scholarly journals Control of a thermosalient phase transition by solid solutions

2014 ◽  
Vol 70 (a1) ◽  
pp. C985-C985
Author(s):  
Elisa Nauha ◽  
Matteo Lusi ◽  
Pance Naumov
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
Energy Conversion ◽  
Solid Solutions ◽  
Thermal Energy ◽  
Molecular Crystal ◽  
Mechanical Performance ◽  
Mixed Crystals ◽  
Macro Scale ◽  
Scale Motion

Thermosalient crystals that exhibit macro-scale motion upon phase transition could be useful as actuators that are capable of converting thermal energy into motion or mechanical work in macroscopic devices.[1] The application capability of these miniature actuators for energy conversion depends on the temperature range and dynamics of transition. While the thermo-mechanical performance cannot be systematically varied with a pure molecular crystal, solid solutions could present a way to intentionally tune both the dynamics and the temperature of the transition in a continuous manner (Figure 1). To verify this hypothesis, Zn(2,2'-bpy)Br2,[2] was selected as a thermosalient material which could form solid solutions (or mixed complexes) with Zn(2,2'-bpy)Cl2. Only one form (isomorphous to one of the two Zn(2,2'-bpy)Br2forms) has been reported for the chloride.[3] The results indicate that indeed, the two complexes form solid solutions in varying ratios. The mixed crystals undergo the same phase transformation as the pure Zn(2,2'-bpy)Br2at a Cl/Br-ratio-dependent temperature. The temperature and dynamics of the thermosalient phenomenon correlates with the Cl/Br-ratio.

Notizen: Austausch von Nitrit- gegen Bromidanionen in Na3NO3 / Replacement of Nitrite by Bromide Anions in Na3NO3

1989 ◽  
Vol 44 (8) ◽  
pp. 996-998 ◽  
Author(s):  
M. Jansen ◽  
W. Müller
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Solid Solutions ◽  
Room Temperature ◽  
Mixed Crystals ◽  
Miscibility Gap ◽  
Temperature Range ◽  
Collective Interactions

Na3O(NO2) and Na3OBr are isostructural and form solid solutions with a miscibility gap χ = 0.28 to 0.62 as referred to Na3OBrx(NO2)1-x, at room temperature. Above 593 Κ formation of mixed crystals was observed for all compositions. In contrast to pure Na3O(NO2), the solid solutions do not undergo any phase transition in the investigated temperature range from 293 Κ to 130 K. These findings reveal that collective interactions between the dynamically disordered NO2--groups are involved in the phase transitions of Na3NO3.

scholarly journals Superelasticity of a photo-actuating chiral salicylideneamine crystal

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Takuya Taniguchi ◽  
Kazuki Ishizaki ◽  
Daisuke Takagi ◽  
Kazuki Nishimura ◽  
Hiroki Shigemune ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
External Force ◽  
Molecular Crystal ◽  
Light Irradiation ◽  
Elastic Response ◽  
Layer Model ◽  
Induced Stress ◽  
External Stimuli

AbstractSuperelasticity is a type of elastic response to an applied external force, caused by a phase transformation. Actuation of materials is also an elastic response to external stimuli such as light and heat. Although both superelasticity and actuation are deformations resulting from stimulus-induced stress, there is a phenomenological difference between the two with respect to whether force is an input or an output. Here, we report that a molecular crystal manifests superelasticity during photo-actuation under light irradiation. The crystal exhibits stepwise twisted actuation due to two effects, photoisomerization and photo-triggered phase transition, and the actuation behavior is simulated based on a dynamic multi-layer model. The simulation, in turn, reveals how the photoisomerization and phase transition progress in the crystal, indicating superelasticity induced by modest stress due to the formation of photoproducts. This work provides not only a successful simulation of stepwise twisted actuation, but also to the best of our knowledge the first indication of superelasticity induced by light.

A further study of analcime solid solutions in the system NaAlSi3O8-NaAISiO4-H20, with particular note of an analcime phase transformation

1980 ◽  
Vol 43 (332) ◽  
pp. 1035-1045 ◽  
Author(s):  
Ki-Tae Kim ◽  
B. J. Burley
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Phase Transformation ◽  
Solid Solutions ◽  
Total Pressure ◽  
Room Temperature ◽  
Water Pressure ◽  
Stability Field ◽  
Cell Parameters ◽  
The Stability

SummaryThe stability field of analcime solid solutions in the system NaAlSi3O8-NaAlSiO4-H2O has been previously determined by Kim and Burley (1971a). These experiments are re-examined with a view to determining the variations of the room-temperature cell parameters of analcime as a function of temperature of synthesis and composition. It is shown from this evidence that most of the analcime solid solutions in these experiments are equilibrium compositions. The increase in the cell dimension of quenched analcime solid solution is found to be 5 × 10−5 Å/°C. It is suggested that birefringence in analcime is induced by low water-pressure relative to total pressure. A phase transition appears to be observed in quenched analcimes of this study and is thought to be the same as that in the Golden analcime reported by Yoder and Weir (1960).

scholarly journals Ocean Thermal Energy Conversion—Flexible Enabling Technology for Variable Renewable Energy Integration in the Caribbean

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2192
Author(s):  
Robert J. Brecha ◽  
Katherine Schoenenberger ◽  
Masaō Ashtine ◽  
Randy Koon Koon
Keyword(s):  
Climate Change ◽  
Renewable Energy ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Small Island ◽  
Gis Mapping ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Hourly Data ◽  
Ocean Thermal Energy

Many Caribbean island nations have historically been heavily dependent on imported fossil fuels for both power and transportation, while at the same time being at an enhanced risk from the impacts of climate change, although their emissions represent a very tiny fraction of the global total responsible for climate change. Small island developing states (SIDSs) are among the leaders in advocating for the ambitious 1.5 °C Paris Agreement target and the transition to 100% sustainable, renewable energy systems. In this work, three central results are presented. First, through GIS mapping of all Caribbean islands, the potential for near-coastal deep-water as a resource for ocean thermal energy conversion (OTEC) is shown, and these results are coupled with an estimate of the countries for which OTEC would be most advantageous due to a lack of other dispatchable renewable power options. Secondly, hourly data have been utilized to explicitly show the trade-offs between battery storage needs and dispatchable renewable sources such as OTEC in 100% renewable electricity systems, both in technological and economic terms. Finally, the utility of near-shore, open-cycle OTEC with accompanying desalination is shown to enable a higher penetration of renewable energy and lead to lower system levelized costs than those of a conventional fossil fuel system.

scholarly journals Estimation of Ocean Thermal Energy Conversion Resources in the East of Malaysia

2020 ◽  
Vol 9 (1) ◽  
pp. 22
Author(s):  
Sathiabama T. T. Thirugnana ◽  
Abu Bakar Jaafar ◽  
Takeshi Yasunaga ◽  
Tsutomu Nakaoka ◽  
Yasuyuki Ikegami ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Biomass Energy ◽  
Relative Depth ◽  
Solar Pv ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Oceanographic Data ◽  
Ocean Thermal Energy

The Malaysian Government has set a target of achieving 20% penetration of Renewable Energy (RE) in the energy mix spectrum by 2025. In order to get closer to the target, Ocean Thermal Energy Conversion (OTEC) aligned with solar PV, biogas and biomass energy sources must be evaluated and comprehended. Hybrid OTEC systems consisting of energy and water production are currently under research and validation. Therefore, for the construction of a commercial OTEC plant, 1 MW or 2.5 MW, the choice of a strategic location or potential site is vital. In this paper, oceanographic data such as seawater temperature, depth, salinity and dissolved oxygen obtained from the Japan Oceanographic Data Center (JODC) for Semporna, Tawau, Kudat, Pulau Layang-Layang and Pulau Kalumpang in Sabah, Malaysia, are reported. The RE available from the Exclusive Economic Zone (EEZ) on the coast of Sabah was estimated based on the JODC data obtained. There were no remarkable differences in temperatures between the five sites, which were reported as approximately 27 °C at the surface and 7 °C at depths below 600 m. The surface salinities below 100 m at those sites were slightly lower than the deeper waters, where the salinity increased up to approximately 34.5 PSU. Dissolved oxygen data from the Pulau Kalumpang site showed a slight increment to approximately 4.7 mL/L at depth intervals below 50 m, before declining steadily to approximately 1.7 mL/L along with the depth. The temperature-salinity profiles of the Malaysian sites were congruent with those of Palau, Kumejima and Okinawa, but not with that of Fiji, where the salinity profile showed a distinct variation at the relative depth (below 200 m). Estimates of RE using two different methods were used to prove the potential of OTEC in Malaysia.

scholarly journals Pressure-Induced Structural Phase Transition and Metallization in Ga2Se3 up to 40.2 GPa under Non-Hydrostatic and Hydrostatic Environments

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 746
Author(s):  
Meiling Hong ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Xinyu Zhang
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
High Pressure ◽  
Phase Transformation ◽  
Transport Properties ◽  
Electrical Transport ◽  
Structural Phase ◽  
Structure Evolution ◽  
Systematic Research ◽  
Electrical Transport Properties

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.

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