Judul: Model Sistem Monitoring Tangki CST Berbasis IoT dengan Mekanisme Pengolahan Citra dan Displacer
Abstrak: Pemantauan tebal lapisan minyak penting dilakukan karena mempengaruhi kadar kotoran di overflow. Saat ini pengukuran tebal lapisan minyak pada tangki CST masih dilakukan secara manual oleh operator menggunakan selang bening atau gelas penduga. Data pemantauan diukur setiap 2 jam sekali oleh operator di atas tangki yang panas. Data yang dihasilkan tidak kontinu, input data secara manual, serta mengharuskan operator hadir secara on-site. Pengukuran tebal lapisan fluida dapat digantikan dengan penggunaan kamera atau dengan sensor berat menggunakan load cell. Penelitian ini bertujuan merancang bangun model sistem monitoring ketebalan lapisan fluida pada tangki CST dengan berbasis IoT. Penelitian ini terdiri beberapa tahapan, antara lain : Identifikasi dan perumusan masalah, perancangan fungsional sistem monitoring, perancangan struktural hardware, pengujian dan kalibrasi hardware perancangan arsitektur software, dan pengujian kinerja sistem monitoring. Hasil pengukuran membuktikan variasi metode pengolahan citra tanpa objek referensi memiliki kinerja terbaik diukur dari akurasi 95,7%, durasi olah data 0,04 detik, durasi transfer data 2,5 detik, dan komponen yang lebih sedikit, namun metode ini sensitif terhadap perubahan posisi kamera. Penambahan objek referensi mampu mengkompensasi perubahan posisi kamera, namun pendeteksian objek referensi yang tidak tepat menyebabkan rendahnya akurasi yaitu sebesar 88,91% dan peningkatan durasi olah menjadi 0,09 detik. Metode displacer dapat diterapkan, apabila tidak memungkinkan pengolahan citra dilakukan. Metode displacer tunggal berkinerja cukup baik dengan akurasi hingga 90,05% dengan diameter 50 mm, namun metode displacer tunggal sensitif terhadap perubahan suhu sehingga membutuhkan pengkoreksi dari persamaan densitas atau dari displacer kalibrasi. Penggunaan displacer kalibrasi dan persamaan densitas terbukti mampu mengkompensasi perubahan suhu fluida. Data pengukuran tersebut disimpan pada server Google Spreadsheet, kemudian ditampilkan pada aplikasi monitoring yang telah dibuat., Monitoring the thickness of the oil layer is important because it affects the level of dirt in the overflow. Currently, the measurement of the thickness of the oil layer in the CST tank is still carried out manually by the operator using a clear hose or measuring cup. Monitoring data is measured every 2 hours by the operator on a hot tank. The data generated is not continuous, input data manually, and requires the operator to be present on-site. The thickness measurement of the fluid layer can be replaced by the use of a camera or by a weight sensor using a load cell. This study aims to design a model of a fluid layer thickness monitoring system in a CST tank based on IoT. This research consists of several stages, including: Identification and formulation of problems, functional design of monitoring systems, structural hardware design, hardware testing and calibration of software architecture design, and monitoring system performance testing. The measurement results prove that variations in image processing methods without reference objects have the best performance measured from 95.7% accuracy, data processing duration 0.04 seconds, data transfer duration 2.5 seconds, and fewer components, but this method is sensitive to changes in position. camera. The addition of a reference object is able to compensate for changes in camera position, but the detection of an inappropriate reference object causes a low accuracy of 88.91% and an increase in processing duration to 0.09 seconds. The displacer method can be applied, if it
Keyword: CST, Calibration displacer, Google Spreadsheet, Monitoring oil, Reference object image processing

Judul: Studi Awal Perancangan Alat Pengukur Viskositas Terkomputerisasi Menggunakan Metode Bola Jatuh Hukum Stokes
Abstrak: Metode bola jatuh hukum Stokes merupakan salah satu metode yang digunakan dalam pengukuran viskositas fluida. Metode bola jatuh hukum Stokes digunakan pada praktikum penentuan koefisien viskositas fluida Mata Kuliah Fisika Sains dan Teknologi PKU IPB. Parameter krusial metode bola jatuh hukum Stokes adalah waktu, sedangkan pengukuran waktu pada praktikum penentuan koefisien viskositas fluida masih dilakukan secara manual menggunakan stopwatch yang menyebabkan kurang akuratnya nilai waktu yang dihasilkan. Sehingga perlu dilakukan studi awal perancangan alat pengukur viskositas menggunakan sensor LDR dan LED. Hasil yang didapatkan menunjukkan nilai viskositas tidak berbeda secara signifikan, nilai viskositas fluida yang dihasilkan dalam percobaan sebagai berikut: air objek 1 (0,36 ± 0.02), air objek 2 (0,083 ± 0.007), air objek 3 (0,06 ± 0.02), air objek 4 (0,023 ± 0.001), oli objek 1 (0,82 ± 0.02), oli objek 2 (1,3 ± 0.3), oli objek 3 (1,32 ± 0.04), oli objek 4 (1,27 ± 0.02), minyak objek 1 (0,5 ± 0.03), minyak objek 2 (0,66 ± 0.04), minyak objek 3 (0,52 ± 0.01), minyak objek 4 (0,4 ± 0.03), gliserin objek 1 (0,81 ± 0.02), gliserin objek 2 (1,5 ± 0.1), gliserin objek 3 (1,4 ± 0.2), gliserin objek 4 (1,5 ± 0.2), sehingga Alat pengukur viskositas menggunakan sensor LDR dan LED dengan metode bola jatuh hukum Stokes direkomendasikan sebagai alat bantu praktikum penentuan koefisien viskositas fluida Mata Kuliah Fisika Sains dan Teknologi PKU IPB., The Stokes law of ball fall method is one of the methods used in the measurement of fluid viscosity. Stokes's law of ball fall method has been done on the practice of determining the fluid viscosity coefficient of the University of Physics Science and Technology PKU IPB. The crucial parameter of the Stokes law ball fall method is time, while the measurement of time on the practice of determining the fluid viscosity coefficient is still done manually using a stopwatch which causes less accuracy of the time value generated. Therefore, a preliminary study of the design of viscosity measuring devices using LDR and LED sensors should be carried out. The obtained results showed that the viscosity values did not differ significantly, the values of fluid viscosity produced in the experiment as follows: water 1 object (0,36±0.02), water 2 object (0,083±0.007), water 3 object (0,06±0,02), water 4 subject (0,0023±0,001), object 1 fried oil (0,82±0.02), object 2 fried oil (1,3±0.3), object 3 fried oil (1,32±0.04), object 4 fried oil (1,27±0.01), object 1 oil (0,5±01.03), object 2 oil (0,66±0,04), object 3 oil (0,52±0,01), subject 4 oil (0,54±0.093), object 1 glycerin (0,81±02.02), object 2 glycerin (1,5±0.1), object 3 glycerin (1,4±0,2), object 4 glycerin (1,5 ±0.2), thus the viscosity measuring device using LDR and LED sensors with the ball falling method Stokes law recommended as a practical aid tool for determining fluid viscosity coefficient Eye School of Physics and Technology PKU IPB.
Keyword: LDR Sensor, Stokes Law, Terminal Speed, Viscosity

Judul: Lejeuneaceae Subfamily Ptychanthoideae (Hepaticae) in  West Java
Abstrak: Subfamily Ptychanthoideae of the family Lejeuneaceae (Hepaticae) in West Java is still poorly known. Publications on this subfamily are out of dated and written in the 19th or early of 20th century. The last taxonomic treatment of Ptychanthoideae of West Java was in 1933, many species names have changed since then. Studies on Ptychanthoideae of West Java are urgently needed. Studies on the Ptychanthoideae were based on the specimens collected from West Java. A total number of 361 of specimens deposited in the Herbarium Bogoriense (BO), Herbarium Biotrop (BIOT), Gottingen Herbarium (GOET) and Bangi Herbarium (UKMB) were examined, those are old and several recent specimens collected in West Java. Recent collections were made from Telaga Warna, Ciater, Gunung Halimun Salak National Park, Cibodas Botanical Garden, Bodogol Education Center and Conservation (Gunung Gede Pangrango National Park), University of Indonesia Campus Depok, including several collections from Banten Province. Twenty four species of Lejeuneaceae subfamily Ptychanthoideae are known from West Java, belonging to 8 genera namely Acrolejeunea (Spruce) Schiffn. (2 species), Archilejeunea (Spruce) Schiffn. (1 species), Lopholejeunea (Spruce) Schiffn. (10 species), Mastigolejeunea (Spruce) Schiffn. (3 species), Ptychanthus Nees (1 species), Schiffneriolejeunea Verd. (1 species), Spruceanthus Verd. (2 species) and Thysananthus Lindenb. (4 species). Two new records of Ptychanthoideae: Mastigolejeunea indica Steph. and Thysananthus minor Verdoorn are reported for Java. A determination key to the species is presented including their descriptions and illustrations.
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