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"Perceived opportunities for increased local power and control of resources in the early euphoria of post-Soeharto decentralization saw no less than four new province proposals within the present boundaries of South Sulawesi. Two of those developed into formal submissions which, at the time of writing, are being considered by the national government. These are for new provinces of West Sulawesi and Greater Luwu, which would encompass approximately fifty-five per cent of South Sulawesi's present land mass. This article discusses those movements and the rationale behind their emergence. Residents in each region express dissatisfaction at long-term neglect by the South Sulawesi government. In particular, kabupatens calling for the establishment of West Sulawesi have been ignored in the development process. Following calls for the new province, the South Sulawesi leadership has promised increased recognition of the western regions. West Sulawesi and Luwu Raya are viewed as possessing high potential for resource development, particularly in plantation agriculture, fisheries, and mineral exploration. Ethnic identity has also been a factor in the new province demands. In some cases, preexisting ethnic tensions have been exacerbated by debates centered upon proposed province boundaries. Calls for change should be seen as a sign of dissatisfaction with the South Sulawesi leadership rather than with national governance, as new structures would by-pass present provincial authority, strengthening ties with the centre by allowing direct interaction between the respective regions and Jakarta."

"Pengaruh doping Cu pada material La0,5Ca0,5Mn1-xCuxO3 telah dikaji dengan variasi konsentrasi doping x=0,05; 0,15; dan 0,20. Pada setiap doping menunjukkan temperatur Curie, TC, di atas 225 K dan temperatur Neel (charge order), TCO, sedikit di bawah 150 K dan tidak terjadi perbedaan untuk masingmasing doping. Hasil pengukuran magnetisasi material terhadap medan magnet luar pada temperatur rendah (di bawah TCO) menunjukkan pemisahan kurva yang semakin jelas. Pemisahan ini menunjukkan lebih dari satu fasa muncul secara bersama-sama (koeksistensi) yang berkorelasi dengan meningkatnya fraksi charge ordered-antiferromagnetic (CO-AFM) dan menurunnya fraksi ferromagnetik (FM).

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The influence of Cu doping in La0,5Ca0,5Mn1-xCuxO3 has been reported by different concentration of doping x=0,05; 0,15; and 0,20. Each of doping samples hows that Curie temperature, TC, above 225 K and Neel temperature (charge order), TCO, below 150 K and does not show any difference for each doping. Result of magnetization measurement by external magnetic field at low temperature (below TCO) shows the appearance of curve separation clearly. Such separation indicates that coexistence of more than one phase correlated with the increase of fraction of charge ordered antiferromagnetic (CO-AFM) and the decrease of ferromagnetic (FM) fraction."

"Pengembangan lapangan gas bumi baru setelah ditemukan memerlukan desain pabrik pengolahan gas bumi, termasuk di Lapangan X. Selain desain proses, desain kontrol proses juga sangat penting. Untuk itu, pada pemisahan awal gas bumi yang akan diproses lebih lanjut, dirancang pengendalian proses menggunakan pengontrol proporsional-integral berbasis sistem identifikasi ulang (PI-SRI). Terdapat tiga sumur (Alpha, Betha, dan Charlie), separator dan cooler pada proses pemisahan awal dan terdapat tiga jenis kontroler (tekanan [PC], level [LC] dan temperatur [TC]). Untuk menentukan parameter kontroler PI yang optimal, dilakukan tiga kali identifikasi sistem untuk menghasilkan tiga model first-order plus dead-time (FOPDT). Ketiga model tersebut dimasukkan dalam persamaan tuning untuk metode Ziegler-Nichlos sehingga dihasilkan tiga parameter kontroler PI. Untuk menguji kinerja kendali yang optimal digunakan perubahan set point (SP) pada PC, LC dan TC, serta gangguan berupa perubahan laju aliran gas bumi yang berasal dari ketiga sumur tersebut. Indikator kinerja pengendalian yang digunakan adalah overshoot dan settling time. Hasil penelitian menunjukkan bahwa model FOPDT untuk proses pemisahan awal produksi gas bumi berdasarkan tiga variabel terkontrol memiliki =−1,614, =0,24 dan =0,01 untuk PC; =−0.882, =0.2295 dan =0.2385 untuk LC dan =−0.063, =1.5075 dan =0.0425 untuk TC. Harga parameter kontroler PI yang memberikan performansi kontrol optimum (overshoot dan settling time) adalah =−13,383, =0,033 untuk PC; =−132.6, =0.483 untuk LC, dan =−506.7, =0.142 untuk TC.

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The development of a new natural gas field after being discovered requires the design of a natural gas processing plant, including in Field X. In addition to process design, process control design is also very important. For this reason, at the initial separation of natural gas which will be further processed, process control is designed using a proportional-integral controller based on a re-identification system (PI-SRI). There are three wells (Alpha, Betha, and Charlie), separator and cooler in the initial separation process and there are three types of controllers (pressure [PC], level [LC] and temperature [TC]). To determine the optimal PI controller parameters, three system identifications were carried out to produce three first-order plus dead-time (FOPDT) models. The three models are included in the tuning equation for the Ziegler-Nichlos method so that three PI controller parameters are produced. To test the optimal control performance, changes in the set point (SP) of the PC, LC and TC are used, as well as disturbances in the form of changes in the flow rate of natural gas originating from the three wells. The control performance indicators used are overshoot and settling time. The results showed that the FOPDT model for the initial separation process of natural gas production based on three controlled variables had =−1.614, =0.24 and =0.01 for PC; =−0.882, =0.2295 and =0.2385 for LC and =−0.063, =1.5075 and =0.0425 for TC. The parameter values ​​for the PI controller that provide optimum control performance (overshoot and settling time) are =−13,383, =0.033 for PC; =−132.6, =0.483 for LC, and =−506.7, =0.142 for TC."

"Separasi vertikal merupakan salah satu langkah yang dapat diambil untuk menciptakan persaingan usaha yang sehat dalam sektor perkeretaapian. Penelitian ini bertujuan untuk meninjau secara yuridis terkait implementasi separasi vertikal layanan perkeretaapian di Indonesia dan Inggris, serta mengevaluasi apa yang dapat diambil dari kasus perkeretaapian di Inggris untuk diterapkan di Indonesia. Penelitian ini menemukan bahwa di Inggris, separasi vertikal sudah diterapkan secara institusional untuk menciptakan kompetisi dalam sektor perkeretaapian. Sementara itu, di Indonesia, meskipun telah meninggalkan kompetisi monopoli tunggal melalui UU 23 Tahun 2007, persaingan masih belum optimal. Masih banyak hal yang perlu diperkenalkan terutama pemisahan vertikal sebagai prekursor dari kompetisi, derajat kompetisi, dan peran swasta. Oleh karena itu, untuk mengetahui dan belajar dari kasus perkeretaapian di Inggris, penelitian ini menyarankan agar Indonesia dapat memperhatikan apa yang dapat diambil dari kasus tersebut untuk dijadikan implementasi di Indonesia. penelitian ini juga membahas Indonesia meningkatkan kompetisi dan mengakomodirnya melalui mekanisme tender, penunjukan langsung, dan penugasan, sementara Inggris memiliki badan regulator kereta api yang merupakan perpanjangan tangan dari pemerintah untuk mengatur kompetisi yang sehat diantara perusahaan operator kereta api. Kedua negara juga memiliki perbedaan dalam pengaturan terkait dengan peran swasta dalam sektor perkeretaapian, dengan Indonesia masih belum optimal dalam mengakomodir peran swasta, sedangkan Inggris telah memberikan peran aktif kepada swasta.

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Vertical separation is one step that can be taken to create healthy competition in the railway sector. This research aims to review the legal aspects of the implementation of vertical separation of railway services in Indonesia and United Kingdom, and to evaluate what can be taken from the railway case in United Kingdom to be applied in Indonesia. This research found that in United Kingdom, vertical separation has been institutionally applied to create competition in the railway sector. Meanwhile, in Indonesia, although it has left a single monopoly competition through Law No. 23 of 2007, competition is still not optimal. There are still many things that need to be introduced, especially vertical separation as a precursor to competition, the degree of competition, and the role of the private sector. Therefore, to learn from the railway case in United Kingdom, this research suggests that Indonesia can pay attention to what can be taken from the case for implementation in Indonesia. This research also discusses how Indonesia can increase competition and accommodate it through tendering mechanisms, direct appointments, and assignments, while United Kingdom has a railway regulatory body that is an extension of the government to regulate healthy competition among railway operators. Both countries also have differences in regulations regarding the role of the private sector in the railway sector, with Indonesia still not optimal in accommodating private sector participation, while United Kingdom has given an active role to the private sector."

"Kebutuhan pelumas terus meningkat Namun saat ini ketersediaan minyak bumi semakin menipis karena kebutuhan yang terus meningkat. Selain itu, pelumas berbahan dasar minyak bumi memiliki pengaruh negatif terhadap lingkungan karena memiliki sifat yang negatif diantaranya adalah non-renewable, tidak ramah lingkungan dan beracun. Pelumas sintetis merupakan bahan kimia dengan karakteristik lebih baik dibandingkan pelumas mineral dan nabati. Pelumas sintetik terbentuk dari senyawa kimia dengan spesifikasi berkualitas dan dirancang melalui proses sintetik untuk mendapatkan pelumas dengan karakteristik yang spesifik dan sesuai yang diinginkan. Sintesis Pelumas Berbasis Ester dapat dilakukan dengan proses oligomerisasi, esterifikasi dan separasi. Penelitian ini akan menjelaskan mengenai sistem pengendalian proses separasi pada perancangan pabrik Pelumas Berbasis Ester untuk menjaga kestabilan proses produksi pada sebuah pabrik. Pada penelitian ini proses yang akan dikendalikan adalah proses separasi asam n-heptanoat untuk mendaur ulang zat antara yang digunakan untuk memproduksi senyawa Pelumas Berbasis Ester. Pengendalian yang digunakan adalah pengendalian Proporsional Integral (PI) dengan menggunakan metode Ziegler Nichols, Lopez dan Autotuner. Parameter kinerja pengendali yang diperhitungkan menggunakan metode IAE (Integral Absolute Error), ISE (Integral Squared Error) dan ITAE. (Integral of Time Multiplied by Absolute Error). Pada penelitian ini penyetelan pengendalian optimum dicapai dengan menggunakan metode Autotuner dan root mean squared (RMS) terendah didapatkan dengan metode Solver.

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The need for lubricants continues to increase. However, currently the availability of petroleum is dwindling due to the ever-increasing need. In addition, petroleum-based lubricants have a negative impact on the environment because they have negative properties, including non-renewable, not environmentally friendly and toxic. Synthetic lubricants are chemicals with better characteristics than mineral and vegetable lubricants. Synthetic lubricants are formed from chemical compounds with quality specifications and are designed through a synthetic process to obtain lubricants with specific and desired characteristics. Synthesis of Ester Based Lubricants can be carried out by oligomerization, esterification and separation processes. This study will explain the separation process control system in the design of an Ester-Based Lubricant factory to maintain the stability of the production process in a factory. In this study the process to be controlled is the n-heptanoic acid separation process to recycle the intermediates used to produce Ester-Based Lubricant compounds. The control used is the Integral Proportional (PI) control using the Ziegler Nichols, Lopez and Autotuner methods. The controller performance parameters are calculated using the IAE (Integral Absolute Error), ISE (Integral Squared Error) and ITAE methods. (Integral of Time Multiplied by Absolute Error). In this study the optimum control setting was achieved by using the Autotuner method and the lowest root mean squared (RMS) was obtained by the Solver method."

"Filtrasi adalah salah satu teknik separasi padat-cair yang memiliki peran penting dalam berbagai industri termasuk ekstraksi dan pemulihan logam berharga. Efisiensi proses ini sangat bergantung pada sifat bahan yang terlibat dan kondisi operasional. Penelitian ini mengkaji pengaruh penambahan bahan aditif pada proses pemisahan logam, yaitu Sulfosuccinate Diestersebagai surfaktan, terhadap efisiensi proses separasi menggunakan mesin filter tekan otomatis VPA. Percobaan dilakukan dengan memberikan variasi konsentrasi surfaktan dalam rentang 100 gram/ton, 200 gram/ton, 300 gram/ton, dan variasi waktu pengeringan 100,120,140 detik pada suspensi . Proses filtrasi dilakukan dengan parameter operasi yang terkontrol, seperti tekanan dan waktu filtrasi. Efisiensi proses dievaluasi dengan mengukur , kadar kelembaban produk padatan hasil filtrasi dan kecepatan proses. Hasil penelitian ini mengungkapkan pengaruh signifikan konsentrasi surfaktan pada efisiensi proses, semakin tinggi konsentrasi surfaktan akan menurunkan kadar air dalam filter cake. Dengan menentukan konsentrasi yang optimal, dapat meningkatkan efisiensi pemisahan, mengurangi biaya operasional, dan mengurangi dampak lingkungan yang potensial. Temuan ini berkontribusi pada pengembangan proses separasi mineral yang lebih berkelanjutan dan efisien dalam aplikasi industri ekstraksi dan metalurgi.

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Filtration is a solid-liquid separation method that plays a crucial role in various industries, including the extraction and recovery of precious metals. The efficiency of this process is highly dependent on the properties of the materials involved and the operational conditions. This study investigates the impact of adding an additive material, specifically Sulfosuccinate Diester as a surfactant, on the efficiency of the metal separation process using an automatic VPA filter press machine. The experiments were conducted by varying the concentration of the surfactant in the range of 100 grams/ton, 200 grams/ton, 300 grams/ton, and the drying time at 100, 120, 140 seconds for the suspension. The filtration process was performed with controlled operating parameters such as pressure and filtration time. The efficiency of the process was evaluated by measuring the moisture content of the solid product resulting from filtration and the process speed. The results of this study reveal a significant influence of surfactant concentration on process efficiency, where higher concentrations of surfactant reduce the moisture content in the filter cake. By determining the optimal concentration, the separation efficiency can be improved, operational costs can be reduced, and potential environmental impacts can be minimized. These findings contribute to the development of more sustainable and efficient mineral separation processes in extraction and metallurgical industrial applications."

"Graphene aerogel polyurethane sponge (GAPU) dibuat dari grafit yang dioksidasi dengan metode Hummer menjadi grafena oksida (GO) kemudian ditambahkan polyurethane sponge (PU) untuk direduksi menjadi reduced graphene oxide polyurethane sponge lalu di freeze-dried untuk mengubah bentuknya menjadi aerogel. Dalam penelitian ini bertujuan untuk menentukan nilai ekonomis produksi GAPU sebagai adsorben untuk separasi minyak-air. Pada studi ini, dibuat tiga skenario produksi GAPU, yaitu 547, 6000 dan 12000 ton. Hasil menunjukkan nilai keekonomian GAPU dengan kapasitas 547 ton dengan harga jual US$ 10,50 / Kg adalah NPV (net present value) sebesar US$ 1.326.996, BEP (break event point) sebesar 44,21 %, IRR (internal of rate return) sebesar 15,53% dan PBP (pay back period) sebesar 6,48 tahun. Sedangkan untuk kapasitas 6000 ton dengan harga jual US$ 2,80 / Kg adalah NPV sebesar US$ 10.773.480, BEP sebesar 33,01%, IRR sebesar 26,18 % dan PBP sebesar 2,21 tahun. Skenario ketiga dengan kapasitas paling tinggi, yaitu 12000 ton dengan estimasi harga jual sebesar US$ 2,20 / Kg adalah NPV sebesar US$ 18.219.424, BEP sebesar 27,10 %, IRR sebesar 33,92 % dan PBP sebesar 2,19 tahun. Nilai keekonomian produksi GAPU lebih baik jika diproduksi dalam kapasitas 12000 ton dibandingkan dengan kapasitas 6000 ton dan 547 ton. Analisis sensitifitas jika harga jual produk turun 10% lebih berpengaruh buruk terhadap nilai keekonomian dibandingkan harga bahan baku naik 10%. Akhirnya, analisis ekonomi dengan syarat harga jual kurang dari (<) sebesar US$ 18,18 / Kg, NPV > 0, BEP < 50% and IRR > 15% dinyatakan produksi Graphene Aerogel Polyurethane Sponge (GAPU) dinyatakan layak dan bernilai ekonomi tinggi

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In this study, graphene aerogel polyurethane sponge (GAPU) has been made from graphite, and it was then oxidized by the modified Hummer method to be graphene oxide (GO). The reduced graphene oxide was blended into polyurethane sponge (PU), and this graphene oxide-polyurethane sponge composites was freeze-dried into an aerogel to change their shapes. This study was aimed to determine the economic value of GAPU composites as an adsorbent to separate oil-water. Three different scenarios of GAPU were designed, namely 547; 6,000 and 12,000 tons. The economic values of GAPU with a capacity of 547 tons and selling price of US$ 10.50 / kg were the NPV (net present value) of US$ 1,326,996, BEP (break event point) of 44.21%, IRR (internal of rate return) of 15.53% and PBP (payback period) of 6.48 years. While for the second scenario with capacity of 6000 tons with a selling price of US$ 2,80 / Kg were an NPV of Rp US$ 10,773,480, BEP of 33.01%, IRR of 17.32% and PBP of 2.21 years. The third scenario with capacity of 12,000 tons with an estimated selling price of US$ 2,20 / Kg showed an NPV of US$ 18.219.424, BEP of 27.10%, IRR of 33.92% and PBP of 2.19 years. The economic values of GAPU production was the best for capacity of 12,000 tons. Sensitivity analysis with a selling price of the product decreases by 10%, it has a more negative effect on the economic value than the price of raw materials increases by 10%. Overall, the economic analysis with the parameter condition such as the selling price is less than (<) of US$ 18,18 / kg, NPV > 0, BEP < 50% and IRR > 15% concluded that the production of Graphene Aerogel Polyurethane Sponge (GAPU) was feasible and had high economic value.

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"Perkembangan metode selektif reduksi dilakukan untuk mengolah bijih nikel laterit untuk menghasilkan kadar nikel yang tinggi tanpa menggunakan energi yang besar. Batubara bituminous umum digunakan pada proses selektif reduksi karena kandungan fixed carbon yang tinggi untuk meningkatkan derajat metalisasi nikel dan besi. Penambahan CaO pada basisitas biner dapat membentuk senyawa silikat seperti akermanite. Penelitian ini akan mempelajari proses selektif reduksi bijih nikel laterit menggunakan reduktor batubara bituminous dengan aditif Na2SO4 dan CaO pada basisitas biner. Penelitian ini menggunakan bijih nikel limonit dengan kandungan 1,38% Ni dan 38,2% Fe dengan penambahan aditif natrium sulfat 10% berat (Na2SO4), variasi soikiometri 0,1-0,5 dan variasi penambahan CaO pada basisitas biner 0,1-1,0. Penelitian ini bahwa hasil optimum pada stoikiometri 0,1 dan basisitas 0,1 yaitu 6,142% Ni dengan recovery 89,94%. Grade nikel menurun dengan bertambahnya jumlah CaO pada basisitas biner.

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Selective reduction methods are being developed to process nickel laterite ore to produce nickel with high content with small amount of energy. Bituminous coal is commonly used in selective reduction process because of its high fixed carbon content to increase degree of metallization of nickel and iron. CaO addition on binary basicity can form silicate compound like akermanite. This research was carried out to study selective reduction process nickel laterite ore using bituminous coal with additives Na2SO4 and calcium oxide on binary basicity. This research used limonite ore with 1.38% Ni and 38.2% Fe content. The reduction was conducted at 1150°C for 60 minutes with 10 wt.% additive sodium sulphate (Na2SO4) and 0.71% S bituminous coal with stoichiometric variations of 0.1-0.5 and CaO based on binary basicity variations of 0.1-1.0. This research shows that the reduction process with stoichiometry 0.1 and basicity 0.1 produced the most optimal grade and nickel recovery, 6.142% Ni and 89.94%. The recovery of nickel decline as the ratio of CaO in binary basicity increases."

"Anomali Bouguer dalam survey gravitasi merupakan jumlah medan gravitasi yang dihasilkan oleh semua sumber anomali bawah permukaan, yaitu anomali regional dan residual. Anomali regional berasosiasi dengan frekuensi rendah dan anomali residual diidentifikasi dengan frekuensi tinggi yang mengandung informasi mengenai sumber anomali dangkal. Target dalan eksplorasi geofisika pada umumnya struktur-struktur kecil pada kedalaman yang dangkal. Hal inilah menyebabkan pemisahan anomali regional dan residual sangat penting dalam interpretasi data gravitasi. Pemisahan anomali dilakukan dengan variasi metode, yaitu, polynomial trend surface analysis, upward continuation dan lowpass frequency filter. Metode-metode tersebut di aplikasikan menggunakan model sintetik yakni model Syn dan model Intrusi. Hasil dari ketiga metode untuk memisahkan komponen regional dan residual kemudian ditampikan dan dibandingkan. Dari hasil penelitian, diperoleh bahwa anomali regional dan residual yang diasilkan oleh metode polynomial trend surface analysis mempunyai error yang paling minimum diantara kedua metode lain yang digunakan. Rms error anomali regional berturut-turut untuk metode polynomial trend surface analysis, upward continuation and lowpass filter dari model Syn adalah 0,706 mgal, 0,785 mgal, 0,766 mgal and dari model Intrusi yakni 0,410 mgal, 0,451 mgal, 0,540 mgal.

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Bouguer anomaly in gravity surveys are the sum of gravity fields produced by all underground sources, from residual and regional anomaly. Regional anomaly is identified by low frequency and residual anomaly is identified by high frequency that contains information of shallow sources. The targets for geophysical surveys are often small scale structure buried at shallow depths. That's why regionalresidual field separation is essential in gravity data interpretation. A variety of separation techniques have been proposed, namely, polynomial trend surface analysis, upward continuation and lowpass frequency filter. The proposed methods were tested using variation of synthetic models, that are, Syn and Intrusion 3D models.

Results from three methods to separate residual and regional component are presented, compared and evaluated. The results show regional and residual anomaly produced by polynomial trend surface analysis have minimal error than two other methods. The rms errors of regional anomaly of Syn model are 0.706 mgal, 0.785 mgal, 0.766 mgal and rms errors of regional anomaly of Intrusion model are 0.410 mgal, 0.451 mgal, 0.540 mgal for polynomial trend surface analysis, upward continuation and lowpass filter, respectively."

"ABSTRAKTurbin angin adalah salah satu sumber energy alternatif yang ramah lingkungan. Blade yang digunakan pada turbin angin umumnya berbentuk aerofoil. Pada aliran dengan bilangan reynold yang rendah atau aliran laminar, aliran di aerofoil cenderung mengalami separasi yang menyebabkan adanya gaya hambat (drag) yang membuat energy yang dihasilkan oleh turbin angin menjadi tidak efektif. Salah satu cara untuk mengurangi gaya hambat itu adalah dengan memberikan energy tambahan berupa tiupan dan hisapan pada permukaan aerofoil agar udara dapat mengalir dan tidak terjadi separasi. Dari hasil simulasi, pemberian tiupan dan hisapan dapat mengurangi gaya hambat hingga sebesar 16 %.

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ABSTRAKWind turbines tends to be one source of alternative energy that is environmentally friendly. Blade used on wind turbines generally shaped airfoil. In streams with low Reynolds number or laminar flow, flow in the airfoil tends to separated and induced drag that make the energy generated by wind turbines become ineffective. One way to reduce the drag it is to provide additional energy in the form of blowing and suction on airfoil surface so air can flow past through and there is no separation happen. From the simulation, giving blowing and suction to reduce drag by up to 16 %"