ANALISIS GAYA PADA REM CAKRAM (DISK BRAKE) PADA KENDARAAN RODA DUA (HONDA BEAT SPORTY 2017)

AbstrakPenelitian ini dilakukan untuk mengetahui besaran gaya yang terjadi pada rem cakram untuk kendaraan roda dua yang bertujuan bagi para pengendara agar lebih mengetahui serta paham ketika berkendara terutama pada saat melakukan pengereman, agar lebih aman pada saat berkendara. Karena salah satu kasus kematian yang terjadi di Indonesia yaitu karena kecelakaan lalu lintas, moda tranportasi yang banyak mengalami kecelakaan adalah sepeda motor, kejadian tersebut sebagai indikasi bahwa sepeda motor merupakan penyebab utama terjadinya kecelakaan lalu dan penyumbang korban terbanyak. Maka dari itu sebagai pengendara kita harus mengetahui serta memahami betul bagaimana cara nya berkendara terutama menggunakan sepeda motor serta mengetahui batas kapasitas berkendara ataupun kepecepatan yang ditempuh pada saat melakukan pengereman. Dalam analisis perhitungan dari komponen rem cakram motor beat sporty 2017 dengan data spesifik ; berat kendaraan 93 kg, berat 2 penumpang 130 kg, Kecepatan awal motor (vo) 80 km/jam sampai Kecepatan akhir motor (vt) 0 km/jam, Jarak pengereman sampai berhenti (s) 50 m, Koefisien gesek pada asbes (?) 0,31, Diameter kaliper rem (Dkaliper) 32 mm, Perlambatan pada titik kunci sinkron (?’) 0,6 g. Dari data yang sudah dipersiapkan dapat dilakukan perhitungan agar mendapatkan ; Gaya pada tuas rem (Handle) (F), Diameter Master Rem (Dmaster), Gaya pengereman pada daya maksimal (F), Waktu pengereman (t), Tekanan minyak (Pw), Momen rem, Beban Dinamis (WbD), Faktor efektivitas rem (FER), Energi kinetis (Ek), Perlambatan dalam keadaan darurat (?'), Waktu rem sesungguhnya (te), Luas lapisan (ALD), Kapasitas energi lapisan (KLD), Kapasitas rem. Jika semua sudah diketahui dan dipahami oleh pengendara maka pengendara akan lebih tau kapasitas yang aman dalam berkendara dan melakukan pengereman pada saat berkendara.Kata kunci: Rem, Rem Cakram, Kendaraan Roda dua

A new crescent moon visibility criteria using circular regression model: a case study of Teluk Kemang, Malaysia

Many astronomers have studied lunar crescent visibility throughout history. Its importance is unquestionable, especially in determining the local Islamic calendar and the dates of important Islamic events. Different criteria have been used to predict the possible visibility of the crescent moon during the sighting process. However, so far, the visibility models used are based on linear statistical theory, whereas the useful variables in this study are in the circular unit. Hence, in this paper, we propose new visibility tests using the circular regression model, which will split the data into three visibility categories; visible to the unaided eye, may need optical aid and not visible. We formulate the procedure to separate the categories using the residuals of the fitted circular regression model. We apply the model on 254 observations collected at Baitul Hilal Teluk Kemang Malaysia, starting from March 2000 to date. We show that the visibility test developed based on elongation of the moon (dependent variable) and altitude of the moon (independent variable) gives the smallest misclassification rate. From the statistical analysis, we propose the elongation of the moon 7.28°, altitude of the moon of 3.33° and arc of vision of 3.74 at sunset as the new crescent visibility criteria. The new criteria have a significant impact on improving the chance of observing the crescent moon and in producing a more accurate Islamic calendar in Malaysia

Analysis data of the 22 years of observations on the young crescent moon at Telok Kemang observatory in relation to the Imkanur Rukyah criteria 1995

The main challenge in the young crescent moon (YCM) observation is the ability to detect the appearance of the YCM, which has varying contrast due to the phenomenon of twilight. The advancement of technology in digital imaging helps the faint and thin image of the YCM to be detected and taken during observation. The techniques used in the observations of the YCM were naked eyes, telescope, and telescope with cameras. A digital imaging technique is also being used in the observations to assist in detecting and recording the image of the YCM more effectively. This paper presents the analysis of the YCM observation data recorded at Telok Kemang Observatory from 2000 to the present. A total of 275 observation sessions were conducted during this study, with 87 positive sightings successfully recorded. The studies found that the smallest elongation and the minimum altitude at sunset of the YCM successfully recorded were 6.81° and 5.40°, respectively. The moon was recorded at an altitude of 3.37°, while the sky is still bright with the sun at an altitude of –2.64° using the digital imaging technique. Based on the records, the YCM which has the minimum criteria of Imkanur Rukyah, i.e., altitude of 2° and elongation of 3° at sunset was never detected or recorded during the 22 years of observations. Therefore, this work suggests the need to change the visibility of Imkanur Rukyah criteria used since 1995 to a more potentially observable criterion. In other aspects, the lengthy observation activities have contributed to the development of a database system for JAKIM that other researchers can access

Study of Corrosion in Biocompatible Metals for Implants: A RevieW

High requirements in biomedical applications are yet to be met, equally in joint and bone substitution and the healing and renewal of bone weaknesses. The compatibility with the human body is the main precondition for the choice of biomaterials, which should thus have some significant properties that will be durable for use in the body without rejection. This paper concentrates, especially, on biocompatible metals, although there are also biomaterials made of polymers, ceramics, and composite materials. Considerations in selecting materials for biomedical applications such as biocompatibility, the high corrosion and wear resistance, and osseointegration are discussed. This paper reviews the applications of three main types of biocompatible metal, namely, stainless steels, cobalt-chromium alloys, and titanium and its alloys. The corrosion resistance of each alloy is in focus. It can be confidently declared that biocompatible metals will continue to be used as biomaterials in the future with further improvements and new revolutionary bio-functionalities in the use of metals