1 PDS v 3 0 Date May 4 2004 Title Hypoxia Group Members Aaron Huser Cole Kreofsky Dana Nadler Joe Poblocki Problem Statement The purpose of this project is to design a system that can create a reproducible and accurate hypoxic hyperoxic environment with the capability of oscillating between various concentrations of oxygen and nitrogen Client Requirements Variable gas concentrations and flow rates through a rat holding chamber Software with an easy to use interface and customizable features that controls the mass flow controllers Accurate mass flow controllers digital or analog Uniform hose Low sound level Design Requirements 1 Physical and Operational Characteristics a Performance requirements This system needs to accurately control the flow so that the concentration of gas moving through the rat holding chambers is precise The system must be quiet and fit its surroundings so that it does not upset the rats The software controlling the system must consist of a graphical user interface that is easy to use and efficient 2 b Safety The system should be neat and orderly so that the technicians do not trip over any hoses or cables c Accuracy and Reliability The accuracy must be no greater then 1 of the set point flow and the mass flow controllers must operate around 50 100 of their maximum flow for optimal accuracy The reproducibility of the flow must be no greater then 0 2 of the maximum flow d Life in Service The system must be able to endure eight hours of testing a day for at least ten years with periodic recalibration e Shelf Life If the system is not in use it should last indefinitely in a laboratory atmosphere f Operating Environment The environment will be a research room on the 2nd floor of Veterinary Science building in Madison WI which is part of the University of Wisconsin The temperature pressure range humidity and noise levels will be that of a typical lab environment and should not constrain the design in any way The system will be handled by experienced researchers and lab technicians who have a background in gas flow systems and limited software knowledge g Ergonomics The system must be neatly organized with the many wires and hoses neatly arranged Any display especially computer software should have a user friendly interface that can be customized and understood easily No component of the system should be difficult to unhook or reattach in the case of a repair or an accident All equipment must be clearly labeled and connected to its proper component The rat chambers must be lightweight and identifiable The size of the chambers must afford comfort for the rat and efficiency for the gas use concentration Gas must flow into the chamber must be even and constant as to not upset the rat h Size The system must all fit on an average size desk with a small table at the end approximately 3 feet by 7 feet All components should be able to be moved by any 3 individual and have clear access for maintenance Rat chambers should follow the criteria found in Ergonomics i Weight The mass flow controllers will weigh between 300 400 grams a piece and each sits independently allowing for the system to be moved about readily j Materials A translucent polymer should be used on the rat chamber in order to observe the behavior for anything abnormal during actual testing The mass flow controllers will be purchased from a manufacturer and therefore will contain various non hazardous materials Cabling and components will also be purchased from a manufacturer and will be safe to use k Aesthetics Appearance and Finish All the mass flow controllers will be from the same manufacturer and all the rat chambers will be made of the same translucent material The final system should be neat and orderly 2 Production Characteristics a Quantity The client will need two mass flow controllers per rat holding chamber for the client s current projection there will be eight chambers and thus sixteen mass flow controllers A communication cable is needed for each mass flow controller in order to receive instructions from the computer The client will also need software to operate the mass flow controllers and the client will need uniformly manufactured rubber hose b Target Product Cost The cost of each mass flow controller will range from 1100 to 1700 These will be purchased from manufacture of the client s choice The software will be written and made into an executable file using LabVIEW at no cost through the College of Engineering However the client can still opt to purchase a copy of LabVIEW for further programming and editing 3 Miscellaneous a Standards and Specifications Since the mass flow controllers and hose will be purchased from a current manufacturer which meets International Organization for Standardization 4 ISO gas flow standards The software needs to include a graphical interface and should automate as much of the experiment as possible b Customer The main users of this system will be graduate students and lab technicians in the veterinary school who will use it for research purposes These customers are most concerned with functionality accuracy and repeatability not so much with aesthetics or size c Patient related concerns The patients for this design are rats The client wants to minimize any environmental changes so that the rat s seratonin levels remain normal This includes but is not limited to noise color etc Competition There are several mass flow controller manufacturing companies Mass flow controllers have a few different ways of determining gas flow but the accuracy is the most important factor Most mass flow controllers have 1 2 accuracy but a few have 1 The fall back for the greater accuracy is an increase in price HyperTerminal is the only software competition aside from personally developed software
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