La Agusu - Academia.edu (original) (raw)

Papers by La Agusu

Research paper thumbnail of 300MHz及び600MHz DNP-NMR用ジャイロトロンの開発 (平成20年度 福井大学遠赤外領域開発研究センター 研究成果報告書) -- (高出力遠赤外光源--ジャイロトロンの開発)

遠赤外領域開発研究 : 福井大学遠赤外領域開発研究センター研究成果報告書, 2008

Research paper thumbnail of Development of a short pulse, high power, large orbit gyrotron using a high voltage pulse supply ETIGO-IV

A high power gyrotron using pulsed power generator ETIGO-IV is being developed. The typical outpu... more A high power gyrotron using pulsed power generator ETIGO-IV is being developed. The typical output waveform to a matched load of ETIGO-IV is 400 kV in peak voltage, 13 kA in peak current and 120 ns in pulse length. The combination of high energy electron beam with such a power supply and a high magnetic field opens the possibility of submillimeter wave generation with an output power above 1 MW to a large orbit gyrotron.

Research paper thumbnail of Electron gun for powerful large orbit gyrotron

Research paper thumbnail of Powerful large orbit gyrotron of submillimeter wavelength range

Infrared and Millimeter Waves, Conference Digest of the 2004 Joint 29th International Conference on 2004 and 12th International Conference on Terahertz Electronics, 2004.

Preliminary design of cavity for high power submillimeter large orbit gyrotron has been described... more Preliminary design of cavity for high power submillimeter large orbit gyrotron has been described. Time-dependent, multi-mode calculation gives us the possibility to achieve output power of up to 1.5 MW with a frequency 420.8 GHz at third harmonic. The most important advantages of LOG are possibility of selective excitation of high harmonic number. However, due to low efficiency of this devices (typically a few percents), high output power needs powerful electron beams.

Research paper thumbnail of Towards DNP enhanced solid-state NMR at 14.1 T

ABSTRACT A solid-state Dynamic Nuclear Polarisation (DNP) enhanced NMR spectrometer designed to o... more ABSTRACT A solid-state Dynamic Nuclear Polarisation (DNP) enhanced NMR spectrometer designed to operate at 600 MHz 1H NMR frequency is described. It uses an FU CW VII gyrotron as the microwave source producing up to ~ 130 W of fundamental power at 187 GHz in the TE13 mode and ~ 30 W of second harmonic at 395 GHz in the TE16 mode corresponding to 287 MHz and 600 MHz 1H NMR frequencies respectively. The output from the gyrotron is converted to a quasi-optic Gaussian beam using a Vlasov antenna and transmitted to the NMR probe via an optical bench with beam splitters for monitoring and adjusting the microwave power, a ferrite rotator for stopping reflected power, and a Martin-Puplett interferometer for adjusting the polarisation. The output from the bench is transmitted via corrugated waveguide (for low loss) into the Magic Angle Spinning NMR probe. The probe design allows it to be used at 90 K (needed for DNP to be effective) in triple channel HXY mode at 14.1 T and double channel HX mode at 287 MHz 1H NMR. Since it is essential to irradiate the electron spin system at its resonant frequency the NMR magnet has a superconducting sweep coil and a persistent-mode switch on the main coil to reduce He boil off.

Research paper thumbnail of Pelatihan Pemurnian Minyak Nilam Hasil Suling Konvensional Masyarakat Di Desa Awalo Kecamatan Benua Konawe Selatan Melalui Teknik Filtrasi Sederhana

Jurnal Pengabdian Masyarakat Ilmu Terapan (JPMIT), 2021

Penyulingan minyak nilam di desa Awalo masih menggunakan teknik penyulingan konvensional sehingga... more Penyulingan minyak nilam di desa Awalo masih menggunakan teknik penyulingan konvensional sehingga minyak nilam (patchouli oil) yang dihasilkan dari penyulingan tersebut masih berwarna cokelat tua yang mengindikasikan bahwa minyak nilam yang dihasilkan dari penyulingan tersebut belum memenuhi baku mutu minyak nilam sesuai SNI 06-2385-2006. Hasil penelitian menunjukkan bahwa selain patchouli alcohol yang merupakan komponen penyusun utama minyak nilam, kontaminan seperti ion logam Fe juga dijumpai dalam minyak nilam. Beberapa peneliti melaporkan bahwa sumber utama ion logam tersebut berasal dari wadah penyulingan konvensional pada saat proses penyulingan. Kehadiran ion logam seperti Fe dalam minyak nilam akan menyebabkan pembentukan ion kelat yang dapat mengakibatkan warna minyak nilam menjadi cokelat tua. Solusi dari masalah ini dapat dilakukan melalui teknik filtrasi (penyaringan) sederhana menggunakan prinsip adsorpsi berbasis silika, arang aktif dan batuan mangan alam. Minyak nilam...

Research paper thumbnail of Pelatihan Pemanfaatan Limbah Soft Plastik Sebagai Material Pengisi Pada Pembuatan Batu Bata Ringan Bagi Pengusaha Batu Bata DI Desa Boro-Boro Lameuru, Kecamatan Ranomeeto, Kabupaten Konawe Selatan

Jurnal Pengabdian Masyarakat Ilmu Terapan (JPMIT), 2020

Pencemaran lingkungan yang disebabkan oleh sampah terutama soft plastik adalah hal yang tidak bis... more Pencemaran lingkungan yang disebabkan oleh sampah terutama soft plastik adalah hal yang tidak bisa dihindari lagi saat ini. Metode daur ulang, pemakaian kembali dan pengurangan adalah beberapa metode yang bisa dilakukan untuk mengurangi limbah soft plastik yang terus bertambah. Soft plastik tersebut dapat dikurangi melalui pembuatan batu bata ringan, di mana soft plastik dijadikan sebagai material pengisi untuk mengurangi penggunaan tanah liat atau lempung yang merupakan bahan baku pembuatan batu bata. Pemanfaatan soft plastik dalam industri batu bata ringan akan mempengaruhi produksi batu bata ringan tersebut, baik dalam aspek kuantitas maupun kualitas. Program PKMI akan mengajarkan kepada masyarakat Desa Boro-Boro Lameuru melalui bimbingan teknis dan dan praktek lapangan tentang pemanfaatan soft plastik untuk membuat batu bata ringan. Solusi ini dipakai untuk mengurangi jumlah sampah soft plastik yang ada Desa Boro-Boro Lamuru, bahkan soft plastik yang ada di Tempat Pembuangan Akh...

Research paper thumbnail of 20aZH-3 周波数可変Gyrotron FU CW IVの開発(20aZH プラズマ科学(ジャイロトロン),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Research paper thumbnail of Penyarian Konstituen Organik Daging Buah Gaharu (Aquilaria malaccensis Lamk.) dengan Metode Maserasi Berbantu Microwave dan Uji Aktivitas Sebagai Antioksidan

KOVALEN: Jurnal Riset Kimia

This study was conducted to determine the organic constituents and to test the antioxidant activi... more This study was conducted to determine the organic constituents and to test the antioxidant activity and toxicity of gaharu fruit pulp extract (Aquilaria malaccensis Lamk.). Gaharu fruit pulp extract was obtained through Microwave Assisted Extraction (MAE) method and then extracted with a solvent with different polarity, namely ethyl acetate and n-hexane. The obtained yield of ethyl acetate extract of the gaharu fruit pulp was 40.827% w/v, whereas 0% w/v in n-hexane extract, therefore, no further test for n-hexane extract, so that the n-hexane extract was not tested for the next stage. The results of the organic constituents of the ethyl acetate extract of gaharu fruit pulp showed flavonoids, saponins, glycosides, phenols and tannins. Antioxidant activity testing was carried out using the DPPH method with vitamin C as a positive control. The results of the antioxidant activity test showed that IC50 of ethyl acetate extract of gaharu fruit pulp and vitamin C were 143.789ppm and 13.797...

Research paper thumbnail of Development of a THz CW gyrotron FU CW III

Research paper thumbnail of 28aGY-12 20T超伝導マグネットを用いたテラヘルツジャイロトロンの開発VI(28aGY プラズマ科学(ビーム応用・プラズマ応用),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2011

Research paper thumbnail of 30pXE-12 DNP-NMRのためのジャイロトロンFU CW IIAの開発II(30pXE プラズマ科学(電磁波源・ジャイロトロン),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2009

Research paper thumbnail of 20aZH-1 Development of Tera Hertz Gyrotron Using 20T Superconducting Magnet III

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2008

Research paper thumbnail of 25aXG-9 小型パルスパワー装置を用いた高出力・高周波ジャイロトロンの開発(プラズマ科学(ジャイロトロン),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2005

Research paper thumbnail of 22aTB-1 Design of a THz Gyrotron(Gyrotron FU CW III) : Using a 20 T Superconducting Magnet

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2007

Research paper thumbnail of 15aQA-2 400 keV 電子ビームを用いた高出力 LOG の開発 II(プラズマ科学 : 電磁波発生・応用, 領域 2)

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2004

Research paper thumbnail of Application of Cauchy-Schwarz inequality method for resolving constrained optimization problems at classroom with formal pre-operational phase of thinking

Journal of Physics: Conference Series, 2021

The optimization problem is a mathematical problem that is introduced at the junior high school l... more The optimization problem is a mathematical problem that is introduced at the junior high school level. Material related to optimization has even been introduced for elementary school levels in students with a level of concrete operations, especially for students who are prepared to take part in the Math Olympiad. The problem arises here, is that complicated methods for finding solutions to optimization problems, such as the simplex method, ordinary differential equations, partial differential equations, and the Lagrange multiplier were only introduced in high school or in college. To bridge this we need a special method that is easily understood by students participating in the pre-Olympic who are at the level of formal preoperative cognition, one of these methods is called the Cauchy-Schwarz inequality method. The Cauchy-Schwarz inequality is a powerful tool for finding the maximum and minimum solutions for a target equation with one or two constraint equations. The interesting thi...

Research paper thumbnail of Experimental results of high-power, short-pulse, large orbit gyrotron using a pulse power generator "ETIGO-IV

2006 Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Teraherz Electronics, 2006

ABSTRACT An ultra-high power gyrotron is being developed in millimeter and submillimeter waveleng... more ABSTRACT An ultra-high power gyrotron is being developed in millimeter and submillimeter wavelength region. It is a large orbit gyrotron (LOG) with an intense relativistic electron beam (IREB). A pulsed power generator "ETIGO-IV" is used for IREB generation. The prototype LOG with a pulse magnet has been constructed. The first operation test was successfully carried out in millimeter wavelength region. The experimental results are presented.

Research paper thumbnail of Production and characterization of briquette from the activated charcoal of corncob

Journal of Physics: Conference Series, 2019

Waste agricultural biomass (corn cobs) was carbonized in a metal kiln, 90cm in height and 60cm di... more Waste agricultural biomass (corn cobs) was carbonized in a metal kiln, 90cm in height and 60cm diameter. Four different briquette charcoal grades were produced using locally sourced tapioca starch as binder at concentrations of 6.0, 10.0, 14.0 and 19.0 % w/w. Characterization test was carried out for the charcoal briquettes. The fixed carbon content of the briquette grades is 72.776, 73.958, 78.794, 81.884% w/w respectively. Similarly, the ash content for the briquette grades is 21.38, 20.70, 14.24 and 11.49 % w/w respectively. The bulk density is 425.6, 425.7, 425.0 and 358.3 kg/m 3 respectively and the moisture content is 5.88, 5.34, 6.99 and 6.63 % w/w respectively. The properties of the produced briquette charcoal were compared with that of sugarcane bagasse and wood charcoal. The briquette charcoal was found to be a better fuel when compared to both sugarcane bagasse and wood charcoal, having a highest fixed carbon content and highest bulk density. The corn cobs briquettes have lower moisture content compared to sugarcane bagasse however has higher moisture content than wood charcoal. In addition, the sugarcane bagasse and wood charcoal were found to have lower ash content (4.33 % and 9.80% respectively) compared to all the five charcoal grades produced. The briquette charcoal has a mean calorific value of 32.4 MJ/kg which is significantly higher than that of both bagasse at 23.4 MJ/kg and wood charcoal at 8.27MJ/kg.

Research paper thumbnail of Synthesize of rGO from coal (sub-bituminous) as a counter-electrode on dye-sensitized solar cells

Journal of Physics: Conference Series, 2021

In the quest for a replacement for platinum as catalytic material in DSSC’s counter electrode (CE... more In the quest for a replacement for platinum as catalytic material in DSSC’s counter electrode (CE), this research aims to extract reduced graphene oxide (rGO) from coal. The coal used was a sub-bituminous type originated from Kolaka Timur, which extracted to rGO with modified Hummer methods. The resulting rGO was characterized by Energy Dispersive X-Ray Spectroscopy (EDS), FTIR, XRD, and LCR meter, to investigate the atomic composition, chemical bonds, crystal structure, and conductivity. For CE fabrication, rGO was mixed with ethyl cellulose (EC) and dissolved in terpineol with a ratio of 100:10, 100:20, 100:50, 100:70, and 100:100 in weight. The structure of the fabricated solar cell was FTO/TiO2/Dye/Electrolyte/rGO/FTO. From the EDS result, we identified the elements of C and O that was the main constituent for rGO, with the highest C/O ratio was 0.81. From FTIR spectra, it was found that the rGO still contain impurities originated from quartz, kaolinite and illite mineral. From ...

Research paper thumbnail of 300MHz及び600MHz DNP-NMR用ジャイロトロンの開発 (平成20年度 福井大学遠赤外領域開発研究センター 研究成果報告書) -- (高出力遠赤外光源--ジャイロトロンの開発)

遠赤外領域開発研究 : 福井大学遠赤外領域開発研究センター研究成果報告書, 2008

Research paper thumbnail of Development of a short pulse, high power, large orbit gyrotron using a high voltage pulse supply ETIGO-IV

A high power gyrotron using pulsed power generator ETIGO-IV is being developed. The typical outpu... more A high power gyrotron using pulsed power generator ETIGO-IV is being developed. The typical output waveform to a matched load of ETIGO-IV is 400 kV in peak voltage, 13 kA in peak current and 120 ns in pulse length. The combination of high energy electron beam with such a power supply and a high magnetic field opens the possibility of submillimeter wave generation with an output power above 1 MW to a large orbit gyrotron.

Research paper thumbnail of Electron gun for powerful large orbit gyrotron

Research paper thumbnail of Powerful large orbit gyrotron of submillimeter wavelength range

Infrared and Millimeter Waves, Conference Digest of the 2004 Joint 29th International Conference on 2004 and 12th International Conference on Terahertz Electronics, 2004.

Preliminary design of cavity for high power submillimeter large orbit gyrotron has been described... more Preliminary design of cavity for high power submillimeter large orbit gyrotron has been described. Time-dependent, multi-mode calculation gives us the possibility to achieve output power of up to 1.5 MW with a frequency 420.8 GHz at third harmonic. The most important advantages of LOG are possibility of selective excitation of high harmonic number. However, due to low efficiency of this devices (typically a few percents), high output power needs powerful electron beams.

Research paper thumbnail of Towards DNP enhanced solid-state NMR at 14.1 T

ABSTRACT A solid-state Dynamic Nuclear Polarisation (DNP) enhanced NMR spectrometer designed to o... more ABSTRACT A solid-state Dynamic Nuclear Polarisation (DNP) enhanced NMR spectrometer designed to operate at 600 MHz 1H NMR frequency is described. It uses an FU CW VII gyrotron as the microwave source producing up to ~ 130 W of fundamental power at 187 GHz in the TE13 mode and ~ 30 W of second harmonic at 395 GHz in the TE16 mode corresponding to 287 MHz and 600 MHz 1H NMR frequencies respectively. The output from the gyrotron is converted to a quasi-optic Gaussian beam using a Vlasov antenna and transmitted to the NMR probe via an optical bench with beam splitters for monitoring and adjusting the microwave power, a ferrite rotator for stopping reflected power, and a Martin-Puplett interferometer for adjusting the polarisation. The output from the bench is transmitted via corrugated waveguide (for low loss) into the Magic Angle Spinning NMR probe. The probe design allows it to be used at 90 K (needed for DNP to be effective) in triple channel HXY mode at 14.1 T and double channel HX mode at 287 MHz 1H NMR. Since it is essential to irradiate the electron spin system at its resonant frequency the NMR magnet has a superconducting sweep coil and a persistent-mode switch on the main coil to reduce He boil off.

Research paper thumbnail of Pelatihan Pemurnian Minyak Nilam Hasil Suling Konvensional Masyarakat Di Desa Awalo Kecamatan Benua Konawe Selatan Melalui Teknik Filtrasi Sederhana

Jurnal Pengabdian Masyarakat Ilmu Terapan (JPMIT), 2021

Penyulingan minyak nilam di desa Awalo masih menggunakan teknik penyulingan konvensional sehingga... more Penyulingan minyak nilam di desa Awalo masih menggunakan teknik penyulingan konvensional sehingga minyak nilam (patchouli oil) yang dihasilkan dari penyulingan tersebut masih berwarna cokelat tua yang mengindikasikan bahwa minyak nilam yang dihasilkan dari penyulingan tersebut belum memenuhi baku mutu minyak nilam sesuai SNI 06-2385-2006. Hasil penelitian menunjukkan bahwa selain patchouli alcohol yang merupakan komponen penyusun utama minyak nilam, kontaminan seperti ion logam Fe juga dijumpai dalam minyak nilam. Beberapa peneliti melaporkan bahwa sumber utama ion logam tersebut berasal dari wadah penyulingan konvensional pada saat proses penyulingan. Kehadiran ion logam seperti Fe dalam minyak nilam akan menyebabkan pembentukan ion kelat yang dapat mengakibatkan warna minyak nilam menjadi cokelat tua. Solusi dari masalah ini dapat dilakukan melalui teknik filtrasi (penyaringan) sederhana menggunakan prinsip adsorpsi berbasis silika, arang aktif dan batuan mangan alam. Minyak nilam...

Research paper thumbnail of Pelatihan Pemanfaatan Limbah Soft Plastik Sebagai Material Pengisi Pada Pembuatan Batu Bata Ringan Bagi Pengusaha Batu Bata DI Desa Boro-Boro Lameuru, Kecamatan Ranomeeto, Kabupaten Konawe Selatan

Jurnal Pengabdian Masyarakat Ilmu Terapan (JPMIT), 2020

Pencemaran lingkungan yang disebabkan oleh sampah terutama soft plastik adalah hal yang tidak bis... more Pencemaran lingkungan yang disebabkan oleh sampah terutama soft plastik adalah hal yang tidak bisa dihindari lagi saat ini. Metode daur ulang, pemakaian kembali dan pengurangan adalah beberapa metode yang bisa dilakukan untuk mengurangi limbah soft plastik yang terus bertambah. Soft plastik tersebut dapat dikurangi melalui pembuatan batu bata ringan, di mana soft plastik dijadikan sebagai material pengisi untuk mengurangi penggunaan tanah liat atau lempung yang merupakan bahan baku pembuatan batu bata. Pemanfaatan soft plastik dalam industri batu bata ringan akan mempengaruhi produksi batu bata ringan tersebut, baik dalam aspek kuantitas maupun kualitas. Program PKMI akan mengajarkan kepada masyarakat Desa Boro-Boro Lameuru melalui bimbingan teknis dan dan praktek lapangan tentang pemanfaatan soft plastik untuk membuat batu bata ringan. Solusi ini dipakai untuk mengurangi jumlah sampah soft plastik yang ada Desa Boro-Boro Lamuru, bahkan soft plastik yang ada di Tempat Pembuangan Akh...

Research paper thumbnail of 20aZH-3 周波数可変Gyrotron FU CW IVの開発(20aZH プラズマ科学(ジャイロトロン),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Research paper thumbnail of Penyarian Konstituen Organik Daging Buah Gaharu (Aquilaria malaccensis Lamk.) dengan Metode Maserasi Berbantu Microwave dan Uji Aktivitas Sebagai Antioksidan

KOVALEN: Jurnal Riset Kimia

This study was conducted to determine the organic constituents and to test the antioxidant activi... more This study was conducted to determine the organic constituents and to test the antioxidant activity and toxicity of gaharu fruit pulp extract (Aquilaria malaccensis Lamk.). Gaharu fruit pulp extract was obtained through Microwave Assisted Extraction (MAE) method and then extracted with a solvent with different polarity, namely ethyl acetate and n-hexane. The obtained yield of ethyl acetate extract of the gaharu fruit pulp was 40.827% w/v, whereas 0% w/v in n-hexane extract, therefore, no further test for n-hexane extract, so that the n-hexane extract was not tested for the next stage. The results of the organic constituents of the ethyl acetate extract of gaharu fruit pulp showed flavonoids, saponins, glycosides, phenols and tannins. Antioxidant activity testing was carried out using the DPPH method with vitamin C as a positive control. The results of the antioxidant activity test showed that IC50 of ethyl acetate extract of gaharu fruit pulp and vitamin C were 143.789ppm and 13.797...

Research paper thumbnail of Development of a THz CW gyrotron FU CW III

Research paper thumbnail of 28aGY-12 20T超伝導マグネットを用いたテラヘルツジャイロトロンの開発VI(28aGY プラズマ科学(ビーム応用・プラズマ応用),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2011

Research paper thumbnail of 30pXE-12 DNP-NMRのためのジャイロトロンFU CW IIAの開発II(30pXE プラズマ科学(電磁波源・ジャイロトロン),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2009

Research paper thumbnail of 20aZH-1 Development of Tera Hertz Gyrotron Using 20T Superconducting Magnet III

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2008

Research paper thumbnail of 25aXG-9 小型パルスパワー装置を用いた高出力・高周波ジャイロトロンの開発(プラズマ科学(ジャイロトロン),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2005

Research paper thumbnail of 22aTB-1 Design of a THz Gyrotron(Gyrotron FU CW III) : Using a 20 T Superconducting Magnet

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2007

Research paper thumbnail of 15aQA-2 400 keV 電子ビームを用いた高出力 LOG の開発 II(プラズマ科学 : 電磁波発生・応用, 領域 2)

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2004

Research paper thumbnail of Application of Cauchy-Schwarz inequality method for resolving constrained optimization problems at classroom with formal pre-operational phase of thinking

Journal of Physics: Conference Series, 2021

The optimization problem is a mathematical problem that is introduced at the junior high school l... more The optimization problem is a mathematical problem that is introduced at the junior high school level. Material related to optimization has even been introduced for elementary school levels in students with a level of concrete operations, especially for students who are prepared to take part in the Math Olympiad. The problem arises here, is that complicated methods for finding solutions to optimization problems, such as the simplex method, ordinary differential equations, partial differential equations, and the Lagrange multiplier were only introduced in high school or in college. To bridge this we need a special method that is easily understood by students participating in the pre-Olympic who are at the level of formal preoperative cognition, one of these methods is called the Cauchy-Schwarz inequality method. The Cauchy-Schwarz inequality is a powerful tool for finding the maximum and minimum solutions for a target equation with one or two constraint equations. The interesting thi...

Research paper thumbnail of Experimental results of high-power, short-pulse, large orbit gyrotron using a pulse power generator "ETIGO-IV

2006 Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Teraherz Electronics, 2006

ABSTRACT An ultra-high power gyrotron is being developed in millimeter and submillimeter waveleng... more ABSTRACT An ultra-high power gyrotron is being developed in millimeter and submillimeter wavelength region. It is a large orbit gyrotron (LOG) with an intense relativistic electron beam (IREB). A pulsed power generator "ETIGO-IV" is used for IREB generation. The prototype LOG with a pulse magnet has been constructed. The first operation test was successfully carried out in millimeter wavelength region. The experimental results are presented.

Research paper thumbnail of Production and characterization of briquette from the activated charcoal of corncob

Journal of Physics: Conference Series, 2019

Waste agricultural biomass (corn cobs) was carbonized in a metal kiln, 90cm in height and 60cm di... more Waste agricultural biomass (corn cobs) was carbonized in a metal kiln, 90cm in height and 60cm diameter. Four different briquette charcoal grades were produced using locally sourced tapioca starch as binder at concentrations of 6.0, 10.0, 14.0 and 19.0 % w/w. Characterization test was carried out for the charcoal briquettes. The fixed carbon content of the briquette grades is 72.776, 73.958, 78.794, 81.884% w/w respectively. Similarly, the ash content for the briquette grades is 21.38, 20.70, 14.24 and 11.49 % w/w respectively. The bulk density is 425.6, 425.7, 425.0 and 358.3 kg/m 3 respectively and the moisture content is 5.88, 5.34, 6.99 and 6.63 % w/w respectively. The properties of the produced briquette charcoal were compared with that of sugarcane bagasse and wood charcoal. The briquette charcoal was found to be a better fuel when compared to both sugarcane bagasse and wood charcoal, having a highest fixed carbon content and highest bulk density. The corn cobs briquettes have lower moisture content compared to sugarcane bagasse however has higher moisture content than wood charcoal. In addition, the sugarcane bagasse and wood charcoal were found to have lower ash content (4.33 % and 9.80% respectively) compared to all the five charcoal grades produced. The briquette charcoal has a mean calorific value of 32.4 MJ/kg which is significantly higher than that of both bagasse at 23.4 MJ/kg and wood charcoal at 8.27MJ/kg.

Research paper thumbnail of Synthesize of rGO from coal (sub-bituminous) as a counter-electrode on dye-sensitized solar cells

Journal of Physics: Conference Series, 2021

In the quest for a replacement for platinum as catalytic material in DSSC’s counter electrode (CE... more In the quest for a replacement for platinum as catalytic material in DSSC’s counter electrode (CE), this research aims to extract reduced graphene oxide (rGO) from coal. The coal used was a sub-bituminous type originated from Kolaka Timur, which extracted to rGO with modified Hummer methods. The resulting rGO was characterized by Energy Dispersive X-Ray Spectroscopy (EDS), FTIR, XRD, and LCR meter, to investigate the atomic composition, chemical bonds, crystal structure, and conductivity. For CE fabrication, rGO was mixed with ethyl cellulose (EC) and dissolved in terpineol with a ratio of 100:10, 100:20, 100:50, 100:70, and 100:100 in weight. The structure of the fabricated solar cell was FTO/TiO2/Dye/Electrolyte/rGO/FTO. From the EDS result, we identified the elements of C and O that was the main constituent for rGO, with the highest C/O ratio was 0.81. From FTIR spectra, it was found that the rGO still contain impurities originated from quartz, kaolinite and illite mineral. From ...