MIT Engineering Design Portfolio

Claudia Maritza Espinoza

Massachusetts Institute of TechnologyDepartment of Civil & Environmental Engineering (860) 490-5841 | [email protected]

Engineering Design Portfolio

Table of Contents

1.101 - Floating Islands1.102 - Micro-hydro Generator1.107 - Arsenic Sorption of Biosand Filters1.106 - Flow Rate of Muddy River

- Diffusivity Coefficient of Tannic Acid1.103 - Rooftop Farms

- Bamboo BridgeUROP - Mussel Feeding

1 - 23 - 45 - 67 - 8

9 - 1011 - 1213 - 1415 - 16

Class Title Page

Table of Contents

n/a - Kosim Water KegMEng - Kanchan Arsenic Filter

17 - 1819 - 20

Class Title Page

Floating Islands

1.101, Fall 2007

1

This project aimed to redesign the Back Bay area of Boston, MA in order to accommodate a greater & modern society.

Approach:To expand the commercial area of theBack Bay by opening up the CharlesRiver 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.

Final Design Model

2

Micro-Hydro Generator

1.102, Spring 2008

3

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: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)

Final Design Model

4

Arsenic Sorption of Biosand Filters

1.107, Spring 2009

5

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 through the formation of hydrous ferric oxyhydroxides (HFOs) as potential sorption sites for arsenic ions.

Determine whether phosphorus [P] and silica [Si] lower the partitioning coefficient of arsenic in artificial Bangladeshi groundwater (BGW).

Implementation:Nepali nails were soaked with clean concrete sand for 24 hours. Conditioned sand was shaken with BGW, As, P and Si solution for 10 minutes and let it sit for 5 min.

Samples were measured using Perkin Elmer inductively coupled plasma optical emission spectroscopy ( ICP- OES).

Results

BGW + 3 mg/L [P]

0.5 mg/L [As] control

BGW +20 mg/L [Si}

0.5 mg/L [As] control

6

Muddy River Flow rate

1.106, Fall 2009

7

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.

We also measured the length and width of the bridge, as well as the depth of the river, from the mid-point of the bridge, to estimate the cross-sectional area of the river and the distance the float traveled.

Mean Velocity [ms-1]:0.33 +/- 0.03

Area [m2]: 3.0 +/- 0.3

Vol. Flow rate [m3s-1]:1.0 +/- 0.1

Results

8

diffusion coefficient of tannic acid

1.106, Fall 2009

9

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).

Reference: Amin Alaa S. (1997). Utilization of Tetrazolium Blue for Colorimetric Assay of Tannins in Tea. Mikronchim. Acta 126, 105-108.

Dm = 5x10-6 [cm2/s] +/- 2x10-6 [cm2/s]Implementation: Tea bags were pre-wetted and placed in the lid of a glass vessel. Vessel were completely filled with water, sealed with a lid and gently flipped over upside down.

Once the tea concentration was fully mixed across the cross-section of the vessel, the vertical rise of the tea, due to molecular diffusion, could be observed.

Results

(dz^2 vs. t) for the pre-wetted teabag vessel

y = 9E-06x - 0.253

R2 = 0.9688

-0.5

0

0.5

1

1.5

2

2.5

3

0 50000 100000 150000 200000 250000 300000 350000

time (sec)

dis

tan

ce s

qu

are

d

(cm

^2

)

10

rooftop farming

1.103, Spring 2010

11

Approach:Design modular and easily transportable rooftop farms:

- Easily customized for customer to create 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)

This project aimed at designing a innovative vertical farm.

Final Design Model

12

bamboo footbridge

1.103, Spring 2010

13

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:

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

Building & Testing

14

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

Text

Researched and designed experiments to develop an effective method for the toxic evaluation of hydrophobic organic compound (HOC) mixtures in sediment.

Approach:Measure high concentrations of HOC mixtures 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.

Implementation: Mussels fed in different concentrations of phenanthrene solution in artificial seawater. Throughout feeding, 2 mL of solution is pipetted and read for fluorescence units, calibrated for chloroform (algal mass) and phenanthrene concentration.

Buffering systems to stabilize exposed toxicant concentration were researched (“spiked” LDPE bottles).

Results

[Phen] extracted from LDPE bottle over time (1 hour)

0

2

4

6

8

10

12

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Time (hours)

[Ph

en

] (u

g/

L)

Bottle 3 Bottle 4 Bottle 5 Bottle 6

[Phenanthrene] (ug/L)

% Feeding Rate Reduction

16

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

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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 rate and at reducing the recontamination of pathogen free water.

Implementation: Conducted on-site water quality testing including: bacterial removal, turbidity removal and flow rate measurements of the KWK filters. Also, documented the production of the ceramic elements and contributed to filter design alterations. Furthermore, evaluated the production, costs and social feasibility of deployment through demonstration gatherings in local rural communities.

Results

18

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• Microbial and turbidity removal: KWK did not perform as well as the standard ceramic filter.

• Flow rate: the KWK rates were higher by a factor of 3 or 4 in the first 2 hours, which is appealing to local community members.

• The KWK construction may have weakened the pots and led to poor microbial and turbidity removal performance.

•A re-design of the KWK to strengthen the filter system and include local materials is recommended.

Kanchan Arsenic Filter: M.Eng. Thesis Study in Nepal

In collaboration with:Maclyn O’Donnell

Environment and Public Health Organization (ENPHO); Kathmandu, NepalSeptember 2010 - June 2011

19

Text

Researched the arsenic removing performance of the KAF under different groundwater chemical compositions of rural Nepal.

Approach:Groundwater arsenic contamination is a recognized problem in many areas of South Asia. However, the uncertain performance of the KAF under various water quality conditions has limited the distribution of the KAF outside of

Implementation: Conducted on-site water quality testing for the inlet groundwater source and the outlet filtered water for the following parameters:

Results

20

• Tested 101 filtered water and 77 groundwater samples in 15 different villages.

• Concluded that the KAF will not perform well in groundwater conditions that do not promote iron corrosion.

• Poor performance indicators: GW As > 200 ug/L; Nail Fe(II) < 1.1 mg/L; GW Chloride < 7 mg/L; low GW Hardness; high GW pH.

• Next Steps: incorporating local components into the KAF system to increase iron corrosion.

•Arsenic•Ferrous Iron•Phosphate•Silica/Silicate•Hardness (CaCO3)

•pH•Dissolved Oxygen•Chloride•Electrical Conductivity

•Manganese•Flow rate•Filter age•Location•User survey

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Nepal. Our study focused on assessing the effect of various groundwater chemical parameters on the arsenic removal performance of the KAF.