•Explanation of the discrepancy between PMV and adaptive models is still wanting.•Various adaptive comfort standards are broadly consistent with the exception of GB/T 50,785 (China).•Building ...typology exerts a discernible effect on occupant comfort.•Boundaries of the comfort zone have become progressively narrower in recent decades.•No credible evidence supports the practice of overcooling buildings to 22 °C for cognitive performance benefits.
The rapid escalation of cooling demand in buildings set against the backdrop of a global climate emergency is intensifying research activity on adaptive thermal comfort. In this review of the topic spanning the last 21 years we examine progress or lack thereof, in various research themes. These include adaptive comfort theory, adaptive comfort practice (standards), contextual effects on adaptive comfort (building typologies), shifting boundaries of the comfort zone and the dynamics of comfort expectations. Lastly we assess the implications of adaptive thermal comfort for cognitive performance of building occupants.
This paper experimentally investigates multilayers corrugated core sandwiches under out-of-plane compressive impact loading. The manufacturing method of corrugated core sandwiches in our laboratory ...is presented at first and its mechanical behavior under quasi-static loading shows a good repeatability. A testing configuration on the basis of a 97mm diameter and 8m long Nylon Hopkinson pressure bar is proposed to host this large sandwich sample and to impose a nominal strain of 70% to multilayer sandwich samples of 45.5mm long. High-speed imaging system provides their deforming modes and reveals the interactions between adjacent layers. Finally, testing results on 1060 aluminum corrugated core sandwiches are obtained under quasi-static and impact loadings. Significant rate sensitivity is observed and it can be reproduced by the numerical simulation. The bending of the interlayer plate is also observed, which contributes to reduce the force oscillation during successive folding.
The anharmonic lattice dynamics of rock-salt thermoelectric compounds SnTe and PbTe are investigated with inelastic neutron scattering (INS) and first-principles calculations. The experiments show ...that, surprisingly, although SnTe is closer to the ferroelectric instability, phonon spectra in PbTe exhibit a more anharmonic character. This behavior is reproduced in first-principles calculations of the temperature-dependent phonon self-energy. Our simulations reveal how the nesting of phonon dispersions induces prominent features in the self-energy, which account for the measured INS spectra and their temperature dependence. We establish that the phase space for three-phonon scattering processes, combined with the proximity to the lattice instability, is the mechanism determining the complex spectrum of the transverse-optic ferroelectric mode.
Whistler waves that can produce anomalous resistivity by affecting electrons' motion have been suggested as one of the mechanisms responsible for magnetic reconnection in the electron diffusion ...region (EDR). Such type of waves, however, has rarely been observed inside the EDR so far. In this study, we report such an observation by Magnetospheric Multiscale (MMS) mission. We find large‐amplitude whistler waves propagating away from the X line with a very small wave‐normal angle. These waves are probably generated by the perpendicular temperature anisotropy of the ~300 eV electrons inside the EDR, according to our analysis of dispersion relation and cyclotron resonance condition; they significantly affect the electron‐scale dynamics of magnetic reconnection and thus support previous simulations.
Key Points
Whistler waves are observed inside the EDR by MMS
The whistlers are propagating away from the X line
The pancake distribution of electrons in the EDR generates the whistlers
Magnetic reconnection—the process responsible for many explosive phenomena in both nature and laboratory—is efficient at dissipating magnetic energy into particle energy. To date, exactly how this ...dissipation happens remains unclear, owing to the scarcity of multipoint measurements of the “diffusion region” at the sub‐ion scale. Here we report such a measurement by Cluster—four spacecraft with separation of 1/5 ion scale. We discover numerous current filaments and magnetic nulls inside the diffusion region of magnetic reconnection, with the strongest currents appearing at spiral nulls (O‐lines) and the separatrices. Inside each current filament, kinetic‐scale turbulence is significantly increased and the energy dissipation, E′ ⋅ j, is 100 times larger than the typical value. At the jet reversal point, where radial nulls (X‐lines) are detected, the current, turbulence, and energy dissipations are surprisingly small. All these features clearly demonstrate that energy dissipation in magnetic reconnection occurs at O‐lines but not X‐lines.
Key Points
Strong current, turbulence, and energy dissipation at O‐lines
No current, turbulence, and energy dissipation at X‐lines
The current‐driven turbulence at O‐lines leads to dissipation
The insulating honeycomb magnet α-RuCl_{3} exhibits fractionalized excitations that signal its proximity to a Kitaev quantum spin liquid state; however, at T=0, fragile long-range magnetic order ...arises from non-Kitaev terms in the Hamiltonian. Spin vacancies in the form of Ir^{3+} substituted for Ru are found to destabilize this long-range order. Neutron diffraction and bulk characterization of Ru_{1-x}Ir_{x}Cl_{3} show that the magnetic ordering temperature is suppressed with increasing x, and evidence of zizag magnetic order is absent for x>0.3. Inelastic neutron scattering demonstrates that the signature of fractionalized excitations is maintained over the full range of x investigated. The depleted lattice without magnetic order thus hosts a spin-liquid-like ground state that may indicate the relevance of Kitaev physics in the magnetically dilute limit of RuCl_{3}.
Abstract
Spin-valley locking in monolayer transition metal dichalcogenides has attracted enormous interest, since it offers potential for valleytronic and optoelectronic applications. Such an exotic ...electronic state has sparsely been seen in bulk materials. Here, we report spin-valley locking in a Dirac semimetal BaMnSb
2
. This is revealed by comprehensive studies using first principles calculations, tight-binding and effective model analyses, angle-resolved photoemission spectroscopy measurements. Moreover, this material also exhibits a stacked quantum Hall effect (QHE). The spin-valley degeneracy extracted from the QHE is close to 2. This result, together with the Landau level spin splitting, further confirms the spin-valley locking picture. In the extreme quantum limit, we also observed a plateau in the
z
-axis resistance, suggestive of a two-dimensional chiral surface state present in the quantum Hall state. These findings establish BaMnSb
2
as a rare platform for exploring coupled spin and valley physics in bulk single crystals and accessing 3D interacting topological states.
•Impact testing of corrugated core sandwiches with a property gradient.•Numerical analysis of corrugated core sandwiches with a property gradient.•Significant effect of property gradient at higher ...impact speed.•Strategy to place the “weakest” layer in contact with the protected structure.
Graded lightweight structure is a new trend to improve energy absorption capacity of such structural materials. This study aims at the influence of property gradients on the overall behavior of graded multilayer sandwiches with corrugated cores under impact loading. The design of the property gradient of graded multilayer sandwiches as well as the manufacturing of different corrugated cores is presented at first. The graded multilayer sandwich is tested under various experimental configurations at rather low (9 m/s) and high (38 m/s) impact velocities. It turned out that no influence of gradient is found for low impact velocity because a quasi-static equilibrium state is reached. However, at high impact velocity, the test revealed a significant difference between different property gradient profiles. Numerical models are also built to simulate those tests. It allows for the further numerical analysis on a larger range of gradient profiles and higher impact velocities. A general trend for the design of the graded multilayer sandwiches with corrugated cores to improve energy absorption efficiency is proposed, which consists of placing the weakest layer near the protected structure and the hardest layer near the impacted end of the graded sandwich.
The neuro-anatomical substrates of major depressive disorder (MDD) are still not well understood, despite many neuroimaging studies over the past few decades. Here we present the largest ever ...worldwide study by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) Major Depressive Disorder Working Group on cortical structural alterations in MDD. Structural T1-weighted brain magnetic resonance imaging (MRI) scans from 2148 MDD patients and 7957 healthy controls were analysed with harmonized protocols at 20 sites around the world. To detect consistent effects of MDD and its modulators on cortical thickness and surface area estimates derived from MRI, statistical effects from sites were meta-analysed separately for adults and adolescents. Adults with MDD had thinner cortical gray matter than controls in the orbitofrontal cortex (OFC), anterior and posterior cingulate, insula and temporal lobes (Cohen's d effect sizes: -0.10 to -0.14). These effects were most pronounced in first episode and adult-onset patients (>21 years). Compared to matched controls, adolescents with MDD had lower total surface area (but no differences in cortical thickness) and regional reductions in frontal regions (medial OFC and superior frontal gyrus) and primary and higher-order visual, somatosensory and motor areas (d: -0.26 to -0.57). The strongest effects were found in recurrent adolescent patients. This highly powered global effort to identify consistent brain abnormalities showed widespread cortical alterations in MDD patients as compared to controls and suggests that MDD may impact brain structure in a highly dynamic way, with different patterns of alterations at different stages of life.
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