Stove Project

Cardboard Models

This week we were tasked at looking at new ways to design a coal burning stove. After looking at some considerations such as efficiency, cost, safety, insulation, and adaptability we split into groups to brainstorm potential stove designs. My group knew we wanted to safety to be a number one priority so we focused mostly on a system of ventilation, as well as considered a sunken cook-top to prevent burns and spills. We created a stove with an inner chamber for the fuel to rest and ran a chimney out of that chamber. Around that chamber we wanted an insulating material such as clay that is cheap and effective. The cook surface rests directly above the chamber. There is two doors (an outer door and an inner door) that you use to access the fuel. The two doors provide a safer chamber. The downside of our design is that we didn't put enough consideration into the air flow to get to the heat. In talking with the class we thought making the bottom of the stove more of a grate so that air could flow in and up through the bottom would be the best next step in the prototyping. In making our cardboard model I feel more familiar with the general parts of the cook-stove and I'm interested to delve further into exploration to the best coal burning stove.

Estimating Weight to Power LED Bulb for 30 Minutes

Assumptions:

-LED= .02Amps

-Gravity is 9.8m/s^2

-Not accounting for wind or other resistance

- Dropping weight from 2 meters

-Powered by 9V battery

1. How many Joules to needed to power for 30 minutes

Watts= J/s

.02A*9V=.18 Watts

.18W=J/(30min*60sec)

.18W=J/1800s

J=324

2. How much weight to create 324 J work

J=kg(m/s^2)

324=mass((9.8m/s^2)*2m)

mass=16.5kg

Time Management Reflection

This past week we had two substantial projects and subsequent blog posts all due on the same day. There are really two scenarios of how it could have gone--the projects could have been spaced out over no time with out a lot of stress in trying to complete before the deadline...OR there could have been a lot of last minute stress in trying to finish an unreasonable amount all at once. I would say I attempted to space out the projects and was very successful in getting the sharps project done in time but the lantern proved much more difficult. Working in a group for the sharps container made it easier to be more accountable to sticking to a good schedule. We finished that in a few out of class sessions. The lantern I unfortunately left until a little bit late to get started on. It was a complete stay-up-all-night cram to finish but I wouldn't say it didn't come with some stress. Next time, I'd really want to aim at getting the physical project started much sooner because I spent too much time visualizing without realizing that building something takes a lot more time than you think. The trial and error and adjustments that need to get made are plentiful and deserve several long out of class sessions spaced out over time to get a quality finished product.

Lighting Reflection

In class we were asked to work on a paper quiz in pure candle light with a group to crack some estimation problems. This was extremely challenging for more reasons than the obvious ones. Besides it just being really difficult to see our work it also made it hard to concentrate, to communicate, and to stay engaged in what we were doing. Because we couldn't really see each other's faces we couldn't rely on any non verbal communication through body language or hand gestures so in order to be fully present I felt I had to especially tune-in which required much more energy than usual. Concentrating was hard because of the amount of effort (and headache) it took to try and read the paper. I was much more prone to zone off around the room instead of focusing on my work. When were allowed to use the lanterns it was much, much easier to complete the tasks at hand. The questions seemed less daunting and much clearer. Even with the lanterns, the lighting certainly wasn't ideal but much an improvement. It was very enlightening (no pun intended) to do this exercise. It really shows how inefficient it is to work with by candle light at night (not to mention the cost of candles over time!).

Lantern Reflection

The lantern project proved a lot harder than I thought it would be. Having done a similar circuit project before, I made the fatal mistake of assuming this project would be a breeze. The first place I went wrong was by jumping right into the building before drawing my circuit diagram. Doing such a simple thing literally could have saved hours because I was just not able to visualize the switch until I drew diagrams for myself. Eventually after spending frustrating time in the lab I decided to take a break and clear my head. I sat down, drew the circuit diagrams and immediately felt like a fool for how I was trying to set it up! Lesson learned. Below are my circuit and design diagrams as well as resistance calculations which I did before starting the project.





My design is a simple hand-held lantern using an old soda can to help reflect the light. The soda tab acts as a  hanging device for the lantern and I used a recycled shoelace to string it. This design is also nice because it hides the batteries and wires in the base of the lantern so that they don't clutter up the finished design and the light reflects off of the scrap foil. I've created a simple switch out of brass brads and used a paper clip to connect or disconnect the circuit. The good thing about this switch is that is doesn't require someone to hold it down all the time it can just stay on for hands free illumination. Below are pictures of the finished product.

I envision my lantern as a good one to have for doing school work late at night, around the dinner table, or hung and used as a reading lamp by a bed or chair. The lantern works great for resting, hands free illumination. The potential downside to my design, however is that it wouldn't work well as a "flashlight"or for focused illumination--it is more for a rounder, more distributed light.


UPDATE: As soon as I got to class, settled down and threw my switch on I found my lantern only dimly lighting and then soon it totally stopped lighting. Oy. This was insanely frustration. I spent the class wondering what could have gone wrong in the 18 hours since I had last tested the lantern. After class it took only 45 seconds to figure out that one of the wires had been jostled out of place. I got it fully working again of course after the class and demonstration was over. The lesson here is to test more for durability and try and find weak points to preemptively reinforce before finishing the product!

Sharps Container Reflection

Looking at the design process from start to finish during this project was a great introduction to engineering. Working in a group was very important for this project because of how easy it was for us to all riff off of each others ideas and add/improve them. Starting on the very first day of class when we formed groups with students we had never met we launched into brainstorming and problem solving together.

We started by going down a couple of different directions--destroying the blade vs. safely storing the blade vs. improved blade removal methods. We thought of everything from special gloves to using acid to dissolve the blades. We started by choosing a few ideas we really liked and weighed options using cost, effectiveness, effort, and rate of disposal to determine the best route to take. We decided on a widely improved box that is both safer and more user friendly than the existing sharps container.

We ultimately decided on a solid outer box that contained a removable inner bag for disposal. We wanted a thick but reusable material for the inner bag so it could be safely emptied in a disposal area. The cardboard outer box acts as a fail safe and will contain any stray blades safely. We noticed that it is difficult and somewhat dangerous to remove the lid on the sharps disposal container currently in the lab so we wanted to make sure removal was easy and gentle while also keeping the sharps safe and secure while in the box. We built a solid outer cardboard box out of recycled material and then began brainstorming what we could use for the inner bag. We thought of using denim but could not find any. One of the people in my group had some felt and a sewing kit so we did some experimentation with the sharps to see how easily it could cut or poke through the felt. As it turns out, felt is extremely durable to sharp objects. It's also lightweight and cheap for any replacement bags in the future. We sewed up a bag and made sure it could fasten shut using velcro for when you lift it from the box and take it to the disposal area (so that sharp are contained within the bag during transport). We made sure the bag was stable within the box using velcro to fasten it to the walls of the box--this keeps it open and supported while also removable when needed. The last component of the box itself is a removable heavy-duty mesh wire with openings just wide enough to let a sharp in when angled correctly but not wide enough for a sharp turned horizontally. The purpose of this gridded layer is to keep sharps from escaping the box if it were to get jostled around (ie. lets sharps in, keeps sharps in). This layer is removable when retrieving the bag out of the box for disposal. Finally we put the lid on with a small hole and we had a completed box!

Inside the box:

Close up view of velcro:

Finished box--outer view:

We also wanted to call to attention the dangerous materials inside the box so we made sure to mark it as a dangerous item and that it contains sharp materials. Because you cannot see inside of the box, and therefore can't know when it is full, we brainstormed ways to know when to empty the inner bag. We decided on a tally system where people check a box every time they dispose of a sharp inside the box. When the 30th box gets checked, there is instructions to remove the bag and reset to the next page of empty boxes. This also calls attention to the task at hand and adds another action for the person disposing of the sharps to be aware of which in-turn brings more overall awareness to the task at hand leading to an ultimately safer and easier disposal mechanism.

The project went really well and group-work was what made this come to life. Communicating well, finding time outside of class, supportive attitudes, and open-mindedness were key to the success of this project!

Keychain Reflection

Designing and crafting a small aluminum keychain in class was a great way to learn the safety and procedures of using machines as well as learn how different the desired outcome can be from the actual outcome. To start, I'll go over the safety rules of working in the engineering lab and with the machines.

General
1. Appropriate gear
-Always be wearing supportive, closed toed shoes in the lab. Additionally, keep your hair neatly tied back and don't wear loose clothing. You'll also need safety glasses in the lab at all times.
2. Always be with someone
-Though we are privileged to access the room at all hours--even after class, it is vital observe the same safety procedures as you would during class hours. This means no working on projects without another person in the room who is willing and able to call for help and assist you in the case of an emergency.
3. Always ask if you are unsure!
-Better safe than sorry. Never use a piece of equipment unless you are entirely comfortable with it. Ask Professor Banzaert or Larry Knowles the machinist about any questions or concerns you have in the lab.

Drill Press
When using the drill press, remember to have hair tied back and no loose clothing. The spinning motion of the drill bit can suck in any extraneous articles. Firstly, you need to make sure you are using the correct drill bit for the project you are working on. Choose based on size of hole and material you are drilling through. Also, when tightening the bit into the chuck, make sure the channel for waste material is clear on the bit so that material doesn't jam the equipment as it escapes. Now you will place your material on the press and center it where you want the hole to be. There is a handy laser that will help you aline the drill with the desired area. Additionally you can gently rotate the handle and press the bit to the material to see if it matches up. When drilling you should never use your hands to secure your material. Always use a clamp or vise to fasten your material to the table. When aligning the drill with your hole, make sure to have the drill centered over the hole in the table so that you do not damage the bit or the table when drilling. Now you are ready to drill. Turn the machine on, lower the drill and make subtle up and down motions as you push the drill through the material. Once you have made it all the way through, gently pull the drill up and turn the machine off. Wait until the bit stops spinning completely before retrieving your object from the table.

Bandsaw
Again, when using the bandsaw, adhere to all general safety rules and be sure to wear safety goggles. When adjusting the height of the blade make sure there are always at least three notches from the blade above the table. You should avoid making the height of the saw too tall because it makes the blade less stable and can be more dangerous to operate because there is more potential area of exposed blade to injure yourself on. Once you have adjusted the height of your blade using the knobs in the back of the machine you should examine your material and what kind of cut you need to make. If you have a long piece of material you should have a friend help out by holding the part of it that extends off the table to stabilize it. When using the bandsaw it is important that your fingers are never within a dangerous distance from the blade. Always use either a push stick or a vise or a combination to guide the material through the blades. Once you turn the machine on do not force through the blades with a ton of pressure, simply ease it though and be careful at the end so that you do not fall into the machine because of your momentum. Remove the material completely from the blades and turn the machine off. Wait for the blade to come to a full stop and remember that the material will be hot (because of the friction) so use a push stick to drop it into some water to cool it down if it's metal. If it's wood simply let it cool for a moment before picking it up.

There are limitations and benefits to each machine. For example, the drill press is great because it works with almost every material and thickness. However, there is a limit to the size and shape you can drill into your material. You can't drill a square for example. The drill press is also very precise when used properly. The bandsaw on the other hand is very challenging to get precise cuts unless you have significant experience with the machine. The bandsaw is good for removing larger amounts of material but is generally constricted to straight or only slightly curved lines. Curvy, intricate designs are not possible using this machine.

My experience with the machines during the project was enlightening. I had envisioned a lightening bolt shape and my keychain ended up taking a similar form (though not exact) of what I had imagined. When using the bandsaw I found it hard to control the direction of the cut--it was as if the blade steered itself and in order to get the desired cut I really had to focus on guiding it properly. The drill press was a little easier for me. With the right set up the hole was fairly straight forward to make and went right in the spot I wanted it to. The exact shape of the lightening bolt came out a little skewed from the original lines but it still very much resembled what I was envisioning. Because I had to make some detailed cuts, I ended up with a few odd and jagged inner and outer edges. Using a both the sanding belt and a hand-operated triangular file, I was able to sand away any imperfections remaining.

Poor People's Energy Outlook Reading Reponse

Over the course of the reading I found myself shocked at how limited electricity is worldwide. 17% of the world population had no access to electricity in 2010! Of course as the reading explains this number could be vastly miscalculated based on poor data collecting techniques--this surprised me a lot as well. I had assumed that whatever methods we've been using to collect counts and data on this crucial topic have been carefully vetted and very reliable. In reality much of what we know about energy accessibility among other issues is a mere estimation. Something else that this reading shed light on for me is that low income families can generally still accomplish--at least somewhat--the necessary tasks to survive (such as cooking, heating, lighting) but the levels of work, waste, and danger involved are the real evils of not having access to clean energy. It is startling that 4.3 million people die every year from indoor pollution. I didn't even know indoor pollution was a problem let alone fatal on such a scope of magnitude.

I'm very curious to see how the implementation of SE4ALL as outlined in the reading pans out over the next 15 years. I wonder how different counties will fail or succeed in implementation based on their political motivation and financial resources.  It seems energy is one of the most crucial pillars of development and that improvements in accessibility will not only help families on an individual level but also benefit the "business ecosystem" and help sustain communities on a broader scale. Hopefully governments and NGOs can get past the immediate financial commitment in realizing that in the long term, energy access will ultimately save countries exorbitant amounts of money made up in commerce and the welfare of their citizens.

An Introduction!

Hello! My name is Eva Duckler and I'm a first year at Wellesley College! While I haven't committed to a major yet and I'm interested in an array of subject areas, I am particularly curious to explore art history as a potential major. I also love plants and permaculture so I hope to push on those subjects more while I'm here as well. I'm taking engineering 120 because it seems like a really hands on way to dig into mathematics and engineering as well as tap into the broader issues and possible solutions surrounding underserved communities. I'm excited to follow the process of creating technologies from conception through design, prototyping, testing until we've accomplished building a functioning device. I'm specifically interested in learning more about Biomass, a method to turn unused plant matter and animal waste into fuel. Like most technologies, Biomass comes with downsides and lots of potential unknowns but I believe that with more research and careful testing and data collecting periods Biomass could become one of the most relevant energy sources for a sustainable future. To learn more about Biomass and its weighed risks click here. I'm looking forward to the semester and all of the exploration to come!