Electrochemical Phase Diagrams for the Fe/S/H2O System under Geothermal Conditions

1985 ◽  
Vol 38 (5) ◽  
pp. 643 ◽  
Author(s):  
BG Pound ◽  
GA Wright ◽  
RM Sharp
Keyword(s):  
New Zealand ◽  
Phase Diagrams ◽  
Elevated Temperatures ◽  
Corrosion Products ◽  
Ferrous Alloys ◽  
Temperature Range ◽  
General Terms ◽  
Geothermal Fluids ◽  
Region Of Stability ◽  
Regions Of Stability

Previously published electrochemical phase (potential-pH) diagrams for the Fe/S/H2O system at elevated temperatures are assessed. It is concluded that the potential-pH equations derived by Biernat and Robins1 can be used to provide reliable diagrams over the temperature range 298-573 K. These equations were used to derive a set of diagrams relevant to geothermal fluids in general terms, so that the corrosion products of iron and ferrous alloys immersed in these fluids may be predicted. In addition, diagrams are presented for geothermal fluids in the Broadlands and Wairakei fields in New Zealand. The significant changes in the E-pH diagrams as the temperature increases over the range 298-573 K are that the region of stability for Fe(OH)3- widens and the regions of stability for FeS2 and Fe3O4 and, at higher temperatures, FeS, shrink in size.

Dynamic Indentation of Copper and an Aluminium Alloy with a Conical Projectile at Elevated Temperatures

1965 ◽  
Vol 180 (1) ◽  
pp. 285-294 ◽  
Author(s):  
F. U. Mahtab ◽  
W. Johnson ◽  
R. A. C. Slater
Keyword(s):  
Strain Rate ◽  
Aluminium Alloy ◽  
Temperature Coefficient ◽  
Elevated Temperatures ◽  
Dynamic Pressure ◽  
Pure Metal ◽  
Dynamic Indentation ◽  
Strain Rate Effects ◽  
Dynamic Temperature ◽  
Temperature Range

The dynamic indentation of copper (B.S. 1433) and an aluminium alloy (B.S. 1476 HE 10) has been investigated, using cylindro-conical projectiles fired from an air-actuated gun. The experiments were performed with impact velocities varying between 1000 and 2500 in/s and at elevated temperatures up to 600°C for the copper and 550°C for the aluminium alloy. The magnitude of the corresponding range of mean strain rate was then 103-104/s, depending upon the material; impact velocity and temperature (see Appendix I). For the range of impact velocities investigated no consequential transition temperature † was encountered. The dynamic temperature coefficient† thus remained constant throughout the test temperature range for each material. This dynamic temperature coefficient was found to be equal to the static temperature coefficient corresponding to the sub-transitional temperature range for the respective materials. The mean effective dynamic indentation pressure is shown to decrease with temperature but the ratio of this dynamic pressure to the static indentation pressure increases with temperature. Strain rate effects for both materials were negligible for sub-transitional temperatures but become important at super-transitional temperatures. It was observed that the parameters on which the strain rate effect depends are in some way related to the absolute melting point of a pure metal.

Antiferromagnetic exchange in triclinic crystals of tetra-u-benzoato- bits (4-methylquinoline) dicobalt II

1978 ◽  
Vol 360 (1701) ◽  
pp. 191-210 ◽  
Keyword(s):  
Cobalt Complex ◽  
Preceding Paper ◽  
Transverse Magnetic ◽  
Antiferromagnetic Coupling ◽  
Temperature Range ◽  
General Terms ◽  
Carboxylate Groups ◽  
A New Technique ◽  
Unambiguous Conclusion ◽  
Good Agreement

The magnetic susceptibilities of tetra- u -benzoato- bis (4-methylquinoline) dicobalt ii have been measured and interpreted within the theoretical model described in the preceding paper. Crystals of the title complex are triclinic, a circumstance which has lead to the development of a new technique for the measurement of triclinic crystal susceptibilities using a Faraday balance. The technique is discussed in general terms and is applicable with Faraday equipment employing either longitudinal or, as here, transverse magnetic fields. The magnetic tensor for this binuclear cobalt complex has been determined throughout the temperature range 20- 300 K. Good agreement between these results and those calculated from the quantum mechanical model have been obtained in the temperature range 90-300 K. At lower temperatures, a probable small paramagnetic impurity prevents useful theoretical treatm ent. There emerges an unambiguous conclusion that the antiferromagnetic coupling between the cobalt atoms is almost completely determined by interaction between metal xy orbitals, presumably via a superexchange process involving the delocalized n bonding framework of the bridging carboxylate groups.

scholarly journals Development of Creep-Resistant, Alumina-Forming Ferrous Alloys for High-Temperature Structural Use

2018 ◽  
Author(s):  
Y. Yamamoto ◽  
M. P. Brady ◽  
G. Muralidharan ◽  
B. A. Pint ◽  
P. J. Maziasz ◽  
...  
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Extreme Environments ◽  
Alloy Design ◽  
Austenitic Steels ◽  
Strength Development ◽  
Second Phase ◽  
Ferrous Alloys ◽  
Steel Alloys ◽  
Structural Applications

This paper overviews recent advances in developing novel alloy design concepts of creep-resistant, alumina-forming Fe-base alloys, including both ferritic and austenitic steels, for high-temperature structural applications in fossil-fired power generation systems. Protective, external alumina-scales offer improved oxidation resistance compared to chromia-scales in steam-containing environments at elevated temperatures. Alloy design utilizes computational thermodynamic tools with compositional guidelines based on experimental results accumulated in the last decade, along with design and control of the second-phase precipitates to maximize high-temperature strengths. The alloys developed to date, including ferritic (Fe-Cr-Al-Nb-W base) and austenitic (Fe-Cr-Ni-Al-Nb base) alloys, successfully incorporated the balanced properties of steam/water vapor-oxidation and/or ash-corrosion resistance and improved creep strength. Development of cast alumina-forming austenitic (AFA) stainless steel alloys is also in progress with successful improvement of higher temperature capability targeting up to ∼1100°C. Current alloy design approach and developmental efforts with guidance of computational tools were found to be beneficial for further development of the new heat resistant steel alloys for various extreme environments.

scholarly journals Niue's Relationship of Free Association with new Zealand

1999 ◽  
Vol 30 (2) ◽  
pp. 589 ◽  
Author(s):  
Alison Quentin-Baxter
Keyword(s):  
New Zealand ◽  
Free Association ◽  
General Terms ◽  
Relationship Of ◽  
The Relationship ◽  
Administrative Assistance

This article provides an account of the relationship between Niue and New Zealand. Because Niue is both a self-governing state and one who has a relationship of free association with New Zealand, Niue's government makeup is both constitutional and contractual. The article discusses the principles of Niue's free association status with New Zealand in light of its constitutional makeup. The nature of the relationship between New Zealand and Niue is discussed in general terms, and the principles of economic and administrative assistance from New Zealand is explored in greater detail.  

scholarly journals The Effect of Nanostructure Modification on the Silicate Binder on Its Binding Characteristics and Functional Properties

2014 ◽  
Vol 59 (3) ◽  
pp. 1033-1036 ◽  
Author(s):  
I. Izdebska-Szanda ◽  
A. Baliński ◽  
M. Angrecki ◽  
A. Palma
Keyword(s):  
Chemical Modification ◽  
Sodium Silicate ◽  
Functional Properties ◽  
Elevated Temperatures ◽  
Technological Properties ◽  
Ferrous Alloys ◽  
Silicate Binder ◽  
Binding Characteristics ◽  
The Impact

Abstract A method for the chemical modification of silicate binder (hydrated sodium silicate) affecting the distribution of its nanostructure elements was disclosed. The effect of silicate binder modification on the resulting technological properties of moulding sands, determined under standard conditions and at elevated temperatures in the range from 1000C to 9000C, was discussed. Modification of this type is done on inorganic binders in order to reduce their unfavourable functional properties. It is particularly important when moulding sands with the silicate binder are used for casting of low-melting alloys. Therefore special attention was paid to the impact that modification of inorganic binders may have on the knocking out properties of sands prepared with these binders, when they are used in the process of casting non-ferrous alloys.

scholarly journals Characterizing a thermostable Cas9 for bacterial genome editing and silencing

2017 ◽  
Author(s):  
Ioannis Mougiakos ◽  
Prarthana Mohanraju ◽  
Elleke F. Bosma ◽  
Valentijn Vrouwe ◽  
Max Finger Bou ◽  
...  
Keyword(s):  
Genome Editing ◽  
Genome Engineering ◽  
Gene Deletion ◽  
Elevated Temperatures ◽  
Bacterial Genome ◽  
Thermophilic Bacterium ◽  
Geobacillus Thermodenitrificans ◽  
Temperature Range ◽  
Fundamental Research

AbstractCRISPR-Cas9 based genome engineering tools have revolutionized fundamental research and biotechnological exploitation of both eukaryotes and prokaryotes. However, the mesophilic nature of the established Cas9 systems does not allow for applications that require enhanced stability, including engineering at elevated temperatures. Here, we identify and characterize ThermoCas9: an RNA-guided DNA-endonuclease from the thermophilic bacterium Geobacillus thermodenitrificans T12. We show that ThermoCas9 is active in vitro between 20°C and 70°C, a temperature range much broader than that of the currently used Cas9 orthologues. Additionally, we demonstrate that ThermoCas9 activity at elevated temperatures is strongly associated with the structure of the employed sgRNA. Subsequently, we develop ThermoCas9-based engineering tools for gene deletion and transcriptional silencing at 55°C in Bacillus smithii and for gene deletion at 37°C in Pseudomonas putida. Altogether, our findings provide fundamental insights into a thermophilic CRISPR-Cas family member and establish the first Cas9-based bacterial genome editing and silencing tool with a broad temperature range.

scholarly journals Biology and survival of broom corn millet (Panicum miliaceum) seed

2011 ◽  
Vol 64 ◽  
pp. 142-148 ◽  
Author(s):  
T.K. James ◽  
A. Rahman ◽  
C.R. McGill ◽  
P.D. Trivedi
Keyword(s):  
Zea Mays ◽  
New Zealand ◽  
Seed Germination ◽  
Sweet Corn ◽  
Management Control ◽  
Panicum Miliaceum ◽  
Wild Type ◽  
Temperature Range ◽  
Control Options ◽  
Millet Seed

The wild type of broom corn millet (Panicum miliaceum) is a serious emerging weed currently prevalent in New Zealand sweet corn (Zea mays) crops This study shows its seed is nearly twice the weight of other common grass weeds and can germinate in the temperature range 1634C with 50 germination at 26C and greatest germination occurring at 31C At 15C it took 8 days for seedlings to emerge but required only 4 days at 25C Seed was able to emerge from depths of up to 170 mm in a range of soils Experiments showed that broom corn millet seed can persist in the soil for longer than 2 years in the field but is killed in silage stack and bales Immersion in stock effluent for up to three months reduced seed germination to less than 40 These characteristics are discussed in relation to herbicide and management control options for this weed

CMOS Circuits on Silicon Carbide for High Temperature Operation

2014 ◽  
Vol 1693 ◽  
Author(s):  
David T. Clark ◽  
Robin F. Thompson ◽  
Aled E. Murphy ◽  
David A. Smith ◽  
Ewan P. Ramsay ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Wide Temperature Range ◽  
Integrated Circuit ◽  
Elevated Temperatures ◽  
Logic Circuits ◽  
Digital Logic ◽  
Cmos Integrated Circuit ◽  
Temperature Range ◽  
Simple Logic

ABSTRACTWe present the characteristics of a high temperature CMOS integrated circuit process based on 4H silicon carbide designed to operate at temperatures beyond 300°C. N-channel and P-channel transistor characteristics at room and elevated temperatures are presented. Both channel types show the expected low values of field effect mobility well known in SiC MOSFETS. However the performance achieved is easily capable of exploitation in CMOS digital logic circuits and certain analogue circuits, over a wide temperature range.Data is also presented for the performance of digital logic demonstrator circuits, in particular a 4 to 1 analogue multiplexer and a configurable timer operating over a wide temperature range. Devices are packaged in high temperature ceramic dual in line (DIL) packages, which are capable of greater than 300°C operation. A high temperature “micro-oven” system has been designed and built to enable testing and stressing of units assembled in these package types. This system heats a group of devices together to temperatures of up to 300°C while keeping the electrical connections at much lower temperatures. In addition, long term reliability data for some structures such as contact chains to n-type and p-type SiC and simple logic circuits is summarized.

Phase diagrams

2021 ◽  
pp. 19-29
Author(s):  
Adrian P Sutton
Keyword(s):  
Free Energy ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Full Range ◽  
Phase Rule ◽  
Intermediate Phases ◽  
Ordered Alloys ◽  
Regions Of Stability ◽  
Liquid States

Temperature-composition phase diagrams are introduced as maps of the regions of stability of binary systems at constant pressure, usually atmospheric pressure at sea level. Their construction is based on minimisation of the Gibbs free energy as a function of composition at a given temperature. The simple case of miscibility in the solid and liquid states over the full range of composition is discussed first. Eutectic and peritectic phase diagrams result from limited miscibility in the solid state. Intermediate phases, or ordered alloys, usually occur in narrow ranges of composition in phase diagrams, and this is also explained in terms of free energy composition curves. Each phase diagram is shown to obey the phase rule discussed in the previous chapter.

Electron Transport Features in Heterostructures 3C-SiC(n)/Si(p) at the Elevated Temperatures

2013 ◽  
Vol 740-742 ◽  
pp. 498-501
Author(s):  
A.V. Afanasyev ◽  
V.A. Ilyin ◽  
V.V. Luchinin ◽  
A.S. Petrov
Keyword(s):  
Electron Transport ◽  
Charge Transport ◽  
Wide Temperature Range ◽  
Silicon Substrate ◽  
Elevated Temperatures ◽  
Reverse Current ◽  
Current Generation ◽  
Temperature Range ◽  
Working Temperature ◽  
Transport Diffusion

3C-SiC (n) / Si (p) heterostructures were obtained and investigated in a wide temperature range. It was shown, the main mechanisms of charge transport diffusion and recombination. The properties of silicon substrate were determining the working temperature range of investigated diodes. Therefore the rectifying properties of 3С-SiC(n)/Si(p) diodes were stable only up to 473 K. Two sites with different activation energies were observed on the Jrev(1/T) curves at fixed voltage: 0,32 eV which, characterized states on the SiC/Si interface, Е2 ≈ 0,55 eV which corresponds to the middle of silicon bandgap and defines existence of reverse current generation component.

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