Spektra: Jurnal Fisika dan Aplikasinya
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254 research outputs found
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ROLE OF ISOVECTOR-ISOSCALAR COUPLING ON CHARGE RADIUS OF HEAVY AND SUPERHEAVY NUCLEI
Full text linkWe have investigated the effect of the isovector-isoscalar coupling on the finite nuclei and nuclear matter properties, the neutron skin thickness of 208Pb, and the charge radius on heavy and superheavy nuclei calculated by the relativistic mean-field (RMF) model. In this work, we generates two parameter sets, i.e., PTE16 and PTE31. The numbers 16 and 31 denote the isovector-isoscalar coupling terms, while T and E denote the tensor coupling and electromagnetic exchange terms, respectively. We found that PTE16 and PTE31 are compatible with the constraints obtained by R. Essick, et al., arXiv: 2102.10074v1 [nucl-th] (2021). We also found that the increase of the isovector-isoscalar coupling terms gives a significant effect on the binding energy and the charge radius on heavy nuclei except for the charge radius of 208Pb. Increased of the isovector-isoscalar coupling terms make the values of charge radius prediction increase too, but vice versa for the neutron skin thickness and nuclear matter prediction. PTE31 yields symmetry energy J = 31.521 MeV, slope L = 57.643 MeV, and neutron skin thickness = 0.21419 fm. While the β2 correction (for deform nuclei) does not always give a significant effect on the charge radius
IMPLEMENTATION OF TRS-398 PROTOCOL IN ROUTINE CALIBRATION OF LINAC BY DETERMINATION OF SLAB PHANTOM ON WATER PHANTOM CORRECTION FACTOR
Full text linkThe water phantom is used for LINAC calibration to measure absorbed dose radiation. Practically, it requires a long preparation time and is considered less efficient. To increase efficiency, the medical physics team in a hospital uses slab phantom as the calibration tool. Consequently, the correction factor is crucial to define the equivalence of the absorbed doses resulted from slab phantom. The absorbed dose measurement was performed according to the IAEA TRS-398 dosimetry protocol with a cylindrical ionization chamber detector for 6 MV photon beam and electron beams from Elekta Synergy Platform 154029 LINAC with 6 MeV, 8 MeV, 10 MeV, and 12 MeV energy variations. The field size for slab and water phantom is 30 cm x 30 cm x 30 cm. Based on the TRS-398 protocol, the correction factor of the slab phantom calculated based on absolute dosimetry for 6 MV photons beam, the electron beam of 6 MeV, 8 MeV, 10 MeV, and 12 MeV are 1.0018; 0.9995; 0.9979; 1.0041 and 1.0068, respectively. As a result, the absorbed dose radiation measured by the calibrated slab phantom using the resulted correction factor has an equivalent amount to the water phantom
INTRAVENOUS INFUSION DOSING SYSTEM FOR VOLUME CONTROL BASED ON SIGNAL PERIODIC MEASUREMENT
Full text linkIntravenous fluid therapy is a commonly used treatment modality that is used in the treatment of hospitalized patients. Intravenous flow rates are often controlled by counting the number of fluid drops in a drip chamber while adjusting the intravenous line with a watch. In this research, an intravenous infusion dosing system was designed based on periodic signal measurement using a pair of light couplers consisting of a transmitter and a receiver. The transmitter is built using an infrared LED (BPV10NF), while the receiver uses an infrared photodiode detector (BPW34). The infusion droplet will pass a slit between the two coupler components and interrupt the light transmission from the transmitter to the receiver, which will affect the current through the photodiode and change the output status of the circuits. The parameters obtained from this circuit signal are droplet frequency from 1 Hz to 10 Hz and droplet sizes 0.05 ml and 0.0167 ml. The resulting output signal is in the form of pulses due to the interruption of the droplet when it passes through the optocoupler. The droplet frequency is calculated based on the period between adjacent droplets, while the droplet size can be measured based on the width of the resulting pulse. For the droplet measurement process, variations of the droplet period and the number of droplets per ml were carried out. The droplet period is regulated by manually adjusting the aperture of the infusion droplet outlet faucet. In contrast, the droplet size is controlled by two types of infusion devices with 20 drops/ml and 60 drops/ml specifications. The experimental results can be used to develop a system response that detects changes in period and droplet size
THE ANALYSIS OF SOUND TRANSMISSION LOSS ON LAMINATED GLASS
Full text linkLaminated glass is one type of glass that is commonly used for sound insulation (walls or doors). Tests related to the ability of insulating glass in Indonesia are still sporadic. One of the places to do this test is the SNSU BSN Lab. This Lab has a function to perform sound insulation level measurements commonly known as Sound Transmission Class (STC) and maintain to trace the ability of acoustic measurements. This paper describes the characteristics of Sound Transmission Loss (STL) of 12mm laminated tempered glass. The sample measurement method refers to ISO 10140-1 using two chambers (source and receiver room). Based on the study results, it was found that the laminated tempered glass sample was not good at reducing sound at low frequencies and tended to be good at high frequencies
THE DENSITY FUNCTIONAL THEORY STUDY OF Li-ION DIFFUSION IN Na-DOPED Li4Ti5O12 AS LITHIUM-ION BATTERY ANODE
Full text linkSpinel phase lithium titanate (Li4Ti5O12 or LTO) has been studied as an alternative anode material with a “zero-strain” characteristic structure to improve safety, cycling stability, and rate performance. LTO offers stable Li-ion diffusion at a higher charge-discharge rate without noticeable structural change. However, LTO exhibits low electronic conductivity and low Li-ion diffusion compared to graphite-based anode materials, limiting its rate capability. In this study, we investigate the impact of Na atom doping on the diffusion rate in the Li4Ti5O12 (LTO) spinel phase using the density functional theory (DFT). Based on the nudged elastic band (NEB) calculation, we obtain the energy barrier values and each diffusion pathway, with barrier energy varying about 0.3~0.4 eV and affecting the value of the diffusion constant obtained. The study reveals the role of Na atom doping in the lithium-ion diffusion in NaxLi4-xTi5O12 for battery anode material. 
SMART SEAL BASE ON WIFI USING WEB SERVICE PHP
Full text linkTechnological developments, especially in the IoT (Internet of Things), play a significant role in various fields. In addition to achieving a modern and efficient work environment, IoT can also play a role in the security sector, which has now become a significant need. One of the roles of IoT in the security sector is that it can be applied to calibrated TMWE (Measuring, Dosing, Weighing, and Equipment). So that it can guarantee the correctness of the measurement results from the TMWE, continuous monitoring can be carried out so that fraud does not occur. One of the innovations in this regard is the smart seal. The use of smart seals is prioritized for fixed TMWE, which is vulnerable to theft and breaches. This system is designed based on IoT, which is integrated with cloud services and GPS systems that allow the use of web-based applications for online monitoring of seal conditions by users. Data from the seal will be sent to the server via wifi network and stored in a database, to be displayed in web service with a user, admin, and signer access. In addition to providing information to users about the seal’s location, the use of the GPS also aims to make it easier for admins to detect the seal’s location in the event of a violation
MAGNETIC FIELD-DEPENDENT ELECTRIC CURRENT ON A PERIODIC POLY(DA)-POLY(DT) DNA MOLECULE STRUCTURE
Full text linkAn electric current flowing on the Poly(dA)-poly(dT) DNA molecule structure has been calculated. The current was calculated from transmission probabilities by employing Landauer-Buttiker formalism. Green’s function technique has been used for obtaining the transmission probabilities. The DNA molecule structure was modeled within the tight-binding Hamiltonian model approach. The model takes into account electron hopping parameters which are dependent on the magnetic field as well as the electric field. The presence of a magnetic field causes the Peierls phase factor on the electron hopping parameters. The calculation results at low electric voltages show that after decreasing, the electric current oscillates with the magnetic field. However, at higher electric voltages, the electric current is increasing and oscillates with the magnetic field
