Increase In Ca Concentration Research Articles

Rodingites from the Veria-Naousa ophiolite (Greece): Mineralogical evolution, metasomatism and petrogenetic processes

In the Veria-Naousa ophiolitic complex (north Greece), rodingite appears mainly in the form of cross cutting dykes within serpentinised peridotites. It is distinguished into three types, based upon the provenance of its protoliths, textural characteristics, mineralogical assemblages and geochemical affinities. Type I rodigites were derived from boninitic diabasic protoliths and their mineralogical assemblage include garnet + clinopyroxene + chlorite. Type II rodingites were formed at the expense of gabbroic precursors, comprising clinopyroxene + garnet + vesuvianite ± quartz, whereas Type III rodingites replaced diabasic tholeiitic protoliths comprising of garnets + vesuvianite + clinopyroxene + chlorite. Rodingitisation resulted in desilification, decrease of alkalies, Al, Fe, Mg and increase in Ca contents. In Type I rodingites the MREE (middle rare earth elements) and HREE (heavy rare earth elements) were slightly reduced. Type II rodingites experienced LREE (light rare earth elements) depletions, whereas MREE and HREE remained fairly stable. Restricted mobility of REE in Type III rodingites is assigned to shallow-level rodingitisation under decreasing pH.Rodingitisation occured in two distinct stages at fore-arc settings. The first stage occured under mildly oxidising conditions and enhanced CO2/H2O ratios. This stage affected the protoliths of all rodingite types. The second rodingitisation stage occured under more oxidising conditions and lower CO2/H2O ratios, which corresponds to the exhumation stage of the serpentinite-rodingite formations. Types II and III rodingites were subjected to further rodingitisation under the increasing influence of slab-derived hydrous phases at shallower depths, leading to the formation of late-stage andradite and vesuvianite. All stages of rodingitisation are estimated to have occurred under relatively moderate temperatures and pressure (~300 to 450 °C; ~2–6 kbar respectively).

Pressure and concentration effects on intermineral calcium isotope fractionation involving garnet

To better understand the behaviors of calcium (Ca) isotopes during igneous and metamorphic processes that differentiate the Earth and other rocky planets, we investigated the effects of pressure and Ca/Fe concentration on the average CaO bond length and the reduced partition function ratio of 44Ca/40Ca (103ln44/40Caβ) in garnet using first-principles calculations. Our calculations show that (1) the average CaO bond length increases and 103ln44/40Caβ decreasing (approximately 0.41‰ at 1000 K from a Ca/(Fe + Ca + Mg) of 1/24 to 12/12) with increasing Ca concentrations. In contrast to orthopyroxene and forsterite, whose CaO bond lengths and 103ln44/40Caβ are sensitive to Ca concentrations only in narrow range, the garnet CaO bond length and 103ln44/40Caβ vary with Ca concentrations in wide ranges. (2) The average CaO bond length increases and 103ln44/40Caβ decreases with increasing Fe concentrations (by 0.12‰ at 1000 K, FeO content of 12.4 wt%). (3) The average CaO bond length decreases by ~0.014 Å, and 103ln44/40Caβ increases by 0.1‰–0.2‰ at 1000 K when the pressure increases from 0 to 3 GPa. (4) However, the pressure effect on 103ln44/40Caαgarnet–clinopyroxene is insignificant.Using our new results of the effects of pressure and Ca/Fe concentration on 103ln44/40Caαgarnet–clinopyroxene, we evaluated the observed difference in Ca isotope compositions between garnet and clinopyroxene in natural samples. Most have reached equilibrium, whereas some samples exceed our prediction, which might reflect the majorite effect or kinetic fractionation.

Integrated interpretation of pXRF data on ancient nephrite artifacts excavated from Tomb No.1 in Yuehe Town, Henan Province, China

Previous studies of ancient jade using portable X-ray fluorescence (pXRF) have mostly focused on mineral identification, alteration status and provenance determination. It is usually used as an auxiliary instrument for spectroscopic detection with finer resolution. However, there is no substitute for the efficiency and stability of pXRF in-situ non-destructive analysis, which is less affected by the test environment. The scale of the data from the pXRF analysis did not allow for a more in-depth interpretation of ancient jade in the past. In this study, pXRF has been carried out for a total of 112 pieces of nephrite artifacts unearthed from the Yuehe tomb No.1 in Nanyang City, Henan Province, Central China. Certain patterns become clearer as the size of the data increases. The coefficient of variation, cluster analysis and correlation analysis can be used to separate elements into different assemblages, revealing whether the elements are from the primary and impurity minerals of nephrite itself, from the burial microenvironment in the soil, or even from other specific sources. In addition, most of the secondary whitening occurring in the batch of nephrite are accompanied by an increase in Ca content, confirming the previously refuted theory of calcification. More importantly, the principal component analysis of the twin nephrite artifacts suggests visually indistinguishable elemental changes caused by secondary changes, which may lead to misjudgment of ancient nephrite provenance using elemental data.

Comparative analysis of changes in density and mineral composition of bone tissue on the background of experimental diabetes mellitus and opioid influence

Background. The study of bone tissue includes two directions – the study of patterns of structural reconstruction and clarification of the dynamics of mineral composition. Bone tissue reacts differently to the influence of exogenous and endogenous factors, but there is always a violation of the bone microarchitecture, its density and mineral composition. Purpose. Investigation and comparison of changes in bone density and its mineral composition on the background of experimental diabetes mellitus and long-term opioid influnce. Materials and methods. The study was performed on 25 white sexually mature nonlinear male rats, weighing 160–270 g, aged 5–7 months. The duration of the experiment was 6 weeks. Insulin-dependent form of type I diabetes mellitus was simulated by the administration of streptozotocin. Simulation of the long-term effects of opioids on the body was carried out by administering preparation Nalbuphine (Rusan Pharma LTD, India). Bone density was determined by the means of dental radiovisiography apparatus. The unit of measurement is the conventional unit of grayness. The mineral composition was investigated by atomic absorption spectral analysis of bone fragments on an atomic absorption spectrophotometer using propane-butane-air flame. The content of calcium, phosphorus and magnesium was investigated. The concentration of the elements was expressed in mg/g. Results. The data of radiovisiographic research showed that in experimental diabetes mellitus the density of the bone tissue of the mandible body decreases, and in the cases of long-term opioid use – increases. The decrease in density indicates the development of osteopenia, due to a decrease of calcium quantity and of the Ca/P index on the background of increasing levels of phosphorus and magnesium and Mg/Ca index. The increase in density is due to an increase in the absolute content in bone tissue of Ca, P and Mg, and Ca/P index, which confirms the increased mineralization of bone, the acceleration of metabolic processes of which is stimulated by the Mg content increase. Among all the studied ele-ments, only the ratio of absolute indicators of Ca content coincides with the ratio of its specific shares and bone density indicators. A similar ratio is determined for the Ca/P index. Conclusions. The decrease in bone density of the mandible on the background of experimental diabetes mellitus is likely to develope due to calcium content and Ca/P index decrease with increase in phosphorus and magnesium content and Mg/Ca index; and an increase in bone density on the background of long-term use of opioid drugs is caused by the increase in Ca, P and Mg content, as well as Ca/P index.

Synthesis and Characterization of Blended Cellulose Acetate Membranes.

The casting and preparation of ultrafiltration ZnO modified cellulose acetate membrane (CA/ZnO) were investigated in this work. CA membranes were fabricated by phase inversion using dimethylformamide (DMF) as a solvent and ZnO as nanostructures materials. Ultrafiltration (UF) performance, mechanical stability, morphology, contact angle, and porosity were evaluated on both CA- and ZnO-modified CA samples. Scanning electron microscopy (SEM) was used to determine the morphology of the membranes, showing different pore sizes either on rough surfaces and cross-sections of the samples, an asymmetric structure and ultra-scale pores with an average pore radius 0.0261 to 0.045 µm. Contact angle measurements showed the highest hydrophobicity values for the samples with no ZnO addition, ranging between 48° and 82.7° on their airside. The permeability values decreased with the increasing CA concentration in the casting solution, as expected; however, ZnO-modified membranes produced lower flux than the pure CA ones. Nevertheless, ZnO modified CA membranes have higher surface pore size, pore density and porosity, and improved surface hydrophilicity compared with pure CA membranes. The results indicated that the incorporated nano-ZnO tends to limit the packing of the polymer chains onto the membrane structure while showing antifouling properties leading to better hydrophilicity and permeation with consistent UF applications.

Enhanced Mechanical Properties and Isotropy of Mg-2Al-0.8Sn Alloy through Ca Addition.

Calcium (Ca), with abundant and cheap reserves, is a potential element to facilitate the further application of Mg-Al-Sn based alloys. Here, effects of Ca content on the microstructure and tensile properties of Mg-2.0Al-0.8Sn (wt.%) alloys were systematically studied. The experimental results illustrated that the strength, ductility and isotropy of the alloys improved simultaneously with the increase of Ca content. The better ductility and isotropy could be contributed to the weakened texture via particle stimulation nucleation mechanism. The higher strength benefited from the combination of finer grains, more precipitates and residual dislocation density. Eventually, the Mg-2.0Al-0.8Sn-0.5Ca (wt.%) alloy showed the best room-temperature balance of strength and ductility with a yield strength of ∼226.0 MPa, an ultimate tensile strength of ∼282.4 MPa and a fracture elongation of ∼20.2%, which has huge potential as an applicable low-cost high-performance magnesium alloy.

Effect of calcium solubility on structural, microstructure and magnetic properties of SrFe12O19

The synthesis of Sr1-xCaxFe12O19 (x = 0.0–1.0 at increments of 0.1) samples is reported via a sol-gel auto-combustion process. XRD data for Sr1-xCaxFe12O19 samples calcined at different temperatures indicates a) single-phase formation up to x = 0.20 in samples calcined at 900 °C, b) an increase in calcium solubility to 50 atomic % (x = 0.50) at 1200 °C, c) a decrease in lattice parameters and cell volume with increasing ‘x’ and d) the presence of segregated α–Fe2O3 phase for x > 0.50 at 1200 °C and for x ≥ 0.20 at 900 °C. As the maximum Ca solubility in SrM (SrFe12O19) phase has been observed at 1200 °C, most of the other characterizations have been performed on these samples only. An increase in grain size with ‘x’ was revealed in FESEM micrographs. Magnetic measurements show that in the x = 0.50 sample the maximum saturation magnetization (Ms) value is ≈ 70.67 emu/g. Coercivity (Hc) decreases monotonically, with an increase in Ca content in SrM (SrFe12O19), from 3822 Oe (x = 0.00) to 2045 Oe (x = 0.50). Among the samples calcined at different temperatures, coercivity (Hc) decreases monotonically from 5650 Oe to 3128 Oe with an increased calcination temperature for samples of x = 0.20. The samples could be vital for magnetic recording and applications as permanent magnets due to their excellent magnetic properties.

Growth of tomato plantlets in soilless culture, enriched with egg shell waste and algae

In this research, it was aimed to use the Chlorella Vulgaris algae, and eggshell waste (ESW) as different mineral sources for tomato plant nutrition in soilless culture. Algae is seen as safe, sustainable energy source. Egg shell waste is known to be valuable for high calcium content and minerals therefore, has been considered as mineral enrichment source. Although there are several papers on the soil nutrition, there is not as much information on eggshell waste and algae use for plant production in soilless culture. In the controlled atmosphere of the laboratory, a set-up was constructed for pumping the liquid medium (hydroponics) circulating in the tubes holding the tomato plantlets. The liquid nutrient solutions used for soilless culture treatments were media enriched with algae, enriched with ESW and blank (hydroponic only). Research was conducted for 3 months, the final weight of harvested tomatoes and mineral uptake of the plant (stalk and tomato) for different treatments were measured. Algae added medium gave higher results in tomato weight, than ESW added and blank treatments. Results showed that algae and ESW addition led to increased Ca content in harvested tomato, as well as minerals such as B, K, Mg, and Zn. The results were as expected in terms of increase in mineral contents, but the statistics showed no significant difference between treatments.

Geochemical processes in the groundwater of Soubré, Ivory Coast, West Africa: Evidence from 14C, 13C, 18O, 2H and major ions

Characteristics of the bedrock groundwater in the southwestern (SW) Ivory Coast (IC) (5–6°N, 4–7°W) are geochemically less known compared to those in the eastern part of the country. Several main cash crops, such as cocoa, coffee, rubber and palm oil, started being grown in this area twenty years ago because of the migration of agricultural activities from the East to the West of IC; this migration of agricultural activites was tied to climate variability. Within these large land use areas, food crops such as plantain bananas, yams, rice, maize, and vegetables are also grown. In this work, the mineralisation and groundwater pollution from East IC to West IC are studied within groundwater of the Archean and Paleoproterozoïce bedrock aquifers located in the SW IC. Stable isotopes ratios (δ18O, δ2H and δ13C), radiocarbon activity (A14C) and chemical contents (major ions) were measured on a set of 23 groundwater samples. In SW IC, the residence times calculated by an exponential mixing model (EMM) and a dispersion model (DM) with Dispersion Parameter values of 0.05 and 0.5 reveal that the oldest groundwater is located in the aquifer of migmatitic and granulitic gneiss (MiGn aquifer). Recent groundwater is located in the metagranitoid (MetGr) and the metasedimentary rocks (MetSe) aquifers. The most appropriate model to compute residence times is EMM because of the highest proportion of recharge in accordance with the nitrate content in groundwater after 1958, the beginning of Ivorian deforestation. However, this model lead to an overestimate of the residence time of groundwater particularly high in NO3. The oldest age of MiGn groundwater according to EMM calculation is ∼5 ka BP. The MiGn aquifer is less renewed (mean annual renewal rate of 0.03%) followed by those of MetSe (∼2.5 ka BP) and MetGr (∼2 ka BP), with mean annual renewal rates of 0.09% and 0.012%, respectively. Groundwater mineralisation is mainly governed by the hydrolysis of Al-silicates minerals and cultivation practice linked to K and N-fertilisers use, which leads to an increase of Ca, Mg and Na content. The values of TDS ranged from 49.4 to 720.4 mg L−1, which indicates the chemical characteristics of fresh water in SW IC. Most of the studied area groundwater are evaporated, likely due to both climate variability since the last 5 ka BP, delayed infiltration of rainwater which would be caused by impervious sediments covering the hard rock aquifers and agricultural practices affecting the most recently recharged groundwater. River water recharge from irrigation in cultivated areas may be possible. The groundwater with low 14C activities (64.33 pMC) has high residence times and is depleted in 13C content, while that with high 14C activities (99.58 pMC) is enriched in 13C content. This demonstrates that vegetation cover changed from C3 plants or forest (−23.9‰) to C4 plants, savannah or cultivation plants (−12.5‰) similar to those found in the southeastern IC.

Use of fumaric acid as a feed additive in quail's nutrition: its effect on growth rate, carcass, nutrient digestibility, digestive enzymes, blood metabolites, and intestinal microbiota

To investigate the effects of dietary fumaric acid (FUA) on performance, carcasses, nutrient digestibility, blood metabolites, digestive enzymes, and cecal microbiota in Japanese quail chicks. Three hundred unsexed Japanese quail (1-wk-old) were randomly assigned to 5 groups. Supplementation of FUA in the diet of Japanese quail chicks exhibited a significant improvement in growth performance through the different experimental periods studied compared with those receiving unsupplemented one. The digestibility of crude protein (CP) and metabolizable energy (ME) were improved with 10 and 15 g/kg FUA, respectively. Apart from lipase enzyme, birds fed 5 and 15 g/kg FUA recorded higher activity of amylase. There were no significant changes among experimental groups on the relative weights of carcass, gizzard, heart, and dressing. Dietary supplementation of FUA at different levels (P> 0.05) increased total protein (TP) and globulin (GLB) concentrations and A/G % compared with control group. A significant (P < 0.01) decrease in plasma low density lipoprotein (LDL) and total cholesterol (TC) levels and increase in high density lipoprotein (HDL) concentrations were observed in chicks fed with FUA containing diets. Immunoglobulin G (IgG) (P = 0.0026) and M (IgM) (P = 0.0007) levels were greater in groups treated with either 10 or 15 g FUA/kg diet. A significant increase in plasma Ca concentration was noticed in chicks received 15 g FUA/ kg compared with the other groups. Quail chicks received diets containing FUA at different levels exhibited reduced cecal count of coliform, E. coli, and Salmonella as compared with control group. In conclusion, supplementation of fumaric acid (especially 15 g/kg diet) in quail chick diets improved their growth, digestibility of nutrients, immune response, antioxidant status, digestive enzyme, and intestinal health.

Fermentation of Persea americana Seed Flour Using Lactobacillus plantarum and Investigate Its’ Effect on Nutritional Quality

This study aims to investigate the fermentation of Avocado seed flour using Lactobacillus plantarum. Proximate composition and most important mineral contents of Avocado seed flour after fermenting for 24, 48 and 72 h were compared with dry unfermented Avocado seed flour. Avocado seed flour fermented for 72 h had significant increase (p&lt;0.05) of crude protein content from 6.42±0.08% to 9.26±0.28%. Mineral contents were determined by Atomic Absorption Spectrophotometer. Ca, Mg, Fe contents of dry unfermented Avocado seed flour were 208.89±0.3 μg/g, 99.05±0.01 μg/g, 9.04±0.01 μg/g and fermented Avocado seed flour (72 h) were 227.06±0.050 μg/g, 189.22±0.33 μg/g, and 18.11±0.006 μg/g respectively. There is a significant increase (p&lt;0.05) of Ca, Mg and Fe content of fermented (72 h) Avocado seed flour. Fermentation of Avocado seed flour for 72 h enhance the nutritional quality.

Hybrid hematite/calcium ferrite fibers by solution blow spinning: Microstructural, optical and magnetic characterization

Iron oxide and Ca-doped ferrite fibers were successfully prepared via Solution Blow Spinning (SBS). Fibers with several calcium contents (nFe/nCa = 3.0, 5.2, and 20.0 atomic ratio) were prepared after dissolving polyvinylpyrrolidone and Fe and Ca nitrates in an acidic aqueous solution, followed by SBS spinning and calcination at 800 °C. The morphological, structural, optical, vibrational, and magnetic properties of the fibers were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), Mössbauer spectroscopy, and magnetometry. The Rietveld refinement revealed Ca-doped fibers consisting of a mixture of Fe2O3, CaFe2O4, and Ca3.6Fe14.4O25.2 crystalline phases. The Mössbauer spectra at 300 K showed a sextet belonging to the hematite phase and two doublets belonging to the calcium-related phases. Measurements at low temperatures showed a transition at 181.6 K attributed to Ca ferrite. The hematite fibers showed a saturation magnetization (Ms ~ 0.75 emu/g) relatively higher than the bulk α-Fe2O3 (Ms = 0.3 emu/g). The saturation magnetization increased from 3.6 to 6.4 emu/g with increasing Ca content.

Limestone and gypsum reapplication in an oxisol under no-tillage promotes low soybean and corn yield increase under tropical conditions

Limestone and gypsum combined use in no-tillage (NT) systems can favor soil acidity correction and improve nutrient availability in-depth with positive effects on crop production. There are still doubts about the necessity to restart the NT when the soil’s natural acidity was not corrected properly. The study evaluated i) the changes in the vertical distribution of nutrients and the acidity attributes in the soil solid phase, ii) the crop yields resulting from limestone reapplication strategies, associated or not with superficial gypsum application, and iii) the need to restart the NT system, with limestone incorporation to correct the re-acidification of an Oxisol in the Cerrado biome. Six treatments were evaluated, following the NT maintenance: i) no limestone reapplication and no gypsum application (NL), ii) superficial gypsum application (NL+), iii) superficial limestone reapplication (SL), and iv) superficial limestone reapplication and superficial gypsum application (SL+); or restarting the NT: v) limestone reapplication and incorporation (IL), and vi) limestone reapplication and incorporation followed by superficial gypsum application (IL+). Seven years after the experiment implementation, the soil was sampled in eight stratified layers down to the 50 cm depth in the experimental plots and under the Cerrado natural vegetation (CNV). The chemical attributes related to soil acidity, nutrient availability, and the soybean and corn yields were evaluated. The soil under CNV has lower pH and greater aluminum saturation (Alsat) than the NL treatment, whose natural potential acidity was corrected 36 years ago and remained without limestone reapplication for 11 years. Such results indicate that the soil re-acidification process is slow. Superficial limestone reapplication (SL and SL+) reduced soil Alsat down to 25 cm but did not neutralize it completely. Limestone incorporation (IL and IL+) had little effect on Alsat distribution in-depth when compared to superficial limestone application. Gypsum application increased Ca content and lead to Mg displacement in soil depth, but did not affect Al dynamics, nor the crop yields. The effects of limestone and gypsum reapplication on the soil surface under NT provided a greater nutrient accumulation in the soil superficial layer, especially Ca and Mg. Soybean showed a low but positive yield response to the limestone reapplication, regardless of the method (average yield increase of 252 kg ha−1 year−1), but corn yield was less affected. There is no need to incorporate the limestone neither to apply gypsum in agricultural lands that had their natural acidity corrected properly in the past.

Catalyst and Elemental Analysis Involving Biodiesel from Various Feedstocks

The world is currently faced with the depletion of fossil fuel energy sources and their use is associated with environmental pollution. This has triggered the need to seek alternative energy sources that are renewable, sustainable and environmentally benign. Biodiesel, an alternative fuel of interest, is obtainable from biomass feedstocks. In existing biodiesel fuel, there are concerns that it is a contaminant due to its elemental contents, which over time also affect its quality. This study aimed to investigate the influence of a bifunctional catalyst on the conversion of free fatty acids and the elemental composition of biodiesel obtained from waste oils of sunflower and palm feedstocks. The synthesised catalyst was characterised using BET, XRD, FTIR and SEM while ICP-OES and Rancimat were used for elemental contents and oxidation in feedstocks and biodiesels. The effect of Cu, Zn and Fe metals on the stability of synthesised biodiesel was further studied. The catalyst showed characteristics of bifunctionality with improved textural properties necessary for the conversion of high free fatty acids feedstocks to biodiesel, despite increasing Ca content within the produced biodiesel. Sunflower biodiesel showed superior fuel quality, although palm biodiesel had more oxidation stability. An increase in the concentration of metals decreased the induction period, with Cu and Fe being more effective than Zn metal.

Magnetocaloric properties and analysis of the critical point exponents of Pr0.55CaxSr0.45-xMnO3 (x = 0.00, 0.05, 0.1 and 0.2) at PM-FM phase transition

The polycrystalline manganite Pr0.55CaxSr0.45-xMnO3 (x = 0.00, 0.05, 0.1, and 0.2) has been prepared by the solid state reaction technique to investigate its crystal structure, magnetic, and magnetocaloric properties. Critical behaviour around PM-FM phase transition has also been analyzed through various methods including modified Arrott plots (MAP), and critical isotherm analysis of Pr0.55CaxSr0.45-xMnO3 (x = 0.00, 0.05, 0.1, and 0.2). XRD analysis reveals that all the samples are found to be crystallized in the orthorhombic system with Pnma space group and lattice parameters a, b and c as well as the cell volume are found to decrease with increasing Ca (x) content. Microstructure is observed with the field emission scanning electron microscopy (FESEM) photograph and elemental compositions are determined by energy dispersive X-ray diffractometer (EDX). Temperature and field dependent magnetization measurement disclose that all the samples undergo second-order FM to PM phase transition but the Curie temperature (TC) value decreases from 290 K to 245 K with the increase in Ca (x) content from 0.00 to 0.20. The magnetocaloric effect (MCE) in terms of maximum entropy change, (-ΔSm)max and relative cooling power (RCP) was calculated from isothermal magnetization measurements around TC, using Maxwell’s thermodynamic relations. Both (−ΔSm)max and RCP increases with increasing Ca content suggests the suitability of this compound as a potential solid state refrigerent. Contribution of itinerant electron in the entropy change is found from modulating MCE with Landau theory of phase transition.

The Impact Assessment of CuO Nanoparticles on the Composition and Ultrastructure of Triticum aestivum L.

In the present study, the effects of copper oxide nanoparticles (CuO NPs) on bioactive compounds, the ultrastructural modifications which can occur, and elemental content of wheat were investigated. Changes in the wheat plants grown in presence or absence of CuO NPs were estimated. The application of CuO NPs decreased the amounts of chlorophylls and carotenoids and increased the amounts of polyphenols and antioxidant capacity. Ultrastructural analysis showed that the plants treated with CuO NPs were negatively affected. Soil amending completely inhibited the accumulation of seventeen elements, while K, Br, Al, and Zn were accumulated and Cl, Na, Ba, and Sr content decreased in wheat samples, regardless of the type of NPs applied. The application of chemically obtained NPs induced the most significant changes, completely blocking the assimilation of Fe, Mo, As, Sb, and Sm, and favoring much higher accumulation of Br than biogenic NPs. The decrease in chlorophylls and carotenoids is correlated with increase in antioxidant capacity, and occurs with increase of Mo, Al, Mg, K, Zn, and Ca content. The behavior of total polyphenols is correlated with Br content, and antagonist to Al behavior. From the point of view of bioactive compounds, the most affected plants were those that grew in the presence of CuO-NP-cel, while from the point of view of elementary analysis, the most affected plants were those grown in the presence of CuO-NP. By corroborating the obtained results, it was found that the CuO NPs have a negative effect on wheat plants.

Effect of Ca content and rheo-squeeze casting parameters on microstructure and mechanical properties of AZ91−1Ce−xCa alloys

The microstructure, mechanical properties and flame resistance behavior of the AZ91−1Ce alloys with different Ca additions were firstly investigated. Then, the effect of processing parameters, including applied pressures and rotation speeds, on the microstructure and mechanical properties of the rheo-squeeze casting AZ91−1Ce−2Ca alloy was studied. The results indicate that with the increase of Ca content, the microstructure is refined and the flame resistance of the AZ91−1Ce−xCa alloys increases. But when the Ca content exceeds 1 wt.%, with the Ca content increasing, the mechanical properties of the AZ91−1Ce−xCa alloys reduce rapidly. For rheo-squeeze casting process, the increase of applied pressure and rotation speed can both bring about significant refinement in the microstructure of the AZ91−1Ce−2Ca alloy and reduction of the porosity, so the mechanical properties increase. Compared to conventional casting, the AZ91−1Ce alloy with the addition of 2 wt.% Ca by rheo-squeeze casting not only guarantees the oxidation resistance (801 °C), but also improves mechanical properties.

In-situ layered double hydroxides on Mg−Ca alloy: Role of calcium in magnesium alloy

Mg−Al layered double hydroxides (LDHs), produced on cast Mg−xCa (x=0.5, 0.8, 2.0, wt.%) alloys by an in-situ growth method, showed good corrosion resistance compared to the bare magnesium substrate. The influence mechanism of the second phase (Mg2Ca) on LDHs production was investigated. Increasing Ca content increased the amount of Mg2Ca, decreasing the grain size and the corrosion rate of the alloys. The increased amount of the second phase particles and the grain refinement promoted the growth of LDHs, and thus led to the decreasing of corrosion rate of the Mg−xCa alloys with LDHs. A higher Mg2Ca amount resulted in forming fluffy LDHs. Due to the dual effects of the second phase (Mg2Ca) for LDHs growth and microgalvanic corrosion, LDHs/Mg−0.8Ca showed the lowest corrosion rate.

High-resolution records of anthropogenic activity and geohazards from the reservoir of Sun Moon Lake, Central Taiwan

Sun Moon Lake is the first dam reservoir constructed in Taiwan with the capability of generating hydroelectricity satisfying the whole Taiwan need during the Japanese colonial period since 1934 CE. Now, the Sun Moon Lake is one of the biggest hydropower stations in Taiwan and has become an important touring area. During World War II (1944–1945 CE), the hydroelectric power plant at Sun Moon Lake was bombed by the U.S. air force, which caused severe damage to the dam structure. More recently, the dam structure was also damaged during the 1999 CE Chi-Chi earthquake whose epicenter is nearby in the Nantou County. A suite of cores were taken from both Sun Lake and Moon Lake, and two selected cores, Sun 2–1 and SM 16 4–3, from Sun Lake were detailed studied with multiple analyses, including X-ray imaging, magnetic susceptibility, visible spectrophotometry, X-ray fluorescence (XRF) scanning, and mineral analysis. We discovered that the increase of Ca content in the sediments not only clearly indicates when the dam was constructed at Sun Moon Lake but also records evidence of structure repairs after both the World War II bombing and the Chi-Chi earthquake. Additionally, the yellow turbidite, X-ray image, and low-Ca signals in Core Sun 2–1 strongly correlate to the typhoon events that caused severe floods in the watershed of Zhuoshui River. The turbidite layers caused by the 1963 Gloria Typhoon are also characterized by conspicuous high peak of Fe/Mn in both cores. This study shows that XRF scanning results are useful for recognition of human activity and for high precipitation event correlation. Moreover, the appearance of charcoal layers shows evidence of forest burning and slash-and-burn activities by humans during the past 4,000 years back to the Middle Neolithic Age.

Polygenic Nature of Olivines from the Ultramafic Lamprophyres of the Terina Complex (Chadobets Upland, Siberian Platform) Based on Trace Element Composition, Crystalline, and Melt Inclusion Data

Olivine from the deep mantle-derived rocks, such as ultramafic lamprophyres, carries important information about the composition of the mantle source, the processes of mantle metasomatism, the origin of specific silicate-carbonate melts, as well as the composition and mechanisms of crystallization of these rocks. Textures and compositions of olivine from the carbonate-rich ultramafic lamprophyres (aillikites) of the Terina complex, along with their mineral and melt inclusions, exposed that olivines have different sources. Two populations of olivines were considered: macrocrysts (&gt;1 mm) and groundmass olivines (&lt;1 mm). Groundmass olivines are phenocrysts and characterized by weak variations in Mg# (84–86.5), a sharp increase in Ca and Ti contents, and a decrease in Ni and Cr from core to rim. They have higher concentrations of Li, Cu, Ti, and Na compared to macrocrysts. Among the macrocrysts, the following populations are observed: (1) high-Mg olivines (Mg# 89–91) with high Ni and low Ti contents, which are interpreted as xenocrysts from the slightly depleted lherzolite mantle; (2) high-Ca olivines (Mg# 84–88, CaO 0.13–0.21 wt %), which have patterns similar to groundmass olivines and are interpreted as cumulates of early portions of aillikite melt; (3) macrocrysts with wide variations in Mg# (73–88), low CaO contents (0.04–0.11 wt %), and positive slope in Ca vs. Al and negative slope in Ca vs. Mn, which are interpreted as disintegrated megacrysts from the Cr-poor megacryst suite. The megacryst suite could have been formed in the pre-trap period during the melting of the metasomatized subcontinental lithospheric mantle (SCLM). The aillikite melt evolution is traced by secondary melt inclusions in olivine macrocrysts: early phlogopite-diopside-calcite-apatite association, containing Ti-magnetite and ilmenite, is followed by an association with magnetite and sulfides (pyrrhotite and pentlandite); finally, at a late stage, inclusions with a predominance of Ca-Na-carbonates and sulfates and enriched in U, Th, Y, REEs, Sr, and Ba were captured.