Hasil Pencarian  ::  Simpan CSV :: Kembali

"Polipropilena adalah polimer yang rentan terdegradasi. Pengaruh pemakaian dan penambahan kalsium karbonat pada limbah PP telah diteliti. Dari hasil penelitian dapat diketahui bahwa pemakaian polipropilena menyebabkan degradasi yang terbukti dengan densitas, modulus, dan kekuatan tarik limbah polipropilena (rPP) lebih tinggi dari resinnya (vPP). Akan tetapi degradasi tersebut tidak menimbulkan gugus fungsi baru pada rantai molekulnya. Penambahan kalsium karbonat pada limbah polipropilena akan meningkatkan modulusnya dan menurunkan kekuatan tarik dan elongasinya. Modulus komposit limbah polipropilena dan kalsium karbonat (rPP-CaCO3) menurun pada konsentrasi kalsium karbonat yang tinggi dan ukuran karbonat yang lebih besar. Keberhasilan proses pencampuran, dispersi dan distribusi partikel, memegang peranan vital dalam terciptanya komposit dengan karakteristik yang optimum. Kegagalan beberapa sampel pengujian disebabkan karena terjadinya aglomerasi partikel kalsium karbonat dalam matriks polimer.

---

Polypropylene is a degradation sensitive polymer. Effects of usage and addition of calcium carbonat to recycled polypropylnene were investigated. The investigation has found that usage of polypropylene cause a degradation on its molecule proved by increase in its density, modulus and tensile strength when recycled. The degradation does not occur new molecular bond or it doesn?nt change the molecular structure. The additon of calcium carbonate particles in recycled polypropylene increse its modulus but decrease its tensile strength and elongation. Modulus of the composite (rPP-CaCO3) decrese when the consentration of calcium carbonate added decrease and when the size of calcium carbonate particle increase. A good mixing process, good of dispersion and distribution of the particles, play an important role to make a composite with good carachteristics. The failure of some composite specimen are due to the aglomeration of calcium carbonate in the recycled polypropylene matrix."

"Penelitian ini bertujuan untuk menghilangkan kandungan besi dalam larutan sehinggapada akhirnya produk yang dihasilkan hanya mengandung nikel dan kobalt. Nikel dankobalt kemudian akan diolah dalam pembuatan suku cadang baterai lithium. Prosespenghilangan ini menggunakan pereaksi kalsium karbonat (CaCO3), dengan duaparameter yaitu pH dan konsentrasi. Parameter untuk pH adalah pH 1, pH 2, dan pH 3,sedangkan parameter lainnya adalah konsentrasi, yaitu konsentrasi 10% dankonsentrasi 15%. Karakterisasi residu dilakukan dengan dua alat, yaitu SEM EDS danXRD. Keduanya merupakan hasil semi kuantitatif. Untuk filtrat digunakan alat ICPyang datanya bersifat kualitatif. Data tersebut akan difokuskan pada tiga unsur utamayaitu besi, nikel, dan kobalt. Unsur-unsur tersebut akan dibandingkan berdasarkan datayang peneliti lakukan, dan dibandingkan dengan data di literatur. Kondisi optimal padapercobaan ini adaalah pada konsentrasi 10%, suhu 90oC, 2 jam pengadukan danpemanasan, pada pH 3.

---

This study was aiming to remove the iron content in the solution so in the end of the

product will be only nickel and cobalt contained. The nickel and cobalt then will be

process in making the lithium battery parts. This removal process using calcium

carbonate (CaCO3) as the reagent, with two parameters which are pH and

concentration. The parameter for pH is pH 1, pH 2, and pH 3, and the other parameter

is concentration which are 10% concentration and 15% concentration. The

characterization of residue will be done with two tools, which are SEM EDS and XRD.

Both of them are the semi quantitative result. For the filtrate it will used the ICP tools

which the data is qualitative. The data will be focusing on three main elements, which

are iron, nickel, and cobalt. Those elements will be compared based on the data that

the researcher got and compared with the literature data. The optimal condition on

removing the iron content is on 10% reagent concentration, 90oC, 2 hours of stirring

and heating, and at pH 3."

"Busa poliuretan mempunyai berbagai fungsi dalam dunia manufaktur, dan salah satu fungsinya ialah sebagai headliner pada mobil. Pembuatan headliner mobil membutuhkan properti busa yang rigid dan masih memiliki sedikit elongasi. Sedangkan pembuatan busa rigid membutuhkan zat aditif yang banyak dan relative mahal. Pada saat ini, dilakukan sebuah penelitian berupa pembuatan busa flexible yang dicampurkan dengan 4 gr kitosan dan 0,2 gr kalsium karbonat (CaCO₃) dalam 100 ml larutan 5% asam asetat (CH₃COOH dengan teknik dip coating dan menggunakan vacuum oven. Sampel yang digunakan adalah busa berdensitas 16 kg/m³ dan diberikan perlakuan dengan variable suhu dan waktu curing. Bedasarkan hasil yang diperoleh, perlakuan sampel dengan suhu 100^oC selama 120 menit adalah hasil yang terbaik. Sampel tersebut memiliki nilai ketahanan tarik maksimal dan elongasi yang tergolong baik serta kitosan dan CaCO₃ yang membungkus dengan rata semua pori pada permukaan busa serta memiliki hasil penilaian komposisi kimia dan temperatur dekomposisi yang dapat dikatakan paling baik daripada sampel lainnya. Sehingga dapat disimpulkan perlakuan tersebut dapat dilakukan penelitian atau produksi lanjutan.

---

Polyurethane foam has a major function in the world of manufacturing, and one of its functions as a headliner in cars. Making car headliners requires rigid foam properties and still has a little elongation. While making rigid foam requires a lot of additives and is relatively expensive. At this time, research was carried out consisting of making flexible foam mixed with 4 gr chitosan and 0.2 gr Calcium Carbonate (CaCO₃) in 100 ml of 5% acetic acid (CH₃COOH) solution with dip coating technique and using a vacuum oven. The sample used is foam density 16 kg/m3 and given with variable temperature and curing time.

Based on the results obtained, sample samples with a temperature of 100^oC for 120 minutes are the best results. This sample has ultimate tensile strength (UTS) and elongation which are classified as good with chitosan and CaCO₃ which wrap with all sizes on the foam surface and also the results of the chemical composition and decomposition temperature which is arguably the best of the other samples. It was agreed that discussions could be carried out for further research or production."

"Magnetisasi air sadah yang bertujuan menurunkan kesadahan air merupakan proses fisik guna mencegah terbentuknya kerak (CaCO3) pada sistem perpipaan. Campuran larutan Na2CO3 dan CaCl2 digunakan sebagai model air sadah sintetik guna mengamati pengaruh medan magnet terhadap pembentukan partikel CaCO3 dalam air sadah. Variabel proses meliputi waktu magnetisasi, kuat medan, dan konsentrasi larutan, sementara parameter yang akan diamati adalah jumlah deposit CaCO3, jumlah presipitasi total CaCO3, dan morfologi deposit CaCO3. Perbandingan parameter pengamatan dilakukan terhadap sampel yang dimagnetisasi dan sampel non-magnetisasi. Hasil percobaan menunjukkan adanya peningkatan laju pembentukan deposit dan presipitasi total CaCO3 pada sampel yang dimagnetisasi dibanding sampel non-magnetisasi. Peningkatan konsentrasi sampel larutan juga meningkatkan persentase kenaikan deposit yang terbentuk dengan adanya pengaruh medan magnet. Hasil foto mikroskop menunjukkan jumlah partikel CaCO3 yang terbentuk pada sampel yang dimagnetisasi lebih banyak dan ukuran partikelnya lebih kecil dan disertai adanya pembentukan agregat. Hasil uji XRD menunjukkan hanya kristal kalsit yang dominan. Namun demikian, terlihat adanya penurunan intensitas puncak kalsit yang cukup signifikan pada sampel yang dimagnetisasi yang menunjukkan adanya penurunan jumlah kristal kalsit dan peningkatan jumlah amorf pada deposit CaCO3 yang terbentuk. Hasil penelitian ini menunjukkan bahwa proses magnetisasi air sadah mendorong terjadinya penurunan ion Ca2+ dalam larutan akibat adanya peningkatan proses presipitasi total CaCO3.

---

Magnetic Field Effects on CaCO3 Precipitation Process in Hard Water. Magnetic treatment is applied as physical water treatment for scale prevention especially CaCO3, from hard water in piping equipment by reducing its hardness. Na2CO3 and CaCl2 solution sample was used in to investigate the magnetic fields influence on the formation of particle of CaCO3. By changing the strength of magnetic fields, exposure time and concentration of samples solution, this study presents quantitative results of total scale deposit, total precipitated CaCO3 and morphology of the deposit. This research was run by comparing magnetically and non-magnetically treated samples. The results showed an increase of deposits formation rate and total number of precipitated CaCO3 of magnetically treated samples. The increase of concentration solution sample will also raised the deposit under magnetic field. Microscope images showed a greater number but smaller size of CaCO3 deposits form in magnetically treated samples, and aggregation during the processes. X-ray diffraction (XRD) analysis showed that magnetically samples were dominated by calcite. But, there was a significant decrease of calcite?s peak intensities from magnetized samples that indicated the decrease of the amount of calcite and an increase of total amorphous of deposits. This result showed that magnetization of hard water leaded to the decreasing of ion Ca2+ due to the increasing of total CaCO3 precipitation process."

"Air secara alamiah mengandung ion-ion logam terlarut di dalamnya, salah satunya adalah ion Ca2+ yang dapat berpresipitasi dengan ion CO32- sehingga membentuk kerak. Anti-scale Magnetic Treatment (AMT) merupakan suatu metode yang dapat mengurangi pembentukan kerak tanpa mengubah sifat kimia dari air. Hingga saat ini, penelitian mengenai AMT dengan fluida dinamik masih terus dikembangkan. Data yang dihasilkan cukup lengkap, oleh karena itu diperlukan suatu pengembangan model matematis dari data-data yang dihasilkan dari penelitian sebelumnya, sehingga dapat diperkirakan hasil yang diperoleh pada suatu kondisi operasi tertentu. Data yang dihasilkan dari pengembangan model mempunyai harga yang mendekati hasil percobaan. Pengembangan model ini didapat waktu efektif magnetisasi dan variabel yang mempunyai pengaruh dominan terhadap presipitasi CaCO3, yaitu kecepatan alir dan konsentrasi larutan.

---

Naturally water contains of ionics metal which dissolved within, one of the ionic metal is calcium ion (Ca2+) which could precipitate with CO32- forming scale. Anti-scale Magnetic Treatment (AMT) is an alternative method that could reduce the forming scale without changing it's chemical properties. Now a days, experiment about AMT with dynamic fluid is still being developed. The datas from the experiment that have been conducted are sufficient, because of that, the needs of mathematics modelling from the data from previous reseach is important to forecast the result that will be obtained from certain operation conditions. The modelling data obtained from modelling development were closed enough with the experiment data. From this modelling development the most influenced precipitation CaCO3 which were the liquid flow and the cocentration of the solution."

"Anti scale magnetic treatment is a hard water treatment method using magnetic field to prevent (CaCO3) scale formation. This method has along and controversial history due to its unclear result of its mechanism and effectiveness. The results of researches, hypothesis, or explanations given by researchers were still partial and didn't satistfy yet in answering the magnetic phenomenon. There were three mechanisms which were suggested: ion mechanism. particle mechanism and Lorentz force eject. Hard water contain Ca2+ cations , CO3 anions, and CaCO3, particles. Magnetic field eject on CO3 (ion mechanism) modified hydration of ions which suppressed CaC03 precipitation, whereas magnetization CaCO; particle (particle mechanism) supported particles to attract to each other and increased nucleation rate. Both ion and particle mechanism are clearly showed by using static magnetization system, system where water were static to magnetic field Lorentz force caused ion shift in solution and known as by the magnetohydroidinamic phenomenon that forced nucleation of CaCO3. Lorentz force acts on every ions in hard water when it 's moving through applied magnetic field therefore dynamic magnetization system was needed to investigate this phenomenon. Particle mechanism and Lorentz force effect could increase CaCO, particle formation so that reduced concentration of Ca" ions in bulk solution, in the other hand ion mechanisms with its memory effect on CO3 could suppress CaCO, formation. Magnetization followed by deposition and filtration could increase effectiveness of AMT process."

"The aim of this study was to analyze the influence of toothpastes with or without green tea extract on the enamelhardness. Human teeth were used as specimens and surface enamel demineralization by soaking in 1% citric acid. Teeththat have been demineralized were applied with a toothpaste containing green tea extract with concentrations of up to 15%on the surface of the enamel teeth and then proceed with surface hardness measurement using Knoop system. The resultsshowed that soaking the teeth (enamel) in a demineralized solution has significantly decreased the hardness of toothenamel. Applications of toothpaste without (0%) and with green tea extract 5% or 10% or 15% on the demineralizedenamel surface have increased the enamel hardness significantly. However, no significant differences were seen betweenthe demineralized enamel and enamel applied with toothpaste containing green tea 5% or 10% or 15%. It was concludedthat the application of toothpaste containing 5% green tea extract was able to increase the hardness of demineralized enamel.Kekerasan Enamel Terdemineralisasi Melalui Penggunaan Pasta Gigi Mengandung Ekstrak Teh Hijau. Tujuandari penelitian ini adalah untuk menganalisis pengaruh pasta gigi tanpa atau dengan ekstrak teh hijau pada kekerasanenamel yang didemineralisasi. Gigi manusia digunakan sebagai spesimen dan permukaan enamel yang demineralisasidengan merendamnya di dalam asam sitrat 1%. Gigi yang telah didemineralisasi diaplikasi dengan pasta gigi yangmengandung ekstrak teh hijau dengan konsentrasi sampai 15% di permukaan enamel gigi dan dilanjutkan denganpengukuran kekerasan permukaan menggunakan sistem Knoop. Hasil penelitian menunjukkan bahwa perendaman gigidi dalam larutan demineralisasi telah secara signifikan menurunkan kekerasan enamel gigi. Selanjutnya, aplikasi pastagigi tanpa (0%) dan dengan ekstrak teh hijau 5% atau 10% ataupun 15% di permukaan enamel menghasilkan kekerasanenamel meningkat berbeda bermakna dari kekerasan enamel yang didemineralisasi saja. Namun, tidak terlihatperbedaan bermakna antara kekerasan enamel yang didemineralisasi dan enamel yang diaplikasi dengan pasta gigimengandung teh hijau 5% atau 10% ataupun 15%. Disimpulkan bahwa aplikasi pasta gigi mengandung ekstrak teh hijau5% telah dapat meningkatkan kekerasan enamel yang didemineralisasi."

"Maraknya isu tentang hemat energi dan ramah lingkungan menjadi topik hangat yang selalu diperbincangkan dan terus dikaji untuk dikembangkan. Isu energi begitu penting karena energi menjadi salah satu penopang ekonomi suatu bangsa. Di Indonesia, sumber energi baru dan terbarukan sangat melimpah untuk dikelola menjadi energi yang ramah lingkungan. Inovasi demi inovasi terus dikembangkan untuk menemukan metode yang tepat, berkualitas dan murah serta banyak tersedia di alam. Partikel nano calcium carbonate yang terbuat dari cangkang kerang adalah material ramah lingkungan yang tersedia melimpah di alam. Larutan yang bermuatan patikel nano calcium carbonate dapat digunakan sebagai solusi bagi upaya pengurangan hambatan DR pada aliran dalam pipa yang ramah lingkungan. Dalam penelitian ini, penggunaan partikel nano pada larutan fluida kerja air-etilen glikol dengan perbandingan 40:60. Konsentrasi partikel yang digunakan ialah 100 ppm, 300 ppm dan 500 ppm pada fluida kerja. Pengujian dilakukan pada alat uji yang dirancang horizontal dengan komponen sisem perpipaan yang menggunaan pipa spiral dengan P/Di 10.8 dan pipa bulat dengan diameter dalam 4 mm. Melalui pengujian yang dilakukan, perubahan nilai friction factor menjadi parameter terjadinya DR. Pada aliran laminar DR tertinggi pada pipa spiral sebesar 79.9 untuk konsentrasi 500 ppm dengan Re rsquo; 1500 dan DR pada aliran turbulen tertinggi pada pipa bulat yaitu 47 untuk konsentrasi 300 ppm serta pada Re rsquo; 2500.

---

The rise of energy saving issue and environmentally friendly become a trend topic that is always discussed and continue to be reviewed to be developed. The issue of energy is so important because energy becomes one of the economic support foundation of a nation. In Indonesia, new renewable energy sources are abundant to be managed into environmentally friendly energy. Innovations continues to be developed to find the right method, quality and cheap, widely available in nature. Calcium carbonate nano particles made of shellfish are environmentally friendly materials available in abundance in nature. The nano calcium carbonate nanoparticle solution can be used as a solution for reducing the drag DR in an environmentally friendly pipeline flow. In this study, the use of nanoparticles in aqueous solution of water ethylene glycol fluid with a ratio of 40 60. The particle concentration used is 100 ppm, 300 ppm and 500 ppm on the working fluid. The test is performed on a horizontally designed test with component of the piping system which uses a spiral pipe with P Di 10.8 and a circular pipe 4 mm of inner diameter. Through this test, the change of friction factor value becomes the parameter of the indicator of DR. In the highest DR laminar flow in the spiral pipe 79.9 for the 500 ppm concentration with Re 39 1500 and DR at the highest turbulent flow on the circular pipe are 47 for the 300 ppm concentration and at the Re 39 2500. "

"CaCO3 is friendly to both the environment and humans. For this reason, it is suitable to be applied in fluid transportation to enable more efficient flow. The objective of this study was to investigate the effect of CaCO3 on the flow in a pentagon spiral pipe. The working fluid was circulated into the test pipe with constant pressure by the compressor. The working fluid was produced by mixing pure water with CaCO3 nanoparticles, which have average diameter of 100 nm, in the concentration ratios of 100 ppm, 300 ppm and 500 ppm. The test pipe was a pentagon spiral pipe with the ratio P/Do 7.1, and a circular pipe with a 4 mm inner diameter was used for comparison. The highest drag reduction (DR) that occurred in the spiral pipe was 35% around Re' 4×104 with nanofluids concentration of 500 ppm, while the highest DR in the circular pipe was of 26% around Re’ 4×104. The results show that increasing the percentage of solid particles affects the properties of the working fluid, such as viscosity, density, pressure drop and DR. The effects of the change in fluid properties were also taken into account. These affect the damping phenomena in the near wall region, which gives friction factor reduction. Another benefit of the spiral pipe is that it prevents the sedimentation of nanoparticles."