Corrosion behavior of brass in nitric acid

This research is a preliminary study of which purpose is to find some information about corrosion behavior of brass casted product in nitric acid. The corrosion rate test was conducted by polarization and Electrochemical Impedance Spectroscopy (EIS). This study was run with the variation of nitric acid of 0,5; 1; 1,5; 2 M. Optical Microscope (OM) were used to explain and to confirm polarization and EIS result. A mechanism for the reactions taking place at the electrode/electrolyte interface was explained

Rancang Bangun Aplikasi Data Mining Analisis Tingkat Kelulusan Menggunakan Algoritma Fp-growth (Studi Kasus di Politeknik Negeri Malang)

Kondisi  kompetisi  dan  tuntutan  oleh  Direktorat  Jenderal  Pendidikan  (Dikti)  membuat  perguruan  tinggi harus memiliki keunggualan kompetitif dan kualitas agar dapat tetap bersaing dengan perguruan-perguruan tinggi lainnya. Teknologi informasi merupakan salah satu sumber daya yang dapat meningkatkan keunggulan bersaing dan dapat digunakan untuk mengolah informasi, menyebarkan informasi, serta pengambilan keputusan strategis. Tersedianya suatu informasi tidak terlepas dari melimpahnya data, dari pengolahan dan penggalian data tersebut informasi dapat diperoleh. Teknologi yang berkaitan dengan mengolah dan penggalian data menjadi informasi yang berguna adalah data mining. Teknologi data mining memiliki berbagai macam algoritma dan teknik untuk penyelesaian  masalah yang  berhubungan  dengan  data  salah  satunya  adalah  algoritma fp-growth dan  teknik association rules. Dari uraian diatas dapat dibuat sebuah aplikasi untuk menganalisis tingkat kelulusan melalui teknik  data  mining  menggunakan  algoritma fp-growth.  Informasi  yang  ditampilkan  menggunakan  teknik association rules yaitu menampilkan nilai support dan confidence dari masing-masing proses mining. Terbukti dari hasil pengujian yang dilakukan, algoritma fp-growth dan teknik association rules berjalan sesuai harapan dan dapat diimplemantasikan pada aplikasi data mining ini

Fatigue crack growth behavior of nodular cast iron subjected to two-step austempering

This research aimed to investigate the fatigue crack behaviorof nodular cast iron heat-treated with two-step austempering. In this study, the material was initially reheated at 260 °C for 10 minutes, and then the temperature was increased to 280 °C, 310 °C, and 340 °C with the holding time of 60 minutes and 120 minutes. The results of these treatments showed that slower fatigue crack propagation occurred at the austempering temperature of 340 °C with 60-minutes holding time than those at lower temperatures (280 °C and 310 °C) and with longer time (120 minutes). The maximum fatigue crack propagation resistance occurred at the holding time of 60 minutes compared to that at the 120 minutes holding time

Wear behaviour of cast aluminium silicon (Al-Si) alloy in dot 4 brake fluid

Abstract : The frictional sliding behaviour of cast Al-Si alloy was investigated with and without DOT 4 hydraulic brake fluid lubrication/environments. Cast Al-Si specimen was produced from wrought alloy and the specimen surface was metallurgically prepared. The as- cast product was characterized with aid of micro-hardness tester, the chemical composition was analysed by X-ray fluorescence (XRF), while X-ray diffraction (XRD) was used to identify phases present, microstructures and surface examinations were done on a high resolution metallurgical Optical Microscope. The properties of the polished and worn sample surfaces were examined by Scanning electron microscope (SEM) equipped with Energy dispersive X- ray (EDS) facilities. A 6mm diameter alumina ball under varying normal loads (3-10 N) was rubbed against the surface of the cast Al-Si coupon specimen. The dry and wet sliding wear behaviour was assessed based on the CoF-sliding time behaviour. From the results, the average CoF values of 0.9064 for dry and 0.2038 for wet contacts were obtained. Comparatively, 1.03E-06 and 4.21E-07 minimum wear intensities; and 467290 and 132170 wear resistances were obtained for dry and wet contacts respectively. Behaviour of cast Al-Si in DOT4 were compared with its performance in DOT3 regarding the hydraulic brake system application

The inhibitive effect of tannin in Psidium guajava leaves towards 304SS corrosion in concentrated HCl

Tannin isolated from Psidium guajava leaves are developed to enhance the corrosion protection of austenitic stainless steel. It is used as a green inhibitor, extracted from Psidium guajava which grow in East java, Indonesia. In the present work, the corrosion inhibition properties of the tannin inhibitors were investigated in 3M HCl by polarization potentiodynamic measurements. The result reveals that tannin 1g/L could enhance the inhibition efficiency up to 91.81%