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Twisted : a cookbook : bold, unserious, delicious food for every occasion
Twisted's official cookbook, featuring 100+ never-before-seen, 100% delicious, easy-to-cook recipes that embody the Twisted ethos: unserious food tastes seriously good!
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Internal Flow in an Enhanced Tube Having Square-cut Twisted Tape Insert
In this study, a numerical simulation has been conducted in order to evaluate the thermal hydraulic performance of a turbulent single-phase flow inside an enhanced tube equipped with a square-cut twisted tape (STT) insert. The classical twisted tape (CTT) insert was also investigated for comparison. The k-ε renormalized group turbulence model has been utilized as the turbulent model. Various twist ratios (y/W) of 2.7, 4.5, and 6.5 were investigated for the Reynolds number range of 8000–18,000, with water as the working fluid. The numerical results indicated that, in comparison with the plain tube (PT), the tube equipped with the STT with the twist ratios of 2.7, 4.5, and 6.5 led to an increase in the values of the Nusselt number and friction factor in the inner tube by 45.4–80.7% and 2.0–3.3 times, respectively; in addition, the highest thermal performance of 1.23 has been obtained. The results further indicated that the tube equipped with the CTT of the same twist ratios improved the Nusselt number and friction factor in the inner tube by 40.3–74.4% and 1.7–3.0 times, respectively, in comparison with the PT; further, the maximum thermal performance of 1.18 was achieved.
Journal Article
Electrostatic effects, band distortions, and superconductivity in twisted graphene bilayers
Bilayer graphene twisted by a small angle shows a significant charge modulation away from neutrality, as the charge in the narrow bands near the Dirac point is mostly localized in a fraction of the Moiré unit cell. The resulting electrostatic potential leads to a filling-dependent change in the low-energy bands, of a magnitude comparable to or larger than the bandwidth. These modifications can be expressed in terms of new electron–electron interactions, which, when expressed in a local basis, describe electron-assisted hopping terms. These interactions favor superconductivity at certain fillings.
Journal Article
Tunable moiré bands and strong correlations in small-twist-angle bilayer graphene
According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moiré patterns produced by small misalignments between its individual layer honeycomb lattices. We have realized bilayer graphene moiré crystals with accurately controlled twist angles smaller than 1° and studied their properties using scanning probe microscopy and electron transport. We observe conductivity minima at charge neutrality, satellite gaps that appear at anomalous carrier densities for twist angles smaller than 1°, and tunneling densities-of-states that are strongly dependent on carrier density. These features are robust up to large transverse electric fields. In perpendicular magnetic fields, we observe the emergence of a Hofstadter butterfly in the energy spectrum, with fourfold degenerate Landau levels, and broken symmetry quantum Hall states at filling factors ±1, 2, 3. These observations demonstrate that at small twist angles, the electronic properties of bilayer graphene moiré crystals are strongly altered by electron–electron interactions.
Journal Article
The osa-miR164 target OsCUC1 functions redundantly with OsCUC3 in controlling rice meristem/organ boundary specification
• The specification of the meristem/organ boundary is critical for plant development. Here, we investigate two previously uncharacterized NAC transcription factors: the first, OsCUC1, which is negatively regulated by osa-miR164c, dimerizes with the second, OsCUC3, and functions partially redundantly in meristem/organ boundary specification in rice (Oryza sativa).
• We produced knockout lines for rice OsCUC1 (the homolog of Arabidopsis CUC1 and CUC2) and OsCUC3 (the homolog of Arabidopsis CUC3), as well as an overexpression line for osa-miR164c, to study the molecular mechanism of boundary specification in rice.
• A single mutation in either OsCUC1 or OsCUC3 leads to defects in the establishment of the meristem/organ boundary, resulting in reduced stamen numbers and the fusion of leaves and filaments, and the defects are greatly enhanced in the double mutant. Transgenic plants overexpressing osa-miR164c showed a phenotype similar to that of the OsCUC1 knockout line. In addition, knockout of OsCUC1 leads to multiple defects, including dwarf plant architecture, male sterility and twisted-rolling leaves. Further study indicated that OsCUC1 physically interacts with leaf-rolling related protein CURLED LEAF AND DWARF 1 (CLD1) and stabilizes it in the nucleus to control leaf morphology.
• This work demonstrated that the interplay of osa-miR164c, OsCUC1 and OsCUC3 controls boundary specification in rice.
Journal Article
Noncollinear phases in moiré magnets
We introduce a general framework to study moiré structures of two-dimensional Van der Waals magnets using continuum field theory. The formalism eliminates quasiperiodicity and allows a full understanding of magnetic structures and their excitations. In particular, we analyze in detail twisted bilayers of Néel antiferromagnets on the honeycomb lattice. A rich phase diagram with noncollinear twisted phases is obtained, and spin waves are further calculated. Direct extensions to zigzag antiferromagnets and ferromagnets are also presented. We anticipate the results and formalism demonstrated to lead to a broad range of applications to both fundamental research and experiments.
Journal Article
Coulomb interaction, phonons, and superconductivity in twisted bilayer graphene
The polarizability of twisted bilayer graphene, due to the combined effect of electron–hole pairs, plasmons, and acoustic phonons, is analyzed. The screened Coulomb interaction allows for the formation of Cooper pairs and superconductivity in a significant range of twist angles and fillings. The tendency toward superconductivity is enhanced by the coupling between longitudinal phonons and electron–hole pairs. Scattering processes involving large momentum transfers, Umklapp processes, play a crucial role in the formation of Cooper pairs. The magnitude of the superconducting gap changes among the different pockets of the Fermi surface.
Journal Article
Evidence for unconventional superconductivity in twisted bilayer graphene
The emergence of superconductivity and correlated insulators in magic-angle twisted bilayer graphene (MATBG) has raised the intriguing possibility that its pairing mechanism is distinct from that of conventional superconductors
1
–
4
, as described by the Bardeen–Cooper–Schrieffer (BCS) theory. However, recent studies have shown that superconductivity persists even when Coulomb interactions are partially screened
5
,
6
. This suggests that pairing in MATBG might be conventional in nature and a consequence of the large density of states of its flat bands. Here we combine tunnelling and Andreev reflection spectroscopy with a scanning tunnelling microscope to observe several key experimental signatures of unconventional superconductivity in MATBG. We show that the tunnelling spectra below the transition temperature
T
c
are inconsistent with those of a conventional
s
-wave superconductor, but rather resemble those of a nodal superconductor with an anisotropic pairing mechanism. We observe a large discrepancy between the tunnelling gap
Δ
T
, which far exceeds the mean-field BCS ratio (with 2
Δ
T
/
k
B
T
c
~ 25), and the gap
Δ
AR
extracted from Andreev reflection spectroscopy (2
Δ
AR
/
k
B
T
c
~ 6). The tunnelling gap persists even when superconductivity is suppressed, indicating its emergence from a pseudogap phase. Moreover, the pseudogap and superconductivity are both absent when MATBG is aligned with hexagonal boron nitride. These findings and other observations reported here provide a preponderance of evidence for a non-BCS mechanism for superconductivity in MATBG.
A study combining tunnelling and Andreev reflection spectroscopy with a scanning tunnelling microscope provides evidence for unconventional superconductivity in magic-angle twisted bilayer graphene.
Journal Article
Inner and Outer Twisted Derivations of Cyclic Group Rings
In this article, we study twisted derivations of cyclic group rings. Let
R
be a commutative ring with unity,
G
be a finite cyclic group, and (
σ
,
τ
) be a pair of
R
-algebra endomorphisms of the group algebra
RG
, which are
R
-linear extensions of the group endomorphisms of
G
. In this article, we give two characterizations concerning
(
σ
,
τ
)
-derivations of the group ring
RG
. First, we develop a necessary and sufficient condition for a
(
σ
,
τ
)
-derivation of
RG
to be inner. Second, we provide a necessary and sufficient condition for an
R
-linear map
D
:
R
G
→
R
G
with
D
(
1
)
=
0
to be a
(
σ
,
τ
)
-derivation. We also illustrate our theorems with the help of examples. As a consequence of these two characterizations, we answer the well-known twisted derivation problem for
RG
: Under what conditions are all
(
σ
,
τ
)
-derivations of
RG
inner? Or is the space of outer
(
σ
,
τ
)
-derivations trivial? More precisely, we give a sufficient condition under which all
(
σ
,
τ
)
-derivations of
RG
are inner and a sufficient condition under which
RG
has non-trivial outer
(
σ
,
τ
)
-derivations. Our result helps in generating several examples of non-trivial outer
(
σ
,
τ
)
-derivations.
Journal Article
A Review of Recent Passive Heat Transfer Enhancement Methods
Improvements in miniaturization and boosting the thermal performance of energy conservation systems call for innovative techniques to enhance heat transfer. Heat transfer enhancement methods have attracted a great deal of attention in the industrial sector due to their ability to provide energy savings, encourage the proper use of energy sources, and increase the economic efficiency of thermal systems. These methods are categorized into active, passive, and compound techniques. This article reviews recent passive heat transfer enhancement techniques, since they are reliable, cost-effective, and they do not require any extra power to promote the energy conversion systems’ thermal efficiency when compared to the active methods. In the passive approaches, various components are applied to the heat transfer/working fluid flow path to improve the heat transfer rate. The passive heat transfer enhancement methods studied in this article include inserts (twisted tapes, conical strips, baffles, winglets), extended surfaces (fins), porous materials, coil/helical/spiral tubes, rough surfaces (corrugated/ribbed surfaces), and nanofluids (mono and hybrid nanofluids).
Journal Article