INFLUENCE OF ORGANIC MATTER AND IRON OXIDES ON THE COLOUR PROPERTIES OF A MICRITIC LIMESTONE FROM KEFALONIA

The influence of organic matter and iron oxides on the colour properties of an ultra-high purity micritic limestone from Kefalonia Island containing 99.7% calcite was studied. Colouring impurities, organic matter and iron-oxide, were added in the form of a xylitic lignite and a hematite-rich Fe-ore respectively. Both impurities decrease lightness (L*) and increase deviation from perfect white diffuser (AE*ab) as well as redness and yellowness of calcite. Organic matter affects colour properties to a greater degree than iron oxides. The results obtained were used in a model, which predicts lightness and AE*ab of white limestones and marbles from their Fe2Ü3 and organic carbon content. The theoretical values of L* and AE*ab of a series of known limestones and calcific marbles obtained from this model are comparable to experimental values determined using a colourimeter. Slight deviations between theoretical and experimental values are attributed to several factors, which include the different nature of iron oxides/oxyhydroxides (goethite or/and lepidocrocite and/or amorphous Fe-oxyhydroxides instead of hematite) and organic matter (kerogene instead of xylitic lignite) present in the carbonate rocks, the different particle size of calcite and impurities in the different carbonates, to the multiphase nature of the colouring impurities used in this study and to the possible existence of other Fe-rich phases such as Fe-carbonates in the limestones. The proposed model can facilitate quality control of limestone resources used as fillers and can be extended to dolomitic rocks.

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Impact of soil use on aggregate stability and its relationship with soil organic carbon at two different altitudes in the Colombian Andes

Agronomía Colombiana ◽

10.15446/agron.colomb.v37n3.77601 ◽

2019 ◽

Vol 37 (3) ◽

pp. 263-273

Author(s):

Efraín Francisco Visconti-Moreno ◽

Ibonne Geaneth Valenzuela-Balcázar

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Aggregate Stability ◽

Tropical Climate ◽

Mineral Particle ◽

Organic Carbon Content ◽

Rice Soils ◽

Organic Matter Pool ◽

Different Altitudes

The stability of soil aggregates depends on the organic matter, and the soil use and management can affect the soil organicmatter (SOM) content. Therefore, it is necessary to know therelationship between aggregate stability and the content of SOMin different types of soil use at two different altitudes of theColombian Andes. This study examined the conditions of soilaggregate stability expressed as a distribution of the size classes of stable aggregates (SA) and of the mean weighted diameter of the stable aggregates (MWD). To correlate these characteristics with the soil organic carbon (OC), we measured the particulate organic matter pool (POC), the OC associated with the mineral organic matter pool (HOC), the total organic carbon content (TOC), and the humification rate (HR). Soils were sampled at two altitudes: 1) Humic Dystrudepts in a cold tropical climate (CC) with three plots: tropical mountain rainforest, pastures, and crops; 2) Fluvaquentic Dystrudepts in a warm tropical climate (WC) with three plots: tropical rainforest, an association of oil palm and pastures, and irrigated rice. Soils were sampled at three depths: 0-5, 5-10 and 10-20 cm. The physical properties, mineral particle size distribution, and bulk density were measured. The content of SA with size>2.36 mm was higher in the CC soil (51.48%) than in the WC soil (9.23%). The SA with size 1.18-2.36 mm was also higher in the CC soil (7.78%) than in the WC soil (0.62%). The SA with size 0.60-1.18 mm resulted indifferent. The SA with size between 0.30 and 0.60 mm were higher in the WC soil (13.95%) than in the CC soil (4.67%). The SA<0.30 mm was higher in the WC soil (72.56%) than in the CC soil (32.15%). It was observed that MWD and the SA>2.36 mm increased linearly with a higher POC, but decreased linearly with a higher HR. For the SA<0.30 mm, a linear decrease was observed at a higher POC, while it increased at a higher HR.

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Experimental and Numerical Analysis of the Nickel Deposition and Diffusion Using Plasma in a Confined Anode-Cathode Configuration

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.283-286.183 ◽

2009 ◽

Vol 283-286 ◽

pp. 183-189 ◽

Cited By ~ 1

Author(s):

Rodrigo Perito Cardoso ◽

A.M. Maliska ◽

C.R. Maliska

Keyword(s):

Deposition Process ◽

Interstitial Free ◽

Cathode Voltage ◽

Nickel Deposition ◽

Plasma Sintering ◽

Pulsed Dc ◽

Proposed Model ◽

Constant Rate ◽

Experimental Values ◽

Volume Method

This work presents a theoretical and experimental study of nickel deposition on iron samples at relatively high pressure using a pulsed DC glow discharge. The deposition process was conducted in conditions similar to that used for plasma sintering, using the confined anode-cathode configuration. The cathode was made from nickel commercially pure and the samples were made from interstitial free steel and sintered pure iron. The samples were characterized by mass weight gain, scanning electron microscopy and energy-dispersive X-ray microanalysis. The deposition process was mathematically modeled and the model was numerically solved using a conservative finite-volume method. The experiments demonstrated that the deposition occurs at a constant rate, with the mass flux changing linearly with the cathode voltage in the range of parameters considered. The results obtained from the diffusion model applied to the sample presented good agreement with the experimental values. Concerning the gas phase, the proposed model helped us to clarify some phenomenological aspects of the process. However, further studies, principally in the area of electrical discharges, are needed to permit a complete comprehension of this process.

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Ignition and flame quenching of quiescent fuel mists

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1978.0201 ◽

1978 ◽

Vol 364 (1717) ◽

pp. 277-294 ◽

Cited By ~ 41

Keyword(s):

Reaction Rates ◽

Ignition Energy ◽

Minimum Ignition Energy ◽

Proposed Model ◽

Theoretical Predictions ◽

Quenching Distance ◽

Experimental Values ◽

Sole Criterion ◽

Fuel Vapour ◽

Level Of Agreement

A model is proposed for the ignition of quiescent multidroplet fuel mists which assumes that chemical reaction rates are infinitely fast, and that the sole criterion for successful ignition is the generation, by the spark, of an adequate concentration of fuel vapour in the ignition zone. From analysis of the relevant heat transfer and evaporation processes involved, expressions are derived for the prediction of quenching distance and minimum ignition energy. Support for the model is demonstrated by a close level of agreement between theoretical predictions of minimum ignition energy and the corresponding experimental values obtained using a specially designed ignition apparatus in which ignition energies are measured for several different fuels, over wide ranges of pressure, mixture composition and mean drop size. The results show that both quenching distance and minimum ignition energy are strongly dependent on droplet size, and are also dependent, but to a lesser extent, on air density, equivalence ratio and fuel volatility. An expression is derived to indicate the range of drop sizes over which the proposed model is valid.

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CLAY ILLUVIATION IN SOME ORTHIC PODZOLS OF EASTERN CANADA

Canadian Journal of Soil Science ◽

10.4141/cjss65-020 ◽

1965 ◽

Vol 45 (2) ◽

pp. 127-138 ◽

Cited By ~ 7

Author(s):

J. E. Brydon

Keyword(s):

Organic Matter ◽

New Brunswick ◽

Iron Oxides ◽

Clay Content ◽

Granular Structure ◽

Charge Component ◽

Eastern Canada ◽

Free Iron ◽

Fine Clay ◽

Ph Dependent

The Arago, Barney, and Holmesville soils, Podzols from Quebec, Nova Scotia, and New Brunswick, respectively, each had friable Bfh horizons with moderate granular structure, and with organic matter and free Fe2O3 contents greater than the Ae and C horizons. The Arago and Holmesville had thin Bhft horizons containing over 10% organic matter and 5% free iron oxides. The C horizons of these two soils had some features characteristic of fragipans.The B horizons of the three soils had a high "pH-dependent charge component" in the C.E.C. values. The "permanent charge component" was similar throughout the Arago profile except for the Bhft horizon where clay accumulation had occurred.Translocation of clay from the Ae to the upper B horizons was indicated by the twofold increase in clay content and the relative enrichment of fine clay in the B horizons. Removal of free iron affected the clay contents differently in the different: horizons but the maximum clay content in the upper B horizons remained. The definitions of Orthic Podzols, Textural Podzols, and t horizons should be re-examined.

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Numerical Simulation of Water Absorption and Swelling in Dehulled Barley Grains during Canned Porridge Cooking

Processes ◽

10.3390/pr6110230 ◽

2018 ◽

Vol 6 (11) ◽

pp. 230 ◽

Cited By ~ 2

Author(s):

Lei Wang ◽

Mengting Wang ◽

Mingming Guo ◽

Xingqian Ye ◽

Tian Ding ◽

...

Keyword(s):

Moisture Absorption ◽

Three Dimensional ◽

Processing Conditions ◽

Relative Deviation ◽

Cooking Process ◽

Proposed Model ◽

Hygroscopic Swelling ◽

3D Numerical Model ◽

Barley Grains ◽

Experimental Values

Understanding the hydration behavior of cereals during cooking is industrially important in order to optimize processing conditions. In this study, barley porridge was cooked in a sealed tin can at 100, 115, and 121 °C, respectively, and changes in water uptake and hygroscopic swelling in dehulled barley grains were measured during the cooking of canned porridge. In order to describe and better understand the hydration behaviors of barley grains during the cooking process, a three-dimensional (3D) numerical model was developed and validated. The proposed model was found to be adequate for representing the moisture absorption characteristics with a mean relative deviation modulus (P) ranging from 4.325% to 5.058%. The analysis of the 3D simulation of hygroscopic swelling was satisfactory for describing the expansion in the geometry of barley. Given that the model represented the experimental values adequately, it can be applied to the simulation and design of cooking processes of cereals grains, allowing for saving in both time and costs.

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Determination of Recrystallization Kinetics Model of 30Cr2Ni4MoV Steel Based on Dislocation Density

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.263.59 ◽

2017 ◽

Vol 263 ◽

pp. 59-66

Author(s):

Peng Zhou ◽

Qing Xian Ma

Keyword(s):

Dislocation Density ◽

Model Comparison ◽

Kinetics Model ◽

Structure Evolution ◽

Metallographic Analysis ◽

Recrystallization Kinetics ◽

Proposed Model ◽

Different Temperatures ◽

Predicted Values ◽

Experimental Values

A new model to predict the structure evolution of 30Cr2Ni4MoV steel is proposed based on the dislocation density in this research. Hot compression of 30Cr2Ni4MoV steel is carried out on Gleeble 1500 at different temperatures from 1233 K to 1473 K with a strain rate of 0.01 s-1 and the deformed samples are immediately quenched by water to frozen the austenite structure. The recrystallization kinetics model of 30Cr2Ni4MoV steel is successfully established by inverse analysis of the flow curve based on the relation between flow stress and dislocation density. In order to validate the proposed model, comparison between the predicted values and experimental values obtained by metallographic analysis is implemented. It is shown that the predicted results agree with the experimental results well.

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Short-Term Decomposition and Nutrient-Supplying Ability of Sewage Sludge Digestate, Digestate Compost, and Vermicompost on Acidic Sandy and Calcareous Loamy Soils

Agronomy ◽

10.3390/agronomy11112249 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2249

Author(s):

Nikolett Uzinger ◽

Orsolya Szécsy ◽

Nóra Szűcs-Vásárhelyi ◽

István Padra ◽

Dániel Benjámin Sándor ◽

...

Keyword(s):

Organic Matter ◽

Sewage Sludge ◽

Organic Carbon ◽

Carbon Content ◽

Plant Biomass ◽

Test Plant ◽

Organic Carbon Content ◽

Short Term ◽

Mineral N ◽

Average Residual

Organic waste and the compost and vermicompost derived from it may have different agronomic values, but little work is available on this aspect of sewage sludge. A 75-day pot experiment with perennial ryegrass (Lolium perenne) as the test plant aimed to investigate the fertiliser value and organic matter replenishment capacity of digested sewage sludge (DS) and the compost (COM) and vermicompost (VC) made from it, applied in 1% and 3% doses on acidic sand and calcareous loam. The NPK content and availability, changes in organic carbon content and plant biomass, and the efficiency of the amendments as nitrogen fertilisers were investigated. The final average residual carbon content for DS, COM, and VC was 35 ± 34, 85 ± 46, and 55 ± 46%, respectively. The organic carbon mineralisation rate depended on the soil type. The additives induced significant N mineralisation in both soils: the average increment in mineral N content was 1.7 times the total added N on acidic sand and 4.2 times it on calcareous loam for the 1% dose. The agronomic efficiency of COM and VC as fertilisers was lower than that of DS. In the short term, DS proved to be the best fertiliser, while COM was the best for organic matter replenishment.

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Effect of Tillage System and Organic Matter Management Interactions on Soil Chemical Properties and Biological Activity in a Spring Wheat Short-Time Cultivation

Energies ◽

10.3390/en14217451 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7451

Author(s):

Barbara Breza-Boruta ◽

Karol Kotwica ◽

Justyna Bauza-Kaszewska

Keyword(s):

Organic Matter ◽

Biological Activity ◽

Organic Carbon ◽

Spring Wheat ◽

Chemical Properties ◽

Soil Samples ◽

Available Phosphorus ◽

Organic Carbon Content ◽

Tillage System ◽

Short Time

Properly selected tillage methods and management of the available organic matter resources are considered important measures to enable farming in accordance with the principles of sustainable agriculture. Depending on the depth and intensity of cultivation, tillage practices affect soil chemical composition, structure and biological activity. The three-year experiment was performed on the soil under spring wheat (cv. Tybalt) short-time cultivation. The influence of different tillage systems and stubble management on the soil’s chemical and biological parameters was analyzed. Organic carbon content (OC); content of biologically available phosphorus (Pa), potassium (Ka), and magnesium (Mg); content of total nitrogen (TN), mineral nitrogen forms: N-NO3 and N-NH4 were determined in various soil samples. Moreover, the total number of microorganisms (TNM), bacteria (B), actinobacteria (A), fungi (F); soil respiratory activity (SR); and pH in 1 M KCl (pH) were also investigated. The results show that organic matter amendment is of greater influence on soil characteristics than the tillage system applied. Manure application, as well as leaving the straw in the field, resulted in higher amounts of organic carbon and biologically available potassium. A significant increase in the number of soil microorganisms was also observed in soil samples from the experimental plots including this procedure.

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Modeling biogeochemical processes in sediments from the Rhône River prodelta area (NW Mediterranean Sea)

Biogeosciences Discussions ◽

10.5194/bgd-8-549-2011 ◽

2011 ◽

Vol 8 (1) ◽

pp. 549-592 ◽

Cited By ~ 2

Author(s):

L. Pastor ◽

C. Cathalot ◽

B. Deflandre ◽

E. Viollier ◽

K. Soetaert ◽

...

Keyword(s):

Organic Matter ◽

Oxygen Consumption ◽

Continental Shelf ◽

Carbon Mineralization ◽

River Mouth ◽

Total Carbon ◽

Large Contribution ◽

Organic Carbon Content ◽

Rhône River ◽

Rhone River

Abstract. In-situ oxygen microprofiles, sediment organic carbon content and pore-water concentrations of nitrate, ammonium, iron, manganese and sulfides obtained in sediments from the Rhône River prodelta and its adjacent continental shelf were used to constrain a numerical diagenetic model. Results showed that (1) organic matter from the Rhône River is composed of a fraction of fresh material associated to high first-order degradation rate constants (11–33 yr−1), (2) burial efficiency (burial/input ratio) in the Rhône prodelta (within 3 km of the river outlet) can be up to 80%, and decreases to ~20% on the adjacent continental shelf 10–15 km further offshore (3) there is a large contribution of anoxic processes to total mineralization in sediments near the river mouth, certainly due to large inputs of fresh organic material combined with high sedimentation rates, (4) diagenetic by-products originally produced during anoxic organic matter mineralization are almost entirely precipitated (>97%) and buried in the sediment, which leads to (5) a low contribution of the re-oxidation of reduced products to total oxygen consumption. Consequently, total carbon mineralization rates as based on oxygen consumption rates and using Redfield stoichiometry can be largely underestimated in such River Ocean dominated Margins (RiOMar) environments.

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SEDIMENTOLOGICAL AND GEOCHEMICAL ANALYSIS OF MIOCENE DEPOSITS IN MOSCHOPOTAMOS AREA, IN THE WESTERN PART OF AXIOS-THERMAIKOS BASIN, NW GREECE

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11738 ◽

2017 ◽

Vol 50 (1) ◽

pp. 374

Author(s):

V. Savva ◽

P. Tserolas ◽

A. Maravelis ◽

N. Bourli ◽

A. Zelilidis

Keyword(s):

Organic Matter ◽

Organic Content ◽

Sieve Analysis ◽

Organic Carbon Content ◽

Geochemical Analysis ◽

Aegean Area ◽

Sedimentary Characteristics ◽

The North ◽

Caco3 Content ◽

North Aegean

A total of 27 samples of the Moschopotamos area lignite-bearing strata were studied in regard of their geochemical and sedimentary characteristics. Organic content and calcium carbonate evaluation, sieve analysis and micropaleontological observations were used and combined to investigate the paleoenvironment and the depositional conditions of the study area. TOC analysis showed that organic matter values range from 0.07% up to 13.42% with an average of ~3.26 %. The high average of organic carbon content indicates a promising basis for the sediments’ source rock potential, inquiring further and thorough examination. CaCO3 measurements present a range between 4% and 23%. A comparison between TOC-CaCO3 content throughout the stratigraphic column presented certain synchronous and inverse trends, due to alterations of the depositional conditions. This study provides new insights for the understanding of the broader Axios-Thermaikos basin, and depositional conditions in the North Aegean area.

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