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2021

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Full-Text Articles in Engineering

Indonesia's Vsat Industry And Role Of Csm Today And In The Future, Gregorius Parlindungan Hutahaean Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 Jul 2021

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 …


Liner Sailing Speed Optimization Considering Wind And Waves, Zhaokun Wei, Xinlian Xie, Tiantian Bao Jul 2021

Liner Sailing Speed Optimization Considering Wind And Waves, Zhaokun Wei, Xinlian Xie, Tiantian Bao

Journal of Marine Science and Technology–Taiwan

This paper proposes a new sailing speed optimization problem considering sea conditions such as wind and waves for a container shipping company. Since wind and waves, as exterior factors, can reduce speed, more power is employed as compensation to maintain regular service frequency and avoid delay, resulting in additional bunker consumption and higher cost. Hence, it is necessary to optimize the sailing speed according to the wind and waves. A power model was built to determine the reduced speed caused by the wind and waves for quantifying the speed reduction. On the basis of the proposed model, we developed a …


A Bilevel Mathematical Approach For The Empty Container Repositioning Proble With A Sharing And Exchanging Strategy In Liner Shipping, Dung-Ying Lin, Chieh-Ju Juan Jul 2021

A Bilevel Mathematical Approach For The Empty Container Repositioning Proble With A Sharing And Exchanging Strategy In Liner Shipping, Dung-Ying Lin, Chieh-Ju Juan

Journal of Marine Science and Technology–Taiwan

In the maritime industry, the management of empty containers is a significant issue whose costs account for a large proportion of the total world fleet running costs. To reduce repositioning activities and increase cost effectiveness, this paper proposes a solution framework considering empty container sharing and exchanging strategies to coordinate the shipping lines in a maritime transportation network. The proposed solution framework considers an empty container matching platform company and a group of shipping lines in a given shipping network. Because of the interactive relationship between the two parties, the proposed problem is formulated as a bilevel programming problem, and …


Investigating Model Solution Correctness For Parameter Uncertainty In Both Objective Function And Constraints, Shangyao Yan, Sin-Siang Wang, Chun-Yi Wang Jul 2021

Investigating Model Solution Correctness For Parameter Uncertainty In Both Objective Function And Constraints, Shangyao Yan, Sin-Siang Wang, Chun-Yi Wang

Journal of Marine Science and Technology–Taiwan

To resolve engineering management problems encountered in the real world, optimization models are usually formulated with some parameter assumptions. Parameter uncertainty, which may arise due to changes in the environment or human error, may thus be incorporated into the objective function and the constraints. However, to simplify the modeling, the values of these parameters are usually set or projected as deterministic values. It is no wonder that the modelling results based on these inaccurate parameters are neither correct nor reliable. Thus, it is important to examine the correctness of the model results in relation to parameter uncertainty. This study aims …


Modular Design And Implementation Of An Automatic Power Factor Regulator For Energy Savings On Fishing Vessels, Chien-Hsing Lee, Shih-Hsien Hsu, Joe-Air Jiang Jul 2021

Modular Design And Implementation Of An Automatic Power Factor Regulator For Energy Savings On Fishing Vessels, Chien-Hsing Lee, Shih-Hsien Hsu, Joe-Air Jiang

Journal of Marine Science and Technology–Taiwan

This study describes the experiences of modular design and implementation of an automatic power factor regulator for improving energy efficiency on Taiwanese longline fishing vessels. The load capacities of such vessels are typically divided into three categories, depending on the gross tonnage or fish carrying capacity: less than 100 kW, from 100 kW to less than 250 kW, and larger than 250 kW. For attaining proper power factor improvement, a compensation unit with a total of 30 kVar, 60 kVar and 90 kVar was sized and assembled with capacitors of 10, 15 and 20 kVar to enable control within 12 …


Key Risk Factors Influencing Harbor Tugboat Operations For Kaohsiung Port, Wen-Jui Tseng, Ji-Feng Ding, Chia-Ming Liu, Liou-Yuan Li Jul 2021

Key Risk Factors Influencing Harbor Tugboat Operations For Kaohsiung Port, Wen-Jui Tseng, Ji-Feng Ding, Chia-Ming Liu, Liou-Yuan Li

Journal of Marine Science and Technology–Taiwan

The harbor tugboat operation is a very important business and process of Kaohsiung port. To ensure the safety of harbor tugboat operations and to reduce the occurrence of accidents, it is an important issue to conduct a risk assessment of tugboat operations for Kaohsiung port. Hence, the main purpose of this paper is employ the analytic hierarchy process (AHP) method to evaluate key risk factors influencing the harbor tugboat operations for Kaohsiung port. At first, a total of three evalu-ation dimensions with 14 preliminary risk factors are gener-ated from literature and interviews of tugboat captains. We then applied the steps …


Free Vibration Analysis Of A Free-Free Single-Tapered Beam Carrying Arbitrary Concentrated Elements Using Modified Mode-Superposition Method (Mmsm), Chia-Chin Wu Jul 2021

Free Vibration Analysis Of A Free-Free Single-Tapered Beam Carrying Arbitrary Concentrated Elements Using Modified Mode-Superposition Method (Mmsm), Chia-Chin Wu

Journal of Marine Science and Technology–Taiwan

The literature contains scant information on the free vibration analyses of the loaded single-tapered beams (STBs) (i.e., STBs carrying concentrated elements (CEs)) Furthermore, even when such studies have been performed, they generally only consider the case of constrained (e.g., free-clamped (F-C)) beams. In other words, the problem of unconstrained (e.g., free-free (F-F)) loaded STBs has not yet to be addressed. Thus, the present study employs the modified mode-superposition method (MMSM) to investigate the free vibration characteristics of the F-F loaded STB carrying arbitrary various CEs. The investigation focuses particularly on the natural frequencies and mode shapes of the rigid-body motions …


Optimum Design Of The Underwater Discharge System Based On Surrogate Modeling, Jisang Ha, Myung-Il Roh, Seung-Ho Ham, Sung-Jun Lee Jul 2021

Optimum Design Of The Underwater Discharge System Based On Surrogate Modeling, Jisang Ha, Myung-Il Roh, Seung-Ho Ham, Sung-Jun Lee

Journal of Marine Science and Technology–Taiwan

Underwater vehicles are equipped with a device for discharging projectiles, called the underwater discharge system. Because these vehicles have limited space, many studies have attempted to reduce the volume of the underwater discharge system while improving its performance. However, owing to the characteristics of the system, the occupied volume and performance conflict with each other. Therefore, minimizing the occupied volume while satisfying the required performance criteria is the most significant requirement in the design stage. To address this, an optimization problem for the underwater discharge system was mathematically formulated and solved using multi-objective genetic algorithms. Additionally, we proposed a method …


An Analysis Of Key Influencing Factors On Island Tourism Revisit Intentions – Evidence From The Matsu Islands, Chun-Chieh Wang, Hsiao-Chuan Liu, Hsuan-Shih Lee, Cheng-Chi Chung Jul 2021

An Analysis Of Key Influencing Factors On Island Tourism Revisit Intentions – Evidence From The Matsu Islands, Chun-Chieh Wang, Hsiao-Chuan Liu, Hsuan-Shih Lee, Cheng-Chi Chung

Journal of Marine Science and Technology–Taiwan

Sightseeing and tourism not only brings economic benefits to the local community but also drive the development of related industries. In 1992, when the Matsu’s battlefield mission was dissolved, tourism became one of the key development strategies to boom the region. Although the number of visitors to Matsu Islands has risen significantly in recent years, how to increase the island’s willingness to revisit the island has been an important issue. Since local tourism has its own characteristics, island tourism marketing strategies should be different. Many previous studies have quantified the relationship between tourism area satisfaction and willingness to revisit, but …


3d Numerical Simulation Of Kuroshio-Induced Wake Near Green Island, Taiwan, Tien-Hung Hou, Jen-Yi Chang, Chia-Cheng Tsai, Tai-Wen Hsu Jul 2021

3d Numerical Simulation Of Kuroshio-Induced Wake Near Green Island, Taiwan, Tien-Hung Hou, Jen-Yi Chang, Chia-Cheng Tsai, Tai-Wen Hsu

Journal of Marine Science and Technology–Taiwan

In this research, Kuroshio-induced vortex shedding in the lee of Green Island was numerically studied using the three-dimensional Princeton Ocean Model. The temporal and spatial characteristics of the vortex street were analyzed at different tidal levels, wind fields and water depths. The nu-merical results were validated by comparing with in-situ measurements from the Green Island tidal station, shipboard acoustic doppler current profiler (ADCP), conductivi-ty-temperature-depth (CTD) profiler, and moderate resolution imaging spectroradiometer (MODIS) satellite image datasets. Also, the three-dimensional results of velocity, temperature, and salinity fields were compared well with observational data. Furthermore, the influence depths of the wind effect and …


Intelligent Fuzzy Control With State-Derivative Feedback For Takagi-Sugeno Fuzzy Stochastic Singular Systems, Wen-Jer Chang, Kuang-Yow Lian, Cheung-Chieh Ku, Che-Lun Su Jul 2021

Intelligent Fuzzy Control With State-Derivative Feedback For Takagi-Sugeno Fuzzy Stochastic Singular Systems, Wen-Jer Chang, Kuang-Yow Lian, Cheung-Chieh Ku, Che-Lun Su

Journal of Marine Science and Technology–Taiwan

This document deals with the problem of passive fuzzy controller design with the state-derivative feedback approach for the nonlinear stochastic singular systems. Recently, the singular systems have a greater focus on literature because they can keep more physical system characteristics than conventional systems. At first, the Takagi-Sugeno fuzzy stochastic singular models are used to represent the nonlinear stochastic singular systems. Then, the state-derivative feedback approach and parallel distributed compensation method are employed to design the passive fuzzy controllers. In the design process, the Lyapunov stability conditions are developed subject to multiple performance constraints, including the passivity constraint and decay rate …


Gis-Based Landslide Susceptibility Mapping Using Logistic Regression, Instability Index, And Support Vector Machine: Case Study Of The Jingshan River, Taiwan, Hsun-Chuan Chan, Yu-Chin Chen, Jung-Tai Lee, Yu-Ting Wen Jul 2021

Gis-Based Landslide Susceptibility Mapping Using Logistic Regression, Instability Index, And Support Vector Machine: Case Study Of The Jingshan River, Taiwan, Hsun-Chuan Chan, Yu-Chin Chen, Jung-Tai Lee, Yu-Ting Wen

Journal of Marine Science and Technology–Taiwan

Many techniques have been developed to produce landslide susceptibility maps. However, mapping the spatial distribution of landslide susceptibility involves critical steps. This study evaluated susceptibility to the occurrence of shallow landslides in upstream areas of the Jingshan River, Taiwan, where heavy rainfall has resulted in increased landslide occurrence and reservoir sedimentation. The landslide susceptibility case study was conducted using logistic regression, an instability index method, and support vector machine (SVM). A selection procedure was first developed to identify the factors influencing landslide occurrence. Historical landslide data were used to assess the corresponding parameters of each model. The receiver operating characteristic …


Sea Ice Warning Visualization And Path Planning For Ice Navigation Based On Radar Image Recognition, Tsung-Hsuan Hsieh, Shengzheng Wang, Huijia Gong, Wei Liu, Ning Xu Jul 2021

Sea Ice Warning Visualization And Path Planning For Ice Navigation Based On Radar Image Recognition, Tsung-Hsuan Hsieh, Shengzheng Wang, Huijia Gong, Wei Liu, Ning Xu

Journal of Marine Science and Technology–Taiwan

Ice navigation is currently one of the important issues in path planning studies. Most studies are using sea ice models or ice charts for large-scale path planning, but the weather and ice conditions in the polar waters usually change quickly and are not easy to predict. Under these conditions, small-scale path planning that can be adjusted in time for sea ice collision avoidance is needed. This study uses marine radar imaging to reconstruct the ice navigation scene, and establishes a visual-ization function of sea ice warning on the radar image. We combine the bidirectional rapidly-exploring random tree (B-RRT) algorithm and …


Enhancing Marine Administrative Management Based On Human Factor Through Safety Criteria, Wen-Cheng Lin, Hsin-Hung Cheng Jul 2021

Enhancing Marine Administrative Management Based On Human Factor Through Safety Criteria, Wen-Cheng Lin, Hsin-Hung Cheng

Journal of Marine Science and Technology–Taiwan

This study aims to improve maritime safety by enhancing administrative management based on human factors. This study used Fuzzy analytic hierarchy process to analyze the risks and threats regarding safety maritime criteria. Establishing administrative reform is given the highest priority. First, the current model for crew training system is explored. Second, the marine surveyor is examined to determine if it is professional enough for inspection work. Third, the investigation system used by maritime safety investigators should be inspected. The suggestions mentioned expect to establish a maritime administrative reform that could pave the way for the application of maritime safety around …


A Dea Approach Towards To The Evaluation Of Iot Applications In Intelligent Ports, Guo-Ya Gan, Hsuan-Shih Lee, Jia-Yi Liu Jul 2021

A Dea Approach Towards To The Evaluation Of Iot Applications In Intelligent Ports, Guo-Ya Gan, Hsuan-Shih Lee, Jia-Yi Liu

Journal of Marine Science and Technology–Taiwan

No abstract provided.


Experimental Study On Treatment Of Ballast Water By Inert Flue Gas Deoxidation, Guozhi Bao, Peng Yang, Rui Da, Junxia Li, Guanghui Zhao, Ning Chen Jul 2021

Experimental Study On Treatment Of Ballast Water By Inert Flue Gas Deoxidation, Guozhi Bao, Peng Yang, Rui Da, Junxia Li, Guanghui Zhao, Ning Chen

Journal of Marine Science and Technology–Taiwan

In this paper, the antimicrobial effect of inert flue gas on indicator microorganisms in ballast water was investigated based on a 265h test. The inert flue gas consists of nitrogen (N2) and carbon dioxide (CO2) the microorganisms include Chlorella and Escherichia coli. Within the scope of the test, the killing effect of the microbes treated by combining N2 and CO2 was higher than that of using only either N2 or CO2. When the dissolved oxygen concentration in the ballast water was 0.5 mg/L and the pH value was 6, the killing effect was the highest. At this time, the mortality …


Simulation Of Light Propagation Captured By Photoemission Electron Microscopy (Peem), Nabila Islam Jul 2021

Simulation Of Light Propagation Captured By Photoemission Electron Microscopy (Peem), Nabila Islam

Dissertations and Theses

The Photoemission electron microscopes (PEEM) is a powerful tool capable of synchronously imaging wave nature of light manifested by interference patterns as well as its particle nature through the energy exchange between the incident photons and the photoemitted imaging electrons. PEEM offers a non-invasive high-resolution approach for studying light propagation and interaction phenomena within a nanophotonic waveguide [7,8]. The electric field intensity variation of the interference pattern yielded by the interaction between the incident light and the guided mode coupled into the waveguide produces varying photoemission yields creating contrast in PEEM image. The guided modes cannot be excited simply by …


Mechanical Properties And Microstructure Characteristics Of Alloy Parts Produced By Laser Powder Bed Fusion (Lpbf) Method, Hong Yao Jul 2021

Mechanical Properties And Microstructure Characteristics Of Alloy Parts Produced By Laser Powder Bed Fusion (Lpbf) Method, Hong Yao

LSU Doctoral Dissertations

Additive manufacturing (AM) is a rapid prototyping technology to produce fully functional and complex designing objects. As one of the AM methods, Laser Powder Bed Fusion (LPBF) has gained the most attention from both academic researchers and industrial companies. During the LPBF process, metal powders are applied layer by layer, which can be 20 microns to 50 microns in thickness. After a layer is prepared, a high-power laser, which is commonly controlled by a scanning head, is used to selectively melt the interested area of a 2D geometry which is designed in a computer aided designing software. LPBF method can …


Structural Vibration Control Of Offshore Wind Turbines, Vahid Jahangiri Jul 2021

Structural Vibration Control Of Offshore Wind Turbines, Vahid Jahangiri

LSU Doctoral Dissertations

Offshore wind turbines (OWTs) are becoming more attractive than their onshore counterparts due to advantages such as high wind speed, less visual impact and less noise constraints in the marine area. However, the combined wind, wave and seismic loading and other environmental effects render the offshore wind turbines suffering from excessive vibration which adversely influences the system performance and structural integrity. In this regard, the present dissertation aims to develop effective structural control techniques to mitigate three-dimensional structural vibrations of offshore wind turbines. Analytical models of a fixed-bottom and floating offshore wind turbine are established using Euler-Lagrangian equation wherein the …


Advanced Methods For Steady-State And Stability Analyses Of Hybrid Power Systems, Mohammad Mehdi Rezvani Jul 2021

Advanced Methods For Steady-State And Stability Analyses Of Hybrid Power Systems, Mohammad Mehdi Rezvani

LSU Doctoral Dissertations

The term hybrid power grids refer to the combination of two power systems with different intrinsic characteristic. For instance, ac-dc grids and transmission-distribution systems are kinds of hybrid power grids. Challenges in analyzing the hybrid power grids arise since two sets of equations should be solved either simultaneously or sequentially. In the simultaneous (unified) methods, the ac and dc system of equations are solved simultaneously, while, in the sequential approaches, these equations are solved in an error loop. In this dissertation, a unified method is proposed for steady-state and fault analyses of hybrid ac-dc power grids, while a sequential approach …