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"The kinetics of isothermal phase transformation in tempered embrittlement stainless stell zeron-25 (SAF-2507): The kinetics study of phase transformation in stainless steel SAF 2507 heat-treated at 800,850 and 900 oC have been done.Eitheir observation of microstructure for treated materials by an optical or electron microscope confirmed the formation of carbide phase at grain boundaries between ferrite and austenite lead to three phase materials.It is furthur observed that for the three treated tempereture there were no significant change in volume fraction of territe phase found and thus it may be be assumed constant..Hovewer,this was not the case for two other phase in wich volume fraction of carbide phase show an increase and followed by a decrease in in volume fraction of austenite phase.It is then concluded that the carbide transformed from austenite.The number of volume fraction of carbide phase determinet by XRD methods were ranged from 6.0%to20% depends on time andtemperature of treatments.An avrami equation for kinetic sudy of phase transformation weresuccessively used for construction of phase transformation curves from which some kineticparameters of phase transformation were succesfully derived,among them the avarage constantrate reaction(n) equals to about one,the activation energy below 850oC is 304 and for 850oC above is 307 kj/mol.With kinetics constans above,the complete IT diagram for iso embrittlement of stainless steel SAF 2507 was succesfully built theoretically."

"Telah dilakukan pengamatan transformasi fasa pada sistem besi-karbon (Fe-C) melalui pengamatan penganalisa perubah panas (Differential Thermal Analyzer, DTA). Sampel Fe-C dipersiapkan dengan metode metalurgi serbuk menggunakan serbuk besi dan karbon murni (> 99 %), meliputi komposisi nominal paduan karbon rendah (0,1 wt.%), hypoeutectoid (0,4 wt.%), dan eutectoid (0,8 wt.%). Hasil pengukuran DTA dalam jangkau temperatur antara 25 0C-1100 0C menunjukkan bahwa pada sampel Fe murni diamati dua temperatur transisi endotermik masing-masing pada 773,8 0C berkaitan dengan transformasi feromagnet (α) menjadi paramagnet (β) dan pada temperatur 930 0C berkaitan dengan transformasi fasa β menjadi fasa austenit (γ). Kedua temperatur transisi ini juga secara konsisten teramati untuk kesemua sampel Fe-C yang dipelajari, namun dengan penambahan satu temperatur transisi sekitar 753 0C. Temperatur transisi tambahan ini berasal dari transformasi fasa pearlit menjadi austenit. Data pengukuran perubahan panas dalam jangkau temperatur 25 0C-1100 0C digunakan untuk menentukan nilai kapasitas panas, Cp sampel untuk jangkau temperatur tersebut. Hasil regresi polinomial terhadap kurva Cp sebagai fungsi T menghasilkan koefi sien regresi yang cukup baik berkisar di antara 0,8 dan 1,0.

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Phase Transformation Studies of Fe-C System with Differential Thermal Analyzer: Phase transformation studies for ironcarbon (Fe-C) system have been done by means of Differential Thermal Analyzer, DTA. Fe-C samples of nominal compositions for respectively low carbon containing alloy (0.1 wt.%), hypo eutectoid (0.4 wt.%), and eutectoid (0.8 wt.%) were prepared by powder metallurgy process using pure Fe and C powder materials (>99 %) as the feed stock. Measurement by DTA in the temperature range 25 oC?1100 oC for the samples indicated that there are two endothermic temperatures transition in pure Fe sample respectively at 773.8 oC associated with phase transformation of ferromagnetic (α) to paramagnetic (β) and at 930 oC due to a phase transformation of β-ferrite to austenite (γ). The two transition temperature was also consistently observed in all Fe-C samples but with one additional temperature transition at about 753 oC associated with a phase transformation of pearlite to austenite. Data of heat change measurement in the temperature range 25 oC-1100 oC were subsequently used for determination of heat capacity, Cp for the Fe-C samples as the function of T. Cp (T) curves when fi tted by polynomial regression have resulted in regression coeffi cients between 0.8 and 1.0."

"Skripsi ini membahas tentang pencarian pola sekuensial (sequential patterns) dengan menggunakan algoritma AprioriAll. Pencarian pola sekuensial melalui lima fase yaitu sort phase, litemset phase, transformation phase, sequence phase, dan maximal phase [AGR95]. Algoritma AprioriAll diterapkan pada sequence phase. Hasil penerapan berupa perangkat lunak yang dibuat dalam bahasa C++ dan menjadi bagian dari FIKUI Mining [RAS08].

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This essay discusses mining sequential pattern using AprioriAll algorithm. Mining sequential pattern through five phases, namely sort phase, litemset phase, transformation phase, sequence phase, and maximal phase [AGR95]. AprioriAll algorithm applied in sequence phase. Results include the implementation of the software created in C + + language and become part of FIKUI Mining software [RAS08]."