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Abstrak :
ABSTRAK
Penelitian karakteristik sudut aliran udara pada performa generator microbubble dengan tabung silinder telah dilakukan. Penelitian ini bertujuan untuk mempelajari pengaruh parameter sudut aliran udara terhadap bubble yang dihasilkan. Penelitian ini menggunakan water loop system yang terdiri dari kolam pengamatan, kotak pengamatan, pompa, flowmeter, valve dan test section. Test section adalah generator microbubble jenis tabung silinder dengan bola. Pada penelitian ini digunakan 3 jenis generator microbubble dengan variasi sudut aliran udara yang dilakukan pada berbagai variasi debit air, debit udara dan ketinggian air. Parameter yang diujikan secara signifikan memberi pengaruh terhadap jumlah dan ukuran bubble. Semakin besar debit udara maka ukuran bubble yang dihasilkan semakin besar, sedangkan jika debit air meningkat maka semakin banyak microbubble yang dihasilkan. Pengaruh sudut aliran udara pada generator microbubble signifikan. Generator microbubble dengan sudut aliran 45? menghasilkan bubble dengan ukuran lebih besar dibandingkan dengan generator microbubble direct. Generator microbubble dengan sudut aliran 90? tidak dapat menghisap udara lebih 0.1 lpm sehingga tidak efisien dalam menghasilkan bubble. Penelitian ini dapat simpulkan bahwa generator microbubble mampu menghasilkan microbubble. Populasi serta ukuran microbubble sensitif terhadap sudut aliran udara. Microbubble generator dengan sudut udara langsung menghasilkan microbubble yang lebih banyak.

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ABSTRACT
Research about characteristic of microbubble generator sphericall ball has been carried out. This research aims to study the influence of airflow angle on bubble generated characters. This research use loop water system consist of observation reservoir, box reservoir, pump, flow meters, valves, and test section. Test section is a microbubble generator spherical ball. In this study, there are 3 types of microbubble generator with varies air flow angel that conducted in different varies water flowrate, air flowrate and height of water. The tested parameter significantly influence population and size of bubble. Increasing air flowrate will affect increasing size of bubble, while increasing water flowrate will increase microbubble. Effect of airflow angle in microbubble generator are significant. Microbubble generator with 45 airflow angle produce bigger size of bubble compare to direct microbubble generator. Microbubble generator with 90 air flow angle can rsquo t suction the air more than 0.1 lpm so inefficient to produce bubble. From this study it is concluded that microbubble generator capable produce microbubble. Population and size of bubble affected by airflow angle. Microbubble generator with airflow angle direct produce more microbubble than 45 and 90 airflow angle.

Abstrak :
Pada penelitian ini, penggunaan generator gelembung mikro untuk mengolah air baku Sungai Cikeas diteliti lebih lanjut secara proses flotasi dan aerasi. Penelitian dilakukan untuk mengetahui waktu kontak optimum pengolahan, hubungan antara konsentrasi DO dengan kontaminan lainnya, serta perbandingan efisiensi penyisihan kontaminan dengan pemberian koagulan PAC. Penggunaan generator gelembung mikro menggunakan metode aerasi dan flotasi untuk menyisihkan kontaminan kekeruhan, besi, mangan, TSS, BOD dan COD.  Dilakukan percobaan dengan koagulan dan tanpa koagulan untuk air sampel yang sama. untuk melihat pengaruh pemberian koagulan pada efisiensi penyisihan. Ditemukan bahwa waktu kontak optimum untuk penurunan konsentrasi kekeruhan, TSS, besi dan mangan  rentang 20 - 30 menit, 20 - 30 menit, 10 - 30 menit dan 30 - 60 menit. Peningkatan persentase penyisihan antara pemberian koagulan dan tanpa koagulan. Waktu kontak optimum dari peningkatan oksigen terlarut (DO) adalah 10 menit. Waktu kontak optimum dari pengoperasian generator gelembung mikro secara keseluruhan adalah 10 menit sebagai pengolahan Dissolved Air Flotation (DAF). Hubungan Konsentrasi DO dengan penurunan konsentrasi parameter dianalisis dimana konsentrasi berbanding terbalik. Serta peningkatan persentase penyisihan untuk kekeruhan, besi, mangan dan TSS adalah 27%, 79.65%, 0% dan 3% dengan pemberian koagulan. Penggunaan generator gelembung mikro sendiri lebih baik performa flotasi dan aerasinya apabila dilakukan pemberian koagulan pada dosis optimum. ......In this study, the application of microbuble generator to treat cikeas river raw water is furthered researched. The study is conducted to know the optimum retention time of treatment, the correlation between dissolved oxygen concentration with other contaminant, and the comparison of the contaminant removal efficiency for treatment with or without the addition of optimum dose coagulant PAC. The application of microbubble generator uses methods such as aeration and flotation to reduce turbidity, iron, manganese, TSS, BOD and COD contaminant. A same sample of cikeas river raw water is treated both ways, with coagulant and without coagulant to see the effect on the removal efficiency. It is found that the optimum retention time for decreasing turbidity, iron and manganese, Total suspended solid, is in the range 20-30 minutes, 20 -30 minutes, 10-30 minutes and 30-60 minutes.  Whereas, the optimum retention time  for dissolved oxygen is 10 minutes. In conclusion, the system as a whole has an optimum contact time of 10 minutes as a Dissolved Air Flotation (DAF) type unit. The increase in removal efficiency as a result of using coagulant in the treatment process for turbidity, iron, manganese, and total suspended solid are 27%,  79.65%, 0% and 3%. The performance of aeration and flotation process in the application of microbubble generator is better with the use of coagulant at the optimum dose.

Abstrak :
Hambatan merupakan salah satu faktor yang sangat penting dalam bidang teknologi transportasi laut. Salah satu metode yang dapat mengurangi hambatan pada kapal adalah dengan metode Microbubble atau yang dikenal dengan Microbubble Drag Reduction MBDR. Banyak faktor yang dapat mempengaruhi efisiensi dari penggunaan microbubble. Salah satunya adalah lokasi injeksi. Dalam tulisan ini kami mempelajari tentang lokasi injeksi microbubble yang efisien pada kapal model tongkang sepanjang 200 cm. Berdasarkan penelitian yang pernah dilakukan oleh para peneliti. Kami membandingkan dua lokasi yaitu lokasi after bow dan lokasi 5 cm after midship. Hasil pengujian menunjukkan bahwa lokasi after bow merupakan lokasi injeksi paling efektif pada kapal model. ...... Resistance are one of the most important factors in marine transportation technology. One method that can reduce the resistance on ship is Microbubble method or known as Microbubble Drag Reduction MBDR. Many factors that can affect the efficiency of microbubble. One of them is the location of the microbubble injector. In this paper we learn about the location of efficient microbubble injector on a barge ship model with 200 cm long. Based on research ever undertaken by the previous researchers. We compare with two locations that is after the bow and 5 cm after the midship. The test results show that the after the bow location is the most effective injector location on the barge ship model.

Abstrak :
ABSTRAK
Microbubble merupakan gelembung udara dengan diameter kurang dari 200 m di dalam air. Karakteristik unik yang dimiliki microbubble menyebabkan maraknya penggunaan microbubble dalam dunia industri. Penelitian mengenai performa dari generator microbubble dengan tabung silinder telah dilakukan. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh debit air, debit udara masuk, void fraction, pressure drop, dan jumlah lubang udara terhadap performa dari microbubble generator. Penelitian dilakukan dengan menerapkan sistem water loop dan menggunakan dua tipe microbubble generator. Tipe-tipe microbubble generator tersebut adalah tipe dengan 12 lubang udara dan 48 lubang udara pada set up alat uji. Setelah dilakukan penelitian, ukuran bubble yang dihasilkan serta tipe microbubble generator yang tepat ditemukan. Tipe 2 48 lubang menghasilkan persentase microbubble yang lebih banyak. Hal ini terbukti paling optimum pada keadaan Qa= 30 lpm dan Qu=0,6 lpm.

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ABSTRACT
Microbubbles are bubbles with the diameter size smaller than 200 m. The unique characteristics of microbubbles enhance its industrial utilization. The research about Microbubble Generator with a Spherical Body has been done. The objection of this research is to find the relevance between water flow rate, air flow rate, void fraction, pressure drop, and the number of air suction holes with the performance of microbubble generator. The research is done by applying water loop system and two types of microbubble generator. The types of microbubble generator are microbubble generator with 12 air suction holes and 48 air suction holes for the experimental set up. The results of this research are the size of bubbles which are generated and the recommended microbubble generator type. Microbubble generator with 48 air suction holes is the optimum generator of this research. The optimum condition is 30 lpm for the water flow value and 0,6 lpm for the air flow.

Abstrak :
Teknologi desalinasi perlu dimanfaatkan untuk memurnikan air garam yang tersedia, termasuk air laut untuk memenuhi kebutuhan air bersih yang semakin meningkat akibat pertumbuhan penduduk serta kebutuhan industry lainnya. Beberapa metode desalinasi, seperti metode termal, membran, dan pertukaran ion, terus dikembangkan tetapi masih memiliki beberapa kekurangan. Oleh karena itu, metode desalinasi alternatif baru dengan atomisasi droplet yang memanfaatkan fenomena air entrainment sedang dikembangkan. Studi ini bertujuan untuk menganalisis pengaruh dari diameter nozzle dan tekanan terhadap sudut semprotan untuk mengkarakterisasi kabut pada proses desalinasi dari hasil perancangan desain menggunakan microbubble. Studi ini menggunakan air laut yang direkayasa kadar garam sebesar 85 ppm, yang dipompa kemudian dialirkan melalui nozzle dengan diameter kecil menjadi droplet. Penggunaan microbubble test section juga digunakan untuk meningkatkan kinerja sistem. Data kuantitatif dari hasil eksperimen diperoleh dari alat ukur dan data kualitatif dalam bentuk video yang diperoleh dengan menggunakan kamera untuk diolah menjadi data kuantitatif dengan menggunakan pengolahan citra Image-J. Hasil studi menunjukkan bahwa tekanan mempengaruhi karakteristik semprotan air berbentuk kerucut penuh. Didapatkan konfigurasi sistem penyemprotan terbaik berdasarkan desain sistem dengan nozel berdiameter 0.2 mm pada tekanan 9 bar dengan nilai laju produksi 8.25 mL/30 menit dan tingkat kadar garam 48 ppm dengan penggunaan injeksi microbubble. Hasil penggunaan injeksi microbubble juga meningkatkan hasil sistem sebesar 16.4% laju produksi air dan 3.5% pengurangan kadar garam. sehingga penggunaan microbubble direkomendasikan untuk diterapkan. ......Desalination technology needs to be used to purify available salt water, including sea water to meet the increasing demand for clean water due to population growth and other industrial needs. Several desalination methods, such as thermal, membrane, and ion exchange methods, are being developed but still have some drawbacks. Therefore, a new alternative desalination method with droplet atomization utilizing the air entrainment phenomenon is being developed. This study aims to analyze the effect of the nozzle diameter and pressure on the spray angle to characterize the mist in the desalination process from the results of the design using microbubble. This study uses engineered seawater with a salt content of 85 ppm, which is pumped and then flowed through a nozzle with a small diameter into droplets. The use of microbubble test section is also used to improve system performance. Quantitative data from experimental results obtained from measuring instruments and qualitative data in the form of video obtained by using a camera to be processed into quantitative data using Image-J image processing. The results of the study show that pressure affects the characteristics of a full cone-shaped water spray. The best spraying system configuration was obtained based on the system design with a nozzle diameter of 0.2 mm at a pressure of 9 bar with a production rate of 8.25 mL/30 minutes and a salinity level of 48 ppm with the use of microbubble injection. The results of using microbubble injection also increased the system yield by 16.4% water production rate and 3.5% reduction in salt content. so the use of microbubble is recommended to be applied

Abstrak :

Keterpurukan kondisi pemenuhan kebutuhan air di dunia merupakan sebuah permasalahan yang harus segera diselesaikan. Menurut data WHO, pada tahun 2017, setidaknya 785 juta populasi dunia mengalami krisis air bersih. Krisis ini terus meningkat sampai diperkirakan pada tahun 2025, kurang lebih sampai setengah dari populasi dunia akan kesulitan memenuhi kebutuhan airnya. Indonesia juga merupakan negara dengan sumber daya air laut yang dapat dimanfaatkan. Teknologi pemurnian air laut, yang disebut juga desalinasi, merupakan solusi yang tepat dan perlu dikembangkan untuk menyelesaikan permsalahan ini. Teknologi desalinasi terkini memiliki luaran yang baik, namun masih menghadapi beberapa permasalahan seperti optimasi biaya dan efisiensi kerja. Penelitian diilakukan untuk membangun sebuah metode alternatif baru menggunakan microbubble dengan memanfaatkan kemampuannya dalam mengikat kontaminan. Rangkaian alat dirancang dengan konsep memasok uap air asin ke komponen air entrainment, sehingga uap air terkondensasi dan garam terikat oleh microbubble. Penelitian dilakukan untuk melengkapi penelitan yang sebelumnya telah dilakukan terhadap microbubble itu sendiri. Dengan merekayasa air laut dengan menggunakan air asin, dilakukan eksperimen dengan mengalirkan air asin melalui Nozzle berdiameter kecil sehingga terbentuk kabut. Variasi yang digunakan diantaranya, debit aliran bypasss rangkaian, jumlah nozzle, dan diameter nozzle. Direkam data pengukuran parameter fluida seperti tekanan, debit nozzle, dan spray angle. Data diambil menggunakan alat ukur elektronik dan pengambilan video untuk data image processing. Pengolahan data meliputi analisis efek variasi debit aliran bypass terhadap parameter fluida dan parameter nozzle. Hasil menunjukkan bahwa debit bypass berpengaruh terhadap tekanan dan debit aliran nozzle.

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The deterioration of the conditions for meeting the world's water needs is a problem that must be resolved immediately. According to WHO data, in 2017, at least 785 million of the world's population experienced a clean water crisis. This crisis continues to increase until it is estimated that by 2025, approximately half of the world's population will have difficulty meeting their water needs. Indonesia is also a country with seawater resources that can be utilized. Seawater purification technology, which is also called desalination, is the right solution and needs to be developed to solve this problem. The latest desalination technology has good results, but still faces several problems such as cost optimization and work efficiency. The research was carried out to build a new alternative method using microbubble by trapping water vapor so that condensation occurs. The series of tools is designed with the concept of supplying water vapor as a result of evaporation from the nozzle to the water entrainment component so that the water vapor condenses and forms a microbubble. The research was conducted to complement the research that had previously been carried out on the microbubble itself. By engineering seawater using saltwater, an experiment was carried out by passing the salt water through a small diameter nozzle to form a mist. The variations used include, bypass flow rate, number of nozzles, and nozzle diameter. Measurement data of fluid parameters such as pressure, nozzle discharge, and spray angle are recorded. Data is taken using electronic measuring instruments and video capture for image processing data. Data processing includes an analysis of the effect of variations in the bypass flow rate on fluid parameters and nozzle parameters. The results show that the bypass discharge affects the pressure and flow rate of the nozzle.

 

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

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

Abstrak :
This paper presents the efficiency improvement in aerobic wastewater treatment technology through the application of a microbubble generator (MBG) for aeration. Aeration using an MBG is accomplished through water circulation and does not need air compressors, making it more energy efficient than conventional aerators. The MBG aerobic system with the variations on liquid flow rate (Q1) and airflow rate (Qg) combination was tested using artificial wastewater with a typical composition of organic waste. Experimental data were evaluated by means of a simplified mathematical model to systematically compare different MBG schemes. The study confirmed that the soluble chemical oxygen demand (SCOD) removal efficiency was significantly affected by the Qg values. Lower Qg values were preferable because they tended to have higher soluble chemical oxygen demand (SCOD) removal efficiency. However, the microbubbles were less stable at lower Qg due to the high incidence of bubble collisions. The study concluded that for applications in an actual aerobic waste treatment pond, the positioning of the MBG in the pond had to be carefully designed to minimize the collision tendency.

Abstrak :
Hambatan kapal merupakan salah satu masalah krusial yang solusinya masih dicari sampai dengan saat ini. Microbubble Drag Reduction System (MBDRS) merupakan salah satu metode yang menjanjikan dikarenakan cara penerapannya yang mudah yaitu dengan cara menginjeksikan udara ke bagian bawah kapal. Udara yang diinjeksikan ke bagian bawah kapal diharapkan dapat memodifikasi properti lapisan batas yang turbulen yang nantinya kan mengurangi nilai hambatan gesek yang terjadi. Tujuan dari penelitian ini yaitu untuk mengetahui efek dari microbubble yang diinjeksikan kepada kapal model tipe SPB dengan dimensi utama L = 2000 mm, B = 521.6 mm dan T = 52.5 mm. Lokasi dan rasio injeksi paling optimum untuk tiap kecepatan didapat dengan cara melakukan uji tarik terhadap kapal model dengan penempatan alat injeksi pada 0.35L dari midship dan -0.025L dari midship pada rentang Fn 0.11-0.31 dan rasio injeksi antara 0.2-0.6. Hambatan yang terjadi pada kapal diukur secara presisi menggunakan load cell transducer. Hasil pengujian yang didapatkan menunjukkan bahwa penempatan injektor pada lokasi 0.35L dari midship menghasilkan nilai hambatan total yang paling rendah dibandingkan posisi -0.025L dengan rasio injeksi optimal untuk tiap kecepatan yang berbeda. ......Ship's resistance is one of the crucial problems that the solution is still being sought. Microbubble Drag Reduction System MBDRS which is applied by injecting air into the bottom of the hull is one of several promising active methods that have been developed because it is easy to apply. The injected air bubbles to the bottom if the ship are supposed to modify the turbulent boundary layer properties which in turn can lower the skin friction. The purpose of this study is to identify the effect of injected micro bubbles on a self propelled barge SPB 90 m type model with main dimensions L 2000 mm, B 521.6 mm and T 52.5 mm. The most optimum location and injection ratio at each speed can be obtained by conducting a towing test on a 2 meters air injected self propelled barge ship model in the after bow 0.35L and after midship 0.025L sections at Fn range between 0.11 to 0.31 and injection ratio between 0.2 to 0.6. The influence of micro bubbles injection location and bubble velocity will also be investigated. The ship model resistance was precisely measured by a load cell transducer. The test results show that after bow injection area gives the lowest drag reduction compared to the after midship injection area with different optimum injection ratio for each speed.