Engineering design projects in my MIT undergraduate and graduate curriculum.

1. Claudia Maritza
Espinoza
Engineering Design Portfolio
Massachusetts Institute of Technology
Department of Civil & Environmental Engineering
(860) 490-5841 | cme88@mit.edu

2. Table of Contents
Class Title Page
1.101 - Floating Islands 1-2
1.102 - Micro-hydro Generator 3-4
1.107 - Arsenic Sorption of Biosand Filters 5-6
1.106 - Flow Rate of Muddy River 7-8
- Diffusivity Coefficient of Tannic Acid 9 - 10
1.103 - Rooftop Farms 11 - 12
- Bamboo Bridge 13 - 14
UROP - Mussel Feeding 15 - 16

3. Table of Contents
Class Title Page
n/a - Kosim Water Keg 17 - 18
MEng - Kanchan Arsenic Filter 19 - 20

4. Floating Islands
1.101, Fall 2007
1

5. This project aimed to redesign the Back Bay area of Boston,
MA in order to accommodate a greater & modern society.
Approach: Final Design Model
To expand the commercial area of the
Back Bay by opening up the Charles
River basin and incorporating
“floating islands” of recreational
buildings.
Teaching Component:
Designed an apparatus that will
demonstrate the effect of
hydrostatics and restoring forces on
a floating structure.
2

6. Micro-Hydro Generator
1.102, Spring 2008
3

7. The objective of this project was to use the kinetic energy of
water flow, through municipal pipelines, as a power source
for remote water quality meters.
Approach: Final Design Model
Develop a turbine and micro-hydro
generator system to transfer energy from
the pumping station to a pH sensor.
Implementation:
Using a transformer and a flow rate of 40
gal/min, we obtained a voltage of 400 mV
from our turbine hydro-generator.
Role: Lead designer (KeyCreator CAD
model)
4

8. Arsenic Sorption of
Biosand Filters
1.107, Spring 2009
5

9. This study investigated the arsenic sorption capacity of sand
conditioned with iron nails in the presence of several ion
species prevalent in Bangladeshi groundwater.
Approach:
Assess the effectiveness of filter conditioning Results
through the formation of hydrous ferric
oxyhydroxides (HFOs) as potential sorption sites
for arsenic ions. BGW +20
mg/L [Si}
Determine whether phosphorus [P] and silica [Si] 0.5 mg/L [As] control
lower the partitioning coefficient of arsenic in
artificial Bangladeshi groundwater (BGW).
Implementation:
Nepali nails were soaked with clean concrete sand BGW + 3 mg/L [P]
for 24 hours. Conditioned sand was shaken with
BGW, As, P and Si solution for 10 minutes and let
it sit for 5 min. 0.5 mg/L [As] control
Samples were measured using Perkin Elmer
inductively coupled plasma optical emission
spectroscopy ( ICP- OES).
6

10. Muddy River Flow rate
1.106, Fall 2009
7

11. The objective was to develop an experimental method
to estimate the volumetric flow rate of the Muddy River,
Q [m3s-1].
Approach:
The flow rate mid-depth and at the center of the
river would be measured to minimize the influences
of external factors (i.e. high surface velocities due to
wind).
Also, since entering the river was not permitted, the
design incorporated a mechanism that floats beneath
the surface and takes advantage of the bridges near
the Museum of Fine Arts (MFA).
Implementation :
Using a fishing float and weights, we measured the
time it would take for the float to reach one side of
the bridge to the other.
Results Mean Velocity [ms-1]:
0.33 +/- 0.03
We also measured the length and width of the bridge, Area [m2]:
as well as the depth of the river, from the mid-point 3.0 +/- 0.3
of the bridge, to estimate the cross-sectional area of
Vol. Flow rate [m3s-1]:
the river and the distance the float traveled. 1.0 +/- 0.1
8

12. diffusion coefficient
of tannic acid
1.106, Fall 2009
9

13. The objective was to design and execute an experiment that
will most accurately estimate the molecular diffusion
coefficient of tannic acid in water, Dm = O(10^-6 cm/s).
Approach:
To isolate molecular diffusion of tannic acid from
tea bags from turbulent diffusion of mixing and
density properties of tea water.
Lipton natural black tea (hot brewed) was used
for its 9.61 +/- 0.3% content of tannin acid per tea
bag (Amin, 1997). Results
Dm = 5x10-6 [cm2/s] +/- 2x10-6 [cm2/s]
Implementation:
Tea bags were pre-wetted and placed in the lid of (dz^2 vs. t) for the pre-wetted
teabag vessel
a glass vessel. Vessel were completely filled with 3
distance squared
water, sealed with a lid and gently flipped over 2.5
2
y = 9E-06x - 0.253
R2 = 0.9688
(cm^2)
upside down. 1.5
1
Once the tea concentration was fully mixed across 0.5
the cross-section of the vessel, the vertical rise of 0
0 50000 100000 150000 200000 250000 300000 350000
-0.5
the tea, due to molecular diffusion, could be time (sec)
observed.
Reference: Amin Alaa S. (1997). Utilization of Tetrazolium Blue for Colorimetric Assay of Tannins in Tea. Mikronchim. Acta 126, 105-108. 10

14. rooftop farming
1.103, Spring 2010
11

15. This project aimed at designing a innovative vertical
farm.
Approach: Final
Design modular and easily transportable rooftop
farms:
Design
- Easily customized for customer to create Model
unique farm
- Appealing to our customers, commercial
grocery stores in New England
Research and Testing:
Module Structure: compact design, adjustable for
different systems, storage
Compatible production system: hydroponics,
aquaponics, decomposition, soil-based crops
Energy usage & financial feasibility
Role: Head designer for production system (Google
Sketch-up models)
12

16. bamboo footbridge
1.103, Spring 2010
13

17. The footbridge of design was intended to build a pass way
over a ditch that connects the roadside to a social enterprise
ceramic filter factory in Taha, Ghana.
Approach:
Building & Testing
Design a footbridge that was feasible in Ghana:
- Easy and quick to assemble
- Mobil and/or foldable
- Uses local materials of Ghana
- Applicable over flood levels of Ghanian storms
- Aesthetically pleasing
Implementation:
2 ‘ x 12 ‘ spam, cable stayed bridge made from
bamboo, jute rope and metal chain
Bridge must withstand a testing weight of 1 ton
( 2,000 lb)
Role: Conducted hydraulic analysis of flood
flows by the ditch, near the set location of bridge
14

18. Mussel Feeding: Evaluating Toxic
Levels of Organic Chemicals in Sediment
Undergraduate Research Opportunity Program:
Ralph M. Parsons Lab, Gschwend group
May 2009 - December 2009
15

19. Researched and designed experiments to develop an effective
method for the toxic evaluation of hydrophobic organic compound
(HOC) mixtures in sediment.
Approach: Results
Measure high concentrations of HOC mixtures % Feeding Rate Reduction
though the toxic effect of narcosis in Mytilus edulis
(blue mussels).
The sub-lethal effect of narcosis in mussels can be
measured through a decrease in feeding rate,
quantified through the fluorescence of algal
concentration in solution. Text
[Phenanthrene] (ug/L)
[Phen] extracted from LDPE bottle
Implementation: 12
over time (1 hour)
Mussels fed in different concentrations of 10
[Phen] (ug/L)
phenanthrene solution in artificial seawater. 8
Throughout feeding, 2 mL of solution is pipetted and 6
read for fluorescence units, calibrated for chloroform 4
(algal mass) and phenanthrene concentration. 2
0
Buffering systems to stabilize exposed toxicant 0.0 0.2 0.4 0.6 0.8 1.0 1.2
Time (hours)
concentration were researched (“spiked” LDPE bottles).
Bottle 3 Bottle 4 Bottle 5 Bottle 6
16

20. Kosim Water Keg: Ceramic Water
Filter System Study in Tamale, Ghana
In collaboration with:
Pure Home Water
Susan Murcott (MIT, Senior Lecturer of the Department of Civil & Environmental Engineering)
Christopher R. Schulz (Senior VP of Camp, Dresser & McKee)
June 2010 - August 2010
!
17

21. Researched a new ceramic water filter model for the potential
marketing and development in northern Ghana.
!
Approach:
The KWK filter system is a made of two traditional
“flowerpot-shaped” ceramic filter elements. In
contrast to the standard ceramic pot filter, the KWK
filters water from the outside to the inside of the
system, and it also included a siphon pump to
remove filtered water safely stored inside the keg.
This designed aimed at increasing the filtration flow
Text
!
!
rate and at reducing the recontamination of
pathogen free water. Results
• Microbial and turbidity removal: KWK did
not perform as well as the standard ceramic
Implementation: filter.
Conducted on-site water quality testing including: • Flow rate: the KWK rates were higher by a
bacterial removal, turbidity removal and flow rate factor of 3 or 4 in the first 2 hours, which is
appealing to local community members.
measurements of the KWK filters. Also, documented
• The KWK construction may have weakened
the production of the ceramic elements and
the pots and led to poor microbial and
contributed to filter design alterations. Furthermore, turbidity removal performance.
evaluated the production, costs and social feasibility •A re-design of the KWK to strengthen the
of deployment through demonstration gatherings in filter system and include local materials is
local rural communities. recommended.
18

22. Kanchan Arsenic Filter:
M.Eng. Thesis Study in Nepal
In collaboration with:
Maclyn O’Donnell
Environment and Public Health Organization (ENPHO); Kathmandu, Nepal
September 2010 - June 2011
19

23. Researched the arsenic removing performance of the KAF under
different groundwater chemical compositions of rural Nepal.
Approach:
Groundwater arsenic contamination
Results
is a recognized problem in many #!!"
'#!"
areas of South Asia. However, the
!"#$%&'()*%'$%+",-*%(./0123(
'!!"
uncertain performance of the KAF &#!"
under various water quality &!!"
%#!"
conditions has limited the %!!"
distribution of the KAF outside of $#!"
Nepal. Our study focused on assessing the effect of various $!!"
groundwater chemical parameters on the arsenic removal Text #!"
!"
performance of the KAF. $" $$" %$" &$" '$" #$" ($"
4&5+$"(6$7$",%'$(89:;$"(
)$" *$" +$" $!$"
<"*9%=(>,+$"( 4&5+$"(?9+5$+(
• Tested 101 filtered water and 77 groundwater
Implementation: samples in 15 different villages.
Conducted on-site water quality testing for the inlet • Concluded that the KAF will not perform
groundwater source and the outlet filtered water for the well in groundwater conditions that do not
following parameters: promote iron corrosion.
• Poor performance indicators: GW As > 200
•Arsenic •pH •Manganese ug/L; Nail Fe(II) < 1.1 mg/L; GW Chloride < 7
•Ferrous Iron •Dissolved Oxygen •Flow rate mg/L; low GW Hardness; high GW pH.
•Phosphate •Chloride •Filter age • Next Steps: incorporating local components
•Silica/Silicate •Electrical •Location into the KAF system to increase iron
•Hardness (CaCO3) Conductivity •User survey corrosion.
GW = groundwater
20