Atmospheric dust accession in South-Eastern Australia.

Soil Research ◽  
1971 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
PH Walker ◽  
AB Costin
Keyword(s):  
Particle Size ◽  
Organic Content ◽  
Alpine Soils ◽  
The Past ◽  
Eastern Australia ◽  
Australian Alps ◽  
Central Regions ◽  
Median Diameter ◽  
Strong Winds ◽  
High Organic Content

Reddish dust, transported by strong winds from the dry central regions of Australia, is periodically deposited in the humid eastern part of the continent. Dust sampled in snow on the Australian alps during 1968 is comparable in amount with accession reported earlier in the 1900's in New Zealand and Melbourne. The dust reported here has a median diameter of 4 pm, relatively high organic content, and mineralogy in the less than 2 pm fraction dominated by illite and kaolin. The rate of dust accession during the past was probably sufficient to have modified alpine soils. In particular, snow patch soils have a particle size and mineralogy consistent with dust enrichment. A much lower rate of dust accession seems to occur at present in Canberra on the Southern Tablelands.

The influence of aeolian dust deposits on alpine soils in south-eastern Australia

Soil Research ◽  
2001 ◽  
Vol 39 (1) ◽  
pp. 81 ◽  
Author(s):  
Stuart William Johnston
Keyword(s):  
Particle Size ◽  
National Park ◽  
Clay Mineralogy ◽  
Exchangeable Cations ◽  
Soil Profiles ◽  
Alpine Soils ◽  
Aeolian Dust ◽  
Eastern Australia ◽  
Aeolian Sediment ◽  
Dust Deposits

Aeolian sediment collected from 2 locations across the ‘Main Range’ of Kosciuszko National Park, along with a series of soil profiles that were analysed for particle size, were used as a baseline from which to estimate the effects of aeolian sedimentation in this region. Laboratory analysis of the soil profiles indicated that the properties of the surface horizons of the alpine humus soils were heavily influenced by aeolian dust accumulation; however, the sub-surface horizons were mainly derived from the natural bedrock. The surface and subsurface horizons differed in texture bulk density, pH, electrical conductivity, exchangeable cations, and clay mineralogy. This study confirmed that the snow patch meadow soils exhibited particle size and mineralogy consistent with dust enrichment, with distinct bands being found in some profiles.

Perfluorooctanoic acid (PFOA) uptake by alfalfa (Medicago sativa) and bioavailability in Sprague-Dawley rats

2020 ◽  
Author(s):  
Sara J Lupton ◽  
Heldur Hakk
Keyword(s):  
Wastewater Treatment Plants ◽  
Perfluorooctanoic Acid ◽  
Organic Content ◽  
Consumer Products ◽  
Withdrawal Period ◽  
Sprague Dawley ◽  
Animal Products ◽  
The Past ◽  
Sprague Dawley Rats ◽  
High Organic Content

Perfluorooctanoic acid (PFOA) is a perfluorinated alkyl substance (PFAS) used as surfactant in a wide variety of industrial and consumer products. Over the past decade, concern has increased over the presence of PFOA in biosolids from wastewater treatment plants used as fertilizer on agricultural lands having the potential to enter the food chain. In this study, the uptake of 14C-PFOA from soil by alfalfa was determined, as was the bioavailability of 14C-PFOA-incurred into alfalfa in Sprague-Dawley rats. Alfalfa leaves accumulated PFOA to as high as 4-5 µg/g of dry leaf, approximately 10 times higher than accumulation in the stem. Alfalfa was ground for feeding to 15 female Sprague-Dawley rats (175-200 g). Animals within metabolism cages were fed 10 g of feed (6 g alfalfa + 4 g ground rat chow) twice a day for 14 days (equivalent to 50 ug-PFOA/kg/day). At the end of the feeding period, rats (n=3) were sacrificed at withdrawal days of 0, 3, 7, 11, and 14 days. During the feeding and withdrawal phases, urine and feces were collected daily. At sacrifice, blood, liver, kidney, adipose, muscle, skin, brain, heart, adrenals, spleen, lungs, and thymus were removed and assayed for 14C-PFOA by combustion and LSC analysis. Rats eliminated 72.8 ± 3.4% of the total dose via urine at 14-days, but urinary radioactivity fell below the LOD by day 3 of the withdrawal period. Fecal elimination was 6.5 ± 1.2 % of the dose and fell below the LOD by 2 days of withdrawal. The rapid and high elimination via urine indicates that a majority of the dose was absorbed. The uptake of PFOA into alfalfa was low from a high organic content soil, however, PFOA was highly bioavailable from the alfalfa when used as a feed component for rats. This study provides data for regulators investigating PFOA bioavailability and disposition in animals or animal products exposed to contaminated feed.

scholarly journals Efektivitas Biji Kelor sebagai Koagulan Alami pada Pengolahan Limbah Cair Tahu Melalui Proses Anaerobik-Aerobik

FLUIDA ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 30-37
Author(s):  
Laily Isna Ramadhani ◽  
Yurike Dwiayu Rahmaningsi ◽  
Nanda Ravenia Amanda ◽  
Herawati Budiastuti
Keyword(s):  
Particle Size ◽  
Organic Content ◽  
Optimum Dose ◽  
Optimum Size ◽  
Natural Coagulant ◽  
Turbidity Level ◽  
High Organic Content

ABSTRAK   Limbah cair tahu merupakan salah satu limbah cair dengan kandungan organik yang tinggi dan berpotensi merusak lingkungan. Pada penelitian ini digunakan dua metode pengolahan dengan mengkombinasikan metode pengolahan biologi dan proses koagulasi-flokulasi menggunakan koagulan alami, biji kelor. Tujuan dari penelitian ini adalah mempelajari pengaruh dosis dan ukuran partikel koagulan terbaik. Dosis biji kelor divariasikan dari 1.000, 2.000, 3.000, dan 4.000 ppm. Dosis terbaik digunakan untuk menentukan ukuran partikel koagulan terbaik dengan variasi ukuran 250, 500, 1.000, dan 2.000 µm. Hasil penelitian menunjukkan bahwa dosis biji kelor terbaik untuk metode 1 (aerobik dan koagulasi flokulasi) adalah 2.000 ppm dan untuk metode 2 (kombinasi anaerobik-aerobik dan koagulasi flokulasi) adalah 4.000 ppm. Ukuran partikel terbaik yaitu 500 µm untuk kedua metode dengan efisiensi penurunan kekeruhan sebesar 94,57% untuk efluen metode 1 dan 78,28% untuk efluen metode 2.   Kata kunci: Limbah cair tahu, biji kelor,koagulan alami,  koagulasi- flokulasi   ABSTRACT   Tofu wastewater is one of the pollutant wastewater that potentially cause the serious damage to the environment due to its high organic content. The combination of biology method in the help of microorganism and coagulation-flocculation method using kelor seed were applied in this study. This research aims were determining the best dose and the optimum size of coagulant. Doses variation were 1,000, 2,000, 3,000 and 4,000 ppm of coagulant. The best dose resulted would be used to determine the optimum size of coagulant by variating 250, 500, 1,000 and 2,000 µm. The result showed that 2,000 ppm was the best coagulant dose for the first method (aerobic and coagulation-flocculation method) and 4,000 ppm was the optimum dose for the second method (combination of anaerobic-aerobic and coagulation-flocculation method). 500 µm was determined as the optimum particle size of the coagulant for both methods with % removal turbidity level were 94,57% for the first method and 78,28% for the second method.   Keywords:Tofu wastewater, kelor seed, natural coagulant, coagulation-flocculation

Electroacoustic Study of n-Hexadecane/Water Emulsions

2001 ◽  
Vol 54 (8) ◽  
pp. 503 ◽  
Author(s):  
Linggen Kong ◽  
James K. Beattie ◽  
Robert J. Hunter
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Volume Fraction ◽  
Sodium Dodecyl ◽  
Surfactant Solution ◽  
Minimum Size ◽  
Water Mixture ◽  
Concentrated Suspensions ◽  
Minimum Concentration ◽  
Median Diameter

n-Hexadecane-in-water emulsions were investigated by electroacoustics using a prototype of an AcoustoSizer-II apparatus. The emulsions were formed by passing the stirred oil/water mixture through a homogenizer in the presence of sodium dodecyl sulfate (SDS) at natural pH (6–7). With increasing oil-volume fraction, the particle size increased linearly after 5 and also after 20 passages through the homogenizer, suggesting that surface energy was determining particle size. For systems in which the surfactant concentration was limited, the particle size after 20 passages approached the value dictated by the SDS concentration. With ample surfactant present, the median diameter was a linear function of the inverse of the total energy input as measured by the number of passes. There was, however, a limit to the amount of size reduction that could be achieved in the homogenizer, and the minimum size was smaller at smaller volume fractions. Dilution of the emulsion with a surfactant solution of the same composition as the water phase had a negligible effect on the particle size and changed the zeta potential only slightly. This confirms results from previous work and validates the equations used to determine the particle size and zeta potential in concentrated suspensions. The minimum concentration of SDS that could prevent the emulsion from coalescing for the system with 6% by volume oil was 3 mM. For this dilute emulsion, the particle size decreased regularly with an increase in SDS concentration, but the magnitude of the zeta potential went through a strong maximum at intermediate surfactant concentrations.

Water retention in Australian soils. 2.* Prediction using particle size, bulk density, and other properties

Soil Research ◽  
1996 ◽  
Vol 34 (5) ◽  
pp. 679 ◽  
Author(s):  
Z Paydar ◽  
HP Cresswell
Keyword(s):  
Particle Size ◽  
Bulk Density ◽  
Soil Water ◽  
Multiple Regression ◽  
Empirical Relationship ◽  
Organic Matter Content ◽  
Matter Content ◽  
Point Method ◽  
Eastern Australia ◽  
The One

Different approaches were investigated for estimating the parameters in the Campbell soil water characteristic (SWC) equation from soil attributes such as particle size distribution (PSD), bulk density, and organic matter content. Predicted soil water characteristics were compared with measured values for soils of the wheatbelt of south-eastern Australia. A method of prediction is proposed incorporating an empirical relationship for estimating the slope of the SWC from the slope of the cumulative PSD. A power-law form is assumed for both the SWC and PSD functions. One measured SWC point is then used to locate and thus define the SWC curve. When SWC points predicted with this 'one-point' method were compared with measured values, the mean absolute value of the difference between each measured and predicted SWC point was 0.016 m3/m3 for the Geeves data and 0.027 m3/m3 for the Forrest data. Eight sets of predictive equations, previously developed using multiple regression analysis, were also evaluated. Whilst the equations predicted the slope of the SWC curves reasonably well, predictions of the air entry potential were poor. Although less accurate, the equations developed by multiple regression are less demanding in data requirement compared with alternative SWC prediction methods. The one-point method gave better predictions than the multiple regression approach but was less accurate than the 'two-point' method proposed in the first paper in this series. The one-point method should be considered where PSD data and 1 measured SWC point are available. In most other circumstances it will be more accurate and cost-effective to measure 2 SWC points to define the soil water characteristic function (the two-point method).* Part I, Aust. J. Soil Res., 1996, 34, 195–212.

Tape Casting of BaTiO3

1984 ◽  
Vol 40 ◽  
Author(s):  
J. B. Blum ◽  
W. R. Cannon
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Glass Plate ◽  
Tape Casting ◽  
Phosphate Ester ◽  
Powder Particle Size ◽  
Drying Method ◽  
Ultrasonic Dispersion ◽  
The Past

AbstractFor the past two years we have been investigating the tape casting of BaTiO3 Specifically we have been interested in developing a useful tape casting formulation and procedure and in studying the effects of powder particle size distribution and dispersion processes on the forming of BaTiO3 tapes.The formulation we have developed is non-aqueous. An MEKethanol mixture is the solvent and an acrylic binder is used. Two dispersants are being used, a phosphate ester and Menhaden fish oil. Ultrasonic dispersion was found to be effective in breaking up weak powder agglomerates. We have found it important to add the dispersant before adding other organic components to obtain the best dispersion and strongest tapes. The drying method is also important to tape strength. The strongest tapes resulted when the tape was removed from the glass plate soon after casting. We have also demonstrated that for forming purposes a wide particle size distribution is preferred.

scholarly journals A Gentle Sedimentation Process for Size-Selecting Porous Silicon Microparticles to Be Used for Drug Delivery Via Fine Gauge Needle Administration

Silicon ◽  
2020 ◽  
Author(s):  
Elida Nekovic ◽  
Catherine J. Storey ◽  
Andre Kaplan ◽  
Wolfgang Theis ◽  
Leigh T. Canham
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Porous Silicon ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Agglomeration ◽  
Gas Generation ◽  
Intravitreal Drug Delivery ◽  
Median Diameter ◽  
Experimental Values

AbstractBiodegradable porous silicon (pSi) particles are under development for drug delivery applications. The optimum particle size very much depends on medical use, and microparticles can outperform nanoparticles in specific instances. Here we demonstrate the ability of sedimentation to size-select ultrasmall (1–10 μm) nanoporous microparticles in common solvents. Size tunability is quantified for 1–24 h of sedimentation. Experimental values of settling times in ethanol and water are compared to those calculated using Stokes’ Law. Differences can arise due to particle agglomeration, internal gas generation and incomplete wetting. Air-dried and supercritically-dried pSi powders are shown to have, for example, their median diameter d (0.5) particle sizes reduced from 13 to 1 μm and from 20 to 3 μm, using sedimentation times of 6 and 2 h respectively. Such filtered microparticles also have much narrower size distributions and are hence suitable for administration in 27 gauge microneedles, commonly used in intravitreal drug delivery.

Realised added value in dynamical downscaling of Australian climate change

2021 ◽  
Author(s):  
Giovanni Di Virgilio ◽  
Jason P. Evans ◽  
Alejandro Di Luca ◽  
Michael R. Grose ◽  
Vanessa Round ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Climate Adaptation ◽  
Regional Climate ◽  
Future Climate ◽  
Added Value ◽  
Climate Projections ◽  
Eastern Australia ◽  
Australian Alps ◽  
Future Climate Projections

<p>Coarse resolution global climate models (GCM) cannot resolve fine-scale drivers of regional climate, which is the scale where climate adaptation decisions are made. Regional climate models (RCMs) generate high-resolution projections by dynamically downscaling GCM outputs. However, evidence of where and when downscaling provides new information about both the current climate (added value, AV) and projected climate change signals, relative to driving data, is lacking. Seasons and locations where CORDEX-Australasia ERA-Interim and GCM-driven RCMs show AV for mean and extreme precipitation and temperature are identified. A new concept is introduced, ‘realised added value’, that identifies where and when RCMs simultaneously add value in the present climate and project a different climate change signal, thus suggesting plausible improvements in future climate projections by RCMs. ERA-Interim-driven RCMs add value to the simulation of summer-time mean precipitation, especially over northern and eastern Australia. GCM-driven RCMs show AV for precipitation over complex orography in south-eastern Australia during winter and widespread AV for mean and extreme minimum temperature during both seasons, especially over coastal and high-altitude areas. RCM projections of decreased winter rainfall over the Australian Alps and decreased summer rainfall over northern Australia are collocated with notable realised added value. Realised added value averaged across models, variables, seasons and statistics is evident across the majority of Australia and shows where plausible improvements in future climate projections are conferred by RCMs. This assessment of varying RCM capabilities to provide realised added value to GCM projections can be applied globally to inform climate adaptation and model development.</p>

scholarly journals Centennial-scale variability of the Southern Hemisphere westerly wind belt in the eastern Pacific over the past two millennia

2014 ◽  
Vol 10 (3) ◽  
pp. 1125-1144 ◽  
Author(s):  
B. G. Koffman ◽  
K. J. Kreutz ◽  
D. J. Breton ◽  
E. J. Kane ◽  
D. A. Winski ◽  
...  
Keyword(s):  
Particle Size ◽  
Wind Speed ◽  
Atmospheric Circulation ◽  
Southern Hemisphere ◽  
Zonal Wind ◽  
Ice Core ◽  
Eastern Pacific ◽  
The Past ◽  
West Antarctic ◽  
Lower Elevation

Abstract. We present the first high-resolution (sub-annual) dust particle data set from West Antarctica, developed from the West Antarctic Ice Sheet (WAIS) Divide deep ice core (79.468° S, 112.086° W), and use it to reconstruct changes in atmospheric circulation over the past 2400 years. We find a background dust flux of ~4 mg m−2 year−1 and a mode particle size of 5–8 μm diameter. Through comparing the WAIS Divide record with other Antarctic ice core particle records, we observe that coastal and lower-elevation sites have higher dust fluxes and coarser particle size distributions (PSDs) than sites on the East Antarctic plateau, suggesting input from local dust sources at these lower-elevation sites. In order to explore the use of the WAIS Divide dust PSD as a proxy for past atmospheric circulation, we make quantitative comparisons between both mid-latitude zonal wind speed and West Antarctic meridional wind speed and the dust size record, finding significant positive interannual relationships. We find that the dust PSD is related to mid-latitude zonal wind speed via cyclonic activity in the Amundsen Sea region. Using our PSD record, and through comparison with spatially distributed climate reconstructions from the Southern Hemisphere (SH) middle and high latitudes, we infer that the SH westerlies occupied a more southerly position from circa 1050 to 1400 CE (Common Era), coinciding with the Medieval Climate Anomaly (MCA). Subsequently, at ca. 1430 CE, the wind belt shifted equatorward, where it remained until the mid-to-late twentieth century. We find covariability between reconstructions of El Niño–Southern Oscillation (ENSO) and the mid-latitude westerly winds in the eastern Pacific, suggesting that centennial-scale circulation changes in this region are strongly influenced by the tropical Pacific. Further, we observe increased coarse particle deposition over the past 50 years, consistent with observations that the SH westerlies have been shifting southward and intensifying in recent decades.

scholarly journals Uranium-series isotopes from Eemian lake deposits, Hollerup, Denmark

1998 ◽  
Vol 44 ◽  
pp. 173-179
Author(s):  
C. Israelson ◽  
S. Bjorck ◽  
N. Noe Nygaard ◽  
C. J. Hawkesworth
Keyword(s):  
Ground Water ◽  
Lake Sediments ◽  
Sedimentary Facies ◽  
Organic Content ◽  
Time Interval ◽  
Decay Products ◽  
Large Spread ◽  
Isotope Study ◽  
Lake Deposits ◽  
High Organic Content

We report the results of a U-series isotope study on Eemian lake sediments from Hollerup, western Denmark. The purpose is to examine the possibility of dating these, and similar, sediments with the 238U-23"h method. Two sedimentary facies were studied; carbonate-present, and virtually carbonate-free but organic-rich sediments. All carbonate-present sediments (5-95%) have (230ThP38U) values higher than unity and relatively radiogenic (23"W232Th) values between 2 and 6.5, indicating postdeposition removal of U, probably by percolation of ground water. Carbonate-free sediments, but with high organic content (40-60%) had (230Th/238U) values lower than 1 and 'model ages' between 89 and 199 ky. The large spread in ages and variation in U content for these sediment samples that were deposited over a much shorter time interval, indicate a complex postdepositional migration pattern of U, probably involving several episodes of leaching and absorption of U from ground water. Our results suggest that lake sediments, such as those found in Hollerup, are vulnerable to mobilization of U and its decay products and care should be taken when interpreting U-series disequilibrium data from such sediments. Future studies will concentrate on sediments that have been more deeply buried andor are less compacted and sealed from percolation of oxidized groundwater.

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