Dust traps and the formation of cavities in transition discs: a millimetre to sub-millimetre comparison survey

ABSTRACT The origin of the inner dust cavities observed in transition discs remains unknown. The segregation of dust and size of the cavity is expected to vary depending on which clearing mechanism dominates grain evolution. We present the results from the Discs Down Under program, an 8.8-mm continuum Australia Telescope Compact Array (ATCA) survey targeting 15 transition discs with large (≳20 au) cavities and compare the resulting dust emission to Atacama Large millimetre/sub-millimetre Array (ALMA) observations. Our ATCA observations resolve the inner cavity for 8 of the 14 detected discs. We fit the visibilities and reconstruct 1D radial brightness models for 10 sources with a S/N > 5σ. We find that, for sources with a resolved cavity in both wavebands, the 8.8 mm and sub-mm brightness distributions peak at the same radius from the star. We suggest that a similar cavity size for 8.8 mm and sub-mm dust grains is due to a dust trap induced by the presence of a companion.

Clearing Model for Day-ahead Market Considering Hydraulic Coupling Relationship of Multi-operator Cascade Hydropower Stations

There is a hydraulic coupling relationship between the upstream and downstream of cascade hydropower stations, and they usually belong to different stakeholders. Traditional clearing mechanism may lead to the mismatch between the bid-winning power and the actual power generated by the downstream power stations, and the low-cost downstream power stations may lose some chance to generate, resulting in damage to social welfare. This paper analyzes the problems faced by multi-operator cascade hydropower stations participating in the day-ahead market. By deducing the generation coupling relationship between upstream and downstream cascade hydropower stations, it is found that the output of downstream hydropower stations can be divided into four parts: fixed part, adjustable part, the part coupled with the output of the upstream power station, the part coupled with the output of the upstream power station and the adjustable output. At last, day-ahead market clearing mechanism and settlement mechanism for downstream power stations to participate in bidding are proposed.

ANALISIS MEKANISME KLIRING PADA KANTOR PERWAKILAN (KPW) BANK INDONESIA (BI) LHOKSEUMAWE

This study aims to explain the clearing mechanism at Bank Indonesia Lhokseumawe City, to determine the constraints that occur in the clearing mechanism. This research is a field study or also called the type of field research, which is obtaining data from research objects by collecting data extracted from field data sources, namely from informants. The conclusions that the authors conclude in this study are as follows: 1. The clearing mechanism is carried out with several mechanisms, first, the company (the bank) sends payment data to the sending bank, second, the sending bank sends the transaction to the SKNBI the receiving bank receives transaction data and funds from the settlement, then third, the receiving bank verifies the name and account number of the customer recipient, if it is not appropriate, the director must be in bulk format, fourth, the recipient bank will forward the transaction to the customer's account The obstacle faced by BI in the clearing mechanism is the existence of network disruptions during the clearing process, so that Bank Indonesia needs to conduct bilateral transactions or clearing processes between banks using the RTGS system. Network disruption can occur nationally or locally experienced by each region or office, especially the Bank in Lhokseumawe City. Keyword: Clearing Mechanism, Bank Indonesia. Abstrak Penelitian ini bertujuan untuk menjelaskan mekanisme kliring di Bank Indonesia Kota Lhokseumawe, untuk mengetahui kendala yang terjadi pada mekanisme kliring. Penelitian ini adalah penelitian lapangan atau disebut juga jenis penelitian lapangan, yaitu memperoleh data dari objek penelitian dengan mengumpulkan data yang diambil dari sumber data lapangan, yaitu dari informan. Kesimpulan yang penulis simpulkan dalam penelitian ini adalah sebagai berikut: 1. Mekanisme kliring dilakukan dengan beberapa mekanisme, pertama, perusahaan (bank) mengirim data pembayaran ke bank pengirim, kedua, bank pengirim mengirim transaksi ke SKNBI bank penerima menerima data transaksi dan dana dari penyelesaian, kemudian ketiga, bank penerima memverifikasi nama dan nomor rekening penerima pelanggan, jika tidak sesuai, direktur harus dalam format massal, keempat, bank penerima akan meneruskan transaksi ke rekening nasabah. Kendala yang dihadapi BI dalam mekanisme kliring adalah adanya gangguan jaringan selama proses kliring, sehingga Bank Indonesia perlu melakukan transaksi bilateral atau proses kliring antar bank menggunakan sistem RTGS. Gangguan jaringan dapat terjadi secara nasional atau lokal oleh masing-masing wilayah atau kantor, terutama Bank di Kota Lhokseumawe. Kata kunci: Mekanisme Kliring, Bank Indonesia.