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Perancangan Anticlimber sebagai Perangkat Crashworthiness untuk Kereta Penumpang Indonesia
Get PDFAnticlimber merupakan komponen pengaman untuk meningkatkan aspek crashworthiness, yang berfungsi khusus mencegah terjadinya fenomena overriding (tumpang tindih) saat tumburan kereta api yang dapat menyebabkan dampak jatuhnya korban jiwa yang signifikan. Sebagai rangkaian riset dan pengembangan untuk menerapkan teknologi crashworthiness pada kereta penumpang nasional, dikembangkan rancangan anticlimber yang sesuai dengan kereta penumpang produk industri nasional saat ini. Rancangan menggunakan konsep ribs terpisah yang dipasang pada kedua ujung kereta tepat di kanan dan kiri coupler. Anticlimber dirancanga sehingga dapat diintegrasikan dengan mudah tanpa terlalu lama mengganggu operasional KA, dan dapat diproduksi di dalam negeri dan tentunya efektif menahan gerakan vertikal (climbing) antar kereta. Analisis keefektifan rancangan anticlimber ini diuji dengan simulasi beban statik maupun beban dinamik berdasarkan kriteria standar internasional, yaitu BS EN 13227 yang dinilai paling lengkap mengatur aspek crashworthiness di perkeretaapian. Dari analisis kekuatan statik yang telah dilakukan, terbukti bahwa rancangan mampu menahan beban gaya longitudinal 60 tonf (177,6 kN) dan gaya angkat vertikal 12 tonf (588 kN) dan saat terjadi tumburan. Sedangkan dari simulasi dinamik pada kecepatan tumburan 10 m/s (36 km/jam), sesuai kriteria BS EN, dan kecepatan tinggi 20 m/s (72 km/jam), keberadaan anticlimber terbukti memenuhi standar dan mampu menurunkan kemungkinan terjadinya tumpang tindih, dibandingkan jika tanpa antilimber. Dengan hasil ini, dapat disimpulkan bahwa rancangan memiliki prospek yang baik untuk dikembangkan ke purwarupa dan pengujian lapangan, yang menjadi tahap berikutnya dari penelitian ini.Anticlimber merupakan komponen aspek crashworthiness, yang berfungsi khusus mengurangi kemungkinan terjadinya fenomena overriding (tumpang tindih) saat terjadi tumburan kereta api yang dapat menyebabkan dampak jatuhnya korban jiwa yang signifikan. Sebagai rangkaian riset dan pengembangan untuk menerapkan teknologi crashworthiness pada kereta penumpang nasional, dikembangkan rancangan anticlimber yang sesuai dengan kereta penumpang produk industri nasional saat ini. Rancangan menggunakan konsep rusuk (ribs) terpisah yang dipasang pada kedua ujung kereta tepat di kanan dan kiri coupler. Anticlimber dirancang sehingga dapat diintegrasikan pada rancangan kereta penumpang yang ada, dan dapat diproduksi di dalam negeri di samping tentunya efektif menahan gerakan vertikal (climbing) antar kereta. Analisis keefektifan rancangan anticlimber ini diuji dengan simulasi beban statik maupun beban dinamik berdasarkan kriteria standar internasional, yaitu BS EN 15227 yang dinilai paling lengkap mengatur aspek crashworthiness di perkeretaapian. Dari analisis kekuatan statik yang telah dilakukan, terbukti bahwa rancangan mampu menahan beban gaya longitudinal 60 tonf (177,6 kN) dan gaya angkat vertikal 12 tonf (588 kN) saat terjadi tumburan. Berdasarkan hasil simulasi dinamik pada kecepatan tumburan 10 m/s (36 km/jam), sesuai kriteria BS EN, dan kecepatan tinggi 20 m/s (72 km/jam), keberadaan anticlimber terbukti memenuhi standar dan mampu menurunkan kemungkinan terjadinya tumpang tindih, dibandingkan jika tanpa antilimber secara signifikan. Dengan hasil ini, dapat disimpulkan bahwa rancangan memiliki prospek yang baik untuk dikembangkan ke purwarupa dan pengujian lapangan, yang menjadi tahap berikutnya dari penelitian ini
Study of Geometric Modification of Calciner in Cement Plant
No full textSuspension preheater is a raw mix pre-heating equipment used in a cement plant. The heat is used to raise raw mix temperature up to 800 0C -900 0C. The process results in an 80-90% degree of calcination. In this project, an increasing percentage of calcination in suspension preheater and reducing the load in the kiln is attempted, by including the calciner in suspension preheater. This project will focus on a suspension preheater system with a separate line calciner (SLC) at Cement Plant with 5000 ton per day (TPD) capacity. Calciner in existing conditions will be modified by extending its length by 2.5 m. Computational fluid dynamics (CFD) method was chosen to simulate the performance of the calciner. The results show that the alternative design can increases calcination percentage up to 76,32%, from the original value of 71%. The heat transfer on the alternative design also increases by 9%. As a result, the temperature output of the cyclone 5 also decreases, reducing the heat consumption. Another consequence of the alternative design is the possibility to increase the production capacity while maintaining the outlet temperature of cyclone 5, by increasing raw mix feeding without additional fuel consumption. Thus, clinker production can be increased by 8%.In a cement plant, suspension preheater is used to raise temperature of a raw mix so that the mixing process results in a high degree of calcination. In this research project, we attempt to increase degree of calcination to reduce the load in the kiln by including the calciner suspension pre-heater. This project focus on a suspension preheater system with a separate line calciner at cement plant with capacity of 5000 ton per day. Then the calciner will be modified its length. Computational fluid dynamics method was chosen to simulate the performance of the calciner. The results show that the modified calciner can increases the degree of calcination and improves the heat transfer rate. This lead to the decrease of temperature output of the top cyclone and thus reducing the heat consumption. Which such efficiency, the modification design opens possibility to increase the production capacity while maintaining the outlet temperature of the top cyclone
Kajian Material Komposit Sandwich pada Floor Panel Pesawat Terbang
Get PDFSandwich composites have been used as lightweight materials in aircraft manufacturing for a long time, from balsa wood sandwich in the 1930s to honeycomb and fiber-reinforced polymers sandwich. Its characteristics are considered as a 'perfect' material for aircraft, which has high strength with low density. Sandwich composites are the common materials for aircraft floor panels. The core is usually made of Nomex or aluminum honeycomb, while the skin is made of 1 "“ 2 ply of carbon/glass fiber in epoxy resin composite. The core is usually constructed using the corrugating or expansion method, whilst the skins are usually constructed using the prepreg lay-up method. Both materials are combined together by a simple adhesive bonding. Being the most strictly regulated transportation method on the planet, floor panel manufacturers must abide by aircraft manufacturing companies and local aviation authority standards and specifications to ensure the product's safety. The purpose of this study is to determine the most used materials for aircraft floor panels and why is it widely used, to understand the manufacturing process, and to know the specifications and standards that need to be fulfilled.Sejak dahulu, komposit sandwich telah umum digunakan dalam proses manufaktur komponen pesawat terbang dimulai dari sandwich kayu balsa sejak tahun 1930-an hingga sandwich honeycomb dan polimer berpenguat serat. Karakteristik dari material sandwich tersebut dipandang sebagai material yang tepat untuk digunakan dalam proses manufaktur pesawat terbang karena memiliki sifat mekanik spesifik yang tinggi. Komposit sandwich umumnya digunakan dalam proses pembuatan panel lantai pesawat terbang. Nomex dan alumunium foam merupakan material yang umum digunakan sebagai core pada material sandwich, sedangkan material skin yang umum digunakan merupakan komposit epoksi berpenguat serat karbon/serat gelas. Material core umumnya dibuat dengan menggunakan metode corrugating dan ekspansi, sedangkan material kulit dibuat dengan menggunakan metode prepreg lay-up. Kedua material tersebut digabungkan bersama dengan menggunakan metode adhesive bonding. Produsen panel lantai pesawat terbang harus mematuhi standar dan spesifikasi otoritas penerbangan setempat untuk memastikan keamanan produk. Tujuan dari penelitian ini adalah untuk mengidentifikasi material yang umum digunakan dalam proses pembuatan panel lantai pesawat terbang, alasan dari penggunaan material tersebut, memahami proses pembuatannya serta mempelajari spesifikasi dan standar yang harus dipenuhi panel lantai pesawat terbang
FENOMENA META, SINERGI 3 PLATFORM MEDIA SOSIAL: FENOMENA META, SINERGI 3 PLATFORM MEDIA SOSIAL
No full textMetaPlatform Inc. started with Facebook in 2004 and expanded after taking over Instagram, WhatsApp, Beluga and Oculus VR. This article reviews why and how Meta Platform Inc. developed Facebook, then took over and developed other platforms that make global social media play a significant role in various aspects of users' lives. Social media users, in various age groups have their own preferences in making choices to use their social media platforms. In this study, the authors limit it to 4 social media platforms, all of which are owned by Meta Platform Inc., namely: Facebook, Messenger, Instagram and Whatsapp, and their effects on users in the middle age group (40-60 years). Text analysis and user behavior in interacting and participating in using and following the dynamics of the four platforms. The results of this study show that the middle-aged generation tends to use primary features on the platform. Key features like photo sharing, text messaging and social interaction remain the main attraction for users in this age group.Meta Platform Inc. berawal dari Facebook pada tahun 2004 kemudian berkembang setelah mengambil alih Instagram, WhatsApp, Beluga dan Oculus VR. Artikel ini mengulas mengapa dan bagaimana Meta Platform Inc. mengembangkan Facebook, kemudian mengambil alih dan mengembangkan platform lainnya yang menjadikan media sosial global berperan signifikan dalam berbagai sisi kehidupan pengguna. Pengguna media sosial, dalam berbagai kelompok usia mempunyai preferensi masing-masing dalam menentukan pilihan untuk menggunakan platform media sosialnya. Dalam penelitian ini, penulis membatasi pada 4 platform sosial media, yang keempatnya dimiliki Meta Platform Inc., yakni: Facebook, Messenger, Instagram dan Whatsapp, serta pengaruhnya pada pengguna di kelompok usia paruh baya (40-60 tahun). Analisis teks dan perilaku pengguna dalam berinteraksi dan berpartisipasi dalam menggunakan dan mengikuti dinamika keempat platform tersebut. Adapun hasil penelitian kali ini menunjukkan bahwa generasi paruh baya cenderung menggunakan fitur-fitur primer pada platform tersebut. Fitur utama seperti berbagi foto, pesan teks, dan interaksi sosial tetap menjadi daya tarik utama bagi pengguna dalam kelompok usia ini
Pengaruh Kemacetan di Jalan Raya Kopo Terhadap Perilaku Aggressive Driving Pengendara Motor
No full textBandung has become Indonesia’s most congested city, based on a survey from the Asia Development Bank in October 2019. Traffic congestion can affect a person’s physical and psychological condition. This situation encourages a driver to behave aggressively to quickly reach their destination. This study aims to analyze the effect of traffic congestion on Jalan Raya Kopo on the motorcyclists’ aggressive behavior. The method used is quantitative- descriptive. Data was collected through a questionnaire distributed to 100 respondents with the criteria of motorcyclists who frequently passes Jalan Raya Kopo, aged 17-35 years. The researcher tested the classical assumptions, which included tests for normality, multicollinearity, and heteroscedasticity. Then an analysis with a simple regression analysis in the form of F test, t test, and R2 is used to analyze the effect of congestion on aggressive driving. The results showed that congestion influenced aggressive driving behavior by 28.9%, while the other 71.1% were influenced by other variables outside the test in this study.Kota Bandung berada pada urutan pertama kota termacet se-Indonesia berdasarkan survei dari Asia Development Bank pada bulan Oktober 2019. Situasi kemacetan dapat memengaruhi kondisi fisik dan psikologis seseorang. Situasi tersebut mendorong seorang pengendara untuk berperilaku aggressive driving agar cepat sampai ke tempat tujuan. Penelitian ini bertujuan untuk menganalisis pengaruh kemacetan di Jalan Raya Kopo terhadap perilaku aggressive driving pengendara motor. Metode yang digunakan yaitu deskriptif kuantitatif. Data dikumpulkan melalui kuesioner yang disebar kepada 100 orang responden berdasarkan kriteria seorang pengendara motor dengan frekuensi sering melewati Jalan Raya Kopo berusia 17-35 tahun. Peneliti melakukan pengujian asumsi klasik yang mencakup uji normalitas, multikolinearitas, dan heteroskedastisitas. Kemudian dilakukan analisis dengan analisis regresi sederhana berupa uji F, uji t, dan R2 untuk menganalisis pengaruh kemacetan terhadap aggressive driving. Hasil penelitian menunjukkan bahwa kemacetan berpengaruh terhadap perilaku aggressive driving sebesar 28,9%, sementara 71,1% lainnya dipengaruhi variabel lain di luar pengujian dalam penelitian ini
Analisis Statik Bus Konversi Listrik Berbasis Ladder Frame Chassis
Get PDFKonversi kendaraan Internal Combustion Engine (ICE) menjadi kendaraan Listrik dapat mempercepat peningkatan jumlah populasi Electric Vehicle (EV) yang mengurangi emisi gas carbon. Makalah ini menjelaskan proses analisis statik yang merupakan salah satu bagian penting saat mengkonversi bus berbasis ICE menjadi bus listrik. Bus yang dikonversi perlu memperhatikan pembebanan statik, khususnya berat dan posisi Center of Gravity (CoG) pada struktur sasis karena mempengaruhi performa Bus. Penimbangan massa dilakukan pada sasis untuk mengetahui letak CoG setiap kondisi. Massa sasis dengan muatan komponen elektrik setelah ditimbang adalah 2774 kg sedangkan massa sasis model CAD 2760,78 kg. Persentase error massa sasis pada CAD terhadap massa sasis hasil pengukuran cukup baik, yaitu 0,48%. Total perhitungan massa komponen elektrik dan upperstructure adalah 1612 kg dan 2854,4 kg. Analisis distribusi beban sepanjang sasis menggunakan pendekatan Finite Element Analysis dengan menerapkan metode analisis linear statik. Pembebanan komponen elektrik menghasilkan maksimum displacement 3,49 mm, von Mises stress 78,47 MPa dan reaction force -577,4 N pada sasis. Sedangkan, pembebanan total dengan menambahkan upperstructure menghasilkan maksimum displacement 4,58 mm, von Mises stress 83,95 MPa, dan reaction force -1174 N dengan nilai safety factor 5,24. Perbandingan error nilai defleksi suspensi depan dan belakang antara simulasi dengan teoritik adalah 4,99% dan 4,93%. Hasil investigasi menunjukan nilai kekakuan pada suspensi pegas daun depan dan belakang masing-masing sekitar 285 N/mm dan 320 N/mm. Selain itu, struktur sasis dengan pembebanan total mengalami tegangan maksimum di sekitar suspensi belakang.
Multi-Objective Finned-Tube Heat Exchanger Optimization Using a Genetic Algorithm
Get PDFHeat exchangers are a significant component in many industries, particularly in energy conversion systems. The design of heat exchangers itself is a complex process because it involves experience-based decisions, numerous variables and parameters, and some of them are competing with each other. Genetic Algorithms (GAs) are one of the first evolutionary algorithms which remains one of the most extensively used non-linear optimization methods today. This study explores the implementation of Non-Dominated Sorting Genetic Algorithm II (NSGA-II) for thermal design and optimization of a finned-tube heat exchanger. The chosen objective functions were minimizing the heat exchanger volume and minimizing the air side pressure drop. The decision variables for the design were tube outer diameter, number of tube rows, fin pitch, unit height, and unit width. The calculated parameters and estimated cost of both preliminary design and optimized design were also compared. The optimized design offered a bigger alternative design while meeting all the constraints according to standards and industrial needs. The optimization reduced annualized operational and maintenance costs by 228% and lowered air pressure drop by 413% with bigger heat exchanger volume of 12% compared to the preliminary design.Heat exchangers are a significant component in many industries, particularly in energy conversion systems. The design of heat exchangers itself is a complex process because it involves experience-based decisions, numerous variables and parameters, and some of them are competing with each other. Genetic Algorithms (GAs) are one of the first evolutionary algorithms which remains one of the most extensively used non-linear optimization methods today. This study explores the implementation of Non-Dominated Sorting Genetic Algorithm II (NSGA-II) for thermal design and optimization of a finned-tube heat exchanger. The chosen objective functions were minimizing the heat exchanger volume and minimizing the air side pressure drop. The decision variables for the design were tube outer diameter, number of tube rows, fin pitch, unit height, and unit width. The calculated parameters and estimated cost of both preliminary design and optimized design were also compared. The optimized design offered a bigger alternative design while meeting all the constraints according to standards and industrial needs. The annualized cost of the optimized design is only 30.4% of the preliminary design, and the air pressure drop can be reduced to 19.5% of the preliminary design, with a 12.4% increase in volume
Progress and Challenges of Biological Leaching of Heavy Metal in Coal Ash from a Power Plant
Get PDFBioleaching is a technique for reducing the heavy metal content of coal ash by using bacteria, fungi, or yeast. Previous studies in heavy metal bioleaching of coal ash discussed the factors affecting the process, but as yet there is little information on the challenges of using microorganisms. Therefore, this study aimed to obtain comprehensive information regarding the use of microorganisms in heavy metal bioleaching. Heavy metal concentrations in coal ash are low, and the metals are diverse. The components of coal ash are complexes that cannot leach certain heavy metals according to previous studies. These low concentrations and complex components make it difficult to investigate the bioleaching mechanism. The combination of biological and chemical interactions involves various components in this system. The high concentration of iron and heavy metal leached could be toxic for microorganisms. The process is influenced by several factors, such as particle size, pH, and pulp density. Most heavy metal bioleaching studies on coal ash have been conducted on a small scale to control conditions affecting the process. Bioleaching kinetics in coal is a liquid-solid reaction that can be represented by the shrinking core model, which was mainly used in this study
Community Perception of Social Media Marketing Activity on Instagram @VisitJawaTengah
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The use of social media has become a popular online activity. One of the most popular social media platforms is Instagram. Therefore, companies, institutions, and other tourism stakeholders mostly choose Instagram as the promotion medium. Promotion through Instagram is one form of social media marketing activity (SMMA). SMMA consists of several aspects, such as entertainment, customization, interaction, electronic word of mouth (e-WoM), and trendy. This study aims to determine the public’s perception of the social media marketing activity on Instagram (@VisitJawaTengah) during the COVID-19 pandemic in 2021. The research method used is descriptive-quantitative. The results of the study show that people have a positive perception of social media marketing activities on Instagram (@VisitJawaTengah).
Penggunaan media sosial telah menjadi aktivitas online yang populer dan Instagram menjadi salah satu yang terpopuler. Tak heran jika banyak perusahaan, institusi, dan pemangku kepentingan pariwisata memilih Instagram sebagai media promosi. Promosi melalui Instagram merupakan salah satu bentuk aktivitas pemasaran media sosial atau social media marketing activity (SMMA). SMMA terdiri dari beberapa aspek seperti entertainment, kustomisasi, interaksi, electronic word of mouth (E-WoM), dan trendi. Penelitian ini bertujuan untuk mengetahui persepsi masyarakat terhadap aktivitas pemasaran media sosial Instagram @VisitJawaTengah. Metode penelitian yang digunakan ialah kuantitatif desktriptif. Hasil penelitian menunjukkan masyarakat memiliki persepsi yang positif (baik) atas aktivitas pemasaran media sosial Instagram @VisitJawaTengah.
 
Familiarity and Overcoming of Uncanny Valley towards Computer-Generated Imagery Characters in Malaysian Film
Get PDFRecently, the idea of the uncanny valley has drawn interest in robotics and other scientific circles and popular culture. Several scholars have discussed its implications and reactions towards human-like robots. However, only several previous studies examined overcoming the uncanny valley for realistic looking computer-generated actors in films and animation. This seeks to examine the familiarity of participants with the use of digital characters as actors. This paper explains how computer-generated imagery (CGI) was used to create actors in Malaysian films, the uncanny valley characteristics that may affect the audience’s attention. The researcher has chosen visual stimuli consisting of 1 genuine human character and 1 less humanlike subject. A self-administered survey (n = 127) with sample film footage and photos were delivered online via email and social networks to responders. Surprisingly, based on the data, the human resemblance of the humanlike characters was substantially higher than expected. This research concluded that the artificial CGI characters had higher perceived eeriness if the character was highly familiar to the audience. As a result, the digital actor’s replacement an impression of eeriness and disbelief, which confirms the uncanny valley theory