Model Change Bulletin              
              
                                   MCB#1                  February 19, 1991

                            TSCREEN (dated 91011)



     This Model Change Bulletin essentially initiates the activities of the
SCRAM BBS for this model.

      The TSCREEN model code, supporting programs and user's guide are
available from this bulletin board and complete documentation will be
available from the National Technical Information Service about March 1,
1990. An ALERT will be posted to SCRAM BBS when the NTIS documentation is
ready. For further details, read the README file that is part of the TSCRNnn
archival files that have been uploaded to the Screening Models section of
the SCRAM BBS.

     This model will henceforth be identified by its name, Julian date, and
a MCB #, i.e.: TSCREEN (dated 91011), MCB #1. Future changes to this model
will be identified by an updated Julian date found on the first line of the
model source code and followed by a reference to a SCRAM BBS Model Change
Bulletin (MCB#n) which will explain the nature and contents of the changes.
All Model Change Bulletins for this model will always be available for back
reference on this BBS. In the future, notification of changes (MCBs) to this
model will be made in the SCRAM ALERTS section of this BBS immediately
following the LOGON procedure.

     The source code for this model has been compiled and tested on an IBM
PC/AT compatible using Microsoft BASIC 7.0, and Microsoft C version 5.1. A
math coprocessor chip was installed in the PC.  The program requires 500
kilobytes (Kb) of free Random Access Memory (RAM).  The TSCREEN program
executable files occupy about 1 megabyte (MB) of disk space.  

                             ******************
                             * Important Note *
                             ******************

     New Model Change Bulletins will ONLY be issued when there is a change
to the source code for this model. Changes to test cases and/or any pre and
post processors that are included in the archival file for this model will
be addressed and appropriately identified in an amendment to the model's
latest MCB with notification posted in the SCRAM ALERTS section of the BBS. 


                          ************************
                          *                      *
                          *     Amendment #1     *
                          *                      *
                          *   February 19, 1991  *
                          *                      *
                          ************************


     Programming errors were discovered in the BASIC source codes files,
CHEMBASE.BAS and CHEMMENU.BAS, which are an accessory program and subroutine
to the TSCREEN model, respectively.  These two BASIC source codes were
corrected and compiled into an executable code, CHEMBASE.EXE.  All three files
have been uploaded to SCRAM BBS and now reside in the archival files
TSCN01.ARC, which contains the source codes, and TSCN03.ARC, which contains
the executable code.  TSCN01.ARC does not have to be downloaded in order to
run TSCREEN.  In addition, the HELPnnn.PCX files have been deleted from
TSCRN01.ARC since they are available as text files in TSCRN01.ARC or as a
compiled file, TSCREEN.PCL, in TSCRN04.ARC.