The technique therefore has widespread applicability and has been used successfully in commercial EDXS systems for more than 25 years.
This observation was exploited in the popular "FRAME" public domain software where measurements at two background energies were used to determine [K.sub.1] and [K.sub.2] (12) and this has also been adopted in some commercial EDXS systems.
Most EDXS systems are fitted with pile up inspectors that are fast and effective for high energy photons.
Stored experimental profiles effectively characterise the energy response of a particular detector but suitable standards are not always available for every element and profiles also have to be obtained for all the EDXS configurations that are to be used.
A much more common and serious problem for EDXS is the case of overlapping peaks.
For EDXS systems without an automatic zero measurement, calibration requires a spectrum with two well defined x-ray peaks of similar area, usually AlK[alpha] and CuK[alpha] at 1.49 keV and 8.04 keV.
While edX hopes to attract many students to its online offerings, it also promotes the campus as a place of learning.
Blended classrooms are growing in appeal, and, according to Johannes Heinlein, they represent the future for edX (pers.
Positive results are emerging out of blended and flipped classrooms, such as the edX pilot program at San Jose State University (not to be confused with the Udacity-San Jose State pilot program).
EdX has other SPOC (small private online course) pilot programs featuring the blended model at MassBay Community College and Bunker Hill Community College.
HarvardX, the university's operating entity for the edX initiative, is in the process of constructing new video facilities and hiring production staff such as course-development managers, media mangers, and video managers (Lue 2013).
When asked if edX had any plans to start organizing formal meet-ups for its course offerings, Howard Lurie stated that it is good that these meet-ups happen without edX involvement; edX does not want to presume to know how people in Thailand or Brazil might best study (pers.