Engineering Commons^™

An Analysis Of Capillary Flow In Finite Length Interior Corners, Samuel Shaw Mohler

Dissertations and Theses

We analyze the mathematical robustness of slow massively parallel interior corner flows in low gravity environments. An interior corner provides a preferential orientation in low gravity environments. This is a luxury usually only found on earth. It also provides a passive pumping mechanism due to geometry of a conduit. The driving force for this flow is a pressure difference due to local surface curvature gradients. An alternative reasoning is that due to the geometrical constraints the interior corner surface energy is unbounded below. This results in the liquid wicking into corners indefinitely. Interior corner flow's main quantity of interest is …

Extracting Microplastic From Anhydrous Beach Sediment Utilizing Relative Terminal Velocities, Grace Robertson, Jackson Schuler

Student Works

The primary intent of this research was to investigate and develop a method to extract microplastics from anhydrous beach sediment. Microplastic is found abundantly in coastal sea environments, including aqueous bottom sediment, and beach sediment (Sagawa, Kawaai, & Hinata, 2018). The scope of the microplastic extraction method in this case is limited to strictly the anhydrous beach sediment. The Venturi Effect and Burnoulli’s Principle have been utilized in the design of a nozzle with airflow that has been injected with a sediment and microplastic heterogenous mixture. A nozzle was designed to operate at the specific terminal velocity of sediment such …

Fixed Bottom Wind Turbine Wave-Wake Interaction, Ondrej Fercak

Dissertations and Theses

The interest and benefits of offshore wind energy has also brought along legitimate design challenges for engineers. Most notably, the complex interaction between wind and turbine is further complicated by the addition of dynamic ocean waves. This dynamic coupling between wind, wave, and turbine is not fully understood. Even small improvements in wind turbine performance are welcome, so characterizing a fundamental dynamic in offshore energy is necessary to optimize design. Experimentation and simulation have been used to characterize inflow and turbine wakes and separately, wind-wave interactions. But only simulations have just begun to look at the wind, wave, and turbine …

Issue 8: Contributors, Sukarno Abdulrachman

Online Journal of Space Communication

List of contributors for Issue 8.

Sudah Waktunya Menggunakan Ku-Band Di Indonesia, Prima Setiyanto Widodo

Online Journal of Space Communication

Sistem Komunikasi Satelit adalah salah satu sarana atau infrastruktur yang dapat digunakan untuk aplikasi broadband multimedia. Dalam dunia sistem komunikasi satelit, frekuensi C-band telah lama digunakan dan saat ini telah penuh. Dan telah lama pula dunia menerapkan frekuensi Ku-band untuk sistem komunikasi satelit karena dengan frekuensi ini aplikasi broadband bisa lebih baik digunakan (bandwidth lebih lebar). Selain keuntungan lainnya, yaitu terhindar dari interferensi dengan sistem microwave terestrial yang banyak memakai frekuensi C-band. Namun bagi Indonesia penggunaan frekuensi Ku-band ini memerlukan pengkajian yang cermat, karena frekuensi di atas 10 GHz. rentan terhadap hujan, terlebih hujan deras yang sering melanda Indonesia. Tulisan …

It Is Time To Use The Ku-Band In Indonesia, Prima Setiyanto Widodo

Online Journal of Space Communication

Satellite Communications Systems are infrastructures that can be used for broadband multimedia applications. In the communication satellite field, the C-band (4-6 GHz) frequencies have been used since the beginning and are now saturated. The Ku-band (11-18 GHz) has been used also for communication satellite systems, because with this frequency a bigger bandwidth can be applied. The Ku-band has other advantages, such as avoidance of interference with terrestrial microwave systems that often use the C-band frequency. However, for Indonesia, the use of the Ku-band needs a thorough examination because frequencies above 10 GHz are vulnerable to rain, especially heavy rain that …

Tulang Punggung Ip Pita Lebar Memakai Satelit Di Indonesia Dengan Beaya Rendah, Onno W. Purbo

Online Journal of Space Communication

Artikel ini menyajikan tentang beberapa tulang punggung berbasis IP yang beroperasi di Indonesia.

Pada dasarnya, jasa IP melalui VSAT yang digunakan bersama, seperti misalnya jasa DVB (Digital Video Broadcasting) nampaknya merupakan solusi murah yang menjadi favorit sebagai tulang punggung IP pita lebar melalui satelit, dibandingkan dengan pemecahan SCPC (Single Carrier Per Channel) yang biayanya lebih tinggi.

Pertanyaan-pertanyaan yang sering dikemukakan, seperti konfigurasi tipikal atau perusahaan mana yang memberikan jasa tersebut, juga diulas. Beberapa diantara jasa tersebut, khususnya jasa VSAT IP Satu Arah - Receive Only tidak memerlukan lisensi atau izin Pemerintah Indonesia.

Sebuah jasa VSAT DVB satu arah (receive only) …

Development Of An Indonesian Micro Satellite, Rakhim Yuba

Online Journal of Space Communication

Indonesia's geographical condition is a blessing, at the same time a challenge to the continuity of its national development. Its numerous islands, big and small, stretching from Sabang to Merauke makes it imperative for Indonesia to use satellites for communication and other applications purposes.

Low Cost Broadband Ip Satellite Backbone In Indonesia, Onno W. Purbo

Online Journal of Space Communication

This article will report on several IP-based satellite backbones in operation in Indonesia. Basically, shared VSAT IP service, such as Digital Video Broadcasting (DVB) service seems to be the favorite low cost solution for broadband IP satellite backbone compared to the more costly Single Channel Per Carrier (SCPC).

Answers to questions, such as typical configurations providing the service, will be described. Some of these services may be run without any government license. The receive-only IP VSAT service is one of these.

A one-way receive-only IP-based DVB VSAT service may be obtained for US $33-270 per month. Two-way DVB/RCS VSAT service …

Kerjasama Strategis Sistem Vsat Dalam Teknologi Informasi Perusahaan: Kasus Infocom, Rafdian Rasyid

Online Journal of Space Communication

Apakah VSAT (Very Small Aperture Terminals) bisa menjadi sistem pendukung bagi teknologi informarsi (TI) perusahaan? Atau, dapatkah VSAT memainkan peran strategis yang penting dalam mendukung bisnis?

Sangat jelas bahwa di Indonesia VSAT merupakan infrastruktur yang mutlak keberadaanya. Tidak dapat disangkal bahwa sampai saat ini Indonesia belum memiliki prasarana terestrial yang dapat mencakup daerah-daerah terpencil, bahkan kadang-kadang juga daerah metropolitan. Hanya VSAT-lah yang dapat menjangkaunya. Namun, hubungan apa yang dapat kita tarik antara eksistensi VSAT-VSAT dan teknologi informasi dalam lingkungan suatu perusahaan? Artikel ini mencoba menjawab hal itu. Kemudian, penulis akan membahas tantangan-tantangan apa yang dihadapi oleh operator-operator VSAT, serta pemecahan …

Strategic Alignment Of Vsat System In Corporate It: Infokom's Case, Rafdian Rasyid

Online Journal of Space Communication

Can VSATs play a significant strategic role in terms of supporting businesses? Can VSATs support corporate IT?

It is obvious that in Indonesia, VSAT is a must have infrastructure for business. Nobody can argue that Indonesia up to now does not have terrestrial infrastructures that can cover remote areas or even metropolitan areas. Only VSATs can reach them. However, what link can we make between the existence of VSATs and IT in the corporate environment? This article attempts to answer that. We will also discuss challenges faced by VSAT operators, and solutions that can be applied.

Indonesia's Vsat Industry And Role Of Csm Today And In The Future, Gregorius Parlindungan Hutahaean

Online Journal of Space Communication

PT Citra Sari Makmur, or "CSM," began its VSAT operations in 1989 and became the first VSAT operator for the public in Indonesia. In the beginning, VSATs were targeted mainly to the corporate market in Indonesia: entities that operated nationwide and needed online data communication for financial transactions, online integrated data bases and report consolidation.

CSM was founded and led by an Indonesian businessman with vision, Mr. Subagio Wirjoatmodjo, who is currently also a member of MASTEL's executive board. MASTEL is the Telecommunications Association of Indonesia.

Today, CSM as market leader is holding 64% market share among VSAT public operators …

Industri Vsat Di Indonesia, Dan Peranan Csm Saat Ini Dan Di Masa Depan, Gregorius Parlindungan Hutahaean

Online Journal of Space Communication

PT Citra Sari Makmur, atau "CSM", memulai pengoperasian VSAT pada tahun 1989, yang kemudian berkembang menjadi operator VSAT pertama di Indonesia.

Pada mulanya VSAT terutama ditujukan kepada pasar perusahaan (korporasi) di Indonesia: yakni badan-badan hukum yang beroperasi secara nasional dan membutuhkan komunikasi data on-line untuk transaksi-transaksi keuangannya, online integrated data base dan juga dalam konsolidasi laporan.

CSM dibangun dan dipimpin oleh seorang pengusaha Indonesia yang memiliki visi ke depan, Bapak Subagio Wirjoatmodjo, yang sekarang ini juga aktif sebagai anggota Dewan Pengurus Harian MASTEL (Masyarakat Telematika Indonesia, the Indonesian Infocom Society).

Saat ini CSM merupakan pelaku pasar yang menguasai 64% pangsa …

Bagaimana Membuat Indonesia Terhubung: Melayani Yang Belum Terlayani, Chrisma Albandjar, Hilman A. Rasyid

Online Journal of Space Communication

Sudah 126 tahun berlalu sejak Alexander Graham Bell untuk pertama kalinya menciptakan telepon, serta sekitar 50 tahun yang lalu Indonesia yang merdeka memiliki perusahaan teleponnya sendiri.

Namun, dewasa ini, di tahun 2004, penetrasi telepon (jumlah telepon setiap 100 penduduk) di Indonesia hanya 10,45 persen, termasuk sambungan telepon tetap maupun sambungan bergerak (seluler). Angka ini adalah angka yang dipublikasikan oleh Direktorat Jenderal Pos dan Telekomunikasi.Tulisan ini hendak menggambarkan masalah-masalah pokok di Indonesia dalam meningkatkan angka penetrasi telepon, serta beberapa solusi untuk mengatasinya.

Connecting Indonesia: Serving The Unserved, Chrisma Albandjar, Hilman A. Rasyid

Online Journal of Space Communication

It has been 126 years since Alexander Graham Bell invented the telephone and around 50 years since Indonesia had its own telephone company.

Unfortunately, the penetration of telephones in Indonesia today (2004), counting fixed as well as mobile telephone lines in use, is only 10.45% according to the figures published by the Directorate of Post and Telecommunications.

This paper will point out the inherent problems Indonesia has with regards to telephone penetration and take you through some of the solutions to overcome them.

Distance Education Via Satellite: An Early Case Study Of The Indonesian Distance Education Satellite System, Willard D. Shaw

Online Journal of Space Communication

In 1980, the U.S. Agency for International Development initiated the AID Rural Satellite Program (RSP) to explore the potential of telecommunications as a means of extending scarce expert resources and expanding educational opportunities to remote and rural areas. Building on simple, interactive, and inexpensive telephone-based technologies, the Program developed teleconferencing systems for use as a development tool. Three pilot projects-in Indonesia, the West Indies, and Peru-were implemented to test and demonstrate that audioteleconferencing could reliably and affordably support development activities in education, health and agriculture.

In Indonesia and the West Indies, distance education programs were established with national universities. Linking …

Perjalanan Telkom Dalam Mengoperasikan Satelit Komunikasi Untuk Melayani Kepulauan Indonesia, Tonda Priyanto

Online Journal of Space Communication

Pada tahun 1976 Indonesia menjadi negara ketiga di dunia yang mengoperasikan Sistem Komunikasi Satelit Domestik dengan menggunakan Satelit GSO, yakni sistem Palapa A. Sistem satelit ini memberikan layanan teleponi dan faksimil antarkota di Indonesia dan juga menjadi infrastruktur utama pendistribusian program televisi. Saat ini, TELKOM sudah mengoperasikan jaringan komunikasi satelit selama 28 tahun. Dalam rentang waktu itu, TELKOM mengalami berbagai penyempurnaan teknologi, peningkatan dalam jasa-jasa nilai-tambah, serta juga perubahan-perubahan dalam regulasi. Saat ini TELKOM mengoperasikan dua satelit, PALAPA B4 dan TELKOM-1 untuk memberikan layanan telephony trunking, yang juga mencakup untuk sistem-sistem seluler, dan berperan sebagai tulang punggung data dan Internet …

Historical Overview: The Journey Of Telkom In Operating Communications Satellites To Serve The Indonesian Archipelago, Tonda Priyanto

Online Journal of Space Communication

n 1976, Indonesia became the 3rd nation in the world operating a Domestic Satellite Communication System using GSO Satellites, the PALAPA A system. This satellite system provided telephony and facsimile services between cities in Indonesia and became the main TV program distribution infrastructure.

TELKOM* has been operating satellite communication networks for almost 30 years, TELKOM has experienced technology improvements, value added service improvements and also changes in regulations. Nowadays, TELKOM operates 2 satellites, PALAPA B4 and TELKOM-1, for telephony trunking for cellular systems and as data and Internet backbone throughout Indonesia. This paper is intended to describe the journey of …

Berani Menghadapi Tantangan Teknologi Satelit: Terobosan Nasional Dan Peran Indonesia Di Forum-Forum Internasional, Arnold Djiwatampu

Online Journal of Space Communication

Untuk menyegarkan ingatan kita, sistem satelit domestik Palapa merupakan terobosan teknologi untuk mencapai daerah-daerah terisolasi dan memicu kegiatan-kegiatan usaha.

INTELSAT mulai membuka cakrawala baru untuk komunikasi satelit internasional yang handal, dan Indonesia telah mengambil keputusan bijak untuk segera turut serta, meskipun dihadang berbagai kesulitan di bidang ekonomi.

Indonesia harus mengambil keputusan-keputusan yang penting pada waktu ITU WARC-ORB '85 dan '87 sejalan dengan kepentingan komunitas dunia dan kepentingan nasionalnya sendiri. Bekerja sama dengan operator-operator Mobile Satellite Service (MSS) lainnya, Indonesia mendapatkan persetujuan pada WRC-95 untuk memperbaiki pita frekuensi MSS yang terfragmentasi, serta tambahan alokasi di WRC-2003.

Indonesia ikut serta pula dalam …

Historical Overview: Planning And Development Of Indonesia's Domestic Communications Satellite System Palapa, Marwah Ibrahim

Online Journal of Space Communication

This paper is taken from the author's dissertation written in 1989, entitled The Application of Communications Satellite in Developing Countries: The Case of Indonesia.

Artikel ini merupakan ringkasan dari disertasi penulis berjudul The Application of Communications Satellite in Developing Countries: The Case of Indonesia yang ditulis pada tahun 1989 untuk meraih gelar doktor di American University, Washington. Secara ringkas artikel ini menggambarkan sejarah awal dari Sistem Sateli Komunikasi Domestik Palala, mencakup dari alasan-alasan perlunya Indonesia memiliki sistem satelit seperti itu serta sejarah ringkas pembelian hingga pelucuran satelit Palapa. Pada saat itu, keputusan untuk memiliki satelit sendiri merupakan keputusan yang berani, …

Historical Overview: Braving The Challenge Of Satellite Technologies: National Breakthroughs And Indonesia's Role In International Forums, Arnold Djiwatampu

Online Journal of Space Communication

At the time INTELSAT made available for the first time reliable international satellite communication in the 1960's, Indonesia made a wise decision to join the Consortium of Satellite-Using Nations, notwithstanding the economic hardships it posed to participate. Later in the 1970's, the launch of Indonesia's Palapa domestic satellite was a breakthrough technology for addressing isolated areas, and triggering business activities.

Indonesia had crucial decisions to make during ITU's WARC-ORB 1985 and 1987 regulatory deliberations in the interest of the global community and its own national interest. In cooperation with other Mobile Satellite Services (MSS) operators, Indonesia obtained an endorsement at …

Issue 8: From The Guest Editor, Sukarno Abdulrachman

Online Journal of Space Communication

Selamat Datang di edisi 8 dari majalah "Online Journal of Space Communication," yang merupakan Terbitan Khusus dengan tema "Peran Satelit dalam Pembangunan Nasional Indonesia."

Pada saat perkembangan teknologi satelit di dunia masih berada pada tahap sangat awal, Indonesia sudah menyadari bahwa penggunaan angkasa luar untuk keperluan damai pada umumnya, dan komunikasi melalui satelit pada khususnya, dapat berdampak sangat positif dan dapat berperan penting dalam pembanguna nasional Indonesia.

Indonesia sebagai negara kepulauan terbesar di dunia, dengan penduduk lebih dari 200 juta manusia yang tersebar tidak merata di antara ribuan pulau, menghadapi tantangan utama yaitu membangun, memelihara serta mengembangkan prasarana yang bermanfaat …

Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair

Publications and Research

Lightning strike protection (LSP) have recently been a newly developing field particularly with the emergence of graphene thin film integration into carbon fiber composite structures. This technology has a widespread application in airplanes, wind turbines, and other instruments which are susceptible to frequent lightning strikes. Electrical discharge of the instrument in a safe manner is vital for the safety of the passengers (in the case of flights) as well as the integrity of the aircraft structures because of their specific mechanical and structural properties, which are essential for their functioning. The purpose of the study is to fabricate graphene thin …

Design And Flight-Path Simulation Of A Dynamic-Soaring Uav, Gladston Joseph

Doctoral Dissertations and Master's Theses

We address the development of a dynamic-soaring capable unmanned aerial vehicle (UAV) optimized for long-duration flight with no on-board power consumption. The UAV’s aerodynamic properties are captured with the integration of variable fidelity aerodynamic analyses. In addition to this, a 6 degree-of-freedom flight simulation environment is designed to include the effects of atmospheric wind conditions. A simple flight control system aids in the development of the dynamic soaring maneuver. A modular design paradigm is adopted for the aircraft dynamics model, which makes it conducive to use the same environment to simulate other aircraft models. Multiple wind-shear models are synthesized to …

Modeling Of A Hybrid-Electric System And Design Of Control Laws For Hybrid-Electric Urban Air Mobility Power Plants, Sohail Bin Salam Lahaji

Doctoral Dissertations and Master's Theses

Advanced Air Mobility (AAM) is an emerging market and technology in the aerospace industry. These systems are being developed to overcome traffic congestion. The current designs make use of Distributed Electric Propulsion (DEP): either fully electric or hybrid electric. The hybrid engine system consists of two power sources: prime movers, such as turbine engines, and batteries. The hybrid systems offer higher range and endurance compared with the existing fully electric systems. Hybrid-electric power generation systems for AAM have different mission requirements when compared to systems used in automobiles. Therefore, there is a particular need to model hybrid-electric systems and the …

Fault Tolerant Deep Reinforcement Learning For Aerospace Applications, Christoph Elias Aoun

Doctoral Dissertations and Master's Theses

With the growing use of Unmanned Aerial Systems, a new need has risen for intelligent algorithms that not only stabilize or control the system, but rather would also include various factors such as optimality, robustness, adaptability, tracking, decision making, and many more. In this thesis, a deep-learning-based control system is designed with fault-tolerant and disturbance rejection capabilities and applied to a high-order nonlinear dynamic system. The approach uses a Reinforcement Learning architecture that combines concepts from optimal control, robust control, and game theory to create an optimally adaptive control for disturbance rejection. Additionally, a cascaded Observer-based Kalman Filter is formulated …

On The Local Heat Transfer Behavior Of Supercritical Carbon Dioxide, Neil Sullivan

Doctoral Dissertations and Master's Theses

A detailed study of the local heat transfer behavior of supercritical carbon dioxide (sCO2) is performed. Flows relevant to heat transfer devices, such as sCO2 heaters, recuperators, and internally cooled turbine blades are studied, with particular attention paid to data reduction methodology, and the use of appropriate reference quantities, nondimensionalizations, and correlations. Additionally, a semi-intrusive temperature measurement technique capable of obtaining highly spatially resolved temperature distributions is adapted for use in the challenging conditions of supercritical (SC) flow. SC fluids have proven difficult to study both experimentally and numerically due to dramatically changing thermodynamic and transport properties near the critical …

High-Order Positivity-Preserving L2-Stable Spectral Collocation Schemes For The 3-D Compressible Navier-Stokes Equations, Johnathon Keith Upperman

Mathematics & Statistics Theses & Dissertations

High-order entropy stable schemes are a popular method used in simulations with the compressible Euler and Navier-Stokes equations. The strength of these methods is that they formally satisfy a discrete entropy inequality which can be used to guarantee L₂ stability of the numerical solution. However, a fundamental assumption that is explicitly or implicitly used in all entropy stability proofs available in the literature for the compressible Euler and Navier-Stokes equations is that the thermodynamic variables (e.g., density and temperature) are strictly positive in the entire space{time domain considered. Without this assumption, any entropy stability proof for a numerical scheme …

Analysis Of A Non-Equilibrium Vortex Pair As Aircraft Trailing Vortices, Manuel Ayala

Mechanical & Aerospace Engineering Theses & Dissertations

Shortly after the roll-up evolution of the vortex sheet behind the wings of an aircraft, a coherent counter-rotating vortex pair emerges. Presence of this vortex pair in the downstream of an aircraft, creates unsafe conditions for other aircraft, especially near airport runways. Fundamental knowledge of the physics that govern the formation, duration and dissipation of aircraft wake vortices is desirable in order to improve aircraft operational safety. This study uses non-equilibrium pressure theory to develop an accurate model describing the physical behavior of the vortex pair created by an aircraft in the early to mid-field vortex regime. An isolated aircraft …

The Effect Of Through Thickness Reinforcement On Debonding Behavior Of Skin/Stringer Configuration, Yogaraja Sridhar

Mechanical & Aerospace Engineering Theses & Dissertations

Investigation of this study is to the determine the crack propagation and disbonding in the bonded region of the skin and stringer specimen. An adhesive layer has been used to bond the skin and stringer by using a heat press operation. After the bonding, a drilling method has been adopted to install the through thickness reinforcement in the specimen. The key role of the through thickness reinforcement is to increase the stiffness and strength of the panels and to prevent the crack propagation or disbonding of the panels. The reinforcement was installed in pure (Pristine) samples and in defect samples …