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Pengaruh Penambahan Silica Fume, Rasio Air-Semen, dan Rasio Semen-Agregat Terhadap Kekuatan Tekan Beton Aditianto Ramelan; F.N. Sutandi; T. Indriati; A.S. Nugroho; A. Rozaq; R. Rachmantyo
Jurnal Metalurgi dan Material Indonesia Vol. 1 No. 1 (2018): Agustus
Publisher : Badan Kerja Sama Pendidikan Metalurgi dan Material (BKPMM)

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Abstract

Concrete is a popular building structures because it is relatively cheap, has a good strength, durable, and has easy raw materials. Therefore, various researches have been done to improve the quality of concrete, such as using mineral admixtures like silica fume and variations of aggregate. This research is done by making concrete sample for compressive strength test. The variations are the addition of silica fume (SF) with the composition of 10, 15, and 20% of mass of concrete, the ratio of water-cement (w/c), and the cement-aggregate ratio (c/a) with the composition of 0.6; 0.8; and 0.9 for 28 day test age. The aggregate used is silica sand. From the test results, the maximum compressive strength is 33.73 MPa from the sample with the composition of w/c = 0.4; SF = 15%, and c/ a = 0.9 which is higher than cement sample that has 20.85 MPa. Its compounds, which are identified with the XRD characterization, are Calcite, Quartz, Calcium Silicate Hydrate (CSH), Calcium Silicate, and Portlandite. There is also cement sample with silica fume (w/c = 0.4; SF = 10%) that has a compressive strength of 24.26 MPa. The compounds identified are Calcite, CSH, Calcium Silicate, Ettringite, and Portlandite. Addition of silica fume on cement can increase its compressive strength due to the occurrence of pozzolanic reaction. This is evidenced by the increase of CSH compounds and reduction of Portlandite compounds on the results of XRD characterization. The use of silica sand in the mix will increase concrete’s compressive strength because silica sand itself has greater compressive strength than the others.
Pengaruh Temperatur dan Rapat Arus Terhadap Kekerasan dan Distorsi Kisi pada Hard Chromium Plating pada Baja Karbon Rendah Riska Rachmantyo; Aditianto Ramelan; Akhmad Zein Eko Mustofa; Asep Ridwan Setiawan
Jurnal Metalurgi dan Material Indonesia Vol. 2 No. 2 (2019): Agustus
Publisher : Badan Kerja Sama Pendidikan Metalurgi dan Material (BKPMM)

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Abstract

Hard Chromium Plating is one of several coating techniques that has been applied to engineering components. The hard chromium layers have several properties such as, hardness, high corrosion and wear resistance. In fact the quality is determined by several process parameters during electro deposition. In this experiment temperature and current density were varied to observe the effect on the quality of hard chromium layer deposited on a steel base plate. This was to find the appropriate combination of producing deposited layer with the optimum quality. The electroplating process was carried out for 60 minutes at 50, 55 and 60 oC with current density variation of 70, 80 and 90 A/dm2. The specimen were then undergone hardness test and XRD characterization. Maximum hardness measured was 1128 HV this was plated at 55°C with a current density of 80 A/dm2. XRD analysis shown that the increasing hardness of hard chromium plating is related with an increase of microstrain calculated from the diffractogram pattern.
KAJI EKSPERIMENTAL DAN NUMERIK TENTAN G FAKTOR KETANGGUHAN RETAK MODUS I DAN II PADA LAMINATE KARBON/EPOXY SERAT TERANYAM IGN Wiratmaja Puja; Rochim Suratman; Aditianto Ramelan; Hariadi Tri Prasetia
Mesin Vol. 15 No. 3 (2000)
Publisher : Mesin

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Abstract

This paper presents experimental and numerical analysis on the influence of crack orientations to the fracture toughness of mode I and mode II for woven type carbon/epoxy four ply laminate. The experimental procedure is carried out through off axis tensile test (ASTM D 3039-76) with nine variation of crack orientations i.e. 5°, 10°, 15°, 30°, 45° 65°, 75°, 80°, and 90°. Three rail shear test (ASTM D 4255-83) is utilized for zero degree crack orientation. The stress and strain contours around crack tips are obtained numerically using the finite element method. Numerical and experimental results of the mode I (KI) and mode II (KII) fracture thoughness are presented in graphical form as a function of crack directions. Adopting Wu's(11) Criteria for unidirectional lamina and Hahn's[6] Criteria for general anisotropic lamina, a new mixed mode fracture toughness criteria is developed for woven fiber matrix laminate.
Surfaces Casting Defect Analysis and its Countermeasures on Products Manufactured by Alkali-Phenolic Binder Sand Molding Husen Taufiq; Aditianto Ramelan; Ekavianty Prajatelistia; Susana Susana; Muhammad Fathurrohman
Jurnal Metal Indonesia Vol 44, No 1 (2022): Metal Indonesia
Publisher : Balai Besar Logam dan Mesin

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32423/jmi.2022.v44.35-41

Abstract

This paper presents the results of the analysis of surface casting defects and their countermeasures. To find out the root causes of defects, and their mechanisms. Product casting defects have been characterized by visual inspection and SEM/EDX, also collecting production data information. Studied relation between the composition of molding sand and the mechanical properties of compressive strength and surface stability index has been done. The visual inspection results, field data collection, and SEM/EDX analysis showed a rough product surface and the presence of SiO2 inclusions. The product has been made with an alkaline phenolic mold using reclaimed sand with a compressive strength of 18 kg/cm2. The study results show that with increasing binder levels, there is an increase in the mechanical properties of compressive strength and surface stability index. They were based on the experimental results of the test block product casting with improved mechanical properties above. Obtained a much better surface of the casting product, and relatively no surface inclusion defects were found. The above experiment shows that the surface stability index is an important parameter the critical value is 90%, and the necessary compressive strength is 20 kg/cm2. The effect of Loss on Ignition content on mechanical properties is also reviewed.
Wristband Inovatif Penghilang Kantuk Saat Belajar dengan Sensor Detak Jantung Berbasis IOTc Azka Zakiyyatuddin; Aldo, Dian Afif; Aditianto Ramelan
JIIF (Jurnal Ilmu dan Inovasi Fisika) Vol 2, No 2 (2018)
Publisher : Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (342.175 KB) | DOI: 10.24198/jiif.v2i2.19714

Abstract

Salah satu permasalahan yang dihadapi oleh masyarakat Indonesia adalah keadaanmengantuk ketika melaksanakan berbagai aktivitas. Salah satunya seperti yang biasa dialami oleh pelajar ketika belajar atau ujian. Oleh karena itu, diperlukan sebuah alat untuk menghilangkan rasa kantuk pada saat menjalankan aktivitas. Kanmuru Wristband merupakan produk penghilang kantuk dengan basis teknologi sensor detak jantung. Kanmuru akan mendeteksi perubahan detak jantung pada pengguna, ketika detak jantung turun di bawah standar maka sensor akan mengkomunikasikannya melalui sistem nodeMCU kemudian meneruskannya ke aktuator vibration motor, buzzer dan/atau penyengat listrik sehingga akan ada getaran, suara nyaring, dan/atau sengatan listrik yang akan memberikan efek kejut kepada pengguna sesuai mode yang dipilih sehingga kantuk akan hilang. Selain itu, wristband ini dapat dihubungkan dengan android untuk memantau nilai BPM yang tercatat setiap waktunya, mengatur batasan BPM ngantuk, dan mengubah mode alat sesuai kebutuhan. Inovasi ini akan membantu mewujudkan SDGS poin ke-8 : Increasing labour productivity.