According to moore and marra's (2005) case study, which observed two online courses, students in the first course implemented a constructive argumentation approach while students in second course had less structure for their postings. as they stated, when instructors create online discussion board activities, they must answer at least two questions. these questions are: "what is the objective of the discussions? " and "how important are online discussions in comparison to the other activities that students will perform? " according to their findings, the discussion activities that were designed based on the answers to these questions can influence the quality and quantity of interactions (moore & marra, 2005).

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

Asteam is contained in a rigid tank with a volume of 1 m3. initially, the pressure and temperature are 7 bar and 500 oc, respectively. the temperature drops due to cooling process. determine: (1) the temperature at which condensation begins in °c, (2) the fraction of the total mass that has condensed when the pressure decreased to 0.5 bar. (3) the volume in m3 occupied by saturated liquid at the final state?

Ashielded metal arc-welding operation is accomplished in a work cell by a fitter and a welder. the fitter takes 5.5 min to load components into the welding fixture at the beginning of the work cycle, and 1.5 min to unload the completed weldment at the end of the cycle. the total ength of the weld seams 1200 mm, and the travel speed used by the welder averages 300 mm/min. every 600 mm of seam length, the welding stick must be changed, which takes 0.8 min. while the fitter is working, the welder is idle (resting): and while the welder is working the fitter is idle. (a) determine the average arc-on time as a fraction of the work cycle time. (b) how much improvement in arc-on time would result if the welder used flux-cored arc welding (manually operated), given that the spool of weld wire must be changed every 10 weldments, and it takes the welder 5.0 min to accomplish the change? (c) what are the production rates for these two cases (weldments completed per hour)? attach your work and solutions.