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JFA (Jurnal Fisika dan Aplikasinya)
ISSN : 1858036X     EISSN : 24604682     DOI : -
Core Subject : Science,
JFA (Jurnal Fisika dan Aplikasinya, Abbreviation: J.Fis. dan Apl.) hanya menerbitkan artikel penelitian asli serta mengulas artikel tentang topik seputar bidang fisika (fisika teori, material, optik, instrumentasi, geofisika) dan aplikasinya. Naskah yang dikirimkan ke JFA belum pernah diterbitkan ditempat lain serta tidak dalam proses pertimbangan untuk diterbitkan ditempat lain, dalam bahasa apapun. Studi teoritis, eksperimental, dan praktis sama-sama didorong, seperti juga artikel interdisipliner dan yang timbul dari penelitian dan kolaborasi industri.
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Articles 5 Documents
Search results for , issue "Vol 18, No 1 (2022)" : 5 Documents clear
Improvement of Soundscapes Based on Noise Control in Urban Forest as an Effort to Fulfill Quality of Green Open Space Standards suyatno suyatno; Lailatul Inayah; Susilo Indrawati
Jurnal Fisika dan Aplikasinya Vol 18, No 1 (2022)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v18i1.12040

Abstract

Urban forests play an important role in green open spaces. Urban forests have aesthetic functions and social functions that refer to the quality standards. Urban noise causes city forest soundscapes to be less comfortable and less aesthetic so that its function as a green open space is not fulfilled. This study aims to improve the quality of sound in urban forests (soundscape) based on the quality of green open space standards through noise control and find out the type of improvement most preferred by visitors. The quality of standard of green open space is pursued through sound masking, active noise cancellation, and convolution in sound signal conditioning. The convoluted sound signal is traffic noise with a convolved signal in the form of bird noise, water rush, and relaxation music. From the results of the improvement of the sound signal then tested on 30 respondents through a comparison test method. The subjective acoustic parameters of the environment are identified, which includes the value of the autocorrelation function (τ1, φ1) and dynamic range (DR). Efforts to improve the quality of acoustics based on the quality of green open space the most preferred by respondents were sound masking and ANC with birdsong with successive scores 4.44 and 2.78. The results of identification of traffic noise treated by ANC and sound masking with songbird obtained values DR = 32.35 dBA, τ1 = 0.73 s, and φ1 = 0.03. These parameters describe these sounds tend to be preferred because the human ear is more sensitive with high pitch and DR.
The Role of On-site Coulumb Interaction on Electronic Structure of FeO Ramli, Irwan; Arfa, Nirmala; Manrulu, Rahma Hi; Jusmi, Fitri
Jurnal Fisika dan Aplikasinya Vol 18, No 1 (2022)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v18i1.8055

Abstract

We report our density functional theory (DFT) calculation on FeO in order to describe its electronic properties. FeO exhibits an antiferromagnetic at the ground state with cubic structure and Neel temperature TN = 198 K. The DFT calculation is as powerful tool to describe electronic properties but known to be failed to describe the electronic properties of system with strong on-site Coulomb interaction such as FeO. Here, we introduce the Hubbard correction, U, in order to take into account the on-site Coulomb interaction of d-electron at Fe ion. Hybridization of 3d-electron of Fe and 2p-electron of O splits the energy level to become upper Hubbard band (UHB) and low Hubbard band (LHB). Based on the DFT+U calculation, the band structure of FeO shows an insulator feature with the band gap of 1.65 eV, and its density of state (DOS) implies that this gap arises from splitting 3d-electron of Fe.
Simple Investigation on the Optical Properties of Carbon Nanodots Using Lasers and a Lux Meter Febriani Febriani; Athi' Nur Auliati Rahmah; Bian Itsna Ashfa Al Ashfiya; Juli Astono; Wipsar Sunu Brams Dwandaru
Jurnal Fisika dan Aplikasinya Vol 18, No 1 (2022)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v18i1.11005

Abstract

Carbon nanodots (Cdots) have excellent optical properties. This study aims to investigate scattering and absorption of Cdots via simple exposure of ultraviolet (UV)/violet, red, and green lasers. The experiment was conducted by preparing the Cdots from cajuput oil distillation wastes as the precursor. The solid wastes were dried under the sun, grounded into powder, filtered, and carbonized inside an oven at 250 oC for one hour. The carbonized powder was then mixed with distilled water, left for a night, and then filtered again so that the Cdots solution was obtained. Here, the mass of the precursor was varied. The Cdots samples were characterized using ultraviolet-visible (UV-Vis) and photoluminescence (PL) spectroscopies, and also particle size analyzer (PSA). The lasers were directly exposed to the Cdots samples. A digital lux-meter was used to measure the intensity of the lasers transmitted from the sample. The angle of the lux-meter was varied on a circular track. The sample was on the center of the track. The UV-Vis characterization showed two peaks at 217 nm and 270 nm, and a tail extending to the visible region. The PL characterization showed an intensity peak at 509.57 nm, which confirms the cyan luminescence of the Cdots. The PSA characterization indicated that the size of the Cdots was 1.04 nm. Moreover, at an angle of 0o, the UV wavelength was strongly absorbed by the Cdots in accordance with the UV-Vis characterization result. The intensity of the green laser also dominates as it was less absorbed and strongly scattered by the Cdots.
The Influence of Humidity-Control Addition on Electrospinning System for Nanofiber Formation Diky Anggoro; M Rizki Romadhoni; Imam Muhlas; Iim Fatimah
Jurnal Fisika dan Aplikasinya Vol 18, No 1 (2022)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v18i1.11659

Abstract

This research was conducted to determine the effect of humidity control system and collector rotational speed on electrospinning during PVA nanofiber fabrication. The humidity control system is controlled by Arduino Uno and the actuator is an air pump, and modifications are made to the air pump by adding silica gel as a more optimal humidity reducing agent. A 12 V DC-motor and L293D driver are used to control the direction and speed of rotation of the collector. The collector speed control uses the principle of Pulse Width Modulation (PWM). The humidity control system that has been made has an accuracy rate of more than 88%, and the lowest relative humidity achieved is 30%. The collector control system that has been made has an accuracy rate of more than 95%, and the lowest rotational speed is 125 RPM. Carbon nanofiber was successfully fabricated with an average diameter distribution of 43.4 nm and 79.2 nm at 30% and 40% humidity, respectively.
Effect of Lanthanum Substitution on the Structure and Conductivity of LNMC Samples as Battery Cathodes Maya Puspitasari Izaak; Y. E. Gunanto; H. Sitompul; Y. Purwamargapratala
Jurnal Fisika dan Aplikasinya Vol 18, No 1 (2022)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v18i1.10902

Abstract

Lithium-Nickel-Manganese-Cobalt (LNMC) is one of the most successful types of lithium-ion batteries in the market. This battery is a combination of three main metals, nickel, manganese, and cobalt, with relatively the same composition. Measurements was performed on three LMNC materials combined with La composites to reduce the toxicity level of the Cobalt. The purpose of this research is to synthesize and characterize LMNC materials with certain La combinations, thus it is expected to be able to be used as battery cathode. Characterization of materials was carried out using XRD, SEM, and LCR-meter. In this study, we succeed in synthesizing and characterizing LMNC materials with a size of about 150-750 nm. The LCR-meter characterization found conductivity values of approximately 1.06×10−3, 7.07×1010−4, and 4.05×1010−3 S/cm at 100 Hz, 2.29×1010−3, 2.56×1010−3, and 1.34×1010−2 S/cm at 2.5 MHz, 2.74×1010−3, 3.04×1010−3, and 1.51×1010−2 S/cm at 5 MHz for La dopping with x = 0.01, 0.03, and 0.05, respectively. The La substitution increases the conductivity value and reduces the particle size to nanoscale.

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