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"Model Oksidasi Sikloheksana Tunak untuk Produksi Minyak Ketone-Alcohol (K-A). Oksidasi sikloheksana adalah salah satu reaksi penting dalam industri petrokimia dimana produk utamanya adalah senyawa intermediate untuk produksi nylon-6 dan nylon-6,6. Sebagian besar hasil produksi sikloheksana dikonversi secara komersial menjadi campuran sikloheksanon dan sikloheksanol (dikenal dengan nama minyak K-A) dengan oksidasi katalitik. Minyak K-A adalah bahan baku untuk produksi asam adipat dan kaprolaktam. Bila kandungan sikloheksanol dalam minyak K-A lebih tinggi daripada sikloheksanon, maka akan lebih menguntungkan kalau dikonversi menjadi asam adipat. Bila sebaliknya, maka konversi lebih lanjut menjadi kaprolaktam akan lebih disukai. Model reaksi oksidasi sikloheksana kondisi tunak dalam reaktor tangki berpengaduk telah dikembangkan dan diselesaikan dalam penelitian ini. Model tersebut didasarkan pada neraca massa dan perpindahan massa dengan memanfaatkan persamaan kinetika. Model dalam persamaan aljabar non-linear kemudian diselesaikan dengan metode optimisasi pemrograman non-linear. Keuntungan metode ini yaitu bahwa hubungan antar variabel dapat lebih dipahami dan penyelesaian terhadap model akan lebih cepat diperoleh. Manfaat hasil penelitian dapat dimanfaatkan untuk tahapan perancangan proses seperti penentuan dimensi reaktor maupun penentuan kondisi operasi.

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Cylohexane oxidation is of great industrial importance in the production of intermediates for the manufacture of nylon- 6 and nylon-6,6. Most cyclohexane is commercially converted into a cyclohexanone?cyclohexanol mixture (known as K-A oil) by catalytic oxidation. K-A (Ketone-Alcohol) oil is then used as a raw material for adipic acid and caprolactam production. Practically, if the cyclohexanol content of KA oil is higher than that of cyclohexanone, it is more profitable to convert it into adipic acid; otherwise caprolactam production is more likely. The steady state cyclohexane oxidation reaction model in a stirred tank reactor for K-A oil production is presented and solved in this paper. The model was derived based on the mass balance and mass transfer equations using the kinetic equation. The set of algebraic equations was solved using non linear programming. The advantage of this method is that the relationship among variables can be better understood and an appropriate solution to the equation set can be obtained more quickly. Simulation results are particularly useful for process design such as in determining reactor dimensions and operating conditions."

"The investigation of adsorption isotherms is a prime factor in the ongoing development of adsorption cycles for a spectrum of advanced, thermally-driven engineering applications, including refrigeration, natural gas storage, and desalination processes. In this work, a novel semi-empirical mathematical model has been derived that significantly enhances the prediction of the steady state uptake in adsorbent surfaces. This model, a combination of classical Langmuir and a novel modern adsorption isotherm equation, allows for a higher degree of regression of both energetically homogenous and heterogeneous adsorbent surfaces compared to several isolated classical and modern isotherm models, and has the ability to regress isotherms for all six types under the IUPAC classification. Using a unified thermodynamic framework, a single asymmetrical energy distribution function (EDF) has also been proposed that directly relates the mathematical model to the adsorption isotherm types. This fits well with the statistical rate theory approach and offers mechanistic insights into adsorption isotherms."

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Computational Fluid Dynamics (CFD) merupakan metode analisis numerik aliran fluida, perpidahan panas, dan fenomena terkait. Simulasi CFD seringkali membutuhkan waktu yang lama dan biaya komputasi yang mahal. Ini disebabkan oleh kompleksitas persamaan atur yang mendasari perilaku aliran. Dewasa ini, Model berbasis data (Data driven model) telah mendorong perkembangan pada banyak disiplin sains dan teknik, termasuk CFD. Melalui model berbasis data, orde dari persamaan atur dapat direduksi sehingga menghasilkan reduced order model (ROM). Penelitian ini bertujuan untuk menjelaskan algoritma dasar ROM untuk menyelesaikan kasus aliran menggunakan library ITHACA-FV. Kasus aliran fluida yang menjadi domain adalah aliran stedi tak mampu mampat Navier-Stokes pada backward-facing step. Kemudian solusi FOM dan ROM dibandingkan. Pada simulasi ROM mode 1 pada kasus backward-facing step terdapat error rata-rata sebesar 2,730% untuk data kecepatan dan 0,113% untuk data tekanan. Sedangkan simulasi ROM mode 3 pada kasus yang sama memiliki error rata-rata 1,085% untuk data kecepatan dan 0,058% untuk data tekanan.

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Computational Fluid Dynamics (CFD) is a method of numerical analysis of fluid flow, heat transfer, and related phenomena. CFD simulation often takes a long time and is computationally expensive. This is due to the complexity of the governing equations that underlie flow behavior. Fluid flow is governed by the Navier-Stokes equation which is non-linear and generally produces a random behavior called turbulence. Today, Data driven models have made developments in many scientific and engineering disciplines, including CFD. Through a data-based model, the order of the governing equations can be reduced to produce a reduced order model (ROM). This study aims to explain the basic ROM algorithm to solve fluid flow cases through the ITHACA-FV library. The fluid flow case that becomes the domain is the steady-state Navier-Stokes incompressible flow in the backward-facing step. Then the FOM and ROM solutions are compared. ROM mode 1 simulation has average error of 2.730% for velocity and 0.113% for pressure data. ROM mode 3 simulation has an average error of 1.085% for speed data and 0.058% for pressure data.

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"Computational Fluid Dynamics (CFD) merupakan metode analisis numerik aliran fluida, perpidahan panas, dan fenomena terkait. Simulasi CFD seringkali membutuhkan waktu yang lama dan biaya komputasi yang mahal. Ini disebabkan oleh kompleksitas persamaan atur yang mendasari perilaku aliran. Dewasa ini, Model berbasis data (Data driven model) telah mendorong perkembangan pada banyak disiplin sains dan teknik, termasuk CFD. Melalui model berbasis data, orde dari persamaan atur dapat direduksi sehingga menghasilkan reduced order model (ROM). Penelitian ini bertujuan untuk menjelaskan algoritma dasar ROM untuk menyelesaikan kasus aliran menggunakan library ITHACA-FV. Kasus aliran fluida yang menjadi domain adalah aliran stedi tak mampu mampat Navier-Stokes pada backward-facing step. Library ITHACA yang menjadi dasar simulasi ROM dianalisis. Kemudian solusi FOM dan ROM dibandingkan. Pada simulasi ROM mode 1 pada kasus backward-facing step terdapat error rata-rata sebesar 2,730% untuk data kecepatan dan 0,113% untuk data tekanan. Sedangkan simulasi ROM mode 3 pada kasus yang sama memiliki error rata-rata 1,085% untuk data kecepatan dan 0,058% untuk data tekanan.

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Computational Fluid Dynamics (CFD) is a method of numerical analysis of fluid flow, heat transfer, and related phenomena. CFD simulation often takes a long time and is computationally expensive. This is due to the complexity of the governing equations that underlie flow behavior. Fluid flow is governed by the Navier-Stokes equation which is non-linear and generally produces a random behavior called turbulence. Today, Data driven models have made developments in many scientific and engineering disciplines, including CFD. Through a data-based model, the order of the governing equations can be reduced to produce a reduced order model (ROM). This study aims to explain the basic ROM algorithm to solve fluid flow cases through the ITHACA-FV library. The fluid flow case that becomes the domain is the steady-state Navier-Stokes incompressible flow in the backward-facing step. The ITHACA library on which the ROM simulation is based is analyzed. Then the FOM and ROM solutions are compared. ROM mode 1 simulation has average error of 2.730% for velocity and 0.113% for pressure data. ROM mode 3 simulation has an average error of 1.085% for velocity and 0.058% for pressure data.

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"The present study investigated the phenol utulization kinetics of a pure culture of an indigenous pseudomonas fluorescence under steady state and non-steady state (washout) conditions..."

"Telah dibuat alat pengukur daya hantar buatan/bahan yang mengutamakan komponen lokal yang mudah di dapat di pasaran. Metode pengukuran yang digunakan adalah metode ''steady state''. Bahan padat dibuat sampel dengan berbentuk silinder berdiameter 10 cm dan variasi tebal 1 cm, 1,5 cm, dan 2 cm. Kalibrasi dilakukan dengan menggunakan aluminium yang memiliki nilai konduktivitas standard k (tebal referensi Holman, 1963) sebesar (137-210) watt/m C. Sedangkan konduktivitas panas k aluminium hasil percobaan sebesar (145-197) watt/m C. Dengan demikian hasil uji kalibrasi menunjukkan bahwa alat dapat bekerja dengan baik dan memberikan hasil yang akurat. Uji pengukuran terhadap sampel batu Gamping dari Wanagama, Wonosari memberikan nilai konduktivitas panas k sebesar 30,25 watt/m C (standard (2-3,4) watt/m C), dan pengukuran terhadap terhadap sampel batu pasir dari daerah Godean memberikan nilai konduktivitas panas k sebesar 16 watt/m C (standard (1,5-4,2) watt/m C). Hal ini menunjukkan jenis dan komposisi atau campuran batuan tersebut berbeda terhadap sampel referensi. "

"This book introduces finite difference methods for both ordinary differential equations (ODEs) and partial differential equations (PDEs) and discusses the similarities and differences between algorithm design and stability analysis for different types of equations. A unified view of stability theory for ODEs and PDEs is presented, and the interplay between ODE and PDE analysis is stressed. The text emphasizes standard classical methods, but several newer approaches also are introduced and are described in the context of simple motivating examples. The book is organized into two main sections and a set of appendices. Part I addresses steady-state boundary value problems, starting with two-point boundary value problems in one dimension, followed by coverage of elliptic problems in two and three dimensions. It concludes with a chapter on iterative methods for large sparse linear systems that emphasizes systems arising from difference approximations. Part II addresses time-dependent problems, starting with the initial value problem for ODEs, moving on to initial boundary value problems for parabolic and hyperbolic PDEs, and concluding with a chapter on mixed equations combining features of ODEs, parabolic equations, and hyperbolic equations. The appendices cover concepts pertinent to Parts I and II. Exercises and student projects, developed in conjunction with this book, are available on the book webpage along with numerous MATLAB m-files.Readers will gain an understanding of the essential ideas that underlie the development, analysis, and practical use of finite difference methods as well as the key concepts of stability theory, their relation to one another, and their practical implications. The author provides a foundation from which students can approach more advanced topics and further explore the theory and/or use of finite difference methods according to their interests and needs."

"ABSTRAKPenelitian ini menganalisis faktor-faktor yang memengaruhi penerimaan Negara dari kegiatan usaha hulu migas di Indonesia. Dalam penelitian ini akan dijabarkan perhitungan kontrak PSC secara matematis dan penerapannya secara aktual di lapangan. Penelitian menunjukkan bahwa dalam periode 2010-2014 terjadi peningkatan realisasi penerimaan migas secara nasional akan tetapi terdapat penurunan kontribusi penerimaan migas per Kontraktor Kontrak Kerja Sama yang menggunakan perjanjian Production Sharing Contract. Penemuan lainnya adalah persentase penerimaan Negara terhadap penjualan yang diterima oleh Indonesia semakin mengalami penurunan dari tahun 2010-2014, dikarenakan penjualan yang tidak bertumbuh dengan konstan, tingkat cost recovery sebagai biaya pengurang pendapatan yang terus mengalami peningkatan, dan penurunan produksi lifting pada periode yang sama.

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ABSTRACT

This study analyzes the factors that affect state revenue from oil and gas upstream activities in Indonesia. In this research, we will mathematically describe the calculation of PSC and the actual implementation in the field. Research shows that in the 2010-2014 period there was an increase realization of national oil and gas revenues but there is a decrease in the contribution of oil and gas revenues per Sharing Contractor who use agreements Production Sharing Contract. Another discovery is the percentage of state revenue to sales received by Indonesia increasingly decreased from 2010-2014, due to the sales not significantly growing, the level of cost recovery as a cost-reducing revenues continued to increase, and decrease of lifting production in the same period."