Iron-Speciation Control of Chalcopyrite Dissolution from a Carbonatite Derived Concentrate with Acidic Ferric Sulphate Media

The mechanisms involved in the dissolution of chalcopyrite from a carbonatite concentrate in a ferric sulphate solution at pH 1.0, 1.5 and 1.8, and temperatures 25 °C and 50 °C were investigated. Contrary to expectations and thermodynamic predictions according to which low pH would favour high Cu dissolution, the opposite was observed. The dissolution was also highly correlated to the temperature. CuFeS2 phase dissolution produced intermediate Cu rich phases: CuS, Cu2S and Cu5FeS4, which appeared to envelop CuFeS2. Thermodynamic prediction revealed CuS to be refractory and could hinder dissolution. CuFeS2 phase solid-state dissolution process was further discussed. Free Fe3+ and its complexes (Fe(HSO4)2+, Fe(SO4)2– and FeSO4+ were responsible for Cu dissolution, which increased with increasing pH and temperature. The dissolution improved at pH 1.8 rather than 1.0 due to the increase of (Fe(HSO4)2+, Fe(SO4)2– and FeSO4+, which were also the predominating species at a higher temperature. The fast and linear first dissolution stage was attributed to the combined effect of Fe3+ and its complex (Fe(HSO4)2+, while Fe(SO4)2– was the main species for the second Cu dissolution stage characterised by a slow rate.

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The Influence of Ocean Acidification and Warming on DMSP & DMS in New Zealand Coastal Water

Atmosphere ◽

10.3390/atmos12020181 ◽

2021 ◽

Vol 12 (2) ◽

pp. 181

Author(s):

Alexia D. Saint-Macary ◽

Neill Barr ◽

Evelyn Armstrong ◽

Karl Safi ◽

Andrew Marriner ◽

...

Keyword(s):

Ocean Acidification ◽

Coastal Water ◽

Phytoplankton Community ◽

Dimethyl Sulfide ◽

Temperature Treatment ◽

Low Ph ◽

Trace Gas ◽

Mesocosm Experiments ◽

Future Warming ◽

Higher Temperature

The cycling of the trace gas dimethyl sulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) may be affected by future ocean acidification and warming. DMSP and DMS concentrations were monitored over 20-days in four mesocosm experiments in which the temperature and pH of coastal water were manipulated to projected values for the year 2100 and 2150. This had no effect on DMSP in the two-initial nutrient-depleted experiments; however, in the two nutrient-amended experiments, warmer temperature combined with lower pH had a more significant effect on DMSP & DMS concentrations than lower pH alone. Overall, this indicates that future warming may have greater influence on DMS production than ocean acidification. The observed reduction in DMSP at warmer temperatures was associated with changes in phytoplankton community and in particular with small flagellate biomass. A small decrease in DMS concentration was measured in the treatments relative to other studies, from −2% in the nutrient-amended low pH treatment to −16% in the year 2150 pH and temperature conditions. Temporal variation was also observed with DMS concentration increasing earlier in the higher temperature treatment. Nutrient availability and community composition should be considered in models of future DMS.

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Joining of Ti3SiC2 with Ti–6Al–4V Alloy

Journal of Materials Research ◽

10.1557/jmr.2002.0010 ◽

2002 ◽

Vol 17 (1) ◽

pp. 52-59 ◽

Cited By ~ 33

Author(s):

N.F. Gao ◽

Y. Miyamoto

Keyword(s):

Solid State ◽

Rate Constant ◽

Liquid State ◽

Parabolic Rate Constant ◽

Diffusion Path ◽

Solid State Diffusion ◽

Diffusion Controlled ◽

State Diffusion ◽

Rate Controlled ◽

Higher Temperature

The joining of a Ti3SiC2 ceramic with a Ti–6Al–4V alloy was carried out at the temperature range of 1200–1400 °C for 15 min to 4 h in a vacuum. The total diffusion path of joining was determined to be Ti3SiC2/Ti5Si3Cx/Ti5Si3Cx + TiCx/TiCx/Ti. The reaction was rate controlled by the solid-state diffusion below 1350 °C and turned to the liquid-state diffusion controlled with a dramatic increase of parabolic rate constant Kp when the temperature exceeded 1350 °C. The TiCx tended to grow at the boundarywith the Ti–6Al–4V alloy at a higher temperature and longer holding time. TheTi3SiC2/Ti–6Al–4V joint is expected to be applied to implant materials.

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Uniqueness and Challenges of Sintered Silver as a Bonded Interface Material†

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/hitec-wa23 ◽

2014 ◽

Vol 2014 (HITEC) ◽

pp. 000178-000187

Author(s):

A. A. Wereszczak ◽

Z. Liang ◽

M. K. Ferber ◽

L. D. Marlino

Keyword(s):

Solid State ◽

Bond Strength ◽

New Technology ◽

State Process ◽

Bonded Interface ◽

Temperature Capability ◽

Thermally Conductive ◽

Higher Temperature ◽

Sintered Ag ◽

Sintered Silver

There are numerous attributes of sintered silver (Ag) as a bonded interface between die and substrate or even between substrate and heat sink in power devices. This is attested to by the relatively large number of studies devoted to it the last several years. Sintered silver potentially has a high temperature capability, high electrical and thermal conductivities, its microstructure is in equilibrium, it could predictably respond linearly elastically during thermal cycling, and the time-dependent pore coalescence and pore growth that exists with solders is apparently minimal or even nonexistent. But sintered silver bonding is a relatively new technology and solid-state sintering science and its application can be unfamiliar to solder/bonding practitioners. There are at least five different aspects of it compared to solder bonding and those are overviewed here based on the authors' experience with Ag-sintering over the last several years. For sintered-Ag interconnect bonding: it is a solid-state process (i.e., no melting); its bond strength is affected by the topography of the mating surfaces; concurrent pressure application during processing can improve bond strength; issues associated with the paste's organic binder burnout and exhaust can arise depending on the interconnect size; and porosity is indigenous to its bulk microstructure requiring its consideration and possible management. Increased understanding of these unique characteristics will help advance employment of sintered-Ag technology and the exploitation of its attributes for fabricating more reliable, higher-temperature- capable, and more thermally conductive power electronic modules.

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Temperature relevant performance and calibration of spin-valve sensor

Sensor Review ◽

10.1108/sr-01-2019-0005 ◽

2019 ◽

Vol 39 (6) ◽

pp. 881-886

Author(s):

Huachen Zhu ◽

Zhenghong Qian ◽

Jiaofeng Zhang ◽

Yucheng Sun ◽

Ru Bai ◽

...

Keyword(s):

Spin Valve ◽

Temperature Stability ◽

Lower Sensitivity ◽

Temperature Drift ◽

Content Type ◽

Temperature Changes ◽

Drift Model ◽

Higher Temperature ◽

Highly Correlated ◽

The Relationship

Purpose It has been noted that the spin-valve sensor exhibits lower sensitivity with higher temperature because of the variation of GMR ratio, which could lead to the measurement error in applications where working temperature changes largely over seasons or times. This paper aims to investigate and compensate the temperature effect of the spin-valve sensor. Design/methodology/approach A spin-valve sensor is fabricated based on microelectronic process, and its temperature relevant properties are investigated, in which the transfer curves are acquired within a temperature range of −50°C to 125°C with a Helmholtz coil and temperature chamber. Findings It is found that the sensitivity of spin-valve sensor decreases with temperature linearly, where the temperature coefficient is calculated at −0.25 %/°C. The relationship between sensitivity of spin-valve sensor and temperature is well-modeled. Originality/value The temperature drift model of the spin-valve sensor’s sensitivity is highly correlated with tested results, which could be used to compensate the temperature influence on the sensor output. A self-compensation sensor system is proposed and built based on the expression modeled for the temperature dependence of the sensor, which exhibits a great improvement on temperature stability.

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Effects of Annealing on Phase Formation and Critical Current Density of Dip-Coated Tl0.5Pb0.5 Sr1.8Yb0.2CaCu2O7 Superconducting Tapes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.517.13 ◽

2006 ◽

Vol 517 ◽

pp. 13-16

Author(s):

Faizah Md. Salleh ◽

Ahmad K. Yahya ◽

M.H. Ismail ◽

M.H. Jumali

Keyword(s):

Solid State ◽

Magnetic Fields ◽

Critical Current Density ◽

Phase Formation ◽

Current Density ◽

Weak Links ◽

Superconducting Tapes ◽

General Increase ◽

Higher Temperature ◽

Conventional Solid State Synthesis

In this study, single-core and multi-core Tl1212 tapes were fabricated from Tl-1212 superconducting powder of Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 starting composition derived by conventional solid state synthesis. Single core tapes showed maximum Jc and enhanced 1212 phase formation were achieved for tapes annealed at a higher temperature for a longer duration. Multi core tapes showed a general increase in Ic and Jc with the number of tapes core. The highest Jc of 521 A/cm2 was observed for the 4-core tapes annealed at 870 °C for 90 minutes. The initial drastic drop of the tapes Jc in low magnetic fields (≤1T) indicates limitation on tapes performance by weak links. The low Jc of the tapes may be due to the lack of texture in the tapes core as revealed by SEM.

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Alloys for Semi-Solid Processing

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.192-193.16 ◽

2012 ◽

Vol 192-193 ◽

pp. 16-27 ◽

Cited By ~ 19

Author(s):

Helen V. Atkinson

Keyword(s):

Alloy Design ◽

Point Of View ◽

Cast Irons ◽

Thermodynamic Prediction ◽

Key Issues ◽

Higher Temperature ◽

Semi Solid ◽

Alloy Systems

The main alloys which have been semi-solid processed commercially are based on aluminium (particularly the cast compositions) and magnesium. There is a strong drive to broaden the range of alloys to the wrought compositions for aluminium, more creep-resistant magnesium recipes and to higher temperature alloys such as those based on copper, steels, stellites and cast irons. This paper will summarise the issues with such development including the scientific and practical issues for alloy design and the thermodynamic prediction of alloys suitable for semi-solid processing. After an initial introduction to semi-solid processing routes, the most important alloy systems for semi-solid processing from a development point of view (aluminium, magnesium, steels and composites- including nanocomposites) will be discussed. The key issues of alloy design specifically for semi-solid processing will be drawn out through the text.

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The combined effect of mechanical and thermal energy on the solid-state formation of NiFe2O4 from the system 2NiCO3·3Ni(OH)2·4H2O–FeC2O4·2H2O

Thermochimica Acta ◽

10.1016/j.tca.2007.11.025 ◽

2008 ◽

Vol 469 (1-2) ◽

pp. 86-90 ◽

Cited By ~ 8

Author(s):

Vittorio Berbenni ◽

Chiara Milanese ◽

Giovanna Bruni ◽

Amedeo Marini

Keyword(s):

Solid State ◽

State Formation ◽

Thermal Energy ◽

Combined Effect

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Investigation on the Effect of Mn on the Dielectric Properties of Ba0.4Sr0.6TiO3/MgAl2O4/MgO Composite Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.421-422.65 ◽

2009 ◽

Vol 421-422 ◽

pp. 65-68

Author(s):

Jing Ji Zhang ◽

Ji Wei Zhai ◽

Ming Wei Zhang ◽

Xi Yao

Keyword(s):

Dielectric Properties ◽

Solid State ◽

Solid State Reactions ◽

Composite Ceramics ◽

Higher Temperature ◽

Lower Temperature ◽

Three Phases

xMnCO3–(1–x)[70wt% (10wt% MgO–90wt% Ba0.4Sr0.6TiO3)–30wt% MgAl2O4] (where x=0.0, 0.5, 1.0, 2.0, 5.0 and 10.0wt%) composite ceramics have been prepared through the solid-state reactions. Three phases, corresponding to the Ba0.4Sr0.6TiO3(BST), MgAl2O4(MA) and MgO phases, are clearly visible in the composite ceramics. The permittivity peak is initially enhanced and shifted toward a higher temperature and then suppressed, shifted toward a lower temperature. Meanwhile, the tunability (calculated by [ε(E0)−ε(E)]/ε(E0)) is also initially improved and then decreased by doping MnCO3.

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Composition and Distribution of Pythium Communities in Wheat Fields in Eastern Washington State

Phytopathology ◽

10.1094/phyto.2003.93.7.867 ◽

2003 ◽

Vol 93 (7) ◽

pp. 867-873 ◽

Cited By ~ 45

Author(s):

T. C. Paulitz ◽

K. Adams

Keyword(s):

Soil Type ◽

Low Frequency ◽

Hierarchical Cluster ◽

Annual Precipitation ◽

Frequency Distributions ◽

Higher Temperature ◽

Highly Correlated ◽

Eastern Washington ◽

The Relationship ◽

Average Annual Precipitation

Pythium spp. were isolated from a mixture of soil and roots collected from 80 wheat fields in eastern Washington in the summer of 2000 from an area encompassing approximately 27,000 km2. These sites covered a range of soil textures (coarse to fine, silty loess), average annual precipitation (200 to 600 mm), and average annual temperatures (7 to 11°C). Soil type and annual precipitation run in an east-west gradient, while temperature has a north-south gradient. Species were identified using classical methods and by sequencing the internal transcribed spacer (ITS)-1 region of the rDNA and comparing these sequences to a database from a worldwide collection of Pythium spp. The species with the highest frequency of occurrence among all the sites were P. abappressorium sp. nov. (A) (50%), P. rostratum (R) (40%), P. debaryanum (D) (37.5%), P. heterothallicum (H) (33.7%), P.oligandrum (O) (31.2%), an unidentified P. sp. (aff. echinulatum) (E) (25%), and P. ultimum (U) (18%). P. intermedium, P. irregulare, P. paroecandrum, P. sylvaticum, P. dissimile, and P. dissoticum were isolated at a low frequency. From one to six species were isolated at each site, and there were 46 different species combinations detected. The species presence/absence data from all sites were analyzed with Jaccard's similarity coefficient hierarchical cluster analysis. Six communities were identified (species within each community designation in order of frequency among the sites within the community)-AD, AOU, AR, DEH, HE, and RU. In general, P. abappressorium was evenly distributed over all zones. AOU was more prevalent in zones with lower precipitation and coarser soil, while DEH and HE were associated with zones with higher precipitation and finer-textured soils on the basis of comparison of frequency distributions with the expected distribution over all the sites. The RU community was more prevalent in higher temperature zones. Canonical correspondence analysis was performed to examine the relationship between species and environmental variables. Soil type and precipitation were highly correlated with each other and with axis 1, which separated P. ultimum and P. abappressorium (lower variable values) from P. heterothallicum (higher variable values). Axis 2 and 3 were most correlated with temperature, and these axes separated P. oligandrum (higher value) from P. debaryanum (lower value) and P. ultimum-P. rostratum from the other species. The results suggest that Pythium species composition, distributions, and associations on a given crop may be influenced by environmental factors at a mesoscale level (100 to 1,000,000 ha).

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