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Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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ANALISA PENGARUH VEGETASI TERHADAP TINGKAT KEBISINGAN DI SEPANJANG JALAN RAYA PEKANBARU-BANGKINANG

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Abstract

The influence of vegetation such as ketapang, sengon, mango, of acacia, durian andpalm along Pekanbaru-Bangkinang highway against noise level has been studied. Noisesource was originated from sound of vehicles passing through the highway. An instrument used to record the noise level in the study is Sound Level Meter (SLM). In order to obtain the absoption of noise level, then it was used 2 SLMs. The first SLMwas utilized to record the noise directly generated by vehicles without any obstaclesand the second SLM was located behind the trees as sound obstacles. The position ofthose two SLMs was arranged along the road with the distance of about 15 m from thehighway. The next measurement was to record the noise level for one day started from7: 00 a.m until 6: 00 p.m along the highway. The influence of the distance against thenoise level was also studied. The result of this research showed that palm trees has thehighest effect on noise reduction and followed by acacia, mango, durian, sengon andketapang trees. The high absorption of sound by palm tree of about 6.092% because the volume of the palm leaves per percentage of the absorption is smaller compared tothose for other vegetations. These results were compared to those of Maekawa andISO9613 calculation. From the comparison, it was obtained that Maekawa calculation ishigher compared to those of this research, while the ISO9613 calculation was lower.The error percentage of the calculation for Maekawa and ISO9613 was 6.82% and8.76% respectively. The profile of one day noise along the highway as a function of time showed that there were two peaks of noise that were occurred at 09.00-10.00 and17.00-18.00. Moreover, the noise level was reduced very significantly from 71.90dB(A) to 63.58 dB(A) as the measurement away from the noise source.

PENGUKURAN TINGKAT PENYERAPAN BUNYI KEPINGAN BATANG KELAPA SAWIT DENGAN MENGGUNAKAN TABUNG IMPEDANSI

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 1 (2014): Wisuda Februari 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Abstract

Research on measuring of levels of sound absorption by a piece of palm trunk wasdone. Sample of palm trunk used in this study was 22 years old and made intorectangular pieces with a size of 23 x 23 cm. The thickness of the samples was varied,namely 6mm, 9mm, 15mm. The source of sound used was generated from sweepfunction generator. The sound intensity inside the impedance tube before and afterpenetrating the sample was recorded using sound level meter. The sound frequencyrange used in this research was 100 Hz - 1000 Hz. The results indicated that in general,the sound intensity increases with the increase of sound frequency. However, theintensity of the sound was reduced very significantly after penetrating the sample insidethe tube. For high frequency, namely 1000 Hz then the percentage of sound absorbtionby a piece of trunk palm with the thickness of 6 mm, 9 mm and 15 mm was 3.4 %, 5.7% and 14 % respectively, while, for low frequency, namely 100 Hz, then the percentageof sound absorbtion by the material with the thickness of 6 mm, 9 mm and 15 mm was5.6 %, 8.3 % and 12 % respectively

ANALISA PENGARUH INTI KOIL TERHADAP MEDAN MAGNETIK DAN MUATAN PADA KAPASITOR DALAM RANGKAIAN SERI LC

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Magnetic field that produced by coils changes its value significantly when the coil core made from air replaced by ferromagnetic (Fe), paramagnetic (Cu) and diamagnetic (Al) materials. In this research the value of magnetic field was measured as a function of coil’s turns (N), applied current (I) and the distance from the center of the coil as the coil’s core changed from air to Fe, Cu and Al. Number of turns of the coils was varied namely 50, 100, and 150 with the length of 4.2 cm and diameter of 3.2 cm. Next, the coil and a capacitor were connected with a series circuit in which the value of the capacitance of the capacitor was 4700 μƒ. Magnetic field that produced by the coils were measured using Pasco magnetic probe PS-2162.While the voltage were measured using volt meter. From the result of the research it was found that the average value of magnetic field (N = 50 turns) for constant current of (2A) increased by 127% and 13.59 % when the core coil (air) was replaced by iron and copper respectively. While for aluminum, the value of the magnetic field was reduced by 45.56 % from air core. Theoretically, the value of charges on the capacitor and current flow in the circuit as a function of time oscillated in the form of sinusoidal. The charges on the capacitor at t=0 had its maximum value that was 9.4 x 10-4 Coulomb, The current in the circuit reached its maximum value that was 5.08 Ampere at t = 10 s.

PENENTUAN TINGKAT KEBISINGAN SEPEDA MOTOR KNALPOT STANDAR DAN MODIFIKASI

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 noise level produced by standard and modified motorcycles exhaust has been investigated. In this research, there were three types of motorcycles used namely Honda, Suzuki and Yamaha. Noise levels that generated by those motorcycles were measured using Sound Level Meter (SLM) SL 4112. In order to eliminate noise from other sources 5 different  angles (0o, 45o, 90o, 135o, and 180o) were used, then the measurement of noise from the motorcycles exhaust was done 2m from the exhaust. The results of the measurement showed that sound intensity generated by  standard motorcycle exhaust at angle of 90o produced maximum value of 78,17 dB, 79,62 dB and 97,55 dB for Honda, Suzuki and Yamaha respectively. By modifiying the exhaust, the noise level produced of Honda, Suzuki and Yamaha were 97,48 dB, 97,62 dB and 97,55 dB respectively. The significant increase  of noise level for modified exhaust with muffler was caused by several factors such as muffler and diameter of exhaust. The range value of noise level for the standard exhaust was measured at the angle of 90oand the engine variation of 5000 rpm was 78,66 dB while for the modified exhaust produced an average value of 97,55 dB with the same position and engine variation.

ANALISA PENGARUH KETEBALAN LEMPENGAN BESI (Fe) TERHADAP INDUKSI MAGNETIK YANG DITIMBULKAN OLEH BEBERAPA MEREK TELEPON SELULER

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Nowadays, a cellular telephone is predicted to generate the effect of electromagnetic radiation on the users. In this research, the measurement of magnetic induction generated by three cellular telephones (sample A, B and C) was demostrated. The measurement was performed in two directions namely horizontal and vertical directions. In order to measure the magnetic induction, was used a Pasco magnetic probe 2162. The magnetic induction in the horizontal direction was measured with the distance of 0,5 cm from the cellular telephone. The effect of a slab of iron with various thicknesses namely 1-4 mm on magnetic induction was also studied. The results of this research showed that the value of magnetic induction generated by the cellular telephone sample A is the highest among brand B and C with the value of 7.73300x10-4 Tesla and followed by sample B and C with the value of 3.6241x10-4 Tesla and 1.41615x10-4 Tesla respectively. The value of magnetic induction in vertical direction decreases very significantly with the distance. Moreover, the magnetic induction increases when a slab of iron with the thickness of 1 mm to 4 mm was introduced.

PENGUKURAN TINGKAT KEBISINGAN DI JALAN RAYA PEKANBARU-BANGKINANG SEBELUM DI BANGUN BEBAS HAMBATAN (HIGHWAY)

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Measurement of the noise level in the roadway of Pekanbaru-Bangkinang before building of Highway has been done. The sources of noise originated from the sound of vehicles that passed through the roadway. The level of noise has been measured by using a Sound Level Meter (SLM). The measurement of noise level carried out in two locations, first location was on roadway of Pekanbaru-Bangkinang KM 21 and the second location was at round aboard of Jalan Garuda Sakti and Jalan PekanbaruBangkinang. The noise level at first location was measured as a function of time from 07.00 until 18.00 pm during one week. In this research, the number of vehicles that passed through the first location have been counted every hour. Furthermore, the noise level was measured as a function of distance from the noise source using two SLMs, namely SLM type MS 6701 and SL 4112. The results showed that the noise level at the first location occurred on Saturday and Sunday at 16.00 to 18.00 with the highest value of 79.09 dBA and 78.28 dBA respectively, while the lowest noise value occurred on Friday at 12.00 to 13.00 pm with the value of 67.97 dBA. The highest noise level at the second location occurred at 17.00 to 18.00 with a value of 81.60 dBA. The value of noise level at the second location was higher compared to that of the first location. This was due to more number of vehicles that passed through that location compared to that of the first location. The profile of noise level occurred on Saturday was compared to that of the theoretical calculations. The result showed that both results had a similar characteristics. Moreover, the results of this research showed that the level of noise as a function of distance from the noise source was decrease with increasing the distance. The decrease of the noise level was caused by the absorption of the noise by the surrounding parameters such as air,vegetation and buildings nearby.

PENENTUAN DISTRIBUSI INDUKSI MAGNETIK YANG DITIMBULKAN OLEH BERBAGAI JENIS TELEPON SELULER DENGAN MENGGUNAKAN PROBE MAGNETIK PASCO

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 distribution of induced magnetic field due to various kinds of cellular telephone has been investigated. The induced  magnetic  field was measured using  Magnetic  Probe Pasco in two directions  namely  horizontal  dan  vertical. In horizontal direction the induced  magnetic  field  was  measured  with the distance of 0,5 cm above the cellular telephone.  The result showed that the  widest  distribution of  magnetic  field  was generated by Sony Ericcson cellular telephone, while Samsung cellular  telephone generated the narrowest value of induced  magnetic  field.  Moreover,  the highest and lowest  value    induced  magnetic  field  were  generated  by Sony Ericcson and Sony were 2,4x10-3Tesla and 1,2x10-3Tesla respectively. In  vertical  direction,  the induced magnetic  field was reduced significantly  the  as measured  away from the cellular telephone. The value of magnetization  was  highest from Samsung cellular telephone and  the  lowest from Blackberry. The value of magnetization from Samsung and Blackberry was 9,26x10-5emu/cm3 and 7,16x10-5emu/cm3 , respectively.

ANALISIS SPEKTRUM SUARA MANUSIA BERDASARKAN JENIS KELAMIN (GENDER) DAN KELOMPOK UMUR MENGGUNAKAN KOMPUTER

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Research on analysis of human voice spectrum based on gender and age group has been conducted. To record the human voice, it was used a microphone and a computer equipped with a software  called “Praat” as a substitute for spectrum analyzer. From the voice spectra, it was obtained the fundamental frequency (pitch) and formant. The sample of the human voice was recorded based on the male and women  voice which divided  into age group  such as  children aged 8-11 years, adult 19-23 years and elderly aged above 50 years. In this research, it was used 3 pieces of said, namely “Universitas Riau”, “Selamat Datang” and “Mari Berjuang”. The result of this research indicated that pitch of male was lower than that of women. In general,  the relationship between pitch and age showed that the pitch decreases as the age increases.  For male, the pitch decreases very significantly from 245,8 Hz to 124,6 Hz as the age increases from children to elderly, while for women the decrease of pitch was linear with small slope. The average formant value for boys is a little bit higher than that of girls which is 525 Hz and 512 Hz respectively. In general, the value of first formant (F1) decreases as the age of human increases.

PENGARUH KETEBALAN BAHAN ALUMINIUM TERHADAP INDUKSI MAGNETIK YANG DITIMBULKAN OLEH TELEPON SELULER

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Nowadays, a cellular phone is an important communication tool therefore, biologically the electromagnetic radiation produced from the cellular phone on the users become relevant. The measurement of magnetic induction generated by three brands namely A, B and C of cellular phone was carried out. The measurement was done for two directions such as horizontal and vertical direction. In order to investigate the effect of alumunium thickness on magnetic induction, several slabs of alumunium with the thichness of 1 mm – 4 mm were prepared. An instrument used for measuring the magnetic induction was magnetic sensors Pasco 2162. The magnetic induction was measured in horizontal direction at a distance of 0,5 cm from cellular phone with and without using an aluminium slab. The results showed that the magnetic induction in horizontal direction generated by cellular phone brand A is highest among A, B and C with the value of 1,09x10-4 Tesla, 1,07x10-4 Tesla, 9,75x10-5 Tesla respectively. The value of magnetic induction generated by a cellular phone reduces when a slab of alumunium was inserted between cellular phone and sensor. The measurement of the magnetic induction in a vertical direction shows that the further distance of the sensor to the cellular phones and the smaller the magnetic induction observed. The result also showed that the value of magnetic dipole moment of cellular phone based on the plot of magnetic induction versus distance is 1 Am2.

DESAIN PEMBUATAN DAN UJI COBA KUMPARAN HELMHOLTZ BERBENTUK LINGKARAN

Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Design and study  of Helmholtz coils have been carried out.  The coils  diameter was designed of about    13 cm and  number of turns of    50, 100, 150, 200 and 250. Magnetic field that produced by those coils was measured using  pasco  magnetic probe PS-2162 as a function of an applied current, distances and number of turns. As comparison,  then the magnetic field produced by these coils had been compared to the standard one.  Maximum value of magnetic field was obtained at the center of the coil. For an applied current of 2 A, then the magnetic field at the center of the coils either  standard one  or the designed one  was  7.156 x 10-5T  and 5.907  x 10-5T respectively. The value of magnetic field increases as number of turns and current are increased, for the coils with number of turns of 50 and 250 that carrying current of 1.0 A  produced a magnetic field of  5.241 x 10-5T and 6.208 x 10-5T respectively. This is due to the direct relationship between current (I) and number of turns (N) against magnetic field as expected. The value of magnetic field decreases as moving away from the center of coil either in horizontal or vertical direction.