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Komputasi Dinamika Fluida pada T-Mikro Mixer Putri Ramadhany
Jurnal Rekayasa Proses Vol 11, No 2 (2017)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2499.741 KB) | DOI: 10.22146/jrekpros.26933

Abstract

Fluid diffusion can occur effectively if a high gradient concentration exists in every part of the fluid. This can be achieved by decreasing the cross section area of the channel into micro size. The miniatur size of micro mixer can be very effective for molecular diffusion in the mixing process. In this research, the modeling of mixing and heat transfer in the passive micro mixer was conducted. T-shaped mixer was chosen as micro mixer. Water was used as medium and passive tracers were added to differentiate water profile from two different inlets. Mixing and heat transfer profiles inside the T-micro mixer were observed. The computational fluid dynamics (CFD) modeling of mixing and heat transfer in the T-micro mixer was completed by ANSYS®. The effect of geometry and average input velocity of fluids on mixing process were observed. The result of this research included: (1) When the laminar flow is the dominant flow (Re is 25), the tracer mixing is not particularly seen. The tracer mixing is observed when the average velocity is increased (Re increases), (2) The heat flux to the wall (4.85x10-6 Watt/m2) occurred when T–micro mixer is no longer isothermal, (3) The scale–up to factor ten does not necessarily improve the mixing performance (Re is kept constant), and (4) When the shape of cross section is changed to circle (cross section area is kept constant), the mixing performance is not necessarily improved.ABSTRAKDifusi fluida dapat berjalan secara efektif jika memiliki gradien konsentrasi yang tinggi pada setiap bagian fluida. Hal ini dapat dicapai dengan memperkecil luas penampang pipa/unit proses menjadi ukuran mikro. Ukuran yang kecil pada mikro mixer menyebabkan difusi molekuler menjadi sangat efektif pada proses pencampuran. Pada penelitian ini, pemodelan untuk proses pencampuran dan perpindahan panas pada mikro mixer pasif dilakukan. Mikro mixer yang dipilih adalah jenis mixer berbentuk T (T –mikro mixer). Air digunakan sebagai medium dan tracer pasif kemudian dimasukkan untuk membedakan profil air yang berasal dari dua inlet yang berbeda. Profil pencampuran dan perpindahan panas dalam T–mikro mixer ini kemudian diamati. Pemodelan komputasi dinamika fluida pada T–mikro mixer dilakukan dengan menggunakan program ANSYS®. Efek geometri T – mikro mixer dan kecepatan fluida masuk diobservasi selama proses pencampuran. Hasil yang didapatkan dari penelitian ini adalah: (1) Pada saat kondisi aliran laminar dengan Re = 25, terlihat tidak ada proces pencampuran tracer (tracer mixing). Pencampuran tracer terlihat ketika laju alir dinaikkan (Re meningkat), (2) Flux perpindahan panas keluar sistem sebesar 4,85x10-6 Watt/m2ketika kondisi T – mikro mixer tidak lagi dijaga isotermal, (3) Peningkatan kinerja pencampuran juga tidak terlihat ketika T – mikro mixer dilakukan scale-up sepuluh kali lebih besar dari referensi (Re dijaga konstan), dan (4) Ketika bentuk penampang diganti dari segi empat menjadi lingkaran (luas penampang dijaga konstan), kinerja pencampuran tidak menjadi lebih baik.
The Effect of Hydrochloric Acid Solution and Glycerol on The Mechanical, Hydrate Properties and Degradation Rate of Biofilm from Ripe Banana Peels Putri Ramadhany; Justin Kenny Hardono; Maria Gabriela Kristanti
Jurnal Rekayasa Proses Vol 15, No 2 (2021)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.69435

Abstract

Banana peel is a biomass waste that has not been utilised optimally, despite its high starch content. Moreover, starch has potential as a raw material for biofilm or edible film production. This research focused on using the starch content from the mature banana peel to create a biofilm. Starch was extracted from the banana peel; then, it was hydrolyzed with a variation of hydrochloric acid solution (HCl) of 0.5 M (0, 2, 4 %-v/v Starch). Glycerol (0, 20, 40 %-w/w starch) was used as a plasticizer. It was found that the formulation of 4%-v/v HCl solution and glycerol 20%-w/w resulted in the highest biofilm’s tensile strength of 4.18 MPa. However, the elongation break percentage achieved the best result at 20,2% when the formulation of 0%-v/v HCl solution and 40%-w/w glycerol was applied. Increasing HCl solution and glycerol was proven to improve the biofilm’s solubility in the water, where 47.9% solubility was attained in the formulation of 40%-w/w glycerol and 4%-v/v HCl solution. The degradation rate of biofilm in the soil was measured using zero- and first-order kinetic rates. The zero-order resulted in the best model with a half-life time (t1/2) between 73 to 108 days.
The Influence of Glycerol Monostearate Concentration and Storage Condition on Tomato Powder’s Contents Using Foam Mat Drying Method Putri Ramadhany; Abigail Fern Pramana; Arabella Febiola; Tony Handoko
Reaktor Volume 21 No. 1 March 2021
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (58.043 KB) | DOI: 10.14710/reaktor.21.1.1-10

Abstract

Tomato is a seasonal horticultural product that has beneficial effects on human health. It contains a high concentration of lycopene and vitamin C. However, tomato production, which continues to increase in Indonesia, is not balanced with its consumption. Due to its high moisture content, harvested tomato relatively has a short shelf-life. Resultantly, the unconsumed tomato will end up being wasted. One way to prolong tomato’s shelf-life is by converting it into powder form. In this research, the tomato was shifted into tomato powder using a foam mat drying method. The weight ratio of GMS to tomato juice was varied: (1) 4%-w/w, (2) 5%-w/w, and (3) 6%-w/w. Tomato powder was then stored in two types of materials (sealed brown glass bottle and laminated aluminium foil (LAF) resealable zipper) and three conditions (refrigerator ( ± 4 ℃), room temperature (± 25.2 ℃) and sun-exposed  (± 30 ℃)). According to the results, foam mat drying could maintain the nutrients of the tomato powder. Increasing GMS larger than 5%-w/w had no big impact on reserving lycopene and vitamin C. At 5%-w/w GMS, tomato powder consisted of 1.09%/w/w moisture, 42.58 mg/100 g lycopene, and 123.28 mg/100 g vitamin C. It was found that moisture and vitamin C on tomato powder content was influenced by storage conditions, while lycopene content was influenced by storage material. Moisture content and vitamin C were best maintained at the sun-exposed condition and room temperature, respectively. While lycopene was best stored in the laminated aluminium foil (LAF) resealable zipper.
MODEL NUMERIK ABSORPSI GAS REAKSI ORDE DUA TAK REVERSIBEL Putri Ramadhany
JURNAL INTEGRASI PROSES VOLUME 7 NOMOR 2 DESEMBER 2018
Publisher : JURNAL INTEGRASI PROSES

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/jip.v7i2.4487

Abstract

Kontak antara fasa gas dan cair banyak sekali ditemui dalam industri kimia. Seringkali kontak yang terjadi disertai dengan reaksi kimia. Dalam absorpsi gas yang disertai dengan reaksi kimia dalam fasa cair, laju absorpsi gas dapat meningkat atau menurun secara signifikan. Akan tetapi terdapat beberapa kesulitan untuk mendeskripsikan kualitas perpindahan massa. Hal ini dikarenakan oleh keterbatasan numerik dalam menyelesaikan neraca massa kompleks. Tujuan penelitian ini adalah melakukan validasi model solusi numerik dengan membandingkan dua paramater yang dapat digunakan dalam menentukan kualitas perpindahan massa, yaitu: enhancement factor (EAo) dan bilangan Hatta (ϕ). Perpindahan massa antara fasa gas dan cair diasumsikan mengikuti model penetrasi Higbie. Model ini mengasumsikan perpindahan massa komponen A dari fasa gas menuju fasa cair yang mengandung komponen B dengan waktu tinggal (t) yang seragam. Lazarus Pascal Programming Language® digunakan untuk menyelesaikan persamaan diferensial parsial parabola tidak linear. Metode yang akan digunakan untuk memberikan solusi numerik adalah metode beda hingga (finite difference method). Pemodelan absorpsi gas ini berhasil dilakukan dengan 50 time steps dan diskrepansi sebesar 0,55%. Saat kondisi tunak, nilai enhancement factor (EAo) yang didapatkan pada berbagai bilangan Hatta sesuai dengan nilai yang dihitung berdasarkan persamaan teoritis dengan deviasi sebesar 3,5%. Model yang didapatkan kemudian digunakan untuk menentukan keefektifannya pada suatu studi kasus. Pada saat waktu tinggal 3,25 ms, nilai enhancement factor (EAo) yang didapatkan melalui solusi numerik lebih kecil dari solusi teoritis. Berdasarkan pemodelan, hal ini menunjukkan bahwa waktu tinggal belum menuju kondisi tunak.
Komputasi Dinamika Fluida pada T-Mikro Mixer Putri Ramadhany
Jurnal Rekayasa Proses Vol 11, No 2 (2017)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.26933

Abstract

Fluid diffusion can occur effectively if a high gradient concentration exists in every part of the fluid. This can be achieved by decreasing the cross section area of the channel into micro size. The miniatur size of micro mixer can be very effective for molecular diffusion in the mixing process. In this research, the modeling of mixing and heat transfer in the passive micro mixer was conducted. T-shaped mixer was chosen as micro mixer. Water was used as medium and passive tracers were added to differentiate water profile from two different inlets. Mixing and heat transfer profiles inside the T-micro mixer were observed. The computational fluid dynamics (CFD) modeling of mixing and heat transfer in the T-micro mixer was completed by ANSYS®. The effect of geometry and average input velocity of fluids on mixing process were observed. The result of this research included: (1) When the laminar flow is the dominant flow (Re is 25), the tracer mixing is not particularly seen. The tracer mixing is observed when the average velocity is increased (Re increases), (2) The heat flux to the wall (4.85x10-6 Watt/m2) occurred when T–micro mixer is no longer isothermal, (3) The scale–up to factor ten does not necessarily improve the mixing performance (Re is kept constant), and (4) When the shape of cross section is changed to circle (cross section area is kept constant), the mixing performance is not necessarily improved.ABSTRAKDifusi fluida dapat berjalan secara efektif jika memiliki gradien konsentrasi yang tinggi pada setiap bagian fluida. Hal ini dapat dicapai dengan memperkecil luas penampang pipa/unit proses menjadi ukuran mikro. Ukuran yang kecil pada mikro mixer menyebabkan difusi molekuler menjadi sangat efektif pada proses pencampuran. Pada penelitian ini, pemodelan untuk proses pencampuran dan perpindahan panas pada mikro mixer pasif dilakukan. Mikro mixer yang dipilih adalah jenis mixer berbentuk T (T –mikro mixer). Air digunakan sebagai medium dan tracer pasif kemudian dimasukkan untuk membedakan profil air yang berasal dari dua inlet yang berbeda. Profil pencampuran dan perpindahan panas dalam T–mikro mixer ini kemudian diamati. Pemodelan komputasi dinamika fluida pada T–mikro mixer dilakukan dengan menggunakan program ANSYS®. Efek geometri T – mikro mixer dan kecepatan fluida masuk diobservasi selama proses pencampuran. Hasil yang didapatkan dari penelitian ini adalah: (1) Pada saat kondisi aliran laminar dengan Re = 25, terlihat tidak ada proces pencampuran tracer (tracer mixing). Pencampuran tracer terlihat ketika laju alir dinaikkan (Re meningkat), (2) Flux perpindahan panas keluar sistem sebesar 4,85x10-6 Watt/m2ketika kondisi T – mikro mixer tidak lagi dijaga isotermal, (3) Peningkatan kinerja pencampuran juga tidak terlihat ketika T – mikro mixer dilakukan scale-up sepuluh kali lebih besar dari referensi (Re dijaga konstan), dan (4) Ketika bentuk penampang diganti dari segi empat menjadi lingkaran (luas penampang dijaga konstan), kinerja pencampuran tidak menjadi lebih baik.
The Effect of Hydrochloric Acid Solution and Glycerol on The Mechanical, Hydrate Properties and Degradation Rate of Biofilm from Ripe Banana Peels Putri Ramadhany; Justin Kenny Hardono; Maria Gabriela Kristanti
Jurnal Rekayasa Proses Vol 15, No 2 (2021)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.69435

Abstract

Banana peel is a biomass waste that has not been utilised optimally, despite its high starch content. Moreover, starch has potential as a raw material for biofilm or edible film production. This research focused on using the starch content from the mature banana peel to create a biofilm. Starch was extracted from the banana peel; then, it was hydrolyzed with a variation of hydrochloric acid solution (HCl) of 0.5 M (0, 2, 4 %-v/v Starch). Glycerol (0, 20, 40 %-w/w starch) was used as a plasticizer. It was found that the formulation of 4%-v/v HCl solution and glycerol 20%-w/w resulted in the highest biofilm’s tensile strength of 4.18 MPa. However, the elongation break percentage achieved the best result at 20,2% when the formulation of 0%-v/v HCl solution and 40%-w/w glycerol was applied. Increasing HCl solution and glycerol was proven to improve the biofilm’s solubility in the water, where 47.9% solubility was attained in the formulation of 40%-w/w glycerol and 4%-v/v HCl solution. The degradation rate of biofilm in the soil was measured using zero- and first-order kinetic rates. The zero-order resulted in the best model with a half-life time (t1/2) between 73 to 108 days.
Physicochemical Properties of Tomato Paste Fortified Functional Cheddar Cheese Putri Ramadhany; Anastasia Prima Kristijarti; Graciella Lorenz Susanto; Geraldo Prajna
Food ScienTech Journal Vol 5, No 1 (2023)
Publisher : University of Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33512/fsj.v5i1.15975

Abstract

The aim of this research is to fortify cheddar cheese’s nutritional value by adding tomato paste. This study transformed ultra-heat treatment (UHT) milk into cheese through cheddaring. Tomato paste was added at 5 g/L, 10 g/L, and 15 g/L during the first curd formation, together with calcium chloride (CaCl2). The type of rennet (animal and microbial) was varied at 0.25 ml/L of milk. Ripening was done in one month at 4°C. According to this study, animal rennet formed curd better than microbial rennet. The addition of tomato paste slightly decreases the curd formation, with approximately 0.37 % reduction per 5 gram of tomato paste. Increasing tomato paste to 15 g/L would increase lycopene to 0.993 – 0.996 mg/100 g. The cheese produced was categorized as extra-hard and low-fat based on the percentage of Moisture Non-Fat Basis (MNFS) and Fat on Dry Matter (FDM). The addition of tomato paste reduced the pH value, resulting in increased firmness and hardness and decreased chewiness and springiness.