Development of Ultra-Carbon Steel Prepared by Mechanical Alloying and Subsequent Hot Pressing

It is known that the most effective way to improve mechanical properties of steels is by microstructural refinement. Iron and graphite powders mixture with hypoeutectoid composition were mechanically alloyed (MAed) and subsequently hot pressed (HPed) to provide steels with fine structure. Mechanical Alloying (MA) was carried out using a planetary ball mill for 100, 200 and 300 h, while HP at 41 MPa at various temperatures: 610ºC (below), 730ºC (near) and 800ºC (above the eutectoid transformation point A1). The mechanically alloyed (MAed) powders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). While, the HPed compacts were characterized by SEM, Vickers hardness and tensile test. During MA, refinement of crystallite, formations of super-saturated iron solid solution and Fe/C amorphous phase occured first. With further MA time, these phases might begin to transform to more stable phases such as carbides. In the case of HP at 610ºC (below A1), very fine cementites were precipitated in fine ferrite grain with sub-micron meter in the size. However, the mechanical properties cannot be attained because of low sinterability. At 730ºC (near A1), the strength reaches the maximum value. With further temperature increase (at 800ºC), the sintering progressed well and the coarsening occured, resulting the decrease in strength. However, the fracture strain increased significantly. The steels obtained in the present study had mechanical properties comparable to those of standard (JIS) steels through the welle stablished heat treatment such as normalizing and thermal refining

Analisa Pengaruh Pengendalian Kinerja Proyek Terhadap Mutu Proyek Konstruksi Dengan Menggunakan Uji Statistika

In the construction project planning and controlling is the most basic function in realizing the success of an activity in construction project. A success a project cannot be separated by a series of activities which is included the stages of planning, implementation and controlling. Controlling, monitoring and performance measurement needs to be done as to determine whether there are deviation in the work implementation of what has been set. Then, in this case needs to be analyzed to know the effect of controlling project performance indicators (Occupational Safety and Health, Cost and Time) toward the quality of construction project.The result of the research shows there is simultaneously a positive and significant influence between the variables of Occupational Safety and Health (X1), a Cost variable (X2) and a Time variable (X3) simultaneously toward Quality (Y1) is showed the value Fcount (25.755) is larger than Ftable (2.71) with significance level of 0.000 is smaller than sig. (α) of 0.05.For the partial variable of Occupational Safety and Health (X1) indicates tcount amounted to 3.672 with significance level amount of 0.000 is larger than ttable 1.98667 and a percentage of (37%), a cost variable (X2) indicates tcount amounted to 1.705 with significance level amount of 0.092 is smaller than ttable 1.98667 and a percentage of (17%), and a time variable (X3) is showed value of tcount amounted to 1.705 with significance level amount of 0.334 is smaller than ttable 1.98667 and a percentage amount of (17%)

Pengaruh Pemaparan Medan Magnet Pada Media Mandels Yang Dimodifikasi Terhadap Pertumbuhan Dan Aktivitas Enzim Selulase Bacillus SP.

Enzymes can undergo structural changes due to various environmental factor such as pH,temperature, electricity and magnetic fields. The purpose of this study was to investigate theeffect of magnetic field strength and duration of exposure to the modified of media Mandelsused as a culture medium of Bacillus sp. on the growth and activity of cellulase enzyme fromthe bacterium Bacillus sp. Factorial study group were prepared using the method of fullrandomized design (RKLT). The first factor is the strong magnetic field consists of 4 levels ofmagnetic field strength treatment: 0 mT; 0,1 mT; 0,2 mT; 0.3 mT. The second faktor is theprolonged exposure consisting of 4 levels prolonged exposure treatments 0, 10, 20, 30minutes. each unit treatment was repeated 3 times. The results showed that exposure tomagnetic fields on modified of media Mandels causes a decrease in the relative activity ofthe enzyme cellulase and relative growth of Bacillus sp

Propagation of nuclear data uncertainties for ELECTRA burn-up calculations

The European Lead-Cooled Training Reactor (ELECTRA) has been proposed as a training reactor for fast systems within the Swedish nuclear program. It is a low-power fast reactor cooled by pure liquid lead. In this work, we propagate the uncertainties in Pu-239 transport data to uncertainties in the fuel inventory of ELECTRA during the reactor life using the Total Monte Carlo approach (TMC). Within the TENDL project the nuclear models input parameters were randomized within their uncertainties and 740 Pu-239 nuclear data libraries were generated. These libraries are used as inputs to reactor codes, in our case SERPENT, to perform uncertainty analysis of nuclear reactor inventory during burn-up. The uncertainty in the inventory determines uncertainties in: the long-term radio-toxicity, the decay heat, the evolution of reactivity parameters, gas pressure and volatile fission product content. In this work, a methodology called fast TMC is utilized, which reduces the overall calculation time. The uncertainty in the long-term radiotoxicity, decay heat, gas pressure and volatile fission products were found to be insignificant. However, the uncertainty of some minor actinides were observed to be rather large and therefore their impact on multiple recycling should be investigated further. It was also found that, criticality benchmarks can be used to reduce inventory uncertainties due to nuclear data. Further studies are needed to include fission yield uncertainties, more isotopes, and a larger set of benchmarks.Comment: 4 pages, 4 figures, Proc. 2013 International Conference on Nuclear Data for Science & Technology (ND2013), March 4-8, 2013, New York, USA, to be published in Nuclear Data Sheet