EXHIBIT 10-d

Wells Fargo Equipment Finance, Inc.                              Promissory Note
733 Marquette Avenue, Suite 700
MAC N9306-070
Minneapolis, MN  55402
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                                                       Dated as of July 25, 2003

For value received, the undersigned, hereby promises to pay to the order of
Wells Fargo Equipment, Inc. (the "Lender") at its office in Minneapolis,
Minnesota, or at such other place as may be designated from time to time by the
holder hereof, the sum of $2,065,776.60 in installments according to the
schedule set forth below; provided, however, that the undersigned and the Lender
may agree to any other payment schedule, in which case any variations shall be
set forth in the space provided for additional provisions. The first payment
period shall begin on the 15th day of the month in which Lender disburses the
loan proceeds if disbursement is made on or before the 15th day of such month,
and the first payment period shall begin on the last day of such month if
disbursement is made during the balance of such month. The first installment
shall be payable on the first payment due date set forth below (which may be the
same as the date the first payment period begins). Subsequent installments shall
be payable on the first day of each payment period beginning after the first
payment period. The undersigned agrees that the date the first payment period
begins may be left blank when this Note is executed and hereby authorized Lender
to insert such date based upon the date the loan proceeds are disbursed.



                                                            
PAYMENT SCHEDULE:
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Date first payment period begins:                              First payment due:
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Number of Installments: 60                                     Amount of each installment: $34,429.61
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Payment period: Monthly                                        Annual Interest rate used in computing payment schedule: 6.73%
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Principal amount of loan proceeds disbursed: $1,750,000.00
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In addition to installment payments as set forth above, the undersigned agrees
to pay Lender interim interest on the loan proceeds disbursed hereunder from the
date of disbursement to the date the first payment period begins at the annual
interest rate set forth above used in computing the payment schedule. Interim
interest shall be due and payable on the date the first payment period begins.

If any installment is not paid when due, then in addition to any other remedy
Lender may have hereunder, Lender may impose and, if imposed, the undersigned
shall pay a late charge of 5% of the amount of the delinquent installment but in
any event not more than permitted by applicable law. Payments thereafter
received shall be applied first to delinquent installments and then to current
installments.

This note may not be prepaid in whole or in part at any time.

The following shall constitute an Event of Default hereunder: (a) failure to pay
any installment hereunder when due; (b) the occurrence of an event of default as
defined in any security agreement or mortgage securing this Note; (c) the
commencement of any bankruptcy or insolvency proceedings by or against the
undersigned or any guarantor of this Note; and (d) any indebtedness the
undersigned may now or hereafter owe to Lender or any affiliate thereof shall be
accelerated following a default thereunder or, if any such indebtedness is
payable on demand, payment thereof shall be demanded. Upon the occurrence of an
Event of Default, Lender may do any one or more of the following as it may
elect: (i) upon written notice to the undersigned, declare the entire unpaid
balance of the Note to be immediately due and payable, and the same (less
unearned interest computed using the simple interest method as if this Note had
been paid in full on the date it became due and payable) shall thereupon be and
become immediately due and payable: (ii) exercise any one or more of the rights
and remedies available to it under any security agreement or mortgage securing
this Note or under any other agreement or by law.

The undersigned hereby waives presentment, notice of dishonor, and protest. The
undersigned agrees to pay all costs of collection of this Note, including
reasonable attorneys' fees. The holder hereof may change the terms of payment of
the Note by extension, renewal or otherwise, and release any security for, or
party to, this Note and such action shall not release any accommodation maker,
endorser, or guarantor from liability on this Note.

Notwithstanding anything to the contrary contained herein, if the rate of
interest, late payment fee, prepayment premium or any other charges or fees due
hereunder are determined by a court of competent jurisdiction to be usurious,
then said interest rate, fees and/or charges shall be reduced to the maximum
amount permissible under applicable law and any such excess amounts shall be
applied towards the reduction of the principal balance of this Note.

This Note shall be construed and enforced in accordance with, and the rights of
the parties shall be governed by, the laws of the State of Minnesota with regard
to conflicts of law rules.

If this Note is signed by more than one person as Debtor, then the term "Debtor"
shall refer to each of them separately and to all of them jointly, and each such
person shall be liable hereunder individually in full and jointly with the
others.

IN WITNESS WHEREOF the debtor has signed the Agreement as of the date first
above written.


Thermodynetics, Inc.                       Vulcan Industries, Inc., Debtor
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Debtor                                     Debtor

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By                                         By

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Title                                      Title