Continually rising energy prices have inspired increased interest in weight reduction in the automotive and aerospace industries, opening the door for the widespread use and development of lightweight structural materials. Chief among these materials are cast Al-Si and magnesium-based alloys. Utilization of Al-Si alloys depends on obtaining a modified fibrous microstructure in lieu of the intrinsic flake structure, a process which is incompletely understood. The local solidification conditions, mechanisms, and tensile properties associated with the flake to fiber growth mode transition in Al-Si eutectic alloys are investigated here using bridgman type gradient-zone directional solidification. Resulting microstructures are examined through quantitative image analysis of two-dimensional sections and observation of deep-etched sections showing three-dimensional microstructural features. The transition was found to occur in two stages: an initial stage dominated by in-plane plate breakup and rod formation within the plane of the plate, and a second stage where the onset of out-of-plane silicon rod growth leads to the formation of an irregular fibrous structure. Several microstructural parameters were investigated in an attempt to quantify this transition, and it was found that the particle aspect ratio is effective in objectively identifying the onset and completion velocity of the flake to fiber transition. The appearance of intricate out-of-plane silicon instability formations was investigated by adapting a perturbed-interface stability analysis to the Al-Si system. Measurements of silicon equilibrium shape particles provided an estimate of the anisotropy of the solid Si/liquid Al-Si system and incorporation of this silicon anisotropy into the model was found to improve prediction of the instability length scale. Magnesium alloys share many of the benefits of Al-Si alloys, with the added benefit of a 1/3 lower density and increased machinability. Magnesium castings often contain additions of heavier elements, such as zinc, zirconium, and rare earth elements, which significantly improve high temperature performance. However, additions of these elements can lead to macrosegregational effects in castings, which are detectable by radiographic scans. The effect of these flow-line indications on alloy mechanical properties is not well quantified. An examination of these flow-line indications and their effects on mechanical properties in three magnesium-based casting alloys was performed here in order to determine the best practice for dealing with affected castings. Preliminary results suggest the flow-lines do not measurably impact bulk material properties. Three additional methods of characterizing three-dimensional material structures are also presented: a minimum spanning tree analysis is utilized to quantify local structure in Cu-Zr liquid phase simulations obtained from molecular dynamics; the radial distribution function is applied to directionally solidified Al-Si structures in an attempt to extract local spacing data; and the critical diameter measurement is also defined and applied to irregular eutectic Al-Si structures.
Originally posted by Damian1978
15.03.2011 - I have found this revelation lightly related with another news. It's exactly the same day when the Facebook is supposed to be close. Could be just a rumour or maybe the CEO of Facebook knows more than us.
I have attached the link with this information below :
All the Best Comrades !!!
Originally posted by curious7
reply to post by Damian1978
Facebook to close March 15th? Not sure I believe that but I've seen that date in relation to a possible few happenings in various prediction and conspiracy threads around here for a few months.
As agreed to with EPA in the 200 Area Unit Managers Meeting Groundwater Operable Unit Status (FH-0503130), the baseline risk assessment (BRA) was delayed from inclusion in the remedial investigation (RI) report and is completed and documented in this FS. The Remedial Investigation Report for 200-ZP-1 Groundwater Operable Unit (referred to as the 200-ZP-1 RI report) (DOE/RL-2006-24) included an evaluation of human health and ecological risks and hazards. The RI report identified the radiological and chemical contaminants of potential concern (COPCs) that represent the primary risks to human health and the environment. The complete risk assessment in this FS incorporates additional analytical data from the unconfined aquifer that were obtained during or after preparation of the RI report, particularly for carbon tetrachloride and technetium-99. This FS also includes the initial results from an ongoing study of technetium-99 contamination near WMA-T, the sampling of new wells near the 216-W-LC laundry waste crib and T Plant, updated Hanford vadose zone fate and transport modeling, and groundwater particle-tracking analysis. The purpose of this FS is to develop and evaluate alternatives for remediation of the groundwater in the 200-ZP-1 OU. The alternatives considered provide a range of potential response actions (i.e., no action; institutional controls and monitored natural attenuation [MNA]; and pump-and-treat with MNA, flow-path control, and institutional controls) that are appropriate to address site-specific conditions.
Originally posted by coolottie
reply to post by gr82m8okdok
Can you give the link for the info on the World Trade Center?
SEARCH THIS LINK AND PUT IN "THROUGH THE LOOKING GLASS" I feel like I fell down the rabbit hole!
Originally posted by Jophiel
Originally posted by Towloc
I don't know if anyone else has come across this yet, I have found some articles that say they were published months in the future on this website
theres a link to one.
that article came up when I typed in population control and its publish date is march 14 2011
did anyone else see this
wtf is this about???????????
this needs its own thread!!!!!!!!!!!!!!!!!edit on 5-2-2011 by Jophiel because: (no reason given)
Subject N70100* --Physics--Controlled Thermonuclear Research-- Confinement & Heating; CYCLOTRON FREQUENCY; ELECTRONS; HEATING; HOMOGENEOUS PLASMA; IONS; LANGMUIR FREQUENCY; MICROWAVE RADIATION; PLASMA; PLASMA SIMULATION