I. OVERVIEW

Baylor University Largeman Labs (BULL), hereafter referred to as the client, has obtained an exclusive contract to supply DNA analyzers for the Federal Bureau of Investigation (FBI). The client wishes to focus its own engineering talent on the mass spectrometry aspects of the analyzer design, and outsource other functions to qualified subcontractors.

As part of Project Double Helix Unraveled, this Request for Proposal (RFP) seeks to invite qualified engineering firms to design and document a prototype Aqueous Solution Device (ASD). An ASD is an integral part of a DNA analyzer in that the speed of analysis is greatly enhanced by partially dissolving the test subject in water, alcohol, or other liquids.

II. BACKGROUND

Any type of organism can be identified by examination of DNA sequences unique to that species. Identifying individuals within a species is less precise at this time, although when DNA sequencing technologies progress farther, direct comparison of very large DNA segments, and possibly even whole genomes, will become feasible and practical and will allow precise individual identification.

To identify individuals, forensic scientists scan 13 DNA regions that vary from person to person and use the data to create a DNA profile of that individual (sometimes called a DNA fingerprint). There is an extremely small chance that another person has the same DNA profile for a particular set of regions.

Some Examples of DNA Uses for Forensic Identification

Identify potential suspects whose DNA may match evidence left at crime scenes
Exonerate persons wrongly accused of crimes
Identify crime and catastrophe victims
Establish paternity and other family relationships
Identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers)
Detect bacteria and other organisms that may pollute air, water, soil, and food
Match organ donors with recipients in transplant programs
Determine pedigree for seed or livestock breeds
Authenticate consumables such as caviar and wine

Source: Human Genome Project,
http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml
III. DESIGN SPECIFICATION

1. User Need Statement:

The liquid dispenser system should:

1.1 Function: The device must dispense 20 ± 1-ml of water into plastic sample containers for subsequent DNA processing. There may be, at one time, up to seven (7) plastic sample containers for processing. Any spillage outside the sample containers will result in contamination.

1.1.1 Sample container check: The device should be capable of accepting up to seven plastic sample containers. However, the device must also allow for the use of fewer than seven, including zero. The device must be able to determine when a sample container is present and dispense water only under that condition.

1.2.1 Over fillage: The possibility exists to process the same container repeatedly. This would eventually result in water spillage. Such spillage is considered user error. The device is not required to sense partially filled containers.

1.2 Water Level: The water is to be drawn from a reservoir, the initial level of which must be below the bottom surface of the containers to be filled. (See illustration.)

1.3 Sequence: Containers are to be filled sequentially from the same dispensing spout/nozzle (i.e., water cannot be dispensed through multiple nozzles, either simultaneously or sequentially.) At the completion of one container, the next empty container shall be moved into place and filled. Although the device is only required to hold a minimum of seven containers, it must be able to continually process containers if the user replaces filled containers by empty ones during the process (see 1.4).

1.4 Interrupt and Resume: The device shall have a user control capable of interrupting the progression of sample containers. The purpose of this control is to allow the user to add or remove containers as required. Two operational modes will therefore be required. The “Pause” mode will cease container movement and water filling so that containers may be added or removed. The “Process” mode will process containers for filling, dispense the water, and repeat. The device should stay in either the “Pause” or “Process” mode indefinitely until changed by the user.

1.4.1 Partial filling avoidance: In the event that the Interrupt control is engaged during the filling of a sample container, the device will complete that filling and then enter “Pause” mode. This last sample container shall also be accessible for removal after such event. Container movement to allow this condition is acceptable.

1.5 Operation: The system operation shall require one electrical switching action for initiation and one electrical switching action for termination. This may or may not be identical to the Interrupt and Resume control.

1.5.1 Setup: The system shall be capable of being setup/assembled and readied for operation within five minutes of the beginning of a testing trial.

1.5.2 Operation Time: Upon initiation, and in the absence of interrupts, the device shall be able to process containers at a rate of approximately 8.5 seconds per container, which results in seven containers processed per minute.

1.5.3 Size: The system, during operation, shall fit within a cubic space 24 inches on a side. Exception: Power cords and/or other wiring may extend outside the cube as negotiated with the client.

3. Design Documentation

The design team shall document the project by use of manuscripts, calculations, and computer models/drawings. Specifications for required documentation and due dates are contained in the course calendar and/or will be distributed at appropriate points during the project.

4. Safety Requirements

All parts of the system holding or transporting water must operate over or within a plastic pan or tray capable of containing the total volume of water in the system in the event of a spill. This requirement applies to all stages in the design, development, testing, and demonstration of the system in order to prevent spillage from damaging tabletops and flooring, or from creating dangerous footing conditions in the laboratories, workshops, and classrooms.

All electrical power – particularly if 120 VAC is used – must be properly grounded, properly insulated from water, and otherwise adhere to applicable electrical codes. Negligence and/or indifference in meeting these requirements, or in reporting violations thereof, are grounds for failure of this course.

The system in operation shall not present an undue hazard to persons or property. Appropriate safeguards and/or labeling should be in place (for example, for electrical components, pinch points, rotating parts, etc.).

All fabrication required for the development of the system will be conducted with proper adherence to the general safety guidelines in place for the Engineering Department laboratories and workshops. In addition, specific safety measures will be followed for each tool used in the fabrication process. Negligence and/or indifference in meeting these requirements, or in reporting violations thereof, are grounds for failure of this course.

Cleanliness in the workplace is expected at all times and in all work areas. Failure to observe departmental workplace rules will lead to penalties in performance evaluation. The design team shall clean all work areas with each use.