Variations In Manganese Content Research Articles

Yb3+-activated phosphate glasses melted with MnCO3 for solar spectral conversion

This paper reports on the physical and optical properties of phosphate glasses containing red-emitting Mn2+ and near-infrared (NIR)-emitting Yb3+ ions of interest for solar spectral conversion. The glasses were prepared by melting with 50P2O5-(48 – x)BaCO3-2Yb2O3-xMnCO3 (x = 0, 1, 2, 3, 4 mol%) formulas, and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), UV-Vis-NIR spectrophotometry, and photoluminescence (PL) spectroscopy. The glasses were X-ray amorphous with the various characteristic features of phosphate glasses being evident in the FT-IR spectra. The thermal properties of the co-doped glasses assessed by DSC appeared similar despite the variation in manganese content. The optical absorption spectra supported the occurrence of Mn2+ ions while Mn3+ was detected at high MnCO3 content. The NIR absorption due to Yb3+ ions was nonetheless consistent with the fixed Yb2O3 content. The PL evaluation showed that sensitized Yb3+ PL was attained under Mn2+ excitation at 410 nm where the NIR emission increased with MnCO3 content in connection with Mn2+ → Yb3+ energy transfer. However, the NIR emission output realized with 4 mol% MnCO3 was just marginally higher than the obtained with 3 mol% MnCO3. On the other hand, the red Mn2+ emission was highest for 3 mol% MnCO3. Thus, considering the optimized red and NIR emissions while minimizing absorption by Mn3+, the Yb-containing glass melted with 3 mol% MnCO3 was put in perspective with the concept of solar spectral conversion.

Mechanical characterization and optimization of heat treatment parameters of manganese alloyed austempered ductile iron

Austempered Ductile Iron (ADI) belongs to the family of cast irons whose mechanical properties are altered using austempering heat treatment process. The objective of this paper is to study the effects of heat treatment parameters on manganese alloyed ADI. Hence, austenitization temperature, austempering temperature and austempering time are taken as the control variables along with the manganese content in the material. The effects of heat treatment are studied by measuring the ultimate tensile strength and the hardness of the material. The regression equations are developed to relate the various parameters under study. The microstructures of the specimen reveal that retained austenite content increases with increase in manganese and results in decrease in hardness of the material. The statistical analyses indicate that the austempering temperature is the major factor affecting the variation in hardness and tensile strength with 74.5 % of contribution within the range of values whereas, variation in manganese content does not have significant effect on hardness within the investigated composition range in the material.

Variations in glacial and interglacial marine conditions over the last two glacial cycles off northern Greenland

Abstract Five sediment cores from the Lomonosov Ridge and the Morris Jesup Rise north of Greenland show the history of sea-ice coverage and primary productivity over the last two glacial cycles. Variations in Manganese content, benthic and planktonic foraminifera, bioturbation, and trace fossil diversity are interpreted to reflect differences in sea-ice cover and sediment depositional conditions between the identified interglacials. Marine Isotope Stage (MIS) 1 and MIS 2 are represented by thin (

Unravelling the structural and chemical features influencing deformation-induced martensitic transformations in steels

A combination of Electron Back-Scattered Diffraction (EBSD) and high-sensitivity Electron Probe Micro-Analysis (EPMA) was used to correlate the changes in microstructural features upon deformation with local chemical composition in Transformation-Induced Plasticity steels. A novel cleaning procedure was developed that allows complete monitoring of transformation and deformation processes in relation to the local crystal structure, microstructure and chemical composition. Here we show direct evidence that local variations in manganese content enable a gradual transformation of the retained austenite grains.

IMPROVEMENT OF SCREENING FOR MANGANESE EFFICIENCY BY PRODUCING SEED WITH SIMILAR MANGANESE CONTENT IN DIFFERENT GENOTYPES AND GENETIC STOCKS

ABSTRACT Genetic improvement of manganese efficiency of crops demands a precise bioassay that avoids the confounding effect of seed manganese on the bioassay for the trait, for a proper comparison of the genotypes the seed manganese content must be similar. Variation in seed manganese can be minimized by the addition of manganese to individual seeds to be planted providing the effect of seed manganese content on early growth and development for the chosen genotype has been determined. It was hypothesized that growing the plants as mono-culms in very small pots under subclinical manganese deficiency would limit grain yield and yield attribute among genotypes, resulting in seed with less variation in manganese content across genotypes. The effect on yield and components of soil fertility ranging from University of California (UC) potting mix, fortified with Osmocote, to 100% manganese-deficient calcareous sand from Wangary, South Australia (Psamment) was determined for 20 bread wheat genotypes and breeding lines. It was observed that a mix of 70% UC and 30% Calcareous Wangary sand from South Australia in small pots minimized variation in grain yield and its components (number of tillers, number of seeds/head, weight of seed) and also lowered variation in seed manganese content among wheat genotypes. This was confirmed in pots of 70/30 UC-sand mix for five bread wheat cultivars, Worrakatta, Barunga, Schomburg, Excalibur, and Frame. The pot results from three replicates were compared with field results for the same genotypes grown at five randomly selected wheat-growing areas in South Australia: Paskeville, Geranium, Minnipa, Nunji, and Cummins. The variation in seed manganese content across genotypes was much less in pot grown seed. Aneuploid stocks (D-genome diosomic substitution lines) normally have highly variable seed size. Production of seed with similar manganese content was only feasible by growing the seed under multiple levels of soil manganese supply and after analysis selecting seeds with similar manganese content among the various manganese treatments. The effect of aneuploidy on seedling vigor, root growth, seed size and agronomic performance has been reported elsewhere. The effect on seed manganese content and the genetic analysis of micronutrient (manganese) efficiency were determined in the current study.

Rocks with negative cerium anomalies, dredged from Shatsky Rise.

Some of basaltic rocks dredged from Shatsky Rise have large negative cerium anomalies. Also these samples have a wide variation in manganese content, and there appears to be some relationship between the extent of cerium anomaly and the manganese content. These observations may be of much significance for discussions of manganese nodule genesis.

A absorção do manganês pela cana de açúcar, Co 419, em função da idade

In this paper the authors have studied the manganese absorption by the sugar cane plant, variety Co 419, in samples cut monthly, from the 6th to 15th month of life in the climate prevailing at Piracicaba, State of Sao Paulo, Brazil. From October to February (6 th to 10 th month of the plant life), which coincided with the rainy season, the manganese content was higher in the stalk than in the leaves, for both treatments, fertilized and unfertilized. There was a sharp decrease in manganese content in the stalks, after February, in both reatments. In the leaves there was little variation in manganese content throughout the plant tissue. The stalks from the unfertilized plots had a larger variation in manganese content, specially from the 6 th to the 10 th month. In the leaves of the sugar cane from the unfertilized plots, the manganese content varied from 116 to 220 ppm, whereas in the fertilized treatments thire was a variation from 150 to 220 ppm. From these results, althoug not being a foliar analyses, and considering the easy availability of manganese in acid soils, there must be enough of it, if we consider 40 ppm (EVANS, 1955) as a minimum for healthy plants.

Distribution of Manganese in Foods

The manganese content of 83 representative food materials is given. The concentrations range from 0.028 mg. per liter of milk to 49.9 mg. per kilo. of bran flakes. Thirty-six of the materials contained less than 1 mg., twenty-five from 1 to 5 mg., and only twenty-two more than 5 mg. per kilo. of fresh material. Arranged in descending order with respect to their manganese content, 12 classes of foods, representing 138 food materials, appear as follows: nuts; cereals and their products; dried legume seeds; green leafy vegetables; dried fruits; roots, tubers, and stalks; fresh fruits; non-leafy vegetables; animal tissue; poultry and poultry products; dairy products; and fish and sea foods. Marked variations in manganese content were found among the several members of a given group. In typical American diets cereals and their products contribute the largest proportion of the manganese intake.