When working on the creation of a seven degree of freedom impedance controller for an iARM my project team encountered many delays due to a critical path. The controller was initially expected to be controlled using an RS232 shield with an Arduino Mega which would communicate between the iARM and the controller. This was not considered a critical path until we began to realize that the iARM was not receiving information from the RS232 shield but the shield was communicating with the Arduino Mega. Within the initial phase we planned to work on the RS232 shield within the month of October and move on to evaluating our design in November. However, by the end of October we were unable to create communication between the iARM and RS232 shield. My project team began to realize that we would not be able to meet our deadlines if we continued to try to figure out why the RS232 shield was not communicating with the iARM. So in the month of November instead of evaluating out prototype we switched our software and had to update all of our documents without utilizing the RS232 shield within our mechanical, electrical and software designs. A simple task of communicating between an RS232 shield and iARM which was supposed to take a month ended up setting us back for an entire month and caused us to redesign our entire project. We came to realize that if we spent more time researching the compatibility between an RS232 shield and iARM, we would have save so much time and money further on in the developing stages of the prototype.

A time when an extraneous task suddenly wound up on the critical path for the project is the discovery of Scotchgard stain repellent. Patsy Sherman, a researcher, who worked at 3M company as a chemist was assigned to work on fluorochemicals to develop a new kind of rubber for jet aircraft fuel lines. An assistant had accidently spilled a bottle of synthetic latex that Sherman had made on to his tennis shoes. It was discovered that the substance did not change the look of the shoes. Moreover, it could not be washed away by any solvent and repelled water, oil and other liquids. This accidently discovery lead 3M to investigate more money to further research this substance. Consequently, the 3M company decided to produced versatile fabric stain repellent and material protector, Scotchgard out of the substance Sherman made. Thus, Scotchgard is an example of a product that was meant for rubber of a jet but became got on a critical path of another project dealing with a fabric stain repellent.
Reference:
http://www.women-inventors.com/Patsy-Sherman.asp

Absolutely! One of the aspects of my thesis project was to develop an in vitro blood-brain barrier; primary cortical neuronal cells would be attached to the bottom of a well while endothelial cells and astrocytes would be suspended on either side of a transwell above the neurons. I thought the first task, culturing the neurons, would be very quick, simple, and, therefore, extraneous while executing the transwell would require time and development of skill. However, the neuronal culture was much more difficult than I anticipated and they became a critical path. It turned out that neurons are very fickle because they can get easily stressed by their surroundings and how they are handled and die. Cortical neuronal cells must be "wined and dined" needing proper time and handling skill for proper culture. From this development and under time constraint I turned my critical path into the focus of my project abandoning the transwell idea and instead studying concentrations of cytokines/HIV proteins on neuronal cell death, trying to pin-point a specific concentration to significant cell death. My seemingly insignificant cell culture turned into a critical path that made me reassess my project and, for time constraint reasons, made me change it.

Currently I'm working on my capstone project, and one of the tasks I thought to simple ended up becoming a part of the critical path. What I'm talking about is making components stay in place. For context, I'm designing a cast that will measure temperature and swelling in an affected area to help monitor how an individual is healing. One of the aspects of the design that is taking a significant portion of time is simply assembly and making everything as part one system and stay in place. For example, in order to make sure wires are secured, I sewed wires on a gauze under-layer. For other components, such as the arduino, we've designed a box to house it in our system. The devil's in the details, and figuring out something that seemed so trivial and component securement has ended up being a huge part of our critical path. We are constantly thinking of new ideas to optimize the design to secure all of our components in the best way possible.

Surprisingly, I actually ran into this last semester during my capstone project. I am trying to make a transparent skull to study the effects of traumatic brain injuries and in order to do that I have to get proper geometry of the skull. We used MRI files and converted that to a 3D model. One of things we have to look into are materials that are similar, mechanically, to skull but also transparent. After googling several we came up with a few ideas, seemingly easy. At the time we thought we could choose any material that met the requirements. However, we came to realize the feasibility of using such materials. To give you an example, one of the choices we came up with was PEEK (poly ether ether ketone). It is used in craniomaxillofacial implants and we thought it would be perfect to use this material. Feasibility wise, not so much. It is very very expensive and would require an industrial grade foundry to mold. Something so simple as choosing a material became one of our critical paths because we had to ensure we chose a material that met our requirements but was also feasible.

A critical path I identified occurred during the R&D phase of a project I was working on before it became a formal project. We were working on creating a surgical lavage and had found a substance that after multiple iterations and testing was optimized in performing it's intended function, or so we thought. It turns out that the physical form the substance was in allowed for greater optimization of the material. At first we were using it in it's standard form, but we discovered that using a sonicator allowed us to amplify the effects of the material in it's new form. At first we thought of the form the material was in as a nonfactor, however after various tests we were able to confirm and prove that changing the form of the material allowed for a more efficient product.

In designing a hip stem implant and running finite element analysis on it last semester. After creating the part file which took hours, and applying constraints and loads on the hip stem implant. After running 20 analysis to predict where our implant will fail, a very critical detail was left out. The threshold of a software and bugs in a software. The stem implant passed all of the analysis such as flexion, tension, axial loading test but it our results were never looked at from a real point of view. Yes the software and computational analysis turned out great. However, when the stem analysis were looked at by an expeirenced engineer he point out that there was a 20% chance that this stem design will fail and result in a fracture because the software is not able to predict real life scenarios. The stresses on the stem in real life can be very rare and the stresses and concentration the software predicts are limited. First off, the computer on which the software is installed does not have the capacity and speed to run fast and real life results. The software contains bugs and adds to limits to meshing tools. Giving inaccurate predictions. So the very small detail of environmental effects and comparative analysis which does not matter in the research phase, can be the most essential in the practical field. The stem was great but when compared to real life situations and materials added on the stem, our results had too much percent error to manufacture such a stem. The cost and time do not justify the computational results. So even though, these software are excellent, but the very small errors which we ignore and press ignore can lead to voiding a project or product.

I am also working on a capstone project where seemingly minor details have manifested into critical issues that impede the progress of the overall project. This is certainly something that has to be accounted for. One of these issues is contacting suppliers. We received the wrong part for one of our pinch valves and could not finish our preliminary model in time. We learned that procurement is a critical bottle neck that must be accounted for. This gave us a better understanding of these minor details and we adjusted our schedule accordingly to account for other details that may account for more delays.

When I was working with a 3D-printed foot orthosis project one of our side projects was testing out other possible materials to print it with. We had gotten all the way toward refining the final print design when we had learned that one of the materials we were researching was very much suitable for the requirements we had previously set. This however necessitated a redesign of the CAD model as some of the shapes had known difficulty printing with the new material. In the end, the new material didn't even end up working as expected so we had to revert everything back anyways.

One of the biggest events on campus is Reign or Shine, a dance competition hosted by FINEST club, Filipinos in Newark Engaging in Sociocultural Traditions. As part of e-board, I was in-charge of organizing the event including reserving the venue, inviting dance teams, the judges, the hosts, security, vendors, etc. Everything was planned properly except the contracts. At the day of the event, we needed consent and release forms which we did not foresee in advance. This caused the event to be delayed for a couple of hours due to legal reasons. It was important that the performers sign the release forms and assume responsibility for all damage and harm to themselves and remove NJIT from the responsible parties before the event starts. In order to fix it, we had to bargain with the office of student life and also talk to each performer and have them sign the forms and contact their insurances before everything was cleared to start.

I had that happen to me when I was working in the consumer sector, I was reforming out of a ester that is now discontinued, it was believed that it was going to be a very simple reform of a popular tanning lotion, we make a batch of the tanning lotion then put it on stability, and it was believed that we were going to have passing results, since it incorporated less the 1 percent of the overall mixture, so as a result the packaging department contacted suppliers and mass produced the new packaging that removed this ester early on in its labeling. A week goes by, while the lotion is in the stability, we notice that the lotion completely failed stability with a complete separation of the emulsion, like I said before it was believed to be a very simple reform and this was not expected, a month later and probably 15 different test batches, we were able to stablize the product for production with the label specific raw materials, if we had not been able the resolve this issue within the month time frame that upper level management gave us, we would have lost alot of money from the packaging alone. Listen learned... ensure that formula is stable before mass producing packaging with specified ingredient list.

Chris

The company that I currently work for is notorious for unexpected issues that move "extraneous tasks" onto the critical path. One recent example was in the production of a prototype gel pad. The prototype was commissioned as a special request (outside our current product offering) for a customer's clinical trials. Upon completion and approval of the formulation and the manufacturing and packing procedures, production was in full swing. The "extraneous task" that found its way onto our critical path was an issue with the label that was being used to seal the final product in its production mold. As per the customer's regulations, every prototype gel pad required a specific label to comply with certain Unique Device Identification regulations. The issue turned out to be significant as the heat sealing equipment caused the ink to warp and distort serial numbers on the seal. As such, production was ground to a halt until the seals could be properly treated to prevent the label from being distorted. Fortunately, the issue only resulted in the loss of a single day for our production team. However, this single day resulted in staff and resources being directed away from other tasks and production.

Most of us have experienced a critical path situation during the senior design capstone project. We were designing a product that monitors blood glucose, heart rate and activity that securely transfers data to a remote server. All the data is posted on an UI, which is accessible to family members and doctors. We talked to few professors within the CS department at NJIT and it was thought that getting access to NJIT free server was an easy task. However, as the project continued, we realized that server used an HTTPS (secure protocol). On the other hand, our hardware (Arduino) was only compatible with HTTP protocol. The devil’s in the details was important and something so simple became our critical path for the project. We did not check the compatibility of two pieces of equipment and as a result ended up reevaluating our options of hardware.

Hello,

There was one time that my team had placed leads in certain places of torso, legs and ankles in order to track the leads using a tracking program. The purpose of this was to collect data in order to analyze and try to maximize the degrees of freedoms in hip prosthetic joints. The team had originally planned to put leads around the leg and we were supposed to invest one day collecting data from different position (walking, sleeping and sitting). After we obtained the data, the leads were being confused by the program which caused us to get very inaccurate data. However the following day we worked it by using rigid bodies which not only provide a tracking of multiple leads but also lets us obtain the orientation of the muscle it is placed on. Although we got behind schedule we got to continue with the critical path and finished on time.

Sincerely,
Roberto Pineda.