PROJECT 3 FINAL REPORT

Brian KimballJames ColettaChad Higgins

Toyosi Bamidele

28 April, 2010

Team 4

Abstract

Innovation will be the driving force behind future market impact products. Our goal is to create a new and innovative design for sale in the private sector. We have identified a problem which we could address in the healthcare industry and created our own solution. Our final design is a ceiling fixture which uses UV light to kill harmful bacteria and viruses. We analyzed customer needs, and have done a great deal of research on our topic. We generated many of design ideas and then picked through them to find the most ideal final design. Techniques such as triz and other concept generating methods help us with this process. The UV sanitizer turned out to be a successful project which could be used to address our problem statement. The design successfully completes the goal of the project by fully sanitizing hospital rooms. Also after calculating the energy and material cost the project seems even more viable because it would be cheap to use. We originally had some concerns with the safety aspect of our design. However we have included certain safety measures which would insure no harm to any individual. The UV sanitizer meets the objectives of the project, solves an important problem, and satisfies all the customer needs we have identified. Because sanitation is a huge problem in hospitals we think that our design would be in great demand in such a market.

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1.0 Introduction

In modern hospitals, sanitation is a serious concern. The risk of infection is much higher for those whose immune systems are already weakened, so a significant amount of care must be taken to protect patients from pathogens in the hospital environment. In the past basic procedures have been taken to kill germs in health care environments, including hand washing and the use of latex gloves. Additionally, innovations such as antimicrobial surfaces have made sanitation much more effective (“Sanitation”). However, with the advent of new bacteria strains such as MRSA and other resistant pathogens, new sanitation measures are necessary.

In the last 20 years, new bacteria strains have cropped up which are significantly more resistant to drugs and sanitation measures than strains of the past. However, experiments have shown that ultraviolet light is capable of destroying up to 95% of a bacteria population when it is exposed to the UV light for one minute (Beck, pg. 1). Taking all of this into consideration, we have attempted to create a device which uses UV light to destroy bacteria in a hospital environment.

1.1 Initial Problem Statement

To combat hospital sanitation problems, we will design a device which utilizes UV light to kill pathogens in the environment. Additionally, this device will use no more than 100 Watts of DC power, where the power source comes from the ceiling.

2.0 Customer Needs Assessment

To gain a better sense of what our customers value in a sanitation product, we performed a customer needs assessment with an AHP pairwise comparison.

Table 1. Initial Customer Needs List Obtained from Focus Group and Individual Interviews

SafeDurableLow NoiseReasonable Retail PriceEasy to operateEasy maintenanceUser friendly EfficientSmall SizePower requirement under 100 WattsDoesn’t harm other materialsGood coverage

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Table 2. Hierarchal Customer Needs List Obtained from Focus Group and Individual Interviews

1. Safety 1.1 Doesn’t harm other materials2. Efficiency 2.1 Small Size 2.2 Durable 2.3 Good coverage 2.C Power requirement under 100 Watts3. User friendly 3.1 Low Noise 3.2 Easy to operate 3.3 Easy maintenanceC.1 Reasonable Retail Price

2.1 Weighting of Customer Needs

Safety Efficiency User Friendly Total Weighting

Safety 1 7 9 17 0.70

Efficiency 0.14 1 5 6.14 0.25

User Friendly 0.11 .2 1 1.31 0.05

Figure 1. AHP Pairwise Comparison Chart to Determine Weighting for Main Objectives

Size Durability Coverage Total Weighting

Size 1 0.25 .11 1.36 0.06

Durability 4 1 .13 5.13 0.12

Coverage 9 8 1 20 0.82

Low Noise Ease to Operate Maintenance Total Weighting

Low Noise 1 .5 .25 1.75 0.14

Ease to Operate 2 1 .33 3.33 0.25

Maintenance 4 3 1 8 0.61

Figure 2. AHP Pairwise Comparision Chart to Determine Weighting of Sub-Objectives

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Table 3. Weighted Hierarchal Customer Needs List Obtained from Focus Group and Individual Interviews

1. Safety (0.70, 0.70) 1.1 Doesn’t harm other materials (1, 0.70)2. Efficiency (0.25, 0.25) 2.1 Small Size (0.06, 0.015) 2.2 Durable (0.12, 0.03) 2.3 Good coverage (0.82, 0.205) 2.C Power requirement under 100 Watts3. User friendly (0.05, 0.05) 3.1 Low Noise (0.14, 0.007) 3.2 Easy to operate (0.25, 0.0125) 3.3 Easy maintenance (0.61, 0.1525)C.1 Reasonable Retail Price

We have identified safety as our number one customer needs concern. If our product isn’t safe then it will never be approved for use in a hospital. Efficiency is also important, because the system must be effective at killing bacteria and viruses across the entire room or else it is useless. Finally the third most important need is user friendliness. This means the product should be easy to install and not have much maintenance. This is important although safety and effectiveness will take the priority. We can use the results from our customer needs preparation for future project design and concept selections.

3.0 Revised Problem Statement

To combat hospital sanitation problems, we will design a safe, efficient, user friendly device which utilizes UV light to kill pathogens. Ideally, the device won’t harm other materials, have good coverage, and be easy to maintain. The device will use no more than 100 Watts of DC power, and the power source will come from the ceiling.

4.0 External Search

To gain a better understanding the design needs for our product, we conducted an external search to gather more information.

4.1 Literature Review

Sanitation in hospitals has become an ongoing problem dating back to the early 20th century. Several sources and ways of bacteria getting into the air and onto doctors tools have contributed to this. A study in 1970 was done by several people who indicated that wet mops used by hospital janitors helped to spread bacteria throughout hospitals. Mops that were stored wet

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supported bacteria growth; these bacteria could not be eliminated through chemical disinfection. There have also been other problems in hospital sanitation, including rusty water that contaminates the water stream. From these problems, we have conducted research to design a tool which will constantly decontaminate a hospital room by ultraviolet light.

Ultraviolet light has been used to disinfect water since 1916. Since then, research for this light has declined and new ways to disinfect water have been improved. Several states are making laws and regulations that allow water systems to be disinfected by these ultraviolet lights. Although our device is not specifically designed for water, ultraviolet light, in general, has the same effect. Specifically, for water, the ultraviolet light is held up to it and the radiation is exposed, decontaminating it. The ultraviolet light works to penetrate a bacterium’s cell walls, making the reproduction impossible. Overall, this device, if placed in a patient’s room, will kill bacteria and prevent it from coming back.

4.2 Experimentation

Electricity can flow in two different ways: in an alternating current or a direct current. The word electricity comes from the fact that current is nothing more than electrons moving along a conductor, like a wire, that have been harnessed for energy. The difference between AC and DC has to do with the direction in which the electrons flow.

In an AC Current the electron current keeps switching directions. Sometimes it will go forward and other times will go in the reverse direction. The electricity that comes out of a power socket in the wall is AC. AC is superior to DC in that it can travel further without losing energy and can deliver different amounts of energy. It is also safer and can deliver more energy than DC. A transformer can be used to alter the amount of power delivered by an AC current.

DC current is an older form of electricity power. The electrons can only flow in one direction. If a small appliance were to use a DC current for its power it could save electricity. This occurs because outlet power is DC current transformed into AC current. Some energy is lost in the transformation. This means that by eliminating this transformation we could save energy.

This loss of power during transformation is a testable occurrence. Our team decided to test this effect by using an actual appliance, a coffee maker. The coffee maker runs on a known wattage. If we can determine the difference between the power input and the wattage used by the coffee maker we can find the loss of energy between DC and AC transformation.

Table 4: Coffee Maker Power RequirementBox List Power (Watts) Actual Power (Watts) Difference

1025 950 75

In the experiment, we measured 75 watt difference between the power requirement listed on the box and the actual requirement from the Wattmeter. Unexpectedly, the actual power requirement was less than what was described by the company. We theorized that the actual resistance in the coffee maker’s circuit could have been different than resistance required for 1025 watts.

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Table 5: Theoretical Coffee Maker ResistanceBox List Power (Watts) Current (Amps) Resistance (Ohms)

1025 8.3 14.9

Table 6: Actual Coffee Maker ResistanceActual Power (Watts) Current (Amps) Resistance (Ohms)

950 8.3 13.8

To find the resistance generated by the coffee maker, we derived an equation relating wattage and current from two equations describing electrical current:

W =VIV=IR

W =I2 RWhere W is wattage, V voltage, R resistance, and I is current. Through the third equation and the wattage/current measurements from the Wattmeter, we were able to derive the values for resistance found in Tables 2 and 3. The value actual value for resistance is 1.1 ohms lower than the theoretical one. It is likely that the company overestimated the power requirement to make sure that the appliance would run. Given that power is lost in the transition from AC current to DC current, it is also likely that they overstated the power requirement by even more than 75 watts.

In our project we are required to design an appliance which would fit to the ceiling and could run off of 100 Watts of DC current. Using the DC current will save energy, but it is clear from our test results that we should still overestimate the power requirement for our appliance. If this is not done, it is possible that our appliance will not be able to run on only 100 watts of DC current.

4.3 Patent Search

A patent search was also performed to determine which existing technologies should be incorporated in the new product’s design. Table 7 summarizes the results, establishing which patents meet the function and art requirements of our project.

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Table 7. Art-Function Matrix for UV Sanitizer

FUNCTION ARTBattery charger Ultraviolet bulb The body of the

devicePlug Engine

Charges the device US 2354877Provide light required to kill bacteria

US D313606

To encompass the other parts of the device

US 5301398

To provide current flow in order for the device to work.

US 377184

To provide energy. US Des. 294832

US 3935525: This patent provided us with ideal type of battery charger needed to power up our ultraviolet bulb. It provides improvements in battery chargers as well as information on batteries with high and low charging rates.

US D313606: This patent provided us a description of the type of bulb needed to provide sanitation. It shows the perspective view of an ultraviolet bulb as well as its design.

US 5301398: This patent provides us with a description of a plastic bodied object. It provides the design concept that will match the body of the ultraviolet sanitizer that we are trying to make.

US 377184: This patent provides us with a typical plug that will be useful to the creation of our device .In order for current to flow so that power can be produced.

US Des.294832:This patent provides a detailed description of the engine and how it can be incorporated in our product.

4.4 Benchmarking

To gain a better sense of how an ultraviolet sanitizer would compare to existing products on the market, benchmarking was used to compare existing UV germicidal lamps to standard cleaning products such as Dettol, Purell, and Lysol. Table 8 exhibits the results.

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Table 8. BenchmarkingFeature Dettol Purell Lysol Germicidal Lamp

Safe 4 4 4 2

Durable 1 1 1 5

Low Noise 5 5 5 2

Reasonable Retail price

4 4 4 2

Easy to operate 4 4 4 3

Easy to maintenance

4 4 4 2

Efficient 3 3 3 5

Small size 3 3 3 2

Power requirement under 100 watts

5 5 5 5

No harm on other materials

3 3 3 2

Good coverage 2 2 2 5

While benchmarking, we determined that although the germicidal lamp was somewhat less safe and cost more, it was much more efficient than the other products on the market. Unlike Purell, Lysol, and Dettol, the germicidal lamp could be reused indefinitely. Also, it provided much better coverage than the other products.

Figure 3. Germicidal Lamp vs. Purell

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4.5 Design Target

Through the external search, we found that ultraviolet light could be used as an effective germicide because it destroys a bacterium’s ability to reproduce, thus causing the entire colony to die off. In benchmarking, we were able to establish that our product should be safe, but still be efficient and have good coverage. Experimentation with DC power showed that it would be more efficient to create a device that runs directly off of DC power, rather than one that converts from AC to DC in the device.

5.0 Concept Generation

5.1 Problem Clarification

Figure 4. EMS Model

To clarify exactly what our problems our product should address, we used the EMS model. As can be seen in Figure 4, how we needed to figure out how to utilize a power source to kill dangerous bacteria. The energy from the power source would used to power the ultraviolet light, which would in turn be rotated across the room to destroy pathogens.

5.2 Concept Generation

Our first concept design is the shape of the system. We could keep it simple by making it into a rectangular box shape. If we use a triangle shape for our system then we could have a greater range of movement for the Infrared light. Finally we could place the system in dome, such as one placed around some ceiling security cameras. If we needed to this dome could also be designed to filter the light in some fashion.

Our second concept to consider is where the system will fit on the ceiling electrical grid. We could place it in the center of the room and run a wire to it, or have it directly under a grid line in the power system.

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The method of delivery is also important. A simple concept would be to have a single light source without direction projecting at 360 degrees. However; if we can concentrate the light it would be more effective at killing pathogens. Another method would concentrate the light through a relatively small rectangular gap, and the beam would be rotated across 180 degrees of motion. Still, we could have the light sources rotate on a ball joint to swivel in a free 360 fashion.

A charger is important to our design because the needed light intensity would probably be greater than the 100 wattage allowance. While the machine is not turned on and in hibernation the charger could slowly collect energy for use when needed.

The most important part of our design aspect is to keep the machine from being a safety hazard. To ensure that the infrared light sweep isn’t activated accidentally we will need some sort of lock. One idea is to have a single key and a flip switch to activate the sweep. Alternatively, a security code system could be installed.

A warming system should be included in the design to make sure no one is in the area to be cleansed. A recorded verbal warning could be used. Or a flashing red light and beeping sound to warn those nearby of the activation is also acceptable.

The interior light design must produce a strong source of infrared light, while still being relatively low energy and as maintenance free as possible.

6.0 Preliminary Concept Selection

To decide which design aspects met our customer needs, we utilized Pugh charts to draw a comparison:

1. Location

Safet

yEffiecienc

y User-FriendlyTota

lRan

kWeighting 0.7 0.25 0.05 Iteration 1 A 0 1 0 0.25 1B 0 2Iteration 2 A 0 1

B 0 -1 0-

0.25 2 A-Center B-Off-Center

Figure 5: Pugh Chart for Location

For location, we observed its safety and user-friendliness did not matter. However, we felt that for efficiency, the center location was better than the off-center position.

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2. Shape

SafetyEfficienc

y User FriendlyTota

lRan

kWeighting 0.7 0.25 0.05 Iteration 1 A 0 0 1 0.05 1B 0 0 0 0 2C 0 2Iteration 2 A 0 0 1 0.05 1B 0 2C 0 0 0 0 2Iteration 3 A 0 1

B 0 0 -1-

0.05 2

C 0 0 -1-

0.05 2A-Dome B-Square C-Triangle

Figure 6: Pugh Chart for Shape

In terms of shape, the only component that mattered was user-friendliness. Its shape did not affect safety or efficiency. We concluded that the dome shape was the most user-friendly.

3. Method of Delivery

Safety EfficiencyUser

Friendly TotalRan

kWeighting 0.7 0.25 0.05 Iteration 1 A 0 1 0 0.25 1B 0 -1 0 -0.25 3C 0 2Iteration 2 A 0 1 0 0.25 1B 0 2C 0 1 0 0.25 1Iteration 3 A 0 1B 0 -1 0 -0.25 2C 0 -1 0 -0.25 2

A-180 Degrees B-BulbC-360 Degrees

Figure 7: Pugh Chart for Method of Delivery

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For delivery, we concluded that efficiency was the only relevant component. For this, 180 degrees was the best fit.

4. Safety System

Safet

yEffiecienc

yUser-

FriendlyTota

lRan

kWeighting 0.7 0.25 0.05 Iteration 1 A -1 0 0 -0.7 2B 0 1Iteration 2 A 0 2B 1 0 0 0.7 1 A-Key and Switch B-Security Code

Figure 8: Pugh Chart for Safety System

Regarding safety, a security code was better. It provides a system that gives less of a chance for someone who is unauthorized to use.

5. Warning System

Safet

yEffiecienc

yUser-

FriendlyTota

lRan

kWeighting 0.7 0.25 0.05 Iteration 1

A -1 -1 0-

0.95 2B 0 1Iteration 2 A 0 2B 1 1 0 0.95 1

A-Voice WarningB-Beeping Alarm/Light

Figure 9: Pugh Chart for Warning System

The warning system had two relevant components: safety and efficiency. For these, the beeping alarm system provided a safer experience for the user as well as a more efficient system.

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6. Interior Light Design

Safet

yEffiecienc

yUser-

FriendlyTota

lRan

kWeighting 0.7 0.25 0.05 Iteration 1 A -1 -1 -1 -1 2B 0 1Iteration 2 A 0 2B 1 1 1 1 1 A-Multiple Bulbs B-One Bulb

Figure 10: Pugh Chart for Light Design

For light design, we were deciding between one bulb and multiple bulbs. However, we concluded that one bulb was clearly more efficient, safer, and more user-friendly.

7.0 Concept Refinement with TRIZ

Through the use of TRIZ, we were able to refine our approach to the problem at hand:

Journalistic Approach of Problem AnalysisWho has the problem?

-Hospitals all over the world.What is the problem?

-There is a problem with sanitation in hospitals which results in many patients becoming re-infected. I new method of sanitation is required to make hospitals safe for the patients.When does the problem occur?

-While sick patients are recovering in their hospital bed.Why does the problem occur?

-Modern sanitation techniques are not strong enough to protect people from rapidly evolving bacteria and viruses.

Harmful effects/Inefficiencies :The UV light must be strong enough to kill the bacteria and viruses without harming the

physical environment. There are also safety concerns which must be addressing to make sure no one is in the room during activation.

Design problems: Brightness Vs Waste of energy: 13, 16, 1, 6Power Vs Harmful side effects: 2, 35, 18Shape Vs Energy Spent by moving object: 2, 6, 34, 14Strength Vs Energy spent by stationary object: 35

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Design Principles:Physical or chemical properties, Other way around, partial or excessive action, Segmentation, Universality, separation or extraction, mechanical vibration, recycling, spherical shapes.

Design ideas generated through TRIZ:- Possible Dome shape- Material used to create product/ properties of chosen plastic- Limit space in object to prevent movement of pieces and extend life of product.

8.0Final Design

The final design features a germicidal ultraviolet lamp mounted inside a plastic casing. The plastic casing is adhered to the ceiling through use of multiple screws to hold it in place. The chamber for the lamp is rotated by a small motor, and the chamber is also coated with mirroring substance to reflect all of the UV rays onto one location outside the device.

8.1 Materials and material selection

Over the course of the design process, it was decided that the casing should be made from plastic. This casing would receive no ill-effects from the ultraviolet light. All other parts of the product are made from existing items such as the motor and germicidal lamp.

8.2 List of Materials

Table 9 provides a list of materials for the product. The plastic casing would need to be custom made, but all other parts could be purchased from a light bulb production company or Home Depot.

Table 9. List of required materials and components

Qty Description Catalog Number Vendor Total Cost1 Germicidal UV Bulb G25T8 Top Bulb 13.794 Wall screws, diam=1/4" Home Depot 2.381 Plastic casing (custom made)1 Motor (custom made)

Total Cost 16.17

8.3 Assembly instructions

Assembly is actually very simple. The UV light should fit securely in the space provided. The battery and motor also have a designated location which should snap into the plastic molding. Finally the entire system should be screwed into the ceiling in the desired location.

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9. Design Calculations

A 20W Ultraviolet bulb that is used for 3 minutes would effectively kill the bacteria in the given area. This would not affect the price of an electric bill at once (one-time use is negligible). The amount of use is up to the discretion of the customer. We estimate that a typical hospital would use this device approximately two to three times per day. Therefore, a monthly electric bill would charge the use of this device about $0.01. Overall, we feel that this product can become very successful in its use with the low cost of power it consumes and its effectiveness to sanitize.

10.0 Conclusions

The UV sanitizer turned out to be a successful project which could be used to address our problem statement. The design successfully completes the goal of the project by fully sanitizing hospital rooms. Also after calculating the energy and material cost the project seems even more viable because it would be cheap to use. We originally had some concerns with the safety aspect of our design. However we have included certain safety measures which would insure no harm to any individual. Also after an extensive literature search we have discovered that the light would not be dangerous to plastics, clothes or metals in a hospital room. Our research on UV light shows its effectiveness on killing bacteria and viruses, so the machine would be effective. Its inexpensive design would allow hospitals to have several machines in each room if they so choose. The UV sanitizer meets the objectives of the project, solves an important problem, and satisfies all the customer needs we have identified. Because sanitation is a huge problem in hospitals we think that our design would be in great demand in such a market.

References

Beck, Alyssa. "What Are the Effects of Ultraviolet Light on Bacteria Mortality?." CALIFORNIA STATE SCIENCE FAIR (2004): 1. Web. 21 Apr 2010. <http://www.usc.edu/ CSSF/History/2004/Projects/J1303.pdf>.

"Hospital Sanitation: Wire Baskets for Protecting Life." Marketinia (2008): n. pag. Web. 21 Apr 2010. <http://www.marketinia.com/hospital-sanitation-wire-baskets-protecting-life/>.

"Hospital Sanitation: the Massive Bacterial Contamination of the Wet Mop." (1971): n. pag. Web. 21 Apr 2010. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC377258/>.

Turney, W.G. Hospital Sanitation - Where Are We Now? (1965): n. pag. Web. 21 Apr 2010. <http://www.cccminc.com/hospital_sanitation.htm>.

"Ultraviolet Disinfection." Tech Brief (2000): n. pag. Web. 21 Apr 2010. <http:// www.nesc.wvu.edu/pdf/dw/publications/ontap/2009_tb/ultraviolet_dwfsom53.pdf>.

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"What is alternating current (AC)?." All About Circuits n. pag. Web. 7 Apr 2010. <http://www.allaboutcircuits.com/vol_2/chpt_1/1.html>.

"What is the difference between AC and DC current?." WiseGeek n. pag. Web. 7 Apr 2010. <http://www.wisegeek.com/what-is-the-difference-between-ac-and-dc.htm>.

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