Introduction of Low-Carbon Community Energy Systems by Combining Information Networks and Cogeneration-Type District Heating and Cooling Systems

Achievement of a low-carbon society is becoming extremely important. In this report, we introduce an example of carbon dioxide (CO2) emission reductions and energy savings, using a local energy-control system. Our research is focused on the town of Shinchi in the Fukushima Prefecture, Japan. Shinchi is pursuing initiatives to create a low-carbon, energy-efficient society and a disaster-resilient community. The National Institute for Environmental Studies provides academic support for the design and planning of low-carbon community energy systems by the local government of Shinchi, based on the Basic Cooperation Agreement. For the redevelopment of the Japan Railway (JR) Shinchi Station district that is being carried out, construction of a cogeneration-type district heating and cooling system is currently in progress. CO2 reductions of about 20% can be expected by introducing this community energy system. To support these initiatives, we have developed an information and communication technology (ICT) system that shares a wide range of local information to support energy conservation. By analyzing electricity consumption data from the ICT, we evaluated the pattern of residential power consumption and confirmed that the project supports energy-saving behavior within the community. Additionally, the community energy project in the JR Shinchi Station district enables adjustment of the supply and demand balance

Chiral phonons: circularly polarized Raman spectroscopy and ab initio\textit{ab initio} calculations in a chiral crystal tellurium

Recently, phonons with chirality (chiral phonons) have attracted significant attention. Chiral phonons exhibit angular and pseudo-angular momenta. In circularly polarized Raman spectroscopy, the peak split of the $\Gamma_3$ mode is detectable along the principal axis of the chiral crystal in the backscattering configuration. In addition, peak splitting occurs when the pseudo-angular momenta of the incident and scattered circularly polarized light are reversed. Until now, chiral phonons in binary crystals have been observed, whereas those in unary crystals have not been observed. Here, we observe chiral phonons in a chiral unary crystal Te. The pseudo-angular momentum of the phonon is obtained in Te by an $\textit{ab initio}$ calculation. From this calculation, we verified the conservation law of pseudo-angular momentum in Raman scattering. From this conservation law, we determined the handedness of the chiral crystals. We also evaluated the true chirality of the phonons using a measure with symmetry similar to that of an electric toroidal monopole

Wide-bandgap GaN-based watt-class photonic-crystal lasers

青色GaN系フォトニック結晶レーザーの高出力・高ビーム品質動作に成功 --次世代の高品位レーザー加工、高輝度照明、水中LiDAR等の実現に向けて--. 京都大学プレスリリース. 2022-11-04.Short-wavelength (blue-violet-to-green) lasers with high power and high beam quality are required for various applications including the machining of difficult-to-process materials and high-brightness illuminations and displays. Promising light sources for such applications are wide-bandgap GaN-based photonic-crystal surface-emitting lasers (PCSELs), which are based on two-dimensional resonance in the photonic crystal. Developments of these devices have lagged behind those of longer-wavelength GaAs-based PCSELs, because device designs for achieving robust two-dimensional resonance and a nanofabrication process that avoids introducing disorders have remained elusive for wide-bandgap GaN-based materials. Here, we address these issues and successfully realize GaN-based PCSELs with high, watt-class (>1 W) output power and a circular, single-lobed beam with a very narrow (~0.2°) divergence angle at blue wavelengths. In addition, we demonstrate continuous-wave operation with a high output power (~320 mW) and a high beam quality (M²~1). Our results will enable the use of GaN-based PCSELs in the above-mentioned applications

Truly chiral phonons in {\alpha}-HgS

Chirality is a manifestation of the asymmetry inherent in nature. It has been defined as the symmetry breaking of the parity of static objects, and the definition was extended to dynamic motion such that true and false chiralities were distinguished. Recently, rotating, yet not propagating, atomic motions were predicted and observed in two-dimensional materials, and they were referred to as "chiral phonons" . A natural development would be the discovery of truly chiral phonons that propagate while rotating in three-dimensional materials. Here, we used circularly polarised Raman scattering and first-principles calculations to identify truly chiral phonons in chiral bulk crystals. This approach enabled us to determine the chirality of a crystal in a non-contact and non-destructive manner. In addition, we demonstrated that the law of the conservation of pseudo-angular momentum holds between circularly polarised photons and chiral phonons. These findings are expected to help develop ways for transferring the pseudo-angular momentum from photons to electron spins via the propagating chiral phonons in opto-phononic-spintronic devices

Applying the functional resonance analysis method (FRAM) to flood risk management at a community level: Koriyama city's emergency-response process during Typhoon Hagibis

This study used the functional resonance analysis method (FRAM) to analyze a real-world example of an emergency-response process, one that occurred in Koriyama city, Japan, during Typhoon Hagibis (known in Japan as Typhoon No. 19, or Reiwa 1 East Japan Typhoon). The analysis revealed nine functions that constitute the municipality's emergency-response process (including Public Communication, Provision/Management of Evacuation Shelters, Evacuation, and Rescue Operations) as well as the interactive relationships between these functions. It also revealed how variabilities in the timeliness and accuracy of the functions resonated with (reinforced) each other, culminating in an incident involving a backlog of emergency calls. From these results, two recommendations were derived: reviewing the public communication system and building a framework for minimizing variability in evacuation behavior. And also, based on the FRAM analysis we could contextualize the interview data and the individual phenomena described fragmentally in the retrospective report (used for evaluating the disaster response), thereby gaining an understanding of the incident generation mechanism. In conclusion, the study demonstrated FRAM can be an effective tool for retrospective evaluation of disaster response or revising a disaster plan

The future of Southeast Asia’s forests

While Southeast Asia’s forests play important roles in biodiversity conservation and global carbon (C) balance, the region is also a deforestation hotspot. Here, we consider the five shared socioeconomic pathways (SSPs) to portray a range of plausible futures for the region’s forests, employing a state-of-the-art land change modelling procedure and remotely sensed data. We find that by 2050 under the worst-case scenario, SSP 3 (regional rivalry/a rocky road), the region’s forests would shrink by 5.2 million ha. The region’s aboveground forest carbon stock (AFCS) would decrease by 790 Tg C, 21% of which would be due to old-growth forest loss. Conversely, under the best-case scenario, SSP 1 (sustainability/taking the green road), the region is projected to gain 19.6 million ha of forests and 1651 Tg C of AFCS. The choice of the pathway is thus critical for the future of the region’s forests and their ecosystem functions and services.JRC.D.1-Bio-econom