Exhibit 10.84

                           ACQUISITION PROMISSORY NOTE

$2,000,000.00                                                  Fairfax, Virginia
                                                                  April 30, 1997

     FOR VALUE RECEIVED, VERSAR, INC., a corporation organized under the laws of
the State of Delaware and GEOMET  TECHNOLOGIES,  INC., a  corporation  organized
under the laws of the State of Delaware (collectively,  the "Borrowers" and each
a "Borrower"), jointly and severally promise to pay to the order of NATIONSBANK,
N.A., a national banking association, its successors and assigns (the "Lender"),
the  principal  sum of TWO  MILLION  AND  NO/100  DOLLARS  ($2,000,000.00)  (the
"Principal  Sum"),   together  with  interest  thereon  at  the  rate  or  rates
hereinafter provided, in accordance with the following:

1.   Interest.  Commencing as of the date hereof and continuing  until repayment
in full of all sums due hereunder,  the unpaid Principal Sum shall bear interest
at the fluctuating  per annum interest rate  established by the Lender from time
to time,  at its  discretion,  whether or not such rate is  otherwise  published
("Prime Rate"), plus one half of one percent (.50%) per annum. The Prime Rate is
established  by the Lender as an index or base and may or may not be the best or
lowest  rate  charged by the Lender on any loan.  The rate of  interest  charged
under this Note shall change immediately and  contemporaneously  with any change
in the Prime Rate.  All interest  payable  under the terms of this Note shall be
calculated on the basis of a 360-day year and the actual number of days elapsed.

2.   Payments and Maturity.  The unpaid  Principal  Sum,  together with interest
thereon at the rate or rates provided above, shall be payable as follows:

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     (a) Interest on the unpaid  Principal Sum shall be due and payable monthly,
commencing  May 31,  1997,  and on the  last  day of each  month  thereafter  to
maturity; and

     (b)  The  unpaid  Principal  Sum  shall  be  due  and  payable  in  monthly
installments of principal in the amount of $41,666.67  each,  commencing May, 31
1997, and on the last day of each month to and including April 30, 1998; and

     (c) Commencing on May 31, 1998 and continuing on the last day of each month
thereafter until maturity,  the unpaid Principal Sum shall be due and payable in
monthly installments of principal in the amount of $62,500 each; and

     (d) Unless sooner paid, the entire unpaid Principal Sum,  together with all
interest accrued and unpaid thereon,  shall be due and payable in full on April,
30, 2000.

3.   Default  Interest.   Upon  the  occurrence  of  an  Event  of  Default  (as
hereinafter defined), the unpaid Principal Sum shall bear interest thereafter at
a rate (the "Default  Rate") two percent  (2.0%) per annum in excess of the then
current  rate or rates of  interest  hereunder  until  such  Event of Default is
cured.

4.   Late  Charges.  If the  Borrowers  shall fail to make any payment under the
terms of this Note within ten (10) days after the date such  payment is due, the
Borrowers  shall pay to the Lender on demand a late charge equal to five percent
(5%) of such payment.

5.   Application  and Place of Payments.  All payments,  made on account of this
Note  shall  be  applied  first  to the  payment  of any  late  charge  then due
hereunder,  second to the  payment  of  accrued  and  unpaid  interest  then due
hereunder,  and the remainder,  if any, shall be applied to the unpaid Principal
Sum,  with  application  first  made  to all  principal  installments  then  due
hereunder,  next to the outstanding  principal balance due and owing at maturity
and thereafter to the principal

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payments due in the inverse order of maturities.  Notwithstanding  any provision
contained herein to the contrary,  any portion of a permitted partial prepayment
applied to the unpaid  Principal Sum shall be applied  first to the  outstanding
principal  balance due and owing at maturity  and  thereafter  to the  principal
payments due in the inverse order of maturities. All payments on account of this
Note  shall  be  paid in  lawful  money  of the  United  States  of  America  in
immediately  available funds during regular  business hours of the Lender at its
principal  office in McLean,  Virginia  or at such other times and places as the
Lender  may at any  time and  from  time to time  designate  in  writing  to the
Borrowers. The Lender is authorized to deduct any payment (including payments of
principal and/or interest as above provided) from the Borrowers'  Account Number
__________ on or after the date the payment is due; provided, however, that such
authorization shall not be deemed to relieve the Borrowers from their obligation
to make such payment when it is due.

6.   Prepayment.  The Borrowers may prepay the Principal Sum in whole or in part
upon ten (10)  days  prior  written  notice to the  Lender  without  premium  or
penalty.

7.   Financing Agreement and Other Financing Documents.  This Note is one of the
"Acquisition  Notes" described in a Financing and Security Agreement dated March
31,  1997 by and among the  Borrowers  and the  Lender  (as  amended,  modified,
restated,  substituted,  extended and renewed at any time and from time to time,
the "Financing Agreement").  The indebtedness evidenced by this Note is included
within  the  meaning  of the term  "Obligations"  as  defined  in the  Financing
Agreement.  The term  "Financing  Documents"  as used in this  Note  shall  mean
collectively  this  Note,  the  Financing  Agreement  and any other  instrument,
agreement,  or document  previously,  simultaneously,  or hereafter executed and
delivered by the Borrowers  and/or any other person,  singularly or jointly with
any other person, evidencing, securing, guaranteeing, or in connection with

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the Principal Sum, this Note and/or the Financing Agreement.

8.   Security. This Note is secured as provided in the Financing Agreement.

9.   Events  of  Default.  The  occurrence  of any one or more of the  following
events shall constitute an event of default (individually, an "Event of Default"
and collectively, the "Events of Default") under the terms of this Note:

          (a) The failure of the  Borrowers to pay to the Lender within five (5)
     days of when due any and all amounts payable by the Borrowers to the Lender
     under the terms of this Note; or

          (b) The  occurrence of an event of default (as defined  therein) under
     the terms and conditions of any of the other Financing Documents.

10.  Remedies.  Upon the occurrence of an Event of Default, at the option of the
Lender,  all amounts  payable by the  Borrowers to the Lender under the terms of
this Note shall  immediately  become due and  payable  by the  Borrowers  to the
Lender without notice to the Borrowers or any other person, and the Lender shall
have all of the rights,  powers,  and remedies available under the terms of this
Note,  any of the  other  Financing  Documents  and  all  applicable  laws.  The
Borrowers and all endorsers, guarantors, and other parties who may now or in the
future be primarily or  secondarily  liable for the payment of the  indebtedness
evidenced by this Note hereby severally waive  presentment,  protest and demand,
notice of protest, notice of demand and of dishonor and non-payment of this Note
and expressly agree that this Note or any payment hereunder may be extended from
time to time without in any way affecting the joint and several liability of the
Borrowers, guarantors and endorsers.

     Until such time as the Lender is not committed to extend  further credit to
the  Borrowers  and all  Obligations  of the  Borrowers  to the Lender have been
indefeasibly paid in full in cash, and subject

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to and not in  limitation  of the  provisions  set  forth in the next  following
paragraph  below,  no  Borrower  shall  have any right of  subrogation  (whether
contractual,  arising under the Bankruptcy Code or otherwise),  reimbursement or
contribution  from any  Borrower,  or any guarantor nor any right of recourse to
its security for any of the debts and  obligations of any Borrower which are the
subject of this Note. Except as otherwise  expressly  permitted by the Financing
Agreement,  any and all present and future debts and obligations of any other to
any Borrower are hereby  subordinated to the full payment and performance of all
present and future debts and  obligations  to the Lender under this Note and the
Financing   Agreement   and  the   Financing   Documents,   provided,   however,
notwithstanding  anything set forth in this Note to the  contrary,  prior to the
occurrence  of a payment  Default,  the  Borrowers  shall be  permitted  to make
payments on account of any of such present and future debts and obligations from
time to time in accordance with the terms thereof.

     The Borrowers further agree that, if any payment made by the Borrowers,  or
any other person is applied to this Note and is at any time annulled, set aside,
rescinded,  invalidated,  declared to be fraudulent or preferential or otherwise
required to be refunded or repaid,  or the  proceeds of any  property  hereafter
securing  this Note is required  to be  returned by the Lender to any  Borrower,
their  estate,  trustee,  receiver  or  any  other  party,  including,   without
limitation,  such  Borrower,  under any  bankruptcy  law,  state or federal law,
common law or equitable cause, then, to the extent of such payment or repayment,
such Borrower's  liability  hereunder (and any lien,  security interest or other
collateral  securing  such  liability)  shall be and  remain  in full  force and
effect,  as fully as if such payment had never been made,  or, if prior  thereto
any such lien, security interest or other collateral hereafter securing such the
Borrower's  liability hereunder shall have been released or terminated by virtue
of such cancellation or surrender,  this Note (and such lien,  security interest
or other collateral) shall be

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reinstated in full force and effect,  and such prior  cancellation  or surrender
shall  not  diminish,   release,  discharge,  impair  or  otherwise  affect  the
obligations  of such  Borrower  of the  amount  of such  payment  (or any  lien,
security interest or other collateral securing such obligation).

     The JOINT AND SEVERAL obligations of each Borrower under this Note shall be
absolute,  irrevocable  and  unconditional  and shall  remain in full  force and
effect  until the  outstanding  principal  of and  interest on this Note and all
other Obligations or amounts due hereunder and under the Financing Agreement and
the Financing  Documents  shall have been  indefeasibly  paid in full in cash in
accordance with the terms thereof and this Note shall have been canceled.

11.  Expenses.  The  Borrowers  promise  to pay to the  Lender  on demand by the
Lender all costs and  expenses  incurred  by the Lender in  connection  with the
collection  and  enforcement  of  this  Note,  including,   without  limitation,
reasonable attorneys' fees and expenses and all court costs.

12.  Notices.  Any notice,  request,  or demand to or upon the  Borrowers or the
Lender  shall be deemed to have been  properly  given or made when  delivered in
accordance with Section 11.01 of the Financing Agreement.

13.  Miscellaneous.  Each right, power, and remedy of the Lender as provided for
in this  Note  or any of the  other  Financing  Documents,  or now or  hereafter
existing  under  any  applicable  law  or  otherwise  shall  be  cumulative  and
concurrent  and shall be in  addition  to every other  right,  power,  or remedy
provided  for in this Note or any of the  other  Financing  Documents  or now or
hereafter  existing under any  applicable  law, and the exercise or beginning of
the  exercise  by the  Lender  of any one or more of  such  rights,  powers,  or
remedies shall not preclude the  simultaneous or later exercise by the Lender of
any or all such other rights,  powers,  or remedies.  No failure or delay by the
Lender to insist upon the strict performance of any term,  condition,  covenant,
or agreement of this Note or

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any of the other Financing Documents, or to exercise any right, power, or remedy
consequent  upon a breach thereof,  shall  constitute a waiver of any such term,
condition,  covenant, or agreement or of any such breach, or preclude the Lender
from  exercising any such right,  power,  or remedy at a later time or times. By
accepting  payment  after the due date of any amount  payable under the terms of
this Note,  the Lender  shall not be deemed to waive the right either to require
prompt  payment when due of all other  amounts  payable  under the terms of this
Note or to declare an Event of Default  for the  failure to effect  such  prompt
payment of any such  other  amount.  No course of  dealing  or conduct  shall be
effective to amend,  modify,  waive,  release,  or change any provisions of this
Note.

14.  Partial Invalidity. In the event any provision of this Note (or any part of
any  provision)  is held by a court of  competent  jurisdiction  to be  invalid,
illegal,  or  unenforceable  in any respect,  such  invalidity,  illegality,  or
unenforceability  shall not affect any other provision (or remaining part of the
affected  provision)  of this Note;  but this Note shall be construed as if such
invalid,  illegal,  or  unenforceable  provision  (or part thereof) had not been
contained  in this  Note,  but only to the  extent it is  invalid,  illegal,  or
unenforceable.

15.  Captions.  The captions herein set forth are for convenience only and shall
not be deemed to define, limit, or describe the scope or intent of this Note.

16.  Applicable Law. The Borrowers acknowledge and agree that this Note shall be
governed  by the laws of the  Commonwealth  of  Virginia,  even  though  for the
convenience  and at the  request  of the  Borrowers,  this Note may be  executed
elsewhere.


17.  WAIVER OF TRIAL BY JURY.  THE  BORROWERS  HEREBY WAIVE TRIAL BY JURY IN ANY
ACTION OR PROCEEDING TO WHICH ANY BORROWER

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AND THE LENDER MAY BE PARTIES,  ARISING OUT OF OR IN ANY WAY  PERTAINING  TO (A)
THIS NOTE OR (B) THE FINANCING DOCUMENTS.  IT IS AGREED AND UNDERSTOOD THAT THIS
WAIVER  CONSTITUTES A WAIVER OF TRIAL BY JURY OF ALL CLAIMS  AGAINST ALL PARTIES
TO SUCH ACTIONS OR  PROCEEDINGS,  INCLUDING  CLAIMS AGAINST  PARTIES WHO ARE NOT
PARTIES TO THIS NOTE.

     THIS WAIVER IS KNOWINGLY,  WILLINGLY AND VOLUNTARILY MADE BY EACH BORROWER,
AND EACH BORROWER HEREBY REPRESENTS THAT NO  REPRESENTATIONS  OF FACT OR OPINION
HAVE BEEN MADE BY ANY INDIVIDUAL TO INDUCE THIS WAIVER OF TRIAL BY JURY OR TO IN
ANY WAY MODIFY OR NULLIFY ITS EFFECT.  EACH BORROWER FURTHER  REPRESENTS THAT IT
HAS BEEN  REPRESENTED  IN THE  SIGNING  OF THIS  NOTE AND IN THE  MAKING OF THIS
WAIVER BY INDEPENDENT LEGAL COUNSEL,  SELECTED OF ITS OWN FREE WILL, AND THAT IT
HAS HAD THE OPPORTUNITY TO DISCUSS THIS WAIVER WITH COUNSEL.

18.  ARBITRATION.  ANY  CONTROVERSY OR CLAIM BETWEEN OR AMONG THE PARTIES HERETO
INCLUDING  BUT NOT  LIMITED  TO THOSE  ARISING  OUT OF THIS NOTE OR ANY  RELATED
INSTRUMENTS,  AGREEMENTS OR  DOCUMENTS,  INCLUDING ANY CLAIM BASED ON OR ARISING
FROM AN ALLEGED TORT,  SHALL BE DETERMINED BY BINDING  ARBITRATION IN ACCORDANCE
WITH THE FEDERAL  ARBITRATION  ACT (OR IF NOT APPLICABLE,  THE APPLICABLE  STATE
LAW), THE RULES OF PRACTICE AND PROCEDURE FOR ARBITRATION OF COMMERCIAL

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DISPUTES OF  ENDISPUTE,  INC.,  D/B/A  J.A.M.S./ENDISPUTE  ("J.A.M.S.")  AND THE
"SPECIAL RULES" SET FORTH BELOW. IN THE EVENT OF AN  INCONSISTENCY,  THE SPECIAL
RULES SHALL CONTROL.  JUDGMENT UPON ANY ARBITRATION  AWARD MAY BE ENTERED IN ANY
COURT HAVING JURISDICTION.  ANY PARTY TO THIS INSTRUMENT,  AGREEMENT OR DOCUMENT
MAY BRING ANY ACTION,  INCLUDING A SUMMARY OR  EXPEDITED  PROCEEDING,  TO COMPEL
ARBITRATION OF ANY  CONTROVERSY OR CLAIM TO WHICH THIS NOTE RELATES IN ANY COURT
HAVING JURISDICTION OVER SUCH ACTION.

     (A) SPECIAL RULES.  THE  ARBITRATION  SHALL BE CONDUCTED IN FAIRFAX COUNTY,
VIRGINIA  AND  ADMINISTERED  BY  J.A.M.S.  WHO WILL  APPOINT AN  ARBITRATOR.  IF
J.A.M.S. IS UNABLE OR LEGALLY PRECLUDED FROM ADMINISTERING THE ARBITRATION, THEN
THE AMERICAN  ARBITRATION  ASSOCIATION WILL SERVE. ALL ARBITRATION HEARINGS WILL
BE COMMENCED WITHIN NINETY (90) DAYS OF THE DEMAND FOR ARBITRATION; FURTHER, THE
ARBITRATOR  SHALL  ONLY,  UPON A SHOWING OF CAUSE,  BE  PERMITTED  TO EXTEND THE
COMMENCING OF SUCH HEARING FOR AN ADDITIONAL SIXTY (60) DAYS.

     (B)  RESERVATION  OF  RIGHTS.  NOTHING IN THIS NOTE SHALL BE DEEMED TO: (I)
LIMIT THE  APPLICABILITY OF ANY OTHERWISE  APPLICABLE  STATUTES OF LIMITATION OR
REPOSE AND ANY WAIVERS CONTAINED IN THIS INSTRUMENT,  AGREEMENT OR DOCUMENT;  OR
(II) BE A WAIVER BY THE  LENDER OF THE  PROTECTION  AFFORDED  TO IT BY 12 U.S.C.
ss.91 OR ANY SUBSTANTIALLY

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EQUIVALENT  STATE LAW; OR (III)  LIMIT THE RIGHT OF THE LENDER:  (A) TO EXERCISE
SELF HELP  REMEDIES  SUCH AS (BUT NOT LIMITED  TO) SET OFF, OR (B) TO  FORECLOSE
AGAINST ANY REAL OR PERSONAL PROPERTY COLLATERAL,  OR (C) TO OBTAIN FROM A COURT
PROVISIONAL  OR  ANCILLARY  REMEDIES  SUCH AS (BUT NOT  LIMITED  TO)  INJUNCTIVE
RELIEF,  WRIT OF POSSESSION  OR THE  APPOINTMENT  OF A RECEIVER.  THE LENDER MAY
EXERCISE SUCH SELF HELP RIGHTS,  FORECLOSE  UPON SUCH  PROPERTY,  OR OBTAIN SUCH
PROVISIONAL OR ANCILLARY  REMEDIES  BEFORE,  DURING OR AFTER THE PENDENCY OF ANY
ARBITRATION  PROCEEDING  BROUGHT  PURSUANT  TO  THIS  INSTRUMENT,  AGREEMENT  OR
DOCUMENT.  NEITHER THE  EXERCISE OF SELF HELP  REMEDIES NOR THE  INSTITUTION  OR
MAINTENANCE  OF ANY ACTION  FOR  FORECLOSURE  OR FOR  PROVISIONAL  OR  ANCILLARY
REMEDIES  SHALL  CONSTITUTE  A WAIVER OF THE RIGHT OF ANY PARTY,  INCLUDING  THE
CLAIMANT IN SUCH ACTION,  TO ARBITRATE  THE MERITS OF THE  CONTROVERSY  OR CLAIM
OCCASIONING RESORT TO SUCH REMEDIES.

19.  Expenses.  The  Borrowers  promise  to pay to the  Lender  on demand by the
Lender all costs and  expenses  incurred  by the Lender in  connection  with the
collection  and  enforcement  of  this  Note,  including,   without  limitation,
reasonable attorneys' fees and expenses and all court costs.

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     IN WITNESS  WHEREOF,  the  Borrowers  have  caused this Note to be executed
under seal by their duly authorized officers as of the date first written above.

WITNESS OR ATTEST:             VERSAR, INC.


/s/ Lula Fasold                By: /s/ Lawrence W. Sinnott            (SEAL)
--------------------------         --------------------------
                                   Name:  Lawrence W. Sinnott
                                   Title: V.P. and CFO

WITNESS OR ATTEST:             GEOMET TECHNOLOGIES, INC.


/s/ Lula Fasold                By: /s/ Lawrence W. Sinnott            (SEAL)
--------------------------         --------------------------
                                   Name:  Lawrence W. Sinnott
                                   Title: Treasurer


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