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"The increase of fuel price has caused fleet operational and shipping business to be in danger situation. The fuel consumption of a ship is influenced by ship volume or wetted area which contributes directly to the increase of ship resistance and the size of main engine. In order to find out the appropriate answers, a series of investigation into river transportation using monohull, catamaran and trimaran types of vessel was carried out. The work focused on theestimation of total resistance and powering as well as seakeeping characteristics and carried out experimentally using tank test and numerically using a ship design software (Maxsurf). It was found out that the catamaran and trimaran could have less resistance and hence power compared to monohull of similar displacement. The seakeepingcharacteristics of the multihull vessels were also comparable with those of the monohull. This is a good indication that river catamaran/trimaran is an efficient and comfortable vessel. If a prototype or real vessel is developed, it can be a very efficient ship as well as a ship with high safety standard."

"Resistance or drag is one of the most important factors in ship design, in particular in connection with the development of more efficient and environmentally friendly vessels. The shape of the hull under water will affect the fluid flow characteristics around the ship, hence causing the resistance to increase or decrease. If the resistance increases, the size of main engine and subsequently, the fuel consumption increases accordingly and this is not often anticipated by ship designers and operators. The use of a catamaran for passenger carriers is well known and its application for fishing vessels has received serious attention in the last few years, due to its advantages to produce wider deck area and smaller size of engine at the same displacement as the monohulls. The conversion of monohull fishing vessels in Cilacap the waters into a catamaran hull is an interesting topic in association with the development of better fishing vessels in this region. The resistance investigation of the conversion vessel was carried out by Computational Fluid Dynamics (CFD) approach and this is combined with classical slender body theory. In terms of mathematical calculation, the results between CFD and the combination of empirical formulas and slender body theory shows such a good agreement and the difference between the two is less than 5%. In terms of naval architecture, the results showed that the modification of a monohull vessel into a catamaran can increase the payload capacity up to two times. Conversely, this causes the resistance to increase about almost four times and this is certainly unpopular for the fishermen."

"Indonesia merupakan negara dengan gugusan pulau terbanyak di dunia dengan lebih dari 17.000 pulau. Hal tersebut menjadi tantangan tersendiri bagi pemerintah dalam pemerataan fasilitas pelayanan kesehatan di tiap daerah Indonesia. Berdasarkan data dari Perhimpunan Rumah Sakit Seluruh Indonesia (PERSI) tahun 2020 terdapat 2.924 unit rumah sakit yang terdiri dari 60 rumah sakit kelas A, 430 rumah sakit kelas B, 1.524 rumah sakit kelas C, 42 rumah sakit kelas D pratama, dan 52 rumah sakit lainnya yang belum dikategorikan. Persebaran rumah sakit di Indonesia masih belum merata. Hal tersebut dibuktikan dengan data peta persebaran rumah sakit yang masih terpusat di pulau Jawa dan sebagian pulau Sumatera sedangkan daerah bagian timur Indonesia masih sangat minim fasilitas rumah sakit. Salah satu fasilitas pelayanan kesehatan yang cocok dengan kondisi geografis Indonesia yaitu kapal ambulans. Agar kapal ambulans dapat melakukan tugasnya dengan baik maka kapal tersebut harus memiliki performa yang baik dari segi teknisnya. Salah satu faktor yang mempengaruhi performa kapal yaitu bentuk lambung. Tujuan dari tugas akhir ini yaitu menganalisis pengaruh bentuk lambung terhadap performa kapal ambulans. Variabel bentuk lambung yang digunakan dalam penelitian ini yaitu monohull, katamaran, dan semi trimaran pelat datar. Batasan penelitian untuk performa kapal yaitu terkait dengan hambatan, stabilitas, dan olah gerak kapal. Dari hasil penelitian diperoleh hambatan total terbesar yaitu lambung semi trimaran pelat datar dengan total hambatan 90,9 kilonewton. Diikuti oleh monohull dengan hambatan total sebesar 73,8 kilonewton dan katamaran dengan hambatan total sebesar 59,3 kilonewton. Pada perhitungan stabilitas kondisi muatan penuh model lambung katamaran memiliki nilai lengan pembalik (GZ) maksimum tertinggi yaitu sebesar 2,353 meter pada sudut 20,9 derajat. Semi trimaran memiliki nilai GZ maksimum tertinggi kedua yaitu sebesar 1,472 meter pada sudut 45,5 derajat. Terakhir yaitu monohull yang memiliki nilai GZ maksimum sebesar 1,164 meter pada 40 derajat. Pada perhitungan olah gerak kapal dilakukan pada sudut datang gelombang 0°, 45°, 90°, dan 180° dengan tiga derajat kebebasan (heave, roll, dan pitch). Nilai perpindahan gerakan heaving kapal terbesar dialami oleh model lambung katamaran dengan nilai perpindahan 0,54 meter pada sudut datang gelombang 180 derajat. Nilai rotasi gerakan rolling kapal terbesar dialami oleh model lambung semi trimaran dengan nilai rotasi 8,07 derajat pada sudut datang gelombang 90 derajat. Nilai rotasi gerakan pitching kapal terbesar dialami oleh model lambung monohull dengan nilai rotasi 3,89 derajat pada sudut datang gelombang 0 derajat.

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Indonesia is a country with the most islands in the world with more than 17,000 islands. This is a challenge for the government in distributing health care facilities in each region of Indonesia. Based on data from Perhimpunan Rumah Sakit Seluruh Indonesia (PERSI) in 2020 there were 2,924 hospital units consisting of 60 class A hospitals, 430 class B hospitals, 1,524 class C hospitals, 42 class D hospitals, and other 52 hospitals that have not been categorized. The hospitals in Indonesia is still not evenly distributed. This is evidenced by the map data of the distribution of hospitals which are still centered on the island of Java and Sumatra, while the eastern region of Indonesia is few hospital facilities. One of the health care facilities that suitable with the geographical conditions of Indonesia is an ambulance ship. In order for the ambulance ship to do its job well, the ship must have good performance from a technical point of view. One of the factors that affect the performance of the ship is the form of the hull. The objective of this thesis is to analyze the effect of the hull form on performance of ambulance ship. Hull form variables that used in this study were monohull, catamaran, and flat plate semi trimaran. Research limitations for ship performance are related to drag, stability, and seakeeping. From the results of the study, the largest total resistance was the flat plate semi trimaran hull with a total resistance of 90.9 kilonewtons. Followed by the monohull with a total resistance of 73.8 kilonewtons and the catamaran with a total resistance of 59.3 kilonewtons. In the calculation of the stability of the full load condition, the catamaran hull model has the highest maximum righting arm (GZ) value of 2,353 meters at an angle of 20.9 degrees. Semi trimaran has the second highest maximum GZ value of 1,472 meters at an angle of 45.5 degrees. Finally, the monohull has a maximum GZ value of 1,164 meters at 40 degrees. The calculation of ship motion is carried out at the heading angles of 0°, 45°, 90°, and 180° with three degrees of freedom (heave, roll, and pitch). The largest ship heaving displacement value is experienced by the catamaran hull model of 0.54 meters displacement at 180 degrees heading angle. The largest rotational value of the ship's rolling motion is experienced by the semi-trimaran hull model with a rotation value of 8.07 degrees at heading angle of 90 degrees. The largest ship pitching motion rotation value is experienced by the monohull hull model with a rotation value of 3.89 degrees at heading angle of 0 degrees."

"Usaha para peneliti untuk menciptakan alat transportasi air (kapal) yang hemat energi terus dilakukan hingga saat ini. Modifikasi geometri, dimensi dan jumlah lambung merupakan suatu hal yang penting dalam usaha pengurangan hambatan kapal. Penggunaan Jenis kapal berlambung banyak katamaran dan trimaran mencapai angka 40% dari total kapal yang berlayar. Hambatan total kapal terdiri atas hambatan gesek dan hambatan sisa. Hambatan gesek merupakan fungsi dari geometris, perubahan tekanan, kekasaran permukaan dan coating pada permukaan lambung. Hambatan sisa fungsi dari gaya seret gelombang yang terbentuk oleh masing-masing lambung kapal. Dengan kemajuan ilmu material, diciptakan berbagai macam cat yang dapat berfungsi sebagai pelindung dinding kapal dan sebagai pengurang koefisien gesek. Kulit ikan belut yang mengandung lendir merupakan biopolimer yang ramah lingkungan dan tidak beracun. Tujuan dari penelitian ini yaitu mengetahui efek variasi pelekatan biopolimer kulit belut (Monopterus Albus) pada lambung model kapal monohull, katamaran asimetris dan trimaran asimetris terhadap hambatan total model kapal dengan variasi bilangan Froude. Model kapal monohull, katamaran dan trimaran dengan pendekatan displacement yang sama dan diberikan variasi posisi pelekatan kulit belut pada lambung model kapal ditarik dengan variasi kecepatan pada kolam percobaan. Variasi sarat dan trim digunakan pada percobaan ini. Pengukuran tegangan tali pada kecepatan kapal konstan (tercapainya terminal velocity) dilakukan dengan load cell transducer yang terhubung ke data akusisi. Percobaan dilakukan dengan teliti dan dilakukan pengulangan secepat mungkin untuk menghindari degradasi biopolimer lendir belut. Percobaan dilakukan pada air tawar dan perubahan temperatur seminimal mungkin (dijaga konstan). Hasil menunjukkan pelekatan biopolimer pada monohull menghasilkan drag reduction sebesar 8 % pada bilangan Re = 20.000. Pada kapal katamaran asimetris, S/L = 0,2 terjadi drag reduction sebesar 6 % pada bilangan Froude = 0,45. Pada kapal trimaran asimetris, S/L = 0,2 dan R/L = 0,0 terjadi drag reduction sebesar 10.4 % pada bilangan Froude = 0,35. Dimungkinkan efek biopolymer mempengaruhi distribusi kecepatan pada lapisan terluar (outer layer) sehingga laju kecepatan kapal bertambah.

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Up to present time researchers are still continuously attempting to create energy saving water transportation vehicles (ships). Geometry, dimensions and number of hulls modification is an important effort to reduce the resistance of ship. The use of multi-hull ships such as catamaran and trimaran has reached 40% of total sailing ships. Total ship resistance consists of frictional resistance and residual resistance. Frictional resistance is the function of geometrics, pressure changes, surface roughness and coating of the hull surface. Residual resistance is the function of wave dragging force created by individual hull. With the advancement of material science various kind of paints have been created that could act as hull protection and as frictional coefficient reducer. Eel skin contents mucus that is environmentally friendly and non-toxic.

The objective of the research is to investigate the effects of Monopterus Albus biopolymer attachment variations on monohull, asymmetric catamaran, and asymmetric trimaran model hulls to ship model total resistance with variation of Froude numbers. Monohull, catamaran, and trimaran ship models with same displacement approach were attached with eel skin at various positions on their hulls, the ship models were towed with various speeds on the test basin. Variation of drafts and trims were applied on the experiment. The tensions of the towing string at constant ship speed (at the terminal velocity) were measured using load cell transducer which was connected to data acquisition. The experiment was conducted very carefully and repetitions were carried out very quickly in order to avoid the degradation of Monopterus Albus biopolymer. The experiment was carried out on fresh water with very little changes of temperatures (kept constant).

The results showed the attachment of biopolymer on monohull produced 8% of drag reduction at Re number = 20.000. On asymmetric catamaran with S/L = 0.2 produced 6% drag reduction at Fr = 0.45. On asymmetric trimaran with S/L = 0.2, and R/L = 0.0 produced 10.4% drag reduction at Fr = 0.35. These results are due to the effect of biopolymer in distributing the velocity at the outer layers that increase the velocity of the ships."

"This project is motivated from environmental degradation and pollution problems caused by the outboard motors. Environmental and safety constraints are an increasingly necessity which enforces the demand for new technologies and development. Therefore, this research aims to provide velocity field data correlated to water quality measurements taken during the field tests and used to establish the effect from the outboard motor. Acoustic Doppler Velocimeter (ADV) is widely used for field measurement of two and three dimensional water velocity. The implementation of the ADV measurement technique is accomplished by measuring the phase change in the acoustic signal reflected of the scattering particles in the flow, than by looking at the data that the ADV gave I?ll be using a lot of statistical method in order to identify the outboard velocity signature, the are 9 statistical method that I?m going to use which is: One second average of mean velocity One second average of standard deviation One second average of resultant velocity One second average of skewness One second average of kurtosis One second average of angle of resultant velocity make with x axis Wavelet FFT One second average of Backscatter Intensity (BSI) After using all of the statistical analysis mention above, than I will identify the best statistical method in order to identify the outboard velocity signature. Further analysis will be done by looking at the changing value of mean velocity and backscatter intensity, this than will help to identify the behaviour of different types of outboard motor that used in this research."

"Palu City is an active seismic area in Indonesia due to the very active Palu-Koro fault system. The development of the city area, therefore, must consider the risks induced by the seismic activities. The risk assessment has to be supported by information on subsurface characteristics. The aim of this study is to investigate the characteristics of the subsurface of the area by considering the value of Vs30 (top 30 m shear-wave velocity). This parameter has been related to the estimation of the site’s ground shaking during the occurrence of an earthquake. The measurements taken in the deep soil sediment include the microtremor array, using the spatial auto correlations (SPAC) method, as well as the site’s dominant period measurement, using the horizontal-to-vertical spectral ratio (HVSR) method. All these parameters were local site parameters, which could be subsequently related to a description of the potential impact in an area near to the epicenter. The measurement of Vs30 was conducted in collaboration between the Indonesian Agency for Meteorology, Climatology, and Geophysics (Badan Meteorologi, Klimatologi, dan Geofisika) (BMKG) and the University of Indonesia (Universitas Indonesia) (UI); the overall surveys included Vs30 measurements at 44 sites, microtremor array surveys at 10 sites, and the dominant period measurements at 74 sites. The overall results indicated that there is a good correlation between Vs30 and the dominant period. In general, Palu City is predominantly a class-D site, but the northwest part of the Palu area is a class-C site."

"Increasing energy demand, in line with the rate of population growth, is always followed by the pace of the waste dump. Where the largest percentage comes from organic waste, it is potentially utilized as raw material of biomass mixture for emission reduction efforts in fuel conversion from waste energy. The main objective of this paper is to study the characteristics of co-gasification, especially gasification temperature, lower heating value and gas emission, on the performance of the biomass gasification process in a downdraft fixed bed gasifier. In this study, organic waste used twigs, coconut fibers and rice husks in the pelletization as raw materials on the combustion technology Downdraft Gasifier. Methods were carried out by co-gasification techniques between WCF (wood-coconut fibers) pellet and rice husk on 100% pellet composition, 75:25, 50:50, 25:75 and 100% rice husk. Syngas testing is done with direct measurement on the burner with TCD type Shimadzu 8A gas chromatography. The highest reactor temperature in the pyrolysis zone was 400oC to 850oC and the temperature in the oxidation zone was 1000oC to 1200oC. The result of the synthetic gas testing obtained the highest lower heating value (LHV) in WCF 100% pellet composition at 4.07 MJ/Nm3 with 85% efficiency. The lower heating value of the lowest syngas in a 100% pellet composition was 2.99 MJ/Nm3, where the increase of WCF pellets will increase the LHV syngas value. This resulted in visually low tar content and low ash particles in all compositions of approximately 30 to 35% of the initial mass of each composition, with the lowest ash in 100% rice husk composition at 0.29 g."

"Karakteristik fisik wilayah dapat memengaruhi pengikisan tanah dalam jumlah yang besar yang sering disebut dengan longsor. DA Ci Sangu merupakan salah satu sungai yang sering mengalami pengikisan tanah pada tebing sungai akibat banjir. Apabila pengikisan tebing sungai ini berlangsung terus menerus, dikhawatirkan akan terjadi longsoran yang lebih besar lagi pada tebing sungai. Penelitian ini bertujuan untuk menganalisis potensi longsor yang terjadi sepanjang aliran Ci Sangu dan menganalisis keterkaitan antara potensi longsor tebing sungai dengan karakteristik fisik wilayah. Pada penelitian ini penentuan potensi longsor akan menggunakan Metode Indeks Storie, sedangkan karakteristik fisik tebing sungai akan diobservasi secara langsung pada 33 sampel lokasi. Variabel penelitian ini terdiri atas penggunaan lahan, kemiringan lereng, bentuk lereng, jenis tanah dan curah hujan. Analisis dilakukan menggunakan analisis spasial. Didapat hasil bahwa semakin menuju ke arah hilir, tebing sungai lebih banyak mengalami pengikisan yang sedang dan berat. Potensi longsor tebing sungai yang tinggi dan sedang banyak dijumpai pada tebing sungai yang memiliki kemiringan yang terjal dengan kemiringan >45%. Jenis tanah yang mendominasi pada wilayah tersebut adalah Asosiasi Podsolik Kuning dan Hidromorf Kelabu dengan curah hujan 2000-2500 mm/tahun dan penggunaan lahan dominan pada wilayah tersebut adalah sawah.

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The physical characteristics of the area can affect large amounts of soil erosion, often called landslides. DA Ci Sangu is one of the rivers that often experiences soil erosion on river banks due to flooding. When river bank erosion continues, it is feared that there will be even more landslides on the river bank. This study analyzes the potential for landslides that occur along the Ci Sangu flow and analyzes the relationship between river bank landslide potential and the physical characteristics of the area. In this study determining the potential for landslides will use the Storie Index Method, while the physical characteristics of river banks will be directly observed in 33 sample locations. The variables of this study consisted of land use, slope, slope shape, soil type and rainfall. The analysis was carried out using spatial analysis. Obtained results downstream, more river cliffs increase moderate and heavy erosion. Potential river bank landslides are high and are being found on river banks that have slopes that are run with slopes> 45%. The types of soil that support the area are yellow podsolik and gray hydromorph with rainfall 2000-2500 mm / year and the dominant land use in the area is paddy fields."

"Sungai Ciliwung merupakan sumber air bersih untuk wilayah sekitarnya, akan tetapi, ditemukan mikroplastik yang berbahaya bagi lingkungan dan kesehatan pada air sungai alirannya berasal dari saluran input. Penelitian ini bertujuan untuk menganalisis kelimpahan mikroplastik, karakteristik mikroplastik berdasarkan jenis, material, dan warna, serta pengaruh waktu terhadap kelimpahan partikel mikroplastik di aliran input Sungai Ciliwung. Untuk menganalisis kelimpahan dan karakteristik mikroplastik, digunakan metode metode National Oceanic and Atmosphere Administration (NOAA) dan FTIR. Sedangkan, untuk menguji pengaruh waktu terhadap kelimpahan mikroplastik, dilakukan analisis t-test dependent (paired). Hasil penelitian menunjukkan bahwa kelimpahan mikroplastik di aliran input Sungai Ciliwung bernilai antara 668—1918 partikel/liter dengan rata-rata 1273,64 partikel/liter dan jumlah yang fluktuatif di setiap titik pengambilan sampel. Bentuk yang ditemukan pada partikel mikroplastik adalah 93% fragment, serta fiber, microbeads, film, dan foam dalam jumlah kecil. Warna yang ditemukan adalah 37% transparan, 32% merah, 23% hitam, serta biru, hijau, dan kuning dalam jumlah sedikit. Dari hasil uji material, ditemukan polimer, Polyvinyl formal (PVFM), Poly vinylchloride (PVC), PVC Film (PVC-DR), dan Soft PVC (PVC2). Waktu berpengaruh pada kelimpahan mikroplastik dalam rentang musim serta hari kerja dan akhir pekan. 

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The Ciliwung River is a source of clean water for the surrounding area; however, microplastics that are harmful to the environment and health are found in the river water, which flows from the input channel. This research aims to analyze the abundance of microplastics, the characteristics of microplastics based on type, material, and color, as well as the effect of time on the abundance of microplastic particles in the Ciliwung River input stream. The National Oceanic and Atmosphere Administration (NOAA) and FTIR methods were used to analyze the abundance and characteristics of microplastics. Meanwhile, to test the effect of time on the abundance of microplastics, a t-test-dependent (paired) analysis was performed. The results showed that the abundance of microplastics in the input stream of the Ciliwung River was between 668-1918 particles/liter, with an average of 1273.64 particles/liter and the amount fluctuated at each sampling point. The form found in microplastic particles is 93% fragments and small amounts of fibers, microbeads, films, and foam. The colors were 37% transparent, 32% red, 23% black, and small amounts of blue, green, and yellow. From the results of the material test, Tencel, Polyvinyl formal (PVFM), Polyvinylchloride (PVC), PVC Film (PVC-DR), and Soft PVC (PVC2) were found. Timing influences the abundance of microplastics over a range of seasons, as well as weekdays and weekends."

"[Sarana angkutan laut yang popular untuk transportasi utama yaitu kapal.Kapal Eretan Muara Gembong adalah kapal penyeberangan pada perairan sungaiyang menghubungkan Kabupaten Bekasi dengan Kabupaten Karawang. Padapenelitian ini untuk bisa mendapatkan perancangan atau desain kapal yangmemenuhi persyaratan keamanan dan keselamatan penumpang dilihat dari aspekstabilitas sesuai aturan yang berlaku yaitu standar dan memenuhi kriteriakeselamatan IMO guna mendapat izin kapal beroperasi. Perhitungan stabilitasyang dilakukan berupa proses pengujian kemiringan kapal (inclining test) berbasisIACS Standard. Dengan berkembangnya teknologi maka untuk mengetahui danmenghitung stabilitas kapal ini menggunakan Software HidromaxPro untuk lebihakurat hasilnya dan juga akan diperhatikan hasil pengujian apakah hasil pengujiantersebut dengan permodelan dan perhitungan dengan Software HidromaxPromemenuhi kriteria keselamatan IMO., A popular means of sea transport for the main transportation is ship.Eretan Muara Gembong boat is a ship crossing the waters of the river thatconnects the Bekasi regency of Karawang Regency. In this research to be able toget a ship design that meets the requirements of security and passenger safetyfrom the aspects of stability according to the rules, namely the safety of IMOstandards and criteria in order to obtain permission to operate the vessel. Stabilitycalculations are carried out in the form of tilt testing process vessel (inclining test)based IACS Standard. With the development of the technology to determine andcalculate the stability of the ship using Software HidromaxPro for more accurateresults and also will be considered the results of testing whether the test resultswith the modeling and calculations with Software HidromaxPro IMO safetycriteria.]"