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"[ABSTRAKTeknologi gelembung pada saat ini digunakan diberbagai industri dan berbagai aspek. Teknologi gelembung yang digunakan pada penelitian kali ini adalah proses flotation. Proses flotasi ini prinsipnya adalah pemisahan material dengan menggunakan gelembung. Pemisahan yang dilakukan adalah dengan memisahkan material berharga dan tidak berharga. Material berharga tersebut dapat dipisahkan dari material pengotor seperti tanah, pasir, dan debu karena adanya sifat material yaitu hydrophobic dan hydrophilic. Dalam penelitian kali ini, parameter proses flotasi yang diteliti adalah kinematika dari partikel yang berinteraksi dengan gelembung. Kinematika partikel ini dipelajari untuk mendapatkan hasil pengaruh geometri dan ukuran pada partikel di proses flotasi. Partikel yang digunakan adalah partikel berukuran 300, 212, 150 dan 106 mikron. Pengambilan data dilakukan dengan menggunakan High Speed Video Camera. Data hasil pengamatan ini didapatkan hasil partikel yang digunakan dominan berbentuk bladed – sub angular. Jarak Rc paling efektif didapatkan pada jarak Rc = 0 atau tepat ditengah gelembung dan jarak Rc = 1/2 r gelembung serta probabilitas tumbukan dan pelekatan partikel berdasarkan Rc. Kecepatan terminal juga didapatkan tren 300 mikron > 212 mikron > 150 mikron > 106 mikron. Terakhir adalah interaksi antara partikel dengan gelembung yang memiliki lima zona berdasarkan perpindahannya terhadap waktu. Hasil pengamatan dan analisis ini diharapkan dapat mendukung pengembangan proses flotasi kedepannya.

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ABSTRACTBubble technology is currently being used in various industries and various aspects. Bubble technology used in this research is the process of flotation. The flotation process is the principle of separation of materials by using a bubble. Separation is done by separating the valuable material and worthless. The valuable material can be separated from material impurities such as soil, sand, and dust because of the nature of the material that is hydrophobic and hydrophilic. In the present study, the flotation process parameters studied were the kinematics of particles that interact with the bubbles. Particle kinematics is studied to get the effect of the geometry and size of the particles in the flotation process. Particles diameter are 300, 212, 150 and 106 microns. Data collection was performed by using a High Speed Video Camera. Data from these observations showed that the particles are used predominantly shaped bladed - sub angular. Rc most effective distance obtained at the distance Rc = 0 or right in the middle of bubbles and distance Rc = 1/2 r bubble as well as the probability of collision and adhesion of particles based Rc. Terminal velocity also found a trend of 300 microns> 212 microns> 150 microns> 106 microns. The latter is the interaction between particles with the bubble which has five zones based on the displacement of the time. The observation and analysis is expected to support the future development of the flotation process., Bubble technology is currently being used in various industries and various aspects. Bubble technology used in this research is the process of flotation. The flotation process is the principle of separation of materials by using a bubble. Separation is done by separating the valuable material and worthless. The valuable material can be separated from material impurities such as soil, sand, and dust because of the nature of the material that is hydrophobic and hydrophilic. In the present study, the flotation process parameters studied were the kinematics of particles that interact with the bubbles. Particle kinematics is studied to get the effect of the geometry and size of the particles in the flotation process. Particles diameter are 300, 212, 150 and 106 microns. Data collection was performed by using a High Speed Video Camera. Data from these observations showed that the particles are used predominantly shaped bladed - sub angular. Rc most effective distance obtained at the distance Rc = 0 or right in the middle of bubbles and distance Rc = 1/2 r bubble as well as the probability of collision and adhesion of particles based Rc. Terminal velocity also found a trend of 300 microns> 212 microns> 150 microns> 106 microns. The latter is the interaction between particles with the bubble which has five zones based on the displacement of the time. The observation and analysis is expected to support the future development of the flotation process]"

"Gelembung merupakan suatu wujud dari fluida dua fase yang memiliki fenomena yang menarik untuk diketahui dan diteliti.Keunikan dari dinamika dari gelembung ini dapat memberikan dampak yang baik untuk berbagai industry, salah satunya industry pertambangan. Proses flotasi yang memanfaatkan gelembung sebagai pemisah material berharga dan tidak berharga digunakan dalam industry material. Untuk mendapatkan efisiensi serta proses flotasi yang baik, studi mengenai eksperimen dinamika gelembung dilaksanakan. Dinamika gelembung tidak hanya berbicara tentang pergerakan gelembung, tetapi juga mengenai bagaimana gelembung terbentuk. Proses gelembung terbentuk atau bubble generation merupakan proses evolusi diameter gelembung dari gelembung belum terbentuk hingga gelembung terlepas dari suatu bubble generator yang terbentuk dari pompa udara. Dalam studi ini, gelembung yang diteliti bersifat kecil atau small-bubble yang keluar dari satu nozzle atau single nozzle. Gelembung yang diteliti akan memperlihatkan fenomena bagaimana dinamika diameter yang terbentuk, gaya-gaya yang bekerja pada gelembung selama pembentukannya, karakteristik bentuk gelembung selama proses evolusi, dan perubahan sudut kontak antara gelembung dengan nozzle. Tidak hanya itu, variasi flow-rate yang masuk serta media larutan untuk gelembung mengalir juga menjadi eksperimen untuk mengetahui perubahan karakteristik gelembung tersebut. Sifat-sifat tersebut kemudian dikaitkan bahkan dipelajari sehingga proses flotasi.

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Bubble is fluid form from two phases which has remarkable phenomenon for experiment process. The unique bubble dynamic has good effect for industries, namely mineral industry. Flotation process using bubble as separating mineral valuable and non-valuable is used in material industry. For achieving decent process and efficient of flotation, study for bubble dynamic must be taken place. Bubble dynamic is not only its trajectory and movement, but also about its generation. Bubble generation process is bubble diameter evolution from its initial shape which is none into big diameter until bubble is attached from its bubble generator from air pump. In this case, bubble is researched in small size or small bubble out from single nozzle. Bubble will show its phenomenon about process of diameter evolution, forces actiong on bubble on its generation, characteristic of its shape, and contact angle between bubble and nozzle. Variation of air flow-rate and fluid media for bubble streaming becomes additional study to know more about bubble characteristic. In addition, those characterics and results will be learned more to know its effect for flotation optimation."

"ABSTRAKProses flotasi adalah salah satu proses separasi yang digunakan secara luas saat ini, salah satunya pada industri tambang. Mineral tambang yang masih bercampur zat pengotor dimasukkan ke dalam kolom flotasi yang telah dicampur larutan kimia yang membuat mineral berharga menjadi hidrofobik dan zat pengotornya hidrofilik. Lalu mineral tambang yang hidrofobik akan menempel pada gelembung dan terangkat ke permukaan air sedangkan zat pengotornya akan mengendap di dasar kolom flotasi. Penelitian kinematika partikel kali ini akan menggunakan partikel yang diambil dari tambang yang sesungguhnya yaitu partikel tembaga dengan ukuran 38μm, 45μm, 53μm dan 75μm. Kinematika partikel yang dimaksud meliputi kecepatan terminal, bentuk partikel, dan lintasan partikel. Pengambilan data dilakukan dengan highspeedcamera dengan kecepatan 500fps. Dari penelitian didapatkan bahwa bentuk partikel yang paling dominan adalah oblate- subangular. Jarak Rc dengan probabilitas tumbukan dan pelekatan paling tinggi adalah Rc= 0. Partikel 38 μm memiliki probabilitas tumbukan paling rendah sedangkan partikel 75 μm adalah yang paling tinggi. Namun, Partikel 38 μm memiliki probabilitas pelekatan paling tinggi sedangkan probabilitas pelekatan 75 μm paling rendah. Untuk kecepatan terminal, tren menunjukkan bahwa kecepatan terminal meningkat seiring bertambahnya ukuran partikel.Diharapkan hasil eksperimen dan analisis ini dapat membantu perkembangan penelitian teknologi gelembung ke depannya.

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ABSTRACTFlotation Process is one of separation process which is widely used nowdays, mining industry is one of the examples. Mining minerals which is mixed with pollutant are fed to the flotation cell after some chemical process which caused the mixing turn into hydrophobic and hydrophylic. The mining mineral which turns into hydrophobic attach to the bubble and float to the surface while the pollutant which is hydrophobic drown to the cell bottom. This experiment use actual mining minerals, copper with 38μm, 45μm, 53μm and 75μm in size. Particle dynamics here mean to particle?s terminal velocity. Geometry, and it?s trajectory. Experiment?s data is obtained by highspeedcamera in 500fps. The experiment results show that oblate-subangular is the dominant geometry of the particles. Rc=0 distance is the most efficient distance. 38 μm has the highest attachment probability but the least collision probability while 75 μm has the opposite. For terminal velocity, trend shows that it will raise along with the particle?s size increase. We hope that these experiment results and the analyze can provide an information for the improvement of bubble technology."

"Kurangnya stabilitas oksidasi biodiesel menyebabkan banyak kendala dalam pemanfaatannya. Untuk mengatasi hal ini, stabilitas oksidasi biodiesel perlu ditingkatkan melalui proses hidrogenasi parsial yang dapat dilakukan dalam reaktor multifasa. Reaktor Slurry Bubble Column, salah satu jenis reaktor multifasa, yang telah banyak digunakan dalam proses hydrotreating, berpotensi untuk menyelenggarakan proses ini dalam sistem kontinyu. Akan tetapi, belum ada penelitian yang mempelajari penggunaan reaktor Slurry Bubble Column untuk mengubah biodiesel menjadi H-FAME melalui proses hidrogenasi parsial. Oleh karena itu, tujuan penelitian adalah untuk mengembangkan model matematis reaktor Slurry Bubble Column 2 dimensi axis-symmetric untuk proses hidrogenasi parsial. Model yang akan dibangun didasarkan pada persamaan kontinuitas untuk transport massa dan transport energi dengan modifikasi koefisien dispersi, juga penurunan tekanan dan distribusi katalis di sepanjang sumbu reaktor dan disimulasikan pada COMSOL MultiPhysic 5.4. Dalam penelitian ini, digunakan model kasus dasar reaktor kolom berbentuk silinder vertikal dua dimensi. Reaktor ini beroperasi pada 500 kPa, suhu saluran masuk 150 ° C. Umpan terdiri dari metil linoleat murni yang mewakili biodiesel dan hidrogen murni. Kecepatan gas masuk adalah 0,02 m/s, dan kecepatan cairan masuk adalah 0,00025 m/s. Hasil simulasi menunjukkan bahwa konversi metil-linoleat adalah 76,98%, hasil H-FAME adalah 54,8% berat, dengan kemurnian 54,45% berat.

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Biodiesel`s lacks of oxidation stability presents many constraints in its utilization. To enhance this property, biodiesel needs to be upgraded through partial hydrogenation process which can be carried out in a multiphase reactor. Slurry bubble column, a type of multiphase reactor, which has been widely used in hydro-treating process, has potential to perform this process in a continuous system. However, no previous studies had shown the usage of slurry bubble column for upgrading biodiesel to H-FAME via partial hydrogenation process. Therefore, this study purpose was to develop a two-dimensional axis-symmetric reactor model for this process. The model was based on equation of continuity on mass transport and energy transport with dispersion coefficient, also pressure drop and catalyst distribution along the reactor axis and simulated on COMSOL MultiPhysic 5.4. In this study, a base case model, two-dimensional, axis-symmetry, vertical cylinder-shape slurry bubble column reactor was used. This reactor operated in 500 kPa, inlet temperature of 150 °C. The feed consisted of pure methyl-linoleate as biodiesel representation and pure hydrogen. The inlet gas velocity was 0.02 m/s, and the inlet liquid velocity was 0.00025 m/s. Simulation results show that the conversion of methyl-linoleate was 76,98%, H-FAME yield was 54.8% wt, with 54.45% wt purity. Keywords: Biodiesel, Partial Hydrogenation, H-FAME, Slurry Bubble Column Reactor, dispersion model, COMSOL, multiphase, Methyl Linoleate."

"Pada proses flotasi terdapat 3 sub-proses penting, yaitu penipisan interverensi dari lapisan fluida menjadi ketebalan kritis, pecahnya lapisan liquid terinterverensi dan pembentukan formasi kontak tiga fasa, serta ekspansi garis kontak tiga fasa mencapai kestabilan agregat. Kestabilan agregat menentukan keberhasilan proses separasi. Kestabilan agregat ditentukan oleh beberapa faktor yaitu reagent, geometri dan ukuran partikel. Penelitian ini bertujuan untuk memahami pengaruh geometri dan ukuran partikel terhadap stabilitas agregat. Eksperimental setup terdiri dari kolom flotasi dengan ukuran 9x9x26 cm dilengkapi dengan bubble generator, particle feeding system, dan video kamera berkecepatan tinggi (high speed video camera). Bubble generator berupa single nozzle berdiamater 0,3 mm yang dihubungkan ke programmable syringe pump. Particle feeding system terbuat dari pipet. Partikel yang digunakan dalam penelitian ini adalah partikel hasil tambang tembaga dengan bentuk sub-angular dengan ukuran antara 38-300 μm. Hasil rekaman high speed video camera diolah dan dianalisa dengan menggunakan image processing software. Hasil penelitian diharapkan akan menambah pemahaman pengaruh geometri dan ukuran partikel pada interaksi bubble-particle khususnya stabilitas agregat. Hasil eksperimen menunjukkan stabilitas agrgegat bubble-partikel dan waktu induksi (waktu partikel melekat pada bubble) dipengaruhi oleh ukuran partikel. Semakin kecil ukuran partikel, semakin besar probabilitas terbentuk agregat yang stabil dan semakin panjang waktu induki. Partikel berukuran 38 𝜇m, 45 μm, 75 μm, 106 μm mamapu membentuk agregat stabil sehingga melekat pada gelembung. Sedangkan, partikel berukuran 150 μm dan 300 μm tidak mampu membentuk agregat stabil sehingga tidak melekat pada gelembung.

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There are three sub-proces on flotation. These processes are intervening liquid film intu critical thickness, rupture of liquid film forming three phase contact line, and expansion three phase contact line forming agregate stability. Agregate stability determines flotation efficiency. Agregate stability has some important factors such as reagent and particle geometry.

This research focus on understanding effect of particle geometry to agregate stability. Experimental setup consists of 9x9x26 cm flotation coloumn made of glass, bubble generator, particle feeding system, and high speed video camera. Bubble generator made from single nozzle with 0,3 mm diameter attached to programmable syringe pump. Particle feeding system made of pipette. Particle used in this research is taken from open pit Grasberg in timika, Papua. Parcile has sub-angular size and varies between 38-300 μm. Recordings from high speed video camera analyzed using image processing software.

Experiment result shows thet agregate particle-bubble and induction time depends on particle size. The smaller particle size, the higher probability attachment, agregate stability, and iduction time. Particle with size 38 𝜇m, 45 μm, 75 μm, 106 μm able to form stable agregate. While, particle with size 150 μm and 300 μm unable to form stable agregate."

"The combination ofbaffled air flotation and a membrane system for the treatment of palm oil milleffluent (POME) was studied. The POME was obtained from a palm oil factory inPTPN I Tanjong Seumantoh, Aceh, Indonesia. Operation variables and conditions,such as the hydraulic retention time and air flow rates, were varied to findthe optimum process. The air flotation process is able to reduce theconcentration of suspended solids and fats/ oils contained in the wastewater,which increases the performance of the membrane by reducing clogging. Theresults showed that this method was promising for POME treatment. The optimumorganic removal efficiency of the air flotation pretreatment was obtained atHRT = 5 days and at an air flow rate of 11 L/min. The effluent was subsequentlypassed through an anaerobic membrane system to achieve the highest removalefficiency treatment. The removal efficiency of chemical oxygen demand (COD),total suspended solids (TSS), turbidity, mixed liquor suspended solids (MLSS),mixed liquor volatile suspended solids (MLVSS), and fats/oils after passingthrough the membrane system were 97%, 93.9%, 99.8%, 94.5%, 96.2%, and 99.9%,respectively. The results also showed that the pH could be neutralized to 6.18,while a dissolved oxygen (DO) level of 1.60 mg/L could be achieved. A highquality of effluent was obtained, which met the standards for POME effluent."

"Batik waste can increase water characteristics, such as turbidity, colorand total suspended solids (TSS). Thus, an efficient technique for separatingBatik from the liquid to decrease these characteristics is needed. The aim ofthe current study was to understand the results of flotation using electrolysisand to investigate the bubble characteristics that influence the results of theflotation of Batik waste. Flotation studies have been conducted usingelectrolysis to produce bubbles to separate batik synthetic dye from theliquid. Research conducted with 316L stainless steel electrodes, inside a 100cm tall acrylic pipe with an inner diameter of 8.4 cm and a voltage variationof 10, 15 and 20 V. Batik waste was mixed with distilled water. Commercial alumpowder [aluminum sulfate, Al2(SO4)3.14H2O,that is 17% Al2O3] as the reagent was added to coagulateBatik waste in a ratio of 1 gram per 10 ml of Batik waste. The results showedthat flotation of Batik waste can be used to separate Batik waste with theaddition of alum. Alum was shown to be capable of acting as a collector in thistype of waste separation. The results showed that flotation using electrolysiscould be an effective method for reducing turbidity, color and TSS."

"Penelitian karakateristik microbubble generator jenis venturi tube dan spherical ball in flowing water telah dilakukan. Penelitian ini bertujuan untuk mempelajari pengaruh parameter geometri dan aliran terhadap karakter bubble yang dihasilkan. Penelitian ini menggunakan water loop system yang terdiri dari kolam pengamatan, pompa, flow meter, valve, dan test section. Test section adalah micro bubble generator jenis venturi dan spherical ball. Pada penelitian ini digunakan beberapa venturi microbubble generator dengan berbagai variasi bentuk geometri dan ukuran dilakukan pada berbagai variasi debit air dan debit udara. Hasil dari penelitian ini menunjukkan bahwa microbubble generator yang dirancang mampu menghasilkan microbubble. Parameter-parameter yang diujikan secara signifikan memberi pengaruh terhadap jumlah dan ukuran microbubble. Semakin besar debit udara, semakin banyak jumlah bubble yang dihasilkan namun ukuran bubble semakin besar. Debit air yang meningkat menghasilkan jumlah bubble yang semakin banyak dengan ukuran yang lebih kecil. Pengaruh perbadingan diameter bola dengan diameter tube pada spherical ball microbubble generator adalah signifikan. Semakin besar rasio diameter bola dengan diameter tube semakin kecil bubble yang dihasilkan. Dari penelitian ini dapat disimpulkan bahwa microbubble generator yang diuji mampu menghasilkan microbubble. Populasi dan ukuran microbubble sensitif terhadap rasio aliran udara dan air serta geometri dari microbubble generator.

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Research about characteristic of Venturi tube microbubble generator type and spherical ball in flowing water type has been carried out. This research aims to study the influence of geometry and flow parameters on bubble generated characters. This research use loop water system consist of the observation reservoir, pump, flow meters, valves, and test section. Test section is a micro-bubble generator venturi type and spherical ball type.

In this study, microbubble generator varies of air flow rate, water flow rate and geometry. Results from this study is the designed microbubble generator can produce microbubble. The tested parameters significantly influence the number and size of the microbubble. Increasing air flow rate will affect increasing number of bubbles produced with bigger bubble size. Water flow rate increased wil affect increasing produce number of bubbles with a smaller size. Effect of a comparison between the diameter of the ball diameter tube at the spherical ball microbubble generator are significant. The greater ratio of the ball diameter with tube, smaller diameter bubble will produced.

From this study it is concluded that microbubble generator capable microbubble. Microbubble size and population sensitive to air and water flow ratio and geometry of microbuble generator."

"Flotasi merupakan suatu pemisahan zat atau unsur kimiawi pada partikel di dalam cairan/larutan memanfaatkan gelembung sebagai teknologi terbaharukan. Partikel yang bersifat hidrofilik karena pengaruh reagent akan berinteraksi pada gelembung udara dan akan terbawa ke permukaan larutan. Tidak hanya itu, agregat ini kemudian bergerak dengan vektor yang fluktuatif karena sifat gelembung yang bergolak dengan kacau. Pengaruh gelembung yang bergerak atau dinamis dari nozzle akan menghasilkan perubahan profil aliran di kisaran gelembung, sehingga agregat yang terletak, khususnya di bagian atas dan bawah gelembung akan terganggu oleh vortex di sekitar gelembung. Namun arah aliran dari fluida yang terbentuk dari vortex pada partikel dapat mengacaukan proses pelekatan partikel pada gelembung Dalam proses simulasi, nilai kecepatan aliran di bagian atas partikel berkisar antara 51.5 ? 54.2 mm/s dimana valid dengan kecepatan gelembung yang berkisar 35 ? 37 mm/s. Tidak hanya itu, arah vektor fluida yang ditunjukkan pada hasil simulasi menggunakan Computational Fluid Dynamic menunjukkan besarnya perilaku untuk partikel menggelinding (rolling), meluncur (sliding) atau bertumbuk (bouncing) ke arah samping baik kiri maupun kanan. Selain itu, bentuk partikel juga dapat merubah profil medan aliran kisaran gelembung sehingga pergerakan gelembung akan membentuk profil yang diakibatkan adanya partikel yang melekat pada gelembung.

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Flotation is a separation of a substance or chemical elements in the particles in fluid / solution utilizing the bubble as renewable technologies. Particles hydrophilic due to the influence of reagent will interact on air bubbles and will carried to the surface of the solution. Not only that, the aggregate is then moved by the vector fluctuating due to the volatile nature of the chaotic bubbles. The influence of bubbles moving or dynamic of the nozzle will produce a change in the flow profile in the range of bubbles, so that the aggregate located, especially at the top and bottom of the bubble will be disturbed by the vortex around the bubble. But the direction of flow of the fluid formed of the vortex in the particle can disrupt the process of attachment of particles on the bubble in the simulation process, the value of the flow velocity at the top of the particles ranging between 51.5 - 54.2 mm / s where the bubbles are valid at speeds ranging from 35-37 mm / s. Not only that, the direction vector fluid shown in the simulation results using Computational Fluid Dynamic shows the behavior of the particles rolling (rolling), sliding (sliding) or fight (bounces) in the direction of either left or right side. In addition, particle shape as well can alter the flow field profile so that the range of movement of the bubbles will bubble forming a profile that caused the particles are attached to the bubble."

"ABSTRAKThe field of electrical engineering is inseparable from mathematics. One of the commonly used equations is differential equations, in both linear and nonlinear form. Solution of linear equations of differential equations can be obtained analytically, but the solution of nonlinear differential equations can not be easily obtained.The solution of the differential equation is necessary solved to understand the behavior of the dynamic system, therefore in the proses of simulation, a special method is required which can provide these numerical differential equations solution. This can be done with Matlab-Simulink programming.Matlab-Simulink software with version R2016a provides LIBRARY BROWSER facility which is very adequate and applied in windows system, and has LIBRARY which consist of many blocks; CONTINUOUS blocks, DISCONTINUITIES blocks, MATH OPERATIONS blocks, FUNCTION, SOURCES blocks, SINKS blocks and so on. Therefore the solution of a system that has a linear or nonlinear differential equation is very necessary to be disclosed."