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Sample records for sand lacks effective

  1. A Laboratory Experiment on the Evolution of a Sand Gravel Reach Under a Lack of Sediment Supply

    Science.gov (United States)

    Orru, C.; Chavarrias, V.; Ferrara, V.; Blom, A.

    2014-12-01

    A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. The experimental data are used to validate a numerical sand-gravel model. A bed composed of a bi-modal sediment mixture is installed with a uniform slope and an imposed gradual fining pattern. Initially, the sand fraction gradually increases in streamwise direction until the bed is fully composed of sand. The water discharge and downstream water level were constant, and the sediment feed rate was equal to zero. The experiment was dominated by bed load, partial transport, and a subcritical flow regime was imposed. The flow rate was such that only sand was mobile (partial transport), which led to a coarsening over the upstream reach and a gradual reduction of the sediment transport rate during the experiment. New equipment was used to measure the evolution of the grain size distribution of the bed surface during the experiment over the entire flume using image analysis. In the upstream reach we observed a gradual coarsening over time and the formation of an armour layer, which resulted in a more abrupt transition in grain size of the bed surface. Bed degradation increased in streamwise direction. This is due to the initial streamwise increase in the availability of sand in the bed. The different volume fraction content of sand in the bed allowed for the gravel to sink more in the downstream part of the upstream reach. The sand reach suffered from a larger degradation. Finally, we see one reach dominated by sand, small bedforms, and a small bed slope, and a gravel reach dominated by a larger bed slope.

  2. A laboratory experiment on the evolution of a sand gravel reach under a lack of sediment supply

    NARCIS (Netherlands)

    Orru, C.; Chavarrias Borras, V.; Ferrara, V.; Stecca, G.; Blom, A.

    2015-01-01

    A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. A bed composed of a bimodal sediment mixture was installed with a uniform slope and an gradual fining pattern. At the upstream end of the flume the initial bed consisted of 100% gravel,

  3. Displacement pile installation effects in sand

    NARCIS (Netherlands)

    Beijer-Lundberg, A.

    2015-01-01

    Installation effects govern the post-installation behaviour of displacement piles in sand. These effects are currently not completely understood. Suitable experimental techniques to model these installation effects include field, laboratory and experimental models. In the current thesis a small-scal

  4. DYNAMIC EFFECTIVE SHEAR STRENGTH OF SATURATED SAND

    Institute of Scientific and Technical Information of China (English)

    邵生俊; 谢定义

    2002-01-01

    The dynamic effective shear strength of saturated sand under cyclic loading is discussed in this paper. The discussion includes the transient time dependency behaviors based on the analysis of the results obtained in conventional cyclic triaxial tests and cyclic torsional shear triaxial tests. It has been found that the dynamic effective shear strength is composed of effective frictional resistance and viscous resistance, which are characterized by the strain rate dependent feature of strength magnitude, the coupling of consolidation stress with cyclic stress and the dependency of time needed to make the soil strength suffciently mobilized, and can also be expressed by the extended Mohr-Coulomb's law. The two strength parameters of the dynamic effective internal frictional angle φd and the dynamic viscosity coefficient η are determined. The former is unvaried for different number of cyclic loading, dynamic stress form and consolidation stress ratio. And the later is unvaried for the different dynamic shear strain rate γt developed during the sand liquefaction, but increases with the increase of initial density of sand. The generalization of dynamic effective stress strength criterion in the 3-dimensional effective stress space is studied in detail for the purpose of its practical use.

  5. Effect of Chromite-Silica Sands Characteristics on Performance of Ladle Filler Sands for Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Free opening rate is mainly determined by the performance of the ladle filler sand. High free opening rates of ladles are required in steel making to improve steel quality. Chromite ladle filler sands are one of the most widely used ladle filler sand. Several operative variables and materials characteristics affect the performance of the sands. Three sets of chromite ladle filler sands were selected and researches were focused on the sintering hehaviour and per- formance of the sands under operative conditions. The effect of particle size distribution on sintering, microstruc- ture, flowability, and permeability were presented. In all cases, the particle size varies from 0.1 to 1.5 mm corre- sponding to free flowing powders. One of the samples has higher permeability factor in comparison with others due to low particle size distribution. The other sample presents very good free opening due to its very good flowability and permeability factor.

  6. The cumulative effects of using fine particles and cyanobacteria for rehabilitation of disturbed active sand dunes

    Science.gov (United States)

    Zaady, Eli; Katra, Itzhak; Barkai, Daniel; Knoll, Yaakov; Sarig, Shlomo

    2016-04-01

    One of the main problems in desertified lands worldwide is active wind-borne sand dunes, which lead to covering of fertile soils and agricultural fields. In regions with more than 100 mm of annual rainfall, sand dunes may be naturally stabilized by biocrusts (biological soil crusts). One of the main restraints of biocrust development is the typical lack of fine particles in sand dunes. Our study investigated the combined application of fine particles [coal fly-ash <100 micrometer] and bio-inoculant of filamentous cyanobacteria, isolated from nearby natural stabilized sand dunes, on the soil surface of active sands for increasing resistance to wind erosion. Boundary-layer wind tunnel experiments were conducted in experimental plots within a greenhouse for examining the effects of adding coal fly-ash and bio-inoculant to active sands. The biocrust development was evaluated via several physical and bio-physiological variables. In all the physical measurements and the bio-physiological variables, the treatment of "sand+inoculum+coal fly-ash" showed significant differences from the "sand-control". The combination led to the best results of surface stabilization in boundary-layer wind tunnel experiments, with the lowest sand fluxes. The filamentous cyanobacteria use the fine particles of the coal fly-ash as bridges for growing toward and adhering to the large sand particles. The cumulative effects of biocrusts and coal fly-ash enhance soil surface stabilization and may allow long-term sustainability.

  7. Effects of advanced oxidation on green sand properties via iron casting into green sand molds.

    Science.gov (United States)

    Wang, Yujue; Cannon, Fred S; Voigt, Robert C; Komarneni, Sridhar; Furness, J C

    2006-05-01

    The effects of advanced oxidation (AO) processing on the properties of green sand were studied via pouring cast iron into green sand molds. Upon cooling, the green sand molds were autopsied at various distances from the metal-sand interface. Autopsy green sand samples collected from a mold that incorporated AO water were characterized and compared to controlled samples collected from a similar autopsied mold made with conventional tap water (TAP). It was found that the AO processing removed a coating of coal pyrolysis products from the clay surface that typically accumulated on the clay surface. As a result, the AO-conditioned green sand retained 10-15% more active clay as measured bythe standard ultrasonic methylene blue titration than did the TAP-conditioned green sand. The AO processing also nearly doubled the generation of activated carbon from the normalized amount of coal composition of the green sand during the casting process. The AO-enhanced activated carbon generation and the AO-incurred clay surface cleaning provided the AO-conditioned green sand with higher normalized pore volume, and thus higher normalized m-xylene adsorption capacity, i.e., relative to before-metal-pouring conditions. Furthermore, mathematical analysis indicated that the AO-conditioned green sand better retained its important properties after pouring than did the TAP-conditioned green sand. Effectively, this meant after metal pouring, the AO-conditioned sample offered about the same net properties as the TAP-conditioned sample, even though the AO-conditioned sample contained less clay and coal before metal pouring. These results conformed to the full-scale foundry empirical finding that when AO is used, foundries need less makeup clay and coal addition through each casting cycle, and they release less air emissions.

  8. Strength and sintering effects at ejection of explosively driven sand

    Science.gov (United States)

    Resnyansky, A. D.; Weckert, S. A.

    2014-05-01

    A description of the response of sand to extreme loads is very important for the evaluation of the sand ejecta impact effects on various targets. Sand is a complex material to simulate because of its porosity where the inter-phase equilibrium is hard to achieve under transient shock wave loading. A previously developed two-phase model with strength has been implemented in CTH and applied to sand. The shock response of the sand, including the Hugoniot abnormality known from the literature for highly porous silica, is adequately described with the material model. The sand unloading effects appearing as the ejecta are observed in the present work using dynamic flash X-ray of an aluminium target plate loaded by limestone sand ejecta from the detonation of a buried high explosive charge. The CTH modelling results compared with the flash X-ray images have demonstrated good agreement, particularly, in the description of momentum transfer to the target.

  9. Review of four major environmental effects monitoring programs in the oil sands region

    Energy Technology Data Exchange (ETDEWEB)

    Lott, E.O.; Jones, R.K. [EO Consulting, BC (Canada)

    2010-10-15

    The lack of knowledge on current environmental effects monitoring programs for the mineable oil sands region generates a low public confidence in environment health monitoring and reporting programs for the oil sands operations. In 2010, the Oil Sands Research and Information Network (OSRIN) supervised a study reviewing the major environmental effects monitoring programs that are underway in the Regional Municipality of Wood Buffalo. Four main environmental effects monitoring and reporting organizations existing in the oil sands area were engaged to describe their programs through this study: Alberta Biodiversity Monitoring Institute (ABMI), Cumulative Environmental Management Association (CEMA), Regional Aquatic Monitoring Program (RAMP), Wood Buffalo Environmental Association (WBEA). These different organizations have specific roles in providing information, data and understanding of ecosystem effects. A one page visual summary of environmental effects monitoring in the oil sands area resulted from the information received from these organizations and detailed fact sheets were presented for each one of the programs. The report of this study also presents seven other environmental monitoring initiatives or organizations such as Alberta Environment and Environment Canada environmental effects monitoring program. The main observation that emerged from the review was the lack of detailed understanding shown by the stakeholders regarding the monitoring activities performed in the oil sands area. There is a lack of communication of the different programs that are conducted in the region. The study also pointed out that no efforts were put in cross-linking the various programs to be assured that every concerns related to environmental effects associated with oil sands operations were addressed. A better understanding of environmental effects and an improvement in public confidence in the data and its interpretation would probably be observed with the establishment of a

  10. The effects of psammophilous plants on sand dune dynamics

    CERN Document Server

    Bel, Golan

    2013-01-01

    Psammophilous plants are special plants that flourish in sand moving environments. There are two main mechanisms by which the wind affects these plants: (i) sand drift exposes roots and covers branches--the exposed roots turn into new plants and the covered branches turn into new roots; both mechanisms result in an enhanced growth rate of the psammophilous plant cover of the dunes; (ii) strong winds, often associated with sand movement, tear branches and seed them in nearby locations, resulting in new plants and an enhanced growth rate of the psammophilous plant cover of the dunes. Despite their important role in dune dynamics, to our knowledge, psammophilous plants have never been incorporated into mathematical models of sand dunes. Here, we attempt to model the effects of these plants on sand dune dynamics. We construct a set of three ordinary differential equations for the fractions of surface cover of regular vegetation, biogenic soil crust and psammophilous plants. The latter reach their optimal growth u...

  11. Lack of spacing effects during piano learning.

    Science.gov (United States)

    Wiseheart, Melody; D'Souza, Annalise A; Chae, Jacey

    2017-01-01

    Spacing effects during retention of verbal information are easily obtained, and the effect size is large. Relatively little evidence exists on whether motor skill retention benefits from distributed practice, with even less evidence on complex motor skills. We taught a 17-note musical sequence on a piano to individuals without prior formal training. There were five lags between learning episodes: 0-, 1-, 5-, 10-, and 15-min. After a 5-min retention interval, participants' performance was measured using three criteria: accuracy of note playing, consistency in pressure applied to the keys, and consistency in timing. No spacing effect was found, suggesting that the effect may not always be demonstrable for complex motor skills or non-verbal abilities (timing and motor skills). Additionally, we taught short phrases from five songs, using the same set of lags and retention interval, and did not find any spacing effect for accuracy of song reproduction. Our findings indicate that although the spacing effect is one of the most robust phenomena in the memory literature (as demonstrated by verbal learning studies), the effect may vary when considered in the novel realm of complex motor skills such as piano performance.

  12. Effects of the mid-air collision on sand saltation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    As to the fact that the effects of saltating particles’ mid-air collision on the sand transport rate are often neglected in the current theoretical models describing sand saltation movement,expressions to calculate velocity diversity of saltating parti-cles after mid-air collision are presented through collision theory of hard ball in this paper. Then,the theoretical model of the wind blown sand movement at the steady state,taking account of coupled interaction between saltation particles and wind,is combined with the model of the mid-air collision probability to calculate the sal-tating particles’ mass flux at heights,the sand transport rate,and further,their changing rules. The comparison of the results with those when the mid-air collision is not considered suggests that the mass flux at heights and the sand transport rate in this paper are less,and much closer,respectively,to the corresponding experi-mental values. The difference between the sand mass fluxes without and with con-sideration of mid-air collision increases at first,and then decreases as the height increases,exhibiting the stratified characteristics.

  13. Sand Fences in the Coastal Zone: Intended and Unintended Effects

    Science.gov (United States)

    Grafals-Soto, Rosana; Nordstrom, Karl

    2009-09-01

    Sand-trapping fences modify the character of the coastal landscape and change its spatial structure, image, and meaning. This paper examines the relationship between these changes and fence usage at the municipal level, where most decisions about fence deployment are made. Use of fences in 29 municipalities on the developed coast of New Jersey is examined over a 6-year period. Interviews with municipal officers indicate that wooden slat sand-trapping fences are used primarily to build dunes to provide protection against wave uprush and flooding, but they are also used to control pedestrian traffic and demarcate territory. These uses result in changes in landforms and habitats. An aerial video inventory of fences taken in 2002 indicates that 82% of the shoreline had fences and 72% had dunes. Single and double straight fence rows are the most commonly used. Fences are often built to accomplish a specific primary purpose, but they can cause many different and often unanticipated changes to the landscape. The effects of a sand fence change through time as the initial structure traps sand, creates a dune that is colonized by vegetation, and becomes integrated into the environment by increasing topographic variability and aesthetic and habitat value. Sand fences can be made more compatible with natural processes by not placing them in locations where sources of wind blown sand are restricted or in unnatural shore perpendicular orientations. Symbolic fences are less expensive, are easy to replace when damaged, are less visually intrusive, and can be used for controlling pedestrian access.

  14. Effects of oil sands sediments on fish

    Energy Technology Data Exchange (ETDEWEB)

    Parrott, J.; Colavecchia, M.; Hewitt, L.; Sherry, J.; Headley, J. [Environment Canada, Ottawa, ON (Canada); Turcotte, D.; Liber, K. [Saskatchewan Univ., Regina, SK (Canada)

    2010-07-01

    This paper described a collaborative project organized by Natural Resources Canada (NRCan) Panel of Energy Research and Development (PERD) with researchers from Environment Canada and the University of Saskatchewan. The 4-year study was conducted to assess the toxicity of oil sands sediments and river waters, and reclamation ponds and sediments on laboratory-raised fish. Three sediments from rivers were evaluated for their potential to cause adverse impacts on fathead minnow eggs and larvae for a period of 18 days. The study monitored hatching, larval survival, development, and growth. Naphthenic acids (NA), polycyclic aromatic hydrocarbons (PAHs) and metals were measured in the sediments to determine if the compounds can be correlated with observed toxicity. The study will also assess walleye eggs exposed to sediments, and in situ fish exposures. Toxicity identification and evaluation (TIE) studies will be conducted to isolate the fractions that may affect fish development and growth.

  15. Laboratory investigation of the loading rate effects in sand

    NARCIS (Netherlands)

    Huy, N.Q.; Van Tol, A.F.; Hölscher, P.

    2006-01-01

    In order to improve the interpretation of the quasi-static (e.g. Statnamic) pile load tests, a research project has been started to investigate effects of the loading rate on the bearing capacity of a pile in sand. A series of laboratory tests has been carried out. The testing program consists of a

  16. Effects of sand burial on dune plants:a review

    Institute of Scientific and Technical Information of China (English)

    Hao Qu; HaLin Zhao; RuiLian Zhou

    2014-01-01

    Burial of different growth stages of plants (e.g., adult plants, seedlings and seeds) is frequent in dune ecosystems. The soil micro-environment, which differs from surface conditions, influences the survival and growth of dune plants. To sum up knowledge about the survival mechanisms of plants under sand burial and to promote practical rehabilitation of dune vegetation, we reviewed relevant published literature and concluded that:(1) Focus in recent years has been on impacts of sand burial on seed germination and seedling emergence. Generally, shallow burial increased seed germination and seed-ling emergence, but deeper burial was negative. Buried at the same depth, large seeds showed higher germination and seedling emergence rates, attributed to larger energy reserves. (2) Survival, growth and reproduction rates of dune plants show plasticity in response to sand burial. Long-term deep burial is fatal because it creates a physical barrier which overcomes the vertical growth of plants, reduces photosynthetic leaf area, and limits oxygen availability to roots. Modest burial, on the other hand, is advantageous for growth and reproduction of many dune plants, due to protection from ex-cessive temperature and drought. (3) There are few reports concerning effects of sand burial on plant physiology, but a limited number of studies indicate that partial burial increases water use efficiency, chlorophyll content, transpiration rate and net photosynthetic rates. The antioxidant protective enzyme system and osmolyte balance were reported to be involved in the mechanisms of dune plant resistance to burial.

  17. Effectiveness of Protective Action of Coatings from Moisture Sorption into Surface Layer of Sand Moulds

    Directory of Open Access Journals (Sweden)

    Kaźnica N.

    2016-12-01

    Full Text Available The results of investigations of the sorption process of surface layers of sand moulds covered by zirconium and zirconium - graphite alcohol coatings are presented in the paper. Investigations comprised two kinds of sand grains (silica sand and reclaimed sand of moulding sand with furan resin. Tests were performed under conditions of a high relative air humidity 75 - 85% and a constant temperature within the range 28 – 33°C. To evaluate the effectiveness of coatings protective action from moisture penetration into surface layers of sand moulds gravimetric method of quantitavie moisture sorption and ultrasonic method were applied in measurements.

  18. Locomotory transition from water to sand and its effects on undulatory kinematics in sand lances (Ammodytidae).

    Science.gov (United States)

    Gidmark, Nicholas J; Strother, James A; Horton, Jaquan M; Summers, Adam P; Brainerd, Elizabeth L

    2011-02-15

    Sand lances, fishes in the genus Ammodytes, exhibit a peculiar burrowing behavior in which they appear to swim rapidly into the substrate. They use posteriorly propagated undulations of the body to move in both water, a Newtonian fluid, and in sand, a non-Newtonian, granular substrate. In typical aquatic limbless locomotion, undulations of the body push against water, which flows because it is incapable of supporting the static stresses exerted by the animal, thus the undulations move in world space (slipping wave locomotion). In typical terrestrial limbless locomotion, these undulations push against substrate irregularities and move relatively little in world space (non-slipping wave locomotion). We used standard and X-ray video to determine the roles of slipping wave and non-slipping wave locomotion during burrowing in sand lances. We find that sand lances in water use slipping wave locomotion, similar to most aquatic undulators, but switch to non-slipping waves once they burrow. We identify a progression of three stages in the burrowing process: first, aquatic undulations similar to typical anguilliform locomotion (but without head yaw) push the head into the sand; second, more pronounced undulations of the aquatic portion of the body push most of the animal below ground; third, the remaining above-ground portion of the body ceases undulation and the subterranean portion takes over, transitioning to non-slipping wave locomotion. We find no evidence that sand lances use their body motions to fluidize the sand. Instead, as soon as enough of the body is underground, they undergo a kinematic shift and locomote like terrestrial limbless vertebrates.

  19. Effects of charged sand on electromagnetic wave propagation and its scattering field

    Institute of Scientific and Technical Information of China (English)

    HE; Qinshu; ZHOU; Youhe; ZHENG; Xiaojing

    2006-01-01

    Based on the Rayleigh's scattering theory, the effects of sandstorms on the propagation of electromagnetic wave with different visibilities are presented by solving the scattering field of charged sand particles. Because of the electric charges on the sand surface, the theoretical attenuation will be large enough to match the measured value under certain conditions. And the results show that the effect of sand with electric charges all over its surface on electromagnetic wave attenuation is the same as that of sand without charge, which proves that electric charges distribute on partial surface of the sand in fact.

  20. Small Strain Behaviour and Viscous Effects on Sands and Sand-Clay Mixtures

    Science.gov (United States)

    Di Benedetto, H.

    This lecture paper focuses on sands and sand-clay mixtures behaviour in the small strain domain. Non viscous and viscous components are measured, identified and modelled within the framework of a 3 component model. Two precision prototype devices (triaxial and hollow cylinder) both equipped with piezoelectric sensors are used. Non viscous measured behaviour considering small quasi-static cycles and wave properties are compared with simulations obtained from 2 recently formulated anisotropic hypoelastic models (DBGS and DBGSP). Then, viscous experimental part is compared with the proposed model prediction. This model is an asymptotic expression, for the small strain domain, of a viscous evanescent formalism proposed by the author. It takes into account very peculiar behaviour observed on sands. Simulation for loadings with and without rotation of axes and for different rate histories, are quite satisfactory.

  1. Effect of crushed sand on mortar and concrete rheology

    Directory of Open Access Journals (Sweden)

    Cabrera, O. A.

    2011-09-01

    Full Text Available This article describes an experimental study conducted on fresh mortars and concretes made with crushed sand. The aim of this research was to assess the effect of aggregate particle shape and surface texture as well as dust content on mortar and concrete rheology. The experimental programme also addressed the impact of angular grains on chemical admixture performance and concrete bleeding. The findings showed that the use of crushed sand induces rheological behaviour that differs from the behaviour observed in natural sand and that superplasticisers can improve this behaviour considerably.

    En el presente trabajo se plantea un estudio experimental del estado fresco de morteros y hormigones con arenas de machaqueo, orientado a la evaluación de la incidencia de la forma y textura superficial de los granos del árido fino y del contenido de polvo sobre la reología de las mezclas. El programa experimental comprendió el estudio del estado fresco de hormigones con arenas con partículas angulares, la influencia de este tipo de partículas sobre la efectividad de los aditivos químicos y la evaluación de la influencia de las características físicas del árido fino sobre la exudación. Los resultados muestran que el empleo de arenas de machaqueo provoca un comportamiento reológico diferente al de hormigones con arenas naturales, y que el efecto de los aditivos superfluidificantes mejora notablemente este comportamiento.

  2. Effect of surface-specific training on 20-m sprint performance on sand and grass surfaces.

    Science.gov (United States)

    Binnie, Martyn J; Peeling, Peter; Pinnington, Hugh; Landers, Grant; Dawson, Brian

    2013-12-01

    This study compared the effect of an 8-week preseason conditioning program conducted on a sand (SAND) or grass (GRASS) surface on 20-m sprint performance. Twelve team-sport athletes were required to attend three 1-hour training sessions per week, including 2 surface-specific sessions (SAND, n = 6 or GRASS, n = 6) and 1 group session (conducted on grass). Throughout the training period, 20-m sprint times of all athletes were recorded on both sand and grass surfaces at the end of weeks 1, 4, and 8. Results showed a significant improvement in 20-m sand time in the SAND group only (p grass time improved equally in both training subgroups (p grass speed gains when incorporating sand surfaces into a preseason program.

  3. Effective Laboratory Method of Chromite Content Estimation in Reclaimed Sands

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-09-01

    Full Text Available The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid. It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium. The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.

  4. The dune effect on sand-transporting winds on Mars

    Science.gov (United States)

    Jackson, Derek W. T.; Bourke, Mary C.; Smyth, Thomas A. G.

    2015-11-01

    Wind on Mars is a significant agent of contemporary surface change, yet the absence of in situ meteorological data hampers the understanding of surface-atmospheric interactions. Airflow models at length scales relevant to landform size now enable examination of conditions that might activate even small-scale bedforms (ripples) under certain contemporary wind regimes. Ripples have the potential to be used as modern `wind vanes' on Mars. Here we use 3D airflow modelling to demonstrate that local dune topography exerts a strong influence on wind speed and direction and that ripple movement likely reflects steered wind direction for certain dune ridge shapes. The poor correlation of dune orientation with effective sand-transporting winds suggests that large dunes may not be mobile under modelled wind scenarios. This work highlights the need to first model winds at high resolution before inferring regional wind patterns from ripple movement or dune orientations on the surface of Mars today.

  5. The dune effect on sand-transporting winds on Mars.

    Science.gov (United States)

    Jackson, Derek W T; Bourke, Mary C; Smyth, Thomas A G

    2015-11-05

    Wind on Mars is a significant agent of contemporary surface change, yet the absence of in situ meteorological data hampers the understanding of surface-atmospheric interactions. Airflow models at length scales relevant to landform size now enable examination of conditions that might activate even small-scale bedforms (ripples) under certain contemporary wind regimes. Ripples have the potential to be used as modern 'wind vanes' on Mars. Here we use 3D airflow modelling to demonstrate that local dune topography exerts a strong influence on wind speed and direction and that ripple movement likely reflects steered wind direction for certain dune ridge shapes. The poor correlation of dune orientation with effective sand-transporting winds suggests that large dunes may not be mobile under modelled wind scenarios. This work highlights the need to first model winds at high resolution before inferring regional wind patterns from ripple movement or dune orientations on the surface of Mars today.

  6. The dune effect on sand-transporting winds on Mars

    Science.gov (United States)

    Jackson, Derek W. T.; Bourke, Mary C; Smyth, Thomas A. G.

    2015-01-01

    Wind on Mars is a significant agent of contemporary surface change, yet the absence of in situ meteorological data hampers the understanding of surface–atmospheric interactions. Airflow models at length scales relevant to landform size now enable examination of conditions that might activate even small-scale bedforms (ripples) under certain contemporary wind regimes. Ripples have the potential to be used as modern ‘wind vanes' on Mars. Here we use 3D airflow modelling to demonstrate that local dune topography exerts a strong influence on wind speed and direction and that ripple movement likely reflects steered wind direction for certain dune ridge shapes. The poor correlation of dune orientation with effective sand-transporting winds suggests that large dunes may not be mobile under modelled wind scenarios. This work highlights the need to first model winds at high resolution before inferring regional wind patterns from ripple movement or dune orientations on the surface of Mars today. PMID:26537669

  7. Effect of Vibrational Modes on Sand Pressure and Pattern Deformation in the EPC Process

    Institute of Scientific and Technical Information of China (English)

    A.Ikenaga; G.S.Cho; K.H.Choe; K.W.Lee

    2004-01-01

    During the EPC (expendable pattern casting) process, one of the essential requirements is to prevent pattern distortion during sand filling and compaction. A new method which vibrates the system in a two-dimensional circular mode has been applied to the EPC process. The molding properties of unbonded sand obtained by this new vibration mode are investigated and compared with those in the one-dimensional vertical mode. For adequate compaction of sand, the circular vibration mode is more effective than the vertical mode. Sand became more fluidized by the circular vibration and the particle pressure coefficient was close to unity. The particle pressure coefficient, which is defined as the ratio of horizontal to vertical sand pressure, is responsible for the effectiveness of sand filling.

  8. Adverse effects of inhaled sand dust particles on the respiratory organs of sheep and goats exposed to severe sand storms in Mongolia.

    Science.gov (United States)

    Kobayashi, Yoshimi; Shimada, Akinori; Nemoto, Mai; Morita, Takehito; Adilbish, Altanchimeg; Bayasgalan, Mungun-Ochir

    2014-01-01

    Sand storms in Mongolia have increased in frequency and scale, resulting in increased exposure of the inhabitants of Asian countries, including Japan and Korea, to Asian sand dust (ASD), which results in adverse effects on the respiratory system. However, there is no information on the health risks of severe sand storms in domestic animals in Mongolia. The aim of the study was to investigate the effects of sand dust particles on the respiratory organs, including the lungs and tracheobronchial lymph nodes, of sheep and goats exposed to severe sand storms in Mongolia. Seven adult sheep and 4 adult goats that had been exposed to sand storms and 3 sheep with no history of exposure were included in this study. Lung tissues and tracheobronchial lymph nodes were subjected to histopathological and immunohistochemical examination. The mineralogical contents of the lungs and lymph nodes were determined using inductively coupled plasma atomic emission spectroscopy. Fibrosis and granulomatous lesions comprising macrophages containing fine sand dust particles were observed exclusively in the lungs of sheep and goats exposed to sand storms. The activity of macrophages was also demonstrated by the presence of IL-6, TNF, and lysozyme. In addition, silicon, which is the major element of ASD (kosa aerosol), was detected exclusively in the lung tissues of the exposed animals. Our findings suggest that exposure to sand dust particles may affect the respiratory systems of domestic animals during their relatively short life span.

  9. [Effect of concomitant substances and addition order on the adsorption of Tween 80 on sand].

    Science.gov (United States)

    Xu, Wei; Zhao, Yong-sheng; Li, Sui; Dai, Ning

    2008-08-01

    Adsorption of Tween 80 on sand was investigated, and the effect of inorganic salts (CaCl2), anionic surfactant (SDS) and lignosulphonates (sodium lignosulphonate or ammonium lignosulphonate) on the adsorption of Tween 80 on sand were evaluated at 25 degrees C. The results show that saturated adsorption amount of Tween 80 on sand enhance when CaCl2 or SDS is added into flushing solution of Tween 80. And the adsorption of Tween 80 on sand increase with the increase of molar fraction of CaCl2 or SDS in mixed flushing solution. And adsorption amount of Tween 80 on sand also enhance when SDS is added into sand firstly. The effects of mixing ratios and addition order of lignosulphonates on adsorption of Tween 80 were considered. The results show that with the increase of molar fraction of lignosulphonates in mixing flushing solution, adsorption amount of Tween 80 on sand decrease. The adsorption amount of Tween 80 reduce 20%-75% due to the exist of ammonium lignosulphonate is superior to sodium lignosulphonate (10%-60%) when mix the lignosulphonates-Tween 80 at the total mass ratios of 1:10, while the adsorption amount of Tween 80 reduce 70%-90% at the total mass ratios of 1:2. Lignosulphonates added into sand firstly is more efficient than that together. Therefore,use of lignosulphonates as a preflush can reduce the adsorption of surfactants on sand and is a better method to applied in in situ flushing.

  10. Aeolian sand transport and its effects on the stability of Miramar-Caranzalem beach

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, G.V.; Sastry, J.S.

    Removal of sand by wind from the beach at Miramar-Caranzalem, Goa, has been found to effect its stability over a relatively longer time scale. This aeolian sand transport has been computed for this strip of the beach utilising the relation between...

  11. Differential effects of a local industrial sand lance fishery on seabird breeding performance

    DEFF Research Database (Denmark)

    Frederiksen, M.; Jensen, Henrik; Daunt, F.;

    2008-01-01

    fluctuations. We evaluated the effects of an industrial sand lance (Ammodytes marinus) fishery off the North Sea coast of the United Kingdom, which has been opened and closed in a quasi-experimental fashion, on sand-lance-dependent breeding seabirds. Controlling for environmental variation ( sea surface...

  12. Effect of Fines on Liquefaction Resistance in Fine Sand and Silty Sand

    Directory of Open Access Journals (Sweden)

    Meraj Ahmad Khan

    2016-01-01

    Full Text Available It is required to recognize the conditions that exist in a soil deposit before an earthquake in order to identify liquefaction. Soil is basically an assemblage of many soil particles which stay in contact with many neighboring soil. The contact forces produced by the weight of the overlying particles holds individual soil particle in its place and provide strength. Occurrence of liquefaction is the result of rapid load application and break down of the loose and saturated sand and the loosely-packed individual soil particles tries to move into a denser configuration. However, there is not enough time for the pore-water of the soil to be squeezed out in case of earthquake. Instead, the water is trapped and prevents the soil particles from moving closer together. Thus, there is an increase in water pressure which reduces the contact forces between the individual soil particles causing softening and weakening of soil deposit. In extreme conditions, the soil particles may lose contact with each other due to the increased pore-water pressure. In such cases, the soil will have very little strength, and will behave more like a liquid than a solid - hence, the name "liquefaction".

  13. Filler effect of fine particle sand on the compressive strength of mortar

    Science.gov (United States)

    Jaturapitakkul, Chai; Tangpagasit, Jatuphon; Songmue, Sawang; Kiattikomol, Kraiwood

    2011-04-01

    The river sand, which is a non-pozzolanic material, was ground into 3 different particle sizes. Portland cement type I was replaced by the ground river sands at 10wt%-40wt% of binder to cast mortar. Compressive strengths of mortar were investigated and the filler effect of different fine particles of sand on the compressive strength of mortar was evaluated. The results show that the compressive strength of mortar contributed from the filler effect of smaller particles is higher than that of the coarser ones. The difference in compressive strength of mortar tends to be greater as the difference in ground river sand fineness increases. The results also suggest that ASTM C618 specification is not practically suitable for specifying pozzolan in concrete since the strength activity index of mortar containing ground river sand (high crystalline phase) with 33.8wt% of particles retained on a 45-μm sieve can pass the strength requirement.

  14. Sand effects on thermal barrier coatings for gas turbine engines

    Science.gov (United States)

    Walock, Michael; Barnett, Blake; Ghoshal, Anindya; Murugan, Muthuvel; Swab, Jeffrey; Pepi, Marc; Hopkins, David; Gazonas, George; Kerner, Kevin

    Accumulation and infiltration of molten/ semi-molten sand and subsequent formation of calcia-magnesia-alumina-silicate (CMAS) deposits in gas turbine engines continues to be a significant problem for aviation assets. This complex problem is compounded by the large variations in the composition, size, and topology of natural sands, gas generator turbine temperatures, thermal barrier coating properties, and the incoming particulate's momentum. In order to simplify the materials testing process, significant time and resources have been spent in the development of synthetic sand mixtures. However, there is debate whether these mixtures accurately mimic the damage observed in field-returned engines. With this study, we provide a direct comparison of CMAS deposits from both natural and synthetic sands. Using spray deposition techniques, 7% yttria-stabilized zirconia coatings are deposited onto bond-coated, Ni-superalloy discs. Each sample is coated with a sand slurry, either natural or synthetic, and exposed to a high temperature flame for 1 hour. Test samples are characterized before and after flame exposure. In addition, the test samples will be compared to field-returned equipment. This research was sponsored by the US Army Research Laboratory, and was accomplished under Cooperative Agreement # W911NF-12-2-0019.

  15. Effect of silty sand with different sizes on corrosion behavior of 3Cr steel in CO2 aqueous environment

    Science.gov (United States)

    Liu, Wei; Lu, Songle; Zhang, Peng; Dou, Juanjuan; Zhao, Qinghe

    2016-08-01

    Corrosion behavior of 3Cr steel in CO2 aqueous environment containing silty sand was investigated by immersion test. The results show that CO2 corrosion rate and morphology of 3Cr steel were obviously affected by the size of silty sand. 5000 mesh silty sand mixed with corrosion products, forming compact Cr-rich corrosion scale and resulting in low corrosion rate and uniform corrosion. 1000 mesh silty sand mixed with corrosion products, forming porous corrosion scale without Cr enrichment and resulting in high corrosion rate and pitting corrosion. 5000 mesh silty sand enhanced Cr enrichment in corrosion scale, leading to low anodic current. However, 1000 mesh silty sand deteriorated Cr enrichment in corrosion scale, leading to high anodic current. Cathodic current was reduced by silty sand, but was not affected by two sizes of silty sand. Cr enrichment in corrosion scale of 3Cr steel was obviously affected by separation effect of silty sand.

  16. Limited effectiveness of household sand filters for removal of arsenic from well water in North Vietnam.

    Science.gov (United States)

    Ilmiawati, Cimi; Thang, Nguyen Dinh; Iida, Machiko; Maeda, Masao; Ohnuma, Shoko; Yajima, Ichiro; Ohgami, Nobutaka; Oshino, Reina; Al Hossain, M M Aeorangajeb; Ninomiya, Hiromasa; Kato, Masashi

    2016-12-01

    Since well water utilized for domestic purposes in the Red River Delta of North Vietnam has been reported to be polluted by arsenic, barium, iron, and manganese, household sand filters consisting of various components are used. Information regarding the effectiveness of various sand filters for removal of the four toxic elements in well water is limited. In this study, arsenic levels in 13/20 of well water samples and 1/7 of tap water samples exceeded World Health Organization (WHO) health-based guideline value for drinking water. Moreover, 2/20, 6/20, and 4/20 of well water samples had levels exceeding the present and previous guideline levels for barium, iron, and manganese, respectively. Levels of iron and manganese, but not arsenic, in well water treated by sand filters were lower than those in untreated water, although previous studies showed that sand filters removed all of those elements from water. A low ratio of iron/arsenic in well water may not be sufficient for efficient removal of arsenic from household sand filters. The levels of barium in well water treated by sand filters, especially a filter composed of sand and charcoal, were significantly lower than those in untreated water. Thus, we demonstrated characteristics of sand filters in North Vietnam.

  17. Laboratory investigations of effective flow behavior in unsaturated heterogeneous sands

    DEFF Research Database (Denmark)

    Wildenschild, Dorthe; Høgh Jensen, Karsten

    1999-01-01

    such that on the average a uniform pressure profile was established and gravity flow applied. Solute breakthrough curves measured at discrete points in the tank using time domain reflectometry, as well as dye tracer paths, showed that flow and transport took place in a very tortuous pattern where several grid cells were...... controlled method. The heterogeneous sand systems were established in a laboratory tank for three realizations of random distributions of the homogeneous sands comprising a system of 207 grid cells. The water flux was controlled at the upper boundary, while a suction was applied at the lower boundary...

  18. Simulation of Effects of the Saffman Force and the Magnus Force on Sand Saltation in Turbulent Flow

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhongquan C.; Zou, Xueyong; Yang, Xiaofan; Cheng, Hong

    2011-12-11

    The effects of both the Saffman force and Magnus force on sand saltation are investigated. Turbulent flows in a channel and over a barchans dune are considered with sand particles injected into the flow. The results show that both of the forces increase the height and skipping distance of sand saltation, with the Magnus force giving more significant effect on the height. These forces can also increase the sand settling at the lee side of the barchans dune.

  19. Recent coastal dune development: Effects of sand nourishments

    NARCIS (Netherlands)

    Bakker, M.A.J.; Heteren, S. van; Vonhgen, L.M.; Spek, A.J.F. van der; Valk, B. van der

    2012-01-01

    Much of the Dutch coast has been subject to structural erosion. From 1990 onward, sand nourishments have been used under a government policy of dynamic preservation. Annual monitoring and field inspections show that the structural erosion has decreased or even turned into coastal progradation after

  20. EFFECTIVENESS OF THE SANDPITS SECURITY SYSTEM AGAINST MICROORGANISMS AND INTESTINAL PARASITES SAND CONTAMINATION

    Directory of Open Access Journals (Sweden)

    Magdalena Błaszak

    2015-09-01

    Full Text Available Playgrounds and sandpits (small architecture objects according to the Construction Law are subject to meticulous supervision, both at the design stage and subsequent status checks of the objects. One of the requirements arising from the need to protect playgrounds from animals is the necessity for fencing the object (Regulation of 31 December 2002 On Safety and Hygiene in Public and Private Schools and Institutions; Polish Standard PN-EN 1176 Playground equipment and surfacing. Does fencing playgrounds really reduce contamination of sand? To verify this hypothesis, the studies have been conducted on the residential areas’ sandpits, both fence secured and unsecured, located in close proximity to one another. The aim of the study was to evaluate the effectiveness of fences and nets as protection from microbial and parasite contamination of sandpits, mainly due to the access of animals to them. For several seasons of spring and summer the sand was examined in terms of the total number of heterotrophic bacteria and fungi (organic matter contamination of sand indicators and for the presence of coliform bacteria (including Escherichia coli, bacteria of the Salmonella genus and the eggs of intestinal parasites. It can be concluded that fencing playgrounds affects sand pollution less with waste and plant material (as a consequence, it has been reported statistically significantly less heterotrophic bacteria and fungi in the fenced sandpits’ sand. Unfortunately, the fence does not eliminate the risks associated with sand pollution of coliform bacteria. Cats and birds, but also dogs, still have a continuous access to sand. Due to the repeatedly stated carelessness of children and their caregivers, gates left open to the playground do not constitute an obstacle for domestic and stray animals. Another source of sand pollution with intestinal pathogens can be a manner of carriage of new sand, as there is no legislation governing the issue of transport

  1. Effects of sand burial on survival and growth of Artemisia halodendron and its physiological response

    Institute of Scientific and Technical Information of China (English)

    HaLin Zhao; Hao Qu; RuiLian Zhou; JianYing Yun; Jin Li

    2015-01-01

    There is a great deal of literature on the effects of sand burial upon the survival and growth of desert plants, but the physiological adaption mechanisms of desert plants to sand burial have as yet rarely been studied. Artemisia halodendron is widely distributed in the semi-arid deserts of China and is a dominant species in semi-moving dune vegetation. The growth and physiological properties of A. halodendron seedlings under different sand burial depths were studied in 2010 and 2011 in the Horqin Sand Land, Inner Mongolia, to better understand the ability and physiological mechanism by which desert plants withstand sand burial. The results showed that A. halodendron as a prammophyte species had a stronger ability to withstand sand burial compared to non-prammophytes, with some plants still surviving even if buried to a depth reaching 225% of seedling height. Although seedling growth was inhibited significantly once the depth of sand burial reached 50%of the seedling height, seedling survival did not decrease significantly until the burial depth exceeded 100%of the seedling height. Sand burial did not result in significant water stress or MDA (Malondialdehyde) accumulation in the seedlings, but membrane permeability increased significantly when the burial depth exceeded 100%of the seedling height. After being subjected to sand burial stress, POD (Peroxidase) activity and proline content increased significantly, but SOD (Superoxide Dismutase) and POD activities and soluble sugar content did not. The primary mechanism resulting in in-creased mortality and growth inhibition were that cell membranes were damaged and photosynthetic area decreased when subjected to the severe stress of sand burial, while proline and POD played key roles in osmotic adjustment and protecting cell membranes from damage, respectively.

  2. Unloading Characteristics of Sand-drift in Wind-shallow Areas along Railway and the Effect of Sand Removal by Force of Wind

    Science.gov (United States)

    Cheng, Jian-jun; Xin, Guo-Wei; Zhi, Ling-yan; Jiang, Fu-qiang

    2017-01-01

    Wind-shield walls decrease the velocity of wind-drift sand flow in transit. This results in sand accumulating in the wind-shadow zone of both windshield wall and track line, causing severe sand sediment hazard. This study reveals the characteristics of sand accumulation and the laws of wind-blown sand removal in the wind-shadow areas of three different types of windshield walls, utilizing three-dimensional numerical simulations and wind tunnel experiments and on-site sand sediment tests. The results revealed the formation of apparent vortex and acceleration zones on the leeward side of solid windshield walls. For uniform openings, the vortex area moved back and narrowed. When bottom-opening windshield walls were adopted, the track-supporting layer at the step became a conflux acceleration zone, forming a low velocity vortex zone near the track line. At high wind speeds, windshield walls with bottom-openings achieved improved sand dredging. Considering hydrodynamic mechanisms, the flow field structure on the leeward side of different types of windshield structures is a result of convergence and diffusion of fluids caused by an obstacle. This convergence and diffusion effect of air fluid is more apparent at high wind velocities, but not obvious at low wind velocities. PMID:28120915

  3. Unloading Characteristics of Sand-drift in Wind-shallow Areas along Railway and the Effect of Sand Removal by Force of Wind

    Science.gov (United States)

    Cheng, Jian-Jun; Xin, Guo-Wei; Zhi, Ling-Yan; Jiang, Fu-Qiang

    2017-01-01

    Wind-shield walls decrease the velocity of wind-drift sand flow in transit. This results in sand accumulating in the wind-shadow zone of both windshield wall and track line, causing severe sand sediment hazard. This study reveals the characteristics of sand accumulation and the laws of wind-blown sand removal in the wind-shadow areas of three different types of windshield walls, utilizing three-dimensional numerical simulations and wind tunnel experiments and on-site sand sediment tests. The results revealed the formation of apparent vortex and acceleration zones on the leeward side of solid windshield walls. For uniform openings, the vortex area moved back and narrowed. When bottom-opening windshield walls were adopted, the track-supporting layer at the step became a conflux acceleration zone, forming a low velocity vortex zone near the track line. At high wind speeds, windshield walls with bottom-openings achieved improved sand dredging. Considering hydrodynamic mechanisms, the flow field structure on the leeward side of different types of windshield structures is a result of convergence and diffusion of fluids caused by an obstacle. This convergence and diffusion effect of air fluid is more apparent at high wind velocities, but not obvious at low wind velocities.

  4. IMPROVEMENT OF EQUIPMENT FOR EFFECTIVE HARDENING SAND MIXTURE BY VACUUM MOLDING

    Directory of Open Access Journals (Sweden)

    V. S. Doroshenko

    2016-01-01

    Full Text Available The review deals with the design flask tooling and patterns for effective hardening sand mixture in the vacuum molding (V-Process, and molding on a one-off patterns (Lost Foam Casting. Sealing and evacuating sand mixture – two major factors influence the strength of the casting mold and casting quality, management practices which will enable to improve the casting process.

  5. Analysis of effectiveness of used sands reclamation treatment – in various technological devices

    Directory of Open Access Journals (Sweden)

    R. Dańko

    2009-10-01

    Full Text Available The analysis of effectiveness of spent sands reclamation treatment performed in technological devices of various intensity of dry reclamation – during which used binding material is being removed from grain surfaces – is presented in the paper. Variety of reclamation influences was considered via the realization of the so called elementary operations such as: rubbing, grinding and crushing [1-5], which are realised mainly in dry mechanical reclamation devices but also appear in other technological devices for sand preparation.The model rotor reclaimer and two types of mixers used for preparing initial foundry sands with resin U 404 and hardener 100 T3 of the Hüttenes-Albertus Company were applied for tests.The theoretical model for assessing the effectiveness of reclamation treatment developed by the author [3, 4], was experimentally verified [5, 7], with the application of standard testing procedures. The model can be considered a new tool enabling the selection of optimal reclamation times for the given used sand at the assumed intensity of silica sand matrix recovery. Sand mixture of a proper composition fulfilled needed technological properties after total hardening was used as charge material in experiments. The reclamation treatment consisted of mechanical and mechanical-cryogenic reclamation performed within a wide range of times and conditions influencing the treatment intensity.

  6. Colonization of Phlebotomus papatasi changes the effect of pre-immunization with saliva from lack of protection towards protection against experimental challenge with Leishmania major and saliva

    Directory of Open Access Journals (Sweden)

    Derbali Mohamed

    2011-07-01

    Full Text Available Abstract Background Sand fly saliva has been postulated as a potential vaccine or as a vaccine component within multi component vaccine against leishmaniasis. It is important to note that these studies were performed using long-term colonized Phlebotomus papatasi. The effect of sand flies colonization on the outcome of Leishmania infection is reported. Results While pre-immunization of mice with salivary gland homogenate (SGH of long-term colonized (F5 and beyond female Phlebotomus papatasi induced protection against Leishmania major co-inoculated with the same type of SGH, pre-immunization of mice with SGH of recently colonized (F2 and F3 female P. papatasi did not confer protection against L. major co-inoculated with the same type of SGH. Our data showed for the first time that a shift from lack of protection to protection occurs at the fourth generation (F4 during the colonization process of P. papatasi. Conclusion For the development of a sand fly saliva-based vaccine, inferences based on long-term colonized populations of sand flies should be treated with caution as colonization of P. papatasi appears to modulate the outcome of L. major infection from lack of protection to protection.

  7. Sand intake by laying hens and its effect on egg production parameters.

    Science.gov (United States)

    van der Meulen, J; Kwakernaak, C; Kan, C A

    2008-08-01

    Soil intake may be the most prominent source of environmental contaminants for free range and organic hens, but there are no quantitative data concerning soil intake by domestic hens. Consumption of soil of 14-32 g a day can be estimated from literature, but such a dilution of nutrient intake seems incompatible with high productivity. In this study laying hens were fed pelleted diets with 0%, 10%, 20%, 25% and 30% of sand addition to determine its effect on productivity. Feed intake, feed and nutrient (feed minus sand) conversion ratio, egg production, egg weight and body weight gain were measured over a 4-week period. Acid insoluble ash concentration in the faeces was measured to determine the accuracy of estimating the soil ingestion by the soil-ingestion equation for wildlife as a way to determine soil ingestion of free range and organic hens under practical circumstances. The hens were able to compensate the dilution of the diet with 20%, 25% and 30% of sand by increasing their feed intake. Feed intake increased significantly and feed to egg conversion ratio decreased significantly with increasing sand levels in the diet. The nutrient to egg conversion ratio of the diet without sand tended to be worse than for the diets with sand, presumably due to the total absence of coarse material in the diet. There were no differences in egg production and egg weight between hens fed the different diets but body weight gain was significantly lower for the hens fed the diets with 20%, 25% and 30% of sand. Estimation of sand ingestion was done by the soil-ingestion equation for wildlife. Provided that the actual dry matter digestibility coefficient of the nutrient part of the diet is taken into account, estimating the soil ingestion according to the soil-ingestion equation for wildlife seems an appropriate way to determine soil ingestion for free range and organic hens under practical circumstances.

  8. The Effect of the Kind of Sands and Additions on the Mechanical Behaviour of S.C.C

    Science.gov (United States)

    Zeghichi, L.; Benghazi, Z.; Baali, L.

    The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates. The effect of additions is also treated (blast furnace slag and lime stone) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

  9. LACK OF EFFECT OF CLONIDINE ON STUTTERING IN CHILDREN

    NARCIS (Netherlands)

    ALTHAUS, M; VINK, HJF; MINDERAA, RB; GOORHUISBROUWER, SM; OOSTERHOFF, MD

    1995-01-01

    Objective: The authors studied the effects of the alpha(2)-receptor agonist clonidine on stuttering in children. Method: Using a double-blind crossover study, they gave placebo or 4 mu g/kg body weight per day to 25 stuttering children who were 6-13 years old. Stuttering was measured by counting the

  10. LACK OF EFFECT OF CLONIDINE ON STUTTERING IN CHILDREN

    NARCIS (Netherlands)

    ALTHAUS, M; VINK, HJF; MINDERAA, RB; GOORHUISBROUWER, SM; OOSTERHOFF, MD

    Objective: The authors studied the effects of the alpha(2)-receptor agonist clonidine on stuttering in children. Method: Using a double-blind crossover study, they gave placebo or 4 mu g/kg body weight per day to 25 stuttering children who were 6-13 years old. Stuttering was measured by counting the

  11. LACK OF EFFECT OF CLONIDINE ON STUTTERING IN CHILDREN

    NARCIS (Netherlands)

    ALTHAUS, M; VINK, HJF; MINDERAA, RB; GOORHUISBROUWER, SM; OOSTERHOFF, MD

    1995-01-01

    Objective: The authors studied the effects of the alpha(2)-receptor agonist clonidine on stuttering in children. Method: Using a double-blind crossover study, they gave placebo or 4 mu g/kg body weight per day to 25 stuttering children who were 6-13 years old. Stuttering was measured by counting the

  12. Effects of woody vegetation on overbank sand transport during a large flood, Rio Puerco, New Mexico

    Science.gov (United States)

    Griffin, Eleanor R.; Perignon, Mariela C.; Friedman, Jonathan M.; Tucker, Gregory E.

    2014-01-01

    Distributions of woody vegetation on floodplain surfaces affect flood-flow erosion and deposition processes. A large flood along the lower Rio Puerco, New Mexico, in August 2006 caused extensive erosion in a reach that had been sprayed with herbicide in September 2003 for the purpose of saltcedar (Tamarix spp.) control. Large volumes of sediment, including a substantial fraction of sand, were delivered to the reach downstream, which had not been treated with herbicide. We applied physically based, one-dimensional models of flow and suspended-sediment transport to compute volume concentrations of sand in suspension in floodplain flow at a site within the sprayed reach and at a site downstream from the sprayed reach. We computed the effects of drag on woody stems in reducing the skin friction shear stress, velocity of flow, and suspended-sand transport from open paths into patches of dense stems. Total flow and suspended-sand fluxes were computed for each site using well-constrained flood-flow depths, water-surface slopes, and measured shrub characteristics. Results show that flow in open paths carried high concentrations of sand in suspension with nearly uniform vertical distributions. Drag on woody floodplain stems reduced skin friction shear stresses by two orders of magnitude, yet sufficient velocities were maintained to transport sand more than 50 m into fields of dense, free-surface-penetrating stems. An increase in shrub canopy extent from 31% in the sprayed reach site to 49% in the downstream site was found to account for 69% of the computed decrease in discharge between the two sites. The results demonstrate the need to compute the spatial distribution of skin friction shear stress in order to effectively compute suspended-sand transport and to predict the fate of sediment and contaminants carried in suspension during large floods.

  13. Blocking effect of colloids on arsenate adsorption during co-transport through saturated sand columns.

    Science.gov (United States)

    Ma, Jie; Guo, Huaming; Lei, Mei; Wan, Xiaoming; Zhang, Hanzhi; Feng, Xiaojuan; Wei, Rongfei; Tian, Liyan; Han, Xiaokun

    2016-06-01

    Transport of environmental pollutants through porous media is influenced by colloids. Co-transport of As(V) and soil colloids at different pH were systematically investigated by monitoring breakthrough curves (BTCs) in saturated sand columns. A solute transport model was applied to characterize transport and retention sites of As(V) in saturated sand in the presence of soil colloids. A colloid transport model and the DLVO theory were used to reveal the mechanism and hypothesis of soil colloid-promoted As(V) transport in the columns. Results showed that rapid transport of soil colloids, regulated by pH and ionic strength, promoted As(V) transport by blocking As(V) adsorption onto sand, although soil colloids had low adsorption for As(V). The promoted transport was more significant at higher concentrations of soil colloids (between 25 mg L(-1) and 150 mg L(-1)) due to greater blocking effect on As(V) adsorption onto the sand surfaces. The blocking effect of colloids was explained by the decreases in both instantaneous (equilibrium) As adsorption and first-order kinetic As adsorption on the sand surface sites. The discovery of this blocking effect improves our understanding of colloid-promoted As transport in saturated porous media, which provides new insights into role of colloids, especially colloids with low As adsorption capacity, in As transport and mobilization in soil-groundwater systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Effect of bentonite addition on residual strength of microwave-hardened waterglass-containing moulding sands

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2011-07-01

    Full Text Available The paper presents results of a preliminary research of the effect of bentonite addition on residual strength of microwave-hardened moulding sands, containing sodium waterglass. Strength was determined at ambient temperature, on cylindrical specimens baked in an oven. Moulding sands for examinations were based on high-silica sand with addition of 2.5 % of non-modified, domestic-made waterglass grade 145. The prepared standard cylindrical specimens were hardened using the innovative microwave heating process and next baked for 30 minutes at temperatures between 100 and 1200 °C. Strength parameters of the specimens were determined on the specimens cooled- down to ambient temperature. The obtained results were compared with literature data to evaluate the effect of the applied hardening method and of the special additive on residual strength as a function of baking temperature. A favourable effect was found of both the innovative heating process and the applied bentonite addition.

  15. Reduced effectiveness of selection caused by a lack of recombination.

    Science.gov (United States)

    Betancourt, Andrea J; Welch, John J; Charlesworth, Brian

    2009-04-28

    Genetic recombination associated with sexual reproduction is expected to have important consequences for the effectiveness of natural selection. These effects may be evident within genomes, in the form of contrasting patterns of molecular variation and evolution in regions with different levels of recombination. Previous work reveals patterns that are consistent with a benefit of recombination for adaptation at the level of protein sequence: both positive selection for adaptive variants and purifying selection against deleterious ones appear to be compromised in regions of low recombination [1-11]. Here, we re-examine these patterns by using polymorphism and divergence data from the Drosophila dot chromosome, which has a long history of reduced recombination. To avoid confounding selection and demographic effects, we collected these data from a species with an apparently stable demographic history, Drosophila americana. We find that D. americana dot loci show several signatures of ineffective purifying and positive selection, including an increase in the rate of protein evolution, an increase in protein polymorphism, and a reduction in the proportion of amino acid substitutions attributable to positive selection.

  16. Lack of effect of tenoxicam on glibornuride kinetics and response.

    Science.gov (United States)

    Stoeckel, K; Trueb, V; Dubach, U C; Heintz, R C; Ascalone, V; Forgo, I; Hennes, U

    1985-01-01

    The pharmacokinetics of glibornuride (25 mg i.v.) and the accompanying insulin and glucose responses were characterized in eight human subjects in the presence and absence of steady-state tenoxicam (20 mg p.o./day for 2 weeks). Tenoxicam affected neither the pharmacokinetic parameters of glibornuride (systemic clearance, volume of distribution and biological half-life) nor the responses of plasma insulin and blood glucose to glibornuride. The single i.v. dose of glibornuride had no detectable effect on the kinetics of tenoxicam. PMID:3157397

  17. Lack of immunomodulating effect of disulfiram on HIV positive patients

    DEFF Research Database (Denmark)

    Hørding, M; Gøtzsche, P C; Bygbjerg, Ib Christian;

    1990-01-01

    Disulfiram (Antabuse (R)) is metabolized to two molecules of diethyldithiocarbamate, which has been reported to be an immunomodulating agent. In a double blind trial, 15 HIV antibody positive homosexual men were given daily doses of 100 mg or 400 mg of disulfiram or placebo, for 4 weeks. All had...... a CD4-count below 500 X 10(6)/l and/or a pokeweed mitogen response in a lymphocyte proliferation assay less than 50% of normal controls. None suffered from opportunistic infections. No significant effect of disulfiram on immunological, haematological, biochemical or clinical variables was observed...

  18. Effects of fly ash on the properties of Silicafume concrete by using Robo sand

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Y.B.; Rafeeq, M. [Andhra Pradesh Engineering Research Lab., Hyderabad (India)

    2003-07-01

    The paper describes experiments to study the effects of fly ash from coal-fired power plants on the compressive and flexural strength, durability and permeability of typical high strength Silicafume concrete by using Robo sand (a synthetic sand). Tests results found there were improvements to some of the properties of the concrete when fly ash partly replaced Portland cement to an amount equal to 30% by mass of the cementitious materials. Fly ash enhances the workability of the Silicafume concrete but has a detrimental effect on its permeability. Further experiments are needed to obtain factual data for assessing design and economical consideration. 15 refs., 4 tabs.

  19. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  20. Effect of hardening method and structure of linking bridges on strength of water glass moulding sands

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2010-04-01

    Full Text Available The paper presents examination results of the effect of four hardening methods on structure of linking bridges in sandmixes containing hydrated sodium silicate. Test pieces prepared of the moulding sands containing 2.5 % of a binder with molar module between 2.4 and 2.6 were hardened with carbon dioxide, dried traditionally in an oven and hardened with microwaves at 2.54 GHz or using a combination of the CO2 process and microwave heating. It was revealed that the hardening method influences structure of linking bridges and is correlated with mechanical properties of the hardened moulding sands. It was found that strength of the moulding sands microwave-heated for 240 s is approximate to that measured after traditional drying for 120 min at 110 °C. So, the microwave hardening permits significant reduction of the process time, comparable to the CO2 hardening, at the same time guaranteeing over 10 times higher mechanical properties. Analysis of SEM photographs of the moulding sands hardened with the mentioned methods allow explaining differences in qualitative parameters of the moulding sands and their relation to structures of the created linking bridges.

  1. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  2. The effect of sand storms on acute asthma in Riyadh, Saudi Arabia.

    Science.gov (United States)

    Alangari, Abdullah A; Riaz, Muhammad; Mahjoub, Mohamed Osman; Malhis, Nidal; Al-Tamimi, Saleh; Al-Modaihsh, Abdullah

    2015-01-01

    Major sand storms are frequent in the Middle East. This study aims to investigate the role of air particulate matter (PM) level in acute asthma in children in Riyadh, Saudi Arabia. An aerosol spectrometer was used to evaluate PM 1000 μg/m(3), representing major sand storms, plus the following 5 days and other days with PM10storms, even major ones, had no significant impact on acute asthma exacerbations in children in Riyadh, Saudi Arabia. The very high levels of PM, however, deserve further studying especially of their long-term effects.

  3. Study of Sand Dunes and Their Effect on Desertification of Cultivated Lands in Shaanxi Province, China Using Remote Sensing Techniques

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    About half of the arid and semi-arid lands in the world are deserts that comprise various types of aeolian sand dunes deposits. In Shaanxi Province, aeolian sand dunes cover considerable areas of the Yulin desert and northern Jinbian. Sand dunes are moving in the main wind direction and converting some agricultural area to wasteland. Remote sensing of sand dunes helps in the understanding of aeolian process and desertification. Remote sensing data combined with field studies are valuable in studying sand dunes, regional aeolian depositional history. In particular, active and inactive sand dunes of the north Shaanxi Province were studied using remote sensing and geographic information system. In this study, we describe the Landsat thematic mapper (TM) images, covering north Shaanxi Province, which were used to study the distribution, shape, size, trends, density and movement of sand dunes and their effect on desertification of cultivated lands. Estimation was made depending on soil erodibility factor (Ⅰ) and local climatic factor (C) during the period (June to September). The result indicates that soil erosion caused sand drift of 8.957 5, 7.03 ton for Yulin and Jinbian, respectively. The mean sand dunes movement rate were 4.37, 3.11 m, whereas, monthly sand dune advance rate were 1.092 5, 0.777 5 m, for the two locations, respectively. The study reveals that cultivated lands extended obliquely to the direction of sand dune movement are extremely affected, while other segments that extend parallel to the direction of the movement are not affected. Accordingly the north Shaanxi Province was divided into areas of different classes of potential risk. Moreover, blown sands and sand movement from neighboring highlands also affect the area of western desert.

  4. Experimental Investigation of the Effect of Manufactured Sand and Lightweight Sand on the Properties of Fresh and Hardened Self-Compacting Lightweight Concretes

    Directory of Open Access Journals (Sweden)

    Yiyun Zhu

    2016-08-01

    Full Text Available Self-compacting lightweight concrete (SCLC is a promising construction material for building applications, but most SCLCs today are made with river sand (RS. There is an increasing demand for environmental protection, as well as materials with a high strength/density ratio. The manufactured sand (MS and lightweight sand (LS as fine aggregates in cement-based composite materials have been receiving more attention among researchers. However, there is not much information about the effects of MS and LS on the properties of the fresh and hardened SCLCs. In this paper, the properties of fresh and hardened SCLC made with MS and LS were investigated by a series of experiments. SCLCs made with RS served as the control in this study. The test results show that increasing the sand ratio (from 0.40–0.50 decreased the filling ability and led to an increased T50 time, which is the time spent for the concrete to reach the 500 mm spread circle, for all of the fresh SCLCs. Although the passing ability of MS-SCLCs and LS-SCLCs is not as good as RS-SCLCs, their results are still within an acceptable range. The ratio of mechanical properties to density was found to increase with an increase of the sand ratio for all of the hardened SCLCs. MS-SCLCs presented the highest compressive strength among all of the SCLCs studied. Although the mean compressive strength of LS-SCLCs is lower than those of the other two SCLCs by 8%, their strength to density ratio is higher than others by 15%, and the ratio increases remarkably with the increase of the sand ratio. Permeability test results showed that the permeability coefficient of MS-SCLC is remarkably lower than that of LS-SCLC, but slightly higher than that of RS-SCLC.

  5. 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...

  6. Effect of Shale Distribution on Hydrocarbon Sands Integrated with Anisotropic Rock Physics for AVA Modelling: A Case Study

    Science.gov (United States)

    Ali, Aamir; Zubair; Hussain, Matloob; Rehman, Khaista; Toqeer, Muhammad

    2016-08-01

    Shales can be distributed in sand through four different ways; laminated, structural, dispersed and any combination of these aforementioned styles. A careful analysis of well log data is required for the determination of shale distribution in sand affecting its reservoir quality. The objective of this study is to characterize the effect of shale distribution on reservoir quality of sands using well log data. The correlation of well data in terms of lithology has revealed four sand and three shale layers in Lower Goru Formation acting as a major reservoir in the study area. Our results indicate that the laminated type of shale distribution prevails at the Basal sand level, which does not affect its reservoir quality greatly. The remaining layers of variable vertical extent show a variety of shale distribution models affecting their reservoir quality adversely. We also present anisotropic rock physics modelling for AVA analysis at Basal sand level.

  7. Effects Of Evaporation Rate of Some Common Organic Contaminants on Hydraulic Conductivity of Aquifer Sand

    Science.gov (United States)

    Saud, Q. J.; Hasan, S. E.

    2014-12-01

    As part of a larger study to investigate potential effects of hydrocarbons on the geotechnical properties of aquifer solids, a series of laboratory experiments were carried out to ascertain the influence of evaporation rate of some common and widespread organic contaminants on the hydraulic conductivity of aquifer sand. Gasoline and its constituent chemicals-benzene, toluene, ethylbenzene, xylene (BTEX), isooctane- and trichloroethylene (TCE) were used to contaminate sand samples collected from the aquifer and vadose zone, at varying concentrations for extended periods of time. The goal was to study any change in the chemical makeup of the contaminants and its control on hydraulic conductivity of the sand. It was found that: (a) gasoline breaks down into constituent compounds when subjected to evaporation, e.g. during oil spills and leaks; and (b) lighter compounds volatilize faster and in the following order: TCE> benzene > isooctane > toluene > gasoline> ethylbenzene > xylene. In addition, these contaminants also caused a decrease in hydraulic conductivity of sand by up to 60% as compared to the uncontaminated sand. The inherent differences in the chemical structure of contaminating chemicals influenced hydraulic conductivity such that the observed decrease was greater for aliphatic than aromatic and chlorinated hydrocarbons. The presentation includes details of the experimental set up; evaporation rate, and geotechnical tests; X-ray diffraction and scanning electron microscope studies; and data analyses and interpretation. Rate of evaporation test indicates that residual LNAPLs will occupy a certain portion of the pores in the soil either as liquid or vapor phase in the vadose zone, and will create a coating on the adjacent solid mineral grains in the aquifer. Replacement of air by the LNAPLs along with grain coatings and the intramolecular forces would impede groundwater movement, thus affecting overall permeability of contaminated aquifers. Keywords: aquifer

  8. Sand Dune Ridge Alignment Effects on Surface BRF over the Libya-4 CEOS Calibration Site

    Directory of Open Access Journals (Sweden)

    Yves M. Govaerts

    2015-02-01

    Full Text Available The Libya-4 desert area, located in the Great Sand Sea, is one of the most important bright desert CEOS pseudo-invariant calibration sites by its size and radiometric stability. This site is intensively used for radiometer drift monitoring, sensor intercalibration and as an absolute calibration reference based on simulated radiances traceable to the SI standard. The Libya-4 morphology is composed of oriented sand dunes shaped by dominant winds. The effects of sand dune spatial organization on the surface bidirectional reflectance factor is analyzed in this paper using Raytran, a 3D radiative transfer model. The topography is characterized with the 30 m resolution ASTER digital elevation model. Four different regions-of-interest sizes, ranging from 10 km up to 100 km, are analyzed. Results show that sand dunes generate more backscattering than forward scattering at the surface. The mean surface reflectance averaged over different viewing and illumination angles is pretty much independent of the size of the selected area, though the standard deviation differs. Sun azimuth position has an effect on the surface reflectance field, which is more pronounced for high Sun zenith angles. Such 3D azimuthal effects should be taken into account to decrease the simulated radiance uncertainty over Libya-4 below 3% for wavelengths larger than 600 nm.

  9. Sand dune ridge alignment effects on surface BRF over the Libya-4 CEOS calibration site.

    Science.gov (United States)

    Govaerts, Yves M

    2015-02-03

    The Libya-4 desert area, located in the Great Sand Sea, is one of the most important bright desert CEOS pseudo-invariant calibration sites by its size and radiometric stability. This site is intensively used for radiometer drift monitoring, sensor intercalibration and as an absolute calibration reference based on simulated radiances traceable to the SI standard. The Libya-4 morphology is composed of oriented sand dunes shaped by dominant winds. The effects of sand dune spatial organization on the surface bidirectional reflectance factor is analyzed in this paper using Raytran, a 3D radiative transfer model. The topography is characterized with the 30 m resolution ASTER digital elevation model. Four different regions-of-interest sizes, ranging from 10 km up to 100 km, are analyzed. Results show that sand dunes generate more backscattering than forward scattering at the surface. The mean surface reflectance averaged over different viewing and illumination angles is pretty much independent of the size of the selected area, though the standard deviation differs. Sun azimuth position has an effect on the surface reflectance field, which is more pronounced for high Sun zenith angles. Such 3D azimuthal effects should be taken into account to decrease the simulated radiance uncertainty over Libya-4 below 3% for wavelengths larger than 600 nm.

  10. Metal bioaccumulation and biomarkers of effects in caged mussels exposed in the Athabasca oil sands area.

    Science.gov (United States)

    Pilote, M; André, C; Turcotte, P; Gagné, F; Gagnon, C

    2017-08-11

    The Athabasca oil sands deposit is the world's largest known reservoir of crude bitumen and the third-largest proven crude oil reserve. Mining activity is known to release contaminants, including metals, and to potentially impact the aquatic environment. The purpose of this study was to determine the impacts of oil sands mining on water quality and metal bioaccumulation in mussels from the Fort McMurray area in northern Alberta, Canada. The study presents two consecutive years of contrasting mussel exposure conditions (low and high flows). Native freshwater mussels (Pyganodon grandis) were placed in cages and exposed in situ in the Athabasca River for four weeks. Metals and inorganic elements were then analyzed in water and in mussel gills and digestive glands to evaluate bioaccumulation, estimate the bioconcentration factor (BCF), and determine the effects of exposure by measuring stress biomarkers. This study shows a potential environmental risk to aquatic life from metal exposure associated with oil sands development along with the release of wastewater from a municipal treatment plant nearby. Increased bioaccumulation of Be, V, Ni and Pb was observed in mussel digestive glands in the Steepbank River, which flows directly through the oil sands mining area. Increased bioaccumulation of Al, V, Cr, Co, Ni, Mo and Ni was also observed in mussel gills from the Steepbank River. These metals are naturally present in oil sands and generally concentrate and increase with the extraction process. The results also showed different pathways of exposure (particulate or dissolved forms) for V and Ni resulting from different river water flows, distribution coefficient (Kd) and BCF. Increasing metal exposure downstream of the oil sands mining area had an impact on metallothionein and lipid peroxidation in mussels, posing a potential environmental risk to aquatic life. These results confirm the bioavailability of some metals in mussel tissues associated with detoxification of

  11. The effect of temperature on Leishmania (Kinetoplastida: Trypanosomatidae) development in sand flies.

    Science.gov (United States)

    Hlavacova, J; Votypka, J; Volf, P

    2013-09-01

    The spread of leishmaniasis to areas where it was previously considered nonendemic has been recently found in the New and Old Worlds, and climate changes are suspected as a crucial factor responsible for this spread. Ambient temperature is known to significantly affect the metabolism of sand flies and their developmental times, but little is known about the effect of temperature on the Leishmania life cycle in vectors. This study assesses the effect of temperature on the development of two closely related New World Viannia species, Leishmania braziliensis and Leishmania peruviana, in the permissive vector Lutzomyia longipalpis, and on the development of New and Old World Leishmania infantum in its natural vectors Lu. longipalpis and Phlebotomus perniciosus, respectively. The mountain species L. peruviana developed well in sand fly females kept at 20 degrees C, whereas at 26 degrees C, most infections were lost during the defecation ofbloodmeal remains; this suggests an adaptation to the slower metabolism of sand flies living at lower ambient temperature. On the contrary, L. infantum and L. braziliensis developed well at both temperatures tested; heavy late-stage infections were observed in a majority of sand fly females maintained at 20 degrees C as well 26 degrees C. Frequent fully developed infections of L. infantum and L. braziliensis at 20 degrees C suggest a certain risk of the spread of these two Leishmania species to higher latitudes and altitudes.

  12. The effect of oil sands tailings pond sediments on embryo-larval walleye (Sander vitreus).

    Science.gov (United States)

    Raine, J C; Turcotte, D; Tumber, V; Peru, K M; Wang, Z; Yang, C; Headley, J V; Parrott, J L

    2017-10-01

    Walleye (Sander vitreus) are a commercially important North American fish species that inhabit the Athabasca River. This river flows through the Athabasca oil sands where natural sources of bitumen erode from the McMurray formation. Little information is available on responses of walleye embryos to oil sands tailings pond sediments in a laboratory setting. The current study describes the design and implementation of a daily-renewal bioassay to assess the potential effects of tailings pond sediments from the Athabasca oil sands area on walleye development. Developing walleye embryos were exposed to increasing concentrations of two tailings pond sediments (collected in the Athabasca oil sands area) until the completion of yolk absorption in control fish. Sediments from the tailings pond represent a mixture of polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs. During the 31 day exposure, the walleye were examined for mortalities, weight, length and developmental abnormalities to provide an initial evaluation of the effects of the oil sands tailings pond sediments. Walleye embryo survival differed between the tailings pond sediments, and survival decreased with increasing sediment concentration. Alkylated PAH content differed between the two tailings pond sediments and lower embryo survival corresponded to higher total and alkylated PAH content. Tailings pond sediment-exposed walleye exhibited a delay in development, as well as increased percentages of larvae with heart and yolk sac edema, and cranial and spinal malformations. These abnormalities in development are often associated with PAH and alkylated PAH exposure. This study provides an exposure design that can be used to assess sediment toxicity to early developmental stages of a fish species not commonly tested in the lab, and lays the groundwork for future studies with this and other difficult-to-culture species. These results offer information on the potential effects of tailings pond sediments

  13. Slow sand filters effectively reduce Phytophthora after a pathogen switch from Fusarium and a simulated pump failure.

    Science.gov (United States)

    Lee, Eric; Oki, Lorence R

    2013-09-15

    Slow sand filtration has been shown to effectively reduce Phytophthora zoospores in irrigation water. This experiment tested the reduction of Phytophthora colony forming units (CFUs) by slow sand filtration systems after switching the pathogen contaminating plant leachate from Fusarium to Phytophthora and the resilience of the system to a short period without water, as might be caused by a pump failure. The slow sand filtration system greatly reduced Phytophthora CFUs and transmission after switching the pathogens. In addition, Phytophthora reduction by the slow sand filter was equally effective before and after the simulated pump failure. Reduction of Fusarium was not seen by the SSFs, before or after the simulated pump failure. The results suggest that slow sand filters are effective at reducing larger organisms, such as Phytophthora zoospores, even after a pump failure or a change in pathogens.

  14. Sand-fixing effects of Caragana microphylla shrub in Horqin sandy land, North China

    Institute of Scientific and Technical Information of China (English)

    Shanfeng HE; Lanlan QIU; Deming JIANG; Lamusa A; Zhimin LIU; Yongming LUO

    2008-01-01

    In the semi-arid Horqin sandy land of north China,Caragana microphylla, a leguminous shrub, is the dominant plant species and is widely used in vegetation reestablishment programs to stabilize shifting sand. The sand-fixing effects of 6- and 11-year-old C. Microphylla plantations were studied. The results showed that: 1) the wind velocity and sand transport rate in the plantation were less than those in dunes;2) the air temperature in the plantation was lower than those in dunes. Relative humidity was higher and the soil temperature was lower, which benefits plant growth; 3) the physical and chemical characteristics of soil were improved to some extent over age. The porosity and percentage of tiny sand (diameter 0.05-0.1 mm) and clay particle (diameter<0.05 mm) increased,bulk density in surface soil decreased, and saturated water-holding capacity improved. Organic C, total N, available N and available K content increased gradually, and soil fertility was enhanced.

  15. Effect of Epoxy Resin Mixtures on the Physical and Mechanical Properties of Sand

    Directory of Open Access Journals (Sweden)

    Costas A. Anagnostopoulos

    2014-05-01

    Full Text Available The use of new materials for soil strengthening is crucial for geotechnical engineering, especially in foundation construction. The main objective of this study was to investigate the potential use of two-component water-soluble epoxy resin to improve the physical and mechanical properties of medium sand, because the efficacy of these resins on soil strengthening has not yet been properly investigated. The experiments were conducted using resins with different epoxy resin-to-water ratios. The results of this study indicate that the epoxy resins improve the physical and mechanical properties of the sand significantly and if successfully grouted into a formation, the resins could provide a suitable solution for the stabilization of the foundation material. In separate experiments, electro osmotic treatment of sand/resin mixtures was conducted with the aim of identifying the effectiveness of electro kinetic method on the early strength development of sand/resin mixtures. From the results it was observed that the electroosmotically treated specimens appeared to have much greater strength enhancement than the one of the untreated specimens.

  16. The Effect of Soil Particle Arrangement on Shear Strength Behavior of Silty Sand

    Directory of Open Access Journals (Sweden)

    Nik Norsyahariati Nik Daud

    2016-01-01

    Full Text Available The presence of fines in sandy soil is recognized as a problem in geotechnical engineering. It is often assumed that the strength and liquefaction potential of a soil decreases with increasing fines content. Sand with a significant amount of fines is always encountered in geotechnical engineering projects. The main interest of this paper is to study the effect of particles arrangement and stress behaviour on sand and silty sand sample. The objectives are to determine the basic properties as well as the morphological and mineralogical properties and the relationship of those properties to the stress behaviour of the soils. Sand-silt mixtures with fines contents of 20% and 40% were prepared and a series of testing was carried out to determine their basic properties, morphological and thin section properties, and mechanical properties by using direct shear box equipment. Results show that the basic properties and morphological properties of soil affect the mechanical behaviour of soil. Shape of the soil particle can influence the packing of the soil, hence altering the mechanical behaviour of the soil. From the thin section, the soil is observed to be well graded and have a dense packing while the minerals observed were mainly quartz and rutile.

  17. How extensive is the effect of modern farming on bird communities in a sand dune desert?

    Directory of Open Access Journals (Sweden)

    Faris Khoury

    2009-12-01

    Full Text Available Bird community structure and diversity measures in sand dune habitats far from and close to modern farms in Wadi Araba, south-west Jordan, were compared using 52 line transects for breeding birds and habitat variables. A change in the bird community of sand dunes surrounding farming projects was measured to a distance of 1 km, but could neither be related to changes in habitat structure nor to the activity of op- portunistic predators (Red Fox as these did not vary significantly between the two samples. The farms included lines of trees and offered a constant source of water, which attracted a variety of opportunistic species, thus increasing bird diversity and total bird abundances. The absence of characteristic ground-dwelling species of open sand dune habitats in the structurally intact sand dunes surrounding farms was likely to be the result of localized, but effectively far-reaching habitat modification (farms acting as barriers and/or competition with some of the opportunistic species, which were common around farms.

  18. Effect of different-sized colloids on the transport and deposition of titanium dioxide nanoparticles in quartz sand.

    Science.gov (United States)

    Cai, Li; Peng, Shengnan; Wu, Dan; Tong, Meiping

    2016-01-01

    Colloids (non-biological and biological) with different sizes are ubiquitous in natural environment. The investigations regarding the influence of different-sized colloids on the transport and deposition behaviors of engineered-nanoparticles in porous media yet are still largely lacking. This study investigated the effects of different-sized non-biological and biological colloids on the transport of titanium dioxide nanoparticles (nTiO2) in quartz sand under both electrostatically favorable and unfavorable conditions. Fluorescent carboxylate-modified polystyrene latex microspheres (CML) with sizes of 0.2-2 μm were utilized as model non-biological colloids, while Gram-negative Escherichia coli (∼ 1 μm) and Gram-positive Bacillus subtilis (∼ 2 μm) were employed as model biological colloids. Under the examined solution conditions, both breakthrough curves and retained profiles of nTiO2 with different-sized CML particles/bacteria were similar as those without colloids under favorable conditions, indicating that the copresence of model colloids in suspensions had negligible effects on the transport and deposition of nTiO2 under favorable conditions. In contrast, higher breakthrough curves and lower retained profiles of nTiO2 with CML particles/bacteria relative to those without copresent colloids were observed under unfavorable conditions. Clearly, the copresence of model colloids increased the transport and decreased the deposition of nTiO2 in quartz sand under unfavorable conditions (solution conditions examined in present study). Both competition of deposition sites on quartz sand surfaces and the enhanced stability/dispersion of nTiO2 induced by copresent colloids were found to be responsible for the increased nTiO2 transport with colloids under unfavorable conditions. Moreover, the smallest colloids had the highest coverage on sand surface and most significant dispersion effect on nTiO2, resulting in the greatest nTiO2 transport. Copyright © 2015. Published

  19. Effect of carbon nanotubes on properties of cement-sand-based piezoelectric composites

    Science.gov (United States)

    Kim, Sunjung; Zhao, Ping; Enemuoh, Emmanuel

    2015-04-01

    Carbon Nanotubes (CNTs) were dispersed in a cement-sand-based piezoelectric smart composite as conductive fillers to improve its poling efficiency, leading to a desirable piezoelectric effect. By introducing a small amount of CNTs, continuous electric networks between Lead Zirconate Titanate (PZT) particles were created, thus making the composite poling easier. Specimens were prepared by mixing PZT powders, Portland cement and sand with CNTs, followed by pressing it with a load frame system. The effect of quantity of CNTs ranging from 0 to 1.0 volume percent on properties of the composite, including its piezoelectric coefficient, dielectric constant and loss, and sensing effects, were characterized. It was found that the addition of CNTs facilitated effective poling at room temperature and improved the piezoelectric and dielectric properties of the composite. The composite modified by CNTs achieved optimal properties when the CNTs content was 0.7 vol.%.

  20. Dynamics of sand ridges in coastal seas: the effect of storms, tides and grain sorting

    Science.gov (United States)

    Walgreen, M.

    2003-10-01

    The work presented in this thesis concerns the dynamics of shoreface-connected ridges and tidal sand ridges. These large-scale bedforms are observed on the inner and outer shelf of coastal seas in water depths of 10-20m. The motivation of this work is to improve the understanding of the mechanisms related to their formation and the processes that determine their main characteristics. This is done with the use of idealised morphodynamic models. The basic assumption underlying these models is that large-scale sand ridges can solely form as free instabilities on a flat sea bottom. Mathematical methods based on a stability analysis are applied, whereas analytical and numerical methods are used to solve the equations. Existing models are extended with new physical processes, in particular including the role of grain sorting. An important part of this thesis concerns the unresolved question about the origin of the observed mean grain size pattern over the ridges. It explores the hydrodynamic processes that can lead to sediment sorting and the formation of large-scale sand ridges. The model results indicate that the dynamics for different forcing conditions strongly differ. Shoreface-connected sand ridges mainly form during storm conditions, whereas if fair weather conditions prevail the more offshore located tidal sand ridges develop. A probabilistic formulation of these two realisation of the model is used to find conditions for which both types of large-scale bedforms occur simultaneously, as is the case in the southern North Sea. These conditions turn out to be a low storm fraction and the presence of both tidal and storm-driven currents. The transport of non-uniform sediment is described by formulations for both bed load and suspended load, both of which account for dynamic hiding effects. A one-layer model for the bed evolution is used and two grain size classes (fine and coarse sand) are considered. The results of the model for storm conditions indicate that the

  1. Effect of upstream fencing on shelter zone behind solid models simulating sand formations and dunes

    Directory of Open Access Journals (Sweden)

    Mahmoud A. Hassan

    2013-04-01

    Moreover, results indicate that some dune/fence combinations may cause shifting of the dune upwind (instead of downwind in the absence of fence. This effect means that, with such combinations, a dune would eventually disappear. The distance between the model downwind base line and the location of reattachment (length of shelter zone was plotted against the distance of fence from upwind base line of model to determine the best possible dune/fence combination. Solid fencing (constructed from masonry bricks or stones to shelter isolated sand humps and dunes is effective in alleviating dangers on nearby structures (dune shifting upwind and to less sand drift and saltation downwind. Also, the results indicated that, it is recommended to start by dune fencing and give enough time for the project zone to widen and be effectively protected before starting the construction.

  2. Effect of walking on sand on gait kinematics in individuals with multiple sclerosis.

    Science.gov (United States)

    van den Berg, Maayken E L; Barr, Christopher J; McLoughlin, James V; Crotty, Maria

    2017-08-01

    Walking in the real-world involves negotiating challenging or uneven surfaces, including sand. This can be challenging for people with Multiple Sclerosis (PWMS) due to motor deficits affecting the lower extremities. The study objective was to characterise kinematic gait adaptations made by PWMS when walking on sand and describe any immediate post-adaptation effects. 17 PWMS (mean age 51.4 ± 5.5, Disease Steps 2.4 ± 1.0), and 14 age-and gender matched healthy adults (HA) took part in a case-control study. 3D gait analysis was conducted using an eight-camera Vicon motion capture system. Each participant completed walking trials over level ground (baseline), sand (gait adaptation response), and again level ground (post-adaptation). Spatiotemporal data and kinematic data for the hip knee and ankle were recorded. At baseline PWMS showed significantly less total lower limb flexion (p<0.05) compared to HA. PWMS adapted to walking on sand by significantly increasing hip and knee flexion and ankle dorsiflexion (p<0.05) during swing, resulting in an overall 23° greater total lower limb flexion (p<0.05), reaching values within normal range. During the return to level ground walking values of temporal-spatial and kinematic parameters returned towards baseline values. PWMS adapted to walking on sand by increasing lower limb flexion during swing, and returned to their gait pattern to near baseline levels, in a manner similar to but with values not equalling HA. Further work is required to determine whether this mode of walking has potential to act as a gait retraining strategy to increase flexion of the lower limb. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Effects of Sand Dune Stabilization on the Spatial Pattern of Artemisia ordosica Population in Mu Us Desert, Northwest China.

    Science.gov (United States)

    Zhang, Jiachen; Zhang, Yuqing; Fan, Dongqing; Qin, Shugao; Jia, Xin; Wu, Bin; Chen, Dong; Gao, Hao; Zhu, Linfeng

    2015-01-01

    Vegetation patterns are strongly influenced by sand mobility in desert ecosystems. However, little is known about the spatial patterns of Artemisia ordosica, a dominant shrub in the Mu Us desert of Northwest China, in relation to sand fixation. The aim of this study was to investigate and contrast the effects of sand dune stabilization on the population and spatial distribution of this desert shrub. Spatial autocorrelation, semi-variance analysis, and point-pattern analysis were used jointly in this study to investigate the spatial patterns of A. ordosica populations on dunes in Yanchi County of Ningxia, China. The results showed that the spatial autocorrelation and spatial heterogeneity declined gradually, and the distance between the clustered individuals shortened following sand dune fixation. Seedlings were more aggregated than adults in all stage of dune stabilization, and both were more aggregated on shifting sand dunes separately. Spatial associations of the seedlings with the adults were mostly positive at distances of 0-5 m in shifting sand dunes, and the spatial association changed from positive to neutral in semi-fixed sand dunes. The seedlings were spaced in an almost random pattern around the adults, and their distances from the adults did not seem to affect their locations in semi-fixed sand dunes. Furthermore, spatial associations of the seedlings with the adults were negative in the fixed sand dune. These findings demonstrate that sand stabilization is an important factor affecting the spatial patterns of A. ordosica populations in the Mu Us desert. These findings suggest that, strong association between individuals may be the mechanism to explain the spatial pattern formation at preliminary stage of dune fixation. Sand dune stabilization can change the spatial pattern of shrub population by weakening the spatial association between native shrub individuals, which may affect the development direction of desert shrubs.

  4. Arsenic removal from drinking water by a household sand filter in Vietnam--effect of filter usage practices on arsenic removal efficiency and microbiological water quality.

    Science.gov (United States)

    Nitzsche, Katja Sonja; Lan, Vi Mai; Trang, Pham Thi Kim; Viet, Pham Hung; Berg, Michael; Voegelin, Andreas; Planer-Friedrich, Britta; Zahoransky, Jan; Müller, Stefanie-Katharina; Byrne, James Martin; Schröder, Christian; Behrens, Sebastian; Kappler, Andreas

    2015-01-01

    Household sand filters are applied to treat arsenic- and iron-containing anoxic groundwater that is used as drinking water in rural areas of North Vietnam. These filters immobilize poisonous arsenic (As) via co-oxidation with Fe(II) and sorption to or co-precipitation with the formed Fe(III) (oxyhydr)oxides. However, information is lacking regarding the effect of the frequency and duration of filter use as well as of filter sand replacement on the residual As concentrations in the filtered water and on the presence of potentially pathogenic bacteria in the filtered and stored water. We therefore scrutinized a household sand filter with respect to As removal efficiency and the presence of fecal indicator bacteria in treated water as a function of filter operation before and after sand replacement. Quantification of As in the filtered water showed that periods of intense daily use followed by periods of non-use and even sand replacement did not significantly (pwater (95% removal). The first flush of water from the filter contained As concentrations below the drinking water limit and suggests that this water can be used without risk for human health. Colony forming units (CFUs) of coliform bacteria increased during filtration and storage from 5 ± 4 per 100mL in the groundwater to 5.1 ± 1.5 × 10(3) and 15 ± 1.4 × 10(3) per 100mL in the filtered water and in the water from the storage tank, respectively. After filter sand replacement, CFUs of Escherichia coli of samples contained CFUs of Enterococcus spp. No critical enrichment of fecal indicator bacteria belonging to E. coli or Enterococcus spp. was observed in the treated drinking water by qPCR targeting the 23S rRNA gene. The results demonstrate the efficient and reliable performance of household sand filters regarding As removal, but indicate a potential risk for human health arising from the enrichment of coliform bacteria during filtration and from E. coli cells that are introduced by sand replacement.

  5. Numerical Evaluation of Size Effect on the Stress-Strain Behaviour of Geotextile-Reinforced Sand

    DEFF Research Database (Denmark)

    Hosseinpour, I.; Mirmoradi, S.H.; Barari, Amin;

    2010-01-01

    This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers...... axial strain at failure in comparison with large-sized samples. The size effect on the behavior of samples became further apparent when the number of geotextile layers was increased or the confining pressure was decreased. In addition, the results indicated that the magnitude of the size effect...

  6. Effect of water content on the water repellency for hydrophobized sands

    Science.gov (United States)

    Subedi, S.; Kawamoto, K.; Kuroda, T.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Alternative earthen covers such as capillary barriers (CBs) and evapotranspirative covers are recognized as useful technical and low-cost solutions for limiting water infiltration and controlling seepage flow at solid waste landfills in semi-arid and arid regions. However, their application to the landfills at wet regions seems to be matter of concern due to loss of their impending capability under high precipitation. One of the possible techniques to enhance the impermeable properties of CBs is to alter soil grain surfaces to be water-repellent by mixing/coating hydrophobic agents (HAs). In order to examine a potential use of model sands hydrophobized with locally available and environmental-friendly HAs such as oleic acid (OA) and stearic acid (SA) for hydrophobic CBs. In the present study, we first characterized the effect of water content on the degree of water repellency (WR) for hydrophobized sands and volcanic ash soil at different depth. Secondly, the time dependency of the contact angle in hydrophobized sands and volcanic ash soils at different water content was evaluated. Further, the effects of hydrophobic organic matter contents on the WR of hydrophobized sands were investigated by horizontal infiltration test. We investigated the degree of WR as functions of volumetric water content (θ) of a volcanic ash soil samples from different depth and water adjusted hydrophobized sand samples with different ratio of HAs by using sessile drop method (SDM). The initial contact angle (αi) measured from SDM decreased gradually with increasing water content in OA and SA coated samples. Measured αi values for volcanic ash soils increased with increasing water content and reached a peak values of 111.7o at θ= 0.325 cm3 cm-3, where-after αi gradually decreased. Each test sample exhibited sharp decrease in contact angle with time at higher water content. Sorptivity values for oleic acid coated samples decreased with increasing HA content and reached the minimum

  7. Effect of thermal diffusion and electrostatic force on evolution of wind-blown sand flow

    Institute of Scientific and Technical Information of China (English)

    YUE Gao-wei; ZHENG Xiao-jing

    2007-01-01

    A theoretical model is suggested to mathematically describe the effect of thermal diffusion from a sand-bed on evolution of a wind-blown sand flow. An upward wind field is engendered by the thermal diffusion and the coupling interaction among the horizontal and upward wind flow, saltating grains, and a kind of electrostatic force exerted on the grains are considered in this theoretical model. The numerical results show that the effect of the thermal diffusion on the evolution process of wind-blown grain flow is quite obvious and very similar to the effect of the electrostatic force on the evolution. Not only the time for the entire system to reach a steady state (called the duration time), the transport rate of grains, the mass-flux profiles and the trajectory of saltating grains are affected by the thermal diffusion and the electrostatic force exerted on saltating grains,but also the wind profiles and the temperature profiles at the steady state are affected by the wind-blown sand flow.

  8. Calibration and validation of a sand model considering the effects of wave-induced principal stress axes rotation

    Institute of Scientific and Technical Information of China (English)

    LIU Peng; WANG Zhongtao; LI Xinzhong; CHAN Andrew

    2015-01-01

    Principal stress axes rotation influences the stress-strain behavior of sand under wave loading. A constitutive model for sand, which considers principal stress orientation and is based on generalized plasticity theory, is proposed. The new model, which employs stress invariants and a discrete memory factor during reloading, is original because it quantifies model parameters using experimental data. Four sets of hollow torsion experiments were conducted to calibrate the parameters and predict the capability of the proposed model, which describes the effects of principal stress orientation on the behavior of sand. The results prove the effectiveness of the proposed calibration method.

  9. An approach to managing cumulative effects to groundwater resources in the Alberta oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Fennell, J.; Forrest, Francine [WorleyParsons Canada, Infrastructure and Environment (Canada); Klebek, Margaret [Alberta Environment, Clean Energy Policy Branch (Canada)

    2011-07-01

    In the Athabasca region of Northern Alberta, oil sands activity has raised many concerns over how mining and extracting processes might affect groundwater quality and quantity. The groundwater management framework was developed by Alberta Environment to address these concerns by identifying and managing the potential environmental effects of oil sands activity on groundwater in a science-based manner. This paper develops the framework using risk identification and performance monitoring. The decision-making approach was conducted using decision support tools such as modeling, monitoring and management. Results showed the complexity and variability of groundwater conditions in the Athabasca region and pointed out that knowledge in this area is still developing. This paper presented how the groundwater management framework was developed and pointed out that it will have to be updated as new information arrives.

  10. Studying the Effects of Adding Silica Sand Nanoparticles on Epoxy Based Composites

    Directory of Open Access Journals (Sweden)

    Tahir Ahmad

    2013-01-01

    Full Text Available The research about the preparation of submicron inorganic particles, once conducted in the past decade, is now leading to prepare polymer matrix composite (PMC reinforced with nanofillers. The objective of present research is to study the modified effects of reinforcement dispersion of nanoparticle silica in epoxy resin on the physical properties, mechanical and thermal behaviour, and the microstructure of resultant composites. Stirrer mixing associated with manual mixing of silica sand nanoparticles (developed in our earlier research (Ahmad and Mamat, 2012 into epoxy was followed by curing being the adopted technique to develop the subject nanocomposites. Experimental values showed that 15 wt.% addition of silica sand nanoparticles improves Young’s modulus of the composites; however, a reduction in tensile strength was also observed. Number of holes and cavities produced due to improper mixing turn out to be the main cause of effected mechanical properties. Addition of silica sand nanoparticles causes a reduction in degree of crystallinity of the nanocomposites as being observed in differential scanning calorimetry (DSC analysis.

  11. Root growth, mycorrhization and physiological effects of plants growing on oil tailing sands

    Science.gov (United States)

    Boldt-Burisch, Katja M.; Naeth, Anne M.; Schneider, Bernd Uwe; Hüttl, Reinhard F.

    2015-04-01

    Surface mining creates large, intense disturbances of soils and produces large volumes of by-products and waste materials. After mining processes these materials often provide the basis for land reclamation and ecosystem restoration. In the present study, tailing sands (TS) and processed mature fine tailings (pMFT) from Fort McMurray (Alberta, Canada) were used. They represent challenging material for ecosystem rebuilding because of very low nutrient contents of TS and oil residuals, high density of MFT material. In this context, little is known about the interactions of pure TS, respectively mixtures of TS and MFT and root growth, mycorrhization and plant physiological effects. Four herbaceous plant species (Elymus trachycaulus, Koeleria macrantha, Deschampsia cespitosa, Lotus corniculatus) were chosen to investigate root development, chlorophyll fluorescence and mycorrhization intensity with and without application of Glomus mosseae (arbuscular mycorrhizae) on mainly tailing sands. Surprisingly both, plants growing on pure TS and plants growing on TS with additional AM-application showed mycorrhization of roots. In general, the mycorrhization intensity was lower for plants growing on pure tailings sands, but it is an interesting fact that there is a potential for mycorrhization available in tailing sands. The mycorrhizal intensity strongly increased with application of G. mosseae for K. macrantha and L. corniculatus and even more for E. trachycaulus. For D. cespitosa similar high mycorrhiza infection frequency was found for both variants, with and without AM-application. By the application of G. mosseae, root growth of E. trachycaulus and K. macrantha was significantly positively influenced. Analysis of leaf chlorophyll fluorescence showed no significant differences for E. trachycaulus but significant positive influence of mycorrhizal application on the physiological status of L. corniculatus. However, this effect could not be detected when TS was mixed with MFT

  12. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  13. Effects of slope gradient on hydro-erosional processes on an aeolian sand-covered loess slope under simulated rainfall

    Science.gov (United States)

    Zhang, F. B.; Yang, M. Y.; Li, B. B.; Li, Z. B.; Shi, W. Y.

    2017-10-01

    The aeolian sand-covered loess slope of the Wind-Water Erosion Crisscross Region of the Loess Plateau in China may play a key role in contributing excessive sediment to the Yellow River. Understanding its hydro-erosional processes is crucial to assessing, controlling and predicting soil and water losses in this region and maintaining the ecological sustainability of the Yellow River. Simulated rainfall (intensity 90 mm h-1) was used to investigate the runoff and soil loss from loess slopes with different slope gradients (18%, 27%, 36%, 47%, and 58%) and overlying sand layer thicknesses (0, 5 and 10 cm). As compared with uncovered loess slopes, an overlying sand layer delayed runoff production, reduced cumulative runoff and increased cumulative soil loss, as well as enhancing variations among slope gradients. Cumulative runoff and soil loss from the sand-covered loess slopes increased with increasing slope gradients and then slightly decreased, with a peak at about 47% gradient; they both were greater from the 10-cm sand-covered loess slope than from the 5-cm except for with 18% slope gradient. In general, differences in cumulative runoff between sand layer thicknesses became smaller, while those in cumulative soil loss became larger, with increasing slope gradient. Runoff and soil loss rates on the sand-covered loess slopes exhibited unimodal distributions during the rainstorms. Maximum values tended to occur at the same rain duration, and increased considerably with increasing slope gradient and sand layer thickness on slopes that were less than 47%. Liquefaction process might occur on the lower loess slopes covered with thinner sand layers but failures similar to shallow landslides might occur when the sand layer was thicker on steeper slopes. The presence of an overlying sand layer changed the relationship between runoff and soil loss rates during intense rainstorms and this change varied with different slope gradients. Our results demonstrated that the effects

  14. Growth of legume and nonlegume catch crops and residual-N effects in spring barley on coarse sand

    DEFF Research Database (Denmark)

    Askegaard, Margrethe; Eriksen, Jørgen

    2007-01-01

    Askegaard, M. and Eriksen, E. 2007. Growth of legume and nonlegume catch crops and residual-N effects in spring barley on coarse sand. J. Plant Nutrition and Soil Science, 170, 733-780.......Askegaard, M. and Eriksen, E. 2007. Growth of legume and nonlegume catch crops and residual-N effects in spring barley on coarse sand. J. Plant Nutrition and Soil Science, 170, 733-780....

  15. Effects of Moulding Sand Permeability and Pouring Temperatures on Properties of Cast 6061 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    Olawale Olarewaju Ajibola

    2015-01-01

    Full Text Available Effects of moulding sand permeabilities prepared from the combinations of four proportions of coarse and fine particle size mixtures and pouring temperatures varied from 700, 750, and 800 (±10°C were studied on the hardness, porosity, strength, and microstructure of cast aluminium pistons used in hydraulic brake master cylinder. Three sand moulds were prepared from each of the 80 : 20, 60 : 40, 40 : 60, and 20 : 80 ratios. The surfaces and microstructures of cast samples were examined using high resolution microscopic camera, metallurgical microscope with digital camera, and scanning electron microscope with EDX facilities. The best of the metallurgical properties were obtained from the combination of 80 : 20 coarse-fine sand ratio and 750 ± 10°C pouring temperature using as MgFeSi inoculant. An 8 : 25 ratio of coarse to fine grained eutectic aluminium alloy was obtained with enhanced metallographic properties. The cast alloy poured at 750 ± 1°C has a large number of fine grain formations assuming broom-resembling structures as shown in the 100 µm size SEM image.

  16. The Effectiveness of Silica Sand in Semi-Aerobic Stabilized Landfill Leachate Treatment

    Directory of Open Access Journals (Sweden)

    Ezlina Othman

    2010-12-01

    Full Text Available This study examines the suitability of natural silica sand as a low-cost adsorbent for the removal of ammoniacal nitrogen and heavy metals, particularly iron and zinc, from semi-aerobic stabilized landfill leachate. Leachate samples were collected from the Pulau Burung landfill site (PBLS in Penang, Malaysia. The above-mentioned contaminants are highlighted in this study because of their unsafe concentrations at PBLS. The effects of shaking time, settling time, and silica sand dosage on the study parameter removal efficiencies were investigated to predict the performance of the process. The adsorptions of ammoniacal nitrogen, iron, and zinc were judiciously described by Langmuir and Freundlich isotherm models. The optimum removal efficiencies of ammoniacal nitrogen, iron, and zinc obtained were 51%, 44.4%, and 39.2%, respectively, with a shaking time of 90 min, a settling time of 60 min, and with a dosage of 60 g (0.5 kg/L of silica sand. Based on the coefficient of determination (R2 values obtained from Langmuir and Freundlich isotherm models, ammoniacal nitrogen, iron, and zinc adsorption were better fitted to the Freundlich model.

  17. Effects of Different Ultrasound Irradiation Frequencies and Water Temperatures on Extraction Rate of Bitumen from Oil Sand

    Science.gov (United States)

    Okawa, Hirokazu; Saito, Tomonao; Hosokawa, Ryota; Nakamura, Takashi; Kawamura, Youhei; Sugawara, Katsuyasu

    2010-07-01

    Low (28 kHz) and high (200 kHz) frequency sonication combined with hot water treatments at 45 and 75 °C were investigated to assess the effects of different ultrasound frequencies and water temperatures on the extraction of bitumen from oil sand. A mechanical stirrer was also used to compare the efficiency of separation. Bitumen extraction tests were performed under argon, air, and nitrogen atmospheres. Sonication at 200 kHz was shown to extract bitumen effectively from oil sand at 75 °C. The bitumen extraction rate for sonication at 200 kHz was slightly higher than that at 28 kHz. For low temperature (45 °C) solutions, only sonication at 28 kHz could extract bitumen from oil sand, demonstrating that sonication at 28 kHz can effectively breakdown the oil sand aggregates into a suspension.

  18. Effects of Asian sand dust particles on the respiratory and immune system.

    OpenAIRE

    Honda, Akiko; Matsuda, Yugo; Murayama, Rumiko; Tsuji, Kenshi; Nishikawa, Masataka; Koike, Eiko; Yoshida, Seiichi; Ichinose, Takamichi; Takano, Hirohisa

    2013-01-01

    Epidemiologic studies have reported that Asian sand dust (ASD) particles can affect respiratory health; however, the mechanisms remain unclear. We investigated the effects of ASD on airway epithelial cells and immune cells, and their contributing factors to the effects. Human airway epithelial cells were exposed to ASD collected on 1-3 May (ASD1) and on 12-14 May (ASD2) 2011 in Japan and heat-treated ASD1 for excluding heat-sensitive substances (H-ASD) at a concentration of 0, 3, 30 or 90 µg ...

  19. Economic and environmental effects of the FQD on crude oil production from tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, B.; De Buck, A.; Afman, M. [CE Delft, Delft (Netherlands); Van den Berg, J.; Otten, G.J. [Carbon Matters, Den Haag (Netherlands)

    2013-05-15

    The production of unconventional crudes in Canada and Venezuela and exports of these crudes to the EU are investigated. In addition the potential economic and environmental impact of the proposed EU FQD measures (Fuel Quality Directive) on the production of crudes from tar sands and on new tar sand exploration projects are examined. CE Delft has analysed the impact by using a dedicated cost model. For existing projects, the model determines the effect on the basis of marginal production costs. For planned projects the model used the net present value (NPV) of proposed investments. The impacts were determined for a range of crude oil prices and FQD price effects. Combined, for existing and new projects together, the maximum effect would be at a price level at 60 USD/bbl, with savings of up to 19 Mt CO2/y at an FQD price differential of 3 euro/bbl. This overall effect would be substantial and come on top of the total emission reduction effect of the FQD of 60 Mt CO2/y, which will be achieved mostly by the blending of low-carbon fuels and reduced flaring and venting. As part of the reduction of transport greenhouse gas (GHG) emissions, the revised FQD obliges fuel suppliers to reduce these emissions by 6% by 2020 on a well-to-wheel basis. The EU is currently developing a methodology to differentiate fossil fuels on the basis of feedstock and GHG emissions. In the proposal, diesel produced from tar sands, has been given a default emission value of 108.5 gCO2 eq/MJ, while diesel from conventional crude was set at 89.1 gCO2 eq/MJ. The Commission's proposal is currently undergoing an impact assessment and is expected to be resubmitted to the Council later this year (2013)

  20. Relation Between Lack of Forgiveness and Depression: The Moderating Effect of Self-Compassion.

    Science.gov (United States)

    Chung, Myung-Sun

    2016-12-01

    Although an association between lack of forgiveness and poor mental health is known, prior studies have reported mixed findings of the relationship between lack of forgiveness and depressive symptoms. In an attempt to explain the strength differences between lack of forgiveness and depressive symptoms, this study examined the moderating effect of self-compassion. A total of 311 Korean teachers (89 men, 222 women; M age = 39.3 year, SD = 9.1) were asked to complete self-report questionnaires, including the Korean versions of the Trait Forgivingness Scale, the Self-Compassion Scale, and the Center for Epidemiologic Studies Depression Scale. Moderated multiple regression was used for analysis, and a buffering interaction of self-compassion was discovered. Specifically, self-compassion moderated the relationship between lack of forgiveness and depression; the relationship was stronger for those low on self-compassion.

  1. Effects of bedding with recycled sand on lying behaviors, udder hygiene, and preference of lactating Holstein dairy cows.

    Science.gov (United States)

    Kull, J A; Ingle, H D; Black, R A; Eberhart, N L; Krawczel, P D

    2017-09-01

    Effects of bedding with recycled sand and season on lying behaviors, hygiene, and preferences of late-lactation Holstein cows were studied. It was hypothesized that recycled sand will decrease lying time and increase hygiene scores due to increased moisture content and organic matter, and thus a preference for the control sand will be evident. Cows (n = 64) were divided into 4 groups (n = 8 per group) per season. In summer (August to September), cows were balanced by days in milk (268.1 ± 11.9 d) and parity (2.0 ± 0.2). In winter (January to February), mean DIM was 265.5 ± 34.1 d. Cows were assigned to 1 of 2 treatments using a crossover design with each treatment lasting 7 d (no-choice phase): bedding with recycled sand (RS; n = 32) or control (CO; clean sand; n = 32). Stocking density was maintained at 100%. The choice phase allowed cows to have access to either treatment with stocking density at 50%. Accelerometers recorded daily lying time, number of lying bouts per day, lying bout duration (min/bout), and total steps per day. Teat swabs, milk, sand samples, and udder hygiene scores were collected on d 0, 3, and 7 of each experimental week. Samples were cultured for streptococci, staphylococci, and gram-negative bacteria. Video data were used to assess bedding preferences. All data were analyzed using the MIXED and GLIMMIX procedures of SAS 9.4 (SAS Institute Inc., Cary, NC). Lying time was not affected by treatment, but cows did take more steps during winter. Bacterial counts were elevated for cows on recycled sand. A preference was observed for clean sand during the summer, but no preference was observed for sand during the winter. Regardless of bedding, the most commonly observed behavior was lying in the stalls, which suggested either bedding might be suitable. Caution should be used with this interpretation of preference, as sand was recycled only once. This limited reclamation was still sufficient to potentially alter the composition of sand, driving

  2. Effects of sand burial on growth and antioxidant enzyme activities of wheat (Triticum aestivum L.) in northern China

    Institute of Scientific and Technical Information of China (English)

    Hao Qu; HaLin Zhao; RuiLian Zhou; Jin Li; ChengChen Pan

    2015-01-01

    Growth and physiological responses of wheat to sand burial were studied in Horqin Sandy Land, to determine the impact on productivity and survival as well as antioxidant enzymes responses. This study consisted of one control (no sand) and four sand burial treatments:25%, 50%, 75%and 100%of seedling height, respectively. Minor burial (25%) had no effect on wheat growth and survival;deep burial (100%) was fatal, and the others had an intermediate effect. Thus, the survival limit to sand burial was equal to seedling height. Sand burial mainly decreased shoot biomass and crop yield, but had small effects on belowground biomass. Superoxide dismutase (SOD) activity increased with time after burial in all treatments with surviving plants. Peroxidase (POD) activity increased after six days under burial, and catalase (CAT) activity de-creased after burial, but recovered after 12 days. The concentration of malondialdehyde (MDA), a marker for oxidative stress, was low on the sixth day, but increased thereafter with burial depth. Thus, sand burial>25%should be avoided due to growth rate reduction leading to reduced crop yield, and even 25%burial showed physiological indicators of stress.

  3. Effect of sand and rubber surface on the lying behavior of lame dairy cows in hospital pens

    DEFF Research Database (Denmark)

    Bak, Anne Sandgrav; Herskin, Mette S.; Jensen, Margit Bak

    2016-01-01

    Housing lame cows in designated hospital pens with a soft surface may lessen the pain the animals feel when lying and changing position. This study investigated the effect of the lying surface on the behavior of lame cows in hospital pens. Thirty-two lame dairy cows were kept in individual hospital...... pens, provided with either 30-cm deep-bedded sand or 24-mm rubber mats during 24 h in a crossover design. On each surface, the lying behavior of each cow was recorded during 18 h. On deep-bedded sand, cows lay down more and changed position more often than when housed on the rubber surface. Furthermore......, a shorter duration of lying down and getting up movements and a shorter duration of lying intention movements were observed. These results suggest that lame dairy cows are more reluctant to change position on rubber compared with sand, and that sand is more comfortable to lie on. Thus, deep bedding...

  4. Effect of hardening method and structure of linking bridges on strength of water glass moulding sands

    OpenAIRE

    Stachowicz, M.; K. Granat

    2010-01-01

    The paper presents examination results of the effect of four hardening methods on structure of linking bridges in sandmixes containing hydrated sodium silicate. Test pieces prepared of the moulding sands containing 2.5 % of a binder with molar module between 2.4 and 2.6 were hardened with carbon dioxide, dried traditionally in an oven and hardened with microwaves at 2.54 GHz or using a combination of the CO2 process and microwave heating. It was revealed that the hardening method influences s...

  5. Some remarks on the effects of drugs, lack of sleep and loud noise on human performance.

    NARCIS (Netherlands)

    Sanders, A.F. & A.A. Bunt.

    1971-01-01

    Some literature is reviewed on the effect of some drugs, (amphetamine, hypnotics, alcohol), loud noise and sleep loss in test of time estimation, decision making, long term performance and short term memory. Results are most clear with respect to amphetamine, hypnotics and lack of sleep, in that amp

  6. Some remarks on the effects of drugs, lack of sleep and loud noise on human performance.

    NARCIS (Netherlands)

    Sanders, A.F. & A.A. Bunt.

    1971-01-01

    Some literature is reviewed on the effect of some drugs, (amphetamine, hypnotics, alcohol), loud noise and sleep loss in test of time estimation, decision making, long term performance and short term memory. Results are most clear with respect to amphetamine, hypnotics and lack of sleep, in that

  7. A study of the effects of LCD glass sand on the properties of concrete.

    Science.gov (United States)

    Wang, Her-Yung

    2009-01-01

    In order to study the recycling of discarded liquid crystal display (LCD) glass into concrete (LCDGC), a portion of the usual river sand was replaced by sand prepared from discarded LCD glass. Three different mix designs were regulated by the ACI method (fc(28)=21, 28, and 35MPa) with 0%, 20%, 40%, 60%, and 80% LCD glass sand replacements investigated; their engineering properties were determined. Test results revealed that, when compared to the design slump of 15cm, the 20% glass sand concrete for the three different mix designs kept good slump and slump flow. Furthermore, a slump loss ranging from 7 to 11cm was observed for specimens with 60% and 80% glass sand replacement for the design strengths of 28 and 35MPa. The compressive strengths of the concrete with glass sand replacement were higher than the design strengths. Moreover, the durability of the concrete with 20% glass sand replacement was better than that of the control group. Surface resistivity for specimens with different amounts of LCD glass sand replacement was also higher than that in the control group for mid to long curing ages. The sulfate attack in concrete with different amounts of glass sand replacement caused less weight loss than in the control group. Moderate chloride ion penetration was observed for glass sand concrete. Furthermore, the measured ultrasonic pulse velocities for LCD glass sand concrete specimens were higher than 4100m/s, which qualified these specimens as good concrete. OM and SEM indicate that the dense C-S-H gel hydrate was produced at the interface between the glass sand and cement paste. The test results indicate that the addition of 20% LCD glass sand to concrete satisfies the slump requirements and improves the strength and durability of concrete. This suggests that LCD glass sand can potentially be used as a recycled material in concrete applications.

  8. Vertical ground motion and its effects on liquefaction resistance of fully saturated sand deposits.

    Science.gov (United States)

    Tsaparli, Vasiliki; Kontoe, Stavroula; Taborda, David M G; Potts, David M

    2016-08-01

    Soil liquefaction has been extensively investigated over the years with the aim to understand its fundamental mechanism and successfully remediate it. Despite the multi-directional nature of earthquakes, the vertical seismic component is largely neglected, as it is traditionally considered to be of much lower amplitude than the components in the horizontal plane. The 2010-2011 Canterbury earthquake sequence in New Zealand is a prime example that vertical accelerations can be of significant magnitude, with peak amplitudes well exceeding their horizontal counterparts. As research on this topic is very limited, there is an emerging need for a more thorough investigation of the vertical motion and its effect on soil liquefaction. As such, throughout this study, uni- and bidirectional finite-element analyses are carried out focusing on the influence of the input vertical motion on sand liquefaction. The effects of the frequency content of the input motion, of the depth of the deposit and of the hydraulic regime, using variable permeability, are investigated and exhaustively discussed. The results indicate that the usual assumption of linear elastic response when compressional waves propagate in a fully saturated sand deposit does not always hold true. Most importantly post-liquefaction settlements appear to be increased when the vertical component is included in the analysis.

  9. Effect of environmental conditions on the spectroscopic signature of DNT in sand

    Science.gov (United States)

    Blanco, Alejandro; Mina, Nairmen; Castro, Miguel E.; Castillo-Chara, Jairo; Hernandez-Rivera, Samuel P.

    2005-06-01

    Landmines have been a part of war technology for many years. As a result of the continued and indiscriminate use in approximately 90 countries landmines pose a severe and ever growing problem and a daily risk. Raman Spectroscopy is capable of providing rich information about the molecular structure of the sample and pinpoint detection of many chemicals, both of organic and inorganic nature. The presence of landmines in soils can be detected by Raman Spectroscopy sensing in a Point Detection modality, using characteristic vibrational signals of each explosive present in landmines. Detection of 2,4-DNT in sand and studies on how the vibrational signatures of 2,4-DNT is modified by interacting with soil particles and environmental conditions is reported. Raman Microspectrometers equipped with 514 nm and 785 nm laser excitation lines were used. The work focused in how the spectroscopic signatures of DNT in contact with Ottawa Sand are affected by the presence of humidity, pH, temperature, UV light and reaction times. Samples of mixtures of sand/2,4-DNT were analyzed by Raman Spectroscopy at 10, 50 and 100% water content and temperatures in range of 40-80 °C. Mixtures were also analyzed at different pH: 4, 7 and 10 and under ultraviolet light at 254 nm. Raman spectra were taken as a function of time in an interval from 24 to 336 hours (two weeks). Characteristic signals of 2,4-DNT were analyzed in different ranges 100-3800 cm-1, 600-1200 cm-1, 300-1700 cm-1 and 2800-3500 cm-1. The effect of these variables was measured during 45 consecutive days. It was confirmed that the decrease of characteristic vibrational signatures of 2,4-DNT can be attributed to increase of the degradation of 2,4-DNT by the simulated environmental conditions. Spectroscopic characterization of degradation products, both in contact with sand as well as airborne is under way. These results will make possible the development of highly sensitive sensors for detection of explosives materials and

  10. The effect of wind and precipitation on vegetation and biogenic crust covers in the Sde-Hallamish sand dunes

    Science.gov (United States)

    Amir, Raz; Kinast, Shai; Tsoar, Haim; Yizhaq, Hezi; Zaady, Eli; Ashkenazy, Yosef

    2014-03-01

    Vegetation and biogenic crust covers play an important role in sand dune stabilization, yet there is a lack of high temporal and spatial resolution data on sand dune cover. A field experiment, aimed at measuring the dynamics of biogenic crust and vegetation in sand dunes, was conducted at the Sde-Hallamish sand dunes in the northwestern Negev Desert, Israel, from July 2008 to August 2010. The climate of the Sde-Hallamish sand dunes is arid (the mean annual precipitation over the past 13 years is 61 mm), and the dunes are linear and partially stable, mainly due to the presence of biogenic crust and partially due to the presence of vegetation. In July 2008, 10×10 m plots on the four dune habitats (crest, interdune, north slope, and south slope) were treated as follows: (i) removal of vegetation and biogenic crust, (ii) removal of biogenic crust only, (iii) removal of vegetation only, (iv) partial removal of biogenic crust and vegetation, and (v) control plot. The surface coverage of sand, biogenic crust, and vegetation was monitored on a monthly basis, using a remote-sensing technique especially developed for the Sde-Hallamish sand dunes. It was found that strong wind events, with durations of several days, accounted for the coverage changes in biogenic crust and vegetation. The response to precipitation was much slower. In addition, no rehabilitation of biogenic crust and vegetation was observed within the experiment time period. The changes in biogenic crust cover were not necessarily related to changes in dune dynamics, since often an increase in biogenic crust cover is a result of wind erosion that exposes old crust that was buried under the sand; wind hardly erodes biogenic crust at all due to its high durability to wind action. The Sde-Hallamish dunes seem to have become more active as a result of a prolonged drought during the past several years. The field experiment reported here indicates that biogenic crust cover exhibits large seasonal variations that are

  11. Present status of effect of microorganisms from sand beach on public health

    Directory of Open Access Journals (Sweden)

    Emmanuel Velonakis

    2014-09-01

    Full Text Available Microorganisms are significant components of beach sand. According to the research, all kind of microorganisms have been isolated from beach sand; certain genera and species are potential pathogens for humans and animals. In resort areas, especially during the summer, certain infections (e.g. gastroenteritis and dermatitis are usually related to polluted bathing water. Lately, the interest of scientists is also focused on the potential association of some of the above diseases with the beach sand. Relatively, recent epidemiological studies in the USA revealed positive correlation between time spent at the beach and gastroenteritis. New parameters such as wind blowing and beach users’ density are also introduced for discussion in association with the sand microbial load. Regarding the preventative measures, the microbiological quality of beach sand can be improved by raising the general level of hygiene, as well as by using simple methods, such as sweeping and aeration of the sand, together with constant beach supervision.

  12. Present status of effect of microorganisms from sand beach on public health

    Institute of Scientific and Technical Information of China (English)

    Emmanuel Velonakis; Dimitra Dimitriadi; Emmanuel Papadogiannakis; Alkiviades Vatopoulos

    2014-01-01

    Microorganisms are significant components of beach sand. According to the research, all kind of microorganisms have been isolated from beach sand; certain genera and species are potential pathogens for humans and animals. In resort areas, especially during the summer, certain infections (e.g. gastroenteritis and dermatitis) are usually related to polluted bathing water. Lately, the interest of scientists is also focused on the potential association of some of the above diseases with the beach sand. Relatively, recent epidemiological studies in the USA revealed positive correlation between time spent at the beach and gastroenteritis. New parameters such as wind blowing and beach users’ density are also introduced for discussion in association with the sand microbial load. Regarding the preventative measures, the microbiological quality of beach sand can be improved by raising the general level of hygiene, as well as by using simple methods, such as sweeping and aeration of the sand, together with constant beach supervision.

  13. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2010-07-01

    Full Text Available Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4 min is very close to that measured after traditional drying at 110 °C for 120 min. So, application of microwave hardening ensures significant shortening of the process time to the value comparable with CO2 hardening but guaranteeing over 10-fold increase of mechanical properties. Analysis of SEM images of hardened moulding sands permitted explaining differences in quality parameters of moulding sands by connecting them with structure of the created bonding bridges.

  14. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    OpenAIRE

    Stachowicz, M.; K. Granat; Nowak, D.

    2010-01-01

    Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4...

  15. Effects of artificial sand fixing on community characteristics of a rare desert shrub.

    Science.gov (United States)

    Liu, Huiliang; Tao, Ye; Qiu, Dong; Zhang, Daoyuan; Zhang, Yongkuan

    2013-10-01

    Eremosparton songoricum (Fabaceae) is a rare, native, clonal small shrub of the deserts of central Asia. Although human activities have greatly fragmented the distribution of E. songoricum, it occurs in areas where artificial sand fixing (AS) has been implemented. We sought to explore whether AS promotes survival and growth of E. songoricum. In the Gurbantunggut Desert of northwestern China in June 2010, we established 10 plots in an area where sand fixing occurred (5-10 years previously) and 11 plots on original sand substrate on which some plants had settled without fixing sand. Sand fixing changed soil properties and biological characteristics in sand-fixed plots. The soil surface where sand fixing occurred was covered by algal crusts and some lichen, but not bare sand (BS). Soil nutrients; water content of deep soil (30-150 cm); overall plant and herbaceous species richness, diversity, abundance, and cover; above- and belowground biomass; and cover, biomass, and height of E. songoricum in the sand-fixed plots were significantly greater than in plots of BS. However, distribution of E. songoricum individuals in the 2 types of plots did not differ. Our results indicate AS may enhance survival of E. songoricum and increase the overall diversity and stability of the desert plant community. We suggest AS as a way to protect this rare desert plant in situ. © 2013 Society for Conservation Biology.

  16. Effects of the Magnus and Saffman forces on the saltation trajectories of sand grain

    Science.gov (United States)

    Zou, Xue-Yong; Cheng, Hong; Zhang, Chun-Lai; Zhao, Yan-Zhi

    2007-10-01

    Saltating sand grains are the primary component of airborne sand and account for 75% of all sand transport flux. The saltation height and horizontal distance traveled by sand grains are key factors in sand-control engineering. In addition to gravity and aerodynamic drag, the Magnus and Saffman forces also play important roles in saltation. To quantify the magnitudes of these forces in saltation we used high-speed multi-flash photography to observe the movement of saltating sand grains in a wind tunnel; this proved to be an efficient technique for determining the movement and rotational velocities of grains of natural sand with grain sizes ranging from 0.2 to 0.3 mm and shear velocities ( u*) of 0.67, 0.83, and 0.87 m s - 1 . The rotational speed of saltating sand grains varied between 200 and 800 rev s - 1 ; mean clockwise and anticlockwise rotational speeds were nearly identical, and both increased with increasing saltation height. With saltation heights divided into 1 cm intervals, the rotational speeds followed a Lorentzian distribution. Calculations based on a saltation model showed that the maximum increases in saltation height and in horizontal distance due to the Magnus force were 10.2 and 24.9%, respectively. The rate of increase of both parameters increased with increasing lift-off angle. The maximum increases in saltation height and horizontal distance of sand grains caused by the Saffman force were only 4.6% and 3.7%, respectively.

  17. Effect of Additives on Green Sand Molding Properties using Design of Experiments and Taguchi's Quality Loss Function - An Experimental Study

    Science.gov (United States)

    Desai, Bhagyashree; Mokashi, Pavani; Anand, R. L.; Burli, S. B.; Khandal, S. V.

    2016-09-01

    The experimental study aims to underseek the effect of various additives on the green sand molding properties as a particular combination of additives could yield desired sand properties. The input parameters (factors) selected were water and powder (Fly ash, Coconut shell and Tamarind) in three levels. Experiments were planned using design of experiments (DOE). On the basis of plans, experiments were conducted to understand the behavior of sand mould properties such as compression strength, shear strength, permeability number with various additives. From the experimental results it could be concluded that the factors have significant effect on the sand properties as P-value found to be less than 0.05 for all the cases studied. The optimization based on quality loss function was also performed. The study revealed that the quality loss associated with the tamarind powder was lesser compared to other additives selected for the study. The optimization based on quality loss function and the parametric analysis using ANOVA suggested that the tamarind powder of 8 gm per Kg of molding sand and moisture content of 7% yield better properties to obtain sound castings.

  18. Saltation of Non-Spherical Sand Particles

    Science.gov (United States)

    Wang, Zhengshi; Ren, Shan; Huang, Ning

    2014-01-01

    Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement. PMID:25170614

  19. Effect of consolidation ratios on maximum dynamic shear modulus of sands

    Institute of Scientific and Technical Information of China (English)

    Yuan Xiaoming; Sun Jing; Sun Rui

    2005-01-01

    The dynamic shear modulus (DSM) is the most basic soil parameter in earthquake or other dynamic loading conditions and can be obtained through testing in the field or in the laboratory. The effect of consolidation ratios on the maximum DSM for two types of sand is investigated by using resonant column tests. And, an increment formula to obtain the maximum DSM for cases of consolidation ratio kc>1 is presented. The results indicate that the maximum DSM rises rapidly when kc is near 1 and then slows down, which means that the power function of the consolidation ratio increment kc-1 can be used to describe the variation of the maximum DSM due to kc>1. The results also indicate that the increase in the maximum DSM due to kc>1 is significantly larger than that predicted by Hardin and Black's formula.

  20. Efficient microplastics extraction from sand. A cost effective methodology based on sodium iodide recycling.

    Science.gov (United States)

    Kedzierski, Mikaël; Le Tilly, Véronique; César, Guy; Sire, Olivier; Bruzaud, Stéphane

    2017-02-15

    Evaluating the microplastics pollution on the shores requires overcoming the technological and economical challenge of efficient plastic extraction from sand. The recovery of dense microplastics requires the use of NaI solutions, a costly process. The aim of this study is to decrease this cost by recycling the NaI solutions and to determine the impact of NaI storage. For studying the NaI recyclability, the solution density and the salt mass have been monitored during ten life cycles. Density, pH and salt mass have been measured for 40days to assess the storage effect. The results show that NaI solutions are recyclable without any density alterations with a total loss of 35.9% after the 10cycles of use. During storage, chemical reactions may appear but are reversible. Consequently, the use of recycling methods allows for a significant cost reduction. How far the plastic extraction by dense solutions is representative is discussed.

  1. Effect of sand versus grass training surfaces during an 8-week pre-season conditioning programme in team sport athletes.

    Science.gov (United States)

    Binnie, Martyn John; Dawson, Brian; Arnot, Mark Alexander; Pinnington, Hugh; Landers, Grant; Peeling, Peter

    2014-01-01

    This study compared the use of sand and grass training surfaces throughout an 8-week conditioning programme in well-trained female team sport athletes (n = 24). Performance testing was conducted pre- and post-training and included measures of leg strength and balance, vertical jump, agility, 20 m speed, repeat speed (8 × 20 m every 20 s), as well as running economy and maximal oxygen consumption (VO2max). Heart rate (HR), training load (rating of perceived exertion (RPE) × duration), movement patterns and perceptual measures were monitored throughout each training session. Participants completed 2 × 1 h conditioning sessions per week on sand (SAND) or grass (GRASS) surfaces, incorporating interval training, sprint and agility drills, and small-sided games. Results showed a significantly higher (P training load in the SAND versus GRASS group throughout each week of training, plus some moderate effect sizes to suggest lower perceptual ratings of soreness and fatigue on SAND. Significantly greater (P training surfaces throughout an 8-week conditioning programme can significantly increase the relative exercise intensity and training load, subsequently leading to superior improvements in aerobic fitness.

  2. The Effects of Lack of Joint Goal Planning on Divorce over 10 Years.

    Science.gov (United States)

    Gere, Judith; Almeida, David M; Martire, Lynn M

    Given the negative consequences of divorce on health and well-being, it is important to try to identify its predictors. In the current study we used data from the National Survey of Midlife Development (N = 2801) to examine the longitudinal effects of lack of joint goal planning with a romantic relationship partner on divorce over a 10-year period. Multilevel regression analyses showed that lack of joint planning with the relationship partner was associated with a 19% increase in the odds of divorce, even when controlling for various demographic (i.e., age, gender, relationship length, number of children in the household), individual (i.e., neuroticism, positive affect, negative affect, physical symptoms, planning), and relationship (i.e., marital empathy, partner strain, partner disagreement, marital satisfaction, commitment). These results demonstrate the importance of considering one's partner when making decisions and plans for the future, given that it has clear implications for relationship dissolution.

  3. Immunotoxic effects of oil sands-derived naphthenic acids to rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, Gillian Z.; Hogan, Natacha S. [Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI (Canada); Koellner, Bernd [Friedrich Loeffler Institute, Federal Research Institute of Animal Health, Institute of Immunology, Greifswald (Germany); Thorpe, Karen L.; Phalen, Laura J. [Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI (Canada); Wagner, Brian D. [Department of Chemistry, University of Prince Edward Island, Charlottetown (Canada); Heuvel, Michael R. van den, E-mail: mheuvel@upei.ca [Canadian Rivers Institute, Department of Biology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI (Canada)

    2013-01-15

    Naphthenic acids are the major organic constituents in waters impacted by oil sands. To investigate their immunotoxicity, rainbow trout (Oncorhynchus mykiss) were injected with naphthenic acids extracted from aged oil sands tailings water. In two experiments, rainbow trout were injected intraperitoneally with 0, 10, or 100 mg/kg of naphthenic acids, and sampled after 5 or 21 d. Half of the fish from the 21 d exposure were co-exposed to inactivated Aeromonas salmonicida (A.s.) to induce an immune response. A positive control experiment was conducted using an intraperitoneal injection of 100 mg/kg of benzo[a]pyrene, a known immune suppressing compound. T-lymphocytes, B-lymphocytes, thrombocytes, and myeloid cells were counted in blood and lymphatic tissue using flow cytometry. In the 5 d exposure, there was a reduction in blood leucocytes and spleen thrombocytes at the 100 mg/kg dose. However, at 21 d, leucocyte populations showed no effects of exposure with the exception that spleen thrombocyte populations increase at the 100 mg/kg dose. In the 21 d exposure, B- and T-lymphocytes in blood showed a significant Dose Multiplication-Sign A.s. interaction, indicating stimulated blood cell proliferation due to naphthenic acids alone as well as due to A.s. Naphthenic acid injections did not result in elevated bile fluorescent metabolites or elevated hepatic EROD activity. In contrast to naphthenic acids exposures, as similar dose of benzo[a]pyrene caused a significant decrease in B- and T-lymphocyte absolute counts in blood and relative B-lymphocyte counts in spleen. Results suggest that the naphthenic acids may act via a generally toxic mechanism rather than by specific toxic effects on immune cells.

  4. Effect of Different Forcing Processes on the Longshore Sediment Transport at the Sand Motor, The Netherlands

    NARCIS (Netherlands)

    Kaji, A.O.; Luijendijk, A.P.; van Thiel de Vries, J.S.M.; De Schipper, M.A.; Stive, M.J.F.

    2014-01-01

    The Sand Motor is a pilot project of a ‘mega-nourishment’ built in the Dutch coast in 2011. In order to understand which conditions reshape those mega-nourishments the influence of different types of forcing on the longshore sediment transport along the Sand Motor has been assessed in this paper usi

  5. Inflammatory and genotoxic effects of sanding dust generated from nanoparticle-containing paints and lacquers

    DEFF Research Database (Denmark)

    Saber, Anne Thoustrup; Koponen, Ismo Kalevi; Jensen, Keld Alstrup

    2012-01-01

    Nanoparticles are increasingly used in paints and lacquers. Little is known of the toxicity of nanoparticles incorporated in complex matrices and released during different phases of the life cycle. DNA damaging activity and inflammogenicity of sanding dust sampled during standardised sanding of b...

  6. Measuring and modeling the effect of surface moisture on the spectral reflectance of coastal beach sand

    NARCIS (Netherlands)

    Nolet, Corjan; Poortinga, Ate; Roosjen, Peter; Bartholomeus, Harm; Ruessink, Gerben

    2014-01-01

    Surface moisture is an important supply limiting factor for aeolian sand transport, which is the primary driver of coastal dune development. As such, it is critical to account for the control of surface moisture on available sand for dune building. Optical remote sensing has the potential to measure

  7. Effect of Different Forcing Processes on the Longshore Sediment Transport at the Sand Motor, The Netherlands

    NARCIS (Netherlands)

    Kaji, A.O.; Luijendijk, A.P.; van Thiel de Vries, J.S.M.; De Schipper, M.A.; Stive, M.J.F.

    2014-01-01

    The Sand Motor is a pilot project of a ‘mega-nourishment’ built in the Dutch coast in 2011. In order to understand which conditions reshape those mega-nourishments the influence of different types of forcing on the longshore sediment transport along the Sand Motor has been assessed in this paper

  8. Effect of Initial Principal Stress Direction on the Dynamic Characteristics of Carbonate Sand

    Institute of Scientific and Technical Information of China (English)

    Yu Haizhen; Zhao Wenguang; Wang Ren; Li Jianguo; He Yang

    2005-01-01

    The dynamic characteristics of carbonate sand under wave loads are very important for constructions on the ocean floor. The initial principal stress direction has been known to exert some influence on the dynamic characteristics of sand during cyclic loading. In an effort to investigate this aspect of the problem, several series of cyclic undrained tests were carried out on a saturated and loose sample of carbonate sand using a geotechnical static and dynamic universal triaxial shear apparatus. In this test apparatus, a hollow cylindrical sand specimen is subjected to a simultaneous application of both triaxial and torsional modes of shear stresses, which brings about the continuous rotation of principal stress axes. The test results indicated that the initial principal stress direction has a considerable influence on the dynamic strength of loose carbonate sand and with the increase of initial orientation of principal stress, dynamic strength will be reduced, the cyclic pore pressure increased, but the residual pore pressure reduced.

  9. Experimental study of seismic cyclic loading effects on small strain shear modulus of saturated sands

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yan-guo; CHEN Yun-min; HUANG Bo

    2005-01-01

    The seismic loading on saturated soil deposits induces a decrease in effective stress and a rearrangement of the soil-particle structure, which may both lead to a degradation in undrained stiffness and strength of soils. Only the effective stress influence on small strain shear modulus Gmax is considered in seismic response analysis nowadays, and the cyclic shearing induced fabric changes of the soil-particle structure are neglected. In this paper, undrained cyclic triaxial tests were conducted on saturated sands with the shear wave velocity measured by bender element, to study the influences of seismic loading on Gmax. And Gmax of samples without cyclic loading effects was also investigated for comparison. The test results indicated that Gmax under cyclic loading effects is lower than that without such effects at the same effective stress, and also well correlated with the effective stress variation. Hence it is necessary to reinvestigate the determination of Gmax in seismic response analysis carefully to predict the ground responses during earthquake more reasonably.

  10. Effect of liming on yield and quality of peppermint and Sachalin mint in fine sand soil of Northern Finland

    OpenAIRE

    Aflatuni, Abbas; Uusitalo, Jouko; Ek, Sari; Hohtola, Anja

    2003-01-01

    Soil acidity commonly limits plant production in the fine sand soil of Northern Finland, which often has a low pH (5.5-6.5) and contains low levels of Ca and Mg. The effect of five liming (10% Mg and 19% Ca) levels, 0, 4, 8, 12, and 16 tons ha -1 , on the herb and essential oil yield and menthol and menthone content of two mint species (peppermint, Mentha x piperita, a variety of Black Mitcham and Sachalin mint, Mentha arvensis var. sacchalinensis) cultivated in fine sand soil in Northern Fin...

  11. Closing the performance gap : the challenge for cumulative effects management in Alberta's Athabasca oil sands region

    Energy Technology Data Exchange (ETDEWEB)

    Kennett, S.A. [Calgary Univ., AB (Canada). Canadian Inst. of Resources Law

    2007-05-15

    This paper examined cumulative effects management strategies adopted by the Cumulative Environmental Management Association (CEMA) and the Regional Sustainable Development Strategy (RSDS), multi-stakeholder collaborations established after a set of public hearings conducted before Alberta's Energy and Utilities Board (EUB) in 1997. The initiatives were designed to examine challenges related to the management of cumulative effects of large-scale oil sands developments. However, the scale, pace, and intensity of oil sands development has now exceeded initial expectations, and concerns have been expressed over the inability of the initiatives to adequately address cumulative effects management issues. Stakeholders involved in the initiatives have also expressed doubts over the ability of the initiatives to achieve tangible results. This paper provided details of 16 interviews conducted with participants in CEMA as well as a variety of industry members, and government agencies. Respondents indicated that CEMA's performance gap was caused by the complexity of issues related to cumulative effects management, deficiencies in the initiative's organizational processes, and divergence between participants on objectives. Approaches to narrowing CEMA's performance gap must consider the rapid pace of oil sands development and the significant obstacles to cumulative effects management within legal, institutional, and policy structures. It was concluded that intense conflict around oil sands development is likely if CEMA's performance gaps are not addressed. refs.

  12. The Effect of Water Cut on Sand Production%水侵对油井出砂的影响

    Institute of Scientific and Technical Information of China (English)

    张建国

    2001-01-01

    提出了地层出砂过程包括剪切破坏产生屈服区和砂粒运移两个阶段的概念,分析了水侵对油井出砂的影响,水侵加速地层出砂的原因如下:产水能溶解砂粒之间的一部分胶结物,使地层的胶结强度下降;粘土膨胀,渗透率降低;破坏油流的连续性;产生水锁效应,增加油流阻力。同时,建立了粘着力模型,利用该模型分析了水侵量对油井出砂的影响。%It is pointed out in this paper that the sand production includes two steps. The first step is the development of the plastic area induced by the shear failure of the formation. And the second step is that the sand grains are carried by the fluid flow. The effect of the water cut on the sand production is also analyzed. Sand production is increased by the water cut owing to the following reasons: 1. The bonding material among the sand grains is dissolved by the water, which cause the formation strength decrease. 2. The permeability is decreased by clay dilation. 3. The water destroys the oil continuity. 4. The water lock is formed, which increases the fluid flow resistance. Meanwhile, the model to predict the cohesion force is developed. Using this model, the effect of the water cut quantity on the sand production is analyzed.

  13. Effect of Polyphosphate-accumulating Organisms on Phosphorus Mobility in Variably Saturated Sand Columns

    Science.gov (United States)

    Stockton, M.; Rojas, C.; Regan, J. M.; Saia, S. M.; Buda, A. R.; Carrick, H. J.; Walter, M. T.

    2016-12-01

    Excessive application of phosphorus-containing fertilizer along with incomplete knowledge about the factors affecting phosphorus transport and mobility has allowed for a growing number of cases of eutrophication in water bodies. Previous research on enhanced biological phosphorus removal (EBPR) systems used in wastewater treatment plants (WWTPs) has identified polyphosphate-accumulating organisms (PAOs) that are known to accumulate and release phosphorus depending on aerobic/anaerobic conditions. Under anaerobic conditions, intracellular polyphosphate (poly-P) bodies are hydrolyzed releasing phosphate, while under aerobic conditions phosphate is taken up and poly-P inclusions are reformed. The presence of PAOs outside of WWTPs has been shown, but their potential impact on phosphorus mobility in other contexts is not as well known. To study that potential impact, sand columns were subjected to alternating cycles of saturation and unsaturation to mimic variably saturated soils and the resultant anaerobic and aerobic conditions that select for PAOs in a WWTP. Pore water samples collected from sterile control columns and columns inoculated with PAOs from a WWTP were compared during each cycle to monitor changes in dissolved inorganic phosphate and total phosphorus concentrations. In addition, continuous redox data were collected to confirm reducing conditions developed during periods of saturation. Sand particles will be subjected to FISH and DAPI staining to visualize PAOs using probes developed for PAOs in EBPR processes and to determine if changes in intracellular poly-P are detectable between the two cycles in the inoculated columns. Studying the effects of PAOs on phosphorus mobility in these controlled column experiments can contribute to understanding phosphorus retention and release by naturally occurring PAOs in terrestrial system, which ultimately can improve the development of management practices that mitigate phosphorus pollution of water bodies.

  14. Nicotine anxiogenic and rewarding effects are decreased in mice lacking β-endorphin

    Science.gov (United States)

    Trigo, José M.; Zimmer, Andreas; Maldonado, Rafael

    2009-01-01

    The endogenous opioid system plays an important role in the behavioral effects of nicotine. Thus, μ-opioid receptor and the endogenous opioids derived from proenkephalin are involved in the central effects of nicotine. However, the role played by the different endogenous opioid peptides in the acute and chronic effects of nicotine remains to be fully established. Mice lacking β-endorphin were acutely injected with nicotine at different doses to evaluate locomotor, anxiogenic and antinociceptive responses. The rewarding properties of nicotine were evaluated by using the conditioned place-preference paradigm. Mice chronically treated with nicotine were acutely injected with mecamylamine to study the behavioral expression of nicotine withdrawal. Mice lacking β-endorphin exhibited a spontaneous hypoalgesia and hyperlocomotion and a reduction on the anxiogenic and rewarding effects induced by nicotine. Nicotine induced similar antinociception and hypolocomotion in both genotypes and no differences were found in the development of physical dependence. The dissociation between nicotine rewarding properties and physical dependence suggests a differential implication of β-endorphin in these addictive related responses. PMID:19376143

  15. Spirulina platensis Lacks Antitumor Effect against Solid Ehrlich Carcinoma in Female Mice

    Science.gov (United States)

    Barakat, Waleed; Elshazly, Shimaa M.; Mahmoud, Amr A. A.

    2015-01-01

    Spirulina is a blue-green alga used as a dietary supplement. It has been shown to possess anti-inflammatory, antioxidant, and hepatoprotective properties. This study was designed to evaluate the antitumor effect of spirulina (200 and 800 mg/kg) against a murine model of solid Ehrlich carcinoma compared to a standard chemotherapeutic drug, 5-fluorouracil (20 mg/kg). Untreated mice developed a palpable solid tumor after 13 days. Unlike fluorouracil, spirulina at the investigated two dose levels failed to exert any protective effect. In addition, spirulina did not potentiate the antitumor effect of fluorouracil when they were administered concurrently. Interestingly, their combined administration resulted in a dose-dependent increase in mortality. The present study demonstrates that spirulina lacks antitumor effect against this model of solid Ehrlich carcinoma and increased mortality when combined with fluorouracil. However, the implicated mechanism is still elusive. PMID:26366170

  16. Spirulina platensis Lacks Antitumor Effect against Solid Ehrlich Carcinoma in Female Mice

    Directory of Open Access Journals (Sweden)

    Waleed Barakat

    2015-01-01

    Full Text Available Spirulina is a blue-green alga used as a dietary supplement. It has been shown to possess anti-inflammatory, antioxidant, and hepatoprotective properties. This study was designed to evaluate the antitumor effect of spirulina (200 and 800 mg/kg against a murine model of solid Ehrlich carcinoma compared to a standard chemotherapeutic drug, 5-fluorouracil (20 mg/kg. Untreated mice developed a palpable solid tumor after 13 days. Unlike fluorouracil, spirulina at the investigated two dose levels failed to exert any protective effect. In addition, spirulina did not potentiate the antitumor effect of fluorouracil when they were administered concurrently. Interestingly, their combined administration resulted in a dose-dependent increase in mortality. The present study demonstrates that spirulina lacks antitumor effect against this model of solid Ehrlich carcinoma and increased mortality when combined with fluorouracil. However, the implicated mechanism is still elusive.

  17. Spirulina platensis Lacks Antitumor Effect against Solid Ehrlich Carcinoma in Female Mice.

    Science.gov (United States)

    Barakat, Waleed; Elshazly, Shimaa M; Mahmoud, Amr A A

    2015-01-01

    Spirulina is a blue-green alga used as a dietary supplement. It has been shown to possess anti-inflammatory, antioxidant, and hepatoprotective properties. This study was designed to evaluate the antitumor effect of spirulina (200 and 800 mg/kg) against a murine model of solid Ehrlich carcinoma compared to a standard chemotherapeutic drug, 5-fluorouracil (20 mg/kg). Untreated mice developed a palpable solid tumor after 13 days. Unlike fluorouracil, spirulina at the investigated two dose levels failed to exert any protective effect. In addition, spirulina did not potentiate the antitumor effect of fluorouracil when they were administered concurrently. Interestingly, their combined administration resulted in a dose-dependent increase in mortality. The present study demonstrates that spirulina lacks antitumor effect against this model of solid Ehrlich carcinoma and increased mortality when combined with fluorouracil. However, the implicated mechanism is still elusive.

  18. Predicting Effects of Ocean Acidification and Warming on Algae Lacking Carbon Concentrating Mechanisms.

    Directory of Open Access Journals (Sweden)

    Janet E Kübler

    Full Text Available Seaweeds that lack carbon-concentrating mechanisms are potentially inorganic carbon-limited under current air equilibrium conditions. To estimate effects of increased atmospheric carbon dioxide concentration and ocean acidification on photosynthetic rates, we modeled rates of photosynthesis in response to pCO2, temperature, and their interaction under limiting and saturating photon flux densities. We synthesized the available data for photosynthetic responses of red seaweeds lacking carbon-concentrating mechanisms to light and temperature. The model was parameterized with published data and known carbonate system dynamics. The model predicts that direction and magnitude of response to pCO2 and temperature, depend on photon flux density. At sub-saturating light intensities, photosynthetic rates are predicted to be low and respond positively to increasing pCO2, and negatively to increasing temperature. Consequently, pCO2 and temperature are predicted to interact antagonistically to influence photosynthetic rates at low PFD. The model predicts that pCO2 will have a much larger effect than temperature at sub-saturating light intensities. However, photosynthetic rates under low light will not increase proportionately as pCO2 in seawater continues to rise. In the range of light saturation (Ik, both CO2 and temperature have positive effects on photosynthetic rate and correspondingly strong predicted synergistic effects. At saturating light intensities, the response of photosynthetic rates to increasing pCO2 approaches linearity, but the model also predicts increased importance of thermal over pCO2 effects, with effects acting additively. Increasing boundary layer thickness decreased the effect of added pCO2 and, for very thick boundary layers, overwhelmed the effect of temperature on photosynthetic rates. The maximum photosynthetic rates of strictly CO2-using algae are low, so even large percentage increases in rates with climate change will not

  19. EFFECTS OF SALT MARSH ALTOSID EXPOSURE ON FEMALE GROWTH & PRODUCTION IN GULF SAND FIDDLER CRAB, UCA PANACEA

    Science.gov (United States)

    Effects of Salt Marsh Altosid(R) Exposure on Female Growth and Reproduction in the Gulf Sand Fiddler Crab, Uca panacea (Abstract). Presented at the 62nd Annual Meeting of the Association of Southern Biologists, 4-7 July 2001, New Orleans, LA. 1 p.Adult Uca panacea were p...

  20. Aeolian sand transport and aeolian deposits on Venus: A review

    Science.gov (United States)

    Kreslavsly, Mikhail A.; Bondarenko, Nataliya V.

    2017-06-01

    We review the current state of knowledge about aeolian sand transport and aeolian bedforms on planet Venus. This knowledge is limited by lack of observational data. Among the four planetary bodies of the Solar System with sufficient atmospheres in contact with solid surfaces, Venus has the densest atmosphere; the conditions there are transitional between those for terrestrial subaerial and subaqueous transport. The dense atmosphere causes low saltation threshold and short characteristic saltation length, and short scale length of the incipient dunes. A few lines of evidence indicate that the typical wind speeds exceed the saltation threshold; therefore, sand transport would be pervasive, if sand capable of saltation is available. Sand production on Venus is probably much slower than on the Earth; the major terrestrial sand sinks are also absent, however, lithification of sand through sintering is expected to be effective under Venus' conditions. Active transport is not detectable with the data available. Aeolian bedforms (transverse dunes) resolved in the currently available radar images occupy a tiny area on the planet; however, indirect observations suggest that small-scale unresolved aeolian bedforms are ubiquitous. Aeolian transport is probably limited by sand lithification causing shortage of saltation-capable material. Large impact events likely cause regional short-term spikes in aeolian transport by supplying a large amount of sand-size particles, as well as disintegration and activation of older indurated sand deposits. The data available are insufficient to understand whether the global aeolian sand transport occurs or not. More robust knowledge about aeolian transport on Venus is essential for future scientific exploration of the planet, in particular, for implementation and interpretation of geochemical studies of surface materials. High-resolution orbital radar imaging with local to regional coverage and desirable interferometric capabilities is the

  1. Effect of the coastal conservation due to beach nourishment of Totori sand dune coast

    OpenAIRE

    Y. Shibutani; Matsubara, Y.; Kuroiwa, M.

    2013-01-01

    Tottori Sand Dune Coast located at western part of Japan is a sandy beach with a length about 8km facing Sea of Japan. The coast has been eroded starting around 1940s and the beach nourishment project has been carried out to restore the shoreline since 2005 at Tottori Sand Dune Coast. In the project, the deposition sands at port and river mouth were transported to the erosional area and injected in the region of the offshore erosional area and the backshore area and the total volumes of the s...

  2. Effect of the Design Parameters on the Performance of Inner Recycling Continuous Sand Filter

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-qiang; WEN Qin-xue; Lü Bing-nan

    2002-01-01

    A novel integrated water treatment facility, innerrecycling continuous sand filter, is discussed. The theory of micro-flocculation is applied in the sand-washing circulation system with continuous filtration and backwashing. The design and operation parameters,which affect the performance of the filter, are discussed.The key design parameters are provided as follows:diameter of filter material is 0.7 to 1.0 mm, depth of filter bed is 0.6 m, filtration velocity is less than 12 m/h,ratio of gas to water is 9:11 and sand recycling rate is 2 to 4 mm/min.

  3. Lack of interaction between the behavioral effects of ketamine and benzodiazepines in mice.

    Science.gov (United States)

    Fidecka, Sylwia; Pirogowicz, Ewa

    2002-01-01

    The effect of co-administration of ketamine at the sub-effective dose with diazepam, chlordiazepoxide and clonazepam on their antinociceptive and protective efficacy against pentetrazole-induced seizures were studied in mice. Ketamine alone produces dose-dependent antinociception manifested as reduction in the number of writhing episodes evoked by acetic acid. In the writhing test, the antinociceptive effects of the threshold doses of diazepam, chlordiazepoxide or clonazepam were not changed by ketamine, whereas that of morphine was intensified by ketamine. In the hot plate test, slight antinociceptive effects of the threshold dose of diazepam, but not that of chlordiazepoxide (except the results at 120 min of observation), were significantly intensified by ketamine vs ketamine alone. Ketamine alone was able to protect mice, in the dose-related manner, against pentetrazole-induced seizures. The anticonvulsant effects of the threshold doses of diazepam, chlordiazepoxide and clonazepam were not changed by ketamine. These findings indicate that co-administration of ketamine (at the sub-effective dose) with diazepam, chlordiazepoxide and clonazepam (at non-effective doses) resulted in an intensification of neither antinociceptive nor protective effect against pentetrazole-induced seizures in mice. These data seem to indicate the lack of interaction between ketamine and benzodiazepines with respect to their antinociceptive and anticonvulsant efficacy.

  4. Effects of Fetal Exposure to Asian Sand Dust on Development and Reproduction in Male Offspring.

    Science.gov (United States)

    Yoshida, Seiichi; Ichinose, Takamichi; Arashidani, Keiichi; He, Miao; Takano, Hirohisa; Shibamoto, Takayuki

    2016-11-23

    In recent experimental studies, we reported the aggravating effects of Asian sand dust (ASD) on male reproduction in mice. However, the effects of fetal ASD exposure on male reproduction have not been investigated. The present study investigated the effects of fetal ASD exposure on reproduction in male offspring. Using pregnant CD-1 mice, ASD was administered intratracheally on days 7 and 14 of gestation, and the reproduction of male offspring was determined at 5, 10, and 15 weeks after birth. The secondary sex ratio was significantly lower in the fetal ASD-exposed mice than in the controls. Histologic examination showed partial vacuolation of seminiferous tubules in immature mice. Moreover, daily sperm production (DSP) was significantly less in the fetal ASD-exposed mice than in the controls. DSP in the fetal ASD-exposed mice was approximately 10% less than the controls at both 5 and 10 weeks. However, both the histologic changes and the DSP decrease were reversed as the mice matured. These findings suggest that ASD exposure affects both the fetal development and the reproduction of male offspring. In the future, it will be necessary to clarify the onset mechanisms of ASD-induced male fetus death and male reproductive disorders.

  5. Effect of modifying process on mechanical properties of EN AC-43300 silumin cast into sand moulds

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2009-07-01

    Full Text Available Significance of alloy modification in course of casting process is the most explicitly visible on example of Al-Si alloys. Broad application of these alloys in foundry industry has become possible after invention of a method which changes solidification form of Al-Si eutectic mixture. Such primarily thick, acicular shape of silicon crystals becomes changed into fine and compact structure due to introduction of a small quantity of modifier to liquid alloy. The paper presents an attempt of assessment of melting and modification with strontium effects on mechanical properties of EN AC-43300 alloy cast into sand moulds. Obtained results concern selection of optimal quantity of strontium additive in aspect of obtained mechanical properties (Rm, A5, KCV, HB. Effect of strontium additive on change of mechanical properties of the investigated alloy was presented in graphical form. Further investigations shall be connected with determination of an effect of strontium additive on mechanical properties of the alloy after solution heat treatment and ageing treatment.

  6. Effect of Annealing Treatment on Erosion-Corrosion of Zr-Based Bulk Metallic Glass in Saline-Sand Slurry

    Science.gov (United States)

    Ji, Xiulin; Shan, Yiping; Chen, Yueyue; Wang, Hui

    2016-06-01

    Bulk metallic glass (BMG) may be a good candidate to solve the erosion-corrosion (E-C) problems of marine pumps in sand-containing seawater. Since annealing treatment is an effective way to improve plasticity of BMGs, the effect of annealing treatment on E-C wear of Zr-based BMG in saline-sand slurry was investigated. All of the annealed BMG samples were crystallized and the quantity of (Zr, Cu) phase increased but that of Al4Cu9 phase decreased with the increase of annealing temperature from 360 to 480 °C. Accordingly, annealing treatment enhances plasticity of the as-cast BMG at the cost of hardness and corrosion resistance. Moreover, 480 °C annealed BMG sample possesses the highest hardness and the lowest corrosion current density in all of the annealed BMG samples. Using a slurry pot erosion tester, the E-C wear of the as-cast and annealed BMG samples was studied under different impingement angles, impact velocities, and concentrations in saline-sand slurry. With the improvement of plasticity, 480 °C annealed BMG sample exhibits the best E-C wear resistance under high impingement angle, high impact velocity, and high sand concentration.

  7. The opposition effect and its relationship to sediment density in BRDF measurements from the Algodones Sand Dunes System

    Science.gov (United States)

    Ambeau, Brittany; Bachmann, Charles M.; Griffo, Carrie; Harms, Justin; Myers, Emily; Badura, Gregory

    2016-09-01

    Density, particle size distribution, surface moisture, and mineral content are some important geophysical properties that affect the bi-directional reflectance factor (BRF) of particulate media such as sand. According to radiative transfer theory, several of these geophysical properties are known to directly affect the overall level of reflectance, as well as the functional form of the opposition effect, for homogeneous, particulate media.1 Most sands are composite, i.e. non-homogeneous, and do not follow the standard distributions (with approximate analytical solutions) for particle size. Therefore, conventional radiative transfer models need to be modified to account for the complex nature of sand. In this work, we examine the impact of density on the functional form of the opposition effect, and we show that differences in density are expressed in a characteristic way. The measurements are collected using the laboratory and field-deployable Goniometer of the Rochester Institute of Technology-Two (GRIT-T). And, the results are based on sediment samples collected from the Algodones Sand Dunes System in southeastern California during the NASA Algodones Dunes Field Experiment conducted in March 2015.

  8. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report first provides a description of the local community and economy near Sand Lake NWR. An analysis of current and proposed management strategies that could...

  9. Greater Sand Dunes interagency fire management plan : environmental assessment/assessment of effect

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment (EA) discusses three alternatives for the Greater Sand Dunes National Park and Preserve, Baca National Wildlife Refuge and...

  10. Source, route and effect of Asian sand dust on environment and the oceans

    Institute of Scientific and Technical Information of China (English)

    Kai Zhang; Fahe Chai; Renjian Zhang; Zhigang Xue

    2010-01-01

    We summarize in this overview achievements in current research frontiers in Asian sand dust with emphasis on the method for sand dust research,the sources of sand dust aerosols,emission of sand dust,mechanism of sand dust weather,chemical transformation during transport,and influences on climatic environment and oceans.Our main results show that most of Asian sand dust comes from Mongolia,the Gobi Desert,arid and semiarid desert areas in northwest China,which is divided into initial sources and enhanced sources.Half of the global production of dust originates from Asian dust source regions.Asian dust weather is so immense that it can cover a 5-7-day journey from the sources to the Korean Peninsula,Japan Islands,and the Pacific Ocean to even impact North America.Asian dust weather plays an active role in the biogeochemical cycles of trace elements in the mid-latitude Northern Hemisphere.

  11. Effects of Manufactured-sand on Dry Shrinkage and Creep of High-strength Concrete

    Institute of Scientific and Technical Information of China (English)

    ZHOU Mingkai; WANG Jiliang; ZHU Lide; HE Tusheng

    2008-01-01

    The influences of natural sand, manufactured-sand (MS) and stone-dust (SD) in the manufactured-sand on workability, compressive strength, elastic modulus, drying shrinkage and creep properties of high-strength concrete (HSC) were tested and compared. The results show that the reasonable content (7%-10.5%) of SD in MS will not deteriorate the workability of MS-HSC. It could even improve the workability. Moreover, the compressive strength increases gradually with the increasing SD content,and the MS-HSC with low SD content (smaller than 7%) has the elastic modulus which approaches that of the natural sand HSC, but the elastic modulus reduces when the SD content is high. The influence of the SD content on drying shrinkage performance of MS-HSC is closely related to the hydration age. The shrinkage rate of MS-HSC in the former 7 d age is higher than that of the natural sand HSC, but the difference of the shrinkage rate in the late age is not marked. Meanwhile the shrinkage rate reduces as the fly ash is added; the specific creep and creep coefficient of MS-HSC with 7% SD are close to those of the natural sand HSC.

  12. The effect of chemical, physical and enzymatic treatments on the dewatering of tar sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Theriault, Y.; Masliyah, J.H.; Fedorak, P.M.; Vazquez-Duhalt, R.; Gray, M.R. [University of Alberta, Edmonton, AB (Canada). Dept. of Chemical Engineering

    1995-09-01

    Fine tailings (with solids {lt} 106{mu}m) from hot-water extraction of the Athabasca tar sands were subjected to thermal, physical, chemical and enzymatic treatments in an attempt to modify the dewatering characteristics of the solid particles. A low-speed centrifuge at circa 1500 relative centrifugal force for 15 h was used to accelerate the sedimentation of the solids, and allowed comparison of the ultimate concentration of solids after the various treatments. Fine tailings were subjected to thermal treatment, sonication and modification of the water chemistry. Although the rate of sedimentation was affected by these treatments, the ultimate volume fraction of solids after centrifuging was about 0.3 (50-55 wt% solids). Extraction of the tailings to remove bitumen, humins and other organic components also failed to change the ultimate solids concentration. Oxidation of the organic material in the tailings by hydrogen peroxide in Fenton`s reagent, and enzymatic oxidation with lignin peroxidase, manganese peroxidase, cytochrome c, horseradish peroxidase and cowpea peroxidase gave no significant effect on the volume fraction of solids in the sediment after centrifugation. The observation that all of these treated samples gave an ultimate volume fraction of solids of about 0.3 indicated that bitumen, adsorbed organic matter and salts had little effect on the ultimate dewatering of tailings. 26 refs., 3 figs., 5 tabs.

  13. Effectiveness of Sand-Therapy on the Attenuation of Separation anxiety Signs in Pre-School Children

    Directory of Open Access Journals (Sweden)

    Arghavan Shariat

    2015-01-01

    Full Text Available Background and Objective: The present research was conducted with the aim of determining effect of Sand-therapy on the attenuation of separation anxiety signs among pre-school children in Isfahan, Iran. Methods: The statistical society consists of all pre-school children who had separation anxiety disorder and Among100 children, 30 persons were selected using available sampling. The method of this research is quasi-experimental with one group and pre-test and post-test plan. After performing pre-test of separation anxiety disorder scale, the experimental group were trained under sand-therapy training in 10 sessions of 60 minutes for a period of two months and after that, post-test of separation anxiety disorder scale was performed. The research tool consists of the questionnaire CSI-4 of child’s morbid signs. Wilcoxon method was used to analysis the results. Results: The research findings showed that there was a meaningful different (P=0.008 between pre- test & post-test scores of anxiety signs for study group.Conclusion: As a practical message, we can mention that sand therapy is as an interesting and practical playing for the children and it is a meaningful therapy related to attenuation of separation anxious signs.Keywords: Sand therapy, separation anxiety, pre-school-children

  14. Effects of full-scale beach renovation on fecal indicator levels in shoreline sand and water.

    Science.gov (United States)

    Hernandez, Rafael J; Hernandez, Yasiel; Jimenez, Nasly H; Piggot, Alan M; Klaus, James S; Feng, Zhixuan; Reniers, Ad; Solo-Gabriele, Helena M

    2014-01-01

    Recolonization of enterococci, at a non-point source beach known to contain high background levels of bacteria, was studied after a full-scale beach renovation project. The renovation involved importation of new exogenous sand, in addition to infrastructure improvements. The study's objectives were to document changes in sand and water quality and to evaluate the relative contribution of different renovation activities towards these changes. These objectives were addressed: by measuring enterococci levels in the sand and fecal indicator bacteria levels (enterococci and fecal coliform) in the water, by documenting sediment characteristics (mineralogy and biofilm levels), and by estimating changes in observable enterococci loads. Analysis of enterococci levels on surface sand and within sediment depth cores were significantly higher prior to beach renovation (6.3-72 CFU/g for each sampling day) when compared to levels during and after beach renovation (0.8-12 CFU/g) (P < 0.01). During the renovation process, sand enterococci levels were frequently below detection limits (<0.1 CFU/g). For water, exceedances in the regulatory thresholds that would trigger a beach advisory decreased by 40% for enterococci and by 90% for fecal coliform. Factors that did not change significantly between pre- and post- renovation included the enterococci loads from animals (approx. 3 × 10(11) CFU per month). Factors that were observed to change between pre- and post- renovation activities included: the composition of the beach sand (64% versus 98% quartz, and a significant decrease in biofilm levels) and loads from direct stormwater inputs (reduction of 3 × 10(11) CFU per month). Overall, this study supports that beach renovation activities contributed to improved sand and water quality resulting in a 50% decrease of observable enterococci loads due to upgrades to the stormwater infrastructure. Of interest was that the change in the sand mineralogy also coincided with changes in biofilm

  15. Simulation of effects of wastewater discharges on Sand Creek and lower Caddo Creek near Ardmore, Oklahoma

    Science.gov (United States)

    Wesolowski, Edwin A.

    1999-01-01

    A streamflow and water-quality model was developed for reaches of Sand and Caddo Creeks in south-central Oklahoma to simulate the effects of wastewater discharge from a refinery and a municipal treatment plant. The purpose of the model was to simulate condi tions during low streamflow when the conditions controlling dissolved-oxygen concentrations are most severe. Data collected to calibrate and verify the streamflow and water-quality model include continuously monitored streamflow and water-quality data at two gaging stations and three temporary monitoring stations; wastewater discharge from two wastewater plants; two sets each of five water-quality samples at nine sites during a 24-hour period; dye and propane samples; periphyton samples; and sediment oxygen demand measurements. The water-quality sampling, at a 6-hour frequency, was based on a Lagrangian reference frame in which the same volume of water was sampled at each site. To represent the unsteady streamflows and the dynamic water-quality conditions, a transport modeling system was used that included both a model to route streamflow and a model to transport dissolved conservative constituents with linkage to reaction kinetics similar to the U.S. Environmental Protection Agency QUAL2E model to simulate nonconservative constituents. These model codes are the Diffusion Analogy Streamflow Routing Model (DAFLOW) and the branched Lagrangian transport model (BLTM) and BLTM/QUAL2E that, collectively, as calibrated models, are referred to as the Ardmore Water-Quality Model. The Ardmore DAFLOW model was calibrated with three sets of streamflows that collectively ranged from 16 to 3,456 cubic feet per second. The model uses only one set of calibrated coefficients and exponents to simulate streamflow over this range. The Ardmore BLTM was calibrated for transport by simulating dye concentrations collected during a tracer study when streamflows ranged from 16 to 23 cubic feet per second. Therefore, the model is expected

  16. Measuring and modeling the effect of surface moisture on the spectral reflectance of coastal beach sand.

    Science.gov (United States)

    Nolet, Corjan; Poortinga, Ate; Roosjen, Peter; Bartholomeus, Harm; Ruessink, Gerben

    2014-01-01

    Surface moisture is an important supply limiting factor for aeolian sand transport, which is the primary driver of coastal dune development. As such, it is critical to account for the control of surface moisture on available sand for dune building. Optical remote sensing has the potential to measure surface moisture at a high spatio-temporal resolution. It is based on the principle that wet sand appears darker than dry sand: it is less reflective. The goals of this study are (1) to measure and model reflectance under controlled laboratory conditions as function of wavelength (λ) and surface moisture (θ) over the optical domain of 350-2500 nm, and (2) to explore the implications of our laboratory findings for accurately mapping the distribution of surface moisture under natural conditions. A laboratory spectroscopy experiment was conducted to measure spectral reflectance (1 nm interval) under different surface moisture conditions using beach sand. A non-linear increase of reflectance upon drying was observed over the full range of wavelengths. Two models were developed and tested. The first model is grounded in optics and describes the proportional contribution of scattering and absorption of light by pore water in an unsaturated sand matrix. The second model is grounded in soil physics and links the hydraulic behaviour of pore water in an unsaturated sand matrix to its optical properties. The optical model performed well for volumetric moisture content θ 0.97), but underestimated reflectance for θ between 24-30% (R2 > 0.92), most notable around the 1940 nm water absorption peak. The soil-physical model performed very well (R2 > 0.99) but is limited to 4% > θ < 24%. Results from a field experiment show that a short-wave infrared terrestrial laser scanner (λ = 1550 nm) can accurately relate surface moisture to reflectance (standard error 2.6%), demonstrating its potential to derive spatially extensive surface moisture maps of a natural coastal beach.

  17. Measuring and modeling the effect of surface moisture on the spectral reflectance of coastal beach sand.

    Directory of Open Access Journals (Sweden)

    Corjan Nolet

    Full Text Available Surface moisture is an important supply limiting factor for aeolian sand transport, which is the primary driver of coastal dune development. As such, it is critical to account for the control of surface moisture on available sand for dune building. Optical remote sensing has the potential to measure surface moisture at a high spatio-temporal resolution. It is based on the principle that wet sand appears darker than dry sand: it is less reflective. The goals of this study are (1 to measure and model reflectance under controlled laboratory conditions as function of wavelength (λ and surface moisture (θ over the optical domain of 350-2500 nm, and (2 to explore the implications of our laboratory findings for accurately mapping the distribution of surface moisture under natural conditions. A laboratory spectroscopy experiment was conducted to measure spectral reflectance (1 nm interval under different surface moisture conditions using beach sand. A non-linear increase of reflectance upon drying was observed over the full range of wavelengths. Two models were developed and tested. The first model is grounded in optics and describes the proportional contribution of scattering and absorption of light by pore water in an unsaturated sand matrix. The second model is grounded in soil physics and links the hydraulic behaviour of pore water in an unsaturated sand matrix to its optical properties. The optical model performed well for volumetric moisture content θ 0.97, but underestimated reflectance for θ between 24-30% (R2 > 0.92, most notable around the 1940 nm water absorption peak. The soil-physical model performed very well (R2 > 0.99 but is limited to 4% > θ < 24%. Results from a field experiment show that a short-wave infrared terrestrial laser scanner (λ = 1550 nm can accurately relate surface moisture to reflectance (standard error 2.6%, demonstrating its potential to derive spatially extensive surface moisture maps of a natural coastal beach.

  18. Effect of substitution of sand stone dust for quartz and clay in triaxial porcelain composition

    Indian Academy of Sciences (India)

    M K Haldar; S K Das

    2012-10-01

    Quartz and kaolin were partially substituted by sand stone dust (a siliceous byproduct of Indian stone cutting and polishing industries) in a traditional triaxial porcelain composition consisting of kaolin, quartz and feldsper. The effect of substitution upon heating at different temperatures (1050–1150°C) were studied by measuring the linear shrinkage, bulk density, porosity and flexural strength. Qualititative phase and microstructural analysis on selected samples were carried out using XRD and SEM/EDX technique. The results show that the samples of all the batches achieved higher density (2.50 g/cc) and almost full vitrification (<0.1% apparent porosity) at around 1115°C compared to around 1300°C for traditional triaxial porcelain composition. As high as 70 MPa flexural strength was obtained in most of the vitrified samples. No significant variation in physico-mechanical properties was observed in between the composition. XRD studies on selected samples show presence of mainly quartz phase both at low and high temperatures. SEM photomicrographs of the 1115°C heated specimen show presence of quartz grain and glassy matrix. Few quartz grains (20–40m) are associated with circumferential cracks around them.

  19. Effect of calcium phosphate addition on sintering of El-Oued sand quartz raw materials

    Directory of Open Access Journals (Sweden)

    L. Foughali

    2014-12-01

    Full Text Available This work addresses the development of an eventual low cost ceramic insulating or microfiltration membrane supports from inexpensive raw materials such Eloued quartz sand (EQS and calcium phosphate (CP using uniaxially dry compaction method. The prepared samples were sintered at different temperatures ranging between 1200 and 1550 ºC. Subsequently, the effects of sintering temperature and amount of CP on samples proprieties were investigated. It is observed that X-ray diffracion measurements confirmed that EQS was transformed into cristobalite and tridymite phases when both sintering temperature and holding time were increased. This transformation is favored with increasing amount of CP, it is observed also formation of CaSiO3 and Ca(Fe(AlPO4. The SEM images of the samples sintered at different temperatures illustrate that silica grains, CP grains, intergranular phase contents (Si, Ca, P, and O and an important open porosity depend on the sintering temperature. The porosity ratio changes in the range between 37% and 34% according to sintering temperature and to CP content; these values are in good agreement with SEM images. The thermal expansion behavior shows a weak expansion in the range of temperature between 600 and 1000 ºC which is situated between 1.27% and 1.33% (variation of 0.05% at 400 ºC.

  20. Effects of waste glass and waste foundry sand additions on reclaimed tiles containing sewage sludge ash.

    Science.gov (United States)

    Lin, Deng-Fong; Luo, Huan-Lin; Lin, Kuo-Liang; Liu, Zhe-Kun

    2017-07-01

    Applying sewage sludge ash (SSA) to produce reclaimed tiles is a promising recycling technology in resolving the increasing sludge wastes from wastewater treatment. However, performance of such reclaimed tiles is inferior to that of original ceramic tiles. Many researchers have therefore tried adding various industrial by-products to improve reclaimed tile properties. In this study, multiple materials including waste glass and waste foundry sand (WFS) were added in an attempt to improve physical and mechanical properties of reclaimed tiles with SSA. Samples with various combinations of clay, WFS, waste glass and SSA were made with three kiln temperatures of 1000°C, 1050°C, and 1100°C. A series of tests on the samples were next conducted. Test results showed that waste glass had positive effects on bending strength, water absorption and weight loss on ignition, while WFS contributed the most in reducing shrinkage, but could decrease the tile bending strength when large amount was added at a high kiln temperature. This study suggested that a combination of WFS from 10% to 15%, waste glass from 15% to 20%, SSA at 10% at a kiln temperature between 1000°C and 1050°C could result in quality reclaimed tiles with a balanced performance.

  1. Effects of Outer Membrane Proteins (OMPs) on the Transport of Escherichia coli within Saturated Sands

    Science.gov (United States)

    Xu, S.; Bardy, S.; Feriancikova, L.

    2012-12-01

    A thorough understanding of the transport behavior of bacteria within the groundwater system is critical to the protection of groundwater resources from microbial contamination and the reduction of associated public health risks. In this study, we used TolC and Ag43 positive and negative E. coli mutants to evaluate the effects of OMP TolC and Ag43 on the transport behavior of E. coli under a wide range of water chemistry conditions. The surface properties (e.g., zeta potential, contact angles of three probing liquid) of TolC and Ag43 positive and negative E. coli cells were determined and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, which considers Lifshitz-van der Waals (LW) interaction, the electrostatic double layer (EDL) interaction as well as the Lewis acid-base (AB) (i.e., hydrophobic) interaction between E. coli cells and the surface of quartz sands, were used to explain the observed trend in E. coli mobility. In general, good agreements between the experimental observations and XDLVO calculations were observed. Findings from this research suggested that OMPs could significantly impact bacterial mobility in sandy aquifers.

  2. EFFECTS OF A SAND RUNNING SURFACE ON THE KINEMATICS OF SPRINTING AT MAXIMUM VELOCITY

    Directory of Open Access Journals (Sweden)

    P E Alcaraz

    2011-05-01

    Full Text Available Performing sprints on a sand surface is a common training method for improving sprint-specific strength. For maximum specificity of training the athlete’s movement patterns during the training exercise should closely resemble those used when performing the sport. The aim of this study was to compare the kinematics of sprinting at maximum velocity on a dry sand surface to the kinematics of sprinting on an athletics track. Five men and five women participated in the study, and flying sprints over 30 m were recorded by video and digitized using biomechanical analysis software. We found that sprinting on a sand surface was substantially different to sprinting on an athletics track. When sprinting on sand the athletes tended to ‘sit’ during the ground contact phase of the stride. This action was characterized by a lower centre of mass, a greater forward lean in the trunk, and an incomplete extension of the hip joint at take-off. We conclude that sprinting on a dry sand surface may not be an appropriate method for training the maximum velocity phase in sprinting. Although this training method exerts a substantial overload on the athlete, as indicated by reductions in running velocity and stride length, it also induces detrimental changes to the athlete’s running technique which may transfer to competition sprinting.

  3. Effects of Asian sand dust particles on the respiratory and immune system.

    Science.gov (United States)

    Honda, Akiko; Matsuda, Yugo; Murayama, Rumiko; Tsuji, Kenshi; Nishikawa, Masataka; Koike, Eiko; Yoshida, Seiichi; Ichinose, Takamichi; Takano, Hirohisa

    2014-03-01

    Epidemiologic studies have reported that Asian sand dust (ASD) particles can affect respiratory health; however, the mechanisms remain unclear. We investigated the effects of ASD on airway epithelial cells and immune cells, and their contributing factors to the effects. Human airway epithelial cells were exposed to ASD collected on 1-3 May (ASD1) and on 12-14 May (ASD2) 2011 in Japan and heat-treated ASD1 for excluding heat-sensitive substances (H-ASD) at a concentration of 0, 3, 30 or 90 µg ml(-1) for 4 or 24 h. Furthermore, bone marrow-derived dendritic cells (BMDC) from atopic prone mice were differentiated by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) then these BMDC were exposed to the ASD for 24 h. Also splenocytes as mixture of immune cells were exposed to the ASD for 72 h. All ASD dose dependently reduced viability of airway epithelial cells. Non-heated ASD showed a dose-dependent increase in the protein release of interleukin (IL)-6 and IL-8. The raises induced by ASD1 were higher than those by ASD2. ASD1 and ASD2 also elevated ICAM-1 at the levels of mRNA, cell surface protein and soluble protein in culture medium. In contrast, H-ASD did not change most of these biomarkers. Non-heated ASD showed enhancement in the protein expression of DEC205 on BMDC and in the proliferation of splenocytes, whereas H-ASD did not. These results suggest that ASD affect airway epithelial cells and immune cells such as BMDC and splenocytes. Moreover, the difference in ASD events and components adhered to ASD can contribute to the health effects.

  4. Colonization of Phlebotomus papatasi changes the effect of pre-immunization with saliva from lack of protection towards protection against experimental challenge with Leishmania major and saliva.

    OpenAIRE

    Derbali Mohamed; Cherni Saifeddine; Chelbi Ifhem; Kaabi Belhassen; Ben Hadj Ahmed Sami; Laouini Dhafer; Zhioua Elyes

    2011-01-01

    Abstract Background Sand fly saliva has been postulated as a potential vaccine or as a vaccine component within multi component vaccine against leishmaniasis. It is important to note that these studies were performed using long-term colonized Phlebotomus papatasi. The effect of sand flies colonization on the outcome of Leishmania infection is reported. Results While pre-immunization of mice with salivary gland homogenate (SGH) of long-term colonized (F5 and beyond) female Phlebotomus papatasi...

  5. Effects of dynamic operating conditions on nitrification in biological rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Boe-Hansen, Rasmus; Musovic, Sanin

    2014-01-01

    Biological rapid sand filters are often used to remove ammonium from groundwater for drinking water supply. They often operate under dynamic substrate and hydraulic loading conditions, which can lead to increased levels of ammonium and nitrite in the effluent. To determine the maximum nitrification...... operating conditions. The ammonium removal rate of the filter was determined by the ammonium loading rate, but was independent of both the flow and influent ammonium concentration individually. Ammonia-oxidizing bacteria and archaea were almost equally abundant in the filter. Both ammonium removal...... rates and safe operating windows of rapid sand filters, a pilot scale rapid sand filter was used to test short-term increased ammonium loads, set by varying either influent ammonium concentrations or hydraulic loading rates. Ammonium and iron (flock) removal were consistent between the pilot...

  6. Effects of bacterial cells and two types of extracellular polymers on bioclogging of sand columns

    Science.gov (United States)

    Xia, Lu; Zheng, Xilai; Shao, Haibing; Xin, Jia; Sun, Zhaoyue; Wang, Leyun

    2016-04-01

    Microbially induced reductions in the saturated hydraulic conductivity, Ks, of natural porous media, conventionally called bioclogging, occurs frequently in natural and engineered subsurface systems. Bioclogging can affect artificial groundwater recharge, in situ bioremediation of contaminated aquifers, or permeable reactive barriers. In this study, we designed a series of percolation experiments to simulate the growth and metabolism of bacteria in sand columns. The experimental results showed that the bacterial cell amount gradually increased to a maximum of 8.91 log10 CFU/g sand at 144 h during the bioclogging process, followed by a decrease to 7.89 log10 CFU/g sand until 336 h. The same variation pattern was found for the concentration of tightly bound extracellular polymeric substances (TB-EPS), which had a peak value of 220.76 μg/g sand at 144 h. In the same experiments, the concentration of loosely bound extracellular polymeric substances (LB-EPS) increased sharply from 54.45 to 575.57 μg/g sand in 192 h, followed by a slight decline to 505.04 μg/g sand. The increase of the bacterial cell amount along with the other two concentrations could reduce the Ks of porous media, but their relative contributions varied to a large degree during different percolation stages. At the beginning of the tests (e.g., 48 h before), bacterial cells were likely responsible for the Ks reduction of porous media because no increase was found for the other two concentrations. With the accumulation of cells and EPS production from 48 to 144 h, both were important for the reduction of Ks. However, in the late period of percolation tests from 144 to 192 h, LB-EPS was probably responsible for the further reduction of Ks, as the bacterial cell amount and TB-EPS concentration decreased. Quantitative contributions of bacterial cell amount and the two types of extracellular polymers to Ks reductions were also evaluated.

  7. Informing disinvestment through cost-effectiveness modelling: is lack of data a surmountable barrier?

    Science.gov (United States)

    Karnon, Jonathan; Carlton, Jill; Czoski-Murray, Carolyn; Smith, Kevin

    2009-01-01

    The mandatory nature of recommendations made by the National Institute for Health and Clinical Excellence (NICE) in the UK has highlighted inherent difficulties in the process of disinvestment in existing technologies to fund NICE-approved technologies. A lack of evidence on candidate technologies means that the process of disinvestment is subject to greater uncertainty than the investment process, and inefficiencies may occur as a result of the inverse evidence law. This article describes a potential disinvestment scenario and the options for the decision maker, including the conduct of value of information analyses. To illustrate the scenario, an economic evaluation of a disinvestment candidate (screening for amblyopia and strabismus) is presented. Only very limited data were available. The reference case analysis found that screening is not cost effective at currently accepted values of a QALY. However, a small utility decrement due to unilateral vision loss reduced the incremental cost per QALY gained, with screening expected to be extremely cost effective. The discussion highlights the specific options to be considered by decision makers in light of the model-based evaluation. It is shown that the evaluation provides useful information to guide the disinvestment decision, providing a range of focused options with respect to the decision and the decision-making process. A combination of explicit model-based evaluation, and pragmatic and generalizable approaches to interpreting uncertainty in the decision-making process is proposed, which should enable informed decisions around the disinvestment of technologies with weak evidence bases.

  8. Experimental hypervelocity impact into quartz sand. II - Effects of gravitational acceleration

    Science.gov (United States)

    Gault, D. E.; Wedekind, J. A.

    1977-01-01

    Experimental results for craters formed by aluminum spheres impacting at normal incidence against quartz sand targets in gravitational acceleration environments ranging from 0.073 to 1.0 g (g = 980 cm/sq sec) are reported. Impact velocities varied from 0.4 to 8.0 km/sec. Crater dimensions and formation times are compared with results from a simplified dimensional analysis of the cratering processes. Although the comparison indicates a dominant role of gravity relative to the target strength for craters formed in sand, the results serve primarily to emphasize that both gravity and strength are variables of fundamental significance to cratering processes.

  9. 搭设障蔽控制樟子松风蚀沙埋危害的效果%Control Effect on Wind Erosion and Sand Cover by Building Sand-Barrier for Pinus sylvestris var.mongolica Plantation

    Institute of Scientific and Technical Information of China (English)

    屈升银; 叶竹林

    2011-01-01

    The control effect on wind erosion and sand cover by building sand-barrier was studied by taking Pinus sylvestris var. Mongolica as planting tree species. The results showed that building sand-barrier could promote the survival rate of the plantation up to 100% , which was significantly higher than that of the control. There were also significant differences in the growth rate of the Pinus sylvestris var. Mongolica plantation between building the sand-barrier and the control. The experiment showed that building the sand-barrier could promote the average sapling height, basal diameter and crown growth by 55.4% , 66. 6% and 60.1% respectively compared to the control. Sand-barrier building provided the morphology construction of the Pinus sylvestris var. Mongolica saplings with much better environment that significantly reduced the phenomena such as trunk bending, wind throw and drying up of the brnaches and turning yellow of the leaves due to the wind damage.%以樟子松为对象探讨搭设沙障控制风蚀沙埋危害的效果.结果表明:搭设与未搭设沙障的造林保存率存在显著差异,搭设沙障可使造林保存率高达100%;搭设与未搭设沙障的生长量也存在显著差异,搭设沙障可使树高、地径、树冠生长量分别提高55.4%、66.6%和60.7%;搭设沙障为樟子松的形态建成创造了良好的环境条件,树干弯曲、风倒及枯黄现象明显减少.

  10. Effects of Sand Dune and Vegetation in the Coastal Area of Sri Lanka at the Indian Ocean Tsunami

    Science.gov (United States)

    Tanaka, Norio; Sasaki, Yasushi; Mowjood, M. I. M.

    This study explored the effects of coastal vegetation and sand dune on tsunami protection based on field observations carried out after the Indian Ocean tsunami on December 26, 2004. The representative vegetation was classified into six types according to their habitat and the stand structures of the trees. The impact of vegetation structure on drag forces was analyzed using the observed characteristics of the tree species. The drag coefficient, including the vertical stand structures of the trees, Cd-all, and the vegetation thickness in a unit area, dNu (d: reference diameter of trees, Nu: number of trees per unit area), varied greatly with the species classification. Based on the field survey and data analysis, Rhizophora apiculata and Rhizophora mucronata (Rhizophora apiculata-type), kinds of mangroves, and Pandanus odoratissimus, representative tree that grows in beach sand, were found to be especially effective in providing protection from tsunami-damage due to their complex aerial root structures. The breaking moment of the trees was investigated through a pulling test for the representative trees. The threshold value for breaking moment was compared to the drag-force moment acting on the trees located at the tsunami-damaged site. The breaking moment equation represents well the limitation of the representative species with the tsunami height. It arrives at a hypothesis about which species could better withstand the effects of a tsunami wave. Sand dune and lagoon is a typical landscape in most part of the coastal zone of Sri Lanka. The combination of the sand dune followed by vegetation toward landside played an important role in retarding tsunami. Two layers of forest in the vertical direction with P. odoratissimus and Casuarina equisetifolia and a horizontal forest structure of small and large diameter trees were also important for increasing drag, trapping floating objects, broken branches, houses, and people. These information should be considered in

  11. Disturbance of the inclined inserting-type sand fence to wind-sand flow fields and its sand control characteristics

    Science.gov (United States)

    Cheng, Jian-jun; Lei, Jia-qiang; Li, Sheng-yu; Wang, Hai-feng

    2016-06-01

    The inclined inserting-type sand fence is a novel sand retaining wall adopted along the Lanxin High-Speed Railway II in Xinjiang for controlling and blocking sand movement. To verify the effectiveness of the new fence structure for sand prevention, a wind tunnel test was used for flow field test simulation of the sand fence. The results indicate that the inclined inserting-type sand fence was able to deflect the flow of the sand and was able to easily form an upward slant acceleration zone on the leeward side of the sand fence. As shown by the percentage change in sand collection rates on the windward side and the leeward side of the sand fence, the sand flux per unit area at 4 m height in the slant upward direction increased on the leeward side of the inclined inserting-type sand fence. By comparing the flow fields, this site is an acceleration zone, which also reaffirms the correspondence of wind-sand flow fields with the spatial distribution characteristic of the wind-carried sand motion. The field sand collection data indicates that under the effects of the inclined inserting-type sand fence, the sandy air currents passing in front and behind the sand fence not only changed in quality, but the grain composition and particle size also significantly changed, suggesting that the inclined inserting-type sand fence has a sorting and filtering effect on the sandy air currents that passed through. The fence retained coarse particulates on the windward side and fine particulates within the shade of the wind on the leeward side.

  12. Effects of Heterogeneous Adsorption Affinity on Natural Organic Matter (NOM) Transport in Laboratory Sand Columns

    Science.gov (United States)

    McInnis, D. P.; Bolster, D.; Maurice, P. A.

    2012-12-01

    Transport of reactive sorbing solutes through porous media is commonly quantified by implementing an effective retardation coefficient in the advection-dispersion equation (ADE), which describes dispersion in accordance with Fick's law. However, anomalous (non-Fickian) transport behavior can be observed in systems with heterogeneous retardation coefficients (Dentz & Castro, 2009). In such systems, the ADE is unable to reproduce the non-Fickian nature of plume shapes and breakthrough curves, motivating the development and application of alternative solute transport theories, such as the continuous time random walk (CTRW) or multi-rate mass transfer (MRMT). Heterogeneity in retardation coefficients in practice arises from variability in the geochemical properties controlling sorption-desorption kinetics between the solute and mineral surfaces. These distributions have been described in the context of heterogeneity of the porous medium, but to date little attention has been given to the potential role of a geochemically heterogeneous solute. In this work, we consider a system in which anomalous transport arises during the passage of natural organic matter (NOM), a polydisperse mixture of compounds derived from the breakdown of plants and microorganisms in the environment, through homogeneous laboratory sand columns. NOM solutions were passed through columns containing either hematite, corundum, or a naturally-coated quartz sand at a variety of pH and ionic strength conditions. Influent and effluent NOM concentration was measured as UV absorbance at 254 nm. The resulting breakthrough curves are non-Fickian, displaying power-law tailing at late times. Such curves cannot be predicted by the ADE model. Reactivity of NOM components is known to be related to their molecular weight (MW), which tends to be log-normally distributed in aquatic NOM isolates (Cabaniss et al., 2000). Low-MW compounds are more water-soluble, have a higher diffusion coefficient, and due to their

  13. Lack of additional effect of adjunct of assisted ventilation to pulmonary rehabilitation in mild COPD patients.

    Science.gov (United States)

    Bianchi, L; Foglio, K; Porta, R; Baiardi, R; Vitacca, M; Ambrosino, N

    2002-05-01

    Different modalities of assisted ventilation improve breathlessness and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the effects of the addition of assisted ventilation during exercise training on the outcome of a structured pulmonary rehabilitation programme (PRP) in COPD patients. Thirty-three male patients with stable COPD (mean (SD) forced expiratory volume in 1 s (FEV1) 44 (16) % pred), without chronic ventilatory failure, undergoing a 6-week multidisciplinary outpatient PRP including exercise training, were randomised to training during either mask proportional assist ventilation (PAV: 18 patients) or spontaneous breathing (SB: 15 patients). Assessment included exercise tolerance, dyspnoea, leg fatigue, and health-related quality of life (HRQL). Five out of 18 patients (28%) in the PAV group dropped out due to lack of compliance with the equipment. Both groups showed significant post-PRP improvements in exercise tolerance (peak work rate difference: 20 (95% Cl 2.4-37.6) and 14 (3.8% CI to 24.2) W in PAV and SB group, respectively), dyspnoea and leg fatigue, but not in HRQL, without any significant difference between groups. It is concluded that with the modality and in the patients assessed in this study assisted ventilation during training sessions included in a multidisciplinary PRP was not well tolerated by all patients and gave no additional physiological benefit in comparison with exercise training alone.

  14. Effects of ocean acidification on the swimming ability, development and biochemical responses of sand smelt larvae.

    Science.gov (United States)

    Silva, Cátia S E; Novais, Sara C; Lemos, Marco F L; Mendes, Susana; Oliveira, Ana P; Gonçalves, Emanuel J; Faria, Ana M

    2016-09-01

    Ocean acidification, recognized as a major threat to marine ecosystems, has developed into one of the fastest growing fields of research in marine sciences. Several studies on fish larval stages point to abnormal behaviours, malformations and increased mortality rates as a result of exposure to increased levels of CO2. However, other studies fail to recognize any consequence, suggesting species-specific sensitivity to increased levels of CO2, highlighting the need of further research. In this study we investigated the effects of exposure to elevated pCO2 on behaviour, development, oxidative stress and energy metabolism of sand smelt larvae, Atherina presbyter. Larvae were caught at Arrábida Marine Park (Portugal) and exposed to different pCO2 levels (control: ~600μatm, pH=8.03; medium: ~1000μatm, pH=7.85; high: ~1800μatm, pH=7.64) up to 15days, after which critical swimming speed (Ucrit), morphometric traits and biochemical biomarkers were determined. Measured biomarkers were related with: 1) oxidative stress - superoxide dismutase and catalase enzyme activities, levels of lipid peroxidation and DNA damage, and levels of superoxide anion production; 2) energy metabolism - total carbohydrate levels, electron transport system activity, lactate dehydrogenase and isocitrate dehydrogenase enzyme activities. Swimming speed was not affected by treatment, but exposure to increasing levels of pCO2 leads to higher energetic costs and morphometric changes, with larger larvae in high pCO2 treatment and smaller larvae in medium pCO2 treatment. The efficient antioxidant response capacity and increase in energetic metabolism only registered at the medium pCO2 treatment may indicate that at higher pCO2 levels the capacity of larvae to restore their internal balance can be impaired. Our findings illustrate the need of using multiple approaches to explore the consequences of future pCO2 levels on organisms.

  15. The effect of phylogenetically different bacteria on the fitness of Pseudomonas fluorescens in sand microcosms.

    Directory of Open Access Journals (Sweden)

    Olaf Tyc

    Full Text Available In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48 and a Gram-positive (Bacillus sp. V102 under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure.

  16. GPER1 in sand rat epididymis: Effects of seasonal variations, castration and efferent ducts ligation.

    Science.gov (United States)

    Menad, Rafik; Fernini, Meriem; Smaï, Souaâd; Bonnet, Xavier; Gernigon-Spychalowicz, Thérèse; Moudilou, Elara; Khammar, Farida; Exbrayat, Jean-Marie

    2017-08-01

    Estrogen plays a crucial role in regulating epididymal function and development. Estrogen signaling is mediated via two main receptors essentially involved in the genomic regulating pathway: ERα and ERβ. Recent studies revealed the contribution of a novel estrogen receptor involved in the non-genomic pathway: GPER1. This receptor belongs to the family of seven-transmembrane G-protein-coupled receptors and it triggers rapid cellular responses. Immuno-histochemical studies and Western Blot analyses were performed to investigate the GPER1 expression in the caput and cauda epididymis of free-ranging fat sand rats (Psammomys obesus) captured during the breeding and resting seasons. We also investigated the effect of castration (C), castration followed by testosterone treatment (C+T), and ligation of the efferent ducts (L). During the breeding season, a marked positive GPER1 immunoreactivity was detected in the cytoplasm of principal cells and basal cells; this signal persisted during the resting season, attenuated however, meanwhile the clear cells were not immuno-reactive. In C animals, the immuno-histochemical staining underwent nuclear translocation. In C+T animals, this response became nuclear and cytoplasmic. In the L group, the expression of the GPER1 was mainly located in the cytoplasm of principal cells and in the nuclei of basal cells; the sperm was also immune-positive in the cauda epididymis. Western blot analysis showed that GPER1 has a molecular weight of 55kDa in the caput and cauda epididymis during the breeding season, and it persisted during the resting season in the caput epididymis with a decrease in the cauda epididymis. These results suggest that GPER1 mediate a specific cellular estrogen signaling with marked differences between the breeding and resting seasons. Experimental groups suggest that testosterone is involved in the regulation of the expression of GPER1, in addition to other estrogen signalization pathways. Copyright © 2017 Elsevier B

  17. The effect of EDTA on the groundwater transport of thorium through sand.

    Science.gov (United States)

    May, Colin C; Young, Lindsay; Worsfold, Paul J; Heath, Sarah; Bryan, Nick D; Keith-Roach, Miranda J

    2012-10-01

    The effect of the anthropogenic complexing agent EDTA on thorium transport in groundwater has been studied using sand-packed columns and flow rates in the range of 20-100 m y⁻¹. The concentrations injected into the columns were in the range of 0.4-4 mM for Th and 4-40 mM for EDTA, and with EDTA:Th ratios in the range 1:1 to 10:1. The results show that EDTA can significantly increase Th transport, but two very different behaviours are observed at Th concentrations of 0.4 and 4 mM. At the lower concentration, Th breakthrough is retarded with respect to a conservative tracer, with a peak width that is consistent with a single K(d) value, followed by a longer tail, and the behaviour is very sensitive to the flow rate. However at 4 mM Th, the breakthrough peak appears near to that of the tracer, and the width of the peak is consistent with a distribution of K(d) values and/or a larger dispersivity than the tracer. Speciation and transport modelling have been used to interpret the data, and a model was developed that could explain the 0.4 mM behaviour. This suggests that ternary surface complexes are important in these systems, with at least two different species involved, although the complexity of Th speciation in these systems leads to significant uncertainty in the values of the equilibrium and kinetic parameters. For the 4 mM systems, the rapid transport observed could not be explained by a simple chemical model; instead it is likely that EDTA plays an important role in stabilising and transporting thorium colloids and clusters.

  18. The effect of phylogenetically different bacteria on the fitness of Pseudomonas fluorescens in sand microcosms.

    Science.gov (United States)

    Tyc, Olaf; Wolf, Alexandra B; Garbeva, Paolina

    2015-01-01

    In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48) and a Gram-positive (Bacillus sp. V102) under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure.

  19. Effect of Lures and Trap Placement on Sand Fly and Mosquito Traps

    Science.gov (United States)

    2008-01-01

    Phlebotomus guggisbergi, a vector of Leishmania tropica in Kenya. Med. Vet. Entomol. 7:216-218. Killick-Kendrick, R. 1999. The biology and control...Acta Tropica 101:106-114. Hoel, D.E, Butler, J.F., Fawaz, E.Y., Watany, N., El-Hossary, S.S., and Villinski, J. 2007. Response of phlebotomine sand

  20. Plant-feeding nematodes in coastal sand dunes: occurrence, host specificity and effects on plant growth

    NARCIS (Netherlands)

    Brinkman, E.P.; Duyts, H.; Karssen, G.; Stoel, C.D.; Putten, van der W.H.

    2015-01-01

    Aims Coastal sand dunes have a well-established abiotic gradient from beach to land and a corresponding spatial gradient of plant species representing succession in time. Here, we relate the distribution of plant-feeding nematodes with dominant plant species in the field to host specialization and

  1. The effects of surfactants and solution chemistry on the transport of multiwalled carbon nanotubes in quartz sand-packed columns.

    Science.gov (United States)

    Lu, Yinying; Xu, Xiaopan; Yang, Kun; Lin, Daohui

    2013-11-01

    The effect of different surfactants on the transport of multiwalled carbon nanotubes (MWCNTs) in quartz sand-packed columns was firstly investigated under various conditions. The stable plateau values (C(max)) of the breakthrough curves (BTCs), critical PVs (the number of pore volumes of infusions needed to reach the C(max)), maximum transport distances (L(max)), deposition rate coefficients (kd) and retention rates were calculated to compare the transport and retention of MWCNTs under various conditions. Stability of the MWCNT suspensions as a function of the influencing factors was examined to reveal the underlying mechanism of the MWCNT retention. Results showed that MWCNTs suspended by different surfactants presented different BTCs; the MWCNT transport increased with increasing sand size and MWCNT concentration; high flow velocity was favorable for the MWCNT transport, while high Ca(2+) concentration and low pH were unfavorable for the transport; hetero-aggregation, straining and site blocking occurred during the transport.

  2. Haulage Vehicle Traffic and Runoff Effect on Gully Growth on Roadside Slopes of Unpaved Sand-Quarry Road, Uyo.

    Directory of Open Access Journals (Sweden)

    Obot Ekpo Essien

    2013-10-01

    Full Text Available Rainfall runoff and sand haulage truck traffic count were quantified and regressed on gully soil loss and gully morphometric volume growth on unpaved haulage roadside erosion. The gully erosion on unpaved roadside was accelerated by the agency of runoff in splash wash from the road, and high axle sand haulage trucks traffic. The effect of the Runoff discharge and traffic count, as independent variables and cumulativequantities, on the cumulative soil loss from jagged side slope gullies, and the gully volume growth were very significant at P < 0.01 generally. Predictive coefficient of determination, significant at P < 0.01, were very perfect at R2= 88.8 to 98.9%. Different regimes of association were obtained such as: high runoff and high traffic count; high flow rate and low traffic count, and low runoff and high traffic count for effect and on gully loss and gully volume growth, and they gave accurate and significant relationship. Regulation of sand-mining over a catchment is recommended as it has otherwise destroyed landform and initiated unrestrained gullying.

  3. Liquefaction Resistance of Chlef River Silty Sand: Effect of Low Plastic Fines and other Parameters

    Directory of Open Access Journals (Sweden)

    Tom Schanz

    2010-07-01

    Full Text Available Silty sands are the most common type of soil that could be involved in both staticand earthquake-induced liquefaction. Most of the recent earthquakes have revealed theliquefaction of silty sands. Therefore, the selection of the appropriate undrained residualshear strength of liquefied soils to be used in the assessment of the post-liquefactionstability of earth dams and other earth structures is becoming a major challenge. A seriesof undrained monotonic and cyclic triaxial tests were carried out on reconstituted saturatedsamples of sand with variation in the fines content ranging from 0 to 50% for themonotonic tests and from 0 to 40% for the cyclic ones, in order to study the influence offines fraction and other parameters on the undrained residual shear strength andliquefaction potential of loose, medium dense and dense silty sand samples (Dr = 12%,50%, 60% and 90%. The results of the monotonic tests show that the stress-strain responseand shear strength behaviour is controlled by the percentage of fines fraction and thesamples become contractive for the studied relative densities (Dr = 12% and 90%. The undrained residual shear strength decreases as the global void ratio decreases and thefines content increases up to 30% fines content. Beyond that, it decreases with increasingthe global void ratio and the fines content. Moreover, the undrained residual strengthdecreases linearly as the fines content and the inter-granular void ratio increase. Cyclictest results show that the increase of the fines fraction accelerates the liquefactionphenomenon for the studied amplitude and the liquefaction resistance decreases with theincrease of the global void ratio and the loading amplitude. We notice that the reduction inthe liquefaction resistance of Chlef sand-silt mixtures becomes very marked for the smallercyclic stress ratios CSR = 0.15 and 0.25.

  4. Effects of sand burial on dew deposition on moss soil crust in a revegetated area of the Tennger Desert, Northern China

    Science.gov (United States)

    Jia, Rong-liang; Li, Xin-rong; Liu, Li-chao; Pan, Yan-xia; Gao, Yan-hong; Wei, Yong-ping

    2014-11-01

    Sand burial and dew deposition are two fundamental phenomena profoundly influencing biological soil crusts in desert areas. However, little information is available regarding the effects of sand burial on dew deposition on biological soil crusts in desert ecosystems. In this study, we evaluated the effects of sand burial at depths of 0 (control), 0.5, 1, 2 and 4 mm on dew formation and evaporation of three dominant moss crusts in a revegetated area of the Tengger Desert (Northern China) in 2010. The results revealed that sand burial significantly decreased the amount of dew deposited on the three moss crust types by acting as a semi-insulator retarding the dew formation and evaporation rates. The changes in surface temperature cannot fully explain the variations of the formation and evaporation rates of dew by moss crusts buried by sand. The extension of dew retention time was reflected by the higher dew ratios (the ratio of dew amount at a certain time to the maximum value in a daily course) in the daytime, and may to some extent have acted as compensatory mechanisms that diminished the negative effects of the reduction of dew amount induced by sand burial of moss crusts. The resistances to reduction of dewfall caused by sand burial among the three moss crusts were also compared and it was found that Bryum argenteum crust showed the highest tolerance, followed by crusts dominated by Didymodon vinealis and Syntrichia caninervis. This sequence corresponds well with the successional order of the three moss crusts in the revegetated area, thereby suggesting that resistance to reduction of dewfall may act as one mechanism by which sand burial drives the succession of moss crusts in desert ecosystems. This side effect of dew reduction induced by sand burial on biological soil crusts should be considered in future ecosystem construction and management of desert area.

  5. The Effect of Degree of Saturation of Sand on Detonation Phenomena Associated with Shallow-Buried and Ground-Laid Mines

    Directory of Open Access Journals (Sweden)

    M. Grujicic

    2006-01-01

    Full Text Available A new materials model for sand has been developed in order to include the effects of the degree of saturation and the deformation rate on the constitutive response of this material. The model is an extension of the original compaction materials model for sand in which these effects were neglected. The new materials model for sand is next used, within a non-linear-dynamics transient computational analysis, to study various phenomena associated with the explosion of shallow-buried and ground-laid mines. The computational results are compared with the corresponding experimental results obtained through the use of an instrumented horizontal mine-impulse pendulum, pressure transducers buried in sand and a post-detonation metrological study of the sand craters. The results obtained suggest that the modified compaction model for sand captures the essential features of the dynamic behavior of sand and accounts reasonably well for a variety of the experimental findings related to the detonation of shallow-buried or ground-laid mines.

  6. Effects of sand burial on biomass, chlorophyll fluorescence and extracellular polysaccharides of man-made cyanobacterial crusts under experimental conditions

    Institute of Scientific and Technical Information of China (English)

    WANG WeiBo; YANG CuiYun; TANG DongShan; LI DunHai; LIU YongDing; HU ChunXiang

    2007-01-01

    Soil cyanobacterial crusts occur throughout the world, especially in the semiarid and arid regions. It always encounters sand burial, which is an important feature of mobile sand dunes. A greenhouse study was conducted to determine the effects of sand burial on biomass, chlorophyll fluorescence andextracellular polysaccharides of man-made cyanobacterial crusts in six periods of time (0, 5, 10, 15, 20 and 30 d after burying) and at five depths (0, 0.2, 0.5, 1 and 2cm). The results indicated that with the increase of the burial time and burial depth extracellular polysaccharides content and Fv/Fm decreased correspondingly and there were no significant differences between 20 and 30 burial days under different burial depths. The degradation of chlorophyll a content appeared only at 20 and 30 burial days and there was also no significant difference between them under different burial depths. It was also observed a simultaneous decrease of the values of the Fv/Fm and the content of extracellular polysaccharides happened in the crusted cyanobacterium Microcoleus vaginatus Gom. It may suggest that there exists a relationship between extracellular polysaccharides and recovery of the activity of photosystem Ⅱ (PS Ⅱ) after rehydration.

  7. Effects of laser energy density on forming accuracy and tensile strength of selective laser sintering resin coated sands

    Institute of Scientific and Technical Information of China (English)

    Xu Zhifeng; Liang Pei; Yang Wei; Li Sisi; Cai Changchun

    2014-01-01

    Baozhu sand particles with size between 75 μm and 150 μm were coated by resin with the ratio of 1.5 wt.% of sands. Laser sintering experiments were carried out to investigate the effects of laser energy density (E =P/v), with different laser power (P) and scanning velocity (v), on the dimensional accuracy and tensile strength of sintered parts. The experimental results indicate that with the constant scanning velocity, the tensile strength of sintered samples increases with an increase in laser energy density; while the dimensional accuracy apparently decreases when the laser energy density is larger than 0.032 J·mm-2. When the laser energy density is 0.024 J·mm-2, the tensile strength shows no obvious change; but when the laser energy density is larger than 0.024 J·mm-2, the sample strength is featured by the initial increase and subsequent decrease with simultaneous increase of both laser power and scanning velocity. In this study, the optimal energy density range for laser sintering is 0.024-0.032 J·mm-2. Moreover, samples with the best tensile strength and dimensional accuracy can be obtained whenP = 30-40 W andv = 1.5-2.0 m·s-1. Using the optimized laser energy density, laser power and scanning speed, a complex coated sand mould with clear contour and excelent forming accuracy has been successfuly fabricated.

  8. Sands styrke

    DEFF Research Database (Denmark)

    Jacobsen, H. Moust; Jørgensen, Mogens B.; Poulsen, H. Serup

    1975-01-01

    På grundlag af triaxialforsøg med D=7 og 20 cm og varierende højde på løse og faste lejringer af Blokhussand kan effekten af varierende højde-breddeforhold og spændingsniveau samt skalaeffekten bestemmes. Ved sammenligning med pladeforsøg med overfladelast op til 8 t/m2 kan den almindelige fremga...... fremgangsmåde ved bæreevneberegninger på sand undersøges....

  9. Effects of sedimentation on soil physical and chemical properties and vegetation characteristics in sand dunes at the Southern Dongting Lake region, China

    Science.gov (United States)

    Pan, Ying; Zhang, Hao; Li, Xu; Xie, Yonghong

    2016-11-01

    Sedimentation is recognized as a major factor determining the ecosystem processes of lake beaches; however, the underlying mechanisms, especially in freshwater sand dunes, have been insufficiently studied. To this end, nine belt transects from nine freshwater sand dunes, classified into low (28.1 m) based on their elevations in 1972, were sampled to investigate differences in sedimentation rate and soil and vegetation characteristics in Southern Dongting Lake, China. Sedimentation rate, soil sand content, and soil pH increased, whereas soil clay, fine silt, moisture (MC), organic matter (OM), total N, and total K content, in addition to the growth and biodiversity of sand dune plants generally decreased with decreasing belt transect elevation. Regression analyses revealed that the negative effects of sedimentation on the ecosystem functions of sand dunes could be attributed to higher fine sand content in deposited sediments and stronger inhibition of plant growth. These results are consistent with previous studies performed in coastal sand dunes, which highlights the importance of sedimentation in determining ecological processes.

  10. Improvements in Sand Mold/Core Technology: Effects on Casting Finish

    Energy Technology Data Exchange (ETDEWEB)

    Prof. John J. Lannutti; Prof. Carroll E. Mobley

    2005-08-30

    In this study, the development and impact of density gradients on metal castings were investigated using sand molds/cores from both industry and from in-house production. In spite of the size of the castings market, almost no quantitative information about density variation within the molds/cores themselves is available. In particular, a predictive understanding of how structure and binder content/chemistry/mixing contribute to the final surface finish of these products does not exist. In this program we attempted to bridge this gap by working directly with domestic companies in examining the issues of surface finish and thermal reclamation costs resulting from the use of sand molds/cores. We show that these can be substantially reduced by the development of an in-depth understanding of density variations that correlate to surface finish. Our experimental tools and our experience with them made us uniquely qualified to achieve technical progress.

  11. Experimental Investigation of Temperature Effects on Microparticle Sand Rebound Characteristics at Gas Turbine Representative Conditions

    OpenAIRE

    Delimont, Jacob M

    2014-01-01

    When a gas turbine operates in a particle laden environment, such as a desert, small solid particles are ingested into the engine. The ingested sand particles can cause damage to engine components and reduce the service life of the engine. Particle ingestion causes the erosion of metal blades and vanes, and, if the firing temperature is hot enough, deposition of molten particles in the hot sections of the engine. Both deposition and erosion phenomena can severely reduce overall engine perfo...

  12. Effect of carbon nanotubes upon emissions from cutting and sanding carbon fiber-epoxy composites

    Science.gov (United States)

    Heitbrink, William A.; Lo, Li-Ming

    2015-08-01

    Carbon nanotubes (CNTs) are being incorporated into structural composites to enhance material strength. During fabrication or repair activities, machining nanocomposites may release CNTs into the workplace air. An experimental study was conducted to evaluate the emissions generated by cutting and sanding on three types of epoxy-composite panels: Panel A containing graphite fibers, Panel B containing graphite fibers and carbon-based mat, and Panel C containing graphite fibers, carbon-based mat, and multi-walled CNTs. Aerosol sampling was conducted with direct-reading instruments, and filter samples were collected for measuring elemental carbon (EC) and fiber concentrations. Our study results showed that cutting Panel C with a band saw did not generate detectable emissions of fibers inspected by transmission electron microscopy but did increase the particle mass, number, and EC emission concentrations by 20-80 % compared to Panels A and B. Sanding operation performed on two Panel C resulted in fiber emission rates of 1.9 × 108 and 2.8 × 106 fibers per second (f/s), while no free aerosol fibers were detected from sanding Panels A and B containing no CNTs. These free CNT fibers may be a health concern. However, the analysis of particle and EC concentrations from these same samples cannot clearly indicate the presence of CNTs, because extraneous aerosol generation from machining the composite epoxy material increased the mass concentrations of the EC.

  13. Effect of carbon nanotubes upon emissions from cutting and sanding carbon fiber-epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Heitbrink, William A. [LMK OSH Consulting LLC (United States); Lo, Li-Ming, E-mail: LLo@cdc.gov [Centers for Disease Control and Prevention (CDC), Division of Applied Research and Technology, National Institute for Occupational Safety and Health (NIOSH) (United States)

    2015-08-15

    Carbon nanotubes (CNTs) are being incorporated into structural composites to enhance material strength. During fabrication or repair activities, machining nanocomposites may release CNTs into the workplace air. An experimental study was conducted to evaluate the emissions generated by cutting and sanding on three types of epoxy-composite panels: Panel A containing graphite fibers, Panel B containing graphite fibers and carbon-based mat, and Panel C containing graphite fibers, carbon-based mat, and multi-walled CNTs. Aerosol sampling was conducted with direct-reading instruments, and filter samples were collected for measuring elemental carbon (EC) and fiber concentrations. Our study results showed that cutting Panel C with a band saw did not generate detectable emissions of fibers inspected by transmission electron microscopy but did increase the particle mass, number, and EC emission concentrations by 20–80 % compared to Panels A and B. Sanding operation performed on two Panel C resulted in fiber emission rates of 1.9 × 10{sup 8} and 2.8 × 10{sup 6} fibers per second (f/s), while no free aerosol fibers were detected from sanding Panels A and B containing no CNTs. These free CNT fibers may be a health concern. However, the analysis of particle and EC concentrations from these same samples cannot clearly indicate the presence of CNTs, because extraneous aerosol generation from machining the composite epoxy material increased the mass concentrations of the EC.

  14. Effects of ocean acidification on the swimming ability, development and biochemical responses of sand smelt larvae

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cátia S.E. [MARE — Marine and Environmental Sciences Centre, ISPA − Instituto Universitário (Portugal); MARE — Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria (Portugal); Novais, Sara C.; Lemos, Marco F.L.; Mendes, Susana [MARE — Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria (Portugal); Oliveira, Ana P. [IPMA — Instituto Português do Mar e da Atmosfera, Algés (Portugal); Gonçalves, Emanuel J. [MARE — Marine and Environmental Sciences Centre, ISPA − Instituto Universitário (Portugal); Faria, Ana M., E-mail: afaria@ispa.pt [MARE — Marine and Environmental Sciences Centre, ISPA − Instituto Universitário (Portugal)

    2016-09-01

    Ocean acidification, recognized as a major threat to marine ecosystems, has developed into one of the fastest growing fields of research in marine sciences. Several studies on fish larval stages point to abnormal behaviours, malformations and increased mortality rates as a result of exposure to increased levels of CO{sub 2}. However, other studies fail to recognize any consequence, suggesting species-specific sensitivity to increased levels of CO{sub 2}, highlighting the need of further research. In this study we investigated the effects of exposure to elevated pCO{sub 2} on behaviour, development, oxidative stress and energy metabolism of sand smelt larvae, Atherina presbyter. Larvae were caught at Arrábida Marine Park (Portugal) and exposed to different pCO{sub 2} levels (control: ~ 600 μatm, pH = 8.03; medium: ~ 1000 μatm, pH = 7.85; high: ~ 1800 μatm, pH = 7.64) up to 15 days, after which critical swimming speed (U{sub crit}), morphometric traits and biochemical biomarkers were determined. Measured biomarkers were related with: 1) oxidative stress — superoxide dismutase and catalase enzyme activities, levels of lipid peroxidation and DNA damage, and levels of superoxide anion production; 2) energy metabolism — total carbohydrate levels, electron transport system activity, lactate dehydrogenase and isocitrate dehydrogenase enzyme activities. Swimming speed was not affected by treatment, but exposure to increasing levels of pCO{sub 2} leads to higher energetic costs and morphometric changes, with larger larvae in high pCO{sub 2} treatment and smaller larvae in medium pCO{sub 2} treatment. The efficient antioxidant response capacity and increase in energetic metabolism only registered at the medium pCO{sub 2} treatment may indicate that at higher pCO{sub 2} levels the capacity of larvae to restore their internal balance can be impaired. Our findings illustrate the need of using multiple approaches to explore the consequences of future pCO{sub 2} levels on

  15. Lack of effective communication between communities and hospitals in Uganda: a qualitative exploration of missing links

    Directory of Open Access Journals (Sweden)

    Mutebi Aloysius

    2009-08-01

    Full Text Available Abstract Background Community members are stakeholders in hospitals and have a right to participate in the improvement of quality of services rendered to them. Their views are important because they reflect the perspectives of the general public. This study explored how communities that live around hospitals pass on their views to and receive feedback from the hospitals' management and administration. Methods The study was conducted in eight hospitals and the communities around them. Four of the hospitals were from three districts from eastern Uganda and another four from two districts from western Uganda. Eight key informant interviews (KIIs were conducted with medical superintendents of the hospitals. A member from each of three hospital management boards was also interviewed. Eight focus group discussions (FGDs were conducted with health workers from the hospitals. Another eight FGDs (four with men and four with women were conducted with communities within a five km radius around the hospitals. Four of the FGDs (two with men and two with women were done in western Uganda and the other four in eastern Uganda. The focus of the KIIs and FGDs was exploring how hospitals communicated with the communities around them. Analysis was by manifest content analysis. Results Whereas health unit management committees were supposed to have community representatives, the representatives never received views from the community nor gave them any feed back from the hospitals. Messages through the mass media like radio were seen to be non specific for action. Views sent through suggestion boxes were seen as individual needs rather than community concerns. Some community members perceived they would be harassed if they complained and had reached a state of resignation preferring instead to endure the problems quietly. Conclusion There is still lack of effective communication between the communities and the hospitals that serve them in Uganda. This deprives the

  16. Effect of texture and blasting pressure on residual stress and surface modifications in wet sand blasted α-Al2O3 coating

    OpenAIRE

    Ekström, Erik

    2015-01-01

    Recently, wet sand blasting on coated cutting tool inserts has drawn interest to the tooling industry due to its positive effects on cutting performance and tool life. This performance boost has partly been attributed to the buildup of compressive residual stresses in the coating during the blasting process. However, the mechanism of forming residual stresses in ceramic coatings during sand blasting is not fully understood. This work utilize x-ray diffraction as the main tool to study the for...

  17. Tar sand

    Energy Technology Data Exchange (ETDEWEB)

    McLendon, T.R.; Bartke, T.C.

    1990-01-01

    Research on tar sand is briefly discussed. The research program supported by the US Department of Energy (DOE) includes a variety of surface extraction schemes. The University of Utah has process development units (PDU) employing fluidized bed, hot, water-assisted, and fluidized-bed/heat-pipe, coupled combustor technology. Considerable process variable test data have been gathered on these systems: (1) a rotary kiln unit has been built recently; (2) solvent extraction processing is being examined; and (3) an advanced hydrogenation upgrading scheme (hydropyrolysis) has been developed. The University of Arkansas, in collaboration with Diversified Petroleum, Inc., has been working on a fatty acid, solvent extraction process. Oleic acid is the solvent/surfactant. Solvent is recovered by adjusting processing fluid concentrations to separate without expensive operations. Western Research Institute has a PDU-scale scheme called the Recycle Oil Pyrolysis and Extraction (ROPE) process, which combines solvent (hot recycle bitumen) and pyrolytic extraction. 14 refs., 19 figs.

  18. Enhanced flushing of polychlorinated biphenyls contaminated sands using surfactant foam: effect of partition coefficient and sweep efficiency.

    Science.gov (United States)

    Wang, Hao; Chen, Jiajun

    2012-01-01

    Foam flushing is an in situ soil remediation technology based on the traditional surfactant flushing method. The contribution of mobility control to contaminant removal by foam is helpful for improving this technology. Foam flushing of polychlorinated biphenyl (PCB)-contaminated unconsolidated media was performed to evaluate the effect of the partition coefficient (PC) and sweep efficiency (SE) on PCB removal. Column flushing with surfactant solution and foam with different types and concentrations of surfactant was carried out for PCB removal. Two types of quartz sand were investigated to evaluate the Jamin effect on the SE value of the washing agent. The results demonstrate that a small PC value and large SE value are necessary to achieve high PCB removal for foam flushing. Compared with solution flushing, the introduction of foam can effectively control the mobility of the washing agent. Similar to solution flushing, solubilization is a key factor which dominates the removal of PCBs in foam flushing. In addition, the SE value and PCB removal by foam flushing is less affected by particle size. Therefore, foam flushing was proved to be more effective in porous media with low hydraulic conductivity and high porosity. An integrated flushing with water, surfactant solution and foam was performed and the results prove that this technology successfully combines the advantages of solution solubilization and mobility control by foam, and thus further increases the remediation efficiency of PCBs to 94.7% for coarse sand.

  19. Enhanced flushing of polychlorinated biphenyls contaminated sands using surfactant foam: Effect of partition coefficient and sweep efficiency

    Institute of Scientific and Technical Information of China (English)

    Hao Wang; Jiajun Chen

    2012-01-01

    Foam flushing is an in situ soil remediation technology based on the traditional surfactant flushing method.The contribution of mobility control to contaminant removal by foam is helpful for improving this technology.Foam flushing of polychlorinated biphenyl (PCB)-contaminated unconsolidated media was performed to evaluate the effect of the partition coefficient (PC) and sweep efficiency (SE) on PCB removal.Column flushing with surfactant solution and foam with different types and concentrations of surfactant was carried out for PCB removal.Two types of quartz sand were investigated to evaluate the Jamin effect on the SE value of the washing agent.The results demonstrate that a small PC value and large SE value are necessary to achieve high PCB removal for foam flushing.Compared with solution flushing,the introduction of foam can effectively control the mobility of the washing agent.Similar to solution flushing,solubilization is a key factor which dominates the removal of PCBs in foam flushing.In addition,the SE value and PCB removal by foam flushing is less affected by particle size.Therefore,foam flushing was proved to be more effective in porous media with low hydraulic conductivity and high porosity.An integrated flushing with water,surfactant solution and foam was performed and the results prove that this technology successfully combines the advantages of solution solubilization and mobility control by foam,and thus further increases the remediation efficiency of PCBs to 94.7% for coarse sand.

  20. Heterogeneity of Rapid Sand Filters and Its Effect on Contaminant Transport and Nitrification Performance

    DEFF Research Database (Denmark)

    Lopato, Laure Rose; Galaj, Zofia; Delpont, Sébastien

    2011-01-01

    dispersivity of more than 33% in the 116 h after the start of filtration with a constant pore-water velocity and a zero-order nitrification rate of 9 mgN=L=h. The full-scale experiments showed that the rapid sand filter was heterogeneous with pore-water velocities ranging from 2.2 to 3:3 m=h for the same inlet...... flow. A first-order nitrification reaction with spatially variable pore-water velocity could be interpreted as a zero-order reaction with a constant pore-water velocity. A model demonstrated that filter heterogeneity could result in higher filter outlet ammonium concentrations....

  1. Effects of plasma treatment and sanding process on surface roughness of wood veneers

    OpenAIRE

    2014-01-01

    An ideal veneer surface is crucial for good panel properties in plywood manufacturing. The aim of this study was to compare plasma treatments and sanding (mechanical) processes with respect to the surface roughness of veneers. Rotary-cut veneers with a thickness of 2 mm from Scots pine (Pinus sylvestris) logs were used as material. After rotary peeling, veneer sheets were dried at 110 °C in a veneer dryer. Veneer sheets were divided into 4 main groups. The surfaces of the control veneer sheet...

  2. Effects of Building a Sand Barrier Berm to Mitigate the Effects of the Deepwater Horizon Oil Spill on Louisiana Marshes

    Science.gov (United States)

    Lavoie, Dawn; Flocks, James G.; Kindinger, Jack G.; Sallenger, A.H.; Twichell, David C.

    2010-01-01

    The State of Louisiana requested emergency authorization on May 11, 2010, to perform spill mitigation work on the Chandeleur Islands and on all the barrier islands from Grand Terre Island eastward to Sandy Point to enhance the capability of the islands to reduce the movement of oil from the Deepwater Horizon oil spill to the marshes. The proposed action-building a barrier berm (essentially an artificial island fronting the existing barriers and inlets) seaward of the existing barrier islands and inlets-'restores' the protective function of the islands but does not alter the islands themselves. Building a barrier berm to protect the mainland wetlands from oil is a new strategy and depends on the timeliness of construction to be successful. Prioritizing areas to be bermed, focusing on those areas that are most vulnerable and where construction can be completed most rapidly, may increase chances for success. For example, it may be easier and more efficient to berm the narrow inlets of the coastal section to the west of the Mississippi River Delta rather than the large expanses of open water to the east of the delta in the southern parts of the Breton National Wildlife Refuge (NWR). This document provides information about the potential available sand resources and effects of berm construction on the existing barrier islands. The proposed project originally involved removing sediment from a linear source approximately 1 mile (1.6 km) gulfward of the barrier islands and placing it just seaward of the islands in shallow water (~2-m depth where possible) to form a continuous berm rising approximately 6 feet (~2 m) above sea level (North American Vertical Datum of 1988-NAVD88) with an ~110-yd (~100-m) width at water level and a slope of 25:1 to the seafloor. Discussions within the U.S. Geological Survey (USGS) and with others led to the determination that point-source locations, such as Hewes Point, the St. Bernard Shoals, and Ship Shoal, were more suitable 'borrow

  3. CONGENITAL CATARACT – LACK OF AWARENESS: EFFECTS ON DELAYED HOSPITALIZATION & TREAMENT

    Directory of Open Access Journals (Sweden)

    Anjaneyulu

    2015-01-01

    Full Text Available Study on congenital cataract conducted at regional eye hospital and in coordination with paediatric department. Histry, symptomatology and observations taken inconsideration within days , weeks , months after year. Daignosed by Torch Light examination and s lit lamp examination and B - SCAN examination. Very low number of cases detected out of large number of children screened . It may be due lack of awareness of parents to bring the children to the hospital and health personel. After diagnosing surgical interve ntion done. Post - operative visual prognosis good in some cases and some are amblyopic

  4. It's in the sand

    OpenAIRE

    Mitchell, Clive

    2016-01-01

    Sand is sand isn’t it? Sand gets everywhere but rather than a nuisance it is a valuable, high-purity raw material. Clive Mitchell, Industrial Minerals Specialist at the British Geological Survey (BGS), talks us through what sand is, what it can be used for and how to find it. His exploration of sand takes us from the deserts of Arabia to the damp sand pits of Mansfield!

  5. Quantifying the effects of European beach grass on aeolian sand transport over the last century: Bodega Marine Reserve, California

    Science.gov (United States)

    Cesmat, R.; Werner, S.; Smith, M. E.; Riedel, T.; Best, R.; Olyarnik, S.

    2012-12-01

    fence posts, roots). Conversely, vegetated areas appear prone to sediment accumulation, particularly downwind of unvegetated areas. We measured sand transport using 0.5 m high traps deployed at 18 sites throughout the dune field, and used a linear mixed effects model to predict transport rate as a function of wind and ground cover class, taking into account random effects of sampling date and repeated measurements at each site. The analysis indicates up to 450-times higher transport rates in unvegetated areas relative to vegetated areas at peak wind conditions. We then used these results to parameterize a simple raster-based sediment flux model for the 0.5 km wide study area, using LIDAR-based topography and aerial orthophotography to classify ground cover. Due to the nearly complete compartmentalization of sediment flux by vegetative baffling, the model suggests that proposed restoration (removal of vegetative cover) of the seaward 1 km of the dune system would lead to significant increases in sediment transport in the treated area accompanied by accumulation along its vegetated downwind edge, but little to no change in sand flux within Ammophila-covered areas >0.2 km downwind of restored areas.

  6. Effect of filtration rate on coal-sand dual-media filter performances for microalgae removal.

    Science.gov (United States)

    Sabiri, Nour-Eddine; Monnier, Elodie; Raimbault, Virginie; Massé, Anthony; Séchet, Véronique; Jaouen, Pascal

    2017-02-01

    This study tested the efficiency of granular filtration using a bilayer sand filter for microalgae removal from culture dilutions ranging from 10,000 to 17,000 cells/mL. The objective is to evaluate the removal capacity of the filter without chemical coagulation. Two filter media, sand and anthracite, with mean grain sizes of 0.395 and 1.2 mm, respectively, were used in constant-flow-rate experiments (down-flow mode) with suspensions containing Heterocapsa triquetra microalga. The conventional rapid filtration which usually operates at a constant rate of approximately 5 m(3)/m(2) h is compared to high-rate filtration. Two filtration velocities (5 and 10 m/h) were investigated with bed depth of 1100 mm. Average microalgal cell removal rates were 90% at 5 m/h and 68% at 10 m/h. Turbidity removal was more than 71% at 5 m/h but just 57% at 10 m/h. Head losses did not increase significantly, and values measured at process end were 32 mbar at 5 m/h and 78 mbar at 10 m/h. Retention probabilities were calculated from experimental data. A theoretical model was used to evaluate the contributions of the different drivers of microalgae removal. Hypotheses are developed on the understanding of change in the mechanisms of retention as a function of filtration velocity.

  7. Effects of sand addition on turbulent flow over an immobile gravel bed

    Science.gov (United States)

    Wren, D. G.; Langendoen, E. J.; Kuhnle, R. A.

    2011-03-01

    The factors controlling the complex interaction of a coarse streambed with flow and sediment are difficult to measure. However, planning for reservoir flushing or dam removal requires knowledge of these interactions. In both cases, impounded sediments are introduced to channel beds that have had fine sediment particles removed without replacement. The channel bed pore space interacts with the flow and provides storage for particles. In order to address the need for information on such systems, an adjustable-slope, recirculating laboratory flume was used to study the changes in flow and turbulence caused by sand added to an immobile gravel bed. Detailed measurements were made using an acoustic Doppler velocimeter that collected three velocity components at a rate of 200 Hz. Because of the rough nature of the bed, individual velocity profiles varied significantly; therefore, in order to determine general trends, the data were spatially averaged over six 10 × 20 cm planes parallel to the bed with the lowest plane about 2 cm below the maximum gravel elevation. The increasing elevation of sand relative to the gravel layer resulted in decreased bed shear stress, decreased Reynolds stress, increased relative turbulence intensity, and a near-bed shift toward sweep-dominated turbulence.

  8. Effects of oil sands waste water on the wood frog (rana sylvatica)

    Energy Technology Data Exchange (ETDEWEB)

    Hersikorn, B.; Smits, J.E. [Saskatchewan Univ., Regina, SK (Canada)

    2007-07-01

    The sustainability of various reclamation strategies can be determined by the growth and health of indigenous amphibians (Wood Frogs). This paper referred to the large quantities of tailings water that are generated by oil sand extraction activities. It presented the results of a study that was conducted in the spring and summer of 2006 and 2007 on reclaimed formation wetlands comprising tailings water. The objective was to understand the impact of these wetlands on native amphibians. Frogs were exposed to wetlands containing oil sands process affected water (OSPW) and reference water (no OSPW). Six experimental trenches were made at one site in the first year. Each trench had 3 enclosures with 50 tadpoles. In the second year, there were 13 sites, including 6 reference and 7 OSPW affected sites, which were classified as old (more than 8 yrs) or young (less than 7 yrs). Four enclosures, with 50 tadpoles each, were placed in each wetland. The study involved the evaluation of growth rate, survival, time to metamorphosis, thyroid hormone concentrations, liver EROD activity, and tissue retinol concentrations. In addition, stable isotopes were used to track carbon flow from primary production plants, through the food chain, to tadpoles and frogs which represent intermediate and higher trophic levels in reclaimed wetlands.

  9. Global change and response of coastal dune plants to the combined effects of increased sand accretion (burial) and nutrient availability.

    Science.gov (United States)

    Frosini, Silvia; Lardicci, Claudio; Balestri, Elena

    2012-01-01

    Coastal dune plants are subjected to natural multiple stresses and vulnerable to global change. Some changes associated with global change could interact in their effects on vegetation. As vegetation plays a fundamental role in building and stabilizing dune systems, effective coastal habitat management requires a better understanding of the combined effects of such changes on plant populations. A manipulative experiment was conducted along a Mediterranean dune system to examine the individual and combined effects of increased sediment accretion (burial) and nitrogen enrichment associated with predicted global change on the performance of young clones of Sporobolus virginicus, a widespread dune stabilizing species. Increased burial severity resulted in the production of taller but thinner shoots, while nutrient enrichment stimulated rhizome production. Nutrient enrichment increased total plant biomass up to moderate burial levels (50% of plant height), but it had not effect at the highest burial level (100% of plant height). The effects of such factors on total biomass, shoot biomass and branching were influenced by spatial variation in natural factors at the scale of hundreds of metres. These results indicate that the effects of burial and nutrient enrichment on plant performance were not independent. Their combined effects may not be predicted by knowing the individual effects, at least under the study conditions. Under global change scenarios, increased nutrient input could alleviate nutrient stress in S. virginicus, enhancing clonal expansion and productivity, but this benefit could be offset by increased sand accretion levels equal or exceeding 100% of plant height. Depletion of stored reserves for emerging from sand could increase plant vulnerability to other stresses in the long-term. The results emphasize the need to incorporate statistical designs for detecting non-independent effects of multiple changes and adequate spatial replication in future works to

  10. Effect of liming on yield and quality of peppermint and Sachalin mint in fine sand soil of Northern Finland

    Directory of Open Access Journals (Sweden)

    A. AFLATUNI

    2008-12-01

    Full Text Available Soil acidity commonly limits plant production in the fine sand soil of Northern Finland, which often has a low pH (5.5-6.5 and contains low levels of Ca and Mg. The effect of five liming (10% Mg and 19% Ca levels, 0, 4, 8, 12, and 16 tons ha -1 , on the herb and essential oil yield and menthol and menthone content of two mint species (peppermint, Mentha x piperita, a variety of Black Mitcham and Sachalin mint, Mentha arvensis var. sacchalinensis cultivated in fine sand soil in Northern Finland (6440’N and 2505’E was studied during 1998-2000. Liming clearly increased the pH levels and the Ca and Mg content of the soil. The dry matter content, essential oil quantity, and the menthol or menthone content in mints were not affected by liming. In comparison with no liming however, liming at a rate of 4 t ha -1 doubled the herb yield. The highest yield was achieved in Sachalin mint by liming at 4 or 8 t ha -1 in the second and third year (soil pH 6-6.5 (Ca 725-871 mg l -1 and Mg 122- 219 mg l -1 , and in peppermint by liming at 4, 8 or 16 t ha -1 (soil pH 6-6.6 (Ca 725-1272 mg l -1 and Mg 122-245 mg l -1 . Therefore, we conclude that a higher peppermint and Sachalin mint yield is achieved by increasing soil pH to values above 6.0 in the fine sand soil of Northern Finland.;

  11. Effects of outer membrane protein TolC on the transport of Escherichia coli within saturated quartz sands.

    Science.gov (United States)

    Feriancikova, Lucia; Bardy, Sonia L; Wang, Lixia; Li, Jin; Xu, Shangping

    2013-06-04

    The outer membrane protein (OMP) TolC is the cell surface component of several drug efflux pumps that are responsible for bacterial resistance against a variety of antibiotics. In this research, we investigated the effects of OMP TolC on E. coli transport within saturated sands through column experiments using a wild-type E. coli K12 strain (with OMP TolC), as well as the corresponding transposon mutant (tolC::kan) and the markerless deletion mutant (ΔtolC). Our results showed OMP TolC could significantly enhance the transport of E. coli when the ionic strength was 20 mM NaCl or higher. The deposition rate coefficients for the wild-type E. coli strain (with OMP TolC) was usually >50% lower than those of the tolC-negative mutants. The measurements of contact angles using three probe liquids suggested that TolC altered the surface tension components of E. coli cells and lead to lower Hamaker constants for the cell-water-sand system. The interaction energy calculations using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory suggested that the deposition of the E. coli cell primarily occurred at the secondary energy minimum. The depth of the secondary energy minimum increased with ionic strength, and was greater for the TolC-deletion strains under high ionic strength conditions. Overall, the transport behavior of three E. coli strains within saturated sands could be explained by the XDLVO calculations. Results from this research suggested that antibiotic resistant bacteria expressing OMP TolC could spread more widely within sandy aquifers.

  12. The effect of sewage effluent on the physico-chemical and biological characteristics of the Sand River, Limpopo, South Africa

    Science.gov (United States)

    Seanego, K. G.; Moyo, N. A. G.

    Population growth in urban areas is putting pressure on sewage treatment plants. The improper treatment of sewage entering the aquatic ecosystems causes deterioration of the water quality of the receiving water body. The effect of sewage effluent on the Sand River was assessed. Eight sampling sites were selected, site 1 and 2 were upstream of the sewage treatment plant along the urbanised area of Polokwane, whilst sites 3, 4, 5, 6, 7 and 8 were downstream. The physico-chemical parameters and coliform counts in the water samples were determined. The suitability of the water for irrigation was also determined. Hierarchical average linkage cluster analysis produced two clusters, grouping two sites above the sewage treatment works and six sites downstream of the sewage effluent discharge point. Principal component analysis (PCA) identified total nitrogen, total phosphorus, conductivity and salinity as the major factors contributing to the variability of the Sand River water quality. These factors are strongly associated with the downstream sites. Canonial correspondence analysis (CCA) indicated the macroinvertebrates, Chironomidae, Belastomatidae, Chaoborus and Hirudinea being strongly associated with nitrogen, phosphorus, conductivity and temperature. Escherichia coli levels in the Polokwane wastewater treatment works maturation ponds, could potentially lead to contamination of the Polokwane aquifer. The Sodium Adsorption Ratio was between 1.5 and 3.0 and residual sodium carbonate was below 1.24 Meq/l, indicating that the Sand River water is still suitable for irrigation. The total phosphorus concentrations fluctuated across the different site. Total nitrogen concentrations showed a gradual decrease downstream from the point of discharge. This shows that the river still has a good self-purification capacity.

  13. EFFECTS OF QUERCETIN ON MEMBRANE FLUIDITY OF INJURED VASCULAR ENDOTHELIAL CELLS WITH HYPOXIA AND THE LACK OF GLUCOSE

    Institute of Scientific and Technical Information of China (English)

    林蓉; 刘俊田; 甘伟杰

    2003-01-01

    Objective To study the effects of different concentrations of Quercetin on nitric oxide (NO) production and membrane fluidity of the injured human umbilical vein vascular endothelial cell line(ECV-304) with hypoxia and the lack of glucose. Methods The experiments were performed in the culture of ECV-304 injured with hypoxia and the lack of glucose in vitro. The releases of intracellular lactate dehydrogenase(LDH) of ECV-304 was measured with automatic biochemistry analysis. NO level of ECV-304 was monitored with colorimetry. The membrane fluidity of ECV-304 was measured with the fluorescence polarization method. Results After ECV-304 was cultured in hypoxia and the the lack of glucose for 24 hours, the release of LDH and the membrane fluidity were increased significantly; NO level was decreased. Preincubation of ECV-304 with 20, 80,160μmol*L-1 of Quercetin for 24 hours reduced LDH activity, membrane fluidity and increased the level of NO in hypoxia and the lack of glucose induced ECV-304. Conclusion These results demonstrate that Quercetin can produce the protective effect on hypoxia and the lack of glucose induced injury of ECV-304 by increasing release of NO and changing membrane fluidity.

  14. Effect of microbe as fertilizer on the growth of Acacia mangium on the sand sterile in green house

    Directory of Open Access Journals (Sweden)

    SRI PURWANINGSIH

    2004-07-01

    Full Text Available An experiment on the effect of microbe as fertilizer on the growth of Acacia mangium on the sand sterile in greenhouse. The aim of the experiment the effect and potency of the microbe as fertilizer to increase the growth of A. mangium. The experiment was carried out in green house condition in Microbiology division, Research Center for Biology-LIPI with sterile sand medium. The Rhizobium strains used of: 1.Bio 199R, 2. Bio 203R, 3. Bio 205R, 4 Bio 238R, 5. Bio 251R, 6.Bio 7R, and 7. mixed strains (Bio 199R+Bio 203R+Bio 205R+Bio 238R+Bio 251R+Bio 7R The controls were uninoculated with Rhizobium strain and without urea fertilizer (K1, uninoculated and with urea fertilizer equal 100 kg/ha (K2. The research design was Completely Randomized Design with three replications for each treatment. The plants were harvested after 70 days; the parameters of investigation were the dry weight of canopy, roots, nodules root, total plants, number of nodules and “symbiotic capacity”. The results showed that all of experiment plant able to from nodule. Strain number of mixed strains has given the best results on the growth of A. mangium plant.

  15. Toxic effects of oil sand naphthenic acids on the biomass accumulation of 21 potential phytoplankton remediation candidates.

    Science.gov (United States)

    Woodworth, Adam P J; Frank, Richard A; McConkey, Brendan J; Müller, Kirsten M

    2012-12-01

    The oil sands of northern Alberta, Canada contain an estimated 170 billion barrels of crude oil. Extraction processes produce large amounts of liquid tailings known as oil sand process affected water (OSPW) that are toxic to aquatic organisms. Naphthenic acids (NAs), and their sodium salts, represent a significant contributor to the toxicity of these waters. Due to the recalcitrant nature of these compounds, an effective mode of remediation has yet to be established. This study investigates the suitability of the use of phytoplankton for remediation efforts based on two criteria: the ability of phytoplankton strains to withstand the toxic effects of NAs, and their rate of biomass accumulation. A total of 21 phytoplankton strains were isolated from waters containing NAs, cultured, and maintained under unialgal conditions. These strains were then exposed to NAs in concentrations ranging from 0mg L(-1) to 1000mg L(-1) over a 14 day period. Inhibition of growth was observed at 30mg L(-1) NA (one strain), 100mg L(-1) NA (one strain), 300mg L(-1) NA (six strains), and 1000mg L(-1) NA (six strains). Five strains failed to show any growth inhibition at any test concentration and two strains could not be analysed due to poor growth during the test period. Strains were then ranked based on their suitability for use in remediation efforts.

  16. Porometric properties of siliciclastic marine sand: A comparison of traditional laboratory measurements with image analysis and effective medium modeling

    Science.gov (United States)

    Reed, A.H.; Briggs, K.B.; Lavoie, D.L.

    2002-01-01

    During the 1999 sediment acoustics experiment (SAX99), porometric properties were measured and predicted for a well sorted, medium sand using standard laboratory geotechnical methods and image analysis of resin-impregnated sediments. Sediment porosity measured by laboratory water-weight-loss methods (0.372 ?? 0.0073 for mean ??1 standard deviation) is 0.026 lower than determined by microscopic image analysis of resin-impregnated sediments (0.398 ?? 0.029). Values of intrinsic permeability (m2) determined from constant-head permeameter measurements (3.29 ?? 10-11 ?? 0.60 ?? 10-11) and by microscopic image analysis coupled with effective medium theory modeling (2.78 ?? 10-11 ?? 1.01 ?? 10-11) are nearly identical within measurement error. The mean value of tortuosity factor measured from images is 1.49 ?? 0.09, which is in agreement with tortuosity factor determined from electrical resistivity measurements. Slight heterogeneity and anisotropy are apparent in the top three centimeters of sediment as determined by image-based porometric property measurements. However, the overall similarity for both measured and predicted values of porosity and permeability among and within SAX99 sites indicates sediments are primarily homogeneous and isotropic and pore size distributions are fairly uniform. The results indicate that an effective medium theory technique and two-dimensional image analysis accurately predicts bulk permeability in resin-impregnated sands.

  17. Sand harm in taklimakan Desert highway and sand control

    Institute of Scientific and Technical Information of China (English)

    HANZhiwen; WANGTao; SUNQingwei; DONGZhibao; WANGXunming

    2003-01-01

    Reputed as a wonderful achievement of the world’s highway construction history,the Taklimakan Desert highway is nor facing serious sand drift encroachment problems due to its 447-km-long passage of sand sea consisting of crescent dunes,barchan chains,compound transverse dune ridges and complex megadunes.To solve some technical problems in the protection of the highway from sang drift encroachment,desert experts have been conducting the theoretical and applied studies on sand movement laws;causes,severities and time-space differentiation of sand drift damages;and control ways including mechanical,chemical and biological measures.In this paper the authors give an overall summry on the research contents and recent progress in the control of sand drift damages in China and hold that the theoretical researc results and practices in the prevention of sand drift encroachment on the cross-desert highway represnt a breakthrough and has an cpoch-making significance.Since the construction of protective forest along the cross-desert highway requires large amount of ground water,what will be its environmental consequence and whether it can effectively halt sand drift encroachment on the highway forever are the questions to be studied urgently.

  18. Effect of silty sand in formation water on CO{sub 2} corrosion behavior of carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei, E-mail: weiliu@ustb.edu.cn; Dou, Juanjuan; Lu, Songle; Zhang, Peng; Zhao, Qinghe

    2016-03-30

    Graphical abstract: Silty sand (SiO{sub 2}) promoted the rapid heterogeneous nucleation of corrosion product (FeCO{sub 3}) and simultaneously decreased its grains growth. Silty sand mixed with corrosion product to form the outer layer of corrosion scale with high compactness, blocking the transport of ferrous ions and leading to the formation of the inner layer of corrosion scale without silty sand. The corrosion rate of carbon steel was obviously reduced due to the existence of silty sand in the outer layer by inhibiting anodic and cathodic currents. - Highlights: • CO{sub 2} corrosion rate of carbon steel was obviously reduced due to the existence of silty sand. • The corrosion scale containing silty sand inhibited anodic and cathodic currents, contributing to low corrosion rate. • A development mechanism of corrosion scale in silty sand containing CO{sub 2} environment was proposed. - Abstract: Corrosion behavior of carbon steel in CO{sub 2} aqueous environment containing silty sand was investigated using corrosion mass loss method, scanning electron microscopy (SEM), energy diffraction spectrum (EDS), and various electrochemical measurements. The results show that the corrosion rate of carbon steel was obviously reduced due to the existence of silty sand. Silty sand promoted the rapid heterogeneous nucleation of corrosion product FeCO{sub 3} and simultaneously decreased its grains growth. Silty sand mixed with corrosion product to form the outer layer of corrosion scale with high compactness, blocking the transport of ferrous ions and leading to the formation of the inner layer of corrosion scale without silty sand. The existence of silty sand in the outer layer of corrosion scale inhibited anodic and cathodic currents.

  19. Ageing effect on swell, shrinkage and flexural strength of sand and waste marble powder stabilized expansive soil

    Directory of Open Access Journals (Sweden)

    Oncu Serife

    2016-01-01

    Full Text Available Expansive soils in semi-arid climates must be mitigated to minimize potential structural damage to the overlying structures due to swell-shrink behavior caused by climatic changes. The expansive soil in this study was amended by sand which reduced the swell-shrink potential significantly. As a secondary additive, a waste by product of construction industry was selected, marble powder. Recycling this material would minimize its accumulation and covering a large space in landfill areas. In this study, waste material was assessed as a possible partial replacement for sand and due to its high calcite content, curing effect on its cementitious characteristic was also evaluated. It was observed that for mitigating the swell-shrink potential, 10% marble powder by dry mass was the optimum amount which was observed to gain improved characteristics with curing. The flexural strength, however, slightly reduced with marble powder addition, the soil mixture displayed a brittle behavior. Therefore the utilization of this material is recommended to be restricted to soils exposed to lower flexural loads, such as light traffic. The correlation between shrinkage strains and flexural strength parameters suggested herein, could be a potential empirical approach to predict the flexural strength based on shrinkage behavior.

  20. Novel iron metal matrix composite reinforced by quartz sand for the effective dechlorination of aqueous 2-chlorophenol.

    Science.gov (United States)

    Zhang, Yunfei; Yang, Bo; Han, Yanni; Jiang, Chaojin; Wu, Deli; Fan, Jinhong; Ma, Luming

    2016-03-01

    In this work, we tested a novel iron metal matrix composite (MMC) synthesized by mechanically introducing quartz sand (SiO2) into an iron matrix (denoted as SiO2-Fe MMC). The pseudo-first-order reaction rate constant of the SiO2-Fe MMC (initial pH 5.0) for 20 mg/L of 2-chlorophenol (2-CP) was 0.051 × 10(-3) L/m(2)/min, which was even higher than that of some reported Pd/Fe bimetals. This extraordinary high activity was promoted by the quick iron dissolution rate, which was caused by the formation of Fe-C internal electrolysis from carbonization of process control agent (PCA) and the active reinforcement/metal interfaces during the milling process. In addition, pH has slight effect on the dechlorination rate. The SiO2-Fe MMC retained relatively stable activity, still achieving 71% removal efficiency for 2-CP after six consecutive cycles. The decrease in dechlorination efficiency can be attributed to the rapid consumption of Fe(0). A dechlorination mechanism using the SiO2-Fe MMC was proposed by a direct electron transfer from Fe(0) to 2-CP at the quartz sand/iron interface.

  1. Effect of filter media thickness on the performance of sand drying beds used for faecal sludge management.

    Science.gov (United States)

    Manga, M; Evans, B E; Camargo-Valero, M A; Horan, N J

    2016-12-01

    The effect of sand filter media thickness on the performance of faecal sludge (FS) drying beds was determined in terms of: dewatering time, contaminant load removal efficiency, solids generation rate, nutrient content and helminth eggs viability in the dried sludge. A mixture of ventilated improved pit latrine sludge and septage in the ratio 1:2 was dewatered using three pilot-scale sludge drying beds with sand media thicknesses of 150, 250 and 350 mm. Five dewatering cycles were conducted and monitored for each drying bed. Although the 150 mm filter had the shortest average dewatering time of 3.65 days followed by 250 mm and 350 mm filters with 3.83 and 4.02 days, respectively, there was no significant difference (p > 0.05) attributable to filter media thickness configurations. However, there was a significant difference for the percolate contaminant loads in the removal and recovery efficiency of suspended solids, total solids, total volatile solids, nitrogen species, total phosphorus, chemical oxygen demand, dissolved chemical oxygen demand and biochemical oxygen demand, with the highest removal efficiency for each parameter achieved by the 350 mm filter. There were also significant differences in the nutrient content (NPK) and helminth eggs viability of the solids generated by the tested filters. Filtering media configurations similar to 350 mm have the greatest potential for optimising nutrient recovery from FS.

  2. A cognitive rehabilitation paradigm effective in male rats lacks efficacy in female rats.

    Science.gov (United States)

    Langdon, Kristopher D; Granter-Button, Shirley; Harley, Carolyn W; Moody-Corbett, Frances; Peeling, James; Corbett, Dale

    2014-10-01

    Cognitive dysfunction, as a consequence of dementia, is a significant cause of morbidity lacking efficacious treatment. Females comprise at least half of this demographic but have been vastly underrepresented in preclinical studies. The current study addressed this gap by assessing the protective efficacy of physical exercise and cognitive activity on learning and memory outcomes in a rat model of vascular dementia. Forty ovariectomized Sprague-Dawley rats (∼6 months old) were exposed to either a diet high in saturated fats and refined sugars or standard laboratory chow and underwent either chronic bilateral carotid occlusion or Sham surgery. Learning and memory abilities were evaluated using standard cognitive outcomes over the ensuing 6 months, followed by histologic analyses of hippocampal CA1 neurons. In Experiment 1, we confirmed hypoperfusion-induced cognitive dysfunction using a 2 × 2 (Surgery × Diet) experimental design, without alterations in hippocampal architecture. In Experiment 2, hypoperfused animals were either exposed to alternating days of physical (wheel running) and cognitive activity (modified Hebb-Williams maze) or sedentary housing. In contrast to males, this combination rehabilitation paradigm did not improve cognition or histopathologic outcomes in hypoperfused animals. These findings, highlighting differences between female and male animals, show the necessity of including both sexes in preclinical experimentation.

  3. Lack of effective anti-apoptotic activities restricts growth of Parachlamydiaceae in insect cells.

    Directory of Open Access Journals (Sweden)

    Barbara S Sixt

    Full Text Available The fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens Chlamydia trachomatis and Chlamydia (Chlamydophila pneumoniae. As inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might represent emerging pathogens. While Simkania negevensis was able to efficiently replicate within insect cells, which served as model for metazoan-derived host cells, the Parachlamydiaceae (Parachlamydia acanthamoebae and Protochlamydia amoebophila displayed limited intracellular growth, yet these bacteria induced typical features of apoptotic cell death, including formation of apoptotic bodies, nuclear condensation, internucleosomal DNA fragmentation, and effector caspase activity. Induction of apoptosis was dependent on bacterial activity, but not bacterial de novo protein synthesis, and was detectable already at very early stages of infection. Experimental inhibition of host cell death greatly enhanced parachlamydial replication, suggesting that lack of potent anti-apoptotic activities in Parachlamydiaceae may represent an important factor compromising their ability to successfully infect non-protozoan hosts. These findings highlight the importance of the evolution of anti-apoptotic traits for the success of chlamydiae as pathogens of humans and animals.

  4. Industrial sand and gravel

    Science.gov (United States)

    Dolley, T.P.

    2013-01-01

    Domestic production of industrial sand and gravel in 2012 was about 49.5 Mt (55 million st), increasing 13 percent compared with that of 2011. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

  5. LACK OF EFFECT OF CETIRIZINE ON EARLY AND LATE ASTHMATIC RESPONSE AFTER ALLERGEN CHALLENGE

    NARCIS (Netherlands)

    DEBRUINWELLER, MS; RIJSSENBEEKNOUWENS, LHM; DEMONCHY, JGR

    Background: Cetirizine hydrochloride has proved effective in reducing allergic symptoms and can inhibit the infiltration of eosinophils in allergic late-phase responses in the skin. Because eosinophils are likely to play an important role in allergic late-phase reactions, we studied the effect of

  6. Lack of clastogenic effects in cultured human lymphocytes treated with hydroquinone

    NARCIS (Netherlands)

    Roza, L.; Vogel, N. de; Delft, J.H.M. van

    2003-01-01

    Hydroquinone (HQ) occurs in the environment as a result of manmade processes as well as in natural products from plants and animals. The compound has been reported to produce chromosomal effects in some in vivo and in vitro animal models. However, its potential to produce similar effects in human ly

  7. LACK OF EFFECT OF CETIRIZINE ON EARLY AND LATE ASTHMATIC RESPONSE AFTER ALLERGEN CHALLENGE

    NARCIS (Netherlands)

    DEBRUINWELLER, MS; RIJSSENBEEKNOUWENS, LHM; DEMONCHY, JGR

    1994-01-01

    Background: Cetirizine hydrochloride has proved effective in reducing allergic symptoms and can inhibit the infiltration of eosinophils in allergic late-phase responses in the skin. Because eosinophils are likely to play an important role in allergic late-phase reactions, we studied the effect of ce

  8. Lack of clastogenic effects in cultured human lymphocytes treated with hydroquinone

    NARCIS (Netherlands)

    Roza, L.; Vogel, N. de; Delft, J.H.M. van

    2003-01-01

    Hydroquinone (HQ) occurs in the environment as a result of manmade processes as well as in natural products from plants and animals. The compound has been reported to produce chromosomal effects in some in vivo and in vitro animal models. However, its potential to produce similar effects in human ly

  9. The lack of behavioral effects of fenbendazole: a medication for pinworm infection.

    Science.gov (United States)

    Keen, Richard; Macinnis, Mika; Guilhardi, Paulo; Chamberland, Karen; Church, Russell

    2005-03-01

    Pinworm infection in rodent laboratories is common and often treated with fenbendazole, which is effective and has a low toxicity level. However, very little is known about the behavioral effects of the drug. The purpose of this study was to determine the behavioral effects of fenbendazole on rats tested by using various conditioning and timing procedures. These behavioral effects were examined both between animals (i.e., control versus medicated treatments) and within animals (baseline-treatment-baseline design). Fenbendazole reduced the detection of pinworm eggs, and it had no significant behavioral effects across multiple levels of analysis (e.g., from overall response rates to response patterns to interresponse intervals). All behavioral differences (e.g., discrimination ratios) were a result of task variables. These results suggest that behavioral studies are unlikely to be influenced by fenbendazole treatment given before or during a study.

  10. Likely effects of construction of Scroby Sands offshore wind farm on a mixed population of harbour Phoca vitulina and grey Halichoerus grypus seals.

    Science.gov (United States)

    Skeate, Eleanor R; Perrow, Martin R; Gilroy, James J

    2012-04-01

    Scroby Sands offshore wind farm was built close to a haul-out and breeding site for harbour seal, a species of conservation concern. An aerial survey programme conducted during a five-year period spanning wind farm construction, revealed a significant post-construction decline in haul-out counts. Multivariate model selection suggested that the decline was not related to the environmental factors considered, nor did it mirror wider population trends. Although cause and effect could not be unequivocally established, the theoretical basis of hearing in pinnipeds and previous studies suggested that extreme noise (to 257 dB re 1 μ Pa(pp) @ 1m) generated by pile-driving of turbine bases led to displacement of seals. A lack of full recovery of harbour seal during the study was also linked to their sensitivity to vessel activity and/or rapid colonisation of competing grey seal. Any impact of offshore wind farm development upon pinnipeds would be much reduced without pile-driving.

  11. -Amphetamine and Antipsychotic Drug Effects on Latent Inhibition in Mice Lacking Dopamine D2 Receptors

    OpenAIRE

    Bay-Richter, C.; O'Callaghan, M J; N Mathur; O'Tuathaigh, C.M.P.; Heery, D M; Fone, K C F; Waddington, J. L.; Moran, P.M.

    2013-01-01

    Drugs that induce psychosis, such as -amphetamine (AMP), and those that alleviate it, such as antipsychotics, are suggested to exert behavioral effects via dopamine receptor D2 (D2). All antipsychotic drugs are D2 antagonists, but D2 antagonism underlies the severe and debilitating side effects of these drugs; it is therefore important to know whether D2 is necessary for their behavioral effects. Using D2-null mice (Drd 2 −/−), we first investigated whether D2 is required for AMP disruption ...

  12. The effects of herbivory by a mega- and mesoherbivore on tree recruitment in sand forest, South Africa.

    Directory of Open Access Journals (Sweden)

    D D Georgette Lagendijk

    Full Text Available Herbivory by megaherbivores on woody vegetation in general is well documented; however studies focusing on the individual browsing effects of both mega- and mesoherbivore species on recruitment are scarce. We determined these effects for elephant Loxodonta africana and nyala Tragelaphus angasii in the critically endangered Sand Forest, which is restricted to east southern Africa, and is conserved mainly in small reserves with high herbivore densities. Replicated experimental treatments (400 m(2 in a single forest patch were used to exclude elephant, or both elephant and nyala. In each treatment, all woody individuals were identified to species and number of stems, diameter and height were recorded. Results of changes after two years are presented. Individual tree and stem densities had increased in absence of nyala and elephant. Seedling recruitment (based on height and diameter was inhibited by nyala, and by elephant and nyala in combination, thereby preventing recruitment into the sapling stage. Neither nyala or elephant significantly reduced sapling densities. Excluding both elephant and nyala in combination enhanced recruitment of woody species, as seedling densities increased, indicating that forest regeneration is impacted by both mega- and mesoherbivores. The Sand Forest tree community approached an inverse J-shaped curve, with the highest abundance in the smaller size classes. However, the larger characteristic tree species in particular, such as Newtonia hildebrandtii, were missing cohorts in the middle size classes. When setting management goals to conserve habitats of key importance, conservation management plans need to consider the total herbivore assemblage present and the resulting browsing effects on vegetation. Especially in Africa, where the broadest suite of megaherbivores still persists, and which is currently dealing with the 'elephant problem', the individual effects of different herbivore species on recruitment and

  13. Lack of modulatory effect of asparagus, tomato, and grape juice on ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... hormones, immune systems and other metabolic pathways (DiMasico et .... modulatory effect of the plant juices on CP-induced frequency of. MNPCE and toxicity, the ..... Laboratory Press, Cold Spring Harbor, NY), pp. 23-45.

  14. Lack of effect of zinc sulfate on wheezing after bronchiolitis in infants less than two years

    OpenAIRE

    R Abasi; S H Asadi; K.Keshavarz; M Zoladl; S Kazeroono; C sharafieyan; Z Mohammadhosiemi

    2014-01-01

    Backgrounds & aim: Wheezing after bronchiolitis is known as a risk factor for asthma. No cure or effective vaccine has been identified for such disease. The purpose of this study was to determine the effects of zinc sulfate on persistent wheezing after bronchiolitis in infants less than two years. Methods: The present randomized clinical trial study was conducted on 90 infants under two years of age suffering from the first attack with a clinical diagnosis of bronchiolitis wheezing hosp...

  15. Sand Failure Mechanism and Sanding Parameters in Niger Delta Oil Reservoirs

    OpenAIRE

    Sunday Isehunwa,; Andrew Farotade

    2010-01-01

    Sand production is a major issue during oil and gas production from unconsolidated reservoirs. In predicting the onset of sand production, it is important to accurately determine the failure mechanism and the contributing parameters. The aim of this study was to determine sand failure mechanism in the Niger-Delta, identify themajor contributing parameters and evaluate their effects on sanding.Completion and production data from 78 strings completed on 22 reservoirs in a Niger Delta oil Field ...

  16. Low calorie sweeteners: Evidence remains lacking for effects on human gut function.

    Science.gov (United States)

    Bryant, Charlotte; Mclaughlin, John

    2016-10-01

    The importance of nutrient induced gut-brain signalling in the regulation of human food intake has become an increasing focus of research. Much of the caloric excess consumed comes from dietary sugars, but our knowledge about the mechanisms mediating the physiological and appetitive effects of sweet tastants in the human gut and gut-brain axis is far from complete. The comparative effects of natural sugars vs low calorie sweeteners are also poorly understood. Research in animal and cellular models has suggested a key functional role in gut endocrine cells for the sweet taste receptors previously well described in oral taste. However human studies to date have very consistently failed to show that activation of the sweet taste receptor by low calorie sweeteners placed in the human gut fails to replicate any of the effects on gastric motility, gut hormones or appetitive responses evoked by caloric sugars. Copyright © 2016. Published by Elsevier Inc.

  17. Lack of an aging effect on responses to disopyramide in rabbit ventricle. A brief note.

    Science.gov (United States)

    Mokler, C M

    1982-02-01

    The hearts of older animals, including man, undergo physiological changes and exhibit an increased sensitivity to antiarrhythmic drugs which may be due in part to an increased sensitivity of the heart to the drug. Isolated perfused hearts from young (2-4 months) and old (43-63 months) rabbits were driven at 3 Hz and the electrical strength-interval relationship was determined by interposing a test stimulus at known intervals after every tenth driving stimulus. This revealed the diastolic threshold for stimulation and the effective refractory period. Disopyramide at therapeutic concentrations increased the effective refractory period in both young and old hearts to the same extent without significantly altering the diastolic threshold. Thus, the increased sensitivity of older animals to type I antiarrhythmic drugs is probably due to some factor other than increased cardiac electrophysiologic effects.

  18. Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints.

    Energy Technology Data Exchange (ETDEWEB)

    Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

    2008-05-07

    The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, {gamma}-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of {gamma}-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

  19. Lack of effect of a 24-hour infusion of iloprost in intermittent claudication.

    Science.gov (United States)

    Hay, C R; Waller, P C; Carter, C; Cameron, H A; Parnell, L; Ramsay, L E; Preston, F E; Greaves, M

    1987-04-15

    24 hour infusion of iloprost was compared with placebo infusion in 19 patients with stable intermittent claudication using a double blind, balanced crossover design. Despite significant inhibition of platelet aggregation to ADP and collagen (p less than 0.001) and the typical cardiovascular and gastrointestinal side effects, there was no significant effect on treadmill exercise times at any time up to 6 weeks after infusion. The 95% confidence limits indicated that an improvement of more than 25% was unlikely to occur. No significant changes in B thromboglobulin, platelet aggregate ratio, bleeding time, whole blood viscosity and euglobulin clot lysis time were demonstrated.

  20. Geodesic completeness and the lack of strong singularities in effective loop quantum Kantowski-Sachs spacetime

    Science.gov (United States)

    Saini, Sahil; Singh, Parampreet

    2016-12-01

    Resolution of singularities in the Kantowski-Sachs model due to non-perturbative quantum gravity effects is investigated. Using the effective spacetime description for the improved dynamics version of loop quantum Kantowski-Sachs spacetimes, we show that even though expansion and shear scalars are universally bounded, there can exist events where curvature invariants can diverge. However, such events can occur only for very exotic equations of state when pressure or derivatives of energy density with respect to triads become infinite at a finite energy density. In all other cases curvature invariants are proved to remain finite for any evolution in finite proper time. We find the novel result that all strong singularities are resolved for arbitrary matter. Weak singularities pertaining to above potential curvature divergence events can exist. The effective spacetime is found to be geodesically complete for particle and null geodesics in finite time evolution. Our results add to a growing evidence for generic resolution of strong singularities using effective dynamics in loop quantum cosmology by generalizing earlier results on isotropic and Bianchi-I spacetimes.

  1. Lack of Effect of Lactose Digestion Status on Baseline Fecal Microflora

    Directory of Open Access Journals (Sweden)

    Andrew Szilagyi

    2009-01-01

    Full Text Available BACKGROUND: The genetics of intestinal lactase divide the world’s population into two phenotypes: the ability (a dominant trait or inability (a recessive trait to digest lactose. A prebiotic effect of lactose may impact the colonic flora of these phenotypes differently.

  2. Lack of correlation between MYCN expression and the Warburg effect in neuroblastoma cell lines

    Directory of Open Access Journals (Sweden)

    Hatzinisiriou Irene

    2008-09-01

    Full Text Available Abstract Background Many cancers preferentially meet their energy requirements through the glycolytic pathway rather than via the more efficient oxidative phosphorylation pathway. It is thought that this is an important adaptation in cancer malignancy. We investigated whether use of glycolysis for energy production even in the presence of oxygen (known as the Warburg effect varied between neuroblastoma cell lines with or without MYCN amplification (a key indicator of poor disease outcome in neuroblastoma. Methods We examined ATP and lactate production, oxygen consumption and mitochondrial energisation status for three neuroblastoma cell lines with varying degrees of MYCN amplification and MYCN expression. Results We found no correlation between MYCN expression and the Warburg effect in the cell lines investigated. Conclusion Our results suggest preferential use of glycolysis for energy production and MYCN expression may be independent markers of neuroblastoma malignancy in vitro if not in vivo.

  3. Lack of effects of astemizole on vestibular ocular reflex, motion sickness, and cognitive performance in man

    Science.gov (United States)

    Kohl, Randall L.; Homick, Jerry L.; Cintron, Nitza; Calkins, Dick S.

    1987-01-01

    Astemizole was orally administered to 20 subjects in a randomized, double-blind design to assess the efficacy of this peripherally active antihistamine as an antimotion sickness drug possessing no central side-effects. Measures of vestibular ocular reflex (VOR) were made to evaluate the agent as a selective vestibular depressant. Following one week of orally administered astemizole (30 mg daily), a Staircase Profile Test, a VOR test, and a variety of tests of cognitive performance were administered. These tests revealed no statistically significant effects of astemizole. This leads to the conclusion that, although the drug probably reaches the peripheral vestibular apparatus in man by crossing the blood-vestibular barrier, a selective peripheral antihistamine (H1) action is inadequate to control motion sickness induced through cross-coupled accelerative semicircular canal stimulation in a rotating chair.

  4. The Immunomodulation Effect of Aronia Extract Lacks Association with Its Antioxidant Anthocyanins

    DEFF Research Database (Denmark)

    Mojsoska, Biljana; Xu, Jin

    2013-01-01

    was developed to obtain high-purity anthocyanins in the extract. The antioxidative activity of the extract, the anthocyanin-rich fraction (AF) was determined by 1,1-diphenyl-2-picrylhydrazyl radical and ferric-reducing ability of plasma along with resveratrol as a reference. The immunomodulation properties were...... assessed in lipopolysaccharide (LPS)-stimulated human monocytes mono mac 6. The isolated AF, containing six different anthocyanins, exhibited a stronger antioxidative capacity compared to resveratrol. Resveratrol enhanced tumor necrosis factor-alpha and reduced interleukin-10 (IL-10) production by LPS......, whereas AF only had a slight effect in reducing IL-10. These results demonstrated that there was no major relationship between the antioxidative effect and immunomodulation capacities of AF and resveratrol. The immunomodulatory activity of the extract is associated with bioactive compounds in Aronia other...

  5. Lack of a Negative Effect of BCG-Vaccination on Child Psychomotor Development

    DEFF Research Database (Denmark)

    Kjærgaard, Jesper; Stensballe, Lone Graff; Birk, Nina Marie

    2016-01-01

    MEASURES: Psychomotor development measured using Ages and Stages Questionnaire (ASQ) completed by the parents at 12 months. Additionally, parents of premature children (gestational age Developmental assessment was available for 3453/4262 (81%). RESULTS......OBJECTIVES: To assess the non-specific effect of Bacillus Calmette-Guérin (BCG) vaccination at birth on psychomotor development. DESIGN: This is a pre-specified secondary outcome from a randomised, clinical trial. SETTING: Maternity units and paediatric wards at three university hospitals...... was -7.8 points (-20.6 to 5.0, p = 0.23), d = -0.23 (-0.62 to 0.15). CONCLUSIONS: A negative non-specific effect of BCG vaccination at birth on psychomotor development was excluded in term children. TRIAL REGISTRATION: ClinicalTrials.gov NCT01694108....

  6. The lack of endocrine disrupting effects in catfish (Clarias gariepinus) from a DDT sprayed area.

    Science.gov (United States)

    Brink, Kerry; van Vuren, Johan Jansen; Bornman, Riana

    2012-05-01

    The exposure and response of the catfish, Clarias gariepinus, was studied in male specimens collected in the vicinity of a DDT spraying programme to control malaria. Two sites were situated in the DDT sprayed areas and one site upstream from exposed areas, used as a reference site. The collected specimens were analysed for DDT bioaccumulation and the extent of associated effects. The concentration of all DDT metabolites including p,p'-and o,p'-forms of DDT, DDE and DDD, were measured in the adipose tissue, whilst the effects were measured using a range of biomarkers. This included assessing the effectiveness of plasma calcium, magnesium, zinc and alkali-labile phosphates (ALPs) as indirect measures of vitellogenin (VTG). Gonad condition was determined by calculating the gonadosomatic index (GSI) for each individual and comparing it with the gonad mass that were adjusted with Analysis of Covariance (ANCOVA). The presence of intersex in gonads was identified and the overall body condition determined using the condition factor (CF). Overall, none of the biomarkers showed significant change in the presence of high levels of DDT nor lindane, dieldrin and endosulfan II. Subtle responses in the plasma concentrations of calcium, ALP and gonad condition were evident in the catfish where DDT concentrations were highest, whilst no effects related to intersex and body condition were evident. Overall this study highlighted the tolerance of C. gariepinus to DDT contamination, the practical implications of using biomarkers in developing countries, and the need for further research into developing biomarkers for much needed biomonitoring programmes in areas where malarial control programmes continue to use DDT.

  7. Spirulina platensis Lacks Antitumor Effect against Solid Ehrlich Carcinoma in Female Mice

    OpenAIRE

    Waleed Barakat; Elshazly, Shimaa M.; Amr A A Mahmoud

    2015-01-01

    Spirulina is a blue-green alga used as a dietary supplement. It has been shown to possess anti-inflammatory, antioxidant, and hepatoprotective properties. This study was designed to evaluate the antitumor effect of spirulina (200 and 800 mg/kg) against a murine model of solid Ehrlich carcinoma compared to a standard chemotherapeutic drug, 5-fluorouracil (20 mg/kg). Untreated mice developed a palpable solid tumor after 13 days. Unlike fluorouracil, spirulina at the investigated two dose levels...

  8. Anticipatory anxiety in children visiting the dentist: lack of effect of preparatory information.

    Science.gov (United States)

    Olumide, Funmi; Newton, J Tim; Dunne, Stephen; Gilbert, David B

    2009-09-01

    This study sought to explore whether viewing a leaflet explaining the benefits of dental treatment would have a significant impact on children's anticipatory anxiety. Fifty children aged 8-12, attending the paediatric dental clinic of King's College Hospital, London, took part in this triple-masked, randomized control study. The participants were randomly allocated to one of two groups and either shown an intervention leaflet containing child-friendly dental information (the experimental group) or a leaflet with child-friendly information on the benefits of healthy eating (the control group). Using the Facial Image Scale, anxiety was measured when the children arrived for their dental appointment, once before reading the leaflet and again after reading the leaflet. There was no statistically significant effect of the experimental leaflet on self-reported anxiety levels in this study, although anxiety levels did drop slightly in both groups after reading a leaflet. Providing paediatric patients with preparatory information about what to expect from a visit to the dentist had no effect on anticipatory anxiety in comparison to reading a leaflet about healthy eating. We speculate that reading, or cognitive processing, may have some beneficial effect. Future work should investigate this possibility.

  9. Demonstrating a lack of brand/cause effects on point of sale donations

    Directory of Open Access Journals (Sweden)

    Coleman Joshua T.

    2015-10-01

    Full Text Available Point of sale cause-related marketing has raised over $2 billion for charities over the past 30 years, yet the subject remains largely unexplored in academic literature. The subject of brand/cause fit, however, is prolific throughout extant research, with many studies showing that high congruence between a company and a charity is necessary to achieve philanthropic success. This paper challenges current marketing thinking both conceptually and empirically. Employing tests of no-effect hypotheses following the guidelines set out by Cortina and Folger (1998, it is established that, in the point of sale cause-related marketing context, the traditional effects of brand/cause fits do not apply. Across three studies involving experimental designs and over 500 respondents, the results of one-way ANOVA analyses consistently demonstrate that a low brand/cause fit can be just as effective as a high/brand cause fit. These findings contribute to a profound understanding of social efforts such as cause-related marketing may not be as simple or easily understood as was once thought.

  10. Lack of effect of zinc sulfate on wheezing after bronchiolitis in infants less than two years

    Directory of Open Access Journals (Sweden)

    R Abasi

    2014-10-01

    Full Text Available Backgrounds & aim: Wheezing after bronchiolitis is known as a risk factor for asthma. No cure or effective vaccine has been identified for such disease. The purpose of this study was to determine the effects of zinc sulfate on persistent wheezing after bronchiolitis in infants less than two years. Methods: The present randomized clinical trial study was conducted on 90 infants under two years of age suffering from the first attack with a clinical diagnosis of bronchiolitis wheezing hospitalized in Imam Sajjad Hospital, Yasuj. All infants were equally placed in test groups and control group. In addition to bronchiolitis usual treatment, test group received 20 mg of elemental zinc for seven days. Patient information including risk factors associated with wheezing and persistent wheezing were compared 48 hours and two weeks after treatment. Data were analyzed using chi-square and t tests. Results: In all 90 infants diagnosed with bronchiolitis, wheezing was observed. After 48 hours and two weeks wheezing was continued in 67 patients (74.4% and 54 patients (60% respectively Conclusion: The results showed Zinc sulfate had no effect on the improvement of wheezing after bronchiolitis.

  11. In vitro evaluation of the toxic effects and endocrine disrupting potential of oil sands processed water and naphthenic acids

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Wiseman, S.; Higley, E.; Jones, P.D.; Hecker, M.; Giesy, J.P. [Saskatchewan Univ., Saskatoon, SK (Canada); Gamel El Din, M.; Martin, J.W. [Alberta Univ., Edmonton, AB (Canada)

    2009-07-01

    Naphthenic acids (NAs) are the primary toxic constituents of oil sands process-affected waters (OSPW). This presentation reported on a series of in vitro studies that were initiated to evaluate potential endocrine modulating effects of OSPW and their constituent NAs. The H295R steroidogenesis bioassay was used to examine the impact of OSPW and NA on 52 steroidogenesis. In particular, dose-response and time course studies were conducted to evaluate the impact of OSPW and NAs on testosterone and estradiol production. Aromatase activity and transcript abundance of the key 11 steroidogenic enzymes were also quantified to complement analysis of hormone levels. The MVLN trans-activation assay was used to test the estrogenicity/anti-estrogenicity of OSPW and NAs. In vitro cell viability and apoptosis (live-dead) caused by OSPW and NAs was quantified by the MTS reduction and caspase-3/7 activity in H295R and MVLN cells.

  12. Lack of combined effects of exposure and smoking on respiratory health in aluminium potroom workers.

    Science.gov (United States)

    Radon, K; Nowak, D; Szadkowski, D

    1999-07-01

    To investigate the combined influence on respiratory health of smoking and exposure in an aluminium potroom. In a cross sectional study of 75 potroom workers (23 never smokers, 38 current smokers, 14 ex-smokers) and 56 controls in the same plant (watchmen, craftsmen, office workers, laboratory employees; 18 non-smokers, 21 current smokers, 17 ex-smokers), prevalences of respiratory symptoms and spirometric indices were compared. Smokers in the potroom group had a lower prevalence of respiratory symptoms than never smokers or ex-smokers, which was significant for wheezing (2.6% v 17.4% and 28.6% respectively, both p < 0.01), whereas respiratory symptoms in controls tended to be highest in smokers (NS). No effects of potroom work on the prevalence of respiratory symptoms could be detected. In potroom workers, impairment of lung function due to occupational exposure was found only in non-smokers, with lower results for forced vital capacity (FVC) (98.8% predicted), forced expiratory volume in one second (FEV1) (96.1% predicted) and peak expiratory flow (PEF) (80.2% predicted) compared with controls (114.2, 109.9, and 105.9% predicted; each p < 0.001). Conversely, effects of smoking on lung function were only detectable in non-exposed controls (current smokers v non-smokers: FVC 98.8% v 114.2% predicted; p < 0.01; FEV1 95.5 v 109.9% predicted; p < 0.05). In a cross sectional survey such as this, the effects of both smoking and occupational exposure on respiratory health may be masked in subjects with both risk factors. This is probably due to strong selection processes which result in least susceptible subjects continuing to smoke and working in an atmosphere with respiratory irritants.

  13. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...

  14. Lack of effect of propranolol in the treatment of lymphangioma in two children.

    Science.gov (United States)

    Maruani, Annabel; Brown, Shanna; Lorette, Gerard; Pondaven-Letourmy, Soizick; Herbreteau, Denis; Eisenbaum, Allan

    2013-01-01

    Vascular lesions such as hemangiomas and lymphangiomas can cause significant mortality and morbidity, as well as amblyopia when located in the orbit. Oral propranolol can regress infantile hemangioma during infancy and up to 23 months of age, but its effect on lymphangioma has not been demonstrated. We present two cases of lymphatic malformations treated with oral propranolol. Patient 1 is a 2-year-old boy with macrocystic bilateral cervical lymphangioma extending to the pharynx and larynx and microcystic lymphangioma of the tongue. The patient was started on propranolol 2 mg/kg/day starting at 17 months of age, and after 3 months only a very slight decrease in tongue volume was noted. Patient 2 is a 3.5-year-old boy with magnetic resonance imaging evidence of right facial complex lymphangioma with venous malformation. The patient was placed on oral propranolol 2 mg/kg/day. After 3 months of treatment, no change in the lesion was noted except for a transient decrease in the size of the conjunctival telangiectasia. Propranolol 2 mg/kg/day was not effective in treating lymphatic malformations in two children, both older than 17 months at the time of treatment. © 2012 Wiley Periodicals, Inc.

  15. The ISW effect and the lack of large-angle CMB temperature correlations

    CERN Document Server

    Copi, Craig J; Starkman, Glenn D

    2016-01-01

    It is by now well established that the magnitude of the two-point angular-correlation function of the cosmic microwave background temperature anisotropies is anomalously low for angular separations greater than about 60 degrees. Physics explanations of this anomaly typically focus on the properties of the Universe at the surface of last scattering, relying on the fact that large-angle temperature fluctuations are dominated by the Sachs-Wolfe effect (SW). However, these fluctuations also receive important contributions from the integrated Sachs-Wolfe effect (ISW) at both early (eISW) and late ($\\ell$ISW) times. Here we study the correlations in those large-angle temperature fluctuations and their relative contributions to $S_{1/2}$ -- the standard measure of the correlations on large angular scales. We find that in the best-fitting $\\Lambda$CDM cosmology, while the auto-correlation of the early contributions (SW plus eISW) dominates $S_{1/2}$, there are also significant contributions originating from cross-ter...

  16. Lack of Prophylactic Effects of Aloe Vera Gel on Radiation Induced Dermatitis in Breast Cancer Patients

    Science.gov (United States)

    Ahmadloo, Niloofar; Kadkhodaei, Behnam; Omidvari, Shapour; Mosalaei, Ahmad; Ansari, Mansour; Nasrollahi, Hamid; Hamedi, Sayed Hasan; Mohammadianpanah, Mohammad

    2017-01-01

    Purpose: Radiotherapy induced dermatitis is a common and sometimes serious side effect. We conducted a randomized study to understand whether the adjunctive use of aloe vera gel might reduce the prevalence and/or severity of radiotherapy induced dermatitis. Methods: One hundred patients with newly diagnosed breast cancer were randomized to receive aloe vera gel or nothing during adjuvant radiotherapy consisting of conventional external beam radiation using 6 MV mega voltage linear accelerator photons. The radiation portals were composed of breast fields in all patients and supraclavicular and posterior axillary fields in node positive cases. The total dose was 50 Gy with a daily fraction of 2 Gy, five fractions per week. Results: Dermatitis was first found among patients of both groups after week 2. In the aloe vera and control groups, 2/8 patients and 5/12 patients had dermatitis grade 1 after weeks 2 (P value = 0.240) and 3 (P value = 0.317). After the 4th week, the numbers were 18 and, 23 fordermatitis grade 1 and only 1 for grade 3 dermatitis (P value = 0.328). After the 5th week, 31, 12 and 2 patients in the aloe vera group and 36, 6 and 5 of the controls had grades 1, 2 and 3 dermatitis, respectively (P value = 0.488). Conclusion: Aloe vera exerted no positive effect on prevalence orseverity of radiation dermatitis in this study. PMID:28547955

  17. Lack of effect of methotrexate in budesonide-refractory collagenous colitis

    Directory of Open Access Journals (Sweden)

    Münch A

    2013-08-01

    Full Text Available Andreas Münch,1,* Johan Bohr,2,3,* Lina Vigren,4 Curt Tysk,2,3,* Magnus Ström1,* 1Division of Gastroenterology and Hepatology, Department of Clinical and Experimental Medicine, Faculty of Health Science, Linköping University, Linköping, 2Division of Gastroenterology, Department of Medicine, Örebro University Hospital, Örebro University, Örebro, 3School of Health and Medical Science, Örebro University, Örebro, 4Division of Gastroenterology, Department of Clinical Science, Lund University, Malmö, Sweden *These authors are members of the Swedish Organization for the study of Inflammatory Bowel Disease (SOIBD, a national organization for gastroenterologists, colorectal surgeons, and basic scientists Background: In most cases, collagenous colitis can be treated effectively with budesonide. However, some patients develop side effects or have chronic symptoms refractory to budesonide. This paper reports an open case series of patients intolerant or refractory to budesonide who were treated with methotrexate (MTX. Methods and patients: Nine patients (seven women with a median (range age of 62 (44–77 years were studied. Bowel movements were registered during 1 week prior to baseline and after 6 and 12 weeks’ treatment, enabling calculation of the mean bowel movements/day. All patients underwent colonoscopy with biopsies before inclusion to confirm diagnosis. Open treatment with MTX was given 15 mg subcutaneously weekly for 6 weeks and was increased to 25 mg for a further 6 weeks if symptoms were unresponsive to the first 6 weeks’ treatment. The endpoint was clinical remission, which was defined as a mean <3 stools/day and mean <1 watery stool/day/week at Week 12. The Short Health Scale was used at baseline and Week 12 to assess health-related quality of life. Results: Five patients fulfilled the treatment according to the protocol and four patients discontinued the study after 3–6 weeks because of adverse events. No patient achieved

  18. Slurry wear characteristics of zinc-based alloys: Effects of sand content of slurry, silicon addition to alloy system and traversal distance

    Institute of Scientific and Technical Information of China (English)

    B.K. PRASAD; O.P. MODI

    2009-01-01

    This investigation deals with the observations pertaining to the effects of specimen and slurry compositions as well as traversal distance on the slurry wear response of a zinc-based alloy. The composition of the alloy was altered by adding 4% silicon to it. The slurry composition was varied through changing the concentration of the sand particles in the range of 0-60% that were suspended in the (liquid) electrolyte. The electrolyte contained 4 g sodium chloride and 5 mL concentrated sulphuric acid dissolved in 10 L of water. The slurry wear tests were conducted at a speed of 7.02 m/s over the traversal distance range of 15-500 km. The wear rate increased initially with traversal distance, attained a maximum and decreased thereafter irrespective of the specimen and test environment. However, the wear rate peaks were less prominent in the liquid plus sand environments than the liquid-only medium. Further, the wear rate peak in the liquid-only medium appeared at a shorter traversal distance than the one in the sand containing slurries. Addition of sand particles to the electrolyte reduced the wear rate of the samples to 5%-15% depending on the sand concentration of the slurry. Moreover, intermediate (40%) sand content led to a maximum wear rate when compared with in the liquid plus sand media. However, this maximum was still less than in the liquid-only medium. The silicon containing alloy suffered from higher wear rates than the silicon free alloy samples when tested in the liquid-only medium. On the contrary, the trend reversed in liquid plus 20% and 40% sand environments whereas a mixed response was noted in the slurry containing 60% sand. In the latter case, the presence of silicon proved deleterious initially while an opposite trend was observed at longer traversal distances. The wear response of the samples was discussed in terms of specific features of their microconstituents like silicon and the predominant material removal mechanism in a given set of

  19. Effect of naphtha diluent on greenhouse gases and reduced sulfur compounds emissions from oil sands tailings.

    Science.gov (United States)

    Gee, Kathleen F; Poon, Ho Yin; Hashisho, Zaher; Ulrich, Ania C

    2017-11-15

    The long-term storage of oil sands tailings has resulted in the evolution of greenhouse gases (CH4 and CO2) as a result of residual organics biodegradation. Recent studies have identified black, sulfidic zones below the tailings-water interface, which may be producing toxic sulfur-containing gases. An anaerobic mesocosm study was conducted over an 11-week period to characterize the evolution of CH4, CO2 and reduced sulfur compounds (RSCs) (including H2S) in tailings as it relates to naphtha-containing diluent concentrations (0.2, 0.8, and 1.5% w/v) and microbial activity. Our results showed that RSCs were produced first at 0.12μmol°RSCs/mL MFT (1.5% w/v diluent treatment). RSCs contribution (from highest to lowest) was H2S and 2-methylthiophene>2.5-dimethylthiophene>3-methylthiophene>thiofuran>butyl mercaptan>carbonyl sulfide, where H2S and 2-methylthiophene contributed 81% of the gas produced. CH4 and CO2 production occurred after week 5 at 40.7μmolCH4/mL MFT and 5.9μmolCO2/mL MFT (1.5% w/v diluent treatment). The amount of H2S and CH4 generated is correlated to the amount of diluent present and to microbial activity as shown by corresponding increases in sulfate-reducers' Dissimilatory sulfite reductase (DsrAB) gene and methanogens' methyl-coenzyme M reductase (MCR) gene. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. An experimental investigation of the independent effect of suction and degree of saturation on very small-strain stiffness of unsaturated sand

    Directory of Open Access Journals (Sweden)

    Pagano Arianna

    2016-01-01

    Full Text Available The paper presents an experimental investigation of very small strain stiffness of unsaturated sand. A triaxial test apparatus was equipped with bender elements and compression discs in order to assess the stiffness at very small strains by measuring the velocity of propagation of shear and compression waves through an unsaturated sample. The negative water column method was adopted to apply suction at the base of the sample. The experiments were designed to investigate the independent effect of suction and degree of saturation on the wave propagation velocities. This was achieved by testing the sand sample on both the drying and wetting path.

  1. Lack of effects of a "sobering" product, "Eezup!", on the blood ethanol and congener alcohol concentration.

    Science.gov (United States)

    Wunder, Cora; Hain, Sarah; Koelzer, Sarah C; Paulke, Alexander; Verhoff, Marcel A; Toennes, Stefan W

    2017-09-01

    The lifestyle product 'Eezup!' appeared on the German market and promised to normalize energy metabolism. Among vitamins (B1, B2, B6, C, E and zinc), rice protein and fructose the addition of alcohol dehydrogenase and catalase enzymes is a novel approach. The product was advertised as capable of boosting the rate of alcohol elimination. Seventeen subjects (11 men, 6 women, 19-58 years old), participated in a two-way crossover drinking study. Unfiltered wheat beer (4.4g% alcohol content) was drank within one hour to reach blood alcohol concentrations of 1‰ (1g/kg whole blood). On one day "Eezup!" was taken according to the manufacturer's instructions before and after drinking which was substituted for a placebo on the second test day. Blood samples were taken during 9h and ethanol and congener alcohols were determined. A comparison of Cmax, tmax, area under the curve (AUC) for ethanol and congener alcohols, and the hourly elimination rate of ethanol (β60) was performed to investigate an effect of Eezup!. Ethanol concentrations (Cmax) were in the range of 0,63-1,00‰ (median 0,85‰) and 0.62-1.22‰ (median 0.84‰) in the placebo and "Eezup!" condition, respectively, and not statistically different. Also tmax (1-2.5h) and AUCs did not differ. The ethanol elimination rates were 0.16‰/h (0.14-0.19‰/h) and 0.17‰/h (0.14-0.22 ‰/h) in the placebo and "Eezup!" condition without significant difference. The pharmacokinetic parameters of the congener alcohols (1-propanol, isobutanol, 3-methyl-1-butanol, 2-methyl-1-butanol) as well as of methanol did also not differ. The results of the present study failed to show any effect of the sobering product "Eezup!" on the amount of ethanol and congener alcohols absorbed (Cmax, tmax, AUC) and on the ethanol elimination rate (β60). Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Lack of preventive effects of dietary fibers or chlorophyllin against acrylamide toxicity in rats.

    Science.gov (United States)

    Woo, Gye-Hyeong; Shibutani, Makoto; Kuroiwa, Keiko; Lee, Kyoung-Youl; Takahashi, Miwa; Inoue, Kaoru; Fujimoto, Hitoshi; Hirose, Masao

    2007-08-01

    Dietary fibers and chlorophyllin have shown to exert anti-carcinogenic effects against co-administered carcinogens. To test the possibility of chemoprevention by such dietary supplements on subacutely induced acrylamide (ACR) toxicity, Sprague-Dawley male rats were administered 2.5% sodium alginate, 5% glucomannan, 5% digestion resistant maltodextrin, 2.5% chitin or 1% chlorophyllin in the diet, and starting one week later, co-administered 0.02% ACR in the drinking water for 4 weeks. For comparison, untreated control animals given basal diet and tap water were also included. Neurotoxicity was examined with reference to gait abnormalities and by quantitative assessment of histopathological changes in the sciatic and trigeminal nerves, as well as aberrant dot-like immunoreactivity for synaptophysin in the cerebellar molecular layer. Testicular toxicity was assessed by quantitation of seminiferous tubules with exfoliation of germ cells into the lumen and cell debris in the ducts of the epididymides. Development of testicular toxicity as well as neurotoxicity was evident with ACR-treatment, but was not suppressed by dietary addition of fibers or chlorophyllin, suggesting no apparent beneficial influence of these dietary supplements on experimentally induced subacute ACR toxicity.

  3. Lack of effect of intranigral transplants of a GABAergic cell line on absence seizures.

    Science.gov (United States)

    Castillo, Claudia G; Mendoza, Soledad; Saavedra, Josie; Giordano, Magda

    2010-08-01

    The substantia nigra pars reticulata (SNpr) is involved in controlling a variety of seizure phenomena. Intranigral transplants of GABAergic cells have been shown to decrease the severity of already established epileptic seizures, but the effects observed have been short-lived. This study evaluated the ability of intranigral transplants of GABA-producing cells to reduce spontaneous absence seizures in a genetic animal model for periods up to 3 months after transplantation. Intranigral transplants did not induce any behavioral deficits in the animals, and they did not form tumors; however, the transplants failed to decrease absence seizures in the genetic model. The assumed increase in intranigral levels of GABA after the transplants may be insufficient to counteract all the factors involved in generating the absence seizures; in this animal model, it may be necessary to further decrease nigral activity by implanting GABAergic cells in another area. These results bear down on the fact that cell transplants need to be tailored for each type of convulsive disorder in terms of the type of cells delivered and the location of the transplants.

  4. Acidic-phosphoprotein phosphatase activity of rat ventral prostate nuclei: apparent lack of effect of androgens.

    Science.gov (United States)

    Wilson, M J; Ahmed, K; Fischbach, T J

    1978-08-01

    A protein phosphatase activity has been demonstrated in nuclei of rat ventral prostate utilizing 32P-labelled phosvitin as a model acidic phosphoprotein substrate. This phosphoprotein phosphatase has a pH optimum of 6.7, is unaffected by the sulphydryl protecting agent 2-mercaptoethanol, and requires a divalent cation for maximal activity. Of the various divalent cations tested, Mg2+ is the most effective in reactivating the EDTA-inhibited enzyme. The phosphatase is inhibited by sodium flouride, sodium oxalate, N-ethylmaleimide, ATP and ADP but is relatively insensitive to ammonium molybdate. Increased ionic strength of the reaction medium also causes a reduction in the enzyme activity, e.g., by 48% at 200 mM sodium chloride. The activity of the acidic phosphoprotein phosphatase did not change significantly at 48 h or 96 h post-orchiectomy when expressed per unit of nuclear protein. However, it is reduced by approx. 30% at these times after castration if based on DNA content. The decline in activity per nucleus reflects the decrease in the realtive nuclear protein content observed at 48 h or 96 h post-orchiectomy. This suggests that the decline in the phosphorylation of prostatic nuclear acidic proteins which occurs upon androgen withdrawal is not due to increased nuclear phosphatase activity.

  5. KIR-HLA genotypes in HIV-infected patients lacking immunological recovery despite effective antiretroviral therapy.

    Directory of Open Access Journals (Sweden)

    Alessandro Soria

    Full Text Available BACKGROUND: In HIV-infected individuals, mechanisms underlying unsatisfactory immune recovery during effective combination antiretroviral therapy (cART have yet to be fully understood. We investigated whether polymorphism of genes encoding immune-regulating molecules, such as killer immunoglobulin-like receptors (KIR and their ligands class I human leukocyte antigen (HLA, could influence immunological response to cART. METHODS: KIR and HLA frequencies were analyzed in 154 HIV-infected and cART-treated patients with undetectable viral load divided into two groups: 'immunological non responders' (INR, N = 50, CD4(+ T-cell count 350/mm(3. Molecular KIR were typed using polymerase chain reaction-based genotyping. Comparisons were adjusted for baseline patient characteristics. RESULTS: The frequency of KIR2DL3 allele was significantly higher in FR than in INR (83.7% vs. 62%, P = 0.005. The functional compound genotype HLA-C1(+/KIR2DL3(+, even at multivariable analysis, when adjusted for nadir CD4(+ T-cell count, was associated with reduced risk of INR status: odds ratio (95% Confidence Intervals 0.34 (0.13-0.88, P = 0.03. CONCLUSIONS: Reduced presence of the inhibitory KIR2DL3 genotype detected in INR might provoke an imbalance in NK function, possibly leading to increased immune activation, impaired killing of latently infected cells, and higher proviral burden. These factors would hinder full immune recovery during therapy.

  6. Lack of effect of amisulpride on the pharmacokinetics and safety of lithium.

    Science.gov (United States)

    Canal, Muriel; Legangneux, Eric; van Lier, Jan Jaap; van Vliet, Andre Antonius; Coulouvrat, Catherine

    2003-06-01

    Lithium may be used as adjuvant therapy in schizophrenic patients and antipsychotics can be employed during the early phases of lithium therapy in patients with bipolar disorder. The issue of interactions between lithium and antipsychotics is therefore important. This study investigates the potential influence of repeated administration of amisulpride, an atypical antipsychotic, on the pharmacokinetics of lithium at steady state. Twenty-four healthy male volunteers (aged 1833 yr) received lithium carbonate (500 mg b.i.d.) for 14 d. All subjects were shown to have stable lithium serum concentrations after 57 d and were then randomized to receive double-blind administration of amisulpride (100 mg b.i.d.) or placebo bid from day 8 of lithium administration. Complete pharmacokinetic profiles were obtained on days 7 and 14 for lithium and trough plasma concentrations on days 10, 12 and 14 for amisulpride. Co-administration of amisulpride appeared to exert no effect on the pharmacokinetics of lithium. All treatments were well tolerated and safety assessment revealed no differences between the lithium+placebo and lithium+amisulpride groups. This finding permits the flexible use of amisulpride in patients already receiving lithium therapy.

  7. Lack of effect of Theiler's murine encephalomyelitis virus infection on system xc⁻.

    Science.gov (United States)

    Merckx, Ellen; Demuyser, Thomas; Bentea, Eduard; Van Liefferinge, Joeri; Albertini, Giulia; Deneyer, Lauren; Michiels, Thomas; Massie, Ann

    2015-04-23

    Changes in the expression of xCT, the specific subunit of system xc(-) or the cystine/glutamate antiporter, have been associated with several neurological disorders and system xc(-) was recently proposed as a potential target for the development of new treatment strategies for multiple sclerosis (MS). In this study we used Theiler's murine encephalomyelitis virus (TMEV) infection, both in vitro and in vivo, as a model to further evaluate the involvement of system xc(-) in MS. Protein levels of xCT, as well as activity of system xc(-) were unaffected in RAW264.7 macrophages after infection with the demyelinating DA strain of TMEV. Also, protein expression of xCT remained stable in spinal cord and brain of FVB mice 1-2 and 6 weeks after intracranial injection of the DA strain of TMEV. These results demonstrate that TMEV infection of macrophages or FVB mice has no effect on system xc(-) and as such cannot be used as a model to study the involvement of system xc(-) in MS.

  8. Lack of effect of chronic dextromethorphan on experimental pain tolerance in methadone-maintained patients

    Science.gov (United States)

    Compton, Peggy A.; Ling, Walter; Torrington, Matt A.

    2014-01-01

    Good evidence exists to suggest that individuals on opioid maintenance for the treatment of addiction (i.e. methadone) are less tolerant of experimental pain than are matched controls or ex-opioid addicts, a phenomenon theorized to reflect opioid-induced hyperalgesia (OIH). Agonist activity at the excitatory ionotropic N-methyl-D-aspartate (NMDA) receptor on dorsal horn neurons has been implicated in the development of both OIH and its putative expression at the clinical level—opioid tolerance. The aim of this study was to evaluate the potential utility of the NMDA-receptor antagonist, dextromethorphan (DEX), to reverse or treat OIH in methadone-maintenance (MM) patients. Utilizing a clinical trial design and double-blind conditions, changes in pain threshold and tolerance [cold pressor (CP) and electrical stimulation (ES)] following a 5-week trial of DEX (titrated to 480 mg/day) in comparison with placebo was evaluated in a well-characterized sample of MM patients. The sample (n = 40) was 53% male and ethnically diverse (53% Latino, 28% African American, 10% White, 9% other), with a mean age of 48.0 years (SD = 6.97). Based on t-test analyses, no difference was found between groups on CP pain threshold, CP pain tolerance, ES pain threshold or ES pain tolerance, both pre- and postmedication. Notably, DEX-related changes significantly differed by gender, with women tending to show diminished tolerance for pain with DEX therapy. These results support that chronic high-dose NMDA antagonism does not improve tolerance for pain in MM patients, although a gender effect on DEX response is suggested. PMID:18507735

  9. Lack of effect of intravaginal dehydroepiandrosterone (DHEA, prasterone) on the endometrium in postmenopausal women.

    Science.gov (United States)

    Portman, David J; Labrie, Fernand; Archer, David F; Bouchard, Céline; Cusan, Leonello; Girard, Ginette; Ayotte, Normand; Koltun, William; Blouin, François; Young, Douglas; Wade, Anthony; Martel, Céline; Dubé, Robert

    2015-12-01

    This study aims to evaluate the effects of intravaginal dehydroepiandrosterone (DHEA, prasterone) on the endometrium in postmenopausal women. Intravaginal DHEA (6.5 mg) was administered daily for 52 weeks to 422 women who had endometrial biopsy at baseline and end of study, whereas 15 women were similarly treated for 26 to 52 weeks. Participants in three other studies received 3.25 mg (n = 126), 6.5 mg (n = 129), or 13 mg (n = 30) of DHEA for 12 weeks; women similarly had baseline and end-of-study biopsies. Endometrial biopsy samples were available for 668 women at baseline and end of study, with sufficient material for analysis. Endometrial atrophy or inactive endometrium (668 women) was found in all women treated with intravaginal DHEA. Similar atrophy was observed in 119 of 121 participants with sufficient material for analysis who received placebo. After cessation of estradiol secretion by the ovaries at menopause, the estrogens made by mechanisms of intracrinology are inactivated intracellularly at their site of formation and action, thus maintaining serum estradiol at biologically inactive concentrations to avoid stimulation of the endometrium. The absence of enzymes that are able to transform DHEA into estrogens in the endometrium explains the typical endometrial atrophy in all normal postmenopausal women in the presence of variable concentrations of circulating endogenous DHEA. According to these mechanisms, the inactive sex steroid precursor DHEA administered intravaginally acts exclusively in the vagina, whereas all serum sex steroids remain well within the biologically inactive postmenopausal reference range, thus avoiding any stimulation of the already atrophic endometrium.

  10. Lack of genotoxic effect in workers exposed to very low doses of 1,3-butadiene.

    Science.gov (United States)

    Lovreglio, Piero; Bukvic, Nenad; Fustinoni, Silvia; Ballini, Andrea; Drago, Ignazio; Foà, Vito; Guanti, Ginevra; Soleo, Leonardo

    2006-06-01

    1,3-Butadiene (BD), a probable carcinogen to humans, has been shown to have an ill-defined genotoxicity in occupationally exposed workers. In the present study, the influence of exposure to very low doses of BD and to cigarette smoking was investigated on some cytogenetic endpoints, namely, sister chromatid exchanges (SCE), chromosomal aberrations (CA) and cells with a high frequency of SCE (HFC), in peripheral blood lymphocytes. Twenty-seven male workers employed in a petrochemical plant and 26 matched controls were included in the study. As regards the airborne BD values, there was a significant difference between exposed (median BD value 1.5, min-max 0.2-69.0 microg/m3) and non-exposed workers (median BD value 0.4, min-max <0.1-3.8 microg/m3). Genotoxic biomarkers were not able to distinguish between the two groups. The frequency of SCE was higher in smokers than in non-smokers (p=0.001), with a positive correlation between the number of cigarettes smoked per day and both SCE (r=0.4; p=0.004) and HFC frequency (r=0.3; p=0.04). Multiple regression analysis confirmed the influence of cigarette smoking on the level of SCE and HFC, while these parameters were not affected by personal exposure to BD. Overall, the biomarkers of genotoxic effect investigated in our study were not able to discriminate between workers with a very low exposure to BD and controls, while it was possible to distinguish between smokers and non-smokers on the basis of SCE.

  11. 2008 Weather and Aeolian Sand-Transport Data from the Colorado River Corridor, Grand Canyon, Arizona

    Science.gov (United States)

    Draut, Amy E.; Sondossi, Hoda A.; Hazel, Joseph E.; Andrews, Timothy; Fairley, Helen C.; Brown, Christopher R.; Vanaman, Karen M.

    2009-01-01

    This report presents measurements of weather parameters and aeolian (windblown) sand transport made in 2008 near selected archaeological sites in the Colorado River corridor through Grand Canyon, Ariz. The quantitative methods and data discussed here form a basis for monitoring ecosystem processes that affect archeological-site stability. Combined with forthcoming work to evaluate landscape evolution at nearby archaeological sites, these data can be used to document the relationship between physical processes, including weather and aeolian sand transport, and their effects on the physical integrity of archaeological sites. Data collected in 2008 reveal event- and seasonal-scale variations in rainfall, wind, temperature, humidity, and barometric pressure. Broad seasonal changes in aeolian sediment flux are also apparent at most study sites. The continuation of monitoring that began in 2007, and installation of equipment at several new sites in early 2008, allowed evaluation of the effects of the March 2008 high-flow experiment (HFE) on aeolian sand transport. At two of the nine sites studied, spring and summer winds reworked 2008 HFE sandbars to form new aeolian dunes, at which sand moved inland toward larger, well-established dune fields. At the other seven study sites, neither dune formation nor enhanced sand transport after the HFE were observed. At several of those sites, dominant wind directions in spring 2008 were not oriented such that much HFE sand would have moved inland; at other sites, lack of increased inland sand flux is attributable to lack of sandbar enlargement near the study sites or to inhibition of sand movement by vegetation or local topography.

  12. Effect of probiotic and sand filtration treatments on water quality and growth of tilapia (Oreochromis niloticus) and pangas (Pangasianodon hypophthalmus) in earthen ponds of southern Bangladesh

    DEFF Research Database (Denmark)

    Mahmud, Sultan; Ali, Mohammad Lokman; Alam, Md Ariful

    2016-01-01

    Effects of water treatment by two probiotic products (PondPlus® and AquaPhoto®) and sand filtration were studied on growth performance of tilapia (Oreochromis niloticus) and pangas (Pangasianodon hypophthalmus) stocked at tilapia:pangas ratio of 5:3 in traditional earthen ponds in Bangladesh...

  13. Effects of Sand Harvesting on Environment and Educational Outcomes in Public Primary Schools in Kathiani Sub-County, Machakos County, Kenya

    Science.gov (United States)

    Nthambi, Mutiso Veronicah; Orodho, John Aluko

    2015-01-01

    The purpose of this study was to examine the effects of sand harvesting on environment and educational outcomes in public primary schools in Kathiani Sub-County, Machakos County, Kenya. This study was premised on treadmill theory of production proposed by Schnaiberg (1980). The study adopted a survey design. Combinations of purposive and…

  14. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  15. The Effects of Particle Morphology (Shape and Sizes Characteristics on its Engineering Behaviour and Sustainable Engineering Performance of Sand

    Directory of Open Access Journals (Sweden)

    Meng Siang Lim

    2013-02-01

    Full Text Available The mechanical behaviour of granular soil is interestingly dependent on the characteristics of the particles. The wide range of particle shapes and size distribution of sand, by virtue of its sedimentological process of formation plays a significant factor in the influence on its engineering behaviour reflected in terms of its packing density, permeability, shear strength and dilatancy. In this study, research on well graded sand (SW, poorly graded uniform sand (SPuKahang, gap graded sand (SPg from Kahang Malaysia and also (SPuL.Buzzard Leighton Buzzard sand from UK were tested in a direct shear box. The shapes were quantified using images from a digital microscope where its morphological features can lead via statistical methods to determined correlations between strength and its physical properties. The research effort focuses in obtaining its shear strength and roughness parameters and also its extreme packing (emin and emax. Results from published studies on related matter and also the study on permeability are presented. The findings would lead to a better way to classify the shape and size distribution for the assessment of the behaviour of sand in various engineering disciplines such a good foundation soil in geotechnical engineering, as an abrasive material in mechanical engineering, as a filler of concrete in civil engineering, as a filter in chemical engineering and occurs as oil sands in petroleum engineering.

  16. Lack of effect of flurothyl, a non-anesthetic fluorinated ether, on rat brain synaptic plasma membrane calcium-ATPase.

    Science.gov (United States)

    Horn, J L; Janicki, P K; Franks, J J

    1999-01-01

    Plasma membrane Ca2+-ATPase (PMCA), a regulator of intracellular calcium, is inhibited by volatile anesthetics and by xenon and nitrous oxide. Response of a cellular system to anesthetics, particularly to volatile agents, raises the question of non-specific, even toxic, side effects unrelated to anesthetic action. Compounds with chemical and physical properties similar to halogenated anesthetics, but which lack anesthetic effect, have been used to address this question. We have compared the effects of halothane and flurothyl, a non-anesthetic fluorinated ether, on PMCA Ca2+ transport across isolated brain synaptic plasma membranes (SPM). Flurothyl, at concentrations predicted by the Meyer-Overton curve to range from 0.4 to 2.6 MAC (minimum alveolar concentration), had no significant on PMCA activity. In contrast halothane, 1.3 MAC, reduced Ca2+ transport 30 to 40%. These findings provide further evidence for a specific effect of inhalation anesthetics on neuronal plasma membrane Ca2+-ATPase.

  17. Influence green sand system by core sand additions

    OpenAIRE

    N. Špirutová; J. Beňo; V. Bednářová; J. Kříž; M. Kandrnál

    2012-01-01

    Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron) are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this co...

  18. Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Borup, Marianne; Hedegaard, Jette

    The Soil Mechanics Laboratory has started performing tests with a new sand, Baskarp No 15. Baskarp No 15 is a graded sand from Sweden. The shapes of the largest grains are round, while the small grains have sharp edges. The main part of of Baskarp No 15 is quarts, but it also contains feldspar...... and biotit. Mainly the sand will be used for tests concerning the development og the theory of building up pore pressure in sand, L. B. Ibsen 1993....

  19. Effective treatment of perinatal depression for women in debt and lacking financial empowerment in a low-income country.

    Science.gov (United States)

    Rahman, Atif; Sikander, Siham; Malik, Abid; Ahmed, Ikhlaque; Tomenson, Barbara; Creed, Francis

    2012-12-01

    Poverty may moderate the effect of treatment of depression in low-income countries. To assess poverty and lack of empowerment as moderators of a cognitive-behavioural therapy (CBT)-based intervention for perinatal depression in rural Pakistan. Using secondary analysis of data from a randomised controlled trial (trial registration: ISRCTN65316374) we identified predictors of depression at 1-year follow-up and moderators of the intervention (n = 791). Predictors of follow-up depression included household debt, the participant not being empowered to manage household finance and the interaction terms for these variables with the trial arm. Effect sizes for women with and without household debt were 0.80 and 0.55 respectively. The effect size for women in debt and not empowered financially was 0.94 compared with 0.50 for women with neither of these factors. Our findings demonstrate the importance of household debt and lack of financial empowerment of women as important maintaining factors of depression in low-income countries and our locally developed intervention tackled these problems successfully.

  20. Lund Sand No 0

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Jakobsen, Finn Rosendal

    During the last 15 years the Geotechnical Engineering Group (GEG) at Aalborg University has performed triaxial tests with a sand called Lund No 0. Lund No 0 is a graded sand from a gravel pit near Horsens in Denmark. For the classification of the sand the following tests have been performed: Sieve...

  1. Population differentiation and the effects of herbivory and sand compaction on the subterranean growth of a desert lily.

    Science.gov (United States)

    Ruiz-R, Natalia; Ward, David; Saltz, David

    2006-01-01

    Differences in level of herbivory can select for local adaptation and genetic differentiation of plant populations in different environments. Mean bulb depth of the desert lily Pancratium sickenbergeri, differs considerably among populations differing in the level of herbivory by the dorcas gazelle. The gazelle digs in the sand to remove most of the bulb of the lily. Deeper bulbs have less material removed by herbivory than shallow bulbs and have higher fitness. A possible confounding factor is the degree of sand compaction, which may retard the downward growth of the bulb. We conducted a common garden experiment with 2 sand types with seeds from source populations with different levels of herbivory. There was a large genetic difference among populations. Two of 3 analyses indicated that there was an interaction between population and sand type, indicating that there is a heritable component of plasticity.

  2. Sand transportation and reverse patterns over leeward face of sand dune

    Science.gov (United States)

    Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

    2017-04-01

    Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

  3. Sand Failure Mechanism and Sanding Parameters in Niger Delta Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Sunday Isehunwa,

    2010-05-01

    Full Text Available Sand production is a major issue during oil and gas production from unconsolidated reservoirs. In predicting the onset of sand production, it is important to accurately determine the failure mechanism and the contributing parameters. The aim of this study was to determine sand failure mechanism in the Niger-Delta, identify themajor contributing parameters and evaluate their effects on sanding.Completion and production data from 78 strings completed on 22 reservoirs in a Niger Delta oil Field were evaluated. Sand failure mechanisms and contributing parameters were identified and compared with published profiles. The results showed that cohesive stress is the predominant sand failure mechanism. Water cut, bean size and gas oil ratio (GOR impact sand production in the Niger Delta.

  4. Experimental effects of sand-dust storm on tolerance index, percentage phototoxicity and chlorophyll a fluorescence of Vigna radiata L.

    Directory of Open Access Journals (Sweden)

    M. Alavi

    2015-03-01

    Full Text Available In arid and semi-arid parts of the world excessive mineral aerosol carried by air parcels is a common climatic incident with well-known environmental side effects. In this way, we studied the role of sand-dust accumulation on various aspects of productivity of Vigna radiata L. including dry mass (DM, chlorophyll (Chl a, b, Chlorophyll a fluorescence (effective quantum yield of PSII photochemistry (ФPSII, maximal quantum yield of PSII photochemistry (Fv/Fm and electron transport rate (ETR. V. radiata was exposed to a gradient of dust concentrations in a dust chamber (0.5 (T1, 1(T2 and 1.5 g/m3 (T3 simulated by a dust generator for a period of 60 days. Results of this experiment indicate that DM and Chl content of shoot are negatively correlated with the intensity of the dust exposure. Exposure of V. radiata to dust compared with the control was caused 5% (T1, 14% (T2 and 27% (T3 reduction in leaf DM (p≤0.05, ANOVA. Also, exposure to the dust induced a significant (p≤0.05 reduction in the Total Chl content in (T3 25%. Also, we showed that ФPSII, ETR and Fv/Fm were affected by increasing of the dust concentrations. Exposure to the dust resulted in a significant reduction in ETR of 15%, 22%, and 43%.

  5. Metabolic emergent auditory effects by means of physical particle modeling : the example of musical sand

    OpenAIRE

    Luciani, Annie; Castagné, Nicolas; Tixier, Nicolas

    2003-01-01

    International audience; In the context of Computer Music, physical modeling is usually dedicated to the modeling of sound sources or physical instruments. This paper presents an innovative use of physical modeling in order to model and synthesize complex auditory effects such as collective acoustic phenomena producing metabolic emergent auditory organizations. As a case study, we chose the "dune effect", which in open nature leads both to visual and auditory effects. The article introduces tw...

  6. Optimal array of sand fences.

    Science.gov (United States)

    Lima, Izael A; Araújo, Ascânio D; Parteli, Eric J R; Andrade, José S; Herrmann, Hans J

    2017-03-24

    Sand fences are widely applied to prevent soil erosion by wind in areas affected by desertification. Sand fences also provide a way to reduce the emission rate of dust particles, which is triggered mainly by the impacts of wind-blown sand grains onto the soil and affects the Earth's climate. Many different types of fence have been designed and their effects on the sediment transport dynamics studied since many years. However, the search for the optimal array of fences has remained largely an empirical task. In order to achieve maximal soil protection using the minimal amount of fence material, a quantitative understanding of the flow profile over the relief encompassing the area to be protected including all employed fences is required. Here we use Computational Fluid Dynamics to calculate the average turbulent airflow through an array of fences as a function of the porosity, spacing and height of the fences. Specifically, we investigate the factors controlling the fraction of soil area over which the basal average wind shear velocity drops below the threshold for sand transport when the fences are applied. We introduce a cost function, given by the amount of material necessary to construct the fences. We find that, for typical sand-moving wind velocities, the optimal fence height (which minimizes this cost function) is around 50 cm, while using fences of height around 1.25 m leads to maximal cost.

  7. Effect of sand bed depth and media age on Escherichia coli and turbidity removal in biosand filters.

    Science.gov (United States)

    Napotnik, Julie A; Baker, Derek; Jellison, Kristen L

    2017-02-17

    The main objective of this study was to build several full-scale biosand filters (BSFs) and assess the long-term (9 month) efficacy for particulate and Escherichia coli removal under simulated real-world usage. Four replicates of three different filter designs were built: the traditional concrete BSF, and two scaled-down versions that use a 5-gal or 2-gal bucket, respectively, as the casing material. The smaller sand bed depths in the bucket-sized filters did not impact filter performance with respect to (i) turbidity and E. coli removal or (ii) effluent levels of turbidity and E. coli. All filters produced effluents with a mean turbidity of <0.6 NTU. In addition, 78%, 74%, and 72% of effluent samples for the concrete, 5-gal, and 2-gal filters, respectively, had E. coli concentrations <1 CFU/100 mL. The bucket-sized filters were found to be a potential alternative to the concrete BSFs for the removal of E. coli and turbidity from drinking water. Since smaller BSFs must be filled more frequently than larger BSFs to produce comparable water volumes, the effect of shorter pause periods on BSF performance should be investigated.

  8. Extraction of bitumen, crude oil and its products from tar sand and contaminated sandy soil under effect of ultrasound.

    Science.gov (United States)

    Abramov, O V; Abramov, V O; Myasnikov, S K; Mullakaev, M S

    2009-03-01

    In the present paper, the kinetics of the water extraction of bitumen from tar sand and crude oil or residual fuel oil from model contaminated soils under the effect of ultrasound is studied. The influence of process temperature, ultrasound power, the nature, and properties of the components of heterogeneous mixtures being separated, and the concentration of added alkaline reagents on the rate and degree of oil recovery is investigated. A functional form of the dependencies of separation efficiency on the mean size of solid particles and the temperature of a working medium is found. Optimum concentrations of reagents in the process solution are determined. It is shown that the spent solution of sodium silicate can be multiply used for separation, its reuse even speeding up the yield of oil in the initial period. Taking into account obtained results, a multipurpose pilot plant with a flow-type reactor for ultrasonic extraction of petroleum and its products from contaminated soils was manufactured and tested. During tests, the purification of sandy soil contaminated with residual fuel oil was carried out which verified the results of laboratory studies.

  9. Effectiveness of a full-scale horizontal slow sand filter for controlling phytopathogens in recirculating hydroponics: From microbial isolation to full microbiome assessment.

    Science.gov (United States)

    Prenafeta-Boldú, Francesc X; Trillas, Isabel; Viñas, Marc; Guivernau, Miriam; Cáceres, Rafaela; Marfà, Oriol

    2017-12-01

    The microbial disinfestation efficiency of an innovative horizontal-flow slow sand filter (HSSF) for treating nutrient solution spent from an experimental closed-loop nursery was evaluated by means of a combination of culture-dependent and independent molecular techniques. A dense inoculum of the fungal plant pathogen Fusarium oxysporum f.sp. lycopersici was applied in the fertigation system (10(6) cells per mL). Indigenous and introduced populations of eubacteria and fungi were assessed in the nutrient solution, the HSSF influent/effluent, and a sand bed transect by isolation on selective media, as well as by quantitative qPCR and next-generation sequencing (NGS) on target ribosomal genes. The HSSF effectively reduced viable Fusarium propagules and fungal gene content with an efficiency consistently above 99.9% (5 orders of magnitude down). On the other hand, Fusarium cells accumulated in the sand bed, indicating that physical entrapment was the main removal mechanism. The viability of retained Fusarium cells tended to decrease in time, so that treatment efficiency might be enhanced by antagonistic species from the genera Bacillus, Pseudomonas, and Trichoderma, also identified in the sand bed. Indigenous bacterial populations from the HSSF effluent were reduced by 87.2% and 99.9% in terms of colony forming units and gene counts, respectively, when compared to the influent. Furthermore, microbial populations from the HSSF effluent were different from those observed in the sand bed and the influent. In summary, the HSSF microbial disinfestation efficiency is comparable to that reported for other more intensive and costly methodologies, while allowing a significant recovery of water and nutrients. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Critical state of sand matrix soils.

    Science.gov (United States)

    Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

    2014-01-01

    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803-0.998, 0.144-0.248, and 1.727-2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

  11. Critical State of Sand Matrix Soils

    Directory of Open Access Journals (Sweden)

    Aminaton Marto

    2014-01-01

    Full Text Available The Critical State Soil Mechanic (CSSM is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

  12. Global sand trade is paving the way for a tragedy of the sand commons

    Science.gov (United States)

    Torres, A.; Brandt, J.; Lear, K.; Liu, J.

    2016-12-01

    In the first 40 years of the 21st century, planet Earth is highly likely to experience more urban land expansion than in all of history, an increase in transportation infrastructure by more than a third, and a great variety of land reclamation projects. While scientists are beginning to quantify the deep imprint of human infrastructure on biodiversity at large scales, its off-site impacts and linkages to sand mining and trade have been largely ignored. Sand is the most widely used building material in the world. With an ever-increasing demand for this resource, sand is being extracted at rates that far exceed its replenishment, and is becoming increasingly scarce. This has already led to conflicts around the world and will likely lead to a "tragedy of the sand commons" if sustainable sand mining and trade cannot be achieved. We investigate the environmental and socioeconomic interactions over large distances (telecouplings) of infrastructure development and sand mining and trade across diverse systems through transdisciplinary research and the recently proposed telecoupling framework. Our research is generating a thorough understanding of the telecouplings driven by an increasing demand for sand. In particular, we address three main research questions: 1) Where are the conflicts related to sand mining occurring?; 2) What are the major "sending" and "receiving" systems of sand?; and 3) What are the main components (e.g. causes, effects, agents, etc.) of telecoupled systems involving sand mining and trade? Our results highlight the role of global sand trade as a driver of environmental degradation that threatens the integrity of natural systems and their capacity to deliver key ecosystem services. In addition, infrastructure development and sand mining and trade have important implications for other sustainability challenges such as over-fishing and global warming. This knowledge will help to identify opportunities and tools to better promote a more sustainable use

  13. A discrete particle approach to simulate the combined effect of blast and sand impact loading of steel plates

    Science.gov (United States)

    Børvik, T.; Olovsson, L.; Hanssen, A. G.; Dharmasena, K. P.; Hansson, H.; Wadley, H. N. G.

    2011-05-01

    The structural response of a stainless steel plate subjected to the combined blast and sand impact loading from a buried charge has been investigated using a fully coupled approach in which a discrete particle method is used to determine the load due to the high explosive detonation products, the air shock and the sand, and a finite element method predicts the plate deflection. The discrete particle method is based on rigid, spherical particles that transfer forces between each other during collisions. This method, which is based on a Lagrangian formulation, has several advantages over coupled Lagrangian-Eulerian approaches as both advection errors and severe contact problems are avoided. The method has been validated against experimental tests where spherical 150 g C-4 charges were detonated at various stand-off distances from square, edge-clamped 3.4 mm thick AL-6XN stainless steel plates. The experiments were carried out for a bare charge, a charge enclosed in dry sand and a charge enclosed in fully saturated wet sand. The particle-based method is able to describe the physical interactions between the explosive reaction products and soil particles leading to a realistic prediction of the sand ejecta speed and momentum. Good quantitative agreement between the experimental and predicted deformation response of the plates is also obtained.

  14. Effects of surfactant treatments on the wettability of a water repellent grass-covered dune sand

    NARCIS (Netherlands)

    Dekker, L.W.; Oostindie, K.; Kostka, S.J.; Ritsema, C.J.

    2005-01-01

    Copper is an important micronutrient and trace amounts are essential for crop growth. However, high concentrations of copper will produce toxic effects. Australia is increasingly developing production of crops in water repellent soils. Clay amendment, a common amelioration techniques used in Austral

  15. Effects of oral administration of type Ⅱ collagen on adjuvant arthritis in rat sand its mechanisms

    Institute of Scientific and Technical Information of China (English)

    胡永秀; 赵文明; 钱娴娟; 张力平

    2003-01-01

    Objective To investigate the effects of oral administration of type Ⅱ collagen (CⅡ) on a djuvant arthritis (AA) in rats and its mechanisms, and to compare the effects of CⅡ with those of the Chinese traditional medicine Tripterygium Polyglycoside a dministered similarly.Methods Arthritis was induced in rats by immunization using Freund's complete adjuvant (FCA). After feeding rats either soluble CⅡ or Tripterygium Polyglycoside, chan ges in degree of articular swelling and articular histological findings were observed in AA rats. Some correlative immunological indexes were measured, includi ng delayed type hypersensitivity (DTH) reaction, anti-collagen and anti-Mycoba cterium tuberculosis (MT) antibody in serum, and levels of IFN-γ and TNF-α i n articular steep in rats.Results Oral administration of CⅡ was able to alleviate both distinctly articular and general symptoms in AA rats, suppress synovium hyperplasia and inflammatory cells infiltration in arthrosis capsule. The effects brought about by CⅡ were stronger than those by Tripterygium Polyglycoside. Oral administration of CⅡ inhibi ted antigen-specific immune response, such as DTH and antibody reaction to CⅡ . In addition, the expression of IFN-γ and TNF-α in joints were locally dow nregulated. Conclusions The therapeutic effect of oral administration of CⅡ is obvious on adjuvant art hritis in rats. Its remedial mechanisms are likely related to the downregulation of both IFN-γ and TNF-α, and the suppression of cell immunity.

  16. Effects of irrigation on sorghum forage yield and quality in the central sands region of Wisconsin

    Science.gov (United States)

    A study was conducted to assess effects of irrigation on yield and quality of photoperiod sensitive (PS) and non-PS forage sorghum, sorghum-sudangrass, and sudangrass in comparison to corn in central Wisconsin. The study was a strip-plot design with a 5 x 8 factorial arrangement of treatments. Five ...

  17. The Effect of Microclimates in the Aeolian Sand Environment at the Mogao Grottoes, China

    Directory of Open Access Journals (Sweden)

    Guo Shuai Li

    2013-01-01

    Full Text Available To study the micro-meteorological effects of different underlying surfaces of structures to protect the Mogao Grottoes, we analyzed basic meteorological measurements collected at weather stations located in front of the grottoes, on top of the grottoes and in the artificial Gobi. The results show that the shelterbelts in front of the grottoes have a heat-retaining effect. The profile of average daily solar radiation in front of the grottoes forms a sharp peak and the profile in the Gobi forms a parabola, but these patterns vary in different seasons. The artificial Gobi was more susceptible to extremes in temperature and had a faster response and wider response range to ground temperature. The average monthly air temperature, average monthly relative humidity, and the average wind speed in the artificial Gobi tend to first decrease and then increase with measurement height.

  18. Experimental Investigation of Effects of Vibration upon Elastic and Cohesive Properties of Beds of Wet Sand

    Directory of Open Access Journals (Sweden)

    S. Alsop

    1995-01-01

    Full Text Available The transmission of sinusoidal vibrations through beds of cohesive particulate solids was measured. Results were interpreted in terms of a critical state model to predict the elastic swelling constant k, and the cohesive stress C. Factorial experimental design was used to identify significant parameters. Factors that affect k include percent moisture, bulk density, sample size, sample shape, the presence of a supporting membrane, and loading order. Factors that affect C include percent moisture and particle size distribution. Factors affecting k were interpreted in terms of their effects upon bed structure and factors affecting C in terms of an equivalent pore water pressure due to capillary and liquid bridge effects. The critical state model was modified to incorporate general relationships between axial and radial strains.

  19. Fiber-reinforced sand strength and dilation characteristics

    Directory of Open Access Journals (Sweden)

    Hesham M. Eldesouky

    2016-06-01

    Full Text Available Randomly distributed fiber reinforcement is used to provide an isotropic increase in the sand shear strength. The previous studies were not consistent regarding the fibers effect on the volumetric change behavior of fiber-reinforced sand. In this paper, direct shear tests are conducted on 108 specimens to investigate the effects of the fibers content, relative density, normal stress and moisture content on the shear strength and volumetric change behaviors of fiber-reinforced sand. The study investigates also the possibility of using dry fiber-reinforced sand as an alternative to heavily compacted unreinforced moist sand. The results indicate that the fibers inclusion increases the shear strength and dilation of sand. Moisture suppresses the fibers effect on the peak and post-peak shear strengths, and dilation. Dry loose fiber-reinforced sand achieves the same shear strength of heavily compacted unreinforced moist sand, yet at more than double the horizontal displacement.

  20. Shape Effect of Crushed Sand Filler on Rheology: A Preliminary Experimental and Numerical Study

    DEFF Research Database (Denmark)

    Spangenberg, Jon; Cepuritis, Rolands; Hovad, Emil

    2016-01-01

    was quantified with the slump flow test (i.e. mini cone). The shape effect was isolated in the experiments by the use of non overlapping bimodal particle distributions of cement particles with a number average diameter of approximate to 0.01 mm and filler particles with a number average diameter of approximate...... classification, and had length/thickness (L/T) aspect ratios of 2.00 and 1.82, respectively. The particles were characterized with X-ray micro-computed tomography, coupled with spherical harmonic analysis to mathematically describe the full 3-D shape of the particles, while the rheological performance...... to 0.1 mm. The two filler types were tested with a range of chi-values (volume of cement divided by total volume of solids). The flowability of the matrix increased with decreasing aspect ratios of the filler. However, the chi-value at which the maximum volume fraction threshold was obtained varied...

  1. Thermal stress analysis method considering geometric effect of risers in sand mold casting process

    Institute of Scientific and Technical Information of China (English)

    S Y Kwak; HY Hwang; C Cho

    2014-01-01

    Solidification and fluid flow analysis using computer simulation is a current common practice. There is also a high demand for thermal stress analysis in the casting process because casting engineers want to control the defects related to thermal stresses, such as large deformation and crack generation during casting. The riser system is an essential part of preventing the shrinkage defects in the casting process, and it has a great influence on thermal phenomena. The analysis domain is dramatical y expanded by attaching the riser system to a casting product due to its large volume, and it makes FEM mesh generation difficult. However, it is difficult to study and solve the above proposed problem caused by riser system using traditional analysis methods which use single numerical method such as FEM or FDM. In this paper, some research information is presented on the effects of the riser system on thermal stress analysis using a FDM/FEM hybrid method in the casting process simulation. The results show the optimal conditions for stress analysis of the riser model in order to save computation time and memory resources.

  2. Fairness heuristics and substitutability effects: inferring the fairness of outcomes, procedures, and interpersonal treatment when employees lack clear information.

    Science.gov (United States)

    Qin, Xin; Ren, Run; Zhang, Zhi-Xue; Johnson, Russell E

    2015-05-01

    Employees routinely make judgments of 3 kinds of justice (i.e., distributive, procedural, and interactional), yet they may lack clear information to do so. This research examines how justice judgments are formed when clear information about certain types of justice is unavailable or ambiguous. Drawing from fairness heuristic theory, as well as more general theories of cognitive heuristics, we predict that when information for 1 type of justice is unclear (i.e., low in justice clarity), people infer its fairness based on other types of justice with clear information (i.e., high in justice clarity). Results across 3 studies employing different designs (correlational vs. experimental), samples (employees vs. students), and measures (proxy vs. direct) provided support for the proposed substitutability effects, especially when inferences were based on clear interactional justice information. Moreover, we found that substitutability effects were more likely to occur when employees had high (vs. low) need for cognitive closure. We conclude by discussing the theoretical contributions and practical implications of our findings. (c) 2015 APA, all rights reserved).

  3. Effects of disturbance on vegetation by sand accretion and erosion across coastal dune habitats on a barrier island.

    Science.gov (United States)

    Miller, Thomas E

    2015-01-12

    Coastal geomorphology and vegetation are expected to be particularly sensitive to climate change, because of disturbances caused by sea-level rise and increased storm frequency. Dunes have critical reciprocal interactions with vegetation; dunes create habitats for plants, while plants help to build dunes and promote geomorphological stability. These interactions are also greatly affected by disturbances associated with sand movement, either in accretion (dune building) or in erosion. The magnitude and intensity of disturbances are expected to vary with habitat, from the more exposed and less stable foredunes, to low-lying and flood-prone interdunes, to the protected and older backdunes. Permanent plots were established at three different spatial scales on St George Island, FL, USA, where the vegetation and dune elevation were quantified annually from 2011 to 2013. Change in elevation, either through accretion or erosion, was used as a measure of year-to-year disturbance over the 2 years of the study. At the scale of different dune habitats, foredunes were found to have the greatest disturbance, while interdunes had the least. Elevation and habitat (i.e. foredune, interdune, backdune) were significantly correlated with plant community composition. Generalized linear models conducted within each habitat show that the change in elevation (disturbance) is also significantly correlated with the plant community, but only within foredunes and interdunes. The importance of disturbance in exposed foredunes was expected and was found to be related to an increasing abundance of a dominant species (Uniola paniculata) in eroding areas. The significant effect of disturbance in the relatively stable interdunes was surprising, and may be due to the importance of flooding associated with small changes in elevation in these low-lying areas. Overall, this study documents changes in the plant community associated with elevation, and demonstrates that the foredune and interdune

  4. Effect of sand blasting on structural, thermal, and mechanical properties of Zr{sub 58.3}Cu{sub 18.8}Al{sub 14.6}Ni{sub 8.3} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Tariq, Naeem ul Haq; Awais, Hasan Bin; Naeem, Muhammad; Shahid, Rub Nawaz [Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan). Dept. of Metallurgy and Materials Engineering; Akhter, Javaid Iqbal [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Physics Div.

    2012-07-15

    In the present work sand-blasting-induced structural, thermal, and mechanical effects were studied in Zr{sub 58.3}Cu{sub 18.8}Al{sub 14.6}Ni{sub 8.3} bulk metallic glass. It was observed that sand blasting favors disordering of the atomic configuration, formation of free volume and evolution of multiple intersecting shear bands. As a result, considerable compressive plasticity was achieved in sand-blasted samples. It was also observed that in order to superimpose the effect of prestraining and extra free volume for improving compressive plasticity, there exists a limit to both parameters. (orig.)

  5. Compaction creep of sands due to time-dependent grain failure : Effects of chemical environment, applied stress, and grain size

    NARCIS (Netherlands)

    Brzesowsky, R. H.; Hangx, S. J. T.; Brantut, N.; Spiers, C. J.

    2014-01-01

    Time-dependent brittle creep plays a role in controlling compaction of sands and sandstones under upper crustal conditions, influencing phenomena such as production-induced reservoir compaction, surface subsidence, and induced seismicity. Brittle creep also plays a role in determining the mechanical

  6. Facilitated transport of Cu with hydroxyapatite nanoparticles in saturated sand: Effects of solution ionic strength and composition

    Science.gov (United States)

    Column experiments were conducted to investigate the facilitated transport of Cu in association with hydroxyapatite nanoparticles (nHAP) in water-saturated quartz sand at different solution concentrations of NaCl (0 to 100 mM) or CaCl2 (0.1 to 1.0 mM). The experimental breakthrough curves and retent...

  7. The Effect of Sand Particle Size on the Burrowing Ability of the Beach Mysid Gastrosaccus psammodytes Tattersall

    Science.gov (United States)

    Nel, R.; McLachlan, A.; Winter, D.

    1999-05-01

    Laboratory studies on the burrowing rates of the mysid shrimp, Gastrosaccus psammodytes , in a series of well-sorted sediments, determined whether (1) burial times were dependent on grain size and (2) if natural population distribution may be influenced by grain size on beaches. Burial times were tested in nine well-sorted sediments with grain size ranging from 90 to 2000μm. Large individuals (i.e. gravid females) were used. G. psammodytes burrowed fastest in 125-1000μm sand with mean burial times less than 1·6s. Burial time increased to approximately 2s in 90-125μm sand. G. psammodytes could not burrow in grain sizes coarser than 1000μm. G. psammodytes has been reported to occur on beaches with grain sizes ranging from 90 to 500μm but are uncommon on beaches with coarser sand. It appears that population distribution may be influenced by grain size that is probably not related to the animals' burial time ability, but rather their inability to burrow completely into coarse sand. Indirectly, grain size may also influence the morphodynamic state of a beach and therefore food availability since coarse-grained beaches tend to be reflective with little surf production.

  8. Effect of metal oxides on the reactivity of persulfate/Fe(II) in the remediation of diesel-contaminated soil and sand.

    Science.gov (United States)

    Do, Si-Hyun; Kwon, Yong-Jae; Kong, Sung-Ho

    2010-10-15

    The effect of metal oxides on the ability of persulfate (PS) with Fe(II) to remediate diesel-contaminated soil was investigated. In both natural soil and purchased sand, the highest diesel degradation occurred at pH 3 and the optimum molar ratio of PS/Fe(II) was 100:1 (i.e. 500 mM PS to 5 mM Fe(II)). Moreover, adding Fe(II) increased PS reactivity more in soil than it did in sand, indicating the involvement of metal oxides in the soil matrix. Evaluating the effects of metal oxides (i.e. goethite, hematite, magnetite, and manganese oxide) on the reactivity of PS with/without Fe(II) in a system containing diesel-contaminated sand revealed that manganese oxide increased PS activity the most and that the highest diesel degradation by PS occurred when both manganese oxide and Fe(II) were used as activators. XRD did not show the transformation of manganese oxide in the presence of Fe(II). SEM-EDS showed the association of Fe(II) on the surface of manganese oxide, and ICP analysis revealed that almost all the added Fe(II) adsorbed to manganese oxide but almost none adsorbed to iron oxides under acidic conditions. Therefore, the high reactivity of PS could be due to the high density of Fe(II) over the surface of manganese oxide. 2010 Elsevier B.V. All rights reserved.

  9. Obesity, insulin resistance and diabetes in the sand rat exposed to a hypercaloric diet; possible protective effect for IL1-β.

    Science.gov (United States)

    Khalkhal, Ali; Haddar, Aomar; Semiane, Nesrine; Mallek, Aicha; Abdelmalek, Abdelouadoud; Castex, Françoise; Gross, René; Dahmani, Yasmina

    2012-04-01

    It is well established that, upon changing their natural desert low caloric (succulent halophilic plants) to a regular laboratory high caloric diet, sand rats undergo various phenotypic changes depending on their genetic background and including obesity and various degrees of insulin resistance. Our aim was to investigate the acute effects of Interleukin-1β (IL-1β) and Interferon-γ (IFN-γ) on glucose-induced insulin secretion in normal lean sand rats maintained on their natural diet and in obese insulin resistant normoglycemic or type 2 diabetic animals after a 9-month high caloric diet. Animals were fed either a low or a high caloric diet; after 9 months, pancreatic islets were isolated and incubated in the presence of increasing cytokine concentrations. At the end of the high-energy diet, animals were all over-weight, and probably due to a different genetic background, they displayed either insulin resistance, hyperinsulinemia and normoglycemia or a marked type-2 diabetic state. Pancreatic islets from obese insulin resistant normoglycemic animals were much more sensitive and responsive to IL-1β when compared to lean controls. The cytokine was inefficient in diabetic islets. In conclusion, the markedly increased insulinotropic effect of IL-1β in obese diabetes-resistant sand rat could participate and be involved in pancreatic β-cell hyperactivity that compensates for insulin resistance and thereby prevent the development of type 2 diabetes in these animals.

  10. The Karakum and Kyzylkum sand seas dynamics; mapping and palaeoclimatic interpretations

    Science.gov (United States)

    Maman, Shimrit; Blumberg, Dan G.; Tsoar, Haim; Porat, Naomi

    2015-04-01

    Sand seas are large basins in deserts that are mantled by wind-swept sand and that exhibit varying degrees of vegetation cover. Wilson (1973) was the first to globally map and classify sand seas. Beyond Wilson's maps, however, little research has been published regarding the Karakum and Kyzylkum sand seas of Central Asia. Wilson's maps delineate active ergs from inactive ergs based solely on precipitation. His assumption of annual average rainfall as a factor determining mobility vs. stability of sand seas is too simplistic and does not take into consideration other factors such as biogenic soil crusts and wind power, both of which are known to have major effects on the dynamics of sand dunes. Literature related to mapping and classifying the Central Asian ergs by remote sensing or sand sea classification state (stable/active) is lacking. Moreover, the palaeoclimatic significance of dunes in Central Asia is difficult to assess, as there has been few studies of dune stratigraphy and numerical ages are lacking. Optically stimulated luminescence (OSL) is a firm optical dating method that is used to determine the elapsed time since quartz grains were last exposed to sunlight, thus, their burial. Yet, absolute ages indicating mobilization and stabilization of these sands, are still inadequately known and are here under discussion. The broad concern of this research was to determine the dynamics of the Central Asian sand seas and study the palaeoclimatic changes that brought to their stabilization. As there are no reliable maps or aeolian discussion of these sands, establishment of a digital data base was initially conducted, focusing on identifying and mapping these sand seas. The vast area and inaccessibility make traditional mapping methods virtually impossible. A variety of space-borne imagery both optical and radar, with varying spectral and spatial resolutions was used. These images provided the basis for mapping sand distribution, dune forms, and vegetation cover

  11. [Effects of sand-covering on apple trees transpiration and fruit quality in dry land orchards of Longdong, Gansu].

    Science.gov (United States)

    Zhang, Kun; Yin, Xiao-ning; Liu, Xiao-yong; Wang, Fa-lin

    2010-11-01

    Aiming at the seasonal drought in the dry land orchards of Longdong, Gansu Province, a sand-covering experiment was conducted with 15-year-old Nagafu No. 2 apple trees, with the soil water content, temperature, stem sap flow velocity, leaf stomatal conductance, and fruit quality measured. In the orchard covered with 5-cm-thick riversand, the increment of soil temperature in February-April was lower than 1 degrees C, while in June-July, it was 2.44 degrees C and 2.61 degrees C on sunny and cloudy days, respectively. The soil water content was over 60% of field capacity throughout the growing season. On sunny days with high soil water content (H season), the stem sap flow curve presented a wide peak. Under sand- covering, the sap flow started 0.6 h earlier, and the maximum sap flow velocity was 25.5% higher than the control. On cloudy days of H season, the maximum sap flow velocity was 165.6% higher than the control. On sunny days with low soil water content (L season), the sap flow curve had a single peak, and under sand covering, the sap flow started 0.5-1 h earlier than the control on sunny days. The maximum sap flow velocity was 794 g x h(-1). On cloudy days of L season, the sap flow started 1 h earlier, and the maximum sap flow velocity was 311.0% higher than the control. The evaporation of the control was 156.0% higher than that of sand-covering from March to July, suggesting that excessive ground water evaporation was the main reason to cause soil drought. Under sand-covering, single fruit mass was improved obviously whereas fruit firmness was reduced slightly, and soluble solids, vitamin C, total sugar, and organic acid contents were somewhat promoted.

  12. D-amphetamine and antipsychotic drug effects on latent inhibition in mice lacking dopamine D2 receptors.

    Science.gov (United States)

    Bay-Richter, C; O'Callaghan, M J; Mathur, N; O'Tuathaigh, C M P; Heery, D M; Fone, K C F; Waddington, J L; Moran, P M

    2013-07-01

    Drugs that induce psychosis, such as D-amphetamine (AMP), and those that alleviate it, such as antipsychotics, are suggested to exert behavioral effects via dopamine receptor D2 (D2). All antipsychotic drugs are D2 antagonists, but D2 antagonism underlies the severe and debilitating side effects of these drugs; it is therefore important to know whether D2 is necessary for their behavioral effects. Using D2-null mice (Drd2-/-), we first investigated whether D2 is required for AMP disruption of latent inhibition (LI). LI is a process of learning to ignore irrelevant stimuli. Disruption of LI by AMP models impaired attention and abnormal salience allocation consequent to dysregulated dopamine relevant to schizophrenia. AMP disruption of LI was seen in both wild-type (WT) and Drd2-/-. This was in contrast to AMP-induced locomotor hyperactivity, which was reduced in Drd2-/-. AMP disruption of LI was attenuated in mice lacking dopamine receptor D1 (Drd1-/-), suggesting that D1 may play a role in AMP disruption of LI. Further supporting this possibility, we found that D1 antagonist SKF83566 attenuated AMP disruption of LI in WT. Remarkably, both haloperidol and clozapine attenuated AMP disruption of LI in Drd2-/-. This demonstrates that antipsychotic drugs can attenuate AMP disruption of learning to ignore irrelevant stimuli in the absence of D2 receptors. Data suggest that D2 is not essential either for AMP to disrupt or for antipsychotic drugs to reverse AMP disruption of learning to ignore irrelevant stimuli and further that D1 merits investigation in the mediation of AMP disruption of these processes.

  13. Mineral processing of heavy mineral sands from Malawi and Malaysia

    OpenAIRE

    Mitchell, C J

    1992-01-01

    Processing of heavy mineral sands involves many techniques including gravity, magnetic and electrostatic separation. As part of a laboratory programme to develop effective mineral processing techniques, two mineral sands from Malawi and Malaysia were processed using the standard techniques, with emphasis placed on the Carpco electrostatic separator. These sands were initially characterised mineralogically by scanning electron microscopy (SEM), electron microprobe analysis (EPMA...

  14. Choosing an optimum sand control method

    Directory of Open Access Journals (Sweden)

    Ehsan Khamehchi

    2015-06-01

    Full Text Available Formation sand control is always one of the main concerns of production engineers. There are some different methods to prevent sand production. Choosing a method for preventing formation sand production depends on different reservoir parameters and politic and economic conditions. Sometimes, economic and politic conditions are more effective to choose an optimum than reservoir parameters. Often, simultaneous investigation of politic and economic conditions with reservoir parameters has different results with what is expected. So, choosing the best sand control method is the result of thorough study. Global oil price, duration of sand control project and costs of necessary equipment for each method as economic and politic conditions and well productivity index as reservoir parameter are the main parameters studied in this paper.

  15. Simulation of aeolian sand saltation with rotational motion

    Science.gov (United States)

    Huang, Ning; Wang, Cong; Pan, Xiying

    2010-11-01

    In this work, we propose a theoretical model based on the distribution functions of initial liftoff velocity and angular velocity of sand grains to describe a sand saltation process in which both wind field-sand grain coupling and the Magnus force experienced by saltating sand grains have been incorporated. The computation results showed that the Magnus force had significant effects on sand grain saltation. In particular, when the Magnus force was incorporated, the calculated sand transport fluxes and sand transport rate per unit width were closer to the experimental value than when this force was excluded. The sand transport flux is enhanced because the Magnus force owing to particle rotation causes the particles to have higher and longer trajectories, so the particles can get more speed and energy from the wind, which leads to a larger sand transport flux. In addition, it was found that when taking the Magnus force into account, the probability density of the impact velocity and angular velocity of saltating sand grains followed an exponential distribution and a unimodal asymmetric distribution, respectively. Moreover, the sand energy flux increased with the height above the sand surface until the energy flux reached its maximum and then decreased. Furthermore, the energy flux near the ground surface decreased as the grain diameter increased, but beyond a specific height the energy flux increased with the grain diameter. Finally, for the same sand grain diameter, the energy flux increased with the friction velocity.

  16. Postzygotic isolation involves strong mitochondrial and sex-specific effects in Tigriopus californicus, a species lacking heteromorphic sex chromosomes.

    Science.gov (United States)

    Foley, B R; Rose, C G; Rundle, D E; Leong, W; Edmands, S

    2013-11-01

    Detailed studies of the genetics of speciation have focused on a few model systems, particularly Drosophila. The copepod Tigriopus californicus offers an alternative that differs from standard animal models in that it lacks heteromorphic chromosomes (instead, sex determination is polygenic) and has reduced opportunities for sexual conflict, because females mate only once. Quantitative trait loci (QTL) mapping was conducted on reciprocal F2 hybrids between two strongly differentiated populations, using a saturated linkage map spanning all 12 autosomes and the mitochondrion. By comparing sexes, a possible sex ratio distorter was found but no sex chromosomes. Although studies of standard models often find an excess of hybrid male sterility factors, we found no QTL for sterility and multiple QTL for hybrid viability (indicated by non-Mendelian adult ratios) and other characters. Viability problems were found to be stronger in males, but the usual explanations for weaker hybrid males (sex chromosomes, sensitivity of spermatogenesis, sexual selection) cannot fully account for these male viability problems. Instead, higher metabolic rates may amplify deleterious effects in males. Although many studies of standard speciation models find the strongest genetic incompatibilities to be nuclear-nuclear (specifically X chromosome-autosome), we found the strongest deleterious interaction in this system was mito-nuclear. Consistent with the snowball theory of incompatibility accumulation, we found that trigenic interactions in this highly divergent cross were substantially more frequent (>6×) than digenic interactions. This alternative system thus allows important comparisons to studies of the genetics of reproductive isolation in more standard model systems.

  17. Sands cykliske styrke

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    1992-01-01

    Sands cykliske styrke kan beskrives ved Cyclic Liquefaction, Mobilisering, Stabilization og Instant Stabilization. I artiklen beskrives hvorfor Stabilization og Instant Stabilization ikke observeres, når sands udrænede styrke undersøges i triaxial celler, der anvender prøver med dobbelt prøvehøjde....

  18. Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Bødker, Lars Bødker

    The Soil Mechanics Laboratory has started performing tests with a new sand, Baskarp No 15. Baskarp No 15 is a graded sand from Sweden. The shapes of the largest grains are round, while the small grains have sharp edges. The main part of of Baskarp No 15 is quarts, but it also contains feldspar...

  19. Effect of particle size on the measurement of the apparent contact angle in sand of varying wettability under air-dried conditions

    Directory of Open Access Journals (Sweden)

    Saulick Yunesh

    2016-01-01

    Full Text Available Changes in the wettability of soil are known to affect several processes such as infiltration and the shear strength of soil. In this study, the wettability of a medium to fine sand was chemically modified by using different concentrations of dimethyldichlorosilane (DMDCS. The sessile drop method (SDM was used for the assessment of wettability of hydrophobised Leighton Buzzard Sand (LBS. The results demonstrate that beyond a concentration of 2 g per kg of LBS, the finer fraction had its apparent contact angle (ACA increased up to 115° while the maximum ACA attained by the coarser fractions was 100°. At such high concentration of DMDCS, the effect of trapped air, which is known to increase the ACA, was found to be either small or insignificant. The standard deviations of the ACAs agreed well with past studies. The most important factors contributing to the water-repellent behaviour of chemically synthesised sand were attributed to the characteristics of the particles; these include surface area and particle shape.

  20. Effect of sand and method of mixing on molten salt properties for an open direct absorption solar receiver/storage system

    Science.gov (United States)

    AlQaydi, Muna; Delclos, Thomas; AlMheiri, Saif; Calvet, Nicolas

    2017-06-01

    The concept of CSPonD Demo project is based on a single and open molten salt tank as a thermal solar receiver and storage unit. Therefore, the effect of external environment such as sand and air on the thermophysical properties of nitrate salt (60 wt. % sodium nitrate, 40 wt. % potassium nitrate) has been investigated in this work. Differential Scanning Calorimeter (DSC) was used to determine the melting, solidification temperatures while the thermal stability and mass loss measurements were carried on Thermal Gravimetric Analysis (TGA). Measurements under nitrogen indicate that the adding 2% (w/w) sand has negative impact by increasing the solidification temperature, mass loss percentage and decreasing the stability limit. While the melting temperature was not affected by the sand and by the preparation method. On the other hand, measurement under air showed an increase of the stability limit and decrease of the mass loss percentage. Furthermore, the measurements for the mass loss under air did not reach a stable value, which required further investigation.

  1. Effects of sand burial on biomass, chlorophyll fluores-cence and extracellular polysaccharides of man-made cyanobacterial crusts under experimental conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Soil cyanobacterial crusts occur throughout the world, especially in the semiarid and arid regions. It always encounters sand burial, which is an important feature of mobile sand dunes. A greenhouse study was conducted to determine the effects of sand burial on biomass, chlorophyll fluorescence and extracellular polysaccharides of man-made cyanobacterial crusts in six periods of time (0, 5, 10, 15, 20 and 30 d after burying) and at five depths (0, 0.2, 0.5, 1 and 2cm). The results indicated that with the increase of the burial time and burial depth extracellular polysaccharides content and Fv/Fm decreased correspondingly and there were no significant differences between 20 and 30 burial days under dif-ferent burial depths. The degradation of chlorophyll a content appeared only at 20 and 30 burial days and there was also no significant difference between them under different burial depths. It was also observed a simultaneous decrease of the values of the Fv/Fm and the content of extracellular poly-saccharides happened in the crusted cyanobacterium Microcoleus vaginatus Gom. It may suggest that there exists a relationship between extracellular polysaccharides and recovery of the activity of pho-tosystem II (PS II) after rehydration.

  2. Variable rainfall intensity and tillage effects on runoff, sediment, and carbon losses from a loamy sand under simulated rainfall.

    Science.gov (United States)

    Truman, C C; Strickland, T C; Potter, T L; Franklin, D H; Bosch, D D; Bednarz, C W

    2007-01-01

    The low-carbon, intensively cropped Coastal Plain soils of Georgia are susceptible to runoff, soil loss, and drought. Reduced tillage systems offer the best management tool for sustained row crop production. Understanding runoff, sediment, and chemical losses from conventional and reduced tillage systems is expected to improve if the effect of a variable rainfall intensity storm was quantified. Our objective was to quantify and compare effects of a constant (Ic) intensity pattern and a more realistic, observed, variable (Iv) rainfall intensity pattern on runoff (R), sediment (E), and carbon losses (C) from a Tifton loamy sand cropped to conventional-till (CT) and strip-till (ST) cotton (Gossypium hirsutum L.). Four treatments were evaluated: CT-Ic, CT-Iv, ST-Ic, and ST-Iv, each replicated three times. Field plots (n=12), each 2 by 3 m, were established on each treatment. Each 6-m2 field plot received simulated rainfall at a constant (57 mm h(-1)) or variable rainfall intensity pattern for 70 min (12-run ave.=1402 mL; CV=3%). The Iv pattern represented the most frequent occurring intensity pattern for spring storms in the region. Compared with CT, ST decreased R by 2.5-fold, E by 3.5-fold, and C by 7-fold. Maximum runoff values for Iv events were 1.6-fold higher than those for Ic events and occurred 38 min earlier. Values for Etot and Ctot for Iv events were 19-36% and 1.5-fold higher than corresponding values for Ic events. Values for Emax and Cmax for Iv events were 3-fold and 4-fold higher than corresponding values for Ic events. Carbon enrichment ratios (CER) were or=1.0 for CT plots (except for first 20 min). Maximum CER for CT-Ic, CT-Iv, ST-Ic, and ST-Iv were 2.0, 2.2, 1.0, and 1.2, respectively. Transport of sediment, carbon, and agrichemicals would be better understood if variable rainfall intensity patterns derived from natural rainfall were used in rainfall simulations to evaluate their fate and transport from CT and ST systems.

  3. Lack of inhibitory effects of Lactic acid bacteria on 1,2-dimethylhydrazine-induced colon tumors in rats

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Chong-Bi Li

    2003-01-01

    AIM: A myriad of healthful effects has been attributed to the probiotic lactic acid bacteria, perhaps the most controversial issue remains that of anticancer activity. This study was aimed at investigating the putative anti-cancer effects of lactic acid bacteria strains on the progression of colon tumor in 1,2-dimethylhydrazine (DMH)-treated animals.METHODS: The strain of lactic acid bacteria used in this study was lactic acid bacteria NZ9000 that conformed to the characteristics of plasmid free. Sixty male Wistar rats were given subcutaneous injections of DMH at a dose of 40 mg/kg body wt or saline once a week for 10 weeks. The rats were divided into 6 experimental groups. After the last DMH injection,animals in groups 1 and 4 were gavaged with 1 mi of lactic acid bacteria at a dose of 5×109 per day or vehide until sacrifice at the end of week 22 or week 52. Animals in groups 1-3 were killed at the end of week 22 for histopathological examination.The whole period of experimental observation was 52 weeks.RESULTS: By the end of 22nd week, final average body weights of the rats treated with DMH alone and all animals receiving lactic acid bacteria were significantly decreased compared with the vehicle control (P<0.05). No differences in tumor inridence, multiplicity, dimensions and stage in the colonic mucosa were observed among the groups. At week 52, the survival rate of the rats administered lactic acid bacteria was lower than that of the rats treated with DMH that were fed on control fluids of non-lactococcus lactis. The mean survival time of lactic acid bacteria-treated animals was 39 weeks.CONCLUSION: These results indicate that lactic acid bacteria lacks inhibitory effects on the progression of colon tumor in DMH-treated animals, and does not support the hypothesis that alteration of colonic flora may exert an influence on the progression of colon tumor.

  4. Properties of phosphofructokinase from the mucosa of rat jejunum and their relation to the lack of Pasteur effect.

    Science.gov (United States)

    Tejwani, G A; Ramaiah, A

    1971-11-01

    1. The properties of phosphofructokinase after its slight purification from the mucosa of rat jejunum were studied. 2. The enzyme is inhibited by almost 100% by an excess of ATP (1.6mm), with 0.2mm-fructose 6-phosphate. AMP, ADP, P(i) and NH(4) (+) at 0.2, 0.76, 1.0 and 2mm respectively do not individually prevent the inhibition of phosphofructokinase activity by 1.6mm-ATP with 0.2mm-fructose 6-phosphate to any great extent, but all of them together completely prevent the inhibition of phosphofructokinase by ATP. 3. One of the effects of high concentrations of ATP on the enzyme was to increase enormously the apparent K(m) value for the other substrate fructose 6-phosphate, and this increase is largely counteracted by the presence of AMP, ADP, P(i) and NH(4) (+). At low concentrations of ATP the above effectors individually decrease the concentration of fructose 6-phosphate required for half-maximum velocity and when present together they decrease it further, in a more than additive way. 4. When fructose 6-phosphate is present at a saturating concentration (5mm), 0.3mm-NH(4) (+) increases the maximum velocity of the reaction 3.3-fold; with 0.5mm-fructose 6-phosphate, 4.5mm-NH(4) (+) is required for maximum effect. The other effectors do not change the maximum reaction velocity. 5. The results presented here suggest that NH(4) (+), AMP, ADP and P(i) synergistically decrease the inhibition of phosphofructokinase activity at high concentrations of ATP by decreasing the concentration of fructose 6-phosphate required for half-maximum velocity. Such synergism among the effectors and an observed, low ;energy charge' [(ATP+(1/2)ADP)/(AMP+ADP+ATP)] in conjunction with the possibility of a relatively high NH(4) (+) and fructose 6-phosphate concentration in this tissue, may keep the mucosal phosphofructokinase active and uninhibited by ATP under aerobic conditions, thus explaining the high rate of aerobic glycolysis and the lack of Pasteur effect in this tissue.

  5. Sand Dune Encroachment and Desertification Processes of the Rigboland Sand Sea, Central Iran.

    Science.gov (United States)

    Ahmady-Birgani, Hesam; McQueen, Kenneth G; Moeinaddini, Mazaher; Naseri, Hamidreza

    2017-05-08

    Early studies on sand dune movement and desertification in Iran have not always been convincingly demonstrated because of problems with the field-based measurements. In some areas where various land uses have been engulfed by aeolian sand dunes, desertification is clear, but in other less settled areas, it may not be so obvious. The objective of this study is to demonstrate encroachments of the Rigboland sand sea, central Iran, in its different directions and variable magnitude rates. Determining the rate and direction of the sand sea movements is critical for specifying which lands should be prioritized and quickly protected. The study has trialed a change detection technique which uses a Cross-Tabulation module to compare two available LandsatTM images over the Rigboland sand sea. This indicates that within a ten-year span (from 1988 to 1998) more than 200 ha/yr were added to the Rigboland sand sea, from the alluvial fan landforms in the eastern upstream, outer margins of the Rigboland sand sea. Coupled with GIS techniques, this type of analysis of the remote sensing (RS) images provides an effective tool for the monitoring and prognostication of sand dune movement and sand sea change.

  6. Monitoring the Effects of Oil Sands Process-Affected Water (OSPW) on Thecamoebian Assemblages: An Experimental Approach

    Science.gov (United States)

    Christie, D. G.; McCarthy, F. F.; Penner, T.; MacKinnon, M. M.

    2009-05-01

    Thecamoebian (testate amoeba) assemblages have been shown to respond over short time periods to environmental conditions in aquatic reclamation options under development at oil sands operations in northeastern Alberta. This makes them a useful bio-monitoring tool for assessing reclamation success. Thecamoebian responses to Oil Sands Process Water (OSPW) have been monitored in the field at lacustrine and wetland test sites established by Syncrude Canada Ltd. and Suncor Energy Ltd. These field studies have confirmed that the generation times of testate amoebas is sufficiently rapid to permit the construction of a controlled laboratory experiment to be completed within one year, where controlled exposures of a natural assemblage of thecamoebians to OSPW can be undertaken to better understand the community responses to stressors We intend to culture these protists in the lab and monitor their response to different concentrations of OSPW in a controlled environment. Survival and changes in relative community composition (difflugiids vs. centropyxids) will be used to establish the dilution of OSPW in which thecameobians can survive and examine how a natural assemblage changes over time in response to increased concentrations of OSPW. This will assist in reclamation management in the Oil Sands region of Alberta.

  7. Effects of oil and gas well-drilling fluids on the biomass and community structure of microbiota that colonize sands in running seawater.

    Science.gov (United States)

    Smith, G A; Nickels, J S; Bobbie, R J; Richards, N L; White, D C

    1982-01-01

    Well-drilling fluid and a number of the known components (barite, clay, Aldacide, Surflo, and Dowicide, were tested for effects on the biomass and community structure of the microbiota that colonize marine sands exposed for eight weeks to running ambient seawater. Shading the microbiota from light depressed the microflora without a significant effect on the biomass, while well-drilling fluids layered on the surface or mixed with the sand significantly increased a component of the bacteria and the microfauna as reflected in changes in the fatty acid composition. There were some shading effects from the surface layering of well-drilling fluids as reflected in the fatty acids from the microflora when compared to the sands mixed with well-drilling fluids. Barite had essentially no effect on the biomass or community structure while clays increased nearly all of the biomass indicators for the bacteria as well as the microfauna; the clay overlay mirrors the effect of the drilling fluids. Aldacide shifted the bacterial composition, depressing the proportions of microbes containing the cyclopropane fatty acids and the anaerobic pathways of desaturation. Concentrations of 1 and 15 microgram/L increased the bacterial biomass as reflected in the total lipid (16:0) and extractable lipid phosphate coupled with a decrease in the total microeukaryotes. Surflo increased the biomass and shifted the bacterial community structure at concentrations between 4 and 800 microgram/L. The lowest level also stimulated the microfauna. Dowicide at 100 microgram/L increased the bacteria forming cis-vaccenic acid and the microfauna similar to low concentrations of Surflo.

  8. Diagnosis of the heating effect on the electrical resistivity of Ouargla (Algeria) dunes sand using XRD patterns and FTIR spectra

    Science.gov (United States)

    Mechri, Mohammed Laïd; Chihi, Smaïl; Mahdadi, Naouia; Beddiaf, Samiha

    2017-01-01

    XRD patterns and FTIR spectra have shown that dunes sand of Ouargla's region, in its natural state, is formed of a high percentage of quartz, gypsum and very low percentage of kaolinite and hematite, in addition to some organic compounds. The electrical resistivity of the natural sand has been measured, it was 6 × 1014 Ω cm. Six samples of the sand were heated separately at 200, 400, 600, 800, 1000 and 1200 °C. The XRD patterns and FTIR spectra of these samples were carried out. On the other hand, the electrical resistivities of these samples have been measured. The change of the electrical resistivity with heat shows a nonlinear behavior. The heated sample of sand at 200 °C has lost some water. Most of the gypsum in the 200 °C heated sample has transformed into anhydrite, and the rest has transformed into bassanite, and its electrical resistivity has fallen down to 3.5 × 1014 Ω cm. By heating at 400 °C, the gypsum has lost all its water and it has transformed entirely to anhydrite, and its electrical resistivity became 6.75 × 1012 Ω cm, it has the lowest measured resistivity. At 600 °C and 800 °C, in addition to anhydrite, the kaolinite transformed to meta-kaolin due to the continuous breaking of OH bond and formation of water vapor, and the electrical resistivity increased to (1.5-1.9) × 1014 Ω cm. Heating at 1000 °C leads to the initiation of the interaction between anhydrite and quartz, the wollastonite appears, and the meta-kaolin transforms to aluminum-silicon and cristobalite. The wollastonite is a good electrical insulator. It raises the electrical resistivity of sand to 2.6 × 1014 Ω cm. The heating at 1200 °C makes all anhydrite to interact with quartz due to the increasing of volume of wollastonite, the anhydrite disappears completely, the quartz transforms into cristobalite. The cristobalite increases due to the dissociation of aluminium-silicon into mullite and cristobalite, as well as the transformation of quartz into cristobalite at

  9. Sand and Gravel Deposits

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset is a statewide polygon coverage of sand, gravel, and stone resources. This database includes the best data available from the VT Agency of Natural...

  10. Sand and Gravel Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

  11. Adsorption of dyes on Sahara desert sand.

    Science.gov (United States)

    Varlikli, Canan; Bekiari, Vlasoula; Kus, Mahmut; Boduroglu, Numan; Oner, Ilker; Lianos, Panagiotis; Lyberatos, Gerasimos; Icli, Siddik

    2009-10-15

    Sahara desert sand (SaDeS) was employed as a mineral sorbent for retaining organic dyes from aqueous solutions. Natural sand has demonstrated a strong affinity for organic dyes but significantly lost its adsorption capacity when it was washed with water. Therefore, characterization of both natural and water washed sand was performed by XRD, BET, SEM and FTIR techniques. It was found that water-soluble kyanite, which is detected in natural sand, is the dominant factor affecting adsorbance of cationic dyes. The sand adsorbs over 75% of cationic dyes but less than 21% for anionic ones. Among the dyes studied, Methylene Blue (MB) demonstrated the strongest affinity for Sahara desert sand (Q(e)=11.98 mg/g, for initial dye solution concentration 3.5 x 10(-5)mol/L). The effects of initial dye concentration, the amount of the adsorbent, the temperature and the pH of the solution on adsorption capacity were tested by using Methylene Blue as model dye. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied. It was concluded that adsorption of Methylene Blue on Sahara desert sand followed pseudo-second order kinetics. Gibbs free energy, enthalpy change and entropy change were calculated and found -6411 J/mol, -30360 J/mol and -76.58 J/mol K, respectively. These values indicate that the adsorption is an exothermic process and has a spontaneous nature at low temperatures.

  12. Sand Flies and Their Control Methods.

    Science.gov (United States)

    Çetin, Hüseyin; Özbel, Yusuf

    2017-06-01

    The main aim of managing arthropod vectors that carry the disease agents is interrupting the infection cycle. Therefore, the management of the disease implies that all precautions related to all elements (i.e., human, arthropod vector, and reservoir) in the infection cycle need to be taken. There are important points that need to be considered while dealing with sand flies (Diptera: Psychodidae: Phlebotominae), which in many regions worldwide, particularly in tropical and subtropical areas, are vectors of diseases such as leishmaniasis and sand fly fever and are the arthropods of the infection cycle. Because the larval control of the sand flies is very difficult and almost impossible, the management is mainly conducted for the adults. The most effective strategy for reducing both sand fly fever and leishmaniasis is managing sand flies, particularly in areas where humans are located. In this review, the morphology, biology, and taxonomy of sand flies; the integrated fighting and management methods such as insecticide-impregnated bed nets and use of curtains, zooprophylaxis, indoor and outdoor residual applications, larvicides, repellents, and insecticide-impregnated dog collars; and data regarding many issues such as insecticide resistance in sand flies have been emphasized on in the review.

  13. Vestled - Hvide Sande

    DEFF Research Database (Denmark)

    Juel-Christiansen, Carsten; Hesselbjerg, Marianne; Schønherr, Torben

    2009-01-01

    Værket Vestled i Hvide Sande præsenteret i sammenhæng af 1000 nutidige landskabsarkitektoniske arbejder fra hele verden, hvor hvert værk vises på én side......Værket Vestled i Hvide Sande præsenteret i sammenhæng af 1000 nutidige landskabsarkitektoniske arbejder fra hele verden, hvor hvert værk vises på én side...

  14. Effect of erbium-doped: yttrium, aluminium and garnet laser irradiation on the surface microstructure and roughness of sand-blasted, large grit, acid-etched implants

    OpenAIRE

    2011-01-01

    Purpose The present study was performed to evaluate the effect of erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser irradiation on sand-blasted, large grit, acid-etched (SLA) implant surface microstructure according to varying energy levels and application times of the laser. Methods The implant surface was irradiated by the Er:YAG laser under combined conditions of 100, 140, or 180 mJ/pulse and an application time of 1 minute, 1.5 minutes, or 2 minutes. Scanning electron microscopy ...

  15. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  16. Measurement of elastic modulus and evaluation of viscoelasticity of foundry green sand

    Directory of Open Access Journals (Sweden)

    Qingchun XIANG

    2004-08-01

    Full Text Available Elastic modulus is an important physical parameter of molding sand; it is closely connected with molding sand's properties. Based on theories of rheology and molding sand microdeformation, elastic modulus of molding sand was measured and investigated using the intelligent molding sand multi-property tester developed by ourselves. The measuring principle was introduced. Effects of bentonite percentage and compactibility of the molding sand were experimentally studied. Furthermore, the essential viscoelastic nature of green sand was analyzed. It is considered that viscoelastic deformation of molding sand consists mainly of that of Kelvin Body of clay membrane, and elastic modulus of molding sand depends mainly on that of Kelvin Body which is the elastic component of clay membrane between sands. Elastic modulus can be adopted as one of the property parameters, and can be employed to evaluate viscoelastic properties of molding sand.

  17. Measurement of elastic modulus and evaluation of viscoelasticity of foundry green sand

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Elastic modulus is an important physical parameter of molding sand; it is closely connected with molding sand's properties. Based on theories of rheology and molding sand microdeformation, elastic modulus of molding sand was measured and investigated using the intelligent molding sand multi-property tester developed by ourselves. The measuring principle was introduced. Effects of bentonite percentage and compactibility of the molding sand were experimentally studied. Furthermore, the essential viscoelastic nature of green sand was analyzed. It is considered that viscoelastic deformation of molding sand consists mainly of that of Kelvin Body of clay membrane, and elastic modulus of molding sand depends mainly on that of Kelvin Body which is the elastic component of clay membrane between sands. Elastic modulus can be adopted as one of the property parameters, and can be employed to evaluate the viscoelastic properties of molding sand.

  18. Experimental effect of feeding on Ricinus communis and Bougainvillea glabra on the development of the sand fly Phlebotomus papatasi (Diptera: Psychodidae) from Egypt.

    Science.gov (United States)

    Kaldas, Rania M; El Shafey, Azza S; Shehata, Magdi G; Samy, Abdallah M; Villinski, Jeffrey T

    2014-04-01

    Plants are promising sources of agents useful for the control of vectors of human diseases including leishmaniasis. The effect of Ricinus communis (Euphorbiaceae) and Bougainvillea glabra (Nyctaginaceae), on transmission of leishmaniasis was investigated using them as diets for Phlebotomus papatasi to monitor their effect on life-history traits. P. papatasi were allowed to feed separately on both plants then offered a blood-meal. Fed-females were observed daily for egg-laying and subsequent developmental stages. P. papatasi was able to feed on B. glabra (29.41% females and 46.30% males) and R. communis (5.80% females and 10.43% males). 34.28% of females died within 24-48 hours post-feeding on R. communis, whereas, it was 16.5% in females fed on B. glabra. Overall fecundity of surviving females was reduced compared to controls, reared on standard laboratory diet; however there was no effect on the sex ratio of progeny. Female P. papatasi in the control group had significantly longer life span compared to plant-fed group. Feeding on these plants not only decreased sand fly survival rates but incurred negative effects on fecundity. Findings indicate that planting high densities of R. communis and B. glabra in sand flies-endemic areas will reduce population sizes and reduce the risk of Leishmania major infections.

  19. 海砂对混凝土耐久性的影响及其淡化处理%Effect of sea sand on concrete durability and the desalination

    Institute of Scientific and Technical Information of China (English)

    贺烽; 韩继先

    2015-01-01

    近年来,随着河砂开采的限制和资源的匮乏,海砂在沿海地区建筑行业中的使用越来越普遍.介绍了我国的海砂资源情况和海砂性能特征,并分析了海砂中盐类尤其是氯盐和杂质对混凝土耐久性能的影响.海砂通过淡化处理,可以很好地去除其中有害的盐类和杂质,从而可确保淡化后的海砂在建筑工程中的安全可靠应用.%In recent years, with the restricted mining and resource-poor of river sand, the utilization of sea sand in construction indus?try of coastal area is more and more common. China sea sand resource and performance characteristics are introduced, and the effects of chlorate and impurities in sea sand on concrete durability are analysed. By desalinating the harmful chlorate and impurities in sea sand can be moved effectively, which guarantees safe and reliable application of desalted sea sand in construction engineering.

  20. Analysis of Wind-blown Sand Movement over Transverse Dunes

    Science.gov (United States)

    Jiang, Hong; Huang, Ning; Zhu, Yuanjian

    2014-12-01

    Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification.

  1. Laboratory evaluation of selected tar sand asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Button, J.W.; Epps, J.A.; Gallaway, B.M.

    1980-12-01

    Three tar sand asphalts of similar grades prepared from one syncrude by three different refining methods were characterized by tests commonly used to specify paving asphalts together with certain special tests. Asphalt-aggregate mixtures were prepared using these asphalts and tested in the laboratory to determine strength stiffness stability, tensile properties, temperature effects and water susceptibility. Comparison of the tar sand asphalt properties to conventional petroleum asphalt properties reveal no striking differences.

  2. Ejecta velocity distribution of impact craters formed on quartz sand: Effect of projectile density on crater scaling law

    Science.gov (United States)

    Tsujido, Sayaka; Arakawa, Masahiko; Suzuki, Ayako I.; Yasui, Minami

    2015-12-01

    In order to clarify the effects of projectile density on ejecta velocity distributions for a granular target, impact cratering experiments on a quartz sand target were conducted by using eight types of projectiles with different densities ranging from 11 g cm-3 to 1.1 g cm-3, which were launched at about 200 m s-1 from a vertical gas gun at Kobe University. The scaling law of crater size, the ejection angle of ejecta grains, and the angle of the ejecta curtain were also investigated. The ejecta velocity distribution obtained from each projectile was well described by the π-scaling theory of v0/√{gR} =k2(x0/R)-1/μ, where v0, g, R and x0 are the ejection velocity, gravitational acceleration, crater radius and ejection position, respectively, and k2 and μ are constants mostly depending on target material properties (Housen, K.R., Holsapple, K.A. [2011]. Icarus 211, 856-875). The value of k2 was found to be almost constant at 0.7 for all projectiles except for the nylon projectile, while μ increased with the projectile density, from 0.43 for the low-density projectile to 0.6-0.7 for the high-density projectile. On the other hand, the π-scaling theory for crater size gave a μ value of 0.57, which was close to the average of the μ values obtained from ejecta velocity distributions. The ejection angle, θ, of each grain decreased slightly with distance, from higher than 45° near the impact point to 30-40° at 0.6 R. The ejecta curtain angle is controlled by the two elementary processes of ejecta velocity distribution and ejection angle; it gradually increased from 52° to 63° with the increase of the projectile density. The comparison of our experimental results with the theoretical model of the crater excavation flow known as the Z-model revealed that the relationship between μ and θ obtained by our experiments could not be described by the Z-model (Maxwell, D.E. [1977]. In: Roddy, D.J., Pepin, R.O., Merrill, R.B. (Eds.), Impact and Explosion Cratering

  3. Bio-physicochemical effects of gamma irradiation treatment for naphthenic acids in oil sands fluid fine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Boudens, Ryan; Reid, Thomas; VanMensel, Danielle; Sabari Prakasanm, M.R. [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON (Canada); Ciborowski, Jan J.H. [Biological Sciences, University of Windsor, Windsor, ON (Canada); Weisener, Christopher G., E-mail: weisener@uwindsor.ca [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON (Canada)

    2016-01-01

    Naphthenic acids (NAs) are persistent compounds that are components of most petroleum, including those found in the Athabasca oil sands. Their presence in freshly processed tailings is of significant environmental concern due to their toxicity to aquatic organisms. Gamma irradiation (GI) was used to reduce the toxicity and concentration of NAs in oil sands process water (OSPW) and fluid fine tailings (FFT). This investigation systematically studied the impact of GI on the biogeochemical development and progressive reduction of toxicity using laboratory incubations of fresh and aged tailings under anoxic and oxic conditions. GI reduced NA concentrations in OSPW by up to 97% in OSPW and in FFT by 85%. The GI-treated FFT exhibited increased rates of biogeochemical change, dependent on the age of the tailings source. Dissolved oxygen (DO) flux was enhanced in GI-treated FFT from fresh and aged source materials, whereas hydrogen sulfide (HS{sup −}) flux was stimulated only in the fresh FFT. Acute toxicity to Vibrio fischeri was immediately reduced following GI treatment of fresh OSPW. GI treatment followed by 4-week incubation reduced toxicity of aged OSPW to V. fischeri. - Highlights: • Gamma irradiation substantially reduced concentrations of ecotoxic naphthenic acids • Acute toxicity was reduced in gamma irradiated process water • Gamma irradiated tailings exhibited increased rates of microbial respiration.

  4. Effect of liquid distribution on gas-water phase mass transfer in an unsaturated sand during infiltration

    Science.gov (United States)

    Imhoff, Paul T.; Jaffé, Peter R.

    1994-09-01

    Gas-water phase mass transfer was examined in a homogeneous sand with both the gas and water phase mobile: water was infiltrated from the top of the sand column while benzene-laden air flowed upward from the bottom. Mass-transfer limitations for this situation may be important for applications of bioventing, where water and nutrients are added at the ground surface simultaneously with induced air movement to carry oxygen and volatile organics to microbial populations. Gas- and water-phase samples indicate that gas-water phase mass transfer was sufficiently fast that equilibrium between gas and water phases was achieved at all sampling locations within the porous medium. Lower-bound estimates for the gas-water mass-transfer rate coefficient show that mass transfer was at least 10-40 times larger than predictions made from an empirical model developed for gas-water phase mass transfer in an identical porous medium. A water-phase tracer test demonstrates that water flow was much more uniform in this study than in those earlier experiments, which is a likely explanation for the differing rates of gas-water phase mass transfer. It is hypothesized that the liquid distribution in previous laboratory experiments was less uniform because of preferential flow paths due to wetting front instabilities. Gas-water phase mass-transfer rate coefficients reported in this investigation are for an ideal situation of uniform water infiltration: mass-transfer rates in field soils are expected to be significantly smaller.

  5. [Effect of sand-stabilization engineering on soil humus and components by analysis by several spectroscopy methods].

    Science.gov (United States)

    Zhang, Yu-lan; Sun, Cai-xia; Duan, Zheng-hu; Chen, Li-jun; Wu, Zhi-jie; Chen, Xiao-hong; Zhang, Ai-ming; Liu, Xing-bin; Wang, Jun-yu

    2010-01-01

    After the potassium bichromate-strong sulfuric acid hot process, the ultraviolet spectrophotometer was used on the contrast with the traditional titrimetric method to analyze soil (51 years, 43 year, 32 year, 20 year vegetations restores in the Tenggeli sand) humus and the humus components content. At the same time, the infrared spectrum was used to discuss their structure change during restoring process. The result indicated that using the visible spectroscopy method for the determination of the humus and the humus component is feasible. The spectroscopy method determination of organic matter is better (coefficient of variation at most is 7.26%) than the traditional titrimetric method, as it is accurate, fast and simple, and favors large quantities. The result indicated that humus content presents increasing tendency along with restoring ages. Change is big in early restore time, and tends to be stable in the later period. Infrared spectrum shape is similar, but the characteristic peak intensity has obvious difference. Compared with the wind-drift sand, little molecule saccharides decrease and aryl-groups increase.

  6. Study of the anti-sand sucker rod pump

    Science.gov (United States)

    Wei, Hangxin; Lv, Bingxin; Xi, Wenkui; Yi, Peng

    2017-06-01

    In order to solve the problem of sand stuck in the sucker rod pump, an anti-sand sucker rod pump is designed. The anti-sand sucker rod pump includes the conventional sucker rod pump and the swirl flow device. The sand particles can be separated from the oil in the swirl flow device, so the plunger of the sucker rod pump cannot be stuck. The motion equation of the sand particles in oil is deduced. The virtual model of the swirl flow device is built in GAMBIT software. And simulation of solid-liquid two phase flow is simulated in software FLUENT. The simulation results show that the swirl flow device can realize the sand particles separation from the oil completely. So the pump can have the effect of anti-sands.

  7. Effect of night time-intervals, height of traps and lunar phases on sand fly collection in a highly endemic area for canine leishmaniasis.

    Science.gov (United States)

    Gaglio, Gabriella; Brianti, Emanuele; Napoli, Ettore; Falsone, Luigi; Dantas-Torres, Filipe; Tarallo, Viviana D; Otranto, Domenico; Giannetto, Salvatore

    2014-05-01

    The activity of phlebotomine sand flies was monitored in a sub-urban area of Sicily in order to acquire data on seasonality and to elucidate the effect of the night time-intervals, height of traps from ground and lunar phases on the abundance of the capture. The study was conducted in the farm of the University of Messina (Italy). Light traps were placed as in the following: biweekly, from dusk to dawn, and from May to November; for three consecutive nights from 18:00 to 6:00, with the net bag being changed every 2h; for 30 days, at different heights from 18:00 to 6:00. A total of five species (i.e., Phlebotomus perniciosus, Phlebotomus neglectus, Phlebotomus sergenti, Phlebotomus perfiliewi, and Sergentomyia minuta), three of which are proven vectors of Leishmania infantum, were captured. The most abundant species was P. perniciosus (73.3%) followed by S. minuta (23.3%). The highest number of phlebotomine sand flies was collected in August and September with a peak of collection recorded in the evening (i.e., from 20:01 to 22.00). The number of phlebotomine sand flies collected at 50cm above the ground was significantly higher (P=0.041) than that captured at 150cm. Results of this study shed light on the ecology of main phlebotomine species in the Mediterranean area, and on the influence of some factors, such as time and height of traps, on the light trap capture efficiency.

  8. Lack of chart reminder effectiveness on family medicine resident JNC-VI and NCEP III guideline knowledge and attitudes

    Directory of Open Access Journals (Sweden)

    Upshur Ross EG

    2004-07-01

    Full Text Available Abstract Background The literature demonstrates that medical residents and practicing physicians have an attitudinal-behavioral discordance concerning their positive attitudes towards clinical practice guidelines (CPG, and the implementation of these guidelines into clinical practice patterns. Methods A pilot study was performed to determine if change in a previously identified CPG compliance factor (accessibility would produce a significant increase in family medicine resident knowledge and attitude toward the guidelines. The primary study intervention involved placing a summary of the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI and the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP III CPGs in all patient (>18 yr. charts for a period of three months. The JNC VI and NCEP III CPGs were also distributed to each Wayne State family medicine resident, and a copy of each CPG was placed in the preceptor's area of the involved clinics. Identical pre- and post- intervention questionnaires were administered to all residents concerning CPG knowledge and attitude. Results Post-intervention analysis failed to demonstrate a significant difference in CPG knowledge. A stastically significant post-intervention difference was found in only on attitude question. The barriers to CPG compliance were identified as 1 lack of CPG instruction; 2 lack of critical appraisal ability; 3 insufficient time; 4 lack of CPG accessibility; and 5 lack of faculty modeling. Conclusion This study demonstrated no significant post intervention changes in CPG knowledge, and only one question that reflected attitude change. Wider resident access to dedicated clinic time, increased faculty modeling, and the implementation of an electronic record/reminder system that uses a team-based approach are compliance factors that

  9. Evaluation of the Synergistic Effect of Erosion-Corrosion on AISI 4330 Steel in Saline-Sand Multiphase Flow by Electrochemical and Gravimetric Techniques

    Directory of Open Access Journals (Sweden)

    Dario Yesid Peña Ballesteros

    2016-01-01

    Full Text Available The synergistic effects of fluid flow, sand particles, and solution pH on erosion-corrosion of AISI 4330 steel alloy in saline-sand medium were studied through a rotating cylinder electrode (RCE system by weight-loss and electrochemical measurements. The worn surface was analyzed by X-ray diffraction (XRD and scanning electron microscopy (SEM. Results show that, under all the test conditions assessed, the passivity of the steel alloy could not be maintained; as a result, an activation mechanism dominates the corrosion process of steel alloy. Furthermore, the potentiodynamic curves show that, with the increasing of the electrode flow rate and particle size, the anodic current density increased, which is due to deterioration of the electrode by the impacting slurry. Although the increase of particle size affects the anodic current density, the effect of particle size does not cause a significant change in the polarization behavior of the steel electrode. The electrochemical impedance and potentiodynamic curves suggest that erosion-corrosion phenomenon of the ASISI 4330 steel is under mixed control of mass transport and charge transfer. The inductive loops formed in the impedance plots are representative of an increase in roughness of the electrode caused by the particles impacting at the surface. The change in the passivity of the steel alloy as the pH is altered plays an important role in the corrosion rate.

  10. Effect of bulk microstructure of commercially pure titanium on surface characteristics and fatigue properties after surface modification by sand blasting and acid-etching.

    Science.gov (United States)

    Medvedev, A E; Ng, H P; Lapovok, R; Estrin, Y; Lowe, T C; Anumalasetty, V N

    2016-04-01

    Surface modification techniques are widely used to enhance the biological response to the implant materials. These techniques generally create a roughened surface, effectively increasing the surface area thus promoting cell adhesion. However, a negative side effect is a higher susceptibility of a roughened surface to failure due to the presence of multiple stress concentrators. The purpose of the study reported here was to examine the effects of surface modification by sand blasting and acid-etching (SLA) on the microstructure and fatigue performance of coarse-grained and ultrafine-grained (UFG) commercially pure titanium. Finer grain sizes, produced by equal channel angular pressing, resulted in lower values of surface roughness in SLA-processed material. This effect was associated with greater resistance of the UFG structure to plastic deformation. The fatigue properties of UFG Ti were found to be superior to those of coarse-grained Ti and conventional Ti-6Al-4V, both before and after SLA-treatment.

  11. Bituminous sands : tax issues

    Energy Technology Data Exchange (ETDEWEB)

    Patel, B. [PricewaterhouseCoopers LLP, Calgary, AB (Canada)

    2004-07-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs.

  12. The effect of nanoparticles and humic acid on technology critical element concentrations in aqueous solutions with soil and sand.

    Science.gov (United States)

    Stepka, Zane; Dror, Ishai; Berkowitz, Brian

    2017-08-23

    As a consequence of their growing use in electronic and industrial products, increasing amounts of technology critical elements (TCEs) are being released to the environment. Currently little is known about the fate of many of these elements. Initial research on their potential environmental impact identifies TCEs as emerging contaminants. TCE movement in the environment is often governed by water systems. Research on "natural" waters so far demonstrates that TCEs tend to be associated with suspended particulate matter (SPM), which influences TCE aqueous concentrations (here: concentration of TCEs in dissolved form and attached to SPM) and transport. However, the relative potential of different types of SPM to interact with TCEs is unknown. Here we examine the potential of various types of particulate matter, namely different nanoparticles (NPs; Al2O3, SiO2, CeO2, ZnO, montmorillonite, Ag, Au and carbon dots) and humic acid (HA), to impact TCE aqueous concentrations in aqueous solutions with soil and sand, and thus influence TCE transport in soil-water environments. We show that a combination of NPs and HA, and not NPs or HA individually, increases the aqueous concentrations of TCEs in soil solutions, for all tested NPs regardless of their type. TCEs retained on SPM, however, settle with time. In solutions with sand, HA alone is as influential as NPs+HA in keeping TCEs in the aqueous phase. Among NPs, Ag-NPs and Au-NPs demonstrate the highest potential for TCE transport. These results suggest that in natural soil-water environments, once TCEs are retained by soil, their partitioning to the aqueous phase by through-flowing water is unlikely. However, if TCEs are introduced to soil-water environments as part of solutions rich in NPs and HA, it is likely that NP and HA combinations can increase TCE stability in the aqueous phase and prevent their retention on soil and sand, thus facilitating TCE transport. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Thermal Properties of oil sand

    Science.gov (United States)

    LEE, Y.; Lee, H.; Kwon, Y.; Kim, J.

    2013-12-01

    Thermal recovery methods such as Cyclic Steam Injection or Steam Assisted Gravity Drainage (SAGD) are the effective methods for producing heavy oil or bitumen. In any thermal recovery methods, thermal properties (e.g., thermal conductivity, thermal diffusivity, and volumetric heat capacity) are closely related to the formation and expansion of steam chamber within a reservoir, which is key factors to control efficiency of thermal recovery. However, thermal properties of heavy oil or bitumen have not been well-studied despite their importance in thermal recovery methods. We measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of 43 oil sand samples from Athabasca, Canada, using a transient thermal property measurement instrument. Thermal conductivity of 43 oil sand samples varies from 0.74 W/mK to 1.57 W/mK with the mean thermal conductivity of 1.09 W/mK. The mean thermal diffusivity is 5.7×10-7 m2/s with the minimum value of 4.2×10-7 m2/s and the maximum value of 8.0×10-7 m2/s. Volumetric heat capacity varies from 1.5×106 J/m3K to 2.11×106 J/m3K with the mean volumetric heat capacity of 1.91×106 J/m3K. In addition, physical and chemical properties (e.g., bitumen content, electric resistivity, porosity, gamma ray and so on) of oil sand samples have been measured by geophysical logging and in the laboratory. We are now proceeding to investigate the relationship between thermal properties and physical/chemical properties of oil sand.

  14. Lund Sand No 0

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Jakobsen, Finn Rosendal

    During the last 15 years the Geotechnical Engineering Group (GEG) at Aalborg University has performed triaxial tests with a sand called Lund No 0. Lund No 0 is a graded sand from a gravel pit near Horsens in Denmark. For the classification of the sand the following tests have been performed: Sieve...... test, Grain density, ds, Maximum, emax, and minimum, emin, void ratio. The strength parameters of Lund No 0 are detennined by some drained and undrained triaxial tests in the Danish Triaxial Cell. The Danish Triaxial Cell prescribes smooth pressure heads and specimens with equal height and diameter....... Four series with Id equal to 0.92, 0.87 0.76 and 0.55 have been performed....

  15. Effect of Tube Length on Transport of Multi-Wall Nanotubes (MWNTs) in a Water-Saturated Quartz Sand

    Science.gov (United States)

    Wang, Y.; Baek, J.; Kim, J.; Pennell, K. D.

    2009-12-01

    With expanding commercial interests from various application areas, the production of carbon nanotubes (CNTs) in large scale is expected to grow rapidly. The inevitable release of CNTs into the environment and identification of the cytotoxicity of dispersed CNTs prompt the necessity of understanding their transport behavior in porous media. In this study, one-dimensional column experiments were conducted to assess the transport and retention of multi-wall nanotubes (MWNTs) in water-saturated 40-50 mesh Ottawa sand as a function of of tube length. In order to avoid damages to nanotube length by ultrasonication or superacids (e.g., HNO3), a chemical modification method involving a mild acid treatment was adopted to prepare suspensions of MWNTs with three different manufacture-reported (MR) lengths (0.5-2, 10-20, and 50 μm). For each experiment, a pulse (e.g., 5 pore volumes) of MWNT suspension was introduced into the column, followed by 3 pore volumes of MWNT-free solution elution. Measured concentrations of MWNTs in effluent and dissected solid samples were used to construct effluent breakthrough curves and retention profiles, respectively. For an input concentration of ca. 90 mg/L, MWNTs breakthrough concentrations decreased with the increasing MR length. Even with an MR length of 50 μm, MWNTs were readily transported through the packed bed, where ca. 80% of total injected nanotubes passed through the column. While the retention of MWNTs increased with MR length, concentrations of retained nanotubes decreased hyper-exponentially with distance from the column inlet. Further analysis of these findings suggests that clean-bed filtration theory alone is not sufficient to describe MWNT transport and retention behavior in a water-saturated quartz sand.

  16. An Effective Experimental Device Design for Monitoring the Sand Signal Out of the Heavy Oil%一种能有效监测稠油出砂信号的室内实验装置设计

    Institute of Scientific and Technical Information of China (English)

    刘刚; 韩金良; 陈超; 杨全枝; 李玉红

    2012-01-01

    稠油油井生产的适度出砂开采技术需要一种有效简便的出砂实时监测方式来监测油井生产的出砂状况.油井的过度出砂能严重损坏设备,影响生产.国内目前油井的出砂监测方法主要包括出砂声测法和电阻法,但是这两种方法对于稠油的出砂监测都存在一些问题.因此,实验室内设计了一种用于稠油出砂监测的一次仪表,主要是通过采用压电式高频加速度传感器来接收携砂流体中砂粒撞击管壁产生的振动信号来监测稠油的出砂状况.为验证这一装置设计的有效性,在实验室内建立了一套完整的稠油出砂监测系统.实验采用150目石英砂粒,含砂量从0‰到5‰,利用高黏度的齿轮油作为携砂流体.实验结果表明,这种一次仪表设计能够有效实时监测稠油的出砂信号,具有很好的应用性.%The moderate sand mining technology of heavy oil field need a kind of effective and sample real-time monitoring system for monitoring the signal of sand out, over sand can damage the device severely ,affecting production. Sand monitoring methods include sand acoustic method and resistance method, but there are some problems in these two methods, so a method is designed for heavy oil sand monitoring instrumentation through the use of the piezoelectric high-frequency acceleration sensor to receive the sand hit the wall in sand-carrying fluid vibration signals to monitor the status of the heavy oil out of sand. In order to verify the effectiveness of the design, a complete is established set of heavy oil sand production monitoring system in laboratory. Using 150 mesh quartz sand, the sand content from 0 ‰ to 5 ‰, with high-viscosity gear oil as a sand-carrying fluid. Experimental results show that this design can effectively monitoring the sand signal from heavy oil real-time, with a good effect.

  17. Explaining the Modality Effect in Multimedia Learning: Is It Due to a Lack of Temporal Contiguity with Written Text and Pictures?

    Science.gov (United States)

    Schuler, Anne; Scheiter, Katharina; Rummer, Ralf; Gerjets, Peter

    2012-01-01

    The study examined whether the modality effect is caused by either high visuo-spatial load or a lack of temporal contiguity when processing written text and pictures. Students (N = 147) viewed pictures on the development of tornados, which were accompanied by either spoken or written explanations presented simultaneously with, before, or after the…

  18. UK Frac Sand Resources

    OpenAIRE

    Mitchell, C J

    2015-01-01

    Although still just a glimmer in the gas man’s eye, the prospect of shale hydrocarbon (oil and gas) development in the UK has many companies thinking about the industrial minerals it will require. Chief amongst these is silica sand which is used as a ‘proppant’ in the hydraulic fracturing, or ‘fracking’, of shales to help release the gas. The UK has large resources of sand and sandstone, of which only a small proportion have the necessary technical properties that classify them as ‘silica san...

  19. COST-EFFECTIVENESS OF LOWER TARGETS FOR BLOOD PRESSURE AND LDL CHOLESTEROL IN DIABETES: THE STOP ATHEROSCLEROSIS IN NATIVE DIABETICS STUDY (SANDS)

    Science.gov (United States)

    Wilson, Charlton; Huang, Chun-Chih; Shara, Nawar; Howard, Barbara V.; Fleg, Jerome L.; Henderson, Jeffrey A.; Howard, Wm. James; Huentelman, Heather; Lee, Elisa T.; Mete, Mihriye; Russell, Marie; Galloway, James M.; Silverman, Angela; Stylianou, Mario; Umans, Jason; Weir, Matthew R.; Yeh, Fawn; Ratner, Robert E.

    2010-01-01

    Background The Stop Atherosclerosis in Native Diabetics Study (SANDS) reported cardiovascular benefit of aggressive versus standard treatment targets for both low-density lipoprotein cholesterol (LDL-C) and blood pressure (BP) in diabetic individuals. Objective In this analysis, we examined within trial cost-effectiveness of aggressive targets of LDL-C ≤70 mg/dL and systolic blood pressure (SBP) ≤115 mmHg vs. standard targets of LDL-C ≤100 mg/dL and SBP ≤130 mmHg. Design Randomized, open label blinded-to-endpoint 3-year trial. Data Sources SANDS clinical trial database, Quality of Wellbeing (QWB) survey, Centers for Medicare and Medicaid Services, Wholesale Drug Prices. Target Population American Indians ≥ age 40 years with type 2 diabetes and no prior cardiovascular events. Time Horizon April 2003-July 2007. Perspective Health payer. Interventions Participants were randomized to aggressive vs. standard groups with treatment algorithms defined for both. Outcome Measures Incremental cost-effectiveness. Results of Base-Case Analysis Compared with the standard group, the aggressive group had slightly lower costs of medical services ($-116), but a 54% higher cost for BP medication ($1,242) and a 116% higher cost for lipid-lowering medication ($2,863), resulting in an increased cost of $3,988 over 3 years. Those in the aggressively treated group gained 0.0480 quality-adjusted life-years (QALY) over the standard group. Using a 3% discount rate for costs and outcomes, the resulting cost per QALY was $82,589. Results of Sensitivity Analysis Using a 25%, 50%, and 75% reduction in drug costs resulted in a cost per QALY of $61,329, $40,070, and $18,810, respectively. Limitations This study was limited by use of a single ethnic group and by its 3-year duration. Conclusions Within this 3-year study, treatment to lower BP and LDL-C below standard targets was not cost-effective due to the cost of the additional medications required to meet the lower targets. With the

  20. Effect of sillimanite beach sand composition on mullitization and properties of Al2O3–SiO2 system

    Indian Academy of Sciences (India)

    H S Tripathi; B Mukherjee; S K Das; A Ghosh; G Banerjee

    2003-02-01

    Mullite was developed by reaction sintering of sillimanite beach sand and calcined alumina. Two varieties of sillimanite beach sand viz. S and Z having different compositions were selected. Synthesis and properties of mullite were very much dependent on the sillimanite beach sand composition. Presence of higher amount of impurities in the Z-variety of sillimanite sand favours the densification by liquid phase formation. Presence of zircon in Z-variety increases the hardness and fracture toughness. Alumina addition improves the mechanical/thermomechanical properties of the samples. Mullite retains the usual orthorhombic habit of sillimanite. Rounded to sub rounded zirconia dispersed within the mullite matrix of the sample ZA is noticed.

  1. Building with Sand

    Science.gov (United States)

    Ashbrook, Peggy

    2010-01-01

    Children playing in damp sand invariably try to make a tower or a tunnel. By providing experiences with a variety of materials, alone and together, teachers set up the conditions for children to learn through their senses and ensure that a class approaches a topic with a common set of experiences to build on. Learning about the properties of…

  2. Faraday, Jets, and Sand

    NARCIS (Netherlands)

    Sandtke, M.; van der Meer, Roger M.; Versluis, Andreas Michel; Lohse, Detlef

    2003-01-01

    When a 6-mm layer of fine sand with an average grain size of 40 µm is poured into a cylindrical container and shaken vertically, thin jets are seen to emerge from an airy cloud of grains, almost like protuberances from the corona of the sun. A quasi two-dimensional setup reveals the jet-formation

  3. Building with Sand

    Science.gov (United States)

    Ashbrook, Peggy

    2010-01-01

    Children playing in damp sand invariably try to make a tower or a tunnel. By providing experiences with a variety of materials, alone and together, teachers set up the conditions for children to learn through their senses and ensure that a class approaches a topic with a common set of experiences to build on. Learning about the properties of…

  4. Speleothems and Sand Castles

    Science.gov (United States)

    Hance, Trevor; Befus, Kevin

    2015-01-01

    The idea of building sand castles evokes images of lazy summer days at the beach, listening to waves crash, enjoying salty breezes, and just unplugging for a while to let our inner child explore the wonderful natural toys beneath our feet. The idea of exploring caves might evoke feelings and images of claustrophobia or pioneers and Native…

  5. Virksomhedens sande ansigt

    DEFF Research Database (Denmark)

    Lundholt, Marianne Wolff

    2017-01-01

    Er modhistorier en byrde eller en styrke i forandringsprocesser? Hvad stiller vi op, når adgangen til organisationens sande identitet går gennem medarbejdernes modhistorier? Når vi sammenholder denne erkendelse med vores viden om, at medarbejdere helt naturligt afholder sig fra at videregive disse...

  6. Sand (CSW4)

    CSIR Research Space (South Africa)

    Estuarine and Coastal Research Unit

    1982-12-01

    Full Text Available This report is one of a series on Cape Estuaries being published under the general title "The Estuaries of the Cape, Part 2". The report provides information on sand estuary: historical background, abiotic and biotic characteristics. It is pointed...

  7. Sand supply to beaches

    Science.gov (United States)

    Aagaard, Troels

    2017-04-01

    In most cases, beaches and dunes are built by sand that has been transported onshore from the shoreface. While this has been known for a long time, we are still not able to quantitatively predict onshore sediment transport and sand supply to beaches. Sediment transport processes operating during brief, high-energy stormy conditions - when beaches erode and sand moves offshore - are fairly well known and they can be modelled with a reasonable degree of confidence. However, the slower onshore sand transport leading to beach recovery under low-to-moderate energy conditions - and the reason why beaches and dunes exist in the first place - is not yet well understood. This severely limits our capability to understand and predict coastal behaviour on long time scales, for example in response to changing sea level or wave conditions. This paper will discuss issues and recent developments in sediment transport measurement and prediction on the lower and upper shoreface and into the swash zone. The focus will be on the integration and upscaling of small-scale deterministic process measurements into parametric models that may increase modelling capabilities of coastal behaviour on larger temporal and spatial scales.

  8. Lack of correlation between the antiarrhythmic effect of L-propionylcarnitine on reoxygenation-induced arrhythmias and its electrophysiological properties.

    OpenAIRE

    Barbieri, M.; Carbonin, P. U.; Cerbai, E.; Gambassi, G; Lo Giudice, P.; Masini, I.; Mugelli, A.; Pahor, M.

    1991-01-01

    1. The antiarrhythmic effect of L-propionylcarnitine (L-PC) was evaluated in the guinea-pig isolated heart; arrhythmias were induced with hypoxia followed by reoxygenation and by digitalis intoxication. 2. L-PC 1 microM, was found to be the minimal but effective antiarrhythmic concentration against reoxygenation-induced ventricular fibrillation. No antiarrhythmic effect was observed against digitalis-induced arrhythmias. D-Propionylcarnitine, L-carnitine and propionic acid did not exert antia...

  9. Erosion phenomena in sand moulds

    Directory of Open Access Journals (Sweden)

    A. Chojecki

    2008-03-01

    Full Text Available Authors studicd the erosion phcnorncna in sand moulds pured with cast iron. Thc study comprises an evaluation of erosionresistance of thc three sands: grccn sand. sand bondcd with inorganic or organic bindcr. It was concluded that thc most resistant is [heclassic green sand with thc addition of 5 B coal dust. Resistance of the sand with organic binder is generally weak and dcvnds onkind of used raisin. Spccinl nztcntion was paid to the sands with no organic bindcr watcr glass and phospha~c. It was Sound that thcirrcsistance depends on dehydratation conditions. When the mould is stored in law humidity of atmosphcrc the very strong crosion canbe expected. It rcsul ts hrn thc micro fractures in the bridges of binders, joining the grains of the sable. This phcnomcna facilitates thetearing away of fragments of sand [tom the surface

  10. Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux

    Science.gov (United States)

    Ayoub, F.; Avouac, J.-P.; Newman, C. E.; Richardson, M. I.; Lucas, A.; Leprince, S.; Bridges, N. T.

    2014-09-01

    Coupling between surface winds and saltation is a fundamental factor governing geological activity and climate on Mars. Saltation of sand is crucial for both erosion of the surface and dust lifting into the atmosphere. Wind tunnel experiments along with measurements from surface meteorology stations and modelling of wind speeds suggest that winds should only rarely move sand on Mars. However, evidence for currently active dune migration has recently accumulated. Crucially, the frequency of sand-moving events and the implied threshold wind stresses for saltation have remained unknown. Here we present detailed measurements of Nili Patera dune field based on High Resolution Imaging Science Experiment images, demonstrating that sand motion occurs daily throughout much of the year and that the resulting sand flux is strongly seasonal. Analysis of the seasonal sand flux variation suggests an effective threshold for sand motion for application to large-scale model wind fields (1-100 km scale) of τs=0.01±0.0015 N m-2.

  11. On Pluvial Compaction of Sand

    DEFF Research Database (Denmark)

    Jacobsen, Moust

    At the Institute of Civil Engineering in Aalborg model tests on dry sand specimens have been carried out during the last five years. To reduce deviations in test results, the sand laying technique has been carefully studied, and the sand mass spreader constructed. Preliminary results have been...

  12. Lack of correlation between the antiarrhythmic effect of L-propionylcarnitine on reoxygenation-induced arrhythmias and its electrophysiological properties.

    Science.gov (United States)

    Barbieri, M; Carbonin, P U; Cerbai, E; Gambassi, G; Lo Giudice, P; Masini, I; Mugelli, A; Pahor, M

    1991-01-01

    1. The antiarrhythmic effect of L-propionylcarnitine (L-PC) was evaluated in the guinea-pig isolated heart; arrhythmias were induced with hypoxia followed by reoxygenation and by digitalis intoxication. 2. L-PC 1 microM, was found to be the minimal but effective antiarrhythmic concentration against reoxygenation-induced ventricular fibrillation. No antiarrhythmic effect was observed against digitalis-induced arrhythmias. D-Propionylcarnitine, L-carnitine and propionic acid did not exert antiarrhythmic effects. 3. During hypoxia and reoxygenation L-PC consistently prevented the rise of the diastolic left ventricular pressure, and significantly reduced the release of the cardiac enzymes creatine kinase (CK) and lactic dehydrogenase (LDH). 4. The electrophysiological effects of L-PC were then studied on either normal sheep cardiac Purkinje fibres or those manifesting oscillatory after potentials induced by barium or strophanthidin. 5. L-PC (1 and 10 microM) did not significantly modify action potential characteristics and contractility of normal Purkinje fibres, or the amplitude of OAP induced by strophanthidin or barium. 6. It is concluded that the antiarrhythmic action of L-PC on reoxygenation-induced arrhythmias is not correlated with its direct electrophysiological effects studied on normoxic preparations.

  13. Antidepressive and BDNF effects of enriched environment treatment across ages in mice lacking BDNF expression through promoter IV

    Science.gov (United States)

    Jha, S; Dong, B E; Xue, Y; Delotterie, D F; Vail, M G; Sakata, K

    2016-01-01

    Reduced promoter IV-driven expression of brain-derived neurotrophic factor (BDNF) is implicated in stress and major depression. We previously reported that defective promoter IV (KIV) caused depression-like behavior in young adult mice, which was reversed more effectively by enriched environment treatment (EET) than antidepressants. The effects of promoter IV-BDNF deficiency and EET over the life stages remain unknown. Since early-life development (ED) involves dynamic epigenetic processes, we hypothesized that EET during ED would provide maximum antidepressive effects that would persist later in life due to enhanced, long-lasting BDNF induction. We tested this hypothesis by determining EET effects across three life stages: ED (0–2 months), young adult (2–4 months), and old adult (12–14 months). KIV mice at all life stages showed depression-like behavior in the open-field and tail-suspension tests compared with wild-type mice. Two months of EET reduced depression-like behavior in ED and young adult, but not old adult mice, with the largest effect in ED KIV mice. This effect lasted for 1 month after discontinuance of EET only in ED mice. BDNF protein induction by EET in the hippocampus and frontal cortex was also the largest in ED mice and persisted only in the hippocampus of ED KIV mice after discontinuance of EET. No gender-specific effects were observed. The results suggest that defective promoter IV causes depression-like behavior, regardless of age and gender, and that EET during ED is particularly beneficial to individuals with promoter IV-BDNF deficiency, while additional treatment may be needed for older adults. PMID:27648918

  14. Expandable sand screens: from novel concept to proven sand control technique

    Energy Technology Data Exchange (ETDEWEB)

    Metcalfe, Paul; Jones, Colin; Ballard, Tracey; Beare, Steve; Hillis, Dave [Weatherford International Inc., Houston, TX (United States)

    2004-07-01

    Expandable Sand Screens (ESS) have proved a viable alternative to gravel packing for sand control. With over 300 installations worldwide, analysis of their use has confirmed that ESS offers excellent production performance and sand control reliability in Open hole. This paper presents details of a global survey on ESS performance that gives accurate information on production performance, sand exclusion reliability and cost effectiveness in Open hole and cased hole application scenarios. This paper also discusses the role and effect of compliant expansion in observed productivity performance and skin values. The rock mechanical, reservoir characterization and metallurgical requirements of ESS systems are also investigated. Finally, the latest advances of the technology for use within the reservoir are explained. This paper demonstrates how the combination of ESS and Expandable Zonal Isolation devices can offer cased hole functionality (in terms of zonal isolation) in combination with Open hole levels of production performance (from the ESS). (author)

  15. Lack of transgene and glyphosate effects on yield, and mineral and amino acid content of glyphosate-resistant soybean.

    Science.gov (United States)

    Duke, Stephen O; Rimando, Agnes M; Reddy, Krishna N; Cizdziel, James V; Bellaloui, Nacer; Shaw, David R; Williams, Martin M; Maul, Jude E

    2017-05-25

    There has been controversy as to whether the glyphosate resistance gene and/or glyphosate applied to glyphosate-resistant (GR) soybean affect the content of cationic minerals (especially Mg, Mn and Fe), yield and amino acid content of GR soybean. A two-year field study (2013 and 2014) examined these questions at sites in Mississippi, USA. There were no effects of glyphosate, the GR transgene or field crop history (for a field with both no history of glyphosate use versus one with a long history of glyphosate use) on grain yield. Furthermore, these factors had no consistent effects on measured mineral (Al, As, Ba, Cd, Ca, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Ni, Pb, Rb, Se, Sr, Tl, U, V, Zn) content of leaves or harvested seed. Effects on minerals were small and inconsistent between years, treatments and mineral, and appeared to be random false positives. No notable effects on free or protein amino acids of the seed were measured, although glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), were found in the seed in concentrations consistent with previous studies. Neither glyphosate nor the GR transgene affect the content of the minerals measured in leaves and seed, harvested seed amino acid composition, or yield of GR soybean. Furthermore, soils with a legacy of GR crops have no effects on these parameters in soybean. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. Sand Dunes Fixation in Baiji District, Iraq

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This study was carried out at Sand Dunes Stabilization Researches Station in Baiji district (230 ln north of Baghdad, Iraq) to evaluate the effects of local soil conditioners manufactured from oil derivatives and plant residuals on sand dunes fixation as the first step for sand dunes stabilization. The results indicate that the fuel oil has the first place in improving wind erosion parameters in the study area, such as increasing mean weight diameter, dry aggregates percentage, the needed time for complete disaggregation by dry sieving, and decreasing the disaggregation rates. Bitumen emulsion occupies the second place, while the plant residuals occupies the third place and has slight effects on the studied parameters. Effects of conditioners on natural vegetation cover are negative in oil derivatives treatments,while positive in plants residuals treatments.

  17. Peripheral cardiovascular actions of SR 58611 A, a beta 3-adrenoceptor agonist, in the dog: lack of central effect.

    Science.gov (United States)

    Montastruc, J L; Verwaerde, P; Pelat, M; Galitzky, J; Langin, D; Lafontan, M; Berlan, M

    1999-01-01

    In order to investigate the putative role of beta3-adrenoceptors in central and peripheral cardiovascular regulations, the effects of intracisternal (i.c.) and intravenous (i.v.) injections of SR 58611 A (10, 50, 100 and 200 nmol kg-1), a selective beta3-adrenoceptor agonist, were investigated in chloralose anaesthetized dogs. In normal dogs, i.v. SR 58611 A (100 and 200 nmol kg-1) induced a dose-dependent increase in heart rate with no change in blood pressure. After i.c. injection, SR 58611 A failed to modify blood pressure and heart rate (except at the highest dose 200 nmol kg-1 which induced a positive chronotropic effect). The positive chronotropic effect of SR 58611 A (200 nmol kg-1) appeared earlier and was significantly more pronounced after i.v. than i.c. administration. The positive chronotropic effect of i.v. SR 58611 A (200 nmol kg-1) was reduced by pretreatment with beta-adrenoceptor antagonists [propranolol, nadolol, bupranolol or the beta3-adrenoceptor selective antagonist, SR 59230 A (2 mg kg-1 i.v.)] and suppressed after sinoaortic denervation (i.e. after removal of vagal tone to the heart). These experiments do not show evidence for a primary central cardiovascular effect of SR 58611 A. The positive chronotropic effect of i.v. SR 58611 A is mainly of peripheral origin and can be attributed to a baroreceptor-mediated reflex due to the beta3-adrenoceptor mediated vasodilation with an increase in sympathetic tone and a reduction in vagal tone to the heart.

  18. Effects of Different Straw and Sand and Gravel Cover Thickness on Soil Moisture Evaporation%不同秸秆和砂石覆盖厚度对土壤水分蒸发的影响

    Institute of Scientific and Technical Information of China (English)

    白玮

    2016-01-01

    为了揭示不同秸秆和砂石覆盖厚度对抑制土壤水分蒸发的效果,本文通过室外模拟试验,研究了不同秸秆和砂石覆盖厚度对土壤水分蒸发的影响。试验设置无覆盖(CK)、覆秸秆3cm(S1)、覆秸秆5cm(S2)、覆秸秆10cm(S3)、覆砂3cm(S4)、覆砂5cm (S5)、覆砂10cm(S6)这7种形式。结果表明:在不同覆盖厚度条件下,秸秆和砂石覆盖均可有效抑制土壤水分蒸发,随覆盖厚度的增加,保水效果越好。在相同覆盖厚度条件下,秸秆覆盖的保水效果优于砂石覆盖的,随覆盖厚度的增加,秸秆和砂石覆盖的保水效果差异减小。%To reveal the effect on inhibition of soil water evaporation under the different straw and sand cover thickness, this paper studied the influence of different straw and sand covering thickness on soil moisture evaporation by outdoor simulation test. The experiment set up non mulching (CK), covering straw 3cm (S1), covering straw 5cm (S2), covering straw 10cm (S3), sand 3cm (S4), sand 5cm (S5), sand covered 10cm (S6) these 7 forms. The results showed that: under the conditions of different cover thickness, straw and sand and gravel mulch can effectively inhibit the evaporation of soil moisture, with the increase of cover thickness, the better the water retention effect. Under the same cover thickness, the water retaining effect of straw mulching is better than that of sand and gravel, and the water retention effect of straw and sand and gravel cover is decreased with the increase of the cover thickness.

  19. Lack of effect of Tai Chi Chuan in preventing falls in elderly people living at home: a randomized clinical trial.

    NARCIS (Netherlands)

    Logghe, I.H.; Zeeuwe, P.E.; Verhagen, A.P.; Wijnen-Sponselee, R.M.; Willemsen, S.P.; Bierma-Zeinstra, S.M.; Rossum, E. van; Faber, M.J.; Faber, B.W.

    2009-01-01

    OBJECTIVES: To evaluate the effectiveness of Tai Chi Chuan in fall prevention in elderly people living at home with a high risk of falling. DESIGN: Randomized controlled trial. SETTING: Two industrial towns in the western part of the Netherlands. PARTICIPANTS: Two hundred sixty-nine elderly people (

  20. Lack of effect of statins on maintenance of normal sinus rhythm following electrical cardioversion of persistent atrial fibrillation.

    Science.gov (United States)

    Bhardwaj, A; Sood, N A; Kluger, J; Coleman, C I

    2010-07-01

    Randomised controlled trials evaluating the effect of statin use on maintenance of normal sinus rhythm (NSR) after electrical cardioversion (ECV) of persistent atrial fibrillation (AF) have demonstrated conflicting results. However, many of these trials were of relatively small size and thus underpowered to adequately evaluate this end-point. The aim of this study was to conduct a meta analysis evaluating the effect of statin use on maintenance of NSR after ECV of persistent AF. Randomised controlled trials evaluating the use of statins to maintain NSR after ECV of AF were identified through a systematic search including Medline (1950 through December 2009), the Cochrane CENTRAL Register (4th quarter, 2009) and a manual review of references without any language restrictions. Pooled estimates of effect are reported as relative risks (RRs) with accompanying 95% confidence intervals (CIs) using a random-effects model. Four trials (n = 424; range: 48-212) were identified and subject to meta analysis. Evaluated statins included atorvastatin 10 and 80 mg and pravastatin 40 mg/day. Over a mean of 2.1 months (range: 1-3 months) statins did not increase the likelihood of maintaining NSR following ECV (RR, 1.12; 95%CI, 0.85-1.46) compared with control. Current evidence does not suggest that statins are associated with an increased probability of maintaining NSR following ECV of persistent AF.

  1. The Effect of Air Density on Sand Transport Structures and the Adobe Abrasion Profile: A Field Wind-Tunnel Experiment Over a Wide Range of Altitude

    Science.gov (United States)

    Han, Qingjie; Qu, Jianjun; Dong, Zhibao; Zu, Ruiping; Zhang, Kecun; Wang, Hongtao; Xie, Shengbo

    2013-11-01

    Aeolian sand transport results from interactions between the surface and the airflow above. Air density strongly constrains airflow characteristics and the resulting flow of sand, and therefore should not be neglected in sand transport models. In the present study, we quantify the influence of air density on the sand flow structure, sand transport rate, adobe abrasion profiles, and abrasion rate using a portable wind-tunnel in the field. For a given wind speed, the flow's ability to transport sand decreases at low air density, so total sand transport decreases, but the saltation height increases. Thus, the damage to human structures increases compared with what occurs at lower altitudes. The adobe abrasion rate by the cloud of blowing sand decreases exponentially with increasing height above the surface, while the wind erosion and dust emission intensity both increase with increasing air density. Long-term feedback processes between air density and wind erosion suggest that the development of low-altitude areas due to long-term deflation plays a key role in dust emission, and will have a profound significance for surface Aeolian processes and geomorphology.

  2. Optimising the composition of natural moulding sands including thermal aspects

    Directory of Open Access Journals (Sweden)

    Jerzy St. Kowalski

    2011-04-01

    Full Text Available The paper discusses the problem of the choice of the moulding sand mixture composition in terms of the sand behaviour in contact withmolten metal. Studies of high-temperature phenomena make assessment of the sand composition applicability under real operatingconditions possible, thus leading to the elimination of sand-originating casting defects. The research was conducted on selected moulding materials included in the composition of traditional moulding sand mixtures without the addition of carbon. The effect of moulding sand composition and moisture content on the linear dilatation and stress-induced allotropic changes of quartz was examined. The analysis of these phenomena was based on 3D charts and maps generated from data collected during the tests.

  3. Lack of effect of aerial ammonia on atrophic rhinitis and pneumonia induced by Mycoplasma hyopneumoniae and toxigenic Pasteurella multocida

    DEFF Research Database (Denmark)

    Andreasen, Morten; Bækbo, P.; Nielsen, Jens

    2000-01-01

    The objective of this experimental study was to determine the effects of aerial ammonia on disease development and bacterial colonization in weaned pigs inoculated with toxigenic Pasteurella multocida and Mycoplasma hyopneumoniae. Two groups of 10 pigs each were continuously exposed to 50 and 100 p......, tonsils, lungs and kidneys, or the average daily weight gain. The recovery of toxigenic P. multocida from nasal swabs following inoculation was significantly greater in pigs exposed to 50 p.p.m. ammonia or more as compared to the control group. In conclusion, high levels of ammonia combined...... with inoculations with M. hyopneumoniae and toxigenic P. multocida had no significant effect on disease development, but may have enhanced colonization by toxigenic P. multocida on the nasal turbinates....

  4. Mast cells are responsible for the lack of anti-inflammatory effects of morphine in CBA mice

    Directory of Open Access Journals (Sweden)

    Elzbieta Stankiewicz

    2004-01-01

    Full Text Available BACKGROUND and aim: Morphine co-injection has anti-inflammatory effects on zymosan-induced peritonitis in several strains of mice except that of CBA. As peritoneal mast cells (pMCs are much more numerous in CBA mice than in SWISS mice, the role of pMCs in morphine-modulated zymosan peritonitis is compared in CBA and SWISS males.

  5. Abnormal response to stress and impaired NPS-induced hyperlocomotion, anxiolytic effect and corticosterone increase in mice lacking NPSR1

    OpenAIRE

    Zhu, Hongyan; Mingler, Melissa K; McBride, Melissa L.; Murphy, Andrew J.; Valenzuela, David M.; Yancopoulos, George D.; Williams, Michael T.; Vorhees, Charles V.; Rothenberg, Marc E.

    2010-01-01

    NPSR1 is a G protein coupled receptor expressed in multiple brain regions involved in modulation of stress. Central administration of NPS, the putative endogenous ligand of NPSR1, can induce hyperlocomotion, anxiolytic effects and activation of the HPA axis. The role of NPSR1 in the brain remains unsettled. Here we used NPSR1 gene-targeted mice to define the functional role of NPSR1 under basal conditions on locomotion, anxiety- and/or depression-like behavior, corticosterone levels, acoustic...

  6. Sand hazards on tourist beaches.

    Science.gov (United States)

    Heggie, Travis W

    2013-01-01

    Visiting the beach is a popular tourist activity worldwide. Unfortunately, the beach environment is abundant with hazards and potential danger to the unsuspecting tourist. While the traditional focus of beach safety has been water safety oriented, there is growing concern about the risks posed by the sand environment on beaches. This study reports on the death and near death experience of eight tourists in the collapse of sand holes, sand dunes, and sand tunnels. Each incident occurred suddenly and the complete burial in sand directly contributed to the victims injury or death in each case report.

  7. Ionic imbalance and lack of effect of adjuvant treatment with methylene blue in the hamster model of leptospirosis

    Directory of Open Access Journals (Sweden)

    Cleiton Silva Santos

    2013-06-01

    Full Text Available Leptospirosis in humans usually involves hypokalaemia and hypomagnesaemia and the putative mechanism underlying such ionic imbalances may be related to nitric oxide (NO production. We previously demonstrated the correlation between serum levels of NO and the severity of renal disease in patients with severe leptospirosis. Methylene blue inhibits soluble guanylyl cyclase (downstream of the action of any NO synthase isoforms and was recently reported to have beneficial effects on clinical and experimental sepsis. We investigated the occurrence of serum ionic changes in experimental leptospirosis at various time points (4, 8, 16 and 28 days in a hamster model. We also determined the effect of methylene blue treatment when administered as an adjuvant therapy, combined with late initiation of standard antibiotic (ampicillin treatment. Hypokalaemia was not reproduced in this model: all of the groups developed increased levels of serum potassium (K. Furthermore, hypermagnesaemia, rather than magnesium (Mg depletion, was observed in this hamster model of acute infection. These findings may be associated with an accelerated progression to acute renal failure. Adjuvant treatment with methylene blue had no effect on survival or serum Mg and K levels during acute-phase leptospirosis in hamsters.

  8. Capturing phosphates with iron enhanced sand filtration.

    Science.gov (United States)

    Erickson, Andrew J; Gulliver, John S; Weiss, Peter T

    2012-06-01

    Most treatment practices for urban runoff capture pollutants such as phosphorus by either settling or filtration while dissolved phosphorus, typically as phosphates, is untreated. Dissolved phosphorus, however, represents an average 45% of total phosphorus in stormwater runoff and can be more than 95%. In this study, a new stormwater treatment technology to capture phosphate, called the Minnesota Filter, is introduced. The filter comprises iron filings mixed with sand and is tested for phosphate removal from synthetic stormwater. Results indicate that sand mixed with 5% iron filings captures an average of 88% phosphate for at least 200 m of treated depth, which is significantly greater than a sand filter without iron filings. Neither incorporation of iron filings into a sand filter nor capture of phosphates onto iron filings in column experiments had a significant effect on the hydraulic conductivity of the filter at mixtures of 5% or less iron by weight. Field applications with up to 10.7% iron were operated over 1 year without detrimental effects upon hydraulic conductivity. A model is applied and fit to column studies to predict the field performance of iron-enhanced sand filters. The model predictions are verified through the predicted performance of the filters in removing phosphates in field applications. Practical applications of the technology, both existing and proposed, are presented so stormwater managers can begin implementation.

  9. Sand control mechanism analysis of metallic wool screen

    Energy Technology Data Exchange (ETDEWEB)

    Yongquan, H.; Jinzhou, Z.; Zhinjun, W.; Zhaofeng, L. [Southwest Petroleum Institute, China, (China); Lei, Y. [Liaohe petroleum Administration, China, (China)

    1997-08-01

    A filter prepacked with metallic wool was developed and claimed to have been effectively used on thermal and unconsolidated sand oil wells. Structural features of the filter screen and the factors having a bearing on its sand control function, such as particle characteristics, fluid properties, environmental conditions, and the filtering characteristics of metallic wool, were discussed. Some experimental results have been provided to illustrate desirable characteristics and advantages. According to this evidence, sanding velocity is highest at the beginning, stabilizing gradually. Production pressure drop must be appropriately adjusted to achieve best results with well sanding control. 9 refs., 1 tab., 5 figs.

  10. PROCESSING OF MONAZITE SAND

    Science.gov (United States)

    Calkins, G.D.; Bohlmann, E.G.

    1957-12-01

    A process for the recovery of thorium, uranium, and rare earths from monazite sands is presented. The sands are first digested and dissolved in concentrated NaOH, and the solution is then diluted causing precipitation of uranium, thorium and rare earth hydroxides. The precipitate is collected and dissolved in HCl, and the pH of this solution is adjusted to about 6, precipitating the hydroxides of thorium and uranium but leaving the rare earths in solution. The rare earths are then separated from the solution by precipitation at a still higher pH. The thorium and uranium containing precipitate is redissolved in HNO/sub 3/ and the two elements are separated by extraction into tributyl phosphate and back extraction with a weakly acidic solution to remove the thorium.

  11. Lack of effect on blood lipid and calcium concentrations of young men on changing from white to wholemeal bread.

    Science.gov (United States)

    Heaton, K W; Manning, A P; Hartog, M

    1976-01-01

    1. When nineteen "free-living" male students, who normally ate 231 (SEM 14) g white bread/d changed to wholemeal bread for a 19-week period, there was no significant change in body-weight, plasma cholesterol or plasma triglyceride levels. These values, as well as plasma concentrations of calcium, phosphate, urate and haemoglobin, remained essentially the same as those for a control group. 2. Increasing the wheat-fibre intake by eating wholemeal bread is not an effective method for reducing blood lipids levels, at least in healthy young men with a moderate bread intake.

  12. Lack of effect of cimetidine on the pharmacokinetics and metabolism of a single oral dose of metronidazole

    DEFF Research Database (Denmark)

    Loft, S; Døssing, M; Sonne, J

    1988-01-01

    The time course of the effect of cimetidine on the pharmacokinetics of metronidazole was investigated in 6 healthy volunteers. Cimetidine 1.0 g/day was administered for 9-days and metronidazole 500 mg was administered orally on the second and eighth days, and in a control experiment. During...... cimetidine treatment the plasma kinetics of metronidazole and its partial clearance by renal excretion of the unchanged compound, glucuronidation, hydroxylation and oxidation to its acetic acid metabolite were not significantly different from the control values. The results indicate that cimetidine does...

  13. Lack of enhanced effect of a chlorine dioxide-based cleaning regimen on environmental contamination with Clostridium difficile spores.

    Science.gov (United States)

    Goldenberg, S D; Patel, A; Tucker, D; French, G L

    2012-09-01

    Spores of Clostridium difficile may play a significant role in transmission of disease within the healthcare environment and are resistant to a variety of detergents and cleaning fluids. A range of environmental cleaning agents has recently become available, many of which claim to be sporicidal. We investigated the effect of changing to a chlorine dioxide-based cleaning regimen on C. difficile environmental contamination and patient infection rates. The prevalence of environmental contamination was unaffected with a rate of 8% (9/120) before and 8% (17/212) following the change. Rates of patient infection were also unchanged during these periods.

  14. Trajectories of saltating sand particles behind a porous fence

    Science.gov (United States)

    Zhang, Ning; Lee, Sang Joon; Chen, Ting-Guo

    2015-01-01

    Trajectories of aeolian sand particles behind a porous wind fence embedded in a simulated atmospheric boundary layer were visualized experimentally, to investigate the shelter effect of the fence on sand saltation. Two sand samples, one collected from a beach (d = 250 μm) and the other from a desert (d = 100 μm), were tested in comparison with the previous studies of a 'no-fence' case. A wind fence (ε = 38.5%) was installed on a flat sand bed filled with each sand sample. A high-speed photography technique and the particle tracking velocimetry (PTV) method were employed to reconstruct the trajectories of particles saltating behind the fence. The collision processes of these sand particles were analyzed, momentum and kinetic energy transfer between saltating particles and ground surface were also investigated. In the wake region, probability density distributions of the impact velocities agree well with the pattern of no-fence case, and can be explained by a log-normal law. The horizontal component of impact velocity for the beach sand is decreased by about 54%, and about 76% for the desert sand. Vertical restitution coefficients of bouncing particles are smaller than 1.0 due to the presence of the wind fence. The saltating particles lose a large proportion of their energy during the collision process. These results illustrate that the porous wind fence effectively abates the further evolution of saltating sand particles.

  15. Lack of insecticidal effect of mosquito coils containing either metofluthrin or esbiothrin on Anopheles gambiae sensu lato mosquitoes.

    Science.gov (United States)

    Lukwa, Nzira; Chiwade, Tonderai

    2008-12-01

    Use of mosquito coils for personal protection against malaria and mosquito nuisance is advocated under mosquito and malaria control programmes. We performed field studies of mosquito coils containing either metofluthrin or esbiothrin in experimental huts situated in Kamhororo village, Gokwe district, Zimbabwe. All tests were performed on 3-5 day old reared female Anopheles gambiae sensu lato mosquitoes. The burning times were 9hr 20min for mosquito coils containing metofluthrin and 8 hr for those containing esbiothrin and the results were significantly different (p = metofluthrin was 90% and that for esbiothrin was 73.3% and the results were significantly different (p = 0.00). Mosquito coils containing metofluthrin had a mean repellence of 92.7% as compared to 85.4% for esbiothrin and the results were not significantly different (p=0.27). The protection time as required by EPA (1999) was 6 hr for mosquito coils containing metofluthrin and 5 hr for those containing esbiothrin. The mean insecticidal effect of mosquito coils containing metofluthrin was 84% as compared to 83% for those containing esbiothrin and the results were not significantly different (p = 0.56). Both mosquito formulations could not be classified as having insecticidal effect since none of them met the 95% mortality rate criteria.

  16. Lack of effects of GHB precursors GBL and 1,4-BD following i.c.v. administration in rats.

    Science.gov (United States)

    Carter, Lawrence P; Koek, Wouter; France, Charles P

    2006-11-01

    Gamma-hydroxybutyrate (GHB) is used therapeutically and recreationally worldwide. Since the scheduling of GHB by the USA and the United Nations in 2000-2001, the recreational use of GHB precursors has reportedly increased. The aim of this study was to examine if potency differences of GHB and GHB-like compounds are due to their blood-brain barrier permeability. The effects of peripheral and central administration of GHB, GHB precursors gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), and the gamma-aminobutyric acid (GABA)(B) receptor agonist baclofen on schedule-controlled responding were examined in rats. GHB and baclofen were 276- and 253-fold more potent, respectively, after intracerebroventricular (i.c.v.) administration than after intraperitoneal (i.p.) administration, whereas GBL and 1,4-BD, up to a dose of 1780 microg were without effect after i.c.v. administration. These data suggest that GBL and 1,4-BD are not metabolically converted to GHB in the brain, that enhanced brain penetration cannot account for potency differences between compounds, and that baclofen, like GHB, can readily cross the blood-brain barrier.

  17. Moving sand dunes

    CERN Document Server

    Sparavigna, Amelia Carolina

    2011-01-01

    In several desert areas, the slow motion of sand dunes can be a challenge for modern human activities and a threat for the survival of ancient places or archaeological sites. However, several methods exist for surveying the dune fields and estimate their migration rate. Among these methods, the use of satellite images, in particular of those freely available on the World Wide Web, is a convenient resource for the planning of future human settlements and activities.

  18. Effects of oil pollution at Kuwait's Greater Al-Burgan oil field on the timing of morning emergence, basking and foraging behaviors by the sand lizard Acanthodactylus scutellatus.

    Science.gov (United States)

    Al-Hashem, M Abdulla; Brain, P F; Omar, S Ahmad

    2008-02-15

    An attempt was made to study the effects of oil pollution in a desert location (the Greater Al-Burgan oil fields, an area damaged in the second Gulf War) in Kuwait on the behaviour of the Sand lizard A. scutellatus. Polluted sites with apparently different degrees of contamination (namely tar mat, soot and clear sites) were compared with control areas outside this region. Between 2002 and 2003, ten lizards (5 of each sex) on each polluted and each control site were observed in the field at a time of the year when they were highly active. Air, substrate and burrow temperatures were recorded and lizards were monitored for their morning emergence times, as well as their basking and foraging activities. The present study confirmed that the morning emergence times and the basking behavior varied in sand lizards among the different pollution site categories. Physical changes in the tar mat sites caused the substrate temperatures in these locations to rise more quickly in the morning in response to solar gain than was the case in the other sites. This gives lizards in these locations the opportunity to emerge earlier and to start eating more quickly, giving them an energetic advantage (perhaps, in turn, influencing their rates of growth and fecundity). The clear sites had the next earliest emergence and were the next hottest but it is difficult to account for this in terms of the physical characteristics of this site. The basking times were clearly shorter on the dark soot and tar mat sites that appeared to have higher solar gain than control or clear sites. There did not appear to be any obvious differences in foraging activity of lizards in the different locations. It appears that some aspects of simple behaviour in these lizards provides a reliable, noninvasive indices for assessing oil pollution in desert locations. The precise impact of these changes in these reptiles on their long-term viability needs to be evaluated.

  19. Lack of influence of dyspareunia on the beneficial effect of intravaginal prasterone (dehydroepiandrosterone, DHEA) on sexual dysfunction in postmenopausal women.

    Science.gov (United States)

    Labrie, Fernand; Archer, David; Bouchard, Céline; Fortier, Michel; Cusan, Leonello; Gomez, José-Luis; Girard, Ginette; Baron, Mira; Ayotte, Normand; Moreau, Michèle; Dubé, Robert; Côté, Isabelle; Labrie, Claude; Lavoie, Lyne; Gilbert, Lucy; Martel, Céline; Balser, John

    2014-07-01

    We have previously observed that intravaginal prasterone (dehydroepiandrosterone, DHEA) improved all domains of female sexual dysfunction (FSD). Investigate the influence of moderate/severe pain at sexual activity (dyspareunia) (MSD) at baseline on FSD following prasterone administration. The effect of daily administration of prasterone (0, 3.25 mg, 6.5 mg or 13 mg) for 12 weeks on FSD in 215 postmenopausal women with or without MSD at baseline was evaluated in a prospective, randomized, double-blind, and placebo-controlled phase III clinical trial. Differences were examined on desire, arousal and orgasm. Comparable benefits were observed in women not having MSD (n = 56) vs. those having MSD (n = 159). The benefits over placebo in prasterone-treated women for desire, avoiding intimacy and vaginal dryness as well as for the total sexual domain of the MENQOL (Menopause Specific Quality of Life) questionnaire, ranged between 18.0% and 38.2% with P values of <0.05 or <0.01 except in one out of 12 subgroups. For the arousal/sensation, arousal/lubrication and summary score of the ASF (Abbreviated Sexual Function) questionnaire, in the MSD+ group, improvements of 64.2% (P = 0.01), 118% (P = 0.001) and 31.1% (P = 0.03) were observed over placebo, respectively, while similar differences (58.0%, 67.6% and 32.1%) did not reach statistical significance in the MSD- group having up to only 44 prasterone-treated women compared with 119 in the MSD+ group. No MSD at baseline does not apparently affect the effects of intravaginal prasterone on sexual dysfunction. Knowing the absence of significant effects of estrogens on FSD, the present data suggest that vulvovaginal atrophy (VVA) and vulvovaginal sexual dysfunction (VVSD) are two different consequences of sex steroid deficiency at menopause which can respond independently. In addition, the present data seriously question the justification of pain being part of FSD as well as the separation of FSD into

  20. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius;

    2008-01-01

    Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation...... cementation is derived from internal sources. Rather, in spite of large variation in porosity and quartz cement content, a regular pattern of porosity decrease is related to increasing temperature or depth. The observed heterogeneity is due to local factors that influence the precipitation of quartz cement......, including sandstone architecture, i.e., distribution of shales within the sandstone bodies, and sandstone thickness. Heterogeneity is inherent to sandstone architecture and to the fact that silica for quartz cementation is derived from heterogeneously distributed local pressure solution. Models predicting...

  1. Accumulation of selenium and lack of severe effects on productivity of American dippers (Cinclus mexicanus) and spotted sandpipers (Actitis macularia).

    Science.gov (United States)

    Harding, Lee E; Graham, Mark; Paton, Dale

    2005-04-01

    Selenium has been found at elevated concentrations in water, sediments, and aquatic biota in the Elk River (British Columbia, Canada) and some of its tributaries downstream of several coal mines. Selenium water concentrations in those areas exceed Canadian and British Columbia guidelines and are above levels at which adverse effects to fish and waterfowl could occur. We compared selenium concentrations in the eggs of two riverine waterbirds, American dippers and spotted sandpipers, with measures of productivity: the number of eggs laid, egg hatchability, and nestling survival. In American dippers, the mean egg selenium concentration from the exposed areas, 1.10 +/- SE 0.059 microg/g wet weight, was indistinguishable from the reference areas, 0.96 +/- SE 0.059 microg/g wet weight. For spotted sandpipers, the mean egg selenium concentration in the exposed areas, 2.2 +/- 0.5 microg/g wet weight, was significantly higher than in the reference areas, 1.2 +/- 0.14 microg/g wet weight, but less than reported thresholds for waterfowl and other shorebirds. There were no significant differences in egg hatchability between dippers in reference and exposed areas, but reduced hatchability was apparent for sandpipers in exposed locations. Despite the slightly reduced hatchability in sandpipers, overall productivity was higher than regional norms for both species; thus, selenium did not affect the number of young recruited to local populations. We did not observe teratogenic effects in either species, although none was expected at these concentrations. Despite moderately high selenium concentrations in the water, mean egg selenium concentrations were less than predicted from uptake models. We hypothesise that the relatively low uptake of selenium into the eggs of the two waterbirds in this study is likely due to their lotic environment's low biological transformation and uptake rates.

  2. Lack of a protective effect of menhaden oil on skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate.

    Science.gov (United States)

    Locniskar, M; Belury, M A; Cumberland, A G; Patrick, K E; Fischer, S M

    1990-09-01

    Fish oil has been shown to have a protective effect in some cancer models. To determine whether fish oil alters skin tumorigenesis, a study was designed using the initiation-promotion mouse skin carcinogenesis model, feeding mice during the promotion stage a constant overall amount of dietary fat (10%) in which the levels of menhaden oil (MO) varied from 0 to 8.5% or corn oil (CO) at 10%. SENCAR mice were initiated with 10 nmol dimethylbenz[a]anthracene. Two weeks later mice were divided into five groups and maintained on one of the following AIN-76 based diets consisting of: 8.5% coconut oil (CT)/1.5% CO (diet A); 1% MO/7.5% CT/1.5% CO (diet B); 4% MO/4.5% CT/1.5% CO (diet C); 8.5% MO/1.5% CO (diet D); or 10% CO (diet E). Two weeks later, promotion with twice weekly applications of 1 micrograms 12-O-tetradecanoylphorbol-13-acetate (TPA) was begun and continued for 24 weeks. No statistically significant differences in kcal food consumed or body wts were observed between diet groups during the study. The final papilloma and carcinoma incidence was not different among the diet groups. However, differences were seen in the rate of papilloma appearance with the group fed diet E (10% CO) being the slowest and diet B being the most rapid. In a parallel study, ornithine decarboxylase activity, a suggested marker of promotion, was greatly elevated in the epidermis of all TPA-treated mice and the effect of diet tended to reflect the different rates of tumor formation observed among the groups. These data indicate that the diets containing fish oil were not protective in the final incidence of tumor formation and suggest that a better understanding of the complex interactions is warranted before recommendations are made to alter the human diet for cancer prevention.

  3. Lack of effect on sexual behaviour or the development of testicular function after removal of olfactory bulbs in prepubertal boars.

    Science.gov (United States)

    Booth, W D; Baldwin, B A

    1980-01-01

    Bilateral olfactory bulb ablation was carried out surgically on 8 prepubertal Large White boars when they were 10-12 weeks of age. Between 26 weeks and slaughter at 47-49 weeks of age, androgen was determined in peripheral blood plasma of bulbectomized and unoperated control animals. The pigs were exposed to oestrous female pigs to observe mating behaviour, and to alien boars to observe aggressive behaviour. Saliva produced during behaviour tests was extracted with diethyl ether and levels of the pheromonal 16-androstene steroids in the extracts were determined by a colorimetric assay. After slaughter the testes, accessory organs and submaxillary glands were weighed, and pices of tissue together with olfactory epithelium were processed for light microscopy; fructose and zinc were determined in the seminal vesicles. The results showed that, contrary to findings in some rodents, prepubertal bilateral bulbectomy in the male pig had no significant effect on mating or aggressive behaviour, or testicular function in so far as complete spermatogenesis was present and normal levels of androgen and pheromone were maintained together with the integrity of the accessory organs. However, in keeping with findings in other species, the height of the olfactory epithelium was generally reduced in the bulbectomized pigs.

  4. The Importance of Agriculture-Dominated Landscapes and Lack of Field Border Effect for Early-Succession Songbird Nest Success

    Directory of Open Access Journals (Sweden)

    Jason D. Riddle

    2010-12-01

    Full Text Available In recent decades, many early-succession songbird species have experienced severe and widespread declines, which often are related to habitat destruction. Field borders create additional or enhance existing early-succession habitat on farmland. However, field border shape and the landscape context surrounding farms may influence the effectiveness of field borders in contributing to the stabilization or increase of early-succession bird populations. We examined the influence of linear and nonlinear field borders on farms in landscapes dominated by either agriculture or forests on nest success and Brown-headed Cowbird (Molothrus ater brood parasitism of Indigo Bunting (Passerina cyanea and Blue Grosbeak (Passerina caerulea nests combined. Field border establishment did not affect nest survival probability and brood parasitism frequency of Indigo Bunting and Blue Grosbeak nests. Indigo Bunting/Blue Grosbeak nest success probability was more than twice as high in agriculture-dominated landscapes (39% than in forested landscapes (17%, and brood parasitism frequency was high (33% but did not differ between landscapes. Edges in agriculture-dominated landscapes can be higher-quality habitats for early-succession birds than edges in forest-dominated landscapes, but our field border treatments did not enhance nest success for these birds on farms in either landscape.

  5. Lack of effect of cell-wall targeted antibacterials on biofilm formation and antifungal susceptibility of Candidaspecies

    Directory of Open Access Journals (Sweden)

    Gisela Myrian de Lima Leite

    2014-09-01

    Full Text Available The use of central venous catheters (CVC and broad-spectrum antibacterials are among the main risk factors for the development of candidemia in patients admitted to intensive care units (ICU. It is known that some antibacterials increase the resistance of these yeasts to azole antifungals. Thus, the aim of this research was to determine whether yeast present in CVC colonizations previously exposed to cell-wall targeted antibacterials benefit from a reduction in susceptibility to fluconazole and voriconazole, facilitating their ability to form biofilms. Candida albicans, C. tropicalis, C. glabrata, C. parapsilosis and C. guilhermondii were seeded into antibacterial (cefepime, meropenem, vancomycin, and piperacillin-tazobactam gradient plates produced in Mueller-Hinton Agar. The susceptibility to fluconazole and voriconazole and the biofilm formation of the yeasts were tested before and after exposure to the antibacterials. None of the antibacterials exerted a significant effect on the in vitro susceptibility of the yeasts to the antifungal agents or on their ability to form biofilms. These results suggest that increased candidemia in ICU patients is not attributable to possible alterations in the yeasts, but is more likely caused by a weakening of the patient's general condition after long exposure to infection.

  6. Lack of meaningful effect of ridaforolimus on the pharmacokinetics of midazolam in cancer patients: model prediction and clinical confirmation.

    Science.gov (United States)

    Stroh, Mark; Talaty, Jennifer; Sandhu, Punam; McCrea, Jacqueline; Patnaik, Amita; Tolcher, Anthony; Palcza, John; Orford, Keith; Breidinger, Sheila; Narasimhan, Narayana; Panebianco, Deborah; Lush, Richard; Papadopoulos, Kyriakos P; Wagner, John A; Trucksis, Michele; Agrawal, Nancy

    2014-11-01

    Ridaforolimus, a unique non-prodrug analog of rapamycin, is a potent inhibitor of mTOR under development for cancer treatment. In vitro data suggest ridaforolimus is a reversible and time-dependent inhibitor of CYP3A. A model-based evaluation suggested an increase in midazolam area under the curve (AUC(0- ∞)) of between 1.13- and 1.25-fold in the presence of therapeutic concentrations of ridaforolimus. The pharmacokinetic interaction between multiple oral doses of ridaforolimus and a single oral dose of midazolam was evaluated in an open-label, fixed-sequence study, in which cancer patients received a single oral dose of 2 mg midazolam followed by 5 consecutive daily single oral doses of 40 mg ridaforolimus with a single dose of 2 mg midazolam with the fifth ridaforolimus dose. Changes in midazolam exposure were minimal [geometric mean ratios and 90% confidence intervals: 1.23 (1.07, 1.40) for AUC(0-∞) and 0.92 (0.82, 1.03) for maximum concentrations (C(max)), respectively]. Consistent with model predictions, ridaforolimus had no clinically important effect on midazolam pharmacokinetics and is not anticipated to be a perpetrator of drug-drug interactions (DDIs) when coadministered with CYP3A substrates. Model-based approaches can provide reasonable estimates of DDI liability, potentially obviating the need to conduct dedicated DDI studies especially in challenging populations like cancer patients.

  7. Long-term effects of controllability or the lack of it on coping abilities and stress resilience in the rat.

    Science.gov (United States)

    Lucas, Morgan; Ilin, Yana; Anunu, Rachel; Kehat, Orli; Xu, Lin; Desmedt, Aline; Richter-Levin, Gal

    2014-09-01

    Findings suggest that stress-induced impaired learning and coping abilities may be attributed more to the psychological nature of the stressor, rather than its physical properties. It has been proposed that establishing controllability over stressors can ameliorate some of its effects on cognition and behavior. Gaining controllability was suggested to be associated with the development of stress resilience. Based on repeated exposure to the two-way shuttle avoidance task, we previously developed and validated a behavioral task that leads to a strict dissociation between gaining controllability (to the level that the associated fear is significantly reduced) and a fearful state of uncontrollability. Employing this protocol, we investigated here the impact of gaining or failing to gain emotional controllability on indices of anxiety and depression and on subsequent abilities to cope with positively or negatively reinforcing learning experiences. In agreement with previous studies, rats exposed to the uncontrollable protocol demonstrated high concentration of sera corticosterone, increased immobility, reduced duration of struggling in the forced swim test and impaired ability to acquire subsequent learning tasks. Achieving emotional controllability resulted in resilience to stress as was indicated by longer duration of struggling in the forced swim test, and enhanced learning abilities. Our prolonged training protocol, with the demonstrated ability of rats to gain emotional controllability, is proposed as a useful tool to study the neurobiological mechanisms of stress resilience.

  8. A lack of consensus in the literature findings on the removal of airborne benzene by houseplants: Effect of bacterial enrichment

    Science.gov (United States)

    Sriprapat, Wararat; Strand, Stuart E.

    2016-04-01

    Removal rates of benzene and formaldehyde gas by houseplants reported by several laboratories varied by several orders of magnitude. We hypothesized that these variations were caused by differential responses of soil microbial populations to the high levels of pollutant used in the studies, and tested responses to benzene by plants and soils separately. Five houseplant species and tobacco were exposed to benzene under hydroponic conditions and the uptake rates compared. Among the test plants, Syngonium podophyllum and Chlorophytum comosum and Epipremnum aureum had the highest benzene removal rates. The effects of benzene addition on populations of soil bacteria were determined using reverse transcription quantitative PCR (RT-qPCR) assays targeting microbial genes involved in benzene degradation. The total bacterial population increased as shown by increases in the levels of eubacteria 16S rRNA, which was significantly higher in the high benzene incubations than in the low benzene incubations. Transcripts (mRNA) of genes encoding phenol monooxygenases, catechol-2,3-dioxygenase and the housekeeping gene rpoB increased in all soils incubated with high benzene concentrations. Therefore the enrichment of soils with benzene gas levels typical of experiments with houseplants in the literature artificially increased the levels of total soil bacterial populations, and especially the levels and activities of benzene-degrading bacteria.

  9. Lack of nano size effect on electrochemistry of dopamine at a gold nanoparticle modified indium tin oxide electrode

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Nanometer sized materials have been shown to possess excellent chemical and electrochemical catalytic properties.In this work,a gold nanoparticle (AuNP) modified indium tin oxide (ITO) electrode was employed for investigating its electro-catalytic property.AuNP was deposited on the 3-aminopropyltriethoxysilane (APTES) modified ITO electrode by self-assembly,and was characterized by scanning electron microscopy and cyclic voltammetry.Although the electrochemical reaction of dopamine was very sluggish on the ITO/APTES electrode,it was significantly enhanced after AuNP deposition.The cyclic voltammogram exhibited apparent dependence on the surface coverage of 11 nm AuNPs,which could be rationalized by different modes of mass diffusion.Among the different sizes of AuNP investigated,the lowest anodic peak potential was observed on 11 nm AuNP.However,the potential was still about 50 mV more positive than that obtained on a bulk gold electrode of similar geometry.It is therefore concluded that there is no nanometer size effect of AuNP modified ITO on the electrochemistry of dopamine.

  10. Scopolamine-induced amnesia in humans: lack of effects of the benzodiazepine receptor antagonist β-carboline ZK 93426.

    Science.gov (United States)

    Duka, T; Edelmann, V; Schütt, B; Dorow, R; Fichte, K

    1992-01-01

    It has been suggested from pharmacological studies in animals that ZK 93426 may improve memory and other cognitive processes in humans. Scopolamine has been used to model aspects of memory impairment. To test the effects of ZK 93426 alone and in combination with scopolamine, ZK 93426 (0.04 mg/kg) or vehicle (Intralipid R) was administered intravenously (i.v.) to normal controls, pre-treated with either scopolamine 0.5 mg administered subcutaneously (s.c.) or the same volume of saline. A visual (presentation of pictures) and a verbal (words list) memory test were applied. Both drugs on their own and in combination were found to be safe and well tolerated. ZK 93426 did not antagonize the scopolamine-induced impairment of acquisition of the words list. Scopolamine did not impair delayed recall of visual or verbal material. ZK 93426 alone improved performance in delayed recall of visual material presented after drug application, whereas it impaired performance in delayed recall of visual material presented before drug administration.

  11. Lack of negative effects of the biological control agent Duddingtonia flagrans on soil nematodes and other nematophagous fungi.

    Science.gov (United States)

    Saumell, C A; Fernández, A S; Echevarria, F; Gonçalves, I; Iglesias, L; Sagües, M F; Rodríguez, E M

    2016-11-01

    The possible environmental effects of the massive use of Duddingtonia flagrans for controlling sheep nematodes were evaluated in two regions. Non-supplemented faeces and faeces from sheep supplemented with D. flagrans were deposited three times on pasture plots and samples were collected 7 and 14 days post-deposition. Samples were cultured in agar-water (2%) with Panagrellus spp. to recover D. flagrans and other nematophagous fungi, and soil nematodes were extracted using Baermann funnels and counted. No significant differences in the populations of soil nematodes and fungi colonizing sheep faeces (P > 0.05) were observed between supplemented and non-supplemented groups, except in one sample. The topsoil in contact with the faeces was sampled 1-4 months post-deposition, revealing that, with one exception, D. flagrans did not persist in soil beyond 2 months post-deposition. Duddingtonia flagrans does not affect faecal colonization by other fungi and soil nematodes and, once deployed on pasture, does not survive for long periods in the environment.

  12. Isotopic studies in Pacific Panama mangrove estuaries reveal lack of effect of watershed deforestation on food webs.

    Science.gov (United States)

    Viana, Inés G; Valiela, Ivan; Martinetto, Paulina; Monteiro Pierce, Rita; Fox, Sophia E

    2015-02-01

    Stable isotopic N, C, and S in food webs of 8 mangrove estuaries on the Pacific coast of Panama were measured to 1) determine whether the degree of deforestation of tropical forests on the contributing watersheds was detectable within the estuarine food web, and 2) define external sources of the food webs within the mangrove estuaries. Even though terrestrial rain forest cover on the contributing watersheds differed between 23 and 92%, the effect of deforestation was not detectable on stable isotopic values in food webs present at the mouth of the receiving estuaries. We used stable isotopic measures to identify producers or organic sources that supported the estuarine food web. N isotopic values of consumers spanned a broad range, from about 2.7 to 12.3‰. Mean δ(15)N of primary producers and organic matter varied from 3.3 for macroalgae to 4.7‰ for suspended particulate matter and large particulate matter. The δ(13)C consumer data varied between -26 and -9‰, but isotopic values of the major apparent producers or organic matter sampled could not account for this range variability. The structure of the food web was clarified when we added literature isotopic values of microphytobenthos and coralline algae, suggesting that these, or other producers with similar isotopic signature, may be part of the food webs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Lack of genotoxic effects (micronucleus induction) in human lymphocytes exposed in vitro to 900 MHz electromagnetic fields.

    Science.gov (United States)

    Zeni, O; Chiavoni, A S; Sannino, A; Antolini, A; Forigo, D; Bersani, F; Scarfì, M R

    2003-08-01

    In the present study, we investigated the induction of genotoxic effects in human peripheral blood lymphocytes after exposure to electromagnetic fields used in mobile communication systems (frequency 900 MHz). For this purpose, the incidence of micronuclei was evaluated by applying the cytokinesis-block micronucleus assay. Cytotoxicity was also investigated using the cytokinesis-block proliferation index. The experiments were performed on peripheral blood from 20 healthy donors, and several conditions were tested by varying the duration of exposure, the specific absorption rate (SAR), and the signal [continuous-wave (CW) or GSM (Global System of Mobile Communication) modulated signal]. The following exposures were carried out: (1) CW intermittent exposure (SAR = 1.6 W/kg) for 6 min followed by a 3-h pause (14 on/off cycles); (2) GSM signal, intermittent exposure as described in (1); (3) GSM signal, intermittent exposure as described in (1) 24 h before stimulation with phytohemagglutinin (8 on/off cycles); (4) GSM signal, intermittent exposure (SAR = 0.2 W/kg) 1 h per day for 3 days. The SARs were estimated numerically. No statistically significant differences were detected in any case in terms of either micronucleus frequency or cell cycle kinetics.

  14. Bioaugmentation of flow-through sand filters

    DEFF Research Database (Denmark)

    Samuelsen, Elin Djurhuus

    Global applications of pesticides in agricultural production have led to the detection of trace amounts of pesticides in groundwater resources in levels exceeding the EU threshold limit for drinking water of 0.1 µg L-1. Pesticide-polluted groundwater may be remediated by inoculating waterworks sand...... filters with specific degrading bacteria. However, degradation efficiency is often hampered by poor adhesion and a lack of sustained catabolic activity of the introduced bacteria. The overall objective of this thesis was to investigate the significance of selected bacterial surface properties...... coincided with efficient mineralisation/degradation, and proposed the tfdC gene as a suitable marker for monitoring phenoxy acid degradation in strain PM2. Furthermore, when testing strain PM2s degradation performance in flow-through sand columns, we found that strain PM2 was able to sustain induced...

  15. Randomized Controlled Trials Evaluating Effect of Television Advertising on Food Intake in Children: Why Such a Sensitive Topic is Lacking Top-Level Evidence?

    Science.gov (United States)

    Gregori, Dario; Ballali, Simonetta; Vecchio, Maria Gabriella; Sciré, Antonella Silvia; Foltran, Francesca; Berchialla, Paola

    2014-01-01

    The aim of this study was to perform a systematic review of evidence coming from randomized controlled trials (RCT) aimed at assessing the effect of television advertising on food intake in children from 4 to 12 years old. Randomized controlled trials were searched in PubMed database and included if they assessed the effect of direct exposure to television food advertising over the actual energy intake of children. Seven studies out of 2166 fulfilled the inclusion criteria. The association between television advertising and energy intake is based on a very limited set of randomized researches lacking a solid ground of first-level evidence.

  16. Optimization of Enzyme-Mediated Calcite Precipitation as a Soil-Improvement Technique: The Effect of Aragonite and Gypsum on the Mechanical Properties of Treated Sand

    Directory of Open Access Journals (Sweden)

    Heriansyah Putra

    2017-02-01

    Full Text Available The effectiveness of magnesium as a substitute material in enzyme-mediated calcite precipitation was evaluated. Magnesium sulfate was added to the injecting solution composed of urea, urease, and calcium chloride. The effect of the substitution on the amount of precipitated materials was evaluated through precipitation tests. X-ray powder diffraction and scanning electron microscopy analyses were conducted to examine the mineralogical morphology of the precipitated minerals and to determine the effect of magnesium on the composition of the precipitated materials. In addition to calcite, aragonite and gypsum were formed as the precipitated materials. The effect of the presence of aragonite and gypsum, in addition to calcite, as a soil-improvement technique was evaluated through unconfined compressive strength tests. Soil specimens were prepared in polyvinyl chloride cylinders and treated with concentration-controlled solutions, which produced calcite, aragonite, and gypsum. The mineralogical analysis revealed that the low and high concentrations of magnesium sulfate effectively promoted the formation of aragonite and gypsum, respectively. The injecting solutions which produced aragonite and calcite brought about a significant improvement in soil strength. The presence of the precipitated materials, comprising 10% of the soil mass within a treated sand, generated a strength of 0.6 MPa.

  17. Behavioral explanations underlying the lack of trap effectiveness for small-scale management of Japanese beetles (Coleoptera: Scarabaeidae).

    Science.gov (United States)

    Switzer, Paul V; Enstrom, Patrick C; Schoenick, Carissa A

    2009-06-01

    Traps containing a combination floral and synthetic pheromone lure are used to monitor and manage Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae). One key factor limiting trap effectiveness for beetle control is the "trap spillover" phenomenon, in which the trap attracts beetles without capturing them, resulting in increased damage to surrounding host plants. We investigated the mechanisms underlying trap spillover by conducting two studies in a soybean field in east central Illinois. In the first study, we set up trap stations for 1 d and compared the sex, size, and egg load (for females) of beetles caught in the traps with those on the plants immediately surrounding the trap, downwind of the trap, at lure-only (no trap) stations, and at control areas. Females caught in traps tended to be smaller than those on plants surrounding the traps, and females attracted to the traps had fewer eggs than those downwind or at control sites. We did not find any difference in male characteristics. In the second study, we observed the behavior of beetles initially approaching traps. Upon initial approach, the majority of individuals landed on plants before making contact with the trap, and those beetles that spent an extended time on the leaves tended to be females. Arriving males would occasionally pair with these females on the plants. Overall, traps did not capture a random subset of the beetles present in the field. We hypothesize that trap spillover is a result of arriving females not being as attracted to the precise location of the trap as they are to the general location itself, and of arriving males seeking mates and finding them among these spillover females.

  18. Accumulation of selenium and lack of severe effects on productivity of American dippers (Cinclus mexicanus) and spotted sandpipers (Actitis macularia)

    Energy Technology Data Exchange (ETDEWEB)

    Harding, L.E.; Graham, M.; Paton, D. [SciWrite Environmental Science Ltd, Coquitlam, BC (Canada)

    2005-04-01

    Selenium has been found at elevated concentrations in water, sediments, and aquatic biota in the Elk River (British Columbia, Canada) and some of its tributaries downstream of several coal mines. Selenium water concentrations in those areas are above levels at which adverse effects to fish and waterfowl could occur. We compared selenium concentrations in the eggs of two riverine waterbirds, American dippers and spotted sandpipers, with measures of productivity: the number of eggs laid, egg hatchability, and nestling Survival. In American dippers, the mean egg selenium concentration from the exposed areas, 1.10 {+-} SE 0.059 {mu}g/g wet weight, was indistinguishable from the reference areas, 0.96 {+-} SE 0.059 {mu} g/g wet weight. For spotted sandpipers, the mean egg selenium concentration in the exposed areas, 2.2 {+-} 0.5 {mu} g/g wet weight, was significantly higher than in the reference areas, 1.2 {+-} 0.14 {mu} g/g wet weight, but less than reported thresholds for waterfowl and other shorebirds. There were no significant differences in egg hatchability between dippers in reference and exposed areas, but reduced hatchability was apparent for sandpipers in exposed locations. Despite the slightly reduced hatchability in sandpipers, overall productivity was higher than regional norms for both species; thus, selenium did not affect the number of young recruited to local populations. Despite moderately high selenium concentrations in the water, mean egg selenium concentrations were less than predicted from uptake models. We hypothesise that the relatively low uptake of selenium into the eggs of the two waterbirds in this study is likely due to their lotic environment's low biological transformation and uptake rates.

  19. Provenance of coastal dune sands along Red Sea, Egypt

    Indian Academy of Sciences (India)

    Samir M Zaid

    2017-06-01

    Texture, mineralogy, and major and trace element geochemistry of 26 coastal dune sand samples were studied to determine the provenance and tectonic environment of two dune fields close to the beaches of Safaga (SF) and Quseir (QS) at the Egyptian Red Sea coast. Onshore winds generate fine, moderate, moderately-well to well-sorted, coarse-skewed to near-symmetrical dune sands with mesokurtic distributions. Winds pick up and transport grains from nearby beach sands and alluvial deposits into a wide Red Sea coastal plain at the border of the beach. The mineralogical (Qt–Ft–Lt) and geochemical composition of the sands, indicate that SF and QS coastal dune sands are mature and influenced by quartz-rich sands. The average CIA values in SF and QS coastal dune sands are low relative to the range of the PAAS, suggesting an arid climate and a low intensity of chemical weathering. The SF and QS coastal dune sand samples are plotted in the recycled orogen and partly in craton interior fields suggesting recycled older sedimentary and partly metamorphic-plutonic sources. The high content of quartz with shell debris and carbonates in coastal dune sands support the recycled sedimentary beach and alluvial sand sources. The dominance of heavy minerals like amphiboles (hornblende) and biotite in the coastal dune sands also supports the effect of metamorphic-plutonic source rocks. The new tectonic discriminant-function diagrams suggest that the coastal dune sands were deposited in a passive margin of a synrift basin. The results provide a good evidence for the extension in the Red Sea rift system during Oligocene-post Pliocene, which is consistent with the general geology of Egypt.

  20. Posaconazole tablet pharmacokinetics: lack of effect of concomitant medications altering gastric pH and gastric motility in healthy subjects.

    Science.gov (United States)

    Kraft, Walter K; Chang, Peter S; van Iersel, Marlou L P S; Waskin, Hetty; Krishna, Gopal; Kersemaekers, Wendy M

    2014-07-01

    Posaconazole oral suspension is an extended-spectrum triazole that should be taken with food to maximize absorption. A new posaconazole tablet formulation has demonstrated improved bioavailability over the oral suspension in healthy adults in a fasting state. This study evaluated the effects of concomitant medications altering gastric pH (antacid, ranitidine, and esomeprazole) and gastric motility (metoclopramide) on the pharmacokinetics of posaconazole tablets. This was a prospective open-label 5-way crossover study in 20 healthy volunteers. In each treatment period, a single 400-mg dose (4 100-mg tablets) of posaconazole was administered alone or with 20 ml antacid (2 g of aluminum hydroxide and 2 g of magnesium hydroxide), ranitidine (150 mg), esomeprazole (40 mg), or metoclopramide (15 mg). There was a ≥ 10-day washout between treatment periods. Posaconazole exposure, time to maximum concentration of drug in serum (Tmax), and apparent terminal half-life (t1/2) were similar when posaconazole was administered alone or with medications affecting gastric pH and gastric motility. Geometric mean ratios (90% confidence intervals [CIs]) of the area under the concentration-time curve from time zero to infinity (AUC0-inf) (posaconazole with medications affecting gastric pH and gastric motility versus posaconazole alone) were 1.03 (0.88-1.20) with antacid, 0.97 (0.84-1.12) with ranitidine, 1.01 (0.87-1.17) with esomeprazole, and 0.93 (0.79-1.09) with metoclopramide. Geometric mean ratios (90% CIs) of the maximum concentration of drug in serum (Cmax) were 1.06 (0.90-1.26) with antacid, 1.04 (0.88-1.23) with ranitidine, 1.05 (0.89-1.24) with esomeprazole, and 0.86 (0.73-1.02) with metoclopramide. In summary, in healthy volunteers, the pharmacokinetics of a single 400-mg dose of posaconazole tablets was not altered to a clinically meaningful extent when posaconazole was administered alone or with medications affecting gastric pH or gastric motility.

  1. Lack of Effectiveness of Antiretroviral Therapy in Preventing HIV Infection in Serodiscordant Couples in Uganda: An Observational Study.

    Directory of Open Access Journals (Sweden)

    Josephine Birungi

    Full Text Available We examined the real-world effectiveness of ART as an HIV prevention tool among HIV serodiscordant couples in a programmatic setting in a low-income country.We enrolled individuals from HIV serodiscordant couples aged ≥18 years of age in Jinja, Uganda from June 2009 - June 2011. In one group of couples the HIV positive partner was receiving ART as they met clinical eligibility criteria (a CD4 cell count ≤250 cells/ μL or WHO Stage III/IV disease. In the second group the infected partner was not yet ART-eligible. We measured HIV incidence by testing the uninfected partner every three months. We conducted genetic linkage studies to determine the source of new infections in seroconverting participants.A total of 586 couples were enrolled of which 249 (42% of the HIV positive participants were receiving ART at enrollment, and an additional 99 (17% initiated ART during the study. The median duration of follow-up was 1.5 years. We found 9 new infections among partners of participants who had been receiving ART for at least three months and 8 new infections in partners of participants who had not received ART or received it for less than three months, for incidence rates of 2.09 per 100 person-years (PYRs and 2.30 per 100 PYRs, respectively. The incidence rate ratio for ART-use was 0.91 (95% confidence interval 0.31-2.70; p=0.999. The hazard ratio for HIV seroconversion associated with ART-use by the positive partner was 1.07 (95% CI 0.41-2.80. A total of 5/7 (71% of the transmissions on ART and 6/7 (86% of those not on ART were genetically linked.Overall HIV incidence was low in comparison to previous studies of serodiscordant couples. However, ART-use was not associated with a reduced risk of HIV transmission in this study.

  2. A new low-cost method of reclaiming mixed foundry waste sand based on wet-thermal composite reclamation

    Institute of Scientific and Technical Information of China (English)

    Fan Zitian; Liu Fuchu; Long Wei; Li Guona

    2014-01-01

    A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a great realistic significance. In the study to investigate the possibility of reusing two types of waste foundry sands, resin bonded sand and clay bonded sand which came from a Chinese casting factory, a new low-cost reclamation method of the mixed foundry waste sand based on the wet-thermal composite reclamation was proposed. The waste resin bonded sand was first reclaimed by a thermal method and the waste clay bonded sand was reclaimed by a wet method. Then, hot thermal reclaimed sand and the dehydrated wet reclaimed sand were mixed in certain proportions so that the hot thermal reclaimed sand dried the wet reclaimed sand leaving some water. The thermal reclamation efficiency of the waste resin bonded sand was researched at different heat levels. The optimized wet reclamation process of the waste clay bonded sand was achieved by investigating the effects of wet reclamation times, sand-water ratio and pH value on the reclaimed sand characteristics. The composite reclamation cost also was calculated. The research results showed that the properties of the mixed reclaimed sand can satisfy the application requirements of foundries; in which the temperature of the thermal reclamation waste resin bonded sand needs to be about 800 ºC, the number of cycles of wet reclamation waste clay bonded sand should reach four to five, the optimal sand-water ratio of wet reclamation is around 1:1.5, and the pH value should be adjusted by adding acid. The mass ratio of hot thermal reclaimed sand to dehydrated wet reclaimed sand is about 1:2.5, and the composite reclaimed sand cost is around 100 yuan RMB per ton.

  3. A new low-cost method of reclaiming mixed foundry waste sand based on wet-thermal composite reclamation

    Directory of Open Access Journals (Sweden)

    Fan Zitian

    2014-09-01

    Full Text Available A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a great realistic significance. In the study to investigate the possibility of reusing two types of waste foundry sands, resin bonded sand and clay bonded sand which came from a Chinese casting factory, a new low-cost reclamation method of the mixed foundry waste sand based on the wet-thermal composite reclamation was proposed. The waste resin bonded sand was first reclaimed by a thermal method and the waste clay bonded sand was reclaimed by a wet method. Then, hot thermal reclaimed sand and the dehydrated wet reclaimed sand were mixed in certain proportions so that the hot thermal reclaimed sand dried the wet reclaimed sand leaving some water. The thermal reclamation efficiency of the waste resin bonded sand was researched at different heat levels. The optimized wet reclamation process of the waste clay bonded sand was achieved by investigating the effects of wet reclamation times, sand-water ratio and pH value on the reclaimed sand characteristics. The composite reclamation cost also was calculated. The research results showed that the properties of the mixed reclaimed sand can satisfy the application requirements of foundries; in which the temperature of the thermal reclamation waste resin bonded sand needs to be about 800 篊, the number of cycles of wet reclamation waste clay bonded sand should reach four to five, the optimal sand-water ratio of wet reclamation is around 1:1.5, and the pH value should be adjusted by adding acid. The mass ratio of hot thermal reclaimed sand to dehydrated wet reclaimed sand is about 1:2.5, and the composite reclaimed sand cost is around 100 yuan RMB per ton.

  4. The technique of sand control with expandable screens

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, P. [Petrochina, Liaohe (China). Liaohe Oilfield Co.

    2009-07-01

    Sand production in heavy oil reservoirs can limit the normal production of oil wells. In this study, expandable screens were used as a sand control mechanism by filtering the sand as it entered the wellbore. The screen systems consists of an expandable outer housing, an expandable base pipe and a filtering layer. The screen expands radially through an expandable cone and presses into the casing well. Axial tension is used to shrink the screens radially through a fishing anchor in order to remove them from the well. The lack of a sand ring between the screen and the casing increases the flow area of the oil and reduces flow resistance caused by fine silt blockages. A series of laboratory experiments were conducted to study the expansion and shrinkage properties of the screens. A field test conducted at a well located in the Liaohe oilfield in China demonstrated that good sand control results can be obtained without the need for pump checking. It was concluded that the sand control method is easy to use and provides good sand control results in large open flow areas. 2 refs., 2 tabs., 3 figs.

  5. Sediment mathematical model for sand ridges and sand waves

    Institute of Scientific and Technical Information of China (English)

    LI Daming; WANG Xiao; WANG Xin; LI Yangyang

    2016-01-01

    A new theoretical model is formulated to describe internal movement mechanisms of the sand ridges and sand waves based on the momentum equation of a solid-liquid two-phase flow under a shear flow. Coupling this equation with two-dimensional shallow water equations and wave reflection-diffraction equation of mild slope, a two-dimensional coupling model is established and a validation is carried out by observed hydrogeology, tides, waves and sediment. The numerical results are compared with available observations. Satisfactory agreements are achieved. This coupling model is then applied to the Dongfang 1-1 Gas Field area to quantitatively predict the movement and evolution of submarine sand ridges and sand waves. As a result, it is found that the sand ridges and sand waves movement distance increases year by year, but the development trend is stable.

  6. Sand transport processes in the surf and swash zones

    NARCIS (Netherlands)

    Zanden, van der Joep

    2016-01-01

    Long-term predictions of beach morphology using numerical models contribute to cost-effective coastal protection strategies. The physics of sand transport in the wave breaking region and the swash zone are not fully understood, leading to poor predictive capability of existing sand transport models

  7. Effects of two Asian sand dusts transported from the dust source regions of Inner Mongolia and northeast China on murine lung eosinophilia

    Energy Technology Data Exchange (ETDEWEB)

    He, Miao, E-mail: hemiao.cmu@gmail.com [Environment and Chronic Non-communicable Disease Research Center, College of Public Health, China Medical University, 11001 Shenyang (China); Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Ichinose, Takamichi, E-mail: ichinose@oita-nhs.ac.jp [Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Song, Yuan, E-mail: freude@med.uoeh-u.ac.jp [Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahata-nishi-ku, Kitakyushu, 807-8555 Fukuoka (Japan); Yoshida, Yasuhiro, E-mail: songyuan1107@163.com [Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahata-nishi-ku, Kitakyushu, 807-8555 Fukuoka (Japan); Arashidani, Keiichi, E-mail: arashi@snow.ocn.ne.jp [Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahata-nishi-ku, Kitakyushu, 807-8555 Fukuoka (Japan); Yoshida, Seiichi, E-mail: syoshida@oita-nhs.ac.jp [Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Liu, Boying, E-mail: boyingliu321@gmail.com [Environment and Chronic Non-communicable Disease Research Center, College of Public Health, China Medical University, 11001 Shenyang (China); Department of Health Sciences, Oita University of Nursing and Health Sciences, 870-1201 Oita (Japan); Nishikawa, Masataka, E-mail: mnishi@nies.go.jp [Environmental Chemistry Division, National Institute for Environmental Studies, 305-8506 Tsukuba, Ibaraki (Japan); Takano, Hirohisa, E-mail: htakano@health.env.kyoto-u.ac.jp [Environmental Health Division, Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8530 (Japan); and others

    2013-11-01

    The quality and quantity of toxic materials adsorbed onto Asian sand dust (ASD) are different based on dust source regions and passage routes. The aggravating effects of two ASDs (ASD1 and ASD2) transported from the source regions of Inner Mongolia and northeast China on lung eosinophilia were compared to clarify the role of toxic materials in ASD. The ASDs contained different amounts of lipopolysaccharides (LPS) and β-glucan (ASD1 < ASD2) and SiO{sub 2} (ASD1 > ASD2). CD-1 mice were instilled intratracheally with ASD1, ASD2 and/or ovalbumin (OVA) four times at 2-week intervals. ASD1 and ASD2 enhanced eosinophil recruitment induced by OVA in the submucosa of the airway, with goblet cell proliferation in the bronchial epithelium. ASD1 and ASD2 synergistically increased OVA-induced eosinophil-relevant cytokines interleukin-5 (IL-5), IL-13 (ASD1 < ASD2) and chemokine eotaxin (ASD1 > ASD2) in bronchoalveolar lavage fluid. ASD2 aggravating effects on lung eosinophilia were greater than ASD1. The role of LPS and β-glucan in ASD2 on the production of pro-inflammatory mediators was assessed using in vitro bone marrow-derived macrophages (BMDMs) from wild type, Toll-like receptor 2-deficient (TLR2 −/−), TLR4 −/−, and MyD88 −/− mice (on Balb/c background). ASD2-stimulated TLR2 −/− BMDMs enhanced IL-6, IL-12, TNF-α, MCP-1 and MIP-1α secretion compared with ASD2-stimulated TLR4 −/− BMDMs. Protein expression from ASD2-stimulated MyD88 −/− BMDM were very low or undetectable. The in vitro results indicate that lung eosinophilia caused by ASD is TLR4 dependent. Therefore, the aggravation of OVA-related lung eosinophilia by ASD may be dependent on toxic substances derived from microbes, such as LPS, rather than SiO{sub 2}. - Highlights: • Asian sand dust (ASD) from the deserts of China causes serious respiratory problems. • The aggravating effects of two ASDs on lung eosinophilia were compared. • The ASDs contained different LPS and β-glucan (ASD1

  8. Faecal indicator bacteria enumeration in beach sand: A comparison study of extraction methods in medium to coarse sands

    Science.gov (United States)

    Boehm, A.B.; Griffith, J.; McGee, C.; Edge, T.A.; Solo-Gabriele, H. M.; Whitman, R.; Cao, Y.; Getrich, M.; Jay, J.A.; Ferguson, D.; Goodwin, K.D.; Lee, C.M.; Madison, M.; Weisberg, S.B.

    2009-01-01

    Aims: The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique. Methods and Results: Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. Conclusions: The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. Significance and Impact of the Study: Method standardization will improve the understanding of how sands affect surface water quality. ?? 2009 The Society for Applied Microbiology.

  9. Effect of mineral additives (natural pozzolana and sand of dunes) by substitution of cement on the performance and durability of mortars

    Science.gov (United States)

    Saidi, M.; Safi, B.

    2016-04-01

    The objective of our work consists of the study of the substitution effects of clinker by mineral additions such as: natural pozzolana (PZ) and the sand of dunes (SD) finely crushed on the mechanical properties and the durability of the mortars worked out according to various combinations containing these additions. The results from this research confirm that the substitution of 20% to 30% of cement APC (Artificial Portland Cement) by additions in binary cement (APC + PZ) or ternary (APC + PZ + SD) contributes positively to the mechanical strength of mortars and resistance to the chemical attacks in various corrosive conditions such as: hydrochloric acid, sulfuric acid and nitric acid. The mechanical strength of the different variants is comparable to those of the APC. The test results of the weight loss and phenolphthalein shows that the chemical resistance of variants (PZ20) and (PZ20 with SD5) are larger compared to the reference mortar APC and other variants. This study shows that adding value by substituting a part of clinker. This substitution can save 20% to 30% of clinker used for the manufacture of cement; this will have a beneficial effect for cement and economically (less energy spent for the clinker burning). This study contributes to the protection of the environment as to produce one ton of clinker generates about one ton of CO2 is harmful to the atmosphere. Based on our results we will reduce from 20% to 30% CO2 gas responsible for the greenhouse effect.

  10. 土工布加筋垫层对路基变形和稳定的影响%Effect of the geotextile-reinforced sand cushion on the deformation and stability of the foundation under a embankment

    Institute of Scientific and Technical Information of China (English)

    翁升; 马时冬

    2001-01-01

    某高速公路高填方路堤下的深厚软基,采用以塑料板排水为主,配合机织土工布加筋砂垫层进行了软基处理.在对有加筋砂垫层和无加筋砂垫层的软基变形性状进行比较的基础上,评价了加筋砂垫层的作用及效果.还通过计算,分析了机织土工布的预应变对路基稳定性的影响,从而说明施工加筋砂垫层时,对加筋材料施加预应变的重要性.% The soft foundation under a freeway compacted by high fill was treated mainly by drainage with plastic plates cooperated by woven geotextile-reinforced sand cushion. Based on the comparison of the deformation behavior of soft foundation of both reinforced sand cushion and ordinary sand cushion,the role and effect of the reinforced sand cushion were evaluated. At last,the effect of the prestrained geotextiles on the stability of the embankment was analyzed through calculation,thus the importance was shown of the prestrain in construction.

  11. Geologic and paleoecologic studies of the Nebraska Sand Hills

    Science.gov (United States)

    Ahlbrandt, Thomas S.; Fryberger, S.G.; Hanley, John H.; Bradbury, J. Platt

    1980-01-01

    . Further, our measurements indicate that dunes in the western part of the Sand Hills did not develop in response to present-day effective wind regimes. The presence of 'transverse' and en echelon barchan dunes in the Sand Hills corresponds to a developmental sequence of barchan to linear dunes proposed by Tsoar (1978). Dune and interdune deposits of the Sand Hills are subfeldsarenites to feldsarenites. Sand grains are commonly coated with montmorillonitic clay, which may be the local source of the clay concentrated in the dissipation structures. Textures of sand samples taken from adjacent layers within a dune were as dissimilar as textures of samples taken from widely separated dunes. This common occurrence indicates that textural data must be used carefully and in combination with other data to recognize ancient rocks of eolian origin. Organic material derived from a variety of flora and fauna that inhabit the interdunes (chapters B and C) generated both oil and gas upon heating. Thus, interdune sediments may be an indigenous hydrocarbon source if buried in eolianites. The twofold stratigraphy of loess and correlative dune deposits in the Sand Hills proposed by Reed and Dreeszen (1965) could not be confirmed by the present study. Rather, available data indicate that the dunes represent a single formation as suggested by Lugn (1935). PART B: Three assemblages of nonmarine Mollusca from paleointerdune deposits in the Nebraska Sand Hills inhabited shallow, quiet, vegetated, subpermanent or temporary, freshwater interdune ponds and adjacent terrestrial habitats. Analysis of factors affecting the taxonomic composition, diversity, and abundance of species in living assemblages of mollusks support this interpretation. The mollusks have long biostratigraphic ranges and broad biogeographic distributions. They fail to establish precise age relations of the faunas othe

  12. Slow-sand water filter: design, implementation, accessibility and sustainability in developing countries.

    Science.gov (United States)

    Clark, Peter A; Pinedo, Catalina Arango; Fadus, Matthew; Capuzzi, Stephen

    2012-07-01

    The need for clean water has risen exponentially over the globe. Millions of people are affected daily by a lack of clean water, especially women and children, as much of their day is dedicated to collecting water. The global water crisis not only has severe medical implications, but social, political, and economic consequences as well. The Institute of Catholic Bioethics at Saint Joseph's University has recognized this, and has designed a slow-sand water filter that is accessible, cost-effective, and sustainable. Through the implementation of the Institute's slow-sand water filter and the utilization of microfinancing services, developing countries will not only have access to clean, drinkable water, but will also have the opportunity to break out of a devastating cycle of poverty.

  13. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  14. Sand dollar sites orogenesis

    Science.gov (United States)

    Amos, Dee

    2013-04-01

    The determinology of the humble sand dollars habitat changing from inception to the drastic evolution of the zone to that of present day. Into the cauldron along the southern Californian 'ring of fire' lithosphere are evidence of geosynclinals areas, metasedimentary rock formations and hydrothermal activity. The explanation begins with 'Theia' and the Moon's formation, battles with cometary impacts, glacial ages, epochs with evolutionary bottlenecks and plate tectonics. Fully illustrated the lecture includes localised diagrams and figures with actual subject photographic examples of plutonic, granitic, jade and peridodite. Finally, the origins of the materials used in the lecture are revealed for prosecution by future students and the enjoyment of interested parties in general.

  15. Sand Storms Trigger Alarm

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ After an unusually humid winter with at least 10 snowfalls in Beijing, a severe andstorm blown by strong winds bringing with it thousands of tons of desert sand took many residents of the city by surprise.On the morning of March 20, Beijingers woke up to see clouds of yellow dust in the air and a sky that was an ominous orange in color.The loose soil and dust that had traveled htmdreds of miles from deserts in Mongolia and China's northwest blanketed Beijing's streets, covering parked vehicles, bikes, roofs and even plant life,as well as making its way into people's homes.

  16. Fortune Cookie Sand Dunes

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-432, 25 July 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a field of small barchan sand dunes in the north polar region near 71.7oN, 51.3oW. Some of them are shaped like fortune cookies. The message these dunes provide: winds blow through this region from the lower right toward the upper left. The steep slip face slopes of these dunes, which point toward the upper left, indicate the wind direction. The scene is illuminated by sunlight from the upper right. The image is 3 km (1.9 mi) wide.

  17. A family of sand automata

    CERN Document Server

    Faulkner, Nicholas

    2012-01-01

    We study some dynamical properties of a family of two-dimensional cellular automata: those that arise from an underlying one dimensional sand automaton whose local rule is obtained using a latin square. We identify a simple sand automaton G whose local rule is algebraic, and classify this automaton as having equicontinuity points, but not being equicontinuous. We also show it is not surjective. We generalise some of these results to a wider class of sand automata.

  18. Dilatometric Characterization of Foundry Sands

    Directory of Open Access Journals (Sweden)

    M. Břuska

    2012-04-01

    Full Text Available The goal of this contribution is summary of physical – chemistry properties of usually used foundry silica and no – silica sands in Czech foundries. With the help of dilatometry analysis theoretical assumptions of influence of grain shape and size on dilatation value of sands were confirmed. Determined was the possibility of dilatometry analysis employment for preparing special (hybrid sands with lower and/or more linear character of dilatation.

  19. Thermal aspects of temperature transformations in silica sand

    Directory of Open Access Journals (Sweden)

    J.St. Kowalski

    2010-07-01

    Full Text Available Problems related with the choice of moulding sand composition considering its behaviour in contact with molten metal were discussed.The investigations of high-temperature phenomena enable moulding sand composition to be evaluated in terms of its applicability underthe specific conditions of a foundry shop. It is also possible to eliminate the casting defects related to moulding sand and its properties. The investigations were carried out on selected moulding sands from the family of the traditional carbon-free moulding mixtures. The effect of moulding sand composition and moisture content on the linear dilatation and stress formation caused by an allotropic quartz transformation was determined. The investigated phenomena were analysed on 3D diagrams plotted from the test data. A strong effect of the beta quartz - alpha quartz transformation at a temperature of about 6000C was stated.

  20. Triaxial tests in Fontainebleau sand

    DEFF Research Database (Denmark)

    Latini, Chiara; Zania, Varvara

    2016-01-01

    The purpose of this internal report is to examine the influence of relative density on the strength and deformation characteristics of Fontainebleau sand. Compression triaxial tests were performed on saturated sand samples with different densities and initial confining pressure. Note that the tes......The purpose of this internal report is to examine the influence of relative density on the strength and deformation characteristics of Fontainebleau sand. Compression triaxial tests were performed on saturated sand samples with different densities and initial confining pressure. Note...... that the testing procedure and the data processing were carried out according to the specifications of ETCS-F1.97....

  1. The effect of oil sands process-affected water and model naphthenic acids on photosynthesis and growth in Emiliania huxleyi and Chlorella vulgaris.

    Science.gov (United States)

    Beddow, Jessica; Johnson, Richard J; Lawson, Tracy; Breckels, Mark N; Webster, Richard J; Smith, Ben E; Rowland, Steven J; Whitby, Corinne

    2016-02-01

    Naphthenic acids (NAs) are among the most toxic organic pollutants present in oil sands process waters (OSPW) and enter marine and freshwater environments through natural and anthropogenic sources. We investigated the effects of the acid extractable organic (AEO) fraction of OSPW and individual surrogate NAs, on maximum photosynthetic efficiency of photosystem II (PSII) (FV/FM) and cell growth in Emiliania huxleyi and Chlorella vulgaris as representative marine and freshwater phytoplankton. Whilst FV/FM in E. huxleyi and C. vulgaris was not inhibited by AEO, exposure to two surrogate NAs: (4'-n-butylphenyl)-4-butanoic acid (n-BPBA) and (4'-tert-butylphenyl)-4-butanoic acid (tert-BPBA), caused complete inhibition of FV/FM in E. huxleyi (≥10 mg L(-1)n-BPBA; ≥50 mg L(-1)tert-BPBA) but not in C. vulgaris. Growth rates and cell abundances in E. huxleyi were also reduced when exposed to ≥10 mg L(-1)n- and tert-BPBA; however, higher concentrations of n- and tert-BPBA (100 mg L(-1)) were required to reduce cell growth in C. vulgaris. AEO at ≥10 mg L(-1) stimulated E. huxleyi growth rate (p ≤ 0.002), yet had no apparent effect on C. vulgaris. In conclusion, E. huxleyi was generally more sensitive to NAs than C. vulgaris. This report provides a better understanding of the physiological responses of phytoplankton to NAs which will enable improved monitoring of NA pollution in aquatic ecosystems in the future.

  2. Simultaneous PIV and PTV measurements of wind and sand particle velocities

    Science.gov (United States)

    Zhang, Wei; Wang, Yuan; Lee, Sang Joon

    2008-08-01

    Wind-blown sand is a typical example of two-phase particle-laden flows. Owing to lack of simultaneous measured data of the wind and wind-blown sand, interactions between them have not yet been fully understood. In this study, natural sand of 100-125 μm taken from Taklimakan Desert was tested at the freestream wind speed of 8.3 m/s in an atmospheric boundary layer wind tunnel. The captured flow images containing both saltating sand and small wind tracer particles, were separated by using a digital phase mask technique. The 2-D PIV (particle imaging velocimetry) and PTV (particle tracking velocimetry) techniques were employed to extract simultaneously the wind velocity field and the velocity field of dispersed sand particles, respectively. Comparison of the mean streamwise wind velocity profile and the turbulence statistics with and without sand transportation reveal a significant influence of sand movement on the wind field, especially in the dense saltating sand layer ( y/ δ < 0.1). The ensemble-averaged streamwise velocity profile of sand particles was also evaluated to investigate the velocity lag between the sand and the wind. This study would be helpful in improving the understanding of interactions between the wind and the wind-blown sand.

  3. EFFECTS OF SAND MULCHING ON SOIL INFILTRATION, EVAPORATION,AND SALT DISTRIBUTION%覆砂对土壤入渗、蒸发和盐分迁移的影响

    Institute of Scientific and Technical Information of China (English)

    宋日权; 褚贵新; 张瑞喜; 白玲; 杨劲松

    2012-01-01

    探讨覆砂厚度对土壤水分入渗、蒸发、盐分迁移的影响,对新疆干旱区农田抑盐、保水及合理的覆砂制度制定具有重要意义.本文采用定水头法入渗和模拟稳定蒸发条件,研究覆砂厚度对土壤水分入渗、蒸发过程以及盐分迁移的影响.以覆砂厚度为影响因子,在土壤表层设置4个厚度,分别是0(对照)、1.7、3.6、5.7 cm.研究结果表明:(1)覆砂抑制了土壤水分净入渗能力,这一抑制作用随着覆砂厚度增加而减弱;(2)覆砂可以显著抑制土壤蒸发,随着覆砂厚度的增加抑制力增大.在20天蒸发过程中,覆砂处理蒸发呈稳定态势,且累积蒸发量符合线性方程,而对照符合Rose经验公式;(3)覆砂可以改变土壤盐分在剖面中的运移,尤其减弱了盐分的表聚.总之,覆砂显著地抑制了土壤蒸发和盐分表聚,即在覆砂厚1.7 cm上就可达显著效果,但对土壤的净入渗能力具有抑制作用.%Soil secondary salinity and fresh water shortage are two major problems limiting crop growth and yield improvement. Therefore, analysis of effects of sand mulching on soil water infiltration, evaporation, and salt transportation is of some great significance to optimizing the method of sand mulching in arid regions. A laboratory simulation experiment was conducted to study processes of soil water infiltration, soil water evaporation, and salt transportation under sand mulchings different in thickness, in the condition of constant water head infiltration and simulating steady evaporation.The sand used in this study varied from 0. 2 mm to 2 mm in particle size. The experiment was designed to have four treatments in sand mulching, I e. , 0 (control) , 1.7, 3.6 and 5.7 cm, in thickness of the sand layer on the surface of soil. Results show that (1) Sand mulching has an obvious inhibitory effect on soil water net infiltration, and the thicker the sand mulching the less the soil water infiltration, namely, the

  4. Effect of pH and Calcium on the Adsorptive Removal of Cadmium and Copper by Iron Oxide–Coated Sand and Granular Ferric Hydroxide

    KAUST Repository

    Uwamariya, V.

    2015-08-17

    Iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were used to study the effect of Ca2+ and pH on the adsorptive removal of Cu2+ and Cd2+ from groundwater using batch adsorption experiments and kinetic modeling. It was observed that Cu2+ and Cd2+ were not stable in synthetic waters. The extent of precipitation increased with increasing pH. Removal of Cu2+ and Cd2+ was achieved through both precipitation and adsorption, with IOCS showing higher adsorption efficiency. Increase of pH (from 6 to 8) resulted in a higher overall removal efficiency of both Cu2+ and Cd2+, with precipitation as predominant removal mechanisms at higher pH values, especially for Cu2+. An increase in Ca2+ concentration increased the precipitation of Cu2+ [as Cu2(OH)2CO3 and Cu3(OH)2(CO3)2] and Cd2+ [as Cd(OH)2 and CdCO3]. In addition, Ca2+ competes with Cu2+ and Cd2+ for surface adsorption sites on IOCS and GFH, and reduces their adsorption capacity. The kinetic modeling revealed that the adsorption of Cd2+ onto IOCS is a complex process, with limited contribution of chemisorption that increases in the presence of Ca2+. © 2015 American Society of Civil Engineers.

  5. Effect of over-consolidation and shear rate on the residual strength of soils of silty sand in the Three Gorges Reservoir.

    Science.gov (United States)

    Li, Deying; Yin, Kunlong; Glade, Thomas; Leo, Chin

    2017-07-14

    Estimation of the residual strength of the soil on the landslide sliding surface is essential for analyzing reactivated landslides. This study investigated the influence of over-consolidation ratio (OCR) and shear rate on the residual strength of SM-type (silty sand) landslide soils in the Three Gorge Reservoir using ring shear tests under drained conditions. A series of ring shear tests were conducted to measure the drained residual strength under over-consolidation ratios of 1-12 and shear rates of 0.06-30.00 mm/min. Test results showed that residual strengths of SM-type landslide soils were not affected significantly by the over-consolidation process. The effect of shear rate on residual strength did not exhibit a regular pattern at shear rates of 0.06-10.00 mm/min, and behaved negatively at a high shear rate of 30 mm/min. The reduction in residual strength at higher shear rates may be attributable to increases in the water content of the shear zone and the amount of finer particles, due to particle breakage and/or larger grains being pushed from the shear zone.

  6. Effect of Carbon and Nitrogen Sources on Polygalacturonase Production by Trichoderma viride (BITRS-1001 Isolated from Tar Sand in Ondo State, Nigeria

    Directory of Open Access Journals (Sweden)

    Ogunmolu, F. E.

    2011-01-01

    Full Text Available The effects of the various carbon and nitrogen substrates on the growth and polygalacturonase activity of Trichoderma viride (BITRS-1001 isolated from the tar sand deposit in Gbelejuloda-Irele Ondo State, Nigeria were investigated in submerged cultivation at 30 °C ± 2 °C. The commercial carbon and nitrogen substrates included sucrose, fructose, starch, maltose, lactose and peptone, sodium nitrate, urea and casein respectively. All the carbon substrates used supported the growth of T. viride (0.566 to 0.156 g/50 mL of culture medium with starch supporting the highest biomass yield and sucrose the least biomass yield. Maximum polygalacturonase activity of 3033 U/mL was recorded in maltose medium. Maximum biomass yield on the nitrogen sources was observed in the organic nitrogen namely peptone and casein with values not significantly different from each other at p ≤ 0.05. In the determination of the crude enzyme activity on the nitrogen sources, maximum polygalacturonase activity of 12,400 U/mL was recorded in peptone medium. Hence, a careful manipulation of these nutrient substrates could help to optimise the production of this enzyme on a large scale.

  7. Patterns of sand fractions influence on microalgae of the marine coast

    Directory of Open Access Journals (Sweden)

    Anastasiya Snigirova

    2015-04-01

    Full Text Available To study effect of grain size on microalgae a new method is proposed: sand of different fractions is glued to the surface of microscope slides. Microalgae abundance was higher on fine sand grains (<0,25 mm. To forecast microalgae abundance the pattern is proposed depending on size of sand grains. 

  8. Properties of sodium silicate bonded sand hardened by microwave heating

    Institute of Scientific and Technical Information of China (English)

    Wang Jina; Fan Zitian; Zan Xiaolei; Pan Di

    2009-01-01

    The sodium silicate bonded sand hardened by microwave heating has many advantages,such as low sodium silicate adding quantity,fast hardening speed,high room temperature strength,good collapsibility and certain surface stability. However,it has big moisture absorbability in the air,which would lead to the compression strength and the surface stability of the sand molds being sharply reduced. In this study,the moisture absorbability of the sodium silicate bonded sand hardened by microwave heating in different humidity conditions and the effect factors were investigated. Meanwhile,the reasons for the big moisture absorbability of the sand were analyzed.Some measures to overcome the problems of high moisture absorbability,bad surface stability and sharply reducing strength in the air were discussed. The results of this study establish the foundation of green and clean foundry technology based on the microwave heating hardening sodium silicate sand process.

  9. A sand wave simulation model

    NARCIS (Netherlands)

    Nemeth, A.A.; Hulscher, S.J.M.H.; Damme, van R.M.J.

    2003-01-01

    Sand waves form a prominent regular pattern in the offshore seabeds of sandy shallow seas. A two dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of these sand waves has been developed. The model contains the 2DV shallow water equations, with a free water su

  10. Regeneration of dredged sand waves

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; Knaapen, Michiel; Scholl, Olaf; Scholl, O.; Trenteseaux., A.; Garlan, T.

    2000-01-01

    Sand waves form a wavy pattern in the offshore sandy seabed. Since their crests reduce the navigability, it is important to know their evolution. A simple model is presented to estimate the recovery of sand wave amplitudes. This model is partially based on the similarity with sea ripples and

  11. Namibia : triaxial test on sand

    DEFF Research Database (Denmark)

    Steenfelt, Jørgen S.; Jacobsen, Kim P.

    In connection with a harbour project the friction angle of a fine sand is required. On Friday 13 March 1998 the Danish Geotechnical Institute (DGI) delivered app. 2.5 kg sand for testing at the Geotechnical Engineering Laboratory, Aalborg University. The present Data Report summarises the results...

  12. Kirsten Sand. Arkitekt for sin tid

    Directory of Open Access Journals (Sweden)

    Elisabeth Seip

    2015-12-01

    Full Text Available Towards the end of World War II the retreating Germans burnt down nearly all buildings and other constructions in the counties of Finnmark and the northern parts of Troms in North Norway. The population evacuated but many returned as soon as possible, only to find themselves homeless. At this very demanding point Kirsten Sand decided to travel north, and do whatever she could as an architect to help. The pre-war housing situation was generally difficult. Low building standards and lack of money forced families in the cities to live under bad conditions. Kirsten Sand studied these conditions and took part in the efforts to better the situation. This knowledge provided a good starting point for the work she undertook after the war, in particular her profound understanding of the situation of women, their working conditions and positions in the household and society. Houses designed by Sand and her helpmates are simple but adequate, taking into account these women’s point of view. Ingebjørg Hage has thrown light on the work of Kirsten Sand in Finnmark and Troms in several ways. This article aims at describing Sand’s background as an architect before she left Oslo to travel north. It describes how housing and housing policy since long had been central to architects, especially so within the group she belonged to. In pre-war Oslo she had been engaged in planning and designing hospitals. During a period as inspector for the health authorities she learned a lot about the living conditions of people in general. After establishing her own architect’s office she mostly designed family houses, and during the war she engaged in research that further deepened her knowledge in the field. Thus she was particularly well equipped for the demanding tasks she undertook in the summer of 1945.

  13. Effect of lacking intestinal bile acid on liver regeneration in rats%肠道缺乏胆汁酸对大鼠肝再生的影响

    Institute of Scientific and Technical Information of China (English)

    董秀山; 赵浩亮

    2010-01-01

    Objective To investigate the effect of the lack of intestinal bile on liver regeneration after hepatectomy.Methods The model of interference with intestinal bile acid metabolism in rats was established by feeding rats with 0.2% cholic acid(cholic acid loading group), 2% cholestyramine resin(lack of bile group)and feeding the standard diet as the control group.Liver regeneration was compared among the 3 groups at 0, 1, 2, 3, and 7 d after 70% partial hepatectomy(PH)in rats and mRNA expression of the rate-limiting enzyme of bile acid biosynthesis(CYP7a1)and farnesoid X receptor (FXR)were detected.Results The rate of liver regeneration was significantly lower on days 3 and 7after PH in the lack of bile group than in the other groups(P<0.05).On day 1, the labeling indices of PCNA and Ki-67 in the lack of bile group(22.21% ±2.31%、 17.25 % ± 6.50 %)were lower than those in the cholic acid loading group(44.4%±4.92%、 30.83% ± 3.91%)and control group (38.74% ±6.42% 、27.04% ±7.22%)and the peaking of labeling indices was delayed.After PH, the mRNA expression of FXR was significantly lower in the lack of bile group than in other groups.However, CYP7al mRNA had a trend towards increase after PH and was higher than that in other groups.Conclusion Lack of intestinal bile results in delayed liver regeneration of normal rat liver accompanied by decreased expression of FXR mRNA after hepatectomy.%目的 探索肠道缺乏胆汁酸对肝再生的影响.方法 通过喂养大鼠0.2%胆酸(胆酸负荷组)、2%考来烯胺(胆酸缺乏组)建立干扰肠道胆汁酸代谢的动物模型,以喂养标准饲料作为对照组,所有大鼠均行70%肝部分切除术(PH).比较PH后0、1、2、3、7 d三组大鼠的肝脏再生情况,并检测法尼酯衍生物X受体FXR及其靶基因胆汁酸合成限速酶CYP7a1的mRNA表达.结果 胆酸缺乏组的肝再生率在PH后3、7 d显著低于胆酸负荷组和对照组(P<0.05),1 d时PCNA和Ki-67标记指数(22.21%±2.31%、17

  14. Louisiana residents' self-reported lack of information following the Deepwater Horizon oil spill: Effects on seafood consumption and risk perception.

    Science.gov (United States)

    Simon-Friedt, Bridget R; Howard, Jessi L; Wilson, Mark J; Gauthe, David; Bogen, Donald; Nguyen, Daniel; Frahm, Ericka; Wickliffe, Jeffrey K

    2016-09-15

    In 2010, the Deepwater Horizon (DWH) oil spill adversely impacted many communities along the Gulf of Mexico. Effects on Gulf waters, marshes, aquatic life, and fisheries were evident in the following days, months, and years. Through studying affected communities' perceptions regarding the DWH accident, we aim to identify behavioral changes, understand public information sources, and inform dissemination strategies that improve communications from regulatory agencies. Over a three-year period (2012-2015), residents (n = 192) from 7 coastal parishes in southeast Louisiana were surveyed about their perceptions and behaviors before, during, and after the DWH accident. Self-reported consumption of local seafood decreased significantly (50%) during the DWH oil spill but returned to pre-event reported levels by 2015. However, negative seafood quality perceptions remain and have not returned to what were generally positive pre-event levels. Over 30% of study participants trust relatives, friends, and neighbors more than government officials or scientists as information sources regarding locally harvested seafood. Importantly, nearly 50% of participants report that they lack the information needed to make informed decisions regarding the safety of consuming local seafood. We conclude that a lack of information and trust in government agencies exacerbated negative perceptions of oil spill-related dangers. In some cases, overestimation of perceived dangers likely led to behavioral modifications that persist today. Efforts should be made to improve relationships between public health agencies and communities in order to properly inform all citizens of risks following environmental disasters.

  15. Louisiana residents’ self-reported lack of information following the Deepwater Horizon oil spill: Effects on seafood consumption and risk perception

    Science.gov (United States)

    Simon-Friedt, Bridget R.; Howard, Jessi L.; Wilson, Mark J.; Gauthe, David; Bogen, Donald; Nguyen, Daniel; Frahm, Ericka; Wickliffe, Jeffrey K.

    2016-01-01

    In 2010, the Deepwater Horizon (DWH) oil spill adversely impacted many communities along the Gulf of Mexico. Effects on Gulf waters, marshes, aquatic life, and fisheries were evident in the following days, months, and years. Through studying affected communities’ perceptions regarding the DWH accident, we aim to identify behavioral changes, understand public information sources, and inform dissemination strategies that improve communications from regulatory agencies. Over a three-year period (2012 −2015), residents (n = 192) from 7 coastal parishes in southeast Louisiana were surveyed about their perceptions and behaviors before, during, and after the DWH accident. Self-reported consumption of local seafood decreased significantly (50%) during the DWH oil spill but returned to pre-event reported levels by 2015. However, negative seafood quality perceptions remain and have not returned to what were generally positive pre-event levels. Over 30% of study participants trust relatives, friends, and neighbors more than government officials or scientists as information sources regarding locally harvested seafood. Importantly, nearly 50% of participants report that they lack the information needed to make informed decisions regarding the safety of consuming local seafood. We conclude that a lack of information and trust in government agencies exacerbated negative perceptions of oil spill-related dangers. In some cases, overestimation of perceived dangers likely led to behavioral modifications that persist today. Efforts should be made to improve relationships between public health agencies and communities in order to properly inform all citizens of risks following environmental disasters. PMID:27289418

  16. Sand swimming lizard: sandfish

    CERN Document Server

    Maladen, Ryan D; Kamor, Adam; Goldman, Daniel I

    2009-01-01

    We use high-speed x-ray imaging to reveal how a small (~10cm) desert dwelling lizard, the sandfish (Scincus scincus), swims within a granular medium [1]. On the surface, the lizard uses a standard diagonal gait, but once below the surface, the organism no longer uses limbs for propulsion. Instead it propagates a large amplitude single period sinusoidal traveling wave down its body and tail to propel itself at speeds up to ~1.5 body-length/sec. Motivated by these experiments we study a numerical model of the sandfish as it swims within a validated soft sphere Molecular Dynamics granular media simulation. We use this model as a tool to understand dynamics like flow fields and forces generated as the animal swims within the granular media. [1] Maladen, R.D. and Ding, Y. and Li, C. and Goldman, D.I., Undulatory Swimming in Sand: Subsurface Locomotion of the Sandfish Lizard, Science, 325, 314, 2009

  17. Effects of timber harvest on phlebotomine sand flies (Diptera: Psychodidae in a production forest: abundance of species on tree trunks and prevalence of trypanosomatids

    Directory of Open Access Journals (Sweden)

    Felipe Arley Costa Pessoa

    2007-08-01

    Full Text Available The Amazon forest is being exploited for timber production. The harvest removes trees, used by sand flies as resting sites, and decreases the canopy, used as refuges by some hosts. The present study evaluated the impact of the timber harvest, the abundance of sand flies, and their trypanosomatid infection rates before and after selective logging. The study was accomplished in terra-firme production forest in an area of timber harvest, state of Amazonas, Brazil. Sand fly catches were carried out in three areas: one before and after the timber harvest, and two control areas, a nature preservation area and a previously exploited area. The flies were caught by aspiration on tree trunks. Samples of sand flies were dissected for parasitological examination. In the site that suffered a harvest, a larger number of individuals was caught before the selective extraction of timber, showing significant difference in relation to the number of individuals and their flagellate infection rates after the logging. The other two areas did not show differences among their sand fly populations. This fact is suggestive of a fauna sensitive to the environmental alterations associated with selective logging.

  18. 2010 oil sands performance report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    With the depletion of traditional energy resources and the rising demand for energy, oil sands have become an important energy resource for meeting energy needs. Oil sands are a mixture of water, sand, clay and bitumen which is recovered either through open pit mining or in situ drilling techniques. The bitumen is then converted into syncrude or sold to refineries for the production of gasoline, diesel or other products. Shell has oil sands operations in Alberta and the aim of this report is to present its 2010 performance in terms of CO2, water, tailings, land, and reclamation and engagement. This document covers several of Shell's operations in the Muskeg River and Jackpine mines, Scotford upgrader, Peace River, Orion, Seal, Cliffdale and Chipmunk. It provides useful information on Shell's oil sands performance to governments, environmental groups, First Nations, local communities and the public.

  19. Addition of fly ash to reduce lime and energy requirements in the production of sand-lime bricks. Moeglichkeiten zur Reduzierung des Kalk- und Energiebedarfes bei der Kalksandsteinherstellung durch den Zusatz von Flugasche

    Energy Technology Data Exchange (ETDEWEB)

    Wittneben, U.

    1988-01-01

    The author studies fly ashes and their possible use as additives in the sand-lime brick production in terms of cost-effectiveness achievable in SL brick technology and the effects of fly ash additives on major brick properties. Studies involved 14 black-coal fly ashes from different power plants and 2 brown-coal fly ashes. The effects achievable by fly ash additives strongly depend from the properties of fly ash and from the grain structure of the sand additive. The brown-coal fly ashes included in this study were found to be unsuitable for S-L bricks due to their lack of volume stability.

  20. Shifting Sands in the United Arab Emirates: Effecting Conceptual Change for Creativity in Early Childhood Teacher Education

    Science.gov (United States)

    Baker, Fiona S.

    2013-01-01

    This study examines the effectiveness of a four-stage conceptual change approach to creativity development in teacher education in the Emirate of Dubai, the United Arab Emirates. The participants were 32 student teachers studying at undergraduate level at an all-female university. The study examined participant preconceptions of creativity and how…

  1. Comparison of two Satellite Imaging Platforms for Evaluating Sand Dune Migration in the Ubari Sand Sea (Libyan Fazzan)

    Science.gov (United States)

    Els, A.; Merlo, S.; Knight, J.

    2015-04-01

    Sand dunes can change location, form or dimensions depending on wind direction and strength. Sand dune movements can be effectively monitored through the comparison of multi-temporal satellite images. However, not all remote sensing platforms are suitable to study sand dunes. This study compares coarse (Landsat) and fine (Worldview) resolution platforms, specifically focussing on sand dunes within the Ubari Sand Sea (Libya). Sand dune features (crest line, dune ridge basal outlines) were extracted from Landsat and Worldview 2 imagery in order to construct geomorphic maps. These geomorphic maps were then compared using image overlay and differencing, and the Root Mean Squared Error (RMSE) was used to determine if the mapped dune patterns were significantly different. It was found that Landsat is a sufficient data source when studying dune patterns within a regional sand sea, but smaller dunes identified from Worldview data were not capable of being extracted in the data sourced from Landsat. This means that for studies concerned with the dune patterns and movements within sand seas, Landsat is sufficient. But in studies where the specific dynamics of specific dunes are required, a finer resolution is required; platforms such as Worldview are needed in order to gain more detailed insight and to link the past and present day climate and environmental change.

  2. Transport and Retention of CdSe/ZnS Quantum Dots in Saturated Sand: Effects of Organic Ligands, pH and Ionic Strength

    Science.gov (United States)

    Li, Chunyan; Snee, Preston; Darnault, Christophe

    2016-04-01

    The presence of nanomaterials in soil, water, and air systems following their life cycle or accidents and their effects on the environment and public health are inevitable. Ability to forecast the public health and ecological impacts of these nanomaterials encountered in the environment is limited. Therefore, it is critical to be able to predict the fate and transport on nanomaterials in the environment, in particular the subsurface, in order to conduct risk assessments. To assess the transport and retention of nanomaterials in the subsurface environment, we selected quantum dots (QDs). QDs are metal and semiconductor based nanomaterials that are essential to nanoscience and nanotechnology. Understanding the parameters that effect the transport and retention of QDs in the soil water environment is critical. Natural organic ligands are commonly found in soils and impact the soil physico-chemical processes through multifaceted reactions with metal ions present in soil solution and ligand exchange reactions on soil surfaces. Therefore, ligands may modify the surface properties of QDs and effect their stability, transport and retention in the subsurface environment. In this research, size, surface charge, and stability of CdSe/ZnS QDs in water solutions are monitored in batch experiments. The influence of organic ligands (acetate, oxalate, and citrate) on the stability of QDs at different pHs (1.5, 3.5, 5, 7 and 9) and ionic strengths (0.05 and 0.1 M) conditions were examined. The stability and aggregation phenomena of QDs were studied using UV-vis and DLS methods. Parameters from batch studies were selected to establish chemical conditions to be used in transport experiments to produce breakthrough curves and retention profiles in order to characterize the fate and transport of QDs in saturated sand. These transport experiments are essential to understand the mobility and retention processes in porous media where QD interactions with surfaces of heterogeneous

  3. Cumulative environmental management and the oil sands

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    In response to concerns regarding the cumulative environmental impacts of oil sands development within the Athabasca oil sands deposit, the government of Alberta established a Regional Sustainable Development Strategy (RSDS) to balance development with environmental protection. The environmental issues identified through the RSDS were addressed by the Cumulative Environmental Management Association (CEMA). CEMA's boundary is the Wood Buffalo region of northeastern Alberta. It identifies existing and future environmental effects in the region and proposes recommendations to regulatory bodies for reducing environmental impacts associated with oil sands development. This presentation outlined some of the 55 stakeholder representatives of CEMA, including Alberta government departments associated with resource development, oil sand developers within the region, and Aboriginal communities and First Nations. These stakeholders provide input on sector priorities and agree on environmental thresholds. Established working groups also address technical and scientific research issues identified in the RSDS such as sustainable ecosystems; surface waters; trace metals and air contaminants; nitrogen oxides and sulphur dioxides; and land reclamation. To date, CEMA has submitted more than 50 reports and has made 4 major environmental recommendations for trace metal management, ecosystem management tools, a framework for acid deposition management, and a landscape design checklist. tabs., figs.

  4. Effects of 17α-ethinyl estradiol on the mating system of the sand goby (Pomatoschistus minutus)

    OpenAIRE

    Saaristo, Minna

    2009-01-01

    In aquatic environments, endocrine disrupting chemicals (EDCs) that interfere with the endocrinology of males and females form a threat to the maintenance of populations. EDCs are a diverse group of natural and manmade chemicals that already at very low concentrations (at nanogram levels) can have severe effects on reproduction by individuals, e.g. complete sex reversal, feminisation of males, impaired reproduction even resulting in near extinction of populations. With regard to fish, despite...

  5. 矿物掺合料对珊瑚砂混凝土性能的影响%Effect of Mineral Admixtures on Coral Sand Concrete

    Institute of Scientific and Technical Information of China (English)

    陈友治; 马章强; 孙涛; 程书凯

    2016-01-01

    该文以珊瑚砂作为细骨料来配制C30珊瑚砂混凝土,研究了粉煤灰、矿粉、偏高岭土对珊瑚砂混凝土的力学性能、氯离子扩散系数影响规律,并通过 XRD、TG对其微观机理进行初步分析。研究结果表明,掺加粉煤灰会降低珊瑚砂混凝土的强度,矿粉对于珊瑚砂混凝土的强度影响较小,而掺加偏高岭土会明显提高珊瑚砂混凝土的抗压强度和降低氯离子扩散系数,减少Ca(OH)2的含量,使珊瑚砂混凝土的渗透性能得到优化。%The coral sand was used as fine aggregate to formulate C30 coral sand concrete.And the influence of fly ash,slag,metakaolin ws studied on the mechanical properties and chloride ion diffusion coefficient of coral sand con-crete,and then using XRD,TG their preliminary microscopic mechanism was analyzed.The results showed that,fly ash will reduce the strength of coral sand concrete,slag has little influence for the coral sand concrete,while metakaolin will significantly improve the compressive strength of coral sand concrete and reduce the chloride ion diffusion coefficient, reduce Ca(OH)2 content of concrete,and the permeability of concrete are optimized.

  6. Biodegradation in a Partially Saturated Sand Matrix: Compounding Effects of Water Content, Bacterial Spatial Distribution, and Motility

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Owsianiak, Mikolaj; Bazire, Alexis

    2010-01-01

    colonizing these zones or on pollutant mass transfer to neighboring zones containing degraders. In a model system, we quantified the role exerted by water on mineralization rate in the context of a heterogeneously distributed degradation potential. Alginate beads colonized by Pseudomonas putida KT2440 were......Bacterial pesticide degraders are generally heterogeneously distributed in soils, leaving soil volumes devoid of degradation potential. This is expected to have an impact on degradation rates because the degradation of pollutant molecules in such zones will be contingent either on degraders......, partially relieving the diffusion limitation. Dry conditions, however, sustained low mineralization rates through the combined effects of low pollutant diffusivity and limited degrader dispersal....

  7. Effects of solid water and foliar fertilizer on survival and growth of seedlings in sand prevention and control

    Institute of Scientific and Technical Information of China (English)

    WANG Yutao; LI Jiyue; LIU Ping

    2007-01-01

    To promote afforestation in sandy lands and increase the effects of prevention and control of desertification,the application of a new drought-resistant productsolid water and foliar fertilizer "Shifengle"-was studied.A comparison of three treatments (solid water,foliar fertilizer,and control) showed that both solid water and foliar fertilizer increased plant survival rate by 10% and 18.2%,respectively.Afforestation survival rates of Salix psammophila and Hedysarum mongolicum reached over 90%.In addition,height and crown growth as well as biomass of seedlings were improved by the treatments.

  8. Effect of State of Stress on Velocity of Low-Amplitude Shear Waves Propagating along Principal Stress Directions in Dry Sand.

    Science.gov (United States)

    1982-03-01

    overconsolidation ratio, k = function of soil plasticity (k = 0 for sands), e = void ratio, Pa = atmospheric pressure in units of Gax* max K1 27 n slope of log G max...on soil Plasticity Index, w 37 j = elastic Poisson’s ratio, r 2 F(e) = function of void ratio (F(e) = 0.3 + 0.7e2), n = slope of log G - log a0...OCR = overconsolidation ratio, k = factor related to soil plasticity (for sand, k = 0), Pa = atmospheric pressure in same units as Gm e = void ratio

  9. Effect of heat treatment on corrosion behavior of low pressure sand cast Mg-10Gd-3Y-0.5Zr alloys

    OpenAIRE

    2016-01-01

    The corrosion behaviors of low-pressure sand cast Mg-10Gd-3Y-0.5Zr (wt.%) alloys in as-cast, solution treated (T4) and aged (T6) conditions were studied by means of immersion test and electrochemical measurements in 5wt.% NaCl solution saturated with Mg(OH)2. It was observed that the corrosion rate in the T4 condition was lower than that of the as-cast and T6 conditions by both sand casting and permanent mold casting with the same order of as-cast>T6>T4; while the corrosion resistance of the ...

  10. Laboratory studies of dune sand for the use of construction industry in Sri Lanka

    Science.gov (United States)

    de Silva Jayawardena, Upali; Wijesuriya, Roshan; Abayaweera, Gayan; Viduranga, Tharaka

    2015-04-01

    With the increase of the annual sand demand for the construction industry the excessive excavation of river sand is becoming a serious environmental problem in Sri Lanka. Therefore, it is necessary to explore the possibility for an alternative to stop or at least to minimize river sand mining activities. Dune sand is one of the available alternative materials to be considered instead of river sand in the country. Large quantities of sand dunes occur mainly along the NW and SE coastal belt which belong to very low rainfall Dry Zone coasts. The height of dune deposits, vary from 1m to about 30 meters above sea level. The objective of this paper is to indicate some studies and facts on the dune sand deposits of Sri Lanka. Laboratory studies were carried out for visual observations and physical properties at the initial stage and then a number of tests were carried out according to ASTM standards to obtain the compressive strength of concrete cylinders and mortar cubes mixing dune sand and river sand in different percentages keeping a constant water cement ratio. Next the water cement ratio was changed for constant dune sand and river sand proportion. Microscopic analysis shows that the dune sand consist of 95 % of quartz and 5 % of garnet, feldspar, illmenite and other heavy minerals with clay, fine dust, fine shell fragments and organic matters. Grains are sub-rounded to angular and tabular shapes. The grain sizes vary from fine to medium size of sand with silt. The degree of sorting and particle size observed with dune sands are more suited with the requirement of fine aggregates in the construction industry. The test result indicates that dune sand could be effectively used in construction work without sieving and it is ideal for wall plastering due to its'-uniformity. It could also be effectively used in concrete and in mortars mixing with river sand. The best mixing ratio is 75% dune sand and 25% river sand as the fine aggregate of concrete. For mortar the mixing

  11. Microbes in Beach Sands: Integrating Environment, Ecology and Public Health.

    Science.gov (United States)

    Whitman, Richard; Harwood, Valerie J; Edge, Thomas A; Nevers, Meredith; Byappanahalli, Muruleedhara; Vijayavel, Kannappan; Brandão, João; Sadowsky, Michael J; Alm, Elizabeth Wheeler; Crowe, Allan; Ferguson, Donna; Ge, Zhongfu; Halliday, Elizabeth; Kinzelman, Julie; Kleinheinz, Greg; Przybyla-Kelly, Kasia; Staley, Christopher; Staley, Zachery; Solo-Gabriele, Helena M

    2014-09-01

    Beach sand is a habitat that supports many microbes, including viruses, bacteria, fungi and protozoa (micropsammon). The apparently inhospitable conditions of beach sand environments belie the thriving communities found there. Physical factors, such as water availability and protection from insolation; biological factors, such as competition, predation, and biofilm formation; and nutrient availability all contribute to the characteristics of the micropsammon. Sand microbial communities include autochthonous species/phylotypes indigenous to the environment. Allochthonous microbes, including fecal indicator bacteria (FIB) and waterborne pathogens, are deposited via waves, runoff, air, or animals. The fate of these microbes ranges from death, to transient persistence and/or replication, to establishment of thriving populations (naturalization) and integration in the autochthonous community. Transport of the micropsammon within the habitat occurs both horizontally across the beach, and vertically from the sand surface and ground water table, as well as at various scales including interstitial flow within sand pores, sediment transport for particle-associated microbes, and the large-scale processes of wave action and terrestrial runoff. The concept of beach sand as a microbial habitat and reservoir of FIB and pathogens has begun to influence our thinking about human health effects associated with sand exposure and recreational water use. A variety of pathogens have been reported from beach sands, and recent epidemiology studies have found some evidence of health risks associated with sand exposure. Persistent or replicating populations of FIB and enteric pathogens have consequences for watershed/beach management strategies and regulatory standards for safe beaches. This review summarizes our understanding of the community structure, ecology, fate, transport, and public health implications of microbes in beach sand. It concludes with recommendations for future work in

  12. Modelling Effects of Cover Material and Cover Depth on Hydrological Regime and Salt Redistribution in Reclaimed Oil Sand Landscapes in Northern Alberta

    Science.gov (United States)

    Welegedara, N.; Grant, R. F.; Quideau, S.; Lloret, E.

    2014-12-01

    Large-Scale surface mining is continuing in the Athabasca oil sands region in northern Alberta, Canada, causing significant ecosystem disturbances and changes in hydrology. Reclamation efforts in this region require understanding processes that control water, nutrient and salt fluxes through reclaimed landscapes which is critical to restoring their productivity. These processes were tested in a comprehensive mathematical model, ecosys, which was used to determine the effect of different cover thicknesses on water balance, water buffering capacity, salinity and the productivity in the South Bison Hills reclamation site of Syncrude Canada (SCL). This site was constructed in 1999 by capping peat mineral mix and secondary (glacial till) soil over saline sodic overburden. The site was constructed with three different soil cover thicknesses: 35 cm (thin), 50 cm (intermediate) and 100 cm (thick) along a 20% north facing slope. Model outputs were validated with field measured volumetric water content, runoff, snow data, electrical conductivity (EC) and plant productivity data recorded from 1999 to 2013. Model and field results show differences in horizontal and vertical water transport among the three reclaimed prototype covers. Lower water retention capacity in the 35 cm cover compared to the 50 cm and 100 cm covers caused greater soil moisture variation so that permanent wilting point was reached during dry years, decreasing plant growth due to water stress. In addition, the modeled and field-measured EC values indicated some upward salt movement from overburden to cover material over the time. This movement caused higher EC values (6 - 8 dS m-1) to be reached in the shallow rooting zone of the 35 cm and 50 cm covers than of the 100 cm cover several years after the covers were established. The determination of cost effective but ecologically sustainable cover depth is a challenge and will be a focus in future simulations.

  13. Effect in water purification by airlift sand filter in aquaculture system%气提式砂滤器在水产养殖系统中的水质净化效果

    Institute of Scientific and Technical Information of China (English)

    于冬冬; 倪琦; 庄保陆; 张宇雷; 单建军; 管崇武; 张成林; 吴凡

    2014-01-01

    Traditional pressure sand filter after long time working intercepts large amounts of solid particles and leads to difficult backwash. In order to solve these problems, this study developed an airlift sand filter that can backwash itself while operating by optimizing a traditional filter. The airlift sand filter itself had filtration, separation, flotation, and self-cleaning functions, and could replace the traditional sand filters such as filter cell without valve, mechanical air flotation and other physical filtration device in aquaculture workshop. In the airlift sand filter, quartz sand (in diameter of 1-2 mm) was used as the filter medium, and the aquaculture sewage was flowed upward slowly from the bottom, thus quartz sand could intercept the suspended solids. Meanwhile, the fixed flow gas flowed from the bottom pushed dirt and quartz sand upwards simultaneously. During this process, sand and water were sufficiently contacted with each other. The interaction force between the sand and seawater resulted in production of a large number of bubbles. The suspended solids were then wrapped with the bubbles while quartz sand was cleaned by the sand washing device on the top of the system. The cleaned sand fallen back to the filter system by the gravity, and the suspended solids and waste water flowed out of the outfall. The airlift sand filter has the advantages of simple equipment, convenient operation, backwash without stopping the equipment, smooth and continuous system running, low energy consumption and easy to maintain and repair. The efficiency of the airlift sand filter used for marine recirculating aquaculture systems of the suspended solids (SS) and chemical oxygen demand (COD) was tested. Results showed that removal efficiency of SS and COD by this filter was 41.31%and 34.04%, respectively. Before the filtration, the number of large particles suspended solids (60 μm or higher) was 11.1%, its mass fraction was 71.77% and its mass concentration was 93.53 mg

  14. Advanced Techniques for Simulating the Behavior of Sand

    Science.gov (United States)

    Clothier, M.; Bailey, M.

    2009-12-01

    Computer graphics and visualization techniques continue to provide untapped research opportunities, particularly when working with earth science disciplines. Through collaboration with the Oregon Space Grant and IGERT Ecosystem Informatics programs we are developing new techniques for simulating sand. In addition, through collaboration with the Oregon Space Grant, we’ve been communicating with the Jet Propulsion Laboratory (JPL) to exchange ideas and gain feedback on our work. More specifically, JPL’s DARTS Laboratory specializes in planetary vehicle simulation, such as the Mars rovers. This simulation utilizes a virtual "sand box" to test how planetary rovers respond to different terrains while traversing them. Unfortunately, this simulation is unable to fully mimic the harsh, sandy environments of those found on Mars. Ideally, these simulations should allow a rover to interact with the sand beneath it, particularly for different sand granularities and densities. In particular, there may be situations where a rover may become stuck in sand due to lack of friction between the sand and wheels. In fact, in May 2009, the Spirit rover became stuck in the Martian sand and has provided additional motivation for this research. In order to develop a new sand simulation model, high performance computing will play a very important role in this work. More specifically, graphics processing units (GPUs) are useful due to their ability to run general purpose algorithms and ability to perform massively parallel computations. In prior research, simulating vast quantities of sand has been difficult to compute in real-time due to the computational complexity of many colliding particles. With the use of GPUs however, each particle collision will be parallelized, allowing for a dramatic performance increase. In addition, spatial partitioning will also provide a speed boost as this will help limit the number of particle collision calculations. However, since the goal of this

  15. Reinforcing Effects Of Compounds Lacking Intrinsic Efficacy At α1 Subunit-Containing GABAA Receptor Subtypes in Midazolam- But Not Cocaine-Experienced Rhesus Monkeys

    Science.gov (United States)

    Shinday, Nina M; Sawyer, Eileen K; Fischer, Bradford D; Platt, Donna M; Licata, Stephanie C; Atack, John R; Dawson, Gerard R; Reynolds, David S; Rowlett, James K

    2013-01-01

    Benzodiazepines are prescribed widely but their utility is limited by unwanted side effects, including abuse potential. The mechanisms underlying the abuse-related effects of benzodiazepines are not well understood, although α1 subunit-containing GABAA receptors have been proposed to have a critical role. Here, we examine the reinforcing effects of several compounds that vary with respect to intrinsic efficacy at α2, α3, and α5 subunit-containing GABAA receptors but lack efficacy at α1 subunit-containing GABAA receptors (‘α1-sparing compounds'): MRK-623 (functional selectivity for α2/α3 subunit-containing receptors), TPA023B (functional selectivity for α2/α3/α5 subunit-containing receptors), and TP003 (functional selectivity for α3 subunit-containing receptors). The reinforcing effects of the α1-sparing compounds were compared with those of the non-selective benzodiazepine receptor partial agonist MRK-696, and non-selective benzodiazepine receptor full agonists, midazolam and lorazepam, in rhesus monkeys trained to self-administer midazolam or cocaine, under a progressive-ratio schedule of intravenous (i.v.) drug injection. The α1-sparing compounds were self-administered significantly above vehicle levels in monkeys maintained under a midazolam baseline, but not under a cocaine baseline over the dose ranges tested. Importantly, TP003 had significant reinforcing effects, albeit at lower levels of self-administration than non-selective benzodiazepine receptor agonists. Together, these results suggest that α1 subunit-containing GABAA receptors may have a role in the reinforcing effects of benzodiazepine-type compounds in monkeys with a history of stimulant self-administration, whereas α3 subunit-containing GABAA receptors may be important mediators of the reinforcing effects of benzodiazepine-type compounds in animals with a history of sedative-anxiolytic/benzodiazepine self-administration. PMID:23303046

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

    DEFF Research Database (Denmark)

    Eden, Marie; Schjønning, Per; Møldrup, Per

    2011-01-01

    OF had larger porosity than that from treatment MF. Treatment P eliminated this difference and significantly reduced the volume of macropores. This interaction between soil organic matter content and mechanical impact was also reflected in the gas diffusion data. Specific air permeability was mainly......). Water retention, air permeability and gas diffusivity were determined at )100 hPa in both years and for a range of water potentials in one of the years. The continued addition of animal manure had increased OC, BC, and Chot compared with the soil receiving only mineral fertilizer. Soil under treatment....... Our studies indicate that organic manure increases soil porosity, but compaction reduces the related gas exchange effects to the level of compacted soils receiving mineral fertilizer....

  17. Water management in the oil sands industry

    Energy Technology Data Exchange (ETDEWEB)

    Pauls, R. [Syncrude Canada Ltd., Fort McMurray, AB (Canada)

    2004-07-01

    Water management issues at Alberta's 4 oil sand deposits were discussed. The 4 deposits include the Peace River, Athabasca, Wabasca and Cold Lake deposits, with the Athabasca deposit being the largest and the only surface-mineable deposit. Large quantities of water are needed to extract bitumen from oil sands. This paper addressed water volume withdrawal from the Athabasca River, the primary source of water for the surface-mining oil sands industry. It also addressed Muskeg River watershed integrity, quality of water withdrawn from reclaimed landscapes, groundwater contamination, and ecological viability of end-pit lakes. Currently, half of Syncrude's oil sand is transported from mine to extraction plant by conveyor belts. The other half is pipelined as a warm water slurry. By 2005, all transport will be by pipeline. The oil sand is mixed with hot water, steam and surfactants to condition it for extraction. Seventy-nine per cent of the water used by Syncrude is recycled water and the remainder comes from the Athabasca River. Syncrude diverts 2.5 to 3 barrels of water from the Athabasca River for every barrel of oil produced. This paper discussed the in-stream flow needs of the Athabasca River based on protection of aquatic ecosystems. Flow needs are addressed by the Cumulative Effects Management Association (CEMA). The paper states that the proportion of annual flow withdrawn from the Athabasca River is too low to have a significant impact on aquatic systems, but the main concern lies in water use during low flow periods, typically during the winter months. Developers will likely come under pressure to develop off-site reservoirs to store water for use during these low-flow periods. tabs., figs.

  18. Imaging of Acoustic Waves in Sand

    Energy Technology Data Exchange (ETDEWEB)

    Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall

    2003-08-01

    There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.

  19. Truncated G protein-coupled mu opioid receptor MOR-1 splice variants are targets for highly potent opioid analgesics lacking side effects.

    Science.gov (United States)

    Majumdar, Susruta; Grinnell, Steven; Le Rouzic, Valerie; Burgman, Maxim; Polikar, Lisa; Ansonoff, Michael; Pintar, John; Pan, Ying-Xian; Pasternak, Gavril W

    2011-12-06

    Pain remains a pervasive problem throughout medicine, transcending all specialty boundaries. Despite the extraordinary insights into pain and its mechanisms over the past few decades, few advances have been made with analgesics. Most pain remains treated by opiates, which have significant side effects that limit their utility. We now describe a potent opiate analgesic lacking the traditional side effects associated with classical opiates, including respiratory depression, significant constipation, physical dependence, and, perhaps most important, reinforcing behavior, demonstrating that it is possible to dissociate side effects from analgesia. Evidence indicates that this agent acts through a truncated, six-transmembrane variant of the G protein-coupled mu opioid receptor MOR-1. Although truncated splice variants have been reported for a number of G protein-coupled receptors, their functional relevance has been unclear. Our evidence now suggests that truncated variants can be physiologically important through heterodimerization, even when inactive alone, and can comprise new therapeutic targets, as illustrated by our unique opioid analgesics with a vastly improved pharmacological profile.

  20. The Lack of Cytotoxic Effect and Radioadaptive Response in Splenocytes of Mice Exposed to Low Level Internal β-Particle Irradiation through Tritiated Drinking Water in Vivo

    Directory of Open Access Journals (Sweden)

    Matthew Flegal

    2013-12-01

    Full Text Available Health effects of tritium, a β-emitter and a by-product of the nuclear industry, is a subject of significant controversy. This mouse in vivo study was undertaken to monitor biological effects of low level tritium exposure. Mice were exposed to tritiated drinking water (HTO at 10 KBq/L, 1 MBq/L and 20 MBq/L concentrations for one month. The treatment did not result in a significant increase of apoptosis in splenocytes. To examine if this low level tritium exposure alters radiosensitivity, the extracted splenocytes were challenged in vitro with 2 Gy γ-radiation, and apoptotic responses at 1 and 24 h were measured. No alterations in the radiosensitivity were detected in cells from mice exposed to tritium compared to sham-treated mice. In contrast, low dose γ-irradiation at 20 or 100 mGy, resulted in a significant increase in resistance to apoptotic cell death after 2 Gy irradiation; an indication of the radioadaptive response. Overall, our data suggest that low concentrations of tritium given to mice as HTO in drinking water do not exert cytotoxic effect in splenocytes, nor do they change cellular sensitivity to additional high dose γ-radiation. The latter may be considered as the lack of a radioadaptive response, typically observed after low dose γ-irradiation.

  1. STUDY ON HOT SAND COOLING EQUIPMENT WITH DAMPING SAND CASCADE AND VERTICAL SPOUTED-FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    L.C. Wang; F. Wang; X.H. You

    2005-01-01

    A new kind of hot sand cooling equipment with vertical spouted-fluidized bed is developed in this paper. It is similar to the traditional horizontal vibrating fluidized boiling cooler in principle but different from it in structure. The processing principle of the cooler is analyzed. The influence of main structural and processing parameters on the cooling effect and its mechanism are researched. Other characteristics of the cooler are discussed also. Experiment results show that the cooling efficiency η is equal to or larger than 83%, the temperature of output sand is less than 40℃ with the temperature of input sand is about between 80 and 90℃, and the productivity is 5t/(h·m)

  2. Sand engine quells the coast's hunger for sand

    NARCIS (Netherlands)

    Van Dijk, T.

    2012-01-01

    An artificial peninsula at Ter Heijde is designed to feed the coast with sediment. Scientists are investigating whether this kind of sand engine could be the Netherlands’ answer to rising sea levels.

  3. Sand engine quells the coast's hunger for sand

    NARCIS (Netherlands)

    Van Dijk, T.

    2012-01-01

    An artificial peninsula at Ter Heijde is designed to feed the coast with sediment. Scientists are investigating whether this kind of sand engine could be the Netherlands’ answer to rising sea levels.

  4. EFFECT OF STATINS ALONE VERSUS STATINS PLUS EZETIMIBE ON CAROTID ATHEROSCLEROSIS IN TYPE 2 DIABETES: THE SANDS TRIAL

    Science.gov (United States)

    Fleg, Jerome L.; Mete, Mihriye; Howard, Barbara V.; Umans, Jason G.; Roman, Mary J.; E, Robert; Ratner, MD; Silverman, Angela; Galloway, James M.; Henderson, Jeffrey A.; Weir, Matthew R.; Wilson, Charlton; Stylianou, Mario; Howard, Wm. James

    2009-01-01

    Objective This secondary analysis from the Stop Atherosclerosis in Native Diabetics Study examines the effects of lowering low-density lipoprotein cholesterol (LDL-C) with statins alone versus statins plus ezetimibe (E) on common carotid artery intimal medial thickness (CIMT) in patients with type 2 diabetes and no prior cardiovascular event. Background It is unknown whether the addition of E to statin therapy affects subclinical atherosclerosis. Methods Within an aggressive group (target LDL-C ≤70mg/dL; non-high-density lipoprotein [non-HDL]-C ≤40 yrs receiving statins plus E versus statins alone. CIMT changes in both aggressive subgroups were compared with changes in the standard subgroups (target LDL-C ≤<100mg/dL; non-HDL-C ≤ 130 mg/dL; SBP ≤130mmHg). Results Mean (95%CI) LDL-C was reduced by 31 (23, 37)mg/dL and 32 (27, 38)mg/dL in the aggressive group receiving statins plus E and statins alone, respectively, compared with changes of 1 (−3, 6) mg/dL in the standard group (p<0.0001 vs both aggressive subgroups. Within the aggressive group, mean IMT at 36mos regressed from baseline similarly in the E (−.025 [−05,.003] mm) and non-E subgroups (−.012 [−.03,.008] mm) but progressed in the standard treatment arm (0.039 [0.02, 0.06] mm), intergroup p<0.0001. Conclusions Reducing LDL-C to aggressive targets resulted in similar regression of CIMT in patients who attained equivalent LDL-C reductions from a statin alone or statin plus E. CIMT increased in those achieving standard targets. PMID:19095139

  5. Drawing a line in the sand: Effectiveness of off-highway vehicle management in California's Sonoran desert

    Science.gov (United States)

    Custer, Nathan; Defalco, Lesley A.; Nussear, Kenneth E.; Esque, Todd C.

    2017-01-01

    Public land policies manage multiple uses while striving to protect vulnerable plant and wildlife habitats from degradation; yet the effectiveness of such policies are infrequently evaluated, particularly for remote landscapes that are difficult to monitor. We assessed the use and impacts of recreational vehicles on Mojave Desert washes (intermittent streams) in the Chemehuevi Desert Wildlife Management Area (DWMA) of southern California. Wash zones designated as open and closed to off-highway vehicle (OHV) activity were designed in part to protect Mojave desert tortoise (Gopherus agassizii) habitat while allowing recreation in designated areas. OHV tracks were monitored in washes located near access roads during winter and early spring holidays – when recreation is typically high – and at randomly dispersed locations away from roads. Washes near access roads had fewer vehicle tracks within closed than open zones; further away from roads, OHV tracks were infrequent and their occurrence was not different between wash designations. Washes were in better condition in closed zones following major holidays as indicated by less vegetation damage, presence of trash, and wash bank damage. Furthermore, the frequency of washes with live tortoises and their sign was marginally greater in closed than open wash zones. Collectively, these results suggest that low impacts to habitats in designated closed wash zones reflect public compliance with federal OHV policy and regulations in the Chemehuevi DWMA during our study. Future monitoring to contrast wash use and impacts during other seasons as well as in other DWMAs will elucidate spatial and temporal patterns of recreation in these important conservation areas.

  6. Fresh groundwater resources in a large sand replenishment

    Science.gov (United States)

    Huizer, Sebastian; Oude Essink, Gualbert H. P.; Bierkens, Marc F. P.

    2016-08-01

    The anticipation of sea-level rise and increases in extreme weather conditions has led to the initiation of an innovative coastal management project called the Sand Engine. In this pilot project a large volume of sand (21.5 million m3) - also called sand replenishment or nourishment - was placed on the Dutch coast. The intention is that the sand is redistributed by wind, current, and tide, reinforcing local coastal defence structures and leading to a unique, dynamic environment. In this study we investigated the potential effect of the long-term morphological evolution of the large sand replenishment and climate change on fresh groundwater resources. The potential effects on the local groundwater system were quantified with a calibrated three-dimensional (3-D) groundwater model, in which both variable-density groundwater flow and salt transport were simulated. Model simulations showed that the long-term morphological evolution of the Sand Engine results in a substantial growth of fresh groundwater resources, in all adopted climate change scenarios. Thus, the application of a local sand replenishment could provide coastal areas the opportunity to combine coastal protection with an increase of the local fresh groundwater availability.

  7. Investigations on Several Mechanical Problems in Windblown Sand Movement

    Institute of Scientific and Technical Information of China (English)

    Zheng Xiaojing

    2007-01-01

    It is very necessary for the investigation on mechanism of windblown sand movement to understand and find out effective measures of preventing and reducing danger of windblown sands, which also deals with some general characters and hot spots in the scientific forelands, such as multi-scale problems, interactions among multi-physical-fields, randomness and nonlinearity as well as complex systems. In recent years, a series of experiments in wind tunnels and theoretical modeling as well as computer simulation have been undertaken in the research group of environmental mechanics on windblown sand movement in Lanzhou University with the point of mechanical and geography intersecting view. Some original and essential progress has been achieved, which includes that the main regularities of charges on sand particles and the electric field in windblown sand flux and the effect of the electric field on the flux and the microwave propagation are revealed, and the evolution process of windblown sand flux under the mutual couple interactions among several physical fields are predicted as well as the main features of Aeolian sand ripples are simulated.

  8. Investigations on Several Mechanical Problems in Windblown Sand Movement

    Institute of Scientific and Technical Information of China (English)

    Xiaojing Zheng

    2006-01-01

    It is very necessary for investigation on mechanism of windblown sand movement to understand and find out effective measures of preventing and reducing windblown sand. This also deals with some general features and hot spots in the scientific forelands, such as multi-scale problems, interactions among multi-physical-fields, randomness and nonlinearity as well as complex systems. In recent years, a series of experiments in wind tunnels and theoretical modeling as well as computer simulation have been taken by our research group (the Laboratory of Environmental Mechanics on Windblown Sand Movement in Lanzhou University) in a cross-disciplinary (mechanics and geography) viewpoint. Several original and essential studies were explored such as the main regularities of charges on sand particles, the mechanisms of electric field in windblown sand flux, the effects induced by the electric field on the flux, the microwave propagations, the evolution process of windblown sand flux under mutual couple interactions among several physical fields, and the simulation of the main features of Aeolian sand ripples.

  9. Spectroscopic characterization of a Nigerian standard sand: Igbokoda sand

    CSIR Research Space (South Africa)

    Ojuri, OO

    2017-01-01

    Full Text Available the Middle Ordovician St. Peter Sandstone near Ottawa, Illinois, had been picked by the American Society for Testing and Materials (ASTM) as the reference sand to employ in testing cement and strength of concrete [9]. To the best of our knowledge... and magnetic resonance spectroscopic techniques due to its importance in cement, geotechnical/geo-environmental research in Nigeria. This should halt importation of standard silica sand for mortar and concrete testing...

  10. The effect of a natural water-movement related disturbance on the structure of meiofauna and macrofauna communities in the intertidal sand flat of Rocas Atoll (NE, Brazil)

    Science.gov (United States)

    Netto, S. A.; Attrill, M. J.; Warwick, R. M.

    1999-12-01

    Rocas, the only atoll in the South Atlantic, is located 266 km off the northeast Brazilian coast. Spatial patterns in community structure of meiofauna, particularly nematodes, and macrofauna were examined along a transect through the sediment path from windward to leeward of the Rocas Atoll sand flat. Differences in benthic community structure between four zones of the sand flat were found to be significant and related to the major local processes of carbonate-grain transport and sedimentation. Both meiobenthic and macrobenthic assemblages were significantly more diverse and abundant within the sediment inflow zone (the initial part of the detrital path of Rocas sand flat) than in the other zones, where a clear impoverishment of benthic invertebrates occurred. This first study of the benthos of an intertidal sand flat over a reef island in the Atlantic showed that the meiofauna is numerically dominated by the nematodes Metoncholainus sp. 1 (Oncholaimidae) and Epsilonema sp. 1 (Epsilonematidade), whilst the macrofauna is largely dominated by oligochaetes and large Oncholaimidae nematodes. Analysis of the species composition, trophic structure and abundance of both the meiobenthos and the macrobenthos revealed an impoverished community subjected to an intense water-movement disturbance.

  11. Physico-chemical properties of quartz from industrial manufacturing and its cytotoxic effects on alveolar macrophages: The case of green sand mould casting for iron production.

    Science.gov (United States)

    Di Benedetto, Francesco; Gazzano, Elena; Tomatis, Maura; Turci, Francesco; Pardi, Luca A; Bronco, Simona; Fornaciai, Gabriele; Innocenti, Massimo; Montegrossi, Giordano; Muniz Miranda, Maurizio; Zoleo, Alfonso; Capacci, Fabio; Fubini, Bice; Ghigo, Dario; Romanelli, Maurizio

    2016-07-15

    Industrial processing of materials containing quartz induces physico-chemical modifications that contribute to the variability of quartz hazard in different plants. Here, modifications affecting a quartz-rich sand during cast iron production, have been investigated. Composition, morphology, presence of radicals associated to quartz and reactivity in free radical generation were studied on a raw sand and on a dust recovered after mould dismantling. Additionally, cytotoxicity of the processed dust and ROS and NO generation were evaluated on MH-S macrophages. Particle morphology and size were marginally affected by casting processing, which caused only a slight increase of the amount of respirable fraction. The raw sand was able to catalyze OH and CO2(-) generation in cell-free test, even if in a lesser extent than the reference quartz (Min-U-Sil), and shows hAl radicals, conventionally found in any quartz-bearing raw materials. Enrichment in iron and extensive coverage with amorphous carbon were observed during processing. They likely contributed, respectively, to increasing the ability of processed dust to release CO2- and to suppressing OH generation respect to the raw sand. Carbon coverage and repeated thermal treatments during industrial processing also caused annealing of radiogenic hAl defects. Finally, no cellular responses were observed with the respirable fraction of the processed powder.

  12. A Comparative Study on Sand Transport Modeling for Horizontal Multiphase Pipeline

    Directory of Open Access Journals (Sweden)

    Kan Wai Choong

    2014-02-01

    Full Text Available Presence of sand causes adverse effects on hydrocarbon production, pipeline erosion and problems at wellbore. If the problems persist, production may be stopped and delayed. This imposes workover cost. Hence, operating expenses increase and revenue reduces. There is no explicit calculation algorithm for sand transportation modeling readily available in flow simulators. Therefore, this study aims to develop an Excel-based spreadsheet on sand transportation to predict sand critical velocity and onset of sand deposition based on published literature. The authors reviewed nine sand transportation models in pipelines and made comparisons on the selected models based on various criteria. Four of which were then developed into a sand modeling spreadsheet. The four models are the Turian et al. (1987, Oudeman (1993, Stevenson et al. (2002b Model and Danielson (2007. The spreadsheet presently focuses on sand production prediction in horizontal two-phase flow. The Danielson model can predict sand hold up while the other models estimate grain size transportable and critical velocity of sand. Flowing pipeline properties, sand properties and results of simulations like using OLGA (for flow rate, velocity and superficial velocity of different phases are necessary inputs of the spreadsheet. A user selects any model based on different operating conditions or user preference. The spreadsheet was validated by comparing data extracted from the research papers. Sensitivity analyses can also be performed with the spreadsheet by manipulating the parameters such as grain size and flow rate. This review is useful for flow simulators’ development to include sand transport modeling.

  13. Reclaimability of the spent sand mixture – sand with bentonite – sand with furfuryl resin

    Directory of Open Access Journals (Sweden)

    J. Dańko

    2011-04-01

    Full Text Available Introduction of new binding materials and new technologies of their hardening in casting moulds and cores production requires theapplication of reclamation methods adequate to their properties as well as special devices realizing tasks. The spent sands circulationsystem containing the same kind of moulding and core sands is optimal from the point of view of the expected reclamation results.However, in the face of a significant variability of applied technologies and related to them various reclamation methods, the need - of theobtained reclamation products assessment on the grounds of systematic criteria and uniform bases – arises, with a tendency of indicatingwhich criteria are the most important for the given sand system. The reclaimability results of the mixture of the spent moulding sand withGeko S bentonite and the spent core sand with the Kaltharz 404U resin hardened by acidic hardener 100 T3, are presented in the paper.Investigations were performed with regard to the estimation of an influence of core sands additions (10 –25% on the reclaimed materialquality. Dusts and clay content in the reclaim, its chemical reaction (pH and ignition loss were estimated. The verification of the reclaiminstrumental assessment was performed on the basis of the technological properties estimation of moulding sand with bentonite, where the reclaimed material was used as a matrix.

  14. Failure of adrenal corticosterone production in POMC-deficient mice results from lack of integrated effects of POMC peptides on multiple factors.

    Science.gov (United States)

    Karpac, Jason; Czyzewska, Katarzyna; Kern, Andras; Brush, Richard S; Anderson, Robert E; Hochgeschwender, Ute

    2008-08-01

    Production of corticosteroids from the adrenal gland is a multistep process in which corticosterone is enzymatically processed from its precursor cholesterol. The main hormone regulating the production of corticosterone is the proopiomelanocortin (POMC)-derived adrenocorticotropic hormone (ACTH). Adrenals of POMC-deficient (POMC(-/-)) mice do not produce corticosterone either at basal levels or in response to acute stimulation with ACTH. However, pharmacological amounts of ACTH delivered continuously elicit corticosterone production over time. To define the relative effects of ACTH on individual factors involved in corticosterone production, parameters of adrenal cholesterol metabolism and steroidogenesis were examined in POMC(-/-) mice compared with wild-type and ACTH-treated mutant mice. POMC(-/-) adrenals lack cholesterol esters (CE); adrenal CE is restored with ACTH treatment. However, discontinuation of ACTH treatment stops corticosterone production despite the presence of adrenal CE. Failure of corticosterone production by POMC(-/-) adrenals occurs despite the constitutive presence of transcripts of genes required for cholesterol metabolism and steroidogenesis. Levels of key proteins involved in selective cholesterol uptake and steroidogenesis were attenuated; ACTH treatment increased these protein levels, most significantly those of the receptor responsible for selective uptake of CE, scavenger receptor class B, type I (SR-BI). Our studies reveal that failure of corticosterone production of POMC(-/-) adrenal glands and its pharmacological reconstitution by ACTH are not mediated by any one individual protein, but rather as an integrated effect on multiple factors from import of the substrate cholesterol to its conversion to corticosterone.

  15. Postoperative Perfection: Ceiling Effects and Lack of Discrimination With Both SRS-22 and -24 Outcomes Instruments in Patients With Adolescent Idiopathic Scoliosis.

    Science.gov (United States)

    Bastrom, Tracey P; Bartley, Carrie; Marks, Michelle C; Yaszay, Burt; Newton, Peter O

    2015-12-01

    Review of a prospective database registry. To compare the Scoliosis Research Society (SRS)-22 and SRS-24 outcomes instruments in terms of scores, rate of ceiling effects, and discriminant ability in patients with pre- and postoperative adolescent idiopathic scoliosis. Despite improvements noted with the SRS-22, the SRS-24 is still occasionally used prospectively and for comparisons with previous studies reporting SRS-24 scores. Previous work has demonstrated that postoperative scores from the 2 versions are not interchangeable. A multicenter prospective registry of patients who underwent surgical correction of adolescent idiopathic scoliosis was queried for preoperative and 2-year postoperative SRS-22 and SRS-24 scores. Scores were compared between versions and ceiling effects were identified. Groups of deformity severity were created to evaluate discriminant ability. 829 patients were identified. The SRS-22 scores for pain and general function were significantly greater than SRS-24 scores (P self-image (P self-image domain was able to discriminate between large (29°+) and small (≤11°) residual curves (P < 0.05). Scores obtained by the SRS-22 and the SRS-24 are not translatable despite shared domains. Whereas both versions demonstrated preoperative discriminant ability, postoperative discrimination of residual deformity is lacking in both. Patient-reported outcomes of treatment are crucial in advancing treatment, and improvement in the ability to assess subjective outcomes is essential. 3.

  16. 戈壁地区公路防沙措施防沙效应的风洞试验%Wind Tunnel Experiment of the Effect of Sand Prevention Measures along Gobi Highway

    Institute of Scientific and Technical Information of China (English)

    尤全刚; 薛娴; 王涛; 赵发章; 张伟民; 刘光琇; 俎瑞平; 韩邦帅; 连富铖

    2011-01-01

    以穿越河西走廊西部戈壁荒漠的嘉峪关至安西一级公路为研究对象,基于风洞模拟试验,针对不同类型公路路基横断面和防护措施设计模型,采用粒子图像测速系统,研究模型的流场变化,进而探讨戈壁公路风沙危害形成机理及防沙措施.研究结果表明:①由于研究区内风沙活动以不饱和风沙流为主,携沙风对公路路基掏蚀、磨蚀严重,需要对路基边坡进行有效砌护;②为了在公路表面形成输沙通道,中央隔离带地表与行车路面应保持同一高度,隔离带采用空隙度大于30%的疏透型;③在公路两侧沙源丰富地段,公路边坡的坡角应小于40°,并且取消防洪沟,以防止沟内积沙;④在沙源丰富地区,公路两侧由外到内依次铺设草方格、覆盖砾石、设置积沙沟的防沙带,可以减少气流中的含沙量,阻止流沙上路,有效解决公路风沙危害问题.%Wind erosion and sand sediment are two main problems affecting highways in Gobi area of Western China. This paper investigated the effect of sand prevention measures on highways in Gobi area by simulating different highway segments and sand prevention designs in wind tunnel and surveying fields by Particle Image Velocimetry. The wind tunnel experiment results indicated that unsaturated blown sand flow played a dominant role in the sapping and abrasion of highway cross section and some effective protection measures should be adopted to improve the protection of embankment slope of highway. In addition, the surface of isolation belts should be kept the same height as the driving pavement to form a sediment transportation pathway. The voidage of isolation belts should be more than 30%. For reducing sand deposition near highway, highway slope angle should be kept less than 40°. The flood discharge trench should be removed and some other protection measures should be adopted in some areas with abundant sand source. The experimental results

  17. Research and practice of the impulse sand fracturing technology

    Directory of Open Access Journals (Sweden)

    Bin Qian

    2015-10-01

    Full Text Available With the deep development of tight sand gas reservoirs, problems such as short stable production period and quick production decline of gas wells after fracturing have become increasingly prominent. Consequently, there is an increasing demand for the effective penetration and conductivity of artificial fractures. Impulse sand fracturing technology introduces a concept of discrete multilayer sanding inside fractures; joint application of pulse blender which can be switched at high frequency, intensive multi-cluster perforation and special fibrous material made it possible to ensure the flow stability of proppant slug, and placement of nonuniformly-laid sand pinnacles and grooves, which markedly upgraded the capacity of the fracture conductivity to several orders of magnitude more than the conventional method. Laboratory engineering simulation evaluation and field test show that pre-fracturing reservoir evaluation, pulse time design and the optimization of degradable fiber and support equipment are the keys to the success of impulse sand fracturing. Compared with the conventional fracturing, this technique can effectively increase well production, decrease the volume of fracturing proppant, and lower sand plugging risks. An independent sand fracturing pilot test has been conducted in 6 layers of 3 wells for the first time in Block Tao 7 of the Sulige Gasfield, Ordos Basin, as a result, the average volume of fracturing proppant dropped by 28.3%, the average sand intensity dropped by 21.88%, and the post-fracturing average daily gas output increased by 26.8%. This technology provides an efficient and environmentally friendly reservoir stimulation option for tight sand gas reservoirs in China.

  18. Management recommendations: Sand Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Sand Lake National Wildlife Refuge, by a land use specialist. Recommendations, time frame and...

  19. Lack of detrimental effects of Bacillus thuringiensis Cry toxins on the insect predator Chrysoperla carnea: a toxicological, histopathological, and biochemical analysis.

    Science.gov (United States)

    Rodrigo-Simón, Ana; de Maagd, Ruud A; Avilla, Carlos; Bakker, Petra L; Molthoff, Jos; González-Zamora, Jose E; Ferré, Juan

    2006-02-01

    The effect of Cry proteins of Bacillus thuringiensis on the green lacewing (Chrysoperla carnea) was studied by using a holistic approach which consisted of independent, complementary experimental strategies. Tritrophic experiments were performed, in which lacewing larvae were fed Helicoverpa armigera larvae reared on Cry1Ac, Cry1Ab, or Cry2Ab toxins. In complementary experiments, a predetermined amount of purified Cry1Ac was directly fed to lacewing larvae. In both experiments no effects on prey utilization or fitness parameters were found. Since binding to the midgut is an indispensable step for toxicity of Cry proteins to known target insects, we hypothesized that specific binding of the Cry1A proteins should be found if the proteins were toxic to the green lacewing. In control experiments, Cry1Ac was detected bound to the midgut epithelium of intoxicated H. armigera larvae, and cell damage was observed. However, no binding or histopathological effects of the toxin were found in tissue sections of lacewing larvae. Similarly, Cry1Ab or Cry1Ac bound in a specific manner to brush border membrane vesicles from Spodoptera exigua but not to similar fractions from green lacewing larvae. The in vivo and in vitro binding results strongly suggest that the lacewing larval midgut lacks specific receptors for Cry1Ab or Cry1Ac. These results agree with those obtained in bioassays, and we concluded that the Cry toxins tested, even at concentrations higher than those expected in real-life situations, do not have a detrimental effect on the green lacewing when they are ingested either directly or through the prey.

  20. Isotropic Compression Behaviour of Fibre Reinforced Cemented Sand

    Directory of Open Access Journals (Sweden)

    Salahuddin

    2013-07-01

    Full Text Available Fibre-reinforced cemented sands have many applications in improving the response of soils. In this paper, an experimental investigation for the analysis of fiber-reinforced cemented sand in the framework of isotropic compression is presented. The experimental investigations were carried out using a high pressure triaxial apparatus having the capacity of 64 MPa of confining pressure. Tests have been conducted on Portaway sand specimens reinforced with randomly oriented discrete polypropylene fibers with different percentages of fiber and cement contents. Results are presented in the form of e-logp` curves as well as SEM (Scanning Electron Microscopy micrographs. The effects of the addition of fibre in sand and cemented sand for different initial void ratios were investigated. The results demonstrate that the influence of fibre is not significant in both cemented and uncemented sand during the isotropic compression sta