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"In spite of abundant experimental evidences supporting the viability of the laser induced shock wave plasma model for the explanation of the important features ofthe plasma and the associated spectroscopic characteristics, a controversy on the atomic excitation mechanism in the plasma has remained to be completely resolved. In this study the contributions of the shock wave model and two other most popular models, the electron-ion recombination model and thc electron collision model were thoroughly investigated. For that purpose, a special technique has been developed for the direct detection of the charge current in conjunction with plasma emission measurement dining the laser plasma generation and expansion. The current detection was performed by placing a partially transmitting metal mesh electrode at a distance in front of the sample surface with the sample target sewing as the counter electrode. The electric Held between the mesh and sample surface was set up and varied by applying a variable DC voltage (0-400 Volt) between them. The laser plasma was generated by a YAG laser (64 ml, 8 ns) tightly focused on a Cu target through the mesh electrode in low-pressure surrounding gas. It was found that the charge current time profiles obtained at various gas pressures invariably exhibit a lack of consistent correlation with the emission time profile of the plasma throughout most of the emission period. The result of this study has thus practically eliminated any significant roles ofthe electron-ion recombination and electron collision models in the excitation process. We are therefore led to conclude that the shock wave model proposed earlier is most plausible for the consistent explanation of the secondary plasma emission, while the other two models may have some contribution only at the very initial stage ofthe secondary plasma generation."

"ABSTRACTIn spite of abundant experimental evidences supporting the viability of the laserinduced shock wave plasma model for the explanation of the important features oftheplasma and the associated spectroscopic characteristics, a controversy on the atomicexcitation mechanism in the plasma has remained to be completely resolved. In thisstudy the contributions of the shock wave model and two other most popular models,the electron-ion recombination model and thc electron collision model werethoroughly investigated. For that purpose, a special technique has been developed forthe direct detection of the charge current in conjunction with plasma emissionmeasurement dining the laser plasma generation and expansion. The current detectionwas performed by placing a partially transmitting metal mesh electrode at a distancein front of the sample surface with the sample target sewing as the counter electrode.The electric Held between the mesh and sample surface was set up and varied byapplying a variable DC voltage (0-400 Volt) between them. The laser plasma wasgenerated by a YAG laser (64 ml, 8 ns) tightly focused on a Cu target through themesh electrode in low-pressure surrounding gas. It was found that the charge currenttime profiles obtained at various gas pressures invariably exhibit a lack of consistentcorrelation with the emission time profile of the plasma throughout most of theemission period. The result of this study has thus practically eliminated anysignificant roles ofthe electron-ion recombination and electron collision models in theexcitation process. We are therefore led to conclude that the shock wave modelproposed earlier is most plausible for the consistent explanation of the secondaryplasma emission, while the other two models may have some contribution only at thevery initial stage ofthe secondary plasma generation.Key words: charge current, shock wave, electron-ion recombination and electroncollision.Praiseci is to the Lord for He is my reason in everything I do.This manuscript is never be done without the guidance by Pro£ Tjia May On, towhom I am extremely grateful. He also provided the support without which this thesiswould not possible. He is more than just a teacher for me for his words have deeplytouched me. Moreover, he also introduced me that knowledge is something we shouldshare among others and to improve the education in my country.I am also indebted to Prof. Kiichiro Kagawa at the Fukui University for providingthe atmosphere and the physical resources to make thesis writing in these times of fastpaced research. I am also thankful for the opportunity which is given to me to joinresearch together with him in his laboratory in Japan.Extra special thanks go to Dr. Hendrik Kurniawan for providing me withencouragement and support for this project. He is the first one who encouraged me totake Doctor Cotuse Program which seemed impossible at the beginning. Hiscompanion during research at Applied Spectroscopy Laboratory at University ofIndonesia is a leading experience in research for me.I am particularly grateful to the excellent team of referees who provided criticalcomments on this thesis. Their feedback was a great benefit to me.I gratefully acknowledge all my colleagues: Rinda Hedwig, Mangasi A.Marpaung, Hery Suyanto, MM. Suliyanti, Wahyu S. Budi, and Emon in AppliedSpectroscopy Laboratory at University of Indonesia, for their assistance and supportduring my study.My never-ending thanks to my beloved family, especially to my parents whoexhibited thoughtful patience over extended periods of time when I seemed to beinvisible. Thanks also to Loviana who helped me in all situations which I no longercan resist by myselflFinally, I apologize to all those who helped that I did not acknowledge specifically.I know there were many and greatly appreciate your assistance.August, 2002Author"

"A comprehensive study has been made on the dynamical process-taking place in the laser-plasma generation induced by a TEA CO2 laser bombardment on metal target and non-metal target from low to high pressures surrounding gas. In the case of metal target, pure zinc plate was used as a target and bombarded with 400-mJ-laser pulse energy. Dynamical characterization of plasma expansion and excitation were examined in detail both for target atomic emission (Zn I 481.0 nm) and gas atomic emission (He 1 587.6 nm) by using a unique time-resolved spatial distribution measurement and conventional emission spectroscopic detection method. The results showed that the plasma expands and develops with time. The mechanism of plasma generation can be classified into three cases depending on .the surrounding gas pressures; target shock wave plasma in the pressure range between 2 Ton and 20 Ton, coupling shock wave plasma in the pressure range between 50 Torr and 200 Torr and gas break down shock wave plasma in the pressure range between 200 Ton and I atm. In all cases in the laser-plasma generation under TEA CO2 laser bombardment on metal target, shock wave process always plays important role for exciting the target atoms and gas molecules.In the case of non-metal target, a museum glass was used as a target and bombarded with a 400 nd laser pulse energy. By using the conventional emission spectroscopic detection method, namely temporally and spatially integrated and time-resolved spatially integrated of plasma emission, it was shown that the plasma mainly consists of target atomic emission. Only weak gas atomic emission intensity could be observed even at I atm of surrounding gas pressure. These results indicate that the gas breakdown is not a major process responsible to the plasma formation even at high pressure surrounding gas. Shock wave process was considered as an important role in this plasma formation. By the use of shadowgraph technique to detect the density jump signal due to the shock wave front involving a He-Ne laser as a probe light, simultaneous detection of the shock wave front and the emission front was successfully implemented. The result showed that at the initial stages of plasma expansion shock wave front and emission front coincide and move together with time. At the later stages of plasma expansion the two fronts became separate with the emission front left behind the shock wave front. These results are completely coinciding with the shock wave plasma model. Unfortunately, in this experiment we succeed to detect the density jump signal only for high pressure surrounding gas, above 100 Torr. At the pressures lower than 100 Torr the density jump signal was very weak and it is difficult to distinguish with the noise including in the signal.The other important experimental results that support the shock wave plasma model were also obtained in this experiment, namely the coincidence of emission front regardless of their atomic weight and sub-target effect. By using lead glass as a sample, which contain Pb, Si, and Ca, it was confirmed that the emission front of the Pb I 450.8 nm, Si 1288.2 nm and Ca I 422.6 nm almost coincide regardless of their atomic weight. This result also supports the shock wave plasma model because, by the stagnation of the propelling atoms, the front position of the all atoms coincides regardless of its mass. In the case of sub-target effect, confirm that plasma could be produced even for soft target if sub-target is set behind the sample. In this case we use a quartz sample as a sub-target and a vinyl tape was attached to the quartz sample as a target. The TEA CO2 laser bombardment was used at 150 ml and at 1 atm of air. The main role of the subtarget is to produce a repulsion force for atom gushing with high speed. For shock wave, high speed is necessary condition to compress the gas.Coincidence of the movement of the shock wave front and the emission front in the initial stages of plasma expansion is a direct proof of the shock wave plasma model. By improving the detection technique of the density jump associated with the shock wave, the correlation between the shock wave front and the emission front was examined in detail. For this purpose rainbow interferometer system, which has higher sensitivity compared with the shadowgraph technique, was used to detect the density jump signal. We succeed to realize simultaneous detection of shock wave front and emission front from 3 Ton until 1 atm of air when a quartz sample is bombarded with a 600 nil TEA C02 laser. In all pressure that were examined, the shock wave front and the emission front always coincide and move together with time in the initial stages and separate at the later stages with emission front left behind the shock wave front. The coincidence of the shock wave front and emission front and move together with time at the initial stages of plasma expansion was also obtained by using ruby as a sample at 10 Torr and 100 Ton of air as well as with museum glass at the same laser pulse energy.Another important experimental result obtained in this experiment is that confirmation of the coincidence of the target atomic emission front and gas atomic emission front and density jump. This confirmation was obtained by examined a Quartz sample in 50 Ton of helium and a zinc sample in 100 Ton of helium. This result strongly supports the shock wave plasma model because, in ordinary shock tube experiment, gas emission takes place just behind the shock wave.From a practical point of view of direct microanalysis for spectrochemicaI application of alloy metal samples such as brass, selective vaporization effect was also studied. The results showed that even for Nd-YAG laser with short pulse duration (8 ns) and high power density (30 GWcm 2), selective vaporization take place to a certain extend. It was demonstrated in this experiment that selective vaporization is enhanced if the laser irradiation was repeated on the same spot of sample surface. Meanwhile it was also shown in this experiment that the effect of selective vaporization could be significantly suppressed by increasing the surrounding gas pressure from 2 Toff to around 50 Torr of air."

"ABSTRACTA comprehensive study has been made on the dynamical process taking place in the laser-plasma generation i.nduced by a TEA CO2 laser bombardment on metal target and non-metal target Eom low to high pressures surrounding gas. ln the case of metal target, pure zinc plate was used as a target and bombarded with 400 ml laser pulse energy. Dynamical characterization of plasma expansion and excitation were examined in detail both for target atomic emission (Zn I 481.0 nm) and gas atomic emission (He I 587.6 nm) by using an unique time-resolved spatial distribution measurement and conventionalemission spectroscopic detection method. The resultsshowed that the plasma expands and develops with time. The mechanism of plasma generation can be classified into three cases depending on the surrounding gas pressures; target shock wave plasma in the pnessure range between 2 Torr and 20 Torr, coupling shock wave plasma in the pressure range between S0 Torr and 200 Torr and gas ?break down shock wave plasma in the pressure range between 200 Torr and 1 atm. In all cases in the laser-plasma generation under TEA CO; laser bombardment on metal target, shock wave process-always plays important role forexciting the target atoms and gas molecules.ln the case of , non-metal target, a museum glass was used as a target and bombarded with a 400 mJ laser; pulse energy By using the conventional emission spectroscopic detection method, namely temporally and spatially integrated and time-resolved spatially integrated of plasma emission, it was shown that the plasma mainly consists of target atomic emission. Only weak gas atomic emission intensity could be observed even at 1 atm of surrounding gas pressure. These results indicate that the gas breakdown is not a major process responsible to the plasma formation even at high pressure surrounding gas. Shock wave process was considered as animportant role in this plasma formation. By the use of shadowgraph technique to detect the density jump signal due to the shock wave front involving a He-Ne laser as a probe light, simultaneous detection of the shock wave Bent and the emission iiont was successfully implemented. The result showed that at the initial stages of plasma expansion shock wave 'dont and emission front coincide and move together with time. At the later stages of plasma expansion the two fronts become separate with the emission front left behind the shock wave front. These results are completely coinciding with the shock wave plasma model. Unfortunately, in this experiment we succeed to detect the density jump signal only for high pressure surrounding gas, above 100 Torr. At the pressures lower than 100 Torr the density jump signal was very weak and it is diflicult to distinguish with the noise including in the signal.The other important experimental results that support the shock wave plasma model were also obtained in this experiment, namely the coincidence of emission iziont regardless of their atomic weight and sub-target effect. By using lead glass as a sample, which contain Pb, Si, and Ca, it was confirmed that the emission front of the Pb 1450.8 nm, Si I 288.2 nm and Ca I 422.6 nm almost coincide regardless of their atomic weight. This result also supports the shock wave plasma model because, by the stagnation of the propelling atoms, the front position of the all atoms coincides regardless of its mass. In the case of sub-target effect, we confirmed that plasmacould be produced even for sch target if sub-target is set behind the sample. In this case we use a sample as a sub-target and a vinyl tape was attached to the quartz sample as a target. The TEA CO2 laser bombardment was used at 150 mJ and at 1 atm of air. The main role ofthe subtarget is to produce a repulsion force for atom gushing with high speed. For shock wave, high speed is necessary condition to compress the gas.Coincidence of the movement of the shock wave iiiont and the emission front in the initial stages of plasma expansion is a direct proof of the shock wave plasma model. By improving the detection technique of the density jump associated with the shock wave, the correlation between the shockwave fiont and the emission front was examined in detail. For this purpose rainbow interferometer system, which has higher sensitivity compared with the shadowgraph technique, was used to detect the density jump signal. We succeed to realize simultaneous detection of shock wave front and emission front iiom 3 Torr until 1 atm of air when a quartz sample is bombarded with a 600 mJ TEA CO2 laser. In all pressure that were examined, the shock wave front and the emission front always coincide and move together with time in the initial stages and separate at the later stages with emission front left behind the shock wave tiont. The coincidence of the shock wave iiont and emission front and move together with time at the initial stages of plasma expansion was also obtained by using ruby as a sample at 10 Torr and 100 Torr of air as well as with museum glass at the same laser pulse energy."

"Baterai menjadi komponen kunci dalam sistem penyimpanan energi, maka dari itu sangat penting untuk mengestimasi nilai State of Charge secara akurat untuk mengelola dan memanfaatkan daya baterai secara optimal. Ketidakakuratan estimasi SoC dapat menyebabkan performa yang tidak optimal dan kerusakan baterai. Pendekatan tradisional dalam estimasi SoC cenderung kurang presisi, terutama di bawah kondisi dinamis. Oleh karena itu, untuk meningkatkan akurasi estimasi SoC, pada penelitian ini diusulkan model estimasi SoC menggunakan metode Support Vector Machine dengan Particle Swarm Optimization pada baterai Lithium-Ion dan Lithium-Polymer karena keduanya banyak digunakan dalam berbagai aplikasi, termasuk kendaraan listrik, perangkat seluler, dan peralatan elektronik. Hasil penelitian ini akan menunjukkan algoritma SVM dan PSO-SVM yang dapat digunakan untuk memprediksi estimasi pada baterai Lithium-Ion dan Lithium-Polymer. Berdasarkan penelitian yang telah dilakukan diperoleh hasil skor R-Squared menggunakan SVM pada Lithium-Ion sebesar 96,1% dan Lithium-Polymer sebesar 92,8%, serta menggunakan PSO-SVM pada Lithium-Ion 97,8% sebesar dan Lithium-Polymer sebesar 93,6%. hasil skor Mean Absolute Error diperoleh dengan menggunakan SVM pada Lithium-Ion sebesar 4,9% dan Lithium-Polymer sebesar 6,0%, serta menggunakan PSO-SVM pada Lithium-Ion sebesar 3,8% dan Lithium-Polymer sebesar 5,7%. hasil skor Root Mean Squeared Error diperoleh dengan menggunakan SVM pada Lithium-Ion sebesar 6,3% dan Lithium-Polymer sebesar 8,1%, serta menggunakan PSO-SVM pada Lithium-Ion sebesar 4,8% dan Lithium-Polymer sebesar 7,7%. Hasil analisis menunjukkan bahwa algoritma PSO-SVM dan SVM lebih cocok diaplikasikan pada baterai Lithium-Ion dibandingkan Baterai Lithium-Polymer, khusunya PSO-SVM.

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Batteries become a key component in the energy storage system; therefore, it is crucial to accurately estimate the State of Charge to manage and utilise the battery power optimally. Inaccuracy in SoC estimation can lead to suboptimal performance and battery damage. Traditional approaches in SoC estimation tend to lack precision, especially under dynamic conditions. Therefore, to improve the accuracy of SoC estimation, this study proposes a SoC estimation model using Support Vector Machine with Particle Swarm Optimization method for Lithium-Ion and Lithium-Polymer batteries as they are widely used in various applications, including electric vehicles, mobile devices, and electronic equipment. The results of this research will show the PSO-SVM and SVM algorithms that can be used to predict estimates for Lithium-Ion and Lithium-Polymer batteries. Based on research that has been carried out, the R-Squared score results obtained using SVM on Lithium-Ion were 96.1% and Lithium-Polymer was 92.8%, and using PSO-SVM on Lithium-Ion was 97.8% and Lithium-Polymer was 93 .6%. The Mean Absolute Error score results were obtained using SVM on Lithium-Ion of 4.9% and Lithium-Polymer of 6.0%, and using PSO-SVM on Lithium-Ion of 3.8% and Lithium-Polymer of 5.7%. The Root Mean Squeared Error score results obtained using SVM on Lithium-Ion were 6.3% and Lithium-Polymer were 8.1%, and using PSO-SVM on Lithium-Ion was 4.8% and Lithium-Polymer was 7.7%. The analysis results show that the PSO-SVM and SVM algorithms are more suitable for application to Lithium-Ion batteries compared to Lithium-Polymer Batteries, especially PSO-SVM."

"Produksi hidrogen dengan elektrolisis plasma dapat memperbesar jumlah produk hidrogen yang dihasilkan. Sedangkan, energi yang dibutuhkan tidak terlalu besar dan ramah lingkungan. Tujuan dari penelitian ini adalah mempelajari pengaruh plasma katodik dan anodik, laju alir injeksi udara, dan konsentrasi awal elektrolit terhadap produksi hidrogen dan hidrogen peroksida serta produk samping yaitu amonia dan nitrat. Elektrolisis plasma menghasilkan radikal H• dan •OH yang merupakan bahan baku dari produksi hidrogen dan hidrogen. Penelitian ini menggunakan NaOH sebagai elektrolit, aditif metanol sebanyak 2%, dan stainless steel (SS-201) sebagai elektroda. Hasil produksi hidrogen diukur dengan Gas Chromatography, hidrogen peroksida diukur dengan titrasi permanganometri, dan amonia dan nitrat menggunakan metode spektroskopi UV-Vis. Produksi hidrogen paling banyak dihasilkan pada plasma anodik (720 V), laju alir udara 0,3 lpm, dan konsentrasi awal elektrolit 0,02 M. Pada kondisi tersebut, hidrogen yang diproduksi sebanyak 430,67 mmol dan hidrogen peroksida sebanyak 1,92 mmol, energi spesifik 3,01 kJ/mmol, dan erosi elektroda sebesar 0,04 gram.

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Hydrogen production by plasma electrolysis can increase the amount of hydrogen product produced. While the energy required is not too large and environmentally friendly. The purpose of this study was to learn the effect of cathodic and anodic plasma, injected air flow rate, and initial electrolyte concentration on the production of hydrogen and hydrogen peroxide and by-products, namely ammonia and nitrate. Plasma electrolysis produces H• and •OH radicals which are the raw materials of hydrogen and hydrogen production. This study used NaOH as an electrolyte, 2% methanol as an additive, and stainless steel (SS-201) as an electrode. Hydrogen production was measured by Gas Chromatography, hydrogen peroxide was measured by permanganometric titration, and ammonia and nitrate were measured by UV-Vis spectroscopy method. Most of the hydrogen production was produced in anodic plasma (720 V), air flow rate of 0.3 lpm, and initial electrolyte concentration of 0.02 M. Under these conditions, 430.67 mmol of hydrogen was produced and 1.92 mmol of hydrogen peroxide , specific energy of 3.01 kJ/mmol, and electrode erosion of 0.04 gram."

"A special interferometric technique with high sensitivity has been devised on the basis of rainbows refractometer without the use of an additional and delicate amplitude-splitting setup. This new technique was use for the characterization of shock wave plasma induced by a Q-sw Nd-YAG laser on various kinds of metal samples under reduced gas pressures. An unmistakable signal of density jump was detected simultaneously with the emission front signal. It is proved that at the initial stage of the secondary plasma expansion, the front of the emission and the front of the blast wave was coincide and move together with time. However, at a later stage, the front of the emission will separate from that of the blast wave induced in the surrounding gas at low pressures. Using Cu and Zn samples, the experimental result showed that the separation of the emission front and blast wave front took place at 4 mm above sample surface for the laser energy of 140 mJ."

"Amonia dan nitrat merupakan senyawa yang banyak digunakan dalam berbagai industri. Elektrolisis plasma merupakan salah satu metode sintesis amonia dan nitrat yang menjanjikan karena memiliki kelebihan yaitu tidak menghasilkan emisi. Penelitian ini bertujuan untuk mengetahui bagaimana pengaruh bahan elektroda, laju alir udara, pH dan efek aditif metanol terhadap sintesis amonia nitrat melalui proses elektrolisis plasma. Penelitian dilakukan dengan reaktor 1,2 L dan trap cell 500 ml menggunakan variasi bahan elektroda stainless steel dan tungsten, laju injeksi udara 0,4 lpm, 0,6 lpm, 0,8 lpm, dan 1 lpm, variasi pH larutan reaktor 3, 3,5, dan 4 serta penambahan aditif metanol 0%v/v dan 4%v/v dengan elektrolit K₂SO₄ 0,02 M.  Pada penelitian ini, didapatkan hasil nitrat dan ketahanan erosi yang lebih baik oleh elektroda stainless steel dibandingkan tungsten yaitu 4,9 mmol nitrat dan 0,12 gram dalam waktu 30 menit. Laju alir injeksi udara didapatkan titik optimum untuk produksi amonia adalah 0,6 lpm sedangkan untuk nitrat 0,8 lpm, pH larutan reaktor yang semakin asam menghasilkan amonia yang lebih besar sedangkan untuk nitrat memiliki titik optimum di pH 3,5, dan penambahan aditif metanol menghasilkan amonia yang lebih besar sedangkan nitrat yang terproduksi menurun.

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Ammonia and nitrate is a compound that is widely used in various industries. Plasma electrolysis is a promising method of ammonia and nitrate synthesis because it has the advantage of not producing emissions. This study aims to determine how the effect of electrode material, air flow rate, pH and methanol additive effect on the synthesis of ammonia nitrate through plasma electrolysis process. The study was conducted with a 1.2 L reactor and a 500 ml trap cell using a variety of stainless steel and tungsten electrode materials, air injection rates of 0.4 lpm, 0.6 lpm, 0.8 lpm and 1 lpm, variations in reactor solution pH 3, 3.5, and 4 as well as the addition of 0%v/v and 4%v/v methanol additives with 0.02 M K₂SO₄ electrolyte. In this study, the results of nitrate and erosion resistance were better by stainless steel electrodes than tungsten, namely 4.9 mmol nitrate and 0.12 gram in 30 minutes. The air injection flow rate obtained the optimum point for ammonia production was 0.6 lpm while for nitrate 0.8 lpm, the more acidic the pH of the reactor solution, the greater the ammonia while for nitrate it had an optimum point at pH 3.5, and the addition of methanol additives produced ammonia which is greater while the nitrate produced decreases."