Feature Improvement and Cost Reduction of Baitcasting Fishing Reels for Emerging Markets

Baitcasting fishing reels are a challenging product to sell to new users in emerging markets. Their complex and less-than-intuitive design make them poor candidates for a novice fisherman selecting his or her first fishing reel. Based upon manufacturer constraints and design requirements, our team lowered the price point and improved the usability of the Okuma Cerros baitcasting fishing reel to make it more appealing to a wider range of consumers, especially in emerging markets. This project resulted in a three-phase redesign: reducing cost via alternative materials and replacing bearings with bushings; prototyping a simplified cast control system; and proposing an improved user interface

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The design of a power system using treated aluminum fuel

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.Includes bibliographical references (pages 85-87).Aluminum is the most abundant metal in the Earth's crust and a highly sought after fuel source due to its extreme energy density. It has the ability to produce large quantities of hydrogen and heat when reacted with water making it an attractive fuel for underwater vehicles and ocean sensor platforms. The biggest challenge in using aluminum as a fuel has been overcoming the rapidly-forming oxide layer that gives aluminum its excellent corrosion resistance. Recently, a safe, controllable, and inexpensive treatment process was developed which bypasses this layer and allows aluminum to efficiently react with water. The fuel made using this process generates an average hydrogen yield of 94 percent. This fuel has been successfully tested in a power system, in which a fuel cell generated 30 watts for 90 minutes using only hydrogen. Firstly, an introduction and background is given on the benefits and challenges of using hydrogen as a fuel. The basic chemistry and background behind using aluminum as a fuel provides the motivation behind this thesis. Secondly, the materials science of using aluminum fuels is examined as well as prior aluminum fuels which have been attempted. The treatment process is then analyzed using the physics previously discussed as well as the overall efficiency and practicality of the treated aluminum fuel. Thirdly, a working power system design is then presented which runs entirely off hydrogen gas generated by specially treated aluminum fuel. This system was run for 90 minutes at 30 watts, showing that aluminum can be used as a safe and environmentally friendly fuel source.by Jonathan Slocum.S.M

Design and modeling of a force sensitive toothbrush by using a buckling truss structure

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.Includes bibliographical references (page 39).Excessive force applied to teeth with a toothbrush during brushing may cause tooth erosion and gum recession. There have been many attempts by others to mitigate this effect with a force-sensitive toothbrush that can alert a user when excessive force is applied. However, many of the prior art solutions to this problem do not have a tactile response to alert the user when excessive force is applied. Further many prior art solutions are often bulky, have multiple components, and/or are not aesthetically pleasing or ergonomic. Some prior art buckling structures also often had thin hinge sections which are difficult to injection mold and act as failure points and the resulting broken structure can be dangerous. Prior art buckling toothbrush structures further had the problem of once they buckled, the structure was so substantially weakened, that continued application of force could cause the structure to plastically fail. A force-sensitive toothbrush incorporates a bistable truss into the neck of the toothbrush. The mechanism can alert a user to excessive brushing force by changing shape in response to brushing forces exceeding a predetermined threshold. The mechanism can also automatically return to its original state when the brushing forces are lowered back down below the predetermined level. The mechanism may include a force-sensitive region having an upper beam and a lower beam joined together to form a triangular truss, both grounded to the handle. This mechanism can advantageously be molded into an integral toothbrush body using an injection molding operation.by Jonathan Slocum.S.B

A buckling flexure-based force-limiting mechanism

A force-limiting buckling flexure has been created which can be used in a wide array of applications where excessive force from an implement can cause harm or damage. The buckling flexure is monolithic, contains no electronics, and can be manufactured using a single shot in an injection molding machine, making it extremely cost effective. In this paper, the design of this flexure is applied to a force-limiting toothbrush as an example of how this buckling flexure may be applied in a real-world technology. An overview of the buckling flexure is presented, and a structural model is shown to predict when the flexure will elastically buckle. This model is compared to data collected from flexures fabricated with varying buckling beam thickness. The data show that the force to buckle the flexure when applied at the tip can be predicted to within 20.84%. Furthermore, a preliminary model is presented which enables design of the buckling beam’s displacement, such that the total breakaway deformation can be maximized, making sensing the sudden deformation easier. As part of the application of the buckling flexure, an ergonomic, injection moldable toothbrush was created with the flexure built into the neck of the brush. When the user applies too much force while brushing, the flexure gives way and alerts the user when they have applied too much force and when the user lets off the force, the brush snaps back to its original shape. This design methodology is generalized and can be utilized in other force limited applications where an injection moldable, pre-set force, purely mechanical breakaway device is desired.978-0-7918-5180-

Development of a long-acting direct-acting antiviral system for hepatitis C virus treatment in swine

Chronic hepatitis C virus (HCV) infection is a leading cause of cirrhosis worldwide and kills more Americans than 59 other infections, including HIV and tuberculosis, combined. While direct-acting antiviral (DAA) treatments are effective, limited uptake of therapy, particularly in high-risk groups, remains a substantial barrier to eliminating HCV. We developed a long-acting DAA system (LA-DAAS) capable of prolonged dosing and explored its cost-effectiveness. We designed a retrievable coil-shaped LA-DAAS compatible with nasogastric tube administration and the capacity to encapsulate and release gram levels of drugs while resident in the stomach. We formulated DAAs in drug-polymer pills and studied the release kinetics for 1 mo in vitro and in vivo in a swine model. The LA-DAAS was equipped with ethanol and temperature sensors linked via Bluetooth to a phone application to provide patient engagement. We then performed a cost-effectiveness analysis comparing LA-DAAS to DAA alone in various patient groups, including people who inject drugs. Tunable release kinetics of DAAs was enabled for 1 mo with drug-polymer pills in vitro, and the LA-DAAS safely and successfully provided at least month-long release of sofosbuvir in vivo. Temperature and alcohol sensors could interface with external sources for at least 1 mo. The LA-DAAS was cost-effective compared to DAA therapy alone in all groups considered (base case incremental cost-effectiveness ratio $39,800). We believe that the LA-DAA system can provide a cost-effective and patient-centric method for HCV treatment, including in high-risk populations who are currently undertreated.NIH (Grants EB000244 and 5T32DK007191-45

Structure, function and pharmacology of human itch GPCRs.

The MRGPRX family of receptors (MRGPRX1-4) is a family of mas-related G-protein-coupled receptors that have evolved relatively recently1. Of these, MRGPRX2 and MRGPRX4 are key physiological and pathological mediators of itch and related mast cell-mediated hypersensitivity reactions2-5. MRGPRX2 couples to both Gi and Gq in mast cells6. Here we describe agonist-stabilized structures of MRGPRX2 coupled to Gi1 and Gq in ternary complexes with the endogenous peptide cortistatin-14 and with a synthetic agonist probe, respectively, and the development of potent antagonist probes for MRGPRX2. We also describe a specific MRGPRX4 agonist and the structure of this agonist in a complex with MRGPRX4 and Gq. Together, these findings should accelerate the structure-guided discovery of therapeutic agents for pain, itch and mast cell-mediated hypersensitivity