Mg{sub x}Mn{sub (1-x)}(BH{sub 4}){sub 2} (x = 0-0.8), a cation solid solution in a bimetallic borohydride

Energy Technology Data Exchange (ETDEWEB)

Cerny, Radovan, E-mail: radovan.cerny@unige.ch [Laboratory of Crystallography, University of Geneva, 1211 Geneva (Switzerland); Penin, Nicolas [Laboratory of Crystallography, University of Geneva, 1211 Geneva (Switzerland); CNRS, Universite de Bordeaux 1, ICMCB, 87 Avenue du Docteur Albert Schweitzer, F-33608 Pessac Cedex (France); D' Anna, Vincenza; Hagemann, Hans [Department of Physical Chemistry, University of Geneva, 1211 Geneva (Switzerland); Durand, Etienne [CNRS, Universite de Bordeaux 1, ICMCB, 87 Avenue du Docteur Albert Schweitzer, F-33608 Pessac Cedex (France); Ruzicka, Jakub [Charles University, Faculty of Science, Department of Inorganic Chemistry, Hlavova 2030, 128 40, Prague 2 (Czech Republic)

2011-08-15

Highlights: {yields} The magnesium and manganese borohydrides form a solid solution Mg{sub x}Mn{sub (1-x)}(BH{sub 4}){sub 2} (x = 0-0.8) which conserves the trigonal structure of Mn{sub (}(BH{sub 4}){sub 2}. {yields} Coexistence of both trigonal and hexagonal borohydrides occurs within nominal composition ranging from x{sub Mg} = 0.8-0.9. {yields} The decomposition temperature of trigonal Mg{sub x}Mn{sub (1-x)}(BH{sub 4}){sub 2} (x = 0-0.8) does not vary significantly with magnesium content (433-453 K). {yields} The desorbed gas contains mostly hydrogen and 3-7.5 mol.% of diborane B{sub 2}H{sub 6}. - Abstract: A solid solution of magnesium and manganese borohydrides was studied by in situ synchrotron radiation X-ray powder diffraction and infrared spectroscopy. A combination of thermogravimetry, mass and infrared spectroscopy, and atomic emission spectroscopy were applied to clarify the thermal gas desorption of pure Mn(BH{sub 4}){sub 2} and a solid solution of composition Mg{sub 0.5}Mn{sub 0.5}(BH{sub 4}){sub 2}. Mg{sub x}Mn{sub (1-x)}(BH{sub 4}){sub 2} (x = 0-0.8) conserves the trigonal structure of Mn(BH{sub 4}){sub 2} at room temperature. Manganese is dissolved in the hexagonal structure of {alpha}-Mg(BH{sub 4}){sub 2}, with the upper solubility limit not exceeding 10 mol.% at room temperature. There exists a two-phase region of trigonal and hexagonal borohydrides within the compositional range x = 0.8-0.9 at room temperature. Infrared spectra show splitting of various vibrational modes, indicating the presence of two cations in the trigonal Mg{sub x}Mn{sub (1-x)}(BH{sub 4}){sub 2} solid solutions, as well as the appearance of a second phase, hexagonal {alpha}-Mg(BH{sub 4}){sub 2}, at higher magnesium contents. All vibrational frequencies are shifted to higher values with increasing magnesium content. The decomposition temperature of the trigonal Mg{sub x}Mn{sub (1-x)}(BH{sub 4}){sub 2} (x = 0-0.8) does not vary significantly as a function of the magnesium

The Enhancement of Mg Corrosion Resistance by Alloying Mn and Laser-Melting

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Youwen Yang

2016-03-01

Full Text Available Mg has been considered a promising biomaterial for bone implants. However, the poor corrosion resistance has become its main undesirable property. In this study, both alloying Mn and laser-melting were applied to enhance the Mg corrosion resistance. The corrosion resistance, mechanical properties, and microstructure of rapid laser-melted Mg-xMn (x = 0–3 wt % alloys were investigated. The alloys were composed of dendrite grains, and the grains size decreased with increasing Mn. Moreover, Mn could dissolve and induce the crystal lattice distortion of the Mg matrix during the solidification process. Mn ranging from 0–2 wt % dissolved completely due to rapid laser solidification. As Mn contents further increased up to 3 wt %, a small amount of Mn was left undissolved. The compressive strength of Mg-Mn alloys increased first (up to 2 wt % and then decreased with increasing Mn, while the hardness increased continuously. The refinement of grains and the increase in corrosion potential both made contributions to the enhancement of Mg corrosion resistance.

Moment mapping of body-centered-cubic Fe{sub x}Mn{sub 1−x} alloy films on MgO(001)

Energy Technology Data Exchange (ETDEWEB)

Idzerda, Y. U., E-mail: idzerda@physics.montana.edu; Bhatkar, H. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States); Arenholz, E. [Advanced Light Source, Lawrence Berkeley National Laboratories, Berkeley, California 59717 (United States)

2015-05-07

The alloy composition and elemental magnetic moments of bcc single crystal films of compositionally graded Fe{sub x}Mn{sub 1−x} films (20 nm thick films with 0.8 ≤ x ≤ 0.9) grown on MgO(001) are spatially mapped using X-ray absorption spectroscopy and magnetic circular dichroism. Electron diffraction measurements on single composition samples confirmed that the structure of Fe{sub x}Mn{sub 1−x} films remained epitaxial and in the bcc phase from 0.65 ≤ x ≤ 1, but rotated 45° with respect to the MgO(001) surface net. This is beyond the bulk bcc stability limit of x = 0.88. The Fe moment is found to gradually reduce with increasing Mn content with a very abrupt decline at x = 0.85, a slightly higher composition than observed in the bulk. Surprisingly, the Mn exhibits a very small net moment (<0.1 μ{sub B}) at all compositions, suggesting a complex Mn spin structure.

Heavy Metals (Mg, Mn, Ni and Sn contamination in Soil Samples of Ahvaz II Industrial Estate of Iran in 2013

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Soheil l Sobhanardakani

2016-04-01

Full Text Available Background & Aims of the Study: Due to the rapid industrial development in Khuzestan province of Iran during recent years, this study was performed to analyze the variation of metals concentrations (Mg, Mn, Ni, and Sn in soil samples of Ahvaz II Industrial estate during the spring season of 2013. Materials & Methods: In this experimental study, 27 topsoil samples were collected from nine stations. The intensity of the soil contamination was evaluated, using a contamination factor (Cf and geo-accumulation index (I-geo. Results:  The mean soil concentrations (in mg kg-1 (dry weight were in ranged within 870-1144 (Mg, 188-300 (Mn, 93-199 (Ni and 9-15 (Sn. The data indicated that the I-geo value for all metals falls in class ‘1’. Also the Cf value for Mg and Mn falls in class ‘0’, the Cf value for Sn falls in class ‘1’ and the Cf value for Ni falls in the classes of ‘1’ and ‘2’. The result of the Pearson correlation showed that there were significant positive associations between all metals. Conclusions: According to the results which were achieved by a cluster analysis, there were significant positive associations among all metals based on Pearson correlation coefficient, especially between Ni and Sn; also both of them with Mn. Because the Ni originates from oil sources it can be resulted that Mn and Sn originate from oil sources, too. Therefore, industrial activities and exploitation of oil reservoirs are the main cause of pollution in that area. Also, it can be concluded that, with increasing the distance from the source of pollution, the accumulation of contaminants in the soil samples decreased.

Structural, optical and magnetic characterizations of Mn-doped MgO nanoparticles

International Nuclear Information System (INIS)

Azzaza, S.; El-Hilo, M.; Narayanan, S.; Judith Vijaya, J.; Mamouni, N.; Benyoussef, A.; El Kenz, A.; Bououdina, M.

2014-01-01

Structural, optical and room temperature magnetic properties of Mn-doped MgO nanoparticles with Mn fractions (5–50 at.%), were investigated. The as-prepared pure MgO, with grain size of about 15 nm, exhibits two magnetization components, one is diamagnetic and another is superparamagnetic. After removing the diamagnetic contribution, the magnetization curve exhibits superparamagnetic behavior which may be attributed to vacancy defects. As the Mn content increases, the lattice parameter decreases, the ferromagnetism appears and the emission bands were considerably blue shifted. First principle electronic structure calculations reveal the decrease of both the gap and the Curie temperature with increasing Mn concentration. The obtained results suggest that both Mn doping and oxygen vacancies play an important role in the development of room temperature ferromagnetism. - Graphical abstract: The measured room temperature magnetization curve for the Mn doped MgO with 5 at.%, 10 at.% and 20 at.%. - Highlights: • Combination of experimental and calculation methods. • Decrease of both the gap and the Curie temperature with increasing Mn content. • Ferromagnetism in MgO originate from interactions between defects

Total Diet Study. Mg and Mn content estimation of a Market Basket of Sao Paulo state (Brazil) by Instrumental Neutron Activation

International Nuclear Information System (INIS)

Roseane Pagliaro Avegliano; Vera Akiko Maihara

2014-01-01

Total Diet Studies (TDS) have been carried out to estimate dietary intakes of the essential and toxic elements for a large-scale population over a specific period of time. In this study, the TDS was based on the evaluation of food representing a Market Basket (MB), which reflected the dietary habits of the Sao Paulo State population, corresponding to 72 % of the average food consumption for the state of Sao Paulo. In the present Total Diet Study, magnesium and manganese concentrations were determined in 30 of the most consumed food groups of a MB of Sao Paulo State, Brazil. Instrumental Neutron Activation Analysis (INAA) has been successfully used on a regularly basis in several areas of nutrition and foodstuffs. Element concentrations were determined by INAA in freeze-dried samples and ranged in mg kg -1 . Mg 41.4 (fats)-5287 (coffee) and Mn 0.12 (prime grade beef)-32.9 (coffee). The average daily Mg and Mn intake was calculated by multiplying the concentration of each element in each table-ready food group by the respective weight (g day -1 ) of the food group in the MB and adding the products from all food groups. The results of daily dietary intakes in this study were: Mg 174.8 and Mn 1.34 mg day -1 . Theses values were lower than the adequate intake (AI) proposed by the Food and Nutrition Board of the Institute of Medicine (USA National Academy) for adults. The low levels of Mg and Mn intakes presented in this TDS are probably due to the fact that MB of this study represented only 72 % of the weight of the most consumed household foods of Sao Paulo State. (author)

Pharmacokinetics of sugammadex 16 mg/kg in healthy Chinese volunteers.

Science.gov (United States)

de Kam, Pieter-Jan; Hou, Jie; Wang, Zaiqi; Lin, Wen Hong; van den Heuvel, Michiel

2015-06-01

Elimination of sugammadex occurs predominantly via the kidneys, with the majority of the drug excreted unchanged in the urine. To date, most studies with sugammadex have been performed in non-Asian populations. The objectives of this open-label study were to determine the pharmacokinetics (PK) and safety of single-dose sugammadex (16 mg/kg) in healthy Chinese adult volunteers. 12 Chinese subjects (6 male; 6 female) received intravenous sugammadex (16 mg/kg) as a 10-second bolus infusion. Blood samples were collected pre-sugammadex and at regular intervals up to 24 hours post-sugammadex for PK assessment. Safety was assessed via AEs, vital signs, electrocardiogram, and laboratory parameters. Following sugammadex 16 mg/kg infusion, peak sugammadex concentration was 197 μg/mL, clearance was 99.7 mL/min, and apparent volume of distribution at equilibrium was 10.5 L. Plasma sugammadex concentrations showed a polyexponential decline over time, with an overall geometric mean (CV%) terminal half-life of 145 minutes (17.9%) (139 minutes (17.7%) for males; 152 minutes (18.6%) for females). No influence of gender on the PK of sugammadex was observed. Three subjects experienced an adverse events (AE) (dysgeusia of mild intensity), which was considered possibly or probably related to sugammadex. There were no clinically significant changes in vital signs, electrocardiography or laboratory parameters. PK of sugammadex (16 mg/kg) was characterized in healthy Chinese subjects. Overall between-subject variability on clearance and apparent volume of distribution was ~ 10%. Sugammadex was generally well tolerated.

Influence of silver addition on the microstructure and mechanical properties of squeeze cast Mg-6Al-1Sn-0.3Mn-0.3Ti

International Nuclear Information System (INIS)

Acikgoez, Sehzat; Sevik, Hueseyin; Kurnaz, S.Can

2011-01-01

Graphical abstract: Highlights: → X-ray diffractometry reveals that the main phases are α-Mg, α-Ti, β-Mg 17 Al 12 and Al 8 Mn 5 in the base alloy. → With addition of silver, Al 81 Mn 19 phase was found. → The mechanical properties of the base alloy are improved with addition of silver. → The fracture surface of base alloy shows relatively deeper and more amount of dimples than that of alloys containing silver. - Abstract: In this study, the effect of silver (0, 0.2, 0.5, and 1 wt.%) on the microstructure and mechanical properties of a magnesium-based alloy (Mg-Al 6 wt.%-Sn 1 wt.%-Mn 0.3 wt.%-Ti 0.3 wt.%) were investigated. The alloys were produced under a controlled atmosphere by a squeeze-casting process. X-ray diffractometry revealed that the main phases are α-Mg, α-Ti, β-Mg 17 Al 12 and Al 8 Mn 5 in the all of alloys. In addition to, Al 81 Mn 19 phase was found with Ag additive. Besides, the amount of β-Mg 17 Al 12 phase was decreased with increasing the amount of Ag. The strength of the base alloy was increased by solid solution mechanism and decreasing the amount of β-Mg 17 Al 12 phase with addition of Ag. Furthermore, existence of Al 81 Mn 19 phase can be acted an important role in the increase on the mechanical properties of the alloys.

Experimental investigation and thermodynamic calculation of the Fe-Mg-Mn and Fe-Mg-Ni systems

Energy Technology Data Exchange (ETDEWEB)

Wang, Peisheng; Zhao, Jingrui; Xu, Honghui; Liu, Shuhong; Ouyang, Hongwu [Central South Univ., Hunan (China). State Key Lab. of Powder Metallurgy; Du, Yong [Central South Univ., Hunan (China). State Key Lab. of Powder Metallurgy; Harbin Institute of Technology (China). State Key Lab. of Advanced Welding Production Technology; Gang, Tie; Fen, Jicai [Harbin Institute of Technology (China). State Key Lab. of Advanced Welding Production Technology; Zhang, Lijun [Central South Univ., Hunan (China). State Key Lab. of Powder Metallurgy; Bochum Univ. (Germany). ICAMS Inst.; He, Cuiyun [Guangxi Univ. (China). College of Physical Science and Technology

2011-01-15

Based on the thermodynamic calculations extrapolated from the corresponding binary sub-systems, four decisive alloys in the Fe-Mg-Mn system and three in the Fe-Mg-Ni system were selected and prepared using a powder metallurgy method to measure the isothermal sections at 500 C in both systems. The prepared samples were annealed at 500 C, and then subjected to X-ray diffraction, optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectrometry as well as electron probe microanalysis. Taking into account the presently obtained experimental data and the experimental data available in the literature, thermodynamic modeling was performed for the above systems. It was found that a direct extrapolation from the corresponding three binary systems can well reproduce all the experimental data in the Fe-Mg-Mn system, while two thermodynamic parameters are needed in the Fe-Mg-Ni system to fit all the experimental data. The liquidus projections and reaction schemes for the Fe-Mg-Mn and Fe-Mg-Ni systems are also presented. (orig.)

Enhanced moments in bcc Co{sub 1−x}Mn{sub x} on MgO(001)

Energy Technology Data Exchange (ETDEWEB)

Snow, R.J.; Bhatkar, H. [Department of Physics, Montana State University, Bozeman, MT 59715 (United States); N' Diaye, A.T.; Arenholz, E. [Advanced Light Source, Lawrence Berkeley Nat. Labs, Berkeley, CA 94720 (United States); Idzerda, Y.U., E-mail: Idzerda@montana.edu [Department of Physics, Montana State University, Bozeman, MT 59715 (United States)

2016-12-01

A 40% enhancement of the Co magnetic moment has been found for thin films of bcc Co{sub 1−x}Mn{sub x} grown by molecular beam epitaxy on a 2 nm bcc Fe buffer layer on MgO(001). Although the bcc phase cannot be stabilized in the bulk, we confirm that it is stable as an epitaxial film in the composition range x=0–0.7. Using X-ray absorption spectroscopy and X-ray magnetic circular dichroism, we show that the Co moment is a maximum of 2.38 μ{sub B} at x=0.24, while the net Mn moment remains roughly constant until x=0.24, then drops steadily. Mn is found to align parallel with Co for all ferromagnetic concentrations, up to x=0.7, where the total moment of the film abruptly collapses to zero, most likely due to the onset of the observed structural instability. - Highlights: • Stabilization of bcc Co{sub 1−x}Mn{sub x} films in the composition range of x=0 to 0.7. • Enhancement of Co moment by 40% from pure bcc Co. • Parallel alignment of Mn moment and Co moment. • Measured the elemental moment of Co and Mn as a function of composition.

Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al-5Mg-Mn Alloys Solidified Under Near-Rapid Cooling.

Science.gov (United States)

Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

2016-01-29

Mn was an important alloying element used in Al-Mg-Mn alloys. However, it had to be limited to a low level (Al-5Mg-Mn alloy with low Fe content (Al₆(Fe,Mn) was small in size and amount. With increasing Mn content, intermetallic Al₆(Fe,Mn) increased, but in limited amount. In high-Fe-containing Al-5Mg-Mn alloys (0.5 wt % Fe), intermetallic Al₆(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al₆(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al₆(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al₆(Fe,Mn) to become the primary phase at a lower Mn content.

Effects of minor Zr and Sr on as-cast microstructure and mechanical properties of Mg-3Ce-1.2Mn-0.9Sc (wt.%) magnesium alloy

International Nuclear Information System (INIS)

Pan Fusheng; Yang Mingbo; Shen Jia; Wu Lu

2011-01-01

Research highlights: → Minor Zr and/or Sr additions can effectively refine the grains of the Mg-3Ce-1.2Mn-0.9Sc alloy. → Minor Zr and/or Sr additions can improve the tensile properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. → Minor Zr and/or Sr additions can improve the creep properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. - Abstract: The effects of minor Zr and Sr on the as-cast microstructure and mechanical properties of the Mg-3Ce-1.2Mn-0.9Sc (wt.%) alloy were investigated by using optical and electron microscopies, differential scanning calorimetry (DSC) analysis, and tensile and creep tests. The results indicate that adding minor Zr and/or Sr to the Mg-3Ce-1.2Mn-0.9Sc alloy does not cause an obvious change in the morphology and distribution of the Mg 12 Ce phase. However, the grains of the Zr and/or Sr-containing alloys are effectively refined. Among the Zr and/or Sr-containing alloys, the grains of the alloy with the addition of 0.5 wt.%Zr + 0.1 wt.%Sr are the finest, followed by the alloys with the additions of 0.5 wt.%Zr and 0.1 wt.%Sr, respectively. In addition, small additions of Zr and/or Sr can improve the tensile and creep properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. Among the Zr and/or Sr-containing alloys, the alloy with the addition of 0.5 wt.%Zr + 0.1 wt.%Sr obtains the optimum tensile and creep properties.

Microstructural evolution during friction stir welding of AlSi1MgMn alloy

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M. Janjić

2012-01-01

Full Text Available This paper provides the research of the infl uence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6 obtained through the Friction Stir Welding (FSW process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out.

Structural and magnetic properties of Mg doped YbMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Sattibabu, Bhumireddi, E-mail: bsb.satti@gmail.com [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Bhatnagar, Anil K., E-mail: anilb42@gmail.com [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Rayaprol, Sudhindra [UGC-DAE CSR, Mumbai Centre, R-5 Shed, BARC, Mumbai 400085 (India); Mohan, Dasari; Das, Dibakar; Sundararaman, Mahadevan [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Siruguri, Vasudeva [UGC-DAE CSR, Mumbai Centre, R-5 Shed, BARC, Mumbai 400085 (India)

2014-09-01

We have studied the effect of Mg doping on structure and magnetism of multiferroic YbMnO{sub 3}. Room temperature neutron diffraction studies were carried out on polycrystalline Yb{sub 1−x}Mg{sub x}MnO{sub 3} (x=0.00 and 0.05) samples to determine phase formation as well as cation distribution and structural properties such as bond length and bond angles. The structural analysis shows that with Mg substitution, there is a marginal change in a and c parameters of the hexagonal unit cell, c/a ratio remains constant for x=0 and 0.05 samples. Due to changes in bond angle and bond lengths on substituting Mg, there is a slight decrease in the distortion of MnO{sub 5} polyhedra. Magnetic measurements show that the Néel temperature (T{sub N}) increases marginally from 85 K for x=0.00 to 89 K for x=0.05 sample.

Efficacy, safety and pharmacokinetics of sugammadex 4 mg kg-1 for reversal of deep neuromuscular blockade in patients with severe renal impairment.

Science.gov (United States)

Panhuizen, I F; Gold, S J A; Buerkle, C; Snoeck, M M J; Harper, N J N; Kaspers, M J G H; van den Heuvel, M W; Hollmann, M W

2015-05-01

This study evaluated efficacy and safety of sugammadex 4 mg kg(-1) for deep neuromuscular blockade (NMB) reversal in patients with severe renal impairment (creatinine clearance [CLCR] Sugammadex 4 mg kg(-1) was administered at 1-2 post-tetanic counts for reversal of rocuronium NMB. Primary efficacy variable was time from sugammadex to recovery to train-of-four (T4/T1) ratio 0.9. Equivalence between groups was demonstrated if two-sided 95% CI for difference in recovery times was within -1 to +1 min interval. Pharmacokinetics of rocuronium and overall safety were assessed. The intent-to-treat group comprised 67 patients (renal n=35; control n=32). Median (95% CI) time from sugammadex to recovery to T4/T1 ratio 0.9 was 3.1 (2.4-4.6) and 1.9 (1.6-2.8) min for renal patients vs controls. Estimated median (95% CI) difference between groups was 1.3 (0.6-2.4) min; thus equivalence bounds were not met. One control patient experienced acceleromyography-determined NMB recurrence, possibly as a result of premature sugammadex (4 mg kg(-1)) administration, with no clinical evidence of NMB recurrence observed. Rocuronium, encapsulated by Sugammadex, was detectable in plasma at day 7 in 6 patients. Bioanalytical data for sugammadex were collected but could not be used for pharmacokinetics. Sugammadex 4 mg kg(-1) provided rapid reversal of deep rocuronium-induced NMB in renal and control patients. However, considering the prolonged sugammadex-rocuronium complex exposure in patients with severe renal impairment, current safety experience is insufficient to support recommended use of sugammadex in this population. NCT00702715. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of dietary manganese contents on 54Mn metabolism in mice

International Nuclear Information System (INIS)

Sato, I.; Matsusaka, N.; Kobayashi, H.; Nishimura, Y.

1996-01-01

Several parameters of 54 Mn metabolism were noted in mice maintained on diets with manganese contents of 80 to 8000 mg/kg. Excretion of 54 Mn was promoted as the dietary manganese contents increased. Clearance of 54 Mn from the liver, kidneys, pancreas, and spleen was markedly accelerated by feeding mice a high-manganese diet, but clearance from the muscles, femurs, and brain was relatively insensitive to the dietary manganese. Manganese concentrations in the tissue were regulated homoestatically upto the dietary manganese content of 2400 mg/kg, but marked accumulations of manganese occurred when mice were given 8000 mg/kg diet. No toxic symptoms were found up to the 2400 mg/kg diet, but consumption of the 8000 mg/kg diet was less than for other diets. These results suggest that an oral intake of excess manganese is effective for promoting the excretion of 54 Mn from a body contaminated with this isotope. (author)

Development and characterization of Mn2+-doped MgO nanoparticles by solution combustion synthesis

Science.gov (United States)

Basha, Md. Hussain; Gopal, N. O.; Rao, J. L.; Nagabhushana, H.; Nagabhushana, B. M.; Chakradhar, R. P. S.

2015-06-01

Mn doped MgO Nanoparticles have been prepared by Solution Combustion Synthesis. The synthesized sample is characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). The prepared MgO:Mn (1 mol%) nano crystals appear to be of simple cubic crystalline phase with lattice parameters a = 4.218(2) Å and cell volume = 74.98 (7) Å3. SEM micrograph of powders show highly porous, many agglomerates with irregular morphology, large voids, cracks and pores. EPR spectrum of the sample at room temperature exhibit an isotropic sextet hyperfine pattern, centered at g=1.99, characteristic if Mn2+ ions with S=I=5/2.The observed g value and the hyperfine value reveal the ionic bonding between Mn2+ and its surroundings.

Development and characterization of Mn2+-doped MgO nanoparticles by solution combustion synthesis

International Nuclear Information System (INIS)

Basha, Md. Hussain; Gopal, N. O.; Rao, J. L.; Nagabhushana, H.; Nagabhushana, B. M.; Chakradhar, R. P. S.

2015-01-01

Mn doped MgO Nanoparticles have been prepared by Solution Combustion Synthesis. The synthesized sample is characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). The prepared MgO:Mn (1 mol%) nano crystals appear to be of simple cubic crystalline phase with lattice parameters a = 4.218(2) Å and cell volume = 74.98 (7) Å 3 . SEM micrograph of powders show highly porous, many agglomerates with irregular morphology, large voids, cracks and pores. EPR spectrum of the sample at room temperature exhibit an isotropic sextet hyperfine pattern, centered at g=1.99, characteristic if Mn 2+ ions with S=I=5/2.The observed g value and the hyperfine value reveal the ionic bonding between Mn 2+ and its surroundings

Large enhancement of Blocking temperature by control of interfacial structures in Pt/NiFe/IrMn/MgO/Pt multilayers

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Xi Chen

2015-09-01

Full Text Available The Blocking temperature (TB of Pt/NiFe/IrMn/MgO/Pt multilayers was greatly enhanced from far below room temperature (RT to above RT by inserting 1 nm thick Mg layer at IrMn/MgO interface. Furthermore, the exchange bias field (Heb was increased as well by the control of interfacial structures. The evidence for a significant fraction of Mn-O bonding at IrMn/MgO interface without Mg insertion layer was provided by X-ray photoelectron spectroscopy. The bonding between Mn and O can decrease the antiferromagnetism of IrMn film, leading to lower value of TB in Pt/NiFe/IrMn/MgO/Pt multilayers. Ultrathin Mg film inserted at IrMn/MgO interface acting as an oxygen sinking layer can suppress the oxidation reactions between Mn and O and reduce the formation of Mn-O bonding greatly. The oxidation suppression results in the recovery of the antiferromagnetism of IrMn film, which can enhance TB and Heb. Furthermore, the high resolution transmission electron microscopy demonstrates that the Mg insertion layer can efficiently promote a high-quality MgO (200 texture. This study will enhance the understanding of physics in antiferromagnet-based spintronic devices.

Evolution of Mg-5Al-0.4Mn microstructure after rare earth elements addition

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A. Żydek

2011-04-01

Full Text Available Mg-5Al-0.4Mn-xRE (x = 0, 1, 2, 3 wt.% magnesium alloys were prepared successfully by casting method. The microstructure wasinvestigated by light microscopy. The influence of rare earth (RE elements on the area fraction of eutectic was analysed. The obtainedresults revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. However, whilerare earth elements were added to the Mg-Al type alloy, Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitatesincreased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased.

Photoluminescence study in solid solutions of CdMgMnTe semimagnetic semiconductors

International Nuclear Information System (INIS)

Kusraev, Yu.G.; Averkieva, G.K.

1993-01-01

Luminescence and resonant Raman scattering in quaternary solid solutions of CdMgMnTe semimagnetic semiconductors are investigated. It is shown that the intensity and position of the luminescence band, conditioned by the 4 T 1 --> 6 A 1 optical transitions in the Mn d-shell, depend on the local crystal environment. Temperature variations of the photoluminescence spectra are interpreted on the base of a model of electron excitation energy transport from Mn 2+ to different recombination centers. In the resonant Raman scattering spectrum were observed three longitudinal vibrational modes with energies near to phonon energies of corresponding binary compounds

The A1 to L10 transformation in FePt films with ternary alloying additions of Mg, V, Mn, and B

International Nuclear Information System (INIS)

Wang, B.; Barmak, K.; Klemmer, T. J.

2011-01-01

The impact of ternary additions of Mg, V, Mn, and B on the A1 [face centered cubic (fcc)] to L1 0 phase transformation has been studied. The films were cosputter deposited from elemental targets at room temperature and annealed after deposition. The films had Mg additions in the range ∼0-2.6 at.%, V additions in the range 0.7-12.2 at.%, Mn additions in the range 2.2-16.3 at.%, and B additions in the range 1.2-12.9 at.%. For all four ternary alloy systems, annealing resulted in the formation of no other phases than the L1 0 phase. Ternary additions of C than the binary FePt films with the same Pt content.

Ecological modelling of a wetland for phytoremediating Cu, Zn and Mn in a gold–copper mine site using Typha domingensis (Poales: Typhaceae near Orange, NSW, Australia

Directory of Open Access Journals (Sweden)

Subrahmanyam Sreenath

2017-12-01

Full Text Available An artificial wetland was computationally modelled using STELLA®, a graphical programming tool for an Au-Cu mine site in Central-west NSW, the aim of which was to offer a predictive analysis of a proposed wetland for Cu, Zn and Mn removal using Typha domingensis as the agent. The model considers the important factors that impact phytoremediation of Cu, Zn and Mn. Simulations were performed to optimise the area of the wetland; concentration of Cu, Zn and Mn released from mine (AMD; and flow rates of water for maximum absorption of the metals. A scenario analysis indicates that at AMD = 0.75mg/L for Cu, Zn and Mn, 12.5, 8.6, and 357.9 kg of Cu, Zn and Mn, respectively, will be assimilated by the wetland in 35 years, which would be equivalent to 61 mg of Cu/kg, 70 mg of Zn/kg and 2,886 mg of Mn/kg of T. domingensis, respectively. However, should Cu, Zn and Mn in AMD increase to 3 mg/L, then 18.6 kg of Cu and 11.8 kg of Zn, respectively, will be assimilated in 35 years, whereas no substantial increase in absorption for Mn would occur. This indicates that 91 mg of Cu, 96 mg of Zn and 2917 mg of Mn will be assimilated for every kg of T. domingensis in the wetland. The best option for Cu storage would be to construct a wetland of 50,000 m2 area (AMD = 0.367 mg/L of Cu, which would capture 14.1 kg of Cu in 43 years, eventually releasing only 3.9 kg of Cu downstream. Simulations performed for a WA of 30,000 m2 indicate that for AMD = 0.367 mg/L of Zn, the wetland captures 6.2 kg, releasing only 3.5 kg downstream after 43 years; the concentration of Zn in the leachate would be 10.2 kg, making this the most efficient wetland amongst the options considered for phytoremediating Zn. This work will help mine managers and environmental researchers in developing an effective environmental management plan by focusing on phytoremediation, with a view at extracting Cu, Zn and Mn from the contaminated sites.

Development and characterization of Mn{sup 2+}-doped MgO nanoparticles by solution combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Basha, Md. Hussain; Gopal, N. O., E-mail: nogopal@yahoo.com [Department of Physics, Vikrama Simhapuri University Post Graduate Center, Kavali-524201 (India); Rao, J. L. [Department of physics, Sri Venkateswara University, Tirupati-517502 (India); Nagabhushana, H. [Prof. C.N.R. Rao Centre for Nano Research, Tumkur University, Tumkur-572103 (India); Nagabhushana, B. M. [Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore - 560054 (India); Chakradhar, R. P. S. [CSIR- National Aerospace Laboratories, Bangalore -560017 (India)

2015-06-24

Mn doped MgO Nanoparticles have been prepared by Solution Combustion Synthesis. The synthesized sample is characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). The prepared MgO:Mn (1 mol%) nano crystals appear to be of simple cubic crystalline phase with lattice parameters a = 4.218(2) Å and cell volume = 74.98 (7) Å{sup 3}. SEM micrograph of powders show highly porous, many agglomerates with irregular morphology, large voids, cracks and pores. EPR spectrum of the sample at room temperature exhibit an isotropic sextet hyperfine pattern, centered at g=1.99, characteristic if Mn{sup 2+} ions with S=I=5/2.The observed g value and the hyperfine value reveal the ionic bonding between Mn{sup 2+} and its surroundings.

Ferromagnetism and transport in Mn and Mg co-implanted GaAs

Energy Technology Data Exchange (ETDEWEB)

Kulbachinskii, V A [Moscow State University, Low Temperature Physics Department, 119992, GSP-2, Moscow (Russian Federation); Gurin, P V [Moscow State University, Low Temperature Physics Department, 119992, GSP-2, Moscow (Russian Federation); Danilov, Yu A [Physico-Technical Research Institute, University of Nizhny Novgorod, 603950, Nizhny Novgorod (Russian Federation); Malysheva, E I [Physico-Technical Research Institute, University of Nizhny Novgorod, 603950, Nizhny Novgorod (Russian Federation); Horikoshi, Y [School of science and engineering, Waseda university, 3-4-1, Okubo, Tokyo 169-8555 (Japan); Onomitsu, K [School of science and engineering, Waseda university, 3-4-1, Okubo, Tokyo 169-8555 (Japan)

2007-03-15

We investigated the influence of Mn and Mg co-implantation accompanied by rapid thermal annealing on magnetic and galvanomagnetic properties of p-GaAs. We characterized the samples with SQUID magnetometry and magnetotransport measurements in the temperature interval 4.2 K1-x}Mn{sub x}As solid solution on galvanomagnetic properties of holes. Above this temperature, ferromagnetism survives due to the MnAs and Ga{sub 1-x}Mn{sub x} clusters. The magnetoresistance changes from colossal negative to enhanced positive with increasing temperature near T = 35 K.

Perbandingan Granisetron 0,01 mg/KgBb dengan Ondansetron 0,08 Mg/Kg.Bb Untuk Mencegah Mual Muntah Pascaoperasi Dini Mastektomi Radikal Modifikasi

Directory of Open Access Journals (Sweden)

Budi Fitriyana

2013-04-01

Full Text Available Postoperative nausea and vomiting not only cause discomfort to the patient, but also lead to electrolyte imbalance, regurgitation and aspiration, bleeding and loss of surgical sutures. Patients who experience postoperative nausea and vomiting will require further attention and treatment which of course increases the cost of medical services. Women who underwent mastectomy with accompanying decision underarm lymph nodes have a high risk of postoperative nausea and vomiting. Many anti-vomiting are given including antihistamines, butyrophenon, and dopamine receptor antagonists have been reported to have undesirable side effects including excessive sedation, hypotension, dry mouth, dysphoria, hallucinations and extrapyramidal effects. 5 HT3 receptor antagonists provide a major advancement for treatment of postoperative nausea and vomiting due to fewer side effects when compared with anti-vomiting medications before. This study will compare the two drugs 5 HT3 receptor antagonist granisetron with ondansetron in preventing postoperative nausea and vomiting modified radical mastectomy early. Conducted research on 58 patients ASA I and II modified radical mastectomy is performed under general anesthesia. Sampling was carried out using double-blind randomized controlled trial. Samples were divided into two groups by block randomization. Group G is given granisetron 0.01 gr / kg.bb and group O is given ondansetron 0.08 mg / kg.bb. Drug treatment is administered intravenously 30 minutes before the surgery ended on a complete evaluation of blood pressure, heart rate, oxygen saturation and length of surgery. Postoperative nausea and vomiting shortly after surgery assessed every hour until 6 hours after surgery (early postoperative nausea and vomiting to 4 scale (0-3. Data were analyzed by t-test, Chi-square test, Mann-Whitney test and Fisher's Exact test on Windows SPSS ver.16 The results suggest there is a tendency complaints of postoperative nausea and

Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

International Nuclear Information System (INIS)

Qin, Gaowu W.; Ren Yuping; Huang Wei; Li Song; Pei Wenli

2010-01-01

Graphical abstract: Display Omitted Research highlights: The ε-AlMn phase acts as the heterogeneous nucleus of α-Mg phase during the solidification of the AZ31 Mg alloy, not the γ-Al 8 Mn 5 phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure ε-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 o C. - Abstract: The effect of manganese on grain refinement of Al-containing AZ31 Mg alloy has been investigated by designing a series of Mn-Al alloys composed of either pure ε-AlMn, γ 2 -Al 8 Mn 5 or both of them using optical microscopy and X-ray diffraction. It is experimentally clarified that the grain refinement of the AZ31 Mg alloy is due to the existence of the ε-AlMn phase in the Mn-Al alloys, not the γ 2 -Al 8 Mn 5 phase. The grain size of AZ31 Mg alloy is about 91 μm without any addition of Mn-Al alloys, but remarkably decreases to ∼55 μm with the addition of either Mn-34 wt% Al or Mn-28 wt% Al. With a minor addition of 0.5 wt% Mn-28Al alloy, the grain size of AZ31 alloy decreases to ∼53 μm, and the Mn-28Al alloy can be active as grain refiner for holding time up to 60 min for the melt AZ31 alloy at 750 o C.

Natural and anthropogenic processes that concentrate Mn in rural and urban environments of the lower Mississippi River Delta

International Nuclear Information System (INIS)

Mielke, H.W.; Gonzales, C.R.; Powell, E.; Shah, A.; Mielke, P.W.

2002-01-01

This study evaluated natural processes and projected ethyl cyclopentadienyl manganese tricarbonyl fuel additives as sources of Mn accumulation in the environment. Data sets include fresh alluvium and sediments from the lower Mississippi River Delta and a soil metal survey of metropolitan New Orleans. The (1) railroad Mn, (2) industrial Mn, and (3) dynamic aquifer-stream transfer of Mn hypotheses were tested with the Mississippi River Delta data. Friction between Mn-rich steel wheels and rails contributes Mn (P=0.017) to the environment, supporting (1). Sediment loads of Mn were similar (P=0.77) upstream and downstream from the Louisiana industrial corridor, not supporting (2). The median Mn on the alluvium surface (59 mg/kg), in the aquifer (159 mg/kg), and in the riverbank aquifer discharge zone (513 mg/kg) support (3) as a mechanism for Mn enrichment of lay. The New Orleans soil metal survey data set shows a rural to urban increase of fourfold for Mn and three orders of magnitude for Pb. At 1999 .S. highway fuel use, 8.3 mg of Mn per L would yield 5000 metric tons of Mn annually. If 13% of Mn were emitted, 650 tons of Mn would become aerosols annually, while 87% or 4350 tons would remain in engines. The 1999 toxic release inventory for Mn shows 370 tons as total emissions compared to the potential of 390 and 260 tons from vehicles, respectively, in urban and rural areas. A precautionary lesson from the use of Pb as a fuel additive is that the use of Mn as a fuel additive would be associated with an increased risk or neonates exceeding the estimated total tolerable daily intake of .1-16.5μg Mn (especially in urban inner city environments) because neonates lack fully functional hepatic clearance for Mn

Determination of Mn, Fe, and Cu in chemically-treated wood pulps by the XRF addition method

Energy Technology Data Exchange (ETDEWEB)

Raemoe, J.; Klasila, T.; Piepponen, S. [VTT Chemical Technology (Finland); Sillanpaeae, M. [Oulu Univ. (Finland)

2001-08-01

A rapid X-ray fluorescence addition method has been developed for quantification of the technically most important metals in wood pulp matrix (Mn, Fe, and Cu). Pretreatment consisted of just two steps: first, acid was added to the sample to achieve homogeneous distribution of the metals; the pulp was then pressed lightly on to Mylar film. Total analysis time was less than 10 min. The concentration range investigated was up to 15 mg kg{sup -1} for Mn and up to 5 mg kg{sup -1} for Fe and Cu. Metal concentrations in Scandinavian pulps are not expected to exceed these amounts. The quantification limit was 2 mg kg{sup -1} for all three metals. The reproducibilities and repeatabilities were concentration-dependent and varied between 3 and 19% and between 1 and 17%, respectively. The squares of the linear correlation coefficients between measured intensity and added metal concentration were 0.994, 0.950, and 0.932 for Mn, Fe, and Cu, respectively. (orig.)

Co-hydrothermal synthesis of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C nano-hybrid cathode material with enhanced electrochemical performance for lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, Jun; Luo, Shaohua; Chang, Longjiao; Hao, Aimin; Wang, Zhiyuan; Liu, Yanguo; Xu, Qian; Wang, Qing; Zhang, Yahui

2017-01-01

Highlights: • A co-hydrothermal approach to synthesize LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material in water/PEG system is present. • The Mn_1_-_xMg_xPO_4 precursor is prepared by precipitation reaction. • Co-modified with Mg"2"+ doping and LiAlO_2 compositing strategies play an important role in improving the electronic conductivity and facilitating the diffusion of lithium ion. • LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material exhibits a high specific discharge capacity of 151.8 mAh/g at 0.05C. - Abstract: LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C is synthesized by a co-hydrothermal method in water/PEG system using Li_2CO_3, AAO and Mn_1_-_xMg_xPO_4 as raw material. The electronic structure and micromorphology of multi-component compound LiMn_1_-_xMg_xPO_4/C (x = 0, 1/24, 1/12, 1/6) and nano-hybrid LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C cathode materials are studied by first-principles calculation and experimental research including XRD, SEM, TEM. The calculated band gap of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4/C is 2.296 eV, which is lower than other percentages Mg"2"+ doping samples. Electrochemical tests exhibit LiMn_2_3_/_2_4Mg_1_/_2_4PO_4/C has better cycling performance and rate capability than other contents Mg"2"+ doping samples with the discharge capacity of 143.5 mAh/g, 141.5 mAh/g, 139.2 mAh/g and 136.3 mAh/g at 0.05C, 0.1C, 0.5C and 1C in order. After compositing and preparation of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material by co-hydrothermal route, the initial discharge capacity reaches up to 151.8 mAh/g, which suggests that co-modified with Mg"2"+ doping and LiAlO_2 compositing material can improve the electronic conductivity of LiMnPO_4/C by facilitating the lithium ion diffusion rate in the interior of the materials.

Grain refining mechanism of Al-containing Mg alloys with the addition of Mn-Al alloys

Energy Technology Data Exchange (ETDEWEB)

Qin, Gaowu W., E-mail: qingw@smm.neu.edu.c [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Wenhu Road 3-11, Heping District, Shenyang 110004, Liaoning Province (China); Ren Yuping; Huang Wei; Li Song; Pei Wenli [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Wenhu Road 3-11, Heping District, Shenyang 110004, Liaoning Province (China)

2010-10-08

Graphical abstract: Display Omitted Research highlights: The {epsilon}-AlMn phase acts as the heterogeneous nucleus of {alpha}-Mg phase during the solidification of the AZ31 Mg alloy, not the {gamma}-Al{sub 8}Mn{sub 5} phase. The grain refinement effect is very clear with the addition of only 0.5 wt% Mn-28Al alloy (pure {epsilon}-AlMn). The grain refinement does not deteriorate up to the holding time of 60 min at 740 {sup o}C. - Abstract: The effect of manganese on grain refinement of Al-containing AZ31 Mg alloy has been investigated by designing a series of Mn-Al alloys composed of either pure {epsilon}-AlMn, {gamma}{sub 2}-Al{sub 8}Mn{sub 5} or both of them using optical microscopy and X-ray diffraction. It is experimentally clarified that the grain refinement of the AZ31 Mg alloy is due to the existence of the {epsilon}-AlMn phase in the Mn-Al alloys, not the {gamma}{sub 2}-Al{sub 8}Mn{sub 5} phase. The grain size of AZ31 Mg alloy is about 91 {mu}m without any addition of Mn-Al alloys, but remarkably decreases to {approx}55 {mu}m with the addition of either Mn-34 wt% Al or Mn-28 wt% Al. With a minor addition of 0.5 wt% Mn-28Al alloy, the grain size of AZ31 alloy decreases to {approx}53 {mu}m, and the Mn-28Al alloy can be active as grain refiner for holding time up to 60 min for the melt AZ31 alloy at 750 {sup o}C.

Effect of minor Er and Zr on microstructure and mechanical properties of Al-Mg-Mn alloy (5083) welded joints

Energy Technology Data Exchange (ETDEWEB)

Dongxia, Yang, E-mail: yangdongxia116@emails.bjut.edu.cn [Department of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Xiaoyan, Li; Dingyong, He; Hui, Huang [Department of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China)

2013-01-20

Samples of Al-Mg-Mn and Al-Mg-Mn-Er-Zr alloys were welded using the method of laser welding. The influence of Er and Zr on microstructure, microhardness and mechanical properties of the Al-Mg-Mn alloy welded joints were investigated. It has been found that addition of Er and Zr refines the grain size in the fusion zone, due to the formation of primary Al{sub 3}Zr and Al{sub 3}Er. Fine equiaxed grains are dominated near the fusion boundary of the Al-Mg-Mn-Er-Zr alloy joint, which is contrary with the columnar crystal in the Al-Mg-Mn alloy joint. Microhardness of the center of the fusion zone rises from 74HV{sub 0.1} to 84HV{sub 0.1} owing to the grain refinement by Er and Zr. The tensile test result shows that the ultimate tensile strength and yield strength are improved by adding Er and Zr. The main reason for this is related to grain refining strengthening.

Co-hydrothermal synthesis of LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}·LiAlO{sub 2}/C nano-hybrid cathode material with enhanced electrochemical performance for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jun [School of Metallurgy, Northeastern University, Shenyang, 110004 (China); Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province, Qinhuangdao, 066004 (China); Luo, Shaohua, E-mail: tianyanglsh@163.com [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004 (China); Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province, Qinhuangdao, 066004 (China); School of Materials Science and Engineering, Northeastern University, Shenyang, 110004 (China); Chang, Longjiao [School of New Energy, Bohai University, Jinzhou, 121013 (China); Hao, Aimin; Wang, Zhiyuan; Liu, Yanguo [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004 (China); Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province, Qinhuangdao, 066004 (China); School of Materials Science and Engineering, Northeastern University, Shenyang, 110004 (China); Xu, Qian [School of Materials Science and Engineering, Shanghai University, Shanghai, 200072 (China); Wang, Qing; Zhang, Yahui [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004 (China); Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province, Qinhuangdao, 066004 (China); School of Materials Science and Engineering, Northeastern University, Shenyang, 110004 (China)

2017-02-01

Highlights: • A co-hydrothermal approach to synthesize LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}·LiAlO{sub 2}/C composite material in water/PEG system is present. • The Mn{sub 1-x}Mg{sub x}PO{sub 4} precursor is prepared by precipitation reaction. • Co-modified with Mg{sup 2+} doping and LiAlO{sub 2} compositing strategies play an important role in improving the electronic conductivity and facilitating the diffusion of lithium ion. • LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}·LiAlO{sub 2}/C composite material exhibits a high specific discharge capacity of 151.8 mAh/g at 0.05C. - Abstract: LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}·LiAlO{sub 2}/C is synthesized by a co-hydrothermal method in water/PEG system using Li{sub 2}CO{sub 3}, AAO and Mn{sub 1-x}Mg{sub x}PO{sub 4} as raw material. The electronic structure and micromorphology of multi-component compound LiMn{sub 1-x}Mg{sub x}PO{sub 4}/C (x = 0, 1/24, 1/12, 1/6) and nano-hybrid LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}·LiAlO{sub 2}/C cathode materials are studied by first-principles calculation and experimental research including XRD, SEM, TEM. The calculated band gap of LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}/C is 2.296 eV, which is lower than other percentages Mg{sup 2+} doping samples. Electrochemical tests exhibit LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}/C has better cycling performance and rate capability than other contents Mg{sup 2+} doping samples with the discharge capacity of 143.5 mAh/g, 141.5 mAh/g, 139.2 mAh/g and 136.3 mAh/g at 0.05C, 0.1C, 0.5C and 1C in order. After compositing and preparation of LiMn{sub 23/24}Mg{sub 1/24}PO{sub 4}·LiAlO{sub 2}/C composite material by co-hydrothermal route, the initial discharge capacity reaches up to 151.8 mAh/g, which suggests that co-modified with Mg{sup 2+} doping and LiAlO{sub 2} compositing material can improve the electronic conductivity of LiMnPO{sub 4}/C by facilitating the lithium ion diffusion rate in the interior of the materials.

α-MnO2 Nanowires/Graphene Composites with High Electrocatalytic Activity for Mg-Air Fuel Cell

International Nuclear Information System (INIS)

Jiang, Min; He, Hao; Huang, Chen; Liu, Bo; Yi, Wen-Jun; Chao, Zi-Sheng

2016-01-01

Highlights: • α-MnO 2 NWs/graphene was synthesized and studied in Mg-air fuel cell. • The performance of α-MnO 2 NWs/graphene is close to the Pt/C. • The ORR mechanism involves a one-step, quasi-4-electron pathway. • A large area (5 cm*5 cm) cathode was prepared and tested in a full cell. - Abstract: This paper reports the preparation of α-MnO 2 NWs/graphene composites as the cathode catalyst for magnesium-air fuel cell and its excellent electrochemistry performance. The composites are synthesized by self-assembly of α-MnO 2 nan α-MnO 2 NWs/graphene was synthesized and studied in Mg-air fuel cell. α-MnO 2 NWs/graphene was synthesized and studied in Mg-air fuel cell. owires (NWs) on the surface of graphene via a simple hydrothermal method. The α-MnO 2 NWs/graphene composites showed a higher electrochemical activity than the commercial MnO 2 . The oxygen reduction peak of the α-MnO 2 NWs/graphene composites catalyst is tested in a 0.1 M KOH solution at −0.252 V, which is more positive than the commercial MnO 2 (−0.287 V). The ORR limit current density for 28% α-MnO2 NWs/graphene composite is approximately 2.74 mA/cm 2 , which is similar to that of the 20% Pt/C(2.79 mA/cm 2 ) in the same conditions. Based on the Koutecky–Levich plot, the ORR mechanism of the composite involves a one-step, quasi-4-electron pathway. In addition, magnesium-air fuel cell with α-MnO 2 NWs/graphene as catalyst possesses higher current density (140 mA/cm 2 ) and power density (96 mW/cm 2 ) compared to the commercial MnO 2 . This study proves that the cost-effective α-MnO 2 NWs/graphene with higher power generation ability make it possible for the substitute of the noble metals catalyst in the Mg-air fuel cell.

Microstructures, mechanical and corrosion properties and biocompatibility of as extruded Mg-Mn-Zn-Nd alloys for biomedical applications.

Science.gov (United States)

Zhou, Ying-Long; Li, Yuncang; Luo, Dong-Mei; Ding, Yunfei; Hodgson, Peter

2015-04-01

Extruded Mg-1Mn-2Zn-xNd alloys (x=0.5, 1.0, 1.5 mass %) have been developed for their potential use as biomaterials. The extrusion on the alloys was performed at temperature of 623K with an extrusion ratio of 14.7 under an average extrusion speed of 4mm/s. The microstructure, mechanical property, corrosion behavior and biocompatibility of the extruded Mg-Mn-Zn-Nd alloys have been investigated in this study. The microstructure was examined using X-ray diffraction analysis and optical microscopy. The mechanical properties were determined from uniaxial tensile and compressive tests. The corrosion behavior was investigated using electrochemical measurement. The biocompatibility was evaluated using osteoblast-like SaOS2 cells. The experimental results indicate that all extruded Mg-1Mn-2Zn-xNd alloys are composed of both α phase of Mg and a compound of Mg7Zn3 with very fine microstructures, and show good ductility and much higher mechanical strength than that of cast pure Mg and natural bone. The tensile strength and elongation of the extruded alloys increase with an increase in neodymium content. Their compressive strength does not change significantly with an increase in neodymium content. The extruded alloys show good biocompatibility and much higher corrosion resistance than that of cast pure Mg. The extruded Mg-1Mn-2Zn-1.0Nd alloy shows a great potential for biomedical applications due to the combination of enhanced mechanical properties, high corrosion resistance and good biocompatibility. Copyright © 2014 Elsevier B.V. All rights reserved.

Low cycle fatigue behavior of die cast Mg-Al-Mn-Ce magnesium alloy

Directory of Open Access Journals (Sweden)

Wu Wei

2013-11-01

Full Text Available Fatigue failure is a main failure mode for magnesium and other alloys. It is beneficial for fatigue design and fatigue life improvement to investigate the low cycle fatigue behavior of magnesium alloys. In order to investigate the low cycle fatigue behavior of die cast Mg-Al-Mn-Ce magnesium alloy, the strain controlled fatigue experiments were performed at room temperature and fatigue fracture surfaces of specimens were observed with scanning election microscopy for the alloys under die-cast and aged states. Cyclic stress response curves, strain amplitude versus reversals to failure curve, total strain amplitude versus fatigue life curves and cyclic stress-strain curves of Mg-Al-Mn-Ce alloys were analyzed. The results show that the Mg-Al-Mn-Ce alloys under die-cast (F and aged (T5 states exhibit cyclic strain hardening under the applied total strain amplitudes, and aging treatment could greatly increase the cyclic stress amplitudes of die cast Mg-Al-Mn-Ce alloys. The relationships between the plastic strain amplitude, the elastic strain amplitude and reversals to failure of Mg-Al-Mn-Ce magnesium alloy under different treatment states could be described by Coffin-Manson and Basquin equations, respectively. Observations on the fatigue fracture surface of specimens reveal that the fatigue cracks initiate on the surface of specimens and propagate transgranularly.

The effect of age on Br, Ca, Cl, K, Mg, Mn, and Na mass fraction in pediatric and young adult prostate glands investigated by neutron activation analysis

International Nuclear Information System (INIS)

Zaichick, Vladimir; Zaichick, Sofia

2013-01-01

The effect of age on chemical element mass fractions in intact prostate of 50 apparently healthy 0–30 year old males was investigated by neutron activation analysis with high resolution spectrometry of short-lived radionuclides. Mean values (M±SΕΜ) for mass fraction (mg kg −1 , dry mass basis) of chemical elements before the time of puberty and in the period of puberty and post-puberty were: Br 46.0±6.7, Ca 1151±140, Cl 14572±700, K 10147±700, Mg 771±131, Mn 2.13±0.25, Na 9880±659 and Br 29.0±4.6, Ca 2049±364, Cl 11518±1121, K 13029±542, Mg 1186±134, Mn 1.74±0.16, Na 9887±716, respectively. A tendency of age-related increase in Ca, K, and Mg mass fraction and of age-related decrease in Br mass fraction was observed in period of life from 0 to 30 years. This new data indicates that of the elements studied, only the Ca, K, and Mg mass fraction in prostate tissue is an androgen-dependent parameter

Catalytic Combustion of Low Concentration Methane over Catalysts Prepared from Co/Mg-Mn Layered Double Hydroxides

Directory of Open Access Journals (Sweden)

Hongfeng Liu

2014-01-01

Full Text Available A series of Co/Mg-Mn mixed oxides were synthesized through thermal decomposition of layered double hydroxides (LDHs precursors. The resulted catalysts were then subjected for catalytic combustion of methane. Experimental results revealed that the Co4.5Mg1.5Mn2LDO catalyst possessed the best performance with the T90=485°C. After being analyzed via XRD, BET-BJH, SEM, H2-TPR, and XPS techniques, it was observed that the addition of cobalt had significantly improved the redox ability of the catalysts whilst certain amount of magnesium was essential to guarantee the catalytic activity. The presence of Mg was helpful to enhance the oxygen mobility and, meanwhile, improved the dispersion of Co and Mn oxides, preventing the surface area loss after calcination.

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil; Avaliacao dos teores de Br, Cl, K, Mg, Mn e V em mexilhoes Perna perna (Linnaeus, 1758: Mollusca Bivalvia) coletados no litoral do estado de Sao Paulo, Brasil

Energy Technology Data Exchange (ETDEWEB)

Seo, Daniele

2012-07-01

seasons of the year, beginning in spring 2008 and ending in winter 2009. The samples were cleaned, crushed, homogenized and dried by lyophilization for further analysis by INAA. The INAA procedure consisted of irradiating aliquots of the samples obtained in powder form in polyethylene envelopes in the nuclear research reactor IEA - R1 of IPEN / CNEN - SP together with synthetic standards of elements. The irradiation time in the reactor was 8 to 10 s under the thermal neutron flux of 6.6 x 1012 n cm-2 s-1. The concentrations of the elements were calculated using the comparative method. The INAA procedure was validated with respect to accuracy and precision, through the analysis of certified reference materials NIST SRM 1566b Oyster Tissue and NIST SRM 2876 Mussel Tissue. The results of these certified reference materials indicated good quality of results with respect to precision and accuracy. The ranges of concentrations (dry basis weight) of the elements obtained in mussels collected in Santos and Praia da Cocanha for the four seasons of the year were: 173.80 to 358.99 mg kg-1 for Br; 45658 {+-} 1811 to 109166 {+-} 824 mg kg{sup -1} for Cl; 7043 {+-} 856 to 12506 {+-} 675 mg kg{sup -1} for K; 2774 {+-} 211 to 5691 {+-} 717 mg kg{sup -1} for Mg; 7.01 {+-} 0.30 to 29.74 {+-} 3.32 mg kg{sup -1} for Mn and 0.77 {+-} 0.02 to 3.43 {+-} 0.28 mg kg{sup -1} for V. The seasonal and spatial variations of the concentrations of these elements were studied and the values compared to the literature. From the results obtained it can be concluded that the species of Perna perna mussels, can be used as biomonitors of marine contamination. (author)

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil; Avaliacao dos teores de Br, Cl, K, Mg, Mn e V em mexilhoes Perna perna (Linnaeus, 1758: Mollusca Bivalvia) coletados no litoral do estado de Sao Paulo, Brasil

Energy Technology Data Exchange (ETDEWEB)

Seo, Daniele

2012-07-01

was performed in all seasons of the year, beginning in spring 2008 and ending in winter 2009. The samples were cleaned, crushed, homogenized and dried by lyophilization for further analysis by INAA. The INAA procedure consisted of irradiating aliquots of the samples obtained in powder form in polyethylene envelopes in the nuclear research reactor IEA - R1 of IPEN / CNEN - SP together with synthetic standards of elements. The irradiation time in the reactor was 8 to 10 s under the thermal neutron flux of 6.6 x 1012 n cm-2 s-1. The concentrations of the elements were calculated using the comparative method. The INAA procedure was validated with respect to accuracy and precision, through the analysis of certified reference materials NIST SRM 1566b Oyster Tissue and NIST SRM 2876 Mussel Tissue. The results of these certified reference materials indicated good quality of results with respect to precision and accuracy. The ranges of concentrations (dry basis weight) of the elements obtained in mussels collected in Santos and Praia da Cocanha for the four seasons of the year were: 173.80 to 358.99 mg kg-1 for Br; 45658 {+-} 1811 to 109166 {+-} 824 mg kg{sup -1} for Cl; 7043 {+-} 856 to 12506 {+-} 675 mg kg{sup -1} for K; 2774 {+-} 211 to 5691 {+-} 717 mg kg{sup -1} for Mg; 7.01 {+-} 0.30 to 29.74 {+-} 3.32 mg kg{sup -1} for Mn and 0.77 {+-} 0.02 to 3.43 {+-} 0.28 mg kg{sup -1} for V. The seasonal and spatial variations of the concentrations of these elements were studied and the values compared to the literature. From the results obtained it can be concluded that the species of Perna perna mussels, can be used as biomonitors of marine contamination. (author)

Electrochemical properties of the ball-milled LaMg10NiMn alloy with Ni powders

International Nuclear Information System (INIS)

Wang Yi; Wang Xin; Gao Xueping; Shen Panwen

2008-01-01

The electrochemical characteristics of the ball-milled LaMg 10 NiMn alloys with Ni powders were investigated. It was found that the ball-milled LaMg 10 NiMn + 150 wt.% Ni composite exhibited higher first discharge capacity and better cycle performance. By means of the analysis of electrochemical impedance spectra (EIS), it was shown that the existence of manganese in LaMg 10 NiMn alloy increased the electrocatalytic activity due to its catalytic effect, and destabilized metal hydrides, and so reduced the hydrogen diffusion resistance. These contributed to the higher discharge capacity of the ball-milled LaMg 10 NiMn-Ni composite. According to the analytical results of X-ray diffraction (XRD), EIS and steady-state polarization (SSP) experiments, the inhibition of metal corrosion is not the main reason for the better cycle performance. The main reason is that the electrochemical reaction resistance of the ball-milled LaMg 10 NiMn-Ni composite is always lower than that of the ball-milled LaMg 10 Ni 2 -Ni composite because the former one contains manganese, which is a catalyst for the electrode reaction

Bio-corrosion characterization of Mg-Zn-X (X = Ca, Mn, Si) alloys for biomedical applications.

Science.gov (United States)

Rosalbino, F; De Negri, S; Saccone, A; Angelini, E; Delfino, S

2010-04-01

The successful applications of magnesium-based alloys as biodegradable orthopedic implants are mainly inhibited due to their high degradation rates in physiological environment. This study examines the bio-corrosion behaviour of Mg-2Zn-0.2X (X = Ca, Mn, Si) alloys in Ringer's physiological solution that simulates bodily fluids, and compares it with that of AZ91 magnesium alloy. Potentiodynamic polarization and electrochemical impedance spectroscopy results showed a better corrosion behaviour of AZ91 alloy with respect to Mg-2Zn-0.2Ca and Mg-2Zn-0.2Si alloys. On the contrary, enhanced corrosion resistance was observed for Mg-2Zn-0.2Mn alloy compared to the AZ91 one: Mg-2Zn-0.2Mn alloy exhibited a four-fold increase in the polarization resistance than AZ91 alloy after 168 h exposure to the Ringer's physiological solution. The improved corrosion behaviour of the Mg-2Zn-0.2Mn alloy with respect to the AZ91 one can be ascribed to enhanced protective properties of the Mg(OH)(2) surface layer. The present study suggests the Mg-2Zn-0.2Mn alloy as a promising candidate for its applications in degradable orthopedic implants, and is worthwhile to further investigate the in vivo corrosion behaviour as well as assessed the mechanical properties of this alloy.

Efeitos da suplementação de fitase sobre a disponibilidade aparente de Mg, Ca, Zn, Cu, Mn e Fe em alimentos vegetais para a tilápia-do-nilo Effects of phytase supplementation on apparent availability of Mg, Ca, Zn, Cu, Mn, and Fe of plant feedstuffs for nile tilapia

Directory of Open Access Journals (Sweden)

Giovani Sampaio Gonçalves

2005-12-01

Full Text Available Cem juvenis de tilápia-do-nilo (Oreochromis niloticus; PV = 100.0 ± 5.0 g foram distribuídos em 10 tanques-rede com o objetivo de avaliar o efeito da suplementação da enzima fitase (0, 1.000 e 2.000 UFA/kg sobre a disponibilidade de minerais em alguns alimentos energéticos (milho, milho extrusado, farelo de trigo, farelo de arroz e farelo de sorgo e protéicos (farelo de soja extrusado, farelo de soja, farelo de girassol, farelo de algodão e glúten de milho utilizados na alimentação de tilápia-do-nilo (Oreochromis niloticus. Para determinação dos coeficientes de disponibilidade aparente (CDA do cálcio (Ca, magnésio (Mg, zinco (Zn, cobre (Cu, ferro (Fe e manganês (Mn, foram confeccionadas 31 rações, marcadas com 0,10% de óxido de crômio III uma referência (ração purificada e 30 contendo os dez alimentos e os diferentes níveis de suplementação da enzima fitase. O CDA dos nutrientes foi calculado com base no teor de crômio da ração e das fezes. A fitase aumenta, nos vegetais, a disponibilidade do Mg, Cu, Zn e Mn, os quais apresentam tendência diferenciada, em razão do seu valor biológico e do nível de suplementação de enzima.One hundred Nile tilapia juveniles (Oreochromis niloticus; BW= 100.0 ± 5.0 g were assigned to 10 experimental cages to evaluate the effects of phytase supplementation (0, 1,000, and 2,000 FTU/kg on calcium (Ca, magnesium (Mg, zinc (Zn, copper (Cu, iron (Fe and manganese (Mn availability of ten feedstuffs: five energetic (corn, extruded corn, wheat meal, rice meal and low-tannin sorghum and five protein (extruded soybean, soybean meal, sunflower meal, cottonseed meal and corn gluten meal. As reference, an albumin and gelatin-based diet [with 0.10 % chromic oxide (III as external marker] was fed to the juveniles. Thirty-one diets (one reference and 30 based on all feedstuffs and increasing levels of phytase were formulated to determine the coefficients of apparent availability of minerals (Mg

Postoperative impairment of motor function at train-of-four ratio ≥0.9 cannot be improved by sugammadex (1 mg kg-1).

Science.gov (United States)

Baumüller, E; Schaller, S J; Chiquito Lama, Y; Frick, C G; Bauhofer, T; Eikermann, M; Fink, H; Blobner, M

2015-05-01

A train-of-four ratio (TOFR) ≥0.9 measured by quantitative neuromuscular monitoring is accepted as an indication of sufficient neuromuscular recovery for extubation, even though many postsynaptic acetylcholine receptors may still be inhibited. We investigated whether antagonism with sugammadex after spontaneous recovery to TOFR≥0.9 further improves muscle function or subjective well-being. Following recovery to TOFR≥0.9 and emergence from anaesthesia, 300 patients randomly received either sugammadex 1.0 mg kg(-1) or placebo. Fine motor function (Purdue Pegboard Test) and maximal voluntary grip strength were measured before and after surgery (before and after test drug administration). At discharge from the postanaesthesia care unit, well-being was assessed with numerical analogue scales and the Quality-of-Recovery Score 40 (QoR-40). Patients' fine motor function [6 (sd 4) vs 15 (3) pegs (30 s)(-1), Psugammadex or placebo, motor function was significantly improved in both groups but did not reach the preoperative level. There was no difference between groups at any time. Global well-being was unaffected (QoR-40: placebo, 174 vs 185; sugammadex, 175 vs 186, P>0.05). Antagonizing rocuronium at TOF≥0.9 with sugammadex 1.0 mg kg(-) (1) did not improve patients' motor function or well-being when compared with placebo. Our data support the view that TOFR≥0.9 measured by electromyography signifies sufficient recovery of neuromuscular function. The trial is registered at ClinicalTrials.gov (NCT01101139). © The Author 2014. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Synthesis, structure, magnetic, electrical and electrochemical properties of Al, Cu and Mg doped MnO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Hashem, Ahmed M., E-mail: ahmedh242@yahoo.com [National Research Centre, Inorganic Chemistry Department, Behoes St., Dokki, Cairo (Egypt); Institute for Complex Materials, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Abuzeid, Hanaa M. [National Research Centre, Inorganic Chemistry Department, Behoes St., Dokki, Cairo (Egypt); Narayanan, N. [Institute for Complex Materials, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Ehrenberg, Helmut [Institute for Complex Materials, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Materials Science, Technische Universitaet Darmstadt, Petersenstr. 23, D-64287 Darmstadt (Germany); Julien, C.M. [Universite Pierre et Marie Curie, Physicochimie des Electrolytes, Colloides et Sciences Analytiques (PECSA), 4 place Jussieu, 75005 Paris (France)

2011-10-17

Highlights: {yields} Al, Mg and Cu doped MnO{sub 2} as cathode in Li-ion batteries. {yields} Pure phase MnO{sub 2} for virgin and doped MnO{sub 2} were obtained. {yields} Doping elements improve the electrical conductivity of MnO{sub 2}. {yields} Electrochemical behaviour of MnO{sub 2} improved after doping by Al, Mg and Cu. - Abstract: Pure and doped manganese dioxides were prepared by wet-chemical method using fumaric acid and potassium permanganate as raw materials. X-ray diffraction patterns show that pure and Al, Cu and Mg doped manganese dioxides (d-MnO{sub 2}) crystallized in the cryptomelane-MnO{sub 2} structure. Thermal analysis show that, with the assistance of potassium ions inside the 2 x 2 tunnel, the presence of Al, Cu and Mg doping elements increases the thermal stability of d-MnO{sub 2}. The electrical conductivity of d-MnO{sub 2} increases in comparison with pure MnO{sub 2}, while Al-doped MnO{sub 2} exhibits the lower resistivity. As shown in the magnetic measurements, the value of the experimental effective magnetic moment of Mn ions decreases with introduction of dopants, which is attributed to the presence of a mixed valency of high-spin state Mn{sup 4+}/Mn{sup 3+}. Doped MnO{sub 2} materials show good capacity retention in comparison with virgin MnO{sub 2}. Al-doped MnO{sub 2} shows the best electrochemical results in terms of capacity retention and recharge efficiency.

Thermodynamic description of the Al-Cu-Mg-Mn-Si quinary system and its application to solidification simulation

International Nuclear Information System (INIS)

Chang, Keke; Liu, Shuhong; Zhao, Dongdong; Du, Yong; Zhou, Liangcai; Chen, Li

2011-01-01

By means of the first-principles calculations, the enthalpy of formation for the quaternary phase in the Al-Cu-Mg-Si system was computed. A set of self-consistent thermodynamic parameters for the Al-Cu-Mg-Si and Al-Cu-Mn-Si systems was then obtained using CALPHAD approach taking into account the reliable experimental data and the first-principles calculations. The thermodynamic database for the Al-Cu-Mg-Mn-Si system was developed based on the constituent binary, ternary, and quaternary systems. Comprehensive comparisons between the calculated and measured phase diagrams and invariant reactions showed that the experimental information was satisfactorily accounted for by the present thermodynamic description. The obtained database was used to describe the solidification behavior of Al alloys B319.1 (90.2Al-6Si-3.5Cu-0.3Mg, in wt.%) and B319.1 + xMn (x = 0.5-2, in wt.%) under Gulliver-Scheil non-equilibrium condition. The reliability of the present thermodynamic database was also verified by the good agreement between calculation and experiment for Gulliver-Scheil non-equilibrium solidification.

Role of nitric oxide of the median preoptic nucleus (MnPO in the alterations of salivary flow, arterial pressure and heart rate induced by injection of pilocarpine into the MnPO and intraperitoneally

Directory of Open Access Journals (Sweden)

Wilson A. Saad

2003-07-01

Full Text Available We investigated the effect of L-NAME, a nitric oxide (NO inhibitor and sodium nitroprusside (SNP, an NO-donating agent, on pilocarpine-induced alterations in salivary flow, mean arterial blood pressure (MAP and heart rate (HR in rats. Male Holtzman rats (250-300 g were implanted with a stainless steel cannula directly into the median preoptic nucleus (MnPO. Pilocarpine (10, 20, 40, 80, 160 µg injected into the MnPO induced an increase in salivary secretion (P<0.01. Pilocarpine (1, 2, 4, 8, 16 mg/kg ip also increased salivary secretion (P<0.01. Injection of L-NAME (40 µg into the MnPO prior to pilocarpine (10, 20, 40, 80, 160 µg injected into the MnPO or ip (1, 2, 4, 8, 16 mg/kg increased salivary secretion (P<0.01. SNP (30 µg injected into the MnPO or ip prior to pilocarpine attenuated salivary secretion (P<0.01. Pilocarpine (40 µg injection into the MnPO increased MAP and decreased HR (P<0.01. Pilocarpine (4 mg/kg body weight ip produced a decrease in MAP and an increase in HR (P<0.01. Injection of L-NAME (40 µg into the MnPO prior to pilocarpine potentiated the increase in MAP and reduced HR (P<0.01. SNP (30 µg injected into the MnPO prior to pilocarpine attenuated (100% the effect of pilocarpine on MAP, with no effect on HR. Administration of L-NAME (40 µg into the MnPO potentiated the effect of pilocarpine injected ip. SNP (30 µg injected into the MnPO attenuated the effect of ip pilocarpine on MAP and HR. The present study suggests that in the rat MnPO 1 NO is important for the effects of pilocarpine on salivary flow, and 2 pilocarpine interferes with blood pressure and HR (side effects of pilocarpine, that is attenuated by NO.

Interaction in the NaIn(MoO4)2 - AMoO4 (A = Mg, Mn) systems

International Nuclear Information System (INIS)

Kotova, I.Yu.; Kozhevnikova, N.M.

2001-01-01

The results of investigation into NaIn(MoO 4 ) 2 - AMoO 4 (A = Mg, Mn) quasibinary cross-sections by means of X-ray diffraction and differential thermal analysis are presented. Conducted researches revealed that compounds NaMg 3 In(MoO 4 ) and NaMn 3 In(MoO 4 ) melting incongruently at 990 Deg C and 940 Deg C accordingly were formed in the NaIn(MoO 4 ) - AMoO 4 (A = Mg, Mn) systems. The data of initiation of X-ray diffraction pattern of NaMg 3 In(MoO 4 ) 5 are presented. The temperature dependences of conductivity, dielectric permeability and tangent of dielectric losses indicative on ionic-electronic nature conductivity are determined. Activation energy of conductivity in the Mg - Mn row changes moderately - from 9.91 till 5.71 eV [ru

Effect of Si, Mn, Sn on Tensile and Corrosion Properties of Mg-4Zn-0.5Ca Alloys for Biodegradable Implant Materials

Energy Technology Data Exchange (ETDEWEB)

Cho, Dae Hyun; Nam, Ji Hoon; Lee, Byeong Woo; Park, Ji Yong; Shin, Hyun Jung; Park, Ik Min [Pusan National University, Busan (Korea, Republic of)

2015-03-15

Effect of elements Si, Mn, Sn on tensile and corrosion properties of Mg-4Zn-0.5Ca alloys were investigated. The results of tensile properties show that the yield strength, ultimate tensile strength and elongation of Mg-4Zn-0.5Ca alloy increased significantly with the addition of 0.6 wt% Mn. This is considered the grain refinement effect due to addition of Mn. However addition of 0.6 wt% Si decreased yield strength, ultimate tensile strength and elongation. The bio-corrosion behavior of Mg-4Zn-0.5Ca-X alloys were investigated using immersion tests and potentiodynamic polarization test in Hank's solution. Immersion test showed that corrosion rate of Mg-4Zn-0.5Ca-0.6Mn alloy was the lowest rate and addition of 1.0 wt% Sn accelerated corrosion rate due to micro-galvanic effect in α-Mg/CaMgSn phases interface. And corrosion potential (E{sub c}orr) of Mg-4Zn-0.5Ca-0.6Mn alloy was the most noble among Mg-4Zn-0.5Ca-X alloys.

Final report of AFRIMETS.M.M-S6: supplementary comparison of 100 mg, 100 g 500 g, 1 kg and 5 kg stainless steel mass standards

Science.gov (United States)

Mautjana, R. T.; Molefe, P. T.; Mayindu, N. F.; Armah, M. N.; Ramasawmy, V.; Albasini, G. L.; Matali, S.; Richmond, H.; Rusimbi, V.; Kiwanuka, J.; Mutale, D. M.; Mutsimba, F.

2018-01-01

This report summarizes the results of AFRIMETS.M.M-S6 mass standards comparison conducted between eleven participating laboratories/countries. Two sets of five weights with nominal values 100 mg, 100 g, 500 g, 1 kg and 5 kg were used as the traveling standards. These nominal values were decided from the needs of participating laboratories submitted to the pilot laboratory through a questionnaire and agreed upon by all participants. The traveling standards were hand carried between laboratories starting from February 2014 and were received from the last participants in October 2014. The programme was coordinated by National Metrology Institute of South Africa (NMISA), who provided the travelling standards and reference values for the comparison. The corrections to the BIPM as-maintained mass unit [5] have insignificant influence on the results of this comparison. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Concentrations in plasma, epithelial lining fluid, alveolar macrophages and bronchial mucosa after a single intravenous dose of 1.6 mg/kg of iclaprim (AR-100) in healthy men.

Science.gov (United States)

Andrews, J; Honeybourne, D; Ashby, J; Jevons, G; Fraise, A; Fry, P; Warrington, S; Hawser, S; Wise, R

2007-09-01

A validated microbiological assay was used to measure concentrations of iclaprim (AR-100) in plasma, bronchial mucosa (BM), alveolar macrophages (AM) and epithelial lining fluid (ELF) after a single 1.6 mg/kg intravenous 60 min iv infusion of iclaprim. Male volunteers were randomly allocated to three nominal sampling time intervals 1-2 h (Group A), 3-4 h (Group B) and 5.5-7.0 h (Group C) after the start of the drug infusion. Mean iclaprim concentrations in plasma, BM, AM and ELF, respectively, were for Group A 0.59 mg/L (SD 0.18), 0.51 mg/kg (SD 0.17), 24.51 mg/L (SD 21.22) and 12.61 mg/L (SD 7.33); Group B 0.24 mg/L (SD 0.05), 0.35 mg/kg (SD 0.17), 7.16 mg/L (SD 1.91) and 6.38 mg/L (SD 5.17); and Group C 0.14 mg/L (SD 0.05), no detectable level in BM, 5.28 mg/L (SD 2.30) and 2.66 mg/L (SD 2.08). Iclaprim concentrations in ELF and AM exceeded the MIC(90) for penicillin-susceptible Streptococcus pneumoniae (MIC90 0.06 mg/L), penicillin-intermediate S. pneumoniae (MIC90 2 mg/L), penicillin-resistant S. pneumoniae (MIC90 4 mg/L) for 7, 7 and 4 h, respectively, and Chlamydia pneumoniae (MIC90 0.5 mg/L) for 7 h. Mean iclaprim concentrations in ELF exceeded the MIC90 for Haemophilus influenzae (MIC90 4 mg/L) and Moraxella catarrhalis (MIC90 8 mg/L) for up to 4 and 2 h, respectively; in AM the MIC90 was exceeded for up to 7 h. Furthermore, the MIC90 for methicillin-resistant Staphylococcus aureus of 0.12 mg/L was exceeded at all sites for up to 7 h. These data suggest that iclaprim reaches lung concentrations that should be effective in the treatment of community-acquired pneumonia.

Emission spectra of phosphor MgSO4 doped with Dy and Mn

International Nuclear Information System (INIS)

Zhang Chunxiang; Chen Lixin; Tang Qiang; Luo Daling; Qiu Zhiren

2001-01-01

Emission spectra of phosphor MgSO 4 doped with Dy and Dy/Mn were measured with an optical multichannel analyzer and a linear heating system whose temperature was controlled by a microcomputer. The emission spectrum bands at 480 nm and 580 nm of phosphor MgSO 4 doped with Dy were observed in the three dimensional (3D) glow curves. Compared with the 3D spectrum of CaSO 4 :Dy and the spectrum bands of MgSO 4 :Dy shows the same wavelengths which resulted from the quantum transitions among the energy levels of Dy 3 '+ ions. The intensities of the glow peaks in both spectrum bands (480 nm and 580 nm) of phosphor MgSO 4 doped with Dy/Mn were dramatically reduced except the 380 degree C glow peak

Comparative kinetic studies of Mn2+-activated and fructose-1,6-P-modified Mg2+-activated pyruvate kinase from Concholepas concholepas.

Science.gov (United States)

Carvajal, N; González, R; Morán, A; Oyarce, A M

1985-01-01

Initial velocity and product inhibition studies of Mn2+-activated and FDP-modified Mg2+-activated pyruvate kinase from Concholepas concholepas, were performed. Evidence is presented to show that the Mn2+-enzyme catalyzes an ordered sequential mechanism, with ADP being the first substrate and pyruvate the last product. The results presented are consistent with a random combination of reactants with the FDP-modified Mg2+-activated enzyme and the formation of the dead-end complexes enzyme ADP-ATP and enzyme-PEP-ATP.

Producing a particle-reinforced AlCuMgMn alloy by means of mechanical alloying; Herstellung einer partikelverstaerkten AlCuMgMn-Legierung durch mechanisches Legieren

Energy Technology Data Exchange (ETDEWEB)

Nestler, D.; Wielage, B. [TU Chemnitz, Institut fuer Werkstoffwissenschaft und Werkstofftechnik (Germany); Siebeck, S.

2012-07-15

High-energy ball milling (HEM) with subsequent consolidation is a suitable method to produce particle-reinforced aluminium materials. The task of HEM is to distribute the reinforcement particles as homogeneously as possible. A further application of HEM is mechanical alloying (MA). This paper deals with the combination of both applications. Pure metallic powders (Al, Cu, Mg, Mn) were milled together with SiC particles up to 10 h. The composition of the metallic powder corresponds to that of the alloy AA2017 (3.9% Cu, 0.7% Mg, 0.6% Mn). In previous experiments [1], this alloy was used in the form of atomized powder. The changes in microstructure during the formation of the composite powder have been studied by light microscopy, SEM, EDXS and XRD. The results show that the production of composite powders in a single step is possible. This not only allows the economical production of such powders, but also facilitates the use of alloy compositions that are not producible via the melting route, or only producible with difficulty via the melting route. It's possible to produce tailor-made-alloys. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Accumulation of Heavy Metals in Ricinus communis L. from Mn Contaminated Area

Directory of Open Access Journals (Sweden)

YI Xin-yu

2014-02-01

Full Text Available Xiangbi No. 1 and Zibi No. 7 were planted in the Mn contaminated soils to explore its potential of ecological remediation and ener-gy utilization in the areas of Mn contaminated site. The major nutrient elements and the concentrations of heavy metals(Mn, Pb, Zn, Cu and Cr in different parts(root, branch and leaf and topsoil samples were detected after entering into the period of reproductive growth.The results showed that the average content of Mn was as high as 7 884.96 mg·kg-1,which exceeded 6.5 times of national soil environmental quality standard(level 2.The mean level of Mn in tissues of Xiangbi No. 1 was found to be in the sequence of root>leaf>branch,whereas,the mean level of Mn in different parts of Zibi No. 7 was found to be in the order of leaf>fruit>branchroot respectively. The average concentration of Mn in the leaf reached the peak value(765.43 mg·kg-1,which was higher than Xiangbi No.1 about 79.53%.The leaf/root ratios of Pb, Cu, Cr contents in Zibi No. 7 were higher than those of Xiangbi No. 1 samples.The accumulation and translocation in plants was affect-ed by different heavy metal elements in soils.The results demonstrated that Zibi No. 7 had a better uptake and translocation capacity of Mn,Pb,Cu and Cr, meanwhile,plants of two species had differences in accumulation and translocation ability and were proved to possess good Mn-tolerance ability for remediation of heavy metal contaminated soils.

TL and OSL properties of Mn2+-doped MgGa2O4 phosphor

Science.gov (United States)

Luchechko, A.; Zhydachevskyy, Ya; Maraba, D.; Bulur, E.; Ubizskii, S.; Kravets, O.

2018-04-01

The oxide MgGa2O4 spinel ceramics doped with Mn2+ ions was synthesized by a solid-state reaction at 1200 °C in air. The activator concentration was equal 0.05 mol% of MnO. Phase purity of the synthesized samples was analyzed by X-ray diffraction technique. This spinel ceramics show efficient green emission in the range from 470 to 550 nm with a maximum at about 505 nm under UV or X-ray excitations, which is due to Mn2+ ions. MgGa2O4: Mn2+ exhibits intense thermoluminescence (TL) and optically stimulated luminescence (OSL) after influence of ionizing radiation. Are complex nature of the TL glow curves is associated with a significant number of structural defects that are responsible for the formation of shallow and deep electron traps. In this work, time-resolved OSL characteristics of the samples exposed to beta particles are reported for the first time. A light from green LED was used for optical stimulation. Obtained TL and OSL results suggest MgGa2O4:Mn2+ as perspective material for further research and possible application in radiation dosimetry.

Enhancement of Mechanical Properties of Extruded Mg-9Al-1Zn-1MM-0.7CaO-0.3Mn Alloy Through Pre-aging Treatment

Science.gov (United States)

Jeong, Seok Hoan; Kim, Yong Joo; Kong, Kyung Ho; Cho, Tae Hee; Kim, Young Kyun; Lim, Hyun Kyu; Kim, Won Tae; Kim, Do Hyang

2018-03-01

The effect of pre-aging treatment before extrusion has been investigated in Mg-9.0Al-1.0Zn-1MM-0.7CaO-0.3Mn alloy. The as-cast microstructure consists of α-Mg dendrite with secondary solidification phase particles, (Mg, Al)2Ca, β-Mg17Al12 and Al11RE3 at the inter-dendritic region. After extrusion, β-Mg17Al12 precipitates are present, but higher density and more homogeneous distribution in pre-aged alloy. In addition, μm-scale banded bulk β-Mg17Al12 particles are generated during extrusion. Al11RE3 particles are broken into small particles, and are aligned along the extrusion direction. (Mg, Al)2Ca particles are only slightly elongated along the extrusion direction, providing stronger particle stimulated nucleation (PSN) effect by severe deformation during extrusion. The mechanical properties can be significantly enhanced by introducing pre-aging treatment, i.e. β-Mg17Al12 precipitates provide grain refining and strengthening effects and (Mg, Al)2Ca particles provide PSN effect.

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil

International Nuclear Information System (INIS)

Seo, Daniele

2012-01-01

were cleaned, crushed, homogenized and dried by lyophilization for further analysis by INAA. The INAA procedure consisted of irradiating aliquots of the samples obtained in powder form in polyethylene envelopes in the nuclear research reactor IEA - R1 of IPEN / CNEN - SP together with synthetic standards of elements. The irradiation time in the reactor was 8 to 10 s under the thermal neutron flux of 6.6 x 1012 n cm-2 s-1. The concentrations of the elements were calculated using the comparative method. The INAA procedure was validated with respect to accuracy and precision, through the analysis of certified reference materials NIST SRM 1566b Oyster Tissue and NIST SRM 2876 Mussel Tissue. The results of these certified reference materials indicated good quality of results with respect to precision and accuracy. The ranges of concentrations (dry basis weight) of the elements obtained in mussels collected in Santos and Praia da Cocanha for the four seasons of the year were: 173.80 to 358.99 mg kg-1 for Br; 45658 ± 1811 to 109166 ± 824 mg kg -1 for Cl; 7043 ± 856 to 12506 ± 675 mg kg -1 for K; 2774 ± 211 to 5691 ± 717 mg kg -1 for Mg; 7.01 ± 0.30 to 29.74 ± 3.32 mg kg -1 for Mn and 0.77 ± 0.02 to 3.43 ± 0.28 mg kg -1 for V. The seasonal and spatial variations of the concentrations of these elements were studied and the values compared to the literature. From the results obtained it can be concluded that the species of Perna perna mussels, can be used as biomonitors of marine contamination. (author)

Influence of oak planting on microelement composition (on example of Mn) of ordinary chernozem

OpenAIRE

Y. O. Tagunova

2011-01-01

Changes of Mn content in the ordinary chernozem of the forb-fescue-stipa steppeunder the influence of oak afforestation within the Prisamar’ya Dniprovske region were studied. The increase of the Mn content in the soil under the artificial oak plantation was noted. The average gross content of Mn in the root layer of the chernozem improved by forest was 541.2 mg/kg and 139.2 mg/kg in the ordinary chernozem. Average content of potentially available metal (mobile forms) in the root layer is 0.5 ...

Optical features of C, N, Mn implanted MgO films

International Nuclear Information System (INIS)

Dorosinets, V.A.; Dobrinets, I.A.; Wieck, A.

2013-01-01

Optical absorption and Raman spectra investigations of C/ N/ Mn implanted MgO films have been investigated. The spectra reveal a surface modification and a dependence of the defect formation mechanism on the ion type and the annealing regime. (authors)

Origin of the 20-electron structure of Mg3 MnH7 : Density functional calculations

Science.gov (United States)

Gupta, M.; Singh, D. J.; Gupta, R.

2005-03-01

The electronic structure and stability of the 20-electron complex hydride, Mg3MnH7 is studied using density functional calculations. The heat of formation is larger in magnitude than that of MgH2 . The deviation from the 18-electron rule is explained by the predominantly ionic character of the band structure and a large crystal-field splitting of the Mn d bands. In particular, each H provides one deep band accomodating two electrons, while the Mn t2g bands hold an additional six electrons per formula unit.

Simultaneous stabilization/solidification of Mn2+ and NH4+-N from electrolytic manganese residue using MgO and different phosphate resource.

Science.gov (United States)

Shu, Jiancheng; Wu, Haiping; Liu, Renlong; Liu, Zuohua; Li, Bing; Chen, Mengjun; Tao, Changyuan

2018-02-01

This study examined simultaneous stabilization and solidification (S/S) of Mn 2+ and NH 4 + -N from electrolytic manganese residue (EMR) using MgO and different phosphate resource. The characteristics of EMR NH 4 + -N and Mn 2+ S/S behavior, S/S mechanisms, leaching test and economic analysis, were investigated. The results show that the S/S efficiency of Mn 2+ and NH 4 + -N could reach 91.58% and 99.98%, respectively, and the pH value is 8.75 when the molar ratio of Mg:P is 3:1 and the dose of PM (MgO and Na 3 PO 4 ·12H 2 O) is 8wt%. In this process, Mn 2+ could mainly be stabilized in the forms of Mn(H 2 PO 4 ) 2 ·2H 2 O, Mn 3 (PO 4 ) 2 ·3H 2 O, Mn(OH) 2 , and MnOOH, and NH 4 + -N in the form of NH 4 MgPO 4 ·6H 2 O. Economic evaluation indicates that using PM process has a lower cost than HPM and HOM process for the S/S of Mn 2+ and NH 4 + -N from EMR at the same stabilization agent dose. Leaching test values of all the measured metals are within the permitted level for the GB8978-1996 test suggested when the dose of PM, HPM and HOM is 8wt%. Copyright © 2017 Elsevier Inc. All rights reserved.

Fabrication of Mg-X-O (X = Fe, Co, Ni, Cr, Mn, Ti, V, and Zn) barriers for magnetic tunnel junctions

Science.gov (United States)

Yakushiji, K.; Kitagawa, E.; Ochiai, T.; Kubota, H.; Shimomura, N.; Ito, J.; Yoda, H.; Yuasa, S.

2018-05-01

We fabricated magnetic tunnel junctions with a 3d-transition material(X)-doped MgO (Mg-X-O) barrier, and evaluated the effect of the doping on magnetoresistance (MR) and microstructure. Among the variations of X (X = Fe, Co, Ni, Cr, Mn, Ti, V, and Zn), X = Fe and Mn showed a high MR ratio of more than 100%, even at a low resistance-area product of 3 Ωμm2. The microstructure analysis revealed that (001) textured orientation formed for X = Fe and Mn despite substantial doping (about 10 at%). The elemental mappings indicated that Fe atoms in the Mg-Fe-O barrier were segregated at the interfaces, while Mn atoms were evenly involved in the Mg-Mn-O barrier. This suggests that MgO has high adaptability for Fe and Mn dopants in terms of high MR ratio.

A comparative study of metabolism and concentration factors of Fe, Cu, Zn, Mn, Co and Mg in Carcinus maenas and Cancer irroratus ovaries during ovogenesis

International Nuclear Information System (INIS)

Martin, J.-L.M.

1975-01-01

Fe, Cu, Zn, Mn, Co, and Mg were analysed in the ovary of Carcinus maenas and Cancer irroratus during ovogenesis. In both ovaries, the relatives rates, expressed as parts per millions as a ratio of wet and dry weight, are the following: Mg>Zn>Fe>Cu>Mn>Co, while in the hemolymph of Cancer irroratus these relative rates are the following: Mg>Cu>Zn>Fe>Mn>Co. Compared to concentrations of these metals in sea water, Mg expected, all metals in the ovary of Cancer irroratus have a concentration factor upper than 1. Compared to the concentration of metals in the hemolymph is, for Fe, Mn, and Co, the concentration factor upper than 1, and for Cu, Zn and Mg, the concentration factor lower than 1. A study of correlations was done between the concentrations of metals considered in pairs, and between the concentrations of metals and the parameters: water content and gonad index [fr

Hierarchically structured MnO2 nanowires supported on hollow Ni dendrites for high-performance supercapacitors

Science.gov (United States)

Sun, Zhipeng; Firdoz, Shaik; Ying-Xuan Yap, Esther; Li, Lan; Lu, Xianmao

2013-05-01

We report a hierarchical Ni@MnO2 structure consisting of MnO2 nanowires supported on hollow Ni dendrites for high-performance supercapacitors. The Ni@MnO2 structure, which was prepared via a facile electrodeposition method, is highly porous and appears like a forest of pine trees grown vertically on a substrate. At a MnO2 mass loading of 0.35 mg cm-2, the Ni@MnO2 electrode demonstrated a specific capacitance of 1125 F g-1 that is close to the theoretical value. In addition, a remarkable high-rate performance (766 F g-1 at a discharge current density of 100 A g-1) was achieved. Electrochemical tests in a two-electrode configuration for the Ni@MnO2 structure with a high MnO2 loading of 3.6 mg cm-2 showed a low equivalent series resistance (ESR) of 1 Ω and a high specific power of 72 kW kg-1. This superior performance can be attributed to the highly porous and hierarchical structure of Ni@MnO2 that favors rapid diffusion of an electrolyte, highly conductive pathway for electron transport, and efficient material utilization.We report a hierarchical Ni@MnO2 structure consisting of MnO2 nanowires supported on hollow Ni dendrites for high-performance supercapacitors. The Ni@MnO2 structure, which was prepared via a facile electrodeposition method, is highly porous and appears like a forest of pine trees grown vertically on a substrate. At a MnO2 mass loading of 0.35 mg cm-2, the Ni@MnO2 electrode demonstrated a specific capacitance of 1125 F g-1 that is close to the theoretical value. In addition, a remarkable high-rate performance (766 F g-1 at a discharge current density of 100 A g-1) was achieved. Electrochemical tests in a two-electrode configuration for the Ni@MnO2 structure with a high MnO2 loading of 3.6 mg cm-2 showed a low equivalent series resistance (ESR) of 1 Ω and a high specific power of 72 kW kg-1. This superior performance can be attributed to the highly porous and hierarchical structure of Ni@MnO2 that favors rapid diffusion of an electrolyte, highly

Translocation of Cd and Mn from Bark to Leaves in Willows on Contaminated Sediments: Delayed Budburst Is Related to High Mn Concentrations

Directory of Open Access Journals (Sweden)

Bart Vandecasteele

2015-04-01

Full Text Available Changes in the hydrology of sediments in tidal marshes or landfills may affect the uptake of metals in the vegetation. Leaf and stem samples of Salix cinerea (grey sallow were collected during four consecutive growing seasons at six contaminated plots on a polluted dredged sediment landfill and one plot on an uncontaminated reference site. The first three contaminated plots were already emerged in the first half of the first growing season, while the other three were submerged in the first year, but became increasingly dry over the study period. Foliar and stem cutting concentrations for Cd, Zn and Mn increased on the latter three plots over the four years. Willow bark contained high concentrations of Cd, Zn and Mn. In two consecutive greenhouse experiments with willow cuttings from different origins (uncontaminated and contaminated sites and grown under different soil conditions (uncontaminated and contaminated, we observed an important translocation of Mn from bark to shoots. In a third experiment with willow cuttings collected on soils with a range of heavy metal concentrations and, thus, with a broad range of Cd (4–67 mg/kg dry matter, Zn (247–660 mg/kg dry matter and Mn (38–524 mg/kg dry matter concentrations in the bark, high Mn concentrations in the bark were found to affect the budburst of willow cuttings, while no association of delayed budburst with Cd and Zn concentrations in the bark was found. We conclude that wood and, especially, bark are not a sink for metals in living willows. The high Mn concentrations in the bark directly or indirectly caused delayed or restricted budburst of the willow cuttings.

Enhanced luminescence in SrMgAl(x)O(17±δ):yMn4+ composite phosphors.

Science.gov (United States)

Cao, Renping; Sharafudeen, Kaniyarakkal N; Qiu, Jianrong

2014-01-03

Red-emitting SrMgAlxO17±δ:yMn(4+) composite phosphors (x=10-100; y=0.05-4.0 mol%) are synthesized by solid-state reaction method in air. Addition of Al2O3 leads to the formation of two concomitant phases, i.e., SrMgAl10O17 and Al2O3 phases in the composite phosphor. Red emission from Mn(4+) ions in the composite phosphors is greatly enhanced due to multiple scattering and absorption of excitation light between SrMgAl10O17 and Al2O3 phases. SrMgAlxO17±δ:yMn(4+) composite phosphors would be a promising candidate as red phosphor in the application of a 397 nm near UV-based W-LED. Copyright © 2013 Elsevier B.V. All rights reserved.

The role of Si and Ca on new wrought Mg-Zn-Mn based alloy

International Nuclear Information System (INIS)

Ben-Hamu, G.; Eliezer, D.; Shin, K.S.

2007-01-01

The development of new wrought magnesium alloys for automotive industry has increased in recent years due to their high potential as structural materials for low density and high strength/weight ratio demands. However, the poor mechanical properties of the magnesium alloys have led to search a new kind of magnesium alloys for better strength and ductility. Magnesium alloys show strong susceptibility to localized corrosion in chlorides solutions due to their inhomogeneous microstructure. The existence of intermetallics in the microstructure of magnesium alloys might represent initiation sites for localized corrosion. This is due to the formation of galvanic couples between the intermetallics and the surrounding matrix. The main objective of this research is to investigate the corrosion behavior of new magnesium alloys; Mg-Zn-Mn-Si-Ca (ZSMX) alloys. The ZSM6X1 + YCa alloys were prepared by using hot extrusion method. AC and DC polarization tests were carried out on the extruded rods, which contain different amounts of silicon or calcium. The potential difference in air between different phases and the matrix was examined using scanning Kelvin probe force microscopy (SKPFM). The phases present in the alloys have been identified by optical microscopy and scanning electron microscopy/energy dispersive X-ray spectroscopy. Four different phases were found, i.e. intermetallics containing Si-Mn, Mg-Si, Mg-Zn and Mg-Si-Ca phase. All phases exhibited higher potential differences relative to magnesium matrix indicating a cathodic behavior. The potential difference revealed significant dependence on the chemical composition of the phases. Based on the results obtained from the scanning Kelvin probe force microscopy, the cathodic phases are effective sites for the initiation of localized corrosion in Mg-Zn-Mn-Si-Ca alloys

Synergetic effects of Sc and Zr microalloying and heat treatment on mechanical properties and exfoliation corrosion behavior of Al-Mg-Mn alloys

International Nuclear Information System (INIS)

Peng, Yongyi; Li, Shu; Deng, Ying; Zhou, Hua; Xu, Guofu; Yin, Zhimin

2016-01-01

Mechanical properties, exfoliation corrosion behavior and microstructure of Al-5.98Mg-0.47Mn and Al-6.01Mg-0.45Mn-0.25Sc-0.10Zr (wt%) alloy sheets under various homogenizing and annealing processes were investigated comparatively by tensile tests, electrochemical measurements, X-ray diffraction technique and microscopy methods. The as-cast alloys mainly consist of Fe and Mn enriched impurity phases, Mg and Mn enriched non-equilibrium aluminides and Mg 3 Al 2 phases. During homogenization treatment, solvable intermetallics firstly precipitate and then dissolve into matrix. The optimized homogenization processes for removing micro-segregation and obtaining maximum precipitation strengthening of secondary Al 3 (Sc, Zr) particles are 440 °C×8 h and 300 °C×8 h, respectively. Sc and Zr additions can make the yield strength of Al-Mg-Mn alloy increase by 21 MPa (6.9%), 120 MPa (61.2%) and 127 MPa (68.3%), when annealed at 270 °C, 300 °C and 330 °C, respectively, indicating that Orowan precipitation strengthening caused by secondary Al 3 (Sc, Zr) nano-particles is much greater than grain boundary strengthening from primary Al 3 (Sc, Zr) micro-particles. Increasing homogenization and annealing degrees and adding Sc and Zr all can decrease corrosion current density and improve exfoliation corrosion resistance. The exfoliation corrosion behavior is dominant by anodic dissolution occurring at the interface between intermetallics and α(Al) matrix. After homogenizing at 440 °C for 8 h and annealing at 300 °C for 1 h, yield strength, ultimate strength, elongation to failure and exfoliation corrosion rank are 196 MPa, 360 MPa, 20.2% and PA (slight pitting corrosion) in Al-Mg-Mn alloy, and reach to 316 MPa, 440 MPa, 17.0% and PA in Al-Mg-Mn-Sc-Zr alloy, respectively, revealing that high strength, high ductility and admirable corrosion resistance of Al-Mg-Mn alloys can be achieved by the synergetic effects of Sc and Zr microalloying and heat treatment.

Effect of Al and Mg Contents on Wettability and Reactivity of Molten Zn-Al-Mg Alloys on Steel Sheets Covered with MnO and SiO2 Layers

Science.gov (United States)

Huh, Joo-Youl; Hwang, Min-Je; Shim, Seung-Woo; Kim, Tae-Chul; Kim, Jong-Sang

2018-05-01

The reactive wetting behaviors of molten Zn-Al-Mg alloys on MnO- and amorphous (a-) SiO2-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at 460 °C and the variation in the contact angles (θc) of alloys containing 0.2-2.5 wt% Al and 0-3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the a-SiO2-covered steel exhibited nonreactive, nonwetting (θc > 90°) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the a-SiO2 layer were found to be sluggish, the wettability of Zn-Al-Mg alloys on the a-SiO2 layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and SiO2, with Zn-Al-Mg alloys could be most effectively improved by increasing the Mg content of the alloys.

Structure and magnetic properties of La2/3Sr1/3MnO3/CaMnO3 multilayers

International Nuclear Information System (INIS)

Granada, Mara; Sirena, Martin; Steren, Laura B.; Leyva, Gabriela

2004-01-01

Structural and magnetic properties of manganite-based multilayers, La 2/3 Sr 1/3 MnO 3 /CaMnO 3 , composed of ferromagnetic metals and antiferromagnetic insulator barriers are investigated in this work. Compounds of similar lattice parameters were used to build the samples, so we expect an excellent stacking of the different layers along the structure. To get a first insight of this system, the crystalline structure of a series of samples, grown on (1 0 0) SrTiO 3 and (1 0 0) MgO single-crystalline substrates, has been studied. X-ray diffraction patterns show that the structure is strongly textured in the (1 0 0) direction when grown on SrTiO 3 , regardless the composition of the bottom layer. A different result is found on the same system grown on MgO: when the buffer layer is CaMnO 3 , the structure grows in the (1 1 0) orientation while it grows in the (1 0 0) direction when the bottom layer is La 2/3 Sr 1/3 MnO 3 . Magnetic coupling of the ferromagnetic layers across the antiferromagnetic spacer has been studied with magnetization measurements

Intravenous rocuronium 0.3 mg/kg improves the conditions for tracheal intubation in cats: a randomized, placebo-controlled trial.

Science.gov (United States)

Sakai, Daniel M; Zornow, Kailee Anne; Campoy, Luis; Cable, Christina; Appel, Leslie D; Putnam, Holly J; Martin-Flores, Manuel

2018-01-01

Objectives We evaluated the use of rocuronium 0.3 mg/kg intravenously (IV) to facilitate tracheal intubation in cats anesthetized for elective ovariohysterectomy. Methods Thirty female cats were randomly allocated to receive rocuronium 0.3 mg/kg IV or an equal volume of normal saline, following induction of anesthesia with ketamine and midazolam. Thirty seconds after induction, a single investigator, unaware of treatment allocation, attempted tracheal intubation. The number of attempts and the time to complete intubation were measured. Intubating conditions were assessed as acceptable or unacceptable based on a composite score consisting of five different components. Duration of apnea after induction was measured and cases of hemoglobin desaturation (SpO 2 rocuronium 12 s [range 8-75 s]; saline 60 s [range 9-120 s]) and with fewer attempts (rocuronium 1 [range 1-2]; saline 2 [range 1-3], both P = 0.006) in cats receiving rocuronium. Unacceptable intubating conditions on the first attempt occurred in 3/15 cats with rocuronium and in 10/15 with saline ( P = 0.01). Apnea lasted 4 ± 1.6 mins with rocuronium and 2.3 ± 0.5 mins with saline ( P = 0.0007). No cases of desaturation were observed. Conclusions and relevance Rocuronium 0.3 mg/kg IV improves intubating conditions compared with saline and reduces the time and number of attempts to intubate with only a short period of apnea in cats.

Study on lithium extraction from brines based on LiMn2O4/Li1-xMn2O4 by electrochemical method

International Nuclear Information System (INIS)

Zhao, Meng-Yao; Ji, Zhi-Yong; Zhang, Yong-Guang; Guo, Zhi-Yuan; Zhao, Ying-Ying; Liu, Jie; Yuan, Jun-Sheng

2017-01-01

Highlights: •A recovery system with LiMn 2 O 4 /Li 1-x Mn 2 O 4 as electrodes was used to extract lithium. •The influence sequence of coexisting ions on lithium extraction was Mg 2+ > Na + > Ca 2+ > K + . •The values of α Li-Na , α Li-Mg and α Li-Ca were more than 300, 70 and 110, respectively. •The specific energy consumption was between 18 and 19 W h·mol −1 . -- Abstract: Lithium rechargeable batteries have been used for lithium extraction in recent years. Here, we report on a highly selective lithium recovery system that consists of a LiMn 2 O 4 positive electrode, a Li 1-x Mn 2 O 4 negative electrode and a monovalent selective anion-exchange membrane. The effect of potential, temperature and coexisting ions on lithium extraction were investigated in this paper, and the lithium recovery system was applied to extract lithium from brine and concentrated seawater. The extraction capacity of Li + reached 34.31 mg· (1 g LiMn 2 O 4 ) −1 at 1.2 V. With higher reaction rate and lower energy consumption, 25 °C (room temperature) was considered as the appropriate temperature. The system still remained high selective for Li + even in the presence of impurity ions (K + , Na + , Mg 2+ , Ca 2+ ). With simulated brine and concentrated seawater as source solutions, the concentrations of Na + , Mg 2+ and Ca 2+ were reduced more than 300, 70 and 100 times, consuming 18–19 W h per mole of lithium recovered. And the electrodes still had high separation coefficients of Li + and Me n+ (Na + , Mg 2+ , Ca 2+ ) after five cycles although a slight drop was existing.

Enhanced elevated-temperature performance of LiAl_xSi_0_._0_5Mg_0_._0_5Mn_1_._9_0_-_xO_4 (0≤x≤0.08) cathode materials for high-performance lithium-ion batteries

International Nuclear Information System (INIS)

Zhao, Hongyuan; Liu, Shanshan; Wang, Zhenwei; Cai, Yu; Tan, Ming; Liu, Xingquan

2016-01-01

In order to significantly enhance the elevated-temperature performance of LiSi_0_._0_5Mg_0_._0_5Mn_1_._9_0O_4, the LiAl_xSi_0_._0_5Mg_0_._0_5Mn_1_._9_0_-_xO_4 (0 ≤ x ≤ 0.08) samples were firstly prepared via sol-gel technique. All the obtained samples showed the intrinsic spinel structure without any other detectable impurity phases. Among these samples, the LiAl_0_._0_5Si_0_._0_5Mg_0_._0_5Mn_1_._8_5O_4 sample was found to be optimal possessing regular crystal morphology with clean surfaces and presented much better elevated-temperature cycling stability and rate capability. When carried out at 55 °C, the LiAl_0_._0_5Si_0_._0_5Mg_0_._0_5Mn_1_._8_5O_4 sample exhibited the initial discharge capacity of 123.6 mAh g"−"1 at 0.5C between 3.20 and 4.35 V. After 100 cycles, the discharge capacity could still reach up to 115.9 mAh g"−"1 with capacity retention of 93.8%, which was much higher than that of LiSi_0_._0_5Mg_0_._0_5Mn_1_._9_0O_4. At the higher discharge rate of 10C, a high discharge capacity of 82.5 mAh g"−"1 could be obtained with capacity retention of 95.6% after 50 cycles at 55 °C. By contrast, the LiSi_0_._0_5Mg_0_._0_5Mn_1_._9_0O_4 sample only exhibited 43.7 mAh g"−"1 with lower capacity retention of 61.8%. These results indicate that the introduction of appropriate amount of aluminium ions in the magnesium and silicon co-doped spinel can make up for the shortage of co-doping with magnesium and silicon ions in term of the elevated-temperature performance.

Manganese-Disrupted Interaction of Dopamine D1 and NMDAR in the Striatum to Injury Learning and Memory Ability of Mice.

Science.gov (United States)

Song, Qifan; Deng, Yu; Yang, Xinxin; Bai, Ying; Xu, Bin; Liu, Wei; Zheng, Wenxue; Wang, Can; Zhang, Meng; Xu, Zhaofa

2016-12-01

Manganese (Mn) is widely regarded as a neurotoxic heavy metal that causes learning and memory deficits. Recently, it has been proved that the striatum is related to memory and learning ability. However, no previous study focused on the effect of Mn-induced learning and memory deficits on the striatum. This study aims to investigate the probable interaction of dopamine D1 receptor (DR1) and N-methyl-D-aspartate receptor (NMDAR), two cognition-related receptors in the striatum during Mn exposure. Mice are randomly divided into four groups, including control group, 12.5 mg/kg MnCl 2 group, 25 mg/kg MnCl 2 group, and 50 mg/kg MnCl 2 group. The mice receive intraperitoneal injections of 0, 12.5, 25, and 50 mg/kg MnCl 2 once daily for 2 weeks. Then, learning and memory ability, pathological changes, expression, and interaction of DR1 and NMDAR are determined. It has been found that Mn disrupted spatial learning and memory ability of mice by Morris water maze test and the passive avoidance test. Pathological and ultrastructure were injured. Mn decreased the immunohistochemical activities, protein levels, and messenger RNA (mRNA) expression of DR1, NR1, and NR2A. Mn exposure inhibited interaction between DR1 and NMDAR in striatum by double immunofluorescent staining and co-immunoprecipitation. In conclusion, our study illustrated that Mn caused learning and memory dysfunction via injury of striatum and inhibition of interaction between DR1 and NMDAR in striatum.

Microstructure and mechanical properties of Al-Cu-Mg-Mn-Zr alloy with trace amounts of Ag

International Nuclear Information System (INIS)

Liu Xiaoyan; Pan Qinglin; Lu Congge; He Yunbin; Li Wenbin; Liang Wenjie

2009-01-01

The microstructure and mechanical properties of Al-Cu-Mg-(Ag)-Mn-Zr alloys were studied by means of tensile testing, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that small additions of Ag to Al-Cu-Mg-Mn-Zr alloy can accelerate the hardening effect of the aged alloy and reduce the time to peak-aged. The mechanical properties can be improved both at room temperature and at elevated temperatures, which is attributed to the fine and uniform plate-like Ω precipitates. Meanwhile the ductility of the studied alloys remains at relatively high level. The major strengthening phases of the Ag-free alloy are θ' and less S', while that of Al-Cu-Mg-Mn-Zr alloy containing trace amounts of Ag are Ω and less θ'.

Magnetic and transport properties of Cu1.05Cr0.89 Mg0.05O2 and Cu0.96Cr0.95 Mg0.05Mn0.04O2 films

International Nuclear Information System (INIS)

Xu Qingyu; Schmidt, Heidemarie; Zhou Shengqiang; Potzger, Kay; Helm, Manfred; Hochmuth, Holger; Lorenz, Michael; Meinecke, Christoph; Grundmann, Marius

2008-01-01

We prepared conductive, polycrystalline or amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 films on a-plane sapphire substrates by pulsed laser deposition under different O 2 partial pressure and substrate temperature. Hall measurements were performed to study the majority carrier type in these films. Polycrystalline Cu 1.05 Cr 0.89 Mg 0.05 O 2 is n-type conducting at 290 K, while in amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 the type of majority charge carriers changes from electrons to holes at around 270 K. Interestingly, the structure has little influence on the magnetic properties of the films. A clear antiferromagnetic to paramagnetic transition was observed in both polycrystalline and amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 films at 25 K. Similar electrical properties to Cu 1.05 Cr 0.89 Mg 0.05 O 2 film were observed for Cu 0.96 Cr 0.95 Mg 0.05 Mn 0.04 O 2 in dependence on the structure, while only paramagnetic without antiferromagnetic ordering was observed down to 5 K. Large negative magnetoresistance of 27% at 20 K was observed at 6 T in amorphous Cu 1.05 Cr 0.89 Mg 0.05 O 2 film

Strong sp-d exchange coupling in ZnMnTe/ZnMgTe core/shell nanowires

Energy Technology Data Exchange (ETDEWEB)

Wojnar, Piotr; Janik, Elzbieta; Szymura, Malgorzata; Zaleszczyk, Wojciech; Kret, Slawomir; Klopotowski, Lukasz; Wojciechowski, Tomasz; Baczewski, Lech T.; Wiater, Maciej; Karczewski, Grzegorz; Wojtowicz, Tomasz; Kossut, Jacek [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Suffczynski, Jan; Papierska, Joanna [Institute of Experimental Physics, Warsaw University, ul. Hoza 69, 00-681 Warsaw (Poland)

2014-07-15

In this work, our recent progress in the growth and optical studies of telluride nanowire heterostructures containing a small molar fraction of magnetic Mn-ions of only a few percent is overviewed. ZnMnTe/ZnMgTe core/shell nanowires (NWs) are grown by molecular beam epitaxy by employing the vapor-liquid-solid growth mechanism assisted with gold catalyst. The structures are studied by means of photoluminescence and microphotoluminescence in an external magnetic field. In the first step, however, an activation of the near band edge emission from ZnTe and ZnMnTe nanowires is described, which is achieved by coating the nanowires with shells made of ZnMgTe. The role of these shells is to passivate Zn(Mn)Te surface states. The incorporation of Mn ions into the crystalline lattice of ZnMnTe nanowires is manifested as a considerable blue shift of near band edge emission with increasing Mn concentration inside the nanowire cores, which reflects directly the increase of their energy gap. In an external magnetic field the near band edge emission exhibits a giant spectral redshift accompanied by an increase of the circular polarization of the emitted light. Both effect are fingerprints of giant Zeeman splitting of the band edges due to sp-d exchange interaction between the band carriers and magnetic Mn-ions. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

The magnetic Curie temperature and exchange coupling between cations in tetragonal spinel oxide Mn{sub 2.5}M{sub 0.5}O{sub 4} (M = Co, Ni, Mn, Cr, and Mg) films

Energy Technology Data Exchange (ETDEWEB)

Kuo, K.; Cheng, C. W.; Chern, G. [Physics Department and SPIN Research Center, National Chung Cheng University, Chia-Yi, Taiwan, 621 (China)

2012-04-01

Mn{sub 3}O{sub 4} is a Jahn-Taller tetragonal ferrite that has a relatively low Curie temperature (T{sub c}) of {approx}43 K due to weak coupling between the canting spins. In this study, we fabricated a series of 100-nm-thick Mn{sub 2.5}M{sub 0.5}O{sub 4} (M = Co, Ni, Mn, Cr, and Mg) films via oxygen-plasma-assisted molecular beam epitaxy and measured the structural and magnetic properties of these films. These films show single phase quality, and the c-axis lattice parameter of pure Mn{sub 3}O{sub 4} is 0.944 nm, with a c/a ratio {approx}1.16, consistent with the bulk values. The replacement of Mn by M (M = Co, Ni, Cr, and Mg) changes the lattice parameters, and the c/a ratio varies between 1.16 and 1.06 depending upon the cation distribution of the films. The magnetic Curie temperatures of these films also vary in the range of 25-66 K in that Ni and Co enhance the T{sub c} whereas Mg reduces the T{sub c} (Cr shows no effect on the T{sub c}). These changes to the T{sub c} are related to both the element electronic state and the cation distributions in these compounds. As a non-collinear spin configuration can induce electrical polarization, the present study provides a systematic way to enhance the magnetic transition temperature in tetragonal spinel ferrites.

The effect of MgO doping on the structure, magnetic and magnetotransport properties of La0.8Sr0.2MnO3 composite

International Nuclear Information System (INIS)

Aezami, A.; Eshraghi, M.; Kameli, P.; Salamati, H.

2007-01-01

Full text: The recent observation of anomalously Colossal Magnetoresistance (CMR) in the La 1-x A x MnO 3 (A = Sr, Ca, Ba or vacancies) system, has spurred renewed interest in studying these doped perovskite manganites. The properties of these materials are explained by double exchange theory of Zener and electron lattice interaction. However, the intrinsic CMR effect in the perovskite manganites is found on a magnetic field scale of several teslas and a narrow temperature range. It was found that, the presence of grain boundaries in polycrystalline samples leads to a large Low Field Magnetoresistance (LFMR) effect over a wide temperature range below the Curie temperature Tc. To achieve LFMR, different properties are considered. One of them is mixing of these CMR materials with secondary insulator phases. In this work, La 0.8 Sr 0.2 MnO 3 (LSMO) was selected as matrix material and MgO as a dopant. The La 0.8 Sr 0.2 MnO 3/x MgO samples with x= 0, 1, 2, 3, 5 and 7.5 Wt.% were prepared by Solid State Reaction method. Studies show that most part of the MgO goes into the perovskite lattice and Mg substituted Mn in LSMO and remainder segregates as a separate phase at the grain boundaries. Results also show that the value of MR decreases for all the doping levels. It seems that, due to the almost same ionic radii of Mg2+ and Mn2+, and at the higher sintering temperature, Mg2+ mostly replaced Mn3+ and weakens double exchange interaction. This speculation has been confirmed by XRD, SEM, susceptibility, resistivity and magnetoresistance analysis and measurements. (authors)

Hydrogen storage properties of LaMgNi3.6M0.4 (M = Ni, Co, Mn, Cu, Al) alloys

International Nuclear Information System (INIS)

Yang, Tai; Zhai, Tingting; Yuan, Zeming; Bu, Wengang; Xu, Sheng; Zhang, Yanghuan

2014-01-01

Highlights: • La–Mg–Ni system AB 2 -type alloys were prepared by induction melting. • Structures and lattice parameters were analysed by XRD. • Hydrogen absorption/desorption performances were studied. • Mechanisms of hydrogen absorption capacity fading were investigated. - Abstract: LaMgNi 3.6 M 0.4 (M = Ni, Co, Mn, Cu, Al) alloys were prepared through induction melting process. The phase compositions and crystal structures were characterised via X-ray diffraction (XRD). The hydrogen storage properties, including activation performance, hydrogen absorption capacity, cycle stability, alloy particle pulverisation and plateau pressure, were systemically investigated. Results show that Ni, Co, Mn and Cu substitution alloys exhibit multiphase structures comprising the main phase LaMgNi 4 and the secondary phase LaNi 5 . However, the secondary phase of the Al substitution alloy changes into LaAlNi 4 . The lattice parameters and cell volumes of the LaMgNi 4 phase follow the order Ni < Co < Al < Cu < Mn. Activation is simplified through partial substitution of Ni with Al, Cu and Co. The hydrogen absorption capacities of all of the alloys are approximately 1.7 wt.% at the first activation process; however, they rapidly decrease with increasing cycle number. In addition, the stabilities of hydriding and dehydriding cycles decrease in the order Al > Co > Ni > Cu > Mn. Hydriding processes result in numerous cracks and amorphisation of the LaMgNi 4 phase in the alloys. The p–c isotherms were determined by a Sieverts-type apparatus. Two plateaus were observed for the Ni, Co and Al substitution alloys, whereas only one plateau was found for Mn and Cu. This result was caused by the amorphisation of the LaMgNi 4 phase during the hydriding cycles. Reversible absorption and desorption of hydrogen are difficult to achieve. Substitutions of Ni with Co, Mn, Cu and Al significantly influence the reduction of hysteresis between hydriding and dehydriding

Conscious Sedation Efficacy of 0.3 and 0.5 mg/kg Oral Midazolam for Three to Six Year-Old Uncooperative Children Undergoing Dental Treatment: A Clinical Trial

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Masoud Fallahinejad Ghajari

2016-10-01

Full Text Available Objectives: Midazolam with variable dosages has been used to induce sedation in pediatric dentistry. The aim of this study was to compare the efficacy of two dosages of oral midazolam for conscious sedation of children undergoing dental treatment.Materials and Methods: In this randomized crossover double blind clinical trial, 20 healthy children (ASA I aged three to six years with negative or definitely negative Frankl behavioral rating scale were evaluated. Half of the children received 0.5mg/kg oral midazolam plus 1mg/kg hydroxyzine (A orally in the first session and 0.3mg/kg oral midazolam plus 1mg/kg hydroxyzine (B in the next session. The other half received the drugs on a reverse order. Sedation degree by Houpt sedation rating scale, heart rate and level of SpO2 were assessed at the beginning and after 15 and 30 minutes. The data were analyzed using SPSS 19 and Wilcoxon Signed Rank and McNemar’s tests.Results: The results showed that although administration of 0.5mg/kg oral midazolam was slightly superior to 0.3mg/kg oral midazolam in terms of sedation efficacy, the differences were not significant (P>0.05. The difference in treatment success was not significant either (P>0.05. Heart rate, oxygen saturation (SpO2 and respiratory rate were within the normal range and did not show a significant change (P>0.05.Conclusions: The overall success rate of the two drug combinations namely 0.5mg/kg oral midazolam plus hydroxyzine and 0.3mg/kg oral midazolam plus hydroxyzine was not significantly different for management of pediatric patients.Keywords: Conscious Sedation; Pediatric Dentistry; Midazolam; Hydroxyzine

Mechanical properties of the Mg-14Ti-1Al-0.9Mn (%Wt) synthesized by physical vapour

International Nuclear Information System (INIS)

Garces, G.; Cristina, M. C.; Torralba, M.; Adeva, P.

2001-01-01

The mechanical properties of the alloy Mg-14% Ti-1% Al-0.9 Mn obtained by PVD techniques have been evaluated up to 300 degree centigree. The alloy presents a columnar grain microstructure, typical of the zone 2 of the structure zone model of MD, where surface diffusion takes place. The alloy tested in compression at room temperature presented a high yield stress, 360 MPa. This resistance to the plastic deformation is principally due to a solid solution hardening and small grain size. The yield stress decrease with the compression temperature. However, the alloy showed low fracture resistance, especially at room temperature. The presence of pores at the grain boundaries, results in the crack formation, running fast along the grain boundary. (Author) 13 refs

Oxygen Storage Capacity and Oxygen Mobility of Co-Mn-Mg-Al Mixed Oxides and Their Relation in the VOC Oxidation Reaction

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María Haidy Castaño

2015-05-01

Full Text Available Co-Mn-Mg-Al oxides were synthesized using auto-combustion and co-precipitation techniques. Constant ratios were maintained with (Co + Mn + Mg/Al equal to 3.0, (Co + Mn/Mg equal to 1.0 and Co/Mn equal to 0.5. The chemical and structural composition, redox properties, oxygen storage capacity and oxygen mobility were analyzed using X-ray fluorescence (XRF, X-ray diffraction (XRD, Raman spectroscopy, scanning electron microscopy (SEM, temperature-programmed reduction of hydrogen (H2-TPR, oxygen storage capacity (OSC, oxygen storage complete capacity (OSCC and isotopic exchange, respectively. The catalytic behavior of the oxides was evaluated in the total oxidation of a mixture of 250 ppm toluene and 250 ppm 2-propanol. The synthesis methodology affected the crystallite size, redox properties, OSC and oxide oxygen mobility, which determined the catalytic behavior. The co-precipitation method got the most active oxide in the oxidation of the volatile organic compound (VOC mixture because of the improved mobility of oxygen and ability to favor redox processes in the material structure.

Simplified sample treatment for the determination of total concentrations and chemical fractionation forms of Ca, Fe, Mg and Mn in soluble coffees.

Science.gov (United States)

Pohl, Pawel; Stelmach, Ewelina; Szymczycha-Madeja, Anna

2014-11-15

A simpler, and faster than wet digestion, sample treatment was proposed prior to determination of total concentrations for selected macro- (Ca, Mg) and microelements (Fe, Mn) in soluble coffees by flame atomic absorption spectrometry. Samples were dissolved in water and acidified with HNO3. Precision was in the range 1-4% and accuracy was better than 2.5%. The method was used in analysis of 18 soluble coffees available on the Polish market. Chemical fractionation patterns for Ca, Fe, Mg and Mn in soluble coffees, as consumed, using a two-column solid-phase extraction method, determined Ca, Mg and Mn were present predominantly as cations (80-93% of total content). This suggests these elements are likely to be highly bioaccessible. Copyright © 2014 Elsevier Ltd. All rights reserved.

Diagnose nutricional de cafeeiros da região do Alto Jequitinhonha (MG: normas dris e faixas críticas de nutrientes Nutritional diagnosis of coffee plantations in the Upper Jequitinhonha Valley, Minas Gerais State, Brazil: dris norms and critical nutrient ranges

Directory of Open Access Journals (Sweden)

Múcio Mágno de Melo Farnezi

2009-08-01

Full Text Available As normas do Sistema Integrado de Diagnose e Recomendação (DRIS ainda não foram estabelecidas para a cultura do café do Alto Jequitinhonha, MG, o que impede que o DRIS seja aplicado nos cafeeiros da região. A diagnose foliar, mediante o uso do DRIS e de faixas críticas de referência, destaca-se entre as ferramentas potenciais que permitem usar eficientemente os fertilizantes. Desse modo, este trabalho objetiva estabelecer as normas DRIS, bem como estimar os valores das faixas críticas dos nutrientes de referência para a diagnose nutricional de cafeeiros da região do Alto Jequitinhonha, por meio do DRIS. Determinaram-se os teores foliares de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn em 52 lavouras cafeeiras, em duas safras (2005 e 2006. Foram selecionadas, para estabelecer as normas DRIS, 23 lavouras em cada safra com produtividade maior e igual a 30 sacas de grãos de café por hectare. As faixas críticas obtidas do DRIS, determinando-se a frequência com que o teor de cada nutriente das lavouras nas duas safras foi deficiente, adequado ou excessivo em relação aos padrões mencionados e teores considerados adequados pela literatura. As normas DRIS foram estabelecidas para cafeeiros da região do Alto Jequitinhonha e utilizadas para propor faixas críticas adequadas. Para isso, foram estabelecidos os valores para N (2,25-2,79 dag kg-1, P (0,18-0,22 dag kg-1, K (1,72-2,10 dag kg-1, Ca (1,26-1,51 dag kg-1, Mg (0,29-0,35 dag kg-1, S (0,13-0,32 dag kg-1, B (83,8-96,3 mg kg-1, Cu (5,7-9,3 mg kg-1, Fe (67,5-116,2 mg kg-1, Mn (219-422 mg kg-1 e Zn (17,4-30,0 mg kg-1, e faixas críticas adequadas para diagnose nutricional de cafeeiros da região do Alto Jequitinhonha, no Estado de Minas Gerais. Os cafezais da região em desequilíbrio apresentaram deficiência em P, K, S, B, Cu, Mn e Zn e excesso de Ca, Mg e Fe.In the Diagnosis and Recommendation Integrated System (DRIS, norms for coffee in the Upper Jequitinhonha Valley, Minas Gerais, Brazil

Determination of the Cl, Mg, Mn and Na, in samples of Tradescantia pallida

International Nuclear Information System (INIS)

Rossi, Joao Guilherme G.A.; Saiki, Mitiko

2009-01-01

The growing number of industries and automotive vehicles are causing the increase of the air pollution. Less expensive methodologies are been studying for the evaluation of these pollution levels. This work evaluates the concentrations of Cl, Mg, Mn and Na, present in the leaves of Tradescantia pallida viewing validation of the specie for use in the bio monitoring of the air pollution. Those leaves were collected and analysed using the short irradiation of the neutron activation analysis technique. The certified reference material INCT-MPH-2 Mixed Polish Herbs were analysed for the quality control of the results and presented very good accuracy, with relative errors less than 4.2 %, and good precision less than 8.7 %. The element concentrations (in μg g -1 ) obtained in the T. pallida samples analysed showed variation from 2324 to 33897 for Cl, from 3602 to 14450 for Mg, from 132 to 314 for Mn, and 21 to 615 for Na. Values obtained in the analyses of Tradescantia present great variability in the element concentrations. The short irradiation showed to be appropriated for determination of the elements studied in the bio monitoring of air pollution

Piezoelectric properties and temperature stability of Mn-doped Pb(Mg1/3Nb2/3)-PbZrO3-PbTiO3 textured ceramics

OpenAIRE

Yan, Yongke; Cho, Kyung-Hoon; Priya, Shashank

2012-01-01

In this letter, we report the electromechanical properties of textured 0.4Pb(Mg1/3Nb2/3) O-3-0.25PbZrO(3)-0.35PbTiO(3) (PMN-PZT) composition which has relatively high rhombohedral to tetragonal (R-T) transition temperature (TR-T of 160 degrees C) and Curie temperature (T-C of 234 degrees C) and explore the effect of Mn-doping on this composition. It was found that MnO2-doped textured PMN-PZT ceramics with 5 vol.% BaTiO3 template (T-5BT) exhibited inferior temperature stability. The coupling f...

Effect of Mn on microstructures and mechanical properties of Al-Mg-Si-Cu-Cr-V alloy

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Zhao Zhihao

2012-11-01

Full Text Available In order to improve the performances of the Al-Mg-Si-Cu-Cr-V alloy, various amounts of Mn (0-0.9wt.% were added. The effect of this Mn on the microstructures and mechanical properties of Al-Mg-Si-Cu-Cr-V alloys in different states, especially after hot extrution and solid solution treatment, was systematically studied using scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, and mechanical tests at room temperature. The results show that 0.2wt.% Mn can both refine the as-cast microstructure of the alloy and strengthen the extrusion+T6 state alloy without damaging the plasticity badly due to the formation of Al15(FeMn3Si2 and Al15Mn3Si2 dispersoids. Compared with the extrusion+T6 state alloy without Mn addition, the ultimate tensile strength and yield strength of the alloy with 0.2wt.% Mn addition are increased from 416.9 MPa to 431.4 MPa, 360.8 MPa to 372 MPa, respectively. The elongation of the extrusion+T6 state alloy does not show obvious change when the Mn addition is less than 0.5wt.%, and for the alloy with 0.2wt.% Mn addition its elongation is still as high as 15.6%. However, when over 0.7wt.% Mn is added to the alloy, some coarse, stable and refractory AlVMn and Al(VMnSi phases form. These coarse phases can reduce the effect of Mn on the inhibition of re-crystallization; and they retain the angular morphology permanently after the subsequent deformation process and heat treatment. This damages the mechanical properties of the alloy.

Grain refining effect of magnetic field on Mg2Ni0.8Mn0.2 hydrogen storage alloys during rapid quenching

International Nuclear Information System (INIS)

Jiang, Chenxi; Wang, Haiyan; Chen, Xiangrong; Tang, Yougen; Lu, Zhouguang; Wang, Yazhi; Liu, Zuming

2013-01-01

The effect of static magnetic field treatment for synthesis of Mg 2 Ni 0.8 Mn 0.2 alloys during rapid quenching was investigated in this paper. X-ray diffraction (XRD) and scanning electron microscope (SEM) results show that the transversal static magnetic field can effectively refine the grain size, producing nanocrystalline inside. This distinct phenomenon is probably attributed to the Lorentz force suppressing the crystallization of the hydrogen storage alloys and the thermoelectric effect. Mainly due to the grain refinement, the discharge capacity of Mg 2 Ni 0.8 Mn 0.2 alloy is raised from 79 to about 200 mA h g −1 . It is confirmed that Mg 2 Ni 0.8 Mn 0.2 alloy by magnetic field assisted approach possesses enhanced electrochemical kinetics and relatively high corrosion resistance against the alkaline solution, thus resulting in higher electrochemical properties

Synthesize and electrochemical characterization of Mg-doped Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 cathode material

International Nuclear Information System (INIS)

Wang, Dan; Huang, Yan; Huo, Zhenqing; Chen, Li

2013-01-01

Highlights: • Layered Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 (2x = 0, 0.01, 0.02, 0.05) were synthetized. • Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 exhibit enhanced electrochemical properties. • The improved performance is attributed to enhanced structure stability. -- Abstract: Mg-doped Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 as a Li-rich cathode material of lithium-ion batteries were prepared by co-precipitation method and ball-milling treatment using Mg(OH) 2 as a dopant. Scanning electron microscopy (SEM), ex situ X-ray powder diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvantatic charge/discharge were used to investigate the effect of Mg doping on structure and electrochemical performance. Compared with the bare material, Mg-doped materials exhibit better cycle stabilities and superior rate capabilities. Li[Li 0.2 Ni 0.195 Mn 0.595 Mg 0.01 ]O 2 displays a high reversible capacity of 226.5 mAh g −1 after 60 cycles at 0.1 C. The excellent cycle performance can be attributed to the improvement in structure stability, which is verified by XRD tests before and after 60 cycles. EIS results show that Mg doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance

Nanosized spinel oxide catalysts for CO-oxidation prepared via CoMnMgAl quaternary hydrotalcite route

Energy Technology Data Exchange (ETDEWEB)

Mokhtar, M., E-mail: mmoustafa@kau.edu.s [Chemistry Department, Faculty of Science, King Abdulaziz University, 21589 Jeddah, P.O. Box 80203 (Saudi Arabia); Basahel, S.N.; Al-Angary, Y.O. [Chemistry Department, Faculty of Science, King Abdulaziz University, 21589 Jeddah, P.O. Box 80203 (Saudi Arabia)

2010-03-18

Catalytic activity of the Co-Mn-Mg-Al mixed oxide spinel catalysts was examined in CO oxidation by O{sub 2}. The prepared catalysts were characterized by chemical analysis (ICP), infrared spectroscopy (FTIR), thermal analysis (TG, DTG), powder X-ray diffraction (XRD), surface area measurements, and scanning electron microscopy (SEM).The calcined hydrotalcite-like precursor was composed of spinel-like Co-Mn-Mg-Al mixed oxide as the only XRD crystalline phases. The nanosized spinel oxide catalysts produced by calcination of hydrotalcites showed higher S{sub BET} than CoMn-hydrotalcite samples as calcination led to dehydroxylation and carbonate decomposition of anions in interlayer spaces. All the catalysts showed 100% CO conversion at high temperature even those calcined at 800 {sup o}C. A catalyst with Co/Mn = 4 and calcined at 500 {sup o}C showed 100% CO conversion at 160 {sup o}C. Moreover, this catalyst exhibited quite good durability without deactivation in 60 h stability test.

Optical properties of Ni2+ and radiation defects in MgF sub 2 and MnF sub 2

Science.gov (United States)

Feuerhelm, L. N.

1980-03-01

The radiation defects in pure MgF2 were made by observating the polarized absorption, luminescence, and excitation spectra in electron-irradiated MgF2. Additionally, studies of the absorption, emission, excitation, and temperature dependence of the lifetimes of transitions in nickel-doped MgF2 and MnF2 were accomplished, as well as the observation of radiation effects on these crystals. The absorption band at about 320 nm in irradiated MgF2 is identified to be due to the F2(D2b) center, and to have an emission at about 450 nm. Analysis of the temperature dependence of this band indicates a dominant phonon mode of 255 cm(-1) for the excited state. The F2(C1) center is identified with an absorption of about 360 nm and an emission of 410 nm. An absorption peak at 300 nm, for which no corresponding emission was found, is tentatively identified to be the F3-center, and to have a dominant phonon mode of 255 cm(-1). The temperature dependence of the lifetimes of transitions in nickel-doped MgF2 is analyzed by the quantum mechanical single configuration coordinate model of Struck and Fonger, and a complete configuration coordinate model is made for this crystal. Similar studies are made in MnF2:Ni.

Radioactivity of β / γ and the Content of Ca, Fe, Mn, Mg, Na on the Spring of Ponorogo East Java Lime Area

International Nuclear Information System (INIS)

Sutjipto

2002-01-01

Radioactivity of β / γ and the content of Ca, Fe, Mn, Mg, Na on the source of Ponorogo East-Java lime area has been studied. This research was carried out to know radioactivity of β / γ and the content of Ca, Fe, Mn, Mg, Na on the spring of different three places were Ngebel-lake source, Ngembak source and Gonggang source. Samples taken, preparation and analysis based on the procedures of environmental radioactivity analysis and water sampling guidelines. The instrument used for the analysis radioactivity were low level β counter modified P3TM-BATAN Yogyakarta with detector GM and spectrometer γ with detector Ge(Li). Radioactivity of β (gross) from the source of different three places (β ≤ 1 Bq/L) are lower than the value of PPRI No. 20/1990. Radioactivity of γ comes from the natural radionuclides of Tl-208 and K-40 are lower than 1 Bq/L for the different of three places, respectively. The metals concentration of Ngebel-lake source were Ca ≤ 14.34 ppm; Fe ≤ 0.04 ppm; Mn ≤ 0.02 ppm; Mg ≤ 6.75 ppm; Na ≤ 14.63 ppm, Ngembak source were Ca ≤ 11.6 ppm; Fe ≤ 0.04 ppm; Mn ≤ 0.02 ppm; Mg ≤ 11.13 ppm; Na ≤ 16.75 ppm and Gonggang source were Ca ≤ 13.78 ppm; Fe ≤ 0.26 ppm; Mn ≤ 0.02 ppm; Mg ≤ 6.13 ppm; Na ≤ 15.00 ppm. The water of Ngebel-lake source, Ngembak source and Gonggang source can be classified as B category water based on radioactivity and the content of the metals concentration in its. (author)

Effect of Y on the bio-corrosion behavior of extruded Mg-Zn-Mn alloy in Hank's solution

International Nuclear Information System (INIS)

He Weiwei; Zhang Erlin; Yang Ke

2010-01-01

The bio-corrosion properties of Mg-Zn-Mn alloys with and without Y in Hank's solution at 37 deg. C were investigated by using electrochemical test and electrochemical impedance spectra (EIS). The results of open circuit potential (OCP) and polarization tests indicated that Y could reduce the cathodic current density. A passivative stage appeared in the Tafel curve of the Y containing magnesium alloy, indicating that a passivative film was formed on the surface of the Y containing magnesium alloy. EIS results showed that the Y containing alloy had higher charge transfer resistance and film resistance, but lower double layer capacity than the alloy without the Y element. The surface reaction product identification by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed that the surface corrosion products were hydroxide and phosphate (Mg 3 Ca 3 (PO 4 ) 4 ) for Mg-Zn-Mn alloy and phosphate (MgNaPO 4 ) for the Y containing Mg-Zn-Mn alloys. The XPS results also showed that a Y 2 O 3 protective film was formed on the surface of the Y containing magnesium alloy which contributed mainly to the low cathodic current density and the high resistance.

First principles study of structural, electronic, magnetic and elastic properties of Mg{sub 0.75}TM{sub 0.25}S (TM=Mn, Fe, Co, Ni)

Energy Technology Data Exchange (ETDEWEB)

Gous, M.H., E-mail: gousph@hotmail.fr; Meddour, A., E-mail: a_meddour@yahoo.fr; Bourouis, Ch., E-mail: bourouisse_ch@yahoo.fr

2017-01-15

The objective of this work is to predict the structural, electronic, magnetic and elastic properties of Mg{sub 1−x}TM{sub x}S (TM=Mn, Fe, Co and Ni) compound in the zinc blende Ferromagnetic phase using first principal approach. The structural and elastic properties are performed using the generalized gradient approximation proposed by Wu and Cohen(WC-GGA). However, the electronic and magnetic properties have been performed using modified Becke-Johnson potential combined with the LDA correlation (mBJLDA). The results show that all compounds Mg{sub 1−x}Mn{sub x}S, Mg{sub 1−x}Fe{sub x}S and Mg{sub 1−x}Ni{sub x}S exhibit a half-metallic ferromagnetic character with 100% spin-polarization at the Fermi level, except Mg{sub 1−x}Co{sub x}S is a metal. For each compounds study here, the total magnetic momentum is an integer equal to magnetic moments of TM atom in their free space charge value. Due to the p–d hybridization, there is a small local magnetic moment on the Mg and S sites; whereas, the local magnetic moments of TM atom reduce from their free space charge value. In addition, we investigate the mechanical behavior of MgS and Mg{sub 1−x}TM{sub x}S; all compounds studied here are mechanically stable and exhibit a strong anisotropic behavior. - Highlights: • Our results could be a prediction for coming works. • According to our results of electronic properties: Mg{sub 0.75}Co{sub 0.25}S is metal. Mg{sub 0.75}Mn{sub 0.25}S, Mg{sub 0.75}Fe{sub 0.25}S and Mg{sub 0.75}Ni{sub 0.25}S exhibit half-metallic ferromagnetic behavior with 100% spin polarization at Fermi level. • We found that MgS and Mg{sub 0.75}TM{sub 0.25}S (TM=Mn, Fe, Co and Ni) compounds are mechanically stable, ductile materials and have an anisotropic Young's Modulus. • It is likely that these materials have a high Curie temperature.

Synergistic effects of composition and heat treatment on microstructure and properties of vacuum die cast Al-Si-Mg-Mn alloys

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Jun-jie Xu

2018-03-01

Full Text Available The purpose of this study was to prepare high-quality Al-Si-Mg-Mn alloy with a good combination of strength and ductility employing the vacuum-assisted high-pressure die cast process. An orthogonal study of heat treatments was conducted to design an optimized T6 heat treatment process for both Al-10%Si-0.3%Mg-Mn and Al-11%Si-0.6%Mg-Mn alloys. The results demonstrate that no obvious blisters and warpage were observed in these two alloys with solid solution treatment. After the optimal T6 heat treatment of 530°C×3h + 165°C×6h, Al-11%Si-0.6%Mg-Mn alloy has better mechanical properties, of which tensile strength, yield strength and elongation reached 377.3 MPa, 307.8 MPa and 9%, respectively. The improvement of mechanical properties can be attributed to the high density of needle-like β″(Mg5Si6 precipitation after aging treatment and the fine and spherical eutectic Si particles uniformly distributed in the α-Al matrix.

Effects of homogenization on microstructures and properties of a new type Al-Mg-Mn-Zr-Ti-Er alloy

International Nuclear Information System (INIS)

He, L.Z.; Li, X.H.; Liu, X.T.; Wang, X.J.; Zhang, H.T.; Cui, J.Z.

2010-01-01

Research highlights: These new type alloys are very potential for increased use in aerospace and automobile industries. However, most of published reports have focused on the effects of Cu, Sc, Zr, Ag, rare metals and Si additions, Portevin-LeChatelier effect, corrosion properties, friction stir welding and superplasticity in 5000-series aluminum alloy, few investigated on Er and stepped homogenization on the precipitation of dispersoids in Al-Mg-Mn alloy. The purpose of this work was to study the effects of Er and homogenization treatment on mechanical properties and microstructural evolution in new type Al-Mg-Mn-Er alloy. - Abstract: Microstructural evolutions and mechanical properties of Al-Mg-Mn-Zr-Ti-Er alloy after homogenization were investigated in detail by optical microscope (OM), scanning electronic microscope (SEM), transmission electronic microscope (TEM), energy dispersive spectrum (EDS) and tensile test. A maximum tensile strength is obtained when the alloy homogenized at 510 deg. C for 16 h. With increasing preheating temperature (200-400 deg. C), the strength of the alloy finial homogenized at 490 deg. C for 16 h increases. When the preheating temperature is ≥300 deg. C, the strengths of the two-step homogenized alloys are higher than those of the single homogenized alloys. The preheating stage plays an important role in the microstructures and properties of the final homogenized alloy. Many fine (Mn,Fe)Al 6 precipitates when the preheating temperature is 400 deg. C. ErAl 3 phase cannot be observed during preheating stage. Plenty of fine (Mn,Fe)Al 6 and ErAl 3 precipitate in finial homogenized alloy when the preheating temperature is ≥300 deg. C. The Al-Mg-Mn-Zr-Ti-Er alloy is effectively strengthened by substructure and dispersoids of (Mn,Fe)Al 6 and ErAl 3 .

(Zn, Mg)2GeO4:Mn2+ submicrorods as promising green phosphors for field emission displays: hydrothermal synthesis and luminescence properties.

Science.gov (United States)

Shang, Mengmeng; Li, Guogang; Yang, Dongmei; Kang, Xiaojiao; Peng, Chong; Cheng, Ziyong; Lin, Jun

2011-10-07

(Zn(1-x-y)Mg(y))(2)GeO(4): xMn(2+) (y = 0-0.30; x = 0-0.035) phosphors with uniform submicrorod morphology were synthesized through a facile hydrothermal process. X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL), and cathodoluminescence (CL) spectroscopy were utilized to characterize the samples. SEM and TEM images indicate that Zn(2)GeO(4):Mn(2+) samples consist of submicrorods with lengths around 1-2 μm and diameters around 200-250 nm, respectively. The possible formation mechanism for Zn(2)GeO(4) submicrorods has been presented. PL and CL spectroscopic characterizations show that pure Zn(2)GeO(4) sample shows a blue emission due to defects, while Zn(2)GeO(4):Mn(2+) phosphors exhibit a green emission corresponding to the characteristic transition of Mn(2+) ((4)T(1)→(6)A(1)) under the excitation of UV and low-voltage electron beam. Compared with Zn(2)GeO(4):Mn(2+) sample prepared by solid-state reaction, Zn(2)GeO(4):Mn(2+) phosphors obtained by hydrothermal process followed by high temperature annealing show better luminescence properties. In addition, codoping Mg(2+) ions into the lattice to substitute for Zn(2+) ions can enhance both the PL and CL intensity of Zn(2)GeO(4):Mn(2+) phosphors. Furthermore, Zn(2)GeO(4):Mn(2+) phosphors exhibit more saturated green emission than the commercial FEDs phosphor ZnO:Zn, and it is expected that these phosphors are promising for application in field-emission displays.

Validation of FNAA method for testing the elements of Mn, Cr and Mg on the Gajahwong river sediment sample

International Nuclear Information System (INIS)

Wisjachudin Faisal; Elin Nuraini

2010-01-01

Validation of elements of Mn, Cr and Mg by using FNAA method has been performed. NBS SRM 8704 (Bufallo River Sediment), was used as the standard reference material, with the neutrons generator operating condition at the optimum voltage of 110 kV. Energy and channel number of calibration lines obtained with the standard equation as y = 1.034 x + 151.21. From the analysis of SRM, the results show that only Mg can be analyzed, because Cr and Mn are located at the same peak point (interferences), so that they can not be analyzed. From the analysis for Mg element (SRM), the precision and the accuration obtained are 95.53 % and 94.88%, while the average price of expanded uncertainty for the various locations is 0.233 ± 0.012. Mg content analysis result at various locations along the river Gajahwong ranging from 85.41 – 103.55 ppm. When compared with previous studies showing the elements content of Fe, Al and Si is much higher than Mg content. (author)

Microstructure, mechanical properties and bio-corrosion properties of Mg-Zn-Mn-Ca alloy for biomedical application

International Nuclear Information System (INIS)

Zhang Erlin; Yang Lei

2008-01-01

Microstructure, mechanical properties and bio-corrosion properties of as-cast Mg-Zn-Mn-Ca alloys were investigated for biomedical application in detail by optical microscopy, scanning electronic microscopy (SEM), mechanical properties testing and electrochemical measurement. SEM and optical microscopy observation indicated that the grain size of the as-cast alloys significantly decreased with the increasing of Ca content up to 0.5 wt.%. Further increasing of Ca content did not refine the grain more. The phase constitute was mainly controlled by the atomic ratio of Zn to Ca. When the ratio was more than 1.0-1.2, the alloy was mainly composed of primary Mg and lamellar eutectic (α-Mg + Ca 2 Mg 6 Zn 3 ), while the alloy was composed of primary Mg and divorced eutectic (α-Mg + Mg 2 Ca + Ca 2 Mg 6 Zn 3 ) when the atomic ratio was less than 1.0-1.2. The yield strength of the as-cast alloy increased but the elongation and the tensile strength increased first and then decreased with the increasing of Ca content. It was thought that Mg 2 Ca phase deteriorated the tensile strength and ductility. Electrochemical measurements indicated that Mg 2 Ca phase improved the corrosion resistance of the as-cast alloy

Magnetic and Moessbauer study of Mg{sub 0.9}Mn{sub 0.1}Cr{sub x}Fe{sub 2-x}O{sub 4} ferrites

Energy Technology Data Exchange (ETDEWEB)

Elzain, M., E-mail: elzain@squ.edu.om; Widatallah, H.; Gismelseed, A.; Bouziane, K.; Yousif, A.; Al Rawas, A.; Al-Omari, I.; Sellai, A. [Sultan Qaboos University, Department of Physics, College of Science (Oman)

2006-02-15

The ferrites Mg{sub 0.9}Mn{sub 0.1}Cr{sub x}Fe{sub 2-x}O{sub 4} (0x0.9) were prepared using the conventional double sintering method. The XRD showed that the samples maintain a single spinel cubic phase. The Moessbauer measurements were carried out at room and liquid nitrogen temperatures. From the area ratios of the A and B sites, it was found that the Fe cation population of the A and B sites decreases in proportion to Cr concentration. The contact hyperfine fields at the A and B sites were found to decrease with increasing Cr contents. This was found to be in approximate agreement with the results of magnetization measurement. The distributions of Mg and Mn cations versus Cr concentration were also determined using the Moessbauer and magnetization results. The Curie temperatures were determined and found to agree with the reported values. As the Cr contents increases the relative magnetization, was found to increase at low temperatures and decreases at higher temperatures.

Hydrogen storage properties of LaMgNi{sub 3.6}M{sub 0.4} (M = Ni, Co, Mn, Cu, Al) alloys

Energy Technology Data Exchange (ETDEWEB)

Yang, Tai [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Zhai, Tingting; Yuan, Zeming; Bu, Wengang [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Xu, Sheng [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Zhang, Yanghuan, E-mail: zhangyh59@sina.com [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China)

2014-12-25

Highlights: • La–Mg–Ni system AB{sub 2}-type alloys were prepared by induction melting. • Structures and lattice parameters were analysed by XRD. • Hydrogen absorption/desorption performances were studied. • Mechanisms of hydrogen absorption capacity fading were investigated. - Abstract: LaMgNi{sub 3.6}M{sub 0.4} (M = Ni, Co, Mn, Cu, Al) alloys were prepared through induction melting process. The phase compositions and crystal structures were characterised via X-ray diffraction (XRD). The hydrogen storage properties, including activation performance, hydrogen absorption capacity, cycle stability, alloy particle pulverisation and plateau pressure, were systemically investigated. Results show that Ni, Co, Mn and Cu substitution alloys exhibit multiphase structures comprising the main phase LaMgNi{sub 4} and the secondary phase LaNi{sub 5}. However, the secondary phase of the Al substitution alloy changes into LaAlNi{sub 4}. The lattice parameters and cell volumes of the LaMgNi{sub 4} phase follow the order Ni < Co < Al < Cu < Mn. Activation is simplified through partial substitution of Ni with Al, Cu and Co. The hydrogen absorption capacities of all of the alloys are approximately 1.7 wt.% at the first activation process; however, they rapidly decrease with increasing cycle number. In addition, the stabilities of hydriding and dehydriding cycles decrease in the order Al > Co > Ni > Cu > Mn. Hydriding processes result in numerous cracks and amorphisation of the LaMgNi{sub 4} phase in the alloys. The p–c isotherms were determined by a Sieverts-type apparatus. Two plateaus were observed for the Ni, Co and Al substitution alloys, whereas only one plateau was found for Mn and Cu. This result was caused by the amorphisation of the LaMgNi{sub 4} phase during the hydriding cycles. Reversible absorption and desorption of hydrogen are difficult to achieve. Substitutions of Ni with Co, Mn, Cu and Al significantly influence the reduction of hysteresis between

Influence of Iron in AlSi10MgMn Alloy

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Žihalová M.

2014-12-01

Full Text Available Presence of iron in Al-Si cast alloys is common problem mainly in secondary (recycled aluminium alloys. Better understanding of iron influence in this kind of alloys can lead to reduction of final castings cost. Presented article deals with examination of detrimental iron effect in AlSi10MgMn cast alloy. Microstructural analysis and ultimate tensile strength testing were used to consider influence of iron to microstructure and mechanical properties of selected alloy.

Effect of Cr and Mn addition and heat treatment on AlSi3Mg casting alloy

Energy Technology Data Exchange (ETDEWEB)

Tocci, Marialaura, E-mail: m.tocci@unibs.it [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy); Donnini, Riccardo, E-mail: riccardo.donnini@cnr.it [National Research Council of Italy (CNR), Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Via R. Cozzi 53, 20125 Milan (Italy); Angella, Giuliano, E-mail: giuliano.angella@cnr.it [National Research Council of Italy (CNR), Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Via R. Cozzi 53, 20125 Milan (Italy); Pola, Annalisa, E-mail: annalisa.pola@unibs.it [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy)

2017-01-15

In the present paper the effect of heat treatment on an AlSi3Mg alloy with and without Cr and Mn addition was investigated. Beside the well-known modification of the morphology of Fe-containing intermetallics, it was found that Cr and Mn allowed the formation of dispersoids in the aluminium matrix after solution heat treatment at 545 °C, as shown by scanning transmission electron microscope observations. These particles were responsible of the enhanced Vickers microhardness of the aluminium matrix in comparison with the base alloy after solution treatment and quenching, according to dispersion hardening mechanism. The presence of these particles was not affected by ageing treatment, which instead allowed the precipitation of β-Mg{sub 2}Si, as shown by the elaboration of differential scanning calorimeter curves. The formation of dispersoids and the study of their effect on mechanical properties can represent an interesting development for applications at high temperatures of casting alloys due to their thermal stability compared to other strengthening phases as β-Mg{sub 2}Si. - Highlights: •Cr and Mn successfully modified the morphology of Fe-containing intermetallics. •Cr- and Mn-dispersoids formed in the aluminium matrix during solution treatment. •Dispersion hardening was detected after solution treatment for Cr-containing alloy. •The dispersion hardening effect was maintained after ageing treatment.

Mild hydrothermal crystal growth of new uranium(IV) fluorides, Na3.13Mg1.43U6F30 and Na2.50Mn1.75U6F30: Structures, optical and magnetic properties

Science.gov (United States)

Yeon, Jeongho; Smith, Mark D.; Tapp, Joshua; Möller, Angela; zur Loye, Hans-Conrad

2016-04-01

Two new uranium(IV) fluorides, Na3.13Mg1.43U6F30 (1) and Na2.50Mn1.75U6F30 (2), were synthesized through an in situ mild hydrothermal route, and were structurally characterized by single crystal X-ray diffraction. The compounds exhibit complex crystal structures composed of corner- or edge-shared UF9 and MF6 (M=Mg, Mn) polyhedra, forming hexagonal channels in the three-dimensional framework, in which ordered or disordered divalent metal and sodium atoms reside. The large hexagonal voids contain the nearly regular M(II)F6 octahedra and sodium ions, whereas the small hexagonal cavities include M(II) and sodium ions on a mixed-occupied site. Magnetic susceptibility measurements yielded effective magnetic moments of 8.36 and 11.6 μB for 1 and 2, respectively, confirming the presence and oxidation states of U(IV) and Mn(II). The large negative Weiss constants indicate the spin gap between a triplet and a singlet state in the U(IV). Magnetization data as a function of applied fields revealed that 2 exhibits paramagnetic behavior due to the nonmagnetic singlet ground state of U(IV) at low temperature. UV-vis diffuse reflectance and X-ray photoelectron spectroscopy data were also analyzed.

Preparation and electrical properties of Mn{sub 1.05−y}Co{sub 1.95−x−z−w}Ni{sub x}Mg{sub y}Al{sub z}Fe{sub w}O{sub 4} NTC ceramic derived from microemulsion method

Energy Technology Data Exchange (ETDEWEB)

Xia, Junbo [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, Qing, E-mail: zhaoq@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); Gao, Bo [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chang, Aimin, E-mail: changam@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); Zhang, Bo; Ma, Renjun [Key Laboratory of Functional Materials and Devices under Special Environments, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, CAS, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2014-04-05

Highlights: • The NTC thermister nano-powders Mn{sub 1.05−y}Co{sub 1.95−x−z−w}Ni{sub x}Mg{sub y}Al{sub z}Fe{sub w}O{sub 4} were prepared by microemulsion method. • The metal ions were subsided after twice sediment reaction. • The specimens show good electrical properties by doping some nontransition metals. -- Abstract: The NTC thermistor nano-powders of Mn{sub 1.05−y}Co{sub 1.95−x−z−w}Ni{sub x}Mg{sub y}Al{sub z}Fe{sub w}O{sub 4} were prepared by microemulsion method. Scanning electron microscope (SEM) image showed that the particles were well distributed. The mean particle-size was 72 nm. The structure of the precursor was investigated with Fourier infrared spectrometer (FI). The compositions of the powder and the as-sintered ceramic were evaluated by Energy Disperse Spectroscopy (EDS). X-ray diffraction (XRD) result indicated that the sintered samples were in the spinel structure. The room temperature resistivity ρ{sub 25}, material constant B{sub 25/85} and activation energies of the NTC thermistor are in the range of 1173–19,059 Ω cm, 3169–3771 k, 0.2672–0.3136 eV. The room temperature resistivity and B{sub 25/85} constant were found to increase with Al{sub 2}O{sub 3} content. The Mn{sub 0.9}Co{sub 1.2}Ni{sub 0.21}Mg{sub 0.15}Al{sub 0.09}Fe{sub 0.45}(A2) and Mn{sub 0.9}Co{sub 1.2}Ni{sub 0.27}Mg{sub 0.15}Al{sub 0.03}Fe{sub 0.45}(A3) specimens both showed a 200 °C resistance drift (ΔR/R) within 10% after aging at 910 °C for 600 h.

Mn induced 1 × 2 reconstruction in the τ-MnAl(0 0 1) surface

Science.gov (United States)

Guerrero-Sánchez, J.; Takeuchi, Noboru

2018-05-01

We report on first principles total energy calculations to describe the structural, electronic and magnetic properties of MnAl(0 0 1) surfaces. We have concentrated in structural models having 1 × 1 and 1 × 2 periodicities, since recent experiments of the similar MnGa(0 0 1) surface have found 1 × 1 and 1 × 2 reconstructions. Our calculations show the existence of two stable structures for different ranges of chemical potential. A 1 × 1 surface is stable for Al-rich conditions, whereas a Mn-induced 1 × 2 reconstruction appears after increasing the Mn chemical potential up to Mn-rich conditions. It is important to notice that experimentally, Mn rich conditions are important for improved magnetic properties. The Mn layers in both structures have ferromagnetic arrangements, but they are aligned antiferromagnetically with the almost no magnetic Al atoms. Moreover, the on top Mn atoms, which produce the 1 × 2 reconstruction, align antiferromagnetically with the second layer Mn atoms. These findings are similar to those obtained experimentally in MnGa thin films grown by molecular beam epitaxy. Therefore, this method could also be used to grow the proposed MnAl films.

Fractionation and risk assessment of Fe and Mn in surface sediments from coastal sites of Sonora, Mexico (Gulf of California).

Science.gov (United States)

Jara-Marini, Martín E; García-Camarena, Raúl; Gómez-Álvarez, Agustín; García-Rico, Leticia

2015-07-01

The aim of this study was to evaluate Fe and Mn distribution in geochemical fractions of the surface sediment of four oyster culture sites in the Sonora coast, Mexico. A selective fractionation scheme to obtain five fractions was adapted for the microwave system. Surface sediments were analyzed for carbonates, organic matter contents, and Fe and Mn in geochemical fractions. The bulk concentrations of Fe ranged from 10,506 to 21,918 mg/kg (dry weight, dry wt), and the bulk concentrations of Mn ranged from 185.1 to 315.9 mg/kg (dry wt) in sediments, which was low and considered as non-polluted in all of the sites. The fractionation study indicated that the major geochemical phases for the metals were the residual, as well as the Fe and Mn oxide fractions. The concentrations of metals in the geochemical fractions had the following order: residual > Fe and Mn oxides > organic matter > carbonates > interchangeable. Most of the Fe and Mn were linked to the residual fraction. Among non-residual fractions, high percentages of Fe and Mn were linked to Fe and Mn oxides. The enrichment factors (EFs) for the two metals were similar in the four studied coasts, and the levels of Fe and Mn are interpreted as non-enrichment (EF < 1) because the metals concentrations were within the baseline concentrations. According to the environmental risk assessment codes, Fe and Mn posed no risk and low risk, respectively. Although the concentrations of Fe and Mn were linked to the residual fraction, the levels in non-residual fractions may significantly result in the transference of other metals, depending on several physico-chemical and biological factors.

Essential trace (Zn, Cu, Mn and toxic (Cd, Pb, Cr elements in the liver of birds from Eastern Poland

Directory of Open Access Journals (Sweden)

Komosa A.

2012-01-01

Full Text Available We have focused our study on the concentrations of essential heavy metals (Zn, Cu and Mn and non-essential trace metals (Pb, Cd and Cr in the livers of birds from Eastern Poland. The largest mean amount of Zn - as much as 279 mg/kg dry mass (d.m. - was found in mute swans. However, only in one of the analysed buzzard specimens the concentration of Zn, found to be 664 mg/kg d.m., exceeded the level indicative of poisoning for this element. Birds specializing in catching rodents accumulated Mn in their livers in a very narrow range of concentrations, around 5.0 mg/kg d.m. on average. The range of mean Mn concentrations (around 6.5 mg/kg d.m. was also found to be narrow for piscivorous birds. The highest mean levels of Pb were found in mute swans (2.7 mg/kg d.m., and the highest levels of Cd (2.0 mg/kg d.m. for rooks. Concentrations of total Cr above detection level were found in 22 specimens (53.7%, and concentration values were highest for rooks. Analyses showed that the concentrations of biogenic elements did not exceed the levels indicative of poisoning (except in one specimen. The study demonstrated that lead shots remain a hazard to water ecosystems. Pb, Cd and Cr levels in the livers of omnivorous and piscivorous species indicate the permanent presence of these elements in the environment and may confirm the thesis about the growing role of electronic waste, including metallic e-waste, in the emission of the total amount of contamination with these elements.

Joining of Cu-Mg-Mn Aluminum Alloy with Linear Friction Welding

OpenAIRE

A. Medvedev; V. Bychkov; A. Selivanov; Yu. J. Ershova; B. Bolshakov; I.V. Alexаndrov; F. F. Musin

2014-01-01

Al-Cu-Mg-Mn alloy samples were joined together with linear friction welding in two conditions, as is, without pretreatment, and after etching the welding interface. The effect of the welding interface condition was evaluated based on microstructure analysis, microhardness and tensile testing at room temperature. Also, the temperature distribution during welding was estimated with an analytical one-dimensional heat conduction model of the welding process and welding process data

Enhanced persistent red luminescence in Mn2+-doped (Mg,Zn)GeO3 by electron trap and conduction band engineering

Science.gov (United States)

Katayama, Yumiko; Kayumi, Tomohiro; Ueda, Jumpei; Tanabe, Setsuhisa

2018-05-01

The effect of Zn substitution on the persistent luminescence properties of MgGeO3:Mn2+-Ln3+ (Ln = Eu and Yb) red phosphors was investigated. The intensity of the persistent luminescence of the Eu3+ co-doped phosphors increased with increasing Zn content, whereas that of the Yb3+ co-doped samples decreased. For both series of lanthanide co-doped samples, the thermoluminescence (TL) glow peak shifted to the lower temperature side with increasing Zn content. These persistent luminescence properties were well explained in terms of lowering of the bottom of the conduction band relative to the ground state of the divalent lanthanide ions. Especially, in Eu3+ co-doped system, TL peak shifted from 520 K to 318 K by 50% Zn substitution. The persistent radiance of the (Mg0.5 Zn0.5)GeO3: Mn2+-Eu3+ sample at 1 h after ceasing UV light was 46 times stronger than that of MgGeO3:Mn2+-Eu3+, and 11 times stronger than that of ZnGa2O4: Cr3+ standard deep red persistent phosphor.

DNA-assisted assembly of carbon nanotubes and MnO2 nanospheres as electrodes for high-performance asymmetric supercapacitors.

Science.gov (United States)

Guo, Chun Xian; Chitre, Amey Anil; Lu, Xianmao

2014-03-14

A DNA-assisted assembly approach is developed to fabricate a capacitor-type electrode material, DNA-functionalized carbon nanotubes (CNTs@DNA), and a battery-type electrode material, DNA@CNTs-bridged MnO2 spheres (CNTs@DNA-MnO2), for asymmetric supercapacitors. An energy density of 11.6 W h kg(-1) is achieved at a power density of 185.5 W kg(-1) with a high MnO2 mass loading of 4.2 mg cm(-2). It is found that DNA assembly plays a critical role in the enhanced supercapacitor performance. This is because while DNA molecules functionalize carbon nanotubes (CNTs) via π-π stacking, their hydrophilic sugar-phosphate backbones also promote the dispersion of CNTs. The resultant CNTs@DNA chains can link multiple MnO2 spheres to form a networked architecture that facilitates charge transfer and effective MnO2 utilization. The improved performance of the asymmetric supercapacitors indicates that DNA-assisted assembly offers a promising approach to the fabrication of high-performance energy storage devices.

Structure and magnetic properties of La{sub 2/3}Sr{sub 1/3}MnO{sub 3}/CaMnO{sub 3} multilayers

Energy Technology Data Exchange (ETDEWEB)

Granada, Mara [Centro Atomico Bariloche and Instituto Balseiro, CNEA-UNC, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina)]. E-mail: granadam@cab.cnea.gov.ar; Sirena, Martin [Centro Atomico Bariloche and Instituto Balseiro, CNEA-UNC, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Steren, Laura B. [Centro Atomico Bariloche and Instituto Balseiro, CNEA-UNC, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Leyva, Gabriela [Depto. de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz y Constituyentes, 1650 San Martin (Argentina)

2004-12-31

Structural and magnetic properties of manganite-based multilayers, La{sub 2/3}Sr{sub 1/3}MnO{sub 3}/CaMnO{sub 3}, composed of ferromagnetic metals and antiferromagnetic insulator barriers are investigated in this work. Compounds of similar lattice parameters were used to build the samples, so we expect an excellent stacking of the different layers along the structure. To get a first insight of this system, the crystalline structure of a series of samples, grown on (1 0 0) SrTiO{sub 3} and (1 0 0) MgO single-crystalline substrates, has been studied. X-ray diffraction patterns show that the structure is strongly textured in the (1 0 0) direction when grown on SrTiO{sub 3}, regardless the composition of the bottom layer. A different result is found on the same system grown on MgO: when the buffer layer is CaMnO{sub 3}, the structure grows in the (1 1 0) orientation while it grows in the (1 0 0) direction when the bottom layer is La{sub 2/3}Sr{sub 1/3}MnO{sub 3}. Magnetic coupling of the ferromagnetic layers across the antiferromagnetic spacer has been studied with magnetization measurements.

Synthesis and photoluminescence of Eu3+ and Mn2+ doped double phosphates KMLa(PO4)2 (M = Zn, Mg)

International Nuclear Information System (INIS)

Pan Yuexiao; Zhang Qinyuan; Jiang Zhonghong

2006-01-01

Two compounds, KMgLa(PO 4 ) 2 and KZnLa(PO 4 ) 2 doped with Eu 3+ and Mn 2+ ions, have been synthesized by a conventional solid-state method at 850 deg. C. Structures of KMgLa(PO 4 ) 2 and KZnLa(PO 4 ) 2 have been investigated and confirmed by X-ray diffraction and photoluminescence spectra. The results indicate that the compounds have remained the monoclinic structure of LaPO 4 with space group of C s when (K + , Mg 2+ ) or (K + , Zn 2+ ) could substitute half of the La 3+ ions. Under an ultraviolet source, KMgLa(PO 4 ) 2 :Mn 2+ has shown a bright red phosphorescent color, while KZnLa(PO 4 ) 2 :Mn 2+ has shown an orange-red emission which is assigned to the electronic transition of 4 T 1 ( 4 G)- 6 A 1 ( 6 S) of Mn 2+ in strong crystal field

Single Low Dose Primaquine (0.25 mg/kg Does Not Cause Clinically Significant Haemolysis in G6PD Deficient Subjects.

Directory of Open Access Journals (Sweden)

Germana Bancone

.7% were greater than in G6PD normal subjects (0.3%, -0.8 and -1.7% but were clinically insignificant. Fractional drops in haemoglobin concentration larger than 25% following single dose primaquine were observed in 1.8% of the population but were asymptomatic.The single low dose (0.25mg/kg of primaquine is clinically well tolerated and can be used safely without prior G6PD testing in populations with high prevalence of G6PD deficiency. The present evidence supports a broader use of low dose primaquine without G6PD testing for the treatment and elimination of falciparum malaria.ClinicalTrials.gov NCT01872702.

Contraction Twinning Dominated Tensile Deformation and Subsequent Fracture in Extruded Mg-1Mn (Wt Pct) at Ambient Temperature

Science.gov (United States)

Chakkedath, A.; Maiti, T.; Bohlen, J.; Yi, S.; Letzig, D.; Eisenlohr, P.; Boehlert, C. J.

2018-03-01

Due to their excellent strength-to-weight ratio, Mg alloys are attractive for applications where weight savings are critical. However, the limited cold formability of wrought Mg alloys severely restricts their widespread usage. In order to study the role that deformation twinning might play in limiting the elongation-to-failure ({ɛ} f ), in-situ tensile tests along the extrusion axis of Mg-1Mn (wt pct) were performed at 323 K, 423 K, and 523 K. The alloy exhibited a strong basal texture such that most of the grains experienced compression along their -axis during deformation. At 323 K, fracture occurred at about 10 pct strain. Although basal, prismatic, and pyramidal slip activity was observed along with extension twinning, contraction twinning significantly influenced the deformation, and such twins evolved into {10{\\bar{1}} 1}-{10{\\bar{1}} 2} double twins. Crystal plasticity simulation showed localized shear deformation within the contraction twins and double twins due to the enhanced activity of basal slip in the reoriented twin volume. Due to this, the twin-matrix interface was identified to be a potential crack initiation site. Thus, contraction twins were considered to have led to the failure of the material at a relatively low strain, suggesting that this deformation mode is detrimental to the cold formability of Mg and its alloys. With increasing temperature, there was a significant decrease in the activity of contraction twinning as well as extension twinning, along with a decrease in the tensile strength and an increase in the {ɛ} f value. A combination of basal, prismatic, and pyramidal slips accounted for a large percentage of the observed deformation activity at 423 K and 523 K. The lack of contraction twinning was explained by the expected decrease in the critical resolved shear stress values for pyramidal slip, and the improved {ɛ} f values at elevated temperatures were attributed to the vanishing activity of contraction twinning.

Contraction Twinning Dominated Tensile Deformation and Subsequent Fracture in Extruded Mg-1Mn (Wt Pct) at Ambient Temperature

Science.gov (United States)

Chakkedath, A.; Maiti, T.; Bohlen, J.; Yi, S.; Letzig, D.; Eisenlohr, P.; Boehlert, C. J.

2018-06-01

Due to their excellent strength-to-weight ratio, Mg alloys are attractive for applications where weight savings are critical. However, the limited cold formability of wrought Mg alloys severely restricts their widespread usage. In order to study the role that deformation twinning might play in limiting the elongation-to-failure ({ɛ} _{ {f}}), in-situ tensile tests along the extrusion axis of Mg-1Mn (wt pct) were performed at 323 K, 423 K, and 523 K. The alloy exhibited a strong basal texture such that most of the grains experienced compression along their -axis during deformation. At 323 K, fracture occurred at about 10 pct strain. Although basal, prismatic, and pyramidal slip activity was observed along with extension twinning, contraction twinning significantly influenced the deformation, and such twins evolved into {10{\\bar{1}}1}-{10{\\bar{1}}2} double twins. Crystal plasticity simulation showed localized shear deformation within the contraction twins and double twins due to the enhanced activity of basal slip in the reoriented twin volume. Due to this, the twin-matrix interface was identified to be a potential crack initiation site. Thus, contraction twins were considered to have led to the failure of the material at a relatively low strain, suggesting that this deformation mode is detrimental to the cold formability of Mg and its alloys. With increasing temperature, there was a significant decrease in the activity of contraction twinning as well as extension twinning, along with a decrease in the tensile strength and an increase in the {ɛ} _{ {f}} value. A combination of basal, prismatic, and pyramidal slips accounted for a large percentage of the observed deformation activity at 423 K and 523 K. The lack of contraction twinning was explained by the expected decrease in the critical resolved shear stress values for pyramidal slip, and the improved {ɛ} _{ {f}} values at elevated temperatures were attributed to the vanishing activity of contraction twinning.

Effect of soil type and application method on nutrients absorption and utilization by grape plants 1-Absorption and utilization of manganese using Mn-54

International Nuclear Information System (INIS)

Mohamed, F.A.; Sharaf, A.N.M.; Khamis, M.A.; Sharaf, M.M.

2000-01-01

This work was conducted to study effect of soil type and application method on absorption, translocation and utilization of Mn by grape plants. One year old rooted cuttings of grape (Cv. Ruby seedless) were transplanted in plastic containers filled with 15 kg of three different soils, i.e. clay loam soil, sandy soil and calcareous soil. Fertilization treatments were as follows: Tap water (control) (T1); soil application of N, P,K and Mg (T2); T2 plus soil application of Fe, Mn and Zn (T4). Also, pot experiment was carried out using Mn SO4 at 5ppm for soil application and at 0.5% for foliar application and Mn-54 was used for labelling both solutions. Manganese contents in different organs of grape plant were significantly increased by the three fertilization treatments as compared to those of control. Moreover, highest Mn level was obtained due to foliar application of micro elements and soil application of macro elements T 4 . followed by soil application of both macro-and micro elements T 3 , soil application of macro elements only T2 and control T1

Analysis of (Ba,Ca,Sr)3MgSi2O8:Eu2+, Mn2+ phosphors for application in solid state lighting

International Nuclear Information System (INIS)

Han, J.K.; Piqutte, A.; Hannah, M.E.; Hirata, G.A.; Talbot, J.B.; Mishra, K.C.; McKittrick, J.

2014-01-01

The luminescence properties of Eu 2+ and Mn 2+ co-activated (Ba,Ca,Sr) 3 MgSi 2 O 8 phosphors prepared by combustion synthesis were studied. Eu 2+ -activated (Ba,Ca,Sr) 3 MgSi 2 O 8 has a broad blue emission band centered at 450–485 nm and Eu 2+ –Mn 2+ -activated (Ba,Ca,Sr) 3 MgSi 2 O 8 exhibits a red emission around 620–703 nm, depending on the relative concentrations of Ba, Ca and Sr. The particle size of Eu 2+ and Mn 2+ co-activated (Ba,Ca) 3 MgSi 2 O 8 ranges from 300 nm to 1 μm depending on the metal ion and are agglomerated due to post-synthesis, high temperature annealing. The green emission of Ba 3 MgSi 2 O 8 originates from secondary phases (Ba 2 SiO 4 and BaMgSiO 4 ) confirmed by emission spectra and X-ray diffraction patterns. The secondary phases of Ba 3 MgSi 2 O 8 are removed by the addition of Sr. The quantum efficiencies range from 45% to 70% under 400 nm excitation and the lifetime of red emission of Ba 3 MgSi 2 O 8 decreases significantly with increasing temperature, which is 54% at 400 K of that at 80 K compared to that of blue emission (90% at 400 K of that at 80 K). -- highlights: • (Ba,Ca,Sr) 3 MgSi 2 O 8 :Eu 2+ , Mn 2+ phosphors were prepared by a combustion synthesis method. • The emission spectra consist of broad blue-emission band and red-emission band. • The quantum efficiencies range between 45% and 70%, depending on the relative concentrations of Ba, Ca and Sr. • The secondary phases were eliminated by additions of Sr. • Lifetime of the red-emission decreases with increasing temperature, suggesting that these phosphors are not useful for solid state lighting applications

Magnetic properties and magnetocaloric effects in Mn1.2Fe0.8P1-xGex compounds

International Nuclear Information System (INIS)

Ou, Z Q; Wang, G F; Lin Song; Tegus, O; Brueck, E; Buschow, K H J

2006-01-01

We have studied the magnetic properties and magnetocaloric effects in the Mn 1.2 Fe 0.8 P 1-x Ge x compounds with x = 0.2, 0.22, 0.3, 0.4 and 0.5. X-ray diffraction patterns show that the Mn 1.2 Fe 0.8 P 1-x Ge x compounds crystallize in the hexagonal Fe 2 P-type crystal structure. The magnetic moments of the Mn 1.2 Fe 0.8 P 1-x Ge x compounds measured at 5 K and 5 T increase with increasing Ge content. The Curie temperature increases strongly and the magnetic entropy change has a maximum around 233 K for the compound with x = 0.22, which is about 19 and 31 J kg -1 K -1 for a field change of 2 and 5 T, respectively

Pressure dependence of resistivity and magnetic properties in a Mn1.9Cr0.1Sb alloy

Directory of Open Access Journals (Sweden)

D. V. Maheswar Repaka

2017-12-01

Full Text Available We report magnetic-field and hydrostatic pressure dependent electrical resistivity and magnetic properties of a Mn1.9Cr0.1Sb alloy. Upon cooling, the magnetization of Mn1.9Cr0.1Sb exhibits a first-order ferrimagnetic to antiferromagnetic transition at the exchange inversion temperature, TS = 261 K under a 0.1 T magnetic field. Our experimental results show that TS decreases with increasing magnetic field but increase with increasing hydrostatic pressure. The pressure induced transition is accompanied by a large positive baro-resistance of 30.5% for a hydrostatic pressure change of 0.69 GPa. These results show that the lattice parameters as well as the bond distance between Mn-Mn atoms play a crucial role in the magnetic and electronic transport properties of Mn1.9Cr0.1Sb. This sample also exhibits a large inverse magnetocaloric effect with a magnetic entropy change of ΔSm = +6.75 J/kg.K and negative magnetoresistance (44.5% for a field change of 5 T at TS in ambient pressure which may be useful for magnetic cooling and spintronics applications.

Luminescence property and emission enhancement of YbAlO3:Mn4+ red phosphor by Mg2+ or Li+ ions

Science.gov (United States)

Cao, Renping; Luo, Wenjie; Xu, Haidong; Luo, Zhiyang; Hu, Qianglin; Fu, Ting; Peng, Dedong

2016-03-01

YbAlO3:Mn4+, YbAlO3:Mn4+, Li+, and YbAlO3:Mn4+, Mg2+ phosphors are synthesized by high temperature solid-state reaction method in air. Their crystal structures and luminescence properties are investigated. Photoluminescence excitation (PLE) spectrum monitored at 677 nm contains broad PLE band with three PLE peaks located at ∼318, 395, and 470 nm within the range 220-600 nm. Emission spectra with excitation 318 and 470 nm exhibit three emission band peaks located at ∼645, 677, and 700 nm in the range of 610-800 nm and their corresponding chromaticity coordinates are about (x = 0.6942, y = 0.3057). The possible luminous mechanism of Mn4+ ion is analyzed by the simple energy level diagram of Mn4+ ion. The optimum Mn4+-doped concentration in YbAlO3:Mn4+ phosphor is about 0.4 mol% and the luminescence lifetime of YbAlO3:0.4%Mn4+ phosphor is ∼0.59 ms. Emission intensity of YbAlO3:0.4%Mn4+ phosphor can be enhanced ∼6 times after Mg2+ ion is co-doped and it is ∼2 times when Li+ ion is co-doped. The content in the paper is useful to research new Mn4+-doped luminescence materials and improve luminescence property of other Mn4+-doped phosphors.

Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

International Nuclear Information System (INIS)

Du, Jiandi; Ding, Dongyan; Xu, Zhou; Zhang, Junchao; Zhang, Wenlong; Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua; Chen, Renzong; Huang, Yuanwei; Tang, Jinsong

2017-01-01

Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al 8 Cu 4 Ce phase, Al 6 Cu 6 La phase and Al 6 (Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

Analysis of Co, Cr and Mn Concentrations in Atmospheric Dry Deposition in Hamadan City

Directory of Open Access Journals (Sweden)

P. Shokri Ragheb

2016-07-01

Full Text Available Introduction & Objective: Heavy metals are major pollutants that can spread in the atmosphere with particulate matter and dust and because of the toxic and carcinogenic effects, their meas-urement and control is very important. Therefore, this study was conducted to assess Co, Cr and Mn concentration in the atmospheric dry deposition collected from Hamadan city in 2014. Materials & Methods: After collection of 12 dust samples from 3 sampling stations and their laboratory preparation, metals concentrations were determined using ICP–OES. All statistical analyses were performed using the SPSS statistical package. Results: The results showed that the minimum and maximum mean concentrations of Co were 0.19 and 0.29 mg/kg for high and low traffic intensity sampling stations, respectively. The min and max mean concentrations of Cr were 0.65and 1.02 mg/kg for high traffic intensity and suburb sampling stations, respectively and the min and max mean concentrations of Mn were 7.23and 8.82 mg/kg for high and low traffic intensity sampling stations , respectively. Also comparing the mean concentrations of assessed metals with WHO permissible limits showed a significant difference (P< 0.05. The mean concentrations of metals were signifi-cantly lower than the maximum permissible limits. Conclusion: Although the mean concentrations of Co, Cr and Mn are lower than the standard levels, lack of continuous monitoring of heavy metals concentrations in the dust and particu-late matters in the air can lead to the entrance of various types of toxic pollutants such as heavy metals into the air and result in adverse health effects. (Sci J Hamadan Univ Med Sci 2016; 23 (2:149-156

Effect of Pulse Laser Welding Parameters and Filler Metal on Microstructure and Mechanical Properties of Al-4.7Mg-0.32Mn-0.21Sc-0.1Zr Alloy

Directory of Open Access Journals (Sweden)

Irina Loginova

2017-12-01

Full Text Available The effect of pulse laser welding parameters and filler metal on microstructure and mechanical properties of the new heat-treatable, wieldable, cryogenic Al-4.7Mg-0.32Mn-0.21Sc-0.1Zr alloy were investigated. The optimum parameters of pulsed laser welding were found. They were 330–340 V in voltage, 0.2–0.25 mm in pulse overlap with 12 ms duration, and 2 mm/s speed and ramp-down pulse shape. Pulsed laser welding without and with Al-5Mg filler metal led to the formation of duplex (columnar and fine grains as-cast structures with hot cracks and gas porosity as defects in the weld zone. Using Al-5Ti-1B filler metal for welding led to the formation of the fine grain structure with an average grain size of 4 ± 0.2 µm and without any weld defects. The average concentration of Mg is 2.8%; Mn, 0.2%; Zr, 0.1%; Sc, 0.15%; and Ti, 2.1% were formed in the weld. The ultimate tensile strength (UTS of the welded alloy with AlTiB was 260 MPa, which was equal to the base metal in the as-cast condition. The UTS was increased by 60 MPa after annealing at 370 °C for 6 h that was 85% of UTS of the base alloy.

Improving the Elevated-Temperature Properties by Two-Step Heat Treatments in Al-Mn-Mg 3004 Alloys

Science.gov (United States)

Liu, K.; Ma, H.; Chen, X. Grant

2018-05-01

In the present work, two-step heat treatments with preheating at different temperatures (175 °C, 250 °C, and 330 °C) as the first step followed by the peak precipitation treatment (375 °C/48 h) as the second step were performed in Al-Mn-Mg 3004 alloys to study their effects on the formation of dispersoids and the evolution of the elevated-temperature strength and creep resistance. During the two-step heat treatments, the microhardness is gradually increased with increasing time to a plateau after 24 hours when first treated at 250 °C and 330 °C, while there is a minor decrease with time when first treated at 175 °C. Results show that both the yield strength (YS) and creep resistance at 300 °C reach the peak values after the two-step treatment of 250 °C/24 h + 375 °C/48 h. The formation of dispersoids is greatly related to the type and size of pre-existing Mg2Si precipitated during the preheating treatments. It was found that coarse rodlike β ' -Mg2Si strongly promotes the nucleation of dispersoids, while fine needle like β ″-Mg2Si has less influence. Under optimized two-step heat treatment and modified alloying elements, the YS at 300 °C can reach as high as 97 MPa with the minimum creep rate of 2.2 × 10-9 s-1 at 300 °C in Al-Mn-Mg 3004 alloys, enabling them as one of the most promising candidates in lightweight aluminum alloys for elevated-temperature applications.

Mn-substituted perovskites RECoxMn1-xO3: a comparison between magnetic properties of LaCoxMn1-xO3 and GdCoxMn1-xO3

Directory of Open Access Journals (Sweden)

Barahona, P.

2008-08-01

Full Text Available Cooperative phenomena constitute important mechanisms to explain the magnetic properties of the perovskite manganites REMnO3, in which the rare-earth and/or Mn is partially replaced by divalent elements. In this way, the manganese ion changes its valence state (Mn3+ Mn4+, triggering strong magnetic interactions. In this work we describe the case of GdCoxMn1-xO3 (0.0 ≤ x ≤ 1.0 for which the antiferromagnetic interaction between the Gd sublattice and the Mn/Co network leads to a reversal of the magnetic moment at low temperature. No inversion is observed for the LaCoxMn1-xO3 series, in which the ordering temperature may attain a maximum of 235 K for LaCo0.50Mn0.50O3, while it is only 120 K for similar Co/Mn ratio in the case of GdCo0.50Mn0.50O3. Magnetic properties are described in terms of two regimes: one, for x 3 manganite and another one, for x > 0.5, when Mn substitutes Co in the GdCoO3 cobaltite, while the magnetic interactions are maximized at x(Co = 0.50. This hypothesis is discussed in terms of the respective oxidation states of both manganese (Mn3+ / Mn4+ and cobalt (Co2+ / Co3+.El fenómeno cooperativo constituye un importante mecanismo para explicar las propiedades magnéticas de las perovskitas manganitas TRMnO3, en las que el catión de tierra rara, TR, y/o el catión Mn3+ son parcialmente reemplazados por cationes divalentes. Por esta vía el ión de manganeso cambia de estado de valencia (Mn3+ Mn4+, generando fuertes interacciones magnéticas. En el presente trabajo se describe el caso de las soluciones sólidas GdCoxMn1-xO3 (0.0 ≤ x ≤ 1.0 para las que la interacción antiferromagnética entre la subred del Gd3+ y la red Mn/Co lleva a una inversión del momento magnético a baja temperatura. No se ha observado inversión para la serie LaCoxMn1-xO3, en que la temperatura de orden puede alcanzar un máximo de 235K para LaCo0.50Mn0.50O3, mientras que en el caso de GdCo0.50Mn0.50O3, en que sí se observa inversión, la

EPR and optical properties of Eu{sup 2+} and Mn{sup 2+} co-doped MgSrAl{sub 10}O{sub 17} blue–green light emitting powder phosphors

Energy Technology Data Exchange (ETDEWEB)

Singh, N. [Department of Chemical Engineering, Konkuk University, Seoul 143-701 (Korea, Republic of); Singh, Vijay, E-mail: vijayjiin2006@yahoo.com [Department of Chemical Engineering, Konkuk University, Seoul 143-701 (Korea, Republic of); Sivaramaiah, G. [Department of Physics, Government College (M), Kadapa 516 004 (India); Rao, J.L. [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Singh, Pramod K. [Materials Research Laboratory, Sharda University, Greater Noida 201 310 (India); Pathak, M.S. [Department of Chemical Engineering, Konkuk University, Seoul 143-701 (Korea, Republic of); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440 033 (India); Mohapatra, M. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2016-10-15

Strong blue–green light emitting MgSrAl{sub 10}O{sub 17}:Eu{sup 2+},Mn{sup 2+} phosphor was synthesized by a low-temperature initiated, self-propagating and gas producing combustion process in a very short time (<5 min). Structural characterization of the luminescent material was studied with X-ray diffraction analysis and energy-dispersive X-ray analysis. The absorption spectrum exhibits bands due to Eu{sup 2+} and Mn{sup 3+} ions. The excitation spectrum shows a peak at 337 nm. Upon excitation at 337 nm, the emission spectrum exhibits an intense band centered at 462 nm due to transitions from the 4f{sup 6}5d{sup 1} to the 4f{sup 7} configuration of the Eu{sup 2+} ions, whereas sharp peak at 513 nm attributed to {sup 4}T{sub 1}→{sup 6}A{sub 1} transition of Mn{sup 2+} ions. The X-band EPR spectra of MgSrAl{sub 10}O{sub 17}:Eu{sup 2+},Mn{sup 2+} showed the presence of Eu{sup 2+} and Mn{sup 2+} ions.

Electrochemical hydrogen storage behaviour of as-cast and as-spun RE-Mg-Ni-Mn-based alloys applied to Ni-MH battery

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yanghuan; Hou, Zhonghui; Hu, Feng [Inner Mongolia University of Science and Technology, Baotou (China). Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources; Central Iron and Steel Research Institute, Beijing (China). Dept. of Functional Material Research; Cai, Ying [Inner Mongolia University of Science and Technology, Baotou (China). Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources; Qi, Yan; Zhao, Dongliang [Central Iron and Steel Research Institute, Beijing (China). Dept. of Functional Material Research

2016-09-15

La-Mg-Ni-Mn-based AB{sub 2}-type La{sub 1-x}Ce{sub x}MgNi{sub 3.5}Mn{sub 0.5} (x = 0, 0.1, 0.2, 0.3, 0.4) alloys were fabricated by melt spinning. X-ray diffraction and scanning electron microscopy revealed that the experimental alloys consisted of a major phase LaMgNi{sub 4} and a secondary phase LaNi{sub 5}. The Ce substitution for La and melt spinning refined the grains of the alloys clearly. Electrochemical tests showed that the as-cast and as-spun alloys exhibited excellent activation capability. With the increase in the spinning rate and Ce content, the discharge capacities of the alloys initially increased and then decreased, whereas their cycle stabilities always increased. Moreover, the electrochemical kinetics of the alloys initially increased and then decreased with the growth of Ce content and spinning rate. The major reason leading to the capacity degradation of the alloy electrodes was determined to be the pulverisation of the alloy particles and the corrosion and oxidation of the alloy surface.

Variation of heavy metal and micro and macro element concentrations of bread and durum wheats and their relationship in grain of Turkish wheat cultivars.

Science.gov (United States)

Harmankaya, Mustafa; Ozcan, Mehmet Musa; Gezgin, Sait

2012-09-01

The 64 varieties displayed a large variation for all mineral elements, investigated Fe, Mn and Zn, ranging from 24.2 to 43.1 mg/kg, 27.6 to 64.8 mg/kg and 10.4 to 38.2 mg/kg, respectively. The mean Ca, K, Mg, Na, P and S concentrations in wheat rain varieties amounted to 378, 4,266, 1,183, 317, 3,513 and 1,542 mg/kg, respectively. Ca, K, Mg, Na, P and S contents of wheat varieties changed at the levels between 266 and 531 mg/kg, 3,029 and 5,566 mg/kg, 972 and 1,525 mg/kg, 277 and 368 mg/kg, 2,422 and 4,610 mg/kg and 1,241 to 2,052 mg/kg, respectively. The concentrations of Al, Cu, Fe, Mn and Zn of durum wheat samples were found at high levels. The mean Al, Cr, Mo, Ni, Cu, Fe, Mn and Zn concentrations in durum wheat varieties amounted to 10.93, 0.47, 0.72, 0.72, 5.37, 34.9, 37.28 and 20.88 mg/kg, respectively.

Structural and magnetic properties of MnCo1-xVxGe compounds

International Nuclear Information System (INIS)

Meng, G.H.; Tegus, O.; Zhang, W.G.; Song, L.; Huang, J.H.

2010-01-01

The structural and magnetic properties of MnCo 1-x V x Ge (x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20 and 0.30) compounds were investigated by means of X-ray diffraction, scanning electron microscopy and magnetization measurements. The MnCo 1-x V x Ge compounds crystallize in the orthorhombic TiNiSi-type crystal structure for x ≤ 0.02 and in the hexagonal Ni 2 In-type structure for x > 0.02. The magnetization measurements show that the MnCo 1-x V x Ge compounds exhibit a complex magnetic behavior. The Curie temperature can be tuned from 360 K to 148 K by increasing x. The maximal magnetic-entropy change is 3.9 J/kg K for x = 0.06 at a field change from 0 to 1.5 T at about 265 K.

Circadian rhythm in concentrations of Mg, K, Ca and Mn in Japanese morning glory during flowering process

International Nuclear Information System (INIS)

Ikeue, Natsuko; Tanoi, Keitaro; Furukawa, Jun; Yokota, Harumi; Okuni, Yoko; Nakanishi, Tomoko M.

2001-01-01

Concentrations of 4 trace elements, Mg, K, Ca and Mn, in each tissues of Japanese morning glory were analyzed during the flower development. To determine the element amount, neutron activation analysis with gamma-ray spectroscopy was performed. In this study, we focused on the movement of the trace elements especially with short-day treatment. Each element showed its specific distribution in the parts of a plant. The concentration of each element was changed rhythmically within a day. It was noted that, in the apical bud, concentrations of Mg, Ca and Mn were decreased from 5 h (2 h before light was on) to 7 h and increased again after 9 h. (author)

Circadian rhythm in concentrations of Mg, K, Ca and Mn in Japanese morning glory during flowering process

Energy Technology Data Exchange (ETDEWEB)

Ikeue, Natsuko; Tanoi, Keitaro; Furukawa, Jun; Yokota, Harumi; Okuni, Yoko; Nakanishi, Tomoko M. [Tokyo Univ. (Japan). Graduate School of Agricultural and Life Sciences

2001-06-01

Concentrations of 4 trace elements, Mg, K, Ca and Mn, in each tissues of Japanese morning glory were analyzed during the flower development. To determine the element amount, neutron activation analysis with gamma-ray spectroscopy was performed. In this study, we focused on the movement of the trace elements especially with short-day treatment. Each element showed its specific distribution in the parts of a plant. The concentration of each element was changed rhythmically within a day. It was noted that, in the apical bud, concentrations of Mg, Ca and Mn were decreased from 5 h (2 h before light was on) to 7 h and increased again after 9 h. (author)

Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

Energy Technology Data Exchange (ETDEWEB)

Du, Jiandi [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Ding, Dongyan, E-mail: dyding@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, Zhou; Zhang, Junchao; Zhang, Wenlong [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua [Huafon NLM Al Co., Ltd, Shanghai 201506 (China); Chen, Renzong; Huang, Yuanwei; Tang, Jinsong [Shanghai Huafon Materials Technology Institute, Shanghai 201203 (China)

2017-01-15

Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al{sub 8}Cu{sub 4}Ce phase, Al{sub 6}Cu{sub 6}La phase and Al{sub 6}(Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

Cardiovascular effects of MnDPDP and MnCl2 in dogs with acute ischaemic heart failure

International Nuclear Information System (INIS)

Karlsson, J.O.G.; Pedersen, H.K.; Sager, G.; Refsum, H.; Nycomed Imaging AS, Oslo

1997-01-01

Purpose: To examine the cardiovascular effects of MnDPDP in a model of acute heart failure in the dog, and to compare these effects with those of MnCl 2 . Material and Methods: The study involved slow i.v. infusion of either 10, 60 and 300 μmol/kg of MnDPDP, or 1, 6 and 30 μmol/kg MnCl 2 , in increasing doses to groups of 5 dogs. Acute ischaemic heart failure was first induced by injection of polystyrene microspheres (50±10 μm) into the left coronary artery until a stable left ventricular end-diastolic pressure of approximately 20 mm Hg was achieved. The following test parameters were measured: Left ventricular end-diastolic pressure; the first derivatives of maximum rate of left ventricular contraction and relaxation; mean aortic pressure; pulmonary artery pressure; right atrial pressure; cardiac ouput; heart rate; QT-time; PQ-time; QRS-width; and plasma catecholamines. Results: Slow infusion of MnDPDP at doses up to and including 12 times the clinical dose was well tolerated in dogs without further depression of cardiovascular function during acute ischaemic heart failure. At 300 μmol/kg, i.e. 60 times the human dose, only minor haemodynamic and electrophysiological effects were seen, and these were similar to those seen after administration of 30 μmol/kg MnCl 2 . (orig./AJ)

Magnetocaloric effects in Mn1.35Fe0.65P1−xSix compounds

International Nuclear Information System (INIS)

Geng Yao-Xiang; Tegus O; Bi Li-Ge

2012-01-01

The structural and magnetocaloric properties of Mn 1.35 Fe 0.65 P 1−x Si x compounds are investigated. The Si-substituted compounds, Mn 1.35 Fe 0.65 P 1−x Si x with x = 0.52, 0.54, 0.55, 0.56, and 0.57, are prepared by high-energy ball milling and the solid-state reaction. The X-ray diffraction shows that the compounds crystallize into the Fe 2 P-type hexagonal structure with space group P6-bar2m. The magnetic measurements show that the Curie temperature of the compound increases from 253 K for x = 0.52 to 296 K for x = 0.56. The isothermal magnetic-entropy change of the Mn 1.35 Fe 0.65 P 1−x Si x compound decreases with the Si content increasing. The maximal value of the magnetic-entropy change is about 7.0 J/kg·K in the Mn 1.35 Fe 0.65 P 0.48 Si 0.52 compound with a field change of 1.5 T. The compound quenched in water possesses a larger magnetic entropy change and a smaller thermal hysteresis than the non-quenched samples. The thermal hysteresis of the compound is less than 3.5 K. The maximum adiabatic temperature change is about 1.4 K in the Mn 1.35 Fe 0.65 P 0.45 Si 0.55 compound with a field change of 1.48 T. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

A first-principle investigation of spin-gapless semiconductivity, half-metallicity, and fully-compensated ferrimagnetism property in Mn{sub 2}ZnMg inverse Heusler compound

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaotian [School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130 (China); Institute for Superconducting & Electronic Materials (ISEM), University of Wollongong, Wollongong 2500 (Australia); Cheng, Zhenxiang, E-mail: cheng@uow.edu.au [Institute for Superconducting & Electronic Materials (ISEM), University of Wollongong, Wollongong 2500 (Australia); Khenata, Rabah [Laboratoire de Physique Quantique, de la Matière et de la Modélisation Mathématique (LPQ3M), Université de Mascara, Mascara 29000 (Algeria); Rozale, Habib [Condensed Matter and Sustainable Development Laboratory, Physics Department, University of Sidi-Bel-Abbès, 22000 Sidi-Bel-Abbès (Algeria); Wang, Jianli [Institute for Superconducting & Electronic Materials (ISEM), University of Wollongong, Wollongong 2500 (Australia); Wang, Liying; Guo, Ruikang [School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130 (China); Liu, Guodong, E-mail: gdliu1978@126.com [School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130 (China)

2017-02-01

Recently, spin-gapless semiconductors (SGSs) and half-metallic materials (HMMs) have received considerable interest in the fields of materials sciences and solid-state physics because they can provide a high degree of spin polarization in electron transport. The results on band structure calculations reveal that the metallic fully-compensated ferrimagnet (M-FCF) Mn{sub 2}ZnMg becomes half-metallic fully-compensated ferrimagnet (HM-FCF), fully-compensated ferrimagnetic semiconductor (FCF-S) and fully-compensated ferrimagnetic spin-gapless semiconductor (FCF-SGS) if the uniform strain applied. However, the metallic fully-compensated ferrimagnetism property of the Mn{sub 2}ZnMg is robust to the tetragonalization. The structure stability based on the calculations of the cohesion energy and the formation energy of this compound has been tested. Furthermore, a magnetic state transition from antiferromagentic (AFM) state to non-magnetic (NM) state can be observed at the lattice constant of 5.20 Å. - Highlights: • Mn{sub 2}ZnMg is a M-FCF at its equilibrium lattice constant. • We study the effect of uniform strain on the physical nature transition of Mn{sub 2}ZnMg. • The M-FCF property of the Mn{sub 2}ZnMg is robust to the tetragonalization. • A magnetic phase transition occurs at 5.20 Å.

The Mechanism of Solid State Joining THA with AlMg3Mn Alloy

Directory of Open Access Journals (Sweden)

Kaczorowski M.

2014-06-01

Full Text Available The results of experimental study of solid state joining of tungsten heavy alloy (THA with AlMg3Mn alloy are presented. The aim of these investigations was to study the mechanism of joining two extremely different materials used for military applications. The continuous rotary friction welding method was used in the experiment. The parameters of friction welding process i.e. friction load and friction time in whole studies were changed in the range 10 to 30kN and 0,5 to 10s respectively while forging load and time were constant and equals 50kN and 5s. The results presented here concerns only a small part whole studies which were described elsewhere. These are focused on the mechanism of joining which can be adhesive or diffusion controlled. The experiment included macro- and microstructure observations which were supplemented with SEM investigations. The goal of the last one was to reveal the character of fracture surface after tensile test and to looking for anticipated diffusion of aluminum into THA matrix. The results showed that joining of THA with AlMg2Mn alloy has mainly adhesive character, although the diffusion cannot be excluded.

Mild hydrothermal crystal growth of new uranium(IV) fluorides, Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30}: Structures, optical and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Yeon, Jeongho; Smith, Mark D. [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States); Tapp, Joshua; Möller, Angela [Department of Chemistry and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

2016-04-15

Two new uranium(IV) fluorides, Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} (1) and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30} (2), were synthesized through an in situ mild hydrothermal route, and were structurally characterized by single crystal X-ray diffraction. The compounds exhibit complex crystal structures composed of corner- or edge-shared UF{sub 9} and MF{sub 6} (M=Mg, Mn) polyhedra, forming hexagonal channels in the three-dimensional framework, in which ordered or disordered divalent metal and sodium atoms reside. The large hexagonal voids contain the nearly regular M(II)F{sub 6} octahedra and sodium ions, whereas the small hexagonal cavities include M(II) and sodium ions on a mixed-occupied site. Magnetic susceptibility measurements yielded effective magnetic moments of 8.36 and 11.6 µ{sub B} for 1 and 2, respectively, confirming the presence and oxidation states of U(IV) and Mn(II). The large negative Weiss constants indicate the spin gap between a triplet and a singlet state in the U(IV). Magnetization data as a function of applied fields revealed that 2 exhibits paramagnetic behavior due to the nonmagnetic singlet ground state of U(IV) at low temperature. UV–vis diffuse reflectance and X-ray photoelectron spectroscopy data were also analyzed. - Graphical abstract: Two new quaternary U(IV) fluorides, Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30}, were crystallized via an in situ reduction step of U(VI) to U(IV) under mild hydrothermal conditions. The compounds show complex crystal structures based on the 3-D building block of U{sub 6}F{sub 30}. Magnetic property measurements revealed that the U(IV) exhibits a nonmagnetic singlet ground state at low temperature with a spin gap. - Highlights: • Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30} have been synthesized and characterized. • The U(IV) fluorides exhibit complex three-dimensional crystal structures. • The

TH-EF-207A-02: Imaging Pancreatic Î{sup 2}-Cell Function with 51/52Mn-PET

Energy Technology Data Exchange (ETDEWEB)

Graves, S; Hernandez, R; England, C; Valdovinos, H; Jeffery, J; Barnhart, T; Cai, W; Nickles, R [University of Wisconsin, Madison, WI (United States)

2016-06-15

Purpose: To image β-cells noninvasively using radio-manganese PET and to develop efficient small cyclotron production of {sup 51}Mn (t1/2=46m, β{sup +}=97%) and {sup 52}Mn (t1/2=5.6d, β{sup +}=29%). Methods: {sup 51}Mn and {sup 52}Mn were produced by 16 MeV proton irradiation (GE PETtrace) of electrodeposited {sup 54}Fe on silver and Cr metal pressed into a silver disc, respectively. {sup 51}Mn was radiochemically isolated from target material by anion exchange chromatography and {sup 52}Mn was isolated by ethanolic anion exchange trap-and-release. A final injectable product of {sup 51}Mn{sup 2+} or {sup 52}Mn{sup 2+} was obtained in 0.01M pH 6.0 NaOAc. To assess pancreatic uptake, fasted ICR mice were administered and intravenous bolus or infusion of {sup 52}Mn{sup 2+}. Additionally, to demonstrate the correlation between β-cell function and {sup 52}Mn{sup 2+} pancreatic uptake, prior to tracer administration groups of ICR mice were administered glibenclamide (5mg/kg) and diazoxide (20 mg/kg) as an insulin release stimulator and blocker, respectively. To validate PET ROI quantification, ex vivo biodistribtution studies were conducted on each subject after the final imaging time-point. Results: Dynamic PET data using a left atrium ROI revealed that {sup 52}Mn{sup 2+} cleared from the blood with a 10 second half-life. Significant uptake was seen in the pancreas (approximately 20% ID/g, SUVmean= 5.5), liver, kidneys, intestine, heart, and thyroid. Pancreatic uptake was found to be highly sensitive to volatile anesthesia administration (p=0.0002), insulin release stimulation by glibenclamide (p=0.017), and by insulin release inhibition by diazoxide (p=0.046). Excellent agreement was found between in vivo PET ROI quantification and ex vivo biodistribution measurements. Conclusion: This work demonstrates the feasibility of using radiomanganese-PET for measuring functional β-cell mass in vivo. The decay characteristics and dosimetric properties of {sup 51}Mn are

Cardiovascular effects of MnDPDP and MnCl{sub 2} in dogs with acute ischaemic heart failure

Energy Technology Data Exchange (ETDEWEB)

Karlsson, J.O.G. [Trondheim Univ. (Norway). Dept. of Physiology and Biomedical Engineering]|[Nycomed Imaging AS, Oslo (Norway). Research and Development; Mortensen, E. [Dept. of Physiology, Inst. of Medical Biology, Univ. of Tromsoe (Norway); Pedersen, H.K. [Dept. of Radiology, The National Hospital, Oslo (Norway); Sager, G. [Dept. of Pharmacology, Inst. of Medical Biology, Univ. of Tromsoe (Norway); Refsum, H. [Inst. for Experimental Medical Research, Ullevaal Hospital, Oslo Univ. (Norway)]|[Nycomed Imaging AS, Oslo (Norway). Research and Development

1997-07-01

Purpose: To examine the cardiovascular effects of MnDPDP in a model of acute heart failure in the dog, and to compare these effects with those of MnCl{sub 2}. Material and Methods: The study involved slow i.v. infusion of either 10, 60 and 300 {mu}mol/kg of MnDPDP, or 1, 6 and 30 {mu}mol/kg MnCl{sub 2}, in increasing doses to groups of 5 dogs. Acute ischaemic heart failure was first induced by injection of polystyrene microspheres (50{+-}10 {mu}m) into the left coronary artery until a stable left ventricular end-diastolic pressure of approximately 20 mm Hg was achieved. The following test parameters were measured: Left ventricular end-diastolic pressure; the first derivatives of maximum rate of left ventricular contraction and relaxation; mean aortic pressure; pulmonary artery pressure; right atrial pressure; cardiac ouput; heart rate; QT-time; PQ-time; QRS-width; and plasma catecholamines. Results: Slow infusion of MnDPDP at doses up to and including 12 times the clinical dose was well tolerated in dogs without further depression of cardiovascular function during acute ischaemic heart failure. At 300 {mu}mol/kg, i.e. 60 times the human dose, only minor haemodynamic and electrophysiological effects were seen, and these were similar to those seen after administration of 30 {mu}mol/kg MnCl{sub 2}. (orig./AJ).

Removal of 54Mn from the mouse body by dilution with stable manganese and by chelation with DTPA

International Nuclear Information System (INIS)

Sato, Itaru; Matsusaka, Naonori; Tsuda, Shuji

1999-01-01

54 Mn is one of the activation products generated in nuclear reactors. This study was carried out to find a method appropriate for the removal of 54 Mn. Intraperitoneal administration of stable manganese effectively promoted the excretion of 54 Mn from the mouse body. The efficacy for removing 54 Mn was estimated to be 56, 67, 77 and 82% for manganese doses of 0.3, 1, 3 and 10 mg/kg, respectively. Oral administration of stable manganese was also effective for the removal of 54 Mn, but the efficacy was inferior to that obtained by intraperitoneal administration because of low gastrointestinal absorption of manganese. Ca-DTPA and Zn-DTPA promoted the excretion of 54 Mn when administered 1 h after administration of 54 Mn, but these chelating agents had little effect when administered after 3 h or more. Zn-DTPA was less effective than Ca-DTPA. These results demonstrate that dilution with stable manganese is more effective than chelation with DTPA for the removal of 54 Mn from the body. (author)

Electrochemical hydrogen-storage properties of La{sub 0.78}Mg{sub 0.22}Ni{sub 2.67}Mn{sub 0.11}Al{sub 0.11}Co{sub 0.52}-M1Ni{sub 3.5}Co{sub 0.6}Mn{sub 0.4}Al{sub 0.}-5 composites

Energy Technology Data Exchange (ETDEWEB)

Huang, Hongxia, E-mail: hhxhunan@126.com [Key Lab of New Processing Technology for Nonferrous Metals and Materials Ministry of Education, Guilin University of Technology, Guilin (China); Li, Guohui [Guangxi Scientific Experiment Center of Mining, Metallurgy and Environment, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin (China); Zhuang, Shuxin [School of Material Science and engineering, Xiamen University of Technology, Xiamen (China)

2013-07-15

For improving the electrochemical properties of nonstoichiometric AB{sub 3} -type La{sub 0.7}8Mg{sub 0.22}Ni{sub 2.67}Mn{sub 0.11}Al{sub 0.11}Co{sub 0.52} alloy as negative electrode of Ni-MH battery, its related composites La{sub 0.78}Mg{sub 0.22}Ni{sub 2.67}Mn{sub 0.11}Al{sub 0.11}Co{sub 0.52}-x wt.% M1Ni{sub 3.5}Co{sub 0.6}Mn{sub 0.4}Al{sub 0.5} (x = 0, 10, 20, 30) were prepared. Analysis by X-ray diffractometry (XRD) revealed that the composites consist mainly of LaNi{sub 5} and La{sub 2}Ni{sub 7} phases. Despite the small decrease in the maximum discharge capacity, the cycle performance was significantly enhanced. Linear polarization (LP), anodic polarization (AP) and potential step discharge experiments revealed that the electrochemical kinetics increases first and then decreases with increasing x. (author)

A new insight of recycling of spent Zn-Mn alkaline batteries: Synthesis of Zn{sub x}Mn{sub 1−x}O nanoparticles and solar light driven photocatalytic degradation of bisphenol A using them

Energy Technology Data Exchange (ETDEWEB)

Qu, Jiao, E-mail: qujiao@bhu.edu.cn [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou, Liaoning 121013 (China); School of Urban and Environmental Sciences, Northeast Normal University, Changchun, Jilin 130024 (China); Feng, Yue; Zhang, Qian [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou, Liaoning 121013 (China); Cong, Qiao [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou, Liaoning 121013 (China); School of Urban and Environmental Sciences, Northeast Normal University, Changchun, Jilin 130024 (China); Luo, Chunqiu [School of Chemistry and Chemical Engineering, Bohai University, Jinzhou, Liaoning 121013 (China); Yuan, Xing [School of Urban and Environmental Sciences, Northeast Normal University, Changchun, Jilin 130024 (China)

2015-02-15

Highlights: • Zn{sub 0.5}Mn{sub 0.5}O nanoparticles synthesized using SABs were cylinder with 60 nm diameter. • Adsorption equilibrium of BPA on Zn{sub x}Mn{sub 1−x}O nanoparticles were achieved in 40 min. • Decomposition yields of BPA were increased with light irradiation and Zn{sub x}Mn{sub 1−x}O nanoparticles. • The findings have positive effects on solving the recycling of SABs. - Abstract: This work focuses on the synthesis of Zn{sub 0.1}Mn{sub 0.9}O, Zn{sub 0.3}Mn{sub 0.7}O, and Zn{sub 0.5}Mn{sub 0.5}O nanoparticles using Zn-Mn spent alkaline batteries (SABs) as raw materials and their applications for photocatalytic degradation of bisphenol A in water. Zn-Mn SABs were manually dismantled into scrap (including plastics, copper cap, zinc crust, and carbon rod) and powder. The mashed zinc crust and pretreated powder were successively added into H{sub 2}SO{sub 4} and NH{sub 3}⋅H{sub 2}O, and the formed precipitates were characterized. The yield (wt) of synthesis of Zn{sub 0.5}Mn{sub 0.5}O (ZnMnO{sub 3}) nanoparticles was 57.1%. The synthesized Zn{sub 0.5}Mn{sub 0.5}O nanoparticles were cylinder, with a length of 60 nm. Afterwards, the removal efficiencies of bisphenol A (BPA) under solar light irradiation with the recovered Zn{sub x}Mn{sub 1−x}O nanoparticles were investigated: (1) the adsorption equilibrium of BPA on Zn{sub x}Mn{sub 1−x}O nanoparticles could be achieved after approximate 40 min. The saturation absorbance of BPA was about 32.40 ± 4.76 mg g{sup −1}, 20.40 ± 3.60 mg g{sup −1}, and 14.50 ± 4.55 mg g{sup −1} by Zn{sub 0.1}Mn{sub 0.9}O, Zn{sub 0.3}Mn{sub 0.7}O, and Zn{sub 0.5}Mn{sub 0.5}O nanoparticles, respectively; (2) compared with the 21.7 ± 1.6% degradation of BPA (only solar light irradiation for 180 min), the combination of solar light irradiation and Zn{sub 0.1}Mn{sub 0.9}O, Zn{sub 0.3}Mn{sub 0.7}O, and Zn{sub 0.5}Mn{sub 0.5}O nanoparticles could lead to 59.41 ± 4.32%, 83.43 ± 2.73%, and 71.22 ± 4

Integral data test of HENDL1.0/MG and visualBUS with neutronics shielding experiments. Pt.1

International Nuclear Information System (INIS)

Gao Chunjing; Deng Tieru; Xu Dezheng; Li Jingjing; Wu Yican

2004-01-01

HENDL1.0/MG, a multi-group working library of the Hybrid Evaluated Nuclear Data Library, was home-developed by the FDS Team of ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) on the basis of several national data libraries. To validate and qualify the process of producing HENDL1.0/MG, simulating calculations of a series of existent spherical shell benchmark experiments (Al, Mo, Co, Ti, Mn, W, Be and V) have been performed with HENDL1.0/MG and the multifunctional neutronics code system named VisualBUS home-developed also by FDS Team. (authors)

Magnetization and ESR studies of La{sub 0.67}(Ca{sub 1−x}Mg{sub x}){sub 0.33}MnO{sub 3} systems

Energy Technology Data Exchange (ETDEWEB)

Sendil Kumar, A., E-mail: sendilphy@gmail.com [School of Physics, University of Hyderabad, Hyderabad, Telangana, 500 046 (India); Ravinder Reddy, K [School of Engineering Sciences & Technology, University of Hyderabad, Hyderabad, Telangana, 500 046 (India); Bhatnagar, Anil K. [School of Physics, University of Hyderabad, Hyderabad, Telangana, 500 046 (India); School of Engineering Sciences & Technology, University of Hyderabad, Hyderabad, Telangana, 500 046 (India)

2015-08-05

Highlights: • Mg substitution reduces the ferromagnetic strength. • Inhomogeneous broadening is due to phase separation. • Griffiths phase existence is probed. - Abstract: Magnetization studies and line shape analysis on Electron Spin Resonance (ESR) spectra of La{sub 0.67}(Ca{sub 1−x}Mg{sub x}){sub 0.33}MnO{sub 3} are carried out. In paramagnetic phase well above T{sub c}, the ESR spectra are single Lorentzian but below and near T{sup ∗}{sub ΔHPP}, (T{sup ∗}{sub ΔHPP} is temperature at which line width is minimum) inhomogeneous broadening with asymmetry in the signal is observed due to phase separation. The resonance field below T{sup ∗}{sub ΔHPP} decreases with decreasing temperature. Above T{sub c} the intensity of the ESR spectra obeys the thermally activated model (Arrhenius behavior). Substitution of Mg weakens the ferromagnetic interaction and evolution of change in lineshape near T{sub c} is an evidence of Griffiths phase (coexistence of paramagnetic and ferromagnetic) in Mg doped LCMO system.

Photoluminescence properties of color-tunable SrMgAl10O17:Eu2+,Mn2+ phosphors for UV LEDs

International Nuclear Information System (INIS)

Ju Guifang; Hu Yihua; Chen Li; Wang Xiaojuan

2012-01-01

Aluminate phosphors SrMgAl 10 O 17 codoped with Eu 2+ and Mn 2+ ions were prepared by solid-state reaction. The phase structure and photoluminescence properties of the as-prepared phosphors were characterized by powder X-ray diffraction, photoluminescence excitation and emission spectra. Upon excitation of UV light, two broad emission bands centered at 470 and 515 nm were observed, and they were assigned to Eu 2+ and Mn 2+ emissions, respectively. The emission color of the phosphors can be tuned from blue to cyan and finally to green by adjusting the concentration ratios of Eu 2+ and Mn 2+ . Effective energy transfer occurs from Eu 2+ to Mn 2+ in the host due to the spectral overlap between the emission band of Eu 2+ and the excitation bands of Mn 2+ . The energy transfer mechanism was demonstrated to be electric dipole–quadrupole interaction. The energy transfer efficiency and critical distance were also calculated. The phosphors exhibit strong absorption in near UV spectral region and therefore they are potentially useful as UV-convertible phosphors for white LEDs. - Highlights: ► The strong absorption of phosphors matches well with the emission band of UV LED. ► The energy transfer from Eu 2+ to Mn 2+ in SrMgAl 10 O 17 was investigated in detail. ► The emission color can be tuned by adjusting the content of Eu 2+ and Mn 2+ . ► Two methods were employed to calculate the critical distance of energy transfer.

A new rechargeable lithium-ion battery with a xLi2MnO3.(1 - x) LiMn0.4Ni0.4Co0.2O2 cathode and a hard carbon anode

International Nuclear Information System (INIS)

Liu Jinlong; Wang Jie; Xia Yongyao

2011-01-01

Highlights: → A new type of battery with 0.4Li 2 MnO 3 0.6LiMn 0.4 Ni 0.4 Co 0.2 O 2 and hard carbon was proposed. → The irreversible capacity encountered at both electrodes, can be counterbalanced each other. → The battery delivers capacities of 105 mAh g -1 and specific energies of 315 Wh kg -1 . - Abstract: We reported a new type of rechargeable lithium-ion battery consisting of a structurally integrated 0.4Li 2 MnO 3 .0.6LiMnNi 0.4 Co 0.2 O 2 cathode and a hard carbon anode. The drawback of the high irreversible capacity loss of both electrodes, occurring at the first charge/discharge process, can be counterbalanced each other. The battery shows good reversibility with a sloping voltage from 1.5 V to 4.5 V and delivers a capacity of 105 mA h g -1 and a specific energy of 315 W h kg -1 based on the total weight of the both active electrode materials.

Structural characterization of Mg{sub 3}MnH{sub {approx}}{sub 6}--a new high-pressure phase synthesized in a multi-anvil cell at 6 GPa

Energy Technology Data Exchange (ETDEWEB)

Blomqvist, Helen; Roennebro, Ewa; Kyoi, Daisuke; Sakai, Tetsuo; Noreus, Dag

2003-08-25

With modern X-ray diffraction refinement methods it was shown to be possible to identify a new Mg{sub 3}MnH{sub {approx}}{sub 6} phase from a minute sample volume in spite of poor crystallinity and coexisting impurity phases. The new hydride was synthesized at 6 GPa in a high-pressure multi-anvil cell at 873 K. A monoclinic unit cell was found with a=8.827(2), b=4.657(2), c=4.676(2) A and {beta}=105.74(2) deg., space group P2{sub 1}/m (no. 11), Z=2, V=184.99 A{sup 3}. Manganese is surrounded by a distorted cube of magnesium with average Mn-Mg distances of 2.78(2) A. The cubes share edges in the b and c directions of the unit cell but are separated by a distance of {approx}3.6 A along a, forming a layered structure. The hydrogen positions were not possible to determine, as only a small sample amount could be prepared. If the metal atom structure of the title compound is compared to the already known Mg{sub 3}MnH{sub 7} it can be concluded that Mg{sub 3}MnH{sub {approx}}{sub 6} also consists of manganese hydrido complexes counterbalanced by magnesium ions, but with a different alignment of the magnesium cubes.

Texture and structure contribution to low-temperature plasticity enhancement of Mg-Al-Zn-Mn Alloy MA2-1hp after ECAP and annealing

Science.gov (United States)

Serebryany, V. N.; D'yakonov, G. S.; Kopylov, V. I.; Salishchev, G. A.; Dobatkin, S. V.

2013-05-01

Equal channel angular pressing (ECAP) in magnesium alloys due to severe plastic shear deformations provides both grain refinement and the slope of the initial basal texture at 40°-50° to the pressing direction. These changes in microstructure and texture contribute to the improvement of low-temperature plasticity of the alloys. Quantitative texture X-ray diffraction analysis and diffraction of backscattered electrons are used to study the main textural and structural factors responsible for enhanced low-temperature plasticity based on the example of magnesium alloy MA2-1hp of the Mg-Al-Zn-Mn system. The possible mechanisms of deformation that lead to this positive effect are discussed.

Mechanical Properties and Microstructure of TIG and FSW Joints of a New Al-Mg-Mn-Sc-Zr Alloy

Science.gov (United States)

Xu, Guofu; Qian, Jian; Xiao, Dan; Deng, Ying; Lu, Liying; Yin, Zhimin

2016-04-01

A new Al-5.8%Mg-0.4%Mn-0.25%Sc-0.10%Zr (wt.%) alloy was successfully welded by tungsten inert gas (TIG) and friction stir welding (FSW) techniques, respectively. The mechanical properties and microstructure of the welded joints were investigated by microhardness measurements, tensile tests, and microscopy methods. The results show that the ultimate tensile strength, yield strength, and elongation to failure are 358, 234 MPa, and 27.6% for TIG welded joint, and 376, 245 MPa and 31.9% for FSW joint, respectively, showing high strength and superior ductility. The TIG welded joint fails in the heat-affected zone and the fracture of FSW joint is located in stirred zone. Al-Mg-Mn-Sc-Zr alloy is characterized by lots of dislocation tangles and secondary coherent Al3(Sc,Zr) particles. The superior mechanical properties of the TIG and FSW joints are mainly derived from the Orowan strengthening and grain boundary strengthening caused by secondary coherent Al3(Sc,Zr) nano-particles (20-40 nm). For new Al-Mg-Mn-Sc-Zr alloy, the positive effect from secondary Al3(Sc, Zr) particles in the base metal can be better preserved in FSW joint than in TIG welded joint.

Study of some Mg-based ferrites as humidity sensors

International Nuclear Information System (INIS)

Rezlescu, N; Rezlescu, E; Doroftei, C; Popa, P D

2005-01-01

The micostructure and humidity sensitivity of MgFe 2 O 4 + CaO, Mg 0.5 Cu 0.5 Fe 1.8 Ga 0.2 O 4 , Mg 0.5 Zn 0.5 Fe 2 O 4 + KCl and MgMn 0.2 Fe 1.8 O 4 ferrites were investigated. We have found that the humidity sensitivity largely depends on composition, crystallite size, surface area and porosity. The best results concerning humidity sensitivity were obtained for MgMn 0.2 Fe 1.8 O 4 ferrite

Effect of Mg addition on LaMnO3 ceramic system

Directory of Open Access Journals (Sweden)

García Iván Supelano

2018-01-01

Full Text Available In the present work we report the synthesis of La1−xMgxMnO3 (with x = 0.10, 0.25, and 0.50 polycrystalline samples based on LaMnO3 (LMO antiferromagnetic with low Neel temperature and insulating behavior. Structure was analyzed by Rietveld fitting of XRD patterns at room temperature by FullProf software, these show that La1−xMgxMnO3 (x = 0.10, 0.25, 0.50 samples crystallize in the space group R-3c. Magnetic and electrical measurements exhibits ferromagnetic and semiconductor like behavior. A decreases of TC is observed when x doping value increases.

Solubility limits in Mn–Mg ferrites system under hydrothermal conditions

Energy Technology Data Exchange (ETDEWEB)

Hemeda, O.M., E-mail: omhemeda@yahoo.co.uk [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt); Mostafa, N.Y. [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt); Faculty of Science, Taif University, PO Box 888, Al-Haweiah, Taif (Saudi Arabia); Abd Elkader, O.H. [Electron Microscope and Thin Films Department, National Research Center, Dokki 12622, Cairo (Egypt); Electron Microscope Unit, Zoology Department, King Saud University, Riyadh 11451 (Saudi Arabia); Ahmed, M.A. [Physics Department, Faculty of Science, Al Azhar University, Nasr City, Cairo (Egypt)

2014-09-01

In the present investigation, we successfully synthesized a pure MnFe{sub 2}O{sub 4} ferrite by the hydrothermal method. Moreover, the effect of Mg ion content on the formation of Mn{sub 1−x}Mg{sub x}Fe{sub 2}O{sub 4} particles (with x varying from 0.1 to 1.0) was also investigated using XRD, SEM, TEM and Mossbauer Spectroscopy. Phases formed in the system Mn{sub 1−x}Mg{sub x}Fe{sub 2}O{sub 4}; 0.0≤x≤1.0 were investigated under hydrothermal conditions at 453 K.The produced phases were characterized by X-ray diffraction, Scanning, transmission microscopy and Mossbauer spectroscopy. The information of composition, cation distribution in the spinel structure and the particle size of the products were obtained. The spinel ferrites; Mn{sub 1−x}Mg{sub x}Fe{sub 2}O{sub 4} were formed in the range 0.0≤x≤0.3. However, sample with x>0.3 showed semi-crystalline magnesium hydroxide (Mg(OH){sub 2}) and hematite (Fe{sub 2}O{sub 3}) beside the ferrite phase. For x=1.0, only magnesium hydroxide and hematite are formed without any ferrites. Particles of uniform size around 10–20 nm were obtained in the spinel structure of Mn{sub 1−x}Mg{sub x}Fe{sub 2}O{sub 4} with x=0.0 and 0.1. The corresponding average crystallite size for each sample was 40.3 nm and 39.2 nm respectively. In addition, the Mossbauer spectra were analyzed into two subspectra, one for the tetrahedral A-site and the other for the octahedral B-site. The Mossbauer parameters were determined and discussed for the studied system. The cation distribution was estimated from the analysis of the Mossbauer spectra as well as the X-ray diffraction patterns. The results showed that Mg ions occupy mainly B-site while both Mn and Fe ions are distributed between A- and B-sites. - Highlights: • Mossbauer characterization of Mg–Mn ferrite prepared by hydrothermal route. • X-ray powder diffraction analysis of Mg–Mn ferrite prepared by hydrothermal route. • Solubility limit of MgMn ferrite under

Oxygen redox chemistry without excess alkali-metal ions in Na2/3[Mg0.28Mn0.72]O2.

Science.gov (United States)

Maitra, Urmimala; House, Robert A; Somerville, James W; Tapia-Ruiz, Nuria; Lozano, Juan G; Guerrini, Niccoló; Hao, Rong; Luo, Kun; Jin, Liyu; Pérez-Osorio, Miguel A; Massel, Felix; Pickup, David M; Ramos, Silvia; Lu, Xingye; McNally, Daniel E; Chadwick, Alan V; Giustino, Feliciano; Schmitt, Thorsten; Duda, Laurent C; Roberts, Matthew R; Bruce, Peter G

2018-03-01

The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds as promising high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion and charge compensation by transition-metal (TM) ions. The additional capacity is provided through charge compensation by oxygen redox chemistry and some oxygen loss. It has been reported previously that oxygen redox occurs in O 2p orbitals that interact with alkali ions in the TM and alkali-ion layers (that is, oxygen redox occurs in compounds containing Li + -O(2p)-Li + interactions). Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 exhibits an excess capacity and here we show that this is caused by oxygen redox, even though Mg 2+ resides in the TM layers rather than alkali-metal (AM) ions, which demonstrates that excess AM ions are not required to activate oxygen redox. We also show that, unlike the alkali-rich compounds, Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 does not lose oxygen. The extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen, which promotes oxygen loss, whereas Mg 2+ remains in Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 , which stabilizes oxygen.

Effect of Pre-Aging Conditions on Bake-Hardening Response of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn Alloy Sheets

International Nuclear Information System (INIS)

Lee, Kwang-jin; Woo, Kee-do

2011-01-01

Pre-aging heat treatment after solution heat treatment (SHT) of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn alloy sheets for auto-bodies was carried out to investigate the effect of pre-aging and its conditions on the bake-hardening response. Mechanical properties were evaluated by a tensile and Vickers hardness test. Microstructural observation was also performed using a transmission electron microscope (TEM). It was revealed that pre-aging treatments play a great role in the bake-hardening response. In addition, it was found that the sphere-shaped nanosized clusters that can directly transit to the needle-shaped β” phase during the paint-bake process, not being dissolved into the matrix, are formed at 343 K. The result, reveals that the dominant factor of the bake-hardening response is the pre-aging temperature rather than the pre-aging time.

Magnetic Properties and Magnetocaloric Effect in Layered NdMn1.9Ti0.1Si2

Directory of Open Access Journals (Sweden)

M.F. Md Din

2014-04-01

Full Text Available The structural and magnetic properties of the NdMn1.9Ti0.1Si2 compund have been studied by high-intensity x-ray and high-resolution neutron powder diffraction, specific heat, dc magnetization, and differential scanning calorimetry measurements over the temperature range of 3-450 K. The Curie temperature and Néel temperature of layered NdMn1.9Ti0.1Si2 are indicated as TC ~ 22 K and TN ~ 374 K respectively. The first order magnetic transition from antiferromagnetic [AFil-type] to ferromagnetic [F(Nd+Fmc] around TC is found in layered NdMn1.9Ti0.1Si2 and is associated with large magnetocaloric effect. This behavior has been confirmed as a contribution of the magnetostructural coupling by using neutron and x-ray powder diffraction. The magnetic entropy change –ΔSM ~ 15.3 J kg-1 K-1 and adiabatic temperature change ΔTad ~ 4.7 K have been determined using magnetization and specific heat measurement under 0-5 T applied fields. This compound exhibits almost no thermal and magnetic hysteresis, thus potentially applicable in low temperature region for magnetic refrigerator material

Magnetic phase transitions and magnetocaloric effect of MnCoGe{sub 1−x}Si{sub x}

Energy Technology Data Exchange (ETDEWEB)

Lai, J.W.; Zheng, Z.G.; Montemayor, R.; Zhong, X.C.; Liu, Z.W.; Zeng, D.C., E-mail: medczeng@scut.edu.cn

2014-12-15

Here a cheaper alternative magnetic refrigeration material using MnCoGe{sub 1−x}Si{sub x} (x=0, 0.1, 0.3, and 0.5) alloys were investigated. The polycrystalline MnCoGe{sub 1−x}Si{sub x} alloys were prepared by arc-melting followed by annealing at 1123 K for 72 h. At a 0.5 at% Si substitution, the Curie temperatures increased by 10% to 374 K, the magnetic entropy change (|ΔS{sub M}|) values decreased by 32% to 2.1 J kg{sup −1} K{sup −1} in an applied field from 0 to 2 T and by 24% to 4.4 J kg{sup −1} K{sup −1} in an applied field from 0 to 5 T. However, the refrigeration capacity (RC{sub FWHM}) of this MnCoGe{sub 0.5}Si{sub 0.5} alloy improved by 27% to 282 J kg{sup −1} and the operation temperature range (δT{sub FWHM}) improved by 92% to 96 K in an applied field at 5 T. The MnCoGe{sub 0.5}Si{sub 0.5} alloy can compete with some of the MCE properties of the MnCo{sub 0.95}Ni{sub 0.05}Ge, LaFe{sub 11}Al{sub 2}C{sub 0.5}, (Fe{sub 85}Co{sub 5}Cr{sub 10}){sub 91}Zr{sub 7}B{sub 2}, and even the Gd{sub 5}Si{sub 2}Ge{sub 2} alloys. The broad operation temperature range (96 K) at a higher Curie temperature (374 K) suggests that the MnCoGe{sub 0.5}Si{sub 0.5} alloy can become a cheaper alternative MCE material (costing 70% less than a MnCoGe alloy). - Highlights: • The economic Si substitutes the noble metal Ge and broadens temperature span(96 K). • The T{sub C} arises when increasing Si in higher room temperature range, 340–374 K. • High thermal stability make them attractive for service temperature of above 300 K. • When Si increases, ΔS{sub M} decreases slightly due to the spontaneous magnetization M{sub S}. • The superior refrigerant capacity indicates that Si substitution benefits the MCE.

⁵³Mn-⁵³Cr and ²⁶Al-²⁶Mg ages of a feldspathic lithology in polymict ureilites

Energy Technology Data Exchange (ETDEWEB)

Goodrich, Cyrena Anne [Planetary Science Institute. Tucson, AZ (United States); Hutcheon, Ian D. [Glenn T. Seaborg Institute. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kita, Noriko T. [Dept. of Geoscience. Univ. of Wisconsin, Madison, WI (United States); Huss, Gary R. [NASA Marshall Space Flight Center (MSFC), Huntsville, AL (United States); Cohen, Barbara Anne [Hawaii Institute of Geophysics and Planetology. Univ. of Hawaii, Honolulu, HI (United States); Keil, Klaus

2010-07-01

We report ⁵³Mn–⁵³Cr and ²⁶Al–²⁶Mg isotopic data, obtained by in-situ SIMS analysis, for feldspathic clasts in polymict ureilites DaG 319 and DaG 165. The analyzed clasts belong to the “albitic lithology,” the most abundant population of indigenous feldspathic materials in polymict ureilites, and are highly fractionated igneous assemblages of albitic plagioclase, Fe-rich pyroxenes, phosphates, ilmenite, silica, and Fe(Mn, K, P, Ti)-enriched glass. Glass in DaG 165 clast 19 has extremely high and variable ⁵⁵Mn/⁵²Cr ratios (500–58,000) and shows correlated ⁵³Cr excesses up to ~ 1500‰, clearly indicating the presence of live ⁵³Mn at the time of formation. The slope of the well-correlated isochron defined by glass and pyroxenes from this clast corresponds to (⁵³Mn/⁵⁵Mn) = (2.84 ± 0.10) × 10^-6 (2σ). Data for less ⁵⁵Mn/⁵²Cr-enriched glasses from DaG 319 clast B1, as well as phosphates from several other clasts, are consistent with this isochron. The ⁵³Mn/⁵⁵Mn ratio obtained from the isochron implies that these clasts are 0.70 ± 0.18 Ma younger than the D'Orbigny angrite, corresponding to the absolute age of 4563.72 ± 0.22 Ma. Plagioclase in DaG 319 clast B1 has a fairly constant ²⁷Al/²⁴Mg ratio of ~ 900 and shows resolvable ²⁶Mg excesses of ~ 2‰. The slope of the isochron defined by pyroxene and plagioclase in this clast is (3.0 ± 1.1) × 10^-7 (2σ), corresponding to a time difference of 5.4 (-0.3/+0.5) Ma after CAI (assuming the canonical initial ²⁶Al/²⁷Al ratio of 5 × 10^-5) and an age 0.5 (-0.3/+0.5) Ma younger than D'Orbigny. Its absolute age (relative to D'Orbigny) is 4563.9 (+ 0.4/-0.5) Ma, in agreement with the ⁵³Mn–⁵³Cr age from clast 19. These data provide the first

Regularities in structure formation of magnesium-yttrium alloy of Mg-Y-Mn-Cd system in relation to temperature and hot working rate

International Nuclear Information System (INIS)

Ovechkin, B.I.; Miklina, N.V.; Blokhin, N.N.; Sorokin, A.F.

1981-01-01

Problems of the structure formation of magnesium-yttrium alloy of Mg-G-Mn-Cd system with 7.8 % G in a wide range of temperature-rate parameters of hot working are studied. On the basis of X-ray analysis results ascertained with metallographic and electron microscopic investigations, a diagram of structural states after hot working of Mg-G-Mn-Cd system alloy has been plotted. A change in grain size in relation to temperature-rate conditions of hot working

Enhancement of electrochemical performance of LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 by surface modification with MnO_2

International Nuclear Information System (INIS)

Guo, Xin; Cong, Li-Na; Zhao, Qin; Tai, Ling-Hua; Wu, Xing-Long; Zhang, Jing-Ping; Wang, Rong-Shun; Xie, Hai-Ming; Sun, Li-Qun

2015-01-01

LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 is successfully coated with MnO_2 by a chemical deposition method. The X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) results demonstrate that MnO_2 forms a thin layer on the surface of LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 without destroying the crystal structure of the core material. Compared with pristine LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2, the MnO_2-coated sample shows enhanced electrochemical performance especially the rate capability. Even at a current density of 750 mA g"−"1, the discharge capacity of MnO_2-coated LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 is 155.15 mAh g"−"1, while that of the pristine electrode is only 132.84 mAh g"−"1 in the range of 2.5–4.5 V. The cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) curves show that the MnO_2 coating layer reacts with Li"+ during cycling, which is responsible for the higher discharge capacity of MnO_2-coated LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2. Electrochemical impedance spectroscopy (EIS) results confirmed that the MnO_2 coating layer plays an important role in reducing the charge transfer resistance on the electrolyte–electrode interfaces. - Highlights: • MnO_2 coated LiNi_1_/_3Co_1_/_3Mn_1_/_3O_2 cathode material is synthesized for the first time. • MnO_2 offers available sites for insertion of extracted lithium. • The preserved surface and crystal structures results in the improved kinetics.

Deformation behavior of commercial Mg-Al-Zn-Mn type alloys under a hydrostatic extrusion process at elevated temperatures

International Nuclear Information System (INIS)

Yoon, Duk Jae; Lee, Sang Mok; Lim, Seong Joo; Kim, Eung Zu

2010-01-01

This paper presents the deformation behavior of commercial Mg-Al-Zn-Mn type alloys during hydrostatic extrusion process at elevated temperatures. In the current study commercial Mg-Al-Zn-Mn type alloys with different Al contents were subjected to hydrostatic extrusion process at a range of temperatures and at ram speeds of 4.5, 10 and 17 mm/sec. Under the hydrostatic condition at 518K, the alloy with Al contents of 2.9 wt% was successfully extruded at all applied speeds. The alloys with Al content of 5.89 and 7.86 wt% were successful up to 10mm/sec, and finally extrusion of alloy with Al content 8.46wt% was successful only at 4.5 mm/sec. These results show that the deformation limit in the Mg alloys in terms of extrusion speed greatly extended to higher value in the proximity of lower Al content. It is presumed that deformation becomes harder as Al content increases because of strengthening mechanism by solute drag to increase of supersaturated Mg 17 Al 12 precipitates. Also, microstructures of cast and extruded Mg alloys were compared. Defect-wide microstructure of cast alloy completely evolved into dense and homogeneous microstructure with equiaxed grains

Bimetallic Co-Mn Perovskite Fluorides as Highly-Stable Electrode Materials for Supercapacitors.

Science.gov (United States)

Shi, Wei; Ding, Rui; Li, Xudong; Xu, Qilei; Ying, Danfeng; Huang, Yongfa; Liu, Enhui

2017-11-02

Bimetallic Co-Mn perovskite fluorides (KCo x Mn 1-x F 3 , denoted as K-Co-Mn-F) with various Co/Mn ratios (1:0, 12:1, 6:1, 3:1, 1:1, 1:3, 0:1) were prepared through a one-pot solvothermal strategy and further used as electrode materials for supercapacitors. The optimal K-Co-Mn-F candidate (Co/Mn=6:1) showed a size range of 0.1-1 μm and uniform elemental distribution; exhibiting small changes in XRD peaks and XPS binding energy in comparison to the bare K-Co-F and K-Mn-F, due to the structural/electronic effects. Owing to the stronger synergistic effect of Co/Mn redox species, the K-Co-Mn-F (Co/Mn=6:1) electrode exhibited superior specific capacity and rate behavior (113-100 C g -1 at 1-16 Ag -1 ) together with excellent cycling stability (118 % for 5000 cycles at 8 Ag -1 ), and the activated carbon (AC)//K-Co-Mn-F (Co/Mn=6:1) asymmetric capacitor showed superior energy and power densities (8.0-2.4 Wh kg -1 at 0.14-8.7 kW kg -1 ) along with high cycling stability (90 % for 10 000 cycles at 5 Ag -1 ). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of organometallic chelates and inulin in diets for laying hens on Mn and Fe absorption coefficients and their content in egg and tissue

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Cornescu Gabriela Maria

2015-01-01

Full Text Available The aim of this study was to evaluate effects of organic sources of manganese (Mn and iron (Fe and inulin in diets for laying hens on absorption of these minerals and their deposition in egg and tissue. The study was conducted on 90 Lohmann Brown laying hens in the period from 46-52 weeks of age, assigned to 3 groups with 30 hens/group and 3 hens/cage. The hens from the control group (C received a diet based on corn, rice bran and soybean meal with 16% of crude protein, as well as 60 mg Fe/kg and 71.9 mg Mn/kg of diet in form of inorganic salts. The formulation of the experimental diets (E1 and E2 differed from C group diet by the replacement of inorganic Fe and Mn salts by organometallic chelates of these elements, at a level of 25% lower than in the premix for group C. As source of inulin, group E1 diet also included 0.5% of dry Jerusalem artichoke, while group E2 diet included 0.5% of a product based on chicory root extract. At the end of the experiment, 6 hens from each group were slaughtered and blood serum and liver samples were collected and assayed for concentration of Fe and Mn. In the final week of the experiment, 18 eggs/group were collected for determination of Fe and Mn concentration in egg yolk. Concentration of measured blood serum parameters (haemoglobin, haematocrit, Fe and Mn in experimental (E groups were lower than in group C, but no significant differences (P>0.05 were registered. Absorption coefficients of Mn had higher values in E groups than in group C, with significant increase (P0.05 between groups were observed for Mn and Fe concentration in egg yolk.

Discharge capacity and microstructures of La Mg Pr Al Mn Co Ni alloys for nickel-metal hydride batteries

International Nuclear Information System (INIS)

Casini, J.C.S.; Galdino, G.S.; Ferreira, E.A.; Takiishi, H.; Faria, R.N.

2010-01-01

La 0.7-x Mg x Pr 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 (x = 0.0, 0.3 and 0.7) alloys have been investigated aiming the production of negative electrodes for nickel-metal hydride batteries. The alloys employed in this work were used in the as cast state. The results showed that the substitution of magnesium by lanthanum increased the discharge capacity of the Ni-MH batteries. A battery produced with the La 0.4 Mg 0.3 Pr 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy shown a high discharge capacity (380mAh/g) also good stability compared to other alloys. The electrode materials were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). (author)

Multilevel Resistance Switching Memory in La2/3Ba1/3MnO3/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (011) Heterostructure by Combined Straintronics-Spintronics.

Science.gov (United States)

Zhou, Weiping; Xiong, Yuanqiang; Zhang, Zhengming; Wang, Dunhui; Tan, Weishi; Cao, Qingqi; Qian, Zhenghong; Du, Youwei

2016-03-02

We demonstrate a memory device with multifield switchable multilevel states at room temperature based on the integration of straintronics and spintronics in a La2/3Ba1/3MnO3/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) (011) heterostructure. By precisely controlling the electric field applied on the PMN-PT substrate, multiple nonvolatile resistance states can be generated in La2/3Ba1/3MnO3 films, which can be ascribed to the strain-modulated metal-insulator transition and phase separation of Manganite. Furthermore, because of the strong coupling between spin and charge degrees of freedom, the resistance of the La2/3Ba1/3MnO3 film can be readily modulated by magnetic field over a broad temperature range. Therefore, by combining electroresistance and magnetoresistance effects, multilevel resistance states with excellent retention and endurance properties can be achieved at room temperature with the coactions of electric and magnetic fields. The incorporation of ferroelastic strain and magnetic and resistive properties in memory cells suggests a promising approach for multistate, high-density, and low-power consumption electronic memory devices.

CALPHAD simulation of the Mg–(Mn, Zr)–Fe system and experimental comparison with as-cast alloy microstructures as relevant to impurity driven corrosion of Mg-alloys

Energy Technology Data Exchange (ETDEWEB)

Gandel, D.S., E-mail: darren.gandel@monash.edu [CAST Cooperative Research Centre (Australia); Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia); Easton, M.A. [CAST Cooperative Research Centre (Australia); Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia); Gibson, M.A. [CAST Cooperative Research Centre (Australia); CSIRO Process Science and Engineering, Clayton, VIC 3168 (Australia); Birbilis, N. [CAST Cooperative Research Centre (Australia); Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia)

2014-02-14

Four Mg alloys with variations in the ratio of Mn, Zr and Fe additions were cast and their microstructures analysed via electron microscopy. Thermodynamic calculations of the expected phases using PANDAT were evaluated with actual as-cast microstructures. Some of the as-cast alloys did appear to form phases similar to those anticipated from the PANDAT calculations. Furthermore, there was a new Mn–Fe particle interaction observed that was not predicted, but which is posited to be responsible for the increase in corrosion resistance among Mn containing Mg alloys with Fe impurities. The experimental work herein has been shown to be invaluable in the understanding of this practically important system with sparingly soluble Fe and its potential influence on the corrosion of Mg alloys. - Highlights: • Alloy microstructure of the Mg-(Mn,Zr, Fe) system was analysed and reported. • CALPHAD analysis was used in conjunction with traditional SEM analysis techniques in this study. • A proposed Mn–Fe interaction within Mg has been observed for the first time. • Experimental validation of calculated phases is required to understand the effect of Mn and Zr on Mg.

Cafeína (150 mg/kg y aprendizaje espacial (retención y adquisición en ratones

Directory of Open Access Journals (Sweden)

María del Pilar Santacruz

2003-01-01

Full Text Available En este trabajo se evaluó el papel que juega la cafeína (150mg/kg en el aprendizaje espacial (adquisición y retención en ratones mediante las mediciones de la latencia de salida, velocidad, aciertos, regresos, errores y excretas en un laberinto de 3 x 3 metros. Los sujetos fueron moldeados para una ruta en el laberinto y luego se aleatorizaron 20 machos y 20 hembras para la administración de cafeína (s.c. y solución salina durante ocho días consecutivos; luego se observó la retención de este aprendizaje y se moldeó otra ruta para evaluar su retención 24 horas después: La cafeína incrementó la retención del aprendizaje 1, donde hubo los mayores aciertos, y en el segundo las hembras con cafeína exhibieron mayor velocidad y aciertos mientras que los machos, presentaron menores aciertos y velocidad que todos los grupos; como vemos, en el segundo caso, la cafeína fortaleció la retención del aprendizaje 2 en las hembras y la debilitó en los machos. Se concluye que la cafeína (150mg/kg influyó positivamente en la retención del aprendizaje espacial, mas no en la adquisición. Este artículo está asociado a la línea de investigación en Cafeína y Cognición de la Universidad de la Sabana.

Catalytic activity of bimetallic AuPd alloys supported MgO and MnO2 nanostructures and their role in selective aerobic oxidation of alcohols

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Hamed Alshammari

2017-10-01

Full Text Available The use of metal oxides as supports for gold and palladium (Au-Pd nano alloys constitutes new horizons to improve catalysts materials for very important reactions. From the literatures, Pd-based bimetallic nanostructures have great properties and active catalytic performance. In this study, nanostructures of magnesium oxide (MgO and manganese dioxide (MnO₂ were synthesised and utilized as supports for Au-Pd nanoparticle catalysts. Gold and palladium were deposited on these supports using sol-immobilisation method. The MgO and MnO2 supported Au-Pd catalysts were evaluated for the oxidation of benzyl alcohol and 1-octanol, respectively. These catalysts were found to be more selective, active and reusable than the corresponding monometallic Au and Pd catalysts. The effect of base supports on the disproportionation reaction during the oxidation process was investigated. The results show that MgO stopped the disproportionation reaction for both aromatic and aliphatic alcohols while MnO₂ stopped it in the case of benzyl alcohol only. The outcomes of this work shed light on the selective aerobic oxidation of alcohols using bimetallic Au-Pd nanoalloys and pave the way to a complete investigation of more basic metal oxides for various aliphatic alcohols.

[Emission spectrum temperature sensitivity of Mg4FGeO6 : mn induced by laser].

Science.gov (United States)

Wang, Sheng; Liu, Jing-Ru; Shao, Jun; Hu, Zhi-Yun; Tao, Bo; Huang, Mei-Sheng

2013-08-01

In order to develop a new sort of thermally sensitive phosphor coating, the emission spectrum thermally sensitivity of Mg4FGeO6 : Mn induced by laser was studied. The spectrum measurement system with heating function was set up, and the emission spectrum of Mg4FGeO6 : Mn at various temperatures were measured. Absorption spectrum was measured, and the mechanism of formation of the structure of double peak was analyzed with the perturbation theory of crystal lattice. The group of peaks around 630 nm is represented by the transitions 4F"2 to 4A2, whereas the group of peaks around 660 nm is due to the transitions 4F'2 to 4A2. The occupancy of both excited states 4F'2 and 4F"2 is in thermal equilibrium. Thus increasing temperature causes the intensity of the emission in the group around 630 nm to increase at the expense of the emission intensity of the group around 660 nm. The various spectral regions in emission differ with temperature, which could be used to support the intensity-ratio measurement method. The intensity-ratio change curve as a function of temperature was fitted, which shows that the range of temperature measurement is between room temperature and 800 K.

The influence of some additives to the highly carbohydrate diet on the distribution of Al, Ca, Mg, Mn and Na in teeth enamel and bones of experimental animals

International Nuclear Information System (INIS)

Bakyrdzhiev, P.

1985-01-01

An instrument neutron activation analysis had been used for the investigation of diets with different salt and permanent basic composition. The diets with MgCl 2 and methylene blue additives were used. Three groups of animals Wistar, Hamster and S. Dawley with different genetic reactivity had been fed on adlibidum for 45 days. After killing the animals the teeth enamel, mandibula and tibia had been sampled and content of Al, Mg, Mn, Na and Cl 2 was determined by means of INAA. The samples were irradiated for 1 min in the rabbit system of the experimental reactor IRT-2000. Two measurements were carried out - after a cooling time of 1 min for the determination of Al, Ca, Cl 2 , Mg, and after 2 h cooling time - for Na and Mn. The precision of the analysis was between 4 and 12%

Isopiestic Investigation of the Osmotic and Activity Coefficients of {yMgCl2 + (1 - y)MgSO4}(aq) and the Osmotic Coefficients of Na2SO4.MgSO4(aq) at 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Miladinovic, J; Ninkovic, R; Todorovic, M; Rard, J A

2007-06-06

Isopiestic vapor pressure measurements were made for {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) solutions with MgCl{sub 2} ionic strength fractions of y = 0, 0.1997, 0.3989, 0.5992, 0.8008, and (1) at the temperature 298.15 K, using KCl(aq) as the reference standard. These measurements for the mixtures cover the ionic strength range I = 0.9794 to 9.4318 mol {center_dot} kg{sup -1}. In addition, isopiestic measurements were made with NaCl(aq) as reference standard for mixtures of {l_brace}xNa{sub 2}SO{sub 4} + (1-x)MgSO{sub 4}{r_brace}(aq) with the molality fraction x = 0.50000 that correspond to solutions of the evaporite mineral bloedite (astrakanite), Na{sub 2}Mg(SO{sub 4}){sub 2} {center_dot} 4H{sub 2}O(cr). The total molalities, m{sub T} = m(Na{sub 2}SO{sub 4}) + m(MgSO{sub 4}), range from m{sub T} = 1.4479 to 4.4312 mol {center_dot} kg{sup -1} (I = 5.0677 to 15.509 mol {center_dot} kg{sup -1}), where the uppermost concentration is the highest oversaturation molality that could be achieved by isothermal evaporation of the solvent at 298.15 K. The parameters of an extended ion-interaction (Pitzer) model for MgCl2(aq) at 298.15 K, which were required for an analysis of the {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) mixture results, were evaluated up to I = 12.025 mol {center_dot} kg{sup -1} from published isopiestic data together with the six new osmotic coefficients obtained in this study. Osmotic coefficients of {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) solutions from the present study, along with critically-assessed values from previous studies, were used to evaluate the mixing parameters of the extended ion-interaction model.

Suppression of superconductivity in Nb by IrMn in IrMn/Nb bilayers

KAUST Repository

Wu, B. L.

2013-10-10

Effect of antiferromagnet on superconductivity has been investigated in IrMn/Nb bilayers. Significant suppression of both transition temperature (Tc) and lower critical field (Hc1) of Nb is found in IrMn/Nb bilayers as compared to a single layer Nb of same thickness; the suppression effect is even stronger than that of a ferromagnet in NiFe/Nb bilayers. The addition of an insulating MgO layer at the IrMn-Nb interface nearly restores Tc to that of the single layer Nb, but Hc1 still remains suppressed. These results suggest that, in addition to proximity effect and magnetic impurity scattering, magnetostatic interaction also plays a role in suppressing superconductivity of Nb in IrMn/Nb bilayers. In addition to reduced Tc and Hc1, the IrMn layer also induces broadening in the transition temperature of Nb, which can be accounted for by a finite distribution of stray field from IrMn.

Five-year field results and long-term effectiveness of 20 mg/kg liposomal amphotericin B (Ambisome for visceral leishmaniasis in Bihar, India.

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Sakib Burza

Full Text Available BACKGROUND: Visceral Leishmaniasis (VL; also known as Kala-azar is an ultimately fatal disease endemic in Bihar. A 2007 observational cohort study in Bihar of 251 patients with VL treated with 20 mg/Kg intravenous liposomal amphotericin B (Ambisome demonstrated a 98% cure rate at 6-months. Between July 2007 and August 2012, Médecins Sans Frontières (MSF and the Rajendra Memorial Research Institute (RMRI implemented a VL treatment project in Bihar, India-an area highly endemic for Leishmania donovani-using this regimen as first-line treatment. METHODS AND PRINCIPAL FINDINGS: Intravenous Ambisome 20 mg/kg was administered in four doses of 5 mg/kg over 4-10 days, depending on the severity of disease. Initial clinical cure at discharge was defined as improved symptoms, cessation of fever, and recession of spleen enlargement. This observational retrospective cohort study describes 8749 patients with laboratory-confirmed primary VL treated over a 5-year period: 1396 at primary healthcare centers, 7189 at hospital, and 164 at treatment camps. Initial clinical cure was achieved in 99.3% of patients (8692/8749; 0.3% of patients (26/8749 defaulted from treatment and 0.4% (31/8749 died. Overall, 1.8% of patients (161/8749 were co-infected with HIV and 0.6% (51/8749 with tuberculosis. Treatment was discontinued because of severe allergic reactions in 0.1% of patients (7/8749. Overall, 27 patients (0.3% were readmitted with post Kala-azar dermal leishmaniasis (PKDL. Risk factors for late presentation included female sex, age >15 years and being from a scheduled caste. In 2012, a long-term efficacy survey in the same area of Bihar determined relapse rates of VL after 5 years' intervention with Ambisome. Of 984 immunocompetent patients discharged between September 2010 and December 2011, 827 (84.0% were traced in order to determine their long-term outcomes. Of these, 20 patients (2.4% had relapsed or received further treatment for VL. Of those completing 6

Mn porphyrin-based SOD mimic, MnTnHex-2-PyP(5+), and non-SOD mimic, MnTBAP(3-), suppressed rat spinal cord ischemia/reperfusion injury via NF-κB pathways.

Science.gov (United States)

Celic, T; Španjol, J; Bobinac, M; Tovmasyan, A; Vukelic, I; Reboucas, J S; Batinic-Haberle, I; Bobinac, D

2014-12-01

Herein we have demonstrated that both superoxide dismutase (SOD) mimic, cationic Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)), and non-SOD mimic, anionic Mn(III) meso-tetrakis(4-carboxylatophenyl)porphyrin (MnTBAP(3-)), protect against oxidative stress caused by spinal cord ischemia/reperfusion via suppression of nuclear factor kappa B (NF-κB) pro-inflammatory pathways. Earlier reports showed that Mn(III) N-alkylpyridylporphyrins were able to prevent the DNA binding of NF-κB in an aqueous system, whereas MnTBAP(3-) was not. Here, for the first time, in a complex in vivo system-animal model of spinal cord injury-a similar impact of MnTBAP(3-), at a dose identical to that of MnTnHex-2-PyP(5+), was demonstrated in NF-κB downregulation. Rats were treated subcutaneously at 1.5 mg/kg starting at 30 min before ischemia/reperfusion, and then every 12 h afterward for either 48 h or 7 days. The anti-inflammatory effects of both Mn porphyrins (MnPs) were demonstrated in the spinal cord tissue at both 48 h and 7 days. The downregulation of NF-κB, a major pro-inflammatory signaling protein regulating astrocyte activation, was detected and found to correlate well with the suppression of astrogliosis (as glial fibrillary acidic protein) by both MnPs. The markers of oxidative stress, lipid peroxidation and protein carbonyl formation, were significantly reduced by MnPs. The favorable impact of both MnPs on motor neurons (Tarlov score and inclined plane test) was assessed. No major changes in glutathione peroxidase- and SOD-like activities were demonstrated, which implies that none of the MnPs acted as SOD mimic. Increasing amount of data on the reactivity of MnTBAP(3-) with reactive nitrogen species (RNS) (.NO/HNO/ONOO(-)) suggests that RNS/MnTBAP(3-)-driven modification of NF-κB protein cysteines may be involved in its therapeutic effects. This differs from the therapeutic efficacy of MnTnHex-2-PyP(5+) which presumably occurs via reactive

Influence of Pr in the microstructure and electrical properties in LaPrMgAlMnCoNi based alloys for using for Ni-MH batteries

International Nuclear Information System (INIS)

Galdino, Gabriel Souza

2011-01-01

The La 0.7-x Pr x Mg 0.3 Al 0.3 Mn- 0.4 Co 0.5 Ni 3.8 (x= 0 a 0.7) as-cast alloys to apply in negative electrodes for nickel-metal hydride batteries (Ni-MH). The characterizations of the alloys were realized by: scanning electron microscope (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction techniques. A study of hydrogen absorption capacity of the alloys realized. The hydrogenation of the material was performed in two processes: the low pressure (0.2 MPa of hydrogen and temperature of the 773 K) and high pressure (1 MPa of hydrogen and temperature of the 298 K). It was observed that with increasing Pr content occurred a decrease the hydrogen absorption capacity. The capacity of discharge of the batteries was determined utilizing an analyzer digital computerized composed of four channels. It was observed decreases of the discharge capacity of the batteries when increase praseodymium content in La 0.7- x Pr x Mg 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni-3 .8 (x= 0 a 0.3) alloys. The highest discharge capacity (386 mAhg -1 ) and stability cyclic were obtained to La 0.2 Pr 0.5 Mg 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy. This capacity can be related to the higher proportion of phase LaMg 2 Ni 9 in the alloy with the addition of 0.5 at.% Pr. (author)

Magnetic-entropy change in Mn1.1Fe0.9P0.7As0.3-xGe x

International Nuclear Information System (INIS)

Tegus, O.; Fuquan, B.; Dagula, W.; Zhang, L.; Brueck, E.; Si, P.Z.; Boer, F.R. de; Buschow, K.H.J.

2005-01-01

We have studied the magnetic properties and magnetic-entropy changes of Mn 1.1 Fe 0.9 P 0.7 As 0.3-x Ge x compounds with x = 0, 0.05, 0.1, 0.15 and 0.3. X-ray diffraction (XRD) study shows all the compounds crystallize in the Fe 2 P-type structure. Magnetic measurements show that the Curie temperature increases from 150 K for Mn 1.1 Fe 0.9 P 0.7 As 0.3 to 380 K for Mn 1.1 Fe 0.9 P 0.7 Ge 0.3 . A field-induced first-order magnetic phase transition is observed above the Curie temperature for the compounds with x up to 0.15. There exists an optimal composition in which the first-order phase transition is the sharpest. The optimal composition for this system is x = 0.1. The maximal magnetic-entropy change derived from the magnetization data is about 40 J/(kg K) for a field change from 0 to 3 T

Nanocrystalline spinel ferrite (MFe2O4, M = Ni, Co, Mn, Mg, Zn) powders prepared by a simple aloe vera plant-extracted solution hydrothermal route

International Nuclear Information System (INIS)

Phumying, Santi; Labuayai, Sarawuth; Swatsitang, Ekaphan; Amornkitbamrung, Vittaya; Maensiri, Santi

2013-01-01

Graphical abstract: This figure shows the specific magnetization curves of the as-prepared MFe 2 O 4 (M = Ni, Co, Mn, Mg, Zn) powders obtained from room temperature VSM measurement. These curves are typical for a soft magnetic material and indicate hysteresis ferromagnetism in the field ranges of ±500 Oe, ±1000 Oe, and ±2000 Oe for the CoFe 2 O 4 , MgFe 2 O 4 and MnFe 2 O 4 respectively, whereas the samples of NiFe 2 O 4 and ZnFe 2 O 4 show a superparamagnetic behavior. Highlights: ► Nanocrystalline MFe 2 O 4 powders were synthesized by a novel hydrothermal method. ► Metal acetylacetonates and aloe vera plant-extracted solution are used. ► This biosynthetic route is very simple and provides high-yield oxide nanomaterials. ► XRD and TEM results indicate that the prepared samples have only spinel structure. ► The maximum M s of 68.9 emu/g at 10 kOe were observed for the samples of MnFe 2 O 4 . - Abstract: Nanocrystalline spinel ferrite MFe 2 O 4 (M = Ni, Co, Mn, Mg, Zn) powders were synthesized by a novel hydrothermal method using Fe(acac) 3 , M(acac) 3 (M = Ni, Co, Mn, Mg, Zn) and aloe vera plant extracted solution. The X-ray diffraction and selected-area electron diffraction results indicate that the synthesized nanocrystalline have only spinel structure without the presence of other phase impurities. The crystal structure and morphology of the spinel ferrite powders, as revealed by TEM, show that the NiFe 2 O 4 and CoFe 2 O 4 samples contain nanoparticles, whereas the MnFe 2 O 4 and MgFe 2 O 4 samples consist of many nanoplatelets and nanoparticles. Interestingly, the ZnFe 2 O 4 sample contains plate-like structure of networked nanocrystalline particles. Room temperature magnetization results show a ferromagnetic behavior of the CoFe 2 O 4 , MnFe 2 O 4 and MgFe 2 O 4 samples, whereas the samples of NiFe 2 O 4 and ZnFe 2 O 4 exhibit a superparamagnetic behavior

Mechanism transition of cell-impedance-controlled lithium transport through Li1-δMn2O4 composite electrode caused by surface-modification and temperature variation

International Nuclear Information System (INIS)

Jung, Kyu-Nam; Pyun, Su-Il

2007-01-01

The mechanism transition of lithium transport through a Li 1-δ Mn 2 O 4 composite electrode caused by the surface-modification and temperature variation was investigated using the galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS) and the potentiostatic current transient technique. From the analyses of the ac-impedance spectra, experimentally measured from unmodified Li 1-δ Mn 2 O 4 and surface-modified Li 1-δ Mn 2 O 4 with MgO composite electrodes, the internal cell resistance of the MgO-modified Li 1-δ Mn 2 O 4 electrode was determined to be much smaller in value than that of the unmodified electrode over the whole potential range. Moreover, from the analysis of the anodic current transients measured on the MgO-modified Li 1-δ Mn 2 O 4 electrode, it was found that the cell-impedance-controlled constraint at the electrode surface is changed to a diffusion-controlled constraint, which is characterised by a large potential step and simultaneously by a small amount of lithium transferred during lithium transport. This strongly suggests that the internal cell resistance plays a significant role in determining the cell-impedance-controlled lithium transport through the MgO-modified Li 1-δ Mn 2 O 4 electrode. Furthermore, from the temperature dependence of the internal cell resistance and diffusion resistance in the unmodified Li 1-δ Mn 2 O 4 composite electrode measured by GITT and EIS, it was concluded that which mechanism of lithium transport will be operative strongly depends on the diffusion resistance as well as on the internal cell resistance

Manganese oxide octahedral molecular sieves as insertion electrodes for rechargeable Mg batteries

KAUST Repository

Rasul, Shahid

2013-11-01

Magnesium has been inserted electrochemically into manganese oxide octahedral molecular sieves (OMS-5 MnO2) at room temperature. Discharge/charge profiles show that a large amount of Mg, i.e., 0.37 Mg/Mn can be inserted electrochemically using 1 M Mg(ClO4)2/AN electrolyte when OMS-5 is prepared in presence of acetylene black. X-ray diffraction analysis and discharge/charge profiles verify that a solid state solution reaction takes place upon Mg insertion into the host lattice with concurrent reduction of Mn4+ to Mn2+. However, upon each reduction of Mn by Mg insertion and resultant dissolution into electrolyte, decrease in the active compound occurs consequently. A low intrinsic electronic conductivity of OMS-5 was suggested to play a vital role in Mg insertion into the host. © 2013 Elsevier Ltd.

Manganese oxide octahedral molecular sieves as insertion electrodes for rechargeable Mg batteries

KAUST Repository

Rasul, Shahid; Suzuki, Shinya; Yamaguchi, Shu; Miyayama, Masaru

2013-01-01

Magnesium has been inserted electrochemically into manganese oxide octahedral molecular sieves (OMS-5 MnO2) at room temperature. Discharge/charge profiles show that a large amount of Mg, i.e., 0.37 Mg/Mn can be inserted electrochemically using 1 M Mg(ClO4)2/AN electrolyte when OMS-5 is prepared in presence of acetylene black. X-ray diffraction analysis and discharge/charge profiles verify that a solid state solution reaction takes place upon Mg insertion into the host lattice with concurrent reduction of Mn4+ to Mn2+. However, upon each reduction of Mn by Mg insertion and resultant dissolution into electrolyte, decrease in the active compound occurs consequently. A low intrinsic electronic conductivity of OMS-5 was suggested to play a vital role in Mg insertion into the host. © 2013 Elsevier Ltd.

Structural, magnetic and magnetocaloric properties of La{sub 0.7}Ca{sub 0.2}Sr{sub 0.1}Mn{sub 1−x}Cr{sub x}O{sub 3} compounds with x = 0, 0.05 and 0.1

Energy Technology Data Exchange (ETDEWEB)

Dhahri, Ah., E-mail: dhahri.ahmad@outlook.fr [Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, BP 1171, Université de Sfax, 3000 (Tunisia); Jemmali, M. [Laboratoire des Sciences des Matériaux et de l’Environnement, Faculté des Sciences de Sfax, BP 1171, Université de Sfax, 3000 (Tunisia); Taibi, K. [Département SDM, FGMGP/USTHB, 16311 (Algeria); Dhahri, E. [Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, BP 1171, Université de Sfax, 3000 (Tunisia); Hlil, E.K. [Institut Néel, CNRS et Université J. Fourier, BP 166, 38042 Grenoble (France)

2015-01-05

Highlights: • The samples crystallize in the rhombohedral structure with the R3{sup ¯}c space group. • Enhancement of T{sub C} for the rhombohedral samples. • The relative cooling power increases with Cr-doping. • All samples exhibit a large magnetocaloric effect. • High values of the magnetoresistance in all samples. - Abstract: Structural, magnetic and magnetocaloric properties of La{sub 0.7}Sr{sub 0.1}Ca{sub 0.2}Mn{sub 1−x}Cr{sub x}O{sub 3} compounds with x = 0, 0.05 and 0.1 have been investigated to shed light on Cr-doping influence. X-ray diffraction studies show that all samples crystallize in the rhombohedral symmetry with R3{sup ¯}c space group. Rietveld refinement structure shows that the insertion of Cr in Mn network modifies the structural parameters such as the volume, Mn–O–Mn angles and the Mn–O bond length. The substitution of Mn by Cr decreases the 2p-3d hybridization between O and Mn ions, reduces the bandwidth and increases the electron–phonon coupling. The investigation of magnetic and magnetocaloric properties reveals that the samples exhibit a paramagnetic(PM)–ferromagnetic (FM) transition with decreasing Curie temperature (T{sub C}) from 294 K to 255 K when Cr doping level increases. The magnetic entropy change (ΔS{sub M}{sup max}) also decreases from 6.20 J kg{sup −1} K{sup −1} for x = 0 to3.80 J kg{sup −1} K{sup −1} for x = 0.1, while the relative cooling power (RCP) increases from 234.5 to 240 J kg{sup −1}, respectively, under a magnetic field of 5 T. These outcomes suggest that Mn-site Cr doping inhibits the enhancement of the magnetocaloric effect in some perovskite manganites. This is explained by the weakening of the ferromagnetic double-exchange interaction between Mn{sup 3+} and Mn{sup 4+} ions.

Fabrication of fully epitaxial magnetic tunnel junctions with a Co2MnSi thin film and a MgO tunnel barrier

International Nuclear Information System (INIS)

Kijima, H.; Ishikawa, T.; Marukame, T.; Matsuda, K.-I.; Uemura, T.; Yamamoto, M.

2007-01-01

Fully epitaxial magnetic tunnel junctions (MTJs) were fabricated with a Co-based full-Heusler alloy Co 2 MnSi (CMS) thin film having the ordered L2 1 structure as a lower electrode, a MgO tunnel barrier, and a Co 50 Fe 50 upper electrode. Reflection high-energy electron diffraction patterns observed in situ for each layer in the MTJ layer structure during fabrication clearly indicated that all layers of the CMS lower electrode, MgO tunnel barrier, and Co 50 Fe 50 upper electrode grew epitaxially. The microfabricated fully epitaxial CMS/MgO/Co 50 Fe 50 MTJs demonstrated relatively high tunnel magnetoresistance ratios of 90% at room temperature and 192% at 4.2 K

Ferromagnetic Peierls insulator state in A Mg4Mn6O15(A =K ,Rb ,Cs )

Science.gov (United States)

Yamaguchi, T.; Sugimoto, K.; Ohta, Y.; Tanaka, Y.; Sato, H.

2018-04-01

Using the density-functional-theory-based electronic structure calculations, we study the electronic state of recently discovered mixed-valent manganese oxides A Mg4Mn6O15(A =K ,Rb ,Cs ) , which are fully spin-polarized ferromagnetic insulators with a cubic crystal structure. We show that the system may be described as a three-dimensional arrangement of the one-dimensional chains of a 2 p orbital of O and a 3 d orbital of Mn running along the three axes of the cubic lattice. We thereby argue that in the ground state the chains are fully spin polarized due to the double-exchange mechanism and are distorted by the Peierls mechanism to make the system insulating.

Hydrothermal synthesis and corrosion behavior of the protective coating on Mg-2Zn-Mn-Ca-Ce alloy

Directory of Open Access Journals (Sweden)

Dan Song

2016-12-01

Full Text Available Protective coatings were synthesized on the Mg-2Zn-Mn-Ca-Ce Mg alloy through the hydrothermal method with de-ionized water as the reagent. The coatings were composed of Mg hydroxide, generally uniform and compact. Hydrogen evolution tests and electrochemical tests in the Hanks’ solution demonstrated that the Mg(OH2 coatings effectively decreased the bio-degradation rate of the Mg alloy substrate. Microstructure observation showed that the coating formation on the secondary phases was more difficult than that on the α-Mg matrix, which led to micro cracks and pores on the secondary phases after drying. Over synthesizing time, the coating layer on secondary phases gradually becomes more compact and uniform. Meanwhile, owing to the thicker and more compact coatings, the corrosion resistance and protective efficiency were significantly improved with longer synthesizing time as well.

Transfer of U, Al and Mn in the water–soil–plant (Solanum tuberosum L.) system near a former uranium mining area (Cunha Baixa, Portugal) and implications to human health

International Nuclear Information System (INIS)

Neves, M.O.; Figueiredo, V.R.; Abreu, M.M.

2012-01-01

Knowledge about metals in crops, grown in contaminated soils around mine sites, is limited and concerns about exposure to hazardous elements through the consumption of contaminated foodstuff, are high. In this study a field experiment was carried out in two agricultural soils located near a former uranium mine area (Cunha Baixa, Portugal). The purpose of the study was to assess the effect of irrigation water quality on soil–potato (Solanum tuberosum L.) crop system and to evaluate if the consumption of the crop represents health risk to the local villagers. The soils were divided in two plots: one irrigated with contaminated water (U: 1.03–1.04 mg/L; Al: 7.5–8.00 mg/L; Mn: 4.52 mg/L) and the other with uncontaminated water (U: 14–10 μg/L; Al: 17–23 μg/L; Mn: 2.4–5.7 μg/L). After irrigation and potato growth, only soil characteristics, as salinity and total U and Mn concentrations were significantly different from those measured at the beginning of the experiment. Within the potato plants, elements were mostly translocated and concentrated in the aerial part: stems and leaves (U: 73–87%; Al: 85–96%; Mn: 85–94%), which minimize the risk of contamination of the edible tissue. In potato tubers, the highest average concentrations (121–590 μg U/kg; 25–64 mg Al/kg; 12–13 mg Mn/kg dry weight) were registered at soil plots irrigated with contaminated water. Uranium and Al were mostly concentrated in the potato peel (88–96 and 76–85%, respectively), and Mn (67–78%) in the pulp, which reinforces the importance of removing peel to minimize human exposure. The risk analysis calculated for non-cancer health effects (hazard quotient), related only to the exposure through the consumption of this basic foodstuff, revealed safety for Cunha Baixa village residents (adults and children) even when potato crop was grown on U enriched soils and irrigated with contaminated water. - Highlights: ► Field experiment with potato in agricultural soils near a

Transfer of U, Al and Mn in the water-soil-plant (Solanum tuberosum L.) system near a former uranium mining area (Cunha Baixa, Portugal) and implications to human health

Energy Technology Data Exchange (ETDEWEB)

Neves, M.O., E-mail: orquidia.neves@ist.utl.pt [Centro de Petrologia e Geoquimica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa (TULisbon), Av. Rovisco Pais 1049-001 Lisboa (Portugal); Figueiredo, V.R., E-mail: vera.figueiredo@ist.utl.pt [Instituto Superior Tecnico, Universidade Tecnica de Lisboa (TULisbon), Av. Rovisco Pais 1049-001 Lisboa (Portugal); Abreu, M.M., E-mail: manuelaabreu@isa.utl.pt [Unidade de Investigacao de Quimica Ambiental, Instituto Superior de Agronomia, Universidade Tecnica de Lisboa (TULisbon), Tapada da Ajuda, 1349-017 Lisboa (Portugal)

2012-02-01

Knowledge about metals in crops, grown in contaminated soils around mine sites, is limited and concerns about exposure to hazardous elements through the consumption of contaminated foodstuff, are high. In this study a field experiment was carried out in two agricultural soils located near a former uranium mine area (Cunha Baixa, Portugal). The purpose of the study was to assess the effect of irrigation water quality on soil-potato (Solanum tuberosum L.) crop system and to evaluate if the consumption of the crop represents health risk to the local villagers. The soils were divided in two plots: one irrigated with contaminated water (U: 1.03-1.04 mg/L; Al: 7.5-8.00 mg/L; Mn: 4.52 mg/L) and the other with uncontaminated water (U: 14-10 {mu}g/L; Al: 17-23 {mu}g/L; Mn: 2.4-5.7 {mu}g/L). After irrigation and potato growth, only soil characteristics, as salinity and total U and Mn concentrations were significantly different from those measured at the beginning of the experiment. Within the potato plants, elements were mostly translocated and concentrated in the aerial part: stems and leaves (U: 73-87%; Al: 85-96%; Mn: 85-94%), which minimize the risk of contamination of the edible tissue. In potato tubers, the highest average concentrations (121-590 {mu}g U/kg; 25-64 mg Al/kg; 12-13 mg Mn/kg dry weight) were registered at soil plots irrigated with contaminated water. Uranium and Al were mostly concentrated in the potato peel (88-96 and 76-85%, respectively), and Mn (67-78%) in the pulp, which reinforces the importance of removing peel to minimize human exposure. The risk analysis calculated for non-cancer health effects (hazard quotient), related only to the exposure through the consumption of this basic foodstuff, revealed safety for Cunha Baixa village residents (adults and children) even when potato crop was grown on U enriched soils and irrigated with contaminated water. - Highlights: Black-Right-Pointing-Pointer Field experiment with potato in agricultural soils near

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1 +xSb solid solutions

Science.gov (United States)

Levin, Emily E.; Bocarsly, Joshua D.; Wyckoff, Kira E.; Pollock, Tresa M.; Seshadri, Ram

2017-12-01

Materials with a large magnetocaloric response are associated with a temperature change upon the application of a magnetic field and are of interest for applications in magnetic refrigeration and thermomagnetic power generation. The usual metric of this response is the gravimetric isothermal entropy change Δ SM . The use of a simple proxy for the Δ SM that is based on density functional theory (DFT) calculations of the magnetic electronic structure suggests that half-Heusler MnNiSb should be a better magnetocaloric than the corresponding Heusler compound MnNi2Sb . Guided by this observation, we present a study of MnNi1 +xSb (x =0 , 0.25, 0.5, 0.75, and 1.0) to evaluate relevant structural and magnetic properties. DFT stability calculations suggest that the addition of Ni takes place at a symmetrically distinct Ni site in the half-Heusler structure and support the observation using synchrotron x-ray diffraction of a homogeneous solid solution between the half-Heusler and Heusler end members. There is a maximum in the saturation magnetization at x =0.5 and the Curie temperature systematically decreases with increasing x . Δ SM for a maximum magnetic field change of Δ H =5 T monotonically decreases in magnitude from -2.93 J kg-1K-1 in the half-Heusler to -1.35 J kg-1K-1 in the Heusler compound. The concurrent broadening of the magnetic transition results in a maximum in the refrigerant capacity at x =0.75 . The Curie temperature of this system is highly tunable between 350 K and 750 K, making it ideal for low grade waste heat recovery via thermomagnetic power generation. The increase in Δ SM with decreasing x may be extendable to other MnNi2Z Heusler systems that are currently under investigation for use in magnetocaloric refrigeration applications.

Effects of magnesium substitution on the magnetic properties of Nd0.7Sr0.3MnO3

International Nuclear Information System (INIS)

Tseggai, M.; Mathieu, R.; Nordblad, P.; Tellgren, R.; Bau, L.V.; Nam, D.N.H.; Phuc, N.X.; Khiem, N.V.; Andre, G.; Bouree, F.

2005-01-01

Effects of magnesium substitution on the magnetic properties of Nd 0.7 Sr 0.3 MnO 3 have been investigated by neutron powder diffraction and magnetization measurements on polycrystalline samples of composition Nd 0.7 Sr 0.3 MnO 3 , Nd 0.6 Mg 0.1 Sr 0.3 MnO 3 , Nd 0.6 Mg 0.1 Sr 0.3 Mn 0.9 Mg 0.1 O 3 , and Nd 0.6 Mg 0.1 Sr 0.3 Mn 0.8 Mg 0.2 O 3 . The pristine compound Nd 0.7 Sr 0.3 MnO 3 is ferromagnetic with a transition temperature occurring at about 210K. Increasing the Mg-substitution causes weakened ferromagnetic interaction and a great reduction in the magnetic moment of Mn. The Rietveld analyses of the neutron powder diffraction (NPD) data at 1.5K for the samples with Mg concentration, y=0.0 and 0.1, show ferromagnetic Mn moments of 3.44(4) and 3.14(4)μ B , respectively, which order along the [001] direction. Below 20K the Mn moments of these samples become canted giving an antiferromagnetic component along the [010] direction of about 0.4μ B at 1.5K. The analyses also show ferromagnetic polarization along [001] of the Nd moments below 50K, with a magnitude of almost 1μ B at 1.5K for both samples. In the samples with Mg substitution of 0.2 and 0.3 only short range magnetic order occurs and the magnitude of the ferromagnetic Mn moments is about 1.6μ B at 1.5K for both samples. Furthermore, the low-temperature NPD patterns show an additional very broad and diffuse feature resulting from short range antiferromagnetic ordering of the Nd moments

Discharge capacity and microstructures of La Mg Pr Al Mn Co Ni alloys for nickel-metal hydride batteries

Energy Technology Data Exchange (ETDEWEB)

Casini, J.C.S.; Galdino, G.S.; Ferreira, E.A.; Takiishi, H.; Faria, R.N., E-mail: jcasini@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (DM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Dept. de Metalurgia

2010-07-01

La{sub 0.7-x}Mg{sub x}Pr{sub 0.3}Al{sub 0.3}Mn{sub 0.4}Co{sub 0.5}Ni{sub 3.8} (x = 0.0, 0.3 and 0.7) alloys have been investigated aiming the production of negative electrodes for nickel-metal hydride batteries. The alloys employed in this work were used in the as cast state. The results showed that the substitution of magnesium by lanthanum increased the discharge capacity of the Ni-MH batteries. A battery produced with the La{sub 0.4}Mg{sub 0.3}Pr{sub 0.3}Al{sub 0.3}Mn{sub 0.4}Co{sub 0.5}Ni{sub 3.8} alloy shown a high discharge capacity (380mAh/g) also good stability compared to other alloys. The electrode materials were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). (author)

Piezoelectric properties and temperature stability of Mn-doped Pb(Mg1/3Nb2/3)-PbZrO3-PbTiO3 textured ceramics

Science.gov (United States)

Yan, Yongke; Cho, Kyung-Hoon; Priya, Shashank

2012-03-01

In this letter, we report the electromechanical properties of textured 0.4Pb(Mg1/3Nb2/3)O3-0.25PbZrO3-0.35PbTiO3 (PMN-PZT) composition which has relatively high rhombohedral to tetragonal (R-T) transition temperature (TR-T of 160 °C) and Curie temperature (TC of 234 °C) and explore the effect of Mn-doping on this composition. It was found that MnO2-doped textured PMN-PZT ceramics with 5 vol. % BaTiO3 template (T-5BT) exhibited inferior temperature stability. The coupling factor (k31) of T-5BT ceramic started to degrade from 75 °C while the random counterpart showed a very stable tendency up to 180 °C. This degradation was associated with the "interface region" formed in the vicinity of BT template. MnO2 doped PMN-PZT ceramics textured with 3 vol. % BT and subsequently poled at 140 °C (T-3BT140) exhibited very stable and high k31 (>0.53) in a wide temperature range from room temperature to 130 °C through reduction in the interface region volume. Further, the T-3BT140 ceramic exhibited excellent hard and soft combinatory piezoelectric properties of d33 = 720 pC/N, k31 = 0.53, Qm = 403, tan δ = 0.3% which are very promising for high power and magnetoelectric applications.

Low Temperature Mechanical Properties of Scandium-Modified Al-Zn-Mg-Cu Alloys

National Research Council Canada - National Science Library

Senkov, O

2002-01-01

Tensile properties of three wrought alloys, (1) Al-10Zn-3Mg-1.2Cu-0.15Zr, (2) Al-10Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc, and (3) Al-12Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc were studied in T6 and T7 conditions at 298K and 77K...

Investigation on the Effect of Sub-Zero Treatment on Micro-Hardness and Microstructure of GTAW Welded Al-Si-Mg-Mn Alloy

Science.gov (United States)

Devanathan, R.; Yuvarajan, D.; Christopher Selvam, D.; Venkatamuni, T.

2018-02-01

In this work, the effect of sub-zero treatment on the mechanical properties of an Al-Si-Mg-Mn alloy welded by GTAW (gas tungsten arc welding) leads to significant softening in the welded region. The latter is due to melting and resolidification in the welded region, which have resulted in decomposition of the strengthening precipitates. The experiments were performed on GTAW welded plates of 6 mm thickness by varying the heat inputs, namely, of 370, 317.1, 277.5, 246.4, and 222 J/mm, and sub-zero treatment time periods. The Sub-Zero treatment was performed at-45°C using dry ice; hardness and microstructure investigations were performed in the welded region of the Al‒Si-Mg-Mn alloy that was studied in two different conditions, namely, as-welded and in that formed after post weld sub-zero treatment with artificial aging. It was found that the post weld Sub-Zero treatment followed by artificial aging had led to realization of significantly higher hardness values in the welded region due to the recurrence of the precipitation sequence.

Analysis of (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8}:Eu{sup 2+}, Mn{sup 2+} phosphors for application in solid state lighting

Energy Technology Data Exchange (ETDEWEB)

Han, J.K. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); Piqutte, A.; Hannah, M.E. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Drive Beverly, MA 01915 (United States); Hirata, G.A. [Centro de Nanociencias y Nanotecnolgía, Universidad Nacional Autónoma de México, Km. 107 Carretera Tijuana-Ensenada Apdo, Ensenada MX CP 22860 (Mexico); Talbot, J.B. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); University of California, San Diego, Department of Nanoengineering, La Jolla, CA 92093 (United States); Mishra, K.C. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Drive Beverly, MA 01915 (United States); McKittrick, J., E-mail: jmckittrick@ucsd.edu [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); University of California, San Diego, Department of Mechanical and Aerospace Engineering, La Jolla, CA 92093 (United States)

2014-04-15

The luminescence properties of Eu{sup 2+} and Mn{sup 2+} co-activated (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8} phosphors prepared by combustion synthesis were studied. Eu{sup 2+}-activated (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8} has a broad blue emission band centered at 450–485 nm and Eu{sup 2+}–Mn{sup 2+}-activated (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8} exhibits a red emission around 620–703 nm, depending on the relative concentrations of Ba, Ca and Sr. The particle size of Eu{sup 2+} and Mn{sup 2+} co-activated (Ba,Ca){sub 3}MgSi{sub 2}O{sub 8} ranges from 300 nm to 1 μm depending on the metal ion and are agglomerated due to post-synthesis, high temperature annealing. The green emission of Ba{sub 3}MgSi{sub 2}O{sub 8} originates from secondary phases (Ba{sub 2}SiO{sub 4} and BaMgSiO{sub 4}) confirmed by emission spectra and X-ray diffraction patterns. The secondary phases of Ba{sub 3}MgSi{sub 2}O{sub 8} are removed by the addition of Sr. The quantum efficiencies range from 45% to 70% under 400 nm excitation and the lifetime of red emission of Ba{sub 3}MgSi{sub 2}O{sub 8} decreases significantly with increasing temperature, which is 54% at 400 K of that at 80 K compared to that of blue emission (90% at 400 K of that at 80 K). -- highlights: • (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8}:Eu{sup 2+}, Mn{sup 2+} phosphors were prepared by a combustion synthesis method. • The emission spectra consist of broad blue-emission band and red-emission band. • The quantum efficiencies range between 45% and 70%, depending on the relative concentrations of Ba, Ca and Sr. • The secondary phases were eliminated by additions of Sr. • Lifetime of the red-emission decreases with increasing temperature, suggesting that these phosphors are not useful for solid state lighting applications.

Synthesis and characterization of nanosized Mg{sub x}Mn{sub 1−x}Fe{sub 2}O{sub 4} ferrites by both sol-gel and thermal decomposition methods

Energy Technology Data Exchange (ETDEWEB)

De-León-Prado, Laura Elena, E-mail: laura.elena.prado@gmail.com [Cinvestav-Unidad Saltillo, Av. Industria Metalúrgica #1062, Parque Industrial Saltillo-Ramos Arizpe, CP 25900, Ramos Arizpe, Coahuila, México (Mexico); Cortés-Hernández, Dora Alicia; Almanza-Robles, José Manuel; Escobedo-Bocardo, José Concepción; Sánchez, Javier; Reyes-Rdz, Pamela Yajaira; Jasso-Terán, Rosario Argentina [Cinvestav-Unidad Saltillo, Av. Industria Metalúrgica #1062, Parque Industrial Saltillo-Ramos Arizpe, CP 25900, Ramos Arizpe, Coahuila, México (Mexico); Hurtado-López, Gilberto Francisco [Centro de Investigación en Química Aplicada, Blvd. Enrique Reyna Hermosillo #140, CP 25294, Saltillo, Coahuila, México (Mexico)

2017-04-01

This work reports the synthesis of Mg{sub x}Mn{sub 1−x}Fe{sub 2}O{sub 4} (x=0–1) nanoparticles by both sol-gel and thermal decomposition methods. In order to determine the effect of synthesis conditions on the crystal structure and magnetic properties of the ferrites, the synthesis was carried out varying some parameters, including composition. By both methods it was possible to obtain ferrites having a single crystalline phase with cubic inverse spinel structure and a behavior near to that of superparamagnetic materials. Saturation magnetization values were higher for materials synthesized by sol-gel. Furthermore, in both cases particles have a spherical-like morphology and nanometric sizes (11–15 nm). Therefore, these materials can be used as thermoseeds for the treatment of cancer by magnetic hyperthermia. - Highlights: • Mg–Mn ferrites were synthesized by sol-gel and thermal decomposition methods. • Materials showed a single cubic inverse spinel crystalline structure. • Ferrites have a soft ferrimagnetic behavior close to superparamagnetic materials.

Microstructure and mechanical properties of Mg-Al-Mn-Ca alloy sheet produced by twin roll casting and sequential warm rolling

International Nuclear Information System (INIS)

Wang Yinong; Kang, Suk Bong; Cho, Jaehyung

2011-01-01

Research highlights: → This work, taking AM30 + 0.2Ca alloy as experimental material, will provide some new information as follows: one is microstructural difference between twin roll cast and ingot cast AM31-0.2Ca alloy. The other is the comparison of tensile properties after warm rolling and annealing. Suggesting the possibility of the development of wrought magnesium alloy sheets by strip casting. - Abstract: Microstructural evolution and mechanical properties of twin roll cast (TRC) Mg-3.3 wt.%Al-0.8 wt.%Mn-0.2 wt.%Ca (AM31 + 0.2Ca) alloy strip during warm rolling and subsequent annealing were investigated in this paper. The as-TRC alloy strip shows columnar dendrites in surface and equiaxed dendrites in center regions, as well as finely dispersed primary Al 8 Mn 5 particles on interdendritic boundaries which result in the beneficial effect on microstructural refinement of strip casting. The warm rolled sheets show intensively deformed band or shear band structures, as well as finely and homogeneously dispersed Al-Mn particles. No evident dynamic recrystallization (DRX) takes place during warm rolling process, which is more likely attributed to the finely dispersed particle and high solid solution of Al and Mn atoms in α-Mg matrix. After annealing at 350 deg. C for 1 h, the warm rolled TRC sheets show fine equiaxed grains around 7.8 μm in average size. It has been shown that the present TRC alloy sheet has superior tensile strength and comparative elongation compared to commercial ingot cast (IC) one, suggesting the possibility of the development of wrought magnesium alloy sheets by twin roll strip casting processing. The microstructural evolution during warm rolling and subsequent annealing as well as the resulting tensile properties were analyzed and discussed.

Industrial contamination of soil related to some active and closed mine facilities in the Republic of Macedonia

Directory of Open Access Journals (Sweden)

Tasev Goran K.

2015-01-01

Full Text Available Several industrial pollution sources at the territory of the Republic of Macedonia, were studied, one Pb-Zn mine with mill, one copper mine with mill and copper leaching facility, as well as one former Pb-Zn smelting facility near the city of Veles and one Fe-Ni smelting facility near the city of Kavadarci. The concentrations of heavy metals at Veles hot-spot were in the range: 20÷1823 mg kg- 1Pb, 29÷2395 mg kg-1Zn, 28÷65 mgkg-1Cd, 27÷82 mg kg-1 Cu, 39÷164 mg kg-1Ni, 508÷938 mgkg-1Mn and 1.6÷3.8% Fe, all of them being above Dutch standard optimal values. The vicinity of the Feni plant displayed concentrations of heavy metals as follows: 16÷31 mg kg-1 Pb, 117÷286 mgkg-1 Zn, 13÷24 mg kg-1Co, 42÷119 mg kg-1 Cu, 158÷292 mg kg-1Ni, 119÷236 mg kg-1 Cr and 2.24÷3.79% Fe. Airborne dust measurements around the Zletovo mine displayed multiplexed above standard values, with an exception of nickel, there enrichment factors ranged from mediate ones such were those for copper of 20.8, cadmium of 28.7, arsenic of 32.5 up to high ones for zinc with 341.7 and lead 925. Soil samples around the Zletovo mine displayed: 19.3-76.9 g kg-1 Fe, 643-28000 mg kg-1 Mn, 42.3-529.66 mg kg-1 Pb and 138-3240 mg kg-1 Zn. Finally around the Bucim copper mine the results displayed the following findings: 13.1÷225 mg kg-1 As, 0.67÷17.9 mg kg-1 Cd, 30.1÷171 mg kg-1 Cr, 17.8÷1734 mg kg-1 Cu, 9.8÷69.4 mg kg-1 Ni, 46÷3456 mg kg-1 Pb, 88÷3438 mg kg-1 Zn, 169÷998 mg kg-1 Mn, 0.73÷5.02% Fe.

Structural, magnetic and transport properties of Mn3.1Sn0.9 and Mn3.1Sn0.9N compounds

International Nuclear Information System (INIS)

Feng, W.J.; Li, D.; Ren, W.J.; Li, Y.B.; Li, W.F.; Li, J.; Zhang, Y.Q.; Zhang, Z.D.

2007-01-01

The cubic anti-perovskite Mn 3.1 Sn 0.9 N compound is prepared via nitrogenation of the hexagonal Mn 3.1 Sn 0.9 compound. A magnetic phase diagram of Mn 3.1 Sn 0.9 compound is constructed by analysis of data of its magnetic properties. For Mn 3.1 Sn 0.9 N compound, parasitic ferromagnetism exists in the temperature range of 5-370 K, besides a spin-reorientation at about 280 K. Mn 3.1 Sn 0.9 compound exhibits a metallic conducting behavior, while Mn 3.1 Sn 0.9 N displays a metal-nonmetal transition due to the electron localization caused by the static disorder. The differences of the physical properties between the both compounds, are discussed, in terms of the correlation of the hexagonal DO 19 and the cubic anti-perovskite structures, the reduction of the distances between Mn atoms, and the spin-pairing or charge transfer effect due to the electron donation by N 2p to Mn 3d states after introduction of N atoms into the interstitial sites of Mn 3.1 Sn 0.9 compound

Anthrax and the Geochemistry of Soils in the Contiguous United States

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Dale W. Griffin

2014-08-01

Full Text Available Soil geochemical data from sample sites in counties that reported occurrences of anthrax in wildlife and livestock since 2000 were evaluated against counties within the same states (MN, MT, ND, NV, OR, SD and TX that did not report occurrences. These data identified the elements, calcium (Ca, manganese (Mn, phosphorus (P and strontium (Sr, as having statistically significant differences in concentrations between county type (anthrax occurrence versus no occurrence. Tentative threshold values of the lowest concentrations of each of these elements (Ca = 0.43 wt %, Mn = 142 mg/kg, P = 180 mg/kg and Sr = 51 mg/kg and average concentrations (Ca = 1.3 wt %, Mn = 463 mg/kg, P = 580 mg/kg and Sr = 170 mg/kg were identified from anthrax-positive counties as prospective investigative tools in determining whether an outbreak had “potential” or was “likely” at any given geographic location in the contiguous United States.

Nanoporous LiMn2O4 spinel prepared at low temperature as cathode material for aqueous supercapacitors

Science.gov (United States)

Wang, F. X.; Xiao, S. Y.; Gao, X. W.; Zhu, Y. S.; Zhang, H. P.; Wu, Y. P.; Holze, R.

2013-11-01

LiMn2O4 spinel was prepared by a hydrothermal method using α-MnO2 nanotubes as precursor at 180 °C, a temperature much lower than that in previously reported methods. It is nanoporous with a pore size of about 40-50 nm and a BET surface area of 9.76 m2 g-1. It exhibits a high specific capacitance of 189 F g-1 at 0.3 A g-1 as a cathode for an aqueous supercapacitor. Even at 12 A g-1, it still has a capacitance of 166 F g-1. After 1500 cycles, there is no evident capacity fading. The LiMn2O4 cathode can deliver an energy density of 31.9 Wh kg-1 at 3480 W kg-1 and even maintain 19.4 Wh kg-1 at about 5100 W kg-1 based on the mass of LiMn2O4.

Influence of Mn incorporation for Ni on the magnetocaloric properties of rapidly solidified off-stoichiometric NiMnGa ribbons

Energy Technology Data Exchange (ETDEWEB)

Dey, Sushmita; Singh, Satnam; Roy, R.K.; Ghosh, M.; Mitra, A.; Panda, A.K., E-mail: akpanda@nmlindia.org

2016-01-01

The present investigation addresses the magnetocaloric behaviour in a series of Ni{sub 77−x}Mn{sub x}Ga{sub 23} (x=23, 24, 25, 27 and 29) rapidly solidified alloys prepared in the form of ribbons by melt spinning technique. The approach of the study is to identify the off-stoichiometric composition wherein room temperature magneto-structural transformation is achieved. The alloy chemistry was tailored through Mn incorporation for Ni such that the magnetic and structural transitions were at close proximity to achieve highest entropy value of ΔS equal to 8.51 J Kg{sup −1} K{sup −1} for #Mn{sub 24} ribbon measured at an applied field of 3 T. When such transitions are more staggered as in #Mn{sub 29} the entropy value of ribbon reduced to as low as 1.61 J Kg{sup −1} K{sup −1}. Near room temperature transformations in #Mn{sub 24} ribbon have been observed through calorimetric and thermomagnetic evaluation. Reverse martensitic transformation (martensite→autstenite) temperature indicates not only distinct change in the saturation flux density but also an inter-martensitic phase. Microstructural analysis of #Mn{sub 24} alloy ribbon revealed structural ordering with the existence of plate morphology evidenced for martensitic phase. - Highlights: • Magnetocaloric effect in a series of melt spun NiMnGa ribbon is addressed. • The alloy series revealed austenitic state as well as its presence with martensite. • The morphology of the ribbons has been shown and discussed through phase analysis. • Influence of magnetising field on entropy and relative cooling power is discussed. • Influence of intermartensitic state on magnetization plots have also been shown.

The effect of disorder on electronic and magnetic properties of quaternary Heusler alloy CoFeMnSi with LiMgPbSb-type structure

International Nuclear Information System (INIS)

Feng, Yu; Chen, Hong; Yuan, Hongkuan; Zhou, Ying; Chen, Xiaorui

2015-01-01

Thin films based on Heusler alloy often lost their theoretical predicted ultra-high spin polarization owing to the appearance of disorder. Using the first-principles calculations within density functional theory (DFT), we investigate the effect of disorder including antisite and swap on electronic and magnetic properties of quaternary Heusler alloy CoFeMnSi with LiMgPbSb-type structure. Twelve kinds of antisites and six kinds of swap disorders are proposed and studied comprehensively. In our calculations, Co(Fe)-, Mn(Fe)-, Si(Mn)-antisite and Co–Fe swap disorders are most favorable due to their lowest formation energies. Moreover, the positive binding energies of Co–Fe, Co–Si, Fe–Si and Mn–Si swap disorders with respect to their corresponding antisite disorders indicate that these complex swap disorders are more stable compared with their corresponding isolated antisite disorders. The investigations on density of states (DOS) show that the spin down energy gap of disordered structures suffers contraction and their DOS entirely move towards lower zone. Besides, the 100% spin polarization is maintained in all structures with antisite and swap disorders except for those with Co(Mn)-, Co(Si)-antisite and Co–Mn, Co–Si swap disorders. Therefore, the half-metallicity of quaternary Heusler alloy CoFeMnSi is quite robust against interfering effects such as Si(Mn), Co(Fe) and Co–Fe disorders most possibly formed in the growth. - Highlights: • CoFeMnSi with LiMgPbSb-type structure is found to be a half-metallic ferromagnet. • Si(Mn), Co(Fe), Mn(Fe) antisites and Co–Fe swap disorders are most likely to form. • The half-metallicity of CoFeMnSi is robust against the most possible disorders. • The magnetic moments of the most possible disorders follow the Pauli-Slater rule

Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins

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Majid Abdouss

2018-01-01

How to Cite: Abdouss, M., Arsalanfar, M., Mirzaei, N., Zamani, Y. (2018. Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 97-112 (doi:10.9767/bcrec.13.1.1222.97-112

The effect of high charging rates activation on the specific discharge capacity and efficiency of a negative electrode based on a LaMgAlMnCoNi alloy

International Nuclear Information System (INIS)

Ferreira, E.A.; Zarpelon, L.M.C.; Casini, J.C.S.; Takiishi, H.; Faria, R.N.

2009-01-01

A nickel-metal hydride (Ni-MH) rechargeable battery has been prepared using a La 0.7 Mg 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy as the negative electrode. The maximum discharge capacity of the La 0.7 Mg 0.3 Al 0.3 Mn 0.4 Co 0.5 Ni 3.8 alloy has been determined (350 mAh/g). Using a high starting charging rate (2857 mAg -1 ) an efficiency of 49% has been achieved in the 4 th cycle. The alloy and powders have been characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). (author)

New insights into microstructural evolution of epitaxial Ni-Mn-Ga films on MgO (1 0 0) substrate by high-resolution X-ray diffraction and orientation imaging investigations

Science.gov (United States)

Sharma, Amit; Mohan, Sangeneni; Suwas, Satyam

2018-04-01

In this work, a detailed investigation has been performed on hetero-epitaxial growth and microstructural evolution in highly oriented Ni-Mn-Ga (1 0 0) films grown on MgO (1 0 0) substrate using high-resolution X-ray diffraction and orientation imaging microscopy. Mosaicity of the films has been analysed in terms of tilt angle, twist angle, lateral and vertical coherence length and threading dislocation densities by performing rocking curve measurements and reciprocal space mapping. Density of edge dislocations is found to be an order of magnitude higher than the density of screw dislocations, irrespective of film thickness. X-ray pole figure measurements have revealed an orientation relationship of ? || (1 0 0)MgO; ? || [0 0 1]MgO between the film and substrate. Microstructure predicted by X-ray diffraction is in agreement with that obtained from electron microscopy and atomic force microscopy. The evolution of microstructure in the film with increasing thickness has been explained vis-à-vis dislocation generation and growth mechanisms. Orientation imaging microscopy observations indicate evolutionary growth of film by overgrowth mechanism. Decrease in coercivity with film thickness has been explained as an interplay between stress field developed due to crystal defects and magnetic domain pinning due to surface roughness.

Nutritive quality of romanian hemp varieties (Cannabis sativa L. with special focus on oil and metal contents of seeds

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Mihoc Marcela

2012-10-01

Full Text Available Abstract Background The study aims to determine the nutritional value of hemp seed expressed by the oil content and by the concentration of metals (Ca, Mg, K, Fe, Mn, Zn and Cd, for five varieties of monoecious and dioecious hemp seeds approved in Romania, comparative with the concentration of these metals in the soil. Results The content of oil in hempseed registers a slight decrease in the production records of 2011, losses due to drought and low levels of precipitation during the growth period. The greatest loss is found in Diana monoecious variety (26.54-20.82% followed by Zenit varieties (27.37-22.97%, Armanca (29.27-25.32%, Silvana (28.89-25.04% and Denise (26.96-25.30%. Siccative hemp oil has a yellowish green color and an iodine index of 140–156 g I2/100 g oil. Hemp seed are rich in mineral based Ca (144–955 mg/100 g seed, Mg (237–694 mg/100 g seed, K (463–2821 mg/100 g seed, Fe (1133-2400 mg.kg-1, Mn (63–110 mg.kg-1 and Zn (42-94 mg.kg-1. For the soil the following macroelements concentrations were determined: Ca (2100–2520 mg.kg-1, Mg (320–376 mg.kg-1 and K (232–257 mg.kg-1. Mn (156–197 mg.kg-1 and Zn (54–67 mg.kg-1 remain within normal limits for Romania. The soils in the experience area contain large amounts of Fe (19000–20430 mg.kg-1. The presence of K in large quantities determines the accumulation of large quantities of Fe in the soil. Conclusion Hempseed belonging to the five Romanian varieties are rich source of nutrients (Ca, Mg, K and unsaturated oil easily digestible by the body, but the presence of Cd concentrations above the upper limit puts a question mark over the use of seeds in various food products. Hemp extracts easily certain metals from the soil. Significant amounts of Fe (1133–2400 mg.kg-1, Mn (63–110 mg.kg-1, Zn (42–94 mg.kg-1 and Cd (1.3-4.0 mg.kg-1 are found in hemp seeds. Hemp (Cannabis sativa L. is included among plants suitable for phytoremediation of soil contaminated with cadmium

Attestation in self-propagating combustion approach of spinel AFe_2O_4 (A = Co, Mg and Mn) complexes bearing mixed oxidation states: Magnetostructural properties

International Nuclear Information System (INIS)

Bennet, J.; Tholkappiyan, R.; Vishista, K.; Jaya, N. Victor; Hamed, Fathalla

2016-01-01

Highlights: • Spinel type ferrite compounds AFe_2O_4 (A = Co, Mg and Mn) have been successfully prepared by self-propagating combustion method using glycine as fuel. • To investigate and confirms the presence of phases in the synthesized ferrite nanoparticles by XRD and FTIR analysis. • The formation of mixed oxidation state of cobalt (Co"2"+ and Co"3"+), iron (Fe"2"+ and Fe"3"+) and manganese (Mn"2"+ and Mn"3"+) ions were studied and confirmed from XPS analysis. • The magnetic properties of the synthesized ferrites were studied by VSM measurement. - Abstract: Spinel type nano-sized ferrite compounds AFe_2O_4 (A = Co, Mg and Mn) have been successfully prepared by self-propagating combustion method using glycine as fuel at 400 °C under air atmosphere for 4 h. The crystal structure, chemical composition, morphology and magnetic properties of the synthesized samples were characterized by X−ray diffraction, Fourier transform infrared spectroscopy, X−ray photoelectron spectroscopy, Energy dispersive X−ray, Scanning and Transmission electron microscopy and vibrating sample magnetometer. The chemical reaction and role of fuel on the nanoparticles formation were discussed. The XRD pattern of the synthesized samples shows the formation of pure phase with average crystallite size of 97, 57 and 98 nm from Scherrer formula and 86, 54 and 87 nm from Williamson and Hall (W–H) formula respectively. FTIR absorption spectra revealed that the presence of strong absorption peaks near 400–600 cm"−"1 corresponds to tetrahedral and octahedral complex of spinel ferrites. The relative concentrations of electronic states of elements such as cobalt (Co"2"+ and Co"3"+), iron (Fe"2"+ and Fe"3"+) and manganese (Mn"2"+ and Mn"3"+) oxidation states were studied from XPS and it is found that 55% of Fe ions are in Fe"2"+ state and the remaining is in Fe"3"+ state and thus the cationic distribution of Fe ions occurred in both tetrahedral and octahedral sites. SEM analysis

CNS bioavailability and radiation protection of normal hippocampal neurogenesis by a lipophilic Mn porphyrin-based superoxide dismutase mimic, MnTnBuOE-2-PyP5+

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David Leu

2017-08-01

Full Text Available Although radiation therapy can be effective against cancer, potential damage to normal tissues limits the amount that can be safely administered. In central nervous system (CNS, radiation damage to normal tissues is presented, in part, as suppressed hippocampal neurogenesis and impaired cognitive functions. Mn porphyrin (MnP-based redox active drugs have demonstrated differential effects on cancer and normal tissues in experimental animals that lead to protection of normal tissues and radio- and chemo-sensitization of cancers. To test the efficacy of MnPs in CNS radioprotection, we first examined the tissue levels of three different MnPs – MnTE-2-PyP5+(MnE, MnTnHex-2-PyP5+(MnHex, and MnTnBuOE-2-PyP5+(MnBuOE. Nanomolar concentrations of MnHex and MnBuOE were detected in various brain regions after daily subcutaneous administration, and MnBuOE was well tolerated at a daily dose of 3 mg/kg. Administration of MnBuOE for one week before cranial irradiation and continued for one week afterwards supported production and long-term survival of newborn neurons in the hippocampal dentate gyrus. MnP-driven S-glutathionylation in cortex and hippocampus showed differential responses to MnP administration and radiation in these two brain regions. A better understanding of how preserved hippocampal neurogenesis correlates with cognitive functions following cranial irradiation will be helpful in designing better MnP-based radioprotection strategies. Keywords: Mn porphyrin, Bioavailability, BMX-001, Hippocampus, Neurogenesis, Radioprotection

Oxidation-etching preparation of MnO2 tubular nanostructures for high-performance supercapacitors.

Science.gov (United States)

Zhu, Jixin; Shi, Wenhui; Xiao, Ni; Rui, Xianhong; Tan, Huiteng; Lu, Xuehong; Hng, Huey Hoon; Ma, Jan; Yan, Qingyu

2012-05-01

1D hierarchical tubular MnO(2) nanostructures have been prepared through a facile hydrothermal method using carbon nanofibres (CNFs) as sacrificial template. The morphology of MnO(2) nanostructures can be adjusted by changing the reaction time or annealing process. Polycrystalline MnO(2) nanotubes are formed with a short reaction time (e.g., 10 min) while hierarchical tubular MnO(2) nanostructures composed of assembled nanosheets are obtained at longer reaction times (>45 min). The polycrystalline MnO(2) nanotubes can be further converted to porous nanobelts and sponge-like nanowires by annealing in air. Among all the types of MnO(2) nanostructures prepared, tubular MnO(2) nanostructures composed of assembled nanosheets show optimized charge storage performance when tested as supercapacitor electrodes, for example, delivering an power density of 13.33 kW·kg(-1) and a energy density of 21.1 Wh·kg(-1) with a long cycling life over 3000 cycles, which is mainly related to their features of large specific surface area and optimized charge transfer pathway.

Magnetic soft mode behaviour investigated via multi-spin flip Raman spectroscopy on near surface Cd{sub 1-x}Mn{sub x}Te/Cd{sub 1-y}Mg{sub y}Te quantum wells

Energy Technology Data Exchange (ETDEWEB)

Kehl, Christian

2011-03-28

The main motivation for this thesis was the experimental confirmation of the theoretically predicted magnetic soft mode and the analysis of its dependence on the hole-concentration and external B-field, as well as its disappearance with increasing sample temperature. For that purpose, CdMnTe/CdMgTe QWs (Mn: 0.6%, 1.0%) positioned close to the sample surface (13-19 nm) were investigated in an in-plane applied external magnetic field (up to 4.5 T in Voigt-geometry) via a two-colour experiment i.e. using two light sources. This allows the spin excitation of Mn-ions by simultaneously tuning the hole-concentration towards the ferromagnetic phase transition by photo-generated carriers. Thus, one tuneable laser is responsible for resonant below-barrier excitation as a probe for Multi-SF Raman scattering. The other laser excites photo-generated carriers from above barrier (2.41 eV) for tuning the hole concentration in the QW. Positioning the QW close to the sample surface causes a surface-induced p-doping of the QW (intrinsic hole concentration in the QW) and enables the active tuning of the hole concentration by photo-generated carriers due to different tunnelling behaviour of electrons and holes from the QW to the surface. The Mn-g-factor was decreased by quasi-continuously increasing the above-barrier illumination, while the below-barrier excitation was kept at a constant low power. This results in a Mn-g-factor reduction starting from its atomic value g=2.01 to lowest evaluated Mn-g-factor in this thesis g=1.77. This is a magnetic softening of 12%. Apart from the general magnetic soft mode behaviour at low temperatures, one of the main experimental results in this thesis is the confirmation of the theoretical prediction that the magnetic soft mode behaviour in the external B-field does not only depend on the carrier concentration but also on the B-field strength itself. An additional aspect is the temperature dependence of the magnetic soft mode. The Mn

Part II. Large scale applications of Ni{sub x}Mn{sub 0.8-x}Mg{sub 0.2}Fe{sub 2}O{sub 4}; 0.1 {<=} x {<=} 0.35 using laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Ahmed, M.A., E-mail: moala1947@yahoo.com [Materials Science. Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Bishay, Samiha T. [Department of Physics, Faculty of Girls for Art, Science and Education, Ain Shams University, Cairo (Egypt); El-dek, S.I.; Omar, G. [Materials Science. Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

2011-07-28

Highlights: >X-ray diffractograms of Ni{sub x}Mn{sub 0.8-x}Mg{sub 0.2}Fe{sub 2}O{sub 4} samples before and after laser irradiation are characteristic of cubic spinel structure with better crystallinity after irradiation. > The crystal size of the ferrite increases after laser irradiation. > The main conduction mechanism in the investigated system is the correlated barrier hopping and it is the same before and laser irradiation. > The conductivity decreases after laser irradiation. - Abstract: Ni{sub x}Mn{sub 0.8-x}Mg{sub 0.2}Fe{sub 2}O{sub 4}; 0.1 {<=} x {<=} 0.35 was prepared by standard ceramic technique at sintering temperature 1200 deg. C using heating / cooling rate 4 deg. C/min. The samples were irradiated by Nd YAG pulsed laser with energy of the pulse 250 mJ. X-ray diffractograms reveal cubic spinel structure for all the samples before and after laser irradiation. After laser irradiation, better crystallinity was obtained in a form of an increase in the calculated crystal size. This increase was discussed as due to the change in the valence of some ions like Fe{sup 3+}, Ni{sup 2+} and Mn{sup 2+}. The conductivity of all the investigated samples decreases after laser irradiation and becomes temperature independent for a wider range than that before irradiation. This was ascribed to electron rearrangement after laser irradiation. Accordingly, these ferrites are recommended to be useful in electronic devices.

Raman spectroscopy of DNA-metal complexes. I. Interactions and conformational effects of the divalent cations: Mg, Ca, Sr, Ba, Mn, Co, Ni, Cu, Pd, and Cd

OpenAIRE

Duguid, J.; Bloomfield, V.A.; Benevides, J.; Thomas Jr, G.J.

1993-01-01

Interactions of divalent metal cations (Mg2+, Ca2+, Ba2+, Sr2+, Mn2+, Co2+, Ni2+, Cu2+, Pd2+, and Cd2+) with DNA have been investigated by laser Raman spectroscopy. Both genomic calf-thymus DNA (> 23 kilobase pairs) and mononucleosomal fragments (160 base pairs) were employed as targets of metal interaction in solutions containing 5 weight-% DNA and metal:phosphate molar ratios of 0.6:1. Raman difference spectra reveal that transition metal cations (Mn2+, Co2+, Ni2+, Cu2+, Pd2+, and Cd2+) ind...

Variations of Ni, Cr and Mn Concentration in Soils Formed Along a Toposequence of Ultrabasic Rocks in Western Mashhad

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S. Akbari

2016-02-01

Full Text Available Introduction: Parent materials as one of the main soil formation factors have a great impact on the concentration of heavy metals in the soil. Heavy metals are released to the soil during weathering and pedogenic processes. Ultrabasic rocks are known as the potential natural source of heavy metals, especially Ni, Cr and Mn in the soil. Average concentrations of Ni and Cr in the soils are 84 and 34 mg kg-1, respectively; while, in soil derived from ultrabasic parent material, the concentration of these elements may reach up to 100000 mg kg-1. Binaloud zone in northeastern composed of different geological materials. There is a narrow band of ophiolitic rocks in this zone that located along Mashhad city. The geochemical behavior of ultrabsic rocks and the associated soil have been frequently studied mostly in humid regions. But, there are a few research works done in arid environments. The objective of this study was to investigate the physical and chemical properties and concentrations of Ni, Cr and Mn in soils formed along a toposequence of ultrabasic rocks in western Mashhad. Materials and Methods: The study area is located in the hilly land landscape of Binaloud zone in the Western part of Mashhad. Mean annual precipitation and temperature is 260 mm and 13.7 oC, respectively. Soil temperature and moisture regimes are thermic and aridic boarder on mesic, respectively. Studied soils developed on hornblendite rocks that are ultrabasic rocks with SiO2 less than 45% and contain ferromagnesian minerals. A toposequence was selected and, three soil profiles on shoulder, backslope and footslope geomorphic positions were described acoording to key to soil taxonmy 2014 and the soil horizons were sampled. Air-dried samples were passed through 2 mm sieve and were used for laboratory analysis. Pseudo-total concentrations of Ni, Cr and Mn were extracted by aqua regia digestion procedure. Free iron oxides (Fed and amorphous iron oxides (Feo were extracted by

Mixed oxides obtained from Co and Mn containing layered double hydroxides: Preparation, characterization, and catalytic properties

International Nuclear Information System (INIS)

Kovanda, Frantisek; Rojka, Tomas; Dobesova, Jana; Machovic, Vladimir; Bezdicka, Petr; Obalova, Lucie; Jiratova, Kveta; Grygar, Tomas

2006-01-01

Co-Mn-Al layered double hydroxides (LDHs) with various Co:Mn:Al molar ratios (4:2:0, 4:1.5:0.5, 4:1:1, 4:0.5:1.5, and 4:0:2) were prepared and characterized. Magnesium containing LDHs Co-Mg-Mn (2:2:2), Co-Mg-Mn-Al (2:2:1:1), and Co-Mg-Al (2:2:2) were also studied. Thermal decomposition of prepared LDHs and formation of related mixed oxides were studied using high-temperature X-ray powder diffraction and thermal analysis. The thermal decomposition of Mg-free LDHs starts by their partial dehydration accompanied by shrinkage of the lattice parameter c from ca. 0.76 to 0.66 nm. The dehydration temperature of the Co-Mn-Al LDHs decreases with increasing Mn content from 180 deg. C in Co-Al sample to 120 deg. C in sample with Co:Mn:Al molar ratio of 4:1.5:0.5. A subsequent step is a complete decomposition of the layered structure to nanocrystalline spinel, the complete dehydration, and finally decarbonation of the mixed oxide phase. Spinel-type oxides were the primary crystallization products. Mg-containing primary spinels had practically empty tetrahedral cationic sites. A dramatic increase of the spinel cell size upon heating and analysis by Raman spectroscopy revealed a segregation of Co-rich spinel in Co-Mn and Co-Mn-Al specimens. In calcination products obtained at 500 deg. C, the spinel mean coherence length was 5-10 nm, and the total content of the X-ray diffraction crystalline portion was 50-90%. These calcination products were tested as catalysts in the total oxidation of ethanol and decomposition of N 2 O. The catalytic activity in ethanol combustion was enhanced by increasing (Co+Mn) content while an optimum content of reducible components was necessary for high activity in N 2 O decomposition, where the highest conversions were found for calcined Co-Mn-Al sample with Co:Mn:Al molar ratio of 4:1:1

Structural phase transition at the percolation threshold in epitaxial (La0.7Ca0.3MnO3)1-x:(MgO)x nanocomposite films.

Science.gov (United States)

Moshnyaga, V; Damaschke, B; Shapoval, O; Belenchuk, A; Faupel, J; Lebedev, O I; Verbeeck, J; van Tendeloo, G; Mücksch, M; Tsurkan, V; Tidecks, R; Samwer, K

2003-04-01

'Colossal magnetoresistance' in perovskite manganites such as La0.7Ca0.3MnO3 (LCMO), is caused by the interplay of ferro-paramagnetic, metal-insulator and structural phase transitions. Moreover, different electronic phases can coexist on a very fine scale resulting in percolative electron transport. Here we report on (LCMO)1-x:(MgO)x (0 strain. The largest colossal magnetoresistance of 10(5)% was observed at the percolation threshold in the conductivity at xc 0.3, which is coupled to a structural phase transition from orthorhombic (0 < x < or 0.1) to rhombohedral R3c structure (0.33 < or = x < or = 0.8). An increase of the Curie temperature for the Rc phase was observed. These results may provide a general method for controlling the magnetotransport properties of manganite-based composite films by appropriate choice of the second phase.

Heavy metals in vegetables sold in the local market in Jordan.

Science.gov (United States)

Osaili, Tareq M; Al Jamali, Abbas F; Makhadmeh, Ibrahim M; Taha, Mohammad; Jarrar, Sukiena K

2016-09-01

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009-0.275 mg kg(-1) wet weight, 0.004-0.060 mg kg(-1), 0.003-0.401 mg kg(-1), 0.105-3.51 mg kg(-1), 0.15-1.15 mg kg(-1), 0.93-14.39 mg kg(-1), 0.044-0.702 mg kg(-1), 0.072-0.289 mg kg(-1) and 2.23-6.65 mg kg(-1), respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.

Lithium adsorptive properties of a new selective adsorbent derived from Li1.33Mn1.67O4

International Nuclear Information System (INIS)

Miyai, Yoshitaka; Ooi, Kenta; Nishimura, Tomonobu; Kumamoto, Jyunji.

1994-01-01

A new selective adsorbent was prepared by the acid treatment of Li 1.33 Mn 1.67 O 4 with spinel structure, followed by granulation with PVC as a binder. The adsorbent showed the highest capacities for lithium from seawater ; the equilibrium lithium uptakes reached 25.5 mg·g -1 by the powdered adsorbent and 18 mg·g -1 by the granulated one at 25degC. The column adsorption study with the granulated adsorbent (diameter 0.7-1.4mm) showed that the lithium uptake reached about 14 mg·g -1 by passing seawater for 30 days. This lithium content is nearly equal to that of lithium ore. Although the lithium adsorption capacity of the granulated adsorbent decreased slightly by repeating the adsorption-desorption cycle, it kept a high capacity as well as a high strength abrasion during the repetition of 10 cycles. (author)

Efficacy and safety of intravenous alteplase at 0.6 mg/kg more than 3 h after acute middle cerebral artery occlusion in patients selected using perfusion-diffusion mismatch

International Nuclear Information System (INIS)

Nakashima, Kazuya; Ohnishi, Hideyuki; Taomoto, Katsushi; Kuga, Yoshihiro; Kodama, Yuuji; Kubota, Hisashi; Tominaga, Takashi; Hayashi, Masato; Miyata, Shiro

2011-01-01

Thrombolytic treatment with alteplase at 0.6 mg/kg is approved for use within 3 h of stroke onset in Japan. Thus, only a small percentage of patients can benefit. A meta-analysis and more recent studies suggest a benefit to patients beyond 3 h with alteplase at 0.9 mg/kg or desmoteplase. We assessed the efficacy and safety of intravenous alteplase at 0.6 mg/kg more than 3 h after stroke onset in patients with acute MCA occlusion who were selected using perfusion-diffusion mismatch. Patients with MCA occlusion eligible for intravenous alteplase within 3 h were selected using MRI (diffusion-weighted (DW), fluid-attenuated inversion recovery (FLAIR), T2*, T2)/MR angiography (MRA) and beyond 3 h using evidence of perfusion-diffusion mismatch. Recanalization was evaluated using MRA within 24 h after treatment. Baseline characteristics, recanalization rates, early and late good clinical outcomes (National Institute of Health Stroke Scale (NIHSS) scores of 0 to 1 or 8-points or greater improvement at 24 h and mRS scores of 0 or 1 on the 90th day), symptomatic intracranial hemorrhage (within 72 h) and mortality (at the 90th day) were evaluated for both groups. Also for both groups, the relationships between recanalization and early and late good clinical outcomes were evaluated. 63 patients with MCA occlusion were treated using intravenous alteplase within 3 h (n=53) and beyond 3 h (n=10). No statistically significant differences were found between the two groups for recanalization rates (52.8 vs. 70.0%), early and late good clinical outcomes (early: 41.5 vs. 60.0%, late: 37.7 vs. 50.0%), symptomatic intracranial hemorrhage (0 vs. 0%), or mortality (1.9 vs. 0%). Our data suggest that intravenous alteplase at 0.6 mg/kg beyond 3 h after MCA occlusion for patients selected using perfusion-diffusion mismatch has the same efficacy and safety as treatment within 3 h. However, a larger sample size is needed to evaluate the relationship between recanalization and clinical outcomes

Phase control of Mn-based spinel films via pulsed laser deposition

International Nuclear Information System (INIS)

Feng, Zhenxing; Chen, Xiao; Fister, Timothy T.; Bedzyk, Michael J.; Fenter, Paul

2016-01-01

Phase transformations in battery cathode materials during electrochemical-insertion reactions lead to capacity fading and low cycle life. One solution is to keep the same phase of cathode materials during cation insertion-extraction processes. Here, we demonstrate a novel strategy to control the phase and composition of Mn-based spinel oxides for magnesium-ion battery applications through the growth of thin films on lattice-matched substrates using pulsed laser deposition. Materials at two extreme conditions are considered: fully discharged cathode MgMn_2O_4 and fully charged cathode Mn_2O_4. The tetragonal MgMn_2O_4 (MMO) phase is obtained on MgAl_2O_4 substrates, while the cubic MMO phase is obtained on MgO substrates. Similarly, growth of the empty Mn_2O_4 spinel in the cubic phase is obtained on an MgO substrate. These results demonstrate the ability to control separately the phase of spinel thin films (e.g., tetragonal vs. cubic MMO) at nominally fixed composition, and to maintain a fixed (cubic) phase while varying its composition (MgxMn_2O_4, for x = 0, 1). As a result, this capability provides a novel route to gain insights into the operation of battery electrodes for energy storage applications.

Flexible all-solid-state asymmetric supercapacitors based on free-standing carbon nanotube/graphene and Mn3O4 nanoparticle/graphene paper electrodes.

Science.gov (United States)

Gao, Hongcai; Xiao, Fei; Ching, Chi Bun; Duan, Hongwei

2012-12-01

We report the design of all-solid-state asymmetric supercapacitors based on free-standing carbon nanotube/graphene (CNTG) and Mn(3)O(4) nanoparticles/graphene (MG) paper electrodes with a polymer gel electrolyte of potassium polyacrylate/KCl. The composite paper electrodes with carbon nanotubes or Mn(3)O(4) nanoparticles uniformly intercalated between the graphene nanosheets exhibited excellent mechanical stability, greatly improved active surface areas, and enhanced ion transportation, in comparison with the pristine graphene paper. The combination of the two paper electrodes with the polymer gel electrolyte endowed our asymmetric supercapacitor of CNTG//MG an increased cell voltage of 1.8 V, a stable cycling performance (capacitance retention of 86.0% after 10,000 continuous charge/discharge cycles), more than 2-fold increase of energy density (32.7 Wh/kg) compared with the symmetric supercapacitors, and importantly a distinguished mechanical flexibility.

Nanocrystalline spinel ferrite (MFe{sub 2}O{sub 4}, M = Ni, Co, Mn, Mg, Zn) powders prepared by a simple aloe vera plant-extracted solution hydrothermal route

Energy Technology Data Exchange (ETDEWEB)

Phumying, Santi; Labuayai, Sarawuth; Swatsitang, Ekaphan; Amornkitbamrung, Vittaya [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand); Maensiri, Santi, E-mail: santimaensiri@gmail.com [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)

2013-06-01

Graphical abstract: This figure shows the specific magnetization curves of the as-prepared MFe{sub 2}O{sub 4} (M = Ni, Co, Mn, Mg, Zn) powders obtained from room temperature VSM measurement. These curves are typical for a soft magnetic material and indicate hysteresis ferromagnetism in the field ranges of ±500 Oe, ±1000 Oe, and ±2000 Oe for the CoFe{sub 2}O{sub 4}, MgFe{sub 2}O{sub 4} and MnFe{sub 2}O{sub 4} respectively, whereas the samples of NiFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} show a superparamagnetic behavior. Highlights: ► Nanocrystalline MFe{sub 2}O{sub 4} powders were synthesized by a novel hydrothermal method. ► Metal acetylacetonates and aloe vera plant-extracted solution are used. ► This biosynthetic route is very simple and provides high-yield oxide nanomaterials. ► XRD and TEM results indicate that the prepared samples have only spinel structure. ► The maximum M{sub s} of 68.9 emu/g at 10 kOe were observed for the samples of MnFe{sub 2}O{sub 4}. - Abstract: Nanocrystalline spinel ferrite MFe{sub 2}O{sub 4} (M = Ni, Co, Mn, Mg, Zn) powders were synthesized by a novel hydrothermal method using Fe(acac){sub 3}, M(acac){sub 3} (M = Ni, Co, Mn, Mg, Zn) and aloe vera plant extracted solution. The X-ray diffraction and selected-area electron diffraction results indicate that the synthesized nanocrystalline have only spinel structure without the presence of other phase impurities. The crystal structure and morphology of the spinel ferrite powders, as revealed by TEM, show that the NiFe{sub 2}O{sub 4} and CoFe{sub 2}O{sub 4} samples contain nanoparticles, whereas the MnFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4} samples consist of many nanoplatelets and nanoparticles. Interestingly, the ZnFe{sub 2}O{sub 4} sample contains plate-like structure of networked nanocrystalline particles. Room temperature magnetization results show a ferromagnetic behavior of the CoFe{sub 2}O{sub 4}, MnFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4} samples, whereas the

Ultrasound assisted synthesis of Mn3O4 nanoparticles anchored graphene nanosheets for supercapacitor applications

International Nuclear Information System (INIS)

Raj, Balasubramaniam Gnana Sundara; Ramprasad, Rajasekharan Nair Radhika; Asiri, Abdullah M.; Wu, Jerry J; Anandan, Sambandam

2015-01-01

Highlights: • Room temperature synthesis of Mn 3 O 4 –graphene (MG) composite via ultra sound assisted method. • TEM images shows Mn 3 O 4 nanoparticles are uniformly distributed on the surface of graphene nanosheets. • MG composite exhibited high specific capacitance of 312 F g −1 in 1 M Na 2 SO 4 which was three times greater than pristine Mn 3 O 4 . • 76% of the initial capacitance was retained even after 1000 cycles. • The higher specific capacitance of the MG nanocomposite due to the synergistic effect between the Mn 3 O 4 nanoparticles and graphene nanosheets. - Abstract: Mn 3 O 4 nanoparticles anchored graphene nanosheets (MG) have been successfully synthesized by a simple ultrasound assisted synthesis at room temperature without the use of any templates or surfactants for supercapacitor applications. Upon ultrasound assisted synthesis, the formation of Mn 3 O 4 nanoparticles and the graphene oxide reduction occurs simultaneously. The crystalline structure of thus prepared MG nanocomposite have been characterized by the powder X-ray diffraction (XRD) analysis. Thermo Gravimetric Analysis (TGA) is used to determine the mass content of graphene (17 wt%) in the MG nanocomposite. Transmission electron microscopy (TEM) and Atomic force microscopy (AFM) studies shows that the Mn 3 O 4 nanoparticles (4–8 nm) were uniformly anchored on the surface of graphene nanosheets. The electrochemical properties of the MG nanocomposite were investigated by employing cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). The capacitive properties of MG nanocomposite studied in the presence of 1 M Na 2 SO 4 exhibited high specific capacitance of 312 F g −1 which was approximately three times greater than that of pristine Mn 3 O 4 (113 F g −1 ) at the same current density of 0.5 mA cm −2 in the potential range from -0.1 to +0.9 V. About 76% of the initial capacitance was retained even after 1000 cycles

Application of atomic absorption spectrophotometry to determine Cd, Cu, Pb, Zn,...in vegetable samples in Dalat

Energy Technology Data Exchange (ETDEWEB)

Giang, Nguyen; Tam, Nguyen Thanh; Ngoc Trinh, Le Thi; Mai, Truong Phuong; Minh, Nguyen Van [Nuclear Research Institute, Dalat (Viet Nam)

2004-08-01

Nowadays atomic absorption spectrometry has become valuable method for trace element analysis because high specificity; low detection litmus, easy to use; easy sample preparation, low investment and running costs... atomic absorption spectrometry is generally accepted as one the most suitable method for single - element analysis of trace elements in various kinds of materiel. In 2003, we applied flame - atomic absorption spectrometry for analyzing Ca, Cd, Cu, Pb, Zn...in vegetables and their extracted juices were collected form 11 locations of Dalat, including two kinds of vegetables (goods and safety) in both the summer and winter. Average concentration of Ca = 240 mg/kg wet, Cd = 0.035 mg/kg wet, Cu = 0.67 mg/kg wet, Mg = 131 mg/kg wet, Fe = 8.1/kg wet, Mn = 3.1/kg wet, Na = 3266 mg/kg wet, Pb = 0.345 mg/kg wet and Zn = 3.3 mg wet. In their extracted juices: Ca = 89 mg/kg wet, Cd = 0.008 mg/kg wet, Cu = 0.19 mg/kg wet, Mg = 43 mg/kg wet, Fe = 2.3 mg/kg wet, Mn = 0.61 mg/kg wet, Na = 971 mg/kg wet, Pb = 0.107 mg/kg wet and Zn = 0.65 mg/kg wet. (author)

Application of atomic absorption spectrophotometry to determine Cd, Cu, Pb, Zn,...in vegetable samples in Dalat

International Nuclear Information System (INIS)

Nguyen Giang; Nguyen Thanh Tam; Le Thi Ngoc Trinh; Truong Phuong Mai; Nguyen Van Minh

2004-01-01

Nowadays atomic absorption spectrometry has become valuable method for trace element analysis because high specificity; low detection litmus, easy to use; easy sample preparation, low investment and running costs... atomic absorption spectrometry is generally accepted as one the most suitable method for single - element analysis of trace elements in various kinds of materiel. In 2003, we applied flame - atomic absorption spectrometry for analyzing Ca, Cd, Cu, Pb, Zn...in vegetables and their extracted juices were collected form 11 locations of Dalat, including two kinds of vegetables (goods and safety) in both the summer and winter. Average concentration of Ca = 240 mg/kg wet, Cd = 0.035 mg/kg wet, Cu = 0.67 mg/kg wet, Mg = 131 mg/kg wet, Fe = 8.1/kg wet, Mn = 3.1/kg wet, Na = 3266 mg/kg wet, Pb = 0.345 mg/kg wet and Zn = 3.3 mg wet. In their extracted juices: Ca = 89 mg/kg wet, Cd = 0.008 mg/kg wet, Cu = 0.19 mg/kg wet, Mg = 43 mg/kg wet, Fe = 2.3 mg/kg wet, Mn = 0.61 mg/kg wet, Na = 971 mg/kg wet, Pb = 0.107 mg/kg wet and Zn = 0.65 mg/kg wet. (author)

Twiny pro: 5.1 kg of propane dressed in apple green; Twiny pro: 5.1 kg de propane en habillage vert pomme

Energy Technology Data Exchange (ETDEWEB)

Anon.

1998-05-01

Designed for professional and outdoors uses, Twini Pro - the new Primagaz 5.1 kg propane cylinder - is a complement to the Twiny butane 6 kg cylinder was launched during the first week of March in some 2,500 outlets, before 5,000 and 7,000 points later

Determination of Na, Cl, Ca, Mg, Mn and K in milk samples by activation analysis

International Nuclear Information System (INIS)

Kira, Carmen S.; Maihara, Vera A.

2000-01-01

In the present work cow milk samples distributed for Sao Paulo government institutions, by means of the 'Viva leite' programme, have been monitored. The concentrations of Ca, Cl, K, Mg, Mn and Na were determined in five milk samples and in three different kinds of commercial powder milk, by instrumental neutron activation. For quality control, the reference materials NIST whole milk powder and non fat milk powder were analysed. The results obtained are in the range of the concentrations mentioned in the literature for these elements. (author)

The Effect of Different Levels of Cu, Zn and Mn Nanoparticles in Hen Turkey Diet on the Activity of Aminopeptidases.

Science.gov (United States)

Jóźwik, Artur; Marchewka, Joanna; Strzałkowska, Nina; Horbańczuk, Jarosław Olav; Szumacher-Strabel, Małgorzata; Cieślak, Adam; Lipińska-Palka, Paulina; Józefiak, Damian; Kamińska, Agnieszka; Atanasov, Atanas G

2018-05-11

The aim of the study was to estimate the influence of the different levels of Cu, Zn, and Mn nanoparticles on the activity of aminopeptidases in turkey. An experiment was carried out on 144 turkey hen Hybrid Converter. The birds were divided into groups given standard- and nanoparticle-supplementation of different level of copper (Cu 20, 10, 2 mg/kg), zinc (Zn 100, 50, 10 ppm), and manganese (Mn 100, 50, 10 ppm), covering respectively 100%, 50%, and 10% of the physiological demands for those minerals in the diet. The activity of aminopeptidases (alanyl: AlaAP, leucyl: LeuAP and arginyl: ArgAP) after supplementation of minerals was determined in the breast and thigh turkey muscle. The strongest effect of interaction among minerals supplementation form and dose on the activity levels of the aminopeptidases in thigh muscle was observed for nano-Cu already at the lowest dose of 2 mg/kg. In this dose (covering 10% of the birds’ demand) nano form of supplementation significantly increased the activity of Ala-, Leu-, and ArgAP (877, 201, and 719, respectively), compared to standard form of supplementation (461, 90.5, and 576, respectively). In turn, in breast muscle, after supplementation covering 10% of the demand with the nano-Cu, nano-Zn, and nano-Mn compared to the standard form, we did not observe any significant difference in the activity levels of any of the investigated aminopeptidases, except for AlaAP under Zn supplementation. Supplementation with the 20 mg/kg of Nano-Cu (100% of demand) and with 10 mg/kg of Nano-Cu (50% of demand) inhibited the activity of all of the three aminopeptidases in thigh muscle. Supplementation of the minerals in nano form into the diet, especially of Cu and Zn in the dose covering 10% of the demand is relevant to maintain homeostasis in turkey muscles, as indicated by the activity of the aminopeptidases.

NMR-based metabonomic analysis of MnO-embedded iron oxide nanoparticles as potential dual-modal contrast agents

Science.gov (United States)

Li, Jinquan; Zhou, Zijian; Feng, Jianghua; Cai, Shuhui; Gao, Jinhao; Chen, Zhong

2014-05-01

MnO-embedded iron oxide nanoparticles (MnIO-NPs) can be treated as potential dual-modal contrast agents. However, their overall bio-effects and potential toxicity remain unknown. In this study, the metabolic effects of MnIO-NPs (dosed at 1 and 5 mg Fe/kg) on Sprague-Dawley rats were investigated using metabonomic analysis, histopathological examination, and conventional biochemical analysis. The histological changes included a focal inflammation in the liver at high-dose and a slightly enlarged area of splenic white pulp after 48 h post-dose. Blood biochemical analysis showed that albumin, globulins, aspartate aminotransferase, lactate dehydrogenase, blood urea nitrogen, and glucose changed distinctly compared to the control. The metabonomic analysis of body fluids (serum and urine) and tissues (liver, kidney, and spleen) indicated that MnIO-NPs induced metabolic perturbation in rats including energy, nucleotides, amino acids and phospholipid metabolisms. Besides, the variations of supportive nutrients: valine, leucine, isoleucine, nicotinamide adenine dinucleotide (phosphate), and nicotinamide, and the conjugation substrates: glycine, taurine, glutamine, glutathione, and methyl donors (formate, sarcosine, dimethylglycine, choline, and betaine) were involved in detoxification reaction of MnIO-NPs. The obtained information would provide identifiable ground for the candidate selection and optimization.

Dose of rocuronium for rapid tracheal intubation following remifentanil 2 μg kg-1 and propofol 2 mg kg-1.

Science.gov (United States)

Oh, Ah-Young; Cho, Suk-Ju; Seo, Kwang-Suk; Ryu, Jung-Hee; Han, Sung-Hee; Hwang, Jung-Won

2013-09-01

Full relaxation is not mandatory for successful tracheal intubation. We tried to find the dose of rocuronium that gave acceptable intubation conditions in a rapid sequence intubation with remifentanil and propofol. A dose-finding study of rocuronium using a modified Dixon's up-and-down method. A single tertiary care teaching hospital. Patients undergoing elective surgery under general anaesthesia. After premedication with midazolam and glycopyrrolate, anaesthesia was induced using remifentanil 2 μg kg and propofol 2 mg kg, and a predetermined dose of rocuronium was administered. The dose of rocuronium was determined by a modified Dixon's up-and-down method starting from 0.8 mg kg with an interval of 0.1 or 0.05 mg kg. Intubation was performed 60 s after the start of the rocuronium injection. Intubation conditions were graded as excellent, good or poor. Excellent or good were regarded as clinically acceptable. A dose of rocuronium needed for acceptable intubation condition in 50% of patients (ED50) during rapid tracheal intubation after induction of anaesthesia with remifentanil and propofol. Twenty-eight patients were enrolled to obtain six crossovers. The ED50 of rocuronium was 0.20 mg kg (95% confidence interval, CI 0.17 to 0.23 mg kg) by a modified Dixon's up-and-down method. After induction of anaesthesia with remifentanil 2 μg kg and propofol 2 mg kg, the ED50 of rocuronium for acceptable intubation condition was 0.20 mg kg (95% CI, 0.17 to 0.23 mg kg) for rapid sequence intubation. Thus, we recommend that the intubation dose should be 0.8 mg kg. Clinical trial registration KCT0000094.

DyNi{sub 2}Mn-magnetisation and Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Wang Jianli; Campbell, Stewart James, E-mail: stewart.campbell@adfa.edu.au [University of New South Wales, School of Physical, Environmental and Mathematical Sciences (Australia); Kennedy, Shane Joseph [ANSTO, Bragg Institute (Australia); Dou Shixue [University of Wollongong, Institute for Superconductivity and Electronic Materials (Australia); Wu Guangheng [Chinese Academy of Science, Institute of Physics (China)

2012-03-15

The physical properties of DyNi{sub 2}Mn doped with {sup 57}Fe have been investigated by X-ray diffraction, magnetisation (10-300 K) and {sup 57}Fe Moessbauer spectroscopy measurements (5-300 K). DyNi{sub 2}Mn({sup 57}Fe) crystallizes in the MgCu{sub 2}-type cubic structure (Fd{sup }-3m space group). The ordering temperature is found to be T{sub C} = 99(2) K, much higher than those of DyNi{sub 2} ({approx}22 K) and DyMn{sub 2} ({approx}35 K). Analyses of isothermal M-H curves and the related Arrott plots confirm that the magnetic phase transition at T{sub C} is second order. The magnetic entropy change around T{sub C} is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The spectra above T{sub C} exhibit features consistent with quadrupolar effects while below T{sub C} the spectra exhibit magnetic hyperfine splitting. The Debye temperature for DyNi{sub 2}Mn has been determined as {theta}{sub D} = 200(20) K from a fit to the variable temperature isomer shift IS(T).

Magnetization of correlated electron systems. MnSi thin films, CrB2 single crystals and two-dimensional electron systems in MgZnO/ZnO

International Nuclear Information System (INIS)

Brasse, Matthias

2014-01-01

Torque magnetometry at low temperature is performed to investigate the magnetic properties of MnSi thin films, of a CrB 2 single crystal and of a two-dimensional electron system (2DESs) formed at the interface of MgZnO/ZnO. The magnetic anisotropy and phase diagram of MnSi as well as information on the electronic structure of CrB 2 are obtained. The MgZnO/ZnO 2DESs exhibits the de Haas-van Alphen effect and non-equilibrium currents which are analyzed in order to determine ground state properties and excited states, respectively.

[Comparison of 1 mg/body and 3 mg/body of intravenous granisetron for the prevention of chemotherapy-induced nausea and vomiting and adverse events in hematological malignancy patients].

Science.gov (United States)

Motohashi, Shinya; Hori, Katsuhito; Ono, Takaaki; Ohnishi, Kazunori; Kawakami, Junichi

2012-01-01

Granisetron is a selective 5-hydroxy tryptamine3 receptor antagonist and widely used for chemotherapy-induced nausea and vomiting (CINV). Recommended dose of intravenous granisetron in the USA and Europe has been set at 0.01 mg/kg (1 mg/body) in the antiemetic treatment guidelines established by the American Society of Clinical Oncology and National Comprehension Cancer Network. In contrast, the approved dose in Japan is 0.04 mg/kg (3 mg/body). Randomized controlled trials (RCTs) which compared 1 mg/body with 3 mg/body of intravenous granisetron for CINV had been reported in Japan. In these RCTs, however, hematological malignancy patients were excluded. We performed observational retrospective study to compare 1 mg/body with 3 mg/body of intravenous granisetron for the prevention of CINV and adverse events in hematological malignancy patients. Number of the patients and chemotherapy courses were 15 and 30 in the 1 mg/body group, and 15 and 27 in the 3 mg/body group, respectively. No nausea rates in the 1 and 3 mg/body group were 83% and 89% of courses, respectively. No vomiting rates in the 1 and 3 mg/body group were 97% and 100% of courses, respectively. The incidences of constipation in the 1 and 3 mg/body group were 34% and 45% of courses, respectively. Anaphylaxis and headache did not occur in both groups. Our findings suggested that 1 mg/body of intravenous granisetron can prevent from CINV in hematological malignancy patients, as well as 3 mg/body.

Photoluminescence properties of whitlockite-type Ca{sub 9}MgK(PO{sub 4}){sub 7}:Eu{sup 2+},Mn{sup 2+} phosphor

Energy Technology Data Exchange (ETDEWEB)

Guo, Ning, E-mail: guoning@usst.edu.cn [Department of Chemistry, University of Shanghai for Science and Technology, Shanghai 200093 (China); Li, Shuo; Chen, Jishen; Li, Jing; Zhao, Yuefeng; Wang, Lu; Jia, Chengzheng; Ouyang, Ruizhuo [Department of Chemistry, University of Shanghai for Science and Technology, Shanghai 200093 (China); Lü, Wei [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2016-11-15

Novel single-phased Eu{sup 2+}/Mn{sup 2+}-coactivated whitlockite-type Ca{sub 9}MgK(PO{sub 4}){sub 7} phosphors which can emit white light upon UV light excitation, are prepared by the solid-state method, and their luminescence properties are systematically investigated via a combination of X-ray powder diffraction and spectroscopy measurements. For Eu{sup 2+}–Mn{sup 2+} codoped samples, an efficient energy transfer process can takes place and its mechanism is a resonant type via a dipole-quadrupole interaction which can be elucidated by DexterГ—Віs theoretical model. Following the principle of energy transfer, myriad luminescence colors with a large gamut from blue to purplish red and across white zone in a line in the chromaticity diagram of the CIE can be obtained by simply adjusting the concentration ratio of Eu{sup 2+} to Mn{sup 2+}. Photoluminescence spectra reveal that the white color emission is originated from the combination of two emission bands of Eu{sup 2+} and Mn{sup 2+} ions. Additionally, their CIE chromaticity coordinates and correlated color temperatures (CCT) have been calculated and discussed in detail. The luminescence suggest that whitlockite-type phosphor, Ca{sub 9}MgK(PO{sub 4}){sub 7}, co-activated with europium and manganese, is a promising single-phased white-emitting candidate for use in ultraviolet-chip-based white LEDs.

Optical absorption spectra and g factor of MgO: Mn2+explored by ab initio and semi empirical methods

Science.gov (United States)

Andreici Eftimie, E.-L.; Avram, C. N.; Brik, M. G.; Avram, N. M.

2018-02-01

In this paper we present a methodology for calculations of the optical absorption spectra, ligand field parameters and g factor for the Mn2+ (3d5) ions doped in MgO host crystal. The proposed technique combines two methods: the ab initio multireference (MR) and the semi empirical ligand field (LF) in the framework of the exchange charge model (ECM) respectively. Both methods of calculations are applied to the [MnO6]10-cluster embedded in an extended point charge field of host matrix ligands based on Gellé-Lepetit procedure. The first step of such investigations was the full optimization of the cubic structure of perfect MgO crystal, followed by the structural optimization of the doped of MgO:Mn2+ system, using periodic density functional theory (DFT). The ab initio MR wave functions approaches, such as complete active space self-consistent field (CASSCF), N-electron valence second order perturbation theory (NEVPT2) and spectroscopy oriented configuration interaction (SORCI), are used for the calculations. The scalar relativistic effects have also been taken into account through the second order Douglas-Kroll-Hess (DKH2) procedure. Ab initio ligand field theory (AILFT) allows to extract all LF parameters and spin-orbit coupling constant from such calculations. In addition, the ECM of ligand field theory (LFT) has been used for modelling theoptical absorption spectra. The perturbation theory (PT) was employed for the g factor calculation in the semi empirical LFT. The results of each of the aforementioned types of calculations are discussed and the comparisons between the results obtained and the experimental results show a reasonable agreement, which justifies this new methodology based on the simultaneous use of both methods. This study establishes fundamental principles for the further modelling of larger embedded cluster models of doped metal oxides.

Cooled optically stimulated luminescence in CaF2:Mn

International Nuclear Information System (INIS)

Miller, S.D.; Endres, G.W.R.; McDonald, J.C.; Swinth, K.L.

1988-01-01

A new optically stimulated luminescence technique has been developed for the readout of CaF 2 :Mn thermoluminescent material. Minimum detectable gamma exposures may potentially be measured at 10 nC.kg -1 using the 254 nm line of a mercury lamp. Additional studies were done on CaF 2 :Mn using 351 nm excimer laser stimulation. (author)

Ferri-magnetic order in Mn induced spinel Co_3_−_xMn_xO_4 (0.1≤x≤1.0) ceramic compositions

International Nuclear Information System (INIS)

Meena, P.L.; Sreenivas, K.; Singh, M.R.; Kumar, Ashok; Singh, S.P.; Kumar, Ravi

2016-01-01

We report structural and magnetic properties of spinel Co_3_−_xMn_xO_4 (x=0.1–1.0) synthesized by solid state reaction technique. Rietveld refinement analysis of X-ray diffraction (XRD) data, revealed the formation of polycrystalline single phase Co_3_−_xMn_xO_4 without any significant structural change in cubic crystal symmetry with Mn substitution, except change in lattice parameter. Temperature dependent magnetization data show changes in magnetic ordering temperature, indicating formation of antiferromagnetic (AFM) and ferrimagnetic (FM) phase at low Mn concentration (x≤0.3) and well-defined FM phase at high Mn concentration (x≥0.5). The isothermal magnetization records established an AFM/FM mixed phase for composition ranging 0.1 0.5. - Highlights: • Synthesis of single phase polycrystalline Co_3_−_xMn_xO_4 ceramic. • Change in magnetic ordering with varying Mn concentration. • The complex spin distribution is contributing to FM ordering with higher Mn.

Local Structure of Mn in (La1-xHox)2/3Ca1/3MnO3 Studied by X-ray Absorption Fine Structure

International Nuclear Information System (INIS)

Pietnoczka, A.; Bacewicz, R.; Antonowicz, J.; Zalewski, W.; Pekala, M.; Drozd, V.; Fagnard, J.F.; Vanderbemden, P.

2010-01-01

Results of X-ray absorption fine structure measurements in manganites (La 1-x Ho x ) 2/3 Ca 1/3 MnO 3 with 0.15 3 is doped with a divalent element such as Ca 2+ , substituting for La 3+ , holes are induced in the filled Mn d orbitals. This leads to a strong ferromagnetic coupling between Mn sites. Ca ions in La 1-x Ca x MnO 3 introduce a distortion of the crystal lattice and mixed valence Mn ions (Mn 3+ and Mn 4+ ). On the other hand, in manganites (La 1-x Ho x ) 2/3 Ca 1/3 MnO 3 the substitution of La for Ho causes a lattice distortion and induces a disorder, which reduces a magnetic interaction. The ferromagnetic transition temperature and conductivity decrease very quickly with increasing x. The magnetic and transport properties of compounds depend on the local atomic structure around Mn ions. The information on the bond lengths and Debye-Waller factor are obtained from the extended X-ray absorption fine structure (EXAFS) data analysis. The charge state of Mn is determined from the position of the absorption edge in X-ray absorption near edge structure (XANES) data. XAFS results are in good agreement with magnetic characteristics of the studied materials. (authors)

Brain regional distributions of the minor and trace elements, Na, Mg, Cl, K, Mn, Zn, Rb and Br, in young and aged mice

International Nuclear Information System (INIS)

Amano, R.; Oishi, S.; Ishie, M.; Kimura, M.

2001-01-01

Brain regional cerebral concentrations of minor and trace elements, Na, Mg, Cl, K, Mn, Zn, Rb and Br were determined in young and aged mice, by instrumental neutron activation analysis for small amounts of regional (corpus striatum, cerebellum, cerebral cortex, hippocampus, midbrain, pons and medulla olfactory bulb) samples. Significant age-related differences were found for Mn concentration in all brain regions: The Mn concentration of the young brain was higher than those of aged brain, in addition, Zn was distributed heterogeneously, and highly concentrated in cerebral cortex and hippocampus regions in both young and aged mice. These results suggest that, in the aged brain, Mn is required less than in the young brain, on the other hand, Zn is required equally in both young and aged brains. (author)

Immobilization of Mn and NH4 (+)-N from electrolytic manganese residue waste.

Science.gov (United States)

Chen, Hongliang; Liu, Renlong; Liu, Zuohua; Shu, Jiancheng; Tao, Changyuan

2016-06-01

The objective of this work was the immobilization of soluble manganese (Mn) and ammonium nitrogen (NH4 (+)-N) leached from electrolytic manganese residue (EMR). Immobilization of Mn was investigated via carbonation using carbon dioxide (CO2) and alkaline additives. NH4 (+)-N immobilization was evaluated via struvite precipitation using magnesium and phosphate sources. Results indicated that the immobilization efficiency of Mn using CO2 and quicklime (CaO) was higher than using CO2 and sodium hydroxide (NaOH). This higher efficiency was likely due to the slower release of OH(-) during CaO hydrolysis. The immobilization efficiency of Mn was >99.99 % at the CaO:EMR mass ratio of 0.05:1 for 20-min reaction time. The struvite precipitation of NH4 (+)-N was conducted in the carbonated EMR slurry and the immobilization efficiency was 89 % using MgCl2 · 6H2O + Na3PO4 · 12H2O at the Mg:P:N molar ratio of 1.5:1.5:1 for 90-min reaction time. A leaching test showed that the concentrations of Mn and NH4 (+)-N in the filtrate of the treated EMR were 0.2 and 9 mg/L, respectively. The combined immobilization of Mn and NH4 (+)-N was an effective pretreatment method in the harmless treatment of the EMR.

Manganese-induced regulations in growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in fragrant rice.

Science.gov (United States)

Li, Meijuan; Ashraf, Umair; Tian, Hua; Mo, Zhaowen; Pan, Shenggang; Anjum, Shakeel Ahmad; Duan, Meiyang; Tang, Xiangru

2016-06-01

Micro-nutrient application is essential for normal plant growth while a little is known about manganese (Mn)-induced regulations in morpho-physiological attributes, aroma formation and enzyme involved in 2-acetyl-1-pyrroline (2-AP) biosynthesis in aromatic rice. Present study aimed to examine the influence of four levels of Mn i.e., Mn1 (100 mg MnSO4 pot(-1)), Mn2 (150 mg MnSO4 pot(-1)), Mn3 (200 mg MnSO4 pot(-1)), and Mn4 (250 mg MnSO4 pot(-1)) on the growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in two fragrant rice cultivars i.e., Meixiangzhan and Nongxiang 18. Pots without Mn application were served as control (Ck). Each pot contained 15 kg of soil. Effects on agronomic characters, quality attributes, 2-AP contents and enzymes involved in 2-AP biosynthesis have been studied in early and late season rice. Results depicted that Mn improved rice growth, yield and related characters, and some quality attributes significantly. It further up-regulated proline, pyrroline-5-carboxylic acid (P5C) (precursors of 2-AP), soluble proteins and activities of proline dehydrogenase (ProDH), Δ(1) pyrroline-5-carboxylic acid synthetase (P5CS) ornithine aminotransferase (OAT) that led to enhanced 2-AP production in rice grains. Moreover, higher Mn levels resulted in increased grain Mn contents in both rice cultivars. Along with growth and yield improvement, Mn application significantly improved rice aromatic contents. Overall, Nongxiang 18 accumulated more 2-AP contents than Meixiangzhan in both seasons under Mn application. This study further explored the importance of Mn in rice aroma formation and signifies that micro-nutrients can play significant roles in rice aroma synthesis; however, intensive studies at molecular levels are still needed to understand the exact mechanisms of Mn to improve rice aroma formation. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Nutrient concentrations in potato stem, petiole and leaflet in response to potassium fertilizer Teores de nutrientes no caule, pecíolo e limbo da batateira em função da adubação potássica

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Roberto dos Anjos Reis Jr.

2000-06-01

Full Text Available Chemical composition of potato stem, petiole and leaflet were evaluated in response to the application of K fertilizer. Potassium was applied at six different rates (0, 60, 120, 240, 480 and 960 kg ha-1 of K2O, as K2SO4 and was placed in the furrow during planting. Two plants per plot were sampled 48 days after plant emergence to evaluate N, P, K, Ca, Mg, S, Cu, Mn and Zn concentrations in stems, petioles and leaflets of the youngest fully expanded leaf. It is recommended using potato petioles to evaluate the N, P, K, Ca, Mg and Cu status and using potato leaflet to evaluate the S, Mn and Zn status. The stem was not a good indicator of S nutritional status. Petiole N, P and Cu concentrations associated with the maximum tuber yield (30.5 t ha-1, with 353.4 kg ha-1 of K2O were 25.9 g kg-1, 1.4 g kg-1 and 9.7 mg kg-1, respectively, while, the leaflet S, Mn and Zn concentrations associated with the maximum tuber yield were 4.0 g kg-1, 155.2 mg kg-1 and 59.4 mg kg-1, respectively. This information should be used to build data banks of adequate nutrient concentration at different portions of potato plant and like this, to aid the nutrient diagnosis in potato crops.Para avaliar a composição mineral em órgãos da batateira em função da adubação potássica, foi realizado experimento com doses de potássio (0, 60, 120, 240, 480 e 960 kg ha-1 de K2O delineado em blocos casualizados com quatro repetições. Duas plantas por parcela foram amostradas aos 48 dias após emergência das plantas para avaliar teores de N, P, K, Ca, Mg, S, Cu, Mn e Zn no caule, pecíolo e limbo da folha recém madura. Recomenda-se utilizar o pecíolo da batateira para avaliar o status de N, P, K, Ca, Mg e Cu e utilizar o limbo da batateira para avaliar o status de S, Mn e Zn. O caule não foi um bom indicador do estado nutricional em relação ao S. A aplicação de 353,4 kg ha-1 de K2O proporcionou a máxima produtividade de tubérculos (30,5 t ha-1 e teores de N, P e Cu no

Remediation of a historically Pb contaminated soil using a model natural Mn oxide waste.

Science.gov (United States)

McCann, Clare M; Gray, Neil D; Tourney, Janette; Davenport, Russell J; Wade, Matthew; Finlay, Nina; Hudson-Edwards, Karen A; Johnson, Karen L

2015-11-01

A natural Mn oxide (NMO) waste was assessed as an in situ remediation amendment for Pb contaminated sites. The viability of this was investigated using a 10 month lysimeter trial, wherein a historically Pb contaminated soil was amended with a 10% by weight model NMO. The model NMO was found to have a large Pb adsorption capacity (qmax 346±14 mg g(-1)). However, due to the heterogeneous nature of the Pb contamination in the soils (3650.54-9299.79 mg kg(-1)), no treatment related difference in Pb via geochemistry could be detected. To overcome difficulties in traditional geochemical techniques due to pollutant heterogeneity we present a new method for unequivocally proving metal sorption to in situ remediation amendments. The method combines two spectroscopic techniques; namely electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). Using this we showed Pb immobilisation on NMO, which were Pb free prior to their addition to the soils. Amendment of the soil with exogenous Mn oxide had no effect on microbial functioning, nor did it perturb the composition of the dominant phyla. We conclude that NMOs show excellent potential as remediation amendments. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Structural, magnetic and Moessbauer spectral studies of aluminum substituted Mg-Mn-Ni ferrites (Mg{sub 0.2}Mn{sub 0.5}Ni{sub 0.3}Al{sub y}Fe{sub 2-y}O{sub 4})

Energy Technology Data Exchange (ETDEWEB)

Verma, Satish, E-mail: satishapurva@gmail.com [Department of Physics, Govt. P.G. College, Solan-173212 (India); Chand, Jagdish [Department of Physics, Govt. P.G. College, Solan-173212 (India); Batoo, Khalid Mujasam [King Abdullah Institute of Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia); Singh, M. [Department of Physics, Himachal Pradesh University, Summer-Hill, Shimla-171005 (India)

2013-02-25

Highlights: Black-Right-Pointing-Pointer Single phase nanocrystalline Al{sup 3+} ions doped Mg-Mn-Ni ferrite have been synthesized by citrate precursor method. Black-Right-Pointing-Pointer Particle size decreases as non-magnetic Al content increases. Black-Right-Pointing-Pointer The presence of doublets in the Moessbauer spectra can be attributed to superparamagnetic relaxation. - Abstract: Nanocrystalline Al{sup 3+} ions doped Mg{sub 0.2}Mn{sub 0.5}Ni{sub 0.3}Al{sub y}Fe{sub 2-y}O{sub 4} compositions, where y = 0.0, 0.05 and 0.10 have been synthesized by citrate precursor method. Crystal structure and magnetic properties have been investigated at 300 K by means of X-ray diffraction, transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and Moessbauer spectra measurements. XRD study reveals that particle size decreases from 102.25 nm to 41.65 nm. A decrease in lattice constant and saturation magnetization was attributed to smaller ionic radius of Al{sup 3+} ions and weakening of super exchange interaction. Experimental and X-ray density decrease with increasing aluminum concentration. Though Moessbauer spectra of y = 0.0 exhibit normal Zeeman split sextets, spectra of samples for y = 0.05 and 0.10 are characterized by simultaneous presence of a central paramagnetic doublet. Dependence of Moessbauer parameters such as isomer shift, quadrupole splitting, linewidth and hyperfine magnetic field on Al{sup 3+} ions concentration have been discussed. Initial permeability '{mu}{sub i}', saturation magnetization (4 {pi}M{sub S}), retentivity (M{sub R}), Bohr magneton number (n{sub B}{sup N}), magneto crystalline anisotropy constant (K{sub 1}) and magnetic loss decreases while coercivity (H{sub C}) increases with increasing substitution of Al{sup 3+} ions. Magnetic loss has very low value in the range of 10{sup -3} which is two orders of magnitude less than samples prepared by conventional method.

Improving solid-state hydriding and dehydriding properties of the LiBH{sub 4} plus MgH{sub 2} system with the addition of Mn and V dopants

Energy Technology Data Exchange (ETDEWEB)

Crosby, Kyle; Wan, Xuefei; Shaw, Leon L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, 97 North Eagleville Road, U-3136, Storrs, CT 06269 (United States)

2010-11-01

The hydriding process of the 2LiH + MgB{sub 2} mixture is controlled by outward diffusion of Mg and inward diffusion of Li and H within MgB{sub 2} crystals to form LiBH{sub 4}. This study explores the feasibility of using transition metal dopants, such as Mn and V, to enhance the diffusion rate and thus the hydriding kinetics. It is found that Mn can indeed enhance the hydriding kinetics of the 2LiH + MgB{sub 2} mixture, while V does not. The major factor in enhancing the diffusion rate and thus the hydriding kinetics is related to the dopant's ability to induce the lattice distortion of MgB{sub 2} crystals. This study demonstrates that the kinetics of the diffusion controlled solid-state hydriding process can be improved by doping if the dopant is properly selected. (author)

Metal concentrations and toxicity in South African snoek (Thyrsites atun) and yellowtail (Seriola lalandi).

Science.gov (United States)

Bosch, Adina C; O'Neill, Bernadette; Kerwath, Sven E; Sigge, Gunnar O; Hoffman, Louwrens C

2017-09-15

The concentrations of 16 metals were assessed in snoek(Thyrsites atun; n=20) and yellowtail (Seriola lalandi; n=37) sampled from the West and South-East coasts of South Africa. Variability was observed at both small (Al, Cr, Hg, Pb, Mn and Cu) and large (As and Cu) spatial scales while inter-specific examination revealed diverse metal concentrations in snoek (Higher levels: Cr, Mn, Co, Hg and Pb) and yellowtail (higher levels: Fe and Cu). Zn, As and Hg were positively correlated with yellowtail size with no such correlations in snoek. Mean concentrations of As (0.61mg·kg -1 ; 0.98mg·kg -1 ), Cd (0.008mg·kg -1 ; 0.004mg·kg -1 ), Hg (0.27mg·kg -1 ; 0.16mg·kg -1 ) and Pb (0.009mg·kg -1 ; 0.005mg·kg -1 ) for snoek and yellowtail respectively were within regulatory guidelines. However, 10% (n=2) of snoek exceeded Hg maximum allowable limit, suggesting caution and further investigation. Overall, two meals (150g) per week of snoek or larger yellowtail (12-15kg) can be safe for human (adult) consumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of foliar applied (Zn, Fe, Cu and Mn) in citrus production

International Nuclear Information System (INIS)

Khurshid, F.; Sarwar, S.; Khattak, R.A.

2008-01-01

A study was conducted to evaluate the impact of micronutrients (Zn, Fe, Cu and Mn) on sweet orange (Citrus Sinensis L.), blood red var., on farmer's orchard at Khanpur, district Haripur, NWFP, during 2002-03. Micronutrients were applied in foliar sprays over the canopy of each tree. The main effects and interactions of Zinc sulphate (Zn), iron sulphate (Fe), Copper Sulphate (Cu) and Manganese Sulphate (Mn) were studied in factorial combinations. A basal dose of nitrogen, phosphorus and potassium was applied at the rate 1.5, 1 and 1 kg tree/sup -1/. Zn, Fe, Cu and Mn were applied alone and in various combinations at the rate 0.115, 0.057, 0.05 and 0.13 kg in 100 liters of water. Application of micronutrients significantly increased Zn, Fe, Cu and Mn concentrations in leaves, compared with control. Zn treatments significantly increased the yield, number of fruit and total sugar. Manganese treatments significantly increased the total soluble solids and reduced the acidity of fruit juice. Other quality parameters, including fruit size, percent peel, percent pulp, sugar as well as total soluble solids, were improved with the application of Zn, Fe, Cu and Mn. (author)

Levels of essential and toxic metals in fenugreek seeds (Trigonella Foenum-Graecum L. cultivated in different parts of Ethiopia

Directory of Open Access Journals (Sweden)

Mebrahtu Hagos

Full Text Available Summary The levels of the major (Ca, K, Na, Mg, trace (Fe, Cr, Ni, Zn, Mn, Cu, Co, and toxic (Pb, Cd metals in the seeds of fenugreek cultivated in different regions of Ethiopia were determined by flame atomic absorption spectrophotometry (FAAS. Wet ashing was used to digest 0.5 g of fenugreek seed flour using 1.5 mL of HNO3 and HClO4 acid mixtures (5:1 ratio, 30 min pre-digestion time, 45 min total digestion time and a temperature of 150 °C. Thirteen elements were determined, obtaining concentrations in the following ranges: Ca (15353-36771 mg kg-1 > Fe (6041-18584 mg kg-1 ≈ K (6789-11517 mg kg-1 > Pb (615-2624 mg kg-1 > Na (201-1559 mg kg-1 > Cd (285-464 mg kg-1 > Cr (3-552 mg kg-1 > Ni (31-108 mg kg-1 > Mg (31-102 mg kg-1 > Zn (15-33 mg kg-1 > Mn (16-28 mg kg-1 > Cu (ND-35 mg kg-1 > Co (4-15 mg kg-1. A statistical analysis of variance (ANOVA at the 95% confidence level revealed there were significant differences between the mean metal contents of fourteen sample means, except for Zn. Pearson’s correlation revealed weak positive or negative linear relationships, which implies that the presence of one metal did not affect the presence of the other metals within the plant, except for a few metals. The study showed that fenugreek seeds were a good source of essential metals. However, they also contained large amounts of the toxic metals Cd and Pb and therefore should not be consumed daily.

Optimización de la producción y calidad en cebolla cabezona (Allium cepa mediante el balance nutricional con magnesio y micronutrientes (B, Zn y Mn, Valle Alto del Río Chicamocha, Boyacá

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Gómez Manuel Iván

2007-12-01

Full Text Available

La ausencia de magnesio y micronutrientes (B, Zn y Mn en planes de fertilización limita el balance nutricional en cebolla, debido a que dichos elementos regulan la expresión del potencial productivo del cultivo y la calidad del producto cosechado. La presente investigación fue realizada en un suelo del Distrito de Riego del Alto Chicamocha (DRAC, clasificado taxonómicamente como Sulfic Endoaquept, familia muy fina sobre orgánica, caolinítica, semiactiva, isomésica (fase ácida, moderadamente profunda. Los resultados mostraron respuestas favorables a la fertilización complementaria específica con 70 kg·ha^{- 1} de MgO (micromagnesio granulado 40% MgO, donde se reportaron incrementos de 50 % en el rendimiento de primera, mejora en la gravedad específica con diferencias altamente significativas respecto al solo manejo NPK, y se identificó una mayor eficiencia en la absorción foliar del P estableciéndose una relación positiva Mg/P. Respecto al comportamiento de micronutrientes se presentó una interacción positiva Mn·Zn con 4 kg·ha^-1 Mn (microman-sulfato de manganeso granulado, 20% Mn y 3,5 kg·ha^-1 Zn (microzinc-sulfato de zinc granulado 22% Zn, expresada por incrementos superiores al 18% (P< 0,01 en la producción de cebolla categoría primera. Respecto al manejo NPKMg, las mejoras se observaron directamente en el componente de calidad (diámetro ecuatorial, gravedad específica, características que optimizan la rentabilidad del cultivo; igualmente, se estableció una relación P/Zn importante para el desarrollo, la producción y el manejo nutricional del cultivo. El B no presentó un efecto significativo en las variables evaluadas debido a las altas concentraciones nativas en medios ácidos existentes en este tipo de suelos.

Order parameters and magnetocrystalline anisotropy of off-stoichiometric D0{sub 22} Mn{sub 2.36}Ga epitaxial films grown on MgO (001) and SrTiO{sub 3} (001)

Energy Technology Data Exchange (ETDEWEB)

Lee, Hwachol; Sukegawa, Hiroaki, E-mail: sukegawa.hiroaki@nims.go.jp; Mitani, Seiji; Hono, Kazuhiro [National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)

2015-07-21

We study the relationship between long range order parameters and the magnetocrystalline anisotropy of off-stoichiometric D0{sub 22} Mn{sub 2.36}Ga (MnGa) epitaxial films grown on MgO (001) and SrTiO{sub 3} (STO) (001) single crystalline substrates. MnGa films deposited on MgO (001) show rather large irregular variation in magnetization with increasing substrate temperature in spite of the improved long range order of total atomic sites. The specific site long range order of Mn-I site characterized in the [101] orientation revealed the fluctuation of the occupation fraction of two Mn atomic sites with elevated substrate temperature, which appears more relevant to the observed magnetization change than the long range order of the total atomic sites. In case of MnGa films grown on the lattice-matched STO (001), high long range order of the total atomic sites in spite of the existence of secondary phase represents that the lattice mismatch plays a crucial role in determining the atomic arrangement of Mn and Ga atoms in the off-stoichiometric compositional case of MnGa.

Betel quid chewing as a source of manganese exposure: total daily intake of manganese in a Bangladeshi population.

Science.gov (United States)

Al-Rmalli, Shaban W; Jenkins, Richard O; Haris, Parvez I

2011-02-07

A relationship between betel quid chewing in Bangladeshi populations and the development of skin lesions and tremor has been previously reported, for people exposed to high levels of arsenic (As) through drinking contaminated groundwater. Exposure to manganese (Mn) is also known to induce neurotoxicity and levels of Mn in Bangladeshi groundwater are also high. The present study evaluates betel quid chewing as an overlooked source of Mn exposure in a Bangladeshi population. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine (1) urinary Mn levels for 15 chewers and 22 non-chewers from the ethnic Bangladeshi community in the United Kingdom, and (2) Mn levels in betel quids, its individual components and other Bangladeshi foods. Betel quid chewers displayed a significantly higher (P = 0.009) mean Mn concentration in urine (1.93 μg L(-1)) compared to non-chewers (0.62 μg L(-1)). High levels of Mn were detected in Piper betel leaves with an overall average of 135 mg kg(-1) (range 26 -518 mg kg(-1)). The mean concentration of Mn in betel quid was 41 mg kg(-1) (SD 27) and the daily intake of Mn in the Bangladeshi population was estimated to be 20.3 mg/day. Chewing six betel quids could contribute up to 18% of the maximum recommended daily intake of Mn. We have demonstrated that Mn in betel quids is an overlooked source of exposure to Mn in humans. Chewers display a 3.1 fold increased urinary Mn concentration compared to non-chewers. The practice of betel quid chewing contributes a high proportion of the maximum recommended daily intake of Mn, which could make chewers in Bangladesh more vulnerable to Mn neurotoxicity.

Microstructure and mechanical properties of an extruded Mg-8Bi-1Al-1Zn (wt%) alloy

Energy Technology Data Exchange (ETDEWEB)

Meng, Shuaiju [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Yu, Hui, E-mail: yuhuidavid@gmail.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Materials Commercialization Center, Korea Institute of Materials Science, Changwon 51508 (Korea, Republic of); Zhang, Huixing [Mechanical and Material School, Tianjin Sino-German University of Applied Sciences, Tianjin 300350 (China); Cui, Hongwei [School of Materials Science and Engineering, Shangdong University of Technology, Zibo 255049 (China); Park, Sung Hyuk [School of Materials Science and Engineering, Kyungpook National University, Daegu 702701 (Korea, Republic of); Zhao, Weiming [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); You, Bong Sun [Materials Commercialization Center, Korea Institute of Materials Science, Changwon 51508 (Korea, Republic of)

2017-04-06

In this study, the microstructural evolution and mechanical properties of a newly developed rare earth free Mg-8Bi-1Al-1Zn (BAZ811, in wt%) alloy were investigated and compared with those of a commercial AZ31 alloy. The as-extruded BAZ811 alloy with much finer grain size shows more homogeneous dynamical recrystallized (DRXed) microstructure and weaker basal texture than those of AZ31 alloy. In addition, compared with bimodal structure AZ31 alloy containing only relatively coarse and sparse Al{sub 8}Mn{sub 5} phases, the coexistence of strip-like fragmented Mg{sub 3}Bi{sub 2} precipitate and nano-size Mg{sub 3}Bi{sub 2} particles in the microstructure was observed in BAZ811 alloy. Moreover, the BAZ811 alloy exhibits a tensile yield stress of 291 MPa, an ultimate tensile strength of 331 MPa, an elongation to failure of 14.6% as well as a reduction in yield asymmetry, which is mainly attributed to the combined effects of grain refinement and micro-scale broken Mg{sub 3}Bi{sub 2} particles together with nano-scale spherical Mg{sub 3}Bi{sub 2} precipitates. The strain hardening behavior of both BAZ811 and AZ31 alloys were also discussed in terms of microstructure variation.

MnO_x/C nanocomposite: An insight on high-performance supercapacitor and non-enzymatic hydrogen peroxide detection

International Nuclear Information System (INIS)

Ahuja, Preety; Kumar Ujjain, Sanjeev; Kanojia, Rajni

2017-01-01

Graphical abstract: In-situ inclusion of carbon matrix during growth of MnO_x nanoparticles resulted in MnO_x/C nanocomposite with enhanced electronic diffusion leading to high energy/power densities supercapacitor and highly sensitive H_2O_2 sensor. - Highlights: • MnO_x/C, synthesized via microemulsion method, is electrochemically investigated towards supercapacitor and sensing applications. • In-situ inclusion of conducting carbon in manganese oxide enhances the network conductivity facilitating the charge transfer process. • It provides high energy and power density, 31.6 Wh kg"−"1 and 3.8 kW kg"−"1 respectively, with short relaxation time ∼3 ms for fabricated cell. • MnO_x/C as sensor, exhibits excellent catalytic activity toward H_2O_2 oxidation and offer high sensitivity with low detection limit. - Abstract: In this work, we have used microemulsion method for synthesis of MnO_x/C nanocomposite and investigated its electrochemical properties via fabrication of supercapacitor and non-enzymatic hydrogen peroxide (H_2O_2) sensor. In-situ inclusion of conducting carbon in manganese oxide (MnO_x/C) enhances the network conductivity facilitating the charge transfer process which is beneficial for supercapacitor and sensing applications. MnO_x/C provides high energy and power density, 31.6 Wh kg"−"1 and 3.8 kW kg"−"1 respectively and short relaxation time ∼3 ms for fabricated cell (MnO_x/C//MnO_x/C) endowing excellent power delivery capacity. Furthermore, MnO_x/C as sensor, exhibits excellent catalytic activity toward the oxidation of H_2O_2 and shows high sensitivity (0.37 mA mM"−"1 cm"−"2) with low detection limit (0.5 μM at an S/N of 3). Hence, this study provides new avenue for high performance supercapacitor and H_2O_2 detection.

Seasonal Trends and Inter-Individual Heterogeneity: A multi-species record of Mg, Sr, Ba, & Mn in Planktic Foraminifera from the Modern Cariaco Basin

Science.gov (United States)

Davis, C. V.; Thunell, R.; Astor, Y. M.

2017-12-01

The trace element to calcium ratios (TE/Ca) of planktic foraminifera shells are a valuable tool for paleoceanographic reconstructions, and represent a combination of environmental, ecological and biological signals. We present here a three-year record (2010-2013) of TE/Ca (Mg, Sr, Ba, Mn) from four species of foraminifera (Orbulina universa, Globigerina ruber, Globigerinella siphonifera, and Globorotalia menardii) collected by plankton tow in the modern Cariaco basin. Each tow is paired with in situ measurements of water column properties, allowing a direct comparison between shell geochemistry and calcification environment. A combination of Laser Ablation and solution ICP-MS analyses are used to document seasonality, primarily due to the alternating influence of wind-driven coastal upwelling and riverine inputs, in shell TE/Ca. Individual shell data further allows for the quantification of trace element heterogeneity among individual shells within single tows. All TE/Ca ratios vary temporally and show inter-individual variability within single tows. The spread in TE/Ca differs between element and species, with Mg/Ca ratios being the most variable. Despite this, Mg/Ca still tracks temperature changes in G. ruber, O. universa, and G. menardii, with G. ruber most closely reproducing sea surface temperature. Some species show chamber-to-chamber differences in trace element ratios, with G. ruber Mg/Ca and Ba/Ca decreasing in younger chambers (but not other elements) and Mg/Ca, Mn/Ca and Ba/Ca decreasing in younger chambers in G. siphonifera. We find the original Mn/Ca to be variable both temporally and between species, with G. menardii in some samples having extremely high ratios (100 μmol/mol). Assessing seasonal trends and environmental drivers of TE/Ca variability and quantifying the extent of inter-individual heterogeneity in these species will inform the use of their shells as geochemical proxies.

High-energy MnO2 nanowire/graphene and graphene asymmetric electrochemical capacitors.

Science.gov (United States)

Wu, Zhong-Shuai; Ren, Wencai; Wang, Da-Wei; Li, Feng; Liu, Bilu; Cheng, Hui-Ming

2010-10-26

In order to achieve high energy and power densities, we developed a high-voltage asymmetric electrochemical capacitor (EC) based on graphene as negative electrode and a MnO(2) nanowire/graphene composite (MGC) as positive electrode in a neutral aqueous Na(2)SO(4) solution as electrolyte. MGC was prepared by solution-phase assembly of graphene sheets and α-MnO(2) nanowires. Such aqueous electrolyte-based asymmetric ECs can be cycled reversibly in the high-voltage region of 0-2.0 V and exhibit a superior energy density of 30.4 Wh kg(-1), which is much higher than those of symmetric ECs based on graphene//graphene (2.8 Wh kg(-1)) and MGC//MGC (5.2 Wh kg(-1)). Moreover, they present a high power density (5000 W kg(-1) at 7.0 Wh kg(-1)) and acceptable cycling performance of ∼79% retention after 1000 cycles. These findings open up the possibility of graphene-based composites for applications in safe aqueous electrolyte-based high-voltage asymmetric ECs with high energy and power densities.

Attestation in self-propagating combustion approach of spinel AFe{sub 2}O{sub 4} (A = Co, Mg and Mn) complexes bearing mixed oxidation states: Magnetostructural properties

Energy Technology Data Exchange (ETDEWEB)

Bennet, J., E-mail: b.eenneett@gmail.com [Department of Physics, College of Engineering, Guindy, Anna University, Sardar Patel Road, Chennai,600025 (India); Tholkappiyan, R. [Department of Physics, College of Engineering, Guindy, Anna University, Sardar Patel Road, Chennai,600025 (India); Department of Physics, College of Science, UAE University, Al Ain 15551 (United Arab Emirates); Vishista, K.; Jaya, N. Victor [Department of Physics, College of Engineering, Guindy, Anna University, Sardar Patel Road, Chennai,600025 (India); Hamed, Fathalla [Department of Physics, College of Science, UAE University, Al Ain 15551 (United Arab Emirates)

2016-10-15

Highlights: • Spinel type ferrite compounds AFe{sub 2}O{sub 4} (A = Co, Mg and Mn) have been successfully prepared by self-propagating combustion method using glycine as fuel. • To investigate and confirms the presence of phases in the synthesized ferrite nanoparticles by XRD and FTIR analysis. • The formation of mixed oxidation state of cobalt (Co{sup 2+} and Co{sup 3+}), iron (Fe{sup 2+} and Fe{sup 3+}) and manganese (Mn{sup 2+} and Mn{sup 3+}) ions were studied and confirmed from XPS analysis. • The magnetic properties of the synthesized ferrites were studied by VSM measurement. - Abstract: Spinel type nano-sized ferrite compounds AFe{sub 2}O{sub 4} (A = Co, Mg and Mn) have been successfully prepared by self-propagating combustion method using glycine as fuel at 400 °C under air atmosphere for 4 h. The crystal structure, chemical composition, morphology and magnetic properties of the synthesized samples were characterized by X−ray diffraction, Fourier transform infrared spectroscopy, X−ray photoelectron spectroscopy, Energy dispersive X−ray, Scanning and Transmission electron microscopy and vibrating sample magnetometer. The chemical reaction and role of fuel on the nanoparticles formation were discussed. The XRD pattern of the synthesized samples shows the formation of pure phase with average crystallite size of 97, 57 and 98 nm from Scherrer formula and 86, 54 and 87 nm from Williamson and Hall (W–H) formula respectively. FTIR absorption spectra revealed that the presence of strong absorption peaks near 400–600 cm{sup −1} corresponds to tetrahedral and octahedral complex of spinel ferrites. The relative concentrations of electronic states of elements such as cobalt (Co{sup 2+} and Co{sup 3+}), iron (Fe{sup 2+} and Fe{sup 3+}) and manganese (Mn{sup 2+} and Mn{sup 3+}) oxidation states were studied from XPS and it is found that 55% of Fe ions are in Fe{sup 2+} state and the remaining is in Fe{sup 3+} state and thus the cationic distribution

Heavy Metal Content in Selected Flavouring Plants and in Ultra-Basic Soil of Felda Rokan Barat, Negeri Sembilan, Malaysia

International Nuclear Information System (INIS)

Sahibin Abdul Rahim; Wan Mohd Razi Idris; Zulfahmi Ali Rahman; Tukimat Lihan; Ramlan Omar; Yan, L.K.

2012-01-01

A study was carried out at an ultra basic soil area in Felda Rokan Barat (FRB), Negeri Sembilan. Twenty plants of samples namely chili, turmeric, pandan and lemon grass were collected randomly for the determination of heavy metal contents such as Fe, Cd, Co, Cu, Mn, Ni, Pb, Cr and Zn. Heavy metals in plants were extracted by wet digestion method, whereas available and resistant heavy metals in soil were extracted by sequential extraction. Total heavy metals content in the soil were obtained by summation of resistant and available heavy metals. Heavy metals content in soil and plant extract were determined by using the Flame Atomic Absorption Spectrophotometer (FAAS). Results showed that Fe was the dominant composition in soil in the study area while Cd concentration was very low with values of < 10 mg/ kg. The range of heavy metals concentration in soils were Fe (2618.4 to 4248 mg/ kg), Mn (240.9 to 741.9 mg/ kg), Zn (81.9 to 324.8 mg/ kg), Cr (46.8 to 438.7 mg/ kg), Cu (15.7 to 81.7 mg/ kg), Pb (14.9 to 116.8 mg/ kg), Ni (10.1 to 545.6 mg/ kg), Cd (5.6 to 10.6 mg/ kg) dan Co (0.8 to 126.1 mg/ kg). Available Fe recorded the highest value in all of the plant substrates followed by Mn, Zn, Pb, Ni, Cr, Cu, Co and Cd. Based on percentage of availability Mn, Pb and Zn are considered most available by plant with availability percentage of 8 to 10 %. Concentration of Fe, Mn, Ni and Zn were high in all parts of plants compared to the other metals. The value of biological absorption coefficient (BAC) in chili, turmeric, pandan and lemon grass were in the range of 0.02-0.36, 0.03-0.41, 0.03-0.63 and 0.03-1.15, respectively. It can be concluded that the uptake of heavy metals by plants were normal even though the heavy metals concentration in the ultra basic soil was high. (author)

Heavy metal concentrations in marine molluscs from the Moroccan coastal region

Energy Technology Data Exchange (ETDEWEB)

Maanan, Mohamed [Geolittomer, UMR 6554 LETG - CNRS, Universite de Nantes, BP 81227, 44312 Nantes Cedex 3 (France)], E-mail: mohamed.maanan@univ-nantes.fr

2008-05-15

Mussels (Mytilus galloprovincialis), clams (Venerupis decussatus) and oysters (Crassostrea gigas) were sampled seasonally during 2004-2005, from different coastal environments of Morocco in order to measure their accumulated heavy metal concentrations. The concentrations of Hg and Pb were determined by AFS and ICP-MS methods, respectively, whilst the remaining metals (Cd, Cr, Cu, Mn, Zn and Ni) were quantified by AAS. The soft tissue concentrations of the mussels were on average 7.2 mg kg{sup -1} (Cd), 9.6 mg kg{sup -1} (Pb), 0.6 mg kg{sup -1} (Hg), 26.8 mg kg{sup -1} (Cu), 8.8 mg kg{sup -1} (Cr), 292 mg kg{sup -1} (Zn), 20.8 mg kg{sup -1} (Mn) and 32.8 mg kg{sup -1} (Ni). The highest tissue heavy metal concentrations were recorded in the south from the industrial area of Jorf Lasfar. The relationships between metal concentration and season in each species showed very similar annual profiles with a peak observed around spring-summer. Statistical analysis indicated that different species showed different bioaccumulation of metals depending on study site and season. - The accumulated metal concentrations in bivalves from the clean stations may be considered as useful Atlantic coast reference background levels for future comparison.

Concentrations of tylvalosin and 3-O-acetyltylosin attained in the synovial fluid of swine after administration by oral gavage at 50 and 5 mg/kg.

Science.gov (United States)

Canning, P; Bates, J; Hammen, K; Coetzee, J; Wulf, L; Rajewski, S; Wang, C; Karriker, L

2016-12-01

The objectives of this study were to determine the concentration of tylvalosin (TVN) and its metabolite, 3-O-acetyltylosin (3AT) in the synovial fluid of growing pigs when administered as a single bolus by oral gavage at target doses of 50 mg/kg (Trial 1) and 5 mg/kg (Trial 2). TVN is a water soluble macrolide antimicrobial used in swine production. The stability of the drug in synovial fluid samples stored at -70 °C up to 28 days was also evaluated in Trial 2. In Trial 1, eight pigs were randomly assigned to one of eight time points for euthanasia and synovial fluid collection: 0, 1, 2, 3, 4, 6, 9, 12 h postgavage. For Trial 2, 24 pigs were randomly allocated to one terminal collection time point at 0, 2, 4, 6, 8 or 10 h postgavage. Synovial fluid was analyzed to determine TVN and 3AT concentrations. TVN and 3AT were detected in Trial 1 at all time points, except 0 h. At 2 h postgavage for trial 2, the mean concentrations peaked at 31.17 ng/mL (95% CI: 18.62-52.16) for TVN and at 58.82 ng/mL (95% CI: 35.14-98.46) for 3AT. Storage duration did not impact TVN or 3AT concentrations (P-value 0.9732). © 2016 John Wiley & Sons Ltd.

Mechanism of formation of perovskite phase and dielectric properties of Pb(Zn,Mg)1/3Nb2/3O3 ceramics prepared by columbite precursor routes

International Nuclear Information System (INIS)

Jang, H.M.; Cho, S.R.; Lee, K.M.

1995-01-01

The mechanism of formation of the perovskite phase and the dielectric properties of Pb(Zn,Mg) 1/3 Nb 2/3 O 3 (PZMN) ceramics were examined using two different types of columbite precursors, (Mg,Zn)Nb 2 O 6 (MZN) and MgNb 2 O 6 + ZnNb 2 O 6 (MN + ZN). The formation of perovskite phase in the PbO + MN + ZN system is characterized by an initial rapid formation of Mg-rich perovskite phase, followed by a sluggish formation of Zn-rich perovskite phase. On the other hand, due to the formation of pyrochlore phase of mixed divalent cations Pb 2-x (Zn,Mg) y Nb 2-y O 7-x-3y/2 , the pyrochlore/perovskite transformation in the PbO + MZN system proceeded uniformly with a spatial homogeneity. Further analysis suggested that the formation of perovskite phase is a diffusion-controlled process. The degree of diffuseness of the rhombohedral/cubic phase transition (DPT) is higher in the PbO + MN + ZN system than in the PbO + MZN specimen for T > T max (temperature of the dielectric permittivity maximum), indicating a broadened compositional distribution of the B-site cations in the PbO + MN + ZN system

Random comparison study of the clinical response to 153Sm-EDTMP 1.0 mCi/kg and 1.5 mCi/kg

International Nuclear Information System (INIS)

Pan, Z.; Zhu, S.

2001-01-01

Sixty-seven patient with painful bone metastases were randomized to two groups. Group 1 (n=34) received 1.0 mCi/kg of 153 Sm-EDTMP and group II (n=33) received 1.5 mCi/kg. All of them met inclusion criteria and there was no significantly difference between the basic conditions of two groups. After receiving 153 Sm-EDTMP intravenously, all patients were kept in close follow-up weekly with blood counting, physician visiting and collecting patient's self-filling-in diary including pain score, Karnofsky performance scale and analgesic consumption. The follow-up duration was six weeks. The final overall condition assessed by physician were graded into no change (including worse), slight relief, significant relief and complete relief. Only significant relief and complete relief were considered as effectiveness for pain relief. Haematological toxicity grade was evaluated based on the nadir of WBC ad PLT counts. The results indicated that the higher dosage group had a higher effectiveness rate (75.76%) compared to the lower dosage group (67.65%), but without statistic significance (x 2 =0.5365, 0.25 153 Sm-EDTMP could be used for those patients with better haematological function and 1.0 mCi/kg used for those patients with poorer haematological function. (author)

Rational design of octahedron and nanowire CeO2@MnO2 core-shell heterostructures with outstanding rate capability for asymmetric supercapacitors.

Science.gov (United States)

Zhu, Shi Jin; Jia, Jia Qi; Wang, Tian; Zhao, Dong; Yang, Jian; Dong, Fan; Shang, Zheng Guo; Zhang, Yu Xin

2015-10-14

Two kinds of novel CeO2@MnO2 nanostructures have been synthesized via a self-assembly strategy. The as-prepared CeO2 nanowire@MnO2 nanostructures exhibited unprecedented pseudocapacitance performance (255 F g(-1)) with outstanding rate capability. A new mechanism based on the synergistic effect between CeO2 and MnO2 was proposed to interpret this phenomenon. When assembled as an asymmetric supercapacitor, an energy density of 27.5 W h kg(-1) with a maximum power density of 1.6 kW kg(-1) was achieved for CeO2 nanowire@MnO2 nanostructures.

MnO{sub x}/C nanocomposite: An insight on high-performance supercapacitor and non-enzymatic hydrogen peroxide detection

Energy Technology Data Exchange (ETDEWEB)

Ahuja, Preety, E-mail: drpreetyahuja@gmail.com [Department of Chemistry, Jamia Hamdard, Delhi 110062 (India); Kumar Ujjain, Sanjeev [Department of Physics, Indian Institute of Technology, Kanpur, UP 208016 (India); Kanojia, Rajni [Department of Chemistry, Shivaji College, University of Delhi, Delhi 110027 (India)

2017-05-15

Graphical abstract: In-situ inclusion of carbon matrix during growth of MnO{sub x} nanoparticles resulted in MnO{sub x}/C nanocomposite with enhanced electronic diffusion leading to high energy/power densities supercapacitor and highly sensitive H{sub 2}O{sub 2} sensor. - Highlights: • MnO{sub x}/C, synthesized via microemulsion method, is electrochemically investigated towards supercapacitor and sensing applications. • In-situ inclusion of conducting carbon in manganese oxide enhances the network conductivity facilitating the charge transfer process. • It provides high energy and power density, 31.6 Wh kg{sup −1} and 3.8 kW kg{sup −1} respectively, with short relaxation time ∼3 ms for fabricated cell. • MnO{sub x}/C as sensor, exhibits excellent catalytic activity toward H{sub 2}O{sub 2} oxidation and offer high sensitivity with low detection limit. - Abstract: In this work, we have used microemulsion method for synthesis of MnO{sub x}/C nanocomposite and investigated its electrochemical properties via fabrication of supercapacitor and non-enzymatic hydrogen peroxide (H{sub 2}O{sub 2}) sensor. In-situ inclusion of conducting carbon in manganese oxide (MnO{sub x}/C) enhances the network conductivity facilitating the charge transfer process which is beneficial for supercapacitor and sensing applications. MnO{sub x}/C provides high energy and power density, 31.6 Wh kg{sup −1} and 3.8 kW kg{sup −1} respectively and short relaxation time ∼3 ms for fabricated cell (MnO{sub x}/C//MnO{sub x}/C) endowing excellent power delivery capacity. Furthermore, MnO{sub x}/C as sensor, exhibits excellent catalytic activity toward the oxidation of H{sub 2}O{sub 2} and shows high sensitivity (0.37 mA mM{sup −1} cm{sup −2}) with low detection limit (0.5 μM at an S/N of 3). Hence, this study provides new avenue for high performance supercapacitor and H{sub 2}O{sub 2} detection.

Nanowire Na0.35MnO2 from a hydrothermal method as a cathode material for aqueous asymmetric supercapacitors

Science.gov (United States)

Zhang, B. H.; Liu, Y.; Chang, Z.; Yang, Y. Q.; Wen, Z. B.; Wu, Y. P.; Holze, R.

2014-05-01

Nanowire Na0.35MnO2 was prepared by a simple and low energy consumption hydrothermal method; its electrochemical performance as a cathode material for aqueous asymmetric supercapacitors in Na2SO4 solution was investigated. Due to the nanowire structure its capacitance (157 F g-1) is much higher than that of the rod-like Na0.95MnO2 (92 F g-1) from solid phase reaction although its sodium content is lower. When it is assembled into an asymmetric aqueous supercapacitor using activated carbon as the counter electrode and aqueous 0.5 mol L-1 Na2SO4 electrolyte solution, the nanowire Na0.35MnO2 shows an energy density of 42.6 Wh kg-1 at a power density of 129.8 W kg-1 based on the total weight of the two electrode material, higher than those for the rod-like Na0.95MnO2, with an energy density of 27.3 Wh kg-1 at a power density of 74.8 W kg-1, and that of LiMn2O4. The new material presents excellent cycling behavior even when dissolved oxygen is not removed from the electrolyte solution. The results hold great promise for practical applications of this cathode material since sodium is much cheaper than lithium and its natural resources are rich.

Biomonitoring of heavy metals and arsenic on the east coast of the Middle Adriatic Sea using Mytilus galloprovincialis

International Nuclear Information System (INIS)

Orescanin, Visnja; Lovrencic, Ivanka; Mikelic, Luka; Barisic, Delko; Matasin, Zeljka; Lulic, Stipe; Pezelj, Durdica

2006-01-01

Results of two years monitoring of heavy metals and arsenic concentrations in soft tissue of Mediterranean blue mussel Mytilus galloprovincialis are presented. Samples were taken at six localities (five exposed to various pollution sources and one control site) on the east coast of the Middle Adriatic in October 2003 and 2004 and in April 2004 and 2005. All measurements were carried out with source excited Energy Dispersive X-ray Fluorescence Method (EDXRF). Measured concentrations were in the following ranges: Pb (2-7 mg/kg); As (4-30 mg/kg); Cr (1-2.9 mg/kg); Mn (2-13 mg/kg); Fe (53.4-719 mg/kg); Ni (0.8-5 mg/kg); Cu (3.7-11.1 mg/kg) and Zn (59.1-273 mg/kg). Maximum values of the most elements were measured in samples from the most polluted Vranjic region. Statistically significant difference among six localities (p = 0.05) was found for As, Fe and Zn while Mn, Fe and Cu showed significantly higher concentrations in spring period. None of the selected elements showed significant difference between the control and exposed regions

Preliminary study of the characteristics of a high Mg containing Al-Mg-Si alloy

International Nuclear Information System (INIS)

Yan, F; McKay, B J; Fan, Z; Chen, M F

2012-01-01

An Al-20Mg-4Si high Mg containing alloy has been produced and its characteristics investigated. The as-cast alloy revealed primary Mg 2 Si particles evenly distributed throughout an α-Al matrix with a β-Al 3 Mg 2 fully divorced eutectic phase observed in interdendritic regions. The Mg 2 Si particles displayed octahedral, truncated octahedral, and hopper morphologies. Additions of Sb, Ti and Zr had a refining influence reducing the size of the Mg 2 Si from 52 ± 4 μm to 25 ± 0.1 μm, 35 ± 1 μm and 34 ± 1 μm respectively. HPDC tensile test samples could be produced with a 0.6 wt.% Mn addition which prevented die soldering. Solution heating for 1 hr was found to dissolve the majority of the Al 3 Mg 2 eutectic phase with no evidence of any effect on the primary Mg 2 Si. Preliminary results indicate that the heat treatment has a beneficial effect on the elongation and the UTS.

Concentration and accumulation of nutrients in the aerial biomass of teak plantations 3 to 18 old, in the Panama Canal watershed.

Directory of Open Access Journals (Sweden)

Rafael Murillo

2015-11-01

Full Text Available Tissue samples from aerial biomass compartments (bark, wood, primary and secondary branches, and foliage were taken from 16 dominant trees of teak in plantations of the Panama Canal watershed, whose volume yield ranged between 9.4 and 13.3 m3 ha-1. year-1 at ages 3 and 18 years, respectively, growing in clayey, red, and acid Ultisols. Wet and dry weight of the different tissues was measured and subsamples taken to be analyzed for macronutrients (N, K, Ca, Mg, P and S and micronutrients (Fe, Mn, Zn, Cu and B. Regression analyses allowed to relate nutrients accumulation with tree age. Dry biomass of the wood was 59.6% (C.V. 5% of total dry biomass, while primary branches, bark, foliage, and secondary branches represented 16.6, 9.4, 7.9, and 6.5, respectively. Larger concentrations of macronutrients were Ca (2.01% found in the bark, and N in the foliage (1.98%. As for micronutrients, larger concentrations were found in the bark, in the order of Fe (767 mg.kg-1, Mn (60 mg.kg-1 and Zn (50 mg.kg-1. At 18 years of age accumulation of macronutrients was 15.9 kg. tree-1 (7.3 kg Ca, 3.9 kg N, 2.6 kg K, 1.0 kg Mg, 0.7 kg P and 0.4 kg S and 124 g of micronutrients (89 g Fe, 18 g Zn, 9 g B, 5 g Mn and 3 g Cu.

Distribution of potentially toxic elements (PTEs) in tailings, soils, and plants around Gol-E-Gohar iron mine, a case study in Iran.

Science.gov (United States)

Soltani, Naghmeh; Keshavarzi, Behnam; Moore, Farid; Sorooshian, Armin; Ahmadi, Mohamad Reza

2017-08-01

This study investigated the concentration of potentially toxic elements (PTEs) including Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, V, and Zn in 102 soils (in the Near and Far areas of the mine), 7 tailings, and 60 plant samples (shoots and roots of Artemisia sieberi and Zygophylum species) collected at the Gol-E-Gohar iron ore mine in Iran. The elemental concentrations in tailings and soil samples (in Near and Far areas) varied between 7.4 and 35.8 mg kg -1 for As (with a mean of 25.39 mg kg -1 for tailings), 7.9 and 261.5 mg kg -1 (mean 189.83 mg kg -1 for tailings) for Co, 17.7 and 885.03 mg kg -1 (mean 472.77 mg kg -1 for tailings) for Cu, 12,500 and 400,000 mg kg -1 (mean 120,642.86 mg kg -1 for tailings) for Fe, and 28.1 and 278.1 mg kg -1 (mean 150.29 mg kg -1 for tailings) for Ni. A number of physicochemical parameters and pollution index for soils were determined around the mine. Sequential extractions of tailings and soil samples indicated that Fe, Cr, and Co were the least mobile and that Mn, Zn, Cu, and As were potentially available for plants uptake. Similar to soil, the concentration of Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, and Zn in plant samples decreased with the distance from the mining/processing areas. Data on plants showed that metal concentrations in shoots usually exceeded those in roots and varied significantly between the two investigated species (Artemisia sieberi > Zygophylum). All the reported results suggest that the soil and plants near the iron ore mine are contaminated with PTEs and that they can be potentially dispersed in the environment via aerosol transport and deposition.

Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in Atriplex halimus and Rosmarinus officinalis.

Science.gov (United States)

Tapia, Y; Eymar, E; Gárate, A; Masaguer, A

2013-05-01

To assess metal mobility in pruning waste and biosolids compost (pH 6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g L(-1), pH 2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7 ± 0.1-3.3 ± 0.1 mg kg(-1)), Fe (49.2 ± 5.2-76.8 ± 6.8 mg kg(-1)), and Mn (7.2 ± 1.1-11.4 ± 0.7 mg kg(-1)) in leaves of R. officinalis, whereas the concentration of only Mn (25.4 ± 0.3-42.2 ± 2.9 mg kg(-1)) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.

Effect of Fe substitution on magnetocaloric effect in La0.7Sr0.3Mn1-xFexO3 (0.05≤x≤0.20)

International Nuclear Information System (INIS)

Barik, S.K.; Krishnamoorthi, C.; Mahendiran, R.

2011-01-01

We have studied the effect of Fe substitution on magnetic and magnetocaloric properties in La 0.7 Sr 0.3 Mn 1-x Fe x O 3 (x=0.05, 0.07, 0.10, 0.15, and 0.20) over a wide temperature range (T=10-400 K). It is shown that substitution by Fe gradually decreases the ferromagnetic Curie temperature (T C ) and saturation magnetization up to x=0.15 but a dramatic change occurs for x=0.2. The x=0.2 sample can be considered as a phase separated compound in which both short-range ordered ferromagnetic and antiferromagnetic phases coexist. The magnetic entropy change (-ΔS m ) was estimated from isothermal magnetization curves and it decreases with increase of Fe content from 4.4 J kg -1 K -1 at 343 K (x=0.05) to 1.3 J kg -1 K -1 at 105 K (x=0.2), under ΔH=5 T. The La 0.7 Sr 0.3 Mn 0.93 Fe 0.07 O 3 sample shows negligible hysteresis loss, operating temperature range over 60 K around room temperature with refrigerant capacity of 225 J kg -1 , and magnetic entropy of 4 J kg -1 K -1 which will be an interesting compound for application in room temperature refrigeration. - Research highlights: → We report magnetocaloric effect in La 0.7 Sr 0.3 Mn 1-x Fe x O 3 (x=0-0.2). → Magnetic entropy change (ΔS m ) decreases with increasing x. → A large ΔS m and refrigeration capacity are found around 300 K in x=0.07.

Studies of diluted antiferromagnets MnxMg1-xTiO3 with x=0.55 and 0.70 by muon spin relaxation method

International Nuclear Information System (INIS)

Fukaya, A.; Ito, A.; Torikai, E.; Nishiyama, K.; Nagamine, K.

1997-01-01

Longitudinal fields μSR measurements have been performed in order to probe the spin dynamics in the diluted antiferromagnets Mn x Mg 1-x TiO 3 with x=0.70 and 0.55. In the x=0.70 sample which forms the antiferromagnetic long-range order, the static and fluctuating fields coexist at the muon stopping site below T N . On the other hand, in the x=0.55 sample which shows the spin-glass behavior, the local fields fluctuate rather fast even below T SG . We infer that this drastic change occurs when Mn x Mg 1-x TiO 3 transforms from an antiferromagnetic system to a spin-glass system by dilution

Differences of the essential mineral element levels in the milk of Croatian Coldblood horse and Littoral-Dinaric donkey

Directory of Open Access Journals (Sweden)

Nina Bilandžić

2014-03-01

Full Text Available The concentrations of essential elements in the milk of Croatian Coldblood mares and Littoral- Dinaric donkey were measured. The mean element contents in horse milk were (mg/kg: Ca 687.1, Mg 72.1, K 637.7, Na 143.5, Cu 0.126, Fe 0.235, Se 0.01, Zn 2.06, Mn<0.01. In donkey milk, the mean element contents were (mg/kg: Ca 815.4, Mg 80.8, K 887.7, Na 217.6, Cu 0.027, Fe 0.196, Zn 2.36, Mn 0.016. In horse milk, moderate correlations were found between the elements: Ca-K, Mg-Se, Mg-K, Mg-Cu, Se-Cu, Se-Fe, Mn-K. Strong correlations were found among elements in donkey milk: Ca-Na, Ca-K, Ca-Cu, K-Na, K-Cu, Cu-Mn. Significant differences between Na, K and Cu concentrations were obtained between the two species. Other elements concentrations were similar in both species.

40 KG Sample of Fish-Clay from Stevns Klint, Denmark

Science.gov (United States)

Gwozdz, R.; Hansen, H. J.; Rasmussen, K. L.

1992-07-01

In March 1986 a 50-m-long exposure of the cliff at Stevns Klint fell down and exposed about 40 square meters of Fish Clay. Due to this extraordinary event we were able to pick by hand about 50 kg black KT boundary layer material. After drying, the material was homogenized using a wooden pestle and an agate mortar. The powdered material was sieved through 200 mesh nylon gauze. The fraction larger than 200 mesh was collected and powdered again in an agate mortar. After four repetitions the amount of material with grain size less than 200 mesh was about 40 kg. The fraction larger than 200 mesh was reduced to about 7 kg. The 40-kg powder was mixed in a rotating polyethylene drum for three weeks. The material was analyzed by instrumental neutron activation analysis, atomic absorption and X-ray fluorescence analysis for about 40 elements. INAA was made on 20 aliquots with weight about 300 mg, 20 aliquots with weight about 80 mg, and 30 with weights between 10 and 20 mg. The preliminary results show that our KT boundary sample (1) is very homogeneous, (2) is very close in composition to other K-T boundary clays analyzed by us or described in the literature, and (3) has an Ir concentration of 32 +- 2 ng/g. We hope that our Fish Clay sample (termed by us "Mesozoic Midnight") after analysis in other laboratories and by other analytical methods may qualify as reference material in analytical work on boundary clay material.

Protective effect of kombucha mushroom (KM) tea on phenol-induced cytotoxicity in albino mice.

Science.gov (United States)

Yapar, Kursad; Cavusoglu, Kultigin; Oruc, Ertan; Yalcin, Emine

2010-09-01

The present study was carried out to evaluate the protective role of kombucha mushroom (KM) tea on cytotoxicity induced by phenol (PHE) in mice. We used weight gain and micronucleus (MN) frequency as indicators of cytotoxicity and supported these parameters with pathological findings. The animals were randomly divided into seven groups: (Group I) only tap water (Group II) 1000 microl kg(-1) b. wt KM-tea, (Group III) 35 mg kg(-1) body wt. PHE (Group IV) 35 mg kg(-1) body wt. PHE + 250 microl kg(-1) b. wt KM-tea (Group V) 35 mg kg(-1) b. wt PHE + 500 microl kg(-1) b. wt KM-tea (Group VI) 35 mg kg(-1) b. wt PHE + 750 microl kg(-1) b. wt KM-tea, (Group VII) 35 mg kg(-1) b. wt PHE + 1000 microl kg(-1) b. wt KM-tea, for 20 consecutive days by oral gavage. The results indicated that all KM-tea supplemented mice showed a lower MN frequency than erythrocytes in only PHE-treated group. There was an observable regression on account of lesions in tissues of mice supplemented with different doses of KM-tea in histopathological observations. In conclusion, the KM-tea supplementation decreases cytotoxicity induced by PHE and its protective role is dose-dependent.

Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

Science.gov (United States)

Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

2016-08-01

Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

Magnetic and magnetocaloric properties of La{sub 1.4-x}Yb{sub x}Ca{sub 1.6}Mn{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Himcinschi, C. [Babes-Bolyai Univ., Cluj-Napoca (Romania). Faculty of Physics; GSI, Strasbourg (France). Inst. de Physique et Chemie des Materiaux; Burzo, E. [Babes-Bolyai Univ., Cluj-Napoca (Romania). Faculty of Physics; Deville, J.P. [GSI, Strasbourg (France). Inst. de Physique et Chemie des Materiaux

2001-07-01

Magnetic and magnetocaloric properties of La{sub 1.4-x}Yb{sub x}Ca{sub 1.6}Mn{sub 2}O{sub 7} system were studied. Polycrystalline samples with x = 0 and 0.2 were prepared by solid state reaction. Magnetic measurements show that Curie temperatures decrease from 246 K for x = 0 down to 211 K for x = 0.2. The temperature dependences of the magnetic entropy change {delta}S{sub M}, show peaks close to the magnetic transition temperatures. Peak values of {delta}S{sub M} = 2.7 J/kg K and 2.1 J/kg K were obtained for compositions x = 0 and 0.2. The decrease in {delta}S{sub M} when changing composition was correlated with the diminution of exchange interactions. (orig.)

Giant anisotropy of magnetocaloric effect in TbMnO3 single crystals

Science.gov (United States)

Jin, Jin-Ling; Zhang, Xiang-Qun; Li, Guo-Ke; Cheng, Zhao-Hua; Zheng, Lin; Lu, Yi

2011-05-01

The magnetocaloric effect (MCE) in TbMnO3 single crystals was investigated by isothermal magnetization curves for the ab plane at low temperatures. Large magnetic entropy change, ΔSM = -18.0 J/kg K, and the refrigerant capacity, RC = 390.7 J/kg, are achieved near the ordering temperature of Tb3+ moment (TNTb) under 70 kOe along the a axis. Furthermore, the TbMnO3 single crystal exhibits a giant MCE anisotropy. The difference of ΔSMand RC between the a and b axes is field and temperature dependent, which reaches maximum values of 11.4 J/kg K and 304.1 J/kg, respectively. By taking magnetocrystalline anisotropy into account, the rotating ΔSMwithin the ab plane can be well simulated, indicating that the anisotropy of ΔSMis directly contributed from the magnetocrystalline anisotropy. Our finding for giant MCE anisotropy in TbMnO3 single crystals explores the possibility of using this material for magnetic refrigerators by rotating its magnetization vector rather than moving it in and out of the magnet.

Consumption of arsenic and other elements from vegetables and drinking water from an arsenic-contaminated area of Bangladesh.

Science.gov (United States)

Rahman, Mohammad Mahmudur; Asaduzzaman, Md; Naidu, Ravi

2013-11-15

The study assesses the daily consumption by adults of arsenic (As) and other elements in drinking water and home-grown vegetables in a severely As-contaminated area of Bangladesh. Most of the examined elements in drinking water were below the World Health Organization (WHO) guideline values except As. The median concentrations of As, cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), Mn, nickel (Ni), and zinc (Zn) in vegetables were 90 μg kg(-1), 111 μg kg(-1), 0.80 mg kg(-1), 168 μg kg(-1), 13 mg kg(-1), 2.1 mg kg(-1), 65 mg kg(-1), 1.7 mg kg(-1), and 50 mg kg(-1), respectively. Daily intakes of As, Cd, Cr, Co, Cu, Pb, manganese (Mn), Ni, and Zn from vegetables and drinking water for adults were 839 μg, 2.9 μg, 20.8 μg, 5.5 μg, 0.35 mg, 56.4 μg, 2.0mg, 49.1 μg, and 1.3mg, respectively. The health risks from consuming vegetables were estimated by comparing these figures with the WHO/FAO provisional tolerable weekly or daily intake (PTWI or PTDI). Vegetables alone contribute 0.05 μg of As and 0.008 mg of Cu per kg of body weight (bw) daily; 0.42 μg of Cd, 8.77 mg of Pb, and 0.03 mg of Zn per kg bw weekly. Other food sources and particularly dietary staple rice need to be evaluated to determine the exact health risks from such foods. Copyright © 2012 Elsevier B.V. All rights reserved.

Trace/Heavy Metal Impact on Agricultural Soils from Commonly used Fertilizers of Bangladesh

International Nuclear Information System (INIS)

Islam, A.; Jolly, Y. N.

2005-01-01

On investigation of seven commonly used fertilizers of Bangladesh for evaluation of their trace/heavy metal impact on the agricultural soils it was observed that TSP, SSP and Cow-dung were more potential in supplying a broad range of these elements including toxin ones such as, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr, Y, Pb, Cd. In phosphate fertilizers, the concentrations of Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb ranged from 106-129, 21.1-124, 12.2-16.1, 8.6-27.1, 8.2-12.5, 93.5-245, 8.4-12.1 mgkg -1 respectively. In cow-dung the respective contents of the same elements except Cd were 8.1, 820, 11.1, 6.1, 12.4, 72.2, 12.1 mg kg -1 . Zinc sulphate was also found to be a potential fertilizer capable of supplying Mn, Co, Ni, Cu, Zn, Cd, Pb, containing 182, 311, 63, 10.5, 300, 27.5, 28.1 mg kg -1 respectively. MP and Gypsum has shown to be of less potential in adding trace/heavy elements in soils. MP contained Mn, Fe, Br, Sr and its Mn concentration was 13.2 mg kg -1 . The elements, Fe, Cu, Zn, Sr were measured in Gypsum where Cu and Fe concentrations were 15.3 and 13.2 mg kg -1 respectively. Urea was found to contain Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br and Sr at low levels in comparison with other fertilizers. The trace/heavy metals load from chemical fertilizers per hectare of agricultural land per year was also calculated. The Maximum input of V, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb were 14.8, 23.2, 22.3, 646, 2.9, 4.9, 3.9, 2816, 2.2 and 4.5 g respectively.(author)

Evaluation of the magnetocaloric response of nano-sized La0.7Ca0.3Mn1-xNixO3 manganites synthesized by auto-combustion method

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Gómez, Adrián; Chavarriaga, Edgar; Supelano, Iván; Parra, Carlos Arturo; Morán, Oswaldo

2018-05-01

A systematic study of the dependence of the magnetization on the magnetic field around the ferromagnetic-paramagnetic phase transition temperature is carried out on La0.7Ca0.3Mn1-xNixO3 (x=0, 0.02, 0.07, and 1) samples synthesized by auto-combustion method. The successful substitution of Mn3+ ions by Ni2+ ions in the La0.7Ca0.3MnO3 lattice is corroborated by X-ray diffraction technique. Banerjees criteria, Arrott plots, and the scaling hypothesis are used to analyze the experimental data. It is verified that the Ni-doping increases the operating temperature range for magnetocaloric effect through tuning of the magnetic transition temperature. Probably, the replacement of Mn3+ by Ni2+ ions in the La0.7Ca0.3MnO3 lattice weakens the Mn3+-O-Mn4+ double exchange interaction, which leads to a decrease in the transition temperature and magnetic moment in the samples. The Arrott plots suggest that the phase transition from ferromagnetic to paramagnetic in the nano-sized manganite is of second order. The analysis of the magnetization results show that the maximum magnetic entropy changes observed for x=0, 0.02, 0.07, and 0.1 compositions are 0.85, 0.77, 0.63, and 0.59 J/kg K, under a magnetic field of 1.5 T. These values indicate that the magnetic entropy change achieved for La0.7Ca0.3Mn1-xNixO3 manganites synthesized by auto-combustion method is higher than those reported for other manganites with comparable Ni-doping levels but synthesized by standard solid state reaction. It is also observed that the addition of Ni2+ increases the value of the relative cooling power as compared to that of the parent compound. The highest value of this parameter (˜60 J/kg) is found for a Ni-doping level of 2 % around 230 K in a field of 1.5 T.

Non radiative decay of Mn2+ emission in LnMB5O10:Bi,Mn (M = Mg,Cd,Zn)

International Nuclear Information System (INIS)

Jagannathan, R.; Rao, R.P.; Kutty, T.R.N.

1990-01-01

The family of lanthanide magnesium pentaborates with Tb(3+) and Eu(3+) as activators are efficient phosphor materials, Mn(2+) emission in these hosts in a subject of intensive investigation owing to its inexpensiveness. The energy transfer process from various sensitizers such as Bi(3+), Ce(3+), and Sb(3+) to Mn(2+) in these hosts have been studied in detail. The non radiative decay of Mn 2+ emission in these hosts is detailed in this paper

Comparative study on nanostructured MnO2/carbon composites synthesized by spontaneous reduction for supercapacitor application

KAUST Repository

Lin, Yen-Po

2011-10-01

MnO2 has been deposited onto two types of carbon (C) substrates, including a non-porous multi-wall carbon nano-tube (CNT) and a porous carbon black (CB) powder, by a solution reduction process where MnO4 - was reduced at 80 °C by the C substrate so as to give nano-crystalline MnO2 directly at the C surface. The nature of the C substrate has profound effects on polymorphicity, microstructure and electrochemical properties, in terms of supercapacitor application, of the resulting oxide. Deposition on CNT produces meso/macro-porous layer containing predominantly spinel MnO2 strongly bonded to the CNTs and having a larger surface area, while that on CB results in birnessite granules with a lower surface area. In addition to having a higher specific capacitance (309 F g-1), the MnO2/CNT electrode exhibits superior power performance (221 F g-1 at 500 mV s-1 or ca. 20 Wh kg -1at 88 kW kg-1) to MnO2/CB due to reduced electronic and ion-diffusion resistances. Furthermore, the MnO2/CNT electrode also exhibits slower self-discharging rate and greater cycling stability. The results indicate that the MnO2 spinel/CNT holds promise for supercapacitor applications. © 2011 Elsevier B.V. All rights reserved.

3D MnO2-graphene composites with large areal capacitance for high-performance asymmetric supercapacitors

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Zhai, Teng; Wang, Fuxin; Yu, Minghao; Xie, Shilei; Liang, Chaolun; Li, Cheng; Xiao, Fangming; Tang, Renheng; Wu, Qixiu; Lu, Xihong; Tong, Yexiang

2013-07-01

In this paper, we reported an effective and simple strategy to prepare large areal mass loading of MnO2 on porous graphene gel/Ni foam (denoted as MnO2/G-gel/NF) for supercapacitors (SCs). The MnO2/G-gel/NF (MnO2 mass: 13.6 mg cm-2) delivered a large areal capacitance of 3.18 F cm-2 (234.2 F g-1) and good rate capability. The prominent electrochemical properties of MnO2/G-gel/NF are attributed to the enhanced conductivities and improved accessible area for ions in electrolytes. Moreover, an asymmetric supercapacitor (ASC) based on MnO2/G-gel/NF (MnO2 mass: 6.1 mg cm-2) as the positive electrode and G-gel/NF as the negative electrode achieved a remarkable energy density of 0.72 mW h cm-3. Additionally, the fabricated ASC device also exhibited excellent cycling stability, with less than 1.5% decay after 10 000 cycles. The ability to effectively develop SC electrodes with high mass loading should open up new opportunities for SCs with high areal capacitance and high energy density.In this paper, we reported an effective and simple strategy to prepare large areal mass loading of MnO2 on porous graphene gel/Ni foam (denoted as MnO2/G-gel/NF) for supercapacitors (SCs). The MnO2/G-gel/NF (MnO2 mass: 13.6 mg cm-2) delivered a large areal capacitance of 3.18 F cm-2 (234.2 F g-1) and good rate capability. The prominent electrochemical properties of MnO2/G-gel/NF are attributed to the enhanced conductivities and improved accessible area for ions in electrolytes. Moreover, an asymmetric supercapacitor (ASC) based on MnO2/G-gel/NF (MnO2 mass: 6.1 mg cm-2) as the positive electrode and G-gel/NF as the negative electrode achieved a remarkable energy density of 0.72 mW h cm-3. Additionally, the fabricated ASC device also exhibited excellent cycling stability, with less than 1.5% decay after 10 000 cycles. The ability to effectively develop SC electrodes with high mass loading should open up new opportunities for SCs with high areal capacitance and high energy density. Electronic

Comparison of 1 mg and 2 mg overnight dexamethasone suppression tests for the screening of Cushing's syndrome in obese patients.

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Sahin, Mustafa; Kebapcilar, Levent; Taslipinar, Abdullah; Azal, Omer; Ozgurtas, Taner; Corakci, Ahmet; Akgul, Emin Ozgur; Taslipinar, Mine Yavuz; Yazici, Mahmut; Kutlu, Mustafa

2009-01-01

Obesity is currently a major public health problem and one of the potential underlying causes of obesity in a minority of patients is Cushing's syndrome (CS). Traditionally, the gold standard screening test for CS is 1 mg dexamethasone overnight suppression test. However, it is known that obese subjects have high false positive results with this test. We have therefore compared the 1 mg and 2 mg overnight dexamethasone suppression tests in obese subjects. Patients whose serum cortisol after ODST was >50 nM underwent and a low-dose dexamethasone suppression test (LDDST); 24-hour urine cortisol was collected for basal urinary free cortisol (UFC). For positive results after overnight 1-mg dexamethasone suppression test we also performed the overnight 2-mg dexamethasone suppression test. We prospectively evaluated 100 patients (22 men and 78 women, ranging in age from 17 to 73 years with a body mass index (BMI) >30 kg/m2 who had been referred to our hospital-affiliated endocrine clinic because of simple obesity. Suppression of serum cortisol to suppression. Thyroid function tests, lipid profiles, homocysteine, antithyroglobulin, anti-thyroid peroxidase antibody levels, vitamin B12, folate levels, insulin resistance [by homeostasis model assessment (HOMA)] and 1.0 mg postdexamethasone (postdex) suppression cortisol levels were measured. We found an 8% false-positive rate in 1 mg overnight test and 2% in 2 mg overnight test (p=0.001). There was no correlation between the cortisol levels after ODST and other parameters. Our results indicate that the 2 mg overnight dexamethasone suppression test (ODST) is more convenient and accurate than 1-mg ODST as a screening test for excluding CS in subjects with simple obesity.

Effect of Preparation Method on Phase Formation Process and Structural and Magnetic Properties of Mn2.5Ge Samples

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R. Sobhani

2016-12-01

Full Text Available In this paper, the phase formation process of Mn2.5Ge samples, prepared by mechanical alloying of Mn and Ge metal powders and annealing, has been studied. Results showed that in the milled samples the stable phase is Mn11Ge8 compound with orthorhombic structure and Pnam space group. The value of saturation magnetization increases by increasing milling time from 0.2 up to 1.95 (Am2Kg-1. The remanece of the samples increases by increasing the milling time while the coercivity decreases. Annealing of 15-hour milled sample results in disappearance of Mn and Ge and the formation of new phases of Mn3Ge, Mn5Ge2, Mn5Ge3 and Mn2.3Ge. Mn3Ge is the main phase with Do22 tetragonal structure and I4/mmm space group which is stable and dominant. The enhancement of saturation magnetization in the annealed sample is related to the formation of three new magnetic phases and the increase of coercivity is due to the presence of Mn3Ge compound with tetragonal structure. Studies were replicated on samples made by arc melting method to compare the results and to investigate the effect of the preparation method on phase formation and structural and magnetic properties of the materials. In these samples the saturation value was in range of 0.2 up to 1.95 (Am2Kg-1 depending on preparation methods. Rietveld refinement shows that Mn2.3Ge sample prepared from arc melted under 620oC anealing is single phase. Magnetic analysis of this sample show a saturation magnetization of 5.252(Am2Kg-1 and 0.005 T coercive field.

Influence of phase composition on microstructure and properties of Mg-5Al-0.4Mn-xRE (x = 0, 3 and 5 wt.%) alloys

International Nuclear Information System (INIS)

Braszczyńska-Malik, K.N.; Grzybowska, A.

2016-01-01

The microstructure and mechanical properties investigations of two AME503 and AME505 experimental alloys in as-cast conditions were presented. The investigated materials were fabricated on the basis of the AM50 commercial magnesium alloy with 3 and 5 wt.% cerium rich mischmetal. In the as-cast condition, both experimental alloys were mainly composed of α-Mg, Al_1_1RE_3 and Al_1_0RE_2Mn_7 intermetallic phases. Additionally, due to non-equilibrium solidification conditions, a small amount of α + γ divorced eutectic and Al_2RE intermetallic phase were revealed. The obtained results also show a significant influence of rare earth elements on Brinell hardness, tensile and compression properties at ambient temperature and especially on creep properties at 473 K. Improved alloy properties with a rise in rare earth elements mass fraction results from an increase in Al_1_1RE_3 phase volume fraction and suppression of α + γ eutectic volume fraction in the alloy microstructure. Additionally, the influence of rare earth elements on the dendrite arm space value was discussed. The presented results also proved the thermal stability of the intermetallic phases during creep testing. - Highlights: • Two different Mg-5Al-0.4Mn alloys containing 3 and 5 wt.% of rare earth elements were fabricated. • Addition of rare earth elements leads to a reduction of dendrite arm spaces. • Mechanical properties depend on the phase composition of the alloys. • The increase of the rare earth elements content causes rise of the creep resistance.

Asymmetric carbon nanotube-MnO2 two-ply yarn supercapacitors for wearable electronics

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Su, Fenghua; Miao, Menghe

2014-04-01

Strong and flexible two-ply carbon nanotube yarn supercapacitors are electrical double layer capacitors that possess relatively low energy storage capacity. Pseudocapacitance metal oxides such as MnO2 are well known for their high electrochemical performance and can be coated on carbon nanotube yarns to significantly improve the performance of two-ply carbon nanotube yarn supercapacitors. We produced a high performance asymmetric two-ply yarn supercapacitor from as-spun CNT yarn and CNT@MnO2 composite yarn in aqueous electrolyte. The as-spun CNT yarn serves as negative electrode and the CNT@MnO2 composite yarn as positive electrode. This asymmetric architecture allows the operating potential window to be extended from 1.0 to 2.0 V and results in much higher energy and power densities than the reference symmetric two-ply yarn supercapacitors, reaching 42.0 Wh kg-1 at a lower power density of 483.7 W kg-1, and 28.02 Wh kg-1 at a higher power density of 19 250 W kg-1. The asymmetric supercapacitor can sustain cyclic charge-discharge and repeated folding/unfolding actions without suffering significant deterioration of specific capacitance. The combination of high strength, flexibility and electrochemical performance makes the asymmetric two-ply yarn supercapacitor a suitable power source for flexible electronic devices for applications that require high durability and wearer comfort.

Effect of soil type and forage crops on manganese content in roughage

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Jakšić Snežana

2017-01-01

Full Text Available The aim of this study was to examine the effects of soil type and forage crops on the content of manganese (Mn in roughages, and forage quality regarding Mn content. The trial was carried out on chernozem and humogley under alfalfa and red clover. Samples for determination of Mn content in plant and total Mn content in soil were digested using the apparatus Milestone Ethos 1 and for Mn determination on ICP-OES Vista Pro-Axial Varian. Average total Mn content in soil of the tested sites was 473.1 mg/kg. Total Mn content in chernozem was higher than in humogley. Average Mn content in forage crops was 28.7 mg/kg. Dry matter Mn content was lower in crops grown on humogley. Mn content was significantly higher in red clover. Significant positive correlation was found between total Mn content in soil and Mn content in crops. Mn concentration in crops was below critical and toxic value.

Comparison of Efficacy and Safety of Liraglutide 3.0 mg in Individuals with BMI above and below 35 kg/m²: A Post-hoc Analysis

Science.gov (United States)

le Roux, Carel; Aroda, Vanita; Hemmingsson, Joanna; Cancino, Ana Paula; Christensen, Rune; Pi-Sunyer, Xavier

2018-01-01

Objective To investigate whether the efficacy and safety of liraglutide 3.0 mg differed between two subgroups, BMI 27 to 3.0 mg were evaluated by testing the interaction between treatment group and baseline BMI subgroup. Results Significantly greater weight loss (0–56 weeks) was observed with liraglutide 3.0 mg versus placebo in all patient groups while on treatment. There was no evidence that the weight-lowering effect of liraglutide 3.0 mg differed between BMI subgroups (interaction p > 0.05). Similarly, for most secondary endpoints significantly greater improvements were observed with liraglutide 3.0 mg versus placebo, with no indication treatment effects differing between subgroups. The safety profile of liraglutide 3.0 mg was broadly similar across BMI subgroups. Conclusion This post-hoc analysis did not indicate any differences in the treatment effects, or safety profile, of liraglutide 3.0 mg for individuals with BMI 27 to 3.0 mg can therefore be considered for individuals with a BMI of ≥35 as well as for those with a BMI of 27 to <35 kg/m². PMID:29145215

Distribution of manganese and selenium in four different pork cuts commercially available in the Serbian market

Science.gov (United States)

Đinović-Stojanović, J.; Nikolić, D.; Janković, S.; Vranić, D.; Milijašević, M.; Babić-Milijašević, J.

2017-09-01

This study aimed to provide information on levels of Mn and Se in four different pork cuts (loin, neck, hind leg and shoulder) commercially available on the Serbian market, with a view to providing information on dietary intakes of metals associated with the consumption of these meat cuts. In total, for 50 pork cuts, the levels of Mn and Se were determined by inductively-coupled plasma mass spectrometry (ICP-MS). The following ranges of Mn and Se were found (mg kg-1) in loin 0.055-0.130 and 0.074-0.365, in neck 0.014-0.365 and 0.045-0.196, in hind leg 0.032-0.099 and 0.066-0.123, in shoulder 0.012-0.290 and 0.027-0.515, respectively. The highest mean levels were obtained for Mn (0.124 mg kg-1) in shoulder and for Se (0.209 mg kg-1) in loin. The Estimated Daily Intake (EDI) of essential elements through consumption of 114.1 g mammalian meat/person/day was below 1% of Adequate Intake (AI) for Mn and between 18.9% and 43.2% of Recommended Dietary Allowance (RDA) for Se.

The Influence of Cu Addition on Dispersoid Formation and Mechanical Properties of Al-Mn-Mg 3004 Alloy

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Zhen Li

2018-03-01

Full Text Available The effect of Cu addition on dispersoid precipitation, mechanical properties and creep resistance was investigated in an Al-Mn-Mg 3004 alloy. The addition of Cu promoted dispersoid precipitation by increasing the number density and decreasing the size of dispersoids. Metastable β′-Mg2Si and Q-AlCuMgSi precipitates were observed during the heating process and both could provide favorable nucleation sites for dispersoid precipitation. The addition of Cu improved the thermal stability of dispersoids during a long-term thermal holding at 350 °C for 500 h. Results of mechanical testing show that the addition of Cu remarkably improved the hardness at room temperature, as well as the yield strength and creep resistance at 300 °C, which was mainly attributed to dispersoid strengthening and Cu solid solution strengthening. The yield strength contribution at 300 °C was quantitatively evaluated based on the dispersoid, solid solution and matrix contributions. It was confirmed that dispersoid strengthening is the main strengthening mechanism in the experimental alloys.

One-step synthesis of graphene nanoribbon-MnO₂ hybrids and their all-solid-state asymmetric supercapacitors.

Science.gov (United States)

Liu, Mingkai; Tjiu, Weng Weei; Pan, Jisheng; Zhang, Chao; Gao, Wei; Liu, Tianxi

2014-04-21

Three-dimensional (3D) hierarchical hybrid nanomaterials (GNR-MnO₂) of graphene nanoribbons (GNR) and MnO₂ nanoparticles have been prepared via a one-step method. GNR, with unique features such as high aspect ratio and plane integrity, has been obtained by longitudinal unzipping of multi-walled carbon nanotubes (CNTs). By tuning the amount of oxidant used, different mass loadings of MnO₂ nanoparticles have been uniformly deposited on the surface of GNRs. Asymmetric supercapacitors have been fabricated with the GNR-MnO₂ hybrid as the positive electrode and GNR sheets as the negative electrode. Due to the desirable porous structure, excellent electrical conductivity, as well as high rate capability and specific capacitances of both the GNR and GNR-MnO₂ hybrid, the optimized GNR//GNR-MnO₂ asymmetric supercapacitor can be cycled reversibly in an enlarged potential window of 0-2.0 V. In addition, the fabricated GNR//GNR-MnO₂ asymmetric supercapacitor exhibits a significantly enhanced maximum energy density of 29.4 W h kg(-1) (at a power density of 12.1 kW kg(-1)), compared with that of the symmetric cells based on GNR-MnO₂ hybrids or GNR sheets. This greatly enhanced energy storage ability and high rate capability can be attributed to the homogeneous dispersion and excellent pseudocapacitive performance of MnO₂ nanoparticles and the high electrical conductivity of the GNRs.

A comparative glycoproteome study of developing endosperm in the hexose-deficient miniature1 (mn1 seed mutant and its wild type Mn1 in maize

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Cecilia eSilva-Sanchez

2014-02-01

Full Text Available In maize developing seeds, transfer cells are prominently located at the basal endosperm transfer layer (BETL. As the first filial cell layer, BETL is a gateway to sugars, nutrients and water from mother plant; and anchor of numerous functions such as sucrose turnover, auxin and cytokinin biosynthesis/accumulation, energy metabolism, defense response, and signaling between maternal and filial generations. Previous studies showed that basal developing endosperms of miniature1 (mn1 mutant seeds lacking the Mn1-encoded cell wall invertase II, are also deficient for hexose. Given the role of glucose as one of the key sugars in protein glycosylation and proper protein folding; we performed a comparative large scale glycoproteome profiling of total proteins of these two genotypes (mn1 mutant vs Mn1 wild type using 2D gel electrophoresis and glycosylation/total protein staining, followed by image analysis. Protein identification was done by LC-MS/MS. A total of 413 spots were detected; from which, 113 spots matched between the two genotypes. Of these, 45 showed > 20% decrease/increase in glycosylation level and were selected for protein identification. A large number of identified proteins showed decreased glycosylation levels in mn1 developing endosperms as compared to the Mn1. Functional classification of proteins, showed mainly of post-translational modification, protein turnover, chaperone activities, carbohydrate and amino acid biosynthesis / transport, and cell wall biosynthesis. These proteins and activities were related to endoplasmic reticulum (ER stress and unfolded protein response (UPR as a result of the low glycolsylation levels of the mutant proteins. Overall, these results provide for the first time a global glycoproteome profile of maize BETL-enriched basal endosperm to better understand their role in seed development in maize.

One-step synthesis of graphene nanoribbon-MnO2 hybrids and their all-solid-state asymmetric supercapacitors

Science.gov (United States)

Liu, Mingkai; Tjiu, Weng Weei; Pan, Jisheng; Zhang, Chao; Gao, Wei; Liu, Tianxi

2014-03-01

Three-dimensional (3D) hierarchical hybrid nanomaterials (GNR-MnO2) of graphene nanoribbons (GNR) and MnO2 nanoparticles have been prepared via a one-step method. GNR, with unique features such as high aspect ratio and plane integrity, has been obtained by longitudinal unzipping of multi-walled carbon nanotubes (CNTs). By tuning the amount of oxidant used, different mass loadings of MnO2 nanoparticles have been uniformly deposited on the surface of GNRs. Asymmetric supercapacitors have been fabricated with the GNR-MnO2 hybrid as the positive electrode and GNR sheets as the negative electrode. Due to the desirable porous structure, excellent electrical conductivity, as well as high rate capability and specific capacitances of both the GNR and GNR-MnO2 hybrid, the optimized GNR//GNR-MnO2 asymmetric supercapacitor can be cycled reversibly in an enlarged potential window of 0-2.0 V. In addition, the fabricated GNR//GNR-MnO2 asymmetric supercapacitor exhibits a significantly enhanced maximum energy density of 29.4 W h kg-1 (at a power density of 12.1 kW kg-1), compared with that of the symmetric cells based on GNR-MnO2 hybrids or GNR sheets. This greatly enhanced energy storage ability and high rate capability can be attributed to the homogeneous dispersion and excellent pseudocapacitive performance of MnO2 nanoparticles and the high electrical conductivity of the GNRs.Three-dimensional (3D) hierarchical hybrid nanomaterials (GNR-MnO2) of graphene nanoribbons (GNR) and MnO2 nanoparticles have been prepared via a one-step method. GNR, with unique features such as high aspect ratio and plane integrity, has been obtained by longitudinal unzipping of multi-walled carbon nanotubes (CNTs). By tuning the amount of oxidant used, different mass loadings of MnO2 nanoparticles have been uniformly deposited on the surface of GNRs. Asymmetric supercapacitors have been fabricated with the GNR-MnO2 hybrid as the positive electrode and GNR sheets as the negative electrode. Due to the

Isothermal sections of Eu(Ca, Zr, Ba)-Mn-Al ternary phase diagrams at 770 K

International Nuclear Information System (INIS)

Manyako, N.B.; Yanson, T.I.; Zarechnyuk, O.S.

1988-01-01

Isothermal cross sections of Eu(Ca, Sr, Ba)-Mn-Al state diagrams at 770 K are plotted by means of X-ray structural analysis. EuMn 2.3-3.6 Al 9.7-8.4 (ThMn 12 structure type) and Eu 2 Mn 5 Al 12 (eigenstructure type) two compound are found within Eu-Mn-Al system. Existance of CaMn 0.16- 0 .32 Al 1.84-1.68 compound (MgNi 2 structure type) is proved and CaMn 3.2-2.1 Al 8.8-9.9 compound (ThMn 12 type partially ordered structure) is found within Ca-Mn-Al system. Ternary compounds are not formed within Sr(Ba)-Mn-Al systems. Regions of stratification, occurring within Eu(Ca, Sr, Ba)-Mn systems, penetrate in ternary system