scholarly journals Structure and nature of ice XIX

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christoph G. Salzmann ◽  
John S. Loveday ◽  
Alexander Rosu-Finsen ◽  
Craig L. Bull
Keyword(s):  
Phase Transition ◽  
Materials Science ◽  
Water Molecules ◽  
Orientational Disorder ◽  
Structural Distortions ◽  
Scientific Disciplines ◽  
Wide Range ◽  
Alternative Type ◽  
In Situ Neutron Diffraction

AbstractIce is a material of fundamental importance for a wide range of scientific disciplines including physics, chemistry, and biology, as well as space and materials science. A well-known feature of its phase diagram is that high-temperature phases of ice with orientational disorder of the hydrogen-bonded water molecules undergo phase transitions to their ordered counterparts upon cooling. Here, we present an example where this trend is broken. Instead, hydrochloric-acid-doped ice VI undergoes an alternative type of phase transition upon cooling at high pressure as the orientationally disordered ice remains disordered but undergoes structural distortions. As seen with in-situ neutron diffraction, the resulting phase of ice, ice XIX, forms through a Pbcn-type distortion which includes the tilting and squishing of hexameric clusters. This type of phase transition may provide an explanation for previously observed ferroelectric signatures in dielectric spectroscopy of ice VI and could be relevant for other icy materials.

scholarly journals Effect of Sintering Temperature on Metal-Insulator Phase Transition in La1-xCaxMnO3 Perovskites

2020 ◽  
Vol 2 (1) ◽  
pp. 37-42
Author(s):  
Arunachalam M ◽  
Thamilmaran P ◽  
Sakthipandi K
Keyword(s):  
Phase Transition ◽  
Bulk Modulus ◽  
Sintering Temperature ◽  
Magnetic Sensors ◽  
Temperature Dependent ◽  
Metal Insulator ◽  
Wide Range ◽  
Different Temperatures ◽  
Insulator Phase Transition

Lanthanum calcium based perovskites are found to be advantageous for the possible applications in magnetic sensors/reading heads, cathodes in solid oxide fuel cells, and frequency switching devices. In the present investigation La0.3Ca0.7MnO3 perovskites were synthesised through solid state reaction and sintered at four different temperatures such as 900, 1000, 1100 and 1200˚ C. X-ray powder diffraction pattern confirms that the prepared La0.3Ca0.7MnO3 perovskites have orthorhombic structure with Pnma space group. Ultrasonic in-situ measurements have been carried out on the La0.3Ca0.7MnO3 perovskites over wide range of temperature and elastic constants such as bulk modulus of the prepared La0.3Ca0.7MnO3 perovskites was obtained as function of temperature. The temperature-dependent bulk modulus has shown an interesting anomaly at the metal-insulator phase transition. The metal insulator transition temperature derived from temperature-dependent bulk modulus increases from temperature 352˚ C to 367˚ C with the increase of sintering temperature from 900 to 1200˚ C.

scholarly journals TMAO regulates the rigidity of kinesin-propelled microtubules

2021 ◽  
Author(s):  
Tasrina Munmun ◽  
Arif Md. Rashedul Kabir ◽  
Kazuki Sada ◽  
Akira Kakugo
Keyword(s):  
Deep Sea ◽  
Materials Science ◽  
Persistence Length ◽  
Simple Strategy ◽  
Biomolecular Motors ◽  
Wide Range

AbstractWe demonstrate that the rigidity of the microtubules (MTs), propelled by kinesins in an in vitro gliding assay, can be modulated using the deep-sea osmolyte trimethylamine N-oxide (TMAO). By varying the concentration of TMAO in the gliding assay, the rigidity of the MTs is modulated over a wide range. By employing this approach, we are able to reduce the persistence length of MTs, a measure of MT rigidity, ∼8 fold using TMAO of the concentration of 1.5 M. The rigidity of gliding MTs can be restored by eliminating the TMAO from the gliding assay. This work offers a simple strategy to regulate the rigidity of kinesin-propelled MTs in situ and would widen the applications of biomolecular motors in nanotechnology, materials science, and bioengineering.

In Situ Neutron Diffraction Studies of LiCe(WO4)2 Polymorphs: Phase Transition and Structure–Property Correlation

2018 ◽  
Vol 123 (2) ◽  
pp. 1041-1049 ◽  
Author(s):  
Archana K. Munirathnappa ◽  
Debasmita Dwibedi ◽  
James Hester ◽  
Prabeer Barpanda ◽  
Diptikanta Swain ◽  
...  
Keyword(s):  
Phase Transition ◽  
Neutron Diffraction ◽  
Structure Property ◽  
Property Correlation ◽  
In Situ Neutron Diffraction

scholarly journals Kinetics of deuteration of the Pd0.772Ag0.228 alloy with α/β phase transition by in-situ neutron diffraction

2019 ◽  
Vol 790 ◽  
pp. 502-508 ◽  
Author(s):  
Michele Catti ◽  
Oscar Fabelo ◽  
Alessandra Filabozzi ◽  
Antonino Pietropaolo ◽  
Alessia Santucci ◽  
...  
Keyword(s):  
Phase Transition ◽  
Neutron Diffraction ◽  
Β Phase ◽  
In Situ Neutron Diffraction ◽  
Kinetics Of

Performance and characteristics of the BILBY time-of-flight small-angle neutron scattering instrument

2019 ◽  
Vol 52 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Anna Sokolova ◽  
Andrew E. Whitten ◽  
Liliana de Campo ◽  
Jason Christoforidis ◽  
Andrew Eltobaji ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Materials Science ◽  
Time Of Flight ◽  
Nuclear Science ◽  
Scientific Disciplines ◽  
Wide Range ◽  
Wavelength Resolution ◽  
Reference Samples

BILBY is a recently constructed and commissioned time-of-flight small-angle neutron scattering instrument, operated by the Australian Centre for Neutron Scattering at the Australian Nuclear Science and Technology Organisation (ANSTO). BILBY provides a wide accessible q range (q ≃ 1.0 × 10−3 Å−1 to ∼1.8 Å−1) and variable wavelength resolution (Δλ/λ ≃ 3–30%) to complement the other small-angle and ultra-small-angle neutron scattering capabilities available at ANSTO. Since its construction, BILBY has been used to study samples from a wide range of scientific disciplines, including biology, chemistry, physics and materials science. This article describes the BILBY design and components, and shows data collected from a number of reference samples.

Phase transition and ordering behavior of ternary Ti–Al–Mo alloys using in-situ neutron diffraction

2011 ◽  
Vol 102 (6) ◽  
pp. 697-702 ◽  
Author(s):  
Saurabh Kabra ◽  
Kun Yan ◽  
Svea Mayer ◽  
Thomas Schmoelzer ◽  
Mark Reid ◽  
...  
Keyword(s):  
Phase Transition ◽  
Neutron Diffraction ◽  
In Situ Neutron Diffraction

Self-Lubrication of Machining Tools in Dry via In-situ Formed Tribofilms

2005 ◽  
Vol 890 ◽  
Author(s):  
Tatsuhiko Aizawa ◽  
Shigeo Yamamoto ◽  
Taro Sumitomo
Keyword(s):  
Materials Science ◽  
Protective Coatings ◽  
Cutting Speed ◽  
Green Manufacturing ◽  
Dry Machining ◽  
Wide Range ◽  
In Situ Formation ◽  
Green Manufacturing Technology ◽  
Turning Test

ABSTRACTGreen manufacturing technology has become a significant innovative keyword to reduce the environmental burden and CO2 emission at the stage of manufacturing and production. In daily operations by machining, huge amount of lubricating oils and cleansing agents is wasted so that dry machining technology provides us a way to completely reduce these wastes. Among several candidates, self-lubrication via in-situ formation of lubricious oxide films is accommodated to protective coatings in order to attain low friction and wear state even at higher cutting speed range. Materials science of in-situ formed lubricious oxide tribofilms is stated with consideration of accommodation mechanism via the chlorine implantation. Mechanical characterization is made for evaluation on elasto-plastic deformation of lubricious oxides. Turning test is employed to evaluate dry machinability of various tools for wide range of cutting speed. Self-lubrication in dry machining is described both for bare WC and TiCN-coated WC tools with and without chlorine implantation. Precise microstructure analyses are made by using the laser microscope, EDS and XPS. In-situ formation of lubricous oxides proves that self-lubrication process takes place even in dry machining to reduce the flank wear and friction coefficient.

Aberration correction: zooming out to overview

2009 ◽  
Vol 367 (1903) ◽  
pp. 3859-3870 ◽  
Author(s):  
A. Howie
Keyword(s):  
Materials Science ◽  
Complex Structure ◽  
Chromatic Aberration ◽  
Aberration Correction ◽  
Contrast Imaging ◽  
Atomic Column ◽  
Wide Range ◽  
The Many

In the structural characterization of thin specimens by projection (atomic column) imaging, the revolutionary development of aberration-corrected electron microscopy has already brought significant improvements not only in spatial resolution but also in improved image contrast. Some highlights from the symposium are summarized. Despite the purchasing and operating costs as well as the demands they place on operator skills, a staggering number of these new microscopes has already been installed worldwide. Serious challenges, therefore, arise including the need to attract customers from a wide range of disciplines where complex structure problems may require the development of new imaging modes. The ability to image at large scattering angles may be useful in mitigating some of the many as-yet uncorrected delocalization mechanisms that then arise and are systematically identified here. Larger specimen volumes made possible by chromatic aberration correction will benefit the development of more relevant in situ observations, particularly in materials science and catalysis. With additional incorporation of phase shifting electrodes or other devices, these chromatic aberration correctors could also be important for efficient phase contrast imaging in easily damaged biological structures. For many of these formidable problems, earlier experience of the optical microscopy community may teach some lessons.

scholarly journals A versatile nanoreactor for complementary in situ X-ray and electron microscopy studies in catalysis and materials science

2019 ◽  
Vol 26 (5) ◽  
pp. 1769-1781 ◽  
Author(s):  
Yakub Fam ◽  
Thomas L. Sheppard ◽  
Johannes Becher ◽  
Dennis Scherhaufer ◽  
Heinz Lambach ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Functional Materials ◽  
Ambient Conditions ◽  
Zeolite Sample ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Wide Range ◽  
Modular Platform

Two in situ `nanoreactors' for high-resolution imaging of catalysts have been designed and applied at the hard X-ray nanoprobe endstation at beamline P06 of the PETRA III synchrotron radiation source. The reactors house samples supported on commercial MEMS chips, and were applied for complementary hard X-ray ptychography (23 nm spatial resolution) and transmission electron microscopy, with additional X-ray fluorescence measurements. The reactors allow pressures of 100 kPa and temperatures of up to 1573 K, offering a wide range of conditions relevant for catalysis. Ptychographic tomography was demonstrated at limited tilting angles of at least ±35° within the reactors and ±65° on the naked sample holders. Two case studies were selected to demonstrate the functionality of the reactors: (i) annealing of hierarchical nanoporous gold up to 923 K under inert He environment and (ii) acquisition of a ptychographic projection series at ±35° of a hierarchically structured macroporous zeolite sample under ambient conditions. The reactors are shown to be a flexible and modular platform for in situ studies in catalysis and materials science which may be adapted for a range of sample and experiment types, opening new characterization pathways in correlative multimodal in situ analysis of functional materials at work. The cells will presently be made available for all interested users of beamline P06 at PETRA III.

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