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1

Weak ferromagnetism in `non-magnetic' austenitic stainless steel  

NASA Astrophysics Data System (ADS)

The magnetization and susceptability of the non-magnetic stainless steels AISI 304 and AISI 316 have been measured at low temperatures using a SQUID magnetometer. A small but stable ferromagnetic component is always present. Field cooling shows the effects of exchange anisotropy. Another stainless steel AISI 321 is non-magnetic at room temperature but it transforms irreversibly to a partially ferromagnetic state when it is cooled below 280 K.

Crangle, John; Fogarty, A.; Taylor, M. J.

1992-06-01

2

STRAIN AGING OF AUSTENITIC HADFIELD MANGANESE STEEL  

E-print Network

STRAIN AGING OF AUSTENITIC HADFIELD MANGANESE STEEL W. S. OWEN1 { and M. GRUJICIC2 1 Department. INTRODUCTION Had®eld manganese steel, here represented by the nominal composition Fe±12Mn±1.2C wt%, is a stable. Noting that manganese decreases the activity of carbon in austenite, they speculated that the relatively

Grujicic, Mica

3

Phase stability of high manganese austenitic steels for cryogenic applications  

Microsoft Academic Search

The aim of this work is to study the austenitic stability against a' martensitic transformation of three non-magnetic austenitic steels : a new stainless steel X2CrMnNiMoN 19-12-11-1 grade, a traditional X8CrMnNiN 19-11-6 grade and a high manganese X8MnCrNi 28-7-1 grade. Measurements of relative magnetic susceptibility at room temperature are performed on strained tensile specimens at 4.2 K. A special extensometer

K Couturier; Stefano Sgobba

2000-01-01

4

Low-carbon manganese carburizing steels  

Microsoft Academic Search

High-manganese low-carbon steels may be a new and promising class of carburizing steels. They do not contain expensive elements or those in short supply, are simple in production, and possess high strength properties and sufficient plasticity of the core. The obtaining in the case of metastable austenite which becomes harder during service opens new possibilities for increasing the life of

L. S. Malinov; L. I. Yakushechkina; E. L. Malinova

1985-01-01

5

Strain Hardening of Hadfield Manganese Steel  

Microsoft Academic Search

The plastic flow behavior of Hadfield manganese steel in uniaxial tension and compression is shown to be greatly influenced\\u000a by transformation plasticity phenomena. Changes in the stress-strain (???) curves with temperature correlate with the observed\\u000a extent of deformation twinning, consistent with a softening effect of twinning as a deformation mechanism and a hardening\\u000a effect of the twinned microstructure. The combined

P. H. Adler; G. B. Olson; W. S. Owen

1986-01-01

6

Phase stability of high manganese austenitic steels for cryogenic applications  

E-print Network

The aim of this work is to study the austenitic stability against a' martensitic transformation of three non-magnetic austenitic steels : a new stainless steel X2CrMnNiMoN 19-12-11-1 grade, a traditional X8CrMnNiN 19-11-6 grade and a high manganese X8MnCrNi 28-7-1 grade. Measurements of relative magnetic susceptibility at room temperature are performed on strained tensile specimens at 4.2 K. A special extensometer for high precision strain measurements at low temperature has been developed at CERN to test specimens up to various levels of plastic strain. Moreover, the high precision strain recording of the extensometer enables a detailed study of the serrated yield phenomena associated with 4.2 K tensile testing and their influence on the evolution of magnetic susceptibility. The results show that high Mn contents increase the stability of the austenitic structure against a' martensitic transformation, while keeping high strength at cryogenic temperature. Moreover, proper elaboration through primary and possi...

Couturier, K

2000-01-01

7

Effect of the concentration of manganese on the wearability of steel  

Microsoft Academic Search

1.We found that manganese added to steels containing 1% C affects their wearability. The wearability of quenched steels (1% C) and the hardness decrease with increasing amounts of manganese, while in annealed steels containing 0.901.20% C, manganese has no effect either on the hardness or the wearability.2.Quenched and undeformed steels are the most wear-resistant.3.The hardness of quenched G13L steel increases

M. A. Babichev; A. A. Velikanova

1964-01-01

8

On the deformation mechanisms in single crystal Hadfield manganese steels  

SciTech Connect

Austenitic manganese steel, so called Hadfield manganese steel, is frequently used in mining and railroad frog applications requiring excessive deformation and wear resistance. Its work hardening ability is still not completely understood. Previous studies attributed the work-hardening characteristics of this material to dynamic strain aging or an imperfect deformation twin, a so-called pseudotwin. Unfortunately, these previous studies have all focused on polycrystalline Hadfield steels. To properly study the mechanisms of deformation in the absence of grain boundary or texture effects, single crystal specimens are required. The purpose of this work is the following: (1) observe the inelastic stress-strain behavior of Hadfield single crystals in orientations where twinning and slip are individually dominating or when they are competing deformation mechanisms; and (2) determine the microyield points of Hadfield single crystals and use micro-mechanical modeling to predict the stress-strain response of a single crystal undergoing micro-twinning.

Karaman, I.; Sehitoglu, H.; Gall, K. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering] [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering; Chumlyakov, Y.I. [Siberian Physical and Technical Inst., Tomsk (Russian Federation). Physics of Plasticity and Strength of Materials Lab.] [Siberian Physical and Technical Inst., Tomsk (Russian Federation). Physics of Plasticity and Strength of Materials Lab.

1998-02-13

9

Microstructural characterization of Hadfield austenitic manganese steel  

Microsoft Academic Search

discussed. The synthesis of the steel was carried out in a high frequency air induction furnace. At first the blend of steel scrap (0.049%C, 0.43%Mn, 0.028%Si, 0.023%P, 0.013%S, 0.003%Al, 0.035%Cr and balance Fe, all in wt.%) and cast iron (4.5%C, 0.043%Mn, 1.05%Si, 0.175%P, 0.043%S and balance Fe, all in wt.%) was heated to 1,580 C and maintained at that temperature

Ashok Kumar Srivastava; Karabi Das

2008-01-01

10

Microstructural and mechanical effects of nickel and manganese on high strength steel weld metals  

E-print Network

Microstructural and mechanical effects of nickel and manganese on high strength steel weld metals E Neural network modelling suggested that the impact strength of high-strength steel weld metals could with respect to Mn. Based on these predictions, shielded metal arc welding was used to prepare weld metals

Cambridge, University of

11

Structure and properties of low-carbon high-manganese cast steels for cryogenic use  

Microsoft Academic Search

A low carbon content and a relatively high manganese\\/carbon ratio have a marked effect in promoting the toughness of Mn-C cast steels at low temperatures. In the case of a low carbon content, cast steel with an austenitic matrix containing epsilon-martensite has good mechanical properties at low temperatures. The advantage of the cast steel with a ..gamma.. + epsilon structure

L. S. Li; C. M. Wayman; G. S. Wei; D. Z. Yang

1982-01-01

12

Manganese biofouling and the corrosion behavior of stainless steel  

Microsoft Academic Search

Manganese? and iron?oxidizing bacteria (MFOB) are widely implicated in microbially influenced corrosion, often in association with sulfate?reducing bacteria (SRB). Traditionally MFOB have been assigned a passive role in the corrosion process, promoting differential aeration cells, and providing oxygen depleted conditions conducive to the growth and corrosive attack of SRB. Recent work, summarized in this article, demonstrates that manganese biofouling alters

W. H. Dickinson; Z. Lewandowski

1996-01-01

13

Low Frequency-SAFT Inspection Methodology for Coarse-Grained Steel Rail Components (Manganese Steel Frogs)  

SciTech Connect

In the rail industry, sections of high strength Manganese steel are employed at critical locations in railroad networks. Ultrasonic inspections of Manganese steel microstructures are difficult to inspect with conventional means, as the propagation medium is highly attenuative, coarse-grained, anisotropic and nonhomogeneous in nature. Current in-service inspection methods are ineffective while pre-service X-ray methods (used for full-volumetric examinations of components prior to shipment) are time-consuming, costly, require special facilities and highly trained personnel for safe operations, and preclude manufacturers from inspecting statistically meaningful numbers of frogs for effective quality assurance. In-service examinations consist of visual inspections only and by the time a defect or flaw is visually detected, the structural integrity of the component may already be compromised, and immediate repair or replacement is required. A novel ultrasonic inspection technique utilizing low frequency ultrasound (100 to 500 kHz) combined with a synthetic aperture focusing technique (SAFT) for effective reduction of signal clutter and noise, and extraction of important features in the data, has proven to be effective for these coarse grained steel components. Results from proof-of-principal tests in the laboratory demonstrate an effective means to detect and localize reflectors introduced as a function of size and depth from the top of the frog rail. Using non-optimal, commercially available transducers coupled with the low-frequency/SAFT approach, preliminary evaluations were conducted to study the effects of the material microstructure on ultrasonic propagation, sensitivity and resolution in thick section frog components with machined side-drilled holes. Results from this study will be presented and discussed.

Diaz, Aaron A.; Andersen, Eric S.; Samuel, Todd J.

2004-11-01

14

Development of fine-grained carbide-particle hardened Hadfield manganese steels: Final report  

Microsoft Academic Search

Three Hadfield Manganese (HM) steels containing different carbon concentrations (1.2%C, 1.4%C and 1.7%C) were hot-and-warm worked (HWW). The microstructures developed consist of relatively fine austenite grains (<10 ..mu..m) with spheroidized carbides. The hot-and-warm worked HM steels were then tested in torsion at intermediate and high temperatures (500 to 950\\/degree\\/C). Ductility, flow stress, stress-strain relations, and microstructural changes were analyzed as

T. Oyama; A. Goldberg; O. D. Sherby

1987-01-01

15

Behavior of nitrogen in a nitrogen-containing chromium-manganese steel during electroslag remelting  

NASA Astrophysics Data System (ADS)

Electroslag remelting of a high-alloyed steel with high contents of nitrogen, chromium, and manganese in an electroslag furnace has been studied. CaF2-MgO-SiO2 slag developed at TsNIITMASh and allowing remelting process at a temperature of 1520-1560C is used as a flux. It is found that electroslag remelting of high-alloyed steels with a high nitrogen concentration does not change the nitrogen content.

Linchevskii, B. V.; Rigina, L. G.; Takhirov, A. A.

2013-06-01

16

Cryogenic mechanical properties of heavy-section weldment in high-manganese austenitic steel  

Microsoft Academic Search

Cryogenic mechanical properties of a heavy-section weldment of high-manganese austenitic steel for the structure of superconducting magnet were evaluated, The heavy-section weld joint with a 200 mm thickness was manufactured by gas tungsten arc welding (GTAW) process using 21Mn-13Cr-5Ni-0.2N-B steel weld material. No cracks were observed in the weld metal. Tensile property and fracture toughness were tested at 4 K.

O. Matsumoto; T. Tsuchiyama; S. Hada

1997-01-01

17

Influence of carbon, manganese and nickel on microstructure and properties of strong steel  

E-print Network

tungsten arc welding and tightly controlled conditions it proved possible to produce weld metals with both procedure. Shielded metal arc welding (SMAW), flux cored arc welding, and submerged arc welding offerInfluence of carbon, manganese and nickel on microstructure and properties of strong steel weld

Cambridge, University of

18

Influence of processing on the cryogenic mechanical properties of high strength high manganese stainless steel  

SciTech Connect

New high strength structural steels have been required for the large superconducting magnets that will be used for the next step test facility for fusion reactor research. The new materials must have high yield strength accompanied with better toughness and better fatigue resistance compared with the conventional nitrogen-strengthened stainless steels such as AISI 304LN and 316LN that were used for the cases of the toroidal field coils for the Large Coil Project. A number of new high manganese austenitic steels have been proposed for new cryogenic structural alloys since they can offer low cost, stable austenite and high strength.

Ogawa, R.; Morris, J.W. Jr.

1983-08-01

19

Mechanical properties of high manganese steels at cryogenic tempeatures  

SciTech Connect

The purpose of this study is to evaluate the cryogenic properties of two kinds of high Mn steels in an attempt to develop a new cryogenic steel with a higher yield strength than 304LN or 316LN. Sample preparation as well as experimental procedure is described. Mechanical temperature-dependent test results are extensively plotted. Among these results are that high Mn steels are strengthened with N additions of more than 0.2% to meet a yield strength of more than 1 GPa at 4 K; that the fracture thoughness of high C and Mn steel increses with increases in the Mn, Ni, and Cu contents; that addition of Cr enhances the yield strength but deteriorates the fracture toughness; and that nitgroen-strengthened high Mn steels and High C and Mn steels high yield strength, excellent ductility and toughness at 4 K, and show sound EB and MIG welded joints. Results for various specific composite proportions are given.

Hotiuchi, T.; Kasamatsu, Y.; Ogawa, R.; Shimada, M.; Tone, S.; Yamaga, M.

1982-01-01

20

Manganese  

MedlinePLUS

... no RDAs for a nutrient, the Adequate Intake (AI) is used as a guide. The AI is the estimated amount of the nutrient that ... assumed to be adequate. The daily Adequate Intake (AI) levels for manganese are: infants birth to 6 ...

21

Structural studies with the use of XRD and Mssbauer spectroscopy of new high Manganese steels  

NASA Astrophysics Data System (ADS)

New high-strength austenitic and austenitic-ferritic manganese steels represent a significant potential in applications for structural components in the automotive and railway industry due to the excellent combination of high mechanical properties and good plasticity. They belong to the group of steels called AHSS (Advanced High Strength Steels) and UHSS (Ultra High Strength Steels). Application of this combination of properties allows a reduction in the weight of vehicles by the use of reduced cross-section components, and thus to reduce fuel consumption. The development and implementation of industrial production of such interesting and promising steel and its use as construction material requires an improvement of their casting properties and susceptibility to deformation in plastic working conditions. In this work, XRD, Transmission Mssbauer Spectroscopy and Conversion Electron Mssbauer Spectroscopy were employed in a study of the new high-manganese steels with a austenite and austenite-ferrite structure. The influence of the plastic deformation parameters on the changes in the structure, distribution of ferrite and disclosure of the presence of carbides was determined. The analysis of phase transformations in various times using CEMS method made possible to reveal their fine details.

Jablonska, Magdalena Barbara

2014-04-01

22

Cryogenic mechanical properties of heavy-section weldment in high-manganese austenitic steel  

SciTech Connect

Cryogenic mechanical properties of a heavy-section weldment of high-manganese austenitic steel for the structure of superconducting magnet were evaluated, The heavy-section weld joint with a 200 mm thickness was manufactured by gas tungsten arc welding (GTAW) process using 21Mn-13Cr-5Ni-0.2N-B steel weld material. No cracks were observed in the weld metal. Tensile property and fracture toughness were tested at 4 K. The yield strength and the fracture toughness value, K{sub Ic}(J), were 1223 - 1278 MPa and 181{approximately} 201 MPam{sup {1/2}} in the weld metal, respectively.

Matsumoto, O.; Tsuchiyama, T.; Hada, S. [Kobe Steel Ltd., Takasago (Japan)] [and others

1997-06-01

23

Structure and properties of low-carbon high-manganese cast steels for cryogenic use  

SciTech Connect

A low carbon content and a relatively high manganese/carbon ratio have a marked effect in promoting the toughness of Mn-C cast steels at low temperatures. In the case of a low carbon content, cast steel with an austenitic matrix containing epsilon-martensite has good mechanical properties at low temperatures. The advantage of the cast steel with a ..gamma.. + epsilon structure over that with a fully austenitic structure lies in the relatively lower alloy content (Cr, Al, Ni, and Mn) in the former, a content that at the same time imparts better casting behavior. The steels studied containing 19-22% have good low-temperature mechanical properties and are therefore suggested for cryogenic purposes.

Li, L.S.; Wayman, C.M.; Wei, G.S.; Yang, D.Z.

1982-12-01

24

The Influence of Temperature-Time Parameter of Welded Joints Thermal Treatment on Strength-Related Characteristics of Chromium-Molybdenum and Low-Alloy Manganese Steels  

Microsoft Academic Search

The article deals with the analysis of the dependence of strength-related characteristics of welded joints from chromium-molybdenum steel (ASTM A335 Grd. P5) and low-alloy manganese steel (S355J2G3 EN10025-2) upon the parameters of heat treatment. Steel mechanical properties after post-weld heat treatment were analyzed. Chromium- molybdenum (Cr - 5 %) steel and structural low-alloy manganese steel (Mn - 1.4 %) was

Algirdas Vaclovas VALIULIS

2007-01-01

25

Wear resistance of high-manganese steel castings  

Microsoft Academic Search

Conclusions 1.To improve the wear resistance of parts made of G13-L steel, the latter has to be paired at as low a temperature as possible.2.Castings (drag buckets, crusher cones and front ladle walls) should not contain more than 0.060.07% P and 0.5%0.6% Si.3.The castings must be inspected for microstructure and impact toughness.

M. A. Guzovskaya; Ya. D. Khorin

1962-01-01

26

Manganese biofouling of stainless steel: Deposition rates and influence on corrosion processes  

SciTech Connect

Corrosion potential (E{sub corr}) for 316L stainless steel coupons was monitored during 9 days in situ exposure to fresh river water. E{sub corr} increased at 300 mV day{sup {minus}1} reaching potentials of +350 mV (SCE) within 48 hours, then remained fixed at this potential. The coulometric reduction technique was used to determine rate and total abundance of cathodically active manganese biofouling during the exposure. A deposition rate of 0.57 mcoul cm{sup {minus}2} d{sup {minus}1} was measured during the initial 7 days, increasing to 3.1 mcoul cm{sup {minus}2} d{sup {minus}1} between day 7 and 9. Based on a one-electron reduction of MnO{sub 2} to MnOOH, 8.8 {micro}g cm{sup {minus}2} electroactive MnO{sub 2} was deposited during the 9 day exposure. Comparison with published data for manganese deposition in drinking water distribution systems suggests rapid biological MnO{sub 2} deposition consistent with the rapid rate of Ennoblement. Deposition rate is used to estimate the potential impact of manganese biofouling on stainless steel pitting.

Dickinson, W.H.; Lewandowski, Z. [Montana State Univ., Bozeman, MT (United States)

1996-11-01

27

High-alloy manganese-aluminum steels for cryogenic applications  

SciTech Connect

The purpose of this study is to explore an austenitic steel in which all the nickel is replaced by managanese and the chromium by moderate amounts of aluminium in order to evaluate it as a new and more economical alloy for cryogenic applications. Fe-(20-40)Mn alloys, both with and without 5 wt% Al, are tested at 300 and 78 K for their tensile and resilient properties. Sample preparation and experimental procedure are described. Test results are both plotted and micrographed. Among them are: that additions of 5 wt% aluminum to binary Fe-(20-40)Mn alloys increase the stability of the austenite; that the additions also provide a large reserve of ductility to the alloys; and also that additions of carbon have a powerful austenitic stabilizing effect and a solid-solution hardening effect on such alloys. Future studies should focus on properties such as weldability and corrosion resistance.

Charles, J.; Berghezan, A.; Charles, J.; Lutts, A.

1982-01-01

28

On the strain hardening and texture evolution in high manganese steels: Experiments and numerical investigation  

NASA Astrophysics Data System (ADS)

We present a systematic investigation on the strain hardening and texture evolution in high manganese steels where twinning induced plasticity (TWIP) plays a significant role for the materials' plastic deformation. Motivated by the stress-strain behavior of typical TWIP steels with compositions of Fe, Mn, and C, we develop a mechanistic model to explain the strain-hardening in crystals where deformation twinning dominates the plastic deformation. The classical single crystal plasticity model accounting for both dislocation slip and deformation twinning are then employed to simulate the plastic deformation in polycrystalline TWIP steels. While only deformation twinning is activated for plasticity, the simulations with samples composed of voronoi grains cannot fully capture the texture evolution of the TWIP steel. By including both twinning deformation and dislocation slip, the model is able to capture both the stress-strain behaviors and the texture evolution in Fe-Mn-C TWIP steel in different boundary-value problems. Further analysis on the strain contributions by both mechanisms suggests that deformation twinning plays the dominant role at the initial stage of plasticity in TWIP steels, and dislocation slip becomes increasingly important at large strains.

Li, Yongqiang; Zhu, Lianchun; Liu, Yao; Wei, Yujie; Wu, Yanxin; Tang, Di; Mi, Zhenli

2013-12-01

29

Oxide Formation Mechanisms in High Manganese Steel Welds  

NASA Astrophysics Data System (ADS)

Oxide inclusions in high-Mn steel welds were analyzed and almost all of which were found to belong to the MnO-Al2O3-SiO2 system. In this study, the inclusions were categorized based on MnS morphology into the following two types: (1) aluminosilicate with a MnS patch, or (2) aluminosilicate with a MnS shell. The most frequently detected was type 1, the formation mechanism of which was investigated using commercially available thermochemical computing software, FactSage (ver. 6.3). The thermodynamic calculations predicted that galaxite (MnAl2O4), tephroite (Mn2SiO4), and MnS could precipitate during solidification. However, because of the fast cooling rate in welding processes, galaxite and tephroite phases were unable to fully crystallize, but rather were supercooled as glassy phases. In order to confirm the validity of the thermodynamic calculations, the composition of the observed inclusions was compared with the MnO-SiO2-Al2O3 ternary phase diagram, resulting in remarkably good agreement. Furthermore, it was found that the type of the oxide inclusions was dependent on their location ( i.e., MnS shell- and MnS patch-type oxides were detected at the dendritic core and interdendritic boundary, respectively). Both types of oxides were occasionally found in one oxide, near the interdendritic boundary. This indicates that the morphology variation originates from the redistribution of solute due to fast solidification.

Kim, Dooyoung; Han, Kyutae; Lee, Bongkeun; Han, Ilwook; Park, Joo Hyun; Lee, Changhee

2014-04-01

30

Ennoblement of Stainless Steel by the Manganese-Depositing Bacterium Leptothrix discophora  

PubMed Central

The noble shift in open-circuit potential exhibited by microbially colonized stainless steel (ennoblement) was investigated by examining the relationship among surface colonization, manganese deposition, and open-circuit potential for stainless steel coupons exposed to batch cultures of the manganese-depositing bacterium Leptothrix discophora. Open-circuit potential shifted from -100 to +330 mV(infSCE) as a biofilm containing 75 nmol of MnO(infx) cm(sup-2) formed on the coupon surface but changed little further with continued MnO(infx) deposition up to 270 nmol cm(sup-2). Increased open-circuit potential corresponded to decreasing Mn(II) concentration in solution and to increased MnO(infx) accumulation and attached cell density on the coupon surfaces. MnO(infx) deposition was attributable to biological activity, and Mn(II) was observed to enhance cell attachment. The experimental results support a mechanism of ennoblement in which open-circuit potential is fixed near +350 mV(infSCE) by the cathodic activity of biomineralized MnO(infx). PMID:16535635

Dickinson, W. H.; Caccavo, F.; Olesen, B.; Lewandowski, Z.

1997-01-01

31

Thermal Growth and Performance of Manganese Cobaltite Spinel Protection Layers on Ferritic Stainless Steel SOFC Interconnects  

SciTech Connect

To protect solid oxide fuel cells (SOFCs) from chromium poisoning and improve metallic interconnect stability, manganese cobaltite spinel protection layers with a nominal composition of Mn1.5Co1.5O4 were thermally grown on Crofer22 APU, a ferritic stainless steel. Thermal, electrical and electrochemical investigations indicated that the spinel protection layers not only significantly decreased the contact area specific resistance (ASR) between a LSF cathode and the stainless steel interconnect, but also inhibited the sub-scale growth on the stainless steel by acting as a barrier to the inward diffusion of oxygen. A long-term thermal cycling test demonstrated excellent structural and thermomechanical stability of these spinel protection layers, which also acted as a barrier to outward chromium cation diffusion to the interconnect surface. The reduction in the contact ASR and prevention of Cr migration achieved by application of the spinel protection layers on ferritic stainless steel resulted in improved stability and electrochemical performance of SOFCs.

Yang, Zhenguo; Xia, Guanguang; Simner, Steven P.; Stevenson, Jeffry W.

2005-08-01

32

Cryogenic S-N Fatigue and Fatigue Crack Propagation Behaviors of High Manganese Austenitic Steels  

NASA Astrophysics Data System (ADS)

In the current study, the S-N fatigue and the fatigue crack propagation (FCP) behaviors of high manganese austenitic steels, including Fe24Mn and Fe22Mn, were studied, and the results were compared with STS304 (Fe-1Si-2Mn-20Cr-10Ni). The S-N fatigue tests were conducted at 298 K and 110 K (25 C and -163 C), respectively, and at an R ratio of 0.1 under a uniaxial loading condition. The FCP tests were conducted at 298 K and 110 K (25 C and -163C), respectively, and at R ratios of 0.1 and 0.5, respectively, using compact tension specimens. The resistance to S-N fatigue of each specimen increased greatly with decreasing temperature from 298 K to 110 K (25 C to -163 C) and showed a strong dependency on the flow stress. The FCP behaviors of the austenitic steels currently studied substantially varied depending on testing temperature, applied ? K (stress intensity factor range), and R ratio. The enhanced FCP resistance was observed for the Fe24Mn and the Fe22Mn specimens particularly in the near-threshold ? K regime, while the enhancement was significant over the entire ? K regimes for the STS304 specimen, with decreasing temperature from 298 K to 110 K (25 C to -163 C). The S-N fatigue and the FCP behaviors of high manganese austenitic steels are compared with STS304 and discussed based on the fractographic and the micrographic observations.

Jeong, Dae-Ho; Lee, Soon-Gi; Jang, Woo-Kil; Choi, Jong-Kyo; Kim, Young-Ju; Kim, Sangshik

2013-10-01

33

Influence of alloy elements on the properties of manganese steel in the 293-4 K temperature range  

SciTech Connect

Austenitic manganese steels are primarily used as substitutes for expensive chrome-nickel steels. Recently, they have been used for various parts, particularly in cryogenic turbine manufacture where rigid requirements are imposed on the magnetic permeability of the materials used. It is known that Fe-C-Mn steels have unique magnetic properties. For example, the magnetic permeability of these steels is not only significantly less than that of chromenickel ones, in contrast to them it is practically independent of temperature in the 293-4/sup 0/K range -- the result of the unordered magnetic structure of Fe-C-Mn steels and the complex magnetic transformations occurring in them in cooling. This paper presents the results of an investigation of the mechanical properties of FeC-Mn steels additionally alloyed with chromium and aluminum at various temperatures.

Ermakov, E.S.; Khoroshailov, V.G.

1985-09-01

34

Influence of explosive density on mechanical properties of high manganese steel explosion hardened  

NASA Astrophysics Data System (ADS)

The explosion hardening tests of high manganese steel were carried out by using two kinds of explosives of the same composition but different density, respectively. The detonation velocities were tested and the relevant mechanical properties were studied. The results show that the stronger single impulse acting on the specimen, the more hardness of surface increases and the more impact toughness decreases. Compared with the explosive of 1.48 g/cm3 density, the hardness, elongation rate, and impact toughness of the sample for triple explosion with explosive of 1.38 g/cm3 density are larger at the same hardening depth. In addition, the tensile strength of the sample for triple explosion with density of 1.38 g/cm3 is higher from the surface to 15 mm below the surface hardened.

Hu, Xiaoyan; Shen, Zhaowu; Liu, Yingbin; Liu, Tiansheng; Wang, Fengying

2013-12-01

35

Microstructural characterization of high-manganese austenitic steels with different stacking fault energies  

SciTech Connect

Microstructures of tensile-deformed high-manganese austenitic steels exhibiting twinning-induced plasticity were analyzed by electron backscatter diffraction pattern observation and X-ray diffraction measurement to examine the influence of differences in their stacking fault energies on twinning activity during deformation. The steel specimen with the low stacking fault energy of 15 mJ/m{sup 2} had a microstructure with a high population of mechanical twins than the steel specimen with the high stacking fault energy (25 mJ/m{sup 2}). The <111> and <100> fibers developed along the tensile axis, and mechanical twinning occurred preferentially in the <111> fiber. The Schmid factors for slip and twinning deformations can explain the origin of higher twinning activity in the <111> fiber. However, the high stacking fault energy suppresses the twinning activity even in the <111> fiber. A line profile analysis based on the X-ray diffraction data revealed the relationship between the characteristics of the deformed microstructures and the stacking fault energies of the steel specimens. Although the variation in dislocation density with the tensile deformation is not affected by the stacking fault energies, the effect of the stacking fault energies on the crystallite size refinement becomes significant with a decrease in the stacking fault energies. Moreover, the stacking fault probability, which was estimated from a peak-shift analysis of the 111 and 200 diffractions, was high for the specimen with low stacking fault energy. Regardless of the difference in the stacking fault energies of the steel specimens, the refined crystallite size has a certain correlation with the stacking fault probability, indicating that whether the deformation-induced crystallite-size refinement occurs depends directly on the stacking fault probability rather than on the stacking fault energies in the present steel specimens. - Highlights: {yields} We studied effects of stacking fault energies on deformed microstructures of steels. {yields} Correlations between texture and occurrence of mechanical twinning are discussed. {yields} Evolutions of dislocations and crystallite are analyzed by line profile analysis.

Sato, Shigeo, E-mail: s.sato@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Kwon, Eui-Pyo [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Imafuku, Muneyuki [Faculty of Engineering, Tokyo City University, Tokyo 158-8557 (Japan); Wagatsuma, Kazuaki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Suzuki, Shigeru [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)

2011-08-15

36

Nanocharacterisation of precipitates in austenite high manganese steels with advanced techniques: HRSTEM and DualEELS mapping  

NASA Astrophysics Data System (ADS)

To achieve optimal mechanical properties in high manganese steels, the precipitation of nanoprecipitates of vanadium and niobium carbides is under investigation. It is shown that under controlled heat treatments between 850C and 950C following hot deformation, few-nanometre precipitates of either carbide can be produced in test steels with suitable contents of vanadium or niobium. The structure and chemistry of these precipitates are examined in detail with a spatial resolution down to better than 1 nm using a newly commissioned scanning transmission electron microscope. In particular, it is shown that the nucleation of vanadium carbide precipitates often occurs at pre-existing titanium carbide precipitates which formed from titanium impurities in the bulk steel. This work will also highlight the links between the nanocharacterisation and changes in the bulk properties on annealing.

Bobynko, J.; Craven, A. J.; McGrouther, D.; MacLaren, I.; Paul, G.

2014-06-01

37

Manganese-Cobalt Mixed Spinel Oxides as Surface Modifiers for Stainless Steel Interconnects of Solid Oxide Fuel Cells  

SciTech Connect

Ferritic stainless steels are promising candidates for interconnect applications in low- and mid-temperature solid oxide fuel cells (SOFCs). A couple of issues however remain for the particular application, including the chromium poisoning due to chromia evaporation, and long-term surface and electrical stability of the scale grown on these steels. Application of a manganese colbaltite spinel protection layer on the steels appears to be an effective approach to solve the issues. For an optimized performance, Mn{sub 1+x}Co{sub 2-x}O{sub 4} (-1 {le} x {le} 2) spinels were investigated against properties relative for protection coating applications on ferritic SOFC interconnects. Overall it appears that the spinels with x around 0.5 demonstrate a good CTE match to ceramic cell components, a relative high electrical conductivity, and a good thermal stability up to 1,250 C. This was confirmed by a long-term test on the Mn{sub 1.5}Co{sub 1.5}O{sub 4} protection layer that was thermally grown on Crofer22 APU, indicating the spinel protection layer not only significantly decreased the contact resistance between a LSF cathode and the stainless steel interconnects, but also inhibited the sub-scale growth on the stainless steels.

Xia, Gordon; Yang, Z Gary; Stevenson, Jeffry W.

2006-11-06

38

Mechanical behaviour of a new automotive high manganese TWIP steel in the presence  

E-print Network

- Resistance Spot welding Résumé : Les aciers TWIP (TWinning Induced Plasticity) à haute teneur en manganèse to suggest solutions for preventing cracking during spot welding of such steels. Keywords: TWIP steels - High, as austenitic steels, they appear to be sensitive to liquid zinc embrittlement during welding, the liquid zinc

Paris-Sud XI, Université de

39

Nitrogen distribution in austenitic high-nitrogen chromium-manganese steel under friction and high-pressure torsion  

NASA Astrophysics Data System (ADS)

Mssbauer spectroscopy and electron microscopic analysis were used to investigate the precipitation of products of cellular decomposition and their dissolution in high-nitrogen chromium-manganese steel FeMn22Cr18N0.8 under room-temperature severe deformation via dry sliding friction and high pressure torsion in Bridgman anvils. It has been established that the nitrogen content increases in interstitial positions in the quenched and pre-aged alloy due to the strain-induced dissolution of chromium nitrides, which are contained in the products of decomposition. Mssbauer analysis showed that the friction-induced dissolution of chromium nitrides occurs at a depth of more than 10 ?m. Aging reduces the amount of nitrogen that occurred in the solid solution upon deformation. This is explained by the additional energy consumed in grinding the decomposition products.

Shabashov, V. A.; Korshunov, L. G.; Sagaradze, V. V.; Kataeva, N. V.; Zamatovskii, A. E.; Litvinov, A. V.; Lyashkov, K. A.

2013-08-01

40

Mild steels coated with 14% manganese covered electrodes (E7-UM-200-K and E1-UM-350): Phenomena at the steel-coating interface  

SciTech Connect

In this work the authors have studied the phenomena in the interface of the coating made on soft carbon steel with electrodes with a high content of manganese. The study has been done with scanning electron microscope and X-rays mapping images. These images show how the alloy elements are distributed in each of the constituent elements presented in the interface, and the nature of these constituents. These results have allowed us to verify that many of the problems that arise in homogeneous joints, as such localised corrosion, low interface resistance, etc., happened, precisely in these regions. As a help to determine the nature of the constituent elements, microhardness measurements have also been made.

Molleda, F. [Escuela Tecnica Superior de Ingenieros Navales de Madrid (UPM) (Spain)]. E-mail: fmolleda@etsin.upm.es; Mora, J. [Escuela Tecnica Superior de Ingenieros Navales de Madrid (UPM) (Spain); Molleda, F.J. [ESAB Iberica (Spain); Carrillo, E. [Escuela Tecnica Superior de Ingenieros Navales de Madrid (UPM) (Spain); Mora, E. [Escuela Tecnica Superior de Ingenieros Navales de Madrid (UPM) (Spain); Mellor, B.G. [University of Southampton (United Kingdom)

2006-12-15

41

Effects of laser-shock processing on the microstructure and surface mechanical properties of hadfield manganese steel  

NASA Astrophysics Data System (ADS)

The effects of laser-shock processing (LSP) on the microstructure, hardness, and residual stress of Hadfield manganese (1 pct C and 14 pct Mn) steels were studied. Laser-shock processing was performed using a Nd: glass phosphate laser with 600 ps pulse width and up to 120 J/pulse energy at power density above 1012 W/cm2. The effects of cold rolling and shot peening were also studied for comparison. Laser-shock processing caused extensive formation of ? hexagonal close-packed (hep) martensite (35 vol pct), producing up to a 130 pct increase of surface hardness. The surface hardness increase was 40 to 60 pct for the shot-peened specimen and about 60 pct for the cold-rolled specimen. The LSP strengthening effect on Hadfield steel was attributed to the combined effects of the partial dislocation/stacking fault arrays and the grain refinement due to the presence of the ?-hcp martensite. For the cold-rolled and shot-peened specimens, the strengthening was a result of ?-hcp martensite and twins with dislocation effects, respectively. Shot peening resulted in a relatively higher compressive residual stress throughout the specimen than LSP.

Chu, J. P.; Rigsbee, J. M.; Bana?, G.; Lawrence, F. V.; Elsayed-Ali, H. E.

1995-06-01

42

High Manganese and Aluminum Steels for the Military and Transportation Industry  

NASA Astrophysics Data System (ADS)

Lightweight advanced high strength steels (AHSS) with aluminum contents between 4 and 12 weight percent have been the subject of intense interest in the last decade because of an excellent combination of high strain rate toughness coupled with up to a 17% reduction in density. Fully austenitic cast steels with a nominal composition of Fe-30%Mn-9%Al-0.9%C are almost 15% less dense than quenched and tempered Cr-Mo steels (SAE 4130) with equivalent strengths and dynamic fracture toughness. This article serves as a review of the tensile and high-strain-rate fracture properties associated mainly with silicon additions to this base composition. In the solution-treated condition, cast steels have high work-hardening rates with elongations up to 64%, room-temperature Charpy V-notch (CVN) impact energies up to 200 J, and dynamic fracture toughness over 700 kJ/m2. Silicon additions in the range of 0.59-1.56% Si have no significant effect on the mechanical properties of solution-treated steels but increased the tensile strength and hardness during aging. For steels aged at 530C to an average hardness of 310 Brinell hardness number, HBW, increasing the amount of silicon from 1.07% to 1.56% decreased the room temperature CVN breaking energy from 92 J to 68 J and the dynamic fracture toughness from 376 kJ/m2 to 265 kJ/m2. Notch toughness is a strong function of phosphorus content, decreasing the solution-treated CVN impact toughness from 200 J in a 0.006% P steel to 28 J in a 0.07% P steel. For age-hardened steels with 1% Si, increasing levels of phosphorus from 0.001% to 0.043% decreased the dynamic fracture toughness from 376 kJ/m2 to 100 kJ/m2.

Bartlett, Laura; Van Aken, David

2014-09-01

43

Effect of high-temperature thermomechanical treatment on the corrosion cracking of aging austenitic manganese steel  

Microsoft Academic Search

On the basis of structural and fractographic investigations the article analyzes the causes of the favorable effect of high-temperature thermomechanical treatment on the corrosion resistance of austenitic aging steel 08G20M3F2 under stress in 3% aqueous solution of sodium chloride. A subgrain structure formed as a result of treatment in the steel and some curving of the grain boundary was encountered.

T. P. Vasechkina; V. V. Sagaradze; N. L. Pecherkina; Yu. I. Filippov

1988-01-01

44

Characterization of Nonmetallic Inclusions in High-Manganese and Aluminum-Alloyed Austenitic Steels  

NASA Astrophysics Data System (ADS)

The effects of Al and Mn contents on the size, composition, and three-dimensional morphologies of inclusions formed in Fe- xMn- yAl ( x = 10 and 20 mass pct, y = 1, 3, and 6 mass pct) steels were investigated to enhance our understanding of the inclusion formation behavior in high Mn-Al-alloyed steels. By assuming that the alumina is a dominant oxide compound, the volume fraction of inclusions estimated from the chemical analysis, i.e., insoluble Al, in the Fe-Mn-3Al steels was larger than the inclusion volume fractions in the Fe-Mn-1Al and Fe-Mn-6Al steels. A similar tendency was found in the analysis of inclusions from a potentiostatic electrolytic extraction method. This finding could be explained from the terminal velocities of the compounds, which was affected by the thermophysical properties of Fe-Mn-Al steels. The inclusions formed in the Fe-Mn-Al-alloyed steels are classified into seven types according to chemistry and morphology: (1) single Al2O3 particle, (2) single AlN or AlON particle, (3) MnAl2O4 single galaxite spinel particle, (4) Al2O3(-Al(O)N) agglomerate, (5) single Mn(S,Se) particle, (6) oxide core with Mn(S,Se) skin (wrap), and (7) Mn(S,Se) core with Al2O3(-Al(O)N) aggregate (or bump). The Mn(S,Se) compounds were formed by the contamination of the steels by Se from the electrolytic Mn. Therefore, the raw materials (Mn) should be used carefully in the melting and casting processes of Fe-Mn-Al-alloyed steels.

Park, Joo Hyun; Kim, Dong-Jin; Min, Dong Joon

2012-07-01

45

Development of high manganese high nitrogen low activation austenitic stainless steels  

NASA Astrophysics Data System (ADS)

Elementally-substituted high Mn, high N steels have been studied as potential low-activation replacements for austenitic stainless steels of the types AISI 316, 320, 321 and FV548. The approach to the metallurgical design of the compositions and prediction of the basic properties is outlined. Experimental casts of the proposed alloys were prepared and their microstructural constitution, stability and basic mechanical properties investigated. The stability against martensitic transformations under deformation and refrigeration was examined. Ageing at 400, 650 and 900 C following solution treatment at 1150C resulted in a fine grain boundary precipitation of TaC accompanied by intragranular and, in some cases, limited a and Laves phase precipitation. Proof stress values of 470-610 MPa and tensile strengths of 750-1000 MPa were obtained and a high tensile ductility was observed. Fatigue resistance appeared to be similar to that of the established steels but the creep rupture strength was lower than expected.

Bott, A. H.; Pickering, F. B.; Butterworth, G. J.

1986-11-01

46

The influence of aluminum and carbon on the abrasion resistance of high manganese steels  

NASA Astrophysics Data System (ADS)

Abrasive wear testing of lightweight, austenitic Fe-Mn-Al-C cast steel has been performed in accordance with ASTM G65 using a dry sand, rubber wheel, abrasion testing apparatus. Testing was conducted on a series of Fe-30Mn-XAl-YC-1Si-0.5Mo chemistries containing aluminum levels from 2.9 to 9.5 wt.% and carbon levels from 0.9 to 1.83 wt.%. Solution treated materials having an austenitic microstructure produced the highest wear resistance. Wear resistance decreased with higher aluminum, lower carbon, and higher hardness after age hardening. In the solution treated condition the wear rate was a strong function of the aluminum to carbon ratio and the wear rate increased with a parabolic dependence on the Al/C ratio, which ranged from 1.8 to 10.2. Examination of the surface wear scar revealed a mechanism of plowing during abrasion testing and this method of material removal is sensitive to work hardening rate. Work hardening behavior was determined from tensile tests and also decreased with increasing Al/C ratio and after aging hardening. The loss of wear resistance is related to short range ordering of Al and C in the solution treated materials and kappa-carbide precipitation in age hardened materials and both contribute to planar slip and lower work hardening rates. A high carbon tool steel (W1) and a bainitic low alloy steel (SAE 8620) were also tested for comparison. A lightweight steel containing 6.5 wt.% Al and 1.2 wt.% C has wear resistance comparable to within 5% of the bainitic SAE 8620 steel forging currently used for the Bradley Fighting Vehicle track shoe and this cast Fe-Mn-Al-C steel, at equivalent tensile properties, would be 10% lighter.

Buckholz, Samuel August

47

Effect of alloying elements on the properties of silicon-manganese steel  

Microsoft Academic Search

The change points of the steel were determined in a Chevenar dilatometer with photographic recording. The hardenability was determined by the end-quench method. The samples for testing the mechanical properties were oversize to allow for grinding. The tensile strength tests were made with samples 6 mm in diameter, the impact tests with Mesnager samples. The carbon concentration through the depth

S. S. Iskhakov

1969-01-01

48

Control of cryogenic intergranular fracture in high-manganese austenitic steels  

Microsoft Academic Search

The sources of cryogenic intergranular embrittlement in high-Mn austenitic steels and the conditions necessary for its control are examined. It is shown that the high-Mn alloys are inherently susceptible to intergranular embrittlement due to both their low grain boundary cohesion and heterogeneous deformation characteristics. Extrinsic sources of embrittlement which could account for the transition behavior are not observed. An Auger

Strum

1986-01-01

49

Carbon determination in carbon-manganese steels under atmospheric conditions by Laser-Induced Breakdown Spectroscopy.  

PubMed

The most sensitive lines of carbon, used nowadays for its determination in steels by laser-induced-breakdown spectroscopy (LIBS), are at vacuum UV and, thereby, LIBS potential is significantly reduced. We suggested the use of the C I 833.51 nm line for carbon determination in low-alloy steels (c(C)~0.186-1.33 wt.%) in air. Double-pulse LIBS with the collinear scheme was performed for maximal enhancement of a carbon emission signal without substantial complication of experimental setup. Since this line is strongly broadened in laser plasma, it overlapped with the closest iron lines greatly. We implemented a PCR method for the construction of a multivariate calibration model under spectral interferences. The model provided a RMSECV = 0.045 wt.%. The predicted carbon content in the rail templet was in an agreement with the reference value obtained by a combustion analyzer within the relative error of 6%. PMID:25321709

Labutin, Timur A; Zaytsev, Sergey M; Popov, Andrey M; Zorov, Nikita B

2014-09-22

50

Laser Cladding Of Chromium-Manganese-Carbon On Low Carbon Steel For Wear Resistance  

NASA Astrophysics Data System (ADS)

A wear-resistant Cr-Mn-C clad was produced on an AISI 1016 substrate by a laser technique using a defocused beam and a powder delivery system. The resulting physical properties were measured and correlated to processing parameters. The tribology and micro-structure of the clads were evaluated and compared to hardened 440-C stainless steel, Stellite 6, and AISI 1016. The laser processed clads were more wear-resistant than the materials they were compared to. The alloy distribution varied within the clads. The variation agreed with predictions of theoretical models of laser molten regions.

Eiholzer, Cheryl R.

1986-11-01

51

Elevated Airborne Exposures of Teenagers to Manganese, Chromium, and Iron from Steel Dust and New York Citys Subway System  

PubMed Central

There is increasing interest in potential health effects of airborne exposures to hazardous air pollutants at relatively low levels. This study focuses on sources, levels, and exposure pathways of manganese, chromium, and iron among inner-city high school students in New York City (NYC) and the contribution of subways. Samples of fine particulate matter (PM2.5) were collected during winter and summer over 48 h periods in a variety of settings including inside homes, outdoors, and personal samples (i.e., sampling packs carried by subjects). PM2.5 samples were also collected in the NYC subway system. For NYC, personal samples had significantly higher concentrations of iron, manganese, and chromium than did home indoor and ambient samples. The ratios and strong correlations between pairs of elements suggested steel dust as the source of these metals for a large subset of the personal samples. Timeactivity data suggested NYC subways as a likely source of these elevated personal metals. In duplicate PM2.5 samples that integrated 8 h of underground subway exposure, iron, manganese, and chromium levels (>2 orders of magnitude above ambient levels) and their ratios were consistent with the elevated personal exposures. Steel dust in the NYC subway system was the dominant source of airborne exposures to iron, manganese, and chromium for many young people enrolled in this study, with the same results expected for other NYC subway riders who do not have occupational exposures to these metals. However, there are currently no known health effects at the exposure levels observed in this study. PMID:14968857

CHILLRUD, STEVEN N.; EPSTEIN, DAVID; ROSS, JAMES M.; SAX, SONJA N.; PEDERSON, DEE; SPENGLER, JOHN D.; KINNEY, PATRICK L.

2011-01-01

52

Mapping Phase Transformations in the Heat-Affected-Zone of Carbon Manganese Steel Welds using Spatially Resolved X-Ray Diffraction  

SciTech Connect

Spatially Resolved X-Ray Diffraction (SRXRD) was used to investigate phase transformations that occur in the heat affected zone (HAZ) of gas tungsten arc (GTA) welds in AISI 1005 carbon-manganese steel. In situ SRXRD experiments performed at the Stanford Synchrotron Radiation Laboratory (SSRL) probed the phases present in the HAZ during welding, and these real-time observations of the HAZ phases were used to construct a map of the phase transformations occurring in the HAZ. This map identified 5 principal phase regions between the liquid weld pool and the unaffected base metal for the carbon-manganese steel studied in this investigation. Regions of annealing, recrystallization, partial transformation and complete transformation to {alpha}-Fe, {gamma}-Fe, and {delta}-Fe phases were identified using SRXRD, and the experimental results were combined with a heat flow model of the weld to investigate transformation kinetics under both positive and negative temperature gradients in the HAZ. From the resulting phase transformation map, the kinetics of phase transformations that occur under the highly non-isothermal heating and cooling cycles produced during welding of steels can now be better understood and modeled.

Elmer, J W; Wong, J; Ressler, T; Palmer, T A

2001-12-04

53

Control of cryogenic intergranular fracture in high-manganese austenitic steels  

SciTech Connect

The sources of cryogenic intergranular embrittlement in high-Mn austenitic steels and the conditions necessary for its control are examined. It is shown that the high-Mn alloys are inherently susceptible to intergranular embrittlement due to both their low grain boundary cohesion and heterogeneous deformation characteristics. Extrinsic sources of embrittlement which could account for the transition behavior are not observed. An Auger electron spectroscopy (AES) study shows no indication of impurity-segregation-induced embrittlement. No grain boundary precipitation is observed, and austenite stabilization does not ensure ductile fracture. The influence of chemistry modifications on the ductile-to-brittle transition behavior were also examined through additions of N, Cr, and C to binary Fe-31 Mn. Nitrogen additions increase the 77K yield strength at a rate of 2200 MPa per weight percent N, and increase the austenite stability, but also increase the susceptibility of ternary alloys to intergranular fracture. Quaternary Cr additions are effective in increasing the N solubility, and lower the transition temperature. Carbon additions result in complete suppression of intergranular fracture at 77K. Qualitatively significant changes in the deformation heterogeneity with chemistry modifications are not observed. The temper-toughening of Fe-Mn-Cr-N alloys is associated with the grain boundary segregation of boron and the redistribution of N. Both boron and carbon are expected to inhibit intergranular fracture through increases in grain boundary cohesion.

Strum, M.J.

1986-12-01

54

Globally sustainable manganese metal production and use  

Microsoft Academic Search

The cradle to grave concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choicessuch as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production

Karen Hagelstein

2009-01-01

55

Investigation of the Effect of Tungsten Substitution on Microstructure and Abrasive Wear Performance of In Situ VC-Reinforced High-Manganese Austenitic Steel Matrix Composite  

NASA Astrophysics Data System (ADS)

Particulate VC-reinforced high-manganese austenitic steel matrix composites with different vanadium and tungsten contents were synthesized by conventional alloying and casting route. Microstructural characterizations showed that the composites processed by in situ precipitation of the reinforcements were composed of V8C7 particulates distributed in an austenitic matrix. It was observed that addition of tungsten to austenite increases work-hardening rate of subsurface layer during pin-on disk wear test. The maximum abrasive wear resistance was achieved at tungsten content equal to 2 wt pct. However, excessive addition of tungsten promoted the formation of W3C phase and reduced the abrasive wear resistance because of decrease in distribution homogeneity and volume fraction of the reinforcing VC particles.

Moghaddam, Emad Galin; Karimzadeh, Neda; Varahram, Naser; Davami, Parviz

2013-08-01

56

Manganese recycling in the United States in 1998  

USGS Publications Warehouse

This report describes the flow and processing of manganese within the U.S. economy in 1998 with emphasis on the extent to which manganese is recycled. Manganese was used mostly as an alloying agent in alloys in which it was a minor component. Manganese was recycled mostly within scrap of iron and steel. A small amount was recycled within aluminum used beverage cans. Very little manganese was recycled from materials being recovered specifically for their manganese content. For the United States in 1998, 218,000 metric tons of manganese was estimated to have been recycled from old scrap, of which 96% was from iron and steel scrap. Efficiency of recycling was estimated as 53% and recycling rate as 37%. Metallurgical loss of manganese was estimated to be about 1.7 times that recycled. This loss was mostly into slags from iron and steel production, from which recovery of manganese has yet to be shown economically feasible.

Jones, Thomas S.

2001-01-01

57

Mapping Phase Transformations in the Heat-Affected-Zone of Carbon Manganese Steel Welds using Spatially Resolved X-Ray Diffraction  

SciTech Connect

Spatially Resolved X-Ray Diffraction (SRXRD) was used to investigate phase transformations that occur in the heat affected zone (HAZ) of gas tungsten arc (GTA) welds in AISI 1005 carbon-manganese steel. In situ SRXRD experiments performed at the Stanford Synchrotron Radiation Laboratory (SSRL) probed the phases present in the HAZ during welding, and these real-time observations of the HAZ phases were used to construct a map of the phase transformations occurring in the HAZ. This map identified 5 principal phase regions between the liquid weld pool and the unaffected base metal. Regions of annealing, recrystallization, partial transformation and complete transformation to {alpha}-Fe, {gamma}-Fe, and {delta}-Fe phases were identified using SRXRD, and the experimental results were combined with a heat flow model of the weld and thermodynamic calculations to compare these results with the important phase transformation isotherms. From the resulting phase transformation map, the kinetics of phase transformations that occur under the highly non-isothermal heating and cooling cycles produced during welding of steels can be better understood and modeled.

Elmer, J W; Wong, J; Ressler, T; Palmer, T A

2002-02-12

58

Serration Phenomena Occurring During Tensile Tests of Three High-Manganese Twinning-Induced Plasticity (TWIP) Steels  

NASA Astrophysics Data System (ADS)

In this study, the serration phenomena of two high-Mn TWIP steels and an Al-added TWIP steel were examined by tensile tests, and were explained by the microstructural evolution including formation of localized Portevin-Le Chatelier deformation bands and twins. In stress-strain curves of the high-Mn steels, serrations started in a fine and short shape, and their height and periodic interval increased with increasing strain, whereas the Al-added steel did not show any serrations. According to digital images of strain rate and strain obtained from a vision strain gage system, deformation bands were initially formed at the upper region of the gage section, and moved downward along the tensile loading direction. The time when the band formation started was matched with the time when one serration occurred in the stress-time curve. This serration behavior was generally explained by dynamic strain aging, which was closely related with the formation of deformation bands.

Hong, Seokmin; Shin, Sang Yong; Lee, Junghoon; Ahn, Dong-Hyun; Kim, Hyoung Seop; Kim, Sung-Kyu; Chin, Kwang-Geun; Lee, Sunghak

2014-02-01

59

Mineral of the month: manganese  

USGS Publications Warehouse

Manganese is one of the most important ferrous metals and one of the few for which the United States is totally dependent on imports. It is a black, brittle element predominantly used in metallurgical applications as an alloying addition, particularly in steel and cast iron production, which together provide the largest market for manganese (about 83 percent). It is also used as an alloy with nonferrous metals such as aluminum and copper. Nonmetallurgical applications of manganese include battery cathodes, soft ferrite magnets used in electronics, micronutrients found in fertilizers and animal feed, water treatment chemicals, and a colorant for bricks and ceramics.

Corathers, Lisa

2005-01-01

60

Influence of alloy composition on the cryogenic mechanical properties of AISI 200 grade high-manganese austenitic steels  

SciTech Connect

Research on the effect of composition on the cryogenic mechanical properties of high-Mn austenitic steels showed that both the yield strength and change of strength with alloy processing increased significantly with increasing interstitial content. Alloy toughness deteriorated if carbon content was raised to 0.1% or higher or if delta-ferrite was retained in the as-cooled alloy. On the basis of these investigations an alloy of nominal composition 18Mn-5Ni-16Cr-0.024C-0.22 N was made and tested at 4K. Both its strength-toughness characteristic and fatigue crack growth properties compared favorably to those of 304LN and 304N cryogenic steels.

Ogawa, R.; Morris, J.W. Jr.

1982-05-01

61

Influence of alloy composition on the cryogenic mechanical properties of AISI 200 grade high-manganese austenitic steels  

Microsoft Academic Search

Research on the effect of composition on the cryogenic mechanical properties of high-Mn austenitic steels showed that both the yield strength and change of strength with alloy processing increased significantly with increasing interstitial content. Alloy toughness deteriorated if carbon content was raised to 0.1% or higher or if delta-ferrite was retained in the as-cooled alloy. On the basis of these

R. Ogawa; J. W. Jr. Morris

1982-01-01

62

Mild steel welding fume causes manganese accumulation and subtle neuroinflammatory changes but not overt neuronal damage in discrete brain regions of rats after short-term inhalation exposure.  

PubMed

Serious questions have been raised by occupational health investigators regarding a possible causal association between neurological effects in welders and the presence of manganese (Mn) in welding fume. Male Sprague-Dawley rats were exposed by inhalation to 40 mg/m(3) of gas metal arc-mild steel (MS) welding fume for 3 h/day for 10 days. Generated fume was collected in the animal chamber during exposure, and particle size, composition, and morphology were characterized. At 1 day after the last exposure, metal deposition in different organ systems and neurological responses in dopaminergic brain regions were assessed in exposed animals. The welding particles were composed primarily of a complex of iron (Fe) and Mn and were arranged as chain-like aggregates with a significant number of particles in the nanometer size range. Mn was observed to translocate from the lungs to the kidney and specific brain regions (olfactory bulb, cortex, and cerebellum) after MS fume inhalation. In terms of neurological responses, short-term MS fume inhalation induced significant elevations in divalent metal ion transporter 1 (Dmt1) expression in striatum and midbrain and significant increases in expression of proinflammatory chemokines (Ccl2, Cxcl2) and cytokines (IL1beta, TNFalpha) in striatum. In addition, mRNA and protein expression of glial fibrillary acidic protein (GFAP) was significantly increased in striatum after MS fume exposure. However, the 10-day MS welding fume inhalation did not cause any changes in dopamine and its metabolites or GABA in dopaminergic brain regions nor did it produce overt neural cell damage as assessed by histopathology. In summary, short-term MS welding fume exposure led to translocation of Mn to specific brain regions and induced subtle changes in cell markers of neuroinflammatory and astrogliosis. The neurofunctional significance of these findings currently is being investigated in longer, more chronic welding fume exposure studies. PMID:19782702

Antonini, James M; Sriram, Krishnan; Benkovic, Stanley A; Roberts, Jenny R; Stone, Samuel; Chen, Bean T; Schwegler-Berry, Diane; Jefferson, Amy M; Billig, Brenda K; Felton, Christopher M; Hammer, Mary Ann; Ma, Fang; Frazer, David G; O'Callaghan, James P; Miller, Diane B

2009-11-01

63

Manganese encephalopathy: utility of early magnetic resonance imaging  

Microsoft Academic Search

The use of magnetic resonance imaging (MRI) provides visual evidence of cerebral deposits of paramagnetic metals. The usefulness of MRI is described in connection with the manganese poisoning of a 44 year old arc welder who had been engaged in the repair and recycling of railroad track made of manganese steel alloy.

K Nelson; J Golnick; T Korn; C Angle

1993-01-01

64

The search for magnetic fields in mercury-manganese stars  

Microsoft Academic Search

Mercury-manganese (HgMn) stars were considered to be non-magnetic, showing no evidence of surface spots. However, recent investigations revealed that some stars in this class possess an inhomogeneous distribution of chemical elements on their surfaces. According to our current understanding, the most probable mechanism of spot formation involves magnetic fields. Taking the advantage of a newly-built polarimeter attached to the HARPS

Vitalii Makaganiuk; Oleg Kochukhov; Nikolai Piskunov; Sandra V. Jeffers; Christopher M. Johns-Krull; Christoph U. Keller; Michiel Rodenhuis; Frans Snik; Henricus C. Stempels; Jeff A. Valenti

2011-01-01

65

46 CFR 56.60-5 - Steel (High temperature applications).  

Code of Federal Regulations, 2012 CFR

...exposure to temperatures above 875 F (468 C), the carbide phase of alloy steels, such as carbon-molybdenum, manganese-molybdenum-vanadium, manganese-chromium-vanadium, and chromium-vanadium, may convert to graphite....

2012-10-01

66

46 CFR 56.60-5 - Steel (High temperature applications).  

Code of Federal Regulations, 2011 CFR

...exposure to temperatures above 875 F (468 C), the carbide phase of alloy steels, such as carbon-molybdenum, manganese-molybdenum-vanadium, manganese-chromium-vanadium, and chromium-vanadium, may convert to graphite....

2011-10-01

67

46 CFR 56.60-5 - Steel (High temperature applications).  

Code of Federal Regulations, 2013 CFR

...exposure to temperatures above 875 F (468 C), the carbide phase of alloy steels, such as carbon-molybdenum, manganese-molybdenum-vanadium, manganese-chromium-vanadium, and chromium-vanadium, may convert to graphite....

2013-10-01

68

46 CFR 56.60-5 - Steel (High temperature applications).  

Code of Federal Regulations, 2010 CFR

...exposure to temperatures above 875 F (468 C), the carbide phase of alloy steels, such as carbon-molybdenum, manganese-molybdenum-vanadium, manganese-chromium-vanadium, and chromium-vanadium, may convert to graphite....

2010-10-01

69

Nurse Outcomes in Magnet and Non-Magnet Hospitals  

PubMed Central

The important goals of Magnet hospitals are to create supportive professional nursing care environments. A recently published paper found little difference in work environments between Magnet and non-Magnet hospitals. The aim of this study was to determine whether work environments, staffing, and nurse outcomes differ between Magnet and non-Magnet hospitals. A secondary analysis of data from a 4-state survey of 26,276 nurses in 567 acute care hospitals to evaluate differences in work environments and nurse outcomes in Magnet and non-Magnet hospitals was conducted. Magnet hospitals had significantly better work environments (t = ?5.29, P < .001) and more highly educated nurses (t = ?2.27, P < .001). Magnet hospital nurses were 18% less likely to be dissatisfied with their job (P < .05) and 13% less likely to report high burnout (P < .05). Magnet hospitals have significantly better work environments than non-Magnet hospitals. The better work environments of Magnet hospitals are associated with lower levels of nurse job dissatisfaction and burnout. PMID:21934430

Kelly, Lesly A.; McHugh, Matthew D.; Aiken, Linda H.

2011-01-01

70

PLC-9 Non Rusting Stainless Steel Column 10" Square with Radius Corners  

E-print Network

PLC-9 Non Rusting Stainless Steel Column 10" Square with Radius Corners Unit includes two lights General Specifications of PLC-9 Column Non Rusting, Non Magnetic Stainless Steel - .125" Thick Dimensions

Duchowski, Andrew T.

71

Magnetic effects at the interface between non-magnetic oxides  

Microsoft Academic Search

The electronic reconstruction at the interface between two insulating oxides can give rise to a highly conductive interface. Here we show how, in analogy to this remarkable interface-induced conductivity, magnetism can be induced at the interface between the otherwise non-magnetic insulating perovskites SrTiO3 and LaAlO3. A large negative magnetoresistance of the interface is found, together with a logarithmic temperature dependence

A. Brinkman; M. Huijben; M. van Zalk; J. Huijben; U. Zeitler; J. C. Maan; W. G. van der Wiel; G. Rijnders; D. H. A. Blank; H. Hilgenkamp

2007-01-01

72

Autonomic function in manganese alloy workers  

SciTech Connect

The observation of orthostatic hypotension in an index case of manganese toxicity lead to this prospective attempt to evaluate cardiovascular autonomic function and cognitive and emotional neurotoxicity in eight manganese alloy welders and machinists. The subjects consisted of a convenience sample consisting of an index case of manganese dementia, his four co-workers in a frog shop for gouging, welding, and grinding repair of high manganese railway track and a convenience sample of three mild steel welders with lesser manganese exposure also referred because of cognitive or autonomic symptoms. Frog shop air manganese samples 9.6--10 years before and 1.2--3.4 years after the diagnosis of the index case exceeded 1.0 mg/m{sup 3} in 29% and 0.2 mg/m{sup 3} in 62%. Twenty-four-hour electrocardiographic (Holter) monitoring was used to determine the temporal variability of the heartrate (RR{prime} interval) and the rates of change at low frequency and high frequency. MMPI and MCMI personality assessment and short-term memory, figure copy, controlled oral word association, and symbol digit tests were used.

Barrington, W.W.; Angle, C.R.; Willcockson, N.K.; Padula, M.A. [Univ. of Nebraska Medical Center, Omaha, NE (United States)] [Univ. of Nebraska Medical Center, Omaha, NE (United States); Korn, T.

1998-07-01

73

Electrochemistry of passive metals modified by manganese oxides deposited by Leptothrix discophora : two-step model verified by ToF-SIMS  

Microsoft Academic Search

We have applied time-of-flight secondary ion mass spectroscopy (ToF-SIMS) to study microbially induced ennoblement of 316L stainless steel and Ti6Al4V surfaces exposed to manganese-oxidizing bacteria Leptothrix discophora SP-6. Our observations indicate that manganese biomineralization occurs in two steps: first, the divalent manganese (Mn2+) is oxidized to manganese oxyhydroxide, MnOOH; then the MnOOH is further oxidized to manganese dioxide, MnO2. Both

Xianming Shi; Recep Avci; Zbigniew Lewandowski

2002-01-01

74

Globally sustainable manganese metal production and use.  

PubMed

The "cradle to grave" concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices-such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also reduces the quantity of solid wastes generated during processing. Secondary aluminum facilities have reported hazardous waste generation management issues due to baghouse dusts from rotary furnaces processing selenium contaminated manganese alloys. Environmental impacts resulting from industry are represented by emission inventories of chemical releases to the air, water, and soil. The U.S. metals industry releases reported to EPA Toxic Release Inventory indicate the primary metals industry is the major source of metal air toxic emissions, exceeding electric utility air toxic emissions. The nonferrous metals industry is reported to be the Organization for Economic Co-operation and Development (OECD) most intensive airborne and land pollution source of bioaccumulative metals. However, total waste emissions from industries in the OECD countries have declined due to improving energy consumption. Emission registers and access are improving around the world. However, environmental databases for metal particulates have low confidence ratings since the majority of air toxic emissions are not reported, not monitored, or are estimated based on worst-case emission factors. Environmental assessments including biological monitoring are necessary to validate mandated particulate metal emission reductions and control technologies during metal processing. PMID:19467569

Hagelstein, Karen

2009-09-01

75

Touchening High Strength Steel by Warm Working.  

National Technical Information Service (NTIS)

The manganese-molybdenum alloy armor plate steel has a high combination of hardness and toughness. The steel is useful in making aircraft landing gears and ordnance parts such as armor plate steels. The steel contains, by weight, of carbon 0.30 percent ma...

E. J. Ripling, R. S. Lindberg

1966-01-01

76

Insensitivity of tunneling anisotropic magnetoresistance to non-magnetic electrodes  

NASA Astrophysics Data System (ADS)

Ferromagnetic electrodes play a crucial role in magnetoresistance effect and spin injection, whereas the essential features of non-magnetic metal electrodes in spintronics are commonly ignored except for their electrical conductivity. Here, we verify that the room-temperature tunneling anisotropic magnetoresistance (TAMR) behavior in antiferromagnet-based [Pt/Co]/IrMn/AlOx/metal (metal = Pt, Au, Cu, Al) junctions is insensitive to the top metal electrodes. Similar out-of-plane signals are detected for different electrodes, in contrast to the varied shapes of in-plane TAMR curves which are most likely attributed to the differences in the multidomain structure of the magnetic electrode. This would add a different dimension to spintronics.

Wang, Y. Y.; Song, C.; Wang, G. Y.; Zeng, F.; Pan, F.

2013-11-01

77

Non-Magnetic, Tough, Corrosion- and Wear-Resistant Knives From Bulk Metallic Glasses and Composites  

NASA Technical Reports Server (NTRS)

Quality knives are typically fabricated from high-strength steel alloys. Depending on the application, there are different requirements for mechanical and physical properties that cause problems for steel alloys. For example, diver's knives are generally used in salt water, which causes rust in steel knives. Titanium diver's knives are a popular alternative due to their salt water corrosion resistance, but are too soft to maintain a sharp cutting edge. Steel knives are also magnetic, which is undesirable for military applications where the knives are used as a tactical tool for diffusing magnetic mines. Steel is also significantly denser than titanium (8 g/cu cm vs. 4.5 g/cu cm), which results in heavier knives for the same size. Steel is hard and wear-resistant, compared with titanium, and can keep a sharp edge during service. A major drawback of both steel and titanium knives is that they must be ground or machined into the final knife shape from a billet. Since most knives have a mirrored surface and a complex shape, manufacturing them is complex. It would be more desirable if the knife could be cast into a net or near-net shape in a single step. The solution to the deficiencies of titanium, steel, and ceramic knives is to fabricate them using bulk metallic glasses (or composites). These alloys can be cast into net or near-net shaped knives with a combination of properties that exceed both titanium and steel. A commercially viable BMG (bulk metallic glass) or composite knife is one that exhibits one or all of the following properties: It is based on titanium, has a self-sharpening edge, can retain an edge during service, is hard, is non-magnetic, is corrosion-resistant against a variety of corrosive environments, is tough (to allow for prying), can be cast into a net-shape with a mirror finish and a complex shape, has excellent wear resistance, and is low-density. These properties can be achieved in BMG and composites through alloy chemistry and processing. For each desired property for knife fabrication and performance, there is an alloy development strategy that optimizes behavior. Although BMG knives have been demonstrated as far back as 1995, they never found commercial success because they had to be ground (which presented problems because the alloys contained beryllium), they weren't low cost (because they weren't cast to a net-shape), they were brittle (because they were made with a low-quality commercial material), and they had extremely poor corrosion resistance (because corrosion was not well-understood in these materials). Ultimately, these shortcomings prevented the widespread commercialization. In the current work, the inventors have applied more than a decade of research on BMGs from Caltech and JPL to develop a better understanding of how to make BMG knives that exhibit an optimal combination of properties, processing and cost. Alloys have been developed based in titanium (and other metals), that exhibit high toughness, high hardness, excellent corrosion resistance, no ferromagnetism, edge-retaining selfsharpening, and the ability to be cast like a plastic using commercially available casting techniques (currently used by commercial companies such as Liquidmetal Technologies and Visser Precision Casting). The inventors argue that depending on the application (diving, military, tactical, utility, etc.) there is an optimal combination of design and alloy composition. Moreover, with new casting technologies not available at the inception of these materials, net-shaped knives can be cast into complex shapes that require no aftermarket forming, except for sharpening using water-cooled polishing wheel. These combinations of discoveries seek to make low-cost BMG knives commercially viable products that have no equal among metal or ceramic knives. Current work at JPL focuses on net-shape casting of these alloys and testing their mechanical properties versus commercially available knives to demonstrate their benefits.

Hoffman, Douglas C.; Potter, Benjamin

2013-01-01

78

Formation of Copper Sulfide Artifacts During Electrolytic Dissolution of Steel  

NASA Astrophysics Data System (ADS)

Based on equilibrium considerations, copper sulfide is not expected to form in manganese-containing steel, yet previous workers reported finding copper sulfide in transmission electron microscope samples which had been prepared by electropolishing. It is proposed that copper sulfide can form during electrolytic dissolution because of the much greater stability of copper sulfide relative to manganese sulfide in contact with an electrolyte containing copper and manganese cations. This mechanism has been demonstrated with aluminum-killed steel samples.

Tan, Jia; Pistorius, P. Chris

2013-06-01

79

Rate-dependent properties of aluminum-manganese and aluminum-magnesium alloys during dynamic strain aging, and of OFHC-copper and 304-stainless steel  

NASA Astrophysics Data System (ADS)

The purpose of this work was to obtain a consistent set of experimental data to evaluate relaxation, creep, and cyclic properties of metallic materials experiencing dynamic strain aging at room temperature. The experimental results were used to corroborate predictions made by Viscoplasticity Theory Based on Overstress (VBO) as modified to account for zero or negative strain rate sensitivity experienced during dynamic strain aging. The modified VBO model predicts that relaxation and creep are present and "normal" during dynamic strain aging. However, few data confirm these predictions. Dynamic strain aging is typically manifested by serrated stress-strain curves (a.k.a. Portevin-LeChatelier effect). Other effects are increased strength with increasing temperature and zero or negative strain rate sensitivity. Zero (negative) strain rate sensitivity is characterized by an unchanged (decreasing) flow stress with a change in strain rate. VBO, a "unified" state variable theory, is not capable of reproducing serrations on the stress-strain curve. Aluminum 3003 and 5005 specimens were tested in an MTS servohydraulic testing machine. Strains were measured by a clip-on extensometer attached to the gage section. Tests included monotonic loading and unloading, strain rate change tests, stress relaxation tests, short-time "cold" creep tests, and cyclic tests between +/-0.8% strain. A statistical evaluation of test results confirmed that the aluminum alloys experienced dynamic strain aging and, as predicted, relaxation and creep are present and "normal." Cyclic hardening, although small, was also evident. Additional room temperature testing using annealed oxygen-free high conductivity copper showed deformation-induced strain rate sensitivity, which is in agreement with predictions made by the modified VBO. Finally, evaluation of the stress-strain curve of 304 stainless steel showed that the unloading was not linear as the slope varied from nearly twice the modulus of elasticity (E) to less than the E. Analysis of the unloading behavior with VBO indicates that the point where the slope equals E corresponds to where the stress equals the equilibrium stress.

Irizarry-Quinones, Hugo

1999-10-01

80

Giant spin Seebeck effect in a non-magnetic material.  

PubMed

The spin Seebeck effect is observed when a thermal gradient applied to a spin-polarized material leads to a spatially varying transverse spin current in an adjacent non-spin-polarized material, where it gets converted into a measurable voltage. It has been previously observed with a magnitude of microvolts per kelvin in magnetically ordered materials, ferromagnetic metals, semiconductors and insulators. Here we describe a signal in a non-magnetic semiconductor (InSb) that has the hallmarks of being produced by the spin Seebeck effect, but is three orders of magnitude larger (millivolts per kelvin). We refer to the phenomenon that produces it as the giant spin Seebeck effect. Quantizing magnetic fields spin-polarize conduction electrons in semiconductors by means of Zeeman splitting, which spin-orbit coupling amplifies by a factor of ?25 in InSb. We propose that the giant spin Seebeck effect is mediated by phonon-electron drag, which changes the electrons' momentum and directly modifies the spin-splitting energy through spin-orbit interactions. Owing to the simultaneously strong phonon-electron drag and spin-orbit coupling in InSb, the magnitude of the giant spin Seebeck voltage is comparable to the largest known classical thermopower values. PMID:22785317

Jaworski, C M; Myers, R C; Johnston-Halperin, E; Heremans, J P

2012-07-12

81

Drinking Water Problems: Iron and Manganese  

E-print Network

concentrations of iron and manganese) Oxidizing filter?manganese greensand or zeolite (use with zeolite coated with manganese oxide. These substances adsorb dis- solved iron and manganese. Synthetic zeolite requires less backwash water and softens water as it removes impurities...

Dozier, Monty; McFarland, Mark L.

2004-02-20

82

76 FR 72164 - Circular Welded Carbon-Quality Steel Pipe From India, the Sultanate of Oman, the United Arab...  

Federal Register 2010, 2011, 2012, 2013

...welded carbon-quality steel pipes and tube, of...i) 1.80 percent of manganese; (ii) 2.25 percent...welded carbon-quality steel pipes and tube, of circular...i) 1.80 percent of manganese; (ii) 2.25 percent...duty order on welded steel pipe and tube from...

2011-11-22

83

Effects of electrochemical-deposition method and microstructure on the capacitive characteristics of nano-sized manganese oxide  

Microsoft Academic Search

The amorphous nano-structured manganese oxide was electrochemically deposited onto a stainless-steel electrode. The structure and surface morphology of the obtained manganese oxide were studied by means of X-ray diffraction analysis and scanning electron microscopy. The capacitive characteristics of the manganese oxide electrodes were investigated by means of cyclic voltammetry and constant current chargedischarge cycling. The morphological and capacitive characteristics of

Takuya Shinomiya; Vinay Gupta; Norio Miura

2006-01-01

84

STEREO non-magnetic chemically peculiar stars (Paunzen+, 2013)  

NASA Astrophysics Data System (ADS)

We have analysed the photometric data obtained with the STEREO spacecraft for 558 non-magnetic chemically peculiar (CP) stars to search for rotational and pulsational variability. Applying the Lomb-Scargle and the phase dispersion minimization methods, we have detected photometric variability for 44 objects from which 35 were previously unknown. The new objects are all bright stars on the ecliptic plane (magnitude range 4.7

Paunzen, E.; Wraight, K. T.; Fossati, L.; Netopil, M.; White, G. J.; Bewsher, D.

2014-03-01

85

Occupational exposure to manganese.  

PubMed Central

The relationship between the degree of exposure and biological effects of manganese was studied in a group of 369 workers employed in the production of ferroalloys. Two other groups of workers, from an electrode plant and from an aluminium rolling mill, served as controls. Mean manganese concentrations at work places where ferroalloys were produced varied from 0-301 to 20-442 mg/m3. The exposure level of the two control groups was from 2 to 30 microgram/m3 and from 0-05 to 0-07 microgram/m3, in the electrode plant and rolling mill respectively. Sixty-two (16-8%) manganese alloy workers showed some signs of neurological impairment. These signs were noticeably less in the two control groups (5-8% and 0%) than in the occupationally exposed group. Subjective symptoms, which are nonspecific but may be symptoms of subclinical manganism, were not markedly different in the three groups. However, in the manganese alloy workers some of the subjective symptoms occurred more frequently in heavier smokers than in light smokers or nonsmokers. Heavier smokers engaged in manganese alloy production showed some of the subjective symptoms more often than heavier smokers from the control groups. PMID:871441

Saric, M; Markicevic, A; Hrustic, O

1977-01-01

86

Thermodynamic and transport properties of non-magnetic particles in magnetic fluids  

E-print Network

Magnetic composites, obtained on associating magnetic fluid with non-magnetic particles, offer interesting opportunities in separations, assemblies and other applications, where the microstructure of the composite can be ...

Tejwani, Saurabh

2009-01-01

87

Scanning of magnetic space groups and the analysis of non-magnetic domain walls.  

PubMed

Similarly to atomic positions in a crystal being fixed, or at least constrained by the space group of that crystal, the displacements of atoms in a domain wall are determined or constrained by the symmetry of the wall given by the sectional layer group of the corresponding domain pair. The sectional layer group can be interpreted as comprised of operations that leave invariant a plane transecting two overlapping structures, the domain states of the two domains adhering to the domain wall. The procedure of determining the sectional layer groups for all orientations and positions of a transecting plane is called scanning of the space group. Scanning of non-magnetic space groups has been described and tabulated. It is shown here that the scanning of magnetic groups can be determined from that of non-magnetic groups. The information provided by scanning of magnetic space groups can be utilized in the symmetry analysis of domain walls in non-magnetic crystals since, for any dichromatic space group, which expresses the symmetry of overlapped structures of two non-magnetic domains, there exists an isomorphic magnetic space group. Consequently, a sectional layer group of a magnetic space group expresses the symmetry of a non-magnetic domain wall. Examples of this are given in the symmetry analysis of ferroelectric domain walls in non-magnetic perovskites. PMID:17703074

Janovec, V; Litvin, D B

2007-09-01

88

Low Mn alloy steel for cryogenic service and method of preparation  

DOEpatents

A ferritic cryogenic steel which has a relatively low (about 4-6%) manganese content and which has been made suitable for use at cryogenic temperatures by a thermal cycling treatment followed by a final tempering. The steel includes 4-6% manganese, 0.02-0.06% carbon, 0.1-0.4% molybdenum and 0-3% nickel.

Morris, Jr., John W. (Berkeley, CA); Niikura, Masakazu (Yokohama, JP)

1981-01-01

89

Manganese, Metallogenium, and Martian Microfossils  

NASA Technical Reports Server (NTRS)

Manganese could easily be considered an abundant element in the Martian regolith, assuming that the composition of martian meteorites reflects the composition of the planet. Mineralogical analyses of 5 SNC meteorites have revealed an average manganese oxide concentration of 0.48%, relative to the 0.1% concentration of manganese found in the Earth's crust. On the Earth, the accumulation of manganese oxides in oceans, soils, rocks, sedimentary ores, fresh water systems, and hydrothermal vents can be largely attributed to microbial activity. Manganese is also a required trace nutrient for most life forms and participates in many critical enzymatic reactions such as photosynthesis. The wide-spread process of bacterial manganese cycling on Earth suggests that manganese is an important element to both geology and biology. Furthermore, there is evidence that bacteria can be fossilized within manganese ores, implying that manganese beds may be good repositories for preserved biomarkers. A particular genus of bacteria, known historically as Metallogenium, can form star-shaped manganese oxide minerals (called metallogenium) through the action of manganese oxide precipitation along its surface. Fossilized structures that resemble metallogenium have been found in Precambrian sedimentary formations and in Cretaceous-Paleogene cherts. The Cretaceous-Paleogene formations are highly enriched in manganese and have concentrations of trace elements (Fe, Zn, Cu, and Co) similar to modern-day manganese oxide deposits in marine environments. The appearance of metallogenium-like fossils associated with manganese deposits suggests that bacteria may be preserved within the minerals that they form. Additional information is contained in the original extended abstract.

Stein, L. Y.; Nealson, K. H.

1999-01-01

90

Tissue Manganese Concentrations in Young Male Rhesus Monkeys following Subchronic Manganese Sulfate Inhalation  

Microsoft Academic Search

High-dose human exposure to manganese results in manganese accumulation in the basal ganglia and dopaminergic neuropa- thology. Occupational manganese neurotoxicity is most frequently linked with manganese oxide inhalation; however, exposure to other forms of manganese may lead to higher body burdens. The objective of this study was to determine tissue manganese con- centrations in rhesus monkeys following subchronic (6 h\\/day,

David C. Dorman; Melanie F. Struve; Marianne W. Marshall; Carl U. Parkinson; R. Arden James; Brian A. Wong

2006-01-01

91

The wear behaviour of duplex treated AISI 5140 steel  

Microsoft Academic Search

Purpose This work aims to investigate the wear behavior of manganese phosphate coating on plasma nitrided AISI 5140 steel. Design\\/methodology\\/approach Prior to manganese phosphate coating, plasma nitriding of substrates was performed at gas mixture of 50 percent H2 and 50 percent N2, for the different treatment parameters. The structural, mechanical and tribological properties of the substrates were determined

Yasar Totik; Akgun Alsaran; Ayhan Celik; Ihsan Efeoglu

2011-01-01

92

Slag Metal Reactions during Submerged Arc Welding of Alloy Steels  

E-print Network

) ) Slag Metal Reactions during Submerged Arc Welding of Alloy Steels U. MITRA and T. W. EAGAR for submerged arc welds made with calcium silicate and manganese silicate fluxes. The results show a strong on slag-metal reac- tions of submerged arc welds involving manganese, silicon, and oxygen transfer.1 -1

Eagar, Thomas W.

93

Experimental Analysis and Modelling of Fe-Mn-Al-C Duplex Steel Mechanical Behaviour  

Microsoft Academic Search

A new variety of duplex steels with high content of manganese and aluminum has been elaborated in Arcelor Research. These steels contain two phases: austenite and ferrite combining the best features of austenitic and ferritic steels. In this work, four duplex steels with different chemical composition and phase volume fraction are studied. The evolution of internal stresses for the two

M. N. Shiekhelsouk; V. Favier; K. Inal; O. Bouaziz; M. Cherkaoui

2007-01-01

94

21 CFR 582.5455 - Manganese glycerophosphate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Manganese glycerophosphate. 582.5455 Section...or Dietary Supplements 1 582.5455 Manganese glycerophosphate. (a) Product. Manganese glycerophosphate. (b) Conditions...

2013-04-01

95

21 CFR 582.5455 - Manganese glycerophosphate.  

...2014-04-01 2014-04-01 false Manganese glycerophosphate. 582.5455 Section...or Dietary Supplements 1 582.5455 Manganese glycerophosphate. (a) Product. Manganese glycerophosphate. (b) Conditions...

2014-04-01

96

21 CFR 582.5455 - Manganese glycerophosphate.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Manganese glycerophosphate. 582.5455 Section...or Dietary Supplements 1 582.5455 Manganese glycerophosphate. (a) Product. Manganese glycerophosphate. (b) Conditions...

2011-04-01

97

21 CFR 582.5455 - Manganese glycerophosphate.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Manganese glycerophosphate. 582.5455 Section...or Dietary Supplements 1 582.5455 Manganese glycerophosphate. (a) Product. Manganese glycerophosphate. (b) Conditions...

2010-04-01

98

21 CFR 582.5455 - Manganese glycerophosphate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Manganese glycerophosphate. 582.5455 Section...or Dietary Supplements 1 582.5455 Manganese glycerophosphate. (a) Product. Manganese glycerophosphate. (b) Conditions...

2012-04-01

99

Internal oxidation of the case on carburized alloys steels  

Microsoft Academic Search

1.In the absence of decarburizing, incomplete hardening of carburized and carbonitrided steels in thin surface layers is induced by internal oxidation of alloying elements chromium, manganese, and silicon.Internal oxidation of carburized steel 30KhGT is accompanied by substantial reduction of the manganese and chromium concentrations in austenite.2.The kinetics of internal oxidation with carbonitriding is substantially affected by the diffusion of

I. Ya. Arkhipov; V. A. Batyrev; M. S. Polotskii

1972-01-01

100

Non-magnetic nano-composites for optical and infrared negative refraction index media  

E-print Network

We develop an approach to use nanostructured plasmonic materials as a non-magnetic negative-refractive index system at optical and near-infrared frequencies. In contrast to conventional negative refraction materials, our design does not require periodicity and thus is highly tolerant to fabrication defects. Moreover, since the proposed materials are intrinsically non-magnetic, their performance is not limited to proximity of a resonance so that the resulting structure has relatively low loss. We develop the analytical description of the relevant electromagnetic phenomena and justify our analytic results via numerical solutions of Maxwell equations.

Robyn Wangberg; Justin Elser; Evgenii E. Narimanov; Viktor A. Podolskiy

2005-06-27

101

The space density of magnetic and non-magnetic cataclysmic variables, and implications for CV evolution  

NASA Astrophysics Data System (ADS)

I will present estimates of the space densities of both non-magnetic and magnetic cataclysmic variables (CVs), based on X-ray flux-limited samples. The measurements can be used to address several questions relevant to the evolution of CVs and to the makeup of Galactic X-ray source populations. I will discuss the implications of these results for the high predicted space density of non-magnetic CVs, the evolutionary relationship between intermediate polars and polars, the fraction of CVs with strongly magnetic white dwarfs, and for the contribution of magnetic CVs to Galactic populations of hard X-ray sources.

Pretorius, M.

2014-07-01

102

Manganese exposures during shielded metal arc welding (SMAW) in an enclosed space.  

PubMed

The work reported here evaluates the effectiveness of various rates of dilution ventilation in controlling welder exposures to manganese in shielded metal arc welding (SMAW) fume when working in enclosed or restricted spaces. Personal and area monitoring using total and respirable sampling techniques, along with multiple analytical techniques, was conducted during the welding operations. With 2000 cubic feet per minute (CFM) (56.63 m3/min) dilution ventilation, personal breathing zone concentrations for the welder using 1/8 inches (3.18 mm) E6010 and E7018 mild steel electrodes were within 75% of the existing threshold limit value (TLV of 0.2 mg/m3 for total manganese and were five times greater than the 2001-2003 proposed respirable manganese TLV of 0.03 mg/m3. Manganese concentrations using high manganese content electrodes were five times greater than those for E6010 and E7018 electrodes. Area samples upstream and downstream of the welder using E6010 and E7018 electrodes exceeded 0.2 mg/m3 manganese. Concentrations inside and outside the welding helmet do not indicate diversion of welding fume by the welding helmet from the welder's breathing zone. There was close agreement between respirable manganese and total manganese fume concentrations. Total fume concentrations measured by gravimetric analysis of matched-weight, mixed cellulose ester filters were comparable to those measured via preweighed PVC filter media. This study indicates that 2000 CFM general dilution ventilation per 29 CFR 1910.252 (c)(2) may not be a sufficient means of controlling respirable manganese exposures for either welders or their helpers in restricted or enclosed spaces. In the absence of site-specific monitoring data indicating otherwise, it is prudent to employ respiratory protection or source capture ventilation for SMAW with E6010, E7018, and high manganese content electrodes rather than depending solely on 2000 CFM general dilution ventilation in enclosed spaces. PMID:16080259

Harris, Michael K; Ewing, William M; Longo, William; DePasquale, Christopher; Mount, Michael D; Hatfield, Richard; Stapleton, Randall

2005-08-01

103

40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Manganese heterocyclic tetraamine complex (generic). ...Substances 721.10003 Manganese heterocyclic tetraamine complex (generic). ...identified generically as manganese heterocyclic tetraamine complex (PMNs...

2010-07-01

104

40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Manganese heterocyclic tetraamine complex (generic). ...Substances 721.10003 Manganese heterocyclic tetraamine complex (generic). ...identified generically as manganese heterocyclic tetraamine complex (PMNs...

2011-07-01

105

Tellurium content of marine manganese oxides and other manganese oxides  

USGS Publications Warehouse

Tellurium in amounts ranging from 5 to 125 parts per million was present in all of 12 samples of manganese oxide nodules from the floor of the Pacific and Indian oceans. These samples represent the first recognized points of high tellurium concentration in a sedimentary cycle. The analyses may lend support to the theory that the minor-element content of seafloor manganese nodules is derived from volcanic emanations.

Lakin, H. W.; Thompson, C. E.; Davidson, D. F.

1963-01-01

106

The Mutagenicity and Carcinogenicity of Inorganic Manganese Compounds: A Synthesis of The Evidence  

Microsoft Academic Search

Manganese (Mn), a naturally occurring element present in many foodstuffs, is an essential trace element with many biological functions. In industry, inorganic Mn compounds have a range of different applications, although the majority of Mn is used to make alloys and steel. For the general population, the major source of exposure to Mn is dietary, although drinking water may constitute

Farida Louise Assem; Philip Holmes; Leonard Stephen Levy

2011-01-01

107

Bacteriogenic manganese oxides.  

PubMed

Microorganisms control the redox cycling of manganese in the natural environment. Although the homogeneous oxidation of Mn(II) to form manganese oxide minerals is slow, solid MnO(2) is the stable form of manganese in the oxygenated portion of the biosphere. Diverse bacteria and fungi have evolved the ability to catalyze this process, producing the manganese oxides found in soils and sediments. Other bacteria have evolved to utilize MnO(2) as a terminal electron acceptor in respiration. This Account summarizes the properties of Mn oxides produced by bacteria (bacteriogenic MnO(2)) and our current thinking about the biochemical mechanisms of bacterial Mn(II) oxidation. According to X-ray absorption spectroscopy and X-ray scattering studies, the MnO(2) produced by bacteria consists of stacked hexagonal sheets of MnO(6) octahedra, but these particles are extremely small and have numerous structural defects, particularly cation vacancies. The defects provide coordination sites for binding exogenous metal ions, which can be adsorbed to a high loading. As a result, bacterial production of MnO(2) influences the bioavailability of these metals in the natural environment. Because of its high surface area and oxidizing power, bacteriogenic MnO(2) efficiently degrades biologically recalcitrant organic molecules to lower-molecular-mass compounds, spurring interest in using these properties in the bioremediation of xenobiotic organic compounds. Finally, bacteriogenic MnO(2) is reduced to soluble Mn(II) rapidly in the presence of exogenous ligands or sunlight. It can therefore help to regulate the bioavailability of Mn(II), which is known to protect organisms from superoxide radicals and is required to assemble the water-splitting complex in photosynthetic organisms. Bioinorganic chemists and microbiologists have long been interested in the biochemical mechanism of Mn(IV) oxide production. The reaction requires a two-electron oxidation of Mn(II), but genetic and biochemical evidence for several bacteria implicate multicopper oxidases (MCOs), which are only known to engage one-electron transfers from substrate to O(2). In experiments with the exosporium of a Mn(II)-oxidizing Bacillus species, we could trap the one-electron oxidation product, Mn(III), as a pyrophosphate complex in an oxygen-dependent reaction inhibited by azide, consistent with MCO catalysis. The Mn(III) pyrophosphate complex can further act as a substrate, reacting in the presence of the exosporium to produce Mn(IV) oxide. Although this process appears to be unprecedented in biology, it is reminiscent of the oxidation of Fe(II) to form Fe(2)O(3) in the ferritin iron storage protein. However, it includes a critical additional step of Mn(III) oxidation or disproportionation. We shall continue to investigate this biochemically unique process with purified enzymes. PMID:19778036

Spiro, Thomas G; Bargar, John R; Sposito, Garrison; Tebo, Bradley M

2010-01-19

108

Apparatus and method for continuous separation of magnetic particles from non-magnetic fluids  

DOEpatents

A magnetic separator vessel (1) for separating magnetic particles from non-magnetic fluid includes a separation chamber having an interior and exterior wall, a top and bottom portion; a magnet (3) having first and second poles (2) positioned adjacent to the exterior wall, wherein the first pole is substantially diametrically opposed to the second pole; a inlet port (5) is directed into the top portion of the separation chamber, wherein the inlet port (5) is positioned adjacent to one of the first and second poles (2), wherein the inlet port (5) is adapted to transfer a mixture into the separation chamber; an underflow port (6) in communication with the bottom portion, wherein the underflow port (6) is adapted to receive the magnetic particles; and an overflow port (9) in communication with the separation chamber, wherein the overflow port (9) is adapted to receive the non-magnetic fluid.

Oder, Robin R. (Export, PA); Jamison, Russell E. (Lower Burrell, PA)

2010-02-09

109

Formation of a non-magnetic metallic iron nitride layer on bcc Fe(100)  

NASA Astrophysics Data System (ADS)

We report the formation of a stable iron nitride thin film following the exposition of an Fe(001) single crystal to atomic N plasma produced by means of a radio-frequency (rf) discharge source. The obtained phase, enabled by N-atomic diffusion into the iron matrix, has been characterized using spectroscopical and structural techniques. The comparison of the experimental results with first-principles calculations sheds light on the formed structure stability. The result is the formation of a metallic non-magnetic protective coating film on the iron substrate with a zinc blende (ZB) structure (?''-FeN). The formed film has high oxidation resistance, metallic character, non-magnetic ground state and good epitaxial growth. Thermal treatment of the iron nitride film shows that, at around 700 K, the FeN is decomposed, resulting in bcc Fe as a consequence of the high diffusivity of N in Fe.

Navo, C.; Capitn, M. J.; lvarez, J.; Miranda, R.; Yndurain, F.

2010-07-01

110

Iron and nitrogen self-diffusion in non-magnetic iron nitrides  

SciTech Connect

The self-diffusion of iron and nitrogen is measured in nm range non-magnetic iron nitride thin films. Two non-magnetic iron nitrides, Fe{sub 2.23}N and FeN, were studied using neutron reflectivity. Neutron reflectivity with a depth resolution in the sub-nm range has a different scattering cross section for isotopes, providing a unique opportunity to measure very small diffusivities. The isotope heterostructure in thin film multilayers [Fe-N/{sup 57}Fe-N]{sub 10} and [Fe-N/Fe-{sup 15}N]{sub 10} were prepared using magnetron sputtering. It was observed that nitrogen diffuses slower than iron although the atomic size of iron is larger than that of nitrogen. It was found that a significantly larger group of N atoms participates in the diffusion process than of Fe, making N diffusion slower than that of Fe.

Gupta, Mukul; Gupta, Ajay [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore-452 001 (India); Gupta, Rachana [Institute of Engineering and Technology, Khandwa Road, Devi Ahilya Vishwavidyalaya, Indore 452 017 (India); Stahn, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Horisberger, M. [Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Wildes, A. [Institut Laue-Langevin, rue des Martyrs, 38042 Grenoble Cedex (France); Tayal, Akhil

2011-12-15

111

Manganese oxidation model for rivers  

USGS Publications Warehouse

The presence of manganese in natural waters (>0.05 mg/L) degrades water-supply quality. A model was devised to predict the variation of manganese concentrations in river water released from an impoundment with the distance downstream. The model is one-dimensional and was calibrated using dissolved oxygen, biochemical oxygen demand, pH, manganese, and hydraulic data collected in the Duck River, Tennessee. The results indicated that the model can predict manganese levels under various conditions. The model was then applied to the Chattahoochee River, Georgia. Discrepancies between observed and predicted may be due to inadequate pH data, precipitation of sediment particles, unsteady flow conditions in the Chattahoochee River, inaccurate rate expressions for the low pH conditions, or their combinations.

Hess, Glen W.; Kim, Byung R.; Roberts, Philip J.W.

1989-01-01

112

FATE OF METHYLCYCLOPENTADIENYL MANGANESE TRICARBONYL  

EPA Science Inventory

Methylcyclopentadienyl manganese tricarbonyl (MMT) has been proposed as an octane booster for unleaded gasoline; such use could result in ecological and human exposure through surface water and ground water ecosystems. o evaluate the environmental risks from MMT, its environmenta...

113

Action of manganese on puberty  

E-print Network

Manganese (Mn) is considered important for normal growth and reproduction. Because Mn can cross the blood brain barrier and accumulate in the hypothalamus, and because it has been suggested that infants and children are potentially more sensitive...

Lee, Bo Yeon

2007-09-17

114

New magnetic materials obtained by ion-exchange reactions from non-magnetic layered perovskites  

Microsoft Academic Search

New layered magnetic materials, (MCl)Ca2Ta3O10 (M = Cu, Fe), have been prepared by ion-exchange reactions of non-magnetic perovskite derivatives, ACa2Ta3O10 (A = Rb, Li), in corresponding anhydrous molten salts. Powder x-ray diffraction patterns of the products are successfully indexed assuming tetragonal symmetry with cell dimensions a = 3.829 and c = 15.533 for Cu, and a = 3.822

H. Kageyama; L. Viciu; G. Caruntu; Y. Ueda; J. B. Wiley

2004-01-01

115

Hot coal gas desulfurization with manganese-based sorbents. Annual report, September 1992--September 1993  

SciTech Connect

The focus of work being performed on Hot Coal Gas Desulfurization at the Morgantown Energy Technology Center is primarily in the use of zinc ferrite and zinc titanate sorbents; however, prior studies at the US Steel Fundamental Research Laboratories in Monroeville, PA, by E. T. Turkdogan indicated that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}O{sub 3}) may be a viable alternative to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc hence it is not as likely to undergo depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron hence the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. In addition, thermodynamic analysis of the manganese-oxygen-sulfur system shows it to be less amenable to sulfation than zinc ferrite. Potential also exists for utilization of manganese at higher temperatures than zinc ferrite or zinc titanate. This Annual Topical Report documents progress in pelletizing and testing via thermo-gravimetric analysis of individual pellet formulations of manganese ore/ alumina combinations and also manganese carbonate/alumina with two binders, dextrin and bentonite. It includes the prior Quarterly Technical Reports which indicate that the manganese carbonate material, being of higher purity than the manganese ore, has a higher degree of sulfur capacity and more rapid absorption kinetics. A 2-inch fixed-bed reactor has been fabricated and is now ready for subjecting pellets to cyclic loading and regeneration.

Hepworth, M.T.

1993-12-01

116

77 FR 19192 - Circular Welded Carbon-Quality Steel Pipe From India: Preliminary Affirmative Countervailing Duty...  

Federal Register 2010, 2011, 2012, 2013

...Welded Carbon-Quality Steel Pipe From India: Preliminary...welded carbon-quality steel pipes and tube, of circular...i) 1.80 percent of manganese; (ii) 2.25 percent...Certain Hot-Rolled Carbon Steel Flat Products from India...also Circular Welded Austenitic Stainless...

2012-03-30

117

76 FR 55031 - Galvanized Steel Wire From the People's Republic of China: Preliminary Affirmative Countervailing...  

Federal Register 2010, 2011, 2012, 2013

...investigation covers galvanized steel wire which is a cold-drawn carbon quality steel product in coils, of solid...hot-dipping or electroplating). Steel products to be included in...indicated: 1.80 percent of manganese, or 1.50 percent of...

2011-09-06

118

Special Features of Steels Alloyed with Nitrogen  

Microsoft Academic Search

The role of nitrogen as an alloying element that stabilizes austenite in steels and makes it possible to replace nickel, manganese, and other austenization promoters without deterioration of mechanical and special properties of the metal is considered. Put into practice this could reduce the volume of mining of the mentioned elements. Methods for introducing nitrogen into iron alloys are described.

M. V. Kostina; O. A. Bannykh; V. M. Blinov

2000-01-01

119

Manganese metallurgy review. Part II: Manganese separation and recovery from solution  

Microsoft Academic Search

Various methods for manganese separation and recovery from solution are reviewed, which are potentially applicable to leach solutions of secondary manganese sources, particularly nickel laterite waste effluents. The main methods include solvent extraction, sulfide precipitation, ion exchange, hydroxide precipitation and oxidative precipitation. These methods are briefly compared and assessed for both purification of manganese solutions and recovery of manganese from

Wensheng Zhang; Chu Yong Cheng

2007-01-01

120

Non-magnetic defects in the bulk of two-dimensional topological insulators  

NASA Astrophysics Data System (ADS)

We found that non-magnetic defects in two-dimensional topological insulators induce bound states of two kinds for each spin orientation: electron- and hole-like states. Depending on the sign of the defect potential these states can be also of two kinds with different distribution of the electron density. The density has a maximum or minimum in the center. A surprising effect caused by the topological order is a singular dependence of the bound-state energy on the defect potential.

Sablikov, Vladimir A.; Sukhanov, Aleksei A.

2014-10-01

121

Spintronic transport of a non-magnetic molecule between magnetic electrodes  

SciTech Connect

The spintronic transport properties of a junction system composed of a non-magnetic molecule sandwiched between ferromagnetic metal electrodes are investigated theoretically using a non-equilibrium Green's function method based on density functional theory. It is revealed that in such a system, the molecular magnetic properties induced by hybridization with the magnetic electrodes play a crucial role. Alignment of the induced molecular spin-split levels is strongly related to the spin injection and tunneling magneto-resistance effects. It is found that in the system with weaker molecule-electrode interaction, stronger spintronic effects of the spin injection and tunneling magneto-resistance are observed.

Kondo, Hisashi, E-mail: kondo@tokyo.rist.or.jp [Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505 (Japan)] [Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505 (Japan); Ohno, Takahisa, E-mail: OHNO.Takahisa@nims.go.jp [Computational Materials Science Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan) [Computational Materials Science Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505 (Japan)

2013-12-02

122

The space density and X-ray luminosity function of non-magnetic cataclysmic variables  

NASA Astrophysics Data System (ADS)

We combine two complete, X-ray flux-limited surveys, the ROSAT Bright Survey (RBS) and the ROSAT North Ecliptic Pole (NEP) survey, to measure the space density (?) and X-ray luminosity function (?) of non-magnetic cataclysmic variables (CVs). The combined survey has a flux limit of FX? 1.1 10-12 erg cm-2 s-1 over most of its solid angle of just over ?, but is as deep as ?10-14 erg cm-2 s-1 over a small area. The CV sample that we construct from these two surveys contains 20 non-magnetic systems. We carefully include all sources of statistical error in calculating ? and ? by using Monte Carlo simulations; the most important uncertainty proves to be the often large errors in distances estimates. If we assume that the 20 CVs in the combined RBS and NEP survey sample are representative of the intrinsic population, the space density of non-magnetic CVs is ?. We discuss the difficulty in measuring ? in some detail - in order to account for biases in the measurement, we have to adopt a functional form for ?. Assuming that the X-ray luminosity function of non-magnetic CVs is a truncated power law, we constrain the power-law index to -0.80 0.05. It seems likely that the two surveys have failed to detect a large, faint population of short-period CVs, and that the true space density may well be a factor of 2 or 3 larger than what we have measured; this is possible, even if we only allow for undetected CVs to have X-ray luminosities in the narrow range 28.7 < log(LX/erg s-1) < 29.7. However, ? as high as 2 10-4 pc-3 would require that the majority of CVs has X-ray luminosities below LX= 4 1028 erg s-1 in the 0.5-2.0 keV band.

Pretorius, Magaretha L.; Knigge, Christian

2012-01-01

123

New layered manganese oxide halides.  

PubMed

The first layered manganese(III) oxide chlorides, Sr2MnO3Cl and Sr4Mn3O8-yCl2, have been synthesised; Sr2MnO3Cl adopts a K2NiF4 type structure with sheets of MnO5 square based pyramids linked through oxygen and separated by SrCl layers; it is the end member of a new family of Ruddlesden-Popper type manganese oxide halides which includes the three-layer member Sr4Mn3O8-yCl2 also reported herein. PMID:12120392

Knee, Christopher S; Weller, Mark T

2002-02-01

124

Magnetostrictive Effects in Technical Magnetism: Manganese Bismuth  

NASA Astrophysics Data System (ADS)

The effects of stresses on the magnetization of systems of fine ferromagnetic particles in non-magnetic matrices are studied. Such magnetic systems are of interest because of possible application to magnetostrictive memory systems utilizing acoustic access methods. A three-dimensional magnetostrictive acoustic memory system in which any location within a solid magnetostrictive storage medium may be accessed for reading or writing, with only four signal wires and no moving parts, is described. Irreversible changes in magnetization due to the application of stresses were measured on solid Terfenol (Tb(,.27)Dy(,.73)Fe(,2)), on fine grains of Terfenol in a KBr matrix and on fine particles of Low Temperature Phase Manganese Bismuth (LTP MnBi) in a Bismuth matrix. The largest observed changes due to the application of ultrasound bursts of 10('7) dynes/cm('2) were 0.3% and 0.25% of saturation magnetization for Terfenol and fine grains of Terfenol respectively, at room temperature. Changes of 0.7% of saturation were observed for LTP MnBi at 120K. A model, based on Preisach diagrams, is developed to describe irreversible changes in magnetization due to arbitrary stress and applied field histories. The predictions of this model are compared with experimental measuremens of irreversible changes due to ultrasound bursts on the major hysteresis loop, on minor hysteresis loops and after previous ultrasound bursts. Reversible changes of 10('-5) of saturation in the magnetization of fine particles of Terfenol were observed due to stresses of 3 x 10('4) dynes/cm('2) at 360kHz, in approximate agreement with the coherent rotation model. Magnetostriction measurements on bulk Terfenol ((lamda) = 1 x 10('-3)) show that 180 degree domain wall motion is not negligible. Directionally solidified near-eutectic MnBi forms a precipitate of long rods of LTP and a high coercivity New Phase (NP) MnBi in a Bi matrix. Apparatus for manufacturing this material is described, and the effect of various heat treatments on particle size, alignment and magnetic phases is discussed. Magnetization measurements for both phases are reported for temperatures from 77K to 300K.

Winter, Calvin

125

Diode laser heat treatment of lithium manganese oxide films  

NASA Astrophysics Data System (ADS)

The crystallization of lithium manganese oxide thin films prepared by radio frequency magnetron sputtering on stainless steel substrates under 10 Pa argon pressure is demonstrated by a laser annealing technique. Laser annealing processes were developed as a function of annealing time and temperature with the objective to form an electrochemically active lithium manganese oxide cathode. It is demonstrated, that laser annealing with 940 nm diode laser radiation and an annealing time of 2000 s at 600 C delivers appropriate parameters for formation of a crystalline spinel-like phase. Characteristic features of this phase could be detected via Raman spectroscopy, showing the characteristic main Raman band at 627 cm-1. Within cyclic voltammetric measurements, the two characteristic redox pairs for spinel lithium manganese oxide in the 4 V region could be detected, indicating that the film was well-crystallized and de-/intercalation processes were reversible. Raman post-analysis of a cycled cathode showed that the spinel-like structure was preserved within the cycling process but mechanical degradation effects such as film cracking were observed via scanning electron microscopy. Typical features for the formation of an additional surface reaction layer could be detected using X-ray photoelectron spectroscopy.

Prll, J.; Kohler, R.; Mangang, A.; Ulrich, S.; Bruns, M.; Seifert, H. J.; Pfleging, W.

2012-04-01

126

Kramers non-magnetic superconductivity in LnNiAsO superconductors.  

PubMed

We investigated a series of nickel-based oxyarsenides LnNiAsO (Ln=La, Ce, Pr, Nd, Sm) compounds. CeNiAsO undergoes two successive anti-ferromagnetic transitions at TN1=9.3K and TN2=7.3K; SmNiAsO becomes an anti-ferromagnet below TN?3.5K; NdNiAsO keeps paramagnetic down to 2K but orders anti-ferromagnetically below TN?1.3K. Superconductivity was observed only in Kramers non-magnetic LaNiAsO and PrNiAsO with Tc=2.7K and 0.93K, respectively. The superconductivity of PrNiAsO is further studied by upper critical field and specific heat measurements, which reveal that PrNiAsO is a weakly coupled Kramers non-magnetic superconductor. Our work confirms that the nickel-based oxyarsenide superconductors are substantially different in mechanism to iron-based ones, and are likely to be described by the conventional superconductivity theory. PMID:25248377

Li, Yuke; Luo, Yongkang; Li, Lin; Chen, Bin; Xu, Xiaofeng; Dai, Jianhui; Yang, Xiaojun; Zhang, Li; Cao, Guanghan; Xu, Zhu-An

2014-10-22

127

Component masses of young, wide, non-magnetic white dwarf binaries in the SDSS DR7  

E-print Network

We present a spectroscopic component analysis of 18 candidate young, wide, non-magnetic, double-degenerate binaries identified from a search of the Sloan Digital Sky Survey Data Release 7 (DR7). All but two pairings are likely to be physical systems. We show SDSS J084952.47+471247.7 + SDSS J084952.87+471249.4 to be a wide DA+DB binary, only the second identified to date. Combining our measurements for the components of 16 new binaries with results for three similar, previously known systems within the DR7, we have constructed a mass distribution for the largest sample to date (38) of white dwarfs in young, wide, non-magnetic, double-degenerate pairings. This is broadly similar in form to that of the isolated field population with a substantial peak around M~0.6 Msun. We identify an excess of ultra-massive white dwarfs and attribute this to the primordial separation distribution of their progenitor systems peaking at relatively larger values and the greater expansion of their binary orbits during the final sta...

Baxter, R B; Parker, Q A; Casewell, S L; Lodieu, N; Burleigh, M R; Lawrie, K A; Kulebi, B; Koester, D; Holland, B R

2014-01-01

128

Kramers non-magnetic superconductivity in LnNiAsO superconductors  

NASA Astrophysics Data System (ADS)

We investigated a series of nickel-based oxyarsenides LnNiAsO (Ln = La, Ce, Pr, Nd, Sm) compounds. CeNiAsO undergoes two successive anti-ferromagnetic transitions at TN1 = 9.3 K and TN2 = 7.3 K SmNiAsO becomes an anti-ferromagnet below TN ≃ 3.5 K NdNiAsO keeps paramagnetic down to 2 K but orders anti-ferromagnetically below TN ≃ 1.3 K. Superconductivity was observed only in Kramers non-magnetic LaNiAsO and PrNiAsO with Tc = 2.7 K and 0.93 K, respectively. The superconductivity of PrNiAsO is further studied by upper critical field and specific heat measurements, which reveal that PrNiAsO is a weakly coupled Kramers non-magnetic superconductor. Our work confirms that the nickel-based oxyarsenide superconductors are substantially different in mechanism to iron-based ones, and are likely to be described by the conventional superconductivity theory.

Li, Yuke; Luo, Yongkang; Li, Lin; Chen, Bin; Xu, Xiaofeng; Dai, Jianhui; Yang, Xiaojun; Zhang, Li; Cao, Guanghan; Xu, Zhu-an

2014-10-01

129

Manganese and welding fume exposure and control in construction.  

PubMed

Overexposure to welding fume constituents, particularly manganese, is of concern in the construction industry due to the prevalence of welding and the scarcity of engineering controls. The control effectiveness of a commercially available portable local exhaust ventilation (LEV) unit was assessed. It consisted of a portable vacuum and a small bell-shaped hood connected by a flexible 2 inch (50.8 mm) diameter hose, in both experimental and field settings. The experimental testing was done in a semienclosed booth at a pipefitter training facility. Five paired trials of LEV control vs. no control, each approximately 1 hr in duration and conducted during two successive welds of 6 inch (152.4 mm) diameter carbon steel pipe were run in random order. Breathing zone samples were collected outside the welding hood during each trial. In the field scenario, full-shift breathing zone samples were collected from two pipefitters welding carbon steel pipe for a chiller installation on a commercial construction project. Eight days of full-shift sampling were conducted on both workers (n = 16), and the LEV was used by one of the two workers on an alternating basis for 7 of the days. All samples were collected with personal sample pumps calibrated at 2 L/min. Filter cassettes were analyzed for total particulate and manganese concentration by a certified laboratory. In the experimental setting, use of the portable LEV resulted in a 75% reduction in manganese exposure (mean 13 microg/m(3) vs. 51 microg/m(3); p < 0.05) and a 60% reduction in total particulate (mean 0.74 mg/m(3) vs. 1.83 mg/m(3); p < 0.05). In the field setting, LEV use resulted in a 53% reduction in manganese exposure (geometric mean 46 microg/m(3) vs. 97 microg/m(3); p < 0.05) but only a 10% reduction in total particulate (geometric mean 4.5 mg/m(3) vs. 5.0 mg/m(3); p > 0.05). These results demonstrate that LEV use can reduce manganese exposure associated with welding tasks in construction. PMID:17963139

Meeker, John D; Susi, Pam; Flynn, Michael R

2007-12-01

130

76 FR 23548 - Galvanized Steel Wire From the People's Republic of China and Mexico: Initiation of Antidumping...  

Federal Register 2010, 2011, 2012, 2013

...exporters of galvanized steel wire from the PRC. The...See Circular Welded Austenitic Stainless Pressure Pipe...producers of galvanized steel wire that do not receive...or electroplating). Steel products to be included... 1.80 percent of manganese, or 1.50...

2011-04-27

131

46 CFR 54.25-10 - Low temperature operation-ferritic steels (replaces UCS-65 through UCS-67).  

Code of Federal Regulations, 2011 CFR

...Note: For high alloy steels refer to 54.25-15. For heat treated steels refer to 54.25-20...67 F., ferritic steels shall be made with fine...practice and shall have an austenitic grain size of...Max. C 1 percent Manganese range 1 percent...

2011-10-01

132

75 FR 1495 - Certain Hot-Rolled Carbon Steel Flat Products From India: Preliminary Results of Countervailing...  

Federal Register 2010, 2011, 2012, 2013

...grades of series 2300 and higher. Ball bearings steels, as defined in the HTS. Tool steels, as defined in the HTS. Silico-manganese (as defined in the HTS) or silicon electrical steel with a silicon level exceeding 2.25...

2010-01-11

133

46 CFR 54.25-10 - Low temperature operation-ferritic steels (replaces UCS-65 through UCS-67).  

Code of Federal Regulations, 2010 CFR

...Note: For high alloy steels refer to 54.25-15. For heat treated steels refer to 54.25-20...67 F., ferritic steels shall be made with fine...practice and shall have an austenitic grain size of...Max. C 1 percent Manganese range 1 percent...

2010-10-01

134

Ionization Ability of Manganese Nanoparticles  

NASA Astrophysics Data System (ADS)

Manganese oxide nanoparticles (Mn-O NPs) were prepared through our novel method as reagents for laser desorption/ionization mass spectrometry (LDI-MS). Through the control of the reaction time in the chemical preparation method (0.5, 1, and 5 h), we succeeded in preparing three different types of manganese oxide particles. The particles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and DC magnetization measurements. These characterization results indicated that the manganese ions oxidized in aqueous alkaline solution, and that the spinel structure was retained for the Mn3O4 phase, which then gradually changed into the MnO2 phase. The mass spectra of substance P (MW = 1347.6) were measured by MALDI-TOF mass spectrometry with Mn-O NPs. The Mn-O NPs that reacted with 3-aminopropyltriethoxysilane(?-APTES) for 1 h or 5 h had higher ionization abilities than those reacted for 0.5 h. These different abilities are attributed to the different crystal structures of the prepared manganese oxides.

Hiroki, Tomoyuki; Shigeoka, Daiki; Kimura, Shinji; Mashino, Toshiyuki; Taira, Shu; Ichiyanagi, Yuko

2011-05-01

135

Manganese and chronic hepatic encephalopathy  

Microsoft Academic Search

SummaryClinical observations and animal studies have raised the hypothesis that increased concentrations of manganese (Mn) in whole blood might lead to accumulation of this metal within the basal ganglia in patients with end-stage liver disease. We studied ten patients with liver failure (and ten controls) by magnetic resonance imaging (MRI) and measurement of Mn in brain tissue of three patients

D Krieger; S Krieger; L Theilmann; O Jansen; P Gass; H Lichtnecker

1995-01-01

136

High-purity steels for utility components: Final report  

SciTech Connect

Four structural steels commonly used for utility components like rotor forgings and pressure vessels have been evaluated in high-purity form with levels of manganese and silicon ranging from zero to conventional levels. When manganese is absent from the high-purity steels, it is found to be desirable to compensate for decreased hardenability by increasing the remaining alloy content. The main benefits of improved purity and low Mn and Si content have been found to be increased fracture toughness, reduced fracture appearance transition temperature (FATT), and improved resistance to temper embrittlement. Some improvement in creep rupture ductility was found to be associated with low Si and Mn contents. Reduced volume fraction of inclusions, mainly sulfides and silicates associated with manganese and silicon, are responsible for the observed improved toughness and ductility characteristics. Transformation (CCT curves), cleanliness, tensile, FATT, creep rupture, and fatigue characteristics were observed on the steels studied. 68 refs., 173 figs., 82 tabs.

Ohhashi, T.; Bodnar, R.L.; Reemsnyder, H.S.; Steigerwalt, R.E.

1987-09-01

137

Comparisons among magnetic and non-magnetic fly ash fractions: Strength development of cement-fly ash mortars  

SciTech Connect

Nowadays the continual increase in energy demand produces higher consumption of coal and lignite and, consequently, in a parallel way, fly ash production steps up. Magnetic extractions from aqueous-fly ash suspensions produced magnetic and non-magnetic fly ash fractions. Several fractions were obtained from an original fly ash (T0), from T0 and further grinding, and from a ground fly ash (T60). Magnetic and non-magnetic samples were characterized: chemical composition, granulometric data, specific gravity and specific surface area. Workability studies on mortars containing these fractions were carried out. Generally, non-magnetic fractions yielded mortars with similar or higher flowability than mortars containing the corresponding magnetic fractions. On the other hand, compressive strength development studies showed that non-magnetic fractions are more pozzolanic than magnetic ones; moreover, optimum replacing percentage of cement by fly ash fractions was 45% for non-mechanically treated samples, whereas for ground fractions optimum values were 30% for non-magnetic samples and 45% for magnetic ones.

Paya, J.; Monzo, J.; Borrachero, M.V.; Peris-Mora, E. [Univ. Politecnica de Valencia (Spain)] [Univ. Politecnica de Valencia (Spain)

1996-12-31

138

Chemical and microbiological studies of sulfide?mediated manganese reduction  

Microsoft Academic Search

Laboratory studies of manganese reduction by naturally occurring reduced inorganic compounds were undertaken, both to study further possible in situ mechanisms of manganese reduction and to examine how manganese redox reactions might be coupled to other biogeochemical processes. Chemical manganese reduction by sulfide (in the presence of excess manganese oxide) was found to be rapid and complete, with all sulfide

David J. Burdige; Kenneth H. Nealson

1986-01-01

139

Tunable double negative band structure from non-magnetic coated rods  

NASA Astrophysics Data System (ADS)

A system of periodic poly-disperse-coated nano-rods is considered. Both the coated nano-rods and the host material are non-magnetic. The exterior nano-coating has a frequency-dependent dielectric constant and the rod has a high dielectric constant. A negative effective magnetic permeability is generated near the Mie resonances of the rods, while the coating generates a negative permittivity through a field resonance controlled by the plasma frequency of the coating and the geometry of the crystal. The explicit band structure for the system is calculated in the subwavelength limit. Tunable pass bands exhibiting negative group velocity are generated and correspond to simultaneously negative effective dielectric permittivity and magnetic permeability. These can be explicitly controlled by adjusting the distance between the rods, the coating thickness and the rod diameters.

Chen, Yue; Lipton, Robert

2010-08-01

140

On the possible turbulence mechanism in accretion disks in non-magnetic binary stars  

E-print Network

The arising of turbulence in gas-dynamic (non-magnetic) accretion disks is a major issue of modern astrophysics. Such accretion disks should be stable against the turbulence generation, in contradiction to observations. Searching for possible instabilities leading to the turbulization of gas-dynamic disks is one of the challenging astrophysical problems. In 2004, we showed that in accretion disks in binary stars the so-called precessional density wave forms and induces additional density and velocity gradients in the disk. Linear analysis of the fluid instability of an accretion disk in a binary system revealed that the presence of the precessional wave in the disk due to tidal interaction with the binary companion gives rise to instability of radial modes with the characteristic growth time of tenths and hundredths of the binary orbital period. The radial velocity gradient in the precessional wave is shown to be responsible for the instability. A perturbation becomes unstable if the velocity variation the pe...

Kurbatov, E P; Kaygorodov, P V

2014-01-01

141

On the properties of non-magnetic peculiar B, A, and early F-type stars  

NASA Astrophysics Data System (ADS)

Analyses of high-dispersion, high signal-to-noise spectra enable stellar astronomers to infer many physical and chemical properties of the stars. This paper summarizes detailed analyses of optical spectra of main-sequence, non-magnetic, peculiar B, A, and early F-stars that we performed using the technique of fine analysis. Our primary interest in studying the chemical composition of individual stars is to understand the details of the abundances in light of the theories which predict deviations from solar abundances. Although most recent abundance studies have used fine analysis, it is likely that in the future more studies will use spectrum synthesis techniques. We therefore also review what has been accomplished, and what problems spectrum synthesis will help solve.

Yce, K.; Adelman, S. J.

2014-11-01

142

Studies on microbiologically influenced corrosion of SS304 by a novel manganese oxidizer, Bacillus flexus.  

PubMed

A manganese oxidizing bacterium was isolated from the surface of steel scraps and biochemical tests and 16S rRNA sequencing analysis confirmed the isolate as Bacillus flexus. Potentiodynamic polarization curves showed ennoblement of open circuit potential, increased passive current, a lowering of breakdown potential, active re-passivation potential and enhanced cathodic current in the presence of B. flexus. Adhesion studies with B. flexus on SS304 specimens with different surface treatments demonstrated decreased adhesion on passivated and FeCl(3) treated specimens due to the removal of MnS inclusions. The present study provides evidence that surface treatment of stainless steels can reduce adhesion of this manganese oxidizing bacterium and decrease the probability of microbiologically influenced corrosion. PMID:21749279

Anandkumar, B; George, R P; Tamilvani, S; Padhy, N; Mudali, U Kamachi

2011-01-01

143

Impact of dietary manganese concentration on status criteria to determine manganese requirement in piglets.  

PubMed

The Mn requirement for pigs is not well established. This study aimed to find criteria for assessing growing piglet supply status for Mn and to determine whether the current Mn recommendations meet the requirements for piglets. Thirty-six weaned male castrated 27-day-old piglets (7.24??0.69?kg) were randomized into six groups of six piglets each and housed individually in stainless steel metabolic cages for 42?days. The piglets were fed a diet based on skimmed milk powder and corn starch with increasing Mn concentrations (0.24; 2; 4; 8; 16; or 32?mg?Mn/kg diet as-fed). In week 6, Mn0.24 led to reduced feed intake (p?Manganese concentrations in blood, liver, kidney, lung, heart, phalanx proximalis, pancreas and skeletal muscle were influenced by the dietary Mn supply (p?Manganese concentrations in the liver, kidney and phalanx proximalis seem to be suitable biomarkers for Mn status. A 4?mg/kg dietary Mn concentration recommended by NRC (1998, Nutrient Requirements of Swine. National Academy Press, Washington DC.) did not fulfil piglet requirements. Under the conditions investigated, 16?mg?Mn/kg diet were necessary to reach a plateau in specific enzyme activity and Mn concentration in organs. PMID:21883497

Pallauf, J; Kauer, C; Most, E; Habicht, S D; Moch, J

2012-12-01

144

Spectroscopic characterization of manganese minerals  

NASA Astrophysics Data System (ADS)

Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals.

Lakshmi Reddy, S.; Padma Suvarna, K.; Udayabhaska Reddy, G.; Endo, Tamio; Frost, R. L.

2014-01-01

145

Neurotoxicity of manganese oxide nanomaterials  

Microsoft Academic Search

Manganese (Mn) toxicity in humans has been observed as manganism, a disease that resembles Parkinsons disease. The mechanism\\u000a of Mn toxicity and the chemical forms that may be responsible for its neurotoxicity are not well understood. We examined the\\u000a toxicity of Mn oxide nanomaterials in a neuronal precursor cell model, using the MTS assay to evaluate mitochondrial function\\u000a in living

Diana M. Stefanescu; Ali Khoshnan; Paul H. Patterson; Janet G. Hering

2009-01-01

146

Iron and manganese in lakes  

Microsoft Academic Search

The role of redox processes in determining the chemistry of iron and manganese is considered systematically. Both metals have soluble reduced forms and insoluble oxyhydroxides which are readily interconverted in the vicinity of a redox boundary. Although the oxyhydroxides are dominant in well-oxygenated waters, measureable concentrations of Fe(II) and Mn(II) can be observed, especially where photochemical reduction occurs. Differences in

William Davison

1993-01-01

147

40 CFR 721.10201 - Cobalt lithium manganese nickel oxide.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Cobalt lithium manganese nickel oxide. 721.10201...Chemical Substances 721.10201 Cobalt lithium manganese nickel oxide. (a) Chemical...chemical substance identified as cobalt lithium manganese nickel oxide (PMN...

2013-07-01

148

40 CFR 721.10201 - Cobalt lithium manganese nickel oxide.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Cobalt lithium manganese nickel oxide. 721.10201...Chemical Substances 721.10201 Cobalt lithium manganese nickel oxide. (a) Chemical...chemical substance identified as cobalt lithium manganese nickel oxide (PMN...

2012-07-01

149

40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Manganese heterocyclic tetraamine complex (generic...Chemical Substances 721.10003 Manganese heterocyclic tetraamine complex (generic...chemical substances identified generically as manganese heterocyclic tetraamine...

2013-07-01

150

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

...2014-07-01 false Barium calcium manganese strontium oxide. 721.10011 Section...Substances 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance...substance identified as barium calcium manganese strontium oxide (PMN...

2014-07-01

151

40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Manganese heterocyclic tetraamine complex (generic...Chemical Substances 721.10003 Manganese heterocyclic tetraamine complex (generic...chemical substances identified generically as manganese heterocyclic tetraamine...

2012-07-01

152

40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).  

...2014-07-01 2014-07-01 false Manganese heterocyclic tetraamine complex (generic...Chemical Substances 721.10003 Manganese heterocyclic tetraamine complex (generic...chemical substances identified generically as manganese heterocyclic tetraamine...

2014-07-01

153

40 CFR 721.10201 - Cobalt lithium manganese nickel oxide.  

...2014-07-01 false Cobalt lithium manganese nickel oxide. 721.10201 Section...Substances 721.10201 Cobalt lithium manganese nickel oxide. (a) Chemical substance...substance identified as cobalt lithium manganese nickel oxide (PMN...

2014-07-01

154

Studies on microbiologically influenced corrosion of SS304 by a novel manganese oxidizer, Bacillus flexus  

Microsoft Academic Search

A manganese oxidizing bacterium was isolated from the surface of steel scraps and biochemical tests and 16S rRNA sequencing analysis confirmed the isolate as Bacillus flexus. Potentiodynamic polarization curves showed ennoblement of open circuit potential, increased passive current, a lowering of breakdown potential, active re-passivation potential and enhanced cathodic current in the presence of B. flexus. Adhesion studies with B.

B. Anandkumar; R. P. George; S. Tamilvani; N. Padhy; U. Kamachi Mudali

2011-01-01

155

Heterogeneous clay-manganese(II) oxidation catalyst  

Microsoft Academic Search

A manganese(II)-Schiff base complex has been heterogenized by its intercalation into clay minerals. The incorporation of the homogeneous manganese(II) complexes in the interlayer space of aluminosilicate mineral is accomplished by a cation exchange process. The obtained clay-manganese(II) composite has been studied by chemical analysis, X-ray diffraction and FT-IR spectroscopy. The new catalytic material has been evaluated as oxidation catalyst. Our

D Gournis; M Louloudi; M. A Karakassides; C Kolokytha; K Mitopoulou; N Hadjiliadis

2002-01-01

156

Comment on Methylcyclopentadienyl Manganese Tricarbonyl as an Antiknock: Composition and Fate of Manganese Exhaust Products  

Microsoft Academic Search

In an article published in the August 1975, Journal of the Air Pollution Control Association entitled Methylcyclopentadienyl Manganese Tricarbonyl as an Antiknock: Composition and Pate of Manganese Exhaust Products, the authors conclude that, use of MMT in gasoline will result in no public health hazards, because of the low toxicity of manganese and because of the very low concentration

Edward J. Calabrese; Alfred Sorensen

1975-01-01

157

Influence of Dietary Manganese on the Pharmacokinetics of Inhaled Manganese Sulfate in Male CD Rats  

Microsoft Academic Search

Concerns exist as to whether individuals with relative manga- nese deficiency or excess may be at increased risk for manganese toxicity following inhalation exposure. The objective of this study was to determine whether manganese body burden influences the pharmacokinetics of inhaled manganese sulfate (MnSO4). Postna- tal day (PND) 10 rats were placed on either a low (2 ppm), sufficient (10

David C. Dorman; Melanie F. Struve; R. Arden James; Brian E. McManus; Marianne W. Marshall; Brian A. Wong

2001-01-01

158

Bacterial Manganese Reduction and Growth with Manganese Oxide as the Sole Electron Acceptor  

Microsoft Academic Search

Microbes that couple growth to the reduction of manganese could play an important role in the biogeochemistry of certain anaerobic environments. Such a bacterium, Alteromonas putrefaciens MR-1, couples its growth to the reduction of manganese oxides only under anaerobic conditions. The characteristics of this reduction are consistent with a biological, and not an indirect chemical, reduction of manganese, which suggest

Charles R. Myers; Kenneth H. Nealson

1988-01-01

159

Role of manganese: Are welders at risk?.  

E-print Network

??Serious concerns exist among welders and occupational health investigators on the possible association between exposure to manganese via welding fumes and neurological effects. One suggestion (more)

Nawrocki, R.P.

2012-01-01

160

Corrosion Behavior of High Nitrogen Nickel-Free Fe-16Cr-Mn-Mo-N Stainless Steels  

NASA Astrophysics Data System (ADS)

The purpose of the current study is to develop austenitic nickel-free stainless steels with lower chromium content and higher manganese and nitrogen contents. In order to prevent nickel-induced skin allergy, cobalt, manganese, and nitrogen were used to substitute nickel in the designed steel. Our results demonstrated that manganese content greater than 14 wt pct results in a structure that is in full austenite phase. The manganese content appears to increase the solubility of nitrogen; however, a lower corrosion potential was found in steel with high manganese content. Molybdenum appears to be able to increase the pitting potential. The effects of Cr, Mn, Mo, and N on corrosion behavior of Fe-16Cr-2Co-Mn-Mo-N high nitrogen stainless steels were evaluated with potentiodynamic tests and XPS surface analysis. The results reveal that anodic current and pits formation of the Fe-16Cr-2Co-Mn-Mo-N high nitrogen stainless steels were smaller than those of lower manganese and nitrogen content stainless steel.

Chao, K. L.; Liao, H. Y.; Shyue, J. J.; Lian, S. S.

2014-04-01

161

Battles with Iron: Manganese in Oxidative Stress Protection*  

PubMed Central

The redox-active metal manganese plays a key role in cellular adaptation to oxidative stress. As a cofactor for manganese superoxide dismutase or through formation of non-proteinaceous manganese antioxidants, this metal can combat oxidative damage without deleterious side effects of Fenton chemistry. In either case, the antioxidant properties of manganese are vulnerable to iron. Cellular pools of iron can outcompete manganese for binding to manganese superoxide dismutase, and through Fenton chemistry, iron may counteract the benefits of non-proteinaceous manganese antioxidants. In this minireview, we highlight ways in which cells maximize the efficacy of manganese as an antioxidant in the midst of pro-oxidant iron. PMID:22247543

Aguirre, J. Dafhne; Culotta, Valeria C.

2012-01-01

162

REGULAR ARTICLE Interaction of nickel and manganese in accumulation  

E-print Network

REGULAR ARTICLE Interaction of nickel and manganese in accumulation and localization in leaves . Hyperaccumulator. Manganese localization . Nickel localization . Phytoremediation . trichomes Introduction More

Sparks, Donald L.

163

Two new young, wide, magnetic + non-magnetic double-degenerate binary systems  

NASA Astrophysics Data System (ADS)

We report the discovery of two, new, rare, wide, double-degenerate binaries that each contain a magnetic and a non-magnetic star. The components of SDSS J092646.88+132134.5 + J092647.00+132138.4 and of SDSS J150746.48+521002.1 + J150746.80+520958.0 have angular separations of only 4.6 arcsec (a 650 au) and 5.1 arcsec (a 750 au), respectively. They also appear to share common proper motions. Follow-up optical spectroscopy has revealed each system to consist of a DA and a H-rich high-field magnetic white dwarf (HFMWD). Our measurements of the effective temperatures and the surface gravities of the DA components reveal both to have larger masses than is typical of field white dwarfs. By assuming that these degenerates have evolved essentially as single stars, owing to their wide orbital separations, we can use them to place limits on the total ages of the stellar systems. These suggest that in each case the HFMWD is probably associated with an early-type progenitor (Minit > 2 M?). We find that the cooling time of SDSS J150746.80+520958.0 (DAH) is lower than might be expected had it followed the evolutionary path of a typical single star. This mild discord is in the same sense as that observed for two of the small number of other HFMWDs for which progenitor mass estimates have been made, RE J0317-853 and EG 59. The mass of the other DAH, SDSS J092646.88+132134.5, appears to be smaller than expected on the basis of single-star evolution. If this object was/is a member of a hierarchical triple system it may have experienced greater mass loss during an earlier phase of its life as a result of its having a close companion. The large uncertainties on our estimates of the parameters of the HFMWDs suggest that a larger sample of these objects is required to firmly identify any trends in their inferred cooling times and progenitor masses. This should shed further light on their formation and on the impact magnetic fields have on the late stages of stellar evolution. To serve as a starting point, we highlight two further candidate young, wide magnetic + non-magnetic double-degenerate systems within SDSS, CBS 229 and SDSS J074853.07+302543.5 + J074852.95+302543.4, which should be subjected to detailed (resolved) spectroscopic follow-up studies.

Dobbie, P. D.; Baxter, R.; Klebi, B.; Parker, Q. A.; Koester, D.; Jordan, S.; Lodieu, N.; Euchner, F.

2012-03-01

164

Room temperature ferromagnetism in non-magnetic doped TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

Room-temperature ferromagnetism in non-magnetic doped TiO2 semiconductor nanoparticles is analyzed in the present work. Undoped and N-doped TiO2 nanoparticles were obtained employing sol-gel procedure using urea as the nitrogen source. The obtained gels were first dried at 70 C and afterwards calcined in air at 300 C. A residual carbon concentration was retained in the samples as a consequence of the organic decomposition process. Post-annealing treatments at 300 C under air and vacuum conditions were also performed. The crystallographic structure of nanoparticles was analyzed by X-ray diffraction, obtaining a single anatase crystalline phase after the calcinations (mean nanoparticle diameters around 5-8 nm). SQUID magnetometry was employed to analyze the magnetic response of the samples. Whereas for the undoped samples synthesized with hydrolysis rate h = 6, paramagnetic like behavior is observed at room temperature, the N-doped nanoparticles (h = 3) show a weak ferromagnetic response (saturation magnetization ?10-3 emu/g). Moreover, a clear reinforcement of the room-temperature ferromagnetism response is found with the post-annealing treatments, in particular that performed in vacuum. Thus, the results indicate the dominant role of the oxygen stoichiometry and the oxygen vacancies in the room temperature ferromagnetic response of these TiO2 nanoparticles.

Gmez-Polo, C.; Larumbe, S.; Pastor, J. M.

2013-05-01

165

Rotating field eddy current probe for characterization of cracking in non-magnetic tubing  

SciTech Connect

A rotating field eddy current probe was built and tested for use in small diameter, non-magnetic tubing. The rotating field probe is a driver/pickup style with two orthogonally wound drive coils and a pancake pickup coil. The driver coils are excited by two sine waves 90{degree} out of phase with each other. The physical arrangement of the drive coils and the 90{degree} phase shift of the excitation waveforms creates a field which rotates in the test piece under the drive coils. Preliminary tests on electrical discharge machined (EDM) notches show that phased based estimates of notch depth are possible. Probes currently used for detection of cracks in tubing produce responses that have proven unreliable for estimating defect depths. This recently developed version of the rotating field eddy current probe produces a bipolar response in the presence of a crack or a notch. Typically, the phase angle of a bipolar eddy current response is easily identified and measured and is used extensively for estimating depths of volumetric defects. Data are shown relating the phase angle of the rotating field probe`s bipolar response to the depth of circumferential EDM notches.

Capobianco, T.E. [Lockheed Martin, Schenectady, NY (United States)

1998-07-01

166

Revealing the Degree of Magnetic Frustration by Non-Magnetic Impurities  

SciTech Connect

Imaging the magnetic fields around a non-magnetic impurity can provide a clear benchmark for quantifying the degree of magnetic frustration. Focusing on the strongly frustrated J{sub 1}-J{sub 2} model and the spatially anisotropic J{sub 1a}-J{sub 1b}-J{sub 2} model, very distinct low energy behaviors reflect different levels of magnetic frustration. In the J{sub 1}-J{sub 2} model, bound magnons appear trapped near the impurity in the ground state and strongly reduce the ordered moments for sites proximal to the impurity. In contrast, local moments in the J{sub 1a}-J{sub 1b}-J{sub 2} model are enhanced on the impurity neighboring sites. These theoretical predictions can be probed by experiments such as nuclear magnetic resonance and scanning tunneling microscopy, and the results can elucidate the role of frustration in antiferromagnets and help narrow the possible models to understand magnetism in the iron pnictdies.

Not Available

2011-08-12

167

The complete set of ASCA X-ray observations of non-magnetic cataclysmic variables  

E-print Network

We present the complete set of thirty four ASCA observations of non-magnetic cataclysmic variables. Timing analysis reveals large X-ray flux variations in dwarf novae in outburst (Z Cam, SS Cyg and SU UMa) and orbital modulation in high inclination systems (including OY Car, HT Cas, U Gem, T Leo). We also found episodes of unusually low accretion rate during quiescence (VW Hyi and SS Cyg). Spectral analysis reveals broad temperature distributions in individual systems, with emission weighted to lower temperatures in dwarf novae in outburst. Absorption in excess of interstellar values is required in dwarf novae in outburst, but not in quiescence. We also find evidence for sub-solar abundances and X-ray reflection in the brightest systems. LS Peg, V426 Oph and EI UMa have X-ray spectra that are distinct from the rest of the sample and all three exhibit candidate X-ray periodicities. We argue that they should be reclassified as intermediate polars. In the case of V345 Pav we found that the X-ray source had been previously misidentified.

Darren S. Baskill; Peter J. Wheatley; Julian P. Osborne

2005-02-16

168

Design of a non-magnetic shielded and integrated electromagnetic tomography system  

NASA Astrophysics Data System (ADS)

The detected signal of an electromagnetic tomography (EMT) system is weak and can be easily disturbed by the capacitance coupling and external magnetic field. In order to improve the performance of the EMT system, simulation of a non-magnetic shield design was done and an integrated EMT system based on a field programmable gate array (FPGA) is presented in this paper. By the orthogonal experiments, the influence of the material, height and inner radius of the shield was investigated according to the uniformity criterion of sensitivity. Besides, the principle for the selection of the shield parameters was put forward. In the present EMT system, a direct digital synthesizer module, digital demodulation module, MCU control module, DA interface module, AD interface module and USB communication module were all integrated in a FPGA chip. The integration of the system is increased and the difficulty of debugging is decreased. The influence of the excitation signal frequency, the sample frequency and the accumulation number of the multiply accumulator intellectual property core on the demodulation was analysed and a general principle was proposed. The system was evaluated and an optimal excitation frequency was chosen. A back-projection algorithm based on a truncated singular value was selected to reconstruct the different distributions, and the speed of reconstruction was 27 frames s-1. The design scheme can be easily transplanted to other electrical tomography systems.

Wang, Chao; Zhang, Junqing; Li, Fanwei; Cui, Ziqiang; Xu, Chuanjin

2011-10-01

169

Non-magnetic impurities to induce magnetism in ?-PbO crystal structure  

NASA Astrophysics Data System (ADS)

A new route to d0 magnetism is established with the help of the first-principles methods. Non-magnetic elements in groups 13 and 14 of the periodic table are found to act as the magnetic centers upon embedding in polycrystalline ?-PbO structure. Thus, the local magnetic moment is generated on the impurity site (1.0\\mu_B and 2.0\\mu_B for elements in groups 13 and 14, respectively) due to p orbitals partially filled with electrons whose on-site spin ordering is governed by the first Hund's rule. The magnetic interactions between impurities are controlled by occupation of the p orbitals so that antiferromagnetic (AFM) ordering occurs between impurities of 2.0\\mu_B while ferromagnetic (FM) ordering occurs between impurities possessing 1.0\\mu_B . With respect to the strength of the magnetic interactions, the atomic radius of impurity is found to be a key element to tune the wave function tails of localized electrons: with the reduction of the atomic radius, the on-site stability of the spin-polarized state grows while losing in the long-range order interactions. However, it has been shown that a suppression of the long-range order interactions can be compensated by higher impurity concentration that is allowed by the shift of the solubility limit to higher magnitude.

Berashevich, J.; Reznik, A.

2013-11-01

170

Are Non-Magnetic Mechanisms Such As Temporal Solar Diameter Variations Conceivable for an Irradiance Variability?  

NASA Astrophysics Data System (ADS)

Irradiance variability has been monitored from space for more than two decades. Even though data come from different sources, it is well established that a temporal variability exists ?0.1%, in phase with the solar cycle. Today, one of the best explanations for such an irradiance variability is provided by the evolution of the solar surface magnetic fields. But if some 90 95% can be reproduced, what would be the origin of the 10 5% left? Non-magnetic effects are conceivable. In this paper we will consider temporal variations of the diameter of the Sun as a possible contributor for the remaining part. Such an approach imposes strong constraints on the solar radius variability. We will show that over a solar cycle, variations of no more than 20 mas of amplitude can be considered. Such a variability far from what is reported by observers conducting measurements by means of ground-based solar astrolabes may explain a little part of the irradiance changes not explained by magnetic features. Further, requirements are needed that may help to reach a conclusion. Dedicated space missions are necessary (for example PICARD, GOLF-NG or SDO, scheduled for a launch around 2008); it is also proposed to reactivate SDS flights for such a purpose.

Rozelot, J. P.; Lefebvre, S.; Pireaux, S.; Ajabshirizadeh, A.

2004-10-01

171

Induced Magneto-transport Effects in Non-magnetic Metals on Yttrium Iron Garnet  

NASA Astrophysics Data System (ADS)

Yttrium iron garnet (YIG) was called ``spin Seebeck insulator,'' for it supports heat-generated pure spin currents. Pt thin film, with strong spin-orbit interaction, is used as a spin current generator or detector based on the spin Hall effect or the inverse spin Hall effect. The combination of these two materials plays a very important role in spintronics. A recent magnetotransport study shows strong evidence of a magnetic proximity effect in thin Pt films deposited on YIG. Here, we present a magneto-transport study of several non-magnetic (NM) metal films (e.g. Pt, Pd) on YIG films grown on gadolinium gallium garnet substrates with laser molecular beam epitaxy. The anisotropic magnetoresistance (AMR) and anomalous Hall effect (AHE) reveal clear ferromagnetic characteristics in NM films. The magnitude of the AHE angle ? in Pd/YIG structure increases with decreasing temperature, while ? in Pt/YIG structure has a sign reversal at an intermediate temperature. Both AMR and AHE have been investigated as the NM film thickness is varied and an optimal effective thickness is identified. The effect of annealing has also been studied and the results are consistent with the observed thickness dependence. In thin NM films, a ln(T) temperature dependence with a resistivity minimum is observed at low temperatures, suggesting that the Kondo effect may be relevant. Detailed discussions about the origin of these effects will be presented.

Lin, Tao; Tang, Chi; Shi, Jing

2013-03-01

172

Instability of a magnetoelastic layer resting on a non-magnetic substrate  

NASA Astrophysics Data System (ADS)

Magnetorheological elastomers (MREs) are ferromagnetic particle impregnated rubbers whose mechanical properties are altered by the application of external magnetic fields. Due to their coupled magneto-mechanical response, MREs are finding an increasing number of engineering applications. One such application is in haptics, where the goal is to actively control surface roughness. One way to achieve this is by exploiting the unstable regime of MRE substrate/layer assemblies subjected to transverse magnetic fields. In this work, we study the response of such an assembly subjected to a transverse magnetic field and in-plane stress. The layer is made up of a transversely isotropic MRE material, whose energy density has been obtained experimentally, while the substrate is a non-magnetic isotropic pure polymer/gel. An analytical solution to this problem based on a general, finite strain, 2D continuum modeling for both the MRE layer and the substrate shows that for adequately soft substrates there is a finite-wavelength buckling mode under a transverse magnetic field. Moreover, the critical magnetic field can be substantially reduced in the presence of a compressive stress of the assembly, thus opening the possibility for haptic applications operating under low magnetic fields.

Danas, K.; Triantafyllidis, N.

2014-09-01

173

Are non-magnetic mechanisms such as temporal solar diameter variations conceivable for an irradiance variability?  

E-print Network

Irradiance variability has been monitored from space for more than two decades. Even if data are coming from different sources, it is well established that a temporal variability exists which can be set to as approximately 0.1%, in phase with the solar cycle. Today, one of the best explanation for such an irradiance variability is provided by the evolution of the solar surface magnetic fields. But if some 90 to 95% can be reproduced, what would be the origin of the 10 to 5% left? Non magnetic effects are conceivable. In this paper we will consider temporal variations of the diameter of the Sun as a possible contributor for the remaining part. Such an approach imposes strong constraints on the solar radius variability. We will show that over a solar cycle, variations of no more than 20 mas of amplitude can be considered. Such a variability (far from what is reported by observers conducting measurements by means of ground-based solar astrolabes) may explain a little part of the irradiance changes not explained by magnetic features. Further requirements are needed that may help to reach a conclusion. Dedicated space missions are necessary (for example PICARD, GOLF-NG or SDO, scheduled for a launch around 2008); it is also proposed to reactivate SDS flights for such a purpose.

J. P. Rozelot; S. Lefebvre; S. Pireaux; A. Ajabshirizadeh

2006-01-05

174

Metallurgical aspects in cold rolled high strength steel sheets  

Microsoft Academic Search

Cold rolled high strength steel sheets with yield strength from 300 to 500 N\\/mm2 have been developed by using conventional equipment for producing commercial cold rolled steel sheet, that is, cold rolling,\\u000a box annealing, and temper rolling. Effective alloying elements for strengthening are carbon, silicon, manganese, phosphorus,\\u000a niobium, etc. The sheets up to 400 N\\/mm2 yield strength grade are easily

Takashi Matsuoka; Kakunosuke Yamamori

1975-01-01

175

Heat-affected zone cracking of nitronic 60 stainless steel  

Microsoft Academic Search

Nitronic 60 is a nitrogen-strengthened austenitic stainless steel used for applications where metal-to-metal wear and galling resistance are required. In addition, it does not transfer to martensite with strain or upon cooling to cryogenic temperatures. In comparison to type 304 stainless steel, the nickel content is similar, chromium content is slightly reduced and manganese, silicon, and nitrogen are all increased

M. C. Maguire; C. V. Robino; B. K. Damkroger; T. J. Lienert

1992-01-01

176

Manganese and Oxidative Damage in Cucumber  

Microsoft Academic Search

Micronutrients in low or high concentration can affect growth, respiration, photosynthesis, and reproduction in plants. Cucumber (Cucumis sativus, L.) is grown in India in areas low or high in manganese concentration in soils. A study was conducted to investigate the effects of manganese concentration on some metabolic activities affecting developmental responses in cucumber. Seed of cucumber, cv. Sonali, were grown

Rajeev Gopal

2008-01-01

177

Contaminant Transformation by a Biogenic Manganese Oxide  

NASA Astrophysics Data System (ADS)

Biomineralization of manganese by Pseudomonas putida strain MnB1 produces tetravalent manganese oxides that surround the exterior of the bacterial cell. The manganese oxides produced by P. putida transform the herbicide atrazine, a widespread environmental contaminant, by dechlorination, dealkylation and deamination reactions. The transformation reactions catalyzed by biogenic manganese oxide surfaces create a suite of transformation intermediates whose properties, such as aqueous solubility, toxicity and biodegradability, differ dramatically from those of the parent compound. The rates and products of atrazine transformation by biogenic manganese oxide surfaces were examined as functions of temperature and water potential. Air-dry samples of hydrous manganese oxide (? -MnO2) and biogenic manganese oxide were isopiestically equilibrated to -3.10, -0.50 and -0.04 MPa at 40 degrees Celsius and to -0.04 MPa at 20 and 30 degrees Celcius. The concentrations of atrazine and eight transformation intermediates were determined by HPLC. Our results suggest that biogenic manganese oxides may contribute greatly to the detoxification and immobilization of organic contaminants in the environment because of their nanoparticle size, large surface area and high chemical reactivity.

Toner, B. M.; Sposito, G.

2001-12-01

178

Manganese Neurotoxicity: An Update of Pathophysiologic Mechanisms  

Microsoft Academic Search

The central nervous system, and the basal ganglia in particular, is an important target in manganese neurotoxicity, a disorder producing neurological symptoms similar to that of Parkinson's disease. Increasing evidence suggests that astrocytes are a site of early dysfunction and damage; chronic exposure to manganese leads to selective dopaminergic dysfunction, neuronal loss, and gliosis in basal ganglia structures together with

Louise Normandin; Alan S. Hazell

2002-01-01

179

Manganese regulates expression of manganese peroxide by Phanerochaete chrysosporium  

SciTech Connect

The appearance of manganese peroxidase (MnP) activity in nitrogen-limited cultures of Phanerochaete chrysosporium is dependent on the presence of manganese. Cultures grown in the absence of Mn developed normally and produced normal levels of the secondary metabolite veratryl alcohol but produced no MnP activity. Immunoblot analysis indicated that appearance of MnP protein in the extracellular medium was also dependent on the presence of Mn. Intracellular MnP protein was detectable only in cells grown in the presence of Mn. MnP mRNA was detected by Northern (RNA) blot analysis only in cells grown in the presence of Mn. If Mn was added to 4-day-old nitrogen-limited Mn-deficient cultures, extracellular MnP activity appeared after 6 h and reached a maximum after 18 h. Both actinomycin D and cycloheximide inhibited the induction of MnP activity by Mn. These results indicate that Mn, the substrate of the enzyme, is involved in the transcriptional regulation of the MnP gene.

Brown, J.A.; Glenn, J.K.; Gold, M.H. (Oregon Graduate Institute of Science and Technology, Beaverton (USA))

1990-06-01

180

Radiation resistant austenitic stainless steel alloys  

Microsoft Academic Search

An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from

P. J. Maziasz; D. N. Braski; A. F. Rowcliffe

1987-01-01

181

Radiation resistant austenitic stainless steel alloys  

Microsoft Academic Search

An austenitic stainless steel alloy is disclosed, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4%

P. J. Maziasz; D. N. Braski; A. F. Rowcliffe

1989-01-01

182

Radiation resistant austenitic stainless steel alloys  

Microsoft Academic Search

An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from

Philip J. Maziasz; David N. Braski; Arthur F. Rowcliffe

1989-01-01

183

New Experimental Evidence on the Incomplete Transformation Phenomenon in Steel.  

SciTech Connect

The aim of this work is to analyse the carbon content distribution in austenite during isothermal bainite formation and the incomplete reaction phenomenon by means of X-ray diffraction analysis and atom-probe tomography in high silicon, manganese alloyed steels. Results provide new evidence on the explanation for the incomplete reaction phenomenon and the bainite transformation theory.

Caballero, Francesca G. [CENIM-CSIC, Madrid, Spain; Garcia-Mateo, C. [CENIM-CSIC, Madrid, Spain; Santofimia, M. J. [Delft University of Technology, Delft, Netherlands; Miller, Michael K [ORNL; Garcia de Andres, C [CENIM-CSIC, Madrid, Spain

2009-01-01

184

The Structural Stability of Manganese Oxide Electrodes for Lithium Batteries  

Microsoft Academic Search

Manganese oxides are of interest as insertion electrodes for rechargeable 3 V and 4 V lithium batteries. During discharge, lithium ions are inserted into the manganese oxide host structure with a concomitant reduction of the manganese ions; the reverse process occurs on charge. The cycle life of these batteries is critically dependent on the ability of the manganese oxide structure

Michael M. Thackeray

1997-01-01

185

Thermal conductivity of commercially available 21-6-9 stainless steel  

SciTech Connect

Thermal conductivity values of 21-6-9 stainless steel over the temperature range of 5 K to 120 K are reported. Thermal conductivity integrals are measured using a steady-state heat flux method. The resulting data are fit with a polynomial and differentiated to obtain the conductivity. The derived conductivity is compared to published data for high-manganese stainless steels and to data for other stainless steels. A discussion of the methodology and its accuracy is included.

Yuecel, A.; Maddocks, J.R.

1993-08-01

186

Design and testing of piezo motors for non-magnetic and/or fine positioning applications  

NASA Astrophysics Data System (ADS)

Piezoelectric motors offer several outstanding characteristics that may be very interesting for new scientific instruments in space applications. Piezo motors use a combination of electro-mechanical and frictional forces for generating a progressive motion; they are well suited for positioning applications because they exhibit a large force at rest without any power supply, and they often do not require any reduction gear. They are increasingly used in optical applications. Using piezo motors in space applications may become more and more relevant because of the continuous trend towards adaptive optics in future scientific payloads. In general, piezoelectric actuators are more and more used in space. Piezoelectric motors exhibit a number of advantages compared to conventional electromagnetic (stepping) motors, e.g. superior force/mass ratio, improved direct drive capability, no power supply to maintain a position, feasibility of a fully non-magnetic motor design. In this context, two complementary concepts have been designed and evaluated in the frame of ESA funded research and development activities: a resonant concept, called Rotary Piezo Actuator (RPA), a quasi-static concept, called Rotary Piezo Motor for High Precision Pointing (RPMHPP). The developed Rotary Piezo Actuator (RPA) is based on a Ultrasonic Piezo Drive (UPD) unit that drives a friction ring on the rotor part supported by a ball bearing assembly. This new motorization principle offers excellent motion dynamics and positioning accuracy combined with a high un-powered torque at standstill, and it does not rely on any magnetic features. A rotary piezo motor compliant with the requirements of a reference space application has been designed and tested. The technology remains challenging to be mastered, since the interdisciplinary aspects of the concept include, among others, drive electronics and controller design, piezo-electricity, contact mechanics and tribology. The conceptual design has lead to a cup configuration, in which the stator is placed in the inner diameter of a duplex ball bearing assembly. Despite the mass penalty of the rotor suspension, this configuration has been preferred for an easier wear debris confinement and higher support stiffness. Development testing examined two routes for the friction material (that should exhibit a low wear rate and a high friction coefficient, which should be similar in air and in vacuum): a polymer solution, already known and tested by CEDRAT TECHNOLOGIES, and a ceramic solution. Some potential applications have been identified both in the space sector (for instance magnetometer motorisation for the SWARM mission) and in other sectors, such as motorisation of equipment for Magnetic Resonant Imaging, taking benefit from the non-magnetic design option of the RPA. The second concept (RPMHPP) aims at providing very high pointing accuracy for future instruments such as the one foreseen for telescope pointing in the LISA constellation. In this concept, the piezo actuators operate in quasi-static mode and lead to a robust design, able to withstand a large non-operational temperature range (-140 to +140C). Although the concept could allow for a full rotation, the prototype was implemented with an elastic guiding of the shaft: the angular stroke is +/-1 and the measured angular positioning accuray is in the range of 100 nrad.

Six, M. F.; Le Letty, R.; Seiler, R.; Coste, P.

2005-07-01

187

Non-magnetic Iron Rich Microspherules from Younger Dryas Boundary Layer  

NASA Astrophysics Data System (ADS)

We report the discovery of abundance peaks of high-temperature non-magnetic spherules at 3 sites that date at or close to the onset of the Younger Dryas (YD) cooling episode at 12.9 0.1 kiloannum. Two sites (Gainey and Blackwater Draw) exhibit human cultural artifact sequences that rank them among the premier end-Pleistocene archeological locations. The third site has been discovered in southern part of Czech Republic within the sedimentary record of paleolake Svarcenberk. The spherules, sometimes associated with high temperature melt-glass, are found in the Younger Dryas boundary (YDB) layer proposed to have resulted from a cosmic impact/airburst (Firestone et al., 2007). That event was posited to have triggered Younger Dryas cooling, contributed to megafaunal extinctions, and led to human cultural shifts and population decreases across the Northern Hemisphere. Reports of peak abundances in YDB impact-related spherules have been confirmed by several independent groups, but disputed by several others. We have performed geochemical analyses with energy dispersive x-ray spectroscopy on YDB spherules, supported by examination of surface ultrastructures by scanning electron microscope. These analyses demonstrate that the spherules were not formed through volcanic, cosmic, anthropogenic, biogenic, or authigenic processes. Instead, they are comprised of high-temperature mineral phases of terrestrial source rocks and sediments. They are also geochemically similar to spherules, melted glass tektites, and impact ejecta recovered from twelve known impact craters and strewnfields, including the Australasian tektite field (780 kiloannum) and the Cretaceous-Paleogene impact layer (65 million years), supporting the hypothesis that they formed by cosmic impact. Magnetic analyses performed on spherules allowed separation of microspherules into two groups. Group A with enhanced coercivity corresponds to microspheres composed of nanosphere agglomerates with high silica content. Group B with low susceptibility corresponds to crystallized microspheres. Magnetic signature of both groups show that their genesis is not connected with lightning discharge and rather confirms magnetization in ambient geomagnetic field.

Kletetschka, G.; Nabelek, L.; Svitavska-Sokolova, H.; Kadlec, J.; Bunch, T. E.; West, A.; Firestone, R. B.

2013-05-01

188

Manganese metallurgy review. Part I: Leaching of ores\\/secondary materials and recovery of electrolytic\\/chemical manganese dioxide  

Microsoft Academic Search

The world rapidly growing demand for manganese has made it increasingly important to develop processes for economical recovery of manganese from low grade manganese ores and other secondary sources. Part I of this review outlines metallurgical processes for manganese production from various resources, particularly focusing on recent developments in direct hydrometallurgical leaching and recovery processes to identify potential sources of

Wensheng Zhang; Chu Yong Cheng

2007-01-01

189

Isotopic evidence for organic matter oxidation by manganese reduction in the formation of stratiform manganese carbonate ore  

Microsoft Academic Search

Unlike other marine-sedimentary manganese ore deposits, which are largely composed of manganese oxides, the primary ore at Molango (Hidalgo State, Mexico) is exclusively manganese carbonate (rhodochrosite, Mn-calcite, kutnahorite). Stable isotope studies of the carbonates from Molango provide critical new information relevant to the controversy over syngenetic and diagenetic models of stratiform manganese deposit formation. Negative 13 C values for carbonates

Patrick M. Okita; J. Barry Maynard; Elliott C. Spiker; Eric R. Force

1988-01-01

190

Nursing support, workload, and intent to stay in Magnet, Magnet-aspiring, and non-Magnet hospitals.  

PubMed

This study examined the differences between nurses' (N = 3,337) scores on organizational support, workload, satisfaction, and intent to stay between Magnet, Magnet-aspiring, and non-Magnet hospitals. The study was conducted using the Individual Workload Perception Scale, a valid and reliable tool with 32 Likert scale items, with nurses from 11 states, 15 institutions, and 292 diverse units. Results indicate that nurses at Magnet hospitals had significantly better scores on all subscales. Furthermore, nurses from Magnet-aspiring hospitals had better scores than did nurses from non-Magnet facilities. Conclusions of the study indicate that the Magnet program is meeting its intended goal: to provide a professional practice environment for staff nurses. Nurse executives may consider using the Individual Workload Perception Scale as a way to assess their organization's culture as it relates to professional practice of the registered nurse. PMID:17415107

Lacey, Susan R; Cox, Karen S; Lorfing, Kathleen C; Teasley, Susan L; Carroll, Cathryn A; Sexton, Kathy

2007-04-01

191

Regulation of Superoxide Dismutase Activity by Dietary Manganese1  

Microsoft Academic Search

The activity of Superoxide dismutase in rats, mice and chickens fed purified diets containing various levels of manganese has been studied. In liver of manganese-deficient mice, the activity of CNMnsensitive manganese Superoxide dismutase was only 17% of that found in control mice. In the brain, Superoxide dismutase activity was reduced by 50% in the manganese-deficient mice. In manganese-deficient rats, activity

GUGLIELMO DEROSA; CARL L. KEEN

2010-01-01

192

[Manganese in atherogenesis: detection, origin, and role].  

PubMed

The role of transition metal ions in atherogenesis is controversial; they can participate in the hydroxyl radical generation and catalyze the reactive oxygen species neutralization reaction as cofactors of antioxidant enzymes. Using EPR spectroscopy, we revealed that 70% of the samples of aorta with atherosclerotic lesions possessed superoxide dismutase activity, 100% of the samples initiated Fenton reaction and demonstrated the presence of manganese paramagnetic centers. The sodA gene encoding manganese-dependent bacterial superoxide dismutase was not found in the samples of atherosclerotic plaques by PCR using degenerate primers. The data obtained indicates the perspectives of manganese analysis as a marker element in the express diagnostics of atherosclerosis. PMID:22856134

Lozhkin, A P; Biktagirov, T B; Abdul'ianov, V A; Gorshkov, O V; Timonina, E V; Mamin, G V; Orlinski?, S B; Silkin, N I; Chernov, V M; Kha?rullin, R N; Salakhov, M Kh; Il'inskaia, O N

2012-01-01

193

Chronic manganese poisoning: A neuropathological study with determination of manganese distribution in the brain  

Microsoft Academic Search

An autopsy case of a 52-year-old man suffering from chronic manganese poisoning (CMP) is reported with determination of the manganese distribution in the brain. The patient had been working in a manganese ore crushing plant since 1965. In 1967 he began to complain of difficulties in walking and diminished libido. Later, he developed various neuro-psychiatric symptoms including euphoria, emotional incontinence,

M. Yamada; S. Ohno; I. Okayasu; R. Okeda; S. Hatakeyama; H. Watanabe; K. Ushio; H. Tsukagoshi

1986-01-01

194

Environmental assessment of the behavior of a BOF steel slag used in road construction : the PRECODD-ECLAIR  

E-print Network

(Ca2Fe2O5) and solid solutions containing iron and manganese oxides ((Fe, Mn,Mg,Ca)O) (Goldring, and the first results of the slag characterization. Keywords: Steel slag, civil engineering, chemical analysis the additions during ore reduction and from the refractory wall of the oven. Leaching tests carried out on steel

Paris-Sud XI, Université de

195

INFLUENCE OF BORON ON PRE AND POST IRRADIATION PROPERTIES OF TYPE 304 STAINLESS STEEL AND WELD METAL  

Microsoft Academic Search

Experimental heats of 2 wt% natural boron modified Type 304 stainless ; steel incorporating scrap from a commercial heat of the alloy, which failed to ; convert to sheet product, established the necessity of maintaining minimum ; manganese and silicon contents. When chemical composition is controlled, boron ; containing Type 304 stainless steels can be converted to sheet products which

N. Balai; L. C. Hymes

1960-01-01

196

21 CFR 184.1452 - Manganese gluconate.  

...by reacting manganese carbonate with gluconic acid in aqueous medium and then crystallizing the product. (b) The ingredient...accordance with section 412(g) of the Federal Food, Drug, and Cosmetic Act (the act) or with regulations promulgated under...

2014-04-01

197

21 CFR 184.1452 - Manganese gluconate.  

Code of Federal Regulations, 2012 CFR

...by reacting manganese carbonate with gluconic acid in aqueous medium and then crystallizing the product. (b) The ingredient...accordance with section 412(g) of the Federal Food, Drug, and Cosmetic Act (the act) or with regulations promulgated under...

2012-04-01

198

21 CFR 184.1452 - Manganese gluconate.  

Code of Federal Regulations, 2011 CFR

...by reacting manganese carbonate with gluconic acid in aqueous medium and then crystallizing the product. (b) The ingredient...accordance with section 412(g) of the Federal Food, Drug, and Cosmetic Act (the act) or with regulations promulgated under...

2011-04-01

199

21 CFR 184.1452 - Manganese gluconate.  

Code of Federal Regulations, 2013 CFR

...by reacting manganese carbonate with gluconic acid in aqueous medium and then crystallizing the product. (b) The ingredient...accordance with section 412(g) of the Federal Food, Drug, and Cosmetic Act (the act) or with regulations promulgated under...

2013-04-01

200

21 CFR 184.1452 - Manganese gluconate.  

Code of Federal Regulations, 2010 CFR

...by reacting manganese carbonate with gluconic acid in aqueous medium and then crystallizing the product. (b) The ingredient...accordance with section 412(g) of the Federal Food, Drug, and Cosmetic Act (the act) or with regulations promulgated under...

2010-04-01

201

21 CFR 184.1461 - Manganese sulfate.  

...manganese dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2 ) ore with solid ferrous sulfate and coal, followed by leaching and crystallization. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed....

2014-04-01

202

21 CFR 184.1461 - Manganese sulfate.  

Code of Federal Regulations, 2013 CFR

...manganese dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2 ) ore with solid ferrous sulfate and coal, followed by leaching and crystallization. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed....

2013-04-01

203

Hydrogen embrittlement of structural steels.  

SciTech Connect

Carbon-manganese steels are candidates for the structural materials in hydrogen gas pipelines, however it is well known that these steels are susceptible to hydrogen embrittlement. Decades of research and industrial experience have established that hydrogen embrittlement compromises the structural integrity of steel components. This experience has also helped identify the failure modes that can operate in hydrogen containment structures. As a result, there are tangible ideas for managing hydrogen embrittement in steels and quantifying safety margins for steel hydrogen containment structures. For example, fatigue crack growth aided by hydrogen embrittlement is a key failure mode for steel hydrogen containment structures subjected to pressure cycling. Applying appropriate structural integrity models coupled with measurement of relevant material properties allows quantification of safety margins against fatigue crack growth in hydrogen containment structures. Furthermore, application of these structural integrity models is aided by the development of micromechanics models, which provide important insights such as the hydrogen distribution near defects in steel structures. The principal objective of this project is to enable application of structural integrity models to steel hydrogen pipelines. The new American Society of Mechanical Engineers (ASME) B31.12 design code for hydrogen pipelines includes a fracture mechanics-based design option, which requires material property inputs such as the threshold for rapid cracking and fatigue crack growth rate under cyclic loading. Thus, one focus of this project is to measure the rapid-cracking thresholds and fatigue crack growth rates of line pipe steels in high-pressure hydrogen gas. These properties must be measured for the base materials but more importantly for the welds, which are likely to be most vulnerable to hydrogen embrittlement. The measured properties can be evaluated by predicting the performance of the pipeline using a relevant structural integrity model, such as that in ASME B31.12. A second objective of this project is to enable development of micromechanics models of hydrogen embrittlement in pipeline steels. The focus of this effort is to establish physical models of hydrogen embrittlement in line pipe steels using evidence from analytical techniques such as electron microscopy. These physical models then serve as the framework for developing sophisticated finite-element models, which can provide quantitative insight into the micromechanical state near defects. Understanding the micromechanics of defects can ensure that structural integrity models are applied accurately and conservatively.

Somerday, Brian P.

2010-06-01

204

Electrochemical lithium intercalation in nanosized manganese oxides  

Microsoft Academic Search

X-ray amorphous manganese oxides were prepared by reduction of sodium permanganate by lithium iodide in aqueous medium (MnOx-I) and by decomposition of manganese carbonate at moderate temperature (MnOx-C). TEM showed that these materials are not amorphous, but nanostructured, with a prominent spinel substructure in MnOx-C. These materials intercalate lithium with capacities up to 200mAh\\/g at first cycle (potential window 1.84.3V)

Pierre Strobel; Cline Darie; F. Thiry; A. Ibarra-Palos; Maria Bacia; Olivier Proux; Jean-Bruno Soupart

2006-01-01

205

Manganese induced modifications in yttria stabilized zirconia  

NASA Astrophysics Data System (ADS)

We have investigated the role of manganese oxide on the crystallographic and morphological modifications of cubic 8 mol. % yttria stabilized zirconia (YSZ). X-ray diffraction studies indicate that manganese dissolution leads to partial transformation of cubic YSZ into the tetragonal polymorph along with contraction of the unit cell. Evolution of an undulated surface with 2-15 nm roughness has been observed using electron and atomic force microscopies.

Mahapatra, Manoj K.; Singh, Prabhakar; Misture, Scott T.

2012-09-01

206

Toenail, Blood and Urine as Biomarkers of Manganese Exposure  

PubMed Central

Objective This study examined the correlation between manganese exposure and manganese concentrations in different biomarkers. Methods Air measurement data and work histories were used to determine manganese exposure over a workshift and cumulative exposure. Toenail samples (n=49), as well as blood and urine before (n=27) and after (urine, n=26; blood, n=24) a workshift were collected. Results Toenail manganese, adjusted for age and dietary manganese, was significantly correlated with cumulative exposure in months 7-9, 10-12, and 7-12 before toenail clipping date, but not months 1-6. Manganese exposure over a work shift was not correlated with changes in blood nor urine manganese. Conclusions Toenails appeared to be a valid measure of cumulative manganese exposure 7 to 12 months earlier. Neither change in blood nor urine manganese appeared to be suitable indicators of exposure over a typical workshift. PMID:21494156

Laohaudomchok, Wisanti; Lin, Xihong; Herrick, Robert F.; Fang, Shona C.; Cavallari, Jennifer M.; Christiani, David C.; Weisskopf, Marc G.

2011-01-01

207

Pathophysiology of manganese-associated neurotoxicity.  

PubMed

Manganese (Mn) is a well established neurotoxin associated with specific damage to the basal ganglia in humans. The phenotype associated with Mn neurotoxicity was first described in two workers with occupational exposure to Mn oxide (Couper, 1837). Although the description did not use modern clinical terminology, a parkinsonian illness characterized by slowness of movement (bradykinesia), masked facies, and gait impairment (postural instability) appears to have predominated. Nearly 100 years later an outbreak of an atypical parkinsonian illness in a Chilean Mn mine provided a phenotypic description of a fulminant neurologic disorder with parkinsonism, dystonia, and neuropsychiatric symptoms (Rodier, 1955). Exposures associated with this syndrome were massive and an order of magnitude greater than modern exposures (Rodier, 1955; Hobson et al., 2011). The clinical syndrome associated with Mn neurotoxicity has been called manganism. Modern exposures to Mn occur primarily through occupations in the steel industry and welding. These exposures are often chronic and varied, occurring over decades in the healthy workforce. Although the severe neurologic disorder described by Rodier and Couper are no longer seen, several reports have suggested a possible increased risk of neurotoxicity in these workers (Racette et al., 2005b; Bowler et al., 2007; Harris et al., 2011). Based upon limited prior imaging and pathologic investigations into the pathophysiology of neurotoxicity in Mn exposed workers (Huang et al., 2003), many investigators have concluded that the syndrome spares the dopamine system distinguishing manganism from Parkinson disease (PD), the most common cause of parkinsonism in the general population, and a disease with characteristic degenerative changes in the dopaminergic system (Jankovic, 2005). The purpose of this symposium was to highlight recent advances in the understanding of the pathophysiology of Mn associated neurotoxicity from Caenorhabditis elegans to humans. Dr. Aschner's presentation discussed mechanisms of dopaminergic neuronal toxicity in C. elegans and demonstrates a compelling potential role of Mn in dopaminergic degeneration. Dr. Guilarte's experimental, non-human primate model of Mn neurotoxicity suggests that Mn decreases dopamine release in the brain without loss of neuronal integrity markers, including dopamine. Dr. Racette's presentation demonstrates a unique pattern of dopaminergic dysfunction in active welders with chronic exposure to Mn containing welding fumes. Finally, Dr. Dydak presented novel magnetic resonance (MR) spectroscopy data in Mn exposed smelter workers and demonstrated abnormalities in the thalamus and frontal cortex for those workers. This symposium provided some converging evidence of the potential neurotoxic impact of Mn on the dopaminergic system and challenged existing paradigms on the pathophysiology of Mn in the central nervous system. PMID:22202748

Racette, Brad A; Aschner, Michael; Guilarte, Tomas R; Dydak, Ulrike; Criswell, Susan R; Zheng, Wei

2012-08-01

208

The Structure and Properties of Plasma Sprayed Iron Oxide Doped Manganese Cobalt Oxide Spinel Coatings for SOFC Metallic Interconnectors  

Microsoft Academic Search

Manganese cobalt oxide spinel doped with Fe2O3 was studied as a protective coating on ferritic stainless steel interconnects. Chromium alloying causes problems at high\\u000a operation temperatures in such oxidizing conditions where chromium compounds evaporate and poison the cathode active area,\\u000a causing the degradation of the solid oxide fuel cell. In order to prevent chromium evaporation, these interconnectors need\\u000a a protective

Jouni Puranen; Juha Lagerbom; Leo Hyvrinen; Mikko Kylmlahti; Olli Himanen; Mikko Pihlatie; Jari Kiviaho; Petri Vuoristo

2011-01-01

209

Biogeochemical cycling of manganese in Oneida Lake, New York: whole lake studies of manganese  

NASA Technical Reports Server (NTRS)

Oneida Lake, New York is a eutrophic freshwater lake known for its abundant manganese nodules and a dynamic manganese cycle. Temporal and spatial distribution of soluble and particulate manganese in the water column of the lake were analyzed over a 3-year period and correlated with other variables such as oxygen, pH, and temperature. Only data from 1988 are shown. Manganese is removed from the water column in the spring via conversion to particulate form and deposited in the bottom sediments. This removal is due to biological factors, as the lake Eh/pH conditions alone can not account for the oxidation of the soluble manganese Mn(II). During the summer months the manganese from microbial reduction moves from the sediments to the water column. In periods of stratification the soluble Mn(II) builds up to concentrations of 20 micromoles or more in the bottom waters. When mixing occurs, the soluble Mn(II) is rapidly removed via oxidation. This cycle occurs more than once during the summer, with each manganese atom probably being used several times for the oxidation of organic carbon. At the end of the fall, whole lake concentrations of manganese stabilize, and remain at about 1 micromole until the following summer, when the cycle begins again. Inputs and outflows from the lake indicate that the active Mn cycle is primarily internal, with a small accumulation each year into ferromanganese nodules located in the oxic zones of the lake.

Aguilar, C.; Nealson, K. H.

1998-01-01

210

Effect of Carbon Dioxide on Availability of Manganese in Soil Producing Manganese Deficiency  

Microsoft Academic Search

A SERIES of experiments, extending over several years, in which potato plants were grown both in pots and in the field, in soil producing manganese deficiency, from the recently drained lake-bed at East Mailing Research Station, has led us to suspect the presence of some hitherto unexplained factor influencing manganese availability. The soil in question is an alluvial deposit containing

B. D. Bolas; G. B. Portsmouth

1948-01-01

211

Deposition of manganese sulfide and cadmium doped manganese sulfide thin films by M-CBD  

NASA Astrophysics Data System (ADS)

Un-doped and cadmium doped manganese sulfide thin films were prepared by M-CBD of aqueous solution onto glass substrates. The structural properties studied using X-ray diffraction showed that the un-doped manganese sulfide films exhibit amorphous structure; however Cd doped manganese sulfide films were crystalline. The surface morphological studies from SEM depicted the formation of clusters-like structure of un-doped manganese sulfide while the Cd doped film showed the nanocrystalline grains on the surface. From the optical studies, the absorbance in the wavelength range of 350-850 nm was found to increase after doping of Cd. The optical band gap was found to be 3.9 eV for un-doped manganese sulfide film and 3.7 eV for Cd doped films.

Pathan, Habib M.; Kale, Sampat S.; Pandit, Vishal K.

2012-06-01

212

Investigation of non-magnetic alloys for the suppression of tritium permeation. Final report  

SciTech Connect

This report describes a small (300 man hour) literature survey relating to the suppression of tritium loss by permeation through the walls of fusion reactors. The program was based on prior in-house Thermacore work to suppress hydrogen permeation into high temperature (800/sup 0/C) heat pipes. The Thermacore approach involves selection of a steel with a small (.5 to 5%) aluminum content. The aluminum is diffused to the surface and oxidized. The present work was aimed at identification of alloys which might combine low tritium permeation with other properties desired in fusion reactor vessels, heat exchangers, lithium-handling plumbing and other components likely to contain tritium. These properties include low radiation damage, low magnetic permeability, high temperature strength, and compatibility with potential heat transfer and blanket materials. The work consisted of two tasks: Problem Definition and Literature Search and Analysis.

None

1980-07-01

213

Cardiovascular Toxicities Upon Manganese Exposure  

PubMed Central

Manganese (Mn)-induced Parkinsonism has been well documented; however, little attention has been devoted to Mn-induced cardiovascular dysfunction. This review summarizes literature data from both animal and human studies on Mns effect on cardiovascular function. Clinical and epidemiological evidence suggests that the incidence of abnormal electrocardiogram (ECG) is significantly higher in Mn-exposed workers than that in the control subjects. The main types of abnormal ECG include sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinister megacardia, and ST-T changes. The accelerated heartbeat and shortened P-R interval appear to be more prominent in female exposed workers than in their male counterparts. Mn-exposed workers display a mean diastolic blood pressure that is significantly lower than that of the control subjects, especially in the young and female exposed workers. Animal studies indicate that Mn is capable of quickly accumulating in heart tissue, resulting in acute or sub-acute cardiovascular disorders, such as acute cardiodepression and hypotension. These toxic outcomes appear to be associated with Mn-induced mitochondrial damage and interaction with the calcium channel in the cardiovascular system. PMID:16382172

Jiang, Yueming; Zheng, Wei

2014-01-01

214

Manganese in dwarf spheroidal galaxies  

E-print Network

We provide manganese abundances (corrected for the effect of the hyperfine structure) for a large number of stars in the dwarf spheroidal galaxies Sculptor and Fornax, and for a smaller number in the Carina and Sextans dSph galaxies. Abundances had already been determined for a number of other elements in these galaxies, including alpha and iron-peak ones, which allowed us to build [Mn/Fe] and [Mn/alpha] versus [Fe/H] diagrams. The Mn abundances imply sub-solar [Mn/Fe] ratios for the stars in all four galaxies examined. In Sculptor, [Mn/Fe] stays roughly constant between [Fe/H]\\sim -1.8 and -1.4 and decreases at higher iron abundance. In Fornax, [Mn/Fe] does not vary in any significant way with [Fe/H]. The relation between [Mn/alpha] and [Fe/H] for the dSph galaxies is clearly systematically offset from that for the Milky Way, which reflects the different star formation histories of the respective galaxies. The [Mn/alpha] behavior can be interpreted as a result of the metal-dependent Mn yields of type II and ...

North, P; Jablonka, P; Hill, V; Shetrone, M; Letarte, B; Lemasle, B; Venn, K A; Battaglia, G; Tolstoy, E; Irwin, M J; Primas, F; Francois, P

2012-01-01

215

Determination of Plutonium-Beryllium Source Strength by Manganese Activation.  

National Technical Information Service (NTIS)

In this study the manganese-sulfate-bath technique was used to determine the total neutron output of a Plutonium-Beryllium neutron source. Activation trials were conducted using 4 different concentrations of manganese sulfate and 3 different size containe...

P. F. Whitworth

1988-01-01

216

High-Performance Manganese Oxide Catalysts for CO Oxidation  

Microsoft Academic Search

The catalytic activity of manganese dioxide samples in oxidation of CO and decomposition of hydrogen peroxide was studied. The promise of manganese dioxide obtained from fluorine-containing electrolytes as a catalyst for carbon monoxide oxidation was considered.

N. D. Ivanova; S. V. Ivanov; E. I. Boldyrev; G. V. Sokol'skii; I. S. Makeeva

2002-01-01

217

Efficiency analysis for a manganese-oxide-based thermochemical cycle  

Microsoft Academic Search

A thermochemical cycle for the solar production of hydrogen is proposed. The cycle includes: (1) the conversion of solar to chemical energy by the thermal reduction of manganese(III) oxide to manganese(II) oxide at temperatures below 1900K, (2) the production of hydrogen by reacting manganese(II) oxide with sodium hydroxide, and (3) the separation of manganese oxide from sodium hydroxide by a

M Sturzenegger; P Nesch

1999-01-01

218

Nervous system effects of occupational manganese exposure on South African manganese mineworkers.  

PubMed

Occupational exposure to airborne manganese dust has been shown to produce adverse effects on the central nervous system. Four hundred and eighty-nine blue and white collar manganese mineworkers from South Africa were studied cross-sectionally to investigate the nervous system effects of medium to low occupational manganese exposures. The different facilities included underground mines, surface processing plants, and office locations. A job exposure matrix was constructed using routine occupational hygiene data. Exposure variables included years of service, a cumulative exposure index (CEI) and average intensity of exposure (AINT) across all jobs, and blood manganese. Endpoints included items from the Q16, WHO-NCTB, SPES, and Luria-Nebraska test batteries, and a brief clinical examination. Potential confounders and effect modifiers included age, level of education, past medical history including previous head injury, previous neurotoxic job exposures, tobacco use, alcohol use and home language. Associations were evaluated by multiple linear and logistic regression modeling. Average exposure intensity across all jobs was 0.21mg/m(3) manganese dust. Multivariate analyses showed that none of the symptom nor test results were associated with any measure of exposure including blood manganese, after adjustment for confounders. This relatively large null study indicates that manganese miners exposed on average across all jobs to MnO(2) at levels near the American Conference of Governmental Industrial Hygienists Threshold Limit Value (ACGIH TLV) are unlikely to have a subclinical neurotoxicity problem. PMID:12900078

Myers, Jonathan E; teWaterNaude, Jim; Fourie, Markus; Zogoe, H B Abie; Naik, Inakshi; Theodorou, Penny; Tassel, Halina; Daya, Aarti; Thompson, Mary Lou

2003-08-01

219

Component masses of young, wide, non-magnetic white dwarf binaries in the Sloan Digital Sky Survey Data Release 7  

NASA Astrophysics Data System (ADS)

We present a spectroscopic component analysis of 18 candidate young, wide, non-magnetic, double-degenerate binaries identified from a search of the Sloan Digital Sky Survey Data Release 7 (DR7). All but two pairings are likely to be physical systems. We show SDSS J084952.47+471247.7 + SDSS J084952.87+471249.4 to be a wide DA + DB binary, only the second identified to date. Combining our measurements for the components of 16 new binaries with results for three similar, previously known systems within the DR7, we have constructed a mass distribution for the largest sample to date (38) of white dwarfs in young, wide, non-magnetic, double-degenerate pairings. This is broadly similar in form to that of the isolated field population with a substantial peak around M 0.6 M?. We identify an excess of ultramassive white dwarfs and attribute this to the primordial separation distribution of their progenitor systems peaking at relatively larger values and the greater expansion of their binary orbits during the final stages of stellar evolution. We exploit this mass distribution to probe the origins of unusual types of degenerates, confirming a mild preference for the progenitor systems of high-field-magnetic white dwarfs, at least within these binaries, to be associated with early-type stars. Additionally, we consider the 19 systems in the context of the stellar initial mass-final mass relation. None appear to be strongly discordant with current understanding of this relationship.

Baxter, R. B.; Dobbie, P. D.; Parker, Q. A.; Casewell, S. L.; Lodieu, N.; Burleigh, M. R.; Lawrie, K. A.; Klebi, B.; Koester, D.; Holland, B. R.

2014-06-01

220

Manganese (II) induces chemical hypoxia by inhibiting HIF-prolyl hydroxylase: Implication in manganese-induced pulmonary inflammation  

SciTech Connect

Manganese (II), a transition metal, causes pulmonary inflammation upon environmental or occupational inhalation in excess. We investigated a potential molecular mechanism underlying manganese-induced pulmonary inflammation. Manganese (II) delayed HIF-1{alpha} protein disappearance, which occurred by inhibiting HIF-prolyl hydroxylase (HPH), the key enzyme for HIF-1{alpha} hydroxylation and subsequent von Hippel-Lindau(VHL)-dependent HIF-1{alpha} degradation. HPH inhibition by manganese (II) was neutralized significantly by elevated dose of iron. Consistent with this, the induction of cellular HIF-1{alpha} protein by manganese (II) was abolished by pretreatment with iron. Manganese (II) induced the HIF-1 target gene involved in pulmonary inflammation, vascular endothelial growth factor (VEGF), in lung carcinoma cell lines. The induction of VEGF was dependent on HIF-1. Manganese-induced VEGF promoted tube formation of HUVEC. Taken together, these data suggest that HIF-1 may be a potential mediator of manganese-induced pulmonary inflammation.

Han, Jeongoh [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of); Lee, Jong-Suk [Laboratory of Physiology, College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Choi, Daekyu; Lee, Youna; Hong, Sungchae; Choi, Jungyun; Han, Songyi [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of); Ko, Yujin; Kim, Jung-Ae [Laboratory of Physiology, College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Mi Kim, Young [Medicinal Chemistry, College of Pharmacy, Pusan National University, Busan (Korea, Republic of); Jung, Yunjin [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of)], E-mail: jungy@pusan.ac.kr

2009-03-15

221

Essentiality, Toxicity, and Uncertainty in the Risk Assessment of Manganese  

Microsoft Academic Search

Risk assessments of manganese by inhalation or oral routes of exposure typically acknowledge the duality of manganese as an essential element at low doses and a toxic metal at high doses. Previously, however, risk assessors were unable to describe manganese pharmacokinetics quantitatively across dose levels and routes of exposure, to account for mass balance, and to incorporate this information into

William K. Boyes

2010-01-01

222

Brain manganese accumulation following systemic administration of different forms  

Microsoft Academic Search

The content and retention of manganese in the blood and brain of mice exposed to different forms of the metal was compared. Mice received an acute sc injection of manganese as the chloride or oxide (Mn3O4) or as the organic MMT. A single injection markedly elevated brain manganese concentrations within 1 day and elevated levels were maintained for at least

Gerald Gianutsos I; Michael D. Seltzer; Riyad Saymeh; Man-Li Wang Wu; R. G. Michel

1985-01-01

223

EFFECT OF MANGANESE ON GROI,IIHOF SPHAEROTILUS  

E-print Network

l-rrE I TLg EFFECT OF MANGANESE ON GROI,IIHOF SPHAEROTILUS DISCOPHORUS THESIS SUB spontaneously oxidize at physiological pH' whereas manganous manganese does not, the latter has been preferred ln modern studies of the problem. Work by Prav6 (f4) suggested that manganese autotrophy night exist

Luther, Douglas S.

224

Pwave Pairing and Colossal Magnetoresistance in Manganese Oxides  

E-print Network

P­wave Pairing and Colossal Magnetoresistance in Manganese Oxides Yong­Jihn Kim y Department that the existing experimental data of most manganese ox­ ides show the frustrated p­wave superconducting paid to the manganese oxides since the observa­ tion of colossal magnetoresistance (CMR). 1\\Gamma4

225

Original Research Manganese-Enhanced MRI Reveals Multiple  

E-print Network

Original Research Manganese-Enhanced MRI Reveals Multiple Cellular and Vascular Layers in Normal,6* Purpose: To use manganese-enhanced magnetic reso- nance imaging (MEMRI) at 25 ? 25 ? 800 mm3 to image different retinal and vascular layers in the rat retinas. Materials and Methods: Manganese

Duong, Timothy Q.

226

Terrestrial manganese-53 --A new monitor of Earth surface processes  

E-print Network

Terrestrial manganese-53 -- A new monitor of Earth surface processes Joerg M. Schaefer a,, Thomas of the terrestrial cosmogenic radionuclide manganese-53 (T1/2 =3.7 Ma) measured in thirteen samples from nine dolerite surfaces in the Dry Valleys, Antarctica. The terrestrial manganese-53 concentrations correlate

Winckler, Gisela

227

Growth of Manganese Oxide Nanostructures Alters the Layout of  

E-print Network

Growth of Manganese Oxide Nanostructures Alters the Layout of Adhesion on a Carbonate Substrate C H-volume microscopy and a silicon-nitride probe, we measure changes in adhesion when a patchy overgrowth of manganese for advancingthemechanisticmodelingofthefateandtransport of environmental contaminants (11, 12). Manganese oxide (MnOx) nanostructures grown

228

Manganese in dwarf spheroidal galaxies  

NASA Astrophysics Data System (ADS)

We provide manganese abundances (corrected for the effect of the hyperfine structure) for a large number of stars in the dwarf spheroidal galaxies Sculptor and Fornax, and for a smaller number in the Carina and Sextans dSph galaxies. Abundances had already been determined for a number of other elements in these galaxies, including ? and iron-peak ones, which allowed us to build [Mn/Fe] and [Mn/?] versus [Fe/H] diagrams. The Mn abundances imply sub-solar [Mn/Fe] ratios for the stars in all four galaxies examined. In Sculptor, [Mn/Fe] stays roughly constant between [Fe/H] ~ -1.8 and -1.4 and decreases at higher iron abundance. In Fornax, [Mn/Fe] does not vary in any significant way with [Fe/H]. The relation between [Mn/?] and [Fe/H] for the dSph galaxies is clearly systematically offset from that for the Milky Way, which reflects the different star formation histories of the respective galaxies. The [Mn/?] behavior can be interpreted as a result of the metal-dependent Mn yields of Type II and Type Ia supernovae. We also computed chemical evolution models for star formation histories matching those determined empirically for Sculptor, Fornax, and Carina, and for the Mn yields of SNe Ia, which were assumed to be either constant or variable with metallicity. The observed [Mn/Fe] versus [Fe/H] relation in Sculptor, Fornax, and Carina can be reproduced only by the chemical evolution models that include a metallicity-dependent Mn yield from the SNe Ia. Based on observations made with the FLAMES-GIRAFFE multi-object spectrograph mounted on the Kuyen VLT telescope at ESO-Paranal Observatory (programs 171.B-0588, 074.B-0415 and 076.B-0146).Appendices are available in electronic form at http://www.aanda.org

North, P.; Cescutti, G.; Jablonka, P.; Hill, V.; Shetrone, M.; Letarte, B.; Lemasle, B.; Venn, K. A.; Battaglia, G.; Tolstoy, E.; Irwin, M. J.; Primas, F.; Franois, P.

2012-05-01

229

Comparative toxicokinetics of manganese chloride and methylcyclopentadienyl manganese tricarbonyl (MMT) in Sprague-Dawley rats.  

PubMed

The toxicokinetics of manganese (Mn) was investigated in male and female rats either following a single intravenous (iv) or oral dose of MnCl2 (6.0 mg Mn/kg), or following a single oral dose of methylcyclopentadienyl manganese tricarbonyl (MMT) (20 mg MMT/kg or 5.6 mg Mn/kg). The plasma concentrations of manganese were quantified by atomic absorption spectrophotometry (AAS). Upon iv administration of MnCl2, manganese rapidly disappeared from blood with a terminal elimination t1/2 of 1.83 h and CL8 of 0.43 L/h/kg. The plasma concentration-time profiles of manganese could be described by C = 41.9e(-424t) + 2.1e(-0.44t). Following oral administration of MnCl2, manganese rapidly entered the systemic circulation (Tmax = 0.25 h). The absolute oral bioavailability was about 13%. Oral dose of MMT resulted in a delayed Tmax(7.6 h), elevated Cmax (0.93 microg/ml), and prolonged terminal t1/2 (55.1 h). The rats receiving MMT had an apparent clearance (CL/F = 0.09 L/h x kg) about 37-fold less than did those who were dosed with MnCl2. Accordingly, the area under the plasma concentration-time curves (AUC) of manganese in MMT-treated rats was about 37-fold greater than that in MnCl2-treated rats. A gender-dependent difference in toxicokinetic profiles of plasma manganese was also observed. Female rats displayed a greater AUC than that of male rats. Although the apparent volume of distribution of manganese was similar in both sexes, the apparent clearance in males was about twice that observed in females. The results indicated that after oral administration, the MMT-derived manganese displayed higher and more prolonged plasma concentration-time profiles than MnCl2-derived manganese. Thus, MMT-derived manganese appeared likely to accumulate in the body following repeated exposure. PMID:10774811

Zheng, W; Kim, H; Zhao, Q

2000-04-01

230

Bacterial manganese reduction and growth with manganese oxide as the sole electron acceptor  

NASA Technical Reports Server (NTRS)

Microbes that couple growth to the reduction of manganese could play an important role in the biogeochemistry of certain anaerobic environments. Such a bacterium, Alteromonas putrefaciens MR-1, couples its growth to the reduction of manganese oxides only under anaerobic conditions. The characteristics of this reduction are consistent with a biological, and not an indirect chemical, reduction of manganese, which suggest that this bacterium uses manganic oxide as a terminal electron acceptor. It can also utilize a large number of other compounds as terminal electron acceptors; this versatility could provide a distinct advantage in environments where electron-acceptor concentrations may vary.

Myers, Charles R.; Nealson, Kenneth H.

1988-01-01

231

Isotopic evidence for organic matter oxidation by manganese reduction in the formation of stratiform manganese carbonate ore  

Microsoft Academic Search

Unlike other marine-sedimentary manganese ore deposits, which are largely composed of manganese oxides, the primary ore at Molango (Hidalgo State, Mexico) is exclusively manganese carbonate (rhodochrosite, Mn-calcite, kutnahorite). Stable isotope studies of the carbonates from Molango provide critical new information relevant to the controversy over syngenetic and diagenetic models of stratiform manganese deposit formation. Negative δ¹³C values for carbonates from

P. M. Okita; J. B. Maynard; E. C. Spiker; E. R. Force

1988-01-01

232

Manganese Distribution in the Brain and Neurobehavioral Changes Following Inhalation Exposure of Rats to Three Chemical Forms of Manganese  

Microsoft Academic Search

The central nervous system is an important target for manganese (Mn) intoxication in humans; it may cause neurological symptoms similar to Parkinsons disease. Manganese compounds emitted from the tailpipe of vehicles using methylcyclopentadienyl manganese tricarbonyl (MMT) are primarily Mn phosphate, Mn sulfate, and Mn phosphate\\/sulfate mixture. The purpose of this study is to compare the patterns of Mn distribution in

Louise Normandin; Linda Ann Beaupr; Fariba Salehi; Annie St.-Pierre; Greg Kennedy; Donna Mergler; Roger F Butterworth; Suzanne Philippe; Joseph Zayed

2004-01-01

233

Electron Energy-Loss Safe-Dose Limits for Manganese Valence Measurements in Environmentally Relevant Manganese Oxides  

E-print Network

Electron Energy-Loss Safe-Dose Limits for Manganese Valence Measurements in Environmentally Relevant Manganese Oxides Kenneth J. T. Livi,*, Brandon Lafferty,,§ Mengqiang Zhu,,# Shouliang Zhang, Anne Houssiniere, BP 32229, 44322 Nantes Cedex 3, France *S Supporting Information ABSTRACT: Manganese (Mn) oxides

Sparks, Donald L.

234

Processing of Long-Length YBCO Coated Conductors Based on Stainless Steel Tapes  

Microsoft Academic Search

Recent progress is reported in the development of long lengths (up to 100 m) of YBCO coated conductors with good mechanical stability and improved critical current homogeneity. A non-magnetic CrNi stainless steel tape, 0.1 mm thick, is employed as a substrate tape. Prior to deposition, the tape is coated with yttria stabilized zirconia in the form of a bi-axially textured

A.. Usoskin; L.. Kirchhoff; J.. Knoke; B.. Prause; A.. Rutt; V.. Selskij; D. E. Farrell

2007-01-01

235

NANO-FINISHING OF STAINLESS-STEEL TUBES USING ROTATIONAL MAGNETORHEOLOGICAL ABRASIVE FLOW FINISHING PROCESS  

Microsoft Academic Search

A new polishing method called Rotational (R)-Magnetorheological Abrasive Flow Finishing (MRAFF) process has been proposed by rotating a magnetic field applied to the Magnetorheological polishing (MRP) medium in addition to the reciprocating motion provided by the hydraulic unit to finish internal surface of cylindrical stainless steel (non-magnetic) workpiece. By intelligently controlling these two motions uniform smooth mirror-like finished surface in

Manas Das; V. K. Jain; P. S. Ghoshdastidar

2010-01-01

236

Manganese Cell Labeling of Murine Hepatocytes Using Manganese(III)-Transferrin  

PubMed Central

Manganese(III)-transferrin (Mn(III)-Tf) was investigated as a way to accomplish manganese-labeling of murine hepatocytes for MRI contrast. It is postulated that Mn(III)-Tf can exploit the same transferrin-receptor-dependent and -independent metabolic pathways used by hepatocytes to transport the iron analogue Fe(III)-Tf. More specifically, it was investigated whether manganese delivered by transferrin could give MRI contrast in hepatocytes. Comparison of the T1 and T2 relaxation times of Mn(III)-Tf and Fe(III)-Tf over the same concentration range showed that the r1 relaxivities of the two metalloproteins are the same in vitro; with little contribution from paramagnetic enhancement. The degree of manganese cell labeling following incubation for 27 h in 31.5 ?M Mn(III)-Tf was comparable to that of hepatocytes incubated in 500 ?M Mn2+ for 1 h. The intrinsic manganese tissue relaxivity between Mn(III)-Tf-labeled and Mn2+-labeled cells was found to be the same; consistent with Mn(III) being released from transferrin and reduced to Mn2+. For both treatment regimens, manganese uptake by hepatocytes appeared to saturate in the first 12 h of the incubation period and may explain why the efficiency of hepatocyte cell labeling by the two methods appeared to be comparable in spite of the ~16-fold difference in effective manganese concentration. Hepatocytes continuously released manganese, as detected by MRI, and this was the same for both Mn2+- and Mn(III)-Tf-labeled cells. Manganese release may be the result of normal hepatocyte function; much in the same way that hepatocytes excrete manganese into the bile in vivo. This approach exploits a biological process namely receptor binding, endocytosis, and endosomal acidification to initiate the release of an MRI contrast agent; potentially confering more specificity to the labeling process. The ubiquitous expression of transferrin receptors by eukaryotic cells should make Mn(III)-Tf particularly useful for manganese labeling of a wide variety of cells both in culture and in vivo. PMID:18546093

Sotak, Christopher H.; Sharer, Kathryn; Koretsky, Alan P.

2011-01-01

237

Microstructural characterization of irradiated PWR steels using the atom probe field-ion microscope  

SciTech Connect

Atom probe field-ion microscopy has been used to characterize the microstructure of a neutron-irradiated A533B pressure vessel steel weld. The atomic spatial resolution of this technique permits a complete structural and chemical description of the ultra-fine features that control the mechanical properties to be made. A variety of fine scale features including roughly spherical copper precipitates and clusters, spherical and rod-shaped molybdenum carbide and disc-shaped molybdenum nitride precipitates were observed to be inhomogeneously distributed in the ferrite. The copper content of the ferrite was substantially reduced from the nominal level. A thin film of molybdenum carbides and nitrides was observed on grain boundaries in addition to a coarse copper-manganese precipitate. Substantial enrichment of manganese and nickel were detected at the copper-manganese precipitate-ferrite interface and this enrichment extended into the ferrite. Enrichment of nickel, manganese and phosphorus were also measured at grain boundaries.

Miller, M.K.; Burke, M.G.

1987-08-01

238

Comparative Toxicokinetics of Manganese Chloride and Methylcyclopentadienyl Manganese Tricarbonyl (MMT) in Sprague-Dawley Rats  

Microsoft Academic Search

The toxicokinetics of manganese (Mn) was investigated in male and female rats either following a single intravenous (iv) or oral dose of MnCl2 (6.0 mg Mn\\/kg), or following a single oral dose of methylcyclopentadienyl manganese tricarbonyl (MMT) (20 mg MMT\\/kg or 5.6 mg Mn\\/kg). The plasma concentrations of man- ganese were quantified by atomic absorption spectrophotometry (AAS). Upon iv administration

Wei Zheng; Hyaehwan Kim; Qiuqu Zhao

2000-01-01

239

Embrittlement of RPV steels: An atom probe tomography perspective  

NASA Astrophysics Data System (ADS)

Atom probe tomography has played a key role in the understanding of the embrittlement of neutron irradiated reactor pressure vessel steels through the atomic level characterization of the microstructure. Atom probe tomography has been used to demonstrate the importance of the post weld stress relief treatment in reducing the matrix copper content in high copper alloys, the formation of 2-nm-diameter copper-, nickel-, manganese- and silicon-enriched precipitates during neutron irradiation in copper containing RPV steels, and the coarsening of these precipitates during post irradiation heat treatments. Atom probe tomography has been used to detect 2-nm-diameter nickel-, silicon- and manganese-enriched clusters in neutron irradiated low copper and copper free alloys. Atom probe tomography has also been used to quantify solute segregation to, and precipitation on, dislocations and grain boundaries.

Miller, M. K.; Russell, K. F.

2007-09-01

240

Particulate Manganese in the Black Sea.  

National Technical Information Service (NTIS)

Manganese nodules are thought to form by the oxidation of Mn(II) to Mn(IV) at an active site, and the trace metal enrichments have been related to the surface chemistry of this oxidized product. Recent data from the Black Sea have shown the existence of a...

P. G. Brewer

1972-01-01

241

Metallurgy and Processing of Marine Manganese Nodules  

Microsoft Academic Search

This paper reviews the state of the art in processing and extraction of ocean floor manganese nodules. It briefly reviews the mining sites where the abundant rich nodules occur and also discusses the metal distribution in nodules in view of economical processing and extraction of these metal values.The paper discloses in a detailed manner the physical and chemical characteristics of

D. W. FUERSTENAU; K. N. HAN

1983-01-01

242

Original article Studies on differential manganese tolerance  

E-print Network

(Oryza sativa) cultivars were tested for their tolerance to different levels of man- ganese (Mn+2) (2.0 µ tested as markers of manganese toxicity. Measurements as early as 48 hours after the germination did with increased per- oxidase activity and decreased catalase activity in different cultivars of mung bean and rice

Boyer, Edmond

243

ADVERSE HEALTH EFFECTS FROM ENVIRONMENTAL MANGANESE EXPOSURE.  

EPA Science Inventory

The ubiquitous element, manganese (Mn), is an essential nutrient, but toxic at excessive exposure levels. Therefore, the US EPA set guideline levels for Mn exposure through inhalation (reference concentration-RfC=0.05 ?g/m3) and ingestion (reference dose-RfD=0.14 mg/kg/day (10 mg...

244

Kinetics of Redox Processes in Manganese Oxides  

Microsoft Academic Search

In this work, we studied specific features of redox processes in manganese oxides Mn 2 O 3 and Mn 3 O 4 . The maximal threshold particle size that ensures the irreversible transition of ? -Mn 2 O 3 into hausmannite was determined. In the narrow temperature range of 810 820 , an overcooled fine powder of hausmannite was found

V. B. Fetisov; A. V. Fetisov; N. V. Korchemkina; L. A. Ovchinnikova; E. A. Pastukhov; A. Ya. Fishman

2002-01-01

245

Risk Assessment of an Essential Element: Manganese  

Microsoft Academic Search

Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Mn is present in most tissues of all living organisms and is present naturally in rocks, soil, water, and food. High-dose oral, parenteral, or inhalation exposures are associated with increased tissue Mn levels that may lead to development of

Annette B. Santamaria; Sandra I. Sulsky

2010-01-01

246

21 CFR 73.2775 - Manganese violet.  

Code of Federal Regulations, 2010 CFR

...ammonium pyrophosphate complex having the approximate formula: Mn(III)NH4 P2 O7 . (b) Specifications. Manganese...not more than 1 part per million. Total color, based on Mn content in as is sample, not less than 93 percent....

2010-04-01

247

Soil Manganese Enrichment from Industrial Inputs: A Gastropod Perspective  

PubMed Central

Manganese is one of the most abundant metal in natural environments and serves as an essential microelement for all living systems. However, the enrichment of soil with manganese resulting from industrial inputs may threaten terrestrial ecosystems. Several studies have demonstrated harmful effects of manganese exposure by cutaneous contact and/or by soil ingestion to a wide range of soil invertebrates. The link between soil manganese and land snails has never been made although these invertebrates routinely come in contact with the upper soil horizons through cutaneous contact, egg-laying, and feeding activities in soil. Therefore, we have investigated the direct transfer of manganese from soils to snails and assessed its toxicity at background concentrations in the soil. Juvenile Cantareus aspersus snails were caged under semi-field conditions and exposed first, for a period of 30 days, to a series of soil manganese concentrations, and then, for a second period of 30 days, to soils with higher manganese concentrations. Manganese levels were measured in the snail hepatopancreas, foot, and shell. The snail survival and shell growth were used to assess the lethal and sublethal effects of manganese exposure. The transfer of manganese from soil to snails occurred independently of food ingestion, but had no consistent effect on either the snail survival or shell growth. The hepatopancreas was the best biomarker of manganese exposure, whereas the shell did not serve as a long-term sink for this metal. The kinetics of manganese retention in the hepatopancreas of snails previously exposed to manganese-spiked soils was significantly influenced by a new exposure event. The results of this study reveal the importance of land snails for manganese cycling in terrestrial biotopes and suggest that the direct transfer from soils to snails should be considered when precisely assessing the impact of anthropogenic Mn releases on soil ecosystems. PMID:24454856

Bordean, Despina-Maria; Nica, Dragos V.; Harmanescu, Monica; Banatean-Dunea, Ionut; Gergen, Iosif I.

2014-01-01

248

Thermodynamic modelling of the formation of zinc-manganese ferrite spinel in electric arc furnace dust.  

PubMed

Electric arc furnace dust is generated when automobile scrap, containing galvanized steel, is remelted in an electric arc furnace. This dust is considered as a hazardous waste in most countries. Zinc is a major component of the dust and can be of significant commercial value. Typically, the majority of the zinc exists as zinc oxide (ZnO) and as a zinc-manganese ferrite spinel ((Zn(x)Mn(y)Fe(1-x-y))Fe(2)O(4)). The recovery of the zinc from the dust in metal recycling and recovery processes, particularly in the hydrometallurgical extraction processes, is often hindered by the presence of the mixed ferrite spinel. However, there is a paucity of information available in the literature on the formation of this spinel. Therefore, in the present research, the equilibrium module of HSC Chemistry 6.1 was utilized to investigate the thermodynamics of the formation of the spinel and the effect of variables on the amount and the composition of the mixed ferrite spinel. It is proposed that the mixed ferrite spinel forms due to the reaction of iron-manganese particulates with both gaseous oxygen and zinc, at the high temperatures in the freeboard of the furnace above the steel melt. Based on the thermodynamic predictions, methods are proposed for minimizing the formation of the mixed ferrite spinel. PMID:20356673

Pickles, C A

2010-07-15

249

Wear resistance of steels for bimetallic farm machinery parts  

Microsoft Academic Search

1.The wear resistance of steels for soil-cutting tools can be increased 3050% by increasing the carbon content from 1.5 to 2%, the chromium content from 6 to 12%, and the addition of 1.52.0% Ti and V.2.It was found that carbon reduces the technological ductility the most (at 2.50% C the limit heating temperature is 1150C).3.Vanadium, titanium, manganese, and silicon within

S. A. Golovanenko; A. N. Rozenbaum; S. I. Bulat; A. S. Tikhonov; V. S. Shumskii

1969-01-01

250

Cation distribution, structure and magnetic properties of lithium manganese iron oxide spinel solid solutions  

SciTech Connect

Single phase cubic spinel compounds Li {sub x}Mn{sub 1+x}Fe{sub 2-2x}O{sub 4} (x = 0, ..., 1) were obtained by thermal decomposition of freeze-dried formate solutions of appropriate composition. The samples were characterized by X-ray powder diffraction and Rietveld refinement, XANES, {sup 57}Fe Moessbauer spectroscopy and magnetization measurements. The combination of these methods provides useful conclusions concerning the structure, cation distribution and properties of the spinel solid solutions. The Li {sub x}Mn{sub 1+x}Fe{sub 2-2x}O{sub 4} samples contain Mn(II) and Mn(III) or Mn(III) and Mn(IV) for x < 0.5 or x > 0.5, respectively. With the increase of x the portion of Li ions occupying tetrahedral sites increases and becomes 100% at about x = 4/7. In spite of the preferred occupation of octahedral sites by manganese(III), the experimental results can only be explained by a partial occupation also of tetrahedral sites by Mn(III). An increase of M {sub S} with the increase of x (expected for a preferred substitution of magnetic ions in tetrahedral sites by non-magnetic Li ions) is not observed. It should be prevented by the decreasing cooperative coupling effects due to the reduction of the iron content.

Wende, C. [Institute of Inorganic Chemistry, Dresden University of Technology, 01062 Dresden (Germany); Olimov, Kh. [Institute of Physics, University of Bonn, 53115 Bonn (Germany); Modrow, H. [Institute of Physics, University of Bonn, 53115 Bonn (Germany); Wagner, F.E. [Physics Department, Technical University of Munich, 85748 Garching (Germany); Langbein, H. [Institute of Inorganic Chemistry, Dresden University of Technology, 01062 Dresden (Germany)]. E-mail: Hubert.Langbein@chemie.tu-dresden.de

2006-08-10

251

The possibility using converter slag; a by-product of steel factory, as an iron fertilizer  

Microsoft Academic Search

This study investigates the effect of converter slag- a by-product of steel industry- as an iron fertilizer on Fe and pH of some calcareous soils. Slag used contained approximately 24% of iron oxides plus a relatively large amount of calcium, silicon, phosphorus, and manganese. An incubation study was conducted with 3 calcareous soils for up to 2 months and the

A. Mohammadi Torkashvand; Islamic Azad

2010-01-01

252

Effect of Steel Converter Sludge as Iron Fertilizer and Soil Amendment in Some Calcareous Soils  

Microsoft Academic Search

The possibility of using converter sludge, a steel factory by-product, as an iron (Fe) fertilizer and amendment in some calcareous soils was investigated. This compound contains 64% Fe oxides plus large amounts of some other elements such as calcium (Ca), silicon (Si), manganese (Mn), phosphorus (P), and potassium (K). Different mixtures of converter sludge with sulfuric acid, organic matter and

A. Abbaspour; M. Kalbasi; H. Shariatmadari

2005-01-01

253

Hardness survey of cold-worked and heat-treated JBK-75 stainless steel alloy  

Microsoft Academic Search

The alloy JBK-75, an age-hardenable austenitic stainless steel, is similar to commercial A-286, but has certain chemistry modifications to improve weldability and hydrogen compatibility. The principal changes are an increase in nickel and a decrease in manganese with lower limits on carbon, phosphorus, sulfur, silicon, and boron. In this study, the effects of solutionizing time and temperature, quench rate, cold

R. J. Jackson; R. L. Lucas

1977-01-01

254

Maternal and early life exposure to manganese in rural Bangladesh.  

PubMed

Manganese exposure and biomarker concentrations during early pregnancy and lactation were investigated in 408 women living in an area with elevated concentrations of both arsenic and manganese in drinking water derived from wells. About 40% of the water samples had manganese concentrations above the World Health Organization's guideline value and showed a strong inverse correlation with arsenic concentrations. Water manganese was found to correlate to urine concentrations, but not to blood or breast milk concentrations. No correlations were found among manganese concentrations in urine, blood, or breast milk. Compared to other populations, manganese concentrations in both urine and blood, but not breast milk, were elevated in the Bangladeshi women and more similar to those of occupationally exposed groups. The lack of associations with water manganese is likely due to variable exposure via water and food, and differences in bioavailability, as well as a complex and/or strict regulation of intestinal manganese absorption, in turn being influenced by nutritional as well as physiological and genetic factors. The results indicate that elevated maternal manganese exposure does not necessarily lead to exposure of breast-fed infants, stressing the importance of breast feeding in high manganese areas. However, the implications of fetal exposurefrom elevated maternal exposure need further investigation. PMID:19452922

Ljung, Karin S; Kippler, Maria J; Goessler, Walter; Grandr, G Margaretha; Nermell, Barbro M; Vahter, Marie E

2009-04-01

255

A simple route to synthesize manganese germanate nanorods  

SciTech Connect

Manganese germanate nanorods have been synthesized by a simple route using germanium dioxide and manganese acetate as the source materials. X-ray diffraction observation shows that the nanorods are composed of orthorhombic and monoclinic manganese germanate phases. Scanning electron microscopy and transmission electron microscopy observations display that the manganese germanate nanorods have flat tips with the length of longer than 10 micrometers and diameter of 60-350 nm, respectively. The role of the growth conditions on the formation of the manganese germanate nanorods shows that the proper selection and combination of the growth conditions are the key factor for controlling the formation of the manganese germanate nanorods. The photoluminescence spectrum of the manganese germanate nanorods exhibits four fluorescence emission peaks centered at 422 nm, 472 nm, 487 nm and 530 nm showing the application potential for the optical devices. - Research Highlights: {yields} Manganese germanate nanorods have been synthesized by simple hydrothermal process. {yields} The formation of manganese germanate nanorods can be controlled by growth conditions. {yields} Manganese germanate nanorods exhibit good PL emission ability for optical device.

Pei, L.Z., E-mail: lzpei1977@163.com; Yang, Y.; Yuan, C.Z.; Duan Taike; Zhang Qianfeng

2011-06-15

256

Manganese binding proteins in human and cow's milk  

SciTech Connect

Manganese nutrition in the neonatal period is poorly understood, due in part to a lack of information on the amount of manganese in infant foods and its bioavailability. Since the molecular localization of an element in foods is one determinant of its subsequent bioavailability, a study was made of the binding of manganese in human and cow's milk. An extrinsic label of /sup 54/Mn was shown to equilibrate isotopically with native manganese in milks and formulas. Milk samples were separated into fat, casein and whey by ultracentrifugation. In human milk, the major part (71%) of manganese was found in whey, 11% in casein and 18% in the lipid fraction. In contrast, in cow's milk, 32% of total manganese was in whey, 67% in casein and 1% in lipid. Within the human whey fraction, most of the manganese was bound to lactoferrin, while in cow's whey, manganese was mostly complexed to ligands with molecular weights less than 200. The distribution of manganese in formulas was closer to that of human milk than of cow's milk. The bioavailability of manganese associated with lactoferrin, casein and low molecular weight complexes needs to be assessed.

Loennerdal, B.; Keen, C.L.; Hurley, L.S.

1985-03-01

257

Manganese oxide cathodes for rechargeable batteries  

NASA Astrophysics Data System (ADS)

Manganese oxides are considered as promising cathodes for rechargeable batteries due to their low cost and low toxicity as well as the abundant natural resources. In this dissertation, manganese oxides have been investigated as cathodes for both rechargeable lithium and alkaline batteries. Nanostructured lithium manganese oxides designed for rechargeable lithium cells have been synthesized by reducing lithium permanganate with methanol or hydrogen in various solvents followed by firing at moderate temperatures. The samples have been characterized by wet-chemical analyses, thermal methods, spectroscopic methods, and electron microscopy. It has been found that chemical residues in the oxides such as carboxylates and hydroxyl groups, which could be controlled by varying the reaction medium, reducing agents, and additives, make a significant influence on the electrochemical properties. The Li/Mn ratio in the material has also been found to be a critical factor in determining the rechargeability of the cathodes. The optimized samples exhibit a high capacity of close to 300 mAh/g with good cyclability and charge efficiency. The high capacity with a lower discharge voltage may make these nanostructured oxides particularly attractive for lithium polymer batteries. The research on the manganese oxide cathodes for alkaline batteries is focused on an analysis of the reaction products generated during the charge/discharge processes or by some designed chemical reactions mimicking the electrochemical processes. The factors influencing the formation of Mn3O4 in the two-electron redox process of delta-MnO2 have been studied with linear sweep voltammetry combined with X-ray diffraction. The presence of bismuth, the discharge rate, and the microstructure of the electrodes are found to affect the formation of Mn3O4, which is known to be electrochemically inactive. A faster voltage sweep and a more intimate mixing of the manganese oxide and carbon in the cathode are found to suppress the formation of Mn3O4. Bismuth has also been found to be beneficial in the one-electron process of gamma-MnO 2 when incorporated into the cathode. The results of a series of chemical reactions reveal that bismuth is blocking some reaction paths leading to the unwanted birnessite or Mn3O4. Barium is also found to play a similar role, but it is less effective than bismuth for the same amount of additive. Optimization of the additives has the potential to make the rechargeable alkaline cells based on manganese oxides to successfully compete with other rechargeable systems due to their low cost, environmental friendliness, and excellent safety features.

Im, Dongmin

258

Fracture toughness of stainless steel welds  

SciTech Connect

The effects of temperature, composition and weld-process variations on the fracture toughness behavior for Types 308 and 16-8-2 stainless steel (SS) welds were examined using the multiple-specimen J/sub R/-curve procedure. Fracture characteristics were found to be dependent on temperature and weld process but not on filler material. Gas-tungsten-arc (GTA) welds exhibited the highest fracture toughness, a shielded metal-arc (SMA) weld exhibited an intermediate toughness and submerged-arc (SA) welds yielded the lowest toughness. Minimum-expected fracture properties were defined from lower-bound J/sub c/ and tearing modulus values generated here and in previous studies. Fractographic examination revealed that microvoid coalescence was the operative fracture mechanism for all welds. Second phase particles of manganese silicide were found to be detrimental to the ductile fracture behavior because they separated from the matrix during the initial stages of plastic straining. In SA welds, the high density of inclusions resulting from silicon pickup from the flux promoted premature dimple rupture. The weld produced by the SMA process contained substantially less manganese silicide, while GTA welds contained no silicide inclusions. Delta ferrite particles present in all welds were substantially more resistant to local failure than the silicide phase. In welds containing little or no manganese silicide, delta ferrite particles initiated microvoid coalescence but only after extensive plastic straining.

Mills, W.J.

1985-11-01

259

Development of third generation advanced high strength steels  

NASA Astrophysics Data System (ADS)

Lightweight duplex steels with combinations of either bainite, acicular ferrite, and austenite or martensite and austenite were investigated as third generation advanced high strength steels targeted for automotive applications. Large additions of manganese (> 13 wt%) and carbon (<0.2wt%) were employed to stabilize the austenite phase. Silicon additions between 1 and 2 wt% were added to suppress cementite formation. Strength and ductility were increased while density was decreased with aluminum additions between 2.4 and 5.5 wt% to the steel. This research addressed the dependence of alloying on microstructures and mechanical behavior for high manganese and aluminum duplex steels that were cast and subsequently hot rolled. Duplex steels with different volume fractions of primary delta-ferrite were used to study the crystallography of austenite fanned during the peritectic reaction. Solute profiles across the peritectic interface showed aluminum segregated near the interface which promoted bainitic ferrite formation. Thermal treatments were used to manipulate the concentration and type of oxides and the ferrite plate density was found to correlate with inclusions of low misfit in steels with austenite grain size of 16.5 microm. A steel with bainite and acicular ferrite produced an ultimate tensile strength of 970 MPa and elongation of 40%. The mechanical prope1iies depended on the strengths and size of the microstructural constituents. Work hardening behavior was examined in a steel exhibiting multiple martensitic transformation induced plasticity (gamma-austenite?epsilon-smartensite?alpha-martensite). A strain hardening exponent as high as 1.4 was observed with ultimate tensile strength and elongation as high as 1,165 MPa and 34%.

McGrath, Meghan Colleen

260

Glutamate\\/Aspartate Transporter (GLAST), Taurine Transporter and Metallothionein mRNA Levels are Differentially Altered in Astrocytes Exposed to Manganese Chloride, Manganese Phosphate or Manganese Sulfate  

Microsoft Academic Search

Manganese (Mn)-induced neurotoxicity can occur due to environmental exposure (air pollution, soil, water) and\\/or metabolic aberrations (decreased biliary excretion). High brain manganese levels lead to oxidative stress, as well as alterations in neurotransmitter metabolism with concurrent neurobehavioral deficits. Based on the few existing studies that have examined brain regional Mn concentration, it is likely that in pathological conditions, Mn concentration

Keith M. Erikson; Robert L. Suber; Michael Aschner

2002-01-01

261

International Strategic Minerals Inventory summary report; manganese  

USGS Publications Warehouse

Major world resources of manganese, a strategic mineral commodity, are described in this summary report of information in the International Strategic Minerals Inventory {ISMI). ISMI is a cooperative data-collection effort of earth-science and mineral-resource agencies in Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, and the United States of America. This report, designed to be of benefit to policy analysts, contains two parts. Part I presents an overview of the resources and potential supply of manganese on the basis of inventory information. Part II contains tables of some of the geologic information and mineral-resource and production data that were collected by ISMI participants.

DeYoung, John H.; Sutphin, David M.; Cannon, William F.

1984-01-01

262

Manganese accumulation in the brain: MR imaging  

Microsoft Academic Search

Manganese (Mn) accumulation in the brain is detected as symmetrical high signal intensity in the globus pallidi on T1-weighted\\u000a MR images without an abnormal signal on T2-weighted images. In this review, we present several cases of Mn accumulation in\\u000a the brain due to acquired or congenital diseases of the abdomen including hepatic cirrhosis with a portosystemic shunt, congenital\\u000a biliary atresia,

A. Uchino; T. Noguchi; K. Nomiyama; Y. Takase; T. Nakazono; J. Nojiri; S. Kudo

2007-01-01

263

Electrochemical lithium intercalation in disordered manganese oxides  

Microsoft Academic Search

Four highly disordered manganese oxides were prepared by reduction of sodium permanganate by chloride, iodide, hydrogen peroxide or oxalate in aqueous medium containing a large excess of Li+ ions, yielding hydrated oxides with Mn valence in the range 3.803.92. Thermogravimetric studies showed that the iodide-reduced oxide can be dehydrated to 92% at 240C, while the other three ones retain water

A Ibarra Palos; M Anne; P Strobel

2001-01-01

264

Manganese olivine II: point defect relaxation  

Microsoft Academic Search

To investigate the point defect chemistry and the kinetic properties of manganese olivine Mn2SiO4, the point defect relaxation time (tau) characterizing the rate of re-equilibration of electrical conductivity following a change in oxygen fugacity was measured for single crystals oriented for electrical conduction along the [010] direction. The experiments were carried out at temperatures T = 1173-1473 K and oxygen

Q. Bai; Z.-C. Wang; D. L. Kohlstedt

1998-01-01

265

Manganese olivine II: point defect relaxation  

Microsoft Academic Search

To investigate the point defect chemistry and the kinetic properties of manganese olivine Mn2SiO4, the point defect relaxation time (?) characterizing the rate of re-equilibration of electrical conductivity following a\\u000a change in oxygen fugacity was measured for single crystals oriented for electrical conduction along the [010] direction. The\\u000a experiments were carried out at temperatures T?=?11731473?K and oxygen fugacities with the

Q. Bai; Z.-C. Wang; D. L. Kohlstedt

1998-01-01

266

The cosmic origin of carbon and manganese  

E-print Network

[ABRIDGED] We have determined carbon abundances for 51 dwarf stars and manganese abundances for 95 dwarf stars in two distinct and well defined stellar populations - the Galactic thin and thick disks. As these two populations have different chemical histories we have been able to, through a differential abundance analysis using high-resolution spectra, constrain the formation sites for carbon and manganese in the Galactic disk(s). The analysis of carbon is based on the forbidden [C I] line at 872.7 nm which is an abundance indicator that is insensitive to errors in the stellar atmosphere parameters. Combining these data with our previously published oxygen abundances, based on the forbidden [O I] line at 630.0 nm, we can form very robust [C/O] ratios that we then used to investigate the origin of carbon and the chemical evolution of the Galactic thin and thick disks..... Our interpretation of our abundance trends is that the sources that are responsible for the carbon enrichment in the Galactic thin and thick disks have operated on a time-scale very similar to those that are responsible for the Fe and Y enrichment (i.e., SNIa and AGB stars, respectively). For manganese, when comparing our Mn abundances with O abundances for the same stars we find that the abundance trends in the stars with kinematics typical of the thick disk can be explained by metallicity dependent yields from SN II. Furthermore, the [Mn/O] versus [O/H] trend in the halo is flat. We conclude that the simplest interpretation of our data is that manganese most likely is produced in SN II and that the Mn yields for such SNae must be metallicity dependent.

Thomas Bensby; Sofia Feltzing

2008-09-24

267

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).  

Code of Federal Regulations, 2011 CFR

...treated manganese ferrite with acrylic ester polymer (generic). 721.10223 Section...treated manganese ferrite with acrylic ester polymer (generic). (a) Chemical substance...treated manganese ferrite with acrylic ester polymer (PMN P-09-582) is subject to...

2011-07-01

268

78 FR 54269 - Electrolytic Manganese Dioxide From Australia and China; Institution of Five-Year Reviews  

Federal Register 2010, 2011, 2012, 2013

...Electrolytic Manganese Dioxide From Australia and China; Institution of Five-Year...on electrolytic manganese dioxide from Australia and China would be likely to lead to...of electrolytic manganese dioxide from Australia and China (73 FR 58537-58539)....

2013-09-03

269

40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Styrenyl surface treated manganese ferrite (generic). 721.10222...721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical...generically as styrenyl surface treated manganese ferrite (PMN P-09-581) is...

2012-07-01

270

40 CFR 424.60 - Applicability; description of the electrolytic manganese products subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the electrolytic manganese products subcategory. 424.60 Section...POINT SOURCE CATEGORY Electrolytic Manganese Products Subcategory 424.60 ...Applicability; description of the electrolytic manganese products subcategory. The...

2013-07-01

271

40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Styrenyl surface treated manganese ferrite (generic). 721.10222...721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical...generically as styrenyl surface treated manganese ferrite (PMN P-09-581) is...

2011-07-01

272

40 CFR 721.10529 - Cobalt iron manganese oxide, carboxylic acid-modified (generic).  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Cobalt iron manganese oxide, carboxylic acid-modified...Substances 721.10529 Cobalt iron manganese oxide, carboxylic acid-modified...identified generically as cobalt iron manganese oxide, carboxylic...

2013-07-01

273

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Styrenyl surface treated manganese ferrite with acrylic ester polymer...721.10223 Styrenyl surface treated manganese ferrite with acrylic ester polymer...generically as styrenyl surface treated manganese ferrite with acrylic ester...

2012-07-01

274

40 CFR 424.60 - Applicability; description of the electrolytic manganese products subcategory.  

...Applicability; description of the electrolytic manganese products subcategory. 424.60 Section...POINT SOURCE CATEGORY Electrolytic Manganese Products Subcategory 424.60 ...Applicability; description of the electrolytic manganese products subcategory. The...

2014-07-01

275

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Styrenyl surface treated manganese ferrite with acrylic ester polymer...721.10223 Styrenyl surface treated manganese ferrite with acrylic ester polymer...generically as styrenyl surface treated manganese ferrite with acrylic ester...

2013-07-01

276

40 CFR 424.60 - Applicability; description of the electrolytic manganese products subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the electrolytic manganese products subcategory. 424.60 Section...POINT SOURCE CATEGORY Electrolytic Manganese Products Subcategory 424.60 ...Applicability; description of the electrolytic manganese products subcategory. The...

2011-07-01

277

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).  

...2014-07-01 false Styrenyl surface treated manganese ferrite with acrylic ester polymer...721.10223 Styrenyl surface treated manganese ferrite with acrylic ester polymer...generically as styrenyl surface treated manganese ferrite with acrylic ester...

2014-07-01

278

40 CFR 424.60 - Applicability; description of the electrolytic manganese products subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the electrolytic manganese products subcategory. 424.60 Section...POINT SOURCE CATEGORY Electrolytic Manganese Products Subcategory 424.60 ...Applicability; description of the electrolytic manganese products subcategory. The...

2012-07-01

279

40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Styrenyl surface treated manganese ferrite (generic). 721.10222...721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical...generically as styrenyl surface treated manganese ferrite (PMN P-09-581) is...

2013-07-01

280

40 CFR 424.60 - Applicability; description of the electrolytic manganese products subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the electrolytic manganese products subcategory. 424.60 Section...POINT SOURCE CATEGORY Electrolytic Manganese Products Subcategory 424.60 ...Applicability; description of the electrolytic manganese products subcategory. The...

2010-07-01

281

40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).  

...2014-07-01 false Styrenyl surface treated manganese ferrite (generic). 721.10222...721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical...generically as styrenyl surface treated manganese ferrite (PMN P-09-581) is...

2014-07-01

282

40 CFR 721.10529 - Cobalt iron manganese oxide, carboxylic acid-modified (generic).  

... 2014-07-01 false Cobalt iron manganese oxide, carboxylic acid-modified...Substances 721.10529 Cobalt iron manganese oxide, carboxylic acid-modified...identified generically as cobalt iron manganese oxide, carboxylic...

2014-07-01

283

Manganese toxicity to chlorophyll synthesis in tobacco callus. [Nicotiana tabacum  

SciTech Connect

Tobacco (Nicotiana tabacum) pith explants were grown on manganese containing medium. At moderate concentration (10 millimolar), manganese selectivity inhibited chlorophyll synthesis, resulting initially in growth of white callus. Several weeks later the white callus turned brown due to the accumulation of a pigment identified as protoporphyrin IX by its elution profile using high performance liquid chromatography, by its absorption spectrum, and by its fluorescence properties. At a concentration of 100 millimolar manganese the pigment accumulated without growth of the explant.

Clairmont, K.B.; Hagar, W.G.; Davis, E.A.

1986-01-01

284

Maternal Blood Manganese Levels and Infant Birth Weight  

PubMed Central

Background Manganese is both an essential element and a known neurotoxicant to children. High manganese exposures have been associated with negative reproductive outcomes in animals, but few epidemiologic studies have examined the effects of human fetal manganese exposure. Methods We studied the association between maternal and umbilical cord blood manganese levels and birth weight in a cohort of 470 mother-infant pairs born at term (?37 weeks gestation) in Ottawa County, Oklahoma. Nonlinear spline and quadratic regression models were used to test the hypothesis of an inverted U-shaped relationship between manganese levels and birth weight. Results Mean (standard deviation) concentration of manganese was 2.4 (0.95) ?g/dL in the maternal blood and 4.2 (1.6) ?g/dL in the cord blood. Umbilical cord manganese was not associated with birth weight. A nonlinear relationship was observed between maternal manganese and birth weight after adjusting for potential confounders. Birth weight increased with manganese levels up to 3.1 ?g/L, and then a slight reduction in weight was observed at higher levels. Compared with the 3.1-?g/L point of inflection, birth weight estimates at the 5th (1.3 ?g/L) and 95th (4.0 ?g/L) percentiles of exposure were ?160 g (95% confidence interval = ?286 to ?33) and ?46 g (?38 to 131), respectively. Conclusions Maternal blood manganese levels during pregnancy are associated with birth weight in a nonlinear pattern in full-term infants. These findings suggest that manganese may affect fetal growth. Possible detrimental effects of elevated manganese levels on the fetus should be further examined in more highly exposed populations. PMID:19289966

Zota, Ami R.; Ettinger, Adrienne S.; Bouchard, Maryse; Amarasiriwardena, Chitra J.; Schwartz, Joel; Hu, Howard; Wright, Robert O.

2011-01-01

285

Colloidal Manganese Oxide Precursor to Octahedral Layered, OL-3 Materials  

Microsoft Academic Search

We report the one-pot synthesis of a hexagonal form of a layered manganese oxide material (OL-3) using mild conditions and\\u000a low temperature. The oxidation of an aqueous solution of manganese acetate using tetramethylammonium hydroxide and hydrogen\\u000a peroxide at 4C leads to the formation of a colloidal manganese dioxide solution. Colloidal MnO2 was then flocculated using K ions, forming disordered layered

Jason P. Durand; Josanlet C. Villegas; Sinue Gomez-Mower; Oscar Giraldo; Steven L. Suib

2007-01-01

286

Manganese in Texas Soils and its Relation to Crops.  

E-print Network

on the weight of the crops can be seen by comparing the weights of the crops grown on the portions of soil which received no addition, with the weights of the crops grown on the portions which received manganese sulfate (Mn) and also the crops that received... ....................... Manganese (Mn). .................. Average ....................... Nitrogen, phosphoric acid, potash (NDK) I Average ..................... Nitrogen, phosphoric acid, potash and manganese (NDKMn) / Average ..................... Miller clay, 0...

Carlyle, E. C. (Elmer Cardinal)

1931-01-01

287

Manganese oxide nanowires, films, and membranes and methods of making  

DOEpatents

Nanowires, films, and membranes comprising ordered porous manganese oxide-based octahedral molecular sieves and methods of making the same are disclosed. A method for forming nanowires includes hydrothermally treating a chemical precursor composition in a hydrothermal treating solvent to form the nanowires, wherein the chemical precursor composition comprises a source of manganese cations and a source of counter cations, and wherein the nanowires comprise ordered porous manganese oxide-based octahedral molecular sieves.

Suib, Steven Lawrence (Storrs, CT); Yuan, Jikang (Storrs, CT)

2011-02-15

288

Manganese Inhalation as a Parkinson Disease Model  

PubMed Central

The present study examines the effects of divalent and trivalent Manganese (Mn2+/Mn3+) mixture inhalation on mice to obtain a novel animal model of Parkinson disease (PD) inducing bilateral and progressive dopaminergic cell death, correlate those alterations with motor disturbances, and determine whether L-DOPA treatment improves the behavior, to ensure that the alterations are of dopaminergic origin. CD-1 male mice inhaled a mixture of Manganese chloride and Manganese acetate, one hour twice a week for five months. Before Mn exposure, animals were trained to perform motor function tests and were evaluated each week after the exposure. By the end of Mn exposure, 10 mice were orally treated with 7.5?mg/kg L-DOPA. After 5 months of Mn mixture inhalation, striatal dopamine content decreased 71%, the SNc showed important reduction in the number of TH-immunopositive neurons, mice developed akinesia, postural instability, and action tremor; these motor alterations were reverted with L-DOPA treatment. Our data provide evidence that Mn2+/Mn3+ mixture inhalation produces similar morphological, neurochemical, and behavioral alterations to those observed in PD providing a useful experimental model for the study of this neurodegenerative disease. PMID:21209715

Ordonez-Librado, Jose Luis; Anaya-Martinez, Veronica; Gutierrez-Valdez, Ana Luisa; Colin-Barenque, Laura; Montiel-Flores, Enrique; Avila-Costa, Maria Rosa

2011-01-01

289

Manganese abundances in Galactic bulge red giants  

E-print Network

Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut beween the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Gala...

Barbuy, B; Zoccali, M; Minniti, D; Renzini, A; Ortolani, S; Gomez, A; Trevisan, M; Dutra, N

2013-01-01

290

Nonmetallic inclusions in a chromium steel intended for the power engineering industry  

NASA Astrophysics Data System (ADS)

The behavior of oxygen in the course of manufacturing large steel ingots containing 1.5-20% Cr, the formation of oxides depending on the contents of deoxidizing agents and oxygen, and the composition of the oxide phase in ingots and forgings made of the steel are considered. The steel is manufactured using an arc steel-melting furnace and unit for complex treatment of steel (ASF-ACSPU technology) and the ASF-ACSPU technology and electroslag remelting (ESR). It is shown that the oxide phase composition depends on the contents of strong deoxidizing agents and oxygen and the development of secondary oxidation. Chromium- and manganese-containing spinels are characteristic species of the secondary and tertiary oxides in the chromium steel in the case of deficient aluminum and silicon.

Kolpishon, E. Yu.; Mal'Ginov, A. N.; Romashkin, A. N.; Durynin, V. A.; Afanas'ev, S. Yu.; Shitov, E. V.; Afanas'eva, L. T.; Batov, Yu. M.

2010-06-01

291

Lithium manganese oxide with excellent electrochemical performance prepared from chemical manganese dioxide for lithium ion batteries  

NASA Astrophysics Data System (ADS)

Chemical manganese dioxide (CMD) is synthesized by the SEDEMA process and adopted as a precursor for lithium manganese oxide with a spinel structure (LMO). LMO is also prepared from electrolytic manganese dioxide (EMD) as a reference for comparison. X-ray diffraction (XRD) shows that CMD is composed of ?-MnO2, and scanning electron microscopy (SEM) with transmission electron microscopy (TEM) shows that the nanorods cover a spherical core with a diameter < 1 ?m. The LMO prepared from CMD shows a much better rate capability and cycle life performance than that from EMD at high temperatures and high current densities. The excellent electrochemical performance is attributed to the structural stability during charge and discharge and the morphology of the LMO, a loose aggregation of the octahedral particles with a uniform size (<1 ?m) and shape, which originated from that of CMD.

Lee, Jae-Won; Kim, Jun-Il; Roh, Kwang Chul

2012-09-01

292

Cryogenic properties of new austenitic stainless steel for fusion reactor superconducting magnets  

NASA Astrophysics Data System (ADS)

A non-magnetic austenitic stainless steel has been developed, which has an adequate combination of yield strength and fracture toughness at liquid helium temperature, as a candidate structural material for fusion reactor superconducting magnets. The salient feature of the steel is its low-temperature toughness preserved after aging equivalent to the wind-and-react heat treatment of Nb 3Sn superconducting coil. The steel also keeps its toughness after electron beam welding. Its composition is characterized by addition of vanadium and nitrogen to 25Cr-14Ni-0.5Mo austenitic stainless steel. Microscopic observations have suggested that finely dispersed precipitates, presumably vanadium carbonitrides, are responsible for the excellent cryogenic mechanical properties.

Nohara, Kiyohiko; Shimotomai, Michio; Habu, Yasuhiro

1989-12-01

293

Deposition of manganese in a drinking water distribution system.  

PubMed Central

The deposition of manganese in a water distribution system with manganese-related "dirty water" problems was studied over a 1-year period. Four monitoring laboratories with Robbins biofilm sampling devices fitted to the water mains were used to correlate the relationship among manganese deposition, the level of manganese in the water, and the chlorination conditions. Manganese deposition occurred by both chemical and microbial processes. Chemical deposition occurred when Mn(II) not removed during water treatment penetrated the filters and entered the distribution system, where it was oxidized by chlorine and chlorine dioxide used for disinfection. Microbial deposition occurred in areas with insufficient chlorination to control the growth of manganese-depositing biofilm. At 0.05 mg of Mn(II) per liter, the chemical deposition rate was much greater than microbial deposition. Significant deposition occurred at 0.03 mg of manganese per liter, and dirty water complaints were not eliminated until manganese levels were continuously less than 0.02 mg/liter and chlorination levels were greater than 0.2 mg/liter. A guideline level of 0.01 mg of manganese per liter is recommended. Images PMID:2317040

Sly, L I; Hodgkinson, M C; Arunpairojana, V

1990-01-01

294

A biokinetic model for manganese for use in radiation protection  

SciTech Connect

The ICRP is updating its recommendations regarding occupational exposure to radionuclides including the biokinetic models used to derive dose coefficients and assess bioassay data for internally deposited radionuclides. This report reviews biokinetic data for manganese and proposes a biokinetic model for systemic manganese consistent with the current database. The model provides a more detailed and biologically realistic description of the movement of absorbed manganese in the body than the model currently recommended by the International Commission on Radiological Protection (ICRP). The proposed model and current ICRP model yield broadly similar estimates of dose per unit activity of inhaled or ingested radio-manganese but differ substantially with regard to interpretation of bioassay data.

Leggett, Richard Wayne [ORNL

2011-01-01

295

Manganese-enhanced magnetic resonance microscopy of mineralization  

USGS Publications Warehouse

Paramagnetic manganese (II) can be employed as a calcium surrogate to sensitize magnetic resonance microscopy (MRM) to the processing of calcium during bone formation. At high doses, osteoblasts can take up sufficient quantities of manganese, resulting in marked changes in water proton T1, T2 and magnetization transfer ratio values compared to those for untreated cells. Accordingly, inductively coupled plasma mass spectrometry (ICP-MS) results confirm that the manganese content of treated cell pellets was 10-fold higher than that for untreated cell pellets. To establish that manganese is processed like calcium and deposited as bone, calvaria from the skull of embryonic chicks were grown in culture medium supplemented with 1 mM MnCl2 and 3 mM CaCl2. A banding pattern of high and low T2 values, consistent with mineral deposits with high and low levels of manganese, was observed radiating from the calvarial ridge. The results of ICP-MS studies confirm that manganese-treated calvaria take up increasing amounts of manganese with time in culture. Finally, elemental mapping studies with electron probe microanalysis confirmed local variations in the manganese content of bone newly deposited on the calvarial surface. This is the first reported use of manganese-enhanced MRM to study the process whereby calcium is taken up by osteoblasts cells and deposited as bone. ?? 2007 Elsevier Inc. All rights reserved.

Chesnick, I.E.; Todorov, T.I.; Centeno, J.A.; Newbury, D.E.; Small, J.A.; Potter, K.

2007-01-01

296

Cathodic current enhancement via manganese and oxygen related reactions in marine biofilms  

NASA Astrophysics Data System (ADS)

Corrosion is a threat that has economic, and environmental impacts worldwide. Many types of corrosive attack are the subject of ongoing research. One of these areas of research is microbiologically influenced corrosion, which is the enhancement and/or initiation of corrosion events caused by microorganisms. It is well known that colonies of microorganisms can enhance cathodic currents through biofilm formation. The aim of the present work was to elucidate the role of manganese in enhancing cathodic currents in the presence of biofilms. Repeated polarizations conducted in Delaware Bay waters, on biofilm coated Cr identified potentially sustainable reduction reactions. The reduction of MnO2 and the enhancement of the oxygen reduction reaction (ORR) were proven to be factors that influence cathodic current enhancement. The removal of ambient oxygen during polarizations resulted in a shutdown of cathodic current enhancement. These field data led to an exploration of the synergistic relationship between MnO2 and the ORR. Laboratory studies of the catalysis of peroxide disproportionation by MnO2 were monitored using a hanging mercury drop electrode. Experiments were run at an ambient sweater pH of 8 and pH 9, which simulated the near-surface conditions typical of cathodes immersed in seawater. Rapid reoxidation at the more basic pH was shown to allow manganese to behave as a persistent catalyst under the typical electrochemical surface conditions of a cathode. As a result a mechanism for ORR enhancement by manganese was proposed as a unique mechanism for cathodic current enhancement in biofilms. A separate field study of Delaware biofilms on stainless steel coupled to a sacrificial Al anode was carried out to identify the ORR enhancement mechanism and sustainable redox reactions at the cathode. Chemical treatments of glutaraldehyde and formaldoxime were applied to cathodes with biofilms to distinguish between enzymatic and MnO2 related ORR enhancement. The results ruled out the enzymatic catalysis of ORR and supported the catalysis by MnO2. Sustainable redox reactions at the cathode were evaluated by monitoring the cathodic current of biofilm coated stainless steel for a year under different polarization intensities. The results showed that sustainable cathodic reactions were present in marine biofilms but their influence on the cathodic current was negligible until a potential was reached where the ORR could take place. Additionally seasonal variability was observed in the enhanced cathodic current in Delaware Bay biofilms. This was attributed to the seasonal variability of manganese in the water column.

Strom, Matthew James

297

Subcellular and gel chromatographic distribution of manganese in the mouse brain: relation to the chemical form of chronically-ingested manganese.  

PubMed

The subcellular distribution of manganese and the binding characteristics of manganese to protein in the mouse brain were examined on G-75 Sephadex gel columns. Four manganese compounds were included at 2 g/kg in each food eaten by ddY mice for 12 months. The cerebral cortex manganese concentrations in the virtually insoluble manganese compounds were significantly higher than those in the control group. The brain striatal subcellular distribution and gel chromatographic profiles of manganese were similar among the divalent manganese compounds. On the contrary, the behaviour of MnO2 was little different from the divalent manganese compounds. There was more manganese associated with fast-migrating ligands in the striatal cytosol of the manganese-exposed group than in the control groups. PMID:8475509

Komura, J; Sakamoto, M

1993-03-01

298

Austenitic steels at low temperatures  

SciTech Connect

The search for alternate energy sources has resulted in the development of prototype fusion and MHD reactors, which both usually require the use of magnetic fields for plasma confinement and concentration. In many cases, the use of superconducting magnets seems to be more economical, but the high magnetic fields create large forces and the complexities of the conceptual reactors severely limit space. These restrictions call for a strong structural alloy that is both weldable and nonmagnetic for service at liquid helium temperature. This volume examines high strength austenitic steels for use in fusion and MHD reactors currently under design. Created to be strong at low temperatures-by the addition of nitrogen-and stable through the addition of manganese and/or nickel, the austenitic alloys have been improved in Japan and the United States. Authored by leading researchers doing much of the work on austenitic steels today, the book presents a thorough review of the latest research advances. Several chapters on ferritic cryogenic alloys are also included.

Reed, R.P.; Horiuchi, T.

1983-01-01

299

Manganese exposures in Toronto during use of the gasoline additive, methylcyclopentadienyl manganese tricarbonyl  

Microsoft Academic Search

A year-long population-weighted study of personal exposures to particulate matter (PM2.5) was conducted in Toronto while the manganese-containing additive, methylcyclopentadienyl manganese tricarbonyl (MMT), was present in gasoline at an average level of 11.9 mg Mn\\/l, which was higher than the maximum of 8.3 mg Mn\\/l allowed in the U.S. In this study, 925 three-day personal samples of PM2.5 (air concentration

KENNY S CRUMP

2000-01-01

300

Catalytic Reduction of NO with CO on Active Carbon-Supported Copper, Manganese, and CopperManganese Oxides  

Microsoft Academic Search

The catalytic activity of copper, manganese, and coppermanganese oxide catalysts with respect to NO reduction with CO has been investigated in the temperature range 25300C. Coppermanganese oxide catalysts with Cu:Mn ratios of 1 : 2 and 1 : 1 where the two metals form spinel-like phases have shown the highest activity. With the three kinds of catalysts NO reduction proceeds

Neli B. Stankova; Mariana S. Khristova; Dimitar R. Mehandjiev

2001-01-01

301

An investigation on the sintering behavior of 316L and 17-4PH stainless steel powders for graded composites  

Microsoft Academic Search

This paper presents the densification and microstructure of bilayer structures made from 316L and 17-4PH stainless steels powders during sintering. The requirements for such objects could be magnetic properties at one area of the part and non-magnetic properties at another area of the object. A pressureless solid state sintering method in conjunction with a powder layering technique was used. The

A. Simchi; A. Rota; P. Imgrund

2006-01-01

302

Effect of alkaline and rare-earth metals on the composition of sulfide inclusions and properties of cast steel  

Microsoft Academic Search

1.The addition of alkaline and rare-earth metals to a low-alloy steel changes the composition of the sulfide inclusions. Alkaline-earth elements partially, and rare-earth elements completely, displace manganese in the sulfide inclusions.2.Both the ductile and brittle regions of the fracture surface in both modified and unmodified steels are the same. However, there is somewhat of an increase in the fraction of

A. E. Aksel'rod; V. V. Popov; A. F. Filippenkov

1988-01-01

303

Manganese exposures in Toronto during use of the gasoline additive, methylcyclopentadienyl manganese tricarbonyl.  

PubMed

A year-long population-weighted study of personal exposures to particulate matter (PM2.5) was conducted in Toronto while the manganese-containing additive, methylcyclopentadienyl manganese tricarbonyl (MMT), was present in gasoline at an average level of 11.9 mg Mn/l, which was higher than the maximum of 8.3 mg Mn/l allowed in the U.S. In this study, 925 three-day personal samples of PM2.5 (air concentration of aerosol with an aerodynamic diameter of less than 2.5 microm) were collected, along with a record of participants' occupations, personal habits, surroundings, and activities during sampling. Stationary samples of PM2.5 were collected indoors and outdoors at a subset of participants' homes over the same 3-day periods. Three-day samples of PM2.5 were also collected at fixed locations. Personal exposures to PM2.5 were highly influenced by exposure to tobacco smoke, and were poorly correlated with outdoor levels (Kendall's tau=0.13). The mean concentration of PM2.5 in homes (21 microg/m3) was significantly higher than the mean outdoor level (15 microg/m3). By contrast, the mean PM2.5 Mn concentration (air concentration of Mn in PM2.5) was higher outdoors (9.7 ng/m3) than indoors (5.5 ng/m3). Other than from tobacco smoke, there were no indications of significant indoor sources of PM2.5 Mn in homes. The most important predictor of exposure to PM2.5 was time spent in the subway, and a high level (428 ng/m3) of PM2.5 Mn was measured in the subway. The source of this Mn was hypothesized to be friction erosion of subway rails. Small, but statistically significant correlations were present between personal exposures to PM2.5 Mn and several traffic-related variables (time spent in transit, in a motor vehicle, near a roadway with traffic, and in a parking garage). However, in a stepwise regression that adjusted for weather and personal activities, time in a motor vehicle was the only traffic-related variable significantly associated with PM2.5 Mn, and it was only the 10th most important personal activity variable in the final model. Concentrations of PM2.5 Mn were higher at two fixed locations than outside of participants' homes, which were likely further from high traffic areas than the fixed sites. Likewise, outdoor and fixed site samples collected during periods that included weekend days contained lower air concentrations of Mn than samples collected during weekdays when traffic was heavier. On the other hand, the monthly average concentration of Mn in gasoline was negatively correlated with both outdoor and personal PM2.5 Mn, which suggests that traffic-related sources of Mn other than MMT may be present. After omitting participants with exposure to Mn from certain identifiable non-MMT sources (subway riders, metal workers and persons exposed to tobacco smoke), the average (median) personal exposure of the remaining 325 participants to PM2.5 Mn was reduced from 14 ng/m3 (8.5 ng/m3 ) to 8.3 ng/m3 (7.0 ng/m3). Potential sources of this residual Mn exposure include, in addition to MMT, naturally occurring Mn in the earth's crust, other occupational exposure, airborne release of Mn from industrial operations, and friction erosion of Mn from steel-containing products. Taken together, these facts (elimination of participants with Mn exposure from known non-MMT sources reduced average exposures by 40%, the existence of multiple non-MMT sources of the remaining Mn exposure, and the negative correlation between MMT usage and PM2.5 Mn) suggest that the preponderance of personal Mn exposure was from non-MMT sources. PMID:10910116

Crump, K S

2000-01-01

304

Modeling the environmental fate of manganese from methylcyclopentadienyl manganese tricarbonyl in urban landscapes  

Microsoft Academic Search

The environmental impacts of gasoline additives such as lead (Pb) and Methyl Tertiary Butyl Ether (MTBE) are well documented, leading to the phasing out of these additives. In contrast, little is known about the health and environmental impacts of potential replacement chemicals such as Methylcyclopentadienyl Manganese Tricarbonyl (MMT). The combustion of MMT in gasoline leads to the formation of MnPO4

A. K. Bhuie; O. A. Ogunseitan; R. R. White; M. Sain; D. N. Roy

2005-01-01

305

PRELIMINARY ASSESSMENT OF ATMOSPHERIC METHYLCYCLOPENTADIENYL MANGANESE TRICARBONYL AND PARTICULATE MANGANESE IN SELECTED URBAN SITES  

Microsoft Academic Search

Methylcyclopentadienyl manganese tricarbonyl (MMT: C 9 H 7 MnO 3 ) is an organometallic additive that has been used since 1976 as an octane enhancer in Canadian unleaded gasoline. Very few studies have determined its atmospheric concentrations and only one study offers recent data on its ambient level. This preliminary study aims to assess atmospheric concentrations of MMT and respirable

Christiane Thibault; Greg Kennedy; Lise Gareau; Joseph Zayed

2002-01-01

306

Assessment of the permissible exposure level to manganese in workers exposed to manganese dioxide dust  

Microsoft Academic Search

The prevalence of neuropsychological and respiratory symptoms, lung ventilatory parameters, neurofunctional performances (visual reaction time, eye-hand coordination, hand steadiness, audioverbal short term memory), and several biological parameters (calcium, iron, luteinising hormone (LH), follicle stimulating hormone (FSH), and prolactin concentrations in serum, blood counts, manganese (Mn) concentration in blood and in urine) were examined in a group of workers (n =

H A Roels; P Ghyselen; J P Buchet; E Ceulemans; R R Lauwerys

1992-01-01

307

Addition of Titanium Oxide Inclusions into Liquid Steel to Control Nonmetallic Inclusions  

NASA Astrophysics Data System (ADS)

Titanium oxide inclusions in steel are well known to inhibit grain growth and act as nucleation sites for acicular ferrite because of absorbing manganese from the surrounding steel resulting in a manganese depleted zone around the inclusion. In this article, the inclusions resulting from TiO2 additions to low-alloyed C-Mn-Cr steel were studied. Different types of TiO2 containing materials were added to liquid steel before or during casting to get small titanium-oxide-rich inclusions in steel. The main goals were to find out what happens to TiO2 in liquid steel after addition and during cooling and to study further what type of inclusions are formed in the steel as a result of the TiO2 addition. Based on the thermodynamic calculations and the results of scanning electron microscope (SEM)-energy dispersive spectroscope (EDS) and SEM-electron backscatter diffraction (EBSD) analysis, TiO2 is first reduced to Ti3O5 in liquid steel at high temperatures and then to Ti2O3 during cooling at around 1573 K (1300 C). Both reactions liberate oxygen, which reacts with Ti, Mn, and Al forming complex Ti2O3-rich inclusions. The results also show that TiO2 additions result in more TiOx + MnO inclusions compared with experiments with Ti addition and that the absolute amount of manganese present in the inclusions is much higher in experiments with TiO2 addition than in experiments with Ti additions.

Kivi, Miia; Holappa, Lauri

2012-04-01

308

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria  

PubMed Central

Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 106 acetate-utilizing manganese-reducing cells cm?3 in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments. PMID:22572639

Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

2012-01-01

309

Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide. 2.  

E-print Network

Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide. 2. Results from X-ray Absorption September 23, 2010. Accepted October 1, 2010. Arsenite (AsIII ) oxidation by manganese oxides (Mn-oxides) servestodetoxifyand,undermanyconditions,immobilizearsenic (As) by forming arsenate (AsV ). AsIII oxidation by Mn

Sparks, Donald L.

310

Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide 1.  

E-print Network

Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide 1. Stirred-Flow Experiments B R A N D O September 23, 2010. Accepted October 1, 2010. Manganese-oxides (Mn-oxides) are quite reactive, with respect to arsenite (AsIII ) oxidation. However, studies regarding the pathways of AsIII oxidation, over a range

Sparks, Donald L.

311

Methylcyclopentadienyl manganese tricarbonyl (MMT), plant uptake and effects on metabolism  

Microsoft Academic Search

In the USA and Canada, methylcyclopentadienyl manganese (MMT) is currently added to gasoline to replace tetraethyl lead as an antiknock fuel additive. Manganese concentrations in roadside soil and plants are increasing and correlated with distance from the roadway, traffic volume, plant type, and microhabitat. Radish (Raphanus sativus L.) seedlings were treated for either five or thirty-five days with different levels

Angela R Jones; C. Mel Lytle; Rebekka L Stone; Lee D Hansen; Bruce N Smith

2000-01-01

312

Particulate matter and manganese exposures in Indianapolis, Indiana  

Microsoft Academic Search

The distribution of PM2.5 and manganese (Mn) personal exposures was determined over a 4-month period in Indianapolis, IN, at a time when the gasoline additive, methylcyclopentadienyl manganese tricarbonyl (MMT), was not being used. The data collection period coincided with the data collection period in the Toronto, ON, study, where MMT had been used as a gasoline additive for over 20

E D PELLIZZARI; C A CLAYTON; C E RODES; R E MASON; L L PIPER; B FORT; G PFEIFER; D LYNAM

2001-01-01

313

Manganese contamination in Montreal in relation with traffic density  

Microsoft Academic Search

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese used as an additive in unleaded gasoline in Canada since 1977. Moreover, Canada is the only country in the world to have authorized the replacement of lead alkyls by MMT in gasoline. The purpose of the present study is to assess the importance of air contamination by Mn in relation

Sylvain Loranger; Joseph Zayed; Eric Forget

1994-01-01

314

Colloidal iron and manganese in water affecting RO operation  

Microsoft Academic Search

The finding of various forms of iron, and less commonly of manganese, in numerous reverse osmosis (RO) membrane autopsies we have performed, have led us to call attention to the diverse forms of iron and manganese species in natural waters. Correlation of elemental composition analyses of foulants with contaminants in RO feedwater and pretreatment steps led to successful solutions of

Robert Y. Ning

2009-01-01

315

Pentacoordinated manganese(III) dihydrosalen complexes as biomimetic oxidation catalysts  

Microsoft Academic Search

A series of seven chiral pentadentate dihydrosalen ligands, carrying an imidazole group as a fifth, axial donor was synthesized in racemic and enantiomerically pure form. All of these ligands afforded mononuclear manganese(III) complexes in good yields. In two cases, the pentacoordination of the manganese ion could be confirmed by X-ray crystallography. The complexes catalyzed the epoxidation of olefins with a

A. Berkessel; M. Frauenkron; T. Schwenkreis; A. Steinmetz; G. Baum; D. Fenske

1996-01-01

316

Manganese-aided lime clarification of municipal wastewater  

Microsoft Academic Search

A preliminary study was carried out to assess the usefulness of manganese as an aid in the lime clarification of municipal wastewater. The approach was intended to take advantage of the potential sorption ability of manganese oxides for organic matter in the presence of divalent cations. In a batch clarification test, 9495% and 7577% reduction in turbidity and chemical oxygen

Praveen Kumar Goel; Malay Chaudhuri

1996-01-01

317

75 FR 6631 - Stainless Steel Sheet and Strip in Coils from Japan: Final Results of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013

...between 1.15 and 1.35 percent molybdenum, and between 0.20 and 0.80 percent...nickel. Carbon, manganese, silicon and molybdenum each comprise, by weight, 0.05 percent...by weight, 0.5 to 0.7 percent of molybdenum. The steel also contains, by...

2010-02-10

318

NON-EQUILIBRIUM CHEMISTRY OF DYNAMICALLY EVOLVING PRESTELLAR CORES. I. BASIC MAGNETIC AND NON-MAGNETIC MODELS AND PARAMETER STUDIES  

SciTech Connect

We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores and investigate the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of initial magnetic support, and non-magnetic cores, with varying collapse delay times. We explore, through a parameter study, the competing effects of various model parameters in the evolving molecular abundances, including the elemental C/O ratio, the temperature, and the cosmic-ray ionization rate. We find that different models show their largest quantitative differences at the center of the core, whereas the outer layers, which evolve slower, have abundances which are severely degenerate among different dynamical models. There is a large range of possible abundance values for different models at a fixed evolutionary stage (central density), which demonstrates the large potential of chemical differentiation in prestellar cores. However, degeneracies among different models, compounded with uncertainties induced by other model parameters, make it difficult to discriminate among dynamical models. To address these difficulties, we identify abundance ratios between particular molecules, the measurement of which would have maximal potential for discrimination among the different models examined here. In particular, we find that the ratios between NH{sub 3} and CO, NH{sub 2} and CO, and NH{sub 3} and HCO{sup +} are sensitive to the evolutionary timescale, and that the ratio between HCN and OH is sensitive to the C/O ratio. Finally, we demonstrate that measurements of the central deviation (central depletion or enhancement) of abundances of certain molecules are good indicators of the dynamics of the core.

Tassis, Konstantinos; Willacy, Karen; Yorke, Harold W.; Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-07-01

319

Iron and Manganese in Potable Water  

E-print Network

in nitric acid solution free from chlorides, is first treated with 3odium "bismuthate, "boiled until the color of manganic acid has arisen to a maximum and tben disappeared. By this means all organic matter is ox idized. The solution is then clearified... is used in that no filtration is necessary if the water has been freed from chloride. Methods. Sufficient amount of water to give one to five mil ligrams of Manganese is evaporated with five cubic centi meters of concentrated sulphuric acid until...

Young, Clifford Caudy

1911-06-01

320

Oxidation state of marine manganese nodules  

USGS Publications Warehouse

Analyses of the bulk oxidation state of marine manganese nodules indicates that more than 98% of the Mn in deep ocean nodules is present as Mn(IV). The samples were collected from three quite different areas: the hemipelagic environment of the Guatemala Basin, the pelagic area of the North Pacific, and seamounts in the central Pacific. Results of the study suggest that todorokite in marine nodules is fully oxidized and has the following stoichiometry: (K, Na, Ca, Ba).33(Mg, Cu, Ni).76Mn5O22(H2O)3.2. ?? 1984.

Piper, D.Z.; Basler, J.R.; Bischoff, J.L.

1984-01-01

321

Preparation of highly efficient manganese catalase mimics.  

PubMed

The series of compounds [Mn(bpia)(mu-OAc)](2)(ClO(4))(2) (1), [Mn(2)(bpia)(2)(muO)(mu-OAc)](ClO(4))(3).CH(3)CN (2), [Mn(bpia)(mu-O)](2)(ClO(4))(2)(PF(6)).2CH(3)CN (3), [Mn(bpia)(Cl)(2)](ClO)(4) (4), and [(Mn(bpia)(Cl))(2)(mu-O)](ClO(4))(2).2CH(3)CN (5) (bpia = bis(picolyl)(N-methylimidazol-2-yl)amine) represents a structural, spectroscopic, and functional model system for manganese catalases. Compounds 3 and 5 have been synthesized from 2 via bulk electrolysis and ligand exchange, respectively. All complexes have been structurally characterized by X-ray crystallography and by UV-vis and EPR spectroscopies. The different bridging ligands including the rare mono-mu-oxo and mono-mu-oxo-mono-mu-carboxylato motifs lead to a variation of the Mn-Mn separation across the four binuclear compounds of 1.50 A (Mn(2)(II,II) = 4.128 A, Mn(2)(III,III) = 3.5326 and 3.2533 A, Mn(2)(III,IV) = 2.624 A). Complexes 1, 2, and 3 are mimics for the Mn(2)(II,II), the Mn(2)(III,III), and the Mn(2)(III,IV) oxidation states of the native enzyme. UV-vis spectra of these compounds show similarities to those of the corresponding oxidation states of manganese catalase from Thermus thermophilus and Lactobacillus plantarum. Compound 2 exhibits a rare example of a Jahn-Teller compression. While complexes 1 and 3 are efficient catalysts for the disproportionation of hydrogen peroxide and contain an N(4)O(2) donor set, 4 and 5 show no catalase activity. These complexes have an N(4)Cl(2) and N(4)OCl donor set, respectively, and serve as mimics for halide inhibited manganese catalases. Cyclovoltammetric data show that the substitution of oxygen donor atoms with chloride causes a shift of redox potentials to more positive values. To our knowledge, complex 1 is the most efficient binuclear functional manganese catalase mimic exhibiting saturation kinetics to date. PMID:12377052

Triller, Michael U; Hsieh, Wen-Yuan; Pecoraro, Vincent L; Rompel, Annette; Krebs, Bernt

2002-10-21

322

Thermochemistry of iron manganese oxide spinels  

Microsoft Academic Search

Oxide melt solution calorimetry has been performed on iron manganese oxide spinels prepared at high temperature. The enthalpy of formation of (MnxFe1?x)3O4 at 298K from the oxides, tetragonal Mn3O4 (hausmannite) and cubic Fe3O4 (magnetite), is negative from x=0 to x=0.67 and becomes slightly positive for 0.67

Sophie Guillemet-Fritsch; Alexandra. Navrotsky; Philippe Tailhades; Herv Coradin; Miaojun Wang

2005-01-01

323

Development of Lymantria dispar affected by manganese in food.  

PubMed

We studied the response of gypsy moth (Lymantria dispar (Linnaeus) (Lepidoptera: Lymantriidae)) to the content of manganese in food in the laboratory breeding of caterpillars. The food of the caterpillars {Betula pendula Roth (Fagales: Betulaceae) leaves} was contaminated by dipping in the solution of MnCl2 4H2O with manganese concentrations of 0, 0.5, 5 and 10 mg ml(-1), by which differentiated manganese contents (307; 632; 4,087 and 8,124 mg kg(-1)) were reached. Parameters recorded during the rearing were as follows: effect of manganese on food consumption, mortality and length of the development of caterpillars, pupation and hatching of imagoes. At the same time, manganese concentrations were determined in the offered and unconsumed food, excrements, and exuviae of the caterpillars, pupal cases and imagoes by using the AAS method. As compared with the control, high manganese contents in the food of gypsy moth caterpillars affected the process of development particularly by increased mortality of the first instar caterpillars (8 % mortality for caterpillars with no Mn contamination (T0) and 62 % mortality for subjects with the highest contamination by manganese (T3)), by prolonged development of the first-third instar (18.7 days (T0) and 27.8 days (T3)) and by increased food consumption of the first-third instar {0.185 g of leaf dry matter (T0) and 0.483 g of leaf dry matter (T3)}. The main defence strategy of the caterpillars to prevent contamination by the increased manganese content in food is the translocation of manganese into frass and exuviae castoff in the process of ecdysis. In the process of development, the content of manganese was reduced by excretion in imagoes to 0.5 % of the intake level even at its maximum inputs in food. PMID:25028315

Kula, Emanuel; Martinek, Petr; Chromcov, Lucie; Hedbvn, Josef

2014-10-01

324

Manganese Content of Tradescancia Species Exposed to Automotive Combustion of Methylcyclopentadienyl Manganese Tricarbonyl in Urban and Rural Landscapes  

Microsoft Academic Search

The purpose of this study is to assess the effect of manganese (Mn) from methylcyclopentadienyl manganese tricarbonyl (MMT) on grass (Tradescancia) species beside the major urban and rural highways in the greater Toronto area. Grass clippings were collected at distances up to 40 m from the roadside of a wooded, weakly exposed site (E) and two unwooded, highly exposed sites

Amrit K. Bhuie; Oladele A. Ogunseitan; D. N. Roy

2004-01-01

325

THE STATE OF MANGANESE IN THE PHOTOSYNTHETIC APPARATUS. II. X-RAY ABSORPTION EDGE STUDIES ON MANGANESE IN PHOTOSYNTHETIC MEMBRANES  

SciTech Connect

X-ray absorption spectra at the Manganese K-edge are presented for spinach chloroplasts, and chloroplasts which have been Tris-treated and hence unable to evolve oxygen. A significant change in the electronic environment of manganese is observed and is attributed to the release of manganese from the thylakoid membranes with a concomitant change in oxidation state. A correlation of the K-edge energy, defined as the energy at the first inflection point, with coordination charge has been established for a number of manganese compounds of known structure and oxidation state. Comparison of the manganese K-edge energies of the chloroplast samples with the reference compounds places the average oxidation state of the chloroplasts between +2 and +3. Using the edge spectra for Tris-treated membranes which were osmotically shocked to remove the released manganese, difference edge spectra were synthesized to approximate the active pool of manganese. Coordination charge predictions for this fraction are consistent with an average resting oxidation state higher than +2. The shape at the edge is also indicative of heterogeneity of the manganese site, of low symmetry, or both.

Kirby, J.A.; Goodin, D.B.; Wydrzynski, T.; Robertson, A.S.; Klein, M.P.

1980-11-01

326

Lithium-containing manganese dioxide (composite dimensional manganese oxide: CDMO) as positive material for a lithium secondary battery  

NASA Astrophysics Data System (ADS)

Lithium-containing manganese dioxide (CDMO) has been developed as the positive material for lithium secondary batteries. CDMO is prepared from lithium salt and manganese dioxide by heat treatment. It is a composite oxide of ?/?-MnO 2 and Li 2MnO 3. The influence on rechargeability of lithium salts, heat-treatment temperature, and manganese dioxide type has been investigated by conducting cycle tests with flat cells. Lithium hydroxide is more reactive with MnO 2 in the production of Li 2MnO 3 than either Li 2O or Li 2CO 3. The optimum condition for preparing CDMO is to heat treat LiOH and MnO 2 at about 375 C. CDMO prepared from EMD (electrolytic manganese dioxide) yields a larger and more stable capacity than CDMO prepared from CMD (chemical manganese dioxide). Sodium-free EMD exhibits the largest discharge capacity.

Nohma, T.; Yamamoto, Y.; Nishio, K.; Nakane, I.; Furukawa, N.

327

Solution-based synthesis of manganese oxide cathodes for lithium batteries  

Microsoft Academic Search

With an objective to overcome the cyclability problems of manganese oxides, solution-based procedures are pursued to synthesize metastable manganese oxides. Reduction of permanganate with lithium iodide in an acetonitrile medium followed by heating at 250 C in vacuum gives an amorphous lithium sodium manganese oxyiodide that is intimately mixed with crystalline NaIO. On the other hand, oxidation of manganese acetate

A. Manthiram; J. Kim; S. Choi

2000-01-01

328

Anthracene-Induced Turnover Enhancement in the Manganese Porphyrin-Catalyzed Epoxidation of Olefins  

E-print Network

Anthracene-Induced Turnover Enhancement in the Manganese Porphyrin-Catalyzed Epoxidation of Olefins of the manganese porphyrin. Introduction We have been exploring the notion that reversible supra- molecular complex) catalyzed by achiral manganese porphyrins and by optically active manganese(salicyl)diamine complexes

329

Effect of enhanced manganese oxidation in the hyporheic zone on basin-scale geochemical mass balance  

Microsoft Academic Search

We determined the role of the hyporheic zone (the subsurface zone where stream water and shallow groundwater mix) in enhancing microbially mediated oxidation of dissolved manganese (to form manganese precipitates) in a drainage basin contaminated by copper mining. The fate of manganese is of overall importance to water quality in Pinal Creek Basin, Arizona, because manganese reactions affect the transport

Judson W. Harvey; Christopher C. Fuller

1998-01-01

330

Effect of enhanced manganese oxidation in the hyporheic zone on basin-scale geochemical mass balance  

E-print Network

Effect of enhanced manganese oxidation in the hyporheic zone on basin-scale geochemical mass) in enhancing microbially mediated oxidation of dissolved manganese (to form manganese precipitates) in a drainage basin contaminated by copper mining. The fate of manganese is of overall importance to water

331

Rates of manganese oxidation in aqueous systems  

USGS Publications Warehouse

The rate of crystal growth of Mn3O4 (hausmannite) and ??MnOOH (feitknechtite) in aerated aqueous manganous perchlorate systems, near 0.01 M in total manganese, was determined at pH levels ranging from 7.00 to 9.00 and at temperatures from 0.5 to 37.4??C. The process is autocatalytic, but becomes psuedo first-order in dissolved Mn2+ activity when the amount of precipitate surface is large compared to the amount of unreacted manganese. Reaction rates determined by titrations using an automated pH-stat were fitted to an equation for precipitate growth. The rates are proportional to surface area of oxide and degree of supersaturation with respect to Mn2+. The oxide obtained at the higher temperature was Mn3O4, but at 0.5?? C only ??MnOOH was formed. At intermediate temperatures, mixtures of these solids were formed. The rate of precipitation of hausmannite is strongly influenced by temperature, and that of feitknechtite much less so. The difference in activation energy may be related to differences in crystal structure of the oxides and the geometry of polymeric hydroxy ion precursors. ?? 1981.

Hem, J.D.

1981-01-01

332

Environmental fate of methylcyclopentadienyl manganese tricarbonyl  

SciTech Connect

Methylcyclopentadienyl manganese tricarbonyl (MMT) has been proposed as an octane booster for unleaded gasoline; such use could result in ecological and human exposure through surface water and groundwater ecosystems. To evaluate the environmental risks from MMT, its environmental fate constants and transformation pathways must be known. Constants for physical parameters that would likely influence MMT fate were collected from the literature or calculated; the compound`s octanol/water partition coefficient and water solubility were determined in the laboratory. Experiments were designed to screen MMT for transformation pathways that are significant over environmentally short time frames. The MMT was found to be fairly stable in the dark in aquifer materials and sediments at various Eh levels; half-lives ranged from 0.2 to 1.5 years in aquifer materials at 25 C. (These matrices were not optimized for biodegradation.) On the other hand, MMT photolyzes rapidly in distilled water; its half-life in midday sunlight in water is approximately 1 min and the disappearance quantum yield is 0.13. Photodegradation products were identified as cyclopentadiene, methyl cyclopentadiene, carbon monoxide, and a manganese carbonyl that readily oxidized to trimanganese tetroxide.

Garrison, A.W.; Wolfe, N.L.; Swank, R.R. Jr. [Environmental Protection Agency, Athens, GA (United States). Environmental Research Lab.; Cipollone, M.G. [Technology Applications, Inc., Athens, GA (United States)

1995-11-01

333

Amphiphilic pentaazamacrocyclic manganese superoxide dismutase mimetics.  

PubMed

Five newly functionalized pentaazamacrocyclic manganese complexes, with variable lengths and amounts of the aliphatic groups (three compounds with one linear chain containing 12, 16, and 22 carbon atoms, i.e., MnL1, MnL2, and MnL3, respectively, as well as two compounds containing two C12 and C16 chains, MnL4 and MnL5, respectively) that are derivatives of the known SOD mimetic, Mn(Me2-Pyane), have been synthesized. These amphiphilic complexes were characterized by the ESI mass spectrometry, potentiometric titrations, light scattering, cyclic voltammetry, and direct stopped-flow determination of their SOD activity at pH 8.1 and 7.4 (in phosphate and HEPES buffers). The formation of supramolecular aggregates that predominantly exist in the solution as a defined micellar/nanostructure assembly, with an average 400 nm size, has been demonstrated for MnL1. The biological effects of the selected complexes (MnL1 and MnL2) on the superoxide level in cytosol and mitochondria have been tested, as well as their effects on the prevention of the lipid peroxidation induced by paraquat. Advantages and disadvantages of the lipophilic pentaazamacrocyclic manganese SOD mimetics in comparison to the corresponding nonsubstituted SOD active complex have been discussed. PMID:24369718

Lieb, Dominik; Kenkell, Isabell; Miljkovi?, Jan Lj; Moldenhauer, Daniel; Weber, Nadine; Filipovi?, Milos R; Grhn, Franziska; Ivanovi?-Burmazovi?, Ivana

2014-01-21

334

The cosmic origin of carbon and manganese  

E-print Network

[ABRIDGED] We have determined carbon abundances for 51 dwarf stars and manganese abundances for 95 dwarf stars in two distinct and well defined stellar populations - the Galactic thin and thick disks. As these two populations have different chemical histories we have been able to, through a differential abundance analysis using high-resolution spectra, constrain the formation sites for carbon and manganese in the Galactic disk(s). The analysis of carbon is based on the forbidden [C I] line at 872.7 nm which is an abundance indicator that is insensitive to errors in the stellar atmosphere parameters. Combining these data with our previously published oxygen abundances, based on the forbidden [O I] line at 630.0 nm, we can form very robust [C/O] ratios that we then used to investigate the origin of carbon and the chemical evolution of the Galactic thin and thick disks..... Our interpretation of our abundance trends is that the sources that are responsible for the carbon enrichment in the Galactic thin and thick...

Bensby, Thomas

2008-01-01

335

AmiiSteele  

Cancer.gov

Skip to Main Content Headlines Pediatric Oncology Branch Home > Pediatric Psycho-Oncology Professionals > Profiles > Amii Steele Headline Title Pediatric Psycho-Oncology Professionals Amii Corbisiero Steele Amii Steele First Name:Amii Last Name:

336

Experimental Analysis and Modelling of Fe-Mn-Al-C Duplex Steel Mechanical Behaviour  

SciTech Connect

A new variety of duplex steels with high content of manganese and aluminum has been elaborated in Arcelor Research. These steels contain two phases: austenite and ferrite combining the best features of austenitic and ferritic steels. In this work, four duplex steels with different chemical composition and phase volume fraction are studied. The evolution of internal stresses for the two phases has been determined by X-ray diffraction during an in situ tensile test. These measurements results were used to determine the mechanical behaviour of the duplex steel using a micromechanical approach by scale transition for tensile tests. Though a good agreement between experiments and simulations is found at the macroscopic level, the calculated internal stresses of the austenitic phase do not match experimental results. These discrepancies are attributed to (i) a bad estimation of the austenite yield stress or (ii) the presence of kinematic hardening in the austenitic phase. A new step is then proposed to test these two hypotheses.

Shiekhelsouk, M. N.; Favier, V.; Cherkaoui, M. [LPMM, ENSAM Metz, 4 rue Augustin Fresnel, Technopole, 57078 Metz Cedex 3 (France); Inal, K. [MECASURF, ENSAM Aix, 2 cours des Arts et Metiers, 13617 Aix en Provence (France); Bouaziz, O. [ARCELOR RESEARCH, Voie Romaine, BP 30320, F-57283 Maiziere les Metz Cedex (France)

2007-04-07

337

BRIEF NOTES THE EFFECT OF MANGANESE DEFICIENCY STRUCTURE OF SPINACH CHLOROPLASTS ON THE  

E-print Network

Manganese is involved in the photosynthetic reactions of algae and leaves of higher plants (1-3). In tomato, manganese deficiency results in chloroplasts with a greatly reduced Hill reaction activity per unit chlorophyll (3). In spinach, manganese deficiency causes a 50 to 70 per cent reduction in the FMN-mediated photophosphorylation of isolated chloroplasts but only slightly affects the phosphorylation mediated by pyocyanine (4). Manganese is a constituent of the chloroplasts of higher plants. Photochemical activity of isolated chloroplasts is closely correlated with manganese content, and the manganese important in these reactions is not free ionic manganese but that bound within the chloroplast (5).

F. V. Mercer; Maret Nittim; J. V. Possingham; From Joint; Plant Physiology Unit

338

Steel Recycling Institute (SRI)  

NSDL National Science Digital Library

The Steel Recycling Institute (SRI) provides information and statistics on steel recycling; it was founded by a group of steel companies and the American Iron and Steel Institute (AISI). Originally a grassroots effort focused only on the recycling of steel cans, the SRI now promotes the recycling of all steel products. The SRI homepage provides online access to its three publications, The Dockside Recycler, The Recycling Magnet, and The Appliance Recycler. Recycling information is divided into four categories: cans, cars, appliances, and construction material. Users can use the recycling database to find the nearest steel recycling location. Links provides a large list of both commercial and non-commercial steel sites.

1998-01-01

339

A photometric study of chemically peculiar stars with the STEREO satellites - II. Non-magnetic chemically peculiar stars  

NASA Astrophysics Data System (ADS)

We have analysed the photometric data obtained with the STEREO spacecraft for 558 non-magnetic chemically peculiar (CP) stars to search for rotational and pulsational variability. Applying the Lomb-Scargle and the phase dispersion minimization methods, we have detected photometric variability for 44 objects from which 35 were previously unknown. The new objects are all bright stars on the ecliptic plane (magnitude range 4.7 < V < 11.7) and will therefore be of great interest to studies of stellar structure and evolution. In particular, several show multiple signals consistent with hybrid ? Scuti and ? Doradus pulsation, with different periodicities allowing very different regions of the stellar interior to be studied. There are two subgroups of stars in our sample: the cool metallic line Am (CP1) and the hot HgMn (CP3) stars. These objects fall well inside the classical instability strip where ? Scuti, ? Doradus and slowly pulsating B-type stars are located. We also expect to find periods correlated to the orbital period for CP1 objects as they are mostly members of binary systems. For CP3 stars, rotationally induced variability is still a matter of debate. Although surface spots were detected, they are believed to produce only marginal photometric amplitudes. So, periods from several hours to a few days were expected for these two star groups. The STEREO/HI-1 data are well matched to studies of this frequency domain, owing to the cadence of approximately 40 min and multiple epochs over four and a half years. The remaining 514 stars are likely to be constant in the investigated range from 0.1 to 10 d. In some cases, the presence of blending or systematic effects prevented us from detecting any reliable variability and in those cases we classified the star as constant. We discuss our results in comparison to already published ones and find a very good agreement. Finally, we have calibrated the variable stars in terms of the effective temperature and luminosity in order to estimate masses and ages. For this purpose, we used specifically developed calibrations for CP stars and, when available, Hipparcos parallaxes. All but two objects cover the stellar mass range from 1.5 to 5 M? and are located between the zero- and terminal-age main sequence.

Paunzen, E.; Wraight, K. T.; Fossati, L.; Netopil, M.; White, G. J.; Bewsher, D.

2013-02-01

340

Thermal chemistry of Mn{sub 2}(CO){sub 10} during deposition of thin manganese films on silicon oxide and on copper surfaces  

SciTech Connect

The surface chemistry of dimanganese decacarbonyl on the native oxide of Si(100) wafers was characterized with the aid of x-ray photoelectron spectroscopy. Initial experiments in a small stainless-steel reactor identified a narrow range of temperatures, between approximately 445 and 465 K, in which the deposition of manganese could be achieved in a self-limiting fashion, as is desirable for atomic layer deposition. Deposition at higher temperatures leads to multilayer growth, but the extent of this Mn deposition reverses at even higher temperatures (about 625 K), and also ifhydrogen is added to the reaction mixture. Extensive decarbonylation takes place below room temperature, but limited C-O bond dissociation and carbon deposition are still seen after high exposures at 625 K. The films deposited at low ({approx}450 K) temperatures are mostly in the form of MnO, but at 625 K that converts to a manganese silicate, and upon higher doses a manganese silicide forms at the SiO{sub 2}/Si(100) interface as well. No metallic manganese could be deposited with this precursor on either silicon dioxide or copper surfaces.

Qin Xiangdong; Sun Huaxing; Zaera, Francisco [Department of Chemistry, University of California, Riverside, California 92521 (United States)

2012-01-15

341

Influence of particle solubility on the delivery of inhaled manganese to the rat brain: manganese sulfate and manganese tetroxide pharmacokinetics following repeated (14-day) exposure.  

PubMed

Dissolution rate can influence the pulmonary clearance of a metal and thus affect its delivery to the brain and other organs. The goal of this study was to determine the exposure-response relationship for the relatively soluble sulfate (MnSO(4)) and insoluble tetroxide (Mn(3)O(4)) forms of inhaled manganese in adult male CD rats. Rats were exposed 6 h/day for 7 days/week (14 exposures) to either MnSO(4) or Mn(3)O(4) at 0, 0.03, 0.3, or 3 mg Mn/m(3). End-of-exposure olfactory bulb, striatum, cerebellum, bile, lung, liver, femur, serum, and testes (n = 6 rats/concentration/chemical) manganese concentrations and whole-body (54)Mn elimination were then determined. Increased whole-body (54)Mn clearance rates were observed in animals from the high-dose (3 mg Mn/m(3)) MnSO(4) and Mn(3)O(4) exposure groups. Elevated manganese concentrations in the lung were observed following MnSO(4) and Mn(3)O(4) exposure to > or=0.3 mg Mn/m(3). Increased olfactory bulb and femur manganese concentrations were also observed following MnSO(4) exposure at > or=0.3 mg Mn/m(3). Elevated striatal, testes, liver, and bile manganese concentrations were observed following exposure to MnSO(4) at 3 mg Mn/m(3). Elevated olfactory bulb, striatal, femur, and bile manganese concentrations were observed following exposure to Mn(3)O(4) at 3 mg Mn/m(3). Animals exposed to MnSO(4) (3 mg Mn/m(3)) had lower lung and higher olfactory bulb and striatal manganese concentrations compared with levels achieved following similar Mn(3)O(4) exposures. Our results suggest that inhalation exposure to soluble forms of manganese results in higher brain manganese concentrations than those achieved following exposure to an insoluble form of manganese. PMID:11162771

Dorman, D C; Struve, M F; James, R A; Marshall, M W; Parkinson, C U; Wong, B A

2001-01-15

342

Influence of manganese on enzyme synthesis and citric acid accumulation in Aspergillus niger  

Microsoft Academic Search

Summary A comparison of citric acid fermentations in manganese-deficient and manganese-containing media showed that manganese strongly influences idiophase metabolism. In the presence of manganese, cell growth increases, sugar consumption is diminished and acidogenesis decreases drastically. An investigation of the key enzymes of glycolysis, the pentosephosphate pathway, TCA-cycle, nitrogen metabolism, and gluconeogenesis indicated that manganese deficiency was accompanied by a repression

C. P. Kubicek; M. Rhr

1977-01-01

343

Manganese exposure among smelting workers: blood manganese-iron ratio as a novel tool for manganese exposure assessment  

PubMed Central

Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population. PMID:19283519

Cowan, Dallas M.; Fan, Qiyuan; Zou, Yan; Shi, Xiujuan; Chen, Jian; Aschner, Michael; Rosenthal, Frank S.; Zheng, Wei

2014-01-01

344

Reduced Atmospheric Manganese in Montreal Following Removal of Methylcyclopentadienyl Manganese Tricarbonyl (MMT)  

Microsoft Academic Search

Methylcyclopentadienyl manganese tricarbonyl (MMT) was used between 1990 and 2003 as an antiknock agent and as an octane booster\\u000a in Canadian unleaded gasoline. Its combustion leads to Mn emissions. The objective of this research was to examine the variations\\u000a in atmospheric Mn in Montreal (Canada) from 2001 to 2007, covering the period prior (20012003) to and following (20052007)\\u000a MMT use.

Alexandre Joly; Jean Lambert; Claude Gagnon; Greg Kennedy; Donna Mergler; Ariane Adam-Poupart; Joseph Zayed

2011-01-01

345

Environmental contamination and human exposure to manganese contribution of methylcyclopentadienyl manganese tricarbonyl in unleaded gasoline  

Microsoft Academic Search

The organomanganese compound MMT (methylcyclopentadienyl manganese tricarbonyl), an antiknock additive in unleaded gasoline,\\u000a has been used in Canada since 1976. Indeed, Canada is the only country where MMT is almost exclusively used. In October 1995,\\u000a by court decision the Environmental protection Agency (EPA) granted Ethyl's waiver for the use of MMT in the United States.\\u000a Paradoxically, in 1997 the federal

Joseph Zayed; Adolf Vyskocil; Greg Kennedy

1999-01-01

346

Manganese: brain transport and emerging research needs.  

PubMed

Idiopathic Parkinson's disease (IPD) represents a common neurodegenerative disorder. An estimated 2% of the U.S. population, age 65 and older, develops IPD. The number of IPD patients will certainly increase over the next several decades as the baby-boomers gradually step into this high-risk age group, concomitant with the increase in the average life expectancy. While many studies have suggested that industrial chemicals and pesticides may underlie IPD, its etiology remains elusive. Among the toxic metals, the relationship between manganese intoxication and IPD has long been recognized. The neurological signs of manganism have received close attention because they resemble several clinical disorders collectively described as extrapyramidal motor system dysfunction, and in particular, IPD and dystonia. However, distinct dissimilarities between IPD and manganism are well established, and it remains to be determined whether Mn plays an etiologic role in IPD. It is particularly noteworthy that as a result of a recent court decision, methylcyclopentadienyl Mn tricarbonyl (MMT) is presently available in the United States and Canada for use in fuel, replacing lead as an antiknock additive. The impact of potential long-term exposure to low levels of MMT combustion products that may be present in emissions from automobiles has yet to be fully evaluated. Nevertheless, it should be pointed out that recent studies with various environmental modeling approaches in the Montreal metropolitan (where MMT has been used for more than 10 years) suggest that airborne Mn levels were quite similar to those in areas where MMT was not used. These studies also show that Mn is emitted from the tail pipe of motor vehicles primarily as a mixture of manganese phosphate and manganese sulfate. This brief review characterizes the Mn speciation in the blood and the transport kinetics of Mn into the central nervous system, a critical step in the accumulation of Mn within the brain, outlines the potential susceptibility of selected populations (e.g., iron-deficient) to Mn exposure, and addresses future research needs for Mn. PMID:10852840

Aschner, M

2000-06-01

347

Manganese abundances in Galactic bulge red giants  

NASA Astrophysics Data System (ADS)

Context. Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut between the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. Aims: The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. Methods: High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. Results: We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Galactic bulge. We find [Mn/Fe] ~ -0.7 at [Fe/H] ~ -1.3, increasing to a solar value at metallicities close to solar, and showing a spread around - 0.7 ? [Fe/H] ? -0.2, in good agreement with other work on Mn in bulge stars. There is also good agreement with chemical evolution models. We find no clear difference in the behaviour of the four bulge fields. Whereas [Mn/Fe] vs. [Fe/H] could be identified with the behaviour of the thick disc stars, [Mn/O] vs. [O/H] has a behaviour running parallel, at higher metallicities, compared to thick disc stars, indicating that the bulge enrichment might have proceeded differently from that of the thick disc. Observations collected at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Tables 1-6 and Figs. 1-6 are available in electronic form at http://www.aanda.org

Barbuy, B.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gmez, A.; Trevisan, M.; Dutra, N.

2013-11-01

348

Airborne manganese particulates and methylcyclopentadienyl manganese tricarbonyl (MMT) at selected outdoor sites in Montreal.  

PubMed

This study aims to assess the atmospheric concentrations of methylcyclopentadienyl manganese tricarbonyl (MMT), respirable manganese (MNR) and total manganese (MnT) in certain specific microenvironments and to provide an estimation of human exposure to MnR. Sampling was carried out in five microenvironments: a gas station, an underground car park, downtown Montreal, near an expressway and near an oil refinery. The samples were collected using Gil-Air portable pumps during three days and were analyzed by instrumental neutron activation analysis (INAA). The mean concentrations of MnR, MnT and MMT were 0.036 microgram m-3, 0.103 microgram m-3 and 0.005 microgram m-3 respectively. The MnR/MnT ratios vary from 25% to 43% (mean 35%) while the MMT/MnT ratios averaged about 5%. Furthermore, the mean concentration of the MnR measured near the expressway (0.053 microgram m-3) is similar to the United States Environmental Protection Agency (U.S. EPA) reference concentration (RfC = 0.05 microgram m-3). The average daily environmental exposure dose to MNR is estimated at 0.010 microgram kg-1 d-1 and its contribution to the multimedia exposure (air, food and water) is low. The overall results show a lack of potential exposure to MMT and substantial concentrations of MnR near an expressway. PMID:10385879

Zayed, J; Thibault, C; Gareau, L; Kennedy, G

1999-01-01

349

Isotopic evidence for organic matter oxidation by manganese reduction in the formation of stratiform manganese carbonate ore  

USGS Publications Warehouse

Unlike other marine-sedimentary manganese ore deposits, which are largely composed of manganese oxides, the primary ore at Molango (Hidalgo State, Mexico) is exclusively manganese carbonate (rhodochrosite, Mn-calcite, kutnahorite). Stable isotope studies of the carbonates from Molango provide critical new information relevant to the controversy over syngenetic and diagenetic models of stratiform manganese deposit formation. Negative ??13C values for carbonates from mineralized zones at Molango are strongly correlated with manganese content both on a whole rock scale and by mineral species. Whole rock ??13C data fall into three groups: high-grade ore = -16.4 to -11.5%.; manganese-rich, sub-ore-grade = -5.2 to 0%.; and unmineralized carbonates = 0 to +2.5%. (PDB). ??18O data show considerable overlap in values among the three groups: +4.8 to -2.8, -5.4 to -0.3%., and -7.4 to +6.2 (PDB), respectively. Isotopic data for individual co-existing minerals suggest a similar separation of ??13C values: ??13C values from calcite range from -1.1 to +0.7%. (PDB), whereas values from rhodochrosite are very negative, -12.9 to -5.5%., and values from kutnahorite or Mn-calcite are intermediate between calcite and rhodochrosite. 13C data are interpreted to indicate that calcite (i.e. unmineralized carbonate) formed from a normal marine carbon reservoir. However, 13C data for the manganese-bearing carbonates suggest a mixed seawater and organic source of carbon. The presence of only trace amounts of pyrite suggests sulfate reduction may have played a minor part in oxidizing organic matter. It is possible that manganese reduction was the predominant reaction that oxidized organic matter and that it released organic-derived CO2 to produce negative ??13C values and manganese carbonate mineralization. ?? 1988.

Okita, P.M.; Maynard, J.B.; Spiker, E. C.; Force, E.R.

1988-01-01

350

Manganese Neurotoxicity: a Focus on Glutamate Transporters  

PubMed Central

Manganese (Mn) is an essential element that is required in trace amount for normal growth, development as well maintenance of proper function and regulation of numerous cellular and biochemical reactions. Yet, excessive Mn brain accumulation upon chronic exposure to occupational or environmental sources of this metal may lead to a neurodegenerative disorder known as manganism, which shares similar symptoms with idiopathic Parkinsons disease (PD). In recent years, Mn exposure has gained public health interest for two primary reasons: continuous increased usage of Mn in various industries, and experimental findings on its toxicity, linking it to a number of neurological disorders. Since the first report on manganism nearly two centuries ago, there have been substantial advances in the understanding of mechanisms associated with Mn-induced neurotoxicity. This review will briefly highlight various aspects of Mn neurotoxicity with a focus on the role of astrocytic glutamate transporters in triggering its pathophysiology. PMID:24472696

2013-01-01

351

Impaired Manganese Metabolism Causes Mitotic Misregulation*  

PubMed Central

Manganese is an essential trace element, whose intracellular levels need to be carefully regulated. Mn2+ acts as a cofactor for many enzymes and excess of Mn2+ is toxic. Alterations in Mn2+ homeostasis affect metabolic functions and mutations in the human Mn2+/Ca2+ transporter ATP2C1 have been linked to Hailey-Hailey disease. By deletion of the yeast orthologue PMR1 we have studied the impact of Mn2+ on cell cycle progression and show that an excess of cytosolic Mn2+ alters S-phase transit, induces transcriptional up-regulation of cell cycle regulators, bypasses the need for S-phase cell cycle checkpoints and predisposes to genomic instability. On the other hand, we find that depletion of the Golgi Mn2+ pool requires a functional morphology checkpoint to avoid the formation of polyploid cells. PMID:22493290

Garcia-Rodriguez, Nestor; Diaz de la Loza, Maria del Carmen; Andreson, Bethany; Monje-Casas, Fernando; Rothstein, Rodney; Wellinger, Ralf Erik

2012-01-01

352

Neuropsychological Motor Outcomes in Adults from Airborne Manganese Exposure  

EPA Science Inventory

Background: The literature on manganese (Mn) is dominated by occupational exposures of adults exposed often to high levels without protection. Neuropsychological adverse health effects are similar to Parkinsons Disease with psychomotor slowing, tremor, cognitive and mood ...

353

Manganese Based Oxidative Technologies For Water/Wastewater Treatment  

E-print Network

and structural properties of ferrites. These laboratory prepared catalysts were thoroughly characterized using XRD, SEM, TEM, HR-TEM, and BET. Their magnetic properties have also been studied. These manganese ferrites offer the potential to enhance hydroxyl...

Desai, Ishan

2013-08-27

354

Effects of alloying elements and microstructure on the susceptibility of the welded HSLA steel to hydrogen-induced cracking and sulfide stress cracking  

Microsoft Academic Search

Hydrogen-induced cracking (HIC) and sulfide stress cracking (SSC) susceptibility of the submerged arc welded API 5L-X70 pipeline steel with different amounts of titanium at two levels of manganese (1.4% and 2%) were studied. The centerline segregation region (CSR) observed in the X70 pipe steel played an important role in the HIC susceptibility. Increased acicular ferrite content in the microstructure improved

B. Beidokhti; A. Dolati; A. H. Koukabi

2009-01-01

355

[Occupational neurotoxicology due to heavy metals-especially manganese poisoning].  

PubMed

The most hazardous manganese exposures occur in mining and smelting of ore. Recently, the poisoning has been frequently reported to be associated with welding. In occupational exposure, manganese is absorbed mainly by inhalation. Manganese preferentially accumulates in tissues rich in mitochondria. It also penetrates the blood brain barrior and accumulate in the basal ganglia, especially the globus pallidus, but also the striatum. Manganese poisoning is clinically characterized by the central nervous system involvement including psychiatric symptomes, extrapyramidal signs, and less frequently other neurological manifestations, Psychiatric symptomes are well described in the manganese miners and incrude sleep disturbance, disorientation, emotional lability, compulsive acts, hallucinations, illusions, and delusions. The main characteristic manifestations usually begin shortly after the appearance of these psychiatric symptomes. The latter neurological signs are progressive bradykinesia, dystonia, and disturbance of gait. Bradykinesia is one of the most important findings. There is a remarkable slowing of both active and passive movements of the extremities. Micrographia is frequently observed and a characteristic finding. The patients may show some symmetrical tremor, which usually not so marked. The dystonic posture of the limbs is often accompanied by painfull cramps. This attitudal hypertonia has a tenndency to decrease or disappear in the supine position and to increase in orthostation. Cog-wheel rigidity is also elisited on the passive movement of all extremities. Gait disturbance is also characteristic in this poisoning. In the severe cases, cook gait has been reported. The patient uses small steps, but has a tendency to elevate the heels and to rotate them outward. He progress without pressing on the flat of his feet, but only upon the metatarsophalangeal articulations, mainly of the fourth and fifth toes. Increased signal in T1-weighted image in the basal ganglia has been reported in patients with the poisoning. Thus, increasd signal intensities as a target site dose can be a more useful biomakers of the manganese than other biological indicies such as ambient manganese concentration or blood manganese concentration on individual basis. Manganese poisoning ultimately becomes chronic. However, if the disease is diagnosed while still at the early stages and the patient is removed from exposure, the course may be reversed. Once well established, it becomes progressive and irreversible, even when exposure is terminated. Levodopa therapy is not effective for the management of manganese poisoning. Levodopa unresponsiveness may be usefull to distinguish manganese-induced parkinsonism from Parkinson disease. PMID:17585589

Inoue, Naohide

2007-06-01

356

Surface nanocrystallization of 310S stainless steel and its effect on oxidation behavior  

SciTech Connect

Two techniques, unbalanced magnetron sputter deposition and high-energy short-pulsed plasma discharge, have been used to produce a nanocrystalline surface on AISI 310S stainless steel specimens. The average grain size after surface modification was estimated as {approximately} 100 nm by using atomic force microscopy. Cyclic oxidation was performed at 1,000 C with treated and untreated 310S stainless steel specimens. The oxide products formed on the specimens consisted of an outer spinel layer that was rich in chromium, iron, manganese, and nickel, and an inner chromium-rich layer. It was found that the concentrations of iron and manganese in the outer layer of treated specimens were higher, and adherence of the scale was better in the treated specimens. The observed oxidation behavior can be explained by the increase of the creep diffusion rate in the fine oxide scale formed on the nanocrystalline surfaces.

Liu, Z.; He, Y.; Gao, W. [Univ. of Auckland (New Zealand). Dept. of Chemical and Materials Engineering] [Univ. of Auckland (New Zealand). Dept. of Chemical and Materials Engineering

1998-02-01

357

Occupational and Environmental Exposure of Garage Workers and Taxi Drivers to Airborne Manganese Arising from the Use of Methylcyclopentadienyl Manganese Tricarbonyl in Unleaded Gasoline  

Microsoft Academic Search

Occupational and environmental exposure to airborne manganese has been measured for two groups of workers in Montreal, taxi drivers and garage mechanics. In Canada methylcyclopentadienyl manganese tricarbonyl (MMT) has replaced lead as an anti-knock agent in gasoline and represents a potentially important source of manganese contamination for the population in general and for the two chosen groups of workers in

J. Zayed; M. Grin; S. Loranger; P. Sierra; D. Bgin; G. Kennedy

1994-01-01

358

The thermal stability of lithium-manganese-oxide spinel phases  

Microsoft Academic Search

The thermal stability of stoichiometric spinel phases in the system Li1+?Mn2-?O4 (0 ? ? ? 0.33) has been investigated by high-temperature powder X-ray diffraction, differential thermal analysis, and thermogravimetric analysis. At elevated temperatures, the lithium-manganese-oxide spinels undergo phase changes by loss of oxygen and lithia (Li2O). The data highlight the importance of temperature control when synthesising lithium-manganese-oxide spinel compounds.

M. M. Thackeray; M. F. Mansuetto; D. W. Dees; D. R. Vissers

1996-01-01

359

Spinel lithium manganese oxide synthesized under a pressurized oxygen atmosphere  

Microsoft Academic Search

Spinel lithium manganese oxide was synthesized via co-precipitation. The prepared lithium manganese oxide powder was further heated at 700C for 15h under pressurized (3bar) oxygen atmosphere. The resultant exhibited a highly crystalline cubic spinel phase with space group Fd3m, as confirmed by X-ray diffraction. The spinel compound exhibited a slightly smaller lattice constant than a conventional spinel compound, even though

Ki-Soo Lee; Seung-Taek Myung; Hun-Gi Jung; Jung Kyoo Lee; Yang-Kook Sun

2010-01-01

360

Laser microstructuring and annealing processes for lithium manganese oxide cathodes  

Microsoft Academic Search

It is expected that cathodes for lithium-ion batteries (LIB) composed out of nano-composite materials lead to an increase in power density of the LIB due to large electrochemically active surface areas but cathodes made of lithium manganese oxides (LiMnO) suffer from structural instabilities due to their sensitivity to the average manganese oxidation state. Therefore, thin films in the LiMnO system

J. Prll; R. Kohler; M. Torge; S. Ulrich; C. Ziebert; M. Bruns; H. J. Seifert; W. Pfleging

2011-01-01

361

Genotypic Variation of Manganese Toxicity and Tolerance of Japanese Mint  

Microsoft Academic Search

Plantlets of Japanese mint (Mentha arvensis L., cv. MASI and Hybrid-77) were grown on nutrient solutions containing manganese. For cv. MASI, dry weight of plant tops grown in 0.1 and 1.0 ug Mn\\/ml solutions was higher than that of plants growing in solution without manganese. In contrast, dry weight of plant tops of cv. Hybrid-77 had only a slight increase

A. Misra

1997-01-01

362

Mineralogical Characterization of Manganese Oxides in Mine Water Treatment Systems  

NASA Astrophysics Data System (ADS)

The removal of manganese(II) from mine water is a significant problem for both operating and abandoned mines across the United States. In many situations, manganese removal represents the most costly aspect of mine water treatment. Active treatment of Mn-containing mine water requires adjustment of pH to 9-10, and results in the abiotic precipitation of manganese oxides (MnOx). After manganese removal, this high pH water must be neutralized before release. Alternatively, passive limestone beds can be used for neutralization of low-pH mine water and subsequent manganese removal. Although limestone beds are effective for Mn removal, the processes involved are not clear (e.g., relative importance of biological Mn(II) oxidation versus surface mediated oxidation) and the characteristics of the manganese "crusts" formed are not well studied. In this field-based study, we have collected natural manganese oxides from two different limestone beds designed to treat mine water from abandoned coal strip mines in Pennsylvania. Samples were collected at different locations in the beds and at different seasons to capture possible variations in mineralogical characteristics. Water samples were also collected to measure the corresponding solution chemistry and revealed that manganese removal was strongly temperature dependent. Solid samples have been examined by scanning and transmission electron microscopy, and by X-ray diffraction. Micro-diffraction XRD has been used to tentatively identify disordered buserite as a predominant mineral in many of these crust samples. Additional characterizations will include particle size distribution and surface charge. Synchroton-based X-ray techniques such as scanning transmission X-ray microscopy (STXM) and X-ray spectroscopy (XAS) may also be pursued.

Tan, H.; Heaney, P.; Post, J.; Burgos, W.

2006-05-01

363

Higher valency ion substitution into the manganese oxide framework.  

PubMed

A new route for higher valency ion substitution into the manganese oxide (OMS-2) framework is reported. Isomorphously substituted vanadium and niobium OMS-2 were hydrothermally synthesized at 200 degrees C for a period of 2 days. Characterization by XRD, elemental analysis, Raman spectroscopy, and resistivity studies proved that vanadium was incorporated into the manganese oxide structure. The presence of vanadium in the framework changes the electrical properties, making the material very attractive for water sensing applications. PMID:15212514

Polverejan, Mihai; Villegas, Josanlet C; Suib, Steven L

2004-06-30

364

Radiation resistant austenitic stainless steel alloys  

DOEpatents

An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01% to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties.

Maziasz, Philip J. (Oak Ridge, TN); Braski, David N. (Oak Ridge, TN); Rowcliffe, Arthur F. (Oak Ridge, TN)

1989-01-01

365

Radiation resistant austenitic stainless steel alloys  

DOEpatents

An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01 to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties. 4 figs.

Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.

1987-02-11

366

Magnesium-dependent processes are targets of bacterial manganese toxicity.  

PubMed

A Bradyrhizobium japonicum mutant defective in the gene encoding the high-affinity Mn(2+) transporter MntH has a severe growth phenotype under manganese limitation. Here, we isolated suppressor mutants of an mntH strain that grew under manganese limitation, and activities of high-affinity Mn(2+) transport and Mn(2+) -dependent enzymes were partially rescued. The suppressor strains harbour gain-of-function mutations in the gene encoding the Mg(2+) channel MgtE. The MgtE variants likely allow Mn(2+) entry via loss of a gating mechanism that normally holds the transporter in the closed state when cellular Mg(2+) levels are high. Both MgtE-dependent and MgtE-independent suppressor phenotypes were recapitulated by magnesium-limited growth of the mntH strain. Growth studies of wild-type cells suggest that manganese is toxic to cells when environmental magnesium is low. Moreover, extracellular manganese and magnesium levels were manipulated to inhibit growth without substantially altering the intracellular content of either metal, implying that manganese toxicity depends on its cellular distribution rather than the absolute concentration. Mg(2+) -dependent enzyme activities were found to be inhibited or stimulated by Mn(2+) . We conclude that Mn(2+) can occupy Mg(2+) binding sites in cells, and suggest that Mg(2+) -dependent processes are targets of manganese toxicity. PMID:24975873

Hohle, Thomas H; O'Brian, Mark R

2014-08-01

367

Low Copper and High Manganese Levels in Prion Protein Plaques  

PubMed Central

Accumulation of aggregates rich in an abnormally folded form of the prion protein characterize the neurodegeneration caused by transmissible spongiform encephalopathies (TSEs). The molecular triggers of plaque formation and neurodegeneration remain unknown, but analyses of TSE-infected brain homogenates and preparations enriched for abnormal prion protein suggest that reduced levels of copper and increased levels of manganese are associated with disease. The objectives of this study were to: (1) assess copper and manganese levels in healthy and TSE-infected Syrian hamster brain homogenates; (2) determine if the distribution of these metals can be mapped in TSE-infected brain tissue using X-ray photoelectron emission microscopy (X-PEEM) with synchrotron radiation; and (3) use X-PEEM to assess the relative amounts of copper and manganese in prion plaques in situ. In agreement with studies of other TSEs and species, we found reduced brain levels of copper and increased levels of manganese associated with disease in our hamster model. We also found that the in situ levels of these metals in brainstem were sufficient to image by X-PEEM. Using immunolabeled prion plaques in directly adjacent tissue sections to identify regions to image by X-PEEM, we found a statistically significant relationship of copper-manganese dysregulation in prion plaques: copper was depleted whereas manganese was enriched. These data provide evidence for prion plaques altering local transition metal distribution in the TSE-infected central nervous system. PMID:23435237

Johnson, Christopher J.; Gilbert, P.U.P.A.; Abrecht, Mike; Baldwin, Katherine L.; Russell, Robin E.; Pedersen, Joel A.; Aiken, Judd M.; McKenzie, Debbie

2013-01-01

368

The cause of welding cracks in aircraft steels  

NASA Technical Reports Server (NTRS)

The discussion in this article refers to gas welding of thin-walled parts of up to about 3 mm thickness. It was proven that by restricting the sulphur, carbon, and phosphorous content, and by electric-furnace production of the steel, it was possible in a short time to remove this defect. Weld hardness - i.e., martensite formation and hardness of the overheated zone - has no connection with the tendency to weld-crack development. Si, Cr, Mo, or V content has no appreciable effect, while increased manganese content tends to reduce the crack susceptibility.

Muller, J

1940-01-01

369

Heat treatment giving a stable high temperature micro-structure in cast austenitic stainless steel  

Microsoft Academic Search

A heat-treated cast austenitic stainless steel alloy consisting essentially of about 13-17% chromium, about 13-17% manganese, about 1.5-2.5% molybdenum, about 1.0-2.0% carbon, about 0.5-15% niobium, about 0.5-1.5% silicon, with the balance being iron is described which is produced by the process comprising: casting the alloy; subjecting the alloy to a prebraze heat cycle treatment including heat treating the cast alloy

D. L. Anton; F. D. Lemkey

1988-01-01

370

Effect of warm working on the precipitation of vanadium carbide in a medium carbon austenitic steel  

Microsoft Academic Search

Electrical resistance measurements and electron microscope observations have been used to interpret the ageing characteristics of a 0.4% carbon-24% manganese-0.7% vanadium steel in the temperature range 550 to 700 C. It has been shown that vanadium carbides form in a diffusion controlled process, activation energy 295 kJ mol-1, producing precipitate densities in the matrix of ~1016 cm-3. The kinetics suggest

S. J. Harris; N. R. Nag

1976-01-01

371

Preliminary studies concerning Hadfield steel behavior during laser beam welding in pulsating regime  

NASA Astrophysics Data System (ADS)

This work proposes to analyze the behavior of austenitic manganese - Hadfield steel during laser beam welding in continuous regime. In order to limit the number of experiments, a 2 4 type factorial experiment was used, with 16 assays, after a frequently used program matrix for these situations. Fusion lines at different service regimes, as well as head to head welds were performed. Microhardness measurements and microstructure modifications that appear as an effect of laser irradiation are also analyzed.

David, Ion; ?erban, Viorel-Aurel

2007-08-01

372

Internal oxidation during case-hardening of steels in endothermic atmospheres  

Microsoft Academic Search

1.Thermodynamic calculations showed that internal oxidation of titanium, manganese, silicon, and chromium is possible during carburization in an endothermic atmosphere.2.One finds internal oxidation in the majority of alloy steels subjected to carburization in an endothermic atmosphere. The outward indication of such oxidation is the formation of a troostite network on the surface to a depth of 0.010.03 mm.Internal oxidation is

I. S. Kozlovskii; A. T. Kalinin; A. Ya. Novikova; E. A. Lebedeva; A. I. Feofanova

1967-01-01

373

THE STATE OF MANGANESE IN THE PHOTOSYNTHETIC APPARATUS: FIRST VIEW OF THE MANGANESE SITES BY X-RAY ABSORPTION SPECTROSCOPY  

SciTech Connect

Manganese atoms have long been implicated as essential ingredients in photosynthetic oxygen evolution. Heretofore they have eluded direct observation. We report the first direct observation, by X-ray Absorption Spectroscopy, of the Mn sites in chloroplasts isolated from Spinacia oleracea. The manganese in chlorplasts is commonly thought to exist in two pools. The major pool, corresponding to two-thirds of the manganese, can be reversibly released with concomitant loss of oxygen evolving capacity, and has thus come to be assigned as the active pool. The role of the remanant one-third, or tightly bound pool is moot. Our analysis of the Extended X-ray Absorption Fine Structure of the active pool is consistent with a bridged dimeric structure involving two manganese atoms separated by about 2.7 {Angstroms}. The distance between manganese and bridging ligands is about 1.8 {Angstrom}. Analysis of the edge region suggests that the manganese in the active pool exists in oxidation states somewhat higher than Mn(II).

Kirby, Jon A.; Goodin, D.B.; Robertson, A.S.; Smith, J.P.; Thompson, A.C.; Klein, M.P.

1980-11-01

374

Glutamate/aspartate transporter (GLAST), taurine transporter and metallothionein mRNA levels are differentially altered in astrocytes exposed to manganese chloride, manganese phosphate or manganese sulfate.  

PubMed

Manganese (Mn)-induced neurotoxicity can occur due to environmental exposure (air pollution, soil, water) and/or metabolic aberrations (decreased biliary excretion). High brain manganese levels lead to oxidative stress, as well as alterations in neurotransmitter metabolism with concurrent neurobehavioral deficits. Based on the few existing studies that have examined brain regional Mn concentration, it is likely that in pathological conditions, Mn concentration can reach between 100 and 500 microM. Environmental Mn exposure as a result of methylcyclopentadienyl manganese tricarbonyl (MMT) combustion is in the form of phosphate or sulfate (MnPO4, MnSO4, respectively). Pharmacokinetic studies have shown that the Mn salt will determine the rate of transport into the brain: MnCl2 > MnSO4 > MnPO4. The salt-specific neurotoxicity of these species is unknown. The primary goal of this study was to examine gene expression of glutamate/aspartate transporter (GLAST), taurine transporter (tau-T), and metallothionein-I (MT-I) in astrocytes exposed to manganese chloride (MnCl2), manganese sulfate (MnSO4), and manganese phosphate (MnPO4). We hypothesized that the effects of MnPO4 and MnSO4 exposure on GLASTexpression in astrocytes would be similar to those induced by MnCl2, since irrespective of salt species exposure, once internalized by astrocytes, the Mn ion would be identically complexed. At the same time, we hypothesized that the magnitude of the effect would be salt-dependent, since the chemical speciation would determine the rate of intracellular uptake of Mn. MnCl2 caused a significant overall decrease (P < 0.0001) in astrocytic GLAST mRNA levels with MnSO4 causing a moderate decrease. MnPO4 exposure did not alter GLAST mRNA in astrocytes. We also sought to examine astrocytic metallothionein and taurine transporter gene expression as markers of manganese exposure. Our findings suggest that manganese chloride significantly decreased (P < 0.0001) astrocytic metallothionein mRNA compared to both the sulfate and phosphate species. However, astrocytic taurine transporter mRNA was not affected by Mn exposure, irrespective of the salt species. These data are consistent with the hypothesis that astrocytic neurotoxicity due to Mn exposure is dependent upon its species, with solubility, and by inference, intracellular concentration, representing a major determinant of its neurotoxicity. PMID:12387356

Erikson, Keith M; Suber, Robert L; Aschner, Michael

2002-09-01

375

Six-coordinate manganese(3+) in catalysis by yeast manganese superoxide dismutase.  

PubMed

Reduction of superoxide (O2-) by manganese-containing superoxide dismutase occurs through either a "prompt protonation" pathway, or an "inner-sphere" pathway, with the latter leading to formation of an observable Mn-peroxo complex. We recently reported that wild-type (WT) manganese superoxide dismutases (MnSODs) from Saccharomyces cerevisiae and Candida albicans are more gated toward the "prompt protonation" pathway than human and bacterial MnSODs and suggested that this could result from small structural changes in the second coordination sphere of manganese. We report here that substitution of a second-sphere residue, Tyr34, by phenylalanine (Y34F) causes the MnSOD from S. cerevisiae to react exclusively through the "inner-sphere" pathway. At neutral pH, we have a surprising observation that protonation of the Mn-peroxo complex in the mutant yeast enzyme occurs through a fast pathway, leading to a putative six-coordinate Mn(3+) species, which actively oxidizes O2- in the catalytic cycle. Upon increasing pH, the fast pathway is gradually replaced by a slow proton-transfer pathway, leading to the well-characterized five-coordinate Mn(3+). We here propose and compare two hypothetical mechanisms for the mutant yeast enzyme, differing in the structure of the Mn-peroxo complex yet both involving formation of the active six-coordinate Mn(3+) and proton transfer from a second-sphere water molecule, which has substituted for the -OH of Tyr34, to the Mn-peroxo complex. Because WT and the mutant yeast MnSOD both rest in the 2+ state and become six-coordinate when oxidized up from Mn(2+), six-coordinate Mn(3+) species could also actively function in the mechanism of WT yeast MnSODs. PMID:22908245

Sheng, Yuewei; Butler Gralla, Edith; Schumacher, Mikhail; Cascio, Duilio; Cabelli, Diane E; Valentine, Joan Selverstone

2012-09-01

376

Six-coordinate manganese(3+) in catalysis by yeast manganese superoxide dismutase  

PubMed Central

Reduction of superoxide () by manganese-containing superoxide dismutase occurs through either a prompt protonation pathway, or an inner-sphere pathway, with the latter leading to formation of an observable Mn-peroxo complex. We recently reported that wild-type (WT) manganese superoxide dismutases (MnSODs) from Saccharomyces cerevisiae and Candida albicans are more gated toward the prompt protonation pathway than human and bacterial MnSODs and suggested that this could result from small structural changes in the second coordination sphere of manganese. We report here that substitution of a second-sphere residue, Tyr34, by phenylalanine (Y34F) causes the MnSOD from S. cerevisiae to react exclusively through the inner-sphere pathway. At neutral pH, we have a surprising observation that protonation of the Mn-peroxo complex in the mutant yeast enzyme occurs through a fast pathway, leading to a putative six-coordinate Mn3+ species, which actively oxidizes in the catalytic cycle. Upon increasing pH, the fast pathway is gradually replaced by a slow proton-transfer pathway, leading to the well-characterized five-coordinate Mn3+. We here propose and compare two hypothetical mechanisms for the mutant yeast enzyme, differing in the structure of the Mn-peroxo complex yet both involving formation of the active six-coordinate Mn3+ and proton transfer from a second-sphere water molecule, which has substituted for the ?OH of Tyr34, to the Mn-peroxo complex. Because WT and the mutant yeast MnSOD both rest in the 2+ state and become six-coordinate when oxidized up from Mn2+, six-coordinate Mn3+ species could also actively function in the mechanism of WT yeast MnSODs. PMID:22908245

Sheng, Yuewei; Butler Gralla, Edith; Schumacher, Mikhail; Cascio, Duilio; Cabelli, Diane E.; Selverstone Valentine, Joan

2012-01-01

377

Structural transformations in hull material clad by nitrogen stainless steel using various methods  

NASA Astrophysics Data System (ADS)

Specimens of a 10N3KhDMBF shipbuilding hull steel were clad by a 04Kh20N6G11M2AFB nitrogen austenitic steel using various treatment conditions, which included hot rolling, austenitic facing, and explosive welding followed by hot rolling and heat treatment. Between the base and cladding materials, an intermediate layer with variable concentrations of chromium, manganese, and nickel was found, in which a martensitic structure was formed. In all the cases, the strength of bonding of the cladding layer to the hull steel (determined in tests for shear to fracture) was fairly high (?sh = 437-520 MPa). The only exception was the specimen produced by unidirectional facing without subsequent hot rolling (?sh = 308 MPa), in which nonfusions between the faced beads of stainless steel were detected.

Sagaradze, V. V.; Kataeva, N. V.; Mushnikova, S. Yu.; Khar'kov, O. A.; Kalinin, G. Yu.; Yampol'skii, V. D.

2014-02-01

378

Ultrahigh carbon steels, Damascus steels, and superplasticity  

SciTech Connect

The processing properties of ultrahigh carbon steels (UHCSs) have been studied at Stanford University over the past twenty years. These studies have shown that such steels (1 to 2.1% C) can be made superplastic at elevated temperature and can have remarkable mechanical properties at room temperature. It was the investigation of these UHCSs that eventually brought us to study the myths, magic, and metallurgy of ancient Damascus steels, which in fact, were also ultrahigh carbon steels. These steels were made in India as castings, known as wootz, possibly as far back as the time of Alexander the Great. The best swords are believed to have been forged in Persia from Indian wootz. This paper centers on recent work on superplastic UHCSs and on their relation to Damascus steels. 32 refs., 6 figs.

Sherby, O.D. [Stanford Univ., CA (United States). Dept. of Materials Science and Engineering; Wadsworth, J. [Lawrence Livermore National Lab., CA (United States)

1997-04-01

379

Non-magnetic compensation in ferromagnetic Ga1-xMnxAs and Ga1-xMnxP synthesized by ion implantation and pulsed-laser melting  

SciTech Connect

The electronic and magnetic effects of intentional compensation with non-magnetic donors are investigated in the ferromagnetic semiconductors Ga1-xMnxAs and Ga1-xMnxP synthesized using ion implantation and pulsed-laser melting (II-PLM). It is demonstrated that compensation with non-magnetic donors and MnI have similarqualitative effects on materials properties. With compensation TC decreases, resistivity increases, and stronger magnetoresistance and anomalous Hall effect attributed to skew scattering are observed. Ga1-xMnxAs can be controllably compensated with Te through a metal-insulator transition through which the magnetic and electrical properties vary continuously. The resistivity of insulating Ga1-xMnxAs:Te can be described by thermal activation to the mobility edge and simply-activated hopping transport. Ga1-xMnxP doped with S is insulating at all compositions but shows decreasing TC with compensation. The existence of a ferromagnetic insulating state in Ga1-xMnxAs:Te and Ga1-xMnxP:S having TCs of the same order as the uncompensated materials demonstrates that localized holes are effective at mediating ferromagnetism in ferromagnetic semiconductors through the percolation of ferromagnetic 'puddles' which at low temperatures.

Scarpulla, M.A.; Stone, P.R.; Sharp, I.D.; Haller, E.E.; Dubon, O.D.; Beeman, J.W.; Yu, K.M.

2008-02-05

380

Effects of manganese deficiency and added cerium on nitrogen metabolism of maize.  

PubMed

Manganese is one of the essential microelements for plant growth, and cerium is a beneficial element for plant growth. However, whether manganese deficiency affects nitrogen metabolism of plants and cerium improves the nitrogen metabolism of plants by exposure to manganese-deficient media are still unclear. The main aim of the study was to determine the effects of manganese deficiency in nitrogen metabolism and the roles of cerium in the improvement of manganese-deficient effects in maize seedlings. Maize seedlings were cultivated in manganese present Meider's nutrient solution. They were subjected to manganese deficiency and to cerium chloride administered in the manganese-present and manganese-deficient media. Maize seedlings grown in the various media were measured for key enzyme activities involved in nitrogen metabolism, such as nitrate reductase, glutamate dehydrogenase, glutamine synthetase, and glutamic-oxaloace transaminase. We found that manganese deficiency restricted uptake and transport of NO(3)(-), inhibited activities of nitrogen-metabolism-related enzymes, such as nitrate reductase, glutamine synthetase, and glutamic-oxaloace transaminase, thus decreasing the synthesis of chlorophyll and soluble protein, and inhibited the growth of maize seedlings. Manganese deficiency promoted the activity of glutamate dehydrogenase and reduced the toxicity of excess ammonia to the plant, while added cerium relieved the damage to nitrogen metabolism caused by manganese deficiency in maize seedlings. However, cerium addition exerted positively to relieve the damage of nitrogen metabolism process in maize seedlings caused by exposure to manganese-deficient media. PMID:21660532

Gong, Xiaolan; Qu, Chunxiang; Liu, Chao; Hong, Mengmeng; Wang, Ling; Hong, Fashui

2011-12-01

381

Steel crisis and steel policy A comparison  

Microsoft Academic Search

The recent steel conflict between the USA and Europe has once again dramatically highlighted the close links between political\\u000a and economic strategies in this field. The world-wide steel crisis has provoked permanent state intervention in the steel\\u000a industry. The forms taken by this intervention are examined and compared here for four Western European countries: the Federal\\u000a Republic of Germany, France,

J. Esser; W. Fach; G. Gierszewski; W. Vth

1982-01-01

382

Manganese Superoxide Dismutase: Guardian of the Powerhouse  

PubMed Central

The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as ?-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component. PMID:22072939

Holley, Aaron K.; Bakthavatchalu, Vasudevan; Velez-Roman, Joyce M.; St. Clair, Daret K.

2011-01-01

383

Xenon in Mercury-Manganese Stars  

E-print Network

Previous studies of elemental abundances in Mercury-Manganese (HgMn) stars have occasionally reported the presence of lines of the ionized rare noble gas Xe II, especially in a few of the hottest stars with Teff ~ 13000--15000 K. A new study of this element has been undertaken using observations from Lick Observatory's Hamilton Echelle Spectrograph. In this work, the spectrum synthesis program UCLSYN has been used to undertake abundance analysis assuming LTE. We find that in the Smith & Dworetsky sample of HgMn stars, Xe is vastly over-abundant in 21 of 22 HgMn stars studied, by factors of 3.1--4.8 dex. There does not appear to be a significant correlation of Xe abundance with Teff. A comparison sample of normal late B stars shows no sign of Xe II lines that could be detected, consistent with the expected weakness of lines at normal abundance. The main reason for the previous lack of widespread detection in HgMn stars is probably due to the strongest lines being at longer wavelengths than the photographic blue. The lines used in this work were 4603.03A, 4844.33A and 5292.22A.

M. M. Dworetsky; J. L. Persaud; K. Patel

2008-01-16

384

Xenon in Mercury-Manganese Stars  

E-print Network

Previous studies of elemental abundances in Mercury-Manganese (HgMn) stars have occasionally reported the presence of lines of the ionized rare noble gas Xe II, especially in a few of the hottest stars with Teff ~ 13000--15000 K. A new study of this element has been undertaken using observations from Lick Observatory's Hamilton Echelle Spectrograph. In this work, the spectrum synthesis program UCLSYN has been used to undertake abundance analysis assuming LTE. We find that in the Smith & Dworetsky sample of HgMn stars, Xe is vastly over-abundant in 21 of 22 HgMn stars studied, by factors of 3.1--4.8 dex. There does not appear to be a significant correlation of Xe abundance with Teff. A comparison sample of normal late B stars shows no sign of Xe II lines that could be detected, consistent with the expected weakness of lines at normal abundance. The main reason for the previous lack of widespread detection in HgMn stars is probably due to the strongest lines being at longer wavelengths than the photographic...

Dworetsky, M M; Patel, K

2008-01-01

385

Redundancy among Manganese Peroxidases in Pleurotus ostreatus  

PubMed Central

Manganese peroxidases (MnPs) are key players in the ligninolytic system of white rot fungi. In Pleurotus ostreatus (the oyster mushroom) these enzymes are encoded by a gene family comprising nine members, mnp1 to -9 (mnp genes). Mn2+ amendment to P. ostreatus cultures results in enhanced degradation of recalcitrant compounds (such as the azo dye orange II) and lignin. In Mn2+-amended glucose-peptone medium, mnp3, mnp4, and mnp9 were the most highly expressed mnp genes. After 7 days of incubation, the time point at which the greatest capacity for orange II decolorization was observed, mnp3 expression and the presence of MnP3 in the extracellular culture fluids were predominant. To determine the significance of MnP3 for ligninolytic functionality in Mn2+-sufficient cultures, mnp3 was inactivated via the ?ku80 strain-based P. ostreatus gene-targeting system. In Mn2+-sufficient medium, inactivation of mnp3 did not significantly affect expression of nontargeted MnPs or their genes, nor did it considerably diminish the fungal Mn2+-mediated orange II decolorization capacity, despite the significant reduction in total MnP activity. Similarly, inactivation of either mnp4 or mnp9 did not affect orange II decolorization ability. These results indicate functional redundancy within the P. ostreatus MnP gene family, enabling compensation upon deficiency of one of its members. PMID:23377936

Salame, Tomer M.; Knop, Doriv; Levinson, Dana; Yarden, Oded

2013-01-01

386

Manganese Neurotoxicity: A Focus on the Neonate  

PubMed Central

Manganese (Mn) is an essential trace metal found in all tissues, and it is required for normal amino acid, lipid, protein, and carbohydrate metabolism. While Mn deficiency is extremely rare in humans, toxicity due to overexposure of Mn is more prevalent. The brain appears to be especially vulnerable. Mn neurotoxicity is most commonly associated with occupational exposure to aerosols or dusts that contain extremely high levels (> 1-5 mg Mn/m3) of Mn, consumption of contaminated well water, or parenteral nutrition therapy in patients with liver disease or immature hepatic functioning such as the neonate. This review will focus primarily on the neurotoxicity of Mn in the neonate. We will discuss putative transporters of the metal in the neonatal brain and then focus on the implications of high Mn exposure to the neonate focusing on typical exposure modes (e.g., dietary and parenteral). Although Mn exposure via parenteral nutrition is uncommon in adults, in premature infants, it is more prevalent, so this mode of exposure becomes salient in this population. We will briefly review some of the mechanisms of Mn neurotoxicity and conclude with a discussion of ripe areas for research in this underreported area of neurotoxicity. PMID:17084903

Erikson, Keith M.; Thompson, Khristy; Aschner, Judy; Aschner, Michael

2007-01-01

387

Genetic factors and manganese-induced neurotoxicity  

PubMed Central

Manganese (Mn), is a trace metal required for normal physiological processes in humans. Mn levels are tightly regulated, as high levels of Mn result in accumulation in the brain and cause a neurological disease known as manganism. Manganism shares many similarities with Parkinsons disease (PD), both at the physiological level and the cellular level. Exposure to high Mn-containing environments increases the risk of developing manganism. Mn is absorbed primarily through the intestine and then released in the blood. Excessive Mn is secreted in the bile and excreted in feces. Mn enters and exits cells through a number of non-specific importers localized on the cell membrane. Mutations in one of the Mn exporters, SLC30A10 (solute carrier family 30, member 10), result in Mn induced toxicity with liver impairments and neurological dysfunction. Four PD genes have been identified in connection to regulation of Mn toxicity, shedding new light on potential links between manganism and PD. PMID:25136353

Chen, Pan; Parmalee, Nancy; Aschner, Michael

2014-01-01

388

Heat-affected zone cracking of nitronic 60 stainless steel  

SciTech Connect

Nitronic 60 is a nitrogen-strengthened austenitic stainless steel used for applications where metal-to-metal wear and galling resistance are required. In addition, it does not transfer to martensite with strain or upon cooling to cryogenic temperatures. In comparison to type 304 stainless steel, the nickel content is similar, chromium content is slightly reduced and manganese, silicon, and nitrogen are all increased in Nitronic 60. Although studies have shown that it can be joined with arc welding, it fabrication weldability is limited by heat-affected zone (HAZ) cracking. This study examined the HAZ cracking behavior of this alloy during autogenous gas tungsten arc welding and pulsed autogenous Nd:YAG welding.

Maguire, M.C.; Robino, C.V.; Damkroger, B.K. (Sandia National Labs., Albuquerque, NM (United States)); Lienert, T.J. (Edison Welding Inst., Columbus, OH (United States))

1992-01-01

389

Heat-affected zone cracking of nitronic 60 stainless steel  

SciTech Connect

Nitronic 60 is a nitrogen-strengthened austenitic stainless steel used for applications where metal-to-metal wear and galling resistance are required. In addition, it does not transfer to martensite with strain or upon cooling to cryogenic temperatures. In comparison to type 304 stainless steel, the nickel content is similar, chromium content is slightly reduced and manganese, silicon, and nitrogen are all increased in Nitronic 60. Although studies have shown that it can be joined with arc welding, it fabrication weldability is limited by heat-affected zone (HAZ) cracking. This study examined the HAZ cracking behavior of this alloy during autogenous gas tungsten arc welding and pulsed autogenous Nd:YAG welding.

Maguire, M.C.; Robino, C.V.; Damkroger, B.K. [Sandia National Labs., Albuquerque, NM (United States); Lienert, T.J. [Edison Welding Inst., Columbus, OH (United States)

1992-09-01

390

Manganese sulfide formation via concomitant microbial manganese oxide and thiosulfate reduction.  

PubMed

The dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1 produced ?-MnS (rambergite) nanoparticles during the concurrent reduction of MnO? and thiosulfate coupled to H? oxidation. To investigate effect of direct microbial reduction of MnO? on MnS formation, two MR-1 mutants defective in outer membrane c-type cytochromes (?mtrC/?omcA and ?mtrC/?omcA/?mtrF) were also used and it was determined that direct reduction of MnO? was dominant relative to chemical reduction by biogenic sulfide generated from thiosulfate reduction. Although bicarbonate was excluded from the medium, incubations of strain MR-1 with lactate as the electron donor produced MnCO? (rhodochrosite) as well as MnS in nearly equivalent amounts as estimated by micro X-ray diffraction (micro-XRD) analysis. It was concluded that carbonate released from lactate metabolism promoted MnCO? formation and that Mn(II) mineralogy was strongly affected by carbonate ions even in the presence of abundant sulfide and weakly alkaline conditions expected to favour the precipitation of MnS. Formation of MnS, as determined by a combination of micro-XRD, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction analyses was consistent with equilibrium speciation modelling predictions. Biogenic manganese sulfide may be a manganese sink in the Mn biogeochemical cycle in select environments such as deep anoxic marine basins within the Baltic Sea. PMID:21951417

Lee, Ji-Hoon; Kennedy, David W; Dohnalkova, Alice; Moore, Dean A; Nachimuthu, Ponnusamy; Reed, Samantha B; Fredrickson, James K

2011-12-01

391

Iron and Steel Phosphate Rock  

E-print Network

Kyanite Lead Lime Lithium Magnesium Manganese Mercury Mica Molybdenum Nickel Nitrogen Peat Perlite Niobium Stone Barite Gold Nitrogen Strontium Bauxite Graphite Peat Sulfur Beryllium Gypsum Perlite Talc

Torgersen, Christian

392

Iron and Steel Phosphate Rock  

E-print Network

Kyanite Lead Lime Lithium Magnesium Manganese Mercury Mica Molybdenum Nickel Nitrogen Peat Perlite Graphite Peat Sulfur Beryllium Gypsum Perlite Talc Bismuth Hafnium Phosphate Rock Tantalum Boron Helium

Torgersen, Christian

393

OXIDATION AND SORPTION KINETICS OF ARSENIC ON A POORLY CRYSTALLINE MANGANESE OXIDE  

E-print Network

OXIDATION AND SORPTION KINETICS OF ARSENIC ON A POORLY CRYSTALLINE MANGANESE OXIDE by Brandon J. Lafferty All Rights Reserved #12;OXIDATION AND SORPTION KINETICS OF ARSENIC ON A POORLY CRYSTALLINE MANGANESE OXIDE by Brandon J. Lafferty Approved

Sparks, Donald L.

394

Parallel Polarization EPR Characterization of the Mn(III) Center of Oxidized Manganese Superoxide  

E-print Network

Parallel Polarization EPR Characterization of the Mn(III) Center of Oxidized Manganese Superoxide, Maryland 21218 ReceiVed January 22, 1999 ReVised Manuscript ReceiVed March 25, 1999 Manganese superoxide

Miller, Anne-Frances

395

Coordinate Inhibition of Cytokine-mediated Induction of Ferritin H, Manganese Superoxide Dismutase,  

E-print Network

Coordinate Inhibition of Cytokine-mediated Induction of Ferritin H, Manganese Superoxide Dismutase-inducible cytoprotective genes manganese superoxide dismutase (MnSOD), interleukin-6 (IL-6), and ferritin heavy chain (FH

Tsuji, Yoshiaki

396

The effect of paramagnetic manganese cations on 1 H MR spectroscopy of the brain  

E-print Network

The effect of paramagnetic manganese cations on 1 H MR spectroscopy of the brain K. S. Madsen1 properties of divalent manganese cations (Mn2+ ) and their in vivo resemblance to calcium cations (Ca2+ ) has

397

Kinetic and Structural Characterization of Manganese(II)-Loaded Methionyl Aminopeptidases  

E-print Network

Kinetic and Structural Characterization of Manganese(II)-Loaded Methionyl Aminopeptidases Ventris M-2556 ReceiVed May 31, 2002; ReVised Manuscript ReceiVed August 9, 2002 ABSTRACT: Manganese(II) activation

Scott, Robert A.

398

Manganese accumulation in nail clippings as a biomarker of welding fume exposure and neurotoxicity.  

PubMed

Occupational exposure to welding fumes (WF) is thought to cause Parkinson's disease (PD)-like neurological dysfunction. An apprehension that WF may accelerate the onset of PD also exists. Identifying reliable biomarkers of exposure and neurotoxicity are therefore critical for biomonitoring and neurological risk characterization of WF exposure. Manganese (Mn) in welding consumables is considered the causative factor for the neurological deficits seen in welders. Hence, we sought to determine if Mn accumulation in blood or nail clippings can be a marker for adverse exposure and neurotoxicity. To model this, rats were exposed by intratracheal instillation to dissolved or suspended fume components collected from gas metal arc-mild steel (GMA-MS) or manual metal arc-hard surfacing (MMA-HS) welding. Trace element analysis revealed selective Mn accumulation in dopaminergic brain areas, striatum (STR) and midbrain (MB), following exposure to the two fumes. This caused dopaminergic abnormality as evidenced by loss of striatal tyrosine hydroxylase (Th; 25-32% decrease) and Parkinson disease (autosomal recessive, early onset) 7 (Park7; 25-46% decrease) proteins. While blood Mn was not detectable, Mn levels in nails strongly correlated with the pattern of Mn accumulation in the striatum (R(2)=0.9386) and midbrain (R(2)=0.9332). Exposure to manganese chloride (MnCl(2)) caused similar Mn accumulation in STR, MB and nail. Our findings suggest that nail Mn has the potential to be a sensitive and reliable biomarker for long-term Mn exposure and associated neurotoxicity. The non-invasive means by which nail clippings can be collected, stored, and transported with relative ease, make it an attractive surrogate for biomonitoring WF exposures in occupational settings. PMID:22085607

Sriram, Krishnan; Lin, Gary X; Jefferson, Amy M; Roberts, Jenny R; Andrews, Ronnee N; Kashon, Michael L; Antonini, James M

2012-01-27

399

Manganese, iron, and total particulate exposures to welders.  

PubMed

Welders are exposed to a variety of metal fumes, including manganese, that may elevate the risk for neurological disease. This study examines several large data sets to characterize manganese, iron, and total particulate mass exposures resulting from welding operations. The data sets contained covariates for a variety of exposure modifiers, including the presence of ventilation, the degree of confinement, and the location of the personal sampler (i.e., behind or in front of the welding helmet). The analysis suggests that exposures to manganese are frequently at or above the current ACGIH(R) threshold limit value of 0.2 mg/m(3). In addition, there is evidence that local exhaust ventilation can control the exposures to manganese and total fume but that mechanical ventilation may not. The data suggest that higher exposures are associated with a greater degree of enclosure, particularly when local exhaust ventilation is absent. Samples taken behind the helmet were, in general, lower than those measured outside of it. There were strong correlations among manganese, iron, and total particulate mass exposures, suggesting simple equations to estimate one fume component from any of the others. PMID:20013450

Flynn, Michael R; Susi, Pam

2010-02-01

400

Manganese and iron oxidation by fungi isolated from building stone.  

PubMed

Acid and nonacid generating fungal strains isolated from weathered sandstone, limestone, and granite of Spanish cathedrals were assayed for their ability to oxidize iron and manganese. In general, the concentration of the different cations present in the mineral salt media directly affected Mn(IV) oxide formation, although in some cases, the addition of glucose and nitrate to the culture media was necessary. Mn(II) oxidation in acidogenic strains was greater in a medium containing the highest concentrations of glucose, nitrate, and manganese. High concentrations of Fe(II), glucose, and mineral salts were optimal for iron oxidation. Mn(IV) precipitated as oxides or hydroxides adhered to the mycelium. Most of the Fe(III) remained in solution by chelation with organic acids excreted by acidogenic strains. Other metabolites acted as Fe(III) chelators in nonacidogenic strains, although Fe(III) deposits around the mycelium were also detected. Both iron and manganese oxidation were shown to involve extracellular, hydrosoluble enzymes, with maximum specific activities during exponential growth. Strains able to oxidize manganese were also able to oxidize iron. It is concluded that iron and manganese oxidation reported in this work were biologically induced by filamentous fungi mainly by direct (enzymatic) mechanisms. PMID:24190274

de la Torre, M A; Gomez-Alarcon, G

1994-01-01

401

Development of a Manganese Speciation Method for Atmospheric Aerosols in Biologically and Environmentally Relevant Fluids  

Microsoft Academic Search

Because the health effects of manganese are dependent its oxidation-state, we have improved upon oxidation-state resolved methods to quantify soluble manganese in atmospheric aerosols. Two spectrophotometric methods were adapted for measurements in atmospheric aerosols in order to measure total soluble manganese (Mnsol) and soluble oxidized manganese [Mn(III) and Mn(IV), Mnox]. Using the formaldoxime method, we noted a detection limit two

Brian J. Majestic; James J. Schauer; Martin M. Shafer

2007-01-01

402

Preparation of an electrochemically-formed spinel lithium manganese oxide and its chargedischarge behaviors  

Microsoft Academic Search

Manganese hydroxides were prepared by a cathodic electrochemical precipitation from a manganese nitrate solution. The grass blade-like precipitate, which is ascribed to manganese hydroxide was 2080?m long and 15?m wide and was spread out on a Pt substrate after the electrochemical precipitation. When the electrochemically precipitated manganese hydroxides were kept in an alkali metal hydroxide aqueous solution, such as NaOH,

Katsumi Katakura; Shin-ichi Nishimura; Zempachi Ogumi

2005-01-01

403

Stress Corrosion Cracking Behavior of Cast Stainless Steels  

SciTech Connect

Casting of austenitic stainless steels offers the possibility of directly producing large and/or relatively complex structures, such as the first wall shield modules or the diverter cassette for the ITER fusion reactor. Casting offers major cost savings when compared to fabrication via welding of quarter modules machined from large forgings. However, the strength properties of such cast components are typically considered inferior to those of conventionally forged and annealed components. To improve and validate cast stainless steel as a substitute for wrought stainless steel, a development and testing program was initiated, utilizing nitrogen and manganese additions to promote improved performance. This paper focuses on the response of the first set of developmental alloys to neutron-irradiation and susceptibility to stress corrosion cracking. These cast materials may also have applications for different components in light water reactors. Results showed that all steels exhibited irradiation-induced hardening and a corresponding drop in ductility, as expected, although there is still considerable ductility in the irradiated samples. The cast steels all exhibited reduced hardening in comparison to a wrought reference steels, which may be related to a larger grain size. Higher nitrogen contents did not negatively influence irradiation performance. Regarding stress corrosion cracking susceptibility, the large difference in grain size limits the comparison between wrought and cast materials, and inclusions in a reference and archive cast alloy tests complicate analysis of these samples. Results suggest that the irradiated archive heat was more susceptible to cracking than the modified alloys, which may be related to the more complex microstructure. Further, the results suggest that the modified cast steel is at least as SCC resistant as wrought 316LN. The beneficial effect of nitrogen on the mechanical properties of the alloys remains after irradiation and is not detrimental to SCC resistance.

Teysseyre, Sebastien [University of Michigan; Busby, Jeremy T [ORNL; Was, Gary [University of Michigan

2009-01-01

404

Comminuting irradiated ferritic steel  

DOEpatents

Disclosed is a method of comminuting irradiated ferritic steel by placing the steel in a solution of a compound selected from the group consisting of sulfamic acid, bisulfate, and mixtures thereof. The ferritic steel is used as cladding on nuclear fuel rods or other irradiated components.

Bauer, Roger E. (Kennewick, WA); Straalsund, Jerry L. (Kennewick, WA); Chin, Bryan A. (Auburn, AL)

1985-01-01

405

Comminuting irradiated ferritic steel  

SciTech Connect

Disclosed is a method of comminuting irradiated ferritic steel by placing the steel in a solution of a compound selected from the group consisting of sulfamic acid, bisulfate, and mixtures thereof. The ferritic steel is used as cladding on nuclear fuel rods or other irradiated components.

Bauer, R. E.; Chin, B. A.; Straalsund, J. L.

1985-03-26

406

Welding Rustproof Steels  

NASA Technical Reports Server (NTRS)

The following experimental results will perhaps increase the knowledge of the process of welding rustproof steels. The experiments were made with two chrome-steel sheets and with two chrome-steel-nickel sheets having the composition shown in Table I.

Hoffmann, W

1929-01-01

407

Exposure to Manganese: Health Effects on the General Population, a Pilot Study in Central Mexico  

Microsoft Academic Search

To support a risk assessment of manganese exposure in two communities living within a manganese mining district a cross-sectional study was performed on a sample of the adult population of long-term residents. One community was exposed to a point source from an ore primary refining plant. Manganese is an essential mineral for human life. It is also the fourth in

Carlos Santos-Burgoa; Camilo Rios; Luis Alberto Mercado; Rodolfo Arechiga-Serrano; Fernando Cano-Valle; Rocio Alatorre Eden-Wynter; Jose Luis Texcalac-Sangrador; Juan Pablo Villa-Barragan; Yanneth Rodriguez-Agudelo; Sergio Montes

2001-01-01

408

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Lithium manganese oxide (LiMn204) (generic...Specific Chemical Substances 721.4587 Lithium manganese oxide (LiMn204) (generic...chemical substance identified generically as lithium manganese oxide (LiMn204)...

2011-07-01

409

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Lithium manganese oxide (LiMn204) (generic...Specific Chemical Substances 721.4587 Lithium manganese oxide (LiMn204) (generic...chemical substance identified generically as lithium manganese oxide (LiMn204)...

2010-07-01

410

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Lithium manganese oxide (LiMn204) (generic...Specific Chemical Substances 721.4587 Lithium manganese oxide (LiMn204) (generic...chemical substance identified generically as lithium manganese oxide (LiMn204)...

2013-07-01

411

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Lithium manganese oxide (LiMn204) (generic...Specific Chemical Substances 721.4587 Lithium manganese oxide (LiMn204) (generic...chemical substance identified generically as lithium manganese oxide (LiMn204)...

2012-07-01

412

75 FR 70583 - Cobalt Lithium Manganese Nickel Oxide; Withdrawal of Significant New Use Rule  

Federal Register 2010, 2011, 2012, 2013

...FRL-8853-2] RIN 2070-AB27 Cobalt Lithium Manganese Nickel Oxide; Withdrawal of...chemical substance identified as cobalt lithium manganese nickel oxide (CAS No. 182442-95-1...withdrawing the rule issued for cobalt lithium manganese nickel oxide (PMN...

2010-11-18

413

The pigeon ( Columbia livia ) as a monitor for manganese contamination from motor vehicles  

Microsoft Academic Search

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn) used in unleaded gasoline in Canada since 1977. It has been suggested that the production of Mn3O4 resulting from the combustion of MMT may become one of the principal sources of manganese contamination in the urban environment. This research evaluates the feral pigeon (Columba livia) as a monitor of

S. Loranger; G. Demers; G. Kennedy; E. Forget; J. Zayed

1994-01-01

414

Response of blue spruce ( Picea pungens ) to manganese pollution from MMT  

Microsoft Academic Search

The use of methylcyclopentadienyl manganese tricarbonyl (MMT) in unleaded gasoline has become a source of manganese (Mn) contamination to which urban ecosystems are exposed. The potential of coniferous trees as spatial and chronological indicators of Mn pollutation was investigated. Manganese concentrations in xylem from blue spruce (Picea pungens) growing near (high-exposure site) and far (low-exposure site) from a road were

E. Forget; F. Courchesne; G. Kennedy; J. Zayed

1994-01-01

415

Effect of manganese additives on NO-emissions from a small laboratory oil burner  

Microsoft Academic Search

Manganese compounds, particularly manganese naphthenate (MnN) and methylcyclopentadienyl manganese tricarbonyl (MMT), have been used as additives in No. 2 distillate fuel oil and their effect on NO levels in both oil diffusion flame and the exhaust gases has been determined. NO concentrations in the exhaust gas were lowered 15 to 35% over baseline concentrations at equivalence ratios slightly less than

E. R. Altwicker; I. S. Brodsky; T. T. Shen

1974-01-01

416

Selenium Induces Manganese-dependent Peroxidase Production by the White-Rot Fungus Bjerkandera adusta  

E-print Network

Selenium Induces Manganese-dependent Peroxidase Production by the White-Rot Fungus Bjerkandera, selenium (Se) induction of the ligninolytic enzyme manganese- dependent peroxidase (MnP) production-rot fungi. Keywords Lipid peroxidation . Manganese peroxidase . Selenium . White-rot fungi Abbreviations Ag

Tullos, Desiree

417

Transformation from layered to tunnel structures: Synthesis, characterization, and applications of manganese oxide octahedral molecular sieves  

Microsoft Academic Search

Manganese oxide based octahedral molecular sieves (OMS) have been found to have a wide variety of applications as catalysts, absorbents, and battery materials due to their unique structures and physical and chemical properties. OMS materials are made up of manganese oxide octahedral building blocks sharing comers and edges to form tunnel structures. Manganese species in the framework of OMS materials

Guan-Guang Xia

2001-01-01

418

Modeling manganese removal in chelating polymer-assisted membrane separation systems for water treatment  

Microsoft Academic Search

The removal of manganese from groundwater, using water-soluble chelating polymers such as polyacrylic acid (PAA) in combination with ultrafiltration (UF), was investigated. The effects of the solution pH and polymer dosages on the manganese removal were evaluated, and the removal efficiency was modeled considering the relevant chemical equilibria. In the absence of polymer, manganese removal with UF membranes alone was

Sang-Chul Han; Kwang-Ho Choo; Sang-June Choi; Mark M. Benjamin

2007-01-01

419

Development of Integrated In Situ Analyzer for Manganese (IISA-Mn) in Deep Sea Environment  

Microsoft Academic Search

Manganese is a metal ion that can be found at ultra trace level in the ocean. Mainly, manganese comes into the ocean through hydrothermal vents. Usually, determination of manganese concentration is done by sampling seawater in bottles and measuring afterward onboard a ship or in a lab on the ground. Major drawbacks of that method are that only a few

Christophe Provin; Tatsuhiro Fukuba; T. Fujii

2007-01-01

420

40 CFR 721.10008 - Manganese strontium oxide (MnSrO3).  

...2014-07-01 2014-07-01 false Manganese strontium oxide (MnSrO3). 721...Chemical Substances 721.10008 Manganese strontium oxide (MnSrO3 ). ...The chemical substance identified as manganese strontium oxide (MnSrO3 )...

2014-07-01

421

Manganese exposure from drinking water and children's academic achievement Khalid Khan a  

E-print Network

Manganese exposure from drinking water and children's academic achievement Khalid Khan a , Gail A Health, Department of Epidemiology, United States 1. Introduction Health effects of chronic manganese (Mn: Received 28 September 2011 Accepted 2 December 2011 Available online 13 December 2011 Keywords: Manganese

van Geen, Alexander

422

40 CFR 721.10013 - Manganese yttrium oxide (Mn2YO5).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Manganese yttrium oxide (Mn2YO5). 721.10013...Chemical Substances 721.10013 Manganese yttrium oxide (Mn2 YO5 ). ...The chemical substance identified as manganese yttrium oxide (Mn2 YO5 )...

2013-07-01

423

Disruption of Astrocytic Glutamine Turnover by Manganese Is Mediated by the Protein Kinase C Pathway  

E-print Network

Disruption of Astrocytic Glutamine Turnover by Manganese Is Mediated by the Protein Kinase C, Nashville, Tennessee KEY WORDS glutamine transporter; manganese; protein kinase C; ubiq- uitination ABSTRACT Manganese (Mn) is a trace element essential for normal human development and is required for the proper func

Palmeri, Thomas

424

Vesicular distribution of Secretory Pathway Ca2+ isoform 1 and a role in manganese detoxification  

E-print Network

Vesicular distribution of Secretory Pathway Ca2+ -ATPase isoform 1 and a role in manganese+Business Media, LLC. 2010 Abstract Manganese is a trace element that is an essential co-factor in many enzymes suggest a role for SPCA1 in Mn2? detoxification in liver. Keywords Manganese Á Ca2? -ATPase Á Liver Á

Rao, Rajini

425

40 CFR 721.4587 - Lithium manganese oxide (LiMn204) (generic name).  

...2014-07-01 2014-07-01 false Lithium manganese oxide (LiMn204) (generic name...Chemical Substances 721.4587 Lithium manganese oxide (LiMn204) (generic name...substance identified generically as lithium manganese oxide (LiMn204)...

2014-07-01

426

40 CFR 721.10008 - Manganese strontium oxide (MnSrO3).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Manganese strontium oxide (MnSrO3). 721...Chemical Substances 721.10008 Manganese strontium oxide (MnSrO3 ). ...The chemical substance identified as manganese strontium oxide (MnSrO3 )...

2012-07-01

427

Kinetics of manganese adsorption, desorption, and oxidation in coastal marine sediments  

E-print Network

Kinetics of manganese adsorption, desorption, and oxidation in coastal marine sediments Dominique´bec a` Rimouski, Que´bec, Canada Abstract Ejection of excavated manganese (Mn)-laden particles from disturbances triggers desorption and oxidation of reduced manganese species. These competing reactions

Beaudoin, Georges

428

40 CFR 721.10009 - Manganese yttrium oxide (MnYO3).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Manganese yttrium oxide (MnYO3). 721.10009...Chemical Substances 721.10009 Manganese yttrium oxide (MnYO3). (a) Chemical...The chemical substance identified as manganese yttrium oxide (MnYO3 ) (PMN...

2010-07-01

429

Localization and Role of Manganese Superoxide Dismutase in a Marine Diatom1[OA  

E-print Network

Localization and Role of Manganese Superoxide Dismutase in a Marine Diatom1[OA] Felisa Wolfe-Simon2 by their metal cofactor (iron, manganese [Mn], copper/zinc, nickel), MnSOD is the dominant form in the diatom in four isoforms, recognized by their metal center cofactors (iron [Fe], manganese [Mn], copper [Cu

430

Layer-Specific Manganese-Enhanced MRI of the Retina in Light and Dark Adaptation  

E-print Network

Retina Layer-Specific Manganese-Enhanced MRI of the Retina in Light and Dark Adaptation Bryan H. De manganese-enhanced MRI (MEMRI) to image layer-specific changes in calcium-dependent activities in the rat retina have also been demonstrated. Functional manganese-enhanced MRI (MEMRI)20,21 has also been used

Duong, Timothy Q.

431

Manganese porphyrin multilayer films assembled on ITO electrodes via zirconium phosphonate chemistry: chemical and electrochemical  

E-print Network

Manganese porphyrin multilayer films assembled on ITO electrodes via zirconium phosphonate University, 2145 Sheridan Road, Evanston, IL 60208-3113 A supported manganese porphyrin-based oxidation)porphyrinato] manganese(III) chloride (2) and zirconium(IV) ions on indium�tin oxide electrodes. This assembly technique

432

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

...2014-07-01 2014-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances 721.10010 Barium manganese oxide (BaMnO3 ). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2014-07-01

433

40 CFR 721.10009 - Manganese yttrium oxide (MnYO3).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Manganese yttrium oxide (MnYO3). 721.10009...Chemical Substances 721.10009 Manganese yttrium oxide (MnYO3 ). (a...The chemical substance identified as manganese yttrium oxide (MnYO3 ) (PMN...

2013-07-01

434

40 CFR 721.10013 - Manganese yttrium oxide (Mn2YO5).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Manganese yttrium oxide (Mn2YO5). 721.10013...Chemical Substances 721.10013 Manganese yttrium oxide (Mn2 YO5 ). ...The chemical substance identified as manganese yttrium oxide (Mn2 YO5 )...

2012-07-01

435

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances 721.10010 Barium manganese oxide (BaMnO3 ). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2013-07-01

436

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2010-07-01

437

40 CFR 721.10008 - Manganese strontium oxide (MnSrO3).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Manganese strontium oxide (MnSrO3). 721...Chemical Substances 721.10008 Manganese strontium oxide (MnSrO3 ). ...The chemical substance identified as manganese strontium oxide (MnSrO3 )...

2013-07-01

438

STRUCTURE AND REACTIVITY STUDY OF BIOTIC AND ABIOTIC POORLY CRYSTALLINE MANGANESE OXIDES  

E-print Network

STRUCTURE AND REACTIVITY STUDY OF BIOTIC AND ABIOTIC POORLY CRYSTALLINE MANGANESE OXIDES Rights Reserved #12;STRUCTURE AND REACTIVITY STUDY OF BIOTIC AND ABIOTIC POORLY CRYSTALLINE MANGANESE. Luther, III who inspired me on manganese reaction mechanisms in many helpful discussions, and Dr. Thomas

Sparks, Donald L.

439

Western Pacific coastal sources of iron, manganese, and aluminum to the Equatorial Undercurrent  

E-print Network

Western Pacific coastal sources of iron, manganese, and aluminum to the Equatorial Undercurrent Lia results from the first zonal transect of iron, aluminum, and manganese conducted from the western source, aluminum, and manganese were evident in the EUC. These maxima were generally greatest in the western

Murray, James W.

440

40 CFR 721.10009 - Manganese yttrium oxide (MnYO3).  

...2014-07-01 2014-07-01 false Manganese yttrium oxide (MnYO3). 721.10009...Chemical Substances 721.10009 Manganese yttrium oxide (MnYO3 ). (a...The chemical substance identified as manganese yttrium oxide (MnYO3 ) (PMN...

2014-07-01

441

40 CFR 721.10009 - Manganese yttrium oxide (MnYO3).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Manganese yttrium oxide (MnYO3). 721.10009...Chemical Substances 721.10009 Manganese yttrium oxide (MnYO3). (a) Chemical...The chemical substance identified as manganese yttrium oxide (MnYO3 ) (PMN...

2011-07-01

442

40 CFR 721.10008 - Manganese strontium oxide (MnSrO3).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Manganese strontium oxide (MnSrO3). 721...Chemical Substances 721.10008 Manganese strontium oxide (MnSrO3). (a...The chemical substance identified as manganese strontium oxide (MnSrO3 )...

2010-07-01

443

40 CFR 721.10013 - Manganese yttrium oxide (Mn2YO5).  

...2014-07-01 2014-07-01 false Manganese yttrium oxide (Mn2YO5). 721.10013...Chemical Substances 721.10013 Manganese yttrium oxide (Mn2 YO5 ). ...The chemical substance identified as manganese yttrium oxide (Mn2 YO5 )...

2014-07-01

444

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2011-07-01

445

40 CFR 721.10008 - Manganese strontium oxide (MnSrO3).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Manganese strontium oxide (MnSrO3). 721...Chemical Substances 721.10008 Manganese strontium oxide (MnSrO3). (a...The chemical substance identified as manganese strontium oxide (MnSrO3 )...

2011-07-01

446

40 CFR 721.10009 - Manganese yttrium oxide (MnYO3).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Manganese yttrium oxide (MnYO3). 721.10009...Chemical Substances 721.10009 Manganese yttrium oxide (MnYO3 ). (a...The chemical substance identified as manganese yttrium oxide (MnYO3 ) (PMN...

2012-07-01

447

Kinetics of Ion Removal from an Iron-Rich Industrial Coproduct: III. Manganese and Chromium  

E-print Network

Kinetics of Ion Removal from an Iron-Rich Industrial Coproduct: III. Manganese and Chromium Yigal by employing adsorption isotherms, column studies, and the stirred-flow (SF) kinetic technique. Manganese characteristics from the IRM, and (ii) to ascertain the kinetics of Mn and Cr removal from the IRM. Manganese

Sparks, Donald L.

448

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances 721.10010 Barium manganese oxide (BaMnO3 ). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2012-07-01

449

40 CFR 721.10013 - Manganese yttrium oxide (Mn2YO5).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Manganese yttrium oxide (Mn2YO5). 721.10013...Chemical Substances 721.10013 Manganese yttrium oxide (Mn2YO5). (a...The chemical substance identified as manganese yttrium oxide (Mn2 YO5 )...

2010-07-01

450

40 CFR 721.10013 - Manganese yttrium oxide (Mn2YO5).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Manganese yttrium oxide (Mn2YO5). 721.10013...Chemical Substances 721.10013 Manganese yttrium oxide (Mn2YO5). (a...The chemical substance identified as manganese yttrium oxide (Mn2 YO5 )...

2011-07-01

451

New insights into manganese toxicity and speciation.  

PubMed

Manganese (Mn) is known to be a neurotoxic agent for nearly 175 years now. A lot of research has therefore been carried out over the last century. From preliminary describing only symptoms of Mn-(over)exposed workers, research was preceded to more detail on toxic mechanisms of Mn. Unraveling those neurotoxic mechanisms implicated a number of studies, which were summarized partly in several reviews (e.g. Yokel RA. Neuromol Med 2009;11(4):297-310; Aschner M, et al. Toxicology Appl Pharmacol 2007;221(2):131-47; Michalke B, et al. J Environ Monit 2007;9(7):650). Since our recent review on Mn-speciation in 2007 (Michalke B, et al. J Environ Monit 2007;9(7):650), Mn-research was considerably pushed forward and several new research articles were published. The very recent years though, Mn toxicity investigating science is spreading into different fields with very detailed and complex study designs. Especially the mechanisms of Mn-induced neuronal injury on cellular and molecular level was investigated in more detail, discussing neurotransmitter and enzyme interactions, mechanisms of action on DNA level and even inclusion of genetic influences. Depicting the particular Mn-species was also a big issue to determine which molecule is transporting Mn at the cell membranes and which one is responsible for the injury of neuronal tissue. Other special foci on epidemiologic studies were becoming more and more important: These foci were directed toward environmental influences of Mn on especially Parkinson disease prevalence and the ability to carry out follow-up studies about Mn-life-span exposure. All these very far-reaching research applications may finally lead to a suitable future human Mn-biomonitoring for being able to prevent or at least detect the early onset of manganism at the right time. PMID:24200516

Michalke, Bernhard; Fernsebner, Katharina

2014-04-01

452

Manganese superoxide dismutase: beyond life and death  

PubMed Central

Manganese superoxide dismutase (MnSOD) is a nuclear-encoded antioxidant enzyme that localizes to the mitochondria. Expression of MnSOD is essential for the survival of aerobic life. Transgenic mice expressing a luciferase reporter gene under the control of the human MnSOD promoter demonstrate that the level of MnSOD is reduced prior to the formation of cancer. Overexpression of MnSOD in transgenic mice reduces the incidences and multiplicity of papillomas in a DMBA/TPA skin carcinogenesis model. However, MnSOD deficiency does not lead to enhanced tumorigenicity of skin tissue similarly treated because MnSOD can modulate both the p53-mediated apoptosis and AP-1-mediated cell proliferation pathways. Apoptosis is associated with an increase in mitochondrial levels of p53 suggesting a link between MnSOD deficiency and mitochondrial-mediated apoptosis. Activation of p53 is preventable by application of a SOD mimetic (MnTE-2-PyP5+). Thus, p53 translocation to mitochondria and subsequent inactivation of MnSOD explain the observed mitochondrial dysfunction that leads to transcription-dependent mechanisms of p53-induced apoptosis. Administration of MnTE-2-PyP5+ following apoptosis but prior to proliferation leads to suppression of protein carbonyls and reduces the activity of AP-1 and the level of the proliferating cellular nuclear antigen, without reducing the activity of p53 or DNA fragmentation following TPA treatment. Remarkably, the incidence and multiplicity of skin tumors are drastically reduced in mice that receive MnTE-2-PyP5+ prior to cell proliferation. The results demonstrate the role of MnSOD beyond its essential role for survival and suggest a novel strategy for an antioxidant approach to cancer intervention. PMID:20454814

Holley, Aaron K.; Dhar, Sanjit Kumar; Xu, Yong

2010-01-01

453

Biological Superoxide In Manganese Oxide Formation  

NASA Astrophysics Data System (ADS)

Manganese (Mn) oxides are among the strongest sorbents and oxidants within the environment, controlling the fate and transport of numerous elements and the degradation of recalcitrant carbon. Both bacteria and fungi mediate the oxidation of Mn(II) to Mn(III/IV) oxides but the genetic and biochemical mechanisms responsible remain poorly understood. Furthermore, the physiological basis for microbial Mn(II) oxidation remains an enigma. We have recently reported that a common marine bacterium (Roseobacter sp. AzwK-3b) oxidizes Mn(II) via reaction with extracellular superoxide (O2-) produced during exponential growth. Here we expand this superoxide-mediated Mn(II) oxidation pathway to fungi, introducing a surprising homology between prokaryotic and eukaryotic metal redox processes. For instance, Stibella aciculosa, a common soil Ascomycete filamentous fungus, precipitates Mn oxides at the base of asexual reproductive structures (synnemata) used to support conidia (Figure 1). This distribution is a consequence of localized production of superoxide (and it's dismutation product hydrogen peroxide, H2O2), leading to abiotic oxidation of Mn(II) by superoxide. Disruption of NADPH oxidase activity using the oxidoreductase inhibitor DPI leads to diminished cell differentiation and subsequent Mn(II) oxidation inhibition. Addition of Cu(II) (an effective superoxide scavenger) leads to a concentration dependent decrease in Mn oxide formation. We predict that due to the widespread production of extracellular superoxide within the fungal and likely bacterial kingdoms, biological superoxide may be an important contributor to the cycling of Mn, as well as other metals (e.g., Hg, Fe). Current and future explorations of the genes and proteins involved in superoxide production and Mn(II) oxidation will ideally lend insight into the physiological and biochemical basis for these processes.

Hansel, C.; Learman, D.; Zeiner, C.; Santelli, C. M.

2011-12-01

454

Structural state and magnetic properties of cementite alloyed with manganese  

NASA Astrophysics Data System (ADS)

Using X-ray diffraction analysis, Mssbauer spectroscopy, and magnetic measurements, the structure, parameters of hyperfine interactions, localization of Mn atoms in the lattice, coercive force, and specific saturation magnetization have been investigated in the mechanically alloyed and annealed cementite (alloyed with manganese) of compositions (Fe1 - x Mn x )3C ( x = 0-0.12). It has been shown that strongly deformed cementite resides in the low-coercivity state and, after annealing in the vicinity of 500C, in the high-coercivity state. Alloying with manganese reduces the coercive force, the specific saturation magnetization, and the Curie temperature of cementite. Inhomogeneities of the distribution of manganese atoms indicate the temperature dependence of the coercive force of mechanically alloyed and annealed cementite samples.

Ul'yanov, A. I.; Chulkina, A. A.; Volkov, V. A.; Elsukov, E. P.; Zagainov, A. V.; Protasov, A. V.; Zykina, I. A.

2012-12-01

455

High manganese concentrations in rocks at Gale crater, Mars  

NASA Astrophysics Data System (ADS)

surface of Mars has long been considered a relatively oxidizing environment, an idea supported by the abundance of ferric iron phases observed there. However, compared to iron, manganese is sensitive only to high redox potential oxidants, and when concentrated in rocks, it provides a more specific redox indicator of aqueous environments. Observations from the ChemCam instrument on the Curiosity rover indicate abundances of manganese in and on some rock targets that are 1-2 orders of magnitude higher than previously observed on Mars, suggesting the presence of an as-yet unidentified manganese-rich phase. These results show that the Martian surface has at some point in time hosted much more highly oxidizing conditions than has previously been recognized.

Lanza, Nina L.; Fischer, Woodward W.; Wiens, Roger C.; Grotzinger, John; Ollila, Ann M.; Cousin, Agnes; Anderson, Ryan B.; Clark, Benton C.; Gellert, Ralf; Mangold, Nicolas; Maurice, Sylvestre; Le Moulic, Stphane; Nachon, Marion; Schmidt, Mariek; Berger, Jeffrey; Clegg, Samuel M.; Forni, Olivier; Hardgrove, Craig; Melikechi, Noureddine; Newsom, Horton E.; Sautter, Violaine

2014-08-01

456

Metallic solvent extraction of manganese and titanium from ferroalloys  

NASA Astrophysics Data System (ADS)

The selective removal of valuable elements from ferroalloys has been investigated. It has been found that liquid bismuth is a suitable solvent for leaching manganese from its ferroalloy. High recoveries and rapid reaction rates were obtained for low-carbon ferromanganese, but results for the high-carbon ferromanganese and silicomanganese were less favorable due to the lower activity of manganese in these alloys and the lack of wetting by liquid bismuth. Antimony was found to be a suitable solvent for titanium from ferrotitanium but iron was also taken into solution. Manganese was successfully transferred from solution in liquid bismuth to liquid aluminum by fused salt electrorefining, using a NaCl-KCl-MnCl electrolyte, at high current efficiencies with negligible carryover of bismuth.

Godsell, A. J.; Fray, D. J.

1990-04-01

457

Steel slag in acid mine drainage treatment and control  

SciTech Connect

Steel slags are composed of calcium alumino-silicate oxides. Most slags have a sandy texture, but others have a silty texture and give a fine, powdery feel. Neutralization potentials of steel slags range from 45 to 78%, which make them candidates for neutralizing the acidity in acid mine drainage. Analysis of total metal content in Mingo Junction steel slab shows high concentrations of aluminum, chromium, iron, manganese, and titanium. Upon leaching this slag with water, the leachate had a pH of 11.7 and n alkalinity of 1,450 mg/L as CaCO{sub 3} equivalent. In general, steel slag yielded more alkalinity than equal weights of limestone (500 to 1,500 mg/L compared to 60 to 80 mg/L) during leaching studies. Leaching the slag with water and a weak sulfuric acid solution showed that the metals contained in the slag were not readily leachable since these metals were found at low concentrations in the leachate. When different amounts of slag were mixed with an acid-producing coal refuse and then leached with water, pH values of the leachate varied between 3.5 and 7.3. Slightly elevated levels of selenium, nickel, manganese, and possibly iron were found in leachates of refuse/slag mixtures compared to refuse alone. Due to slag's high availability in some areas and low cost, steel slags show potential as an acid-neutralizing material for coal refuse and acid-producing spoils, and for treating acid mine drainage directly. If slag is to be used as an alkaline amendment, it must be added in sufficient quantities to ensure nonacid conditions now and in the future, since under acid conditions some metals may become available. Steel slag can also be used as a liming material for soils. The most promising use for steel slag is as a source of alkalinity to fresh waters that may subsequently encounter acid mine drainage, such as alkaline leach beds or limestone sand applications to headwater streams.

Ziemkiewicz, P.; Skousen, J.

1999-07-01

458

The sensitized luminescence of manganese-activated calcite  

USGS Publications Warehouse

Synthetic manganese-activated calcites are shown to be practically inert to ultraviolet excitation in the range 2000-3500A, while they are luminescent under cathode-ray excitation. The incorporation of small amounts of an auxiliary impurity along with the manganese produces the strong response to ultraviolet radiation hitherto ascribed to CaCO3:Mn itself. Three such impurities have been studied: lead, thallium, and cerium. The first two induce excitation in the neighborhood of the mercury resonance line, while the cerium introduces a response principally to longer wave ultraviolet. The strong response to 2537A excitation shown by some natural calcites is likewise found to be due to the presence of lead along with the manganese, rather than to the manganese alone. The data do not warrant ascribing the longer wave-length ultraviolet-excited luminescence of all natural calcites to the action of an auxiliary impurity. The essential identity of the cathode-ray excited luminescence spectra of CaCO 3:Mn, CaCO3: (Pb+Mn), CaCO3:(Tl+Mn), and CaCO3:(Ce+Mn) with the 2537A-excited spectra of the latter three is evidence that the luminescent center in all cases is the manganese ion or the MnO6 group. It is shown that a "cascade" mechanism for the action of the auxiliary impurities, lead, thallium, and cerium, is incorrect; and that the phenomenon must be considered as a case of sensitized luminescence. Owing to the nature of cathode-ray excitation, the manganese activator can be excited by this agent even in the absence of a second impurity. For optical excitation, however, an absorption band for the ultraviolet must be established by building into the CaCO3:Mn a second impurity or "sensitizer.".

Schulman, J.H.; Evans, L.W.; Ginther, R.J.; Murata, K.J.

1947-01-01

459

Manganese oxidation state mediates toxicity in PC12 cells  

SciTech Connect

The role of the manganese (Mn) oxidation state on cellular Mn uptake and toxicity is not well understood. Therefore, undifferentiated PC12 cells were exposed to 0-200 {mu}M Mn(II)-chloride or Mn(III)-pyrophosphate for 24 h, after which cellular manganese levels were measured along with measures of cell viability, function, and cytotoxicity (trypan blue exclusion, medium lactate dehydrogenase (LDH), 8-isoprostanes, cellular ATP, dopamine, serotonin, H-ferritin, transferrin receptor (TfR), Mn-superoxide dismutase (MnSOD), and copper-zinc superoxide dismutase (CuZnSOD) protein levels). Exposures to Mn(III) >10 {mu}M produced 2- to 5-fold higher cellular manganese levels than equimolar exposures to Mn(II). Cell viability and ATP levels both decreased at the highest Mn(II) and Mn(III) exposures (150-200 {mu}M), while Mn(III) exposures produced increases in LDH activity at lower exposures ({>=}50 {mu}M) than did Mn(II) (200 {mu}M only). Mn(II) reduced cellular dopamine levels more than Mn(III), especially at the highest exposures (50% reduced at 200 {mu}M Mn(II)). In contrast, Mn(III) produced a >70% reduction in cellular serotonin at all exposures compared to Mn(II). Different cellular responses to Mn(II) exposures compared to Mn(III) were also observed for H-ferritin, TfR, and MnSOD protein levels. Notably, these differential effects of Mn(II) versus Mn(III) exposures on cellular toxicity could not simply be accounted for by the different cellular levels of manganese. These results suggest that the oxidation state of manganese exposures plays an important role in mediating manganese cytotoxicity.

Reaney, S.H. [Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064 (United States) and Department of Environmental Toxicology, University of California, 1156 High St., Santa Cruz, CA 95064 (United States)]. E-mail: stevereaney@hotmail.com; Smith, D.R. [Department of Environmental Toxicology, University of California, 1156 High St., Santa Cruz, CA 95064 (United States)

2005-06-15

460

Manganese-Induced Parkinsonism due to Ephedrone Abuse  

PubMed Central

During recent years, a syndrome of hypokinesia, dysarthria, dystonia, and postural impairment, related to intravenous use of a designer psychostimulant derived from pseudoephedrine using potassium permanganate as the oxidant, has been observed in drug addicts in several countries in Eastern Europe with some cases also in Western countries. A levodopa unresponsive Parkinsonian syndrome occurs within a few months of abusing the homemade drug mixture containing ephedrone (methcathinone) and manganese. The development of this neurological syndrome has been attributed to toxic effects of manganese, but the role of the psychostimulant ephedrone is unclear. This paper describes the clinical syndrome, results of neuroimaging, and therapeutic attempts. PMID:21403909

Sikk, Katrin; Haldre, Sulev; Aquilonius, Sten-Magnus; Taba, Pille

2011-01-01

461

The thermal stability of lithium-manganese-oxide spinel phases  

SciTech Connect

The thermal stability of stoichiometric spinel phases in the system Li{sub 1+{delta}}Mn{sub 2{minus}{delta}}O{sub 4} (0 {le} {delta} {le} 0.33) has been investigated by high-temperature powder X-ray diffraction, differential thermal analysis, and thermogravimetric analysis. At elevated temperatures, the lithium-manganese-oxide spinels undergo phase changes by loss of oxygen and lithia (Li{sub 2}O). The data highlight the importance of temperature control when synthesizing lithium-manganese-oxide spinel compounds.

Thackeray, M.M.; Mansuetto, M.F.; Dees, D.W.; Vissers, D.R. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States)

1996-02-01

462

Electrochemical properties of iodine-containing lithium manganese oxide spinel  

Microsoft Academic Search

Iodine-containing, cation-deficient, lithium manganese oxides (ICCD-LMO) are prepared by reaction of MnO2 with LiI. The MnO2 is completely transformed into spinel-structured compounds with a nominal composition of Li1??Mn2?2?O4Ix. A sample prepared at 800C, viz. Li0.99Mn1.98O4I0.02, exhibits an initial discharge capacity of 113mAhg?1 with good cycleability and rate capability in the 4-V region. Iodine-containing, lithium-rich lithium manganese oxides (ICLR-LMO) are also

Chi-Hwan Han; Young-Sik Hong; Hyun-Sil Hong; Keon Kim

2002-01-01

463

Study on spin polarization of non-magnetic atom in diluted magnetic semiconductor: The case of Al-doped 4H-SiC  

NASA Astrophysics Data System (ADS)

Determining the atomic origin of magnetism in non-magnetic elements doped dilute magnetic semiconductors (DMS) is a key issue to understand the room temperature ferromagnetism. Here, using electron magnetic circular dichroism (EMCD), an element-selectivity and high spatial resolution technique, we provide unambiguous experimental evidence: spin polarization of carbon atoms contributes to the local magnetic moments of Al-doped 4H-SiC DMS. The result is further confirmed by first-principle calculations. The atomic origin of the magnetism in Al-doped 4H-SiC was pinpointed. Electron magnetic circular dichroism signals were observed in nonmagnetic C atoms. No electron magnetic circular dichroism signals were observed in Si and Al atoms. The spin polarization of C atoms was confirmed by first principles calculations.

He, Ming; He, X.; Lin, L.; Song, B.; Zhang, Z. H.

2014-11-01

464

Steel penetration in sand molds. Final technical report, September 1994--September 1997  

SciTech Connect

The research program was successful in identifying the major factoirs that influence penetration. This was done first through a case study of penetration samples. The study revealed that both chemical and mechanical penetration were present in carbon and high manganese steels. It also found that only mechanical penetration is found in stainless steel samples. It should be noted that when mechanical penetration does occur, there is a greater risk of chemical reactions with the mold. Therefore, it is common to confuse mechanical penetration with chemical. Sessile drop experiments were run to discover the effect of steel chemistry on the contact angle for different substrates. These experiments revealed the best substrates for each type of metal. Bauxite, magnesite, and mullite were discovered to be the best materials for resisting mechanical penetration. It was also shown that high manganese steels cannot be poured into silica molds and that stainless steel should not be poured in chromite molds. The sessile drop data was used to develop a mechanical penetration model which correctly predicted penetration in sixteen of twenty castings poured at the University of Alabama. Mold/metal atmosphere tests were run to understand the effects of the atmosphere on chemical penetration. It was found that the chemistry affecting penetration has its greatest effect as the casting is just poured. Chemical penetration for low carbon steels cannot be completely eliminated by adding carbon (seacoal) to green sand molds although a marked decrease is obtained in its severity. Extremely high carbon concentrations might be able to totally eliminate the penetration but are not used because of their possible diffusion into the steel causing carburization. A chemical penetration model was produced and its results agree well with the experimental results.

Hayes, K.D.; Owens, M.; Barlow, J.; Stefanescu, D.M.; Lane, A.M.; Piwonka, T.S.

1997-12-01

465

Manganese sulfide formation via concomitant microbial manganese oxide and thiosulfate reduction  

SciTech Connect

The dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1 produced {gamma}-MnS (rambergite) nanoparticles during the concurrent reduction of MnO{sub 2} and thiosulfate coupled to H{sub 2} oxidation. To investigate effect of direct microbial reduction of MnO{sub 2} on MnS formation, two MR-1 mutants defective in outer membrane c-type cytochromes ({Delta}mtrC/{Delta}omcA and {Delta}mtrC/{Delta}omcA/{Delta}mtrF) were also used and it was determined that direct reduction of MnO{sub 2} was dominant relative to chemical reduction by biogenic sulfide generated from thiosulfate reduction. Although bicarbonate was excluded from the medium, incubations of strain MR-1 with lactate as the electron donor produced MnCO{sub 3} (rhodochrosite) as well as MnS in nearly equivalent amounts as estimated by micro X-ray diffraction (micro-XRD) analysis. It was concluded that carbonate released from lactate metabolism promoted MnCO{sub 3} formation and that Mn(II) mineralogy was strongly affected by carbonate ions even in the presence of abundant sulfide and weakly alkaline conditions expected to favor the precipitation of MnS. Formation of MnS, as determined by a combination of micro-XRD, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction analyses was consistent with equilibrium speciation modeling predictions. Biogenic manganese sulfide may be a manganese sink in the Mn biogeochemical cycle in select environments such as deep anoxic marine basins within the Baltic Sea.

Lee, Ji-Hoon; Kennedy, David W.; Dohnalkova, Alice; Moore, Dean A.; Nachimuthu, Ponnusamy; Reed, Samantha B.; Fredrickson, Jim K.

2011-12-13

466

Methods of forming steel  

SciTech Connect

In one aspect, the invention encompasses a method of forming a steel. A metallic glass is formed and at least a portion of the glass is converted to a crystalline steel material having a nanocrystalline scale grain size. In another aspect, the invention encompasses another method of forming a steel. A molten alloy is formed and cooled the alloy at a rate which forms a metallic glass. The metallic glass is devitrified to convert the glass to a crystalline steel material having a nanocrystalline scale grain size. In yet another aspect, the invention encompasses another method of forming a steel. A first metallic glass steel substrate is provided, and a molten alloy is formed over the first metallic glass steel substrate to heat and devitrify at least some of the underlying metallic glass of the substrate.

Branagan, Daniel J. (Iona, ID); Burch, Joseph V. (Shelley, ID)

2001-01-01

467

Preparation of Soft Manganese Ferrite and Inventional of its Magnetic Properties and Mn55 Nuclear Magnetic Resonance  

NASA Astrophysics Data System (ADS)

In this study, Mn-ferrite has been prepared with nominal formula of MnFe2O4, using the dry conventional ceramic method. The raw materials were Mobarakeh steel company modified domestic iron oxide and Merk manganese oxide. XRD patterns of the prepared samples show that they are single phase. Magnetic measurements have been performed on the toroidal samples sintered in different temperatures, using a hystograph unit MPG100D model. The results of measurements show that optimum formation pressures to obtain maximum relative magnetic permeability and hystersis. We report here the observation of the Mn55 nuclear magnetic resonance associated with the Mn2 + ion in the ferromagnetic spinel MnFe2O4 also.

Soleimani, R.; Soleimani, M.; Gheisari Godarzi, M.; Askari, A.

2011-08-01