liquid states
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2021 ◽  
Vol 5 (3) ◽  
Author(s):  
O.V. Kholiavik ◽  
Alexey Nogovitsyn ◽  
Alexey Kravchuk ◽  
Alexey Samoylenko ◽  
Ruslan Boris

Problems. In the process of obtaining a strip in a casting and rolling device, the question arises of combining the process of hot rolling of the solidified material and the process of crystallization of the liquid melt. This makes it possible to implement an efficient technology for producing thin-sheet products. Purpose of the study. Determination of rational parameters for performing mathematical modeling of material behavior during roll casting requires clearly defined recommendations. The material for the rolling process is steel. The starting material was used in solid, solid-liquid and liquid states. Implementation technique. The analysis of the properties of steel was carried out on the basis of the results of experiments obtained at the Physico-Technological Institute of Metals and Alloys of the National Academy of Sciences of Ukraine. To analyze the rheological properties of steel, the dependences of the yield stress for alloyed and carbon steels were used in a certain temperature range. The selected temperature range includes solidus and solid-liquid state of steel, located above 0.8 melting point. Research results. Based on the research results, the analysis of the rheological properties of steel in solid, solid-liquid and liquid states during continuous casting-rolling on rolls was carried out. The use of the obtained dependencies makes it possible to perform mathematical modeling of the deformation and hydrodynamics of the material during continuous casting-rolling of steel strips using roll casting-rolling devices. Conclusions. The constructed dependences, together with studies of the viscosity of steel in the liquid state and the resistance of steel to deformation in the solid state, most fully describe the rheological properties of steels during casting-deformation processes. The obtained dependences will make it possible to implement an ultra-efficient technology for producing thin-sheet rolled products.


2021 ◽  
Vol 13 (4) ◽  
pp. 66
Author(s):  
Krzysztof Petelczyc

Receiving the Nobel Prize in 1971 for the invention and development of the holographic method, Dennis Gabor mentioned Mieczysław Wolfke as the person who proposed this method as early as 1920 (which he did not know, independently making the same discovery). This article describes the history of Wolfke's pioneering work and tries to recreate the thought process that led to it - starting with the task of supplementing and verifying the diffraction grating theory proposed by Ernst Abbe, which he carried out as part of his doctorate at the University of Wrocław and habilitation at the University of Zurich and the Swiss Federal Institute of Technology in Zurich.. Full Text: PDF ReferencesW. Łaniecki, Kwartalnik Historii Nauki i Techniki, 21, 545-553 (1976). DirectLink W. Keesom, "Solidification of Helium", Nature 118, 81 (1926). CrossRef W. Keesom, M. Wolfke, "Two liquid states of helium", Konink. Akad. Wetensch. Amsterdam, Proc, 31(190b), 90-94 (1928).W. Keesom, Helium (Elsevier, Amsterdam 1942).E. Abbe, Die Lehre von der Bildentstehung im Mikroskop (F. Vieweg, Braunschweig 1910). CrossRef R. Torge, Postępy Fizyki, 53, 201-210 (2002). CrossRef A.Kiejna, Kwartalnik Historii Nauki i Techniki, 48, 7 (2003). DirectLink M. Wolfke, "Über die Abbildung eines Gitters bei künstlicher Begrenzung", Ann Phys. 339, 277 (1911). CrossRef M. Wolfke, Prace matematyczno-fizyczne, 22, 135 (1911). DirectLink M. Wolfke, "Über die Abbildung eines Gitters bei asymmetrischer Abblendung", Ann Phys. 342, 96 (1912). CrossRef M. Wolfke, "Über die Abbildung eines durchlässigen Gitters", Ann Phys. 342, 797 (1912). CrossRef M. Wolfke, "Zur Abbildung eines durchlässigen Gitters", Ann Phys. 343, 385 (1912). CrossRef K. Petelczyc, E. Kędzierska, Mieczysław Wolfke. Gdyby mi dali choć pół miliona… (OWPW, Warszawa 2018). DirectLink L.A. Aslanov, G.V. Fetisov, J.A.K. Howard, "Crystallographic Instrumentation", Oxford (1998). CrossRef M. Wolfke, Wiadomości matematyczne 17, 1 (1913). DirectLink M. Wolfke, "Allgemeine Abbildungstheorie selbstleuchtender und nicht selbstleuchtender Objekte", Ann Phys. 344, 569 (1912). CrossRef M. Wolfke, "Über die Abbildung eines Gitters außerhalb der Einstellebene", Ann Phys. 345, 194 (1913). CrossRef M. Wolfke, Verhandlungen der DPG, 15, 1123 (1913).M. Wolfke, Verhandlungen der DPG, 15, 1215 (1913).M. Wolfke, Verhandlungen der DPG, 16, 4 (1914).M. Wolfke, "Fragen zur Pathologie des menschlichen Oedems", Physikalische Zeitschrift, 22, 375 (1921). CrossRef Akta osobowe - Wolfke Mieczysław, Archiwum Akt Nowych sygn. 2/14/0/6/6638, WarszawaM. Wolfke, Physikalische Zeitschrift, 21, 495 (1920). DirectLink S. Lundqvist, Nobel Lectures, Physics 1971-1980 (World Scientific Publishing Co. Singapore 1992) CrossRef


Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qianying Lu ◽  
Yunlei Zhou ◽  
Xiangfei Yin ◽  
Shitai Cao ◽  
Xiaoliang Wang ◽  
...  

In contrast to ionically conductive liquids and gels, a new type of yield-stress fluid featuring reversible transitions between solid and liquid states is introduced in this study as a printable, ultrastretchable, and transparent conductor. The fluid is formulated by dispersing silica nanoparticles into the concentrated aqueous electrolyte. The as-printed features show solid-state appearances to allow facile encapsulation with elastomers. The transition into liquid-like behavior upon tensile deformations is the enabler for ultrahigh stretchability up to the fracture strain of the elastomer. Successful integrations of yield-stress fluid electrodes in highly stretchable strain sensors and light-emitting devices illustrate the practical suitability. The yield-stress fluid represents an attractive building block for stretchable electronic devices and systems in terms of giant deformability, high ionic conductivity, excellent optical transmittance, and compatibility with various elastomers.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1968
Author(s):  
Abdulsalam Muhrat ◽  
Joaquim Barbosa

Brazing joints of Ti/Ti under ultrasonic vibration (USV) and compression load were investigated using optimized and modified filler alloys of Al-Si-Cu-(Ni)-(Sr) group prepared in the lab. Preliminary trails at semisolid to liquid states were conducted using the ready Al-Si-Cu-(Mg) alloy as a filler, then the brazing cycle was redesigned and enhanced according to the microstructural observations of the produced joints. USV assisted brazing at semisolid state of low solid fraction was able to produce joints with round silicon morphology and granular , while at high solid fraction, USV was only able to affect the silicon and intermetallic particles. Applying a compression load after ultrasonic vibration, at a designed solid fraction, was proved to be a successful technique for improving the quality of the joints by reducing the porosity, enhancing the soundness of the joint, and the diffusion at the interface. Based on alloy composition and the improved brazing cycle, joints of thin intermetallic layer and high shear strength (of 93 MPa average value) were achieved. The microstructures and the mechanical behavior were discussed based on the filler compositions and brazing parameters.


2021 ◽  
Vol 28 ◽  
pp. 101184
Author(s):  
Tuan Phan-Xuan ◽  
Ekaterina Bogdanova ◽  
Jens Sommertune ◽  
Anna Millqvist Fureby ◽  
Jonas Fransson ◽  
...  

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jeffrey C. Hansen ◽  
Kazuhiro Maeshima ◽  
Michael J. Hendzel

AbstractThe review begins with a concise description of the principles of phase separation. This is followed by a comprehensive section on phase separation of chromatin, in which we recount the 60 years history of chromatin aggregation studies, discuss the evidence that chromatin aggregation intrinsically is a physiologically relevant liquid–solid phase separation (LSPS) process driven by chromatin self-interaction, and highlight the recent findings that under specific solution conditions chromatin can undergo liquid–liquid phase separation (LLPS) rather than LSPS. In the next section of the review, we discuss how certain chromatin-associated proteins undergo LLPS in vitro and in vivo. Some chromatin-binding proteins undergo LLPS in purified form in near-physiological ionic strength buffers while others will do so only in the presence of DNA, nucleosomes, or chromatin. The final section of the review evaluates the solid and liquid states of chromatin in the nucleus. While chromatin behaves as an immobile solid on the mesoscale, nucleosomes are mobile on the nanoscale. We discuss how this dual nature of chromatin, which fits well the concept of viscoelasticity, contributes to genome structure, emphasizing the dominant role of chromatin self-interaction.


Author(s):  
Shanmuga Sundaram Anandan ◽  
Jagannathan Sundarababu ◽  
Rajesh Ravi ◽  
Kanchana Venkatesan

The low thermal conductivity of Phase Change Materials (PCM) reduces its performance and remains a challenging issue. In the present study, modified nano copper oxide powder (CuO) with various weight percentages is dispersed into paraffin wax to form Nano-PCM composites (NPCM). Transmission Electron Microscopy analysis showed the uniform dispersion of modified CuO and spherical in structure. Diffraction Scanning Calorimeter analysis (DSC) showed a trivial difference in the melting point of PCM and NPCM. The peak melting temperature of PCM was 18.56°C and for NPCM with 1% concentration was 17.14°C. The thermal conductivity of NPCM in solid and liquid states was high when compared to that of pure PCM. The thermal conductivity of NPCM with a 1% concentration is enhanced by 52% in a solid state and 20% in a liquid state. Solidification/Melting experiments conducted at different bath temperatures such as 15°C, 17°C, and 19°C for PCM and NPCM revealed that the solidification period and melting period reduced with an increase in concentrations of modified Nano CuO due to augmented heat transfer rates. The solidification time for NPCM with 1% concentration is reduced by 18.33% for discharging temperature 25°C, and melting time are reduced by 16.6% for charging temperature.


2021 ◽  
Vol 9 ◽  
Author(s):  
Paul C. M. Fossati ◽  
Alain Chartier ◽  
Alexandre Boulle

Some AX2 binary compounds with the fluorite structure (space group Fm3̄m) are well-known examples of materials exhibiting transitions to ionic superconducting phases at high temperatures below their melting points. Such superionic states have been described as either highly defective crystals or part-crystal, part-liquid states where the A ions retain their crystalline order whilst the X ions undergo partial melting. However, no detailed description of the structure of these phases exists. We present here the results of our investigation of the structural changes that occur during these transitions and the structural characteristics of the resulting superionic materials. This work is based on atomic-scale molecular dynamics modelling methods as well as computational diffraction techniques. We employed a set of empirical potentials representing several compounds with the fluorite structure to investigate any potential-dependent effect. We show the importance of small-scale structure changes, with some local environments showing a hexagonal symmetry similar to what is seen in the scrutinyite structure that has been documented for example in UO2.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alessio Chiocchetta ◽  
Dominik Kiese ◽  
Carl Philipp Zelle ◽  
Francesco Piazza ◽  
Sebastian Diehl

AbstractQuantum spin liquids provide paradigmatic examples of highly entangled quantum states of matter. Frustration is the key mechanism to favor spin liquids over more conventional magnetically ordered states. Here we propose to engineer frustration by exploiting the coupling of quantum magnets to the quantized light of an optical cavity. The interplay between the quantum fluctuations of the electro-magnetic field and the strongly correlated electrons results in a tunable long-range interaction between localized spins. This cavity-induced frustration robustly stabilizes spin liquid states, which occupy an extensive region in the phase diagram spanned by the range and strength of the tailored interaction. This occurs even in originally unfrustrated systems, as we showcase for the Heisenberg model on the square lattice.


Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5899
Author(s):  
Carmelo Corsaro ◽  
Enza Fazio

Liquid’s behaviour, when close to critical points, is of extreme importance both for fundamental research and industrial applications. A detailed knowledge of the structural–dynamical correlations in their proximity is still today a target to reach. Liquid water anomalies are ascribed to the presence of a second liquid–liquid critical point, which seems to be located in the very deep supercooled regime, even below 200 K and at pressure around 2 kbar. In this work, the thermal behaviour of the self-diffusion coefficient for liquid water is analyzed, in terms of a two-states model, for the first time in a very wide thermal region (126 K < T < 623 K), including those of the two critical points. Further, the corresponding configurational entropy and isobaric-specific heat have been evaluated within the same interval. The two liquid states correspond to high and low-density water local structures that play a primary role on water dynamical behavior over 500 K.


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