The nitriding process can be effectively applied to steel with alloying elements. The higher the alloying element in the steel maximizes the mechanical properties, including hardness. However, the raw material can be costly, therefore using cheap materials (without alloys) is a challenge in increasing surface hardness through iron nitride formation. Furthermore Grey and nodular cast iron have different properties and characteristics in the structure. This research focuses on the ability of the cast-iron structure to affect the nitride layer formation. Gas nitriding was conducted in a fluidized bed reactor with a 550°C in 20 % N2 and 80 % NH3 atmosphere at a flow rate gasses of 0.7 m3/hr process temperature and holding for 2, 4, and 6 hours. Tests are conducted by observing the depth of hardening, SEM, and EDAX. According to the results, the nitriding process increases the surface hardness of cast iron. The highest hardness value is nodular cast iron with a holding time of 6 hours (345 HV) and a hardening depth of up to 20-micron meters. The compounds formed in the nitride layer include FeN, Fe2-3N, Fe4N, and Fe2N. The compound formed is strongly influenced by the treatment time. Furthermore, the comparison of nitriding treatment on gray and nodular cast iron was influenced by the flake and nodule structure. In general, the nodule structure is responsible for maximum hardness. The longer treatment time allows the nitrogen atoms to diffuse more to the surface, while the flake structure limits the absorption of nitrogen atoms into the surface of the cast iron. Characterization of Nodular Cast Iron shows that The hardening depth distribution trend due to the nitriding process in nodular cast iron was not much different from gray cast iron.
Besi cor kelabu, jenis cor ini sering dipakai karena memiliki banyak kelebihan. Kelebihan tersebut adalah mudah dituang atau dicor menjadi bentuk yang rumit, mudah dilakukan proses permesinan, tahan aus karena grafit dapat berfungsi sebagai pelumas, mempunyai kemampuan meredam getaran yang tinggi, mempunyai kekuatan tekan tinggi, sifat ketahan korosinya baik dibandingkan dengan baja konstruksi biasa, Spesimen yang sebelum proses diperoleh kekerasan tertiinggi yaitu 284,4 HV dengan kedalaman 30 μm, setelah diproses nitridisasi dengan temperature 6500C dengan holding 1,2, dan 3 jam, maka didapat kekerasan tertinggi sebesar 277,2 HV, 261,1 HV, 273,4 HV kekerasan naik pada holding 1 jam itu disebabkan karena reaksi kimia antara nitrogen dengan spesimen sehingga konsentrasi nitrogen pada permukaan spesimen yang berasal dari difusi nitrogen akan lebih banyak membentuk lapisan nitride. Pada pengujian spesimen dengan holding 1 jam didapat ketebalan lapisan 10, 20, 30, 40 μm dan permukaan tepi dari inti tidak merata sehingga lapisan menjadi tidak merata atau bergelombang, sedangkan pada temperatur 6500C dengan waktu 2 jam ketebalan ditunjukan hanya sampai pada 30 μm dan 40 μm, garis grafik mengalami kenaikan dikarenakan lapisan nitride dan permukaan tepi dari inti tidak merata sehingga lapisan menjadi bergelombang. Struktur mikro diperoleh dari hasil metalografi row material dan spesimen yang sesudah mengalami proses nitridisasi. Hasil dari struktur mikro sudah terlihat grafit berbentuk serpih keabu-abu an dan terlihat adanya sedikit korosi dikarenakan spesimen belum dilakukan proses
Prosperous sociaty in terms of livelihoods and having high income to fulfi ll all their needs are absolute desires, so they can avoid poverty, especially for people in rural areas whose lives depend on livestock farming, such as fi sh farmers. To avoid poverty, people need a program to be developed their knowledge and insight, with the aim of increasing their business income, as was done by a group of catfi sh farmers in Kampung Coban, Desa Kanigoro, Kecematan Pagelaran, Kabupaten Malang. Improving the knowledge and insight refered to solve their problems faced, namely the high of production and long harvest period; lack of knowledge and skills on how to select superior seeds and seedlings; and the lack of knowledge and skills in profi table business management. The program activities used social interactive methods in the form of coaching or mentoring and designing their own feed making tools. Based on the results of the activities of using tools and guidance, the catfi sh farmers can make their own feed mixed with factory feed, and increase the income.
<p><span style="font-size: medium;"><span style="font-family: Times New Roman;">The purpose of this paper is to analyze the dimensions and variables of National Innovation Capability. The findings in this paper are to refine the National Innovation Capabilities Dimension model developed by Chang and Lin (2012) by integrating a Network Dimension of Innovation. This paper analyzes the dimensions and variables of National Innovation Capability through a system approach that includes Input Sub System, Process Sub System, and Output Sub System. Network Dimensions Innovation is an integral part of the National Innovation Capabilities Dimension. This dimension is an important part, because the National Innovation Capability will largely depend on how innovative actors form networks and interact among them. The dimensions of National Innovation Capability are integrated into three sub system in a systems approach that includes input, process, and output. In the input consists of Dimensions of Innovation Resources. In the process consists of Innovation Demand Dimension, Innovation Network Dimension and Innovation Diffusion Dimension. In the output consists of Dimensions of Innovation Output. Each Dimension has some different variables. The entire dimensions and variables of these three sub system become unified as a Dimension and Variable of National Innovation Capability.</span></span></p><p> </p><strong>Keywords</strong>: National Innovation Capability, Dimensions, Variables, Sub Systems
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