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Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam
Published by Universitas Riau
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Mathematics
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Articles 424 Documents
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PEMANFAATAN LIMBAH PADAT TANDAN KOSONG KELAPA SAWIT DAN TANAMAN PAKIS-PAKISAN UNTUK PRODUKSI KOMPOS MENGGUNAKAN AKTIVATOR EM-4 Rudi Rahmadi; Amir Awaluddin; Itnawita '
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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Abstract

The composting process using  oil palm solid wastes (EFB),  palm oil mill effluent (POME), fern tree using effective microorganism 4 (EM 4) has been  conducted and this would facilitate  reduction of  the wastes from palm oil industry. The aim of this research was to find the best formulation using oil palm wastes, ferns, and EM 4 in producing a composted  material. The quality of compost was determined according toits pH, water content and C/N ratio at each 5 days for 30 days composting period. The water content of sample was determined using Gravimetri methode, while total-N was analyzed by Kjeldahl methode. The result indicated  that  co-composting of EFB andferns  using POME and EM-4 as the activators didn’t have  significance difference compared with that of  the composting products with the value of P>0,05. The value of pH, water and C/N ratio of composting products were respectively 7-8, 40-60% and 1314, following 30 days composting period.
PEMANFAATAN SELULOSA POPOK BAYI SEBAGAI SUBSTRAT UNTUK PRODUKSI ENZIM SELULASE OLEH ISOLAT BAKTERI S-16 DAN S-22 STRAIN LOKAL RIAU Dahlena, Maya; Dahliaty, Andi; Sy, Silvera Devi
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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Abstract

The S-16 and S-22 cellulolytic bacteria isolated from Siak River water were used in this study to produce cellulase with disposable diapers as a substrate. Cotton is the main component in the disposable diapers that can be used as a substrate in the production of cellulase. Cellulase is an enzyme that catalyzes the hidrolisis of β-1-4-glycosidic bond of cellulose. Fermentation was carried out for 10, 20, and 30 days by S-16 and S-22. Enzyme activity was determined using Nelson-Somogyi method. The results showed that the highest enzyme activity obtained at 20 days, with S-16 of (2,654 ± 0,53)x 10 U/mL and S-22 of (13,704 ± 4,91)x 10-3 U/mL.
PERBANDINGAN ISOLASI MINYAK ATSIRI BIJI PALA (Myristica fragrans Houtt) CARA HIDRODISTILASI MICROWAVE DAN KONVENSIONAL SERTA UJI AKTIVITAS ANTIBAKTERI DAN ANTIOKSIDAN Rachmi, Widya; Zamri, Adel
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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Abstract

Essential oil of nutmeg (Myristica fragrans Houtt) has been successfully obtained by distillation using conventional and microwave hydrodistillation methods. The essential oil produced by microwave method is more advantageous in yield of oil andcomponents of resulted compounds. The yield of extracted essential oil using microwave method is about 7,07% for 60 minutes higher than that of conventional method which is about 4,30% for 4 hours. Based on the result of  GC-MS analysis,microwave hydrodistillation components obtained 55 compounds more than conventional hydrodistillation as many as 43 compounds in essential oil. The results of antibacterial and antioxidant activity showed that essential oil could inhibit Bacillussubtilis of bacteria and had weak antioxidant activity than of ascorbic acid againtsDPPH radical that is >1000 ug/mL.
ISOLASI BAKTERI SELULOLITIK DARI PERAIRAN DUMAI Waidil Anuar; Andi Dahliaty; Christine Jose
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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Abstract

Dumai water samples are estimated to contain cellulolytic microorganisms because of farm waste. Samples 930 from Sei Pakning and 931 from Rupat Strait were water samples containing cellulolytic bacteria taken from Dumai. In this study the production of cellulase enzymes from cellulolytic bacteria in samples of 930 and 931 used CMC as a substrate. Cellulase is an enzyme that catalyses the hidrolisis of β-1-4-glycosidic bond of cellulose. All of the isolates produced cellulase and were able to degrade cellulose. The results indicated that 1% substrate gave the highest activity of Cellulase in the 931-4A (Rupat strait) (1.186 ± 0.319) x 10 -3 U/mL, whereas the highest specific enzyme activity of the bacterial isolates was 930-1C (8.438 ± 0.109) x 10 -3 U/mg.
PERBAIKAN ATURAN KUADRATUR NEWTON-COTES TERTUTUP Dina Oktavieny; Bustami '; Imran M.
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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Abstract

This paper discusses the improvement of closed Newton-Cotes quadrature rules. The idea is based on deriving weights of closed Newton-Cotes quadrature rules having the same length of intervals using degree of accuracy. By including the lower limit of the integral and the width of the interval as the two new additional variables,we obtain weights, the lower limit and the width of the interval used to form the improvement of closed Newton-Cotes quadrature rules. Computational tests using examples show that the accuracy of improvement formula is better than closed Newton-Cotes quadrature rules.
PERHITUNGAN VALUE AT RISK PORTOFOLIO SAHAM MENGGUNAKAN METODE SIMULASI MONTE CARLO Adilla Chandra; Johannes Kho; Musraini M
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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Abstract

This article discusses the calculation of Value at Risk (VaR) for stock portfolio usingMonte Carlo simulation. The standard deviation of return data of multiple stock andportfolio are normally distributed and used in the calculation of VaR. Monte Carlomethod is applied to simulate a new return value of stock and portfolio by generating arandom numbers based on the characteristics of the data, which is then used to estimatea VaR. The calculation of VaR at portfolio uses two assets which are Semen Indonesia (Persero) Tbk (SMGR.JK) and PT. Unilever Indonesia Tbk (UNVR.JK).
PENAKSIR RASIO REGRESI LINEAR SEDERHANA UNTUK RATA-RATA POPULASI MENGGUNAKANKARAKTER TAMBAHAN Astari Rahmadita; Harison '; Haposan Sirait
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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Abstract

Estimators discussed here are three regression ratio estimators of population mean Y using information on two auxiliary variables Xdan Z under simple random sampling without replacement. They are proposed bySingh, Upadhyaya and Premchandra [4] which is a review of the article “An Improved Version of Regression Ratio Estimator with Two Auxiliary Variables in Sample Surveys.” All estimatorsare biased. The efficient estimator is one with the smallest Mean Square Error (MSE), determined by comparing each type of estimator.
PERLUASAN METODE NEWTON DENGAN PENDEKATAN PARABOLIK Rahman, Abdul; Putra, Supriadi; ', Bustami
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 extension of Newton’s method derived from the Taylor expansion, where the curve is approached by a tangent line of the parabola. Analytically, it is shown that the iterative method has the cubic order of convergence, so it is more effective than the Newton’s method. Furthermore, computational results show that the iterative method is superior to the comparison methods in term of the number of iterations to obtain the estimated roots.
METODE KUADRAT TERKECIL BERBOBOT DAN APLIKASINYA PADA MODEL MATEMATIKA KONSUMSI BENSIN Riris Siagian; Imran M.; 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 the application of the least squares and weighted least squares method to determine the amount of fuel consumption at a given distance in the use of vehicles in and out of town at the same time using mathematical models. This articleis a review of Izzo’s article [Mathematics Magazine 73(3):226-231]. Computational examples using real data show that the solution given by the weighted least squares method to a mathematical model of gasoline consumption more in line with the real situation.
KONSTRUKSI SEDERHANA METODE ITERASI BARU ORDE TIGA Dedi Mangampu Tua; Syamsudhuha '; Asmara Karma
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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Abstract

We discuss two modications of Newton's methods for solving a nonlinear equation, constructed from two known third-order iterative methods. Our approach is to approximate a derivative from the improvement of the two known third-order iterative methods. Analytically it is shown that each modication of Newton's methodhas third order of convergence, and it requires three function evaluations per iteration. Therefore, its eciency index is 1:414, which is the same as Newton's method. Numerical examples show both methods are competitive with known third-order methods.

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