Thermal hysteresis induced by external pressure in a 3D Hofmann-type SCO-MOF

Dalton Transactions ◽

10.1039/d0dt03796f ◽

2021 ◽

Author(s):

Yue Li ◽

Qingrong Kong ◽

Ying Guo ◽

Zheng Tang

Keyword(s):

Thermal Hysteresis ◽

External Pressure ◽

Monodentate Ligand ◽

One Step

Two isostructural 3D Hofmann-type frameworks, [FeII(dbdpe)MII(CN)4]·4H2O (M = Pt for 1 and Pd for 2), were synthesized based on a bis-monodentate ligand dbdpe (1,2-dibromo-1,2-di(pyridin-4-yl)ethane). Both compounds underwent similar one-step incomplete...

Download Full-text

Paraffin/polyacrylonitrile hybrid nanofibers for thermal hysteresis enhancement of paraffin actuators

Journal of Industrial Textiles ◽

10.1177/1528083721988964 ◽

2021 ◽

pp. 152808372198896

Author(s):

Ahmet Kutlu ◽

Recep Eren ◽

Yakup Aykut

Keyword(s):

Melting Point ◽

Thermal Hysteresis ◽

Contrast Ratio ◽

Threshold Effect ◽

Scanning Calorimetry ◽

Cooling Systems ◽

Hybrid Nanofibers ◽

One Step ◽

Hybrid Nanofiber ◽

Opening And Closing

Fast and facile one-step preparation of paraffin/polyacrylonitrile hybrid nanofibers via single needle (uniaxial) electrospinning system was studied. As-spun paraffin/polyacrylonitrile nanofibers were used for thermal hysteresis enhancement of paraffin actuators. Solid paraffin with the melting point of 32, 58, 89 and 114°C were employed for the preparation of the paraffin/polyacrylonitrile nanofibers. Differential scanning calorimetry measurements revealed that the melting point of the paraffin in paraffin/polyacrylonitrile hybrid nanofiber was clearly detectable and the melting entalpy coming from the paraffin part gradually increased from 9.6 to 101.5 J/g with the increase in the melting points of the added same amount of paraffins in paraffin/polyacrylonitrile nanofibers. When both calorimetric and weight loss measurements were considered, the paraffin which has the melting point of 32°C was found to be suitable to produce hybrid nanofibers paraffin actuator. Therefore, this hybrid nanofiber was selected for the application in paraffin actuators for e-vehicle battery cooling systems where the battery temperature must be kept between 15 and 35°C. Paraffin compound of the paraffin actuators was prepared with a mixture of pure paraffin and paraffin/polyacrylonitrile nanofiber with the wt.% of 2.5, 5, 7.5 and 10. In the hysteresis measurements, the hysteresis value at 3 mm stroke was successfully enhanced as 1.7, 3.4, 11.9 and 15.3% sequentially for the samples produced with the above ratios. Beyond hysteresis enhancement, the phenomena of thermal percolation threshold effect and thermal conductivity contrast ratio effect in nano scale were emprically exposed on opening and closing behavior of the paraffin actuator.

Download Full-text

Combustion-synthesized functionally gradient refractory materials

Journal of Materials Research ◽

10.1557/jmr.1993.2026 ◽

1993 ◽

Vol 8 (8) ◽

pp. 2026-2034 ◽

Cited By ~ 20

Author(s):

Scott E. Niedzialek ◽

Gregory C. Stangle ◽

Yoshinari Kaieda

Keyword(s):

Temperature Control ◽

Reaction Temperature ◽

Applied Pressure ◽

External Pressure ◽

Powder Size ◽

Starting Mixture ◽

Functionally Gradient ◽

High Temperature Synthesis ◽

One Step ◽

Commercial Applications

Functionally Gradient Materials (FGM's) are soon to be used in a variety of important commercial applications; joining and thermal barrier coatings are two of the most widely studied. FGM's of the TiC/NiAl and the TiC/Ni3Al systems were fabricated using a one-step, self-propagating high-temperature synthesis (SHS) and densification method. It was observed that ignition of the starting mixture for these two systems was affected by the initial sample temperature and the external pressure that was applied to the sample during the ignition stage. Quality of the final product (e.g., porosity, grain size, cracking and microcracking, etc.) depends on a number of factors during this one-step operation. Reaction temperature control is important and is necessary to minimize residual porosity of the final product. Particle size of reactant powders, as well as applied pressure, also has an effect on the resulting microstructure. If careful reaction temperature control is achieved, along with optimum reactant powder size and applied pressure, an FGM of minimal porosity is obtained without residual macrocracks. Further, this method can easily be used to fabricate an FGM with a highly precise composition and material properties gradient. Finally, this process results in FGM's of similar quality when compared to those prepared by existing fabrication methods at only a fraction of the cost. Most importantly, it is expected that this process can be scaled up with relative ease.

Download Full-text

An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092670 ◽

1976 ◽

Vol 34 ◽

pp. 542-543

Author(s):

R.P. Goehner ◽

W.T. Hatfield ◽

Prakash Rao

Keyword(s):

Electron Diffraction ◽

Real Time ◽

Pattern Analysis ◽

Flow Diagram ◽

Hard Copy ◽

Time Analysis ◽

Real Time Analysis ◽

Transmission Electron ◽

One Step ◽

Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

Download Full-text

Spin-crossover in an iron(iii) complex showing a broad thermal hysteresis

Dalton Transactions ◽

10.1039/d0dt03610b ◽

2021 ◽

Author(s):

Cyril Rajnák ◽

Romana Mičová ◽

Ján Moncoľ ◽

Ľubor Dlháň ◽

Christoph Krüger ◽

...

Keyword(s):

Schiff Base ◽

Schiff Base Ligand ◽

Spin Crossover ◽

Thermal Hysteresis ◽

Mononuclear Complex ◽

Hysteresis Width ◽

Thermally Induced

A pentadentate Schiff-base ligand 3,5Cl-L2− and NCSe− form a iron(iii) mononuclear complex [Fe(3,5Cl-L)(NCSe)], which shows a thermally induced spin crossover with a broad hysteresis width of 24 K between 123 K (warming) and 99 K (cooling).

Download Full-text

Nutrient-regulated gene expression in eukaryotes

Biochemical Society Symposium ◽

10.1042/bss0730085 ◽

2006 ◽

Vol 73 ◽

pp. 85-96 ◽

Cited By ~ 8

Author(s):

Richard J. Reece ◽

Laila Beynon ◽

Stacey Holden ◽

Amanda D. Hughes ◽

Karine Rébora ◽

...

Keyword(s):

Gene Expression ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Transcriptional Control ◽

Direct Interaction ◽

Signalling Pathways ◽

A Cell ◽

One Step ◽

Higher Eukaryotes ◽

Regulated Gene Expression

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.

Download Full-text