STEMM Report

STEMM Report

(Figure 1. Juvenile Horseshoe crab)

Introduction:

The Horseshoe crab is a marine organism that dates back to prehistoric times with very little change its physical appearance or eating habits. However, despite the fact that these animals have existed for many years, they are currently facing a serious threat. The Horseshoe crab population has been steadily declining for the past few decades due to a number of different reasons, which include over-fishing, harvesting for the medical properties of their copper-infused blood, and from natural predation by the Red Knots during their migration season. Regardless of the reason, measures must be taken to increase the survivability percentage of Horseshoe crabs. This is a problem that scientists and engineers are attempting to remedy, with little to no success as of late.

The method that my partner and I have chosen to attempt to increase survivability is a rearing habitat that will house Horseshoe crabs from 6 months to 1 year old, before releasing them into the wild. This project has been split up in to two separate portions. Ms. Synek will be in charge of designing and constructing the physical structure of the tank, while taking in to consideration that amount of water needed for the Horseshoe crabs as well as how to promote easy access to the Horseshoe crabs. My portion of the project is to design and construct a fully functional water flow system, which will deliver water to each compartment of the tank, mimic the natural conditions that Horseshoe crabs experience in their habitat, and provide the proper nutrients that are needed for growth and development in Horseshoe crabs.

How this project relates to Systems Engineering:

The water flow system for the tank that I am designing counts as an innovation, as the technology and ideas of pipes that transport water and regulate conditions have been around for many years. The type of engineering that is involved in such a project includes both biological and hydrodynamic engineering. Biological engineering is the use of scientific concepts, such as the environmental conditions and nutritional intake that the Horseshoe crabs require, and applying them to solve problems in the real world. My project also has its ties in hydrodynamic engineering, as I must design the system to move the water through the pipes at a constant speed capable of creating aeration in the water upon contact.

In this project, the water flow system will be manufactured by myself, having researched methods on how to properly cut and fit PVC pipes, after bringing the materials to the construction site, which in this case is the Systems Engineering shop. This method of manufacturing most closely relates to the method of prefabrication. Many of the parts that will be assembled during this process will remain in their original form, with only small adjustments or cuts having to be made by myself, and will reach the final level of construction upon being fitted or glued together. This method of manufacturing is simple and best fits my project, as all that is required of me is to bring the materials that are needed (See Plan of Procedures for more details) to the Systems Engineering shop, and assemble them into the final product.

                               (Figure 2. Model of water delivery pipe)

As my project is to create a water flow system that will be made primarily of PVC pipes to transport water and provide nutrients, the system falls under the manufacturing categories of engineering and plastics. Engineering was a crucial part of the development of the water flow system as the size, shape, and placement of each PVC pipe (Figure 2) would have critical effects on Ms. Synek’s tank, and vice versa. Should the weight of my pipes be too great for the tanks to hold steady, the whole structure could collapse on top of the reservoir tank. I also had to take the needs of Ms. Synek’s tank into consideration so that our designs could be properly integrated. If the reservoir tank that I chose was not structurally sound, the tank resting about it could not possibly be held steady, thus risking the lives of our Horseshoe crabs and the success of this project. The water flow system also falls under the plastic manufacturing category, as almost all of the materials that will be used in the construction of this system will be made of plastic PVC piping. This means that during the design phase of this project, I had to take the thickness of the PVC pipe walls into consideration, as that would determine the amount of water going through the system at any given moment, as well as the structural integrity of the piping.

Scientific concepts:

There were many different scientific concepts that I had to take into consideration while designing my solution for this project. These concepts had to do with the designs that I focussed on during the planning stages of this project, and shaped my final solution so as to fit to the concepts. One of the first concepts that I explored was the salinity of the water that I will be using in the water flow systems. Horseshoe crabs live in saltwater environments, meaning that in order for them to thrive, the water must be of similar salinity. To accomplish this task, water will be taken directly from the New York Bay to be transferred into the tank at the NOAA lab, where it will be run through a closed system. The concept of the salinity of the water also introduced the scientific concept of acidification in to my water flow system. Due to the corrosive effect of the saltwater on most metals, I had to design the system so that it would be fully functional despite being submerged in saltwater for large amounts of time. With this challenge in mind, I eliminated most metal components of the system in the early designing stages of the project, and replaced them with PVC piping, which would not be susceptible to the acidification presented by the constant saltwater.

Some other scientific concepts that I had to incorporate into the design for my water flow system had to do with the well-being of the Horseshoe crabs. Dissolved oxygen and temperature are two of these concepts that play a large role in the growth and development of our Horseshoe crabs. As with most other marine organisms, Horseshoe crabs can not survive unless oxygen is present in the water, so my design had to have a way for the water to be aerated. I came up with a two part solution in order to solve this problem. As the water flows down through the main water delivery tube (Shown in Figure 2), the water is naturally aerated from being churned up as the water surface is disturbed from the falling water. The next step in this solution simply relies on air stones, which will be placed in each compartment of the tank in order to provide even more dissolved oxygen to the Horseshoe crabs.

Another scientific concept that I have had to use in the design for my water flow system is the idea of fluid dynamics. My designs rely heavily on the water being able to move smoothly throughout each compartment of the tank, so in the design stage, take the flow of the water into consideration was extremely important. Each pipe in the system has to equally distribute the water into the different compartments so that each group of Horseshoe crabs experiences the same conditions. The concept that water follows the path of least resistance has been a constant worry in the water flow system, as I must ensure that the water follows the path that the system requires.

(Figure 3. Representation of submersible pump)

Technology concepts:

In this project, technology has aided me in performing homeostasis on the tank environment so that the Horseshoe crabs can survive and thrive in this makeshift habitat. The first piece of technology that I am using to regulate the tank environment is a water chiller. This water chiller allows me to control the temperature of the water so that the temperature remains at a level that supports Horseshoe crab development, which is approximately 25-40 degrees celsius. The second piece of technology that is being used in the water flow system allows every other aspect of this project to happen. The pump (Figure 3) is what will force the water up through each side of the tank into the separate pipes so that the water will flow into each compartment of the tank. The output of the pump must be measured exactly so that the amount that is being pumped into the tank corresponds with the rate that water is being flushed out through the drainage pipe. If the pump output is stronger than the rate at which the water is being drained, than the tank will overflow. This is also a problem vice-versa, as the water will drain out faster than the pump can fill the tank, leading to a lack of water that will eventually kill the Horseshoe crabs.

(Figure 4. AutoCAD model of tank.)

Mathematical computations:

In the Simulated Horseshoe Crab Habitat project, the main mathematical computation that I had to focus on during the designing stages of this project was the equation for the fluid flow rate. As stated in previous paragraphs, the output from the pump can not exceed the rate at which the water is flowing through the drainage pipe, nor should the number fall under that rate. Therefore, in order to calculate the fluid flow rate, I used the equation pgzSurface + Patm = ½ pV jet ^2 + pgzSpout + Patm. In this equation, the rate at which water will flow through a small opening, such as the three vertical openings on the side of the drainage pipe (Figure 3), is determined by taking the pressure of the water at the depth of the spout and adding to the pressure at the surface. This equation can equal ½ of the pressure of the “jet” that comes from the spout, plus the same pressure as the free surface. A model of this equation can be seen in Figure 5. The variables that are needed for this equation are the difference of the depth of the spout and the water depth, the fluid density, the exit diameter of the spout, and the discharge coefficient. By using this equation, I can find the fluid flow rate in terms of gallons per hour, which I can then match up to my pump output so that the two are equal.

(Figure 5. Model of Fluid flow equation)

Conclusion:

The Simulated Horseshoe Crab Habitat is a design that will incorporate a physical tank and a water flow system, The water flow system, which will be of my own design, will be an innovation of an already existing idea. This water flow system will be categorized as both an example of biological and hydrodynamic engineering, as the environmental conditions that must be recreated are examined as scientific theories applied to this problem, and the movement of water throughout the pipe system allows for this project to have ties in hydrodynamic engineering as well. All materials on the Plan of Procedures will be gather by myself and brought to the Systems Engineering shop for manufacturing. The method of construction best resembles the prefabrication manufacturing style. Once all parts have been assembled, the Simulated Horseshoe Crab Habitat will contain one large tank, where the Horseshoe crabs are kept, a smaller reservoir tank for the water, a pipe system for transporting water throughout the system, and environmental controlling devices so as to keep the habitat close to the environment the Horseshoe crabs are naturally raised in. The concept of fluid dynamics is essential for the success of this project, as the water must flow to each compartment in the tank in equal amounts and at equal velocity, so as to keep conditions the same throughout the tank. The pump is the piece of technology that makes allows for the water flow system to succeed, as without a pump to move the water through the PVC piping, the conditions in each part of the tank would be different, which could be detrimental to the health of the Horseshoe crabs. The mathematical computation that I have relied on for this project is the equation for determining the rate at which fluids flow through an opening. This equation allows me to find exactly how fast water will be draining out of the tank, and therefore how strong the output on the pump must be in order to balance that drain. After all construction has been completed, the Simulated Horseshoe Crab Habitat will be able to house approximately 50 juvenile Horseshoe crabs for a period of 6 months, and will be used by future Oceanography students to conduct further studies on the species.

Works Cited

"Aquarium Submersible Pump NP-80." Www.truaqua.com. N.p., n.d. Web. 28 Jan. 2014.

Ehlinger, Gretchen. "Result Filters." National Center for Biotechnology Information. U.S. National Library of Medicine, Apr. 2004. Web. 28 Jan. 2014.

"Flowrate Calculation for a Draining Tank." Flowrate Calculation for a Draining Tank. N.p., n.d. Web. 28 Jan. 2014.

"Fluid Flow from a Vessel." Fluid Flow from a Vessel. N.p., n.d. Web. 28 Jan. 2014.