The model of synchronization between internal reconnections and edge-localized modes

A new model for interaction between the internal reconnections caused by sawtooth and the edge-localized modes (ELM) was presented. The experimental evidence of the coupling between sawtooth crash and ELM events were observed in the Globus-M and Globus-M2 tokamaks. The numerical analysis of magnetic equilibrium showed that internal reconnections can induce the excess current density near the separatrix during the several hundreds of μs. The excess current destabilizes the peeling-ballooning instability. The peeling-ballooning stability analysis showed that the penetration depth of the induced current should be in the range of ψnorm = 0.8 - 0.95 to trigger the instability.

ANALISIS PENGENDALIAN KOROSI PADA PERMUKAAN BASAH KAPAL-KAPAL BAJA DENGAN MENGGUNAKAN ZINK ANODA

Zink anodes are very importantfor reducing the corrosion rate on underwater surface area of hull plates. Zink anodes are affixed to parts of the vessel that are prone to seawater corrosion. This study aims to find out how much influence the installed current has on the corrosion rate by analyzing the data on the use of zink anodes in the field and the data on the use of zink anodes as a result of calculations so that the use of strong currents installed according to the need will reduce the rate of corrosion. To see the strong influence of current on the rate of corrosion, it takes data on the corrosion rate of the last 5 years from 9 vessels and also the number of zink anodes used each year. From the graph of the results of the calculation of strong current according to the theory and the results of the use of zinc anodes on nine vessels, the results obtained it is clear that the installed current strength must meet the needs of each vessel because it will affect the decrease in corrosion rate. On vessel No.3, an excess current strength of 0.539Amp to 1,386 Amp, a decrease in corrosion rate reaching 0.0317 mm/year in the 5th year. On vessel No. 4, an excess current strength of 0.444 Amp to 1.822 Amp there is a decrease in corrosion rate reaching 0.0138 mm/year in the 5th year. On vessel No. 9, an excess strong current of 4,894 Amp to 5,793 Amp there is a decrease in corrosion rate reaching 0.0371 mm/year in the 5th year.

ELECTRONIC FUSE USING RESETTABLE POLY FUSE FOR OVER CURRENT PROTECTION

This paper presents a new technique to deal with the high load currents or fluctuating currents using poly fuse as its major component. Poly fuse is a resettable fuse which goes on increasing its resistance, blocking the excess current until the current is back to normal. Once the current is under normal conditions, the resistance stabilizes and the path between supply and load is reconnected. The proposed work also uses a reed relay which breaks the path exactly at the specified rating, allowing a fast switch. The combination of poly fuse and reed relay provides more efficient outputs as compared to traditional circuit breakers. The fast-switching action, accurate results and the smaller size makes poly fuse more suitable for most of the power devices.

A new method to correct the electrochemical concentration cell (ECC) ozonesonde time response and its implications for “background current” and pump efficiency

The electrochemical concentration cell (ECC) ozonesonde has been the main instrument for in situ profiling of ozone worldwide; yet, some details of its operation, which contribute to the ozone uncertainty budget, are not well understood. Here, we investigate the time response of the chemical reactions inside the ECC and how corrections can be used to remove some systematic biases. The analysis is based on the understanding that two reaction pathways involving ozone occur inside the ECC that generate electrical currents on two very different timescales. The main fast-reaction pathway with a time constant of about 20 s is due the conversion of iodide to molecular iodine and the generation of two free electrons per ozone molecule. A secondary slow-reaction pathway involving the buffer generates an excess current of about 2 %–10 % with a time constant of about 25 min. This excess current can be interpreted as what has conventionally been considered the “background current”. This contribution can be calculated and removed from the measured current instead of the background current. Here we provide an algorithm to calculate and remove the contribution of the slow-reaction pathway and to correct for the time lag of the fast-reaction pathway. This processing algorithm has been applied to ozonesonde profiles at Costa Rica and during the Central Equatorial Pacific Experiment (CEPEX) as well as to laboratory experiments evaluating the performance of ECC ozonesondes. At Costa Rica, where a 1 % KI, 1/10th buffer solution is used, there is no change in the derived total ozone column; however, in the upper troposphere and lower stratosphere, average reported ozone concentrations increase by up to 7 % and above 30 km decrease by up to 7 %. During CEPEX, where a 1 % KI, full-buffer solution was used, ozone concentrations are increased mostly in the upper troposphere, with no change near the top of the profile. In the laboratory measurements, the processing algorithms have been applied to measurements using the majority of current sensing solutions and using only the stronger pump efficiency correction reported by Johnson et al. (2002). This improves the accuracy of the ECC sonde ozone profiles, especially for low ozone concentrations or large ozone gradients and removes systematic biases relative to the reference instruments. In the surface layer, operational procedures prior to launch, in particular the use of filters, influence how typical gradients above the surface are detected. The correction algorithm may report gradients that are steeper than originally reported, but their uncertainty is strongly influenced by the prelaunch procedures.

Сезонний вплив на режими роботи електротехнічної системи протикорозійного захисту

This article discusses the change in the magnitude of the currents of cathodic protection stations with changing seasons. The change in the value of currents at a constant voltage of the stations is significant. The work draws attention to the fact that with excess current, wasteful use of resources is possible. Given that changes in electrical parameters are possible not only with changing seasons, but also under the influence of precipitation, groundwater level, technological factors, it is advisable to automatically control the cathodic protection station. The use of joint control by several cathodic protection stations is proposed, which will minimize their combined influence. Coordination of the operating modes of the stations is minimizes the wasteful use of resource.

Setting Kerja Waktu Relay Arus Lebih pada Penyulang Kikim di Gardu Induk Sungai Juaro

Intisari — Gangguan-gangguan yang sering terjadi pada operasi sistem tenaga listrik dapat mengakibatkan terganggunya penyaluran tenaga listrik ke konsumen, sehingga menimbulkan arus hubung singkat yang cukup besar, untuk menghindari akibat gangguan tersebut diperlukan perlindungan jaringan dengan memasang suatu relay proteksi. Tujuan dari penelitian ini adalah melakukan simulasi menggunakan software ETAP dan perhitungan arus hubung singkat serta setting waktu kerja relay arus lebih. Metode yang digunakan untuk menganalisis gangguan hubung singkat yaitu 1) identifikasi data, 2) simulasi, 3) perhitungan, 4) hasil dan analisis serta 5) kesimpulan. Hasil penelitian, simulasi software ETAP arus gangguan hubung singkat maksimum pada jarak 25% dengan arus gangguan tiga fasa sebesar 2877.341 A, dua fasa sebesar 2672.708 A, dan satu fasa sebesar 2491.835 A. Gangguan minimum pada jarak 100% dengan arus gangguan tiga fasa sebesar 502.032 A, dua fasa sebesar 434.671 A, dan satu fasa sebesar 347.035 A. Sedangkan untuk hasil simulasi waktu kerja relay arus lebih sisi incoming sebesar 1 detik dan sisi outgoing sebesar 0.55 detik, hasil perhitungan waktu kerja relay arus lebih sisi incoming sebesar 0.99 detik dan sisi outgoing sebesar 0.54 detik.Kata kunci — Gangguan Hubung Singkat, relay arus lebih, ETAP Power Station 12.6.0. Abstract — Interferences that often happen in an operation system of electric power can cause in disruption of distribution the electric power to consumers, so it causes quite large shor-circuit current. To avoid the impact of that inrerferences,setting relay portection to protect the network is needed. The purpose of the reserch is doing a simulation using ETAPsoftware, calculating the short-circuit current, and setting the working time of excess-current relay. The method that used to analyze the interferences of short-circuit current are : 1) data identifying, 2) Simulation, 3) calculation, 4) result and analysis and, 5) conclution. The results of the research show that the maximum interferences of short -circuit current at 25% of distance with three phase Interferences is 2877,341 A, two -phase is 2672,708 A, and one-phase is 2491,835 A. The minimum Interferences at 100% distance with three phase Interferences is 502,032 A, two -phase is 434,671 A, and one-phase is 347,035 A. And the result of the simulation time of excess-current relay on incoming side is 1 second and on feeder side is 0.55 second, the results of the calculation working time of excess-current relay on the incoming side are 0.99 second and on the feeder, a side is 0.54 secondKeywords— short circuit, over current relay, ETAP power station 12.6.0

Analisis Perputaran Modal Kerja Pada Pt Hanjaya Mandala Sampoerna,Tbk

Working capital is excess current assets againts short-term debt. This excess is called net working capital.The problem studied in this study is how much the working capital needs of PT Hanjaya Mandala Sampoerna, Tbkby using the working capital turnover formula.The conclusion of this study is that working capital is described using ratios Working Capital Turnoverwhich measures working capital turnover where the sale proceeds divided by working capital. Working capitalturnover in 2015 amounted to 9,89 % in 2016 amounted to 5,49 %, whereas in 2017 it was equal 2,05 % this showsthat there is an excess of working capital due to low receivables.Total corporate receivables in 2015 were lower than in 2016 and 2017 thus resulting in greater numberof attachments to the company’s working capital and faster working capital turnover.

Smoke emission and temperature characteristics of the long-term overloaded wire in space

We developed an experimental payload to study the overloaded characteristics of wire insulations on board the China’s SJ-10 satellite. In 2-week microgravity experiments provided by the orbital flight, the smoke emissions of overloaded wire insulations were observed in space for the first time. Two smoke emission modes, namely the end smoke jet and the bubbling smoke jet, were identified with polyethylene insulations. The results showed that the geometry of the pyrolysis front dominated the direction and the range of the end smoke jet. The non-oxidative pyrolysis that occurred between the wire core and the insulation produced the high-temperature smoke and caused the bubbling smoke jet. The bubbling jet has a significant impact on the temperatures of adjacent wires, revealing an additional fire risk in microgravity. The effects of insulation thickness and excess current on the temperature rise were also discussed.