Journal of Mathematical and Fundamental Sciences
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Efficient Alternative Method for Computing Multivariate Resultant Formation
Get PDFIn elimination theory, the matrix method of computing resultant remains the most popular due to its less computational complexity compared to Groebner basis and set characteristics approaches. However, for a matrix method to be effective, the size and the nature of elements of the matrix play an important role, since if the resultant is not an exact resultant, it has to be extracted from the determinant of the corresponding resultant matrix.. In this paper, a new resultant matrix is proposed. The proposed construction consists of four blocks, one of the blocks uses an entry formula of computing a Dixon matrix, while, two of the blocks use a mapping from the Jouanolou's method and the last block consists of only zero elements. The new formulation is computed without intermediate cancelling terms which reduces the complexity of the construction and enhances its effectiveness
Robusta Coffee (Coffeacanephora) Decreasing IL-1α (Interleukin-1α) Expression and Increasing the Number of Fibroblasts in Healing Process in Dental Pulp in Wistar Rats
Get PDFFibroblasts and IL-1α are important components of inflammation and healing in dental caries. This healing allegedly could be enhanced by robusta coffee. The aim of this study was to investigate the effect of varying concentrations of robusta coffee on IL-1α expression and the number of fibroblasts. Wistar rats were used, divided into 4 groups and 3 subgroups (7-, 14"‘, and 21-day rats) with each group containing 4 animals: Control group: untreated group; 25% Coffee Group: cavities + treated with 25% coffee bean paste; 50% Coffee Group: cavities + treated with 50% coffee bean paste; 75% Coffee Group: cavities + treated with 75% coffee bean paste. The 7-, 14-, and 21-day rats were sacrificed serially for analysis of the number of dental pulp fibroblasts by staining with HE and IL-1α expression by immunohistochemistry. The resulting data were analyzed descriptively and using ANOVA, followed by an LSD test. The higher the concentration of robusta coffee, the more the expression of IL-1α decreased and the more the number of fibroblasts increased. It is suspected that immunomodulatory proteins inhibit IL-1α expression. It was concluded that robusta coffee could decrease IL-1α expression and increase the number of fibroblasts during the healing process in the dental pulp of Wistar rats
Simulation and Fabrication of Double Barrier Structure of P-I-N Amorphous Silicon (a-Si) Device
No full textAbstract. The application of double barrier (DB) structure in p-i-n amorphous silicon (a-Si) device was studied. The theoretical study was done to obtain device parameters such as tunneling probability and current density. The tunneling probability was calculated by employing the Schroedinger equation, WKB approximation and Green function. Width of potential well, width and height of barrier were varied to obtain the highest tunneling probability value. The current density was contributed by diffusion, and tunneling current densities. It was found that current density had a peak of 3950 A/m2 at 0.56 volt forward bias. Furthermore, the fabrication of p-i-n a-Si device with double barrier structure was successfully carried out. To realize the double barrier structure, optimization of optical band gap of barrier a-SiC:H was done by varying ratio of CH4 to [CH4+SiH4]. The fabrication of p-i-n a-Si device was then done by using Plasma Enhanced Chemical Vapor Deposition (PECVD) technique with a structure of glass substrate/TCO/p-a-Si:H (2.15 eV;140Ã…)/i-a-Si:H (1.81 eV;1800 Ã…)/barrier a-SiC:H (2.36 eV;45 Ã…)/potential well i-a-Si:H (1/81 eV; 30 Ã…)/barrier a-SiC:H (2.36 eV; 45 Ã…)/n-a-Si:H (1.81 eV;180 Ã…)/Al. The I-V characteristic of the device showed a peak current calue at 0.55 forward bias. Simulasi dan Fabrikasi Struktur Double Barrier pada Divais Amorphous SiliconSari. Aplikasi struktur double barrier (DB) pada divais amorphous silicon (a-Si) telah dilakukan untuk memperoleh beberapa parameter divais seperti probabilitas tunneling dan rapat arus. Probabilitas tunneling dihitung dengan menerapkan persamaan Schroedinger, pendekatan WKB dan fungsi Green. Lebar sumur potensial, lebar dan tinggi barrier telah divariasikan untuk memperoleh harga probabilitas tunneling yang maksimum. Rapat arus total dari divais dalam perhitungan ini merupakan jumlah dari rapat arus difusi dan rapat arus tunneling. Diperoleh bahwa rapat arus total memiliki nilai maksimum sebesar 3950 A/m2 pada tegangan bias maju 0,56 volt. Selanjutnya, telah berhasil juga difabrikasi divais p-i-n a-Si dengan struktur double barrier. Didapatkan bahwa karakteristik I-V dari divais menunjukkan adanya puncak rapat arus pada tegangan bias maju 0,55 [email protected]
Epitaxy of GaN Film by Hydrogen Plasma Assisted MOCVD
Get PDFAbstract. We have studied the effect of hydrogen plasma on GaN film, grown by plasma-assisted metalorganic chemical vapor deposition (MOCVD). GaN films grown on a sapphire (0001) without the buffer layer have a polycrystalline structure. While films grown using the buffer layer tends to have a single crystal orientation. We have tried to increase the growth rate by varying the TMGa:N ratio. We found that the growth rate of the films were 450 nm/h with TMGa:N ratio of 1:600. However the films show a polycrystalline structure. Using hydrogen plasma during the growth, we have shown by XRD analysis that the films structure was highly oriented in (0002) plane parallel to substrate and the crystalline quality is improved. Epitaksi Film GaN dengan MOCVD Berbatuan Plasma HidrogenSari. Telah dipelajari efek dari plasma hydrogen pada film Gan, yang ditumbuhkan dengan MOCVD yang dibantu dengan plasma. Film GaN ditumbuhkan di atas safir (0001) tanpa bantuan lapisan penyangga mempunyai struktur polikristalin. Sedangkan film yang ditumbuhkan dengan bantuan lapisan penyangga mempunyai kecenderungan membentuk Kristal dengan orientasi tunggal. Telah dicoba untuk menaikkan kecepatan pertumbuhan Kristal dengan mengubah-ubah perbandingan TMGa:N. Telah diperoleh kecepatan pertumbuhannya menjadi 450nm/jam bila perbandingan tersebut 1:600, akan tetapi strukturnya memperlihatkan sifat polikristal. Dengan bantuan plasma hidrogen analisis XRD menunjukkan bahwa orientasi film sejajar dengan arah (0002) dan sifat kristalnya dapat diperbaiki
Study on the Making of Blended Cement by Mixing Granulated Blast Furnace Slag with Portland Cement Clinker
Get PDFAbstract. This paper presents the results of laboratory into the effect of slag fineness and slag composition added to portland cement clinker, to the compressive strength of the paste. The results showed that slag of 4260 cm2/gram fineness can be added up to 3O% to a portland cement clinker to increase compressive strength from 28 MPa to about 40 MPa. Scanning electron micrograph of the pastes showed that the inter granular voids between slag particles and sand particles were densely filled with line CaO-SiO2-H2O gel after 28 days observation, and in case clinker without slag, densification of CaO-SiO2-H2O gel still left pores even after 23 days of observation. The fineness of slag is more important than its composition in the blended cement. Studi Pembuatan Semen Campur (Blended Cement) dari Campuran Terak Tanur Tiup dan Klinker Semen PortlandSari. Paper ini menyajikan hasil percobaan laboratorium yang meneliti pengeruh kehalusan terak dan komposisi terak yang ditambahkan ke dalam klinker semen Portland. Hasil percobaan menunjukkan bahwa terak dengan kehalusan 4260 cm2/gram dapat ditambahkan ke dalam klinker sampai maksimum 30%, untuk meningkatkan kuat tekan dari semula 28 Mpa menjadi 40 Mpa. Foro SEM menunjukkan bahwa kekosongan antarbutir partikel terak dengan partikel pasir terisi dengan baik oleh pasta halus CaO-SiO2-H2O setelah pengamatan selama 28 hari. Untuk klinker tanpa terak, pasta masih mempunyai pori mesipun setelah 28 hari pengamatan. Kehalusan terak lebih penting daripada komposisinya di dalam semen campur
A Global Kam-Theorem: Monodromy in Near-Integrable Perturbations of Spherical Pendulum
Get PDFThe KAM Theory for the persistence of Lagrangean invariant tori in nearly integrable Hamiltonian systems is lobalized to bundles of invariant tori. This leads to globally well-defined conjugations between near-integrable systems and their integrable approximations, defined on nowhere dense sets of positive measure associated to Diophantine frequency vectors. These conjugations are Whitney smooth diffeomorphisms between the corresponding torus bundles. Thus the geometry of the integrable torus bundle is inherited by the near-integrable perturbation. This is of intereet in cases where these bundles are nontrivial. The paper deals with the spherical pendulum as a leading example
Structure and Thermal Property of Poly(R,S)-B-Hydroxybutyrate Synthesized by Aluminoxane Catalyst.
No full textAbstract. Poly(R,S)-B-hydroxybutyrate (PHB) was synthesized by ring-opening polymerization of racemic (R,S)-B-butyrolactone using tetraisobutyldialuminoxane (TIBAO) as catalyst. In previous studies, some factors or polymerization conditions such as polymerization suhue, polymerization time, nature of solvent, catalyst concentration, and modification of the catalyst system by water addition were varied to obtain optimal polymerization-results based on yield and molecular weight of polymers obtained. This study was emphasized on characterization of polymer by 13C NMR spectroscopy and Differential Scanning Calorimetry (DSC) to obtain informations about chemical structure and thermal properties of polymer obtained using tetraisobutyldialuminoxane catalyst. These analyses showed that tetraisobutyldialuminoxane catalyst produced partially stereoregular polymer depending on the quantity of water added to TIBAO catalyst. Extraction of polymer with acetyl-acetone (AcAc) or acetone separated the polymer into a soluble atactic fraction with amorphous structure and an insoluble isotactic fraction with crystalline structure. Addition of a certain quantity of water to the catalyst and treatment of polymer by solvent extraction have resulted in an increase in stereoregularity and crystallinity of polymer
Identifikasi Lapisan Batubara dari Segi Geokimia Anorganik
No full textSari. Penentuan kelimpahan unsur kimia dalam percontoh lapisan batubara dilakukan melalui analisis unsur kimia pada abu batubara berupa V, Ni, Cr, Co, Mo, Cu, Zn,Pb, Mn, Sn, Sr, Ba, Cd, As, Ag, Al, Ca, Mg, Fe, Na, dan K serta melalui fraksi-fraksi batubara hasil pemisahan sink and float berupa Si, Al, Ca, Mg, Fe, Ni, Cu, Na, dan K. Jenis unsur tersebut dapat menjadi parameter identifikasi lapisan yang berguna dalam korelasi stratigrafi lapisan, dan gambaran kecenderungan asosiasi mineral dengan golongan maseral batubara yang dapat mendukung pararameter tadi. Dari analisis principal component didapati bahwa Ni, Cr, dan V merupakan parameter yang baik untuk identifikasi lapisan; sebagai pembanding digunakan data lapisan batubara Bihar dari India dan Kanada. Unsur ini diperkirakan terikat pada molekul bahan organik sebelum diagenesis gambut, bersama terbentuknya kuarsa, kaolinit, gips dan cenderung berasosiasi dengan huminit/vitrinit. Mineral yang cenderung terbentuk selama diagenesis adalah siderit, kalsit, Mnkarbonat, serta illit/smektit yang lebih berasosiasi dengan inertinit. Coal Seam Identification from the Aspect of Inorganic GeochemistryAbstract. Elements abundance in the coal scams samples were determined by analyzing 1) the coal ash, namely V, Ni, Cr, Co, Mo, Cu, Zn, Pb, Mn, Sn, Sr, Ba, Cd, As, Ag, Al, Ca, Mg, Fe, Na, and K, and 2) maceral rich coal fractions by sink & float separation, namely Si, Al, Ca, Mg, Fe, Ni, Cu, Na, and K. The scope is to obtain certain elements as a parameter for coal scam identification which could be applied as a useful stratigraphic correlation tool and an inferrence on mineral occurence associated with maceral groups within the coal seam Ni, Cr, and V are shown to be the best parameter for seam identification by means of principal component analysis; for comparison purposes data from Bihar (India) and Canada were used. These elements are interpretated to be fixed to the organic molecules before peat diagenesis contemporancously with the formation of quartz, kaolinite, and gypsum and tend to associate with huminite/vitrinite. Minerals tend to be formed during diagenesis are siderite, calcite, carbonate of Mn, and illite/smectite with the associated inertinite
Teori Kendali Klasik Versus Prinsip Maksimum Pontryagin dalam Pembentukan Strategi Kendali Poros Tukik Satelit Siaran Langsung
No full textAbstract. This paper describes the development of pitch control strategy for space craft possessing a Direct Broadcasting Satellite configuration which is assumed to consist of a main rigid body plus large flexible solar arrays. The bias momentum concept of the double gimballed reaction wheel is applied for generating the pitch control torques. It is found that the wheel acceleration/deceleration produces an undesired cross coupling in roll, yaw, and pitch axis, In order to minimize this coupling, the pitch control strategy is then constructed based on the Pontryagin's Maximum principle. For comparison the classical second order theory is also applied. It can be shown that the application of maximum principle results in a better control strategy. Sari. Tulisan ini menyajikan perancangan strategi kendali poros tukik suatu wahana antariksa yang memiliki konfigurasi Satelit Siaran Langsung yang terdiri dari badan utama kaku dan panel surya lentur berukuran besar. Konsep pengubahan momentum roda reaksi dua engsel diterapkan untuk membangkitkan torsi kendali poros tukik. Dalam analisis di sini ditemukan kopling silang (cross coupling) pada ketiga poros olah gerak wahana. Untuk memperkecil kopling tersebut, strategi kendali poros tukik dibangun berdasarkan prinsip maksimum dari Pontryagin. Sebagai pembanding, teori kendali klasik orde dua juga diterapkan. Di sini dapat ditunjukkan kelebihan prinsip maksimum Pontryagin
Spektrofotodensitometri untuk Menentukan Antidepresan Amin Trisiklik yang Beredar di Indonesia dalam Tablet dan dalam Urin
Get PDFPenentuan kadar antidepresan amin trisiklik yang beredar di Indonesia (amitriptilin, nortriptilin, dan imipramin) dengan cara spektrofotodensitometri dilakukan terhadap tablet dan urin. Isolasi dari tablet dilakukan dengan methanol dan dari urin dengan eter. Cara ini sudah dicoba untuk menentukan kadar senyawa amin trisiklik dalam tablet dan urin sukarelawan setelah pemberian senyawa-senyawa ini dalam dosis tunggal. A spectrophotodensitometric method has been carried out for the determination of tricylic amine antidepressants available in lndonesia (amitriptyline, nortriptyline and imipramine) in tablets and urine. Isolation was done by methanol from tablets and by ether from urine. The method has been applied for examinations of tricyclic amine compounds in tablets as well as in urine of volunteers receiving a single dose of the compounds.