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STUDI EKSTRAKSI PELARUT EMAS (III) DALAM LARUTAN KONSENTRAT TEMBAGA PT FREEPORT DENGAN 8-METYLXANTIN
Full text linkSolvent extraction of Au (III) in Cu-concentrate solution at PT Freeport Indonesia by using 8-Methylxanthine had been carried out. Three steps of research consisted of Synthesis of 8-Methylxanthine as an extractant, Selectivity and Ability Test of gold extraction, and its application for the sample of Cu-concentrate. The result of synthesis showed that the extractant 8-Methylxanthine was a yellowish white crystal with m.p. 366 – 368 0C. The selectivity of Au (III) extraction on to Cu as well as Fe metal ions was very high. The extractant 8-Methylxanthine was able to isolate Au(III) in the Cu-concentrate and the structure of compound obtained was predicted to be two nuclei complex compound.Keywords : extraction, gold, Cu-Concentrate, methylxanthin
TELAAH TEORITIS BAK-ATOM QUANTUM DOT SEMIKONDUKTOR DALAM MEDAN MAGNET LUAR
Full text linkAnalytical calculation on the atomic-like phenomena is presented in a semiconductor quantum dot trapped by two-dimensional harmonic potential in the presence of a homogeneous magnetic field. The calculation neglects both Zeeman splitting and spin orbit interaction. This paper is proposed as the first sight of advanced research on nanotechnology in Indonesia. Many of the phenomena observed in atoms and nuclei are also observed in the semiconductor quantum dot which is then called an artificial atom. It has been shown that atomic shells can be described by a set of degenerated energy levels filled by 2, 6, 12, ... electrons known as “magic numbers”. The results of the calculations show that the Fock-Darwin spectrum will enter Landau regime when its cyclotron frequency (fc) is much larger than the frequency associated with the potential confinement (fo).
Keywords: Semiconductor quantum dot, Electron confinement, Shell structure, Artificial ato
KAJIAN POTENSI PANAS BUMI DAN REKOMENDASI PEMANFAATANNYA PADA DAERAH PROSPEK GUNUNGAPI UNGARAN JAWA TENGAH
Full text linkTelah dilakukan kajian tentang potensi energi panas bumi dan rekomendasi pemanfataanya di daerah prospek G. Ungaran, Jawa Tengah. Penelitian bertujuan untuk memperkirakan potensi panas bumi G. Ungaran, serta membuat skema pemanfaatan untuk digunakan sebagai dasar rekomendasi utilisasi potensi panas bumi di daerah tersebut.Penelitian yang dilakukan terdiri dari bidang-bidang geologi, geokimia, dan geofisika. Hasil penelitian menunjukkan bahwa daerah prospek panas bumi berada di lereng selatan G. Ungaran, yaitu di daerah Gedongsongo. Estimasi potensi energi panas bumi G. Ungaran dapat diperkirakan berdasarkan Metode Perbandingan. Berdasarkan hasil geothermometri gas G. Ungaran diperoleh suhu reservoir sebesar 230 0C, dengan daya per satuan luas diperkirakan sebesar 15 MWe/km2. Bila faktor konversi energi panas ke energi listrik sebesar 15%, maka besarnya daya listrik per satuan luas adalah 2,25 MWe/km2. Bila luas daerah prospek panas bumi G. Ungaran diperkirakan sebesar 5 km2, maka daya listrik yang dapat dimanfaatkan sebesar 11,25 MWe.Kata kunci : Panas bumi, Gunung api, Energ
ON The SM -Operators
Full text linkThis is a partial part of our results in studying generalization of Hilbert-Schmidt and Carleman operators in Banach spaces. This problem can be done if we preserve some intrinsic properties of Hilbert spaces involved; for examples, reflexivity and separability. The result of the generalization of Hilbert-Schmidt operator will be called SM-operator. Infact, almost all of properties of the SM-operator preserve almost all of properties of the Hilbert-Schmidt operators. The application on some classical Banach spaces will appear in the next publications.
Keywords: Orthonormal Schauder bases,separable and reflexive Banach spaces, Hilbert- Schmidt operato
ON FINITE CONVERGENCE INDEX
Full text linkChaatit, Mascioni, and Rosenthal defined the class of functions of finite Baire index and proved that the class forms an algebra and a lattice. Following that idea, in this paper we define ¹((fn)), the finite convergence index of a given sequence of real-valued functions (fn). Let (fn); (gn) be sequences of real-valued functions on a Polish space X and (hn) be any of the sequences (fn)+(gn), (fn):(gn), maxf(fn); (gn)g, minf(fn); (gn)g, then we prove that ¹((hn)) · ¹((fn)) + ¹((gn)).Key words and Phrases: finite convergence index, sequences of function
INHIBISI INSEKTISIDA KARBAMAT DAN ORGANOFOSFAT PADA ASETILKHOLINESTERASE LEBAH MADU
Full text linkIt is generally already accepted that organophosphate and carbamate insecticides function due to their ability to disrupt the transmission of impulses at certain synaptic junctions in the nervous system by inhibition of acetylcholinesterase. Type of inhibition reaction of carbamate (Baycarb and MIPC) and organophosphate (Dichlorvos and Monochrotophos) insecticides on honey-bee acetylcholinesterase (AChE) is shown in this investigation. For this study, the enzyme was produced by extraction of honey-bee heads using 0.01 M and pH 7.0 aqueous phosphate buffer solution, while N-methylindoxyl acetate (MIA) in absolute methanol at concentration of 0.005 g/mL was used as a substrate stock solution. Enzyme activity was detected using HPLC spectrofluorometer at 450 nm and 495 nm for excitation and emission wavelength, respectively. Based on detection of initial reaction rate between the enzyme with carbamate or organophosphate, it could be concluded that the reactions were competitive inhibition.Keywords: inhibition, acetylcholinesterase, carbamate, organophosphate
SYNTHESIS OF 4’-ALLYLBENZO-3N-CROWN-N ETHERS AND THEIR MASS SPECTRA COMPARED WITH BENZO-3N-CROWN-N ETHERS
Full text linkSynthesis of 4’allylbenzo-3n-crown-n ethers was carried out by reacting demethylated eugenol with α,ω-dichloro-oligoethylene glycols in 1-butanol under basic condition. The mass spectra of 4’allylbenzo-3n-crown-n and benzo-3n-crown-n were investigated by mass spectrometry using electron impact under 70 eV of electron bombardment as ionisation method. The difference between the group of compounds is only the present of allyl moiety as a side chain at the other side of benzene ring. The first group consisting of four compounds (n= 4,5,6 and 7) are the products of synthesis from eugenol precursor while the reference consist of three compounds (n= 4,5, and 6). The mass spectra of the first group show m/z = 176 as the base peak except 4’allylbenzo-12-crown-4 base peak is the molecular ion with m/z= 264. Peak of m/z = 176 has the structure of stable 1,4-dioxane-like . The presence of allyl group at position 4 of the benzene ring show significant effect to mass spectra pattern especially to 4’allylbenzo-12-crown-4. While the three compounds of the second group gave m/z= 136 as the base peak. This ion has similar structure as 1,4-dioxane-like mentioned earlier. In general it can be said that the mass pattern of the studied compounds come from the cleavage of the polyether rings according to M-nx44, where mass of 44 is C2H4O (ethylene oxide-like). The allyl side chain is more stable than the polyether rings under the investigated ionisation. The same case happened to eugenol as well as to safrol where the base peak is the molecular ion.Keywords: allyl-benzo-crown ethers, mass spectra, electron impact ionisatio
PENGENALAN GAMBAR RAMBU-RAMBU LALU-LINTAS DENGAN METODE KUANTISASI RERATA
Full text linkSalah satu ciri yang bisa dikembangkan dalam pengenalan gambar rambu-rambu lalu-lintas adalah ciri yang melibatkan content pada gambar, yang meliputi ciri dasar gambar seperti warna, bentuk dan tekstur. Pada gambar rambu-rambu lalu lintas, ciri bentuk merupakan ciri dominan yang mengisi content gambar. Untuk mendapatkan ciri bentuk ini ada berbagai macam metode yang banyak digunakan antara lain deteksi tepi, transformasi fourier, integral proyeksi dan kuantisasi. Dalam penelitian ini memanfaatkan ciri bentuk dengan menggunakan teknik kuantisasi untuk menyajikan ciri dari gambar rambu-rambu lalu lintas, yaitu kuantisasi rata-rata. Proses pengenalan dilakukan dengan menggunakan template matching antara vektor gambar rambu-rambu yang dimasukan (vektor query) dengan semua tanda rambu-rambu yang ada dalam database (vektor template). Dengan ukuran vektor yang kecil diharapkan proses template matching ini dapat dilakukan dengan cepat. Dalam hal ini yang dicari adalah nilai selisih terkecil dari vektor query dan vektor template yang ada dalam database. Berdasarkan hasil percobaan yang telah dilakukan, bertambahnya ukuran sampling menghasilkan performansi yang semakin kecil atau prosentase error yang semakin besar, kondisi ini dikarenakan banyak ciri bentuk pada gambar yang hilang, sehingga pengenalan terhadap gambar menimbulkan error yang besar. Hasil percobaan yang cukup baik pada saat ukuran sampling (segmen) 4x4, didapatkan prosentase error rata-rata sebesar 9.19% (jumlah gambar salah sekitar 3 gambar) dengan performansi sebesar 90.81.
Kata Kunci: Rambu-rambu lalu-lintas, kuantisasi rata-rata, template matchin
EVALUASI KESESUAIAN LAHAN UNTUK BUDIDAYA TANAMAN PANGAN MENGGUNAKAN JARINGAN SYARAF TIRUAN
Full text linkPenentuan jenis tanaman pangan yang sesuai ditanam pada lahan tertentu berdasarkan nilai-nilai karakteristik lahan sangat diperlukan sebagai pendukung pengambilan keputusan, koordinasi, dan pengendalian bagi para peneliti, praktisi, dan perencana penggunaan lahan, sehingga kerugian (finansial) yang cukup besar tidak terjadi nantinya. Program komputer dengan menggunakan Jaringan Syaraf Tiruan (JST) metode Learning Vector Quantization (LVQ) dapat digunakan sebagai alat yang tepat dalam memberikan informasi tanaman yang cocok ditanam dengan mudah, cepat, dan akurat. Data pelatihan didapat dari kombinasi nilai karakteristik lahan yang termasuk dalam kelas kesesuaian S1 dan S2. Hasil pengujian menunjukkan bahwa nilai Eps (error minimum yang diharapkan) = 0.005, nilai ( = 0.05, nilai maksimum epoh = 10, dan nilai pengurangan learning rate sebesar 0.1*( merupakan nilai-nilai yang cukup efektif dan efisien dalam melakukan prediksi jenis tanaman pangan yang sesuai ditanam pada lahan tertentu karena tingkat ketepatan prediksinya adalah 100% dari 22 data pengujian.
Kata Kunci: Jaringan syaraf tiruan, learning vector quantization, evaluasi kesesuaian laha