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Spektra: Jurnal Fisika dan Aplikasinya

spektra
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Published by Universitas Negeri Jakarta

ISSN : 25413384 EISSN : 25413392 DOI : -

Core Subject : Science, Engineering,

Aerospace Engineering Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Physics

Arjuna Subject : -

Articles 8 Documents

Search results for , issue "Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019" : 8 Documents clear

THE SPRING VARIATION IN TWO DIMENSIONAL MODELING OF RED BLOOD CELL DEFORMABILITY BASED ON GRANULAR Ismi Yasifa; Sparisoma Viridi
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

The red blood cell membrane has a complex structure and high deformability. Simulation of that complex red blood cell membrane can simpler use granular-based modeling. Red blood cell is modeled consisting of 50 granular particles connected by springs. An i-particle is connected with two of its first nearest particles which are i+1-particle and i-1-particle and with two of its second nearest particles which are i+2-particle and i-2-particle. Each particle has a spring force and forces from internal hydrostatic pressure. Spring force is a product of the spring constant and change of spring length of two particles. Meanwhile, forces of internal hydrostatic pressure is a product of particle diameter and the difference in the outside and inside pressure of red blood cell membrane. In this research, there is variation in spring length and spring constant that can model deformability of three shapes of red blood cell; those are biconcave, ellipse, and circle. This variation in spring length and spring constant for every cell shape in this modeling can also use for other initial cell shapes, which shows that initial cell shapes deform into shape according to variation used.

OPTIMIZATION OF THE USE OF FLY ASH AS AN ADDITIVE PORTLAND COMPOSITE CEMENT (PCC) Leni Rumiyanti; Listiani Listiani; Tika Damayanti
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Research has been carried out on the optimization of the use of Lahat Fly Ash as an Additive Portland Composite Cement (PCC) which aims to determine the optimum conditions for adding Lahat fly ash to produce cement with physical and chemical requirements in accordance with SNI 7064:2014 and discover the ideal composition of cement with fly additions Lahat ash from various cement compositions. The quality analysis in making PCC cement is chemically in the form of Insoluble Residue (IR), Loss of Ignition (LOI), and free lime (FCaO) as well as the quality of physics in the form of Blaine, setting time, and cement mortar compressive strength. The results obtained after the process of making PCC cement with the addition of 14% Lahat fly ash, namely PCC cement in optimum conditions with physical and chemical requirements in accordance with SNI 7064: 2014 where the ideal composition of PCC cement manufacture is 14% Lahat fly ash, clinker 62%, 3% gypsum, 18% limestone, and 3% pozzolans in making PCC cement. Therefore, Lahat fly ash can be used as an alternative mixture in making PCC cement.

FLUIDIZATION OF A BED OF SOLID PARTICLES IN A TWO DIMENSIONAL VERTICAL BOX Aufa Numan Fadhilah Rudiawan; Kurnia Novita Sari; Hirofumi Notsu; Sparisoma Viridi
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Simulation of fluidization of a bed of solid particles in a two-dimensional box is performed using molecular dynamics methods by assuming that superposition of buoyant, gravitational, viscous, collision force will make the particle to move in two dimensions. Two different fluid type is used in this simulation, i.e., gas and liquid fluid. By increasing the fluid velocity from small to high, then minimum fluidization condition reached. As a result, fluidization of alumina particle with liquid fluid has a minimum fluidization velocity lower than gas fluid.

FRUIT SWEETNESS CHARACTERIZATION USING IMPEDANCE SPECTROSCOPY METHOD Rahmondia N Setiadi; Lazuardi Umar
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

The processing of agricultural products requires technology implementation to increase its production. One way of this technology implementation to increase the production is fruit sweetness measurement, which can be used as a sorting tool of fruit products. The sorting process using this tool can be done with easier way compare than the manual and destructive test. The fruit sweetness is composed of a mixture of sweet molecules fructose, glucose, and sucrose. The measurements of these molecules are usually done with four-point probe and use dc current. In this study, a fruit sweetness characterization using impedance spectroscopy method has been developed and realized, which uses an ac current. By using this method, fruit sweetness level can be characterized based on the impedance measurement on the flesh of a test fruit based on its dielectric properties. The obtained characterization results show that the fruit sweetness level can be measured by the impedance measurement. The obtained impedance is proportional to the concentration of the sweet molecule glucose. This method can characterize the fruit sweetness well and agrees with the calibration result. Therefore, this method can be used to increase agricultural products.

BIOSENSOR SYSTEM DESIGN FOR DISSOLVED OXYGEN MEASUREMENT USING CURRENT MIRROR CIRCUIT Lazuardi Umar; Rahmondia N Setiadi; Arfianti; Tetty M Linda
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

A biosensor system using a current mirror circuit has been designed and characterized. Biosensor system usually implements an amperometric circuit such as a trans-impedance topology to measure current flowing in the solution due to the contained dissolved oxygen. The trans-impedance circuit implemented for the biosensor has some drawbacks and disadvantages. The implementation of this circuit exhibits rather high noise, besides the impracticality of the power supply used due to bipolar voltage need to allow negative voltage output. In this paper, a classical current mirror circuit is used to convert the flowing current in the solution. The use of the classical current mirror circuit is aimed to obtain lower noise level, besides the easiness in providing the power supply for the system, since the circuit consists only of small number of active components and does not need a bipolar power supply. The measurement is performed utilizing an algae species as a bio-receptor for the measured dissolved oxygen. By utilizing this circuit, the biosensor measurement system can be optimized with better precision and noise performance. Consequently, the dissolved oxygen measurements can be improved and achieve good results. Besides, the system can detect the changes in dissolved oxygen due to the photosynthetic process of the algae.

MULTI-CHANNEL FRY COUNTER DESIGN USING OPTOCOUPLER SENSOR Lazuardi Umar; Yanuar Hamzah; Rahmondia N Setiadi
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

This paper describes a design of a fry counter intended to be used by consumption fish farmer. Along this time, almost all the fry counting processes are counted by manual, which is done by human. It is requiring much energy and needs high concentration; thus, can cause a high mental and emotional exhaustion for the fry counting worker. Besides that, the human capability and capacity for counting the are limited to a low number. A fry counter design in this study utilizes a multi-channel optocoupler sensor to increase the counting capacity. The multi-channel fry counter counting system is developed as a solution to a limited capacity of available fry counter. This design uses an input signal extender system for the sensor. The design is based on the interrupt combiner to accommodate multi-channel sensor used. Besides, the transmitter beam's angle is adjusted to deal with the deflection due to water surface. From the experiment, multi-channel sensor can be implemented and high accuracy level could be obtained on the counting and channel number detection, therefore, this design can be implemented and could help farmers to increase the production capacity of consuming fish.

FRONT MATTER SPEKTRA VOLUME 4 ISSUE 2, AUGUST 2019 Editor Spektra
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

BACK MATTER SPEKTRA VOLUME 4 ISSUE 2, AUGUST 2019 Editor Spektra
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 2 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 2, August 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Dki jakarta

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