http://hdl.handle.net/1721.1/7684 Thu, 20 Jun 2013 03:18:53 GMT 2013-06-20T03:18:53Z http://hdl.handle.net/1721.1/79316 Manufacturing of lab-on-a-chip devices : characterizing seals for on-board reagent delivery Inamda, Tejas Satish The reagent delivery mechanism in a point-of-care, HIV diagnostic, microfluidic device is studied. Reagents held in an aluminum pack are released on the opening of a fluidic seal. Fluidic seals, controlling the flow of reagents, are characterized to reduce anomalies in the desired flow pattern. The nature of the current seal was investigated. Four seal patterns - line hemisphere, line flat, chevron hemisphere and chevron flat were created and tested for reagent delivery using a flow sensor and a force gauge. Preliminary experiments suggested that one of the patterns - "line-flat" - resulted in fewer flow anomalies. A parameter scoping exercise involving sealing process parameters (temperature, time, gap and distance) was performed for the line flat seal. The findings of this research can be divided into three categories - 1) bonding phenomenon in current seals, 2) influence of seal pattern on flow and rupture mechanics and 3) process parameters which result in the least flow anomalies. The current seal is found to be a bond between the exposed aluminum on the lid film and the heat seal coating on the dome film. The two chevron patterns result in large amounts of flow anomalies, the line hemisphere pattern also resulted in some instances of flow anomalies. The line-flat pattern creates a seal with the least flow anomalies. A specific set of temperature, time, gap and distance which minimizes flow anomalies was found. The flow performance of the reservoir improved and delamination decreased as the distance of the seal from the reservoir was reduced. The thesis also develops a model to better understand the deformation of the reagent carrying dome and flow dynamics prior to and following the opening of the seal. The dome deformation model provides a framework for relating volume, delamination and flow rate to the geometry and material properties of the reservoir pack. Thesis (M. Eng. in Manufacturing)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 93-94). Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/1721.1/79316 2013-01-01T00:00:00Z http://hdl.handle.net/1721.1/79315 Manufacturability of lab on chip devices : reagent-filled reservoirs bonding process and its effect on reagents flow pattern Saber, Aabed (Aabed Saud) In its lab-on-a-chip product, Daktari Diagnostics utilizes "reagent-filled reservoirs" as a means of storing and delivering the liquid reagent. During the clinical trials of the product, undesired reagent flow patterns (namely, flow anomaly 1 & flow anomaly 2) were noticed. This work focused on optimizing the bonding process of the reagent-filled reservoirs to the backbone. Also, the relationship between the bonding process parameters and the reagent flow pattern was studied in depth. To achieve the objective of this thesis, an experiment was designed in which independent variables were the heat sealing parameters (x, y, z) and accelerated aging and the dependent variables were bond strength and the reagent flow pattern. Experiments showed that optimal Heat Sealing parameters are: parameter x = 4.5, parameter y = 110 and parameter z = 1.5. At the optimal settings of bonding process, the highest bond strength was attained and the reagent flow improved considerably but flow anomalies were not completely resolved. Also, results showed that accelerated aging affected the bond strength negatively. Accelerated aging also affected the flow pattern negatively, but this effect was not statistically significant. Thesis (M. Eng. in Manufacturing)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 71-73). Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/1721.1/79315 2013-01-01T00:00:00Z http://hdl.handle.net/1721.1/79279 Real time active sonar simulation in a deep ocean environment Danesh, Sheida Anya Accurate Simulations are important in all fields of science and engineering where experiments and real data are time consuming to obtain and are not easily accessible and/or free of cost. Particularly when operating in environments such as the deep ocean where it could take 2-3 hours for an autonomous underwater vehicle (AUV) to get to a specific depth and where power is very limited. A new module called uSimActiveSonar has been developed in order to simulate an active sonar system with hydrophone data acquisition. This has been done through the use of middleware Mission Oriented Operating Suite (MOOS), ray tracing code BELLHOP as well as using the method outlined by the Naval Research Laboratory to simulate the effects of surface reverberation. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 79-80). Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/1721.1/79279 2013-01-01T00:00:00Z http://hdl.handle.net/1721.1/79278 Bio-inspired pressure sensing for active yaw control of underwater vehicles Gao, Amy (Amy Ruiming) A towed underwater vehicle equipped with a bio-inspired artificial lateral line (ALL) was constructed and tested with the goal of active detection and correction of the vehicle's yaw angle. Preliminary experiments demonstrate that a low number of sensors are sufficient to enable the discrimination between different orientations, and that a basic proportional controller is capable of keeping the vehicle aligned with the direction of flow. We propose that a model based controller could be developed to improve system response. Toward this, we derive a vehicle model based on a first-order 3D Rankine Source Panel Method, which is shown to be competent in estimating the pressure field in the region of interest during motion at constant angles, and during execution of dynamic maneuvers. To solve the inverse problem of estimating the vehicle orientation given specific pressure measurements, an Unscented Kalman Filter is developed around the model. It is shown to provide a close estimation of the vehicle state using experimentally collected pressure measurements. This demonstrates that an artificial lateral line is a promising technology for dynamically mediating the angle of a body relative to the oncoming flow. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 89-92). Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/1721.1/79278 2013-01-01T00:00:00Z