to the detection of conformational switching motions in biomolecular complexes. However, the application to large protein systems (larger than 1000 amino acid residues) is challenging using the description of residue contacts. Also, the residue-based method cannot be used to compare proteins with different sequences. To expand the scope of the method, we have tested several coarse-graining schemes that group a collection of consecutive residues into a segment. The definition of these segments may be derived from structural and sequence information, while the interaction strength of the coarse-grained segment-segment contacts is a function of the residue-residue contacts. We then perform covariance calculations on these coarse-grained contact matrices. We monitored how well the principal components of the contact matrices is preserved using various rendering functions. The new method was demonstrated to assist the reduction of the degrees of freedom for describing the conformation space, and it potentially allows for the analysis of a system that is approximately tenfold larger compared with the corresponding residue contact-based method. This method can also render a family of similar proteins into the same conformational space, and thus can be used to compare the structures of proteins with different sequences.

A detection of the coarse water droplets in steam turbines

Directory of Open Access Journals (Sweden)

Bartoš Ondřej

2014-03-01

Full Text Available The aim of this paper is to introduce a novel method for the detection of coarse water droplets in a low pressure part of steam turbines. The photogrammetry method has been applied for the measurement of coarse droplets in the low-pressure part of a steam turbine. A new probe based on this measurement technique was developed and tested in the laboratory and in a steam turbine in the Počerady power-plant. The probe was equipped with state-of-the-art instrumentation. The paper contains results from laboratory tests and the first preliminary measurements in a steam turbine. Possible applications of this method have been examined.

Modification of the MORSE code for Monte Carlo eigenvalue problems by coarse-mesh rebalance acceleration

International Nuclear Information System (INIS)

Nishida, Takahiko; Horikami, Kunihiko; Suzuki, Tadakazu; Nakahara, Yasuaki; Taji, Yukichi

1975-09-01

The coarse-mesh rebalancing technique is introduced into the general-purpose neutron and gamma-ray Monte Carlo transport code MORSE, to accelerate the convergence rate of the iteration process for eigenvalue calculation in a nuclear reactor system. Two subroutines are thus attached to the code. One is bookkeeping routine 'COARSE' for obtaining the quantities related with the neutron balance in each coarse mesh cell, such as the number of neutrons absorbed in the cell, from random walks of neutrons in a batch. The other is rebalance factor calculation routine 'REBAL' for obtaining the scaling factor whereby the neutron flux in the cell is multiplied to attain the neutron balance. The two subroutines and algorithm of the coarse mesh rebalancing acceleration in a Monte Carlo game are described. (auth.)

Martini Coarse-Grained Force Field : Extension to Carbohydrates

NARCIS (Netherlands)

Lopez, Cesar A.; Rzepiela, Andrzej J.; de Vries, Alex H.; Dijkhuizen, Lubbert; Huenenberger, Philippe H.; Marrink, Siewert J.

2009-01-01

We present an extension of the Martini coarse-grained force field to carbohydrates. The parametrization follows the same philosophy as was used previously for lipids and proteins, focusing on the reproduction of partitioning free energies of small compounds between polar and nonpolar phases. The

A study of the influence of coarse aggregate shape characteristics on permanent deformation of asphalt mixes

CSIR Research Space (South Africa)

Mabuse, MM

2013-07-01

Full Text Available The effect of aggregate shape properties such as angularity, texture, sphericity, roundness, flat and elongation on the performance of asphalt mixes have not been thoroughly investigated using direct measurement techniques. This is partly because...

Texture coarseness responsive neurons and their mapping in layer 2–3 of the rat barrel cortex in vivo

Science.gov (United States)

Garion, Liora; Dubin, Uri; Rubin, Yoav; Khateb, Mohamed; Schiller, Yitzhak; Azouz, Rony; Schiller, Jackie

2014-01-01

Texture discrimination is a fundamental function of somatosensory systems, yet the manner by which texture is coded and spatially represented in the barrel cortex are largely unknown. Using in vivo two-photon calcium imaging in the rat barrel cortex during artificial whisking against different surface coarseness or controlled passive whisker vibrations simulating different coarseness, we show that layer 2–3 neurons within barrel boundaries differentially respond to specific texture coarsenesses, while only a minority of neurons responded monotonically with increased or decreased surface coarseness. Neurons with similar preferred texture coarseness were spatially clustered. Multi-contact single unit recordings showed a vertical columnar organization of texture coarseness preference in layer 2–3. These findings indicate that layer 2–3 neurons perform high hierarchical processing of tactile information, with surface coarseness embodied by distinct neuronal subpopulations that are spatially mapped onto the barrel cortex. DOI: http://dx.doi.org/10.7554/eLife.03405.001 PMID:25233151

Performance of two bioswales on urban runoff management

Science.gov (United States)

Qingfu Xiao; E. McPherson; Qi Zhang; Xinlei Ge; Randy Dahlgren

2017-01-01

This study evaluated the effectiveness of two bioswales eight years after construction in Davis, California. The treatment bioswale measured 9 m × 1 m × 1 m (L × W × D). Engineered soil mix (75% native lava rock and 25% loam soil) replaced the native loam soil. Four Red Tip Photinia (Photinia × fraseri Dress) trees and two Blueberry Muffin Hawthorn...

Surface Runoff of Pesticides from a Clay Loam Field in Sweden.

Science.gov (United States)

Larsbo, Mats; Sandin, Maria; Jarvis, Nick; Etana, Ararso; Kreuger, Jenny

2016-07-01

Pesticides stored at or close to the soil surface after field application can be mobilized and transported off the field when surface runoff occurs. The objective of our study was to quantify the potential pesticide losses in surface runoff from a conventionally managed agricultural field in a Swedish climate. This was achieved by measuring surface runoff volumes and concentrations in runoff of six spring-applied pesticides and autumn-applied glyphosate and its metabolite aminomethylphosphonic acid (AMPA). Measurements were performed for 3 yr both during the growing seasons and during intervening winter snowmelt periods on a clay loam field close to Uppsala. During growing seasons, surface runoff was generated on only five occasions during one 25-d period in 2012 when the infiltration capacity of the soil may have been reduced by structural degradation due to large cumulative rainfall amounts after harrowing. Concentrations in surface runoff exceeded Swedish water quality standards in all samples during this growing season for diflufenican and pirimicarb. Surface runoff was generated during three snowmelt periods during the winter of 2012-2013. All of the applied pesticides were found in snowmelt samples despite incorporation of residues by autumn plowing, degradation, and leaching into the soil profile during the period between spraying and sampling. Concentrations of glyphosate ranged from 0.12 to 7.4 μg L, and concentrations of AMPA ranged from 0 to 2.7 μg L. Our results indicate that temporal changes in hydraulic properties during the growing season and when the soil freezes during winter affect pesticide losses through surface runoff. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Coupling a nano-particle with isothermal fluctuating hydrodynamics: Coarse-graining from microscopic to mesoscopic dynamics

Energy Technology Data Exchange (ETDEWEB)

Español, Pep [Dept. Física Fundamental, Universidad Nacional de Educación a Distancia, Aptdo. 60141, E-28080 Madrid (Spain); Donev, Aleksandar [Dept. Física Fundamental, Universidad Nacional de Educación a Distancia, Aptdo. 60141, E-28080 Madrid (Spain); Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, New York 10012 (United States)

2015-12-21

We derive a coarse-grained description of the dynamics of a nanoparticle immersed in an isothermal simple fluid by performing a systematic coarse graining of the underlying microscopic dynamics. As coarse-grained or relevant variables, we select the position of the nanoparticle and the total mass and momentum density field of the fluid, which are locally conserved slow variables because they are defined to include the contribution of the nanoparticle. The theory of coarse graining based on the Zwanzing projection operator leads us to a system of stochastic ordinary differential equations that are closed in the relevant variables. We demonstrate that our discrete coarse-grained equations are consistent with a Petrov-Galerkin finite-element discretization of a system of formal stochastic partial differential equations which resemble previously used phenomenological models based on fluctuating hydrodynamics. Key to this connection between our “bottom-up” and previous “top-down” approaches is the use of the same dual orthogonal set of linear basis functions familiar from finite element methods (FEMs), both as a way to coarse-grain the microscopic degrees of freedom and as a way to discretize the equations of fluctuating hydrodynamics. Another key ingredient is the use of a “linear for spiky” weak approximation which replaces microscopic “fields” with a linear FE interpolant inside expectation values. For the irreversible or dissipative dynamics, we approximate the constrained Green-Kubo expressions for the dissipation coefficients with their equilibrium averages. Under suitable approximations, we obtain closed approximations of the coarse-grained dynamics in a manner which gives them a clear physical interpretation and provides explicit microscopic expressions for all of the coefficients appearing in the closure. Our work leads to a model for dilute nanocolloidal suspensions that can be simulated effectively using feasibly short molecular dynamics

Impact of the Superpave hot mix asphalt properties on its permanent deformation behavior

Directory of Open Access Journals (Sweden)

Qasim Zahra

2018-01-01

Full Text Available In Iraq, the severity of rutting has increased in asphalt pavements possibly due to the increase in truck axle loads, tyre pressure, and high pavement temperature in summer. As of late, Superpave has been accounted as an enhanced system for performance based design, analysis of asphalt pavement performance prediction for asphalt concrete mixes. In this research the development of permanent deformation in asphalt concrete under repeated loadings was investigated, Wheel-Tracking apparatus has been used in a factorial testing program during which 44 slab samples were tested to simulate actual pavement. The objectives of the present research include; investigating the main factors affecting rutting in asphalt concrete mixture, quantifying the effect of SBS polymer and steel reinforcement on asphalt concrete mixtures in addition to studying the effect of variables on the asphalt concrete mixes against moisture sensitivity. It has been determined that that increasing of compaction temperature from 110 to 150°C will decrease the permanent deformation by 20.5 and 15.6 percent for coarse and fine gradation control asphalt mixtures, respectively. While the permanent deformation decreases by 21.3 percent when the compaction temperature is increased from 110 to 150°C for coarse gradation SBS modified asphalt mixtures.

Development of a stranded oil in coarse sediment (SOCS) model

International Nuclear Information System (INIS)

Humphrey, B.; Owens, E.; Sergy, G.

1993-01-01

Oil spills in Canadian waters have a high probability of impacting coarse sediment beaches, yet the ability to predict oil fate and estimate natural self-cleaning rates is less than adequate. Data is lacking to understand fully many oil sediment interactions. Historically, shoreline interactions have been considered using fairly simple concepts. The authors examined the processes that may occur on a coarse sediment beach, selected those which are important, and developed a fate and persistence model for stranded oil. The processes were divided into stages relative to the spill event, and the factors which affect each stage were evaluated. Three areas of special interest were the capacity of a beach to hold oil, the residual capacity of a beach for oil, and the long-term fate of the oil. After developing model algorithms, the outputs were compared to a data base of information collected during the Exxon Valdez oil spill. The stranded oil in coarse sediment model will provide information at two levels: a general level for planning and sensitivity mapping and a more detailed level intended for the prediction of oil fate on specific known beaches. The strengths and weaknesses of the model have been assessed in terms of data deficiencies. The type and nature of the data which are most useful to, and which need to be collected for, spill planning and spill monitoring were identified. The model shows that the important factors directing the fate of oil on coarse sediment beaches are porosity and permeability, determined by grain size and oil properties (composition, viscosity, etc.). The natural rate of removal of oil, modeled as a first-order (exponential) removal, is dependent on the stage of the spill process and on wave energy

Biochar effects on wet and dry regions of the soil water retention curve of a sandy loam

DEFF Research Database (Denmark)

Arthur, Emmanuel; Moldrup, Per; Sun, Zhencai

2014-01-01

Reported beneficial effects of biochar on soil physical properties and processes include decreased soil density, and increased soil water transport, water holding capacity and retention (mainly for the wet region). Research is limited on biochar effects on the full soil water retention curve (wet...... and dry regions) for a given soil and biochar amendment scenarios. This study evaluates how biochar applied to a sandy loam field at rates from 0 to 50 Mg ha−1 yr–1 in 2011, 2012, or both years (2011+2012) influences the full water retention curve. Inorganic fertilizer and pig slurry were added to all...... treatments. Six months after the last biochar application, intact and disturbed soil samples were collected for analyses. Soil water retention was measured from −1 kPa to −100 kPa using tension tables and ceramic plates and from −10 MPa to −480 MPa using a Vapor Sorption Analyzer. Soil specific area...

Martini Coarse-Grained Force Field : Extension to RNA

NARCIS (Netherlands)

Uusitalo, Jaakko J.; Ingolfsson, Helgi I.; Marrink, Siewert J.; Faustino, Ignacio

2017-01-01

RNA has an important role not only as the messenger of genetic information but also as a regulator of gene expression. Given its central role in cell biology, there is significant interest in studying the structural and dynamic behavior of RNA in relation to other biomolecules. Coarse-grain

Effect on Non-Newtonian Rheology on Mixing in Taylor-Couette Flow

Science.gov (United States)

Cagney, Neil; Balabani, Stavroula

2017-11-01

Mixing processes within many industry applications are strongly affected by the rheology of the working fluid. This is particularly relevant for pharmaceutical, food and waste treatment industries, where the working fluids are often strongly non-Newtonian, and significant variations in rheology between batches may occur. We approach the question of how rheology affects mixing by focussing on a the classical case of Taylor-Couette flow, which exhibits a number of instabilities and flow regimes as a function of Reynolds number. We examine Taylor-Couette flow generated for a range of aqueous solutions of xantham gum or corn starch, such that the rheology varies from shear-thinning to shear-thickening. For each case, we measure the power consumption using a torque meter and the flow field using high speed, time-resolved Particle-Image Velocimetry. The mixing characteristics are quantified using a number of Lagrangian and Eulerian approaches, including the coarse grained density method and vortex strength. By comparing these metrics to the power number, we discuss how the mixing efficiency (ratio of mixing effectiveness to power input) varies with the flow index of the fluid.

Changes to soil water content and biomass yield under combined maize and maize-weed vegetation with different fertilization treatments in loam soil

Directory of Open Access Journals (Sweden)

Lehoczky Éva

2016-06-01

Full Text Available Especially during early developmental stages, competition with weeds can reduce crop growth and have a serious effect on productivity. Here, the effects of interactions between soil water content (SWC, nutrient availability, and competition from weeds on early stage crop growth were investigated, to better understand this problem. Field experiments were conducted in 2013 and 2014 using long-term study plots on loam soil in Hungary. Plots of maize (Zea mays L. and a weed-maize combination were exposed to five fertilization treatments. SWC was observed along the 0–80 cm depth soil profile and harvested aboveground biomass (HAB was measured.

Moving beyond Watson-Crick models of coarse grained DNA dynamics.

Science.gov (United States)

Linak, Margaret C; Tourdot, Richard; Dorfman, Kevin D

2011-11-28

DNA produces a wide range of structures in addition to the canonical B-form of double-stranded DNA. Some of these structures are stabilized by Hoogsteen bonds. We developed an experimentally parameterized, coarse-grained model that incorporates such bonds. The model reproduces many of the microscopic features of double-stranded DNA and captures the experimental melting curves for a number of short DNA hairpins, even when the open state forms complicated secondary structures. We demonstrate the utility of the model by simulating the folding of a thrombin aptamer, which contains G-quartets, and strand invasion during triplex formation. Our results highlight the importance of including Hoogsteen bonding in coarse-grained models of DNA.

The Andatza coarse-grained turbidite system (westernmost Pyrenees: Stratigraphy, sedimentology and structural control

Directory of Open Access Journals (Sweden)

A. Bodego

2017-06-01

Full Text Available This is a field-based work that describes the stratigraphy and sedimentology of the Andatza Conglomerate Formation. Based on facies analysis three facies associations of a coarse-grained turbidite system and the related slope have been identified: (1 an inner fan of a turbidite system (or canyon and (2 a low- and (3 a high-gradient muddy slope respectively. The spatial distribution of the facies associations and the palaeocurrent analysis allow to interpret a depositional model for the Andatza Conglomerates consisting of an L-shaped, coarse-grained turbidite system, whose morphology was structurally controlled by synsedimentary basement-involved normal faults. The coarse-grained character of the turbidite system indicates the proximity of the source area, with the presence of a narrow shelf that fed the turbidite canyon from the north.

Separation and collection of coarse aggregate from waste concrete by electric pulsed power

Science.gov (United States)

Shigeishi, Mitsuhiro

2017-09-01

Waste concrete accounts for a substantial fraction of construction waste, and the recycling of waste concrete as concrete aggregate for construction is an important challenge associated with the rapid increase in the amount of waste concrete and the tight supply of natural aggregate. In this study, we propose a technique based on the use of high-voltage pulsed electric discharge into concrete underwater for separating and collecting aggregate from waste concrete with minimal deterioration of quality. By using this technique, the quality of the coarse aggregate separated and collected from concrete test specimens is comparable to that of coarse aggregate recycled by heating and grinding methods, thus satisfying the criteria in Japan Industrial Standard (JIS) A 5021 for the oven-dry density and the water absorption of coarse aggregate by advanced recycling.

Exact CTP renormalization group equation for the coarse-grained effective action

International Nuclear Information System (INIS)

Dalvit, D.A.; Mazzitelli, F.D.

1996-01-01

We consider a scalar field theory in Minkowski spacetime and define a coarse-grained closed time path (CTP) effective action by integrating quantum fluctuations of wavelengths shorter than a critical value. We derive an exact CTP renormalization group equation for the dependence of the effective action on the coarse-graining scale. We solve this equation using a derivative expansion approach. Explicit calculation is performed for the λφ 4 theory. We discuss the relevance of the CTP average action in the study of nonequilibrium aspects of phase transitions in quantum field theory. copyright 1996 The American Physical Society

Coarse-grained simulations of polyelectrolyte complexes: MARTINI models for poly(styrene sulfonate) and poly(diallyldimethylammonium)

Energy Technology Data Exchange (ETDEWEB)

Vögele, Martin [Institute for Computational Physics, University of Stuttgart, Stuttgart (Germany); Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt a. M. (Germany); Holm, Christian; Smiatek, Jens, E-mail: smiatek@icp.uni-stuttgart.de [Institute for Computational Physics, University of Stuttgart, Stuttgart (Germany)

2015-12-28

We present simulations of aqueous polyelectrolyte complexes with new MARTINI models for the charged polymers poly(styrene sulfonate) and poly(diallyldimethylammonium). Our coarse-grained polyelectrolyte models allow us to study large length and long time scales with regard to chemical details and thermodynamic properties. The results are compared to the outcomes of previous atomistic molecular dynamics simulations and verify that electrostatic properties are reproduced by our MARTINI coarse-grained approach with reasonable accuracy. Structural similarity between the atomistic and the coarse-grained results is indicated by a comparison between the pair radial distribution functions and the cumulative number of surrounding particles. Our coarse-grained models are able to quantitatively reproduce previous findings like the correct charge compensation mechanism and a reduced dielectric constant of water. These results can be interpreted as the underlying reason for the stability of polyelectrolyte multilayers and complexes and validate the robustness of the proposed models.

Coarse-grained simulations of polyelectrolyte complexes: MARTINI models for poly(styrene sulfonate) and poly(diallyldimethylammonium)

International Nuclear Information System (INIS)

Vögele, Martin; Holm, Christian; Smiatek, Jens

2015-01-01

We present simulations of aqueous polyelectrolyte complexes with new MARTINI models for the charged polymers poly(styrene sulfonate) and poly(diallyldimethylammonium). Our coarse-grained polyelectrolyte models allow us to study large length and long time scales with regard to chemical details and thermodynamic properties. The results are compared to the outcomes of previous atomistic molecular dynamics simulations and verify that electrostatic properties are reproduced by our MARTINI coarse-grained approach with reasonable accuracy. Structural similarity between the atomistic and the coarse-grained results is indicated by a comparison between the pair radial distribution functions and the cumulative number of surrounding particles. Our coarse-grained models are able to quantitatively reproduce previous findings like the correct charge compensation mechanism and a reduced dielectric constant of water. These results can be interpreted as the underlying reason for the stability of polyelectrolyte multilayers and complexes and validate the robustness of the proposed models

The Influence Of Loam Type And Cement Content On The Compressive Strength Of Rammed Earth

Directory of Open Access Journals (Sweden)

Narloch P. L.

2015-03-01

Full Text Available Currently, a worldwide dynamic rise of interest in using soil as a construction material can be observed. This trend is evident in the rapid rise of the amount of standards that deal with soil techniques. In 2012 the number of standards was larger by one third than five years prior. To create a full standardization of the rammed earth technique it is necessary to take into account the diversity of used soil and stabilizing additives. The proportion of the components, the process of element production and the research methods must also be made uniform. The article describes the results of research on the compressive strength of rammed earth samples that differed from each other with regards to the type of loam used for the mixture and the amount of the stabilizer. The stabilizer used was Portland cement CEM I 42.5R. The research and the analysis of the results were based on foreign publications, the New Zealand standard NZS 4298:1998, the American Standard NMAC14.7.4 and archival Polish Standards from the 1960’s that dealt with earth material.

Measuring Crack Length in Coarse Grain Ceramics

Science.gov (United States)

Salem, Jonathan A.; Ghosn, Louis J.

2010-01-01

Due to a coarse grain structure, crack lengths in precracked spinel specimens could not be measured optically, so the crack lengths and fracture toughness were estimated by strain gage measurements. An expression was developed via finite element analysis to correlate the measured strain with crack length in four-point flexure. The fracture toughness estimated by the strain gaged samples and another standardized method were in agreement.

Solvation free energies and partition coefficients with the coarse-grained and hybrid all-atom/coarse-grained MARTINI models.

Science.gov (United States)

Genheden, Samuel

2017-10-01

We present the estimation of solvation free energies of small solutes in water, n-octanol and hexane using molecular dynamics simulations with two MARTINI models at different resolutions, viz. the coarse-grained (CG) and the hybrid all-atom/coarse-grained (AA/CG) models. From these estimates, we also calculate the water/hexane and water/octanol partition coefficients. More than 150 small, organic molecules were selected from the Minnesota solvation database and parameterized in a semi-automatic fashion. Using either the CG or hybrid AA/CG models, we find considerable deviations between the estimated and experimental solvation free energies in all solvents with mean absolute deviations larger than 10 kJ/mol, although the correlation coefficient is between 0.55 and 0.75 and significant. There is also no difference between the results when using the non-polarizable and polarizable water model, although we identify some improvements when using the polarizable model with the AA/CG solutes. In contrast to the estimated solvation energies, the estimated partition coefficients are generally excellent with both the CG and hybrid AA/CG models, giving mean absolute deviations between 0.67 and 0.90 log units and correlation coefficients larger than 0.85. We analyze the error distribution further and suggest avenues for improvements.

Solvation free energies and partition coefficients with the coarse-grained and hybrid all-atom/coarse-grained MARTINI models

Science.gov (United States)

Genheden, Samuel

2017-10-01

We present the estimation of solvation free energies of small solutes in water, n-octanol and hexane using molecular dynamics simulations with two MARTINI models at different resolutions, viz. the coarse-grained (CG) and the hybrid all-atom/coarse-grained (AA/CG) models. From these estimates, we also calculate the water/hexane and water/octanol partition coefficients. More than 150 small, organic molecules were selected from the Minnesota solvation database and parameterized in a semi-automatic fashion. Using either the CG or hybrid AA/CG models, we find considerable deviations between the estimated and experimental solvation free energies in all solvents with mean absolute deviations larger than 10 kJ/mol, although the correlation coefficient is between 0.55 and 0.75 and significant. There is also no difference between the results when using the non-polarizable and polarizable water model, although we identify some improvements when using the polarizable model with the AA/CG solutes. In contrast to the estimated solvation energies, the estimated partition coefficients are generally excellent with both the CG and hybrid AA/CG models, giving mean absolute deviations between 0.67 and 0.90 log units and correlation coefficients larger than 0.85. We analyze the error distribution further and suggest avenues for improvements.

Recycled tires as coarse aggregate in concrete pavement mixtures.

Science.gov (United States)

2013-07-01

The reuse potential of tire chips as coarse aggregates in pavement concrete was examined in this research by : investigating the effects of low- and high-volume tire chips on fresh and hardened concrete properties. One concrete : control mixture was ...

Closed depression topography and Harps soil, revisited

Science.gov (United States)

The Harps soil (Fine-loamy, mixed superactive, mesic Typic Calciaquoll) developed around wetland depressions. The purpose of this study is 1) to delineate surface deposition of carbonates representing Harps soil which results from outward and upward flow around closed depressions, and 2) to relate t...

Non-Steady Oscillatory Flow in Coarse Granular Materials

DEFF Research Database (Denmark)

Andersen, O. H.; Gent, M. R. A. van; Meer, J. W. van der

1992-01-01

Stationary and oscillatory flow through coarse granular materials have been investigated experimentally at Delft Hydraulics in their oscillating water tunnel with the objective of determining the coefficients of the extended Forchheimer equation. Cylinders, spheres and different types of rock have....... Further, for the non-stationary term, the virtual mass coefficient will be derived....

Loop overhead reduction techniques for coarse grained reconfigurable architectures

NARCIS (Netherlands)

Vadivel, K.; Wijtvliet, M.; Jordans, R.; Corporaal, H.

2017-01-01

Due to their flexibility and high performance, Coarse Grained Reconfigurable Array (CGRA) are a topic of increasing research interest. However, CGRAs also have the potential to achieve very high energy efficiency in comparison to other reconfigurable architectures when hardware optimizations are

Hierarchical coarse-graining transform.

Science.gov (United States)

Pancaldi, Vera; King, Peter R; Christensen, Kim

2009-03-01

We present a hierarchical transform that can be applied to Laplace-like differential equations such as Darcy's equation for single-phase flow in a porous medium. A finite-difference discretization scheme is used to set the equation in the form of an eigenvalue problem. Within the formalism suggested, the pressure field is decomposed into an average value and fluctuations of different kinds and at different scales. The application of the transform to the equation allows us to calculate the unknown pressure with a varying level of detail. A procedure is suggested to localize important features in the pressure field based only on the fine-scale permeability, and hence we develop a form of adaptive coarse graining. The formalism and method are described and demonstrated using two synthetic toy problems.

A coarse-graining approach for molecular simulation that retains the dynamics of the all-atom reference system by implementing hydrodynamic interactions

Energy Technology Data Exchange (ETDEWEB)

Markutsya, Sergiy [Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States); Lamm, Monica H., E-mail: mhlamm@iastate.edu [Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States); Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2014-11-07

We report on a new approach for deriving coarse-grained intermolecular forces that retains the frictional contribution that is often discarded by conventional coarse-graining methods. The approach is tested for water and an aqueous glucose solution, and the results from the new implementation for coarse-grained molecular dynamics simulation show remarkable agreement with the dynamics obtained from reference all-atom simulations. The agreement between the structural properties observed in the coarse-grained and all-atom simulations is also preserved. We discuss how this approach may be applied broadly to any existing coarse-graining method where the coarse-grained models are rigorously derived from all-atom reference systems.

A coarse-graining approach for molecular simulation that retains the dynamics of the all-atom reference system by implementing hydrodynamic interactions

International Nuclear Information System (INIS)

Markutsya, Sergiy; Lamm, Monica H.

2014-01-01

We report on a new approach for deriving coarse-grained intermolecular forces that retains the frictional contribution that is often discarded by conventional coarse-graining methods. The approach is tested for water and an aqueous glucose solution, and the results from the new implementation for coarse-grained molecular dynamics simulation show remarkable agreement with the dynamics obtained from reference all-atom simulations. The agreement between the structural properties observed in the coarse-grained and all-atom simulations is also preserved. We discuss how this approach may be applied broadly to any existing coarse-graining method where the coarse-grained models are rigorously derived from all-atom reference systems

Variational multiscale enrichment method with mixed boundary conditions for elasto-viscoplastic problems

Science.gov (United States)

Zhang, Shuhai; Oskay, Caglar

2015-04-01

This manuscript presents the formulation and implementation of the variational multiscale enrichment (VME) method for the analysis of elasto-viscoplastic problems. VME is a global-local approach that allows accurate fine scale representation at small subdomains, where important physical phenomena are likely to occur. The response within far-fields is idealized using a coarse scale representation. The fine scale representation not only approximates the coarse grid residual, but also accounts for the material heterogeneity. A one-parameter family of mixed boundary conditions that range from Dirichlet to Neumann is employed to study the effect of the choice of the boundary conditions at the fine scale on accuracy. The inelastic material behavior is modeled using Perzyna type viscoplasticity coupled with flow stress evolution idealized by the Johnson-Cook model. Numerical verifications are performed to assess the performance of the proposed approach against the direct finite element simulations. The results of verification studies demonstrate that VME with proper boundary conditions accurately model the inelastic response accounting for material heterogeneity.

Mixed Far-Field and Near-Field Source Localization Algorithm via Sparse Subarrays

Directory of Open Access Journals (Sweden)

Jiaqi Song

2018-01-01

Full Text Available Based on a dual-size shift invariance sparse linear array, this paper presents a novel algorithm for the localization of mixed far-field and near-field sources. First, by constructing a cumulant matrix with only direction-of-arrival (DOA information, the proposed algorithm decouples the DOA estimation from the range estimation. The cumulant-domain quarter-wavelength invariance yields unambiguous estimates of DOAs, which are then used as coarse references to disambiguate the phase ambiguities in fine estimates induced from the larger spatial invariance. Then, based on the estimated DOAs, another cumulant matrix is derived and decoupled to generate unambiguous and cyclically ambiguous estimates of range parameter. According to the coarse range estimation, the types of sources can be identified and the unambiguous fine range estimates of NF sources are obtained after disambiguation. Compared with some existing algorithms, the proposed algorithm enjoys extended array aperture and higher estimation accuracy. Simulation results are given to validate the performance of the proposed algorithm.

Climatic regions as an indicator of forest coarse and fine woody debris carbon stocks in the United States

Directory of Open Access Journals (Sweden)

Liknes Greg C

2008-06-01

Full Text Available Abstract Background Coarse and fine woody debris are substantial forest ecosystem carbon stocks; however, there is a lack of understanding how these detrital carbon stocks vary across forested landscapes. Because forest woody detritus production and decay rates may partially depend on climatic conditions, the accumulation of coarse and fine woody debris carbon stocks in forests may be correlated with climate. This study used a nationwide inventory of coarse and fine woody debris in the United States to examine how these carbon stocks vary by climatic regions and variables. Results Mean coarse and fine woody debris forest carbon stocks vary by Köppen's climatic regions across the United States. The highest carbon stocks were found in regions with cool summers while the lowest carbon stocks were found in arid desert/steppes or temperate humid regions. Coarse and fine woody debris carbon stocks were found to be positively correlated with available moisture and negatively correlated with maximum temperature. Conclusion It was concluded with only medium confidence that coarse and fine woody debris carbon stocks may be at risk of becoming net emitter of carbon under a global climate warming scenario as increases in coarse or fine woody debris production (sinks may be more than offset by increases in forest woody detritus decay rates (emission. Given the preliminary results of this study and the rather tenuous status of coarse and fine woody debris carbon stocks as either a source or sink of CO2, further research is suggested in the areas of forest detritus decay and production.

Influence of N,K and CaSO4 on utilisation of sulfur by rice in red sandy loam soil

International Nuclear Information System (INIS)

Patnaik, M.C.; Sathe, Arun

1993-01-01

A greenhouse study with rice on red sandy loam soil showed that uptake of sulphur increased from both native as well as applied source with increase in the application of sulphur from 20-60 kg S ha -1 through gypsum. The grain yields were influenced by nitrogen application but there was only relative increase with the application of potassium and sulphur. There was positive effect of applied nitrogen and sulphur for the total sulphur removal by the rice crop. The per cent sulphur utilisation decreased with increase in sulphur application from 20-60 kg S ha -1 through gypsum but increased with increase in the application of nitrogen from 0-150 kg N ha -1 . Sulphur utilization by rice crop was more in potassium treated pots compared to that without its application. (author). 7 refs., 3 tabs

Effects of Model Resolution and Ocean Mixing on Forced Ice-Ocean Physical and Biogeochemical Simulations Using Global and Regional System Models

Science.gov (United States)

Jin, Meibing; Deal, Clara; Maslowski, Wieslaw; Matrai, Patricia; Roberts, Andrew; Osinski, Robert; Lee, Younjoo J.; Frants, Marina; Elliott, Scott; Jeffery, Nicole; Hunke, Elizabeth; Wang, Shanlin

2018-01-01

The current coarse-resolution global Community Earth System Model (CESM) can reproduce major and large-scale patterns but is still missing some key biogeochemical features in the Arctic Ocean, e.g., low surface nutrients in the Canada Basin. We incorporated the CESM Version 1 ocean biogeochemical code into the Regional Arctic System Model (RASM) and coupled it with a sea-ice algal module to investigate model limitations. Four ice-ocean hindcast cases are compared with various observations: two in a global 1° (40˜60 km in the Arctic) grid: G1deg and G1deg-OLD with/without new sea-ice processes incorporated; two on RASM's 1/12° (˜9 km) grid R9km and R9km-NB with/without a subgrid scale brine rejection parameterization which improves ocean vertical mixing under sea ice. Higher-resolution and new sea-ice processes contributed to lower model errors in sea-ice extent, ice thickness, and ice algae. In the Bering Sea shelf, only higher resolution contributed to lower model errors in salinity, nitrate (NO3), and chlorophyll-a (Chl-a). In the Arctic Basin, model errors in mixed layer depth (MLD) were reduced 36% by brine rejection parameterization, 20% by new sea-ice processes, and 6% by higher resolution. The NO3 concentration biases were caused by both MLD bias and coarse resolution, because of excessive horizontal mixing of high NO3 from the Chukchi Sea into the Canada Basin in coarse resolution models. R9km showed improvements over G1deg on NO3, but not on Chl-a, likely due to light limitation under snow and ice cover in the Arctic Basin.

Management of parthenium weed by extracts and residue of wheat

African Journals Online (AJOL)

Ehsan Zaidi

2011-10-24

Oct 24, 2011 ... bioassay, dried and chopped wheat straw of the four test wheat varieties was thoroughly mixed in pot ... environment from living plants and the subsequent ... Copped materials were mixed in sandy loam soil in plastic pots of 8.

Free-energy coarse-grained potential for C60

International Nuclear Information System (INIS)

Edmunds, D. M.; Tangney, P.; Vvedensky, D. D.; Foulkes, W. M. C.

2015-01-01

We propose a new deformable free energy method for generating a free-energy coarse-graining potential for C 60 . Potentials generated from this approach exhibit a strong temperature dependence and produce excellent agreement with benchmark fully atomistic molecular dynamics simulations. Parameter sets for analytical fits to this potential are provided at four different temperatures

Systematic coarse-graining of the dynamics of entangled polymer melts: the road from chemistry to rheology

International Nuclear Information System (INIS)

Padding, J T; Briels, W J

2011-01-01

For optimal processing and design of entangled polymeric materials it is important to establish a rigorous link between the detailed molecular composition of the polymer and the viscoelastic properties of the macroscopic melt. We review current and past computer simulation techniques and critically assess their ability to provide such a link between chemistry and rheology. We distinguish between two classes of coarse-graining levels, which we term coarse-grained molecular dynamics (CGMD) and coarse-grained stochastic dynamics (CGSD). In CGMD the coarse-grained beads are still relatively hard, thus automatically preventing bond crossing. This also implies an upper limit on the number of atoms that can be lumped together (up to five backbone carbon atoms) and therefore on the longest chain lengths that can be studied. To reach a higher degree of coarse-graining, in CGSD many more atoms are lumped together (more than ten backbone carbon atoms), leading to relatively soft beads. In that case friction and stochastic forces dominate the interactions, and action must be undertaken to prevent bond crossing. We also review alternative methods that make use of the tube model of polymer dynamics, by obtaining the entanglement characteristics through a primitive path analysis and by simulation of a primitive chain network. We finally review super-coarse-grained methods in which an entire polymer is represented by a single particle, and comment on ways to include memory effects and transient forces. (topical review)

Fuel-steel mixing and radial mesh effects in power excursion simulations

International Nuclear Information System (INIS)

Chen, X.-N.; Rineiski, A.; Gabrielli, F.; Andriolo, L.; Vezzoni, B.; Li, R.; Maschek, W.; Kiefhaber, E.

2016-01-01

Highlights: • Fuel-steel mixing and radial mesh effects are significant on power excursion. • The earliest power peak is reduced and retarded by these two effects. • Unprotected loss of coolant transients in ESFR core are calculated. - Abstract: This paper deals with SIMMER-III once-through simulations of the earliest power excursion initiated by an unprotected loss of flow (ULOF) in the Working Horse design of the European Sodium Cooled Fast Reactor (ESFR). Since the sodium void effect is strictly positive in this core and dominant in the transient, a power excursion is initiated by sodium boiling in the ULOF case. Two major effects, namely (1) reactivity effects due to fuel-steel mixing after melting and (2) the radial mesh size, which were not considered originally in SIMMER simulations for ESFR, are studied. The first effect concerns the reactivity difference between the heterogeneous fuel/clad/wrapper configuration and the homogeneous mixture of steel and fuel. The full core homogenization (due to melting) effect is −2 $, though a smaller effect takes place in case of partial core melting. The second effect is due to the SIMMER sub-assembly (SA) coarse mesh treatment, where a simultaneous sodium boiling onset in all SAs belonging to one ring leads to an overestimated reactivity ramp. For investigating the influence of fuel/steel mixing effects, a lumped “homogenization” reactivity feedback has been introduced, being proportional to the molten steel mass. For improving the coarse mesh treatment, we employ finer radial meshes to take the subchannel effects into account, where the side and interior channels have different coolant velocities and temperatures. The simulation results show that these two effects have significant impacts on the earliest power excursion after the sodium boiling.

Field description of coarse bioclastic fabrics

Energy Technology Data Exchange (ETDEWEB)

Kidwell, S.M.; Holland, S.M. (Univ. of Chicago, IL (United States))

1991-08-01

Shell- and bone-bearing rocks can be readily categorized into 9 macroscopic fabric types using semi-quantitative scales for close-packing and size-sorting of bioclasts greater than 2 mm in diameter. Although designed to describe fossiliferous siliciclastics and volcaniclastics, this system of field description can also be used to enlarge upon standard petrographic descriptions of fossiliferous carbonates. In cross-sectional bed views, coarse bioclasts may be densely packed. These coarse bioclasts (>2 mm) may be well sorted (central 80% of bioclasts lie within 1 or 2 adjacent phi size-classes), bimodal (well sorted but with a distinct second mode), or poorly sorted (central 80% of bioclasts distributed over 3 or more adjacent size-classes). Despite the complicating effects of bioclast shape, novices show 90% accuracy in estimating close-packing from photographs. They have only 60% accuracy in estimating size-sorting (the most common error is underestimating goodness of sorting), underscoring the importance of size-tallies to cross-check visual estimates when first using this scheme. This packing/sorting approach provides a good visual image of the fabric, and narrows the range of possible modes of origin more than alternative criteria such as volumetric percent-abundance (which shows no one-to-one equivalence with close-packing), orientation, and fragmentation. However, detailed interpretations of fabrics usually require more information on these and other features of the deposit, including bioclast condition, associated sedimentary structures, life-habits of bioclast-producers, and stratigraphic context.

Early deterioration of coarse woody debris.

Energy Technology Data Exchange (ETDEWEB)

Tainter, Frank, H.; McMinn, James, W.

1999-02-16

Tainter, F.H., and J.W. McMinn. 1999. Early deterioration of coarse woody debris. In: Proc. Tenth Bien. South. Silv. Res. Conf. Shreveport, LA, February 16-18, 1999. Pp. 232-237 Abstract - Coarse woody debris (CWD) is an important structural component of southern forest ecosystems. CWD loading may be affected by different decomposition rates on sites of varying quality. Bolts of red oak and loblolly pine were placed on plots at each of three (hydric, mesic. and xerlc) sites at the Savannah River Site and sampled over a I6-week period. Major changes were in moisture content and nonstructural carbohydrate content (total carbohydrates, reducing sugars, and starch) of sapwood. Early changes in nonstructural carbohydrate levels following placement of the bolts were likely due to reallocation of these materials by sapwood parenchyma cells. These carbohydrates later formed pools increasingly metabolized by bacteria and invading fungi. Most prevalent fungi in sapwood were Ceratocysfis spp. in pine and Hypoxy/on spp. in oak. Although pine sapwood became blue stained and oak sapwood exhibited yellow soft decay with black zone lines, estimators of decay (specific gravity, sodium hydroxide solubility, and holocellulose content) were unchanged during the 16-week study period. A small effect of site was detected for starch content of sapwood of both species. Fungal biomass in sapwood of both species, as measured by ergosterol content, was detectable at week zero, increased somewhat by week three and increased significantly by week 16.

Effect of biochar amendment on nitrate retention in a silty clay loam soil

Directory of Open Access Journals (Sweden)

Angela Libutti

2016-08-01

Full Text Available Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control, soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (analysis of co-variance statistical approach. Nitrate retention in the soilbiochar mixtures was always higher than control, regardless the NO3 – concentration in the range of 0-400 mg L–1. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4% and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching.

Properties of Non-Structural Concrete Made with Mixed Recycled Aggregates and Low Cement Content.

Science.gov (United States)

López-Uceda, Antonio; Ayuso, Jesús; López, Martin; Jimenez, José Ramón; Agrela, Francisco; Sierra, María José

2016-01-26

In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA) could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i) to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement, on the mechanical and physical properties of a non-structural concrete made with a low cement content; and (ii) to verify if it is possible to achieve a low-strength concrete that replaces a greater amount of natural aggregate with MRA and that has a low cement content. Two series of concrete mixes were manufactured using 180 and 200 kg/m³ of CEM II/A-V 42.5 R type Portland cement. Each series included seven concrete mixes: one with natural aggregates; two MRA with different ceramic particle contents; and one for each coarse aggregate replacement ratio (20%, 40%, and 100%). To study their properties, compressive and splitting tensile strength, modulus of elasticity, density, porosity, water penetration, and sorptivity, tests were performed. The results confirmed that the main factors affecting the properties analyzed in this research are the amount of cement and the replacement ratio; the two MRAs used in this work presented a similar influence on the properties. A non-structural, low-strength concrete (15 MPa) with an MRA replacement ratio of up to 100% for 200 kg/m³ of cement was obtained. This type of concrete could be applied in the construction of ditches, sidewalks, and other similar civil works.

Time evolution as refining, coarse graining and entangling

International Nuclear Information System (INIS)

Dittrich, Bianca; Steinhaus, Sebastian

2014-01-01

We argue that refining, coarse graining and entangling operators can be obtained from time evolution operators. This applies in particular to geometric theories, such as spin foams. We point out that this provides a construction principle for the physical vacuum in quantum gravity theories and more generally allows construction of a (cylindrically) consistent continuum limit of the theory. (paper)

Time evolution as refining, coarse graining and entangling

Science.gov (United States)

Dittrich, Bianca; Steinhaus, Sebastian

2014-12-01

We argue that refining, coarse graining and entangling operators can be obtained from time evolution operators. This applies in particular to geometric theories, such as spin foams. We point out that this provides a construction principle for the physical vacuum in quantum gravity theories and more generally allows construction of a (cylindrically) consistent continuum limit of the theory.

Local free energies for the coarse-graining of adsorption phenomena: The interacting pair approximation

Science.gov (United States)

Pazzona, Federico G.; Pireddu, Giovanni; Gabrieli, Andrea; Pintus, Alberto M.; Demontis, Pierfranco

2018-05-01

We investigate the coarse-graining of host-guest systems under the perspective of the local distribution of pore occupancies, along with the physical meaning and actual computability of the coarse-interaction terms. We show that the widely accepted approach, in which the contributions to the free energy given by the molecules located in two neighboring pores are estimated through Monte Carlo simulations where the two pores are kept separated from the rest of the system, leads to inaccurate results at high sorbate densities. In the coarse-graining strategy that we propose, which is based on the Bethe-Peierls approximation, density-independent interaction terms are instead computed according to local effective potentials that take into account the correlations between the pore pair and its surroundings by means of mean-field correction terms without the need for simulating the pore pair separately. Use of the interaction parameters obtained this way allows the coarse-grained system to reproduce more closely the equilibrium properties of the original one. Results are shown for lattice-gases where the local free energy can be computed exactly and for a system of Lennard-Jones particles under the effect of a static confining field.

14C tebuconazole degradation in Colombian soils.

Science.gov (United States)

Mosquera, C S; Martínez, M J; Guerrero, J A

2010-01-01

Tebuconazole is a fungicide used on onion crops (Allium Fistulosum L) in Colombia. Persistence of pesticides in soils is characterized by the half-life (DT50), which is influenced by their chemical structure, the physical and chemical properties of the soil and the previous soil history. Based on its structural and chemical properties, tebuconazole should be expected to be relatively persistent in soils. Laboratory incubation studies were conducted to evaluate persistence and bond residues of 14C tebuconazole in three soils, two inceptisol (I) and one histosol (H). Textural classifications were: loam (101), loamy sand (102) and loam (H03), respectively. Data obtained followed a first-order degradation kinetics (R2 > or = 0.899) with DT50 values between 158 and 198 days. The production of 14CO2 from the 14C-ring-labelled test chemicals was very low and increased slightly during 63 days in all cases. The methanol extractable 14C-residues were higher than aqueous ones and both decreased over incubation time for the three soils. The formation of bound 14C-residues increased with time and final values were 11.3; 5.55 and 7.87% for 101, 102 and H03 respectively. Soil 101 showed the lowest mineralization rate and the highest bound residues formation, which might be explained by the clay fraction content. In contrast, an inverse behavior was found for soils 102 and H03, these results might be explained by the higher soil organic carbon content.

Boltzmann rovibrational collisional coarse-grained model for internal energy excitation and dissociation in hypersonic flows.

Science.gov (United States)

Munafò, A; Panesi, M; Magin, T E

2014-02-01

A Boltzmann rovibrational collisional coarse-grained model is proposed to reduce a detailed kinetic mechanism database developed at NASA Ames Research Center for internal energy transfer and dissociation in N(2)-N interactions. The coarse-grained model is constructed by lumping the rovibrational energy levels of the N(2) molecule into energy bins. The population of the levels within each bin is assumed to follow a Boltzmann distribution at the local translational temperature. Excitation and dissociation rate coefficients for the energy bins are obtained by averaging the elementary rate coefficients. The energy bins are treated as separate species, thus allowing for non-Boltzmann distributions of their populations. The proposed coarse-grained model is applied to the study of nonequilibrium flows behind normal shock waves and within converging-diverging nozzles. In both cases, the flow is assumed inviscid and steady. Computational results are compared with those obtained by direct solution of the master equation for the rovibrational collisional model and a more conventional multitemperature model. It is found that the proposed coarse-grained model is able to accurately resolve the nonequilibrium dynamics of internal energy excitation and dissociation-recombination processes with only 20 energy bins. Furthermore, the proposed coarse-grained model provides a superior description of the nonequilibrium phenomena occurring in shock heated and nozzle flows when compared with the conventional multitemperature models.

Utilization of Ripe Coconut Fiber in Stone Matrix Asphalt Mixes

Directory of Open Access Journals (Sweden)

Mahabir Panda

2013-12-01

Full Text Available Stone Matrix Asphalt (SMA is a gap graded mix; characterized by higher proportion of coarse aggregate, lower proportion of middle size aggregate and higher proportion of mineral filler. In the present laboratory study, commonly available one conventional VG 30 bitumen and another modified binder, namely CRMB 60 have been used along with a non-conventional natural fiber, namely coconut fiber which is abundantly available in India to provide improved engineering properties and at the same time preventing the usual draining of binder in SMA. The role of a particular binder and fiber with respect to their concentrations in the mix is studied for various engineering properties. Marshall procedure has been followed to determine the optimum binder and optimum fiber contents and also to study the relative advantages of fiber addition in the SMA mixtures. Thereafter, the engineering properties under both static as well as repeated load conditions and moisture susceptibility characteristics have been studied. It is observed that only a marginal 0.3% coconut fiber addition brings significant improvement in the engineering properties of SMA mixes.

Coarse-graining complex dynamics

DEFF Research Database (Denmark)

Sibani, Paolo

2013-01-01

Continuous Time Random Walks (CTRW) are widely used to coarse-grain the evolution of systems jumping from a metastable sub-set of their configuration space, or trap, to another via rare intermittent events. The multi-scaled behavior typical of complex dynamics is provided by a fat...... macroscopic variables all produce identical long time relaxation behaviors. Hence, CTRW shed no light on the link between microscopic and macroscopic dynamics. We then highlight how a more recent approach, Record Dynamics (RD) provides a viable alternative, based on a very different set of physical ideas......: while CTRW make use of a renewal process involving identical traps of infinite size, RD embodies a dynamical entrenchment into a hierarchy of traps which are finite in size and possess different degrees of meta-stability. We show in particular how RD produces the stretched exponential, power...

Information Theoretic Tools for Parameter Fitting in Coarse Grained Models

KAUST Repository

Kalligiannaki, Evangelia; Harmandaris, Vagelis; Katsoulakis, Markos A.; Plechac, Petr

2015-01-01

We study the application of information theoretic tools for model reduction in the case of systems driven by stochastic dynamics out of equilibrium. The model/dimension reduction is considered by proposing parametrized coarse grained dynamics

Abrasion and algal fouling of coarse material on the Murman littoral

Directory of Open Access Journals (Sweden)

Malavenda S. V.

2017-03-01

Full Text Available On the Murmansk coast of the Barents Sea the boulder littoral zone is widely spread mostly covered by Fucus communities. This is one of the most productive benthic communities of the Barents Sea. The studies of intertidal communities have the long history, but the dynamics of intertidal ecosystems due to surf and storms is not clear. The goal of the work is to identify the leading factors that determine the rate of abrasion of coarse material and fouling algae-macrophytes of the intertidal zone of Murman. The study has been conducted in the Zelenetskaya Bay of the Barents Sea on the basis of the biological station of the MMBI KSC RAS. The rate of abrasion has been carried out during 2004–2013, phyto-overgrowing – 2009–2013. In three pilot landfills 12 samples of coarse material have been exposed during the year (from July to next July. The weight change of the sample as well as species composition and biomass of algae of fouling communities have been investigated. The influence of the surf intensity, temperature of water and air has been analyzed (univariate analysis of variance ANOVA has been applied. It has been shown that on the littoral of the Murmansk coast the abrasion of coarse material is determined primarily by the number of storms, so the storm rate has been proposed. It has been revealed that the density of fouling boulders with macroalgae depends primarily on the intensity of the surf and the average gradient of air temperature. The basis for the emerging communities of annual species are green (Acrosiphonia arcta, Blidingia minima, Spongomorpha aeruginosa and brown algae (Pylaiella littoralis, Dictyosiphon chordaria. These algae groups are found everywhere in Fucus communities of the boulder intertidal zone of the Murman coast and probably they are the intermediate stage of fouling the coarse-grained material

Evaluation of Masonry Mortars Made with Mixed Recycled Aggregates by Different Processes

OpenAIRE

Iván Martínez Herrera; Miren Etxeberria Larrañaga; Elier Pavón de la Fé; Nelson Díaz Brito

2012-01-01

Havana produces over 1000 m3 of construction and demolition waste (CDW) per day. Most of these residues are of a mixed composition; they come either from collapsing buildings in disrepair or demolition that are not performed selectively. From the CDW, there are usually two ways to produce recycled aggregates; one is by sifting the debris through a 5mm sieve which is a practice widely used by residents in cities and the other from is by crushing the coarse fractions in recycled aggregate produ...

Premelting, fluctuations, and coarse-graining of water-ice interfaces

Energy Technology Data Exchange (ETDEWEB)

Limmer, David T., E-mail: dlimmer@princeton.edu [Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08540 (United States); Chandler, David [Department of Chemistry, University of California, Berkeley, California 94609 (United States)

2014-11-14

Using statistical field theory supplemented with molecular dynamics simulations, we consider premelting on the surface of ice as a generic consequence of broken hydrogen bonds at the boundary between the condensed and gaseous phases. A procedure for coarse-graining molecular configurations onto a continuous scalar order parameter field is discussed, which provides a convenient representation of the interface between locally crystal-like and locally liquid-like regions. A number of interfacial properties are straightforwardly evaluated using this procedure such as the average premelting thickness and surface tension. The temperature and system size dependence of the premelting layer thickness calculated in this way confirms the characteristic logarithmic growth expected for the scalar field theory that the system is mapped onto through coarse-graining, though remains finite due to long-ranged interactions. Finally, from explicit simulations the existence of a premelting layer is shown to be insensitive to bulk lattice geometry, exposed crystal face, and curvature.

Premelting, fluctuations, and coarse-graining of water-ice interfaces

Science.gov (United States)

Limmer, David T.; Chandler, David

2014-11-01

Using statistical field theory supplemented with molecular dynamics simulations, we consider premelting on the surface of ice as a generic consequence of broken hydrogen bonds at the boundary between the condensed and gaseous phases. A procedure for coarse-graining molecular configurations onto a continuous scalar order parameter field is discussed, which provides a convenient representation of the interface between locally crystal-like and locally liquid-like regions. A number of interfacial properties are straightforwardly evaluated using this procedure such as the average premelting thickness and surface tension. The temperature and system size dependence of the premelting layer thickness calculated in this way confirms the characteristic logarithmic growth expected for the scalar field theory that the system is mapped onto through coarse-graining, though remains finite due to long-ranged interactions. Finally, from explicit simulations the existence of a premelting layer is shown to be insensitive to bulk lattice geometry, exposed crystal face, and curvature.

Premelting, fluctuations, and coarse-graining of water-ice interfaces

International Nuclear Information System (INIS)

Limmer, David T.; Chandler, David

2014-01-01

Using statistical field theory supplemented with molecular dynamics simulations, we consider premelting on the surface of ice as a generic consequence of broken hydrogen bonds at the boundary between the condensed and gaseous phases. A procedure for coarse-graining molecular configurations onto a continuous scalar order parameter field is discussed, which provides a convenient representation of the interface between locally crystal-like and locally liquid-like regions. A number of interfacial properties are straightforwardly evaluated using this procedure such as the average premelting thickness and surface tension. The temperature and system size dependence of the premelting layer thickness calculated in this way confirms the characteristic logarithmic growth expected for the scalar field theory that the system is mapped onto through coarse-graining, though remains finite due to long-ranged interactions. Finally, from explicit simulations the existence of a premelting layer is shown to be insensitive to bulk lattice geometry, exposed crystal face, and curvature

Premelting, fluctuations, and coarse-graining of water-ice interfaces.

Science.gov (United States)

Limmer, David T; Chandler, David

2014-11-14

Using statistical field theory supplemented with molecular dynamics simulations, we consider premelting on the surface of ice as a generic consequence of broken hydrogen bonds at the boundary between the condensed and gaseous phases. A procedure for coarse-graining molecular configurations onto a continuous scalar order parameter field is discussed, which provides a convenient representation of the interface between locally crystal-like and locally liquid-like regions. A number of interfacial properties are straightforwardly evaluated using this procedure such as the average premelting thickness and surface tension. The temperature and system size dependence of the premelting layer thickness calculated in this way confirms the characteristic logarithmic growth expected for the scalar field theory that the system is mapped onto through coarse-graining, though remains finite due to long-ranged interactions. Finally, from explicit simulations the existence of a premelting layer is shown to be insensitive to bulk lattice geometry, exposed crystal face, and curvature.

MULCHING MATERIALS OF PLANT ORIGIN AT POTATO GROWING IN ASTRAKHAN REGION

Directory of Open Access Journals (Sweden)

S. B. Bairambekov

2016-01-01

Full Text Available The application of phytogenous mulching materials based on local processed raw materials at potato cultivation in irrigated conditions of the Astrakhan region has allowed optimization of temperature and moisture regime of the soil. It was found that in case of the spring term of planting, the mulching has increased the soil temperature up to 0,6-0,9°C on April-May at a depth of 0,10 m as compared to the control. During heat period, mulching materials have decreased the soil temperature. Antecedent soil water under mulching materials in the phase of tubers formation was on 1,15-1,19 times higher than in the control variant without mulching. The most effective materials for the soils of different grain-size distribution were determined: for the heavy-loamy soil the best mulching material was straw, for the sandy loam soil the more efficient mulching was saw-dust.

How ocean lateral mixing changes Southern Ocean variability in coupled climate models

Science.gov (United States)

Pradal, M. A. S.; Gnanadesikan, A.; Thomas, J. L.

2016-02-01

The lateral mixing of tracers represents a major uncertainty in the formulation of coupled climate models. The mixing of tracers along density surfaces in the interior and horizontally within the mixed layer is often parameterized using a mixing coefficient ARedi. The models used in the Coupled Model Intercomparison Project 5 exhibit more than an order of magnitude range in the values of this coefficient used within the Southern Ocean. The impacts of such uncertainty on Southern Ocean variability have remained unclear, even as recent work has shown that this variability differs between different models. In this poster, we change the lateral mixing coefficient within GFDL ESM2Mc, a coarse-resolution Earth System model that nonetheless has a reasonable circulation within the Southern Ocean. As the coefficient varies from 400 to 2400 m2/s the amplitude of the variability varies significantly. The low-mixing case shows strong decadal variability with an annual mean RMS temperature variability exceeding 1C in the Circumpolar Current. The highest-mixing case shows a very similar spatial pattern of variability, but with amplitudes only about 60% as large. The suppression of mixing is larger in the Atlantic Sector of the Southern Ocean relatively to the Pacific sector. We examine the salinity budgets of convective regions, paying particular attention to the extent to which high mixing prevents the buildup of low-saline waters that are capable of shutting off deep convection entirely.

Coarse mesh finite element method for boiling water reactor physics analysis

International Nuclear Information System (INIS)

Ellison, P.G.

1983-01-01

A coarse mesh method is formulated for the solution of Boiling Water Reactor physics problems using two group diffusion theory. No fuel assembly cross-section homogenization is required; water gaps, control blades and fuel pins of varying enrichments are treated explicitly. The method combines constrained finite element discretization with infinite lattice super cell trial functions to obtain coarse mesh solutions for which the only approximations are along the boundaries between fuel assemblies. The method is applied to bench mark Boiling Water Reactor problems to obtain both the eigenvalue and detailed flux distributions. The solutions to these problems indicate the method is useful in predicting detailed power distributions and eigenvalues for Boiling Water Reactor physics problems

Soil water retention, air flow and pore structure characteristics after corn cob biochar application to a tropical sandy loam

DEFF Research Database (Denmark)

Amoakwah, Emmanuel; Frimpong, Kwame Agyei; Okae-Anti, D

2017-01-01

Soil structure is a key soil physical property that affects soil water balance, gas transport, plant growth and development, and ultimately plant yield. Biochar has received global recognition as a soil amendment with the potential to ameliorate the structure of degraded soils. We investigated how...... corn cob biochar contributed to changes in soil water retention, air flow by convection and diffusion, and derived soil structure indices in a tropical sandy loam. Intact soil cores were taken from a field experiment that had plots without biochar (CT), and plots each with 10 t ha− 1 (BC-10), 20 t ha...... to significant increase in soil water retention compared to the CT and BC-10 as a result of increased microporosity (pores biochar had minimal impact. No significant influence of biochar was observed for ka and Dp/D0 for the BC treatments compared to the CT despite...

Variational approach to coarse-graining of generalized gradient flows

NARCIS (Netherlands)

Duong, M.H.; Lamacz, A.; Peletier, M.A.; Sharma, U.

2017-01-01

In this paper we present a variational technique that handles coarse-graining and passing to a limit in a unified manner. The technique is based on a duality structure, which is present in many gradient flows and other variational evolutions, and which often arises from a large-deviations principle.

The spectrum and occurrence of entomopathogenic fungi in soils from apple orchards

Directory of Open Access Journals (Sweden)

Barbara Marjańska-Cichoń

2012-12-01

Full Text Available The spectrum and occurrence of entomopathogenic fungi in orchard soil and arable soil were evaluated using an "insect bait method". Soil samples taken in autumn and spring from sward, herbicides fallow and arable soil were baited with Galleria mellonella larvae. Entomopathogenic fungi Beauveria bassiana (Bals. Vuill., Metarhizium anisopliae (Metsch. Sorok. and Paecilomyces fumosoroseus (Wize Brown et Smith were isolated from three species of orchards soil and adjacent arable soil. Infection levels of G. mellonella larvae were depended from species of soil . M. anisoopliae caused most frequent infections of bait insects in light loamy sand and P. fumosoroseus in alluvial silt and coarse sand. B. bassiana was dominated in alluvial silt. It was established that M. anisopliae and B. bassiana infected more larvae in autumn than in spring. In case of P. fumosoroseus an opposite tendency was observed. Generaly in arable soil and sward number of infected larvae was higher than other stands. In case of light loamy sand more infections of G. mellonella larvae were found in samples from herbicides fallow. Irrespective of soil type B. bassiana was the dominated species isolated from herbicides fallow, M. anisopliae from sward and P. fumosoroseus - from arable soil.

The geometry of generalized force matching and related information metrics in coarse-graining of molecular systems

International Nuclear Information System (INIS)

Kalligiannaki, Evangelia; Harmandaris, Vagelis; Katsoulakis, Markos A.; Plecháč, Petr

2015-01-01

Using the probabilistic language of conditional expectations, we reformulate the force matching method for coarse-graining of molecular systems as a projection onto spaces of coarse observables. A practical outcome of this probabilistic description is the link of the force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean force and to optimally approximate the potential of mean force through force matching. We introduce a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the generalized force matching condition through applications to specific examples in molecular systems

The geometry of generalized force matching and related information metrics in coarse-graining of molecular systems

Energy Technology Data Exchange (ETDEWEB)

Kalligiannaki, Evangelia, E-mail: ekalligian@tem.uoc.gr [Department of Mathematics and Applied Mathematics, University of Crete, 70013 Heraklion (Greece); Harmandaris, Vagelis, E-mail: harman@uoc.gr [Department of Mathematics and Applied Mathematics, University of Crete, 70013 Heraklion (Greece); Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), IACM/FORTH, GR-71110 Heraklion (Greece); Katsoulakis, Markos A., E-mail: markos@math.umass.edu [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Plecháč, Petr, E-mail: plechac@math.udel.edu [Department of Mathematical Sciences, University of Delaware, Newark, Delaware 19716 (United States)

2015-08-28

Using the probabilistic language of conditional expectations, we reformulate the force matching method for coarse-graining of molecular systems as a projection onto spaces of coarse observables. A practical outcome of this probabilistic description is the link of the force matching method with thermodynamic integration. This connection provides a way to systematically construct a local mean force and to optimally approximate the potential of mean force through force matching. We introduce a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (e.g., reaction coordinates, end-to-end length of chains). Furthermore, we study the equivalence of force matching with relative entropy minimization which we derive for general non-linear coarse graining maps. We present in detail the generalized force matching condition through applications to specific examples in molecular systems.

Spontaneous adsorption of coiled-coil model peptides K and E to a mixed lipid bilayer.

Science.gov (United States)

Pluhackova, Kristyna; Wassenaar, Tsjerk A; Kirsch, Sonja; Böckmann, Rainer A

2015-03-26

A molecular description of the lipid-protein interactions underlying the adsorption of proteins to membranes is crucial for understanding, for example, the specificity of adsorption or the binding strength of a protein to a bilayer, or for characterizing protein-induced changes of membrane properties. In this paper, we extend an automated in silico assay (DAFT) for binding studies and apply it to characterize the adsorption of the model fusion peptides E and K to a mixed phospholipid/cholesterol membrane using coarse-grained molecular dynamics simulations. In addition, we couple the coarse-grained protocol to reverse transformation to atomistic resolution, thereby allowing to study molecular interactions with high detail. The experimentally observed differential binding of the peptides E and K to membranes, as well as the increased binding affinity of helical over unstructered peptides, could be well reproduced using the polarizable Martini coarse-grained (CG) force field. Binding to neutral membranes is shown to be dominated by initial binding of the positively charged N-terminus to the phospholipid headgroup region, followed by membrane surface-aligned insertion of the peptide at the interface between the hydrophobic core of the membrane and its polar headgroup region. Both coarse-grained and atomistic simulations confirm a before hypothesized snorkeling of lysine side chains for the membrane-bound state of the peptide K. Cholesterol was found to be enriched in peptide vicinity, which is probably of importance for the mechanism of membrane fusion. The applied sequential multiscale method, using coarse-grained simulations for the slow adsorption process of peptides to membranes followed by backward transformation to atomistic detail and subsequent atomistic simulations of the preformed peptide-lipid complexes, is shown to be a versatile approach to study the interactions of peptides or proteins with biomembranes.

Coarse Point Cloud Registration by Egi Matching of Voxel Clusters

Science.gov (United States)

Wang, Jinhu; Lindenbergh, Roderik; Shen, Yueqian; Menenti, Massimo

2016-06-01

Laser scanning samples the surface geometry of objects efficiently and records versatile information as point clouds. However, often more scans are required to fully cover a scene. Therefore, a registration step is required that transforms the different scans into a common coordinate system. The registration of point clouds is usually conducted in two steps, i.e. coarse registration followed by fine registration. In this study an automatic marker-free coarse registration method for pair-wise scans is presented. First the two input point clouds are re-sampled as voxels and dimensionality features of the voxels are determined by principal component analysis (PCA). Then voxel cells with the same dimensionality are clustered. Next, the Extended Gaussian Image (EGI) descriptor of those voxel clusters are constructed using significant eigenvectors of each voxel in the cluster. Correspondences between clusters in source and target data are obtained according to the similarity between their EGI descriptors. The random sampling consensus (RANSAC) algorithm is employed to remove outlying correspondences until a coarse alignment is obtained. If necessary, a fine registration is performed in a final step. This new method is illustrated on scan data sampling two indoor scenarios. The results of the tests are evaluated by computing the point to point distance between the two input point clouds. The presented two tests resulted in mean distances of 7.6 mm and 9.5 mm respectively, which are adequate for fine registration.

Estimating the acute health effects of coarse particulate matter accounting for exposure measurement error.

Science.gov (United States)

Chang, Howard H; Peng, Roger D; Dominici, Francesca

2011-10-01

In air pollution epidemiology, there is a growing interest in estimating the health effects of coarse particulate matter (PM) with aerodynamic diameter between 2.5 and 10 μm. Coarse PM concentrations can exhibit considerable spatial heterogeneity because the particles travel shorter distances and do not remain suspended in the atmosphere for an extended period of time. In this paper, we develop a modeling approach for estimating the short-term effects of air pollution in time series analysis when the ambient concentrations vary spatially within the study region. Specifically, our approach quantifies the error in the exposure variable by characterizing, on any given day, the disagreement in ambient concentrations measured across monitoring stations. This is accomplished by viewing monitor-level measurements as error-prone repeated measurements of the unobserved population average exposure. Inference is carried out in a Bayesian framework to fully account for uncertainty in the estimation of model parameters. Finally, by using different exposure indicators, we investigate the sensitivity of the association between coarse PM and daily hospital admissions based on a recent national multisite time series analysis. Among Medicare enrollees from 59 US counties between the period 1999 and 2005, we find a consistent positive association between coarse PM and same-day admission for cardiovascular diseases.

Photo-polarimetric sensitivities to layering and mixing of absorbing aerosols

Directory of Open Access Journals (Sweden)

O. V. Kalashnikova

2011-09-01

Full Text Available We investigate to what extent multi-angle polarimetric measurements are sensitive to vertical mixing/layering of absorbing aerosols, adopting calibration uncertainty of 1.5% in intensity and 0.5% in the degree of linear polarization of Multiangle Spectro-Polarimetric Imager (MSPI. Employing both deterministic and Monte Carlo radiative transfer codes with polarization, we conduct modeling experiments to determine how the measured Stokes vector elements are affected at UV and short visible wavelengths by the vertical distribution, mixing and layering of smoke and dust aerosols for variety of microphysical parameters. We find that multi-angular polarimetry holds the potential to infer dust-layer heights and thicknesses at blue visible channel due to its lesser sensitivity to changes in dust coarse mode optical properties, but higher sensitivity to the dust vertical profiles. Our studies quantify requirements for obtaining simultaneous information on aerosol layer height and absorption under MSPI measurement uncertainties.

Peridynamics as a rigorous coarse-graining of atomistics for multiscale materials design

International Nuclear Information System (INIS)

Lehoucq, Richard B.; Aidun, John Bahram; Silling, Stewart Andrew; Sears, Mark P.; Kamm, James R.; Parks, Michael L.

2010-01-01

This report summarizes activities undertaken during FY08-FY10 for the LDRD Peridynamics as a Rigorous Coarse-Graining of Atomistics for Multiscale Materials Design. The goal of our project was to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. The goal of our project is to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. Our coarse-graining overcomes the intrinsic limitation of coupling atomistics with classical continuum mechanics via the FEM (finite element method), SPH (smoothed particle hydrodynamics), or MPM (material point method); namely, that classical continuum mechanics assumes a local force interaction that is incompatible with the nonlocal force model of atomistic methods. Therefore FEM, SPH, and MPM inherit this limitation. This seemingly innocuous dichotomy has far reaching consequences; for example, classical continuum mechanics cannot resolve the short wavelength behavior associated with atomistics. Other consequences include spurious forces, invalid phonon dispersion relationships, and irreconcilable descriptions/treatments of temperature. We propose a statistically based coarse-graining of atomistics via peridynamics and so develop a first of a kind mesoscopic capability to enable consistent, thermodynamically sound, atomistic-to-continuum (AtC) multiscale material simulation. Peridynamics (PD) is a microcontinuum theory that assumes nonlocal forces for describing long-range material interaction. The force interactions occurring at finite distances are naturally accounted for in PD. Moreover, PDs nonlocal force model is entirely consistent with those used by atomistics methods, in stark contrast to classical continuum mechanics. Hence, PD can be employed for mesoscopic phenomena that are beyond the realms of classical continuum mechanics and

Ill-posedness in modeling mixed sediment river morphodynamics

Science.gov (United States)

Chavarrías, Víctor; Stecca, Guglielmo; Blom, Astrid

2018-04-01

In this paper we analyze the Hirano active layer model used in mixed sediment river morphodynamics concerning its ill-posedness. Ill-posedness causes the solution to be unstable to short-wave perturbations. This implies that the solution presents spurious oscillations, the amplitude of which depends on the domain discretization. Ill-posedness not only produces physically unrealistic results but may also cause failure of numerical simulations. By considering a two-fraction sediment mixture we obtain analytical expressions for the mathematical characterization of the model. Using these we show that the ill-posed domain is larger than what was found in previous analyses, not only comprising cases of bed degradation into a substrate finer than the active layer but also in aggradational cases. Furthermore, by analyzing a three-fraction model we observe ill-posedness under conditions of bed degradation into a coarse substrate. We observe that oscillations in the numerical solution of ill-posed simulations grow until the model becomes well-posed, as the spurious mixing of the active layer sediment and substrate sediment acts as a regularization mechanism. Finally we conduct an eigenstructure analysis of a simplified vertically continuous model for mixed sediment for which we show that ill-posedness occurs in a wider range of conditions than the active layer model.

Disentangling the drivers of coarse woody debris behavior and carbon gas emissions during fire

Science.gov (United States)

Zhao, Weiwei; van der Werf, Guido R.; van Logtestijn, Richard S. P.; van Hal, Jurgen R.; Cornelissen, Johannes H. C.

2016-04-01

The turnover of coarse woody debris, a key terrestrial carbon pool, plays fundamental roles in global carbon cycling. Biological decomposition and fire are two main fates for dead wood turnover. Compared to slow decomposition, fire rapidly transfers organic carbon from the earth surface to the atmosphere. Both a-biotic environmental factors and biotic wood properties determine coarse wood combustion and thereby its carbon gas emissions during fire. Moisture is a key inhibitory environmental factor for fire. The properties of dead wood strongly affect how it burns either directly or indirectly through interacting with moisture. Coarse wood properties vary between plant species and between various decay stages. Moreover, if we put a piece of dead wood in the context of a forest fuel bed, the soil and wood contact might also greatly affect their fire behavior. Using controlled laboratory burns, we disentangled the effects of all these driving factors: tree species (one gymnosperms needle-leaf species, three angiosperms broad-leaf species), wood decay stages (freshly dead, middle decayed, very strongly decayed), moisture content (air-dried, 30% moisture content in mass), and soil-wood contact (on versus 3cm above the ground surface) on dead wood flammability and carbon gas efflux (CO2 and CO released in grams) during fire. Wood density was measured for all coarse wood samples used in our experiment. We found that compared to other drivers, wood decay stages have predominant positive effects on coarse wood combustion (for wood mass burned, R2=0.72 when air-dried and R2=0.52 at 30% moisture content) and associated carbon gas emissions (for CO2andCO (g) released, R2=0.55 when air-dried and R2=0.42 at 30% moisture content) during fire. Thus, wood decay accelerates wood combustion and its CO2 and CO emissions during fire, which can be mainly attributed to the decreasing wood density (for wood mass burned, R2=0.91 when air-dried and R2=0.63 at 30% moisture content) as wood

Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ model

Directory of Open Access Journals (Sweden)

J. T. Kelly

2010-04-01

. Modeled sodium concentration is biased low and causes under-prediction of coarse particle nitrate. Also, CMAQ over-predicts geometric mean diameter and standard deviation of particle modes at the BRACE sites. These over-predictions may cause too rapid particle dry deposition and partially explain the low bias in sodium predictions. Despite these shortcomings, the updates to CMAQ enable more realistic simulations of chemical processes in environments where marine air mixes with urban pollution. The model updates described in this article are included in the public release of CMAQv4.7 (http://www.cmaq-model.org.

Root-cause analysis of the better performance of the coarse-mesh finite-difference method for CANDU-type reactors

International Nuclear Information System (INIS)

Shen, W.

2012-01-01

Recent assessment results indicate that the coarse-mesh finite-difference method (FDM) gives consistently smaller percent differences in channel powers than the fine-mesh FDM when compared to the reference MCNP solution for CANDU-type reactors. However, there is an impression that the fine-mesh FDM should always give more accurate results than the coarse-mesh FDM in theory. To answer the question if the better performance of the coarse-mesh FDM for CANDU-type reactors was just a coincidence (cancellation of errors) or caused by the use of heavy water or the use of lattice-homogenized cross sections for the cluster fuel geometry in the diffusion calculation, three benchmark problems were set up with three different fuel lattices: CANDU, HWR and PWR. These benchmark problems were then used to analyze the root cause of the better performance of the coarse-mesh FDM for CANDU-type reactors. The analyses confirm that the better performance of the coarse-mesh FDM for CANDU-type reactors is mainly caused by the use of lattice-homogenized cross sections for the sub-meshes of the cluster fuel geometry in the diffusion calculation. Based on the analyses, it is recommended to use 2 x 2 coarse-mesh FDM to analyze CANDU-type reactors when lattice-homogenized cross sections are used in the core analysis. (authors)

Root-cause analysis of the better performance of the coarse-mesh finite-difference method for CANDU-type reactors

Energy Technology Data Exchange (ETDEWEB)

Shen, W. [Candu Energy Inc., 2285 Speakman Dr., Mississauga, ON L5B 1K (Canada)

2012-07-01

Recent assessment results indicate that the coarse-mesh finite-difference method (FDM) gives consistently smaller percent differences in channel powers than the fine-mesh FDM when compared to the reference MCNP solution for CANDU-type reactors. However, there is an impression that the fine-mesh FDM should always give more accurate results than the coarse-mesh FDM in theory. To answer the question if the better performance of the coarse-mesh FDM for CANDU-type reactors was just a coincidence (cancellation of errors) or caused by the use of heavy water or the use of lattice-homogenized cross sections for the cluster fuel geometry in the diffusion calculation, three benchmark problems were set up with three different fuel lattices: CANDU, HWR and PWR. These benchmark problems were then used to analyze the root cause of the better performance of the coarse-mesh FDM for CANDU-type reactors. The analyses confirm that the better performance of the coarse-mesh FDM for CANDU-type reactors is mainly caused by the use of lattice-homogenized cross sections for the sub-meshes of the cluster fuel geometry in the diffusion calculation. Based on the analyses, it is recommended to use 2 x 2 coarse-mesh FDM to analyze CANDU-type reactors when lattice-homogenized cross sections are used in the core analysis. (authors)

Properties of Non-Structural Concrete Made with Mixed Recycled Aggregates and Low Cement Content

Science.gov (United States)

López-Uceda, Antonio; Ayuso, Jesús; López, Martin; Jimenez, José Ramón; Agrela, Francisco; Sierra, María José

2016-01-01

In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA) could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i) to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement, on the mechanical and physical properties of a non-structural concrete made with a low cement content; and (ii) to verify if it is possible to achieve a low-strength concrete that replaces a greater amount of natural aggregate with MRA and that has a low cement content. Two series of concrete mixes were manufactured using 180 and 200 kg/m3 of CEM II/A-V 42.5 R type Portland cement. Each series included seven concrete mixes: one with natural aggregates; two MRA with different ceramic particle contents; and one for each coarse aggregate replacement ratio (20%, 40%, and 100%). To study their properties, compressive and splitting tensile strength, modulus of elasticity, density, porosity, water penetration, and sorptivity, tests were performed. The results confirmed that the main factors affecting the properties analyzed in this research are the amount of cement and the replacement ratio; the two MRAs used in this work presented a similar influence on the properties. A non-structural, low-strength concrete (15 MPa) with an MRA replacement ratio of up to 100% for 200 kg/m3 of cement was obtained. This type of concrete could be applied in the construction of ditches, sidewalks, and other similar civil works. PMID:28787874

Vertically-resolved particle size distribution within and above the mixing layer over the Milan metropolitan area

Directory of Open Access Journals (Sweden)

L. Ferrero

2010-04-01

Full Text Available Vertical aerosol profiles were directly measured over the city of Milan during three years (2005–2008 of field campaigns. An optical particle counter, a portable meteorological station and a miniaturized cascade impactor were deployed on a tethered balloon. More than 300 vertical profiles were measured, both in winter and summer, mainly in conditions of clear, dry skies.

The mixing height was determined from the observed vertical aerosol concentration gradient, and from potential temperature and relative humidity profiles. Results show that inter-consistent mixing heights can be retrieved highlighting good correlations between particle dispersion in the atmosphere and meteorological parameters. Mixing height growth speed was calculated for both winter and summer showing the low potential atmospheric dispersion in winter.

Aerosol number size distribution and chemical composition profiles allowed us to investigate particle behaviour along height. Aerosol measurements showed changes in size distribution according to mixing height. Coarse particle profiles (d_p>1.6 μm were distributed differently than the fine ones (d_p<1.6 μm were, at different heights of the mixing layer. The sedimentation process influenced the coarse particle profiles, and led to a reduction in mean particle diameter for those particles observed by comparing data above the mixing height with ground data (−14.9±0.6% in winter and −10.7±1.0% in summer. Conversely, the mean particle diameter of fine particles increased above the mixing height under stable atmospheric conditions; the average increase, observed by comparing data above the mixing height with ground data, was +2.1±0.1% in winter and +3.9±0.3% in summer. A hierarchical statistical model was created to describe the changes in the size distribution of fine particles along height. The proposed model can be used to estimate the typical vertical

Network topology exploration of mesh-based coarse-grain reconfigurable architectures

NARCIS (Netherlands)

Bansal, N.; Gupta, S.; Dutt, N.D.; Nicolau, A.; Gupta, R.

2004-01-01

Several coarse-grain reconfigurable architectures proposed recently consist of a large number of processing elements (PEs) connected in a mesh-like network topology. We study the effects of three aspects of network topology exploration on the performance of applications on these architectures: (a)

Field Performance of Nine Soil Water Content Sensors on a Sandy Loam Soil in New Brunswick, Maritime Region, Canada

Directory of Open Access Journals (Sweden)

Lionel Stevens

2009-11-01

Full Text Available An in situ field test on nine commonly-used soil water sensors was carried out in a sandy loam soil located in the Potato Research Center, Fredericton, NB (Canada using the gravimetric method as a reference. The results showed that among the tested sensors, regardless of installation depths and soil water regimes, CS615, Trase, and Troxler performed the best with the factory calibrations, with a relative root mean square error (RRMSE of 15.78, 16.93, and 17.65%, and a r2 of 0.75, 0.77, and 0.65, respectively. TRIME, Moisture Point (MP917, and Gopher performed slightly worse with the factory calibrations, with a RRMSE of 45.76, 26.57, and 20.41%, and a r2 of 0.65, 0.72, and 0.78, respectively, while the Gypsum, WaterMark, and Netafim showed a frequent need for calibration in the application in this region.

The mechanical behavior of two warm-mix asphalts

Directory of Open Access Journals (Sweden)

H. A. Rondón-Quintana

2016-09-01

Full Text Available This paper presents results stemming from a comparative experimental analysis of two warm-mix asphalts (WMA and a dense-graded hot-mix asphalt (HMA. In order to evaluate asphalt mixture behavior, physical and rheological tests were conducted, including tests on resilient modulus, resistance to moisture-induced damage, resistance to fatigue and resistance to permanent deformation. Samples studied were subjected to short (STOA and long-term (LTOA aging. As far as asphalt mixture composition is concerned, the same particle size distribution and coarse aggregate were employed for both mixture types. The control HMA mixture was produced with AC 60-70, and the WMAs used the same asphalt cement modified with two chemical additives (Rediset WMX® and Cecabase RT®. The modified mixtures exhibited better resistance to permanent deformation, aging and moisture-induced damage (versus the control mixture. Likewise, WMAs generally saw increased fatigue resistance under controlled-stress loading, which rheological characterization showed is mainly attributable to binder additives and their concomitant modifications.

Multilevel Methods for Elliptic Problems with Highly Varying Coefficients on Nonaligned Coarse Grids

Energy Technology Data Exchange (ETDEWEB)

Scheichl, Robert [Univ. of Bath (United Kingdom). Dept. of Mathematical Sciences; Vassilevski, Panayot S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zikatanov, Ludmil T. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mathematics

2012-06-21

We generalize the analysis of classical multigrid and two-level overlapping Schwarz methods for 2nd order elliptic boundary value problems to problems with large discontinuities in the coefficients that are not resolved by the coarse grids or the subdomain partition. The theoretical results provide a recipe for designing hierarchies of standard piecewise linear coarse spaces such that the multigrid convergence rate and the condition number of the Schwarz preconditioned system do not depend on the coefficient variation or on any mesh parameters. One assumption we have to make is that the coarse grids are sufficiently fine in the vicinity of cross points or where regions with large diffusion coefficients are separated by a narrow region where the coefficient is small. We do not need to align them with possible discontinuities in the coefficients. The proofs make use of novel stable splittings based on weighted quasi-interpolants and weighted Poincaré-type inequalities. Finally, numerical experiments are included that illustrate the sharpness of the theoretical bounds and the necessity of the technical assumptions.

Coarse Grained Transport Model for Neutrals in Turbulent SOL Plasmas

Energy Technology Data Exchange (ETDEWEB)

Marandet, Y.; Mekkaoui, A.; Genesio, P.; Rosato, J.; Capes, H.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R., E-mail: yannick.marandet@univ-amu.fr [PIIM, CNRS/Aix-Marseille University, Marseille (France); Reiter, D.; Boerner, P. [IEK4, FZJ, Juelich (Germany)

2012-09-15

Full text: Edge plasmas of magnetic fusion devices exhibit strong intermittent turbulence, which governs perpendicular transport of particles and heat. Turbulent fluxes result from the coarse graining procedure used to derive the transport equation, which entails time averaging of the underlying equations governing the turbulent evolution of the electron and ion fluids. In previous works, we have pointed out that this averaging is not carried out on the Boltzmann equation that describes the transport of neutral particles (atoms, molecules) in current edge code suites (such as SOLPS). Since fluctuations in the far SOL are of order unity, calculating the transport of neutral particles, hence the source terms in plasma fluid equations, in the average plasma background might lead to misleading results. In particular, retaining the effects of fluctuations could affect the estimation of the importance of main chamber recycling, hence first wall sputtering by charge exchange atoms, as well as main chamber impurity contamination and transport. In this contribution, we obtain an exact coarse-grained equation for the average neutral density, assuming that density fluctuations are described by multivariate Gamma statistics. This equation is a scattering free Boltzmann equation, where the ionization rate has been renormalized to account for fluctuations. The coarse grained transport model for neutrals has been implemented in the EIRENE code, and applications in 2D geometry with ITER relevant plasma parameters are presented. Our results open the way for the implementation of the effects of turbulent fluctuations on the transport of neutral particles in coupled plasma/neutral edge codes like B2-EIRENE. (author)

IMPACT OF THE REPEATED TRACTOR PASSES ON SOME PHYSICAL PROPERTIES OF SILTY LOAM SOIL

Directory of Open Access Journals (Sweden)

Dubravko Filipović

2011-12-01

Full Text Available The aim of this paper was to quantify soil compaction induced by tractor traffic on untilled wet silty loam soil (Mollic Fluvisol. Changes in penetration resistance, bulk density and total porosity were measured for detecting the soil compaction. Treatments include ten passes of a four-wheel drive tractor with the engine power of 54.0 kW and weight of 3560 kg (1580 kg on the front axle and 1980 kg on the rear axle, 2.41 m distance between axles. The tyres on the tractor were cross-ply, front 11.2-24 and rear 16.9-30, with the inflation pressure of 160 kPa and 100 kPa, respectively. The speed of tractor during passes over experimental plots was 5.0 km h-1. In comparison to control, each tractor pass induced an increase in soil penetration resistance at all depths, and the average increment ratios, determined as the average of all layers, were 9.8, 18.5 and 26.1% after one, five and ten passes, respectively. The bulk density also increased with number of tractor passes, but with less percentage increasing. The increment ratios comparison to the control were 3.6, 9.5 and 12.9% after one, five and ten passes, respectively. The total porosity decreased with the number of passes, and the decrement ratios were 4.5, 16.5 and 20.8% after one, five and ten passes, respectively.

Comparison of non-parametric methods for ungrouping coarsely aggregated data

DEFF Research Database (Denmark)

Rizzi, Silvia; Thinggaard, Mikael; Engholm, Gerda

2016-01-01

group at the highest ages. When histogram intervals are too coarse, information is lost and comparison between histograms with different boundaries is arduous. In these cases it is useful to estimate detailed distributions from grouped data. Methods From an extensive literature search we identify five...

Improved Parameters for the Martini Coarse-Grained Protein Force Field

NARCIS (Netherlands)

de Jong, Djurre H.; Singh, Gurpreet; Bennett, W. F. Drew; Arnarez, Clement; Wassenaar, Tsjerk A.; Schafer, Lars V.; Periole, Xavier; Tieleman, D. Peter; Marrink, Siewert J.

The Martini coarse-grained force field has been successfully used for simulating a wide range of (bio)molecular systems. Recent progress in our ability to test the model against fully atomistic force fields, however, has revealed some shortcomings. Most notable, phenylalanine and proline were too

Modeling respiration from snags and coarse woody debris before and after an invasive gypsy moth disturbance

Science.gov (United States)

Heidi J. Renninger; Nicholas Carlo; Kenneth L. Clark; Karina V.R. Schäfer

2014-01-01

Although snags and coarse woody debris are a small component of ecosystem respiration, disturbances can significantly increase the mass and respiration from these carbon (C) pools. The objectives of this study were to (1) measure respiration rates of snags and coarse woody debris throughout the year in a forest previously defoliated by gypsy moths, (2) develop models...

Evaluation of coarse scale land surface remote sensing albedo product over rugged terrain

Science.gov (United States)

Wen, J.; Xinwen, L.; You, D.; Dou, B.

2017-12-01

Satellite derived Land surface albedo is an essential climate variable which controls the earth energy budget and it can be used in applications such as climate change, hydrology, and numerical weather prediction. The accuracy and uncertainty of surface albedo products should be evaluated with a reliable reference truth data prior to applications. And more literatures investigated the validation methods about the albedo validation in a flat or homogenous surface. However, the albedo performance over rugged terrain is still unknow due to the validation method limited. A multi-validation strategy is implemented to give a comprehensive albedo validation, which will involve the high resolution albedo processing, high resolution albedo validation based on in situ albedo, and the method to upscale the high resolution albedo to a coarse scale albedo. Among them, the high resolution albedo generation and the upscale method is the core step for the coarse scale albedo validation. In this paper, the high resolution albedo is generated by Angular Bin algorithm. And a albedo upscale method over rugged terrain is developed to obtain the coarse scale albedo truth. The in situ albedo located 40 sites in mountain area are selected globally to validate the high resolution albedo, and then upscaled to the coarse scale albedo by the upscale method. This paper takes MODIS and GLASS albedo product as a example, and the prelimarily results show the RMSE of MODIS and GLASS albedo product over rugged terrain are 0.047 and 0.057, respectively under the RMSE with 0.036 of high resolution albedo.

Effect of acicular ferrite formation on grain refinement in the coarse-grained region of heat-affected zone

International Nuclear Information System (INIS)

Wan, X.L.; Wei, R.; Wu, K.M.

2010-01-01

The microstructure of acicular ferrite and its formation for the grain refinement of coarse-grained region of heat-affected zone of high strength low-alloy bainite steels were studied using three-dimensional reconstruction technique. Crystallographic grain size was analyzed by means of electron backscatter diffraction. It was revealed that the microstructure in the coarse-grained region of the heat-affected zone consisted of predominantly bainite packets and a small proportion of acicular ferrite. Acicular ferrite was of lath or plate-like rather than needle or rod-like morphology. Tempering of the coarse-grained region of heat-affected zone showed that the acicular ferrite was more stable than the bainite, indicating that the acicular ferrite was formed prior to bainite. The acicular ferrite laths or plates divided the prior austenite grains into smaller and separate regions, and confining the bainite transformed at lower temperatures in the smaller regions and hence leading to the grain refinement in the coarse-grained region of the heat-affected zone.

Effect of acicular ferrite formation on grain refinement in the coarse-grained region of heat-affected zone

Energy Technology Data Exchange (ETDEWEB)

Wan, X.L.; Wei, R. [Institute of Advanced Steels and Welding Technology, Hubei Provincial Key Laboratory for Systems Science on Metallurgical Processing, Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); Wu, K.M., E-mail: wukaiming@wust.edu.cn [Institute of Advanced Steels and Welding Technology, Hubei Provincial Key Laboratory for Systems Science on Metallurgical Processing, Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China)

2010-07-15

The microstructure of acicular ferrite and its formation for the grain refinement of coarse-grained region of heat-affected zone of high strength low-alloy bainite steels were studied using three-dimensional reconstruction technique. Crystallographic grain size was analyzed by means of electron backscatter diffraction. It was revealed that the microstructure in the coarse-grained region of the heat-affected zone consisted of predominantly bainite packets and a small proportion of acicular ferrite. Acicular ferrite was of lath or plate-like rather than needle or rod-like morphology. Tempering of the coarse-grained region of heat-affected zone showed that the acicular ferrite was more stable than the bainite, indicating that the acicular ferrite was formed prior to bainite. The acicular ferrite laths or plates divided the prior austenite grains into smaller and separate regions, and confining the bainite transformed at lower temperatures in the smaller regions and hence leading to the grain refinement in the coarse-grained region of the heat-affected zone.

Soil washing results for mixed waste pond soils at Hanford

International Nuclear Information System (INIS)

Gerber, M.A.; Freeman, H.D.; Baker, E.G.; Riemath, W.F.

1991-01-01

Soil washing technology was assessed as a means for remediating soil contaminated with mixed wastes primarily composed of heavy metals and radionuclides. The soils at the US Department of Energy's Hanford Site are considered suitable for soil washing because of their relatively low quantities of silt and clay. However, in a limited number of soil washing experiments using soils from different locations in the north pond of the 300 Area, the degree of decontamination achieved for the coarse fraction of the soil varied considerably. Part of this variation appears to be due to the presence of a discrete layer of contaminated sediment found in some of the samples

Managing coarse woody debris in forests of the Rocky Mountains

Science.gov (United States)

Russell T. Graham; Alan E. Harvey; Martin F. Jurgensen; Theresa B. Jain; Jonalea R. Tonn; Deborah S. Page-Dumroese

1994-01-01

Recommendations for managing coarse woody debris after timber harvest were developed for 14 habitat types, ranging from ponderosa pine (Pinus ponderosa) habitat types of Arizona to subalpine fir (Abies lasiocarpa) habitat types of western Montana. Ectomycorrhizae were used as a bioindicator of healthy, productive forest soils....

Mineral Elements Content of some Coarse Grains used as staple ...

African Journals Online (AJOL)

Analysis of mineral elements were carried out on some coarse grains used as staple food in Kano metropolis. The levels of Magnesium, Calcium, Manganese, Iron, Copper and Zinc were determined using atomic absorption spectrophotometer (AAS), and that of Sodium and Potassium were obtained using flame photometer ...

The influence of land use and management on nitrogen leaching in two agricultural catchments in China and Denmark

DEFF Research Database (Denmark)

Manevski, Kiril

The agriculture in both China and Denmark needs to reduce nitrogen (N) leaching from the crop root zone in order to maintain high-quality groundwater for drinking purposes and to reduce eutrophication of surface waters. However, N leaching is a process that is concurrent and interacting with many...... others in the agro-ecosystem, such as crop growth and N uptake, mineralization of soil organic N and field management practices. Thus, the aim of the Ph.D. study was to investigate, with the use of the physically-based DAISY agro-ecosystem model, crop growth, soil N and leaching processes from (i) maize......-winter wheat annual systems at different fertilizer N rates in the North China Plain (NCP, silty loam soil), China, and (ii) maize for silage systems differing in past cropping, intercropping and fertilizer N levels in central Jutland (sandy loam soil, JB4) and southern Jutland (coarse sandy soil JB1, Jyndevad...

Quantum Mechanics/Molecular Mechanics Method Combined with Hybrid All-Atom and Coarse-Grained Model: Theory and Application on Redox Potential Calculations.

Science.gov (United States)

Shen, Lin; Yang, Weitao

2016-04-12

We developed a new multiresolution method that spans three levels of resolution with quantum mechanical, atomistic molecular mechanical, and coarse-grained models. The resolution-adapted all-atom and coarse-grained water model, in which an all-atom structural description of the entire system is maintained during the simulations, is combined with the ab initio quantum mechanics and molecular mechanics method. We apply this model to calculate the redox potentials of the aqueous ruthenium and iron complexes by using the fractional number of electrons approach and thermodynamic integration simulations. The redox potentials are recovered in excellent accordance with the experimental data. The speed-up of the hybrid all-atom and coarse-grained water model renders it computationally more attractive. The accuracy depends on the hybrid all-atom and coarse-grained water model used in the combined quantum mechanical and molecular mechanical method. We have used another multiresolution model, in which an atomic-level layer of water molecules around redox center is solvated in supramolecular coarse-grained waters for the redox potential calculations. Compared with the experimental data, this alternative multilayer model leads to less accurate results when used with the coarse-grained polarizable MARTINI water or big multipole water model for the coarse-grained layer.

Shape tracking with occlusions via coarse-to-fine region-based sobolev descent

KAUST Repository

Yang, Yanchao

2015-05-01

We present a method to track the shape of an object from video. The method uses a joint shape and appearance model of the object, which is propagated to match shape and radiance in subsequent frames, determining object shape. Self-occlusions and dis-occlusions of the object from camera and object motion pose difficulties to joint shape and appearance models in tracking. They are unable to adapt to new shape and appearance information, leading to inaccurate shape detection. In this work, we model self-occlusions and dis-occlusions in a joint shape and appearance tracking framework. Self-occlusions and the warp to propagate the model are coupled, thus we formulate a joint optimization problem. We derive a coarse-to-fine optimization method, advantageous in tracking, that initially perturbs the model by coarse perturbations before transitioning to finer-scale perturbations seamlessly. This coarse-to-fine behavior is automatically induced by gradient descent on a novel infinite-dimensional Riemannian manifold that we introduce. The manifold consists of planar parameterized regions, and the metric that we introduce is a novel Sobolev metric. Experiments on video exhibiting occlusions/dis-occlusions, complex radiance and background show that occlusion/dis-occlusion modeling leads to superior shape accuracy. © 2014 IEEE.

Mesoscale mixing of the Denmark Strait Overflow in the Irminger Basin

Science.gov (United States)

Koszalka, Inga M.; Haine, Thomas W. N.; Magaldi, Marcello G.

2017-04-01

The Denmark Strait Overflow (DSO) is a major export route for dense waters from the Nordic Seas forming the lower limb of the Atlantic Meridional Overturning Circulation, an important element of the climate system. Mixing processes along the DSO pathway influence its volume transport and properties contributing to the variability of the deep overturning circulation. They are poorly sampled by observations, however, which hinders development of a proper DSO representation in global circulation models. We employ a high resolution regional ocean model of the Irminger Basin to quantify impact of the mesoscale flows on DSO mixing focusing on geographical localization and the time-modulation of water property changes. The model reproduces the observed bulk warming of the DSO plume 100-200 km downstream of the Denmark Strait sill. It also reveals that mesoscale variability of the overflow ('DSO-eddies', of 20-30 km extent and a time scale of 2-5 day) modulates water property changes and turbulent mixing, diagnosed with the vertical shear of horizontal velocity and the eddy heat flux divergence. The space-time localization of the DSO mixing and warming and the role of coherent mesoscale structures should be explored by turbulence measurements and factored into the coarse circulation models.

The basis of orientation decoding in human primary visual cortex: fine- or coarse-scale biases?

Science.gov (United States)

Maloney, Ryan T

2015-01-01

Orientation signals in human primary visual cortex (V1) can be reliably decoded from the multivariate pattern of activity as measured with functional magnetic resonance imaging (fMRI). The precise underlying source of these decoded signals (whether by orientation biases at a fine or coarse scale in cortex) remains a matter of some controversy, however. Freeman and colleagues (J Neurosci 33: 19695-19703, 2013) recently showed that the accuracy of decoding of spiral patterns in V1 can be predicted by a voxel's preferred spatial position (the population receptive field) and its coarse orientation preference, suggesting that coarse-scale biases are sufficient for orientation decoding. Whether they are also necessary for decoding remains an open question, and one with implications for the broader interpretation of multivariate decoding results in fMRI studies. Copyright © 2015 the American Physiological Society.

Nitrogen balances of innovative cropping systems for feedstock production to future biorefineries

DEFF Research Database (Denmark)

Manevski, Kiril; Lærke, Poul Erik; Olesen, Jørgen Eivind

2018-01-01

maize monoculture, the optimised rotation supplied 70% more biomass N and 40% less nitrate leaching on coarse sandy soil, whereas on sandy loam soil it yielded about 10% less biomass N with 50% less nitrate leaching. Field surface N balances were overall neutral/positive, except for festulolium...... and continuous maize monoculture that slightly mined the soil for N. When N losses by leaching, denitrification and volatilisation were included, soil total N stocks were estimated to decline for the majority of the systems at both sites....

The MARTINI force field : Coarse grained model for biomolecular simulations

NARCIS (Netherlands)

Marrink, Siewert J.; Risselada, H. Jelger; Yefimov, Serge; Tieleman, D. Peter; de Vries, Alex H.

2007-01-01

We present an improved and extended version of our coarse grained lipid model. The new version, coined the MARTINI force field, is parametrized in a systematic way, based on the reproduction of partitioning free energies between polar and apolar phases of a large number of chemical compounds. To

Separation of the Stern and diffuse layer in coarse-grained models: the cases of phosphatidyl serine, phosphatidic acid, and PIP2 monolayers.

Science.gov (United States)

Vangaveti, S; Travesset, A

2014-12-28

We present here a method to separate the Stern and diffuse layer in general systems into two regions that can be analyzed separately. The Stern layer can be described in terms of Bjerrum pairing and the diffuse layer in terms of Poisson-Boltzmann theory (monovalent) or strong coupling theory plus a slowly decaying tail (divalent). We consider three anionic phospholipids: phosphatidyl serine, phosphatidic acid, and phosphatidylinositol(4,5)bisphosphate (PIP2), which we describe within a minimal coarse-grained model as a function of ionic concentration. The case of mixed lipid systems is also considered, which shows a high level of binding cooperativity as a function of PIP2 localization. Implications for existing experimental systems of lipid heterogeneities are also discussed.

Coarse woody debris metrics in a California oak woodland

Science.gov (United States)

William D. Tietje; Michael A. Hardy; Christopher C. Yim

2015-01-01

Little information is available on the metrics of coarse woody debris (CWD) in California oak woodland, most notably at the scale of the stand and woodland type. In a remote part of the National Guard Post, Camp Roberts, that has not burned in over a half century, we tallied 314 pieces of CWD in a blue oak (Quercus douglasii)-coast live oak (

Generalized Coarse-Mesh Rebalance Method for Acceleration of Neutron Transport Calculations

International Nuclear Information System (INIS)

Yamamoto, Akio

2005-01-01

This paper proposes a new acceleration method for neutron transport calculations: the generalized coarse-mesh rebalance (GCMR) method. The GCMR method is a unified scheme of the traditional coarse-mesh rebalance (CMR) and the coarse-mesh finite difference (CMFD) acceleration methods. Namely, by using an appropriate acceleration factor, formulation of the GCMR method becomes identical to that of the CMR or CMFD method. This also indicates that the convergence property of the GCMR method can be controlled by the acceleration factor since the convergence properties of the CMR and CMFD methods are generally different. In order to evaluate the convergence property of the GCMR method, a linearized Fourier analysis was carried out for a one-group homogeneous medium, and the results clarified the relationship between the acceleration factor and the spectral radius. It was also shown that the spectral radius of the GCMR method is smaller than those of the CMR and CMFD methods. Furthermore, the Fourier analysis showed that when an appropriate acceleration factor was used, the spectral radius of the GCMR method did not exceed unity in this study, which was in contrast to the results of the CMR or the CMFD method. Application of the GCMR method to practical calculations will be easy when the CMFD acceleration is already adopted in a transport code. By multiplying a suitable acceleration factor to a coefficient (D FD ) of a finite difference formulation, one can improve the numerical instability of the CMFD acceleration method

Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates.

Science.gov (United States)

Siringi, Gideon; Abolmaali, Ali; Aswath, Pranesh B

2015-01-01

Tire derived aggregate (TDA) has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA) and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength) based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA.

Effects of oil palm shell coarse aggregate species on high strength lightweight concrete.

Science.gov (United States)

Yew, Ming Kun; Bin Mahmud, Hilmi; Ang, Bee Chin; Yew, Ming Chian

2014-01-01

The objective of this study was to investigate the effects of different species of oil palm shell (OPS) coarse aggregates on the properties of high strength lightweight concrete (HSLWC). Original and crushed OPS coarse aggregates of different species and age categories were investigated in this study. The research focused on two OPS species (dura and tenera), in which the coarse aggregates were taken from oil palm trees of the following age categories (3-5, 6-9, and 10-15 years old). The results showed that the workability and dry density of the oil palm shell concrete (OPSC) increase with an increase in age category of OPS species. The compressive strength of specimen CD3 increases significantly compared to specimen CT3 by 21.8%. The maximum achievable 28-day and 90-day compressive strength is 54 and 56 MPa, respectively, which is within the range for 10-15-year-old crushed dura OPS. The water absorption was determined to be within the range for good concrete for the different species of OPSC. In addition, the ultrasonic pulse velocity (UPV) results showed that the OPS HSLWC attain good condition at the age of 3 days.

PRODUÇÃO E CONCENTRAÇÃO DE METAIS PESADOS EM PLANTAS DE BETERRABA ADUBADAS COM COMPOSTO DE LIXO URBANO

Directory of Open Access Journals (Sweden)

Regynaldo Arruda Sampaio

2008-01-01

Full Text Available The objective of this work was to evaluate the effect of the urban waste compost on the yield and heavy metals concentrations in red beet plants (Beta vulgaris L. in soils with different textures. The experiment was carried out in greenhouse in polyethylene recipients of 9 dm3. The experimental treatments resulted from a 3 x 4 factorial arrangement of a Red Yellow Latosol, sandy clay loam, (LVAfaa, a Red Yellow Latosol, loamy sand, (LVAfa and a Quartzarenic Neosol, sand loam, (RQ, combined with the urban waste compost doses of 0, 30, 60 and 90 t/ha, in dry base. The experimental design was in randomized blocks with three replications of the treatments. Soil pH, fresh and dry matter weight and Zn, Cu, Cd, Pb and Ni concentrations in the soil and the leaf tissue were determined. Amongst heavy metals determined, Zn and Cu had been only influenced by the soil texture, being biggest concentrations in the soil with bigger amount of clay. The dry and fresh weights of the red beet root had increased with the increment of the doses of compost, having reached maximum values, inside of the experimental interval, with the 90 t.ha-1. Otherwise, the heavy metal content in red beet root decreased with the increase of the doses of compost. As much the Ni how much the Pb had presented content level in root above of the allowed maximum limits for the consumption, as values established for the Brazilian legislation.

An exactly solvable coarse-grained model for species diversity

Science.gov (United States)

Suweis, Samir; Rinaldo, Andrea; Maritan, Amos

2012-07-01

We present novel analytical results concerning ecosystem species diversity that stem from a proposed coarse-grained neutral model based on birth-death processes. The relevance of the problem lies in the urgency for understanding and synthesizing both theoretical results from ecological neutral theory and empirical evidence on species diversity preservation. The neutral model of biodiversity deals with ecosystems at the same trophic level, where per capita vital rates are assumed to be species independent. Closed-form analytical solutions for the neutral theory are obtained within a coarse-grained model, where the only input is the species persistence time distribution. Our results pertain to: the probability distribution function of the number of species in the ecosystem, both in transient and in stationary states; the n-point connected time correlation function; and the survival probability, defined as the distribution of time spans to local extinction for a species randomly sampled from the community. Analytical predictions are also tested on empirical data from an estuarine fish ecosystem. We find that emerging properties of the ecosystem are very robust and do not depend on specific details of the model, with implications for biodiversity and conservation biology.

An exactly solvable coarse-grained model for species diversity

International Nuclear Information System (INIS)

Suweis, Samir; Maritan, Amos; Rinaldo, Andrea

2012-01-01

We present novel analytical results concerning ecosystem species diversity that stem from a proposed coarse-grained neutral model based on birth–death processes. The relevance of the problem lies in the urgency for understanding and synthesizing both theoretical results from ecological neutral theory and empirical evidence on species diversity preservation. The neutral model of biodiversity deals with ecosystems at the same trophic level, where per capita vital rates are assumed to be species independent. Closed-form analytical solutions for the neutral theory are obtained within a coarse-grained model, where the only input is the species persistence time distribution. Our results pertain to: the probability distribution function of the number of species in the ecosystem, both in transient and in stationary states; the n-point connected time correlation function; and the survival probability, defined as the distribution of time spans to local extinction for a species randomly sampled from the community. Analytical predictions are also tested on empirical data from an estuarine fish ecosystem. We find that emerging properties of the ecosystem are very robust and do not depend on specific details of the model, with implications for biodiversity and conservation biology. (paper)

Mixed meson masses with domain-wall valence and staggered sea fermions

International Nuclear Information System (INIS)

Orginos, Kostas; Walker-Loud, Andre

2008-01-01

Mixed action lattice calculations allow for an additive lattice-spacing-dependent mass renormalization of mesons composed of one sea and one valence quark, regardless of the type of fermion discretization methods used in the valence and sea sectors. The value of the mass renormalization depends upon the lattice actions used. This mixed meson mass shift is an important lattice artifact to determine for mixed action calculations; because it modifies the pion mass, it plays a central role in the low-energy dynamics of all hadronic correlation functions. We determine the leading order, O(a 2 ), and next-to-leading order, O(a 2 m π 2 ), additive mass shift of valence-sea mesons for a mixed lattice action with domain-wall valence fermions and rooted staggered sea fermions, relevant to the majority of current large scale mixed action lattice efforts. We find that, on the asqtad-improved coarse MILC lattices, this additive mass shift is well parametrized in lattice units by Δ(am) 2 =0.034(2)-0.06(2)(am π ) 2 , which in physical units, using a=0.125 fm, corresponds to Δ(m) 2 =(291±8 MeV) 2 -0.06(2)m π 2 . In terms of the mixed action effective field theory parameters, the corresponding mass shift is given by a 2 Δ Mix =(316±4 MeV) 2 at leading order plus next-to-leading order corrections including the necessary chiral logarithms for this mixed action calculation, determined in this work. Within the precision of our calculation, one cannot distinguish between the full next-to-leading order effective field theory analysis of this additive mixed meson mass shift and the parametrization given above.

Transport of atrazine and dicamba through silt and loam soils

Science.gov (United States)

Tindall, James A.; Friedel, Michael J.

2016-01-01

The objectives of this research were to determine the role of preferential flow paths in the transport of atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) and dicamba (3-6-dichloro-2-methoxybenzoic acid) through silt and loam soils overlying the High Plains aquifer in Nebraska. In a previous study, 3 of 6 study areas demonstrated high percentages of macropores; those three areas were used in this study for analysis of chemical transport. As a subsequent part of the study, 12 intact soil cores (30-cm diameter by 40-cm height), were excavated sequentially, two from each of the following depths: 0-40cm and 40-80cm. These cores were used to study preferential flow characteristics using dye staining and to determine hydraulic properties. Two undisturbed experimental field plots, each with a 3-m2 surface area, were installed in three study areas in Nebraska. Each was instrumented with suction lysimeters and tensiometers at depths of 10cm to 80cm in 10-cm increments. Additionally, each plot was planted with corn (Zea mays). A neutron probe access tube was installed in each plot to determine soil w ater content at 15-cm intervals. All plots were enclosed w ith a raised frame (of 8-cm height) to prevent surface runoff. All suction lysimeters were purged monthly for three months and were sampled immediately prior to pre-plant herbicide application to obtain background chemical concentrations. Atrazine and dicamba moved rapidly through the soil, but only after a heavy rainfall event, probably owing to the presence of preferential flow paths and lack of microbial degradation in these soil areas. Staining of laboratory cores showed a positive correlation between the percent area stained by depth and the subsequent breakthrough of Br- in the laboratory and leaching of field-applied herbicides owing to large rainfall events. Suction lysimeter samples in the field showed increases in concentrations of herbicides at depths where laboratory data indicated greater

Innovations in the flotation of fine and coarse particles

Science.gov (United States)

Fornasiero, D.; Filippov, L. O.

2017-07-01

Research on the mechanisms of particle-bubble interaction has provided valuable information on how to improve the flotation of fine (100 µm) with novel flotation machines which provide higher collision and attachment efficiencies of fine particles with bubbles and lower detachment of the coarse particles. Also, new grinding methods and technologies have reduced energy consumption in mining and produced better mineral liberation and therefore flotation performance.

The impacts of pyrolysis temperature and feedstock type on biochar properties and the effects of biochar application on the properties of a sandy loam

Science.gov (United States)

Aston, Steve; Doerr, Stefan; Street-Perrott, Alayne

2013-04-01

The production of biochar and its application to soil has the potential to make a significant contribution to climate change mitigation whilst simultaneously improving soil fertility, crop yield and soil water-holding capacity. Biochar is produced from various biomass feedstock materials at varying pyrolysis temperatures, but relatively little is known about how these parameters affect the properties of the resultant biochars and their impact on the properties of the soils to which they are subsequently applied. Salix viminalis, M. giganteus and Picea sitchensis feedstocks were chipped then sieved to 2 - 5 mm, oven dried to constant weight, then pyrolyzed at 350, 500, 600 and 800° C in a nitrogen-purged tube furnace. Biochar yields were measured by weighing the mass of each sample before and after pyrolysis. Biochar hydrophobicity was assessed by using a goniometer to measure water-droplet contact-angles. Cation-exchange-capacity (CEC) was measured using the ammonium acetate method. Biochars were also produced in a rotary kiln from softwood pellets at 400, 500, 600 and 700° C then ground to 0.4 - 1 mm and applied to a sandy loam at a rate of 50 g kg-1. Bulk densities of these soil-biochar mixtures were measured on a tapped, dry, basis. The water-holding-capacity (WHC) of each mixture was measured gravimetrically following saturation and free-draining. The filter paper method was used to assess how pyrolysis temperature influences the effect of biochar application on matric suction. For all feedstocks, large decreases in biochar yield were observed between the pyrolysis temperatures of 350° C and 500° C. For Salix viminalis and M. giganteus feedstocks, subsequent reductions in the yield with increasing pyrolysis temperature were much lower. There were significant differences in hydrophobicity between biochars produced from different biomass and mean biochar hydrophobicity decreased with increasing pyrolysis temperature for all feedstocks. Results for CEC and WHC

Soil-bentonite design mix for slurry cutoff walls used as containment barriers

International Nuclear Information System (INIS)

Rad, N.S.; Bachus, R.C.; Jacobson, B.D.

1995-01-01

In recent years, soil-bentonite slurry cutoff walls have been increasingly used as containment barriers around contaminated soils to impede or, in some cases, nearly eliminate the off-site migration of contaminated ground water or other potentially hazardous liquids. The paper presents the procedures used and the results obtained during an extensive laboratory testing program performed to select varying soil-bentonite slurry mix components for a soil-bentonite slurry cutoff wall constructed around an old landfill at a former oil refinery. The landfill is underlain to varying depths by a coarse granular soils that has been exposed to oil-products. Compatibility of three commercially available bentonite products with the free oil-products and the oil-contaminated ground water found at some locations in the landfill was initially investigated. Based on the test results, one of the bentonite products was selected for use in the soil-bentonite slurry testing program. A clayey soil from a borrow source, potable water from the site, and subsurface soils from the proposed soil-bentonite slurry wall alignment were used to form different soil-bentonite slurry mixes. Slump tests were performed to evaluate the workability of the mixes. Based on the test results, a single mix was selected for further study, including permeability/compatibility testing. The results of the compatibility testing program are presented and discussed in the paper. A specific design mix methodology for evaluating the chemical compatibility of soil-bentonite slurry mixes with permeants is proposed

Multiscale coarse-graining of the protein energy landscape.

Directory of Open Access Journals (Sweden)

Ronald D Hills

2010-06-01

Full Text Available A variety of coarse-grained (CG models exists for simulation of proteins. An outstanding problem is the construction of a CG model with physically accurate conformational energetics rivaling all-atom force fields. In the present work, atomistic simulations of peptide folding and aggregation equilibria are force-matched using multiscale coarse-graining to develop and test a CG interaction potential of general utility for the simulation of proteins of arbitrary sequence. The reduced representation relies on multiple interaction sites to maintain the anisotropic packing and polarity of individual sidechains. CG energy landscapes computed from replica exchange simulations of the folding of Trpzip, Trp-cage and adenylate kinase resemble those of other reduced representations; non-native structures are observed with energies similar to those of the native state. The artifactual stabilization of misfolded states implies that non-native interactions play a deciding role in deviations from ideal funnel-like cooperative folding. The role of surface tension, backbone hydrogen bonding and the smooth pairwise CG landscape is discussed. Ab initio folding aside, the improved treatment of sidechain rotamers results in stability of the native state in constant temperature simulations of Trpzip, Trp-cage, and the open to closed conformational transition of adenylate kinase, illustrating the potential value of the CG force field for simulating protein complexes and transitions between well-defined structural states.

The Effect of Morphological Characteristic of Coarse Aggregates Measured with Fractal Dimension on Asphalt Mixture’s High-Temperature Performance

Directory of Open Access Journals (Sweden)

Hainian Wang

2016-01-01

Full Text Available The morphological properties of coarse aggregates, such as shape, angularity, and surface texture, have a great influence on the mechanical performance of asphalt mixtures. This study aims to investigate the effect of coarse aggregate morphological properties on the high-temperature performance of asphalt mixtures. A modified Los Angeles (LA abrasion test was employed to produce aggregates with various morphological properties by applying abrasion cycles of 0, 200, 400, 600, 800, 1000, and 1200 on crushed angular aggregates. Based on a laboratory-developed Morphology Analysis System for Coarse Aggregates (MASCA, the morphological properties of the coarse aggregate particles were quantified using the index of fractal dimension. The high-temperature performances of the dense-graded asphalt mixture (AC-16, gap-graded stone asphalt mixture (SAC-16, and stone mastic asphalt (SMA-16 mixtures containing aggregates with different fractal dimensions were evaluated through the dynamic stability (DS test and the penetration shear test in laboratory. Good linear correlations between the fractal dimension and high-temperature indexes were obtained for all three types of mixtures. Moreover, the results also indicated that higher coarse aggregate angularity leads to stronger high-temperature shear resistance of asphalt mixtures.

Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates

Science.gov (United States)

Siringi, Gideon; Abolmaali, Ali; Aswath, Pranesh B.

2015-01-01

Tire derived aggregate (TDA) has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA) and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength) based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA. PMID:26161440

Making coarse grained polymer simulations quantitatively predictive for statics and dynamics

Science.gov (United States)

Kremer, Kurt

2010-03-01

By combining input from short simulation runs of rather small systems with all atomistic details together with properly adapted coarse grained models we are able quantitatively predict static and especially dynamical properties of both pure polymer melts of long fully entangled but also of systems with low molecular weight additives. Comparisons to rather different experiments such as diffusion constant measurements or NMR relaxation experiments show a remarkable quantitative agreement without any adjustable parameter. Reintroduction of chemical details into the coarse grained trajectories allows the study of long time trajectories in all atomistic detail providing the opportunity for rather different means of data analysis. References: V. Harmandaris, K. Kremer, Macromolecules, in press (2009) V. Harmandaris et al, Macromolecules, 40, 7026 (2007) B. Hess, S. Leon, N. van der Vegt, K. Kremer, Soft Matter 2, 409 (2006) D. Fritz et al, Soft Matter 5, 4556 (2009)

Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates

Directory of Open Access Journals (Sweden)

Gideon Siringi

2015-01-01

Full Text Available Tire derived aggregate (TDA has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA.

HOW to Identify Butternut Canker and Manage Butternut Trees

Science.gov (United States)

M.E. Ostry; M.E. Mielke; R.L. Anderson

1996-01-01

Butternut (Juglans cinerea), also known as white walnut, commonly grows on rich loamy soils in mixed hardwood forests. It ranges from eastern Canada west to Minnesota and as far south as Arkansas, Alabama, Georgia, Louisiana, and Mississippi (fig. 1). The wood is valued for furniture, paneling, specialty products, and carving. Butternut produces nuts for wildlife and...

A general coarse and fine mesh solution scheme for fluid flow modeling in VHTRS

International Nuclear Information System (INIS)

Clifford, I; Ivanov, K; Avramova, M.

2011-01-01

Coarse mesh Computational Fluid Dynamics (CFD) methods offer several advantages over traditional coarse mesh methods for the safety analysis of helium-cooled graphite-moderated Very High Temperature Reactors (VHTRs). This relatively new approach opens up the possibility for system-wide calculations to be carried out using a consistent set of field equations throughout the calculation, and subsequently the possibility for hybrid coarse/fine mesh or hierarchical multi scale CFD simulations. To date, a consistent methodology for hierarchical multi-scale CFD has not been developed. This paper describes work carried out in the initial development of a multi scale CFD solver intended to be used for the safety analysis of VHTRs. The VHTR is considered on any scale to consist of a homogenized two-phase mixture of fluid and stationary solid material of varying void fraction. A consistent set of conservation equations was selected such that they reduce to the single-phase conservation equations for the case where void fraction is unity. The discretization of the conservation equations uses a new pressure interpolation scheme capable of capturing the discontinuity in pressure across relatively large changes in void fraction. Based on this, a test solver was developed which supports fully unstructured meshes for three-dimensional time-dependent compressible flow problems, including buoyancy effects. For typical VHTR flow phenomena the new solver shows promise as an effective candidate for predicting the flow behavior on multiple scales, as it is capable of modeling both fine mesh single phase flows as well as coarse mesh flows in homogenized regions containing both fluid and solid materials. (author)

A distance limited method for sampling downed coarse woody debris

Science.gov (United States)

Jeffrey H. Gove; Mark J. Ducey; Harry T. Valentine; Michael S. Williams

2012-01-01

A new sampling method for down coarse woody debris is proposed based on limiting the perpendicular distance from individual pieces to a randomly chosen sample point. Two approaches are presented that allow different protocols to be used to determine field measurements; estimators for each protocol are also developed. Both protocols are compared via simulation against...

Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

Science.gov (United States)

Patts, Justin R; Barone, Teresa L

2017-05-01

Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may

Fuel type characterization based on coarse resolution MODIS satellite data

Directory of Open Access Journals (Sweden)

Lanorte A

2007-01-01

Full Text Available Fuel types is one of the most important factors that should be taken into consideration for computing spatial fire hazard and risk and simulating fire growth and intensity across a landscape. In the present study, forest fuel mapping is considered from a remote sensing perspective. The purpose is to delineate forest types by exploring the use of coarse resolution satellite remote sensing MODIS imagery. In order to ascertain how well MODIS data can provide an exhaustive classification of fuel properties a sample area characterized by mixed vegetation covers and complex topography was analysed. The study area is located in the South of Italy. Fieldwork fuel type recognitions, performed before, after and during the acquisition of remote sensing MODIS data, were used as ground-truth dataset to assess the obtained results. The method comprised the following three steps: (I adaptation of Prometheus fuel types for obtaining a standardization system useful for remotely sensed classification of fuel types and properties in the considered Mediterranean ecosystems; (II model construction for the spectral characterization and mapping of fuel types based on two different approach, maximum likelihood (ML classification algorithm and spectral Mixture Analysis (MTMF; (III accuracy assessment for the performance evaluation based on the comparison of MODIS-based results with ground-truth. Results from our analyses showed that the use of remotely sensed MODIS data provided a valuable characterization and mapping of fuel types being that the achieved classification accuracy was higher than 73% for ML classifier and higher than 83% for MTMF.

Soil washing results for mixed waste pond soils at Hanford

International Nuclear Information System (INIS)

Gerber, M.A.

1991-09-01

Soil washing technology was assessed as a means for remediating soil contaminated with mixed wastes primarily composed of heavy metals and radionuclides. The soils at the US Department of Energy's Hanford Site are considered suitable for soil washing because of their relatively low quantities of silt and clay. However, in a limited number of soil washing experiments using soils from different locations in the north pond of the 300 Area, the degree of decontamination achieved for the coarse fraction of the soil varied considerably. Part of this variation appears to be due to the presence of a discrete layer of contaminated sediment found in some of the samples. 7 refs., 2 figs., 4 tabs

Depth distribution of preferential flow patterns in a sandy loam soil as affected by tillage

Directory of Open Access Journals (Sweden)

C. T. Petersen

1997-01-01

Full Text Available Dye-tracer studies using the anionic dye Brilliant Blue FCF were conducted on a structured sandy loam soil (Typic Agrudalf. 25 mm of dye solution was applied to the surface of 11 1.6 x 1.6 m field plots, some of which had been subjected to conventional seed bed preparation (harrowing while others had been rotovated to either 5 or 15 cm depth before sowing. The soil was excavated to about 160 cm depth one or two days after dye application. Flow patterns and structural features appearing on vertical or horizontal cross sections were examined and photographed. The flow patterns were digitized, and depth functions for the number of activated flow pathways and the degree of dye coverage were calculated. Dye was found below 100 cm depth on 26 out of 33 vertical cross sections made in conventionally tilled plots showing that preferential flow was a prevailing phenomenon. The depth-averaged number of stained flow pathways in the 25-100 cm layer was significantly smaller in a plot rotovated to 5 cm depth than in a conventionally tilled plot, both under relatively dry initial soil conditions and when the entire soil profiles were initially at field capacity. There were no examples of dye penetration below 25 cm depth one month after deep rotovation. Distinct horizontal structures in flow patterns appearing at 20-40 cm depth coupled with changes in flow domains indicated soil layering with abrupt changes in soil structure and hydraulic properties.

The influence of kind of coating additive on the compressive strength of RCA-based concrete prepared by triple-mixing method

Science.gov (United States)

Urban, K.; Sicakova, A.

2017-10-01

The paper deals with the use of alternative powder additives (fly ash and fine fraction of recycled concrete) to improve the recycled concrete aggregate and this occurs directly in the concrete mixing process. Specific mixing process (triple mixing method) is applied as it is favourable for this goal. Results of compressive strength after 2 and 28 days of hardening are given. Generally, using powder additives for coating the coarse recycled concrete aggregate in the first stage of triple mixing resulted in decrease of compressive strength, comparing the cement. There is no very important difference between samples based on recycled concrete aggregate and those based on natural aggregate as far as the cement is used for coating. When using both the fly ash and recycled concrete powder, the kind of aggregate causes more significant differences in compressive strength, with the values of those based on the recycled concrete aggregate being worse.

Implementing Non Power-of-Two FFTs on Coarse-Grain Reconfigurable Architectures

NARCIS (Netherlands)

Rivaton, Arnaud; Quevremont, Jérôme; Zhang, Q.; Wolkotte, P.T.; Smit, Gerardus Johannes Maria; Nurmi, J.; Takala, J.; Hamalainen, T.D.

2005-01-01

To improve power figures of a dual ARM9 RISC core architecture targeting low-power digital broadcasting applications, the addition of a coarse-grain architecture is considered. This paper introduces two of these structures: PACT's XPP technology and the Montium, developed by the University of

Properties of Arboreal Ant and Ground-Termite Nests in relation to Their Nesting Sites and Location in a Tropical-Derived Savanna

Directory of Open Access Journals (Sweden)

B. C. Echezona

2012-01-01

Full Text Available Ecosystem engineers such as ants and termites play an important role in the fertility of tropical soils. Physicochemical analyses were thus carried out on some arboreal ant nests collected from mango (Mangifera indica, bush mango (Irvingia gabonensis, kola (Cola nitida, newbouldia plant (Newbouldia laevis, and oil bean plant (Pentaclethra macrophylla and on ground nest of termite, Odontotermes sudanensis Sjost. (Isoptera: Termitidae in Nigeria. Arboreal nests, particularly those of M. indica, were significantly richer in the chemical constituents sampled, compared to those of ground-termite nests or adjacent unaffected soils. Available water capacity of nests from M. indica (60.0% was significantly higher than those of other sites or locations sampled. While biogenic structures were sandy-loamy in texture, their corresponding adjacent soils were either sandy or sandy-loamy. Soils worked by ants and termites had greater proportions of silt-sized (17.9 versus 9.7 and clay-sized (19.2 versus 9.3 to the detriment of coarse-sized particles (51.2 versus 60.9 and fine-sand-sized particles (11.7 versus 20.1 relative to the adjacent soils. Generally, biogenic structures were about 348% richer in P than their corresponding adjacent soils; an attribute, which holds a strong promise in bioremediation and biofortification of soils especially during amendment.

A new technique for online measurement of total and water-soluble copper (Cu) in coarse particulate matter (PM)

International Nuclear Information System (INIS)

Wang, Dongbin; Shafer, Martin M.; Schauer, James J.; Sioutas, Constantinos

2015-01-01

This study presents a novel system for online, field measurement of copper (Cu) in ambient coarse (2.5–10 μm) particulate matter (PM). This new system utilizes two virtual impactors combined with a modified liquid impinger (BioSampler) to collect coarse PM directly as concentrated slurry samples. The total and water-soluble Cu concentrations are subsequently measured by a copper Ion Selective Electrode (ISE). Laboratory evaluation results indicated excellent collection efficiency (over 85%) for particles in the coarse PM size ranges. In the field evaluations, very good agreements for both total and water-soluble Cu concentrations were obtained between online ISE-based monitor measurements and those analyzed by means of inductively coupled plasma mass spectrometry (ICP-MS). Moreover, the field tests indicated that the Cu monitor could achieve near-continuous operation for at least 6 consecutive days (a time resolution of 2–4 h) without obvious shortcomings. - Highlights: • A novel only PM sampling and Cu measuring technology is developed. • Very good particle collection efficiency for coarse PM is observed. • Excellent agreement is obtained between Cu ISE and offline ICP-MS measurements. • The new system can be continuously operated for at least 6 consecutive days. - A new technique for online measurements of Cu in coarse PM is described

Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Will Detmold, William Detmold, Konstantinos Orginos, Aaron Torok, Silas R Beane, Thomas C Luu, Assumpta Parreno, Martin Savage, Andre Walker-Loud

2010-04-01

The $\\pi^+\\Sigma^+$, $\\pi^+\\Xi^0$ , $K^+p$, $K^+n$, and $K^0 \\Xi^0$ scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find $a_{\\pi^+\\Sigma^+} = ?0.197 ± 0.017$ fm, and $a_{\\pi^+\\Xi^0} = ?0.098 0.017$ fm, where the comprehensive error includes statistical and systematic uncertainties.

Empirical Models for Power and Energy Requirements II : A Powered Implement Operation in Serdang Sandy Clay Loam, Malaysia

Directory of Open Access Journals (Sweden)

A. F. Kheiralla

2017-12-01

Full Text Available Power and energy requirements were measured with an instrumented tractor for rotary tilling in Serdang sandy clay loam soil.  The effects of travel speed and rotor speed upon the measured data were investigated.  Power model from orthogonal regression analysis was formulated based on linear and quadratic functions of travel speed and bite length.  Fuel consumption model from regression analysis was formulated based on linear tractor PTO power as well as linear equivalent tractor PTO power.  Fuel consumption rates predicted by ASAE D497.3 were found to be 25% to 28% overestimates of the values predicted by the model developed.  However, fuel consumption rates reported by OECD Tractor Test were found to be 1% to 9% lower than the fuel consumption rates predicted by the model developed.  A comparison of power and energy requirements for both powered and draught implements showed that the disk harrow was the most energy efficient implement in terms of fuel consumption and specific energy followed by the rotary tiller, disk plough and mouldboard.  Finally, average PTO power, fuel consumption, wheel slip, wheel power and specific energy for a powered implement are presented.

Flow structure of coarse-grained slurry in a horizontal pipe

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Kysela, Bohuš; Chára, Zdeněk

2012-01-01

Roč. 60, č. 2 (2012), s. 115-124 ISSN 0042-790X R&D Projects: GA ČR GAP105/10/1574 Institutional research plan: CEZ:AV0Z20600510 Keywords : coarse-grained slurry * turbulent flow * pressure drop * velocity distribution * flow structure * concentration effect Subject RIV: BK - Fluid Dynamics Impact factor: 0.653, year: 2012

Effects of Oil Palm Shell Coarse Aggregate Species on High Strength Lightweight Concrete

Directory of Open Access Journals (Sweden)

Ming Kun Yew

2014-01-01

Full Text Available The objective of this study was to investigate the effects of different species of oil palm shell (OPS coarse aggregates on the properties of high strength lightweight concrete (HSLWC. Original and crushed OPS coarse aggregates of different species and age categories were investigated in this study. The research focused on two OPS species (dura and tenera, in which the coarse aggregates were taken from oil palm trees of the following age categories (3–5, 6–9, and 10–15 years old. The results showed that the workability and dry density of the oil palm shell concrete (OPSC increase with an increase in age category of OPS species. The compressive strength of specimen CD3 increases significantly compared to specimen CT3 by 21.8%. The maximum achievable 28-day and 90-day compressive strength is 54 and 56 MPa, respectively, which is within the range for 10–15-year-old crushed dura OPS. The water absorption was determined to be within the range for good concrete for the different species of OPSC. In addition, the ultrasonic pulse velocity (UPV results showed that the OPS HSLWC attain good condition at the age of 3 days.

Quartz luminescence response to a mixed alpha-beta field: Investigations on Romanian loess

DEFF Research Database (Denmark)

Constantin, Daniela; Jain, Mayank; Murray, Andrew S.

2015-01-01

-OSL laboratory dose response curves do not reflect the growth of the OSL signal in nature. A main difference in coarse- and fine-grained quartz dating lies in the alpha irradiation history, but the effect of mixed alpha-beta fields has so far received little attention. In the present study we investigate whether...... the alpha dose experienced by fine grains over geological cycles of irradiation and bleaching may have an effect on the saturation characteristics of the laboratory dose response. By applying time resolved optically stimulated luminescence we confirm that the OSL signals induced in quartz by alpha and beta...

Comparing non-parametric methods for ungrouping coarsely aggregated age-specific distributions

DEFF Research Database (Denmark)

Rizzi, Silvia; Thinggaard, Mikael; Vaupel, James W.

2016-01-01

Demographers have often access to vital statistics that are less than ideal for the purpose of their research. In many instances demographic data are reported in coarse histograms, where the values given are only the summation of true latent values, thereby making detailed analysis troublesome. O...

Multiblob coarse-graining for mixtures of long polymers and soft colloids

Science.gov (United States)

Locatelli, Emanuele; Capone, Barbara; Likos, Christos N.

2016-11-01

Soft nanocomposites represent both a theoretical and an experimental challenge due to the high number of the microscopic constituents that strongly influence the behaviour of the systems. An effective theoretical description of such systems invokes a reduction of the degrees of freedom to be analysed, hence requiring the introduction of an efficient, quantitative, coarse-grained description. We here report on a novel coarse graining approach based on a set of transferable potentials that quantitatively reproduces properties of mixtures of linear and star-shaped homopolymeric nanocomposites. By renormalizing groups of monomers into a single effective potential between a f-functional star polymer and an homopolymer of length N0, and through a scaling argument, it will be shown how a substantial reduction of the to degrees of freedom allows for a full quantitative description of the system. Our methodology is tested upon full monomer simulations for systems of different molecular weight, proving its full predictive potential.

Chemical composition of free tropospheric aerosol for PM1 and coarse mode at the high alpine site Jungfraujoch

Directory of Open Access Journals (Sweden)

J. Cozic

2008-01-01

Full Text Available The chemical composition of submicron (fine mode and supermicron (coarse mode aerosol particles has been investigated at the Jungfraujoch high alpine research station (3580 m a.s.l., Switzerland as part of the GAW aerosol monitoring program since 1999. A clear seasonality was observed for all major components throughout the period with low concentrations in winter (predominantly free tropospheric aerosol and higher concentrations in summer (enhanced vertical transport of boundary layer pollutants. In addition, mass closure was attempted during intensive campaigns in March 2004, February–March 2005 and August 2005. Ionic, carbonaceous and non-refractory components of the aerosol were quantified as well as the PM1 and coarse mode total aerosol mass concentrations. A relatively low conversion factor of 1.8 for organic carbon (OC to particulate organic matter (OM was found in winter (February–March 2005. Organics, sulfate, ammonium, and nitrate were the major components of the fine aerosol fraction that were identified, while calcium and nitrate were the only two measured components contributing to the coarse mode. The aerosol mass concentrations for fine and coarse mode aerosol measured during the intensive campaigns were not typical of the long-term seasonality due largely to dynamical differences. Average fine and coarse mode concentrations during the intensive field campaigns were 1.7 μg m⁻³ and 2.4 μg m⁻³ in winter and 2.5 μg m⁻³ and 2.0 μg m⁻³ in summer, respectively. The mass balance of aerosols showed higher contributions of calcium and nitrate in the coarse mode during Saharan dust events (SDE than without SDE.

Influence of canopy closure and shrub coverage on travel along coarse woody debris by Eastern chipmunks (Tamias striatus)

Science.gov (United States)

Patrick A. Zollner; Kevin J. Crane

2003-01-01

We investigated relationships between canopy closure, shrub cover and the use of coarse woody debris as a travel path by eastern chipmunks (Tamias striatus) in the north central United States. Fine scale movements of chipmunks were followed with tracking spools and the percentage of each movement path directly along coarse woody debris was recorded...

MISTICA: Minimum Spanning Tree-Based Coarse Image Alignment for Microscopy Image Sequences.

Science.gov (United States)

Ray, Nilanjan; McArdle, Sara; Ley, Klaus; Acton, Scott T

2016-11-01

Registration of an in vivo microscopy image sequence is necessary in many significant studies, including studies of atherosclerosis in large arteries and the heart. Significant cardiac and respiratory motion of the living subject, occasional spells of focal plane changes, drift in the field of view, and long image sequences are the principal roadblocks. The first step in such a registration process is the removal of translational and rotational motion. Next, a deformable registration can be performed. The focus of our study here is to remove the translation and/or rigid body motion that we refer to here as coarse alignment. The existing techniques for coarse alignment are unable to accommodate long sequences often consisting of periods of poor quality images (as quantified by a suitable perceptual measure). Many existing methods require the user to select an anchor image to which other images are registered. We propose a novel method for coarse image sequence alignment based on minimum weighted spanning trees (MISTICA) that overcomes these difficulties. The principal idea behind MISTICA is to reorder the images in shorter sequences, to demote nonconforming or poor quality images in the registration process, and to mitigate the error propagation. The anchor image is selected automatically making MISTICA completely automated. MISTICA is computationally efficient. It has a single tuning parameter that determines graph width, which can also be eliminated by the way of additional computation. MISTICA outperforms existing alignment methods when applied to microscopy image sequences of mouse arteries.

Cyclic Behavior of Low Rise Concrete Shear Walls Containing Recycled Coarse and Fine Aggregates.

Science.gov (United States)

Qiao, Qiyun; Cao, Wanlin; Qian, Zhiwei; Li, Xiangyu; Zhang, Wenwen; Liu, Wenchao

2017-12-07

In this study, the cyclic behaviors of low rise concrete shear walls using recycled coarse or fine aggregates were investigated. Eight low rise Recycled Aggregates Concrete (RAC) shear wall specimens were designed and tested under a cyclic loading. The following parameters were varied: replacement percentages of recycled coarse or fine aggregates, reinforcement ratio, axial force ratio and X-shaped rebars brace. The failure characteristics, hysteretic behavior, strength and deformation capacity, strain characteristics and stiffness were studied. Test results showed that the using of the Recycled Coarse Aggregates (RCA) and its replacement ratio had almost no influence on the mechanical behavior of the shear wall; however, the using of Recycled Fine Aggregates (RFA) had a certain influence on the ductility of the shear wall. When the reinforcement ratio increased, the strength and ductility also increased. By increasing the axial force ratio, the strength increased but the ductility decreased significantly. The encased brace had a significant effect on enhancing the RAC shear walls. The experimental maximum strengths were evaluated with existing design codes, it was indicated that the strength evaluation of the low rise RAC shear walls can follow the existing design codes of the conventional concrete shear walls.

Enhancement of physical and hydrological properties of a sandy loam soil via application of different biochar particle sizes during incubation period

Directory of Open Access Journals (Sweden)

Leila Esmaeelnejad

2016-06-01

Full Text Available In spite of many studies that have been carried out, there is a knowledge-gap as to how different sizes of biochars alter soil properties. Therefore, the main objective of this study was to investigate the effects of different sizes of biochars on soil properties. The biochars were produced at two pyrolysis temperatures (350 and 550°C from two feedstocks (rice husk and apple wood chips. Produced biochars were prepared at two diameters (1-2 mm and <1 mm and mixed with soil at a rate of 2% (w/w. Multiple effects of type, temperature and size of biochars were significant, so as the mixture of soil and finer woodchip biochars produced at 550°C had significant effects on all soil properties. Soil aggregation and stabilization of macro-aggregates, values of mean weight diameter and water stable aggregates were improved due to increased soil organic matter as binding agents and microbial biomass. In addition, plant available water capacity, air capacity, S-index, meso-pores and water retention content were significantly increased compared to control. But, saturated hydraulic conductivity (Ks was reduced due to blockage of pores by biochar particles, reduction of pore throat size and available space for flow and also, high field capacity of biochars. So, application of biochar to soil, especially the finest particles of high-tempered woody biochars, can improve physical and hydrological properties of coarse-textured soils and reduce their water drainage by modification of Ks.

Enhancement of physical and hydrological properties of a sandy loam soil via application of different biochar particle sizes during incubation period

Energy Technology Data Exchange (ETDEWEB)

Esmaeelnejad, L.; Shorafa, M.; Gorji, M.; Hosseini, S.M.

2016-11-01

In spite of many studies that have been carried out, there is a knowledge-gap as to how different sizes of biochars alter soil properties. Therefore, the main objective of this study was to investigate the effects of different sizes of biochars on soil properties. The biochars were produced at two pyrolysis temperatures (350 and 550°C) from two feedstocks (rice husk and apple wood chips). Produced biochars were prepared at two diameters (1-2 mm and <1 mm) and mixed with soil at a rate of 2% (w/w). Multiple effects of type, temperature and size of biochars were significant, so as the mixture of soil and finer woodchip biochars produced at 550°C had significant effects on all soil properties. Soil aggregation and stabilization of macro-aggregates, values of mean weight diameter and water stable aggregates were improved due to increased soil organic matter as binding agents and microbial biomass. In addition, plant available water capacity, air capacity, S-index, meso-pores and water retention content were significantly increased compared to control. But, saturated hydraulic conductivity (Ks) was reduced due to blockage of pores by biochar particles, reduction of pore throat size and available space for flow and also, high field capacity of biochars. So, application of biochar to soil, especially the finest particles of high-tempered woody biochars, can improve physical and hydrological properties of coarse-textured soils and reduce their water drainage by modification of Ks. (Author)

Vertical transfer of radionuclides in soils of different genesis after Chernobyl NPP accident

International Nuclear Information System (INIS)

Bakarykava, Zh.; Shagalova, E.; Zhukova, O.

2003-01-01

In this paper a vertical transfer of radionuclides in soils of different genesis after Chernobyl NPP accident was studied. Analysis of obtained data revealed that the main content of cesium-137 is located in 0-5 cm layer of turf-podsolic, sandy-loam and loamy soil provided the lack of their humidification, and of light un-bogged (automorphous) soil as well. Cesium-137 penetration into light un-bogged soils with that sings of surplus humidification is approximately 10 cm deep. Strontium-90 as global birth so Chernobyl origin migrates more rapidly than cesium-137 because of less strong bond with soil absorbing complex. Cesium-137 migration coefficients amounted (0.03-0.46)·10 -7 cm 2 /s for a slow component, and for the fast one (0.39-0.67)·10 -7 cm 2 /s. Strontium-90 migration coefficients in the experimented sites, amounted (0.07-0.58)·10 -7 cm 2 /s for a slow component, and for the fast one (0.64-1.28)·10 -7 cm 2 /s. (authors)

Weed infestation of field crops in different soils in the protective zone of Roztocze National Park. Part II. Root crops

Directory of Open Access Journals (Sweden)

Marta Ziemińska-Smyk

2013-12-01

Full Text Available The study on weed infestation of root crops in different soils in the protective zone of Roztocze National Park was conducted in the years 1991-1995. As many as 240 phytosociological records, made with the use of Braun-Blanquet method, were taken in potato and sugar beet fields. The number of weed species in sugar beet and potato in the area depended on the soil and type of root crop. In the same environment conditions. the iiuinber of weed species was higher in potato than in sugar beet. The most difficult weed species iii all types of soil were: Chenopodium album, Stellaria media and Convolvulus arvensis. Podsolic soils were highly infested by two acidophylic species: Spergula arvensis and Raphanus raphanistum. Potato in loess soil and brown soil made of loamy sands were highly infested by Echinochloa crus-galli, Equisetum arvense and Galinsoga parviflora. Root crop plantations in brown soils formed from gaizes of granulometric loam texture and limestone soils were infested by: Galium aparine, Sonchus arvensis, Sinapis arvensis and Veronica persica.

Spatial and temporal variability of soil moisture in a restored reach of an Alpine river

Science.gov (United States)

Luster, Jörg

2010-05-01

In order to assess the effects of river restoration on water quality, the biogeochemical functions of restored river reaches have to be quantified, and soil moisture is a key environmental variable controlling this functionality. Restored sections of rivers often are characterized by a dynamic mosaic of riparian zones with varying exposure to flooding. In this presentation, the spatial and temporal variability of soil moisture in riparian soils of a restored reach of the Alpine river Thur in northeastern Switzerland is shown. The study was part of the interdisciplinary project cluster RECORD, which was initiated to advance the mechanistic understanding of coupled hydrological and ecological processes in river corridors. The studied river reach comprised the following three functional processing zones (FPZ) representing a lateral successional gradient with decreasing hydrological connectivity (i.e. decreasing flooding frequency and duration). (i) The grass zone developed naturally on a gravel bar after restoration of the channelized river section (mainly colonized by canary reed grass Phalaris arundinacae). The soil is loamy sand to sandy loam composed of up to 80 cm thick fresh sediments trapped and stabilized by the grass roots. (ii) The bush zone is composed of young willow trees (Salix viminalis) planted during restoration to stabilize older overbank deposits with a loamy fine earth. (iii) The mixed forest is a mature riparian hardwood forest with ash and maple as dominant trees developed on older overbank sediments with a silty loamy fine earth. The study period was between spring 2009 and winter 2009/2010 including three flood events in June, July and December 2009. The first and third flood inundated the grass zone and lower part of the bush zone while the second flood was bigger and swept through all the FPZs. Water contents in several soil depths were measured continuously in 30 minute intervals using Decagon EC-5 and EC-TM sensors. There were six spatial

Effects of Particle Size on the Shear Behavior of Coarse Grained Soils Reinforced with Geogrid.

Science.gov (United States)

Kim, Daehyeon; Ha, Sungwoo

2014-02-07

In order to design civil structures that are supported by soils, the shear strength parameters of soils are required. Due to the large particle size of coarse-grained soils, large direct shear tests should be performed. In this study, large direct shear tests on three types of coarse grained soils (4.5 mm, 7.9 mm, and 15.9 mm) were performed to evaluate the effects of particle size on the shear behavior of coarse grained soils with/without geogrid reinforcements. Based on the direct shear test results, it was found that, in the case of no-reinforcement, the larger the maximum particle size became, the larger the friction angle was. Compared with the no-reinforcement case, the cases reinforced with either soft geogrid or stiff geogrid have smaller friction angles. The cohesion of the soil reinforced with stiff geogrid was larger than that of the soil reinforced with soft geogrid. The difference in the shear strength occurs because the case with a stiff geogrid has more soil to geogrid contact area, leading to the reduction in interlocking between soil particles.

Analytical reconstruction schemes for coarse-mesh spectral nodal solution of slab-geometry SN transport problems

International Nuclear Information System (INIS)

Barros, R. C.; Filho, H. A.; Platt, G. M.; Oliveira, F. B. S.; Militao, D. S.

2009-01-01

Coarse-mesh numerical methods are very efficient in the sense that they generate accurate results in short computational time, as the number of floating point operations generally decrease, as a result of the reduced number of mesh points. On the other hand, they generate numerical solutions that do not give detailed information on the problem solution profile, as the grid points can be located considerably away from each other. In this paper we describe two analytical reconstruction schemes for the coarse-mesh solution generated by the spectral nodal method for neutral particle discrete ordinates (S N ) transport model in slab geometry. The first scheme we describe is based on the analytical reconstruction of the coarse-mesh solution within each discretization cell of the spatial grid set up on the slab. The second scheme is based on the angular reconstruction of the discrete ordinates solution between two contiguous ordinates of the angular quadrature set used in the S N model. Numerical results are given so we can illustrate the accuracy of the two reconstruction schemes, as described in this paper. (authors)

Coarse-coded higher-order neural networks for PSRI object recognition. [position, scale, and rotation invariant

Science.gov (United States)

Spirkovska, Lilly; Reid, Max B.

1993-01-01

A higher-order neural network (HONN) can be designed to be invariant to changes in scale, translation, and inplane rotation. Invariances are built directly into the architecture of a HONN and do not need to be learned. Consequently, fewer training passes and a smaller training set are required to learn to distinguish between objects. The size of the input field is limited, however, because of the memory required for the large number of interconnections in a fully connected HONN. By coarse coding the input image, the input field size can be increased to allow the larger input scenes required for practical object recognition problems. We describe a coarse coding technique and present simulation results illustrating its usefulness and its limitations. Our simulations show that a third-order neural network can be trained to distinguish between two objects in a 4096 x 4096 pixel input field independent of transformations in translation, in-plane rotation, and scale in less than ten passes through the training set. Furthermore, we empirically determine the limits of the coarse coding technique in the object recognition domain.

Folding 19 proteins to their native state and stability of large proteins from a coarse-grained model.

Science.gov (United States)

Kapoor, Abhijeet; Travesset, Alex

2014-03-01

We develop an intermediate resolution model, where the backbone is modeled with atomic resolution but the side chain with a single bead, by extending our previous model (Proteins (2013) DOI: 10.1002/prot.24269) to properly include proline, preproline residues and backbone rigidity. Starting from random configurations, the model properly folds 19 proteins (including a mutant 2A3D sequence) into native states containing β sheet, α helix, and mixed α/β. As a further test, the stability of H-RAS (a 169 residue protein, critical in many signaling pathways) is investigated: The protein is stable, with excellent agreement with experimental B-factors. Despite that proteins containing only α helices fold to their native state at lower backbone rigidity, and other limitations, which we discuss thoroughly, the model provides a reliable description of the dynamics as compared with all atom simulations, but does not constrain secondary structures as it is typically the case in more coarse-grained models. Further implications are described. Copyright © 2013 Wiley Periodicals, Inc.

Experimental study on the strength parameter of Quarry Dust mixed Coconut Shell Concrete adding Coconut Fibre

Science.gov (United States)

Matangulu Shrestha, Victor; Anandh, S.; Sindhu Nachiar, S.

2017-07-01

Concrete is a heterogeneous mixture constitute of cement as the main ingredient with a different mix of fine and coarse aggregate. The massive use of conventional concrete has a shortfall in its key ingredients, natural sand and coarse aggregate, due to increased industrialisation and globalisation. To overcome the shortage of material, an alternate material with similar mechanical properties and composition has to be studied, as replacement of conventional concrete. Coconut shell concrete is a prime option as replacement of key ingredients of conventional concrete as coconut is produced in massive quantity in south East Asia. Coconut shell concrete is lightweight concrete and different research is still ongoing concerning about its mix design and composition in the construction industry. Concrete is weak in tension as compared to compression, hence the fibre is used to refrain the crack in the concrete. Coconut fibre is one of many fibres which can be used in concrete. The main aim of this project is to analyse the use of natural by-products in the construction industry, make light weight concrete and eco-friendly construction. This project concerns with the comparison of the mechanical properties of coconut shell concrete and conventional concrete, replacing fine aggregate with quarry dust using coconut fibre. M25 grade of concrete was adopted and testing of concrete was done at the age of 3, 7 and 28 days. In this concrete mix, sand was replaced completely in volumetric measurement by quarry dust. The result was analysed and compared with addition of coconut fibre at varying percentage of 1%, 2%, 3%, 4% and 5%. From the test conducted, coconut shell concrete with quarry dust has the maximum value at 4% of coconut fibre while conventional concrete showed the maximum value at 2% of coconut fibre.

Systematic hierarchical coarse-graining with the inverse Monte Carlo method

Energy Technology Data Exchange (ETDEWEB)

Lyubartsev, Alexander P., E-mail: alexander.lyubartsev@mmk.su.se [Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, S 106 91 Stockholm (Sweden); Naômé, Aymeric, E-mail: aymeric.naome@unamur.be [Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, S 106 91 Stockholm (Sweden); UCPTS Division, University of Namur, 61 Rue de Bruxelles, B 5000 Namur (Belgium); Vercauteren, Daniel P., E-mail: daniel.vercauteren@unamur.be [UCPTS Division, University of Namur, 61 Rue de Bruxelles, B 5000 Namur (Belgium); Laaksonen, Aatto, E-mail: aatto@mmk.su.se [Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, S 106 91 Stockholm (Sweden); Science for Life Laboratory, 17121 Solna (Sweden)

2015-12-28

We outline our coarse-graining strategy for linking micro- and mesoscales of soft matter and biological systems. The method is based on effective pairwise interaction potentials obtained in detailed ab initio or classical atomistic Molecular Dynamics (MD) simulations, which can be used in simulations at less accurate level after scaling up the size. The effective potentials are obtained by applying the inverse Monte Carlo (IMC) method [A. P. Lyubartsev and A. Laaksonen, Phys. Rev. E 52(4), 3730–3737 (1995)] on a chosen subset of degrees of freedom described in terms of radial distribution functions. An in-house software package MagiC is developed to obtain the effective potentials for arbitrary molecular systems. In this work we compute effective potentials to model DNA-protein interactions (bacterial LiaR regulator bound to a 26 base pairs DNA fragment) at physiological salt concentration at a coarse-grained (CG) level. Normally the IMC CG pair-potentials are used directly as look-up tables but here we have fitted them to five Gaussians and a repulsive wall. Results show stable association between DNA and the model protein as well as similar position fluctuation profile.

A coarse-mesh nodal method-diffusive-mesh finite difference method

International Nuclear Information System (INIS)

Joo, H.; Nichols, W.R.

1994-01-01

Modern nodal methods have been successfully used for conventional light water reactor core analyses where the homogenized, node average cross sections (XSs) and the flux discontinuity factors (DFs) based on equivalence theory can reliably predict core behavior. For other types of cores and other geometries characterized by tightly-coupled, heterogeneous core configurations, the intranodal flux shapes obtained from a homogenized nodal problem may not accurately portray steep flux gradients near fuel assembly interfaces or various reactivity control elements. This may require extreme values of DFs (either very large, very small, or even negative) to achieve a desired solution accuracy. Extreme values of DFs, however, can disrupt the convergence of the iterative methods used to solve for the node average fluxes, and can lead to a difficulty in interpolating adjacent DF values. Several attempts to remedy the problem have been made, but nothing has been satisfactory. A new coarse-mesh nodal scheme called the Diffusive-Mesh Finite Difference (DMFD) technique, as contrasted with the coarse-mesh finite difference (CMFD) technique, has been developed to resolve this problem. This new technique and the development of a few-group, multidimensional kinetics computer program are described in this paper

Culturable bioaerosols along an urban waterfront are primarily associated with coarse particles

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Angel Montero

2016-12-01

Full Text Available The source, characteristics and transport of viable microbial aerosols in urban centers are topics of significant environmental and public health concern. Recent studies have identified adjacent waterways, and especially polluted waterways, as an important source of microbial aerosols to urban air. The size of these aerosols influences how far they travel, their resistance to environmental stress, and their inhalation potential. In this study, we utilize a cascade impactor and aerosol particle monitor to characterize the size distribution of particles and culturable bacterial and fungal aerosols along the waterfront of a New York City embayment. We seek to address the potential contribution of bacterial aerosols from local sources and to determine how their number, size distribution, and taxonomic identity are affected by wind speed and wind direction (onshore vs. offshore. Total culturable microbial counts were higher under offshore winds (average of 778 CFU/m3 ± 67, with bacteria comprising the majority of colonies (58.5%, as compared to onshore winds (580 CFU/m3 ± 110 where fungi were dominant (87.7%. The majority of cultured bacteria and fungi sampled during both offshore winds (88% and onshore winds (72% were associated with coarse aerosols (>2.1 µm, indicative of production from local sources. There was a significant correlation (p < 0.05 of wind speed with both total and coarse culturable microbial aerosol concentrations. Taxonomic analysis, based on DNA sequencing, showed that Actinobacteria was the dominant phylum among aerosol isolates. In particular, Streptomyces and Bacillus, both spore forming genera that are often soil-associated, were abundant under both offshore and onshore wind conditions. Comparisons of bacterial communities present in the bioaerosol sequence libraries revealed that particle size played an important role in microbial aerosol taxonomy. Onshore and offshore coarse libraries were found to be most similar

Experimental Investigations of Effect of Sulphur on Beach Sand–Fly Ash–Asphalt (S-F-A Paving Mixes

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Satyakumar, M.

2013-01-01

Full Text Available The main components of the flexible pavements are asphalt and aggregates. But in most of the places in India there is shortage of the good quality aggregates (especially coarse aggregates, at the same time beach sand is available in plenty in many regions. Due to relative abundance of beach sand, the studies on the utilities of the beach sand in paving mixes are worth taking up. But beach Sand-Asphalt mix alone is not suitable for pavement construction, because of its low stability and high air voids. In the present study, Sand-Fly ash-Asphalt-Sulphur (S-F-A-S mixes are being made in different proportions and tested for their properties. Fatigue strength, stability, water sensitivity, stiffness modulus and dynamic modulus tests are carried out at standard test conditions and the results are analyzed for drawing conclusions. This study investigates the potential use of abundant ingredients, which may replace the ones which are scarce in nature.

Optimizing the use of natural gravel Brantas river as normal concrete mixed with quality fc = 19.3 Mpa

Science.gov (United States)

Limantara, A. D.; Widodo, A.; Winarto, S.; Krisnawati, L. D.; Mudjanarko, S. W.

2018-04-01

The use of natural gravel (rivers) as concrete mixtures is rarely encountered after days of demands for a higher strength of concrete. Moreover, today people have found High-Performance Concrete which, when viewed from the rough aggregate consisted mostly of broken stone, although the fine grain material still used natural sand. Is it possible that a mixture of concrete using natural gravel as a coarse aggregate is capable of producing concrete with compressive strength equivalent to a concrete mixture using crushed stone? To obtain information on this, a series of tests on concrete mixes with crude aggregates of Kalitelu Crusher, Gondang, Tulungagung and natural stone (river gravel) from the Brantas River, Ngujang, Tulungagung in the Materials Testing Laboratory Tugu Dam Construction Project, Kab. Trenggalek. From concrete strength test results using coarse material obtained value 19.47 Mpa, while the compressive strength of concrete with a mixture of crushed stone obtained the value of 21.12 Mpa.

Selenium bioavailability and uptake as affected by four different plants in a loamy clay soil with particular attention to mycorrhizae inoculated ryegrass

International Nuclear Information System (INIS)

Munier-Lamy, C.; Deneux-Mustin, S.; Mustin, C.; Merlet, D.; Berthelin, J.; Leyval, C.

2007-01-01

The aim of this study was to investigate the influence of plant species, especially of their rhizosphere soil, and of inoculation with an arbuscular mycorrhizal (AM) fungus on the bioavailability of selenium and its transfer in soil-plant systems. A pot experiment was performed with a loamy clay soil and four plant species: maize, lettuce, radish and ryegrass, the last one being inoculated or not with an arbuscular mycorrhizal fungus (Glomus mosseae). Plant biomass and Se concentration in shoots and roots were estimated at harvest. Se bioavailability in rhizosphere and unplanted soil was evaluated using sequential extractions. Plant biomass and selenium uptake varied with plant species. The quantity of rhizosphere soil also differed between plants and was not proportional to plant biomass. The highest plant biomass, Se concentration in plants, and soil to plant transfer factor were obtained with radish. The lowest Se transfer factors were obtained with ryegrass. For the latter, mycorrhizal inoculation did not significantly affect plant growth, but reduced selenium transfer from soil to plant by 30%. In unplanted soil after 65 days aging, more than 90% of added Se was water-extractable. On the contrary, Se concentration in water extracts of rhizosphere soil represented less than 1% and 20% of added Se for ryegrass and maize, respectively. No correlation was found between the water-extractable fraction and Se concentration in plants. The speciation of selenium in the water extracts indicated that selenate was reduced, may be under organic forms, in the rhizosphere soil

Phosphorus application to cotton enhances growth, yield, and quality characteristics on a sandy loam soil

International Nuclear Information System (INIS)

Ahmad, M.; Ranjha, A.M.

2009-01-01

Phosphorus (P) is the second most limiting nutrient in cotton (Gossypium hirsutum L.) production after nitrogen. Under wheat-cotton cropping system of Pakistan most of the farmers apply P fertilizer only to wheat crop. A field experiment was conducted to evaluate the effect of fertilizer P on the growth, yield and fibre quality of cotton on a sandy loam calcareous soil at farmer's field in cotton growing area of district Khanewal, Punjab. Five levels of P (0, 17, 26, 34 and 43 kg P ha /sup -1/) along with 120 kg N and 53 kg K ha/sup -1/ were applied. The response of cotton growth parameters was greater than quality components to P addition in calcareous soil. There was significant increase in the growth and yield parameters with each additional rate of P. The response of number of bolls per plant, boll weight and seed cotton yield was to the tune of 88.23, 16.82 and 42%, respectively at P application rate of 34 kg ha/sup -1/. Cotton quality components (lint %age, fiber length and fiber strength) improved from 2 to 5% where 43 kg P ha/sup -1/ was added. The lint and seed P concentration was little affected by P application as compared to stem and leaves showing its essentiality for cell division and development of meristematic tissue. Phosphorus use, thus not only valuable for wheat crop but also its application to cotton crop is of vital importance in improving both lint yield and quality. (author)

Wire-mesh capped deposition sensors: Novel passive tool for coarse fraction flux estimation of radon thoron progeny in indoor environments

International Nuclear Information System (INIS)

Mayya, Y.S.; Mishra, Rosaline; Prajith, Rama; Sapra, B.K.; Kushwaha, H.S.

2010-01-01

Deposition-based 222 Rn and 220 Rn progeny sensors act as unique, passive tools for determining the long time-averaged progeny deposition fluxes in the environment. The use of these deposition sensors as progeny concentration monitors was demonstrated in typical indoor environments as conceptually superior alternatives to gas-based indirect monitoring methods. In the present work, the dependency of these deposition monitors on various environmental parameters is minimized by capping the deposition sensor with a suitable wire mesh. These wire-mesh capped deposition sensors measure the coarse fraction deposition flux, which is less dependent on the change in environmental parameters like ventilation rate and turbulence. The calibration of these wire-mesh capped coarse fraction progeny sensors was carried out by laboratory controlled experiments. These sensors were deployed both in indoor and in occupational environments having widely different ventilation rates. The obtained coarse fraction deposition velocities were fairly constant in these environments, which further confirmed that the signal on the wire-mesh capped sensors show the least dependency on the change in environmental parameters. This technique has the potential to serve as a passive particle sizer in the general context of nanoparticles using progeny species as surrogates. On the whole, there exists a strong case for developing a passive system that responds only to coarse fraction for providing alternative tools for dosimetry and environmental fine particle research. - Research highlights: → Wire-mesh capped deposition sensor measures the coarse fraction deposition flux → Coarse fraction deposition flux less dependent on environmental conditions → Wire-mesh capped deposition sensor as passive particle sizer

Fouling of coarse-clastic sediments with macrophytes depending on the rate of abrasion, Murmansk coast

Science.gov (United States)

Malavenda, S. V.; Mitayev, M. V.; Malavenda, S. S.; Gerasimova, M. V.

2017-05-01

It is shown for the first time that the hydrodynamics and average daily gradient of air temperature affect the rate of abrasion of the coarse-clastic material on the boulder littoral of the Murmansk coast, as well as the density of its fouling by macroalgae. The proportion and biomass of species-explerents vary depending on the hydrological and meteorological conditions. The annual species-explerents ( Acrosiphonia arcta, Blidingia minima, Spongomorpha aeruginosa, Pylaiella littoralis) are the basis for new phytocenoses. In the fucus phytocenoses of the boulder littoral, these groupings represent the intermediate stage of fouling of the coarse-clastic material.

Adhesion between a rutile surface and a polyimide: a coarse grained molecular dynamics study

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Kumar, Arun; Sudarkodi, V.; Parandekar, Priya V.; Sinha, Nishant K.; Prakash, Om; Nair, Nisanth N.; Basu, Sumit

2018-04-01

Titanium, due to its high strength to weight ratio and polyimides, due to their excellent thermal stability are being increasingly used in aerospace applications. We investigate the bonding between a (110) rutile substrate and a popular commercial polyimide, PMR-15, starting from the known atomic structure of the rutile substrate and the architecture of the polymer. First, the long PMR-15 molecule is divided into four fragments and an all-atom non-bonded forcefield governing the interaction between PMR-15 and a rutile substrate is developed. To this end, parameters of Buckingham potential for interaction between each atom in the fragments and the rutile surface are fitted, so as to ensure that the sum of non-bonded and electrostatic interaction energy between the substrate and a large number of configurations of each fragment, calculated by the quantum mechanical route and obtained from the fitted potential, is closely matched. Further, two coarse grained models of PMR-15 are developed—one for interaction between two coarse grained PMR-15 molecules and another for that between a coarse grained PMR-15 and the rutile substrate. Molecular dynamics simulations with the coarse grained models yields a traction separation law—a very useful tool for conducting continuum level finite element simulations of rutile-PMR-15 joints—governing the normal separation of a PMR-15 block from a flat rutile substrate. Moreover, detailed information about the affinity of various fragments to the substrate are also obtained. In fact, though the separation energy between rutile and PMR-15 turns out to be rather low, our analysis—with merely the molecular architecture of the polyimide as the starting point—provides a scheme for in-silico prediction of adhesion energies for new polyimide formulations.

Pore-size distribution and compressibility of coarse sandy subsoil with added biochar

DEFF Research Database (Denmark)

Petersen, C. T.; Hansen, E.; Larsen, H. H.

2016-01-01

Sustainable agricultural production on coarse sandy soil is constrained by the restricted growth of roots, and poor water and nutrient retention. Amending the soil with biochar can reduce these problems, but the processes involved are not known in detail. We investigated in the laboratory...... the effects of two fine-grained gasification biochars made of straw (LTST) and other materials (LTSN) and of one fast pyrolysis straw biochar (FPST) on pore-size distribution and soil compressibility when added to coarse sandy subsoil. Water retention and therefore pore-size distribution were affected...... systematically. All biochars converted drainable pore space with pore diameters in the range 60–300 µm into water-retaining pores of size 0.2–60 µm, which was taken as an estimate of available water capacity (AWC). Effects were linear over the whole range of biochar (0–4% by mass). The effect of LTST and LTSN...

Isothermal coarse mixing: experimental and CFD modelling

International Nuclear Information System (INIS)

Gilbertson, M.A.; Kenning, D.B.R.; Hall, R.W.

1992-01-01

A plane, two-dimensional flow apparatus has been built which uses a jet of solid 6mm diameter balls to model a jet of molten drops falling into a tank of water to study premixing prior to a vapour explosion. Preliminary experiments with unheated stainless steel balls are here compared with computational fluid dynamics (CFD) calculations by the code CHYMES. (6 figures) (Author)

An eco-friendly self-compacting concrete with recycled coarse aggregates

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Pereira-de Oliveira, L. A.

2013-09-01

Full Text Available The potential uses of coarse recycled aggregates in the composition of SCC increases the ecological value and partly solve the issues of waste disposal sites generated by construction and demolition of structures. Thus, this paper present an experimental study of SCC properties where the normal coarse aggregates were replaced by different percentages of recycled aggregates, i.e., 0% (SCC, 10% (SCCR10, 20% (SCCR20, 30% (SCCR30 and 40% (SCCR40. The results from fresh concrete (rheological properties and self-compactability as the hardened concrete properties (compressive strength, density and dynamic modulus of elasticity, show only minor discrepancies. From the standpoint of mechanical behaviour, the results confirm the viability to incorporate coarse recycled aggregates in the SCC demonstrating the conservative character of the currently recommended limits.Los usos potenciales de áridos gruesos reciclados en la composición del hormigón autocompactante (SCC aumenta el valor ecológico y en parte resuelve los problemas de los sitios de disposición de residuos generados por la construcción y la demolición de las estructuras. Por lo tanto, este trabajo presenta un estudio experimental de las propiedades de SCC en el cual los áridos gruesos naturales fueron reemplazados por distintos porcentajes de áridos reciclados, es decir, 0% (SCC, el 10% (SCCR10, el 20% (SCCR20, el 30% (SCCR30 y el 40% (SCCR40. Los resultados del hormigón fresco (propiedades reológicas y la auto-compactación, como las propiedades de hormigón endurecido (resistencia a la compresión, densidad y módulo de elasticidad dinámico, muestran sólo pequeñas discrepancias. Desde el punto de vista del comportamiento mecánico, los resultados confirman la viabilidad de incorporar áridos gruesos reciclados en los SCC demostrando el carácter conservador de los límites actualmente recomendados.

Classical density functional theory & simulations on a coarse-grained model of aromatic ionic liquids.

Science.gov (United States)

Turesson, Martin; Szparaga, Ryan; Ma, Ke; Woodward, Clifford E; Forsman, Jan

2014-05-14

A new classical density functional approach is developed to accurately treat a coarse-grained model of room temperature aromatic ionic liquids. Our major innovation is the introduction of charge-charge correlations, which are treated in a simple phenomenological way. We test this theory on a generic coarse-grained model for aromatic RTILs with oligomeric forms for both cations and anions, approximating 1-alkyl-3-methyl imidazoliums and BF₄⁻, respectively. We find that predictions by the new density functional theory for fluid structures at charged surfaces are very accurate, as compared with molecular dynamics simulations, across a range of surface charge densities and lengths of the alkyl chain. Predictions of interactions between charged surfaces are also presented.

Ecology of coarse wood decomposition by the saprotrophic fungus Fomes fomentarius.

Science.gov (United States)

Větrovský, Tomáš; Voříšková, Jana; Snajdr, Jaroslav; Gabriel, Jiří; Baldrian, Petr

2011-07-01

Saprotrophic wood-inhabiting basidiomycetes are the most important decomposers of lignin and cellulose in dead wood and as such they attracted considerable attention. The aims of this work were to quantify the activity and spatial distribution of extracellular enzymes in coarse wood colonised by the white-rot basidiomycete Fomes fomentarius and in adjacent fruitbodies of the fungus and to analyse the diversity of the fungal and bacterial community in a fungus-colonised wood and its potential effect on enzyme production by F. fomentarius. Fungus-colonised wood and fruitbodies were collected in low management intensity forests in the Czech Republic. There were significant differences in enzyme production by F. fomentarius between Betula pendula and Fagus sylvatica wood, the activity of cellulose and xylan-degrading enzymes was significantly higher in beech wood than in birch wood. Spatial analysis of a sample B. pendula log segment proved that F. fomentarius was the single fungal representative found in the log. There was a high level of spatial variability in the amount of fungal biomass detected, but no effects on enzyme activities were observed. Samples from the fruiting body showed high β-glucosidase and chitinase activities compared to wood samples. Significantly higher levels of xylanase and cellobiohydrolase were found in samples located near the fruitbody (proximal), and higher laccase and Mn-peroxidase activities were found in the distal ones. The microbial community in wood was dominated by the fungus (fungal to bacterial DNA ratio of 62-111). Bacterial abundance composition was lower in proximal than distal parts of wood by a factor of 24. These results show a significant level of spatial heterogeneity in coarse wood. One of the explanations may be the successive colonization of wood by the fungus: due to differential enzyme production, the rates of biodegradation of coarse wood are also spatially inhomogeneous.

Mixed carbonate-siliciclastic sedimentation on a tectonically active margin: Example from the Pliocene of Baja California Sur, Mexico

Science.gov (United States)

Dorsey, Rebecca J.; Kidwell, Susan M.

1999-10-01

Bioclast-rich, coarse-grained deposits in the Pliocene Loreto basin provide a record of mixed carbonate and siliciclastic sedimentation at the steep hanging-wall margin of this small, fault-controlled basin. Sedimentary facies consist of sand- to gravel-sized carbonate debris mixed with volcaniclastic sand and gravel in a proximal to distal facies tract that includes matrix-rich and matrix-poor shelly conglomerate, impure calcirudite and calcarenite, mixed-composition turbidites, and bioturbated calcarenitic sandstone. Carbonate material was produced by mollusks and other benthic organisms on a narrow, high-energy shelf and mixed with volcaniclastic sand and gravel in cross-shelf channels. These mixtures were transported down a steep subaqueous slope by debris flows, grain flows, and turbidity currents, forming foresets and bottomsets of marine Gilbert-type deltas. This style of mixed carbonate-siliciclastic sedimentation has not been documented in detail elsewhere but should be locally abundant in the stratigraphic record of fault-bounded basins, particularly those with cool or nutrient-rich waters that support relatively few binding and framework-building faunas. Recognition of similar facies in other settings can provide useful insights into ancient conditions of carbonate production, oceanography, climate, and tectonics.

Effects of rumen-escape starch and coarseness of ingredients in pelleted concentrates on performance and rumen wall characteristics of rosé veal calves.

Science.gov (United States)

Vestergaard, M; Jarltoft, T C; Kristensen, N B; Børsting, C F

2013-08-01

The objective was to study the effect of rumen-escape starch and coarseness of ingredients in pelleted concentrates on performance, carcass quality and rumen wall characteristics in rosé veal calf production. Two alternative concentrates (Coarse and Slow) were compared with a traditional (Control) concentrate. Control was based on finely ground ingredients, whereas in Coarse, the same ingredients were coarsely ground resulting in a mean particle size before pelleting of 1.5 in Coarse and 0.6 mm in Control. Slow compared with Control and Coarse contained finely ground sorghum and corn instead of barley and wheat which increased the amount of rumen-escape starch to 59 compared with 22 g/kg in Control and Coarse. All concentrates had the same total starch (362 g/kg), NDF (168 g/kg), CP (154 g/kg) and DE (15.5 MJ/kg DM) content and a pellet diameter of 3.5 to 4 mm. Use of an 'indicator of starch digestibility' method gave a value of 98.6% for Control and Coarse and 91.1% for Slow (P 0.05). Papillae length and shape evaluated in atrium ruminis and the cranial part of the ventral rumen sac at slaughter were not affected by type of concentrate (P > 0.05). Rumen wall characteristics showed degrees of plaque formation (i.e., papillary aggregation), hyperaemia and necrotic areas in all treatment groups, but with no general difference between type of concentrate (P > 0.05). Incidence of liver abscesses (LAs, 16%) was not affected by type of concentrate (P > 0.05). There were no differences in performance or rumen wall characteristics between liver-abscessed and non-abscessed calves. The results show a high level of production performance with the three types of pelleted concentrates and indicates that neither the more coarse ingredients nor the additional rumen-escape starch tested, when fed ad libitum, could improve rumen wall characteristics or reduce LAs of rosé veal calves.

Uncertainty of Deardorff’s soil moisture model based on continuous TDR measurements for sandy loam soil

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Brandyk Andrzej

2016-03-01

Full Text Available Knowledge on soil moisture is indispensable for a range of hydrological models, since it exerts a considerable influence on runoff conditions. Proper tools are nowadays applied in order to gain in-sight into soil moisture status, especially of uppermost soil layers, which are prone to weather changes and land use practices. In order to establish relationships between meteorological conditions and topsoil moisture, a simple model would be required, characterized by low computational effort, simple structure and low number of identified and calibrated parameters. We demonstrated, that existing model for shallow soils, considering mass exchange between two layers (the upper and the lower, as well as with the atmosphere and subsoil, worked well for sandy loam with deep ground water table in Warsaw conurbation. GLUE (Generalized Likelihood Uncertainty Estimation linked with GSA (Global Sensitivity Analysis provided for final determination of parameter values and model confidence ranges. Including the uncertainty in a model structure, caused that the median soil moisture solution of the GLUE was shifted from the one optimal in deterministic sense. From the point of view of practical model application, the main shortcoming were the underestimated water exchange rates between the lower soil layer (ranging from the depth of 0.1 to 0.2 m below ground level and subsoil. General model quality was found to be satisfactory and promising for its utilization for establishing measures to regain retention in urbanized conditions.

Significant influence of fungi on coarse carbonaceous and potassium aerosols in a tropical rainforest

International Nuclear Information System (INIS)

Zhang, Zhisheng; Tao, Jun; Engling, Guenter; Zhang, Leiming; Kawamura, Kimitaka; Yang, Yihong; Zhang, Renjian; Chan, Chuen-yu; Li, Yide

2015-01-01

Fungal spores are ubiquitous in the Earth’s atmosphere, especially in the environment of tropical rainforests with intense biological activities. To assess the impact of fungi on chemical components of atmospheric aerosols at a Chinese tropical rainforest site, size-segregated fungal spore tracers (i.e. arabitol and mannitol) were measured along with major aerosol components, including carbonaceous species and water-soluble inorganic ions. The fungal spore tracers were found to be predominately associated with coarse particles, in which organic carbon (OC) and potassium (K + ) were also present at significant levels. Enhanced amounts of fungal spore tracers were closely linked to rainfall events. Moreover, fungal spore tracers exhibited positive correlations with relative humidity and negative correlations with wind speed, temperature or radiation. The relationships between fungal spore tracers and meteorological factors are consistent with the emission features of actively discharged fungal spores, which are generally associated with sugar alcohols and by-products such as the inorganic ion K + . The excellent correlations between fungal spore tracers and OC or K + in the coarse particles further suggested their common emission sources. Absolute principal factor analysis further identified fungi as the largest contributor to coarse OC and K + (both at ∼66%) in this rainforest. (letter)

Removal of micropollutants with coarse-ground activated carbon for enhanced separation with hydrocyclone classifiers.

Science.gov (United States)

Otto, N; Platz, S; Fink, T; Wutscherk, M; Menzel, U

2016-01-01

One key technology to eliminate organic micropollutants (OMP) from wastewater effluent is adsorption using powdered activated carbon (PAC). To avoid a discharge of highly loaded PAC particles into natural water bodies a separation stage has to be implemented. Commonly large settling tanks and flocculation filters with the application of coagulants and flocculation aids are used. In this study, a multi-hydrocyclone classifier with a downstream cloth filter has been investigated on a pilot plant as a space-saving alternative with no need for a dosing of chemical additives. To improve the separation, a coarser ground PAC type was compared to a standard PAC type with regard to elimination results of OMP as well as separation performance. With a PAC dosing rate of 20 mg/l an average of 64.7 wt% of the standard PAC and 79.5 wt% of the coarse-ground PAC could be separated in the hydrocyclone classifier. A total average separation efficiency of 93-97 wt% could be reached with a combination of both hydrocyclone classifier and cloth filter. Nonetheless, the OMP elimination of the coarse-ground PAC was not sufficient enough to compete with the standard PAC. Further research and development is necessary to find applicable coarse-grained PAC types with adequate OMP elimination capabilities.

Cyclic Behavior of Low Rise Concrete Shear Walls Containing Recycled Coarse and Fine Aggregates

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Qiyun Qiao

2017-12-01

Full Text Available In this study, the cyclic behaviors of low rise concrete shear walls using recycled coarse or fine aggregates were investigated. Eight low rise Recycled Aggregates Concrete (RAC shear wall specimens were designed and tested under a cyclic loading. The following parameters were varied: replacement percentages of recycled coarse or fine aggregates, reinforcement ratio, axial force ratio and X-shaped rebars brace. The failure characteristics, hysteretic behavior, strength and deformation capacity, strain characteristics and stiffness were studied. Test results showed that the using of the Recycled Coarse Aggregates (RCA and its replacement ratio had almost no influence on the mechanical behavior of the shear wall; however, the using of Recycled Fine Aggregates (RFA had a certain influence on the ductility of the shear wall. When the reinforcement ratio increased, the strength and ductility also increased. By increasing the axial force ratio, the strength increased but the ductility decreased significantly. The encased brace had a significant effect on enhancing the RAC shear walls. The experimental maximum strengths were evaluated with existing design codes, it was indicated that the strength evaluation of the low rise RAC shear walls can follow the existing design codes of the conventional concrete shear walls.

Experimental Investigation on Damping Property of Coarse Aggregate Replaced Rubber Concrete

Science.gov (United States)

Sugapriya, P.; Ramkrishnan, R.; Keerthana, G.; Saravanamurugan, S.

2018-02-01

Rubber has good damping and vibrational characteristics and can reduce cracking significantly due to its elastic nature. This property of rubber can be incorporated in concrete to control vibrations and create better pavements. Crumb Rubber on being dumped in landfills has serious repercussions and causes soil and land pollution. An innovative use of waste tires is shredding them into small pieces and using them as a replacement for coarse aggregate. Crumb rubber is obtained by chopping scrap tires, and in this study it was added in two different sets named SET 1 - Treated Crumb Rubber and concrete, and SET 2 - Treated Crumb rubber with Ultra Fine GGBS as admixture in concrete. Coarse aggregate replaces Rubber in each of the 2 SET’s in proportions of 5, 10, 15 and 20%. Properties like Compressive Strength, Young’s Modulus, Direct and Semi direct Ultrasonic Pulse Velocity, Sorptivity, Damping ratio and Frequency were found out. Deformation and mode shape were studied with modal analysis and static analysis by applying a uniform pressure corresponding to the highest compressive strength of the slab, using ANSYS.

Cover cropping to reduce nitrate loss through subsurface drainage in the northern U.S. corn belt.

Science.gov (United States)

Strock, J S; Porter, P M; Russelle, M P

2004-01-01

Despite the use of best management practices for nitrogen (N) application rate and timing, significant losses of nitrate nitrogen (NO3(-)-N) in drainage discharge continue to occur from row crop cropping systems. Our objective was to determine whether a autumn-seeded winter rye (Secale cereale L.) cover crop following corn (Zea mays L.) would reduce NO3(-)-N losses through subsurface tile drainage in a corn-soybean [Glycine mar (L.) Merr.] cropping system in the northern Corn Belt (USA) in a moderately well-drained soil. Both phases of the corn-soybean rotation, with and without the winter rye cover crop following corn, were established in 1998 in a Normania clay loam (fine-loamy, mixed, mesic Aquic Haplustoll) soil at Lamberton, MN. Cover cropping did not affect subsequent soybean yield, but reduced drainage discharge, flow-weighted mean nitrate concentration (FWMNC), and NO3(-)-N loss relative to winter fallow, although the magnitude of the effect varied considerably with annual precipitation. Three-year average drainage discharge was lower with a winter rye cover crop than without (p = 0.06). Over three years, subsurface tile-drainage discharge was reduced 11% and NO3(-)-N loss was reduced 13% for a corn-soybean cropping system with a rye cover crop following corn than with no rye cover crop. We estimate that establishment of a winter rye cover crop after corn will be successful in one of four years in southwestern Minnesota. Cover cropping with rye has the potential to be an effective management tool for reducing NO3(-)-N loss from subsurface drainage discharge despite challenges to establishment and spring growth in the north-central USA.

Hydraulic characterization of a sealed loamy soil in a Mediterranean vineyard

Science.gov (United States)

Alagna, Vincenzo; Di Prima, Simone; Bagarello, Vincenzo; Guaitoli, Fabio; Iovino, Massimo; Keesstra, Saskia; Cerdà, Artemi

2017-04-01

Water infiltration measurements constitute a common way for an indirect characterization of sealed/crusted soils (Alagna et al., 2013). The Beerkan Estimation of Soil Transfer (BEST) parameters procedure by Lassabatere et al. (2006) is very attractive for practical use since it allows an estimation of both the soil water retention and hydraulic conductivity functions. The BEST method considers certain analytical formulae for the hydraulic characteristic curves and estimates their shape parameters, which are texture dependent, from particle-size analysis by physical-empirical pedotransfer functions. Structure dependent scale parameters are estimated by a beerkan experiment, i.e. a three-dimensional (3D) field infiltration experiment at ideally zero pressure head. BEST substantially facilitates the hydraulic characterization of unsaturated soils, and it is gaining popularity in soil science (Bagarello et al., 2014a; Di Prima, 2015; Di Prima et al., 2016b). Bagarello et al. (2014b) proposed a beerkan derived procedure to explain surface runoff and disturbance phenomena at the soil surface occurring during intense rainfall events. Di Prima et al. (2016a) applied this methodology in a vineyard with a sandy-loam texture. These authors compared this simple methodology with rainfall simulation experiments establishing a physical link between the two methodologies through the kinetic energy of the rainfall and the gravitational potential energy of the water used for the beerkan runs. They also indirectly demonstrated the occurrence of a certain degree of compaction and mechanical breakdown using a minidisk infiltrometer (Decagon, 2014). With this device, they reported a reduction of the unsaturated hydraulic conductivity by 2.3 times, due to the seal formation. The ability of the BEST method to distinguish between crusted and non-crusted soils was demonstrated by Souza et al. (2014). However, the potential of the beerkan runs to detect the effect of the seal on flow and

Investigating the Effect of Soil Texture and Fertility on Evapotranspiration and Crop Coefficient of Maize Forage

Directory of Open Access Journals (Sweden)

M. Ghorbanian Kerdabadi

2017-02-01

fertility on middle Kc of maize was more than other stages of plant growth (Table 6. The obtained results showed that the addition of one and two percent fertilizer to the silty clay loam soil increased, the middle crop coefficient 13.3% and 27%, respectively in. Conclusion: Maximum and minimum effect of soil fertility on increasing crop coefficient of maize in the middle stage was equal to 37.8% in the loamy soil and 18.3% in the sandy loam soil with two percent fertilizer. The greatest effect of soil fertility on crop coefficient of maize was measured 8.37% in the middle stage of growth in LF2. The effect of soil fertility on crop coefficient of maize in loam and silty clay loam soils more than sandy loam soil, Because can be a further organic matter in these soils (loam and silty clay loam and also decreasing evaporation in sandy loam soil.

Controlling coarse woody debris inventory quality: taper and relative size methods

Science.gov (United States)

C.W. Woodall; J.A. Westfall

2008-01-01

Accurately measuring the dimensions of coarse woody debris (CWD) is critical for ensuring the quality of CWD estimates and, hence, for accurately estimating forest ecosystem attributes (e.g., CWD carbon stocks). To improve the quality of CWD dimensional measurements, the distribution of taper (ratio of change in diameter and length) and relative size (RS; ratio of...

Lessons Learned from Designing the Montium a Coarse-Grained Reconfigurable Processing Tile

NARCIS (Netherlands)

Smit, Gerardus Johannes Maria; Heysters, P.M.; Rosien, M.A.J.; Molenkamp, Egbert

2004-01-01

In this paper we describe in retrospective the main results of a four year project, called Chameleon. As part of this project we developed a coarse-grained reconfigurable core for DSP algorithms in wirelessdevices denoted MONTIUM. After presenting the main achievements within this project we present

Tamm Review: Sequestration of carbon from coarse woody debris in forest soils

NARCIS (Netherlands)

Magnússon, R.Í.; Tietema, A.; Cornelissen, J.H.C.; Hefting, M.M.; Kalbitz, K.

2016-01-01

Worldwide, forests have absorbed around 30% of global anthropogenic emissions of carbon dioxide (CO2) annually, thereby acting as important carbon (C) sinks. It is proposed that leaving large fragments of dead wood, coarse woody debris (CWD), in forest ecosystems may contribute to the forest C sink

Invertebrates Associated with Coarse Woody Debris in Streams, Upland Forests, and Wetlands: A Review

Science.gov (United States)

A. Braccia; D.P. Batzer

1999-01-01

We reviewed literature on the inbvertebrate groups associated with coarse woody debris in forests, streams, and wetlands, and contrasted patterns of invertebrate community development and wood decomposition among ecosystems.

Effects of Particle Size on the Shear Behavior of Coarse Grained Soils Reinforced with Geogrid

Directory of Open Access Journals (Sweden)

Daehyeon Kim

2014-02-01

Full Text Available In order to design civil structures that are supported by soils, the shear strength parameters of soils are required. Due to the large particle size of coarse-grained soils, large direct shear tests should be performed. In this study, large direct shear tests on three types of coarse grained soils (4.5 mm, 7.9 mm, and 15.9 mm were performed to evaluate the effects of particle size on the shear behavior of coarse grained soils with/without geogrid reinforcements. Based on the direct shear test results, it was found that, in the case of no-reinforcement, the larger the maximum particle size became, the larger the friction angle was. Compared with the no-reinforcement case, the cases reinforced with either soft geogrid or stiff geogrid have smaller friction angles. The cohesion of the soil reinforced with stiff geogrid was larger than that of the soil reinforced with soft geogrid. The difference in the shear strength occurs because the case with a stiff geogrid has more soil to geogrid contact area, leading to the reduction in interlocking between soil particles.

Remediating Contaminant Plumes in Groundwater with Shallow Excavations Containing Coarse Reactive Media.

Science.gov (United States)

Hudak, Paul F

2018-02-01

A groundwater flow and mass transport model tested the capability of shallow excavations filled with coarse, reactive media to remediate a hypothetical unconfined aquifer with a maximum saturated thickness of 5 m. Modeled as contaminant sinks, the rectangular excavations were 10 m downgradient of an initial contaminant plume originating from a source at the top of the aquifer. The initial plume was approximately 259 m long, 23 m wide, and 5 m thick, with a downgradient tip located approximately 100 m upgradient of the site boundary. The smallest trench capable of preventing offsite migration was 11 m long (measured perpendicular to groundwater flow), 4 m wide (measured parallel to groundwater flow), and 3 m deep. Results of this study suggest that shallow trenches filled with coarse filter media that partially penetrate unconfined aquifers may be a viable alternative for remediating contaminated groundwater at some sites.

Effect of mix design on the size-independent fracture energy of normal- and high-strength self-compacting concrete

Directory of Open Access Journals (Sweden)

H. Cifuentes

2018-02-01

Full Text Available Self-compacting concrete has a characteristic microstructure inherent to its specific composition. The higher content of fine particles in self-compacting concrete relative to the equivalent vibrated concrete produces a different fracture behavior that affects the main fracture parameters. In this work, a comprehensive experimental investigation of the fracture behavior of self-compacting concrete has been carried out. Twelve different self-compacting concrete mixes with compressive strength ranging from 39 to 124 MPa (wider range than in other studies have been subjected to three-point bending tests in order to determine the specific fracture energy. The influence of the mix design and its composition (coarse aggregate fraction, the water to binder ratio and the paste to solids ratio on its fracture behavior has been analyzed. Moreover, further evidence of the objectivity of the size-independent fracture energy results, obtained by the two most commonly used methods, has been provided on the self-compacting concrete mixes.

A coarse-grained polarizable force field for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

Science.gov (United States)

Zeman, Johannes; Uhlig, Frank; Smiatek, Jens; Holm, Christian

2017-12-01

We present a coarse-grained polarizable molecular dynamics force field for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]). For the treatment of electronic polarizability, we employ the Drude model. Our results show that the new explicitly polarizable force field reproduces important static and dynamic properties such as mass density, enthalpy of vaporization, diffusion coefficients, or electrical conductivity in the relevant temperature range. In situations where an explicit treatment of electronic polarizability might be crucial, we expect the force field to be an improvement over non-polarizable models, while still profiting from the reduction of computational cost due to the coarse-grained representation.

Parameterizing correlations between hydrometeor species in mixed-phase Arctic clouds

Science.gov (United States)

Larson, Vincent E.; Nielsen, Brandon J.; Fan, Jiwen; Ovchinnikov, Mikhail

2011-01-01

Mixed-phase Arctic clouds, like other clouds, contain small-scale variability in hydrometeor fields, such as cloud water or snow mixing ratio. This variability may be worth parameterizing in coarse-resolution numerical models. In particular, for modeling multispecies processes such as accretion and aggregation, it would be useful to parameterize subgrid correlations among hydrometeor species. However, one difficulty is that there exist many hydrometeor species and many microphysical processes, leading to complexity and computational expense. Existing lower and upper bounds on linear correlation coefficients are too loose to serve directly as a method to predict subgrid correlations. Therefore, this paper proposes an alternative method that begins with the spherical parameterization framework of Pinheiro and Bates (1996), which expresses the correlation matrix in terms of its Cholesky factorization. The values of the elements of the Cholesky matrix are populated here using a "cSigma" parameterization that we introduce based on the aforementioned bounds on correlations. The method has three advantages: (1) the computational expense is tolerable; (2) the correlations are, by construction, guaranteed to be consistent with each other; and (3) the methodology is fairly general and hence may be applicable to other problems. The method is tested noninteractively using simulations of three Arctic mixed-phase cloud cases from two field experiments: the Indirect and Semi-Direct Aerosol Campaign and the Mixed-Phase Arctic Cloud Experiment. Benchmark simulations are performed using a large-eddy simulation (LES) model that includes a bin microphysical scheme. The correlations estimated by the new method satisfactorily approximate the correlations produced by the LES.

Optimization of droplets for UV-NIL using coarse-grain simulation of resist flow

Science.gov (United States)

Sirotkin, Vadim; Svintsov, Alexander; Zaitsev, Sergey

2009-03-01

A mathematical model and numerical method are described, which make it possible to simulate ultraviolet ("step and flash") nanoimprint lithography (UV-NIL) process adequately even using standard Personal Computers. The model is derived from 3D Navier-Stokes equations with the understanding that the resist motion is largely directed along the substrate surface and characterized by ultra-low values of the Reynolds number. By the numerical approximation of the model, a special finite difference method is applied (a coarse-grain method). A coarse-grain modeling tool for detailed analysis of resist spreading in UV-NIL at the structure-scale level is tested. The obtained results demonstrate the high ability of the tool to calculate optimal dispensing for given stamp design and process parameters. This dispensing provides uniform filled areas and a homogeneous residual layer thickness in UV-NIL.

Effect of cooling rates on the weld heat affected zone coarse grain microstructure

Directory of Open Access Journals (Sweden)

Roman Celin

2018-04-01

Full Text Available The effect of a cooling rate on the S690Q quenched and tempered steel welded joint coarse grain heat affected zone microstructure was investigated using a dilatometer with controlled heating and cooling fixture. Steel samples were heated to a peak temperature of 1350 °C and cooled at the different cooling time Dt8/5. A dilatometric analysis and hardness measurements of the simulated thermal cycle coarse grain samples were done. Transformation start and finish temperature were determined using dilatation vs. temperature data analysis. The microstructure of the sample with a cooling time 5 s consists of martensite, whereas at cooling time 80 s a bainitic microstructure was observed. The investigated steel cooling cycle using simulation approach makes possible to determine the range of an optimum CG HAZ cooling time for the welding.

A Method Based on Semi-Solid Forming for Eliminating Coarse Dendrites and Shrinkage Porosity of H13 Tool Steel

Directory of Open Access Journals (Sweden)

Yifeng Guo

2018-04-01

Full Text Available A method called forging solidifying metal (FSM, which is applied for eliminating coarse dendrites and shrinkage porosity defects of ferrous alloys was proposed based on semi-solid forming technology (SSF. To verify its feasibility, the effects of liquid fraction (FL on the microstructure of the deformed H13 steel were investigated experimentally. The coarse dendrites structure still existed and cracks appeared when the 0.1/s 50% FSM method was carried out at ~20% FL. What is significantly different from that is, the elimination of the coarse dendrites structure and shrinkage porosity defects became more significant, when this method was conducted at the end of solidification (FL < 10%. The microstructure of H13 steel was significantly refined and also became dense in such condition.

Distribution of concentration of coarse particle-water mixture in horizontal smooth pipe

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří; Krupička, Jan

2016-01-01

Roč. 94, č. 6 (2016), s. 1040-1047 ISSN 0008-4034 R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : coarse particle-water mixture * gamma-ray radiometry * concentration distribution * horizontal conveying Subject RIV: BK - Fluid Dynamics Impact factor: 1.356, year: 2016

Distribution of concentration of coarse particle-water mixture in horizontal smooth pipe

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří; Krupička, Jan

2016-01-01

Roč. 94, č. 6 (2016), s. 1040-1047 ISSN 0008-4034 R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : coarse particle- water mixture * gamma-ray radiometry * concentration distribution * horizontal conveying Subject RIV: BK - Fluid Dynamics Impact factor: 1.356, year: 2016

Testing for entanglement with periodic coarse graining

Science.gov (United States)

Tasca, D. S.; Rudnicki, Łukasz; Aspden, R. S.; Padgett, M. J.; Souto Ribeiro, P. H.; Walborn, S. P.

2018-04-01

Continuous-variable systems find valuable applications in quantum information processing. To deal with an infinite-dimensional Hilbert space, one in general has to handle large numbers of discretized measurements in tasks such as entanglement detection. Here we employ the continuous transverse spatial variables of photon pairs to experimentally demonstrate entanglement criteria based on a periodic structure of coarse-grained measurements. The periodization of the measurements allows an efficient evaluation of entanglement using spatial masks acting as mode analyzers over the entire transverse field distribution of the photons and without the need to reconstruct the probability densities of the conjugate continuous variables. Our experimental results demonstrate the utility of the derived criteria with a success rate in entanglement detection of ˜60 % relative to 7344 studied cases.

Effect of Irrigation Water Type on Infiltration Rates of Sandy Soil

International Nuclear Information System (INIS)

Al-Omran, A.M.; Al-Matrood, S.M.; Choudhary, M.I.

2004-01-01

A laboratory experiment was conducted to test the effect of three water types (tap water, well water and sewage water) on the infiltration rate of three soils varying in texture (sand. loamy sand and sandy loam). A stationary rainfall simulator dispensing water at a rate of 45 mm h-1, connected to the different sources of water, was used to measure the infiltration rates. A total of 5 runs were carried out using each water quality. The volume of runoff against the time was recorded at each 5 minute interval. The infiltration rate was calculated as the difference between the water applied and the excesses water measured as surface runoff. Infiltration rate at first run were rapid in all the three soils and then progressively declined as the number of runs increased. The same trend was observed for each water quality tested. The reduction in infiltration rate with increasing number of runs for prewetted surface than for the initial dry surface was attributed to break down and settling of fine particles that took place earlier during prewetting. The infiltration curves for all the three soils when irrigared with different qualities of water was not distinguishable. The relationship between infiltration rate as function of time for the treatments applied were tested using Kostiakov equation I=bt-n. The infiltration data gave a coefficient of determination R2 >0.90 for all the treatments. The infiltration parameters B, and n varied strongly with respect to soil texture. Values of B decreased with changing soil textures, being highest for the sandy soil, and lowest for the sandy loamy soil, whereas n values showed the opposite trend. It was concluded that effect of soil texture on the infiltration rate was very pronounced while water qualities showed a little effect. (author)

CHARMM-GUI Martini Maker for Coarse-Grained Simulations with the Martini Force Field

NARCIS (Netherlands)

Qi, Yifei; Ingolfsson, Helgi I.; Cheng, Xi; Lee, Jumin; Marrink, Siewert J.; Im, Wonpil

Coarse-grained simulations are widely used to study large biological systems. Nonetheless, building such simulation systems becomes nontrivial, especially when membranes with various lipid types are involved. Taking advantage of the frameworks in all-atom CHARMM-GUI modules, we have developed

On the second law of thermodynamics: The significance of coarse-graining and the role of decoherence

International Nuclear Information System (INIS)

Noorbala, Mahdiyar

2014-01-01

We take up the question why the initial entropy in the universe was small, in the context of evolution of the entropy of a classical system. We note that coarse-graining is an important aspect of entropy evaluation which can reverse the direction of the increase in entropy, i.e., the direction of thermodynamic arrow of time. Then we investigate the role of decoherence in the selection of coarse-graining and explain how to compute entropy for a decohered classical system. Finally, we argue that the requirement of low initial entropy imposes constraints on the decoherence process

A 2.5-million-year perspective on coarse-filter strategies for conserving nature's stage.

Science.gov (United States)

Gill, Jacquelyn L; Blois, Jessica L; Benito, Blas; Dobrowski, Solomon; Hunter, Malcolm L; McGuire, Jenny L

2015-06-01

Climate change will require novel conservation strategies. One such tactic is a coarse-filter approach that focuses on conserving nature's stage (CNS) rather than the actors (individual species). However, there is a temporal mismatch between the long-term goals of conservation and the short-term nature of most ecological studies, which leaves many assumptions untested. Paleoecology provides a valuable perspective on coarse-filter strategies by marshaling the natural experiments of the past to contextualize extinction risk due to the emerging impacts of climate change and anthropogenic threats. We reviewed examples from the paleoecological record that highlight the strengths, opportunities, and caveats of a CNS approach. We focused on the near-time geological past of the Quaternary, during which species were subjected to widespread changes in climate and concomitant changes in the physical environment in general. Species experienced a range of individualistic responses to these changes, including community turnover and novel associations, extinction and speciation, range shifts, changes in local richness and evenness, and both equilibrium and disequilibrium responses. Due to the dynamic nature of species responses to Quaternary climate change, a coarse-filter strategy may be appropriate for many taxa because it can accommodate dynamic processes. However, conservationists should also consider that the persistence of landforms varies across space and time, which could have potential long-term consequences for geodiversity and thus biodiversity. © 2015 Society for Conservation Biology.

Disentangling effects of key coarse woody debris fuel properties on its combustion, consumption and carbon gas emissions during experimental laboratory fire

NARCIS (Netherlands)

Zhao, Weiwei; van Logtestijn, Richard S.P.; van der Werf, Guido R.; van Hal, Jurgen R.; Cornelissen, Johannes H.C.

2018-01-01

Coarse woody debris is a key terrestrial carbon pool, and its turnover through fire plays a fundamental role in global carbon cycling. Coarse dead wood fuel properties, which vary between tree species and wood decay stages, might affect its combustion, consumption and carbon gas emissions during

Multilevel Monte Carlo methods using ensemble level mixed MsFEM for two-phase flow and transport simulations

KAUST Repository

Efendiev, Yalchin R.

2013-08-21

In this paper, we propose multilevel Monte Carlo (MLMC) methods that use ensemble level mixed multiscale methods in the simulations of multiphase flow and transport. The contribution of this paper is twofold: (1) a design of ensemble level mixed multiscale finite element methods and (2) a novel use of mixed multiscale finite element methods within multilevel Monte Carlo techniques to speed up the computations. The main idea of ensemble level multiscale methods is to construct local multiscale basis functions that can be used for any member of the ensemble. In this paper, we consider two ensemble level mixed multiscale finite element methods: (1) the no-local-solve-online ensemble level method (NLSO); and (2) the local-solve-online ensemble level method (LSO). The first approach was proposed in Aarnes and Efendiev (SIAM J. Sci. Comput. 30(5):2319-2339, 2008) while the second approach is new. Both mixed multiscale methods use a number of snapshots of the permeability media in generating multiscale basis functions. As a result, in the off-line stage, we construct multiple basis functions for each coarse region where basis functions correspond to different realizations. In the no-local-solve-online ensemble level method, one uses the whole set of precomputed basis functions to approximate the solution for an arbitrary realization. In the local-solve-online ensemble level method, one uses the precomputed functions to construct a multiscale basis for a particular realization. With this basis, the solution corresponding to this particular realization is approximated in LSO mixed multiscale finite element method (MsFEM). In both approaches, the accuracy of the method is related to the number of snapshots computed based on different realizations that one uses to precompute a multiscale basis. In this paper, ensemble level multiscale methods are used in multilevel Monte Carlo methods (Giles 2008a, Oper.Res. 56(3):607-617, b). In multilevel Monte Carlo methods, more accurate

Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Beane, S; Detmold, W; Luu, T; Orginos, K; Parreno, A; Torok, A; Walker-Loud, A

2009-06-30

The {pi}{sup +}{Sigma}{sup +}, {pi}{sup +}{Xi}{sup 0}, K{sup +}p, K{sup +}n, {bar K}{sup 0}{Sigma}{sup +}, and {bar K}{sup 0}{Xi}{sup 0} scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find a{sub {pi}{sup +}{Sigma}{sup +}} = -0.197 {+-} 0.017 fm, and a{sub {pi}{sup +}{Xi}{sup 0}} = -0.098 {+-} 0.017 fm, where the comprehensive error includes statistical and systematic uncertainties.

Post-irradiation annealing of coarse-grained model alloys

Energy Technology Data Exchange (ETDEWEB)

Ray, P H.N.; Wilson, C; McElroy, R J [AEA Reactor Services, Harwell (United Kingdom)

1994-12-31

Thermal ageing and irradiation studies have been carried out on three model alloys (JPC, JPB, JPG) that have identical compositions except for different levels of phosphorus and/or copper. They have been irradiated in three conditions, as-received, heat treated to produce a coarse grained microstructure (similar to heat-affected-zone), and in this condition further aged at 450 C to produce a temper embrittled condition. One of the alloy have been subject to a post-irradiation anneal. The effect of these treatments on mechanical property changes has been characterized by Charpy testing and Vickers hardness measurements; the phosphorus segregation has been studied by a combination of STEM and Auger techniques.

Calculation of accurate small angle X-ray scattering curves from coarse-grained protein models

Directory of Open Access Journals (Sweden)

Stovgaard Kasper

2010-08-01

Full Text Available Abstract Background Genome sequencing projects have expanded the gap between the amount of known protein sequences and structures. The limitations of current high resolution structure determination methods make it unlikely that this gap will disappear in the near future. Small angle X-ray scattering (SAXS is an established low resolution method for routinely determining the structure of proteins in solution. The purpose of this study is to develop a method for the efficient calculation of accurate SAXS curves from coarse-grained protein models. Such a method can for example be used to construct a likelihood function, which is paramount for structure determination based on statistical inference. Results We present a method for the efficient calculation of accurate SAXS curves based on the Debye formula and a set of scattering form factors for dummy atom representations of amino acids. Such a method avoids the computationally costly iteration over all atoms. We estimated the form factors using generated data from a set of high quality protein structures. No ad hoc scaling or correction factors are applied in the calculation of the curves. Two coarse-grained representations of protein structure were investigated; two scattering bodies per amino acid led to significantly better results than a single scattering body. Conclusion We show that the obtained point estimates allow the calculation of accurate SAXS curves from coarse-grained protein models. The resulting curves are on par with the current state-of-the-art program CRYSOL, which requires full atomic detail. Our method was also comparable to CRYSOL in recognizing native structures among native-like decoys. As a proof-of-concept, we combined the coarse-grained Debye calculation with a previously described probabilistic model of protein structure, TorusDBN. This resulted in a significant improvement in the decoy recognition performance. In conclusion, the presented method shows great promise for

Analysis of coarse aggregate performance based on the modified Micro Deval abrasion test

Directory of Open Access Journals (Sweden)

Jiangfeng Wu

2018-03-01

Full Text Available The anti-abrasion property of aggregate significantly affects the performance of the pavement. In this research, the quartzite and gneiss which were produced in Lincheng County, Xingtai City, Hebei Province were selected as test samples. According to the American Society for Testing and Materials standard, the Micro-Deval abrasion test was taken every 1000 rotation times until 20,000 times, and the change trend of the Micro-Deval abrasion value was obtained. Results showed that the abrasion values were in the exponential growth rate rather than linear rate. Their R-Square coefficient was 0.99142 and 0.99916 respectively. The gravel information such as area, roundness, diameter, perimeter and so on were calculated and analyzed by Image-Pro Plus software, which provided a rapid way for the 2D morphology characteristics analysis of the coarse aggregate. Keywords: Micro-Deval abrasion test, Coarse aggregate, Anti-abrasion property, Abrasion values

USE OF THE “ROTHC” MODEL TO SIMULATE SOIL ORGANIC CARBON DYNAMICS ON A SILTY-LOAM INCEPTISOL IN NORTHERN ITALY UNDER DIFFERENT FERTILIZATION PRACTICES

Directory of Open Access Journals (Sweden)

Rosa Francaviglia

2014-01-01

Full Text Available We evaluated the efficiency of the RothC model to simulate Soil Organic Carbon (SOC dynamics after 12 years of organic and mineral fertilization practices in a study area located in northern Italy, on a silty-loam Inceptisol with a rotation including tomato, maize and alfalfa. The model performance was assessed by RMSE and EF coefficients. RothC simulated well observed SOC decreases in 71 samples (RMSE=7.42; EF=0.79, while performed with less accuracy when considering all samples (96 samples; RMSE=12.37; EF=0.58, due to the fact that the model failed in case of measured SOC increases (25 samples; RMSE=20.77; EF=-0.038. The model was used to forecast the SOC dynamics over a 50 year period under the same pedoclimatic conditions. Only clay contents >15% allowed to predict increasing levels of SOC respect to the starting values.

Coarse Grid Modeling of Turbine Film Cooling Flows Using Volumetric Source Terms

Science.gov (United States)

Heidmann, James D.; Hunter, Scott D.

2001-01-01

The recent trend in numerical modeling of turbine film cooling flows has been toward higher fidelity grids and more complex geometries. This trend has been enabled by the rapid increase in computing power available to researchers. However, the turbine design community requires fast turnaround time in its design computations, rendering these comprehensive simulations ineffective in the design cycle. The present study describes a methodology for implementing a volumetric source term distribution in a coarse grid calculation that can model the small-scale and three-dimensional effects present in turbine film cooling flows. This model could be implemented in turbine design codes or in multistage turbomachinery codes such as APNASA, where the computational grid size may be larger than the film hole size. Detailed computations of a single row of 35 deg round holes on a flat plate have been obtained for blowing ratios of 0.5, 0.8, and 1.0, and density ratios of 1.0 and 2.0 using a multiblock grid system to resolve the flows on both sides of the plate as well as inside the hole itself. These detailed flow fields were spatially averaged to generate a field of volumetric source terms for each conservative flow variable. Solutions were also obtained using three coarse grids having streamwise and spanwise grid spacings of 3d, 1d, and d/3. These coarse grid solutions used the integrated hole exit mass, momentum, energy, and turbulence quantities from the detailed solutions as volumetric source terms. It is shown that a uniform source term addition over a distance from the wall on the order of the hole diameter is able to predict adiabatic film effectiveness better than a near-wall source term model, while strictly enforcing correct values of integrated boundary layer quantities.

Coarse-Grained Modeling of Polyelectrolyte Solutions

Science.gov (United States)

Denton, Alan R.; May, Sylvio

2014-03-01

Ionic mixtures, such as electrolyte and polyelectrolyte solutions, have attracted much attention recently for their rich and challenging combination of electrostatic and non-electrostatic interparticle forces and their practical importance, from battery technologies to biological systems. Hydration of ions in aqueous solutions is known to entail ion-specific effects, including variable solubility of organic molecules, as manifested in the classic Hofmeister series for salting-in and salting-out of proteins. The physical mechanism by which the solvent (water) mediates effective interactions between ions, however, is still poorly understood. Starting from a microscopic model of a polyelectrolyte solution, we apply a perturbation theory to derive a coarse-grained model of ions interacting through both long-range electrostatic and short-range solvent-induced pair potentials. Taking these effective interactions as input to molecular dynamics simulations, we calculate structural and thermodynamic properties of aqueous ionic solutions. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

Coarse-grained models using local-density potentials optimized with the relative entropy: Application to implicit solvation

International Nuclear Information System (INIS)

Sanyal, Tanmoy; Shell, M. Scott

2016-01-01

Bottom-up multiscale techniques are frequently used to develop coarse-grained (CG) models for simulations at extended length and time scales but are often limited by a compromise between computational efficiency and accuracy. The conventional approach to CG nonbonded interactions uses pair potentials which, while computationally efficient, can neglect the inherently multibody contributions of the local environment of a site to its energy, due to degrees of freedom that were coarse-grained out. This effect often causes the CG potential to depend strongly on the overall system density, composition, or other properties, which limits its transferability to states other than the one at which it was parameterized. Here, we propose to incorporate multibody effects into CG potentials through additional nonbonded terms, beyond pair interactions, that depend in a mean-field manner on local densities of different atomic species. This approach is analogous to embedded atom and bond-order models that seek to capture multibody electronic effects in metallic systems. We show that the relative entropy coarse-graining framework offers a systematic route to parameterizing such local density potentials. We then characterize this approach in the development of implicit solvation strategies for interactions between model hydrophobes in an aqueous environment.

Coarse-grained electrostatic interactions of coronene: Towards the crystalline phase

Energy Technology Data Exchange (ETDEWEB)

Heinemann, Thomas, E-mail: thomas.heinemann@tu-berlin.de; Klapp, Sabine H. L., E-mail: klapp@physik.tu-berlin.de [Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Palczynski, Karol, E-mail: karol.palczynski@helmholtz-berlin.de; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Institut für Physik, Humboldt Universität zu Berlin, Newtonstraße 15, 12489 Berlin (Germany); Institut für Weiche Materie und Funktionale Materialen, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin (Germany)

2015-11-07

In this article, we present and compare two different, coarse-grained approaches to model electrostatic interactions of disc-shaped aromatic molecules, specifically coronene. Our study builds on our previous work [T. Heinemann et al., J. Chem. Phys. 141, 214110 (2014)], where we proposed, based on a systematic coarse-graining procedure starting from the atomistic level, an anisotropic effective (Gay-Berne-like) potential capable of describing van der Waals contributions to the interaction energy. To take into account electrostatics, we introduce, first, a linear quadrupole moment along the symmetry axis of the coronene disc. The second approach takes into account the fact that the partial charges within the molecules are distributed in a ring-like fashion. We then reparametrize the effective Gay-Berne-like potential such that it matches, at short distances, the ring-ring potential. To investigate the validity of these two approaches, we perform many-particle molecular dynamics simulations, focusing on the crystalline phase (karpatite) where electrostatic interaction effects are expected to be particularly relevant for the formation of tilted stacked columns. Specifically, we investigate various structural parameters as well as the melting transition. We find that the second approach yields consistent results with those from experiments despite the fact that the underlying potential decays with the wrong distance dependence at large molecule separations. Our strategy can be transferred to a broader class of molecules, such as benzene or hexabenzocoronene.

Coarse-grained electrostatic interactions of coronene: Towards the crystalline phase

International Nuclear Information System (INIS)

Heinemann, Thomas; Klapp, Sabine H. L.; Palczynski, Karol; Dzubiella, Joachim

2015-01-01

In this article, we present and compare two different, coarse-grained approaches to model electrostatic interactions of disc-shaped aromatic molecules, specifically coronene. Our study builds on our previous work [T. Heinemann et al., J. Chem. Phys. 141, 214110 (2014)], where we proposed, based on a systematic coarse-graining procedure starting from the atomistic level, an anisotropic effective (Gay-Berne-like) potential capable of describing van der Waals contributions to the interaction energy. To take into account electrostatics, we introduce, first, a linear quadrupole moment along the symmetry axis of the coronene disc. The second approach takes into account the fact that the partial charges within the molecules are distributed in a ring-like fashion. We then reparametrize the effective Gay-Berne-like potential such that it matches, at short distances, the ring-ring potential. To investigate the validity of these two approaches, we perform many-particle molecular dynamics simulations, focusing on the crystalline phase (karpatite) where electrostatic interaction effects are expected to be particularly relevant for the formation of tilted stacked columns. Specifically, we investigate various structural parameters as well as the melting transition. We find that the second approach yields consistent results with those from experiments despite the fact that the underlying potential decays with the wrong distance dependence at large molecule separations. Our strategy can be transferred to a broader class of molecules, such as benzene or hexabenzocoronene

Production and testing of HENDL-2.1/CG coarse-group cross-section library based on ENDF/B-VII.0

International Nuclear Information System (INIS)

Xu Dezheng; He Zhaozhong; Zou Jun; Zeng Qin

2010-01-01

A coarse-group coupled neutron and photon (27n + 21γ) cross-section library HENDL-2.1/CG, based on ENDF/B-VII.0 evaluate data source, has been produced by FDS Team in Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). HENDL-2.1/CG containing 350 nuclide cross-section files (from 1 H to 252 Cf) was generated in MATXS format with the NJOY processing system and then by compiling coarse-group problem-dependent format using the TRANSX code. In order to verify the availability and reliability of the HENDL-2.1/CG data library, requisite benchmark calculations were performed and compared with HENDL-2.0/MG fine-group coupled neutron and photon (175n + 42γ) cross-section library. In general, results using the coarse-group library showed similarly believable as fine-group library.

Role of Neutral Lipids in Tear Fluid Lipid Layer: Coarse-Grained Simulation Study

DEFF Research Database (Denmark)

Telenius, J.; Koivuniemi, A.; Kulovesi, P.

2012-01-01

Tear fluid lipid layer (TFLL) residing at the air-water interface of tears has been recognized to play an important role in the development of dry eye syndrome. Yet, the composition, structure, and mechanical properties of TFLL are only partly known. Here, we report results of coarse...

Study of UO2-10WT%Gd2O3 fuel pellets obtained by seeding method using AUC co-precipitation and mechanical mixing processes

International Nuclear Information System (INIS)

Lima, M.M.F.; Ferraz, W.B.A.; Santos, M.M. dos; Pinto, L.C.M.; Santos, A.

2008-01-01

The use of gadolinium and uranium mixed oxide as a nuclear fuel aims to obtain a fuel with a performance better than that of UO 2 fuel. In this work, seeding method was used to improve ionic diffusivity during sintering to produce high density pellets containing coarse grains by co-precipitation and mechanical mixing processes. Sintered UO 2 -10 wt% Gd 2 O 3 pellets were obtained using the reference processes with 2 wt% and 5 wt% UO 2 seeds with two granulometries, less than 20 μm and between 20 and 38 μm. Characterisation was carried out by chemical analysis, surface area, X-ray diffraction, SEM, WDS, image analysis, and densitometry. The seeding method using mechanical mixing process was more effective than the co-precipitation method. Furthermore, mechanical mixing process resulted in an increase in density of UO 2 -10wt% Gd 2 O 3 with seeds in relation to that of UO 2 -10wt% Gd 2 O 3 without seeds. (author)

Quick evaluation of multiple geostatistical models using upscaling with coarse grids: A practical study

Energy Technology Data Exchange (ETDEWEB)

Lemouzy, P. [Institut Francais du Petrole and ELF/IFP Helios Group, Pau (France)

1997-08-01

In field delineation phase, uncertainty in hydrocarbon reservoir descriptions is large. To quickly examine the impact of this uncertainty on production performance, it is necessary to evaluate a large number of descriptions in relation to possible production methods (well spacing, injection rate, etc.). The method of using coarse upscaled models was first proposed by Ballin. Unlike other methods (connectivity analysis, tracer simulations), it considers parameters such as PVT, well management, etc. After a detailed review of upscaling issues, applications to water-injection cases (either with balance or imbalance of production, with or without aquifer) and to depletion of an oil reservoir with aquifer coning are presented. Much more important than the method of permeability upscaling far from wells, the need of correct upscaling of numerical well representation is pointed out Methods are proposed to accurately represent fluids volumes in coarse models. Simple methods to upscale relative permeabilities, and methods to efficiently correct numerical dispersion are proposed. Good results are obtained for water injection. The coarse upscaling method allows the performance of sensitivity analyses on model parameters at a much lower CPU cost than comprehensive simulations. Models representing extreme behaviors can be easily distinguished. For depletion of an oil reservoir showing aquifer coning, however, the method did not work property. It is our opinion that further research is required for upscaling close to wells. We therefore recombined this method for practical use in the case of water injection.

Relationship of coarse woody debris to arthropod Availability for Red-Cockaded Woodpeckers and other bark-foraging birds on loblolly pine boles.

Energy Technology Data Exchange (ETDEWEB)

Horn, Scott; Hanula, James, L.

2008-04-01

Abstract This study determined if short-term removal of coarse woody debris would reduce prey available to red-cockaded woodpeckers (Picoides borealis Vieillot) and other bark-foraging birds at the Savannah River Site in Aiken and Barnwell counties, SC. All coarse woody debris was removed from four 9-ha plots of mature loblolly pine (Pinus taeda L.) in 1997 and again in 1998. We sampled arthropods in coarse woody debris removal and control stands using crawl traps that captured arthropods crawling up tree boles, burlap bands wrapped around trees, and cardboard panels placed on the ground. We captured 27 orders and 172 families of arthropods in crawl traps whereas 20 arthropod orders were observed under burlap bands and cardboard panels. The most abundant insects collected from crawl traps were aphids (Homoptera: Aphididae) and ants (Hymenoptera: Forrnicidae). The greatest biomass was in the wood cockroaches (Blattaria: Blattellidae), caterpillars (Lepidoptera) in the Family Noctuidae, and adult weevils (Coleoptera: Curculionidae). The most common group observed underneath cardboard panels was lsoptera (termites), and the most common taxon under burlap bands was wood cockroaches. Overall, arthropod abundance and biomass captured in crawl traps was similar in control and removal plots. In contrast, we observed more arthropods under burlap bands (mean & SE; 3,021.5 k 348.6, P= 0.03) and cardboard panels (3,537.25 k 432.4, P= 0.04) in plots with coarse woody debris compared with burlap bands (2325 + 171.3) and cardboard panels (2439.75 + 288.9) in plots where coarse woody debris was removed. Regression analyses showed that abundance beneath cardboard panels was positively correlated with abundance beneath burlap bands demonstrating the link between abundance on the ground with that on trees. Our results demonstrate that short-term removal of coarse woody debris from pine forests reduced overall arthropod availability to bark-foraging birds.

Consumer clusters in Denmark based on coarse vegetable intake frequency, explained by hedonics, socio-demographic, health and food lifestyle factors. A cross-sectional national survey.

Science.gov (United States)

Beck, Tove K; Jensen, Sidsel; Simmelsgaard, Sonni Hansen; Kjeldsen, Chris; Kidmose, Ulla

2015-08-01

Vegetable intake seems to play a protective role against major lifestyle diseases. Despite this, the Danish population usually eats far less than the recommended daily intake. The present study focused on the intake of 17 coarse vegetables and the potential barriers limiting their intake. The present study drew upon a large Danish survey (n = 1079) to study the intake of coarse vegetables among Danish consumers. Four population clusters were identified based on their intake of 17 different coarse vegetables, and profiled according to hedonics, socio-demographic, health, and food lifestyle factors. The four clusters were characterized by a very low intake frequency of coarse vegetables ('low frequency'), a low intake frequency of coarse vegetables; but high intake frequency of carrots ('carrot eaters'), a moderate coarse vegetable intake frequency and high intake frequency of beetroot ('beetroot eaters'), and a high intake frequency of all coarse vegetables ('high frequency'). There was a relationship between reported liking and reported intake frequency for all tested vegetables. Preference for foods with a sweet, salty or bitter taste, in general, was also identified to be decisive for the reported vegetable intake, as these differed across the clusters. Each cluster had distinct socio-demographic, health and food lifestyle profiles. 'Low frequency' was characterized by uninvolved consumers with lack of interest in food, 'carrot eaters' vegetable intake was driven by health aspects, 'beetroot eaters' were characterized as traditional food consumers, and 'high frequency' were individuals with a strong food engagement and high vegetable liking. 'Low frequency' identified more barriers than other consumer clusters and specifically regarded low availability of pre-cut/prepared coarse vegetables on the market as a barrier. Across all clusters a low culinary knowledge was identified as the main barrier. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coarse-grained forms for equations describing the microscopic motion of particles in a fluid.

Science.gov (United States)

Das, Shankar P; Yoshimori, Akira

2013-10-01

Exact equations of motion for the microscopically defined collective density ρ(x,t) and the momentum density ĝ(x,t) of a fluid have been obtained in the past starting from the corresponding Langevin equations representing the dynamics of the fluid particles. In the present work we average these exact equations of microscopic dynamics over the local equilibrium distribution to obtain stochastic partial differential equations for the coarse-grained densities with smooth spatial and temporal dependence. In particular, we consider Dean's exact balance equation for the microscopic density of a system of interacting Brownian particles to obtain the basic equation of the dynamic density functional theory with noise. Our analysis demonstrates that on thermal averaging the dependence of the exact equations on the bare interaction potential is converted to dependence on the corresponding thermodynamic direct correlation functions in the coarse-grained equations.

Formation of incoherent deformation twin boundaries in a coarse-grained Al-7Mg alloy

Science.gov (United States)

Jin, S. B.; Zhang, K.; Bjørge, R.; Tao, N. R.; Marthinsen, K.; Lu, K.; Li, Y. J.

2015-08-01

Deformation twinning has rarely been observed in coarse grained Al and its alloys except under some extreme conditions such as ultrahigh deformation strain or strain rates. Here, we report that a significant amount of Σ3 deformation twins could be generated in a coarse-grained Al-7 Mg alloy by dynamic plastic deformation (DPD). A systematic investigation of the Σ3 boundaries shows that they are Σ3{112} type incoherent twin boundaries (ITBs). These ITBs have formed by gradual evolution from copious low-angle deformation bands through -twist Σ boundaries by lattice rotation. These findings provide an approach to generate deformation twin boundaries in high stacking fault energy metallic alloys. It is suggested that high solution content of Mg in the alloy and the special deformation mode of DPD played an important role in formation of the Σ and ITBs.

Coarse Particulate Organic Matter: Storage, Transport, and Retention

Energy Technology Data Exchange (ETDEWEB)

Tiegs, Scott [Oakland University, Rochester, MI; Lamberti, Gary A. [University of Notre Dame, IN; Entrekin, Sally A. [University of Central Arkansas; Griffiths, Natalie A. [ORNL

2017-08-01

Coarse particulate organic matter, or CPOM, is a basal energy and nutrient resource in many stream ecosystems and is provided by inputs from the riparian zone, incoming tributaries, and to a lesser extent from in-stream production. The ability of a stream to retain CPOM or slow its transport is critical to its consumption and assimilation by stream biota. In this chapter, we describe basic exercises to measure (1) the amount of CPOM in the streambed and (2) the retention of CPOM from standardized particle releases. We further describe advanced exercises that (1) experimentally enhance the retentiveness of a stream reach and (2) measure organic carbon transport and turnover (i.e., spiraling) in the channel.

Coarse Particulate Organic Matter: Storage, Transport, and Retention

Energy Technology Data Exchange (ETDEWEB)

Tiegs, Scott [Oakland University, Rochester, MI; Lamberti, Gary A. [University of Notre Dame, IN; Entrekin, Sally A. [University of Central Arkansas; Griffiths, Natalie A. [ORNL

2017-06-01

Coarse particulate organic matter, or CPOM, is a basal energy and nutrient resource in many stream ecosystems and is provided by inputs from the riparian zone, incoming tributaries, and to a lesser extent from in-stream production. The ability of a stream to retain CPOM or slow its transport is critical to its consumption and assimilation by stream biota. In this chapter, we describe basic exercises to measure (1) the amount of CPOM in the streambed and (2) the retention of CPOM from standardized particle releases. We further describe advanced exercises that (1) experimentally enhance the retentiveness of a stream reach and (2) measure organic carbon transport and turnover (i.e., spiraling) in the channel.