1
                                                                  Exhibit 4.27



                             WARRANT CERTIFICATE



THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED ("ACT"), AND MAY NOT BE OFFERED OR SOLD
EXCEPT PURSUANT TO (I) AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT, (II)
TO THE EXTENT APPLICABLE, RULE 144 UNDER THE ACT (OR ANY SIMILAR RULE UNDER
SUCH ACT RELATING TO THE DISPOSITION OF SECURITIES) OR (III) AN OPINION OF
COUNSEL, IF SUCH OPINION SHALL BE REASONABLY SATISFACTORY TO COUNSEL TO THE
ISSUER, THAT AN EXEMPTION FROM REGISTRATION UNDER SUCH ACT IS AVAILABLE.

TRANSFER OR EXCHANGE OF THE WARRANTS REPRESENTED BY THIS CERTIFICATE IS
RESTRICTED IN ACCORDANCE WITH THE WARRANT AGREEMENT REFERRED TO HEREIN.

                           EXERCISABLE ON OR BEFORE
                    5:30 P.M., DENVER TIME, March 11, 1998

No. W-1993A                                                     50,000 Warrants


                             WARRANT CERTIFICATE


        This Warrant Certificate certifies that Alfred Schechter, or
registered assigns, is the registered holder of 50,000 Warrants to purchase
initially, at any time from March 12, 1993 until 5:30 p.m. Denver time on
March 11, 1998 ("Expiration Date"), up to 50,000 shares of Class A voting
common stock, $.01 par value ("Common Stock") of CRYENCO SCIENCES, INC., a
Delaware corporation (the "Company"), at the price per share of Common Stock
equal to the Exercise Price set forth in the Warrant Agreement dated as of
March 12, 1993 between the Company and Alfred Schechter (the "Warrant
Agreement"), upon surrender of this Warrant Certificate and payment of the
Exercise Price at an office or agency of the Company, but subject to the
conditions set forth herein and in the Warrant Agreement. Payment of the
Exercise Price shall be made by certified or official bank cashier's check
payable to the order of the Company; PROVIDED, HOWEVER, that the holder hereof
shall have the right, at his or its election, in lieu of delivering the
Exercise Price in cash, to instruct the Company in the form of subscription to
retain, in payment of the Exercise Price, a number of shares of Common Stock
(the "Payment Shares") equal to the quotient of (i) the Exercise Price
multiplied by the number of shares as to which this Warrant is then being
exercised divided by (ii) the "Average Closing Price" as of the date of
exercise and to deduct the number of Payment Shares from the shares to be
delivered to 
   2



the holder hereof. "Average Closing Price" means, as of any date, (x) if shares
of Common Stock are listed on a national securities exchange, the average of the
closing sales prices therefor on the largest securities exchange on which such
shares are traded on the last ten (10) trading days before such date, (y) if
such shares are listed on the NASDAQ National Market System but not on any
national securities exchange, the average of the closing sales prices therefor
on the NASDAQ National Market System on the last ten (10) trading days before
the date of the exercise of the Warrants or (z) if such shares are not listed on
either a national securities exchange or the NASDAQ National Market System, the
average of the sales prices therefor on the last twenty (20) trading days before
the date of the exercise of the Warrants.

        No Warrant may be exercised after 5:30 p.m., Denver time, on the
Expiration Date, at which time all Warrants evidenced hereby, unless exercised
prior thereto, hereby shall thereafter be void.

        The Warrants evidenced by this Warrant Certificate are part of a duly
authorized issue of Warrants issued pursuant to the Warrant Agreement, which is
hereby incorporated by reference in and made a part of this instrument and is
hereby referred to for a description of the rights, limitation of rights,
obligations, duties and immunities thereunder of the Company and the holders
(the words "holders or "holder" meaning the registered holders or registered
holder) of the Warrants.

        The Warrant Agreement provides that upon the occurrence of certain
events the Exercise Price and the type and/or number of the Company's securities
issuable thereupon may, subject to certain conditions, be adjusted. In such
event, the Company will, at the request of the holder, issue a new Warrant
Certificate evidencing the adjustment in the Exercise Price and the number
and/or type of securities issuable upon the exercise of the Warrants; provided,
however, that the failure of the Company to issue such new Warrant Certificates
shall not in any way change, alter, or otherwise impair, the rights of the
holder as set forth in the Warrant Agreement to purchase the number of shares
for the exercise price as so adjusted or any other rights set forth in the
Warrant Agreement.

        Upon due presentment for registration of transfer of this Warrant
Certificate at an office or agency of the Company, a new Warrant Certificate or
Warrant Certificates of like tenor and evidencing in the aggregate a like number
of Warrants shall be issued to the transferee(s) in exchange for this Warrant
Certificate, subject to the limitations provided herein and in the Warrant
Agreement, without any charge except for any tax or other governmental charge
imposed in connection with such transfer.



                                      -2-
   3


        Upon the exercise of less than all of the Warrants evidenced by this
Certificate, the Company shall forthwith issue to the holder hereof a new
Warrant Certificate representing such unexercised Warrants.

        The Company may deem and treat the registered holder(s) hereof as the
absolute owner(s) of this Warrant Certificate (notwithstanding any notation of
ownership or other writing hereon made by anyone), for the purpose of any
exercise hereof , and of any distribution to the holder(s) hereof, and for all
other purposes, and the Company shall not be affected by any notice to the
contrary.

        All terms used in this Warrant Certificate which are defined in the
Warrant Agreement shall have the meanings assigned to them in the Warrant
Agreement.


        IN WITNESS WHEREOF, the Company has caused this Warrant Certificate to
be duly executed under its corporate seal.

Dated as of March 12, 1993

                                                 CRYENCO SCIENCES, INC.


[SEAL]                                           By: /s/ Don M. Harwell
                                                    ----------------------------
                                                    Name:   Don M. Harwell
                                                    Title:  Vice President


Attest:


/s/ Alison A. Murray
- ------------------------
Name:   Alison A. Murray
Title:  Secretary







                                      -3-