| 1. |
- Fenstermacher, M.E., et al.
(författare)
-
DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
-
Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
|
|
| 2. |
- Hu, Q., et al.
(författare)
-
Effect of Mo on high-temperature strength of refractory complex concentrated alloys: A perspective of electronegativity difference
- 2022
-
Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 906
-
Tidskriftsartikel (refereegranskat)abstract
- Refractory complex concentrated alloys, RCCAs, show great potential for ultrahigh-temperature applications. High-temperature strength is one of the key requirements for RCCAs to qualify for that purpose. Some RCCAs already show superior high-temperature strength than that of commercial Ni-based superalloys, but many other RCCAs do not. It is thus important to identify the key factors that control the high-temperature strength of RCCAs. In this work, based on a statistic analysis of the yield strength at 1000 °C (σy1000) for 55 reported RCCAs, interestingly, it is revealed that Mo-containing RCCAs have in general a higher σy1000 than those RCCAs not containing Mo. The effect of Mo is attributed to its larger electronegativity and hence the larger electronegativity difference to other alloying elements, rather than to its higher melting point. The previously established proposal that a large electronegativity difference favoring the charge transfer and creating an atomic-level pressure that contributes to the strengthening of RCCAs at room temperature, seems effective even at a high temperature of 1000 °C. In addition, the large electronegativity difference also favors the room-temperature strength of single-bcc-phase RCCAs. The findings from this work, further verified experimentally in six new RCCAs, shed light on new research directions to develop RCCAs with decent strength at both high temperatures and room temperature, using a simple descriptor on the electronegativity difference.
|
|
| 3. |
- Wang, Z. R., et al.
(författare)
-
Effect of Si addition on Curie temperature and thermal expansion coefficient of (Fe 71.2 B 24 Y 4.8 ) 96 Nb 4 Invar bulk metallic glasses
- 2024
-
Ingår i: Journal of Applied Physics. - 0021-8979 .- 1089-7550. ; 136:4
-
Tidskriftsartikel (refereegranskat)abstract
- The ultra-low thermal expansion coefficient α makes the Fe-Ni Invar alloys useful in various applications. Their low strength and low Curie temperature Tc are, however, limiting factors. Interestingly, some Fe-based bulk metallic glasses (BMGs), with inherent high strength, exhibit the clear Invar effect. In particular, the (Fe71.2B24Y4.8)96Nb4 BMG has the lowest α among Fe-based BMGs, but it unfortunately also has the lowest Tc. In this work, silicon was added into this alloy with the aim to elevate Tc while maintaining a low α. It was found that when silicon partially substituted boron, Tc did not increase significantly but α did, which is not ideal. On the other hand, when silicon partially substituted yttrium and niobium and especially niobium, Tc increased significantly while α did not, which is close to the ideal scenario. When 3% of niobium was substituted by silicon, Tc reached the maximum value of 296 °C while α remained a low value of 7.4 × 10−6/°C. Comparing to the Fe-Ni Invar alloy, although this BMG has an inferior α, it has much higher Tc (+115 °C) and strength (∼9 times), presenting a potential for application as a new Invar material with moderate (low) thermal expansion, high operating temperature, and high strength.
|
|
| 4. |
- Sun, Q., et al.
(författare)
-
A Comprehensive Review of Smart Energy Meters in Intelligent Energy Networks
- 2016
-
Ingår i: IEEE Internet of Things Journal. - 2327-4662. ; 3:4, s. 464-479
-
Tidskriftsartikel (refereegranskat)abstract
- The significant increase in energy consumption and the rapid development of renewable energy, such as solar power and wind power, have brought huge challenges to energy security and the environment, which, in the meantime, stimulate the development of energy networks toward a more intelligent direction. Smart meters are the most fundamental components in the intelligent energy networks (IENs). In addition to measuring energy flows, smart energy meters can exchange the information on energy consumption and the status of energy networks between utility companies and consumers. Furthermore, smart energy meters can also be used to monitor and control home appliances and other devices according to the individual consumer's instruction. This paper systematically reviews the development and deployment of smart energy meters, including smart electricity meters, smart heat meters, and smart gas meters. By examining various functions and applications of smart energy meters, as well as associated benefits and costs, this paper provides insights and guidelines regarding the future development of smart meters.
|
|
| 5. |
- Gačnik, Darja, et al.
(författare)
-
Structure and superconductivity of tin-containing hftizrsnm (M = cu, fe, nb, ni) medium-entropy and high-entropy alloys
- 2021
-
Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 14:14
-
Tidskriftsartikel (refereegranskat)abstract
- In an attempt to incorporate tin (Sn) into high-entropy alloys composed of refractory metals Hf, Nb, Ti and Zr with the addition of 3d transition metals Cu, Fe, and Ni, we synthesized a series of alloys in the system HfTiZrSnM (M = Cu, Fe, Nb, Ni). The alloys were characterized crystallographically, microstructurally, and compositionally, and their physical properties were determined, with the emphasis on superconductivity. All Sn-containing alloys are multi-phase mixtures of intermetallic compounds (in most cases four). A common feature of the alloys is a microstructure of large crystalline grains of a hexagonal (Hf, Ti, Zr)5Sn3 partially ordered phase embedded in a matrix that also contains many small inclusions. In the HfTiZrSnCu alloy, some Cu is also incorporated into the grains. Based on the electrical resistivity, specific heat, and magnetization measurements, a superconducting (SC) state was observed in the HfTiZr, HfTiZrSn, HfTiZrSnNi, and HfTiZrSnNb alloys. The HfTiZrSnFe alloy shows a partial SC transition, whereas the HfTiZrSnCu alloy is non-superconducting. All SC alloys are type II superconductors and belong to the Anderson class of “dirty” superconductors.
|
|
| 6. |
- Hu, Q., et al.
(författare)
-
Anomalous thermal expansion in the deep super-cooled liquid region of a ZrCuAlAg bulk metallic glass
- 2018
-
Ingår i: Materials Research Letters. - : Informa UK Limited. - 2166-3831. ; 6:2, s. 121-129
-
Tidskriftsartikel (refereegranskat)abstract
- Bulk metallic glasses (BMGs), like other glasses, soften in the super-cooled liquid region (SCLR). Here in this work, surprisingly, a large expansion is reported occurring in the deep SCLR of a Zr 47 Cu 37 Al 8 Ag 8 BMG. Nano-crystals (NCs) are found precipitated during the anomalous expansion of Zr 47 Cu 37 Al 8 Ag 8 , but also in the SCLR of Zr 43 Cu 41 Al 8 Ag 8 that exhibits a conventional softening. It is found that there is a steep composition and density change at the NCs/amorphous matrix transition region in the former alloy, and this transition region exerts a thermal stress of about 0.15 MPa to the surrounding super-cooled liquid (SCL) and drives the soft SCL to expand severely. (Figure presented) IMPACT STATEMENT An anomalous expansion, and particularly a large expansion instead of softening, is reported occurring in the deep SCLR of a Zr-based bulk metallic glass for the first time.
|
|
| 7. |
- Ouyang, D. L., et al.
(författare)
-
Influence of casting temperature on the castability and glass-forming ability of Zr-based bulk metallic glasses
- 2023
-
Ingår i: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093. ; 603
-
Tidskriftsartikel (refereegranskat)abstract
- Both castability and glass-forming ability (GFA) are crucial for die-casting of Zr-based bulk metallic glass (BMG) components. In this work, a simple method is used to quantify the castability required for casting two SIM card slots with different designs, and to quantify the castability at different casting temperatures. It is found that the Zr55Cu30Ni5Al10 (Zr55) BMG has a wider optimal casting temperature region (in which glassy rods with a diameter of at least 5 mm can be formed) than that of Zr52.5Cu25Ni9.5Al7Ti6 (Zr52.5), which is consistent of the better GFA of the Zr55. In the optimal casting temperature region, however, the castability of Zr52.5 is significantly better than that of Zr55, because Zr52.5 has a lower melting point, a poorer wettability to the copper mold, and a higher optimal casting temperature. These results are helpful to guide the production of Zr-based BMG components.
|
|
| 8. |
- Guo, Q., et al.
(författare)
-
A study on protecting of the far side occupants based on road traffic accident reconstruction
- 2012
-
Ingår i: 2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012. Guilin, Guangxi, 31 July - 2 August 2012. - 9780769547725 ; , s. 140-143
-
Konferensbidrag (refereegranskat)abstract
- A study on injuries of far side passenger in vehicle side impact was carried out by using a real road accident. Firstly, the trace of the accident car was reproduced using PC-Crash code. The impact velocity of the passenger car calculated from PC-Crash was used as the input data for MADYMO modeling of occupant kinematics. Then the dynamic responses of the occupants were analyzed using the calculated injury parameters of the driver. Furthermore, LS-DYNA code was used to simulate the impact between the head of the driver and the left shoulder of the occupant. In the end, a MADYMO model with an airbag between driver and occupant was developed, and the protective efficiency of the airbag was showed by comparing the models with and without airbag.
|
|
| 9. |
- Guo, S., et al.
(författare)
-
Mobilized thermal energy storage : Materials, containers and economic evaluation
- 2018
-
Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 177, s. 315-329
-
Tidskriftsartikel (refereegranskat)abstract
- The transportation of thermal energy is essential for users who are located far away from heat sources. The networks connecting them achieve the goal in efficient heat delivery and reasonable cost, especially for the users with large heat demands. However, it is difficult to satisfy the heat supply of the detached or emergent users with the existing pipelines. Therefore, a promising alternative, called mobilized thermal energy storage (M-TES), was proposed to deliver the heat flexibly without the restriction of networks. In this paper, a review of studies on M-TES is conducted in terms of materials, containers and economic evaluation. The potential candidates of materials, such as sugar alcohols, hydrated salts, alkalies and zeolite are reviewed and compared based on their thermophysical properties, price, advantages and disadvantages. Various containers, including the shell-and-tube, encapsulated, direct-contact, detachable and sorptive types, are discussed from the aspects of configuration, performance and utilization. Furthermore, the studies on the economic evaluation of M-TES systems are summarized and discussed based on the analysis of the economic indicators, including initial cost, operating cost, revenue, subsidy and energy cost. Finally, the challenges and future perspectives for developing M-TES are presented.
|
|
| 10. |
- Sheikh, Saad Ahmed, 1987, et al.
(författare)
-
Alloy design for intrinsically ductile refractory high-entropy alloys
- 2016
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 120:16, s. Art no 164902-
-
Tidskriftsartikel (refereegranskat)abstract
- Refractory high-entropy alloys (RHEAs), comprising group IV (Ti, Zr, Hf), V (V, Nb, Ta), and VI (Cr, Mo, W) refractory elements, can be potentially new generation high-temperature materials. However, most existing RHEAs lack room-temperature ductility, similar to conventional refractory metals and alloys. Here, we propose an alloy design strategy to intrinsically ductilize RHEAs based on the electron theory and more specifically to decrease the number of valence electrons through controlled alloying. A new ductile RHEA, Hf0.5 Nb 0.5 Ta 0.5Ti1.5Zr, was developed as a proof of concept, with a fracture stress of close to 1 GPa and an elongation of near 20%. The findings here will shed light on the development of ductile RHEAs for ultrahigh-temperature applications in aerospace and power-generation industries.
|
|
