Engineering and Design Portfolio

Alexander HourietBS Mechanical Engineering, 2020MS Bioengineering, 2021Swanson School of EngineeringUniversity of Pittsburgh

ach75@pitt.edu267-615-4576

OneBrace Resistance Trainer

Goal: Create a device that allows users to safely regain leg muscle strength during postoperative physical therapy

Purpose: It is very important to regain range of motion and strength as quickly as possible post-surgery, but it must be done in a very safe and controlled manner.

Master’s Degree Capstone Project

Features● 3 part housing

○ Top cap takes end of clock spring

○ Middle section has teeth to lock spring in place

○ bottom has central post through all components, notch for center of clock spring

● Top and middle move together during exercise

● The tighter the spring is wound while the leg is at rest, the more resistance the trainer provides

● Trainer is able to universally fit on any brace or can be worn on its own

Mainstream Smart Home Demonstration Station

Goal: Create a way to easily show off the differences between Google, Apple, Amazon, and Samsung Smart Home Ecosystems

Purpose: Each system has its pros and cons, this system allows a user to experience them without a lengthy install in their home or reading about the differences

Research project part of a NIDLIRR grant to develop a service delivery model for mainstream smart home technology in the homes of persons with disabilities

Features● Fully functional consumer

light switches and outlets● Smart blinds and curtains,

smart door lock● Functioning thermostat ● Folding form factor fits in a

standard suitcase

Concept taken from idea to CAD to a physical device

Design of a System to Test Anterior Cruciate Ligament Failure

Goal: Create a device that reproduces in vivo mimicking ACL tears in cadaver legs during a jump landing scenario

Purpose: To create accurate ACL tears to allow study of the injury mechanism and surgeons the opportunity to test new surgical techniques

Senior Design Project

Some aspects of our project included:1. Design of a pneumatic system to

tension Quadriceps and hamstring tendons

2. Developing in vivo-accurate tension cable lines of action

3. Designing for adaptability of all possible leg sizes using slotted attachments and set screws

4. Upgrading cable attachment methods from existing device to increase pneumatic cylinder life

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Design of an Enhanced Tubing Connector for ECMO Circuits

Goal: Create a new connector that decreases the risk of clotting in extracorporeal membrane oxygenation circuits

Purpose: The standard connector used is a M-M connector that increases turbulent flow within the tubing, leading to a higher risk of blood clots. Blood clots in an ECMO circuit lead to almost certain death in a patient.

Designed as a graduate class project for Cardio Organ Replacement

Features● F-M connection style does not

disrupt flow on the entrance side

● Spiral lock makes tubing easy to insert and stay in place

● Gradual change in cross section provides better flow transition

Design of a Single-Sensor Device to Calculate Surface Area of Complex Objects

Goal: Develop a system to measure the surface area of complex objects that costs less than $100

Purpose: Create a cheap solution that is still accurate to calculate the surface area of an object to be used for further property analysis (i.e. thermal coefficients, drag, etc.)

Designed for a class project in Mechanical Measurements II

This device featured two stepper motors located at 1 and 2 and an infrared distance sensor located at 3. Every time the stepper motor at 1 would step, the sensor would record a distance. After 1 full revolution is completed, the motor at 2 would step, rotating the power screw and raising the sensor. This device is powered by an Arduino, and feeds data into Matlab. Unfortunately due to the COVID-19 Pandemic, the physical device progress ended after the form factor prototype.

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The software for this device functioned by compiling the distance values received from the sensor in Matlab. The points were processed in a cylindrical coordinate system based on the distance reading, angle in the revolution, and height of the sensor then plotted as a point cloud. This point cloud is converted into a surface mesh using Delaunay Triangulation, then the surface area of the triangles is calculated. The final output is a representation of the object that was scanned, with the surface area value displayed next to it.

Design of a Proximity Sensor Security System

Goal: Using Arduinos, create a home security system

Purpose: To gain experience using the Arduino IDE in more complicated use cases and experiment with radio communication

Personal Project

This system has two main parts: A receiver module and three identical transmitter modules. All boards communicate wirelessly using low range radio chips and are battery powered.

Once the transmitters are set in their desired location, they constantly poll for distance from the sensor. When a change in distance is registered, it sends an alert to the receiver module, lighting up the LED corresponding to that sensor that has been triggered.

Receiver Module Transmitter Module

Radio

IR Distance SensorAlert LEDs

Design of a Fully Mechanical Timer

Goal: Create a timer that can accurately time up to 5 minutes, at 30 second intervals

Purpose: To use the mechanical actions studied in the class in a system that functions as designed

Designed for a class project in Mechanical Design II

This system was powered by a falling mass spooled around a shaft that is resisted by a variable inertia value. When the satellite masses are set further from the rotating shaft, the inertia will be higher, and the mass will fall slower. The four satellite masses are held in place on the perpendicular shafts using two nuts, so the correct corresponding distance to the time goal can be set before a test is run. Unfortunately due to the COVID-19 Pandemic, the project goal shifted from a physical timer to purely theoretical.

Time (s)Linear Velocity (m/s)

Angular Velocity (rad/s)

Required Inertia (kgm2)

Set Length From Rod (cm)

30 0.0508 4 0.062 6.360 0.0254 2 0.125 1490 0.0169 1.33 0.187 18.7

120 0.0127 1 0.249 22.5150 0.0102 0.8 0.311 25.7180 0.0085 0.67 0.374 28.6210 0.0073 0.57 0.436 31.2240 0.0064 0.5 0.498 33.6270 0.0056 0.44 0.561 35.9300 0.0051 0.4 0.623 38

PASTEBRUSH: TWO IN ONE TOOTHBRUSH, TOOTHPASTE COMBINATION UNIT

Goal: Create a toothbrush with an attached reservoir

Purpose: Provide a solution for the elderly and disabled who struggle with dispensing toothpaste onto their toothbrush

Designed for a class project in Introduction to Mechanical Design

As the lead designer of the team, I was responsible for the following:• Hand drawings• CAD models in Solidworks• Creation of visual pretotypes• Cooperate with my team to create

the best possible design

Switch mechanism to prevent backwash from entering reservoir

Open

Closed

Easily removed cap for simple refilling

Rube Goldberg Machine Segment

Goal: Create a system of simple machines to span a given space

Purpose: To advance the class Rube Goldberg machine

Designed for a class project in Introduction to Mechanical Design

As lead designer and builder of my team’s segment, I was responsible for the following:• Creating the initial design of six

simple machines and submitting for approval

• Modifying design to accommodate input and output requirements of adjacent segments

• Communicate with other teams to ensure success between our segments

• Acquiring all building materials• Constructing the machine

Textbook is hit by previous team and falls at 1, releasing 2 upwards

1 2

2 rising allows 3 to drop, removing a block holding back 4 from going

across the bridge

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4 hits 5, sending it down the ramps

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Full shot of the ramps 5 travels down

5 falls onto 6, which starts the next team’s segment

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