Creative Design Strategies
Designing an artificial heart by utilizing a creative process is intended to create an educational and physical environment that will put the students in the zone of proximal learning. This concept in conjunction with constructivist learning will engage students in an extremely challenging and difficult task. The intention is to captivate the students' interest enough to overcome their initial incredulity that the task is attainable. The students' discomfort at the momentous task is intentional and is a highly unusual experience for students. Typically tasks and problem solving is limited to manageable and comfortable steps that lead to a predetermined or predictable outcome. This is a different approach! In fact, the intention is to create a context in which the students are pushed beyond what they believe they can achieve. The problem posed is meant to be beyond their immediate grasp and experiential knowledge. This state of temporary discomfort is known as the zone of proximal learning and I believe creates the real life environment and skills to pursue truly authentic problem solving in which the solutions are neither obvious, proscribed nor guaranteed. However, the intention is to captivate the students' imagination and creativity.
In addition, the process provides some engineering strategies to approach the problem. In particular, the students are placed in a cooperative team setting that makes team work crucial both for the purpose of collaboration and drawing on the each team members' individual strengths as well as to maintain the enthusiasm of the group. The team members must trust the process in order to begin to pursue the task and to move toward the possibility of a successful outcome and the production of a prototype!
Few of my students will have embarked on a task with a group that is self-defined and largely self-motivated. It is intentional to envision and construct a task that is a bit overwhelming at first, because it is my belief, informed by having participated in the process of creative design as a stone fabricator, a sculptor, a physicist and as a teacher, that the greater the challenge the greater the sense of accomplishment. So the goal with this task of designing an artificial heart is to put the students in a zone that will stretch them, engage their confidence in themselves and their peers on their team, and provide them with a rich experience that will transform their sense of what is attainable. I believe that this is true education and learning.
Most of my students do not have a sense of working with materials in a process of physical and mental problem solving, so they must be provided with some practical skills of construction. It is also essential to provide them with a wealth of materials that will stimulate their creativity. The students' must also be provided with a method to approach the task. The task may be daunting but the teacher of creative design provides practical guidelines and an approach to problem solving based on defining the problem, establishing the required parameters, breaking the problem down into manageable parts or systems, brainstorming creative solutions, evaluating possible alternative solutions or approaches using concrete methods, productive teamwork that helps determine optimum participation from each team member, provides continual encouragement, values the process as much as the outcome, and encourages iterations that allow for the continual refinement and reevaluation of ideas and approaches. This process is meant to engage and empower the individual learner and the group. The student's engagement with meaningful problem solving is enhanced, their capacity for confronting and overcoming challenge and frustration is greatly increased and the difficulty of the problem is re-envisioned as an invitation to explore the creative process of generating possibility.
As an educator, it is my conviction that the process of creation is a profound experience. Coupled with the experience of substantive problem solving I believe this makes creative design a profound, memorable and potentially formative learning experience for students that is well worth the extended time and effort required. If this is accomplished, the rewards for all who participate are great.
The Process of Developing A Creative Design Project
In order for this process to be successful, the first step is that the proposed problem must be well conceived and compelling. I believe that designing and creating an artificial heart is captivating because we all take our beating heart for granted, but upon reflection, it is truly an awesome organ and my second year physics students can grasp the problem and apply a wealth of knowledge about mechanics to problems about fluid dynamics with which they are much more unfamiliar. I am confident, however, that my students have enough conceptual knowledge of physical systems to make the task of building a prototype of their own design extremely challenging but discernable. The background information that I provide will enable my students to define the problem and apply their conceptual and mathematical knowledge of Newtonian Mechanics to create exciting mechanical solutions. I am confident that creating a tangible prototype will be tremendously rewarding.
The second step for me, as the teacher, after having envisioned the problem, is to investigate a multiplicity of possible solutions to the problem! I have achieved an initial prototype of a simulated beating heart with the help of Stephen Griffith, who co-invented the first prototype, Rajendra Jaini (the co-creator of the idea of "Sexy Science") and constant enthusiast and technical supporter, Tom Barkus, who was invaluable in formulating the original conceptions of an artificial heart as a hydraulic press, Wolfgang and Gertrud Mergner, whose medical expertise of the heart was both an inspiration and an invaluable resource, and Mark Saltzman whose tutelage has instilled in me a passion for and knowledge of biochemical processes and physiology. We have collectively succeeded in creating the prototype which is pictured below.
Diagram 2
The third step towards realizing the building of an artificial heart as a successful curriculum unit is to find and accumulate materials that will allow the students to find creative and innovative solutions to the problem. I continue to explore materials that will stimulate the students' imaginations and activate their comprehension of mechanics and simple machines. Within my ability I will allow the students the opportunity to seek out materials and request the fabrication of manageable parts based on their design parameters and technical drawings. The goal is to enable the students to envision solutions and interact with mechanical parts in a physical way to seek out solutions both conceptually and physically. In the meeting of these two separate processes, I believe the deepest learning and success will occur. I will do my best to facilitate the fluidity of design and construction.
The next step is to create the scaffolding that will enable the students to define the problem, break the problem into sub-systems, explore the materials for potential and optimal solutions to the subsets and support the students in successfully looping back on these steps while encouraging them to remain engaged and enthusiastic.
In order to begin building the artificial heart, the students most likely will need to see potential places to start. This is a delicate balancing act as a teacher of creative design. A balance must be struck between engaging the students' creativity and providing too much information or examples that will steer the students in a particular direction.
The last step is to continue to create a satisfying, stimulating and supportive classroom laboratory environment that will allow for controlled risk-taking and experimentation. The students must remain invested, curious, motivated and content with their progress toward the goal of creating a prototype. All groups must be supported at whatever stage they are at and all students must be encouraged to engage in the process and to realize that effort is its own reward and a successful design can only be achieved by trial and error and failures are an essential part of the road to success. I am confident that the students will embrace the project and inevitably will surprise me with their own innovations!
Promising Prototype Designs
I have developed promising ideas for prototypes. The first, and simplest, is to place a pump (already built) in-line with a "heart" or bladder. This is the most prevalent design currently for artificial hearts but it is not simplified enough. The students and myself are not able to build a functional pump from scratch, so it is my inclination that this option is not direct enough and does not draw on my students' mechanical knowledge, although there are plenty of auxiliary issues to get this design to work and to optimize it. It is my hope that my students can conceive of their design based on simple machines and Newtonian physics. The second design requires a motor and a cam. The cam, as in the diagram of the first prototype (Diagram 2), operates much like a heart that is contracting and relaxing. The cam is attached to a motor and provides two "beats" per cycle. Two hinged boards are compressed by springs onto a cam shaft and a bladder representing the heart sits closest to the hinge. The cam is oval and when it is in its vertical position the heart is most full. As the cam rotates the heart quickly "contracts" or beats causing an ejection of fluid from the heart (which is attached to a "capillary bed" as indicated in the diagram. As the cam rotates another 90° the cam is again vertical and the heart is "relaxed". Check valves are attached that only allow the fluid to flow in one direction, as indicated by the purple arrows on the diagram of the prototype. The third prototype involves the cam directly compressing the bladder. Although this provides a compressing force that provides a flow, it is much more gradual, involving the majority of the stroke of the cam, and consequently does not as closely simulate the heart beat as the diagrammed prototype, unless a pressure valve were designed to open only when the pressure reached a certain point. This would in effect provide a beat like an actual heart. The last design for a prototype involved a cam mounted on top of the hinged-levered boards. The cam and motor would have to be mounted to the bottom board, while in contact with the top board. However, this design has the same problem as the third design, in that the long stroke of the cam is the contraction and the short stroke is the relaxation, which is the reverse of the heart.
Although we did not produce a prototype for piston-activated contraction, we did spend a considerable time thinking about how they might be utilized. In our brain storming designs we imagined, like a two cylinder engine, that one piston could force downward while the second "linked" piston would travel upward. We tried to envision how this could act like the heart but were unable to effectively solve the problem. However, it seems worth exploring the possibility that at least to some extent, the double piston could potentially act as two separate pumps that in some ways could simulate the two sides of the heart.
So far we have only developed a prototype with one chamber. It is yet to be determined if there are ways to design a heart that might simulate the action of the atrium as well. By producing so many promising ideas and a functioning prototype that requires only a motor, (currently a geared down electrical motor, which certainly could be optimized to be battery powered and much smaller, maybe even allowing for the motor to be turned around and interior to the hinge allowing for a much smaller "heart") I am confident that my students can produce their own designs and prototype that only require simple machines and a motor!
History of Artificial Heart Design and Development
The remarkable effort to produce a fully functioning artificial heart entirely contained within the body has only achieved limited success. There are such devices that exist but they are not permanent and are utilized as a means to prolong patients' lives, hopefully, until they can get a human heart transplant. Most of the problems with the artificial heart are related to the issues that we discussed regarding biocompatibility, but there are other issues. One unsolved problem is the source of power, which results in cumbersome rechargeable batteries. Although a promising option exists, (provided by RF (radio frequency) power sources, like the battery source that powered our Vagus Nerve Stimulation Apparatus and Associated Methods invention), which are external to the device and the body and therefore, easily replaceable. Another issue is the difficulty of making the artificial heart entirely contained within the body, and complications involving infection inevitably arise from long term breaches in the skin. There are still many issues to be resolved for the artificial heart to be able to satisfy the tremendous need that exists. This is an additional reason for my students to get exposure to the problem and the process of biomedical engineering design.
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