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Jurnal Teori dan Aplikasi Fisika
Published by Universitas Lampung
ISSN : 2303016X     EISSN : 25491156     DOI : -
Core Subject : Science,
Jurnal ini diterbitkan oleh Jurusan Fisika Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Lampung sebagai sarana untuk mempublikasikan hasil penelitian, artikel review dari peneliti-peneliti di bidang fisika teori dan aplikasinya. Jurnal ini terbit dua kali setahun (Januari dan Juli).
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Articles 15 Documents
Search results for , issue "Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika" : 15 Documents clear
Studi Pendahuluan Pembentukan Struktur Komposit Perak Silika (Ag/SiO2) Berbasis Sekam Padi Janariah Janariah; Jessy Oktayulia Sari; Simon Sembiring; Junaidi Junaidi
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2889

Abstract

Penelitian mengenai sintesis komposit perak silika (Ag/SiO2) telah dilakukan melalui metode sol-gel dengan menggunakan variasi konsentrasi koloid perak nitrat (AgNO3) yaitu 0,3; 0,5; dan 0,7 M ke dalam sol silika sekam padi dengan perlakuan termal suhu 110 oC dan suhu  sintering 850 oC. Tujuan dari penelitian ini yaitu sebagai studi pendahuluan pembentukan struktur komposit Ag/SiO2 melalui karakterisasi X-ray diffraction (XRD). Analisis XRD menunjukkan bahwa jumlah konsentrasi AgNO3 mempengaruhi kenaikan intensitas pada 2θ. Pada konsentrasi 0,3 M struktur silika (SiO2) yang dihasilkan masih dalam bentuk amorf dan intensitas perak (Ag) tidak terlalu besar, sehingga dengan penambahan konsentrasi 0,5 dan 0,7 M intensitas struktur puncak silika sudah terlihat dan bertambahnya intensitas puncak dari struktur perak.
The Effect Of Exposure Index Variations On Subjective Quality Assessment On Lumbosacral Examination Putri Rahmawanti; Muhammad Irsal; Gando Sari
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2922

Abstract

Exposure index (EI) is an indicator of dose used to determine overexposed, optimal and underexposed images so that this study discusses the effect of EI variations on subjective image quality assessment on lumbosacral examination. This research uses descriptive quantitative method by filling out questionnaires and calculating the radiation output dose. Then to draw conclusions, perform a visual grading analysis (VGA) statistical test using the one-way ANOVA test. The results obtained by varying the EI for AP projections of 2.99 (overexposed), 2.79 (optimal), and 2.33 (underexposed) then for Lateral projections of 2.91 (overexposed), 2.76 (optimal), and 2.46 (underexposed). Furthermore, the dose calculation using the radiation output equation produces 3.158 mGy (overexposed), 0.78 mGy (optimal) and 0.57 mGy (underexposed) for the AP projection while for the lateral projection it produces a radiation dose of 3.61 mGy (overexposed), 1.52 mGy (optimal). , and 0.78 mGy (underexposed). Then to get a conclusion, VGA test was carried out using ANOVA testing, the data generated after performing ANOVA tests on AP and lateral projections showed results of 0.87 and 0.612. Based on the results of the ANOVA that has been carried out, the conclusion is that all respondents have the same assessment of the quality of the lumbosacral image that the image with the overexposed EI indicator is a better image than the image with the optimal and underexposed EI indicator.
Fabrikasi Nanofiber PVA/Fe3O4 dengan Metode Elektrospinning Nuril Fathurin; Diah Hari Kusumawati
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2911

Abstract

PVA/Fe3O nanofibers are composite materials contain magnetic materials in nanometer-sized fibers that have biocompatible, non-toxic, and high chemical stability properties. It makes Fe3O nanoparticles suitable for application in the biomedical field as a Drug Delivery System or targeted drug delivery system. Fe3O will be composited with Polyvinyl Alcohol (PVA) and formed into nanofibers. The purpose of this study was to analize the effect of variations in volume % concentration of F Fe3O used on PVA/Fe3O nanofibers. Fe3O was dissolved in dionized water using ultrasonication. The suspension of  Fe3O solution was mixed with 10% PVA solution to form PVA/Fe3O solution with Fe3O variations of 5%, 10%, 15%, and 20%. Electrospinning process was carried out on PVA/Fe3O solution with a voltage of 20 kV, flow rate of 5 ml/hour, distance of jet to collector is 15 cm. The results of SEM characterization can be concluded that the one that has the best morphology in this study is PVA/Fe3O nanofiber with a concentration of 10% because it generates uniform nanofibers with the smallest diameter at this concentration, the fibers do not attach to one other, and there are no beads.
Studi Pendahuluan Pembentukan Gugus Fungsi dari Komposit Perak Silika (Ag/SiO2) Berbasis Sekam Padi Rifa Dian Eka Farah; Nur Fattiah Amanda; Simon Sembiring; Junaidi Junaidi
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2891

Abstract

Research has been carried out with the aim of studying the formation of functional groups of a composite of silver silica (Ag/SiO2) based on rice husk silica and silver nitrate (AgNO3) as a precursor using the sol-gel method. Variations in the concentration of AgNO3 used were 0,3M; 0,5M; and 0,7 M with a thermal temperature of 850 °C. The results of Fourier transform infrared spectroscopy (FTIR) showed the formation of Si-O-Si, Si-O, and O-N-O functional groups which were the result of AgNO3 residue indicating the presence of Ag.
INVESTIGATION OF NATURAL EXTRACTS AS GREEN CORROSION INHIBITORS IN STEEL USING DENSITY FUNCTIONAL THEORY Muhamad Akrom
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2927

Abstract

One of the materials with low corrosion resistance is steel when it interacts with a corrosive environment. The use of green inhibitors is able to provide good corrosion inhibition performance with high inhibition efficiency on steel. Green inhibitors which in their compound structure contain heteroatom groups (such as O, N, S, P) and aromatic rings are efficiently used as corrosion inhibitors in steel. This paper provides an important comparative overview for the development of green inhibitors of natural extracts in steel. The study of DFT at the atomic level based on molecular orbitals, chemical quantum parameters, and adsorption characteristics showed results that were in accordance with experimental results. The distribution of electron density through the Frontier Molecular Orbitals (FMO) plot illustrates the prediction of active sites through the distribution of the HOMO-LUMO region of inhibitor molecules that interact with the steel surface. To get the correlation between the electronic properties of the inhibitor molecule and the corrosion inhibition potential, calculate the quantum chemical parameters such as ionization potential (I), electron affinity (A), global hardness (η), absolute electronegativity (χ), global softness (σ) , the transferred electron fraction (ΔN), global electrophilicity (ɷ) and electron return donation (ΔEback-donation) indicate the reactivity of inhibitor molecules which have excellent potential to interact and bind strongly to metal surfaces, thus potentially producing high inhibitory efficiency. The mechanism of corrosion inhibition can be through chemical adsorption and/or physical adsorption by forming a complex compound between the inhibitor molecule and the steel surface to protect it from the corrosive environment. The development of future studies should be able to display the mechanism of interaction and inhibition of inhibitor molecules in more detail and systematically at the atomic level on several metal surfaces such as Fe, Al, Cu, and others.
Analisis Uji Peluncuran Roket Air Berbasis Carbon Fiber Menggunakan Sistem Telemetri Qonitatul Hidayah; Umi Salamah; Margi Sasono
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2912

Abstract

Rocket technology with water propellant is becoming more popular and as an alternative to be applied to education and recreation, such as industry and the military. The use of water rockets as an easy, safe, and inexpensive means of measuring physical parameters at heights above the earth's surface is being intensively carried out. One alternative solution is aerodynamic water rocket technology equipped with a telemetry system. The rocket used for the test launch is made from untested carbon fiber. Flight test settings by filling 1/3 of the tube volume with water and a pressure of 200 psi. The results of the water rocket launch show a maximum height of 265 feet or 80.77 m. Changes in acceleration on the x-axis, y-axis, and z-axis indicate the normal motion of the flying rocket. Analysis of stability and control of the rocket is seen in the measurement of the tilt angle of roll, pitch, and yaw. When the rocket moves or tilts, the angle measured corresponds to the tilt. In the roll condition, the rocket moving from launch to landing shows the rocket's rotational motion at an angle of approximately 20o. The potential of water rockets that can still be developed, needs to be increased the reliability of water rockets both in terms of utilization and research.
KARAKTERISTIK STRUKTUR DAN TERMAL KOMPOSIT ASPAL KARBOSIL SILIKA SEKAM PADI Devi Yulianti; Simon Sembiring; Junaidi Junaidi
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2898

Abstract

Telah dilakukan sintesis dan karakterisasi aspal yang dimodifikasi dengan karbosil dan silika. Penelitian ini dilakukan untuk mengetahui mikrosuktur dan struktur komposit aspal karbosil silika dengan perbandingan komposisi berat yaitu 50:50:0; 42,5:42,5:15; 40:40:20; 37,5:37,5:25; 35:35:30; 32,5:32,5:35. Silika diperoleh dengan menggunakan metode alkalis dan karbosil diperoleh dengan metode pirolisis. Hasil analisis XRD diperoleh fasa yang terbentuk dari setiap variasi komposisi adalah fasa amorf. Analisis DTA/TGA menunjukkan terjadinya perubahan energi akibat penambahan panas dengan ditandai adanya penyusutan massa pada sampel. Variasi komposisi pada sampel menunjukkan terjadinya penurunan nilai pada kuat tekan, porositas dan perubahan ketebalan.
Local Adaptive Thresholding Menggunakan Metode Sauvola sebagai Tahapan Pra Pengolahan pada Data Citra Isyarat ECG Mohammad Rofi'i; Diah Rahayu Ningtias
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2904

Abstract

Kondisi seseorang dapat diketahui dari aktivitas kelistrikan jantung yang telah direkam dan dicetak dalam bentuk electrocardiogram (ECG). Data ECG dapat digunakan dalam penelitian sebagai modalitas bahan untuk analisis dan diagnosis kondisi jantung. Data tersebut dapat berupa isyarat satu dimensi maupun isyarat dua dimensi dalam bentuk citra atau gambar. Pengolahan isyarat ECG yang diambil dari data cetak fisik di scan untuk mendapatkan data digital sehingga dapat diolah dengan menggunakan komputer. Penelitian ini bertujuan untuk mempersiapkan data citra ECG dalam tahap pra pengolahan yang siap diolah pada tahap selanjutnya, baik untuk keperluan analisis maupun diagnosis melalui data citra ECG. Sehingga diharapkan dapat memudahkan dan menampilkan hasil yang optimal untuk berbagai penelitian dengan modalitas data citra ECG.Algoritma yang diterapkan menggunakan metode pengambangan lokal dari sauvola tecnique. Dengan menggunakan nilai R sebesar 128 dan nilai k=0,34 telah menghasilkan citra isyarat ECG tersegmentasi yang bersih tanpa grid. Dengan melihat nilai MSE dan PSNR dari masing-masing metode menunjukkan algoritma sauvola mendapatkan hasil yang lebih baik dari pengambagan global.
THE INFLUENCE OF ELECTRICAL VOLTAGE ON FORMATION OF SILICA NANO FIBER WITH ELECTROSPINNING METHOD Erika Sempana Ginting; Posman Manurung; Yanti Yulianti
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2907

Abstract

Silica nanofibers have been successfully fabricated using electrospinning method. Silica solution was prepared with molar rasio of tetraethyl orthosilicate (TEOS): ethanol: aquabides:hydrogen chloride (HCl) of 1 : 10 : 3 : 0.04. Polyvinyl alcohol (PVA) of 10% was added to solution. The solutions were then mixed with a ratio of silica: PVA solution of 2: 3 ml. The functional group of silica/PVA was characterized by Fourier transform Infrared Spectroscopy (FTIR). Morphology and elements analysis was tested by Scanning Electron Microscopy - Energy Dispersive Spectroscopy (SEM - EDS). The functional groups of silica/PVA solution formed are –OH, C-H, CH2, C=O, Si-O, and Si-O-Si which indicate the occurrence of cross-linking between silica and PVA. The functional groups shown in the solution are still visible on the silica nanofibers in the presence of C, O, and Si elements in the EDS results of the nanosilica fibers. The surface morphology shows that the silica nanofibers are more continuous and the beads are relatively less with increasing electrospinning voltage. The average fiber diameter by taking into account the estimated standard deviation, shows a graph with a linear trend and increasing the applied electrospinning voltage. Silica nanofibers with diameter range (80-150) nm are obtained
Aplikasi Styrofoam Sebagai Absorpsi Bunyi Allif Silfiyana Rohman; Agus Yulianto; Upik Nurbaiti
Jurnal Teori dan Aplikasi Fisika Vol 10, No 1 (2022): Jurnal Teori dan Aplikasi Fisika
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtaf.v10i1.2817

Abstract

This study aims to determine the level of sound attenuation of Styrofoam material. This research is using a noise meter application Decibel X: dB Sound Level Meter and a sound generator as a sound source. Then Styrofoam as an acoustic material with a thickness of 1 cm; 1.5 cm; 2 cm; 2.5 cm ; 3 cm; 3.5 cm and 4 cm. The average absorption coefficient obtained in this study with a material thickness of 1 cm is 0.023. Then the average absorption coefficient at a thickness of 1.5 cm is 0.031. While the average absorption coefficient at a material thickness of 2 cm is 0.040. Furthermore, the average sound absorption coefficient at a thickness of 2.5 cm and 3 cm has the same value, namely 0.039. Then, the average sound absorption coefficient at a thickness of 3.5 cm and 4 cm also has the same value, which is 0.038. Based on the research that has been done, it can be concluded that sound absorption at frequencies below 1000 Hz occurs significant sound absorption. At frequencies of 200 Hz, 400 Hz, 600 Hz and 800 Hz, the average sound absorption increases from 1 cm to 3.5 cm of Styrofoam thickness. While the thickness of Styrofoam 4 cm on average did not show a significant increase in sound absorption. Styrofoam thickness of 4 cm can effectively absorb sound at a frequency of 1000 Hz only.

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