scholarly journals Clay-organic complexes in a Polish loess soil

2017 ◽  
Vol 31 (3) ◽  
pp. 447-452 ◽  
Author(s):  
Ewa A. Czyż ◽  
Jerzy Rejman ◽  
Anthony R. Dexter ◽  
Jan Jadczyszyn ◽  
Anna Rafalska-Przysucha ◽  
...  
Keyword(s):  
Loess Soil ◽  
Soil Samples ◽  
Mass Ratio ◽  
Loessial Soil ◽  
Soil Physical Quality ◽  
Organic Complexes ◽  
Carbon Mass ◽  
Predicted Values ◽  
Strip Tillage ◽  
Range Of Values

AbstractComplexes formed between clay and soil organic matter are important for carbon sequestration and for soil physical quality. Here, we use samples of loessial soil from South-East Poland to explore the phenomenon of complexing in loess. Soil samples were collected from a single catchment 8 years after the introduction of strip tillage and their compositions were characterized by traditional methods. Complexing was characterized in terms of the content of non-complexed clay which was estimated in two ways: firstly, by measurement of the content of readily-dispersible clay (which was assumed to be the non-complexed clay); and secondly, by calculation using algorithms that had been developed and evaluated previously. The calculations were based on the concept that, at carbon saturation, the clay/organic carbon mass ratio is equal ton. The calculations were done with a range of values ofn. It was assumed that the correct value ofnwas that which gave the greatest coefficient of correlation between the measured values of clay dispersion and the predicted values of non-complexed clay. For the loess used, the optimum value wasn= 14.

scholarly journals Heavy metal tolerance of Pontechium maculatum (Boraginaceae) from several ultramafic localities in Serbia

2019 ◽  
Vol 43 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Ksenija Jakovljevic ◽  
Sanja Djurovic ◽  
Mina Antusevic ◽  
Nevena Mihailovic ◽  
Uros Buzurovic ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Heavy Metal Stress ◽  
Balkan Peninsula ◽  
Major And Trace Elements ◽  
Soil Samples ◽  
Plant Tissues ◽  
Trace Element Profiles ◽  
Range Of Values

Pontechium maculatum, a facultative metallophyte, was collected from four ultramafic localities in Serbia and analysed in terms of micro- and macroelement accumulation. The aim of the study was to reveal trace element profiles and differences in uptake and translocation of heavy metals in populations growing under heavy metal stress. The concentrations of major and trace elements in soil samples (Ca, Mg, Fe, Mn, Ni, Pb, Cr, Zn, Cu, Co, Cd) and in plant tissues (Fe, Mn, Ni, Pb, Cr, Zn, Cu, Co, Cd) are presented. The results of our analysis indicate that P. maculatum efficiently absorbs Zn and Cr, while for most of the other elements accumulation levels fit in the range of values obtained for several other species from ultramafic localities on the Balkan Peninsula.

scholarly journals A new technique for firn grain-size measurement using SEM image analysis

2010 ◽  
Vol 56 (195) ◽  
pp. 12-19 ◽  
Author(s):  
N.E. Spaulding ◽  
D.A. Meese ◽  
I. Baker ◽  
P.A. Mayewski ◽  
G.S. Hamilton
Keyword(s):  
Grain Size ◽  
Boundary Diffusion ◽  
Ice Core ◽  
New Technique ◽  
Sem Image ◽  
Grain Sizes ◽  
A New Technique ◽  
Predicted Values ◽  
Range Of Values ◽  
Sem Image Analysis

AbstractFirn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Gow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the grain area) in earlier methods. The new technique offers the advantages of greater accuracy and the ability to determine individual components of the microstructure (grain and pore), which have important applications in ice-core analyses. The new method is validated by calculating activation energies of grain boundary diffusion using predicted values based on the ratio of grain-size measurements between the new and existing techniques. The resulting activation energy falls within the range of values previously reported for firn/ice.

scholarly journals Estimation of radioecological parameters of soil samples from a phosphatic area

2016 ◽  
Vol 31 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Shaaban Harb ◽  
Noor Ahmed ◽  
Wael Badawy ◽  
Nagwa Saad
Keyword(s):  
Dose Rate ◽  
Annual Effective Dose ◽  
Natural Radionuclides ◽  
Significant Risk ◽  
Absorbed Dose ◽  
Soil Samples ◽  
Absorbed Dose Rate ◽  
Activity Concentrations ◽  
Average Activity ◽  
Range Of Values

The activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) for a set of 31 agricultural soil samples from the Nile River banks in the area of El-Sebaiya city, Aswan Governorate, Egypt were measured by gamma-spectrometry. The study revealed that the average activity concentrations of natural radionuclides 226Ra, 232Th, and 40K were 23.2 ? 2.8Bq/kg, 21.1 ? 2.8 Bq/kg, and 218.6 ? 3.7 Bq/kg, respectively. The obtained results of the activity concentrations are within the range of values reported for neighbouring areas in Egypt. The values obtained for the hazard indices and the representative level index in all sampling sites were lower than unity, showing that there is no significant risk arising from the exposure to the soil in the studied area. The absorbed dose rate and annual effective dose in air outdoors and indoors were calculated from 226Ra, 232Th, and 40K in soil, the average values being 32.64 nGy/h, 40.06 ?Sv, and 160.25 ?Sv, respectively. The absorbed dose rate at the eastof El-Sebaiya city is higher than that obtained for the west because of higher concentrations of tri-calcium phosphate in the soil. The studied area is not significantly affected by the industrial activities, except for a few isolated spots.

Research on Micro-Electrolysis Method to Treat the Copper-Containing Electroplating Wastewater

2013 ◽  
Vol 864-867 ◽  
pp. 1560-1563
Author(s):  
Yi Ting Zhang ◽  
Hai Bo Lun
Keyword(s):  
Wastewater Treatment ◽  
Reaction Time ◽  
Total Mass ◽  
Removal Rate ◽  
Mass Ratio ◽  
Experimental Conditions ◽  
Electroplating Wastewater ◽  
Initial Ph ◽  
Carbon Mass ◽  
Electrolysis Method

Iron-carbon micro-electrolysis was applied in the treatment of the electroplating wastewater containing copper, and the parameters that affected the efficiencies of the wastewater treatment had been discussed, The results indicated that the optimal experimental conditions were initial pH 4, stirring speed 100r/min, total mass of iron and carbon 4g/0.1L, iron carbon mass ratio of 1, reaction time was 40min. The removal rate of the Cu2+was 99% or more, the effluent can meet emissions standards

scholarly journals On the Prediction of Strength from Hardness for Copper Alloys

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. Chenna Krishna ◽  
Narendra Kumar Gangwar ◽  
Abhay K. Jha ◽  
Bhanu Pant
Keyword(s):  
Strain Hardening ◽  
Entire Range ◽  
Copper Alloys ◽  
Least Squares Regression ◽  
Dispersion Strengthening ◽  
Solid Solution Strengthening ◽  
Bulk Hardness ◽  
Predicted Values ◽  
Experimental Values ◽  
Range Of Values

Hardness and strength values of over 55 copper alloys strengthened by solid solution strengthening, precipitation hardening, cold working, and dispersion strengthening were compiled. The yield strength (YS) and ultimate tensile strength (UTS) values of the copper alloys examined ranged between 50 to 1300 MPa and 200 to 1400 MPa, respectively. The compiled values were classified based on strain-hardening potential an indirect method to understand the effect of strain-hardening characteristics. Least squares regression analysis was employed to establish correlations between strength and Vickers hardness values. Strain-hardening potential showed a significant effect on the correlations. In all the cases, a linear relation was obtained for both YS and UTS with hardness for the entire range of values under analysis. Simple empirical equations were proposed to estimate the strength using bulk hardness. The proposed correlations obtained for the entire range of values were verified with experimental values. A good agreement was observed between experimental and predicted values.

scholarly journals Fabrication of titanium carbide reinforced iron matrix cermet by vacuum carbothermal reduction of ilmenite

2019 ◽  
Vol 25 (1) ◽  
pp. 21-29
Author(s):  
Ke-Han Wu ◽  
Hai-Peng Gou ◽  
Guo-Hua Zhang ◽  
Kuo-Chih Chou
Keyword(s):  
Carbothermal Reduction ◽  
Bending Strength ◽  
Raw Materials ◽  
Energy Dispersive Spectrometer ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Iron Matrix ◽  
Vacuum Sintering ◽  
Electron Probe Micro Analyzer ◽  
Carbon Mass

Iron matrix cermet reinforced with TiC has been produced by vacuum carbothermal reduction of ilmenite followed by sintering processes. The influences of reduction temperature and carbon mass ratio were discussed in detail. X-Ray diffraction (XRD), electron probe micro-analyzer (EPMA) and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) were employed to characterize the phase composition and microstructures. After carbothermic reduction, most of Mg, Mn, Ca evaporated from the sample; Si and part of Al was dissolved in the iron matrix. The obtained powders were used as the raw materials to produce TiC-Fe cermet by vacuum sintering. Density, hardness and bending strength of the samples were examined. The optimal cermet products after heat treatment had a density of 5.38 g?cm-1, a hardness of 1125.5 HV and a bending strength of 667 MPa, which was obtained at the carbon/ilmenite mass ratio of 0.378:1 at 1773 K under the pressure of 10 Pa.

scholarly journals Synthesis and characterization of Architecturally Modified Mesoporous-microporous MFI (Mobil Five) Zeolite with enhanced catalytic activity

2021 ◽  
Author(s):  
Dhanju Mani Pathak ◽  
Pankaj Kumar Ghosh ◽  
Kishor Kr Shah ◽  
Anup K Talukdar
Keyword(s):  
Carbon Black ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Silica Alumina ◽  
Carbon Mass ◽  
Mfi Zeolites ◽  
Adsorption Desorption

Abstract Four samples MFI zeolites were synthesized in presence of carbon black particles with silica-alumina molar ratio of 100 and different silica to carbon mass ratio under autogeneous pressure without adding any promoter or organic solvent. The synthesis temperature and duration of crystallization were 473K and 16h respectively. A sample of MFI was also synthesized without adding carbon black under similar condition. The synthesized samples were characterized by different techniques such as X- ray diffraction, FT-IR spectroscopy, Scanning electron microscopy, TGA and N2 adsorption desorption. The samples exhibit high crystallinity. The particle size ranged from 2.8 to 7.3 µm. Mesopore to micropore ratios was found to increase with increasing silicon to carbon mass ratio. These structurally modified meso-micro zeolite showed enhanced activity in the benzyl alcohol esterification reaction.

Pretreatment of Pharmaceutical Wastewater by Microelectrolysis of Iron and Fenton Reagent

2015 ◽  
Vol 1092-1093 ◽  
pp. 1051-1055
Author(s):  
Jun Hua Fang ◽  
Min Huang ◽  
Li Qing Ren
Keyword(s):  
Reaction Time ◽  
Optimal Operation ◽  
Raw Water ◽  
Optimal Parameters ◽  
Mass Ratio ◽  
Fenton Reagent ◽  
Pharmaceutical Wastewater ◽  
Operation Conditions ◽  
Water Ph ◽  
Carbon Mass

The characteristics of raw pharmaceutical wastewater was as follows: CODCr30000~32000 mg/L, BOD54050~4360 mg/L, B/C: 0.12~0.14, Fe-C micro-electrolysis with Fenton reagent was adopted to pretreat this wastewater. Through static experiments analysis, optimal parameters of iron-carbon microelectrolysis Fenton pretreatment process are listed as follows: raw water pH, iron-carbon mass ratio (i.e. 2:3), the mass of iron-carbon (i.e. 500 g/L) and reaction time (i.e. 2 h). The optimal operation conditions (i.e. H2O2dosage is12 mg/L, pH is 3.5, reaction time is 80 min) of Fenton reagent oxidation were confirmed.

The effect of soil type and crust cover on the absorption of atmospheric water vapor – laboratory and field trials.

2020 ◽  
Author(s):  
Pedro Berliner ◽  
Anxia Jiang ◽  
Carmel Neuberger ◽  
Agam Nurit
Keyword(s):  
Water Vapor ◽  
Field Experiment ◽  
Open Field ◽  
Soil Type ◽  
Loess Soil ◽  
Soil Samples ◽  
Atmospheric Water Vapor ◽  
Sand Sample ◽  
Atmospheric Water ◽  
Biological Origin

<p>In arid and semiarid environments non-rainfall water inputs (NRWI) are an important source of water. In Israel's Negev desert direct absorption of atmospheric water vapor is the dominant NRWI and is strongly affected by soil properties, in particular clay content. The presence of a surface crust layer, whose physical and physico-chemical properties are substantially different from those of the underlying undisturbed substrate will likely affect the absorption patterns.  The objective of our study was to quantify the effect of soil type (loess vs. sand) and crust cover (crust vs. crust removed) on direct atmospheric water absorption.</p><p>The loess soil samples were obtained in an open field adjacent to the Jacob Bluestein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev (30˚51’ N, 034˚46’ E, 470 m a.s.l); and the sand samples from the Nizzana Sand Dune area (30˚58’N, 034˚24’E, 226 m a.s.l.).  The loess crusts were physically induced while those present on the sand samples were of biological origin.</p><p>A field experiment was carried out in the open field adjacent to the BIDR.  Four undisturbed 0.5 m depth soil samples (sand and loess with crust and with crust removed) were placed in micro-lysimeters and automatically weighed at 30 min. intervals.  This field experiment was carried during the dry season of May to October 2016.</p><p>The field study was supplemented with a laboratory experiment in which undisturbed samples (1,3, 7 and 10 cm) obtained from the above mentioned sites were used. Oven-dry samples were exposed during 6 days to constant temperature and relative humidity conditions (25±1 <sup>o</sup>C and  85±5 %, respectively)  in sealed chambers.  Mass changes were recorded at varying time intervals.   </p><p>The adsorption process in the field started in the late afternoon with the arrival of the sea breeze and ended with sun rise. On a daily basis the crusted loess sample adsorbed more water than the crusted sand sample, and the crust removed loess soil absorbed more water than the crust removed sand.  The crusted samples generally absorbed less water than the corresponding non-crusted ones.</p><p>The results of the laboratory tests showed that loess samples with crust and with crust removed absorbed similar water amounts for all sample depths throughout the study period. The crusted sand samples however absorbed systematically more water than the crust removed samples for all sample depths.</p><p>We conclude that the higher resistance of crusts to gaseous flux, a result of their higher bulk density and smaller pores, does not limit water vapor flux into the deeper soil layers and does not explain the field results.  </p>

scholarly journals Extraction of Humic Acid from Lignite by KOH-Hydrothermal Method

2019 ◽  
Vol 9 (7) ◽  
pp. 1356 ◽  
Author(s):  
Gan Cheng ◽  
Zeyu Niu ◽  
Chuanxiang Zhang ◽  
Xiaoming Zhang ◽  
Xusheng Li
Keyword(s):  
Humic Acid ◽  
Hydrothermal Method ◽  
Reaction Temperature ◽  
Size Fraction ◽  
Physicochemical Characterization ◽  
Proximate Analysis ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Carbon Mass ◽  
Residual Coal

Humic acid (HA) was extracted by a hydrothermal method from Huolinhe lignite from Inner Mongolia. The effects of the alkali-to-carbon mass ratio, water-to-coal mass ratio, reaction temperature, and reaction time on the HA yield were investigated. The physicochemical characterization of the products was performed, and the reaction mechanism was explored. Raw coal, HA, and residual coal were characterized using Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–VIS), elemental composition, and X-ray diffraction (XRD) analyses and compared to each other. The maximum HA yield (90.2%) was obtained from the 0.250–0.180 mm size fraction of the coal sample at a reaction temperature and time of 190 °C and 7 h. Proximate analysis proved that the ash and sulfur of lignite can be removed by hydrothermal treatment. Elemental analysis showed that the O/C and H/C ratios were highest for HA, followed by those for residual coal and raw coal, indicating an increase in the oxygen and hydrogen content of HA. FTIR and UV–VIS analyses showed that hydrothermal extraction destroyed the macromolecular structure of lignite. Moreover, the organics were degraded and hydrolyzed during the reaction process.

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