Effects of (Li-Na)2CO3 on The Electrical Properties of Calcia-Stabilized Zirconia/Carbonate Composite Electrolytes

Calcia-Stabilized Zirconia (CSZ) is potential as low-cost electrolytes material for Solid oxide fuel cell (SOFC). It is fluorite structure widely known as oxygen ion conductors. Addition of carbonate salt into fluorite-based electrolyte is common to overcome low conductivity of CSZ as well as to decrease sintering temperature. Increase of ionic conductivity in the SOFC electrolyte is also influenced by presence of protons (H+), so it is called mixed-ion electrolytes. In this study, the effect of sintering temperature and carbonate content prepared from mixture of Li2CO3 and Na2CO3 on the relative density, ionic conductivity and microstructure of electrolyte and fuel cell performance was investigated. The sintered CSZ/carbonate samples were examined physically and electrochemically by using SEM, TEM, XRD, and EIS. The unique detail of nanostructure for CSZ/carbonate was investigated by TEM. The XRD is to observed peak associating with CSZ, Li2CO3, and Na2CO3, as well as its crystallinity. Moreover, the electrolyte resistance was measured by EIS so that the proton conductivity and oxygen conductivity of CSZ/carbonate can be calculated. The improvement of low-cost electrolyte material such as CSZ can be realized by providing protons pathway.

Micropaleontological Assemblages on December-2004 Tsunamigenic Sediments Record of Climate Variation Between Cuddalore and Nagapattinam, East Coast of India

Ninety-nine benthic foraminiferal species belonging to 41 genera, 26 families, 17 superfamilies and 5 suborders have been identified from 84 samples which were collected from beach (23 nos), offshore (24 nos), estuaries (8 nos), inland (23 nos) and one pit sample (6 nos), between Cuddalore and Nagapattinam in the tsunami affected coastal environment. Out of 99 species, only 20 species are living ones. The following species are appreciably distributed in different stations, namely Ammonia beccarii, Elphidiumcrispum, Rosalina globularis, Asterorotaliatrispinosa and Pararotalianipponica. The total distribution of foraminifera is higher at Cuddalore and Nagapattinam whereas at Pudupettai and Samadanpettai it is noticed in the lower order. Organic matter and living species show positive relation. No relationship is observed between dead species and the organic matter, which suggests that the dead species recorded in the sediment, must have been primarily drifted/transported as empty calcareous shells. From the sand/silt/clay ratios, it is inferred that the sediments are normally sandy in nature but silty sand dominates at deeper depths. Carbonate content establishes a positive correlation with all parameters. A fluctuation of salinity values in offshore regions indicates the influx of fresh water from Colleroon river. From the overall studies of foraminiferal distribution in this region, it may be inferred that the species distribution in the offshore region is mainly derived from the inner shelf region. To observe the earlier changes in climactic condition in marine environment mainly based on information from marine sediments. The collected samples from our study area marine sediments contain a variety of foraminifera, which archive climactic information from both planktonic and benthic assemblages and in their sedimentological compositions.

Effects of Modification and Co-Aging with Soils on Cd(II) Adsorption Behaviors and Quantitative Mechanisms by Biochar

In this study, original rice straw biochar and two KMnO4-modified biochars (pre- and postmodification) were prepared, which were all pyrolysed at 400℃. Premodified biochar had the largest Cd adsorption capacity, strongest acid and solute buffering capacity, which benefited from the increase of carbonate content, specific surface area and the emergence of Mn(II) and MnOx through modification. Original and premodified biochars were then conducted four types of aging process, namely, aging without soil, co-aging with acid (pH=5.00), neutral (pH=7.00) and alkaline (pH=8.30) soils, using an improved three-layer mesh method. The adsorption capacities of modified biochar were always larger than those of original biochar after aging processes. After four aging processes, Cd(II) adsorption capacities were basically in the order of aged biochar without soil > biochar co-aged with alkaline soil > biochar co-aged with neutral soil > biochar co-aged with acid soil, and KMnO4-modified biochar was always better than original biochar after co-aging with soils. The dominant adsorption mechanism of original and premodified biochars (fresh and aged) for Cd(II) was all the precipitation and adsorption with minerals (accounted for 58.55%~85.55%). In this study, we highlighted that biochar remediation for Cd should be evaluated by co-aging with soil instead of aging without soil participation.

Successive processes at quarry waste dumps of various ages

This work is dedicated to the study of the succession processes in quarries of different ages in the territory of the Russian Federation and neighbouring countries, namely, Kazakhstan and Ukraine. In selected soil samples from the areas studied, certain physical and chemical properties, the quantitative composition of microbial communities and the diversity of floral species from the quarries were studied. The pH values for the Kuzbass area were found to decrease to 4.8, and in the area of the younger quarries – Inguletsky and Sokolovsky – higher pH values were recorded. The basal soil respiration rate of the Kuzbass quarry was approximately 0.2 mg CO2/g/h. The CO2 carbonate content ranged from 0.05% to 0.6%. The microbial biomass in Kuzbass soil was from 0.87 to 5.10 μg C/g soil, while its quantity in other quarries was 6 times lower, which is associated with the relatively young age of these sites. The study of the diversity of floral species in the Kuznetsk coalfield identified 120 species of upper plants belonging to 34 families. Among them, cereals, legumes and mosses, lichens and algae were predominant. In the territory of Inguletsky and Sokolovsky quarries, the diversity of plant species was much poorer. In this regard, further research will focus on increasing the rate of succession and maintaining ecosystem stability by increasing the share of microorganisms. Also, the study of the possibility to accelerate the restoration of younger flora in the discharges of age careers at the expense of the mycorrhizal communities formation is of high relevance.

Effect of Spraying Glyphosate Herbicide on Solanum elaeagnifolium in Uncultivated Fields and on Physicochemical and Biological Soil Characteristics

Bakkour, F., A. El-Meamar and Z. El-Naser. 2021. Effect of Spraying Glyphosate Herbicide on Solanum elaeagnifolium in Uncultivated Fields and on Physicochemical and Biological Soil Characteristics. Arab Journal of Plant Protection, 39(4): 296-308. https://doi.org/10.22268/AJPP-39.4.296308 Glyphosate herbicide is used in uncultivated fields infested with Solanum elaeagnifolium plants several times a year in all Syrian governorates by the Ministry of Agriculture. This research aimed to study the effect of repeated spraying of glyphosate in uncultivated fields in five different locations in the Syrian governorates, Deir Ezzor (Tebni), Aleppo (Dakwani), Hama (Bostan AL-Omahat), Homs (ALZahoria) and Rural Damascus (Bohter) during the period 2017-2020, on the physiochemical and biological characteristics of the treated soils. Herbicide residues were measured in the leaves of the treated Solanum elaeagnifolium plants and in the soils surrounding the roots of the Solanum elaeagnifolium plants. It was found that the repetition of the pesticide spray 3 and 6 times during the study period did not alter the physical composition, salinity, pH and calcium carbonate content in all study locations. Whereas, spraying glyphosate 3 and 6 times increased the percentage of organic matter and phosphorus available, with a significant difference with the control. The values of available phosphorous after 6 pesticide spray applications reached 176, 203, 196, 227 and 205 mg/kg of soil in Deir Ezzor, Aleppo, Hama, Homs and Rural Damascus, respectively. In addition, repeated spraying with glyphosate of the treated soils led to increase the average general bacteria and fungi populations. These indicators were increased with the increase in the number of pesticide sprays applied. Furthermore, the pesticide residues increased in the soil and Solanum elaeagnifolium leaves with the increase in number of pesticide sprays. Pesticide residue values after 6 sprays were 1.72, 3.53, 4.89, 4.43 and 2.29 mg/kg of soil in Deir Ezzor, Aleppo, Hama, Homs and Rural Damascus locations, respectively. Keywords: Glyphosate, S. elaeagnifolium, residues, microorganisms, soil.

Water repellency decreases with increasing carbonate content and pH for different biocrust types on sand dunes

Biocrusts are biological communities that occupy the soil surface, accumulate organic matter and mineral particles and hence strongly affect the properties of the soils they cover. Moreover, by affecting water repellency, biocrusts may cause a preferential infiltration of rainwater, with a high impact on the formation of local water pathways, especially for sand dunes. The aim of this study is to shed light on the connections between water repellency and pH, carbonate and organic matter content in two dune ecosystems with different biocrust types. For this, we used contact angle measurements, gas volumetric carbonate determination and organic matter characterization via FT-IR and TOF-SIMS. In both ecosystems, moss-dominated biocrusts showed higher water repellency and higher amounts of organic matter compared to algal or cyanobacterial biocrusts. Surprisingly, the biocrusts of the two dune systems did not show differences in organic matter composition or organic coatings of the mineral grains. Biocrusts on the more acidic dunes showed a significantly higher level of water repellency as compared to higher carbonate containing dunes. We conclude that the driving factor for the increase in water repellency between cyanobacterial and moss-dominated biocrusts within one study site is the content of organic matter. However, when comparing the different study sites, we found that higher amounts of carbonate reduced biocrust water repellency.

Trifolium Repense L. Breeding In The Central Chernozem Region: Main Directions And Methods Of Work

Varieties and breeding samples of creeping clover Trifolium repense L. of lawn direction were studied in the nursery of competitive varietal trials. Using the methods of recurrent breeding involving local populations of creeping clover growing on chalk outcrops as initial forms, two varieties ‘Krasnoyaruzhsky’ and ‘Ilyok’ were obtained, as well as a new breeding sample PO 17/07. Varieties ‘Krasnoyaruzhsky’, ‘Ilyok’ and selection sample PO 17/7 are characterized by high seed productivity, the possibility of cultivation on soils with high carbonate content (burial of construction waste in an urban environment, reclamation of man-made-disturbed landscapes, etc.); high resistance to trampling. Seed yield over three years of tests in varieties ‘Krasnoyaruzhsky’, ‘Ilyok’ and breeding sample PO 17/7 significantly exceed the standard by an average of 24,6-26,8%; have uniform foliage at the level of 48-53%. Breeding sample PO 17/7 is planned to be submitted to the State variety testing.

Petrographic and geochemical features of Gimo marble, Gole area, Kurdistan Region, Iraq: constraints on its protolith's origin and depositional environment

It is essential to identify marbles' petrographic and geochemical characteristics to determine the palaeo-environmental settings where their carbonate protoliths formed. The petrogenesis of massive Gimo marbles in the Gole area, Kurdistan Region of northeast Iraq, was investigated in this study through a combination of field mapping, petrographic, and geochemical techniques. Petrographic examination of these marbles reveals that mineral compositions are similar in all samples, with both homeoblastic and mosaic textures occurring, in addition to opaque grains that provide evidence of mineralization. Geochemical analyses show that the average calcium carbonate content of the marble is 94.96%; hence, the marble is lithologically characterized as a pure calcite marble. In most samples, the silica content was below 2 wt.%, with high values related to quartz veinlets. A range of geochemical indices and Post-Archean Australian Shale (PAAS–normalized rare earth element (REE) patterns) suggest that the limestone protolith was deposited in a shallow, near-shore marine environment on a continental margin, with very low input of detrital material. The negative Ce anomalies indicate that the protoliths of the Gimo marbles were carbonate rocks of a sedimentary origin.

Climate, cryosphere and carbon cycle controls on Southeast Atlantic orbital-scale carbonate deposition since the Oligocene (30–0 Ma)

The evolution of the Cenozoic cryosphere from unipolar to bipolar over the past 30 million years (Myr) is broadly known. Highly resolved records of carbonate (CaCO3) content provide insight into the evolution of regional and global climate, cryosphere, and carbon cycle dynamics. Here, we generate the first Southeast Atlantic CaCO3 content record spanning the last 30 Myr, derived from X-ray fluorescence (XRF) ln(Ca / Fe) data collected at Ocean Drilling Program Site 1264 (Walvis Ridge, SE Atlantic Ocean). We present a comprehensive and continuous depth and age model for the entirety of Site 1264 (∼ 316 m; 30 Myr). This constitutes a key reference framework for future palaeoclimatic and palaeoceanographic studies at this location. We identify three phases with distinctly different orbital controls on Southeast Atlantic CaCO3 deposition, corresponding to major developments in climate, the cryosphere and the carbon cycle: (1) strong ∼ 110 kyr eccentricity pacing prevails during Oligocene–Miocene global warmth (∼ 30–13 Ma), (2) increased eccentricity-modulated precession pacing appears after the middle Miocene Climate Transition (mMCT) (∼ 14–8 Ma), and (3) pervasive obliquity pacing appears in the late Miocene (∼ 7.7–3.3 Ma) following greater importance of high-latitude processes, such as increased glacial activity and high-latitude cooling. The lowest CaCO3 content (92 %–94 %) occurs between 18.5 and 14.5 Ma, potentially reflecting dissolution caused by widespread early Miocene warmth and preceding Antarctic deglaciation across the Miocene Climatic Optimum (∼ 17–14.5 Ma) by 1.5 Myr. The emergence of precession pacing of CaCO3 deposition at Site 1264 after ∼ 14 Ma could signal a reorganisation of surface and/or deep-water circulation in this region following Antarctic reglaciation at the mMCT. The increased sensitivity to precession at Site 1264 between 14 and 13 Ma is associated with an increase in mass accumulation rates (MARs) and reflects increased regional CaCO3 productivity and/or recurrent influxes of cooler, less corrosive deep waters. The highest carbonate content (%CaCO3) and MARs indicate that the late Miocene–early Pliocene Biogenic Bloom (LMBB) occurs between ∼ 7.8 and 3.3 Ma at Site 1264; broadly contemporaneous with the LMBB in the equatorial Pacific Ocean. At Site 1264, the onset of the LMBB roughly coincides with appearance of strong obliquity pacing of %CaCO3, reflecting increased high-latitude forcing. The global expression of the LMBB may reflect increased nutrient input into the global ocean resulting from enhanced aeolian dust and/or glacial/chemical weathering fluxes, due to enhanced glacial activity and increased meridional temperature gradients. Regional variability in the timing and amplitude of the LMBB may be driven by regional differences in cooling, continental aridification and/or changes in ocean circulation in the late Miocene.