bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a superconducting transformer for high current conductor testing
Authors: Ma H J , Liu H J , Shi Y , Liu F , Chen H , Zhang X T , Lei L
Published: June 2020

Critical current (Ic) tests on superconducting conductors require currents on the order of tens of kilo-amperes in combination with sub-microvolt resolution voltage measurements. Instead of traditional expensive DC power supply and complicated current leads, a superconducting transformer has been developed to feed the test sample with current up to 30 kA. The transformer consists of two concentric layer-wound superconducting solenoids with the primary coil inside the secondary. In order to reduce the influence by stray field of background magnet and transformer, a hall array with two hall sensors symmetrically distributed around the secondary conductor is used to achieve accurate secondary current measurement. This paper describes the design and manufacturing of transformer, including accurate secondary current measurement method. The first test results are also presented. The superconducting transformer system enables fast, high resolution, economic and safe tests of high current conductors.
AC Losses Analysis in stack of 2G HTS tapes in a coil
Authors: Zubko V V , Fetisov S S , Zanegin S Yu , Vysotsky V S
Published: June 2020

The model coil with the racetrack geometry based on second generation (2G) High Temperature Superconducting (HTS) tapes has been developed for an electrical machine where a winding pack is a stack of 2G HTS tapes. It is important to evaluate transport current AC losses and possible methods to reduce them in a winding. In a device made of 2G HTS tapes, the main the AC losses are the hysteresis ones. Only numerical simulation permits to predict them in full. The FEM model for calculation of the hysteresis losses developed before for 2G HTS power cables was modified for a stack of the 2G HTS tapes in a coil. In this paper the methods to increase a computational speed are presented. Possible ways to reduce AC losses are discussed also. The details of the model and comparisons of calculations with measurements of the AC loss are presented.
Magnetic shielding of long paraboloid structures in the inhomogeneous magnetic field
Authors: Kvitkovic J , Burnside K , Zhang M , Pamidi S
Published: June 2020

Shielding efficacy of the high-temperature superconducting (HTS) magnetic shields depends on the superconductor properties and on the orientation of the external magnetic field. For precise magnetic field measurements in areas with changing direction of magnetic noise it is important to reduce both the parallel and perpendicular components of the magnetic field. We have designed and fabricated magnetic shields of 25 cm long paraboloid shape with closed sides from second-generation HTS tapes. We have characterized HTS shields in DC and variable frequency AC magnetic fields at 77 K above a copper electromagnet acting as the source of inhomogeneous magnetic noise. The HTS magnetic shields reduce the magnetic field noise penetration and enhance the sensitivity of magnetic field sensors. The measurements were performed with the magnetic shield placed between the noise source and the sensor. 2D finite element analysis using Comsol model was generated and the results were compared with the experimental data of magnetic field dependences of the shielding factor (SF).
Study on conditions to reuse quenched HTS coil
Authors: Toriyama H. , Nomoto A. , Ichikawa T. , Takao T. , Nakamura K. , Tsukamoto O. , Furuse M.
Published: June 2020

An HTS coil quenches despite of the high quench margin. Main origins of unexpected quench of HTS coils are non-reversible local defects, and training effects as in LTS coils are not observed in HTS coils. Therefore, when an HTS coil is quenched before the required coil performance is met, the coil cannot be reused unless the coil is safely protected from quench damage and its operating conditions are readjusted. This paper studies on the conditions to reuse the coil which experienced a quench and is not damaged by the quench to meet the required performance. The study is conducted based on the temperature and current dependences of the coil stability measures of the maximum allowable defect (MAD) and minimum propagating zone (MPZ).
Development of a 20 T 100 mm Cold Bore Superconducting Magnet System
Authors: Ma W , Hollis T , Viznichenko R , Twin A , Clarke N , Warren D
Published: June 2020

Oxford Instruments has successfully developed a series of large bore, high field magnet systems, using conventional NbTi and Nb3Sn low temperature superconductors (LTS). These magnet systems built to date have cold bores ranging from 150 mm to 250 mm diameter with central field from 15 T to 19 T. In this paper, we will introduce the development of a new member of high field and large bore magnet system at Oxford Instruments, with a central field of 20 T and cold bore of 100 mm. The magnet will be integrated with a special low-loss cryostat, generally stainless-steel construction with conductive radiation shields, constructed to minimize eddy currents and reinforced to withstand induced forces in the event of a magnet quench. The key technical challenges which must be met to provide such magnet system will be discussed in this paper.
Magnetic Field Leakage of HTS Medical Accelerators
Authors: Baird Yvonne T E , Li Quan
Published: June 2020

A high temperature superconducting (HTS) magnet used in medical accelerators was designed with combined function for bending and focusing/defocusing, through a layer-by-layer design process. The six-layer combined function magnet produced by the layer-by-layer design process reduces the total volume of HTS material required compared to existing designs, in addition to achieving a precise field. The magnetic field distribution and leakage from the coil ends of the designed combined function magnet were studied, and the effects of changing the length of the coil ends as well as the radius of the layers were compared to the original design, to determine what influence this would have. Results show that shorter coil ends have the smallest leakage magnetic field, and is thus preferred, however due to mechanical constraints of HTS tape there will be a minimum length requirement depending on the design.
Feedforward current control of MRI magnet with power supply driven operation
Authors: Kitada S. , Sakamoto R. , Shirai Y. , Yokoyama S
Published: June 2020

We have been developing a conduction cooled 3T HTS(REBCO)-MRI system. The prototype system of 100 mm DSV (diameter spherical volume) was designed and made.The MRI image of a mouse fetus (25 mm long) was obtained successfully with 2.9 T under a power supply driven operation. However, the HTS(ReBCO)-MRI magnet still had a considerable magnetic field fluctuation for clear MRI imaging due to a long-lasting attenuation of screening current induced on the superconducting tapes. To solve this problem, we introduced a power supply system consists of a exciter power supply and a small trimming current supply, which compensates the magnetic field deviation due to the screening current, in parallel. We measured and evaluated the magnetic field stability of a commercial 3T-LTS-MRI magnet under both the power supply driven operation with proposed system and the persistent current operation. The availability of the power supply system was discussed using an experimental HTS-MRI system.
A target field approach to optimize cylindrical shim coils for superconducting MRI system
Authors: Wu Kaihong , Shi Yi , Wu Yu , Xu Aihua , Hao Qiangwang , Dai Chao , Ma Yuanyuan , Zhang Yongliang , Hussain Muhammad Talib
Published: June 2020

Target field method is used to design a specific form of the magnetic field which has been verified in many works of literature. And to restrict the current distribution on a rectangular or cylindrical surface with finite size, the current density is usually expanded by Fourier series with some unknown coefficients, which can be determined by setting the target-field points over the imaging region of interest, and then comparing the calculated field values from the Biot–Savart law and the ideal ones. The stream-function method is adopted to discrete the current density to generate winding patterns. But some design results can’t match the predetermined ones. Based on it, this paper proposed a new strategy for cylindrical shim coil design. Finally it can make the final design values meet the ideal fields with limited errors. This method can also be used to design gradient coils for high field superconducting MRI systems.
Development of a Half-Size 3 T REBCO Superconducting Magnet for MRI
Authors: Miura H , Matsuda T , Nomura K , Inoue T , Morita Y , Eguchi R , Otake S , Tanabe H , Yokoyama S , Sato S
Published: June 2020

We have been developing a liquid-helium-free 3T magnet for MRI using high-temperature superconducting (HTS) wires in a HTS application project supported by the New Energy and Industrial Technology Development Organization (NEDO). A half-size 3T-MRI magnet, which has 220 coils each of order meter size, has been manufactured in order to demonstrate MR imaging. 269 REBCO single-pancake coils were manufactured. We investigated the yield rate of meter-class REBCO coils by experiment and the degraded state of coils by calculation. It was found that the yield rate was 82 % and the degraded length was order millimeter size in total length of coil, which was several hundred meters. We will consider the factors of coil degradation and how to increase the yield rate of a REBCO coil.
Simulation of AC losses in racetrack coils wound with striated HTS tapes
Authors: Bianchetti M , de Bruyn B J H , Krop D C J , Lomonova E A
Published: June 2020

The T-A formulation has proved a fast and reliable method for the evaluation of AC losses in superconducting tapes, and has been successfully applied to complex geometries such as racetrack coils, CORC® cables, and twisted stacked tapes conductors in either applied magnetic field or self-field. In particular the T-A formulation was used for the evaluation of AC losses in CORC® cables made of striated superconducting tapes in an external applied field, with a null transport current. In this paper, the T-A formulation is adopted to evaluate the AC losses of stacked striated HTS tapes, representative of the straight section of a racetrack coil, with a sinusoidal transport current.
Quench protection of the BabyIAXO magnet
Authors: Bykovskiy N. , Dudarev A. , Silva H. , ten Kate H. H. J.
Published: June 2020

BabyIAXO, a 20 m-long twin-bore helioscope aiming for search of axion like particles, is currently in the engineering design phase and its construction is to be completed within the next 4 years. In addition to X-ray detectors and focusing optics, the system is equipped with a 50 MJ magnet with a common coil layout, containing two 10 m-long NbTi flat racetrack coils cooled by a group of cryocoolers. It has to operate at 10 kA, preferably in persistent mode with disconnected power supply, allowing to simplify the sun-tracking rotation system of BabyIAXO. A direct current mode is possible as well. Hence, quench protection is a high priority. Here, we present the electrical circuit of the BabyIAXO magnet and its protection layout when operated in persistent mode. The quench process is calculated using a 3-D thermo-electrical model of the coil windings, also accounting for the presence of the coil casing and the quench-back effect. Impact of the operating current, conductor properties, voltage detection threshold and location of hot-spot on the peak temperature is discussed. Quench protection aspects of the HTS busbars and persistent mode switch are also addressed.
AC losses and induced fields in HTS coil wound using two-ply coated conductors
Authors: Yokoyama H , Zhu B , Kajikawa K , Awaji S , Badel A , Takahashi K , Okada T
Published: June 2020

AC losses and screening-current-induced fields (SCFs) in a high temperature superconducting (HTS) inserts for high field magnet are evaluated theoretically. The HTS inserts are composed of stacked pancake coils, which are wound using two-ply conductors, where the superconducting-layer sides of two rare-earth-based coated conductors are attached to each other without electrical insulation. The theoretical formulas of AC loss and SCF in the two-ply conductor are derived for the simultaneous applications of a transport current and an external magnetic field parallel to its broad face. By taking into account the magnetic-field profile in the HTS insert and the magnetic-field dependency of critical current density in the coated conductor, the AC losses and SCFs are estimated using the theoretical formulas for monotonical increase in a central field up to 25.5 T in 60 minutes in combination with low temperature superconducting outsert coils. It is guessed that the AC loss estimated for the HTS insert wound using the two-ply conductor could be cooled by using prepared cryocoolers. The magnitude of SCF in the HTS insert wound using the two-ply conductor becomes smaller than that for the single-tape conductor estimated previously.
Adoption of getter pump for HTS superconducting cable system
Authors: Watanabe M , Masuda T , Yamaguchi H , Tanazawa M , Mimura T
Published: June 2020

For the superconducting cable operation in the real grid for over decades, one of the important technical challenges is maintaining vacuum rate of the thermal insulation cryostat vessels for avoiding system heat loss increase. When the vacuum rate is getting worse, turbo-molecular pumps etc. are usually adopted for that system. However, these pumps need to have some installation space and some electricity for the operation and moreover, periodic troublesome maintenance is needed. For the countermeasure of such issues, getter pump is selected and tested because of its smaller size, less electricity consumption and easy maintenance features. After confirming its effectivity as the vacuum pump by several investigations, this pump was employed for the termination vacuum vessel of the superconducting cable system in Yokohama. From the results of 3 weeks operation, evacuating performance exceeds turbo molecular pump and keeps vacuum state less than 1e-3 Pa stably, are confirmed respectively. This paper describes test results of the getter pump and its operation results for the real in grid system.
Design optimization of high-voltage HTS three-phase cables with screened phases
Authors: Arkhangelsky A Yu , Balashov N N , Degtyarenko P N , Kopylov S I , Zheltov V V
Published: June 2020

Design versions of HTS cables with the screened phases ensuring the AC losses minimization have been investigated by the numerical simulation methods. The following methods of optimization have been proposed: sectioning of phases, using of HTS tapes with the modified configuration and variation of the phase diameter. At the critical current of a phase of 5.1 kA and its rated current of 4 kA, these methods allow lowering of AC losses level to 0.45 – 0.017 W/m what is much lower than natural heat fluxes into a cryostat. The designs proposed are compared with ones of the optimized tri-axial cables what allows a reasonable choosing of a cable type vs. a given electric power system design.
Effect of HTS stack sectioning on pulse magnetization efficiency in a motor
Authors: Smara A , Climente-Alarcon V , Mineev N , Tomkow L , Glowacki B A
Published: June 2020

Stacks of HTS superconductors can be magnetized and used as a surface mounted magnet for electrical machines. Pulse field magnetization is considered as a practical method; however, the amplitude of the pulse can be limited in an electrical motor which results in an under-saturated stack with the superconducting currents penetrating only a part of it making the magnetization less efficient. A solution to this problem could be sectioning the stack along its width enabling effective penetration of the superconducting currents. In this paper we investigate the effect of sectioning of HTS surface mounted stacks on the efficiency of pulse magnetization method in trapping the flux using low pulsing field. It is shown that the sectioning of wide stacks into several narrower parts results in a higher trapped flux at low pulses. Experimental measurements are performed on a lab-scale motor to validate the theoretical analysis.
Development and testing of 10 kW fully HTS generator
Authors: Kovalev K , Ivanov N , Zhuravlev S , Nekrasova Ju , Rusanov D , Kuznetsov G
Published: June 2020

Electrical machines on the base of high temperature superconductors (HTS) could provide high specific (kW/kg) and volumetric (kW/m3) power. The most promising of them are fully HTS machines. Significant number of parameters and factors which have an impact on HTS windings make analytical analysis of the machine very complex. In this paper description of the prototype of fully HTS electrical machine is provided. Manufactured prototype was tested, experimental and calculation results were compared. In particular, open circuit performance is in good correlation with theoretical conclusions. Besides, results of experimental research of 15 HTS coils are provided. Some design features of the prototype are described.
Fault Current Limitation Coordination of Multiple SFCLs in IEEE 14-Bus Test System
Authors: Hayakawa N , Mori Y , Kojima H
Published: June 2020

We have proposed the concept of “fault current limitation coordination” of multiple superconducting fault current limiters (SFCL) to be introduced in a future electric power grid. Using a simplified test system, the transients on fault current and internal phase angle of generators were analyzed by PSCAD/EMTDC and the modeling of resistive SFCL with a variable resistance as a function of both current and temperature at the recovery under load. In this paper, we extended the analyses to the fault current limitation coordination of multiple SFCLs in IEEE 14-bus test system. The effective coordination strategy on the introduction and operation of multiple SFCLs, e.g. introduction lines of SFCLs, operation parameters such as operating current, critical current and prospective fault current of each SFCL, was discussed and optimized for an arbitrary fault location in the test system.
Study on Improvement of Recovery Characteristics of GdBCO Non-inductive coil for resistive SFCL
Authors: Yanai S. , Maeda C. , Shirai Y. , Shiotsu M. , Isojima S.
Published: June 2020

Using the practical application of the resistance SFCLs (Superconducting Fault Current Limiter), it is required to quickly return to the superconducting state after interruption of the fault current. The quick recovery needs to improve the cooling property of a superconducting tape. It is confirmed that the recovery characteristics of a superconducting tape can be improved by the PTFE (PolyeTetraFluoroEthylene) coating or applying pressure. In this paper, we used GdBCO tapes for the resistive SFCL and investigated the effect of the PTFE coating or applying pressure for improvement of its recovery characteristics of non-inductive coil. Besides, we observed the boiling phenomena on the surface of the part of GdBCO tapes between under pressurized conditions and ambient pressure by a high-speed video camera.
AC losses test of HTS racetrack coils for HTS motor winding
Authors: Zanegin S Yu , Ivanov N S , Shishov D M , Shishov I M , Kovalev K L , Zubko V V
Published: June 2020

Current work is dedicated to determination of AC losses of racetrack coils that are intended to be used in HTS motor winding. Coils were tested at temperature of boiling nitrogen with sine waveform current with frequencies from 50Hz to 200Hz and corresponding levels were taken as a basis for comparison. Current waveforms, distinctive for brushless DC and brushless AC motors, induced by high-frequency modulation, were compared. Two coils with same dimensions and numbers of turns, but with different tapes (AMSC/SuperOx) were compared in terms of the levels of losses on described current forms.
Winding Configurations and AC Loss of Superconducting Synchronous REBCO Motors
Authors: Kawagoe Akifumi , Kudou Kazuma , Kanemaru Ryota , Iwakuma Masataka , Konno Masayuki , Tomioka Akira , Izumi Teruo
Published: June 2020

We investigate effects of armature winding configurations on properties of fully superconducting synchronous motors using REBCO tapes. The effect of the configurations on ac losses in the winding tapes due to the changing transvers magnetic fields applied to the tapes in direction of perpendicular to the flat face of the tapes is important. In generally, it is effective to close winding factor to 1 for improvement of properties of motors. For the purpose, the shape of armature windings is better saddle-shaped winding than race-track winding. In this paper, numerical calculations on the properties of fully superconducting synchronous motors using REBCO tapes with 500 kW class were described. Operating temperature was 65 K. In order to demonstrate the feasibility of saddle-shaped winding, test coil with 5 turns were wound with YBCO tapes and then critical current measurements were carried out. The degradation of the properties has not observed.
SMALL-SCALE PROTOTYPE OF A FULLY HTS-2G SIX-PHASE INDUCTION ELECTRICAL MACHINE
Authors: Dezhin D , Dezhina I , Ilyasov R
Published: June 2020

HTS direct drive generators with high specific output mass power and specific output volume power (at the boiling point of liquid nitrogen 77 K) are needed for aviation. Elimination of the reduction unit will reduce the weight of the entire generation system. However, this puts high demands on the strength of the high-speed rotor. Other important requirements are: brushless; the possibility of adjusting the output voltage (by changing the excitation current) depending on the magnitude and type of the connected load; autonomy (no external power supply of excitation current). To satisfy all the above requirements, a fundamentally new technical solution for an electric machine was developed. The generator is a two-package hybrid of the Induction machine with combined excitation. HTS-2G windings (2x3-phases of HTS-2G armature windings and axial excitation coil) are in stationary cryostats on the stator. The rotor has alternating poles of high coercive permanent magnets and ferromagnetic poles. To ensure the alternating magnetic field of the poles of the rotor and to avoid demagnetization of permanent magnets by a counter-directed field of the axial excitation HTS coils, the rotor packages are rotated by one pole. In this case, the demagnetizing part of the axial flux is intercepted by the ferromagnetic pole of the neighboring packet.
Excitation Characteristics of MgB2 Race-track Coil Immersed in Liquid Hydrogen
Authors: Iwami Y. , Matsumoto T. , Hara S. , Shirai Y. , Shiotsu M. , Kobayashi H. , Naruo Y. , Nonaka S. , Inatani Y. , Tanaka H. , Kodama M. , Suzuki T.
Published: June 2020

Our research group has been researched for developing MgB2 superconducting energy apparatus in liquid hydrogen immersion cooling, such as superconducting generators.

In this study, two-pole MgB2 race-track coil, which was a model for a few tens kVA superconducting generator field magnet, was designed and made. This coil consists of two pieces of a similar MgB2 race-track coil which has 529 turn with straight section of 150 mm, bending diameter in the end of section of 100 mm and thickness of 34 mm. We carried out excitation tests of the coil immersed in liquid hydrogen at the temperature of 21 K to 32 K, and the load line of the coil was obtained. The critical current under self-field was obtained for various temperatures. The normal zone propagation behavior of the coil at the quench was also investigated using several potential taps installed in the coil.
Trapped-flux magnets characterization for application in synchronous machines
Authors: Climente-Alarcon V , Smara A , Mineev N , Tomkow L , Glowacki B A , Reis T
Published: June 2020

Trapped-flux magnets comprising stacked superconducting tape constitute a promising development to increase the power density of electrical machines, whilst at the same time keeping the complexity required in their construction in manageable levels that allow their use in applications such as aircraft propulsion.

However, the conditions in which superconducting stacks operate inside an electrical motor differ quite significantly from the materials characterization experiments commonly developed to model their behaviour. This work presents the results of studying the applicability of these devices as magnetic flux source in the rotor of synchronous machines considering the influence of whole magnetic circuit. Several aspects are assessed, such as flux harmonics, magnetization, losses and demagnetization. Analytical expressions, which provide limited accuracy but allow fast calculations, are used for this purpose. The results illustrate the different trade-offs that arise during the design of a synchronous electric motor using trapped-flux magnets.
Early detection of Indonesian financial crisis using combination of volatility and Markov switching models based on indicators of real exchange rate and M2/foreign exchange reserves
Authors: Nafisah N , Sugiyanto  , Pratiwi H
Published: June 2020

The financial crisis that occurred in the middle of 1997 and 2008 had a significant impact on the economy of Indonesia. To minimize the impact of the crisis, an early detection system that can detect some signs of a financial crisis is needed so that the relevant departments can apply some appropriate policies. The crisis occurred due to several macroeconomic indicators which reached very high fluctuation and changing condition. The combination of volatility and Markov switching models could explain the crisis. The indicators of the real exchange rate and M2/foreign exchange reserves from January 1990 to June 2018 were used to build such combined model. The results showed that the best model of real exchange rate and M2/foreign exchange reserves are MS GARCH (2,1,1). Real exchange rate indicator could explain the crisis in 1997 and 2008 periods, while the M2/foreign exchange reserves indicator could only explain the crisis in 1997. The predicted value of smoothed probability of real exchange rate and M2/foreign exchange reserves indicators showed that by the end of 2019 and early 2020 there will be no signs of a financial crisis in Indonesia.
Financial crisis prediction in Indonesia using combined of volatility and Markov switching models based on real interest rate on deposit and nominal exchange rate indicators
Authors: Rojanah D , Sugiyanto  , Zukhronah E
Published: June 2020

The financial crisis has happened Indonesia 1997 and 2008. The crisis had brought the disadvantages impact on the economy of Indonesia. To anticipate the impact of the crisis, an early detection system that can detect some signs of a financial crisis is needed so that the government as a decision maker in maintain the stability of the economy. The crisis occurred due to hight volatility and structural changes in macroeconomic indicators. One of model that can be used to captured signals crisis is a combination of volatility and Markov switching. Fluctuations can be explained using volatility model, while some changes in conditions are explained through Markov switching. This study uses indicators of the real interest rate on deposit and nominal exchange rate to detect signals crisis in Indonesia. The results showed that the MS-ARCH(2,1) models of the real interest rate on deposit could only explain the crisis that occurred in 1997 and the MS-GARCH(3,1,1) models of nominal exchange rate could explain the crisis that occurred in 1997 and 2008. Based on the predicted value of smoothed probability, it shows that from July 2019 to June 2020, there are no signals of financial crisis in Indonesia.
The application of combined Markov regime switching and volatility model in detecting early financial crisis in Indonesia
Authors: Ratnasari A P , Sugiyanto  , Subanti S
Published: June 2020

The financial crisis had occurred in Indonesia in the middle of 1997 to 1998 which caused the economy of Indonesia was down suddenly. Because the crisis occurred suddenly and even unexpectedly, the Indonesian government was not ready to deal with it. Therefore, the Indonesian government needs a system that can detect crisis signals; so that, such a financial crisis can be avoided. Export and import indicators have high fluctuation and regime-changing during a crisis so that they also can be used to detect crisis signals. The volatility model is able to explain the volatility which included in the indicators, while the Markov regime switching model can explain the regime-changing. Furthermore, a method that can be used to detect a crisis is the combination of Markov regime switching and volatility model. The value of smoothed probability obtained from the combination of those models is able to detect the financial crisis in Indonesia. The results show that export and import indicators can be modelled successively using MRS-GARCH (2,1,1) and MRS-ARCH (2,1). The results obtained from the prediction of those two models show that there is no financial crisis signal in Indonesia for a year later.
The prediction of financial crisis in Indonesia based on the smoothed probability value from the combination of volatility and Markov switching models
Authors: Pratiwi S D , Sugiyanto  , Pratiwi H
Published: June 2020

Indonesia is a country that applies an open economic system. The application of an open economic system can lead to the transmission of crises from other countries, for example the major financial crisis that experienced by Indonesia in 1997 and 2008. The financial crisis caused disruption to the economy stability of the country itself, so it is necessary to predict the financial crisis with the aim to protect economy stability. The indicators used in this research are the Indonesia Composite Index (ICI) and foreign exchange reserves. The method used is a combination of volatility and Markov switching models, namely the MS-ARCH(2,1) for ICI indicator and MS-GARCH(2,1,1) for foreign exchange reserves indicator. The result showed that based on the smoothed probability value of the combination of those two models, the ICI indicator could explain the crisis that occurred in 1997 and 2008, while the foreign exchange reserves indicator could only explain the crisis that occurred in 1997. In addition, the results of financial crisis prediction in Indonesia show that Indonesia will not experience a financial crisis for the next year. However, if the ICI and foreign exchange reserves indicators decrease by at least 32%, a crisis can occur.
Application of GSTAR kriging model in forecasting and mapping coffee berry borer attack in Probolinggo district
Authors: Pramoedyo H , Ashari A , Fadliana A
Published: June 2020

Generalized Space Time Autoregressive (GSTAR) is one of multivariate time series modeling that considers aspects of location with heterogeneous location characteristics. The GSTAR model normally can only be used in forecasting an event in the future at the observed locations. The problem that often occurs in some cases is that there are locations to be modeled that do not have sufficient or incomplete data as data in other locations. For this reason, several alternatives can be done, and one of them is by combining the GSTAR model with the kriging interpolation technique. This modeling is known as GSTAR Kriging modeling. In this research, GSTAR Kriging modeling is applied in predicting and mapping coffee berry borer attacks in Probolinggo District. The model parameters are estimated using the GLS method in the SUR equation system. Forecasting results indicate that the GSTAR Kriging model has a high forecasting accuracy and is not much different from the GSTAR model. Meanwhile, based on the forecasting map, it can be seen that the peak of coffee berry borer attack is predicted to occur in July 2019 with the attack center located in Tiris Sub-district.
Initial soil properties of the restored degraded area under different vegetation cover in UB Forest, East Java, Indonesia
Authors: Yusuf M , Fernandes A A R , Kurniawan S , Arisoesilaningsih E
Published: June 2020

Forest ecosystem degradation due to conversion into agricultural land is increasingly widespread in tropics. This study aimed to determine the initial properties of forest soils in some restoration areas under different vegetation cover. The restoration sites were divided into three areas, namely intensive agricultural land (PI), abandoned coffee plantation (KTT), and remnant protected forest (HLS). In each restoration area, soil samples were taken at top 20 cm depth of soil from five sampling points with three replications. As a comparison, soils were also sampled from the reference sites (RS). Soil samples were then analyzed for some soil properties in the laboratory such as soil physical properties (soil aggregate, bulk density, soil moisture), soil chemical properties (organic matter, pH, electrical conductivity), and soil biological properties (soil bacteria). Results showed that soil physical and chemical properties measured in restoration areas were significantly different from RS (p<0.05). Soil physics properties among three restoration areas were not statistically different (p>0.05), but the soil chemical properties were statistically different. This soil chemical difference was presumably caused by spatial variation and vegetation cover. The diversity of soil bacteria in all studied areas was not statistically different (p<0.05) even though the environmental conditions in each area were different. Among soil properties showed interactions that affected each other based on multivariate data analysis. Forest conversion into agricultural land use had a negative impact on soil properties and tends to decrease soil quality and health.
Combination of extraction features based on texture and colour feature for beef and pork classification
Authors: Priyatno A M , Putra F M , Cholidhazia P , Ningsih L
Published: June 2020

Behaviour of traders mixing beef and pork is very detrimental to consumers, especially followers of Islam because it is related to legal or forbidden food. So, consumers must be protected from these rogue traders. However, differentiating beef and pork is not easy for ordinary people, especially if you only see from one information that is the colour or texture. In this paper, we proposed a new combination of extraction features based on texture and colour features for the classification of beef and pork. The feature of the texture is to see the local information optimally by using a local optimal-oriented pattern (LOOP) so that it can provide better texture information. The colour features that will be used are hue, saturation, and value (HSV). Texture and colour features are combined into one, so that more enrich the information used. The combination of optimal local-oriented pattern features and hue saturation value gives increased accuracy for the classification of pork and beef. The results of tests that have been done show that the success rate of calcification by using a combination of features has increased. accuracy obtained is equal to 99.16 percent, recall 100 percent and precision 98.36 percent. this shows that by utilizing the colour features and texture features can provide improved classification due to increased information that can be used to do the classification.
Integration of photosystem I and photosystem II from tylakoid membrane of spirulina sp. for DSSC natural dye pigments
Authors: Kusuma D Y , Hidayah Q , Izziyah A N , Purnama B
Published: June 2020

Conversion of sunlight to electron within pigment-protein complex of Photosistem I (PS I) and Photosystem II (PS II) in kloroplast's tylakoid membrane is the hearth of photosynthesis process. This process is very efficient with nearly 100% quantum efficiency. In this paper, we demonstrate the integration of PS I and PS II pigment-protein complex extracted from spirulina sp, as the natural dye for DSSC structure. The PS I and PS II was obtained by ultrasonic cell rupture followed by staggered sequential centrifugation at various g-force level to separate the tylakoid protein complex from other cell components. Contrary to typical DSSC using inorganic dyes which requires elaborate surface treatment, expensive, and employing hazardous dyes, the devices described here are straightforward and inexpensive to fabricate. The device also perform well on photovoltaic activity yielding open circuit voltage of 0.20 V, short-circuit current density of 7.60 μA, and fill factor of 35% at 1 mW/cm2 incandescence lamp illumination.
Response of seed germination and seedling growth of Physalis accession from East Java
Authors: Mastuti R , Waluyo B , Batoro J
Published: June 2020

Environmental conditions significantly affects response of seed germination. This study aims to determine ex vitro and in vitro seed germination capacity and seedling growth of accession of Physalis sp derived from East Java including Madura Island. Ex vitro germination was carried out in mixed soil media: compost: husk charcoal while in vitro germination was carried out in agar-solidified medium. Ex vitro germinated seeds are generally able to produce 80-100% seedling in all accessions. Accessions from Madura Island have a better growth response compared to accessions from East part of Java Island. Although in vitro germination response was lower, the four accessions from the island of Madura namely A1 (Sumenep), A2 (Sampang), A4 (Sampang) and A5 (Pamekasan) have been able to produce regeneration and multiplication of shoots in vitro. The potential for in vitro growth in Physalis accessions needs to be developed to supply germplasm as a source of natural products in a controlled environment.
Designing video profile fashion program Malang State University using adobe premiere
Authors: Aini N , Hidayati N , Rahayu S E P
Published: June 2020

This research aims to make a video profile of Fashion Program in Malang state university. Whereas for a Program it must have a video profile, especially in digital era, it is necessary to make a video profile of the Fashion Program that serves as a very effective means of promotion to the public or others. In this research use Adobe Premiere CC 2019 and Adobe Photoshop CS6 software, so as to create an attractive video profile display. The research method divided into 3 stages, namely pre-production, production, and post-production. The results of the expert validation test, the video profile of Fashion Program was declared very feasible. Some suggestions given by experts, improvements were made, so as to create a video profile that was ready to be used as a promotional tool for Fashion Programs in Malang State University.
E-commerce implementation in supporting business services strategy (case study at petshop gifaro evidence)
Authors: Purba J T , Hery  , Widjaja A E
Published: June 2020

The aim of this paper is introduced the importance of information technology for all petshop business units. Givaro Petshop is a business to provides products for the needs of pet supplies and pet care services. Recently the Givaro Petshop still managed product inventory manually. To improve the business, Givaro Petshop need an e-commerce website that can improve the effectiveness of business processes.The development of the Givaro Petshop e-commerce website uses Systems Development Life Cycle (SDLC) with the Rapid Application Development Prototyping methodology. The results of this study are an e-commerce website that can be used to record inventory of products owned, record sales transactions, receive orders for animal care services, manage various reports needed and provide information to the general public.
Solid state organic photovoltaic devices using spirulina sp thylakoid membrane films as active material
Authors: Hidayah Q , Kusuma D Y , Aji O R , Izziyah A N , Purnama B
Published: June 2020

Efficient light-to-energy conversion in Photosynthetis proceeds with quantum efficiency near unity. However, solar cell devices which incorporates chlorophyll such as DSSC generally requires elaborate fabrication process and complex device structure with liquid electrolyte. In this work, a solid state organic solar cell device is presented. The device employs simple structure of ITO/Thylakoid membrane/Al layer in a solid state structure without require liquid electrolyte. As the active materials, Thylakoid membrane layer contains the whole photosynthetic pigment-protein complexes including Photosystem I and Photosystem II. Preliminary characterization of the solid state organic photovoltaic devices exhibits modest ISC of 0.44 μA, VOC of 0.17 V, and Fill Factor of 0.250 when illuminated under the 1 mW/cm2 incandescent radiation power. Plot of (αhv)2 against the (hv) for tyakoid membrane active materials reveals major optical band-gap values of 4.0–4.1 eV which corresponds to the absorbtion from the PS I and PS II light harvesting complexes. This encouraging result implies that incorporating the whole photosynthetic pigment-protein complex can enhance the performance of organic solar cell significantly.
An Analysis of the utilization of Gamal Plant (Gliricidia sepium) as a shade for coffee plants
Authors: Khusnul K , Suratno  , Prihatin J , Sudarti
Published: June 2020

Indonesia is the largest coffee exporter in the world, which is in the fourth position after Brazil, Vietnam and Colombia. However, the productivity of coffee produced from year to year tends to decrease and not optimal. This happens because of many factors, one of which is the type of shade plants used. Inappropriate shade plants affect the growth and productivity of coffee plants. The purpose of this research was to analyze the utilization of Gamal plant (Gliricidia sepium) as a shade for coffee plants. The respondents of this research were 35 coffee farmers in Jember and Banyuwangi regencies. The research variables measured included the types of coffee shade plants, reasons for using shade plants and farmers' knowledge about Gamal plant as a shade for coffee plants. The data collection was carried out using survey, interview and questionnaire. The data collection was done directly with the primary source. The results of this research informed that the shade plants used by coffee farmers were varied, such as banana, lamtoro, coconut tree, Gamal, avocado and sengon trees. Most of the coffee farmers used bananas by 86%, avocados by 65%, and wood by 46% as a shade. They chose the plants because they were easier to maintain, cheap seeds and produced fruit and woods which could be sold. Based on the literature, the most effective shade plants for coffee plants were Gamal plants. However, Gamal plant (Gliricidia sepium) is still not widely used by coffee farmers because the seeds are too expensive and it does not produce fruit that can be sold. The conclusion of this research was that most of the coffee farmers were still unaware and did not use Gamal as a shade plants.
An analysis of innovation on the utilization of cascara by coffee farmers
Authors: Komaria N , Suratno  , Prihatin J , Sudarti
Published: June 2020

The process of coffee production yields a lot of waste. Based on the observation, there was no innovation in the use of cascara to have high economic value, some amount of abundant cascara is used by the farmers as cattle feed and the rest is sold. The aim of this research was to analyze the level of innovation in cascara utilization by the coffee farmers. The variables of this research were the type of innovation used by the cascara community and the analysis of the economic value that has been obtained. The methods used were survey, interview, and questionnaire. The respondents of this study consisted of 26 coffee farmers in Jember regency. The results showed that the farmers who used cascara as fertilizer were 3.9%, cattle feed by 7.7%, used cascara tea of 3.9%, sold cascara by 65.3% and disposed it as much 19.2%. Based on the economic value, the use of cascara which has the lowest value is disposed it while the higher one is sold it, use it as cattle feed, fertilizer and cascara tea. Education for farmers is needed to make cascara benefits well in producing innovative and environmentally friendly products.
H-Infnitiy for world crude oil price estimation
Authors: Anshori M Y , Herlambang T , Karya D F , Rahmalia D , Inawati P A
Published: June 2020

In international or globalised trading, commodity trading does not only depend on the commodity, but also the role that companies have in commodity production and distribution. One step made by oil companies clearly determine the world oil prices associated with oil deposits (inventory) and drilling. The strategy they adopt in production will also be have strong effects on the world oil price trends. To observe the fluctuation of the world oil prices, an effort shall be made by estimating the world crude oil prices so that entrepreneurs can predict when the world oil prices fall or rise and determine policies in the production and use of oil. This study was to aplly method of the world crude oil price estimation, namely H-Infinity to determine the right decision the oil entrepreneurs shall make regarding the world crude oil. The simulation results showed that the application the H-Infinity method had an accuracy of around 97-98%.
Prediction of Indonesian financial crisis using Markov regime switching autoregressive conditional heteroscedasticity models based on bank deposits and lending/deposit interest rate indicators
Authors: Maulana A , Sugiyanto  , Slamet I
Published: June 2020

The financial crisis that occurred in middle of 1997 made Indonesia to become one of the countries which had the worst and the longest affected in term of its rate of recovery. This event made us aware of the importance of creating an early warning system for the financial crisis. The crisis occurred due to several macroeconomic indicators experiencing very high fluctuation and changes in the structure of the condition (regime). The combination of volatility and Markov regime switching models is a type of model that can explain the fluctuation and changes in such condition. The indicators of bank deposit and lending/deposit interest rate in January 1990 to June 2019 were used to construct the combined model. The results of this research showed that the MRS-ARCH(2,1) model for the bank deposit and lending/deposit interest rate indicators can explain the conditions of the financial crisis that occurred. The predicted value of the MRS-ARCH(2,1) model shows that from July 2019 to June 2020 there were no signs of a financial crisis in Indonesia.
Early detection models of currency crises in Indonesia based on inflation and interest rates indicators
Authors: Amri I F , Chamidah N , Sugiyanto
Published: June 2020

The global crisis that occurred in the middle of 1997 showed that the financial crisis had a huge impact on the Indonesian economy. The crisis happened because of several macroeconomic indicators experienced very high fluctuations that were followed by regime changes. The combination of the Markov regime-switching and volatility models are very suitable to explain high fluctuations and regime changes. The inflation and the interest rates indicators, it was obtained that the best model of those indicators was MRS-AR (2,1) and MRS-GARCH (2,2,0), respectively. The MRS-AR (2,1) model can capture crises from August 1997 to December 1998, while the MRS-GARCH (2,2,0) model can capture crises from January to December 1998. The smoothed probability prediction values of the two models, it could be concluded that Indonesia did not experience a currency crisis in 2019.
Mathematical modelling of two layer shallow water flow with incline and uneven bottom
Authors: Lina I R , Habibah U , Kusumawinahyu W M
Published: June 2020

This study aims to construct mathematical model of two layer shallow water flow based on physical phenomenon. The proposed model is with attention to incline and uneven bottom, usually is chosen as function of space b(x). The result is the governing equation of each layer consist of mass continuity and momentum equations. The layers of the model are determined by the density of the fluid. The first layer is water exposed to sunshine which the temperature is higher than the second layer. The difference of density between the first and the second layer results the difference of gravity force which in the second layer we use reduced gravity force (gravity force decreases due to density ratio).