Exhibit 3.1
                                                                     -----------

                          AMENDED AND RESTATED BY-LAWS
                                       OF
                                 TVI CORPORATION

                               ARTICLE I - OFFICES
                               -------------------

     The principal  office of the  Corporation in the State of Maryland shall be
located  at such  place  as the  Board  of  Directors  may,  from  time to time,
determine. The Corporation may also maintain offices at such other places within
or without the United  States as the Board of Directors  may, from time to time,
determine.

                      ARTICLE II - MEETING OF SHAREHOLDERS
                      ------------------------------------

Section 1 - Annual Meetings:
----------------------------

     The annual meeting of the  shareholders  of the  Corporation  shall be held
within five months  after the close of the fiscal year of the  Corporation,  for
the purpose of electing  directors,  and transacting  such other business as may
properly come before the meeting.

Section 2 - Special Meetings:
-----------------------------

     Special meetings of the shareholders may be called at any time by the Board
of Directors or by the  President,  and shall be called by the  President or the
Secretary  at the written  request of the holders of not less than a majority of
all shares then  outstanding  and  entitled  to vote  thereat,  or as  otherwise
required under the provisions of the Maryland General Corporation Law.

Section 3 - Place of Meetings:
------------------------------

     All meetings of shareholders  shall be held at the principal  office of the
Corporation,  or at such other places as shall be  designated  in the notices or
waivers of notice of such meetings.

Section 4 - Notice of Meetings:
-------------------------------

     (a)  Written  notice of each  meeting of  shareholders,  whether  annual or
special, stating the time when and place where it is to be held, shall be served
either  personally  or by mail,  not less than ten (10) or more than ninety (90)
days before the meeting,  upon each  shareholder  of record  entitled to vote at
such meeting,  and to any other  shareholder to whom the giving of notice may be
required  by law.  Notice of a special  meeting  shall also state the purpose or
purposes for which the meeting is being  called,  and shall  indicate that it is
being  issued by, or at the  direction  of, the  person or persons  calling  the
meeting.  If, at any  meeting,  action is proposed  to be taken that  would,  if
taken,  entitle shareholders to receive payment for their shares pursuant to the
Maryland  General  Corporation  Law, the notice of such meeting  shall include a
statement of that purpose and to that  effect.  If mailed,  such notice shall be
directed to each such  shareholder at his address,  as it appears on the records
of the  shareholders of the  Corporation,  unless he shall have previously filed
with the Secretary of the  Corporation a written  request that notices  intended
for him be mailed to some other  address,  in which case,  it shall be mailed to
the address designated in such request.

<PAGE>

     (b) Notice of any meeting  need not be given to any person who may become a
shareholder of record after the mailing of such notice and prior to the meeting,
or to any shareholder who attends such meeting, in person or by proxy, or to any
shareholder who, in person or by proxy, submits a signed waiver of notice either
before or after such meeting.  Notice of any adjourned  meeting of  shareholders
need not be given, unless otherwise required by statute.

Section 5 - Quorum:
-------------------

     (a) Except as otherwise provided herein, or by statute,  or in the Articles
of  Incorporation  (such Articles and any amendments  thereto being  hereinafter
collectively referred to as the "Articles of Incorporation"), at all meetings of
shareholders  of the  Corporation,  the  presence  at the  commencement  of such
meetings in person or by proxy of  shareholders  holding of record a majority of
the total number of shares of the  Corporation  then issued and  outstanding and
entitled to vote,  shall be necessary and  sufficient to constitute a quorum for
the  transaction of any business.  The withdrawal of any  shareholder  after the
commencement  of a meeting  shall have no effect on the  existence  of a quorum,
after a quorum has been established at such meeting.

     (b)  Despite  the  absence of a quorum at any annual or special  meeting of
shareholders,  the shareholders,  by a majority of the votes cast by the holders
of shares  entitled  to vote  thereon,  may  adjourn  the  meeting.  At any such
adjourned  meeting at which a quorum is present,  any business may be transacted
which might have been transacted at the meeting as originally called if a quorum
had been present.

Section 6 - Voting:
-------------------

     (a)  Except  as  otherwise  provided  by  statue  or  by  the  Articles  of
Incorporation,  any corporate action, other than the election of directors to be
taken by vote of the  shareholders,  shall by  authorized by a majority of votes
cast at a meeting of  shareholders  by the  holders of shares  entitled  to vote
thereon.

     (b)  Except  as  otherwise  provided  by  statute  or by  the  Articles  of
Incorporation,  at each meeting of shareholders, each holder of record of shares
of the Corporation  entitled to vote thereat,  shall be entitled to one vote for
each share registered in his name on the books of the Corporation.

     (c) Each  shareholder  entitled  to vote or to  express  consent or dissent
without a meeting, may do so by proxy;  provided,  however,  that the instrument
authorizing  such  proxy to act  shall  have been  executed  in  writing  by the
shareholder  himself,  or by his  attorney-in-fact  thereunto duly authorized in
writing.  No proxy shall be valid after the expiration of eleven months from the
date of its  execution,  unless the persons  executing  it shall have  specified
therein the length of time it is to continue in force.  Such instrument shall be
exhibited to the Secretary at the meeting and shall be filed with the records of
the Corporation.

     (d) Any resolution in writing,  signed by all of the shareholders  entitled
to vote thereon,  shall be and  constitute  action by such  shareholders  to the
effect therein expressed, with the same force and effect as if the same had been
duly passed by unanimous vote at a duly called meeting of shareholders  and such
resolution  so signed  shall be inserted  in the Minute Book of the  Corporation
under its proper date.

<PAGE>

                        Article III - Board of Directors
                        --------------------------------

Section 1 - Number, Election and Term of Office:
------------------------------------------------

     (a) The  number  of the  directors  of the  Corporation  shall be ten (10),
unless and until otherwise  determined by vote of a majority of the entire Board
of Directors.

     (b) The members of the Board of Directors of the Corporation,  who need not
be  shareholders,  shall be elected by a majority of the votes cast at a meeting
of shareholders, by the holders of shares entitled to vote in the election.

     (c) Each  director  shall  hold  office  until the  annual  meeting  of the
shareholders  next  succeeding his election,  and until his successor is elected
and qualified, or until his prior death, resignation or removal.

Section 2 - Duties and Powers:
------------------------------

     The Board of Directors  shall be responsible for the control and management
of the affairs, property and interests of the Corporation,  and may exercise all
powers of the Corporation  except as are in the Articles of  Incorporation or by
statute expressly conferred upon or reserved to the shareholders.

Section 3 - Annual and Regular Meeting; Notice:
-----------------------------------------------

     (a) A  regular  annual  meeting  of the  Board of  Directors  shall be held
immediately  following the annual meeting of the  shareholders,  at the place of
such annual meeting of shareholders.

     (b) The Board of  Directors,  from time to time,  may provide by resolution
for the holding of other regular meetings of the Board of Directors, and may fix
the time and place thereof.

     (c) Notice of any regular  meeting of the Board of  Directors  shall not be
required to be given and, if given, need not specify the purpose of the meeting;
provided,  however,  that in case the Board of Directors shall fix or change the
time or place of any regular  meeting,  notice of such action  shall be given to
each  director  who shall not have been  present  at the  meeting  at which such
action  was  taken  within  the time  limited,  and in the  manner  set forth in
paragraph  (b) of  Section  4 of this  Article  III,  with  respect  to  special
meetings,  unless  such  notice  shall be  waived  in the  manner  set  forth in
paragraph (c) of such Section 4.

<PAGE>

Section 4 - Special Meetings; Notice:
-------------------------------------

     (a)  Special  Meetings  of the Board of  Directors  shall be held  whenever
called by the  President or by one of the  directors,  at such time and place as
may be specified in the respective notices or waivers of notice thereof.

     (b) Notice of special  meetings shall be mailed  directly to each director,
addressed to him at his  residence or usual place of business,  at least two (2)
days before the day on which the meeting is to be held,  or shall be sent to him
at such place by  telegram,  electronic  mail (to any  electronic  mail  address
provided by the  director  to the  Company)  radio or cable or other  electronic
means, or shall be delivered to him personally or given to him orally, not later
than the day before the day on which the  meeting  is to be held.  A notice,  or
waiver of notice,  except as required by Section 8 of this Article III, need not
specify the purpose of the meeting.

     (c) Notice of any special  meeting shall not be required to be given to any
director who shall attend such meeting  without  protesting  prior thereto or at
its  commencement,  the lack of notice to him, or who submits a signed waiver of
notice,  whether  before or after the meeting.  Notice of any adjourned  meeting
shall not be required to be given.

Section 5 -  Chairman:
----------------------

     At all meetings of the Board of  Directors,  the Chairman of the Board,  if
any and if present, shall preside. If there shall be no Chairman, or he shall be
absent, then the President shall preside,  and in his absence, a Chairman chosen
by the Directors shall preside.

Section 6 - Quorum and Adjournments:
------------------------------------

     (a) At all meetings of the Board of  Directors,  the presence of a majority
of the entire Board shall be necessary and sufficient to constitute a quorum for
the  transaction  of  business,  except as  otherwise  provided  by law,  by the
Articles of Incorporation, or by these By-Laws.

     (b) A  majority  of the  directors  present  at the time  and  place of any
regular or special  meeting,  although less than a quorum,  may adjourn the same
from time to time without notice, until a quorum shall be present.

Section 7 - Manner of Acting:
-----------------------------

     (a) At all meetings of the Board of Directors,  each director present shall
have one vote,  irrespective  of the number of shares of stock, if any, which he
may hold.

     (b)  Except  as  otherwise   provided  by  statute,   by  the  Articles  of
Incorporation,  or by these  By-Laws,  the action of a majority of the directors
present  at any  meeting  at which a quorum is  present  shall be the act of the
Board of Directors.  Any action authorize,  in writing,  by all of the directors
entitled to vote thereon and filed with the minutes of the corporation  shall be
the act of the Board of Directors  with the same force and effect as if the same
had been passed by unanimous vote at a duly called meeting of the Board.

<PAGE>

Section 8 - Vacancies:
----------------------

     Any vacancy in the Board of Directors occurring by reason of an increase in
the   number  of   directors,   or  by  reason   of  the   death,   resignation,
disqualification, removal (unless a vacancy created by the removal of a director
by the shareholders  shall be filled by the shareholders at the meeting at which
the removal was  effected) or inability to act of any  director,  or  otherwise,
shall be filled for the unexpired  portion of the term by a majority vote of the
remaining  directors,  though  less than a quorum,  at any  regular  meeting  or
special meeting of the Board of Directors called for that purpose.

Section 9 - Resignation:
------------------------

     Any director may resign at any time by giving  written  notice to the Board
of  Directors,  the  President  or  the  Secretary  of the  Corporation.  Unless
otherwise  specified in such written notice,  such resignation shall take effect
upon  receipt  thereof  by the  Board  of  Directors  or such  officer,  and the
acceptance of such resignation shall not be necessary to make it effective.

Section 10 - Removal:
---------------------

     Any  director  may be  removed  with or  without  cause  at any time by the
shareholders,  at a special meeting of the shareholders called for that purpose,
and may be removed for cause by action of the Board.

Section 11 - Salary:
--------------------

     No stated salary shall be paid to directors,  as such, for their  services,
but by  resolution  of the  Board  of  Directors  a fixed  sum and  expenses  of
attendance,  if any,  may be allowed for  attendance  at each regular or special
meeting of the Board; provided,  however, that nothing herein contained shall be
construed  to preclude any director  from serving the  Corporation  in any other
capacity and receiving compensation therefor.

Section 12 - Contracts:
-----------------------

     (a) No contract or other transaction between this Corporation and any other
Corporation shall be impaired,  affected or invalidated,  nor shall any director
be liable in any way by reason of the fact that any one or more of the directors
of this Corporation is or are interested in, or is a director or officer, or are
directors or officers of such other  Corporation,  provided  that such facts are
disclosed or made known to the Board of Directors.

     (b) Any director, personally and individually,  may be a party to or may be
interested in any contract or transaction of this  Corporation,  and no director
shall be liable in any way by reason of such interest, provided that the fact of
such interest be disclosed or made known to the Board of Directors, and provided
that the Board of Directors shall authorize,  approve or ratify such contract or
transaction  by the vote  (not  counting  the vote of any  such  director)  of a
majority of a quorum,  notwithstanding  the presence of any such director at the
meeting at which such action is taken. Such director or directors may be counted
in determining the presence of a quorum at such meeting.  This Section shall not
be construed to impair or  invalidate or in any way affect any contract or other
transaction,  which would otherwise be valid under the law (common, statutory or
otherwise) applicable thereto.

<PAGE>

Section 13 - Committees:
------------------------

     The Board of Directors,  by resolution  adopted by a majority of the entire
Board,  may from time to time  designate  from among its  members  an  executive
committee and such other committees, and alternate members thereof, as they deem
desirable,  each  consisting  of three or more  members,  with such  powers  and
authority  (to  the  extent  permitted  by  law)  as may  be  provided  in  such
resolution. Each such committee shall serve at the pleasure of the Board.

                              Article IV - Officers
                              ---------------------

Section 1 - Number, Qualifications, Election and Term of Office:
----------------------------------------------------------------

     (a) The  officers  of the  Corporation  shall  consist  of a  President,  a
Secretary,  a Treasurer,  and such other  officers,  including a Chairman of the
Board of Directors,  and one or more Vice Presidents,  as the Board of Directors
may from time to time deem advisable. Any officer other than the Chairman of the
Board  of  Directors  may be,  but is not  required  to be,  a  director  of the
Corporation.  Any two or more offices may be held by the same person, except the
offices of President and Secretary.

     (b) The  officers  of the  Corporation  shall be  elected  by the  Board of
Directors  at the  regular  annual  meeting  of the Board  following  the annual
meeting of shareholders.

     (c) Each officer shall hold office until the annual meeting of the Board of
Directors next succeeding his election,  and until his successor shall have been
elected and qualified, or until his death, resignation or removal.

Section 2 - Resignation:
------------------------

     Any  officer  may  resign  at any time by  giving  written  notice  of such
resignation  to the Board of Directors,  or to the President or the Secretary of
the  Corporation.  Unless  otherwise  specified  in such  written  notice,  such
resignation  shall take effect upon receipt thereof by the Board of Directors or
by such officers,  and the acceptance of such resignation shall not be necessary
to make it effective.

Section 3 - Removal:
--------------------

     Any officer may be removed,  either with or without cause,  and a successor
elected by the Board at any time.

Section 4 - Vacancies:
----------------------

     In the absence or incapacity  of any officer,  or in the event of a vacancy
in any office,  the Board of Directors may designate any person to fill any such
office pro tempore or for any particular purpose.

<PAGE>

Section 5 - Duties of Officers:
-------------------------------

     Officers of the Corporation  shall,  unless otherwise provided by the Board
of  Directors,  each have such powers and duties as  generally  pertain to their
respective  offices  as well as such  powers  and  duties as may be set forth in
these By-Laws, or may from time to time be specifically  conferred or imposed by
the Board of Directors.  The President shall be the chief  executive  officer of
the Corporation.

                           Section 6 - Other Officers
                           --------------------------

     The Board of  Directors  may, in the exercise of its  discretion,  elect or
appoint  such other  officers who shall have such powers and perform such duties
as the  Board of  Directors,  the  Chairman  of the  Board of  Directors  or the
President may from time to time prescribe.

Section 7 - Sureties and Bonds:
-------------------------------

     In case the Board of Directors shall so require,  any officer,  employee or
agent of the  Corporation  shall execute to the  Corporation a bond in such sum,
and with  such  surety  or  sureties  as the  Board  of  Directors  may  direct,
conditioned  upon the  faithful  performance  of his duties to the  Corporation,
including responsibility for negligence and for the accounting for all property,
funds or securities of the Corporation which may come into his hands.

Section 8 - Shares of Other Corporations:
-----------------------------------------

     Whenever the Corporation is the holder of shares of any other  corporation,
any  right  or power  of the  Corporation  as such  shareholder  (including  the
attendance,  acting  and  voting at  shareholders'  meetings  and  execution  of
waivers,  consents,  proxies or other instruments) may be exercised on behalf of
the Corporation by the President,  any Vice  President,  or such other person as
the Board of Directors may authorize.


                           ARTICLE V- SHARES OF STOCK
                           --------------------------

Section 1 - Certificate of Stock:
---------------------------------

     (a) The  certificates  representing  shares of the Corporation  shall be in
such form as shall be adopted by the Board of  Directors,  and shall be numbered
and  registered in the order  issued.  They shall bear the holder's name and the
number of shares,  and shall be signed by (i) the  Chairman  of the Board or the
President  or a Vice  President,  and  (ii)  the  Secretary,  or  any  Assistant
Secretary, and may bear the corporate seal.

     (b) No  certificate  representing  shares  shall be  issued  until the full
amount of consideration therefor has been paid, except as otherwise permitted by
law.

     (c) The Board of Directors may authorize the issuance of  certificates  for
fractions of a share which shall entitle the holder to exercise  voting  rights,
receive dividends and participate in liquidating distributions, in proportion to
the  fractional  holdings;  or it may  authorize the payment in cash of the fair
value of fractions of a share as of the time when those entitled to receive such
fractions are  determined;  or it may  authorize  the issuance,  subject to such
conditions  as may be  permitted by law, of scrip in  registered  or bearer form
over the signature of an officer or agent of the  Corporation,  exchangeable  as

<PAGE>

therein provided for full shares, but such scrip shall not entitle the holder to
any rights of a shareholder, except as therein provided.

Section 2 - Lost or Destroyed Certificates:
-------------------------------------------

     The holder of any certificate  representing shares of the Corporation shall
immediately notify the Corporation of any loss or destruction of the certificate
representing  the same. The Corporation may issue a new certificate in the place
of any  certificate  theretofore  issued  by it,  alleged  to have  been lost of
destroyed. On production of such evidence of loss or destruction as the Board of
Directors  in its  discretion  may require,  the Board of Directors  may, in its
discretion, require the owner of the lost or destroyed certificate, or his legal
representatives,  to give the  Corporation  a bond in such sum as the  Board may
direct, and with such surety or sureties as may be satisfactory to the Board, to
indemnify the Corporation against any claims,  loss,  liability or damage it may
suffer on account of the issuance of the new certificate.  A new certificate may
be issued  without  requiring any such evidence or bond when, in the judgment of
the Board of Directors, it is proper so to do.

Section 3 - Transfers of Shares:
--------------------------------

     (a)  Transfers  of  shares  of the  Corporation  shall be made on the share
records of the Corporation only by the holder of record thereof, in person or by
his duly authorized attorney, upon surrender for cancellation of the certificate
or  certificates  representing  such  shares,  with an  assignment  or  power of
transfer endorsed thereon or delivered therewith duly executed,  with such proof
of the authenticity of the signature and of authority to transfer and of payment
of transfer taxes as the Corporation or its agents may require.

     (b) The Corporation  shall be entitled to treat the holder of record of any
share or shares as the absolute owner thereof for all purposes and, accordingly,
shall not be bound to  recognize  any  legal,  equitable  or other  claim to, or
interest  in, such share or shares on the part of any other  person,  whether or
not it shall have express or other notice thereof, except as otherwise expressly
provided by law.

Section 4 - Record Date:
------------------------

     In the event the share records of the Corporation are closed,  such records
may not be closed for a period  longer than twenty (20) days. In lieu of closing
the share  records  of the  Corporation,  the  Board of  Directors  may fix,  in
advance,  a date not exceeding ninety (90) days, nor less than ten (10) days, as
the record date for the determination of shareholders entitled to receive notice
of, or to vote at, any meeting of  shareholders,  or to consent to any  proposal
without a meeting,  or for the purpose of determining  shareholders  entitled to
receive payment of any dividends, or allotment of any rights, or for the purpose
of any  other  action.  If no  record  date is fixed,  the  record  date for the
determination  of shareholders  entitled to notice of or to vote at a meeting of
shareholders shall be at the close of business on the day next preceding the day
on which the  notice is given,  or, if no notice is given,  the day on which the
meeting is held;  the record  date for  determining  shareholders  for any other
purpose shall be at the close of business on the day on which the  resolution of
the directors relating thereto is adopted.  When a determination of shareholders
of record  entitled to notice of or to vote at any meeting of  shareholders  has
been  made as  provided  for  herein,  such  determination  shall  apply  to any
adjournment  thereof,  unless  the  directors  fix a new  record  date  for  the
adjourned meeting.

<PAGE>

                             ARTICLE VI - DIVIDENDS
                             ----------------------

     Subject to  applicable  law,  dividends may be declared and paid out of any
funds available therefor,  as often, in such amounts,  and at such time or times
as the Board of Directors may determine.

                            ARTICLE VII - FISCAL YEAR
                            -------------------------

     The fiscal year of the Corporation shall be fixed by the Board of
Directors from time to time, subject to applicable law.

                          ARTICLE VIII - CORPORATE SEAL
                          -----------------------------

     The corporate seal, if any, shall be in such form as shall be approved from
time to time but the Board of Directors.

                           ARTICLE IX-INDEMNIFICATION
                           --------------------------

Section 1 - Generally:
----------------------

     The  Corporation  shall  indemnify its directors to the fullest extent that
indemnification  of directors is permitted by the Maryland  General  Corporation
Law.  The  Corporation  shall  indemnify  its officers to the same extent as its
directors and to such further extent as is consistent  with law. The Corporation
shall  indemnify its  directors and officers who,  while serving as directors or
officers of the  Corporation,  also serve at the request of the Corporation as a
director,  officer,  partner,  trustee,  employee, agent or fiduciary of another
corporation,  partnership,  joint venture,  trust,  other enterprise or employee
benefit plan to the fullest extent consistent with law. The  indemnification and
other  rights  provided by this  Article  shall  continue as to a person who has
ceased to be a director  or officer and shall inure to the benefit of the heirs,
executors and administrators of such a person.

Section 2 - Advances of Expenses:
---------------------------------

     Any director or officer  seeking  indemnification  within the scope of this
Article  shall be entitled to advances from the  Corporation  for payment of the
reasonable expenses incurred by him in connection with the matter as to which he
is seeking  indemnification  in the manner and to the fullest extent permissible
under the  Maryland  General  Corporation  Law without  requiring a  preliminary
determination of ultimate entitlement of indemnification.

Section 3 - Other Arrangements Permitted:
-----------------------------------------

     The Board of Directors may make further  provision  consistent with law for
indemnification  and advance of expenses to directors,  officers,  employees and
agents by resolution,  agreement or otherwise.  The indemnification  provided by
this Article shall not be deemed  exclusive of any other right,  with respect to
indemnification  or  otherwise,  to which those seeking  indemnification  may be
entitled under any insurance or other agreement or resolution of stockholders or
disinterested directors or otherwise.

<PAGE>

Section 4 - Applicability of the Maryland General Corporation Law:
------------------------------------------------------------------

     References in this Article IX are to the Maryland General  Corporation Law,
as amended  from time to time.  No  amendment  of these  Bylaws shall affect any
right  of any  person  under  this  Article  based  on any  event,  omission  or
proceeding prior to such amendment.


                             ARTICLE X - AMENDMENTS
                             ----------------------

Section 1 - By Shareholders:
----------------------------

     All by-laws of the  Corporation  shall be subject to  alteration or repeal,
and new by-laws may be made, by a majority vote of the  shareholders at the time
entitled to vote in the election of directors.

Section 2 - By Directors:
-------------------------

     The Board of Directors shall have power to make, adopt,  alter,  amend, and
repeal, from time to time, by-laws of the Corporation:  provided,  however, that
the  shareholders  entitled to vote with  respect  thereto as in this  Article X
above-provided  may  alter,  amend  or  repeal  by-laws  made  by the  Board  of
Directors,  except that the Board of Directors shall have no power to change the
quorum for meetings of shareholders  or of the Board of Directors,  or to change
any  provisions  of the by-laws  with respect to the removal of directors or the
filling  of  vacancies  in  the  Board   resulting   from  the  removal  by  the
shareholders.  If any by-laws  regulating an impending  election of directors is
adopted, amended or repealed by the Board of Directors, there shall be set forth
in the notice of the next meeting of shareholders for the election of directors,
the by-law so adopted, amended or repealed, together with a concise statement of
the changes made.