cover
Filter by Year
Natural B
Published by Universitas Brawijaya
Anda dapat mengakses artikel-artikel hasil penelitian khususnya bidang lingkungan dan kesehatan. Untuk informasi lebih lanjut, silakan menghubungi redaksi jurnal.
Articles
184
Articles
The Efffect of Wave Sound at Frequency 3 kHz - 4 kHz on Logawa Rice Resistance to Rice Lices

Nadliroh, Kuni

Natural B Vol 4, No 3 (2018)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (185.594 KB)

Abstract

Rice lice is one type of pest that attacks rice, the presence of rice lice can damage the content of rice, rice form and color of rice. Rice that is exposed to rice lice pests will easily fragile and turn into powder and the color of the rice turns yellowish. Innovation is needed to reduce the population of rice lice in the storage phase, so this study aims to determine the effect of sound waves of 3 KHz to 4 KHz frequency on the resistance of logawa varieties to rice lice, in this study the rice plants given the treatment of sound waves of 3 KHz frequency until 4 KHz and without sound waves as controls. Giving of sound waves is done every day from 06.00 to 09.00.

Effect of Stirring Speed on Characteristics of Fe3O4 Nanoparticles Coated with Polyvinyl Alcohol and Glutaldehyde as a Crosslinker

Rahayu, Lale Budi Hutami, Wulandari, Ika Oktavia, Santjojo, Djoko Harry, Sabarudin, Akhmad

Natural B Vol 4, No 3 (2018)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (719.131 KB)

Abstract

Research on Fe3O4 nanoparticles is mostly done because of the unique nature of Fe3O4 which has magnetic properties, non-toxic, biocompatible and easily degraded so it is interesting to investigate as a drug delivery system. This nanoparticles were successfully synthesized by coprecipitation method with variations of stirring rate were 180 rpm (sample A), 250 rpm (sample B) and 320 rpm (sample C). FTIR analysis of Fe3O4 nanoparticles, was absorption at ~585 cm-1 for samples A and B showing the presence of Fe-O magnetite bond and absorption at ~623 cm-1 which were not very sharp for maghemite. However the sample B, only absorption at ~623 cm-1 which is sharp for maghemite (γ-Fe2O3) because of Fe2O3 cubic is not formed. SEM analysis did not show significant morphological differences in velocity variation. From XRD analysis known that the crystal size for samples A and B respectively of 6.4192 nm and 9.5513 nm for sample C could not be calculated because of many iron oxide phases present in it, so it is difficult to find FWHM. ESR analysis of nanoparticle samples shown Fe3O4 properties were ferromagnetic.

The Estimate of Instantaneous Solar Radiation Intensity Using Energy Conversion Method

Saroja, Gancang, Nuriyah, Lailatin, Widodo, Chomsin S, Novanata, M. F.

Natural B Vol 4, No 3 (2018)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (416.252 KB)

Abstract

The intensity of solar radiation provides information of amount energi that is transferred by the sun in a unit time. The information is used in many sectors for designing and assembling systems with solar energi sources. The measurement of the intensity of solar radiation directly requires a complex set of tools and procedures. This study aims to provide an estimate of instantaneous solar radiation by using energi conversion methods. The working principle of the method used is to capture the flux of solar radiation with a piece of black copper plates and then extract the energi into the water medium through direct contact of the water-copper plates. The increase of fluid temperatur is measured as a function of the time duration of radiation exposure. The radiation intensity value is obtained from derivation of the gradient value of the increasing temperatur. The results show that the energi conversion method gives the radiation intensity value matching the radiation intensity value based on the calculation of astronomical formulation. In the location of the experiment, at noon, the energi conversion method gives an instantaneous solar radiation intensity of 1149, 63 W/m2 with a difference of 0.59% with the calculation result of the astronomical formula.

Fourier Integral Implementation to Obtain the Velocity Signal and Displacement Signal from Digital Data of MEMS Accelerometer Sensor

Wasis, Wasis

Natural B Vol 4, No 3 (2018)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (1154.262 KB)

Abstract

This paper discusses and implements a simple technique to obtain the velocity and the displacement signals from the digital data of the MEMS accelerometer sensor, which is an acceleration signal. The method used is a numerical integral, i.e. discrete Fourier integral. Technically, the digital signal data from the MEMS accelerometer sensor is converted from time domain to frequency domain by using Discrete Fourier Transform (DFT). In the frequency domain, the acceleration signal component is integrated once to obtain its velocity components, and is integrated twice to obtain its displacement component. Furthermore, Invers Discrete Fourier Transform (IDFT) is performed to obtain the form of velocity and displacement signals in time domain. The application of these theories and methods gives quite good results, especially for low frequency signals recorded at high sampling rates.

Study of Thermal Neutron Flux and Generated Energy from Linac using CR-39 Detector in Liquid Medium

Widyanti, Kurnia Nur, Widodo, Chomsin S., Bunawas, Bunawas

Natural B Vol 4, No 3 (2018)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (574.238 KB)

Abstract

Linac surgery is required in radiotherapy activities. However, if Linac operated more than 8 MV can cause additional radiation of neutrons, as well as triggers forming secondary cancer. The study was conducted to determine the distribution of thermal neutron flux and energy responses on the trace. One method to detect neutrons is to use a nuclear trace detector. Measurements were made using a CR-39 detector coated with a Boron radiator. A number of detectors were placed on the surface of the sphere and entered into a 30×30×30 cm3 fantom. Irradiation is done by placing fantom under Linac gantry with 100cm SSD distance. After irradiation, then etching. The results of the measurements showed that the distribution of thermal neutron fluxes spread in all directions. Linac 10 MV neutron flux value varies, starting at 0° of 1,637×103 n/cm2.s and decrease at 135°of 1.285×103 n/cm2s. The highest Linac 15 MV at detector position 0° of 10.723x104 n/cm2.s and decreased at 135° of 5.142x104 n/cm2s. This proves that the farther from the source the less the thermal neutron flux value due to the collision process. While Linac 10 MV and 15 MV produce range of diameter ranging from 8.21-16.75 (μm) and 9.21-17.45 (μm), with energy response value 0.5-3.5 MeV. The larger the energy response, the smaller the diameter and vice versa, this is due to the effect of penetration on the depth of the distance resulting in smaller track.

Study of Stearic Acid Layer (SA) Microstructure on Surface Quartz Crystal Microbalance (QCM) Sensors

Nurramdaniyah, Nurramdaniyah, Padega, Masdiana, Santjojo, Djoko Herry, Sakti, Setyawan P., Masruroh, Masruroh

Natural B Vol 4, No 2 (2017)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (360.677 KB)

Abstract

In the development of QCM-based biosensor sensors, the sensor surface is a very important part because it determine how the surface interacting with its environment especially during the immobilization of biomolecules process. In the utilization of QCM as biomolecule detecting biosensor, it is necessary to coat the polymer material on the surface of QCM. A stearic acid layer is used as an immobilization matrix layer because stearic acid has both polar and non polar properties so it can interact with biomolecules. The stearic acid layer is deposited on the polystyrene surface using a vacuum evaporation method. A study of the microstructure of the stearic acid coating was conducted to determine the possibility of the deposited stearic acid layer used as the matrix layer. In this research, microstructural study of layers of the stearic acid by using Scanning Electron Microscope (SEM) was carried out to find out the surface morphology of stearic acid. X-Ray Difraction (XRD) measurements were conducted to identify the crystal structure of stearic acid while Fourier Transform Infrared (FTIR) measurements were used to determine the stearic acid functional group. The Scanning Electron Microscope (SEM) results show the surface of the cavity and pore layers of the polystyrene layer was coated with white fibers homogeneously deposited on the surface of QCM / Polystyrene. Furthermore, the X-Ray Difraction (XRD) results showing a spectrum peak at an angle of 2q = 26,66° indicates the existence of stearic acid crystals. Whereas, the measurement results of the Fourier Transform Infrared (FTIR) indicate the appearance of C-H functional groups at a wavelength value of 3600-2600 cm-1 which indicates the functionality of the stearic acid layer. 

The Effect of Smoking Behavior in the Human Population Growth of Lung Cancer Patients

Wardah, Lu’luul, Trisilowati, Trisilowati, Kusumawinahyu, Wuryansari Muharini

Natural B Vol 4, No 2 (2017)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (471.487 KB)

Abstract

This article discusses a model of lung cancer as the effect of smoking behavior on both active and passive smoker. There are four subpopulations in this model, namely susceptible subpopulation, active smoker subpopulation, passive smoker subpopulation, and subpopulation of lung cancer.  Dynamical analysis is conducted to determine the equilibrium point, existence condition for equilibrium point, and analyze their stability. Based on analysis result, there are three equilibrium points. First equilibrium point shows that all subpopulations extinct. Second equilibrium point shows that only susceptible subpopulation can survive, and the last equilibrium point shows that all subpopulations can survive. First equilibrium point always exists while the others exist under certain condition. The stability of first equilibrium point can be reached when the intrinsic growth rate is less than the death rate. Whereas, the others equilibrium points will be stable under certain condition. Numerical simulation is performed to illustrate the analysis result. It is shown that numerical results are in accordance with analysis result. These numerical simulations also indicate that the rate of passive smoker plays important role in the growth rate of lung cancer.

Analysis of Voltage Difference Characteristics of Albumin Membranes and Vitelin Membranes of Chicken Eggs through Diazinon Effects

Jauharah, Wira Dian, Santoso, Didik Rahadi, Juswono, Unggul P.

Natural B Vol 4, No 2 (2017)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (196.017 KB)

Abstract

Cells are the most important structural and functional part of any organism. Cells are protected by cell membranes that envelop cells, and separate cells with their environment. The effectiveness of the work of a cell membrane can be disrupted for various reasons, one of which is pesticide contamination. Pesticides in cells can damage cell metabolism or cell membrane permeability. Therefore, this study aims to determine how big the effect of diazinon insecticides on the characteristics of different potential membrane vitelin and membrane albumin chicken egg cells. Measurements were made using the microelectrode connected with the picoscope 5000 series, then the data appears displayed through the PC. The results of membrane potential measurements showed that the greater the concentration of insecticide given, the potential value of chicken egg membrane increased. Potential Differential Values Membrane of eggs with different concentrations ranged in -145 mV - 249 mV on vitelin membrane, and -142,5 mV - 242,5 mV on albumin membrane 

The effectiveness study of SnCl2.2H2O masking on the formation of QCM profile using wet etching technique with KOH solution

Rusly, Tri Andi, Santjojo, D.J. Djoko H., Sakti, Setyawan P., Masruroh, Masruroh

Natural B Vol 4, No 2 (2017)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (364.179 KB)

Abstract

SnCl2.2H2O  has been successfully utilized to produce isotropic profile on the surface of a SiO2 crystall by a wet etching procces. The etching process was carried out by using a 40% KOH solution. In this research, the wet etching method is carried out by optimizing the etch time which was varied for 0,5 hour, 1 hour, 1,5 hour.  The profile was determined by applying a SnCl2.2H2O  on the surface of a QCM. The mask was applied by using a spray coating technique. The SnCl2.2H2O  material was chosen as the masking material because it has a high adhesive property to SiO2, does not react to the KOH etching solution and is corrosion resistance as well as low cost. The etching profile surface results and etch depth (Dz) were determined using topography measurement system (TMS 1200). The etching rate with 40% KOH during etching time of 30 minutes, 60 minutes, 90 minutes were 4.36 μm, 4.56 μm and 5.79 μm respectively. The optimum QCM surface isotropic profile was obtained at the etching rate of 4.56 μm / h by 60 minutes etching. 

Optimization of Pesticide Analysis Method for Diazinon and Chlorantraniliprol Using High Performance Liquid Chromatography (HPLC)

Tea, Marselina Theresia Djue, Sabarudin, Akhmad, Sulistyarti, Hermin

Natural B Vol 4, No 2 (2017)
Publisher : Natural B

Show Abstract | Original Source | Check in Google Scholar | Full PDF (189.885 KB)

Abstract

Methods of obtaining diazinone and chlorantraniliprol in soil samples have been developed. Analytes were extracted using acetonitrile by using an ultrasonic solvent extraction method (USE). The discovery uses high performance liquid chromatography using a UV detector. The optimum conditions for the separation of both pesticides are Acetonitrile composition: Air (60:40), flow rate 0.4 mL / min, and at 220 nm wavelength. The more the amount of acetonitrile in the eluent mixture the faster the retention time in the column. Retention time respectively, chlorantraniliprol 10,525, and diazinon 21,029.