Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Telah dilakukan penelitian dengan tujuan untuk mengetahui pengaruh konsentrasi doping Asam Perklorat terhadap sifat dielektrik Polianilin. Sintesis PANi konduktif dilakukan melalui serangkaian proses terdiri dari reaksi oksidatif kimiawi untuk melangsungkan proses polimerisasi selama 8 jam dengan hasil berupa PANi Emeraldin (PANi-ES). Tahapan proses sintesis PANi-ES ini diikuti dengan tahapan deprotonisasi untuk membentuk PANi basa atau PANi emeraldin-base (PANi-EB). Tahapan sintesis akhir adalah berupa tahapan untuk menimbulkan sifat konduktifitas listrik PANi melalui doping asam kuat perklorat (HClO4) dengan cara mencampurkan PANi-EB sebanyak 8 gram kedalam larutan asam perklorat dengan variasi fraksi volume 80-200 ml/l. Proses pengeringan PANi melaui metode pengeringan vakum mengambil waktu 1 minggu. Selama proses polimerisasi berlangsung dilakukan pengukuran temperatur larutan, perubahan pH dan viskositas serta ukuran rata-rata partikel PANi. Sampel yang terbuat dari PANi hasil sintesis tersebut kemudian dikarakterisasi dengan spektrofotometer FTIR (Fourier Transform Infrared Spectroscopy), LCR (Inductance (L), Capacitance (C), Resistance (R)) meter , PSA (Particle Size Analyzer), dan VNA (Vector Network Analyzer) untuk mengetahui gugus fungsi, konduktivitas, ukuran partikel, dan daya serap gelombang mikro dengan rentang frekuensi tertentu (8-12 GHz). Hasil karakterisasi berdasarkan penelitian menunjukkan bahwa Polianilin (PANi) yang telah terdoping asam protonik (terprotonasi) telah menjadi polimer konduktif dan memiliki karakteristik puncak pita serapan IR pada bilangan gelombang antara 1325 cm-1 sampai 1575 cm-1. Ukuran partikel rata-rata Polianilin hasil sintesis adalah 20,7-36,24 mikrometer. Polianilin yang memiliki konduktivitas listrik tertinggi yaitu Polianilin dengan doping asam protonik HClO4 yang konsentrasinya 200 mL/L sebesar 5,2 mS/cm dan memiliki daya serapan gelombang mikro -3,45 dB pada frekuensi 10,44 GHz. ......Results of a study which aimed at to determine the effect of concentration of Perchloric Acid to the dielectric properties of Polyaniline are reported. In this study, conductive PANi was synthesized through a series of chemical oxidative reactions to carry out the polymerization process for 8 hours, which resulted in a PANi Emeraldin (PANi-ES). The synthesize processes of PANi-ES were followed by de-protonisation stage to form emeraldin-base PANi (PANi-EB). The final stage of conductive PANi was a protonisation stage to generate the electrical conductivity in synthesized PANi. This physical property was obtained through doping treatment by mixing between PANi-EB of 8 grams in mass and Perchloric Acid solution of 80-200 ml/l volume fractions. The drying process of conductive PANi was carried out through a vacuum drying method which required at least 1 week duration. During the polymerization process taking place, the temperature, a change in pH and viscosity as well as the mean size of the particles of solution were evaluated. The synthesized PANi were characterized by FTIR (Fourier Transform Infrared Spectroscopy), LCR (Inductance (L), Capacitance (C), Resistance (R)) meter, PSA (Particle Size Analyzer), and VNA (Vector Network Analyzer) to determine the functional groups, electrical conductivity, mean particle size, and the absorption of microwaves in the specific frequency range (8-12 GHz). According to the test results, it is shown that Polyaniline (PANi) doped by protonic acid (protonated) became a conductive polymer characterized by infra-red absorption peaks at wave numbers between 1325 cm-1 and 1575 cm-1. The mean particle size of changed from each starting from 20.7 to 36.24 micrometers during polymerization. PANi which has the highest electrical conductivity (5.2 mS/cm) was obtained in polyaniline which doped by HClO4 of 200 ml/L volume fraction. It has a reflection loss value of -3,45 dB at the frequency 10,44 GHz.

Abstrak :
Sintesis hidroksiapatit adalah senyawa anorganik yang membentuk bagian yang sulit jaringan tubuh manusia seperti tulang. Materi ini bertindak sebagai biokompatibilitas, bioaktivitas, dan osteokonduktivitas, sehingga membuat hidroksiapatit (HA) cocok sebagai a biomaterial. Penelitian ini bertujuan untuk menggantikan ion Magnesium (Mg), yang memiliki peran penting dalam struktur dan fungsi tubuh manusia, dalam Kalsium (Ca) ion dari Hidroksiapatit. Kristal MgHA disintesis dengan mencampurkan larutan diammonium hidrogen fosfat dan magnesium hidroksida menjadi kalsium larutan hidroksida yang kemudian diiradiasi dengan gelombang mikro, dengan variasi dalam konsentrasi Mg dan waktu iradiasi. Dari hasil XRD menunjukkan bahwa sepanjang dengan peningkatan konsentrasi Mg dan waktu iradiasi parameter kisi nilai a dan c dikurangi sebesar 0,03 dalam kisi a dan 0,01 dalam kisi c. Peningkatan Waktu iradiasi sebanding dengan peningkatan ukuran kristal (L) dan kristalinitas indeks (CI). Pada t = 35 ditemukan L = 19,08 nm dan CI = 0,14. Peningkatan Mg konsentrasi sebanding dengan peningkatan ukuran kristal dan indeks kristalinitas, peningkatan konsentrasi Mg di atas 0,6 M menunjukkan adanya saturasi dalam proses pengikatan Mg dalam struktur apatit. Proses sintering pada 900ºC meningkatkan nilai ukuran kristal dari 19,08 nm menjadi 52,09 nm dan kristalinitas indeks dari 0,14 menjadi 2,97. Dengan morfologi MgHA menghasilkan partikel berbentuk batang aglomerasi disebabkan oleh sejumlah besar konten Mg dalam apatit.

---

Hydroxyapatite synthesis is an inorganic compound that forms a difficult part of human body tissue such as bone. This material acts as biocompatibility, bioactivity, and osteoconductivity, thus making hydroxyapatite (HA) suitable as a biomaterial. This research aims to replace Magnesium (Mg) ions, which have an important role in the structure and function of the human body, in Calcium (Ca) ions from Hydroxyapatite. MgHA crystals are synthesized by mixing a solution of diammonium hydrogen phosphate and magnesium hydroxide into calcium hydroxide solution which is then irradiated with microwaves, with variations in Mg concentration and irradiation time. The XRD results show that along with the increase in Mg concentration and irradiation time the lattice parameter values ​​a and c are reduced by 0.03 in lattice a and 0.01 in lattice c. The increase in irradiation time is proportional to the increase in crystal size (L) and crystallinity index (CI). At t = 35 found L = 19.08 nm and CI = 0.14. An increase in Mg concentration is proportional to an increase in crystal size and crystallinity index, an increase in Mg concentration above 0.6 M indicates the presence of saturation in the Mg binding process in apatite structures. The sintering process at 900ºC increased the crystal size value from 19.08 nm to 52.09 nm and the crystallinity index from 0.14 to 2.97. With morphology, MgHA produces agglomeration rod-shaped particles caused by large amounts of Mg content in apatite.

Abstrak :
Tesis ini membahas pengaruh perlakuan paparan gelombang mikro dengan variasi daya dan waktu paparan gelombang mikro terhadap kandungan bambu yang larut dalam air, jumlah gula pereduksi, dan konsentrasi etanol. Hasil penelitian menunjukkan bahwa perlakuan gelombang mikro mampu meningkatkan persentase kandungan larut air. Hal ini semakin diperkuat dengan hasil gula pereduksi dan etanol yang lebih tinggi pada substrat yang telah mengalami perlakuan gelombang mikro dibanding substrat yang tidak mengalami perlakuan.

---

This thesis explains the effect of microwave exposure with power and time variation on water soluble content of bamboo, reducing sugars and also yields of ethanol. Experimental data shows that microwave exposure could increase the water soluble content of bamboo. This result is emphasized with result of reducing sugars and ethanol yield that higher in substrate that had been exposed on microwave radiation.

Abstrak :
Tesis ini membahas metode penghilangan moisture batubara Indonesia peringkat rendah dengan menggunakan gelombang mikro. Diharapkan metode ini mampu mengurangi waktu pemanasan dan mengurangi moisture re-adsorpsi batubara. Berdasarkan penelitian, waktu penghilangan moisture pada batubara Indonesia dipengaruhi oleh kandungan awal total moisture, ukuran partikel, massa sampel, dan daya yang diberikan. Pada pemanasan gelombang mikro dengan daya 800 W, Batubara Melawan (kandungan awal total moisture: 24,18 %) memerlukan waktu penghilangan moisture yang paling pendek yaitu sekitar 1,5 - 2 menit sedangkan Batubara Pendopo (kandungan awal total moisture: 58,27 %) memerlukan waktu terlama yaitu antara 3 - 3,5 menit. Akibat penghilangan moisture, batubara Indonesia mengalami kenaikan nilai kalor, volatile matter dan fixed carbon; namun tidak terjadi perubahan signifikan pada fuel ratio. Moisture re-adsorpsi pada Batubara Indonesia yang telah mengalami penghilangan moisture akibat gelombang mikro tidak dipengaruhi oleh ukuran partikel dan daya yang diberikan. ......This research aims to find a method of removing moisture Indonesian low rank coal Indonesia by using microwaves. This method is expected to reduce heating time and reduce the moisture re-adsorption of coal. Based on the study, the removal of moisture in coal Indonesia affected by the initial total moisture content, particle size, sample mass, and power delivered. In the microwave heating power of 800 W, the Melawan Coal (initial total moisture content: 24.18%) removal of moisture takes the shortest is about 1.5 - 2 minutes while the Pendopo Coal (initial total moisture content: 58.27%) requires the longest time is between 3 - 3.5 minutes. The affect of the removal of moisture, Indonesian coal has increased calorific value, volatile matter and fixed carbon; but there was no significant change on to the fuel ratio. Moisture readsorption on Indonesian coal which have removal of moisture by the microwaves are not affected by particle size and power that are given.

Abstrak :
Pertumbuhan butir pada temperatur 1100oC, 1200oC, dan 1300oCkristal LaxBa(1-x)Fe0.25Mn0.5Ti0.25O3 dipelajari. Material sampel dipreparasi menggunakan teknik pengaloyan mekanik (mechanical alloying) dengan waktu penggilingan (high ball energy milling) selama 30 jam. Sintering dilakukan selama 0, 1, 3 dan 6 jam. Material dianalisa menggunakan sinar X. Besar ukuran butir dihitung menggunakan persamaan Debye-Scherrer berdasarkan profil difraksi sinar X-nya. Sifat magnetik diukur menggunakan pemagraf. Sedangkan serapan gelombang mikro diukur menggunakan alat Network Analyzer (VNA) dengan metode Transmission/Reflection Line (TRL). Semua pengukuran dilakukan pada temperatur kamar. Hasil penelitian menunjukkan bahwa persamaan pertumbuhan butir kristal La0.25Ba0.75Fe0.25Mn0.5Ti0.25O3 mengikuti model persamaan laju difusi. Hasil serapan gelombang mikro menunjukkan adanya serapan pada frekuensi 11-15 GHz. Serapan ini relatif lebih kecil jika dibandingkan dengan serapan material basisnya yakni LaFe0.25Mn0.5Ti0.25O3. Namun daerah serapannya relatif lebih luas daripada material basis tersebut. ...... Growth of La0.25Ba0.75Fe0.25Mn0.5Ti0.25O3 in the temperatur e1100oC, 1200oC, dan 1300oC during 0, 1, 3 and 6 hours sinteringwas investigated. Sampels was prepared by mechanical alloying techique with high ball energy milling. Milling time is 30 hours. Sample was analized using x-ray diffraction.Grain size was calculated using Debye-Scherrer equation based on their x-ray diffraction profiles. Material absorbance properties was measured using Network Analyzer (VNA) with Transmission/ Reflection Line (TRL) measurement technique. All analysis was conducted in room temperature. Data showed that grain growth of La0.25Ba0.75Fe0.25Mn0.5Ti0.25O3 has followed diffusion rate equation model of. Whilst it microwave absorbance measurement data performed its wide absorbance in the fequency range 11-15 GHz. Despite its relatively small absorbance intensity, La0.25Ba0.75Fe0.25Mn0.5Ti0.25O3 has broader bandwith comparing to its base material LaFe0.25Mn0.5Ti0.25O3.

Abstrak :
[ABSTRAK
Penggunaan gelombang mikro dalam beberapa tahun terakhir ini mengalami peningkatan yang sangat pesat seiring berkembangnya teknologi komunikasi dan informasi. Hal ini menimbulkan masalah baru yakni terjadinya polusi gelombang mikro. Untuk mengimbangi dampak negatif polusi interferensi gelombang elektromagnetik, para peneliti mencoba mengembangkan material penyerap gelombang elektromagnetik. Salah satu material yang menjadi kandidat potensial untuk aplikasi penyerap gelombang mikro adalah material berbasis lantanum manganat. Pada penelitian ini dipelajari rekayasa struktur material berbasis lantanum manganat dengan sistem La0,67Ba0,33Mn1-xNix/2Tix/2O3 (x = 0; 0,02; 0,04 dan 0,06). Fasa tunggal senyawa La0.67Ba0.33Mn1-xNix/2Tix/2O3 berhasil dibuat melalui proses pemaduan mekanik menggunakan prekusor-prekusor La2O3, MnCO3, BaCO3, TiO2, dan NiO dengan tingkat kemurnian tinggi. Selanjutnya serbuk hasil pemaduan mekanik menjalani perlakuan pemanasan pada suhu 1200oC selama 10 jam. Material yang telah dipanaskan kemudian dihaluskan kembali selama 20 jam. Hasil refinement pola difraksi sinar X menunjukkan bahwa senyawa La0,67Ba0,33Mn1-xNix/2Tix/2O3 memiliki strukstur kristal monoklinik untuk seluruh variasi x. Kurva histerisis sampel menunjukkan bahwa material ini termasuk magnet lunak. Hasil evaluasi distribusi ukuran partikel material dengan komposisi terbaik yakni La0,67Ba0,33Mn0,06Ni0,03Ti0,03O3 adalah 82,4 nm. Hasil pengujian sifat serapan gelombang mikro pada rentang 8-12,4 GHz menunjukkan material mampu mereduksi gelombang mikro hingga 94 % pada frekuensi 11,4 GHz. Dengan demikian senyawa La0,67Ba0,33Mn1-xNix/2Tix/2O3 dapat dijadikan sebagai material penyerap gelombang mikro.;

---

ABSTRACT
In recent years, application of microwaves has been increased along with the development of communication and information technology and highly produces electromagnetic wave interference. To solve this problem, scientist tries to develop a new material that could absorb electromagnetic waves. One of potential candidates for absorbing materials is lanthanum manganese-based system. In this research, La0.67Ba0.33Mn1-xNix/2Tix/2O3 (x = 0, 0.02, 0.04, and 0.06) compound were studied as a microwaves absorber materials. Single phase of La0.67Ba0.33Mn1-xNix/2Tix/2O3 were successfully synthesized by mechanical alloying method. The mixture of all precursors were first mechanically milled for 20 hours and then sintered at a temperature of 1200oC for 10 h in which a fully crystalline material is ensured. The sintered materials were then re-milled for 20 hours to obtain powder-based nanoparticle. X-ray diffraction refinement shows that the samples have monoclinic structure at all x compositions. The hysteresis curve evaluation showed that the sample materials is soft magnetic. The best composition of La0.67Ba0.33Mn1-xNix/2Tix/2O3 with x = 0.06 has been evaluated. The compound has 82.4 nm particle size distributions and it is able to absorb up to 94% microwaves at 11.4 GHz. The study concluded the material of La0.67Ba0.33Mn1-xNix/2Tix/2O3 have a good potential to be a candidate of microwaves absorbing materials. ;In recent years, application of microwaves has been increased along with the development of communication and information technology and highly produces electromagnetic wave interference. To solve this problem, scientist tries to develop a new material that could absorb electromagnetic waves. One of potential candidates for absorbing materials is lanthanum manganese-based system. In this research, La0.67Ba0.33Mn1-xNix/2Tix/2O3 (x = 0, 0.02, 0.04, and 0.06) compound were studied as a microwaves absorber materials. Single phase of La0.67Ba0.33Mn1-xNix/2Tix/2O3 were successfully synthesized by mechanical alloying method. The mixture of all precursors were first mechanically milled for 20 hours and then sintered at a temperature of 1200oC for 10 h in which a fully crystalline material is ensured. The sintered materials were then re-milled for 20 hours to obtain powder-based nanoparticle. X-ray diffraction refinement shows that the samples have monoclinic structure at all x compositions. The hysteresis curve evaluation showed that the sample materials is soft magnetic. The best composition of La0.67Ba0.33Mn1-xNix/2Tix/2O3 with x = 0.06 has been evaluated. The compound has 82.4 nm particle size distributions and it is able to absorb up to 94% microwaves at 11.4 GHz. The study concluded the material of La0.67Ba0.33Mn1-xNix/2Tix/2O3 have a good potential to be a candidate of microwaves absorbing materials. , In recent years, application of microwaves has been increased along with the development of communication and information technology and highly produces electromagnetic wave interference. To solve this problem, scientist tries to develop a new material that could absorb electromagnetic waves. One of potential candidates for absorbing materials is lanthanum manganese-based system. In this research, La0.67Ba0.33Mn1-xNix/2Tix/2O3 (x = 0, 0.02, 0.04, and 0.06) compound were studied as a microwaves absorber materials. Single phase of La0.67Ba0.33Mn1-xNix/2Tix/2O3 were successfully synthesized by mechanical alloying method. The mixture of all precursors were first mechanically milled for 20 hours and then sintered at a temperature of 1200oC for 10 h in which a fully crystalline material is ensured. The sintered materials were then re-milled for 20 hours to obtain powder-based nanoparticle. X-ray diffraction refinement shows that the samples have monoclinic structure at all x compositions. The hysteresis curve evaluation showed that the sample materials is soft magnetic. The best composition of La0.67Ba0.33Mn1-xNix/2Tix/2O3 with x = 0.06 has been evaluated. The compound has 82.4 nm particle size distributions and it is able to absorb up to 94% microwaves at 11.4 GHz. The study concluded the material of La0.67Ba0.33Mn1-xNix/2Tix/2O3 have a good potential to be a candidate of microwaves absorbing materials. ]