Pengaruh waktu milling terhadap Sifat mikro struktur dan magnet dari NdFeB dengan proses Wet dan Dry milling

Making of magnets from NdFeB flakes by Wet and dry milling to determine the microstructure, physical and magnetic properties of the milling time variation is 16, 24, and 48 hours. The milling powder is then analysed to determine the particle size with PSA and XRD to determine the phase formed. Then the compacting process with isotropy printing for making pellet test samples with a pressure of 7 tons for 2 minutes. Then the pellet sample, given annealing temperature with a variation of 150 and 170 ̊C, then a measurement of magnetic properties with a Gauss Meter. The results obtained by the smallest optimum particle size with 48 hours of milling time at a diameter of 90% 4.7 μm, while the results of dry milling at a diameter of 90% amounted to 60.85 μm. The best method to get the smallest particle size is the Wet milling method. XRD results with Wet and Dry milling phases that appear only Nd2Fe14B phase. As milling time increases, the resulting density increases. The largest magnetic flux testing with dry milling method with 48 hours of milling time for temperatures 170 ̊C temperature obtained 468.5 Gauss and the addition of annealing temperature the magnetic properties of the material is getting better.

Analisis Perhitungan Gaya Berat pada Tongkat Gayung Lipat untuk Mengetahui Efektifitas Pengungkit Jenis Tiga

Tongkat Gayung Lipat is a tool initiated by a PKM-KC team at the University of Education of Indonesia. The Tongkat Gayung Lipat is a tool that can help humans' outdoor activities. It has four main functions such as a mountain climbing tool, a container for taking water both far or near located, a flashlight in the stick handle serves as a lighting tool, and a knife in the stick handle serves cutting objects. Human needs when going on vacation and the limitations of the water dipper in tourist attractions are the reasons for making this tool. This tool was initiated to make it easier for people to do activities in the bathroom and do other activities outdoor (indoor and outdoor). Thus, to see the effectiveness of the tool, a trial was carried out by considering the load and human strength when lifting water. The calculation carried out using the third type of lever of physics laws approach which can provide a precise calculation of the effectiveness of objects. The analysis was carried out using the fourth lever type of physics law approach by calculated gravity, mass, and force. The result of the calculation was there is three comparisons of gravity. They are 23.6 N, 23.3 N, and 12.03 N. With these results, it is necessary to analyze the effectiveness of the Tongkat Gayung Lipat.

Rancang Bangun Alat Pengukur Suhu Real Time Laboratorium Menggunakan Protokol MQTT Berbasis Internet of Things

The stable temperature in the laboratories is the major requirement for ensuring safety at work. The changes in the temperature which are oftentimes caused by precisely unrecognized factor may provide hazardous impacts on humans who are working in such place. Similar researches were conducted; however, they did not use NodeMCU as a microcontroller and MQTT protocol. This study tried to build a real-time temperature observation system using MQTT protocol based on the Internet of Things which has a fast delivery speed message. The temperature and humidity were captured by using DHT22 sensor that were then stored in database for one month. The result showed that the temperature change of the laboratory could be rapidly detected through the tests process on a certain heat-produced device. It could be analyzed periodically using the real-time application so that the impact of temperature rise could be detected quickly.

PENGARUH PENAMBAHAN CO-DOPING Mg/La TERHADAP KARAKTERISASI TiO2 SEBAGAI FOTOELEKTRODA

The effect of Mg/La co-doping addition on the caracteristics of TiO2 as photoelectrode have been studied. This study aims to investigate the effect of Mg/La co-doping concentration on the characteristics of TiO2. This study aims investigate the effect of Mg/La co-doping concentration on the characteristics of TiO2. Mg/La was varied from 0% mol, 0.4 / 0.6% mol, and 0.6 / 0.4% mol. Synthesis of TiO2 co-doping Mg/La was done by sol gel method. The resulting of powder pure TiO2 and co-doping Mg/La was made to paste, and was deposited on a glass substrate with a size of 2.5 x 2.5 cm and sintered at 600°C for 1 hour. Mg / La co-doped TiO2 layers were characterized using XRD, UV-Vis, and FTIR spectrometers. The results showed that TiO2 was the mos dominan phase appeared in pure TiO2 sample. The phase of MgO, MgTiO3, Mg2TiO4, and La2O3 were found in Mg/La co-doped TiO2 samples. The crystal size of Mg/La co-doped TiO2 was varied from 8.85 to 7.70 nm. In this research, we obtained that the energy gap was varied from 3.52 to 3.5 eV depent on co-dopant concentration. FTIR measurement showed groups of Ti-O, Ti-O-Ti, Ti-O-O, and H-O.

Pengukuran Modulus Geser Baja Menggunakan Analisis Osilasi Pegas-Massa

A steel shear modulus measurement has been conducted using spring-mass oscillation analysis. The purpose of this study is to determine whether the spring-mass oscillation analysis method can measure the shear modulus of the steel. In this study, springs that are used are made of steel with a spring radius of 7.86 mm, a spring wire diameter of 0.817 mm and there is no distance between the coil springs. The length of the spring is varied 7 times, i.e., 4.75 cm, 5.36 cm, 5.89 cm, 6.81 cm, 8.53 cm, 9.44 cm, and 10.87 cm. The spring radius and the diameter of the spring wire are measured using a micrometer screw, while the spring length is determined using image analysis using the Logger Pro program. The spring constant is determined from the equation of the results of the position graph fitting (x) with respect to time (t) load on the oscillating spring-mass system. The value of the shear modulus can be determined from the constants on the graph of the relationship of the spring constant to the spring length following the equation from Sommerfeld. The research measures the shear modulus is 1.24 GPa

Kajian Impelementasi Quality Control Faktor Bright Band dan Atenuasi Radar Cuaca C-Band

Weather radars have several limitations there are bright band echoes and attenuation of electromagnetic wave from radar’s beam. The purpose of this research is to conduct an analysis respect to the result of quality control from both of the limitations in 2019 which divide into four case study. Freezing level height of radiosonde used for support the identification activity of BBC phenomena. The result of BBC can reduce the BBE patterns however, it unable to function optimally in reducing all parts of the BBE patterns. Rainfall attenuation correction that have been done shows various results, either quantitatively or qualitatively. Attenuation correction is able to increase the rainfall value in product image SRI and PAC qualitatively. Quantitative analysis shows that the r and MAE values after attenuation correction of hourly rainfall have a good value besides that the attenuation correction in daily rainfall data is able to improve the estimate by 62.5%.

Pengaruh Tegangan Tabung terhadap Kualitas Citra pada Pemeriksaan Computed Tomography Kepala menggunakan Iterative Reconstruction

Iterative reconstruction can optimize radiation dose and improve image quality on CT scan. This research method is quantitative analytic with the analysis of the results of the head CT examination parameters associated with image quality to changes in variations of 80 kV, 100 kV, 120 kV with the use of iterative reconstruction. Image quality measurements are the Hounsfield Unit (HU) value, standard deviation, and Signal to Noise Ratio (SNR) using Radiant Viewers. Effective dose measurement using the Dose Length Product (DLP). Then perform the Kruskal Wallis test to find out whether there is an effect of tube voltage and Iterative Reconstruction on the SNR value using IBM SPSS version 24. The results image quality of the HU value increase due to changes in the kV value, but the value does not change significantly when the iDose changes, for the standard The deviation has decreased due to changes in kV, but the value of the value does not experience a significant change at the time of change in iDose, while SNR increases due to changes in kV value and changes in iDose. The percentage ratio of the effective dose in the use of standard kV with 80 kV decreased radiation dose by 62%, while at 100 kV there was a decrease of 25%, and the use of 120 kV experienced an increase of 25%. The results of the Kruskal Wallis test p-value <0.001, therefore it can be concluded that there is a difference in the SNR image quality at each change in iDose and kV parameters.

Pengaruh Molaritas dalam Teknik Spray terhadap Performa Fotodetektor Berbasis ZnO

ZnO:Fe thin films has been successfully carried out by a simple spray pyrolysis method. The thin film was grown on ITO (Indium Tin Oxide) substrate with a metal-semiconductor-metal (MSM) structure. ZnO:Fe thin film characters as photodetector application include morphological structure, and electrical properties. SEM image results show the molarity difference can affect the particle size. The Current-Voltage (I-V) characterization shows that different solvent effects and molarity give different sensitivity. Sample ZnO:Fe 0.5M Ethanol has the highest sensitivity compared to other samples because it has a fairly low current and high bright current.

Sintesis Ferroelektrik BaZrxTi1-xO3 Dengan Variasi Zirkonium Terhadap Struktur Kristal dan Konstanta Dielektrik

This study aims to determine influence addition Zr against the crystal structure and dielectric constant; and to know the influence of variations temperature sintering on addition mole Zr. Barium Zirconium Titanate (BaZrxTi1-xO3) have been made with variation zirconium (Zr) 1%, 5%, 10%, and 20% by solid state reaction method, that is blanded BaTiO3, TiO2 and ZrO2 powder. BaZrxTi1-xO3 powder is printed with die pressing and press hidrolik, then the samples were sintered by furnace at 900oC and 1000oC with holding time 2 hours. Characterization of samples use X-Ray Diffraction and Resistance Capacitance Inductance (RCL meter). Based on result obtained, the larger Zr content cause dielectric constant decreasing because crystal structure have been change from tetragonal (Zr = 1% and 5%) to cubic (Zr = 10% and 20%). The result from X-Ray Diffraction already match with data base ICDD no#360019. Measurement of dielectric constant (K) performed in the frequency range 1 kHz to 100 kHz and the highest value at Zr content 1%, because The dielectric constant decreasing with the larger Zr content. The maximum dielectric constant is obtained at mol Zr 5% and sintering temperature 1000oC, that is 150. The minimum dielectric constant is obtained at mol Zr 20% and sintering temperature 900oC, that is 62.

Analisis Pola Struktur Kalsium Karbonat (CaCO3) Pada Cangkang Kerang Darah (Anadara granosa) Di Bukit Kerang Kabupaten Aceh Tamiang

Characterization of material on cockle shell has been wiped out the shells hills of the Bendahara district of Aceh Tamiang district, with the aim of knowing the basic content and diffraction patterns of the cockle shell to plain CaCO3 aragonite. The research method begins with sampling the cockle shell from the Kerang hill. Firstly, preparation cockle shell. Then, characterized by X-Ray Fluorescence (XRF) examining to work out the basic content within the cockle shell, then doing Scanning Microscopy Energy Dispersive X-Ray (SEM-EDX), and X-ray diffraction ( XRD) testing. The characterization leads to XRF testing showed that the content of the constituent elements of the CaCO3 compound was dominated by CaO of 98.93% at station I and at station II, CaO was obtained the maximum amount as 98.73%. In SEM analysis, the cockle shell have a rod-like morphological structure within the sort of aragonite crystals. The results of EDX at station I, obtained CaO elements is 58.18% and at station II CaO is 36.76%. The results of XRD analysis, the cockle shell have an aragonite phase with an orthorombic crystal structure. the very best phase that appears at 2θ at station I is 26,220, and station II is 26,280.