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Elektron ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 105-111
Author(s):  
Leonardo Martín Carducci ◽  
Ramiro Alfonso ◽  
Walter Gustavo Fano

En este artículo se presenta el análisis de la etapa analógica de un receptor de campo magnético para frecuencias extremadamente bajas (ELF). Se describen detalles sobre la caracterización y modelado de la antena utilizada, así como el comportamiento en frecuencia del sistema. Para lograr una mayor sensibilidad, se fabricó una bobina con una inductancia considerablemente alta (800 H), además de una etapa de amplificación de alta ganancia (88 dB). Se definió un modelo de circuito equivalente para la antena y se determinaron sus elementos parásitos mediante mediciones de laboratorio y aproximaciones computacionales. El sistema de adquisición tiene una etapa de digitalización con una frecuencia de muestreo de 100 Hz. Para estudiar su comportamiento frente a posibles efectos de aliasing, se realizó un análisis de la etapa analógica en el dominio de la frecuencia determinando las condiciones óptimas de funcionamiento. Las pruebas de campo del equipo se llevaron a cabo en las sierras de Villa Alpina, Córdoba, Argentina. Teniendo en cuenta que el sistema fue diseñado para la medición y estudio de fenómenos electromagnéticos naturales en la banda ELF, se han logrado detectar con éxito las primeras seis resonancias de Schumann.


Author(s):  
Yuyun Setyawati ◽  
Sudarti Sudarti ◽  
Albertus Djoko Lesmono

ABSTRAKRoti tawar adalah sumber karbohidrat memiliki umur simpan yang sangat pendek yakni empat sampai enam hari terhitung dari proses masa produksi. Penelitian ini bertujuan menyelidiki pengaruh paparan medan magnet Extremely Low Frequency (ELF) intensitas 500 µT dan 700 µT selama 60, 90, dan 120 menit terhadap pH roti tawar. Jenis penelitian yang digunakan yaitu eksperimen dengan desain penelitian Rancang Acak Lengkap (RAL). Ada dua kelompok dalam penelitian ini, yakni kelompok kontrol dan kelompok eksperimen dimana kelompok kontrol yang tidak dipapari medan magnet dan kelompok eksperimen diberi paparan medan magnet. Sampel yang digunakan dalam penelitian ini adalah roti tawar sari roti kupas sebanyak 126 sisir dimana kelompok kontrol sebanyak 18 sisir roti tawar dan kelompok eskperimen sebanyak 108 sisir roti tawar yang dibagi menjadi enam kelompok yang diberi perlakukan berupa paparan medan magnet ELF dengan intensitas 500 µT dan 700 µT selama 60, 90 dan 120 menit. Teknik analisis data dilakukan menggunakan SPSS 22 dengan uji Kruskal-Wallis.  Berdasarkan hasil penelitian yang diperoleh paparan medan magnet ELF berpengaruh terhadap perubahan pH pada roti tawar. Dengan memaparkan medan magnet intensitas 500 µT lama paparan 60 menit dan 700 µT lama paparan 60 menit dapat menghambat penurunan pH roti tawar. Kata kunci: Medan Magnet ELF; Roti Tawar; pH. ABSTRACTBread is a source of carbohydrates that has a very short shelf life of four to six days from the production process. This study aims to examine the effect of exposure to an Extremely Low Frequency (ELF) magnetic field with an intensity of 500 µT and 700 µT for 60, 90, and 120 minutes on the pH of white bread. This research uses an experimental research type with the research design used is Completely Randomized Design (CRD). There were two groups in this study, namely the control group and the experimental group where the control group was not exposed to a magnetic field and the experimental group was exposed to a magnetic field. The samples used in this study were 126 combs of peeled white bread, where the control group consisted of 18 white bread combs and the experimental group consisted of 108 white bread combs which were divided into six groups which were treated in the form of exposure to the ELF magnetic field with an intensity of 500 µT and 700 µT for 60, 90 and 120 minutes. The data analysis technique was carried out using SPSS 22 with the Kruskal-Wallis test. The results of the study stated that exposure to the ELF magnetic field had an effect on changes in pH in white bread as shown by a graphic diagram. Exposure to a magnetic field intensity of 500 µT with an exposure time of 60 minutes and 700 µT with an exposure duration of 60 minutes can inhibit the decrease in the pH of white bread. Keywords: Magnetic Field; White Bread; pH.


2021 ◽  
Vol 4 (2) ◽  
pp. 129-136
Author(s):  
Mamik Purbawati ◽  
Sudarti Sudarti ◽  
Firdha Kusuma A A

ABSTRAK Kopi lanang (Peaberry) merupakan jenis kopi yang mempunyai biji berkeping satu (monokotil) dengan kafein yang kadarnya lebih tinggi jika dibandingkan dengan kopi jenis lain. Kadar kafein yang tinggi pada biji kopi bisa diturunkan dengan proses fermentasi kopi. Penelitian ini mempunyai tujuan untuk mengetahui pengaruh paparan medan magnet ELF (Extremely Low Frequency) terhadap perubahan pH pada proses fermentasi biji kopi lanang (Peaberry) kering jenis robusta dengan penambahan enzim -amilase. Jenis penelitian yang digunakan yaitu penelitian eksperimen dengan desain Rancangan Acak Lengkap (RAL) bertujuan mengkaji pengaruh perlakuan dengan pengulangan percobaan. Penelitian ini memiliki tujuh kelompok sampel meliputi kelompok kontrol dan kelompok eksperimen variasi intensitas paparan medan manet ELF sebesar 200 µT dan 300 µT dan variasi lama pemaparan 30 menit, 60 menit dan 90 menit. Pengukuran data hasil penelitian diambil setelah pemaparan yaitu pada hari ke-1 sampai hari ke-5 selama proses fermentasi berlangsung. Hasil penelitian menyatakan bahwa paparan medan magnet ELF berpengaruh terhadap perubahan pH pada proses fermentasi biji kopi lanang (Peaberry) kering jenis robusta yang ditunjukkan dengan variasi bentuk grafik. Pemaparan medan magnet ELF dengan intensitas 200 µT dan lama pemaparan 30 menit dapat menurunkan pH secara signifikan, sedangkan intensitas 200 µT dan lama waktu paparan 90 menit dapat menaikkan pH secara signifikan pada proses fermentasi biji kopi lanang (Peaberry) kering jenis robusta. Kata  kunci : Medan magnet ELF, Fermentasi, Kopi Lanang (Peaberry), pH ABSTRACT Peaberry coffee is a type of coffee that has a single bean (monocotyle) with a higher levels of caffeine if compared whith other types of coffee. High levels of caffeine in coffee beans can be reduced by the coffee fermentation process. The study aims to examine the effect of exposure to the ELF (Extremely Low Frequency) magnetic field on changes of pH in the fermentation process of robusta peaberry dray coffee beans with the addition of -amylase enzyme. The type of research that use in the experimental reseacrh with a randomized subject post test only control grup design, it aiming to examine the effect of treatment by repeating the experiment. This study include seven sample groups covering the control group and the experimental group variation in the intensity of ELF magnetic field with 200 µT and 300 µT and variation of a length 30, 60, 90 minutes. Meansurement of the data research taken after exposure that is on the day one to day five during the fermentation process. The result of the study suggest that exposure to ELF magnetic field has an effect on the pH fermentation prosess of dried peaberry coffee beans, which was shown variations of the shape of the graph. Exposure to the ELF magnetic field with an intensity of 200 µT and the length of 30 minutes can significantly decrease the pH, while the intensity of 200 µT and the length of 30 minutes can significantly increase the pH in the fermentation process of dried robusta paberry coffee beans. Keywords : ELF magnetic field, Fermentation, Peaberry Coffee, pH


2021 ◽  
Vol 2 (2) ◽  
pp. 62
Author(s):  
Rosdiana Afifah Rahman ◽  
Sudarti Sudarti

One of the plants that can thrive in Indonesia is guava. Indonesian people are familiar with water guava, and the fruit is often consumed by the public. However, water guava will rot quickly if not stored properly. Therefore, we need a method to preserve water guava without reducing the content contained in it. This article aims to analyze the effect of exposure to the ELF magnetic field on pH, density, and physical quality of water guava. The method used in this research is a laboratory experiment with a completely randomized design. This study used a magnetic field exposure of 500 T. The duration of exposure is divided into three, namely 60 minutes, 90 minutes, and 120 minutes. This study was conducted for 4 days with the variables measured in this study namely pH, density, and physical quality of water guava. Measurement of each variable was carried out every day for 4 days.


Author(s):  
Enik Wasiah Niati ◽  
Sudarti Sudarti ◽  
Yushardi Yushardi

ABSTRAKMedan magnet ELF merupakan gelombang elektromagnetik dengan frekuensi sampai 300 Hz dan tergolong sebagai radiasi non ionizing. Penelitian ini menggunakan desain randomized subject post-test only control group design, dengan pembagian dua kelompok subjek penelitian dipilih secara acak. Penelitian ini bertujuan untuk mengetahui pengaruh paparan medan magnet ELF .terhadap nilai pH buah anggur hitam. Dalam penelitian ini ada dua kelompok yaitu kelompok kontrol dan eksperimen, dimana kelompok eksperimen diberi perlakuan medan magnet  ELF intensitas 300μT dan 500μT selama 60’ dan 120’ untuk masing-masing intensitas. Analisa data nilai pH buah anggur menggunakan SPSS 24 yaitu uji kruskal wallis. Berdasarkan hasil analisa data didapat bahwa medan magnet ELF intensitas 300μT dan 500μT  berpengaruh terhadap nilai pH buah anggur hitam. Nilai pH kelompok kontrol lebih tinggi dari kelompok eksperimen. Hal ini disebabkan karena intensitas di bawah 500μT menekan pertumbuhan mikroorganisme pembentuk asam didalam buah angggur hitam. Kata kunci: medan magnet ELF; analisa data; pH. ABSTRACTThe ELF magnetic field is an electromagnetic wave with a frequency of up to 300 Hz and is classified as non-ionizing radiation. This study used a randomized subject post-test only control group design, with the division of two groups of research subjects randomly selected. This study aims to determine the effect of exposure to ELF magnetic fields on the pH value of black grapes. In this study, there were two groups, namely the control and experimental groups, where the experimental group was treated with an ELF magnetic field with an intensity of 300μT and 500μT for 60 'and 120' for each intensity. The data analysis of the pH value of grapes used SPSS 24, namely the kruskal wallis test. Based on the results of data analysis, it was found that the ELF magnetic field with the intensity of 300μT and 500μT had an effect on the pH value of black grapes. The pH value of the control group was higher than the experimental group. This is because the intensity below 500μT suppresses the growth of acid-forming microorganisms in the black grapefruit. Keywords: ELF magnetic field; data analysis; pH.


2021 ◽  
Vol 169 ◽  
pp. 836-842 ◽  
Author(s):  
Cristilane M. de Andrade ◽  
Antonio J.D. Cogo ◽  
Victor Haber Perez ◽  
Nathalia F. dos Santos ◽  
Anna Lvovna Okorokova-Façanha ◽  
...  

2021 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
Karina Laksmiari ◽  
Sudarti Sudarti

The Extremely Low Frequency (ELF) magnetic field is a component of the electromagnetic wave spectrum with a frequency of <300 Hz. This research is an experimental study with the aim of examining the effect of exposure to Extremely Low Frequency (ELF) magnetic fields on the mass of chili plants (Capsicum annum L). Data collection techniques used are direct measurements. The results showed that chilli seeds exposed to a 300µT ELF magnetic field for 30 minutes gave a fresher and drier mass than the other samples. The use of a 30-minute duration ELF 300µT magnetic field on chili seeds gave better results for fresh and dry mass of chili plants.


Author(s):  
Nanda Rizky Fitrian Kanza ◽  
Sudarti Sudarti ◽  
Maryani Maryani

ABSTRAKPenelitian ini bertujuan untuk mengkaji pengaruh paparan medan magnet Extremely Low Frequency (ELF) terhadap pH dan daya hantar listrik pada proses fermentasi basah kopi liberika dengan penambahan α-amilase. Jenis penelitian ini merupakan penelitian eksperimen dengan randomized subjects post test only control group design. Pada penelitian ini terdapat 7 perlakuan yang terdiri dari kelompok kontrol dan kelompok eksprimen yang dipapar medan magnet ELF dengan variasi intensitas 300 µT dan 400 µT dan variasi lama paparan 30 menit, 60 menit, dan 90 menit. Pengambilan data dilakukan pada jam ke-24, jam ke-48, hari ke-3, hari ke-4, dan hari ke-5 setelah proses fermentasi. Hasil penelitian menunjukkan bahwa paparan medan magnet Extremely Low Frequency (ELF) berpengaruh terhadap pH dan daya hantar listrik pada proses fermentasi basah kopi liberika dengan penambahan α-amilase yang ditunjukkan dengan bervariasinya grafik. Pengukuran kopi liberika dengan paparan medan magnet ELF intensitas 400 µT selama 30 menit paling berpengaruh terhadap pH kopi liberika. Sedangkan, pengukuran kopi liberika dengan paparan medan magnet ELF intensitas 300 µT selama 30 menit dan 90 menit paling berpengaruh terhadap daya hantar listrik kopi liberika yang telah difermentasi secara basah dengan penambahan α-amilase. Kata kunci: medan magnet ELF; pH; daya hantar listrik; fermentasi; kopi. ABSTRACTThe purpose of the research is to examine the effect of Extremely Low Frequency (ELF) magnetic field to pH and electrical conductivity in the wet fermentation process of liberica coffee with the addition of α-amylase. Type of the research is an experimental research with randomized subjects post test only control group design. There is seven treatments consist of control group and experimental group exposed to ELF magnetic field with 300 µT and 400 µT intensity variation and for 30, 60, and 90 minutes for long variations. For hours 24, 48, day 3, day 4, and day 5, can make data retrieval after fermentation process. The result explain is effect of Extremely Low Frequency (ELF) magnetic field to pH and electrical conductivity in the wet fermentation process of liberica coffee with the addition of α-amylase was take effect to indicated by the variation of the graph. The process ELF magnetic field with 400 µT intensity for 30 minutes most influential on pH of liberica coffee. Meanwhile, the process ELF magnetic field with 300 µT intensity for 30 and 90 minutes most influential on electrical conductivity of liberica coffee in the wet fermentation with the addition of α-amylase. Keywords: ELF magnetic field; pH; electrical conductivity; fermentation; coffee.


2020 ◽  
Vol 41 (5) ◽  
pp. 382-391
Author(s):  
Leandro Vives ◽  
Juan Balsalobre ◽  
Tiago Monteiro ◽  
Javier G. Diaz ◽  
Gustavo Liponetzky ◽  
...  

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