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Eksakta : Berkala Ilmiah Bidang MIPA
Published by Universitas Negeri Padang
ISSN : -     EISSN : 25497464     DOI : https://doi.org/10.24036/eksakta/
Core Subject : Science, Education, Agriculture, Social, Engineering,
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Energy Engineering Environmental Science Materials Science & Nanotechnology Mathematics Mechanical Engineering
Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) is an open access journal and peer-reviewed that publishes either original article or reviews. The journal is dedicated towards dissemination of knowledge related to the advancement in scientific research. The prestigious interdisciplinary editorial board reflects the diversity of subjects covered in this journal. Under the realm of science and technology, the coverage includes environmental science, pure and applied mathematics, agricultural research and engineering, biology, biotechnology, bioinformatics, Healthcare sciences (including clinical medicine, preventive medicine & public health), physics, biophysics, computer science, chemistry and bioengineering, to name a few. This Journal Is Published at 3 Month intervals on January-Marc, April-June, July-September and October-December
Arjuna Subject : Umum - Umum
Articles 221 Documents
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MODEL STAR(1;1) PADA DATA PRODUKTIVITAS TEH Khafsah Joebaedi
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (871.415 KB) | DOI: 10.24036/eksakta/vol19-iss1/118

Abstract

Model STAR (1;1) atau model Space Time Auto Regresi(1;1) adalah salah satu bentuk model yang melibatkan lokasi dan waktu. Model STAR(1;1) stasioner dapat digunakan untuk prakiraan observasi di suatu lokasi pada waktu mendatang berdasarkan satu waktu sebelumnya dari lokasinya sendiri dan lokasi-lokasi lain disekitarnya. Penerapan model STAR(1;1) pada data stasioner produktivitas teh menunjukkan bahwa nilai Eigen dari matriks parameter model STAR(1;1) bernilai lebih kecil dari 1. Hal ini menunjukkan bahwa parameter model STAR(1;1) untuk data produktivitas teh tersebut memenuhi syarat stasioner.
ANALISIS RESPON PENGONTROL ON-OFF PADA KENDALI UMPAN BALIK SISTEM FISIS ELEKTRONIK Darmawan Hidayat
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (577.453 KB) | DOI: 10.24036/eksakta/vol19-iss1/119

Abstract

Pengontrol On-Off merupakan salah satu jenis aksi pengontrolan yang banyak digunakan pada kontrol otomatis di industri karena kontrol ini sederhana dan relatif murah. Terdapat dua aspek penting yang harus dipertimbangkan pada pengontrol on-off. Pertama adalah frekuensi osilasi respon yang berpengaruh pada umur ketahanan komponen aktuator. Kedua adalah amplitudo osilasi respon yang memengaruhi besar rugi-rugi energi pada respon sistem kendali keseluruhan. Makalah ini memaparkan suatu strategi dalam mengatur frekuensi dan amplitudo osilasi respon dengan menerapkan histeresis pada bagian pengontrol on-off. Pengaruh parameter waktu tunda (delay) dan penguatan (gain) histeresis terhadap frekuensi dan amplitudo osilasi respon sitem kendali on-off diteliti. Sebagai implementasi, bagian-bagian sistem pengontrol on-off meliputi detektor kesalahan dan waktu tunda histeresis diwujudkan dengan mikrokontroler AT89C51. Saklar elektronik digunakan sebagai model fisis aktuator on-off. Blok sistem proses (plant) dan umpanbalik diwujudkan dengan model fisis elektronik rangkaian resistor dan kapasitor (R dan C) orde satu. Dengan cara ini seluruh besaran fisis yang terlibat adalah berupa tegangan sehingga memudahkan dalam analisis respon sistem kendali on-off karena dapat ditampilkan pada osiloskop guna keperluan pengamatan di laboratorium. Hasil analisis respon dari eksperimen dan simulasi menunjukkan bahwa jika waktu tunda histeresis semakin besar maka frekuensi osilasi menurun namun amplitudo osilasi meningkat dan waktu settling semakin besar. Selain itu, jika penguatan histeresis semakin besar maka frekuensi osilasi respon menurun namun amplitudo osilasi meningkat dan waktu settling semakin cepat. Hasil pengujian menyimpulkan bahwa penerapan histeresis dapat menentukan performansi suatu sistem kendali on-off sehingga pengguna dapat mengatur respon sistem kendali sesuai dengan kriteria pengontrolan yang ditentukan dan diperlukan.
PENYELIDIKAN KELAYAKAN KIMIA DAN PENYEBARAN CADANGAN PASIR BESI DAERAH TIKU KABUPATEN AGAM UNTUK BAHAN BAKU SEMEN PADA PT. SEMEN PADANG Heri Prabowo
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (622.019 KB) | DOI: 10.24036/eksakta/vol19-iss1/121

Abstract

The purpose of this research is to know the mineral content of iron sand and its spreading both vertically and horizontally with the purpose of providing information and data for local government of Agam district for the development and arrangement of environment along the coast. In order to obtain information about the depth of iron sand can be used geoelectric method because one of the physical properties of metal elements including iron is to have low resistivity. In this study used resistivity mapping method that aims to determine the variation of the arrangement of soil layers vertically and horizontally. The configuration used in this method is Schlumberger configuration. To know the chemical content of iron sand is done by taking samples of iron sand systematically and represented at some point. The sample was analyzed chemical composition by XRF method (X-Ray Fluorescence), then correlated with some surface data, so that the depiction of the quality of iron sand of Tiku Regency. From the interpretation of soil resistivity value on 2 paths it can be concluded that iron sand in Tiku Beach area is in depth 0 - 20 m. Chemical content of iron sand from XRF method analysis shows Fe2O3 percentage of 10 - 35%, with TiO2 content of 1 - 3%. The quality of iron sand can be used as raw material for cement maker.
DIVERSITAS BAKTERI ENDOFIT PADA DAUN MUDA DAN TUA TUMBUHAN ANDALEH (Morus macroura miq.) Dwi Hilda Putri; Mades Fifendy; Moca Faulina putri
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (832.934 KB) | DOI: 10.24036/eksakta/vol19-iss1/122

Abstract

Endphytic microbes are microscopic living organisms (bacteria and fungi) that live in plant tissues (xylem and phloem), leaves, roots, fruit, and stems. These microbes live symbiosis of mutual benefit. Morus macroura miq. or Andaleh is a native plant of western Sumatra that is considered rare. The purpose of this study was to isolate and identify entophytic bacteria found in young leaves and old leaves andaleh taken from the village Andaleh, Kec. Batipuah West Sumatra. The methods used to isolate endophytic bacteria from andaleh leaves are spread plate and streak plate. Identification of endophytic bacteria in macroscopic or colony morphology. A total of 12 isolates of endophytic bacteria from young andaleh leaf and 8 isolates of endophytic bacteria from andaleh leaf. Identification Microscopic using gram staining obtained bacteria 18 gram positive endophytic bacterial isolates and 2 isolate gram negative bacteria.
Pengaruh Ekstrak Kulit Buah Manggis (Garcinia mangostana L.) terhadap Histologis Pankreas Mencit (Mus musculus L. Swiss Webster) yang Diinduksi Sukrosa Ramadhan Sumarmin
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (898.059 KB) | DOI: 10.24036/eksakta/vol19-iss1/123

Abstract

Diabetes Mellitus (DM) is a metabolic disorder caused by lack of insulin which islet cells of Langerhans in the pancreas were damaged or decreased. DM treatment is quite expensive so it takes the alternative medicine. Ones of alternative medicine using Mangosteen Fruit pod. The pod of the mangosteen fruit have xanton flavonoid compounds, which function as antioxidants that can lower blood glucose levels and improve pancreatic cells. The study aimed to determine the effect of mangosteen rind extract (Garcinia mangostana L.) to display the pancreatic histology of mice (Mus musculus L. Swiss Webster) induced male sucrose. This study used Completely Randomized Design (CRD) with 5 treatments and 5 replications. treatments is P1 (positive control), sucrose 0.8 g/kg (negative control / P2), sucrose + 200 mg/kg of mangosteen peel extract (P3), sucrose + 400 g/kg of mangosteen peel extract ( P4), sucrose + 600 mg/kg of mangosteen peel extract (P5). Observations quantitatively to determine blood glucose levels and the number of Langerhans islet cells after 5 days and 4 days inducing the extract. Data were analyzed by ANOVA, if there is a difference will be continued with Duncan test at the 0.05 significance level. The results showed the average number of Langerhans islet cells 205.6 (P1), 134.0 cells (P2), 114.2 cells (P3), 193.0 cell (P4), and 181.8 cells (P5). From the results obtained in the analysis of data obtained Fhitung<Ftabel significant at 0.05, so it can be concluded that the mangosteen rind extract has no effect on pancreatic histological induced male mice sucrose.
PENGARUH EKSTRAK DAUN SIRIH MERAH (Piper crocatum Ruiz & Pav.) TERHADAP GLUKOSA DARAH MENCIT (Mus musculus L.) JANTAN YANG DIINDUKSI SUKROSA Muhammad Rizki Saputra; Ramadhan Sumarmin
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (584.961 KB) | DOI: 10.24036/eksakta/vol19-iss1/124

Abstract

Patients withdiabetes mellitus(DM) continues to grow becauseprosperityandpeople's lifestyles.Treatment of diabetesoften useinjectionsof insulinandoralantidiabeticdrugs. Thetreatmenthas no side effects. Therefore, it isnecessary to findeffective drugsusing plantsthatred betelleaf(Piper crocatumRuiz&Pav.). Red betel leafcontains flavonoidswhichare antioxidants. This study aimsto determine the effectand dose ofextractof redbetel leaf(Piper crocatumRuiz&Pav.) The mosteffectiveagainstbloodglucosein mice(Mus musculusL.) maleinducedsucrose.This study was an experimental study. The research was conducted in October 2015 in the Division of Laboratory Animal and Zoology Department of Biology, State University of Padang. The subject of research in the form of mice (Mus musculus L.) males totaled 24 tails. The design used was completely randomized design (CRD) with 6 treatments and 4 repetitions. The treatment is given as follows: treatment I: the diabetes control without any treatment given, treatment II: as a negative control (sucrose 3 g/kg bw), treatment III: sucrose+suspension of red betel leaf extract (dosage 0,7 g/kg bw), treatment IV: sucrose+suspension of red betel leaf extract (dosage 1,4 g/kg bw), treatment V: sucrose+suspension of red betel leaf extract (dosage of 2,1 g/kg bw) and treatment VI: sucrose+suspension extracts red betel leaf (dosage 2,8 g/kg bw).The results showed that the extract of red betel leaf (Piper crocatum Ruiz & Pav.) at a dose of 0,8 g/kg bw 1,4 g/kg bw 2,1 g/kg bw and 2,8 g/kg bw can lowers blood glucose in mice. However, the most appropriate dose in lowering blood glucose in mice (Mus musculus L.) at 2,8 g/kg bw in mice.
SUB RUANG TUTUP TOPOLOGI HASIL KALI RUANG METRIK KERUCUT Badrulfalah Badrulfalah
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (733.019 KB) | DOI: 10.24036/eksakta/vol19-iss1/128

Abstract

Sebuah sifat topologi selain dapat dimiliki oleh suatu ruang topologi juga dapat dimiliki oleh subruang dari ruang topologi tersebut. Pada makalah ini akan dibahas tentang aksioma keterhitungan pertama pada topologi hasil kali ruang metrik kerucut, khususnya pada subruang tutup. Pembahasan dilakukan dengan menunjukkan bahwa setiap elemen dari setiap subruang tutup dari topologi hasil kali dua ruang metrik kerucut memiliki basis lokal terhitung. Hasilnya adalah setiap subruang tutup dari topologi hasil kali ruang metrik kerucut juga memenuhi aksioma keterhitungan pertama. Dengan kata lain keterhitungan pertama bersifat hereditas lemah.
BEBERAPA SYARAT CUKUP UNTUK BILANGAN KROMATIK LOKASI HINGGA PADA GRAF TAK TERHUBUNG Des Welyyanti
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1114.488 KB) | DOI: 10.24036/eksakta/vol19-iss1/130

Abstract

The locating-chromatic number of a graph is introduced by Chartrand et al. in 2002. Firstly, Chatrand et al. determine the locating-chromatic number of path and double stars. The locating-chromatic number is an interesting concept ini graph theory. In this paper, we determine some condtions for disconnected graphs has a finite locating-chromatic number.
DEGRADASI METIL VIOLET MENGGUNAKAN KATALIS ZnO-TiO2 SECARA FOTOSONOLISIS Hary Sanjaya
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1047.3 KB) | DOI: 10.24036/eksakta/vol19-iss1/131

Abstract

Research on the degradation of methyl violet has been done by using photosonolysis method. The purpose of this study is to determine how much time the optimum, optimum pH and the amount of doping TiO2 optimum degrade methyl violet as well as the percent degradation, determined the crystal structure and particle size of the catalyst synthesis of ZnO-TiO2 optimum degrade methyl violet using XRD, determine the value of the band gap Of the optimum ZnO-TiO2 catalyst synthesis in degrading methyl violet using UV-DRS, determining the absorption peak of Zn-O-Ti bonds from optimum ZnO-TiO2 catalyst synthesis in degrading methyl violet using FTIR. The results showed that the optimum time to degrade methyl violet was 45 minutes with 94,1371% degradation percentage. For pH variation, the optimum degradation results at pH 6 with percent degradation of 99.2857%. The effect of TiO2 doping variation showed optimum degradation result obtained on doping variation of TiO2 5% with percentage degradation of 96,2500%. The optimum catalyst structure of ZnO-TiO2 catalyst in degrading methyl violet with XRD is wurtzite (anatase) and the particle size is 42.65 - 107.60 nm. The band gap value of the optimum ZnO-TiO2 catalyst in degrading methyl violet with UV-DRS is 3.18 eV. The absorption peak of ZnO-Ti for optimum catalyst ZnO-TiO2 in degrading methyl violet with FTIR is 745.70 cm-1.
DIAGONALISASI BENTUK KUADRATIK IRISAN KERUCUT Yusmet Rizal
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 19 No. 1 (2018): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (722.322 KB) | DOI: 10.24036/eksakta/vol19-iss1/132

Abstract

In general, the conic section equation consists of three parts, namely quadratic, cross-product, and linear terms. A conic sections will be easily determined by its shape if it does not contain cross-product term, otherwise it is difficult to determine. Analytically a cone slice is a quadratic form of equation. A concept in linear algebraic discussion can be applied to facilitate the discovery of a shape of a conic section. The process of diagonalization can transform a quadratic form into another form which does not contain crosslinking tribes, ie by diagonalizing the quadrate portion. Hence this paper presents the application of an algebraic concept to find a form of conic sections.

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