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"ABSTRACTThe construction and excitation circuit of carbon dioxide laser 616 mm long is described. The dependence of the pulse emission energy on the energy supplied to the discharge, the pressure and composhdon gaseous mixture is presented. The emission energy is 1-2 Joules. The emission pulse isexpected to cover range from 100 ns - 200 ns."

"Peningkatan konsentrasi CO2 di atmosfer memberikan dampak kenaikan suhu dan perubahan iklim. Adsorpsi dengan adsorben merupakan pemisahan CO2 yang memiliki konsumsi energi dan biaya yang rendah. Karbon aktif dipilih sebagai adsorben karena memiliki kapasitas adsorpsi CO2 yang lebih baik pada tekanan atmosfer dan suhu yang tinggi. Ranting tanaman teh dapat dimanfaatkan sebagai bahan baku pembuatan karbon aktif karena memiliki kandungan karbon yang tinggi yaitu 53%. Penelitian ini dilakukan untuk mendapatkan pengaruh pembuatan karbon aktif dari ranting teh melalui karbonisasi 400°C selama 1 jam menggunakan gas N2, dan aktivasi fisika pada suhu aktivasi yang divariasikan, yaitu 600, 700, dan 800°C selama 4 menit dengan pemanfaatan alat APS (arc plasma sintering), terhadap pembentukan pori, luas permukaan, pembentukan gugus fungsi, serta struktur dan ukuran kristal. Karakterisasi karbon aktif didapatkan melalui SEM, BET, FTIR, dan XRD. Kemudian, melalui alat TPD-CO2, jumlah kapasitas adsorpsi CO2 pada karbon aktif dari ranting teh dapat terukur. Melalui proses karbonisasi dan aktivasi fisika, didapatkan karbon aktif dengan luas permukaan 86,668 m2/g dan kapasitas adsorpsi 2,057 mmol/g yang optimal pada suhu aktivasi fisika 800°C.

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Increasing CO2 concentrations in the atmosphere have an impact on rising temperatures and climate change. Adsorption with adsorbents is a CO2 separation that has low energy consumption and costs. Activated carbon was chosen as an adsorbent because it has better CO2 adsorption capacity at atmospheric pressure and high temperature. Tea plant twigs can be used as raw material for making active carbon because they have a high carbon content, namely 53%. This research was conducted to obtain the effect of making activated carbon from tea twigs through carbonization at 400°C for 1 hour using N2 gas, and physical activation at varied activation temperatures, namely 600, 700, and 800°C for 4 minutes using the APS (arc plasma sintering), on pore formation, surface area, formation of functional groups, as well as crystal structure and size. Characterization of activated carbon was obtained through SEM, BET, FTIR, and XRD. Then, using the TPD-CO2, the amount of CO2 adsorption capacity on activated carbon from tea twigs can be measured. Through the carbonization and physical activation process, activated carbon was obtained with a surface area of 86,668 m2/g and an adsorption capacity of 2,057 mmol/g which was optimal at a physical activation temperature of 800°C."

"Proses ekstraksi zat padat dapat dilakukan menggunakan fluida karbon dioksida dalam keadaan superkritis yang juga disebut sebagai supercritical fluid extraction (SCFE). SCFE membutuhkan properti tertentu dari zat padat yang hanya dapat didapat melalui penelitian laboratorium, sehingga memakan waktu dan biaya. Sebelumnya sudah dibuat sebuah model yang dapat menggambarkan perilaku zat padat dalam proses SCFE. Studi ini bertujuan untuk memperbaharui model tersebut menggunakan data yang lebih baru, serta membandingkan akurasi model yang lama dengan yang studi ini hasilkan. Dari evaluasi simulais, didapat korelasi baru dengan average absolute deviation (AALD) sebesar 25, nilai yang jauh lebih besar dibandingkan dengan korelasi dari studi sebelumnya, sehingga korelasi dengan data yang sudah diperbaharui tidak seakurat yang sebelumnya dalam memprediksi kelarutan zat padat dalam karbon dioksida superkritikal.

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Extraction of solid compounds can be done using supercritical carbon dioxide, which is also known as Supercritical Fluid Extraction (SCFE). SCFE requires certain properties to be known that can only be obtained from laboratory experiments, thus requiring time and expense. Previously a model has been created that can illustrate the behavior of solids in an SCFE process. This study aims to update the model by using more recent data, and compare the accuracy of the old model and the one produced by this study. The result is a new correlation with an AALD of 25, much bigger than the correlation produced by the previous study, therefore making it much more inaccurate at predicting solid solubility in supercritical carbon dioxide."

"Sistem pemonitor konsentrasi relatif karbon dioksida dalam ruangan berbasis sensor gas TGS4161 telah berhasil dibuat. Sistem ini dikendalikan dengan menggunakan mikrokontroler ATmega128. Mikrokontroler digunakan untuk mengatur keseluruhan sistem. Salah satu fungsi mikrokontroler adalah untuk mengolah GGL yang dihasilkan sensor menjadi satuan ppm. Pada sistem ini, konsentrasi CO² dihitung dengan cara menghitung perubahan relatif output sensor pada pengukuran saat ini dengan output sensor pada udara bersih (dianggap 400 ppm CO²). Proses konversi ke dalam satuan ppm dilakukan dengan menggunakan hubungan linear antara ∆GGL dengan konsentrasi CO² pada skala logaritmik. Dengan demikian perhitungan konsentrasi absolut karbon dioksida tidak dapat dilakukan. Sistem ini mampu menghitung konsentrasi relatif karbon dioksida dari 400 ppm sampai 10.000 ppm. Hasil perhitungan kemudian ditampilkan dengan menggunakan LCD 2x16. Sistem yang dibuat ini dilengkapi dengan data logger untuk menyimpan data-data yang dibaca oleh mikrokontroler. Data-data ini disimpan ke dalam microSD card sehingga dapat diolah lebih lanjut menggunakan PC. Sistem ini juga berfungsi sebagai kontrol ventilasi udara secara otomatis.

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An indoor carbon dioxide monitoring system has been successfully constructed using a TGS4161 gas sensor. This system is controlled using ATmega128 microcontroller. Microcontroller used to control the whole system. One of the task is for converting EMF which is produced by a sensor into ppm unit. In this system, the CO² concentration is calculated by measuring the relative change of sensor output at the measuring point from sensor output in clean air (assumed to be 400ppm of CO²). Conversion into ppm unit is done by using relationship between ∆EMF and CO² gas concentration on a logarithmic scale. Thus, absolute concentration measurement can not be done. This system is able to calculate the relative concentration of carbon dioxide from 400 ppm to 10,000 ppm. Calculation results are then displayed using 2x16 LCD. This system is equipped with data logger to store the data read by microcontroller. The data can be stored in microSD card for further processing using PC. This system also can be used as automatic ventilation control."

"[ABSTRAKPenelitian ini mengevaluasi kinerja absorpsi gas CO2 dari campurannya denganCH4 melalui membran kontaktor superhidrofobik. Kinerja kontaktor membransuperhidrofobik ini ditinjau dari empat parameter utama dengan variasi laju alirpelarut DEA (100, 300 dam 500 mL/menit) dan jumlah serat membran kontaktor(2000 dan 8000). Hasil penelitian ini menunjukkan bahwa kenaikan laju alir pelarutDEA meningkatkan kinerja kontaktor membran superhidrofobik, dalam halkoefisien perpindahan massa, fluks dan efisiensi penyerapan CO2. Sedangkankenaikan jumlah serat membran akan menurunkan koefisien perpindahan massadan fluks CO2. Namun, meningkatkan efisiensi penyerapan CO2 dan acid loading.Koefisien perpindahan massa dan fluks CO2 tertinggi yang didapatkan padapenelitian ini berturut-turut adalah 2,31 x 10-4 cm/s dan 7,15 x 10-6 mmol/cm2s padalaju alir DEA 500 mL/menit dan jumlah serat membran 2000. Sedangkan efisiensipenyerapan CO2 tertinggi adalah 72% pada laju alir DEA 500 mL/menit dan jumlahserat membran 8000.ABSTRACTThis study evaluates performance of CO2 absorption from its mixture with CH4through membran contactor superhydrophobic. Superhidrophobic membranecontactor performance is observed using four main parameters by varying the flowrate of solvent DEA (100, 300 dam 500 mL/min) and the number of fiber membranecontactors (2000 and 8000). The results showed that increasing DEA solvent flowrate increase superhidrophobic membrane contactor performance, in terms of masstransfer coefficient, flux and efficiency removal of CO2. While increasing thenumber of fiber membrane will reduce the mass transfer coefficient and CO2 flux.However, it will increase the efficiency removal of CO2 and acid loading. Thehighest mass transfer coefficient and CO2 flux obtained in this study arerespectively 2,31 x 10-4 cm/s and 7,15 x 10-6 mmol/cm2s on DEA flow rate of 500mL/min and the number of fiber membranes 2000. The highest CO2 absorptionefficiency is 72% at DEA flow rate of 500 mL/min and the number of fibermembranes 8000.;This study evaluates performance of CO2 absorption from its mixture with CH4through membran contactor superhydrophobic. Superhidrophobic membranecontactor performance is observed using four main parameters by varying the flowrate of solvent DEA (100, 300 dam 500 mL/min) and the number of fiber membranecontactors (2000 and 8000). The results showed that increasing DEA solvent flowrate increase superhidrophobic membrane contactor performance, in terms of masstransfer coefficient, flux and efficiency removal of CO2. While increasing thenumber of fiber membrane will reduce the mass transfer coefficient and CO2 flux.However, it will increase the efficiency removal of CO2 and acid loading. Thehighest mass transfer coefficient and CO2 flux obtained in this study arerespectively 2,31 x 10-4 cm/s and 7,15 x 10-6 mmol/cm2s on DEA flow rate of 500mL/min and the number of fiber membranes 2000. The highest CO2 absorptionefficiency is 72% at DEA flow rate of 500 mL/min and the number of fibermembranes 8000.;This study evaluates performance of CO2 absorption from its mixture with CH4through membran contactor superhydrophobic. Superhidrophobic membranecontactor performance is observed using four main parameters by varying the flowrate of solvent DEA (100, 300 dam 500 mL/min) and the number of fiber membranecontactors (2000 and 8000). The results showed that increasing DEA solvent flowrate increase superhidrophobic membrane contactor performance, in terms of masstransfer coefficient, flux and efficiency removal of CO2. While increasing thenumber of fiber membrane will reduce the mass transfer coefficient and CO2 flux.However, it will increase the efficiency removal of CO2 and acid loading. Thehighest mass transfer coefficient and CO2 flux obtained in this study arerespectively 2,31 x 10-4 cm/s and 7,15 x 10-6 mmol/cm2s on DEA flow rate of 500mL/min and the number of fiber membranes 2000. The highest CO2 absorptionefficiency is 72% at DEA flow rate of 500 mL/min and the number of fibermembranes 8000., This study evaluates performance of CO2 absorption from its mixture with CH4through membran contactor superhydrophobic. Superhidrophobic membranecontactor performance is observed using four main parameters by varying the flowrate of solvent DEA (100, 300 dam 500 mL/min) and the number of fiber membranecontactors (2000 and 8000). The results showed that increasing DEA solvent flowrate increase superhidrophobic membrane contactor performance, in terms of masstransfer coefficient, flux and efficiency removal of CO2. While increasing thenumber of fiber membrane will reduce the mass transfer coefficient and CO2 flux.However, it will increase the efficiency removal of CO2 and acid loading. Thehighest mass transfer coefficient and CO2 flux obtained in this study arerespectively 2,31 x 10-4 cm/s and 7,15 x 10-6 mmol/cm2s on DEA flow rate of 500mL/min and the number of fiber membranes 2000. The highest CO2 absorptionefficiency is 72% at DEA flow rate of 500 mL/min and the number of fibermembranes 8000.]"

"ABSTRACTThe carbon dioxide laser is one of the most versatile types on the marked today. It emits infrared radiation between 9 and 11 micrometer (μm) either at a single line selected by the user or on the strongest line in untuned cavities. It can produce continuous output power output powers ranging from well under 1W for scientific applications to many kilowatts for material working. It can generate pulses from the nanosecond to millisecond regimes. Custom made CO2 lasers have produced continues beams of hundreds of kilowatts for military laser weapon research (Hecht 1984) or nanosecond long pulses of 40 kilo joules (kj) for research in laser induced nuclear fusion (Los Alamos National Laboratory 1982). This versatility comes from the fact that there are several distinct types of carbon dioxide lasers. While they share the same active medium, they have important differences in internal structure and more important to the user in lunch oral characteristic. In theory the structural variations could range over a really continuous spectrum, but manufactures have settled on a few standard configurations which meet most user needs. This users see several distinct types, such as waveguide, low power sealed tube, high power following gas, and pulsed transversely excited CO2 lasers. On TEA lasers discharge instabilities make continuous wave operation impractical at gas pressures above about 100 torr (13,3 MPa). How everit is possible to produce pulses lasting tens of nanosecond to microseconds. Such lasers are called transversely excited atmospheric (TEA) lasers because they operate at or near atmospheric pressure, although same times the term is applied to pulsed transversely excited CO2 lasers which operate at higher or lower pressures. The TEA lasers prime attraction of high power per unit volume of laser gas and have fairly complex power requirements because of the nature of their pulsed operation. Typically same energy in the form of electrons or ultraviolet photons is discharged into the laser gas slightly before the main pulse to make it possible to obtain higher output power. In this thesis, basic theory of the Carbon dioxide laser are presented in section II. Section III descibe Optical Transducer. Section IV contains the characterization of carbon dioxide laser with the results and graphs. Finally some conclusion regarding our discussion are summarized in section V."

"ABSTRAKPada penelitian ini telah berhasil disintesis karbon mesopori terimpregnasi trietilentetraamina (TETA) dan metil dietanol amina (MDEA). Karbon mesopori dibuat melalui metode soft template dengan phloroglucinol dan formaldehida sebagai prekursor karbon, Pluronic F-127 sebagai agen pembentuk struktur dan HCl sebagai katalis. Pada penelitian ini, karbon aktif komersil terimpregnasi TETA dan MDEA digunakan sebagai pembanding. Karbon mesopori dan karbon aktif terimpregnasi TETA dan MDEA dikarakterisasi dengan FTIR, CHN analyzer dan analisa luas permukaan untuk memperhatikan pengaruh impregnasi terhadap struktur pada material tersebut.Impregnasi meningkatkan kadar nitrogen pada karbon mesopori dengan meningkatnya konsentrasi TETA dan MDEA yang diimpregnasi. Spektrum FT-IR karbon mesopori terimpregnasi TETA memiliki puncak-puncak serapan yang merupakan karakteristik bilangan gelombang dari TETA. Spektrum FT-IR karbon mesopori terimpregnasi MDEA memiliki puncak-puncak serapan yang merupakan karakteristik bilangan gelombang dari MDEA. Hasil analisis permukaan memperlihatkan impregnasi TETA dan MDEA menurunkan luas permukaan dan volume pori namun masih mempertahankan sifat mesoporinya. Hasil ini memperlihatkan karbon mesopori terimpregnasi TETA dan MDEA berhasil disintesis.Adsorpsi CO2 dilakukan dengan autoclave sistem batch. Hasil adsorpsi CO2 memperlihatkan karbon aktif memiliki kapasitas adsorpsi CO2 lebih besar dibandingkan karbon mesopori. Hasil adsorpsi CO2 pada karbon mesopori terimpregnasi TETA dan MDEA memiliki kapasitas adsorpsi CO2 yang meningkat dibandingkan karbon mesopori. Sedangkan kapasitas adsorpsi CO2 pada karbon aktif terimpregnasi TETA dan MDEA mengalami penurunan. Regenerasi adsorben memperlihatkan penurunan kapasitas adsorpsi CO2 selama pengujian lima kali siklus. Hal ini diakibatkan dari CO2 yang teradsorp sebelumnya belum sepenuhnya hilang sehingga mengganggu adsorpsi berikutnya. Selain itu, pemanasan pada saat regenerasi menyebabkan terjadi desorpsi amina pada karbon mesopori terimpreganasi TETA dan MDEA.

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ABSTRACTThis research has successfully synthesized triethylenetetraamine (TETA) and methyl diethanol amine (MDEA) impregnated-mesoporous carbon. Mesoporous carbon was prepared through soft-template method with phloroglucinol and formaldehyde as carbon precursors, Pluronic F-127 as the structure directing agent and HCl as the catalyst. In this research, TETA and MDEA-impregnated activated carbon were used as comparison. TETA and MDEA impregnated mesoporous carbon and activated carbon were characterized by FTIR, CHN analyzer and surface area analysis to observe the effect impregnation on material structure.Impregnation increased the nitrogen content on the mesoporous carbon with increasing concentrations of TETA and MDEA impregnation. The FT-IR spectrum of TETA impregnated mesoporous carbon had absorption peaks that TETA?s characteristic wavenumber. The FT-IR spectrum of MDEA impregnated mesoporous carbon had absorption peaks MDEA?s characteristic wavenumber. The results of surface analysis showed impregnation TETA and MDEA decreased surface area and pore volume but still maintained mesoporous character. These results showed that TETA and MDEA-impregnated mesoporous carbon were successfully synthesized.CO2 adsorption performed with autoclaved-reactor in batch system. CO2 adsorption result showed the CO2 adsorption capacity of activated carbon higher than the mesoporous carbon. CO2 adsorption from TETA and MDEA impregnated mesoporous carbon have CO2 adsorption capacity increased than the mesoporous carbon. But the CO2 adsorption capacity of the TETA and MDEA-impregnated activated carbon decreased. Regeneration adsorbent showed decrease in CO2 adsorption capacity during five time cycles test. This is due to the CO2 adsorbed previously didn?t completely removed and interfere next adsorption. Futhermore, the heating for regeneration caused desorption amine on TETA and MDEA impregnated mesoporous carbon."

"Modifikasi dilakukan pada sistem katalis yang terdiri dari logam Ni dan Zn sebagai promotor dengan penyangga karbon aktif agar dapat menurunkan keasaman dalam menghidrogenasi CO dan CO2 secara simultan menjadi metanol. Karbon aktif berasal dari batubara bituminous yang mengandung unsur Si, Al, Fe, Ca, S dan Mg. Katalis dibuat secara impregnasi dilanjutkan dengan pengeringan dalam oven 110oC selama 20 jam dan kalsinasi pada suhu 400oC selama 4 jam. Tahap awal uji aktivitas katalis didahului oleh reduksi secara in-situ dalam fixed bed reactor dengan massa katalis 0.5 gram selama 1.5 jam pada suhu 350oC menggunakan gas H2 sebagai pereduksi. Proses hidrogenasi CO dan CO2 dilangsungkan pada kondisi 20 bar dan suhu 270oC selama 4 jam kontinyu. Sebagai umpan digunakan campuran gas H2/CO/CO2/N2 dengan komposisi 69.98% H2, 17.78% CO, 6.41% CO2, 5.75% N2 dan 0.08% CH4. Katalis dengan loading Ni tertinggi (57.58% Ni dan 9.46% Zn) dengan keasaman 0.1565 mmol/g.Kat dan luas area permukaan 758.04 m2/gram menghasilkan konversi CO2 tertinggi sebesar 97.72% dan konversi CO sebesar 12.34% untuk membentuk CH4, C2H4, C2H6 dan metanol.

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Modifications carried out on a catalyst system consisting of Ni metal and Zn as a promoter with activated carbon as a support in order to lower the acidity in the hydrogenate of CO and CO2 that simultaneously produce methanol. Activated carbon derived from bituminous coal containing elements of Si, Al, Fe, Ca, S and Mg. The catalyst is made by impregnation followed by drying in an oven 110oC for 20 hours and calcination at a temperature of 400oC for 4 hours. The initial stage of the catalyst activity test was preceded by in-situ reduction in the fixed bed reactor with a catalyst mass of 0.5 grams for 1.5 hours at a temperature of 350oC using H2 as a reductant. The process of hydrogenation of CO and CO2 held in conditions of 20 bar and a temperature of 270oC for 4 hours continuously. gas mixture (H2 / CO / CO2 / N2) is used as a feedstock with each composition 69.98% H2, 17.78% CO, 6:41% CO2, 5.75% N2 and 0.08% CH4. Nickel catalyst with the highest loading (57.58% 9:46% Ni and Zn) with the acidity 0.1565 mmol /g.Kat and surface area 758.04 m2/gram have the highest conversion of CO2 97.72% and the conversion of CO reach 12.34% to form CH4, C2H4, C2H6 and methanol."