From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-2.9 required=5.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,cc4f25d878383cc X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-12-27 09:21:04 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!canoe.uoregon.edu!arclight.uoregon.edu!fr.usenet-edu.net!usenet-edu.net!enst!enst.fr!not-for-mail From: "Steven Deller" Newsgroups: comp.lang.ada Subject: RE: Dimensionality Checking (Ada 20XX) Date: Thu, 27 Dec 2001 12:18:58 -0500 Organization: ENST, France Sender: comp.lang.ada-admin@ada.eu.org Message-ID: Reply-To: comp.lang.ada@ada.eu.org NNTP-Posting-Host: marvin.enst.fr Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Trace: avanie.enst.fr 1009473662 64795 137.194.161.2 (27 Dec 2001 17:21:02 GMT) X-Complaints-To: usenet@enst.fr NNTP-Posting-Date: Thu, 27 Dec 2001 17:21:02 +0000 (UTC) To: Return-Path: X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2627 In-Reply-To: <9vknmb$2vf$1@mvme66.ciw.uni-karlsruhe.de> X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Importance: Normal Errors-To: comp.lang.ada-admin@ada.eu.org X-BeenThere: comp.lang.ada@ada.eu.org X-Mailman-Version: 2.0.6 Precedence: bulk List-Help: List-Post: List-Subscribe: , List-Id: comp.lang.ada mail<->news gateway List-Unsubscribe: , Errors-To: comp.lang.ada-admin@ada.eu.org X-BeenThere: comp.lang.ada@ada.eu.org Xref: archiver1.google.com comp.lang.ada:18339 Date: 2001-12-27T12:18:58-05:00 Thomas, Actually, you are missing a divisor in your computation of vapor load. It actually is Vapor Load = V_l = V_cfs * sqrt( rho_v/(rho_l-rho_v)) and this results in length^3/time whole units: V_cfs = length^3/time rho_* = mass/length^3 so, length^3/time * sqrt( mass/length^3 / (mass/length^3 - mass/length^3)) = length^3/time The following site has a full chem eng distillation analysis: http://chemeng.uah.edu/courses/che446sp99/spray1.html Every computation I saw had full units (or unitless ratios). There did not seem to be a need for non-integral units. The line computing V_l states it is Vapor Load, ft/s but is is clearly cu ft/s (which makes more sense if one is computing a vapor load on a column). INMHO, fractional units simply make no sense for any stated value. They *might* occur in a partial computation, e.g. sqrt(length1) * sqrt(length2), though that would more properly be written as sqrt(length1*length2). I cannot think of any computation where fractional units *do* occur, even in partial results. It would be nice to have one clear example from the real world where fractional units occur before building a solution for something that will never be used. Regards, Steve > -----Original Message----- ... > > In order to be sufficiently general, dimensions would have to > be factional numbers for intermediate results, at least. > There are too many cases where square or cubed or other roots > turn up in normal calculations. > > For example, one important factor in distillation column > design, the vapor load, is defined as F = w * rho^(1/2), > where w is the speed in (Length/Time) and rho is the density > (Mass/Length^3), so its unit actually is kg^0.5/m^0.5/s in > SI units. And yes, people do publish values and correlations > for this factor. _______________________________________________ >