Makara Journal of Science
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PENENTUAN KONSTANTA OPTIS DI DAERAH ABSORPSI FUNDAMENTAL MENGGUNAKAN FORMULASI FOROUHI DAN BLOOMER UNTUK LAPISAN TIPIS AMORF SILIKON KARBON (a-SiC:H)
No full textAn expression of the imaginary and real parts of the complex refractive index derived by Forouhi and Bloomer have been applied to obtain wider energy range of optical constants for amorphous silicon carbon (a-SiC:H) films deposited by dc sputtering method using silicon and graphite targets. Excellent agreement was obtained between the formula and experimentally measured values of both n(E) and k(E). The optical constants obey Kramers-Kronig dispersion relation and show a maximum at high-energy range. The dependence of five parameters to carbon concentration and the variation of optical constants with composition for both targets will be discussed.Keywords: optical constants, absorption, amorphous silicon carbon, sputterin
SEMI-SINTESIS VANILI DARI GUAIAKOL VIA REAKSI REIMERTIEMANN YANG DIKATALISIS DENGAN KATALIS TRANSFER FASE/PTC: [18]-CROWN ETHER-6
No full textReimer-Tiemann reaction belongs to the group of the electrophylic substitution reaction (SE), and principally, thisreaction consists of three steps reactions, namely: 1. formation of dichlorocarbene from chloroform by action of base(i.e. KOH), 2. reaction of dichlorocarbene as electrophyl to the benzene (or general aromatic) nucleus, 3. hydrolysis ofthe formed dichloromethyl benzene to the derivative of benzaldehyde. In this work has been carried out the modification of Reimer-Tiemann reaction with the goal to synthesize vanillin from guaiacol (o-methoxyphenol) as wellas to compare with the conventional Reimer-Tiemann reaction. By the way, the modification of Reimer-Tiemann by using phase transfer catalyst and ethanol as co-solvent can obviously enhance the yield of vanillin up to 51.2% compared with the yield of conventional Reimer-Tiemann to synthesize of vanillin (up to 24.4%).Key words: Reimer-Tiemann reaction, guaiacol, chloroform, vanilli
PEMANTAUAN KADAR LOGAM BERAT DALAM SEDIMEN DI PERAIRAN TELUK JAKARTA
No full textObservation on Heavy Metals in Sediment of Jakarta Bay Waters. Observation on heavy metals in Jakarta Bay, from June and September 2003. Heavy metals Pb in sediment at the West have been conductet of Jakarta Bay Waters varied between Pb = 8,49-31,22 ppm, Cd = <0,001-0,47 ppm, Cu = 13,81-193,75 ppm, Zn = 82,18-533,59 ppm and Ni = 0,99-35,38 ppm,while those at the Center of Jakarta Bay, varied between Pb = 2,21-69,22 ppm, Cd = <0,001-0,28 ppm, Cu = 3,36-50,65 ppm, Zn = 71,13-230,54 ppm and Ni = 0,42-15,58 ppm and at the East of Jakarta Bay, Pb content varied between 0,25-77,42 ppm, Cd = <0,001-0,42 ppm, Cu = 0,79-44,94 ppm, Zn = 93,21-289,00 ppm and Ni = 0,42-128,47 ppm. Hevy metals content in sediment the West of Jakarta Bay was high of equivalent the Center and East of Jakarta Bay. At than those composition sediment at the west was black, that indicated high heavy metals content. Keywords: Heavy metal, Sediment, Jakarta Bay, Timbal, Cadmium, Zink, Nikel and C
PENGARUH ANIL TERMAL TERHADAP BESARAN OPTIS LAPISAN TIPIS a-SiC:H HASIL METODE DC SPUTTERING I. TARGET SILIKON
No full textThe Effect of Thermal Annealing on the Optical Properties of a-SiC:H Films Produced by DC Sputtering Methods: I. Silicon Target Case. The effects of thermal annealing treatment on the optical properties of amorphous silicon carbon films deposited by silicon target in an argon, methane and hydrogen gas mixture have been studied using ultra violet-visible (uv-vis) spectroscopy. Both n and α, and consequently the real and imaginary parts of the dielectric constant, show a considerable variation with subsequent annealing up to annealing temperature 500 °C, with the most rapid changes occurring for temperature 300 °C. The films tend denser as the annealing temperature increased up to 500°C. The optical gap improved slightly upon annealing, where as the disorder of the amorphous network reduced. The annealing treatment produces reorganization of the amorphous network since thermal annealing results in dissociation of hydrogenated bonds (Si-H and C-H).Keywords: optical constants, amorphous silicon carbon, sputtering, thermal annealing, hydrogen, voi
PENGEMBANGAN METODE BARU PENENTUAN CHEMICAL OXYGEN DEMAND (COD) BERBASIS SEL FOTOELEKTROKIMIA: KARAKTERISASI ELEKTRODA KERJA LAPIS TIPIS TiO2/ITO
No full textDevelopment of A Novel Methode for COD (Chemical Oxygen Demand) Measurement based on Photoelectrochemical Cell: Characterization of TiO2/ITO Film Working Electrode. Nanosize TiO2 film, immobilized on an ITO (Indium Tin Oxide) glass, was successfully fabricated. The film was prepared by a dip coating technique in a hydrothermal sol-gel system and subjected to a heat treatment at 100°C up to 450°C. Characterization of the film by XRD, AFM, BET methods revealed the occurrence of anatase form and 9.64 nm in crystallite size; having three dimensional profile and roughness with height of typically 9.8 nm; and surface area of 58.21 m2/g. The film then was employed as a working electrode in a photo electrochemical system (PES). This PES generated a photocurrent that proportional to the organic chemical concentration in the water sample. Integration of the photocurrent versus time gives a charge (Q) that represent the event of complete mineralization of organic chemical in the TiO2 surface and can be correlated to the Chemical Oxygen Demand (COD) of measured water. This system has a potential to be developed for a novel COD sensor. Keywords: photoelectro catalysis, titanium dioxide, Chemical Oxygen Demand, CO
KOMPOSISI KEBERADAAN KRUSTASEA DI MANGROVE DELTA MAHAKAM KALIMANTAN TIMUR
No full textMangrove area, Mahakam Delta, East Kalimantan. The aim of this research was to analyze the diversity and the richness of crustacean. The research was done in the locations where dense area (Muara Ilu I), moderate area (Muara Ilu II, P. Tunu) and rare area of mangroves Muara Pantuan (P. Lagenting Luar). The transect research method was used stand upright line of the seashore for mangrove and crustacean. The result of environment parameter shows relative in good condition for living mangrove and crustacean organisms. Total founded crustacean were 40 species and 9 families. The 38 species were non economic values and 2 species were economic values: Varuna yui and Scylla olivacea, also founded 2 new species: Metaplax sp. nov. (Grapsidae) and Macrophthalmus sp. nov. (Sesarmidae). The highest crustacean density varies depend on the environment characteristic of the research station. The highest density was 1456 ind/m2 (station 6) and the lowest density was 27 ind/m2 (station 8). Diversity Index was lower category (H’ = 3.0700), while Similarity Index (E = 2.0180) was high enough, so the distribution of crustacean relatively similar. Dominancy Index was low (C = 1.6270). While the highest mangrove diversity Index was at Muara Ilu I (H = 2.14) and following by Muara Ilu II (H = 1.40) and Mauara Pantuan (H = 2.03). Over all the three locations of mangrove vegetation (tree, belta and seed) are in the lower categories diversity index, similarity index and dominance index. Keywords: crustacean, mangrove ecosystem, Mahakam delta, East Kalimantan, diversity, densit
STUDI KANDUNGAN LOGAM Pb DALAM BATANG DAN DAUN KANGKUNG (Ipomoea reptans) YANG DIREBUS DENGAN PENAMBAHAN NaCl DAN ASAM ASETAT
No full textStudy on The Contentof Pb in Twigs And Leaves of Kangkung (Ipomoea reptans Poir) Boiled With The Addition of NaCl And Acetic Acid. Kangkung is a kind of favorable vegetables that used to grow near a river, and is cultivated and watered with water from the river. If the river is polluted by heavy metals, there is a risk that the plant is contaminated too. A study on the content of Pb in kangkung planted in Pb contaminated media has been conducted, and it was proven that Pb was found in the plant. Land kangkung (Ipomoea reptans) was used as sample, and was planted in hydrophonic media, and watered with Multigrow Complete Plant Food (2000 mg/L) and Pb solution (2 mg/L) twice a day. Samples were taken based on the age of 54 days, then the twigs and leaves were boiled in different ways: I. Boiled with no addition, II. Boiled with addition of NaCl , and III. Boiled with addition of acetic acid. IV. Unboiled sample as the control. Inductively Coupled Plasma Spectrometer (ICPS) Fison 3410+ was used to measure the Pb content. It was shown that boiling the kangkung reduced the Pb content in the leaves as well as in the twigs; however, the acetic acid addition showed the least effect. In the leaves the three different ways of boiling did not show significant different, while in twigs the different was significant.Keywords: heavy metals, kangkung, lead contamination, contamination in vegetables, way of cookin
PENGARUH MUSIM TERHADAP PLANKTON DI PERAIRAN RIAU KEPULAUAN DAN SEKITARNYA
No full textSeasonal influenzed on plankton of the waters around Riau islands. The observation was conducted during April -May 2002. This study was done in relation with observation on environment quality of the waters around Riau Islands.The parameter observed were focus on the plankton communities for tweentyfives points of stations which were grouped into two zone based on the distance of the each station. Plankton abundance varied with location groups from 50- 90 % respectively. Community structure was dominated by the group of diatoms such as Chaetoceros, Dytilum, Nitzschia,Thalassionema, Thalassiothrix and the genus Ceratium (the group of Dinoflagellata). Community structure of zooplankton was dominated by the group of Copepods (45 – 90 %) and Polychaeta, Chaetognata, Bivalvia, Gastropods and Oikopleura (more than 90 %). The results describe the relationship between the water environmental condition and variation of plankton condition.Keywords: plankton, Riau Islands waters, seasonal influenz
SEBARAN DAN LUAS HUTAN MANGROVE DI WILAYAH PESISIR TELUK PISING UTARA PULAU KABAENA PROVINSI SULAWESI TENGGARA
No full textDistribution and area of mangrove forest in Pising Bay coastal area North Kabaena Island Southeast Sulawesi. Researched of mangrove forest in Pising Bay, North Kabaena Island Southeast Sulawesi was carried out on April 2006. Data digital Landsat 7ETM+ parth/raw 113/064 was used for mangrove mapping. Classification method was done is multispectral supervised with artificial neural networks algortms. Analysis and data validation from field survey, it is estimated that distribution and areas of mangrove forest in Pising Bay, North Kabaena Island Southeast Sulawesi is 152.128 Ha. Mangrove in Pising Bay dominated by rhizophora apiculata, rhizophora mucronata; and the forest is relatively in good condition. Keywords: Mangrove, Distribution, Pising Bay, Kabaena Islan
PENDETEKSIAN JENIS DAN KELAS AROMA DENGAN MENGGUNAKAN METODE ONE-VS-ONE DAN METODE ONE-VS-REST
No full textAroma classification using one-vs-one and one-vs-rest methods. Computational Intelligence used in patternclassification problem can be divided into two different parts, one based on Neural Network and the other based onStatistical Learning. The Statistical Learning discovered by Vapnik on 70-est decade. For the pattern classification, Vapnik developed hyperplane optimal separation, which is known as Support Vector Machines Method (SVM). In the beginning, SVM was designed only to solve binary classification problem, where data existing are classified into two classes. To classify data whose consist of more than two classes, the SVM method can not directly be used. There are several methods can be used to solve SVM multiclasses classification problem, they are One-vs-One Method and One-vs-Rest Method. Both of this methods are the extension of SVM binary classification, they will be discussed in this article so that we can see their performance in aroma classification process. Data of aroma used in this experiment is consisted of three classes of aroma, each of them has six classes. The division of this class is based on alcohol concentration mixed into each of those aromas. For example, for aroma A, there are six kinds of aroma A with different alcohol concentration: 0%, 15%, 25%, 30%, 45% and 75%. The performance of these methods is measured based on their ability to recognize and classify aroma, precisely and match with the right class or variety of data existed.Keywords: classification, kernel, svm, odo