Coffee Bean Grade Determination Based on Image Parameter

Quality standard for coffee as an agriculture commodity in Indonesia uses defect system which is regulated in Standar Nasional Indonesia (SNI) for coffee bean, No: 01-2907-1999. In the Defect System standard, coffee bean is classified into six grades, from grade I to grade VI depending on the number of defect found in the coffee bean. Accuracy of this method heavily depends on the experience and the expertise of the human operators. The objective of the research is to develop a system to determine the coffee bean grading based on SNI No: 01-2907-1999. A visual sensor, a webcam connected to a computer, was used for image acquisition of coffee bean image samples, which were placed under uniform illumination of 414.5+2.9 lux. The computer performs feature extraction from parameters of coffee bean image samples in the term of texture (energy, entropy, contrast, homogeneity) and color (R mean, G mean, and B mean) and determines the grade of coffee bean based on the image parameters by implementing neural network algorithm. The accuracy of system testing for the coffee beans of grade I, II, III, IVA, IVB, V, and VI have the value of 100, 80, 60, 40, 100, 40, and 100%, respectively

Growth of ZnS:Ag:Cu Thin Film Deposited on Glass Substrates using Thermal Evaporation Technique for Alpha-photovoltaic

This paper presents the research on the growth of ZnS:Ag:Cu thin film on a glass substrate as a radio-luminescent material. The SRIM/TRIM software is used to determine the optimum thickness based on an energy deposition depth of 5.485 MeV Am 241 alpha radiation source on ZnS:Ag:Cu material. To increase the adhesive strength of the coating, initially, the glass substrate is etched using a plasma glow discharged at 280°C for 15 minutes. Multiple coatings of ZnS:Ag:Cu were  etched on the glass substrate; this was carried out using a thermal evaporation technique to achieve the optimal thickness (based on SRIM/TRIM simulation). The thin film thickness was observed using a scanning electron microscope (SEM). The optical properties of the un-etched, etched glass substrate and thin-film were characterized using UV-Vis spectrometer. Based on SRIM/TRIM simulation, the optimal thickness is 22 mm which can be achieved by coating three times. From optical properties of ZnS:Ag:Cu thin film and after being analysed using Taue plot method, it is found that the energy gap of ZnS:Ag:Cu thin film is 2.48 eV. It can be concluded that the addition of Ag and Cu doped decrease the energy gap of ZnS (3.66 eV)

Optimasi Pembentukan Lapisan Boron P+ pada Permukaan Belakang Sel Surya untuk Peningkatan Efisiensi Sel Surya berbasis Wafer Silikon Monokristal

Efisiensi sel surya dapat ditingkatkan dengan mengurangi rekombinasi pada permukaan belakang dari sel surya. Salah satu strategi yang dapat digunakan untuk mengurangi rekombinasi pada permukaan belakang adalah dengan mengurangi konsentrasi pembawa muatan minoritas di bagian permukaan belakang sel surya. Kondisi ini dapat dicapai dengan membuat lapisan boron p+ pada permukaan belakang sel surya yang memiliki konsentrasi lebih tinggi daripada basis dan memiliki tipe doping yang sama, dikenal sebagai lapisan boron -back surface field (B-BSF). Saat ini berdasarkan kecenderungan eksperimental, didapatkan bahwa peningkatan konsentrasi doping dan ketebalan lapisan B-BSF akan meningkatkan efisiensi sel surya. Akan tetapi, pada proses fabrikasi B-BSF eksperimental, ditemukan bahwa meningkatkan ketebalan lapisan BSF sangat sulit dan meningkatkan biaya. Oleh karena itu diperlukan studi untuk menganalisis sampai batas mana usaha untuk meningkatkan ketebalan lapisan BSF secara eksperimental dapat memberikan peningkatan nilai efisiensi yang memadai untuk digunakan pada industri sel surya di masa depan. Pada penelitian ini telah dilakukan analisis secara simulasi, pengaruh ketebalan dan konsentrasi lapisan boron BSF terhadap efisiensi pada sel surya berbasis wafer silikon monokristal. Simulasi dilakukan menggunakan perangkat lunak PC1D. Simulasi dilakukan pada wafer 300 mikron dengan doping dasar tipe-p 1,50x1016/cm3 dan emitter tipe-n dengan ketebalan 1,56 mikron dan konsentrasi doping 7,5x1018/cm3 yang memiliki efisiensi 16,30%.Hasil simulasi menunjukkan bahwa secara umum semakin tebal lapisan boron p+ dan semakin tinggi konsentrasi dopingnya, efisiensinya akan semakin meningkat. Pengecualian terdapat pada ketebalan lapisan diatas 220 mikron dan konsentrasi diatas 1,26x1019/cm3. Hasil ini sesuai dengan kecenderungan eksperimental dan memprediksikan bahwa kecenderungan ini akan berlanjut sampai nilai ketebalan lapisan BSF yang sangat ekstrim. Akan tetapi ditemukan bahwa laju peningkatan efisiensi terhadap peningkatan ketebalan lapisan BSF mengalami penurunan secara signifikan setelah ditingkatkan melebihi ketebalan 20 mikron. Selanjutnya optimasi dilakukan untuk memaksimalkan efisiensi sel surya terhadap variasi dari ketebalan dan konsentrasi. Ditetapkan tiga pembatas yakni konsentrasi doping, ketebalan lapisan dan peningkatan efisiensi marjinal terhadap peningkatan ketebalan lapisan. Untuk konsentrasi doping NBSF dibatasi 1017/cm3≤NBSF≤1020/cm3 dan ketebalan lapisan WBSF dibatasi sampai 20 mikron. Sebagai pertimbangan kompromi antara usaha untuk peningkatan efisiensi dan kemudahan dalam pembuatan lapisan BSF, ditetapkan bahwa nilai optimum harus memberikan peningkatan efisiensi marjinal terhadap peningkatan ketebalan lapisan lebih besar atau sama dengan 0,01%/mikron. Optimasi matematis dilakukan dengan metode brute force search. Berdasarkan hasil optimasi, direkomendasikan untuk meningkatkan ketebalan lapisan boron hingga 20 mikron dan meningkatkan konsentrasi sampai 3,40x1018/cm3. Apabila rekomendasi desain dapat dipenuhi, efisiensi sel surya dengan boron p+ dapat ditingkatkan hingga 17,58%

Application of [Ba. sub. 0.5][Sr. sub. 0.5] Ti [O. sub. 3](Bst) Film Doped with 0%, 2%, 4% and 6% Concentrations of Ru [O. sub. 2] as an Arduino Nano-Based Bad Breath Sensor

Ba0.5Sr0.5TiO3 (BST) film doped with variations in RuO2 concentration (0%, 2%, 4%, and 6%) has been successfully grown on a type-p silicon substrate (100) using the chemical solution deposition (CSD) method and spin-coating at a speed of 3000 rpm for 30 s. The film on the substrate was then heated at 850 °C for 15 h. The sensitivity of BST film + RuO2 variations as a gas sensor were characterized. The sensitivity characterization was assisted by various electronic circuitry with the purpose of producing a sensor that is very sensitive to gas. The responses from the BST film + RuO2 variation were varied, depending on the concentration of the RuO2 dope. BST film doped with 6% RuO2 had a very good response to halitosis gases; therefore, this film was applied as the Arduino-Nano-based bad-breath detecting sensor. Before it was integrated with the microcontroller, the voltage output of the BST film was amplified using an op-amp circuit to make the voltage output from the BST film readable to the microcontroller. The changes in the voltage response were then shown on the prototype display. If the voltage output was ≤12.9 mV, the display would read “bad breath”. If the voltage output >42.1 mV, the display would read “fragrant”. If 12.9 mV < voltage output ≤ 42.1 mV, the display would read “normal”

Developing Nuclear Security Capacity of Indonesia’s Police and Security Officer: Lessons from Universitas Gadjah Mada’s Pilot Training

Due to an increase in global nuclear security issues, there need to be improvements in human resources and security measures. The Republic of Indonesia is an archipelago country, which makes surveilling for nuclear security threats complicated. Recent radioactive material smuggling incidents proved that Indonesian police and security officers’ knowledge in nuclear security has been challenged and must be improved. In response, Universitas Gadjah Mada’s Nuclear Engineering Program composed a three-day pilot training program for local police and UGM\u27s security officers in 2018. The objective of the training was to improve their capabilities in dealing with nuclear security issues around where they work and serve. Training materials were designed to introduce nuclear technology and provide the basic skills of handling nuclear security matters. The training was divided into 12 sessions, based on the needs stated by the Special Region of Yogyakarta\u27s police chief. Lessons were delivered through traditional teaching, table-top exercises, exercises, and discussion. Fifteen-question pre-tests and post-tests were conducted to assess the officers’ knowledge of the training materials and the benefits of being trained. Based on the tests, we concluded that the participants’ understanding of nuclear security had improved. This increase in understanding was because the training materials fit their job needs, presented in various methods, and the participants’ awareness grew. It led to an increase in their awareness for securing the facilities utilizing radioactive sources in the Yogyakarta area. They said that the number of trainees in this event still does not meet the number of facilities that have to be secured. Therefore, the training should be carried out again and can be improved based on the participants\u27 feedback. Furthermore, this training could be expanded and applied to the whole country

Synthesis and Characterization of Tin Oxide-MultiWalled Carbon Nanotube Composite Material as Carbon Monoxide Gas Sensor

Gas sensor based on nanostructured tin oxide (SnO2) and multi-walled carbon nanotube (MWCNT) composite material has successfully been synthesized. Reflux method was used to produce SnO2-MWCNT powder with various ratio 1:0, 4:1, 2:1, 1:1 and 0:1. The XRD result shows that the synthesized material comprises of the combination of carbon elements (MWCNT) and SnO2 of the crystalite cassiterite phase. BET analysis shows that MWCNT particles increase the specific surface area of SnO2 particles. SEM images show the morphology of the SnO2 nanoparticle composite attached to the MWCNT wall with a diameter of 40-60 nm and dispersed around it. Gas sensor testing was carried out at room temperature, 50, 100, 150, 200, 250, 300, and 350°C. All sensor samples were exposed to 30 ppm CO gas for 15 minutes. . It was found that sample with 1:0 ratio gives the best response with 98.91% at 350°C. CO gas tests have also been carried out at various concentration 10, 30, 50 and 70 ppm to 4:1 SnO2-MWCNT sample at 150°C. The higher the CO gas concentration, the greater the response. SnO2-MWCNT with 4:1 ratio at 50°C has the fastest response time of 10 s and the fastest recovery time of 3 s

Studi Ketahanan [Cu3(C6H3(COO)3)2(H2O)3]n (HKUST-1) terhadap Radiasi Gamma pada Dosis 125 kGy hingga 200 kGy

Manajemen limbah radioaktif gas dan cair menjadi tantangan besar bagi perkembangan energi nuklir, terutama apabila zat tersebut berisiko mudah menyebar ke lingkungan. Hong-Kong University of Science and Technology-1 (HKUST-1) merupakan material berpori yang berpotensi menjadi adsorben radioaktif karena memiliki daya adsorpsi dan efisiensi adsorpsi yang tinggi. Namun, ketahanan radiasi dari material HKUST-1 juga perlu untuk dipertimbangkan ketika digunakan sebagai adsorben radioaktif. Oleh karenanya, penelitian ini dilakukan untuk menganalisis efek dari radiasi gamma terhadap karakteristik HKUST-1. Pada penelitian ini HKUST-1 diproduksi dengan metode solvotermal bersuhu 100°C. Penelitian ini mempelajari efek radiasi gamma pada HKUST-1 pada dosis 125, 150, 175, dan 200 kGy. Iradiasi dilakukan di Iradiator Gamma Merah Putih (IGMP), Serpong menggunakan sumber cobalt-60 dengan aktivitas 145 kCi. Material kemudian dikarakterisasi menggunakan uji SEM berspesifikasi Jeol JSM IT-200, uji XRD bersumber X-ray copper energi 40 kV, dan uji adsorpsi isotermal menggunakan adsorbat gas nitrogen. Berdasarkan hasil pengukuran, kenaikan dosis menghasilkan ukuran grain kristal cenderung turun. Kenaikan dosis menyebabkan bentuk kristal memiliki titik sudut cenderung tajam dan nilai kristalinitasnya meningkat dari 15,49% hingga 17,70%, kecuali pada dosis 175 kGy bentuk titik sudut kristal menjadi tumpul dan kristalinitasnya turun menjadi 16,21%. Pada hasil uji BET diperoleh kecenderungan kenaikan volume gas teradsorpsi dari 212,186 cm3/g hingga 340,335 cm3/g, kenaikan luas permukaan dari 520,379 m2/g hingga 917, 048 m2/g, dan kenaikan volume pori dari 0,424 cm3/g hingga 0,615 cm3/g,. Sebaliknya, radius pori menurun dari 1,631 nm menjadi 1,341 nm, kecuali pada dosis 175 kGy yang memiliki nilai 1,399 nm. Hasil tersebut meningkat dari 1,352 nm milik 150 kGy

Analysis of Back Surface Field (BSF) Performance in P-Type And N-Type Monocrystalline Silicon Wafer

Back Surface Field (BSF) has been used as one of means to enhance solar cell performance by reducing surface recombination velocity (SRV). One of methods to produce BSF is by introducing highly doped layer on rear surface of the wafer. Depending on the type of the dopant in wafer, the BSF layer could be either p+ or n+. This research aims to compare the performance of BSF layer both in p-type and n-type wafer in order to understand the effect of BSF on both wafer types. Monociystalline silicon wafer with thickness of 300 μm. area of 1 cm2, bulk doping level NB = 1.5×1016/cm3 both for p-type wafer and n-type wafer are used. Both wafer then converted into solar cell by adding emitter layer with concentration NE =7.5×1018/cm3 both for p-type wafer and n-type wafer. Doping profile that is used for emitter layer is following complementary error function (erfc) distribution profile. BSF concentration is varied from 1×1017/cm3 to 1×1020/cm3 for each of the cell. Solar cell performance is tested under standard condition, with AM1.5G spectrum at 1000 W/m2. Its output is measured based on its open circuit voltage (Voc). short circuit current density (JSC), efficiency (η). and fill factor (FF). The result shows that the value of VOC is relatively constant along the range of BSF concentration, which is 0.694 V – 0.702 V. The same pattern is also observed in FF value which is between 0.828 – 0.831. On the other hand, value of JSC and efficiency will drop against the increase of BSF concentration. Highest JSC which is 0.033 A/cm2 and highest efficiency which is 18.6% is achieved when BSF concentration is slightly higher than bulk doping level. The best efficiency can be produced when BSF concentration is around 1×1017cm-3.. This result confirms that surface recombination velocity has been reduced due to the increase in cell’s short circuit current density and its efficiency. In general both p-type and n-type wafer will produce higher efficiency when BSF is applied. However, the increase is larger in p-type wafer than in n-type wafer. Better performance for solar cell is achieved when BSF concentration is slightly higher that bulk doping level because at very high BSF concentration the cell’s efficiency will be decreased

ANALISIS PENGARUH KETEBALAN LAPISAN KROM TERHADAP LAJU KOROSI PADA SAMPEL LOGAM ASTM A480 STUDI KASUS DI PANTAI BURUNG MANDI DAN PARANG TRITIS

Corrosion is a chemical phenomenon that can cause damage on metal because of its interaction with environment. This study is aimed to the development of practical methods to minimize the corrosion process on metal ASTM A480 and to demonstrate the effect of coating thickness variations to the rate of corrosion. Corrosion process itself could be minimized by various methods, such as coating method

Nuclear Security Training: A New Approach for Educating Nuclear Technology in Indonesia

Indonesia has planned to erect Nuclear Power Plant for along time, but the government always postponed the plan due to the presence of anti-nuclear group that decreases the public acceptance. In addition, the public knowledge on nuclear technology is still low, since they only get in the last month before finish their study in high school. The socialization of nuclear technology done by government body could not significantly increase the public acceptance, since the knowledge and confidence on nuclear technology among the government employee is also low. The recent issue regarding to nuclear security give a new opportunity in socializing strategy. Department of Nuclear Engineering and Engineering Physics Universitas Gadjah Mada (UGM) as the only one university in Indonesia offering nuclear engineering education had conducted several nuclear security training for specific people who had been not targeted in previous socialization programs. The training done in collaboration with National Nuclear Energy Regulatory Body (BAPETEN) of Indonesia was conducted in Batam, Surabaya and Jakarta. Almost 20 people coming from police department, national coast guard, custom agency, etc attended in the training. Training materials consist of introduction on nuclear technology, introduction on nuclear security, physical protection system, radiation detection, transport security, etc. Pre-test and post-test were done to know their improvement. This was first time for most of participants to get nuclear technology knowledge. Based on the survey their knowledge was significantly improved. They felt that the training was valuable for them to know the benefit and risk of nuclear technology. We believe that it could increase the public participant and acceptance on utilizing nuclear technology in Indonesia