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PENAKSIR RASIO DAN PENAKSIR REGRESI YANG EFISIEN UNTUK RATA-RATA POPULASI PADA SAMPLING ACAK SEDERHANA MENGGUNAKAN DEVIASI KUARTIL DAN KOEFISIEN SKEWNESS Linda Veronika; Sigit Sugiarto; Rustam Efendi
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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In this article the combination of ratio estimators and ratio-regression in simple random sampling using quartile deviation and coefficient of skewness are discussed, which is a review from the article Jeelani et.al. [International Journal of Modern Mathematical Sciences, 6(3): 174-183]. These estimators are biased estimators and their mean square errors are determined. Estimator with the smallest mean square error is the most efficient estimator. A numerical example is given at the end of discussion.

METODE NEWTON-STEFFENSEN DENGAN ORDE KEKONVERGENAN TIGA UNTUK MENYELESAIKAN PERSAMAAN NONLINEAR Fitriani '; Johannes Kho; Supriadi Putra
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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This article discusses Newton-Steffensen method to solve a nonlinear equation. The method is obtained by combining Newton's method with Steffensen's method. The proposed method has third order convergence. Computational examples illustrate that the discussed method is better than Newton method and Steffensen method in terms of obtaining the root for same initial guesses.

DERAJAT VERTEKS GRAF TERHADAP HIMPUNAN VERTEKS Fauziah Arani; Rolan Pane; Endang Lily
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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This article discusses methods to define the degrees of the graph vertex. These methods include union, intersection, and difference symmetric from vertex set. Based on this definition the relation between the degrees of the graph vertex and vertexset is obtained. An example is given to illustrate the implementation of the methods.

CADANGAN PROSPEKTIF ASURANSI JIWA BERJANGKA DENGAN HUKUM DE MOIVRE Dini Ramadani; Johannes Kho; Aziskhan '
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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This article discusses the calculation of the prospective reserve for term life insurance with De Moivre’s law to someone with the age of x where the money will be paid only if the insurance client dies within the term of protection. Based on the calculation, this prospective reserve is influenced by single premium, present value of annuity due, and annual premium, for which the calculation is done using De Moivre’s law.

ANALISA PENGGUNAAN LENSA SILINDER UNTUK MENGUBAH BENTUK BERKAS LASER DIODA MENJADI BENTUK GARIS Muhammad Mashuri; Minarni '; Sugianto '
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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A research on the application of cylindrical lenses to change beam shape of diode lasers from eliptical to line shape has been conducted. The beam characteristic of the lasers before and after using the lenses were analyzed by a calibrated photodiode and a CCD camera. The distance between CCD camera and the lenses were also varied to obtain the optimal length of the line. The diode lasers used were λ=830 nm Coherent diode laser with beam size 0,6 mm and 0,9 mm in x and y axis and λ=638 nm Aixiz diode laser with beam size 1,2 mm and 1,6 mm in x and y axis were used. Three cylindrical lenses with three different focal length were used whice were 50 mm, 75 mm, and 95 mm respectively. The results showed that the maximum line lengths (L) of λ=830 nm diode laser were 1,86 mm, 2,55 mm, and 1,39 mm respectively. For the λ=638 nm diode laser the maximum line length (L) were 3,74 mm, 4,32 mm, and 3,87 mm respectively to the same focal length. The result also showed that the bigger λ produced the shorter line (L) than the smaller λ. For the biggest focus need the longest distance (z) to produce the longest line.

EFEK VARIASI WAKTU BALL MILLING TERHADAP KARAKTERISTIK ELEKTROKIMIA SEL SUPERKAPASITOR BERBASIS KARBON Fitria Puspita Sari; Erman Taer; Sugianto '
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Supercapacitor electrodes from rubber wood saw dust (RWSD) have been fabricated using experiment method to study the ball milling variation time on performance of the supercapacitor cells. The carbon electrodes were prepared with time variation of 20, 40, and 80 hours and thickness of 0.2 mm. Carbon electrodes were carbonized at 600oC and followed by physical activation method in CO2 gas atmosphere on the constant temperature of 900o C, and chemical activation was performed by KOH as an activating agent. Densities of the electrodes were 0.849 g/cm3 , 0.892 g/cm3 , 0.982 g/cm3 respectively. XRD measurement showed the peaks of carbon electrodes at 2θ of 24.091o and 44.473o which represented the presence of carbon materials with their crystal orientation of (002) and (100). SEM micrograph on magnification of 1000X showed that the pore distribution of the carbon electrodes dominant on macropores. This study found that the effects of increasing of ball milling time influenced the electrochemical properties of supercapacitor electrodes fro m RWSD. The optimum supercapacitor performance was found on 20 hour milling time electrode and had a specific capacitance of 55.414 F/g.

SISTEM OPTIK INTERFEROMETER MICHELSON MENGGUNAKAN DUA SUMBER LASER UNTUK MEMPEROLEH POLA FRINJI Yayuk Widamarti; Minarni '; Maksi Ginting
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Wavemeter could be built using an interferometer with two laser sources. In this study, Michelson interferometer was built using two lasers which were He-Ne laser and diode laser. Characteristics of its fringe pattern were analyzed based on the laser power and beam size. The results showed that fringe pattern for laser He-Ne was obtained at arm length 12.5 cm x 12.5 cm with the beam height from optical table of 11.7 cm. He-Ne laser used was 632.8 nm in wavelength with the 5 mW power made by Meredith instrument. The diode laser had wavelength 650 nm with the power of 5 mW made byRoithner. The output of He-Ne laser from the interferometer system had 0.3 mW, diode laser by 0.5 mW. The best fringe pattern for both lasers was with visibilities rangedfrom 0.63 and 0.098, and beam width of each laser of 4.11 mm for He-Ne laser and 4.30 mm x 4.26 mm for diode laser.

PENGARUH AKTIVASI KARBON DIOKSIDA PADA PRODUKSI KARBON AKTIF MONOLIT DARI KAYU KARET Herniyanti, Septa; Taer, Erman; ', Sugianto
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Activated carbon monoliths from rubber wood have successfully been fabricated using combined physical-chemical activation and chemical activation. The process of combination of physical-chemical activation was started from physical activation process by flowing CO2gas for 2 hours at temperature of 800 oC, then applying chemical activation process by immersing the carbon in 3 M KOH solution and 2,5 M H3PO4 solution. The samples activated by the combination of physical-chemical activation were named as A1and those that were activated by chemical activation were named as sample A2. Both activation methods yielded different activated carbon. The physical properties analyzed were density, porosity, and BET surface area, whereas the electrochemical property obtained from measurements using cyclic voltammogram method was specific capacitance. N2adsorption-desorption gas treatment resulted BET surface area of 542.586 m2g-1 and 115.147 m2g -1 for each sample, respectively. The resulted specific capacitances of the measurement using the cyclic voltammogram method for each sample were 43.67 F g-1and 37.74 F g-1 , respectively. Based on all obtained data analysis, it can be concluded that the physical-chemical activation produced larger BET surface area and higher specific capacitance than those resulted from chemical activation for supercapacitor cells.

PENGARUH MAGNETIK Fe3O4 PADA SERBUK KARBON TERHADAP TINGKAT PENYERAPAN LIMBAH LOGAM Fe Nur Akmal; Erman Taer; Sugianto '
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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The study on synthesis and characterization of magnetic carbon from mixture of rubber wood sawdust and for heavy metal of Fe absorption on the Siak river water samples has been done. The process of milling and seaving resulted a smallcarbon particle size of 38 μm, the increase in surface area of the carbon has beenachieved by chemical activation using the KOH Activator with weight ratio of carbonpowder of 4: 1. After that, carbon powder that had been activated was mixed to by comparison of 5: 4. The mixing process was done using a mortar and continued toballmiling process for 2 hours. Finally, a mixture of carbon powder and was carbonized at temperature of 850oC in N2 gas and then proceed to washing and drying proceses in order to produce carbon magnetic . Absorption testing of heavy metal of Fe in Siak river water samples was performed with variations in immersing time of ½ hours, 1 hour, and 2 hours. Atomic absorption spectroscopy test results revealed that absorption after 2 hours increased from 34,17% (without to 39,63% (using magnetic . Characterization of x-ray diffraction showed the peak of Fe at 2θ = 46,28o and scanning electron microscopy showed uniform particle size with irregular shape and whitish color. Results of Dispersive X-Ray Energy (DXE) proved the existence of metal Fe in magnetic carbon absorbent material from rubber wood sawdust.

SISTEM PEMANFAATAN ENERGI SURYA UNTUK PEMANAS AIR DENGAN MENGGUNAKAN KOLEKTOR PALUNGAN Fatmawati '; Maksi Ginting; Walfred Tambunan
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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A research has been conducted on Solar Energy Utilization System for Water Heater using Trough Collector. This research was carried out using an experimental method by putting in place an opened trough collector that exposed to sunlight. The highest temperature of collector produced was 50,03°C in average with an average temperature of water in the tank was 40,07°C at 1 PM, while the lowest temperature of collector was 39,14°C in average with an average temperature of water in the tank was 35,28°C at 10 AM. The highest temperature of collector occured at 1 PM, because the intensity of solar radiation at the time reached the maximum value. The experimental results showed that the higher the intensity of solar radiation, the higher the temperature of the water produced. The temperature of collector was also influenced by loss heat of the collector conduction. The highest loss heat by conduction was 29,05 W at 1 PM, while the lowest loss heat by conduction was 16,85 W at 10 AM.

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Journal Mail Official
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Riau

INDONESIA