Design of a desktop milling machine for fabrication in an introductory machine shop class

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references.The purpose of this research is to design, fabricate and test the electromechanical subsystem of a CNC milling machine kit. Unlike all other CNC kits on the market, the purpose of this kit is to teach students the principles of electro mechanics during its construction and to teach the principles of CNC machining during its operation. The design process and final designs of both the software and electronic subsystems are described and evaluated. The CNC kit is assembled using off-the-shelf, easy-to-use electronic elements. The software is programmed using Matlab, a common and easy to program software system purchased for all students by MIT. The outline for a course in which this kit could be taught is given, including sample code and circuit schematics.by Dan Lorenc.S.B

Orbital transfer vehicle oxygen turbopump technology. Volume 1: Design, fabrication, and hydrostatic bearing testing

The design, fabrication, and initial testing of a rocket engine turbopump (TPA) for the delivery of high pressure liquid oxygen using hot oxygen for the turbine drive fluid are described. This TPA is basic to the dual expander engine which uses both oxygen and hydrogen as working fluids. Separate tasks addressed the key issue of materials for this TPA. All materials selections emphasized compatibility with hot oxygen. The OX TPA design uses a two-stage centrifugal pump driven by a single-stage axial turbine on a common shaft. The design includes ports for three shaft displacement/speed sensors, various temperature measurements, and accelerometers

Learning to breathe with Tai Chi online - qualitative data from a randomized controlled feasibility study of patients with cystic fibrosis

Introduction Tai Chi (TC), a gentle exercise, incorporates meditative movement and respiratory control. The high risk of cross infection for people with cystic fibrosis (CF) requires close management in healthcare settings, limiting group activities such as TC. A mixed-methods randomized controlled feasibility study compared teaching TC over the internet with in-person, face to face TC tuition provided to CF patients. This article explores qualitative data from patients and TC instructors on their attitudes, acceptability and engagement with the two modes of TC delivery. Methods Qualitative data from CF patients (>6 years) were collected using Skype interviews/focus groups and written feedback. TC instructors provided weekly written feedback, and took part in interviews/ focus groups at the end of the study. Patient and instructor interviews explored their experiences and engagement with TC online delivery and ability to practice. Results Irrespective of the type of TC delivery, all CF participants interviewed (n = 28) practiced between lessons and most wanted to continue TC. Teenagers were more likely to miss TC appointments. Internet delivery was well received by both patients and TC instructors. Two patients reported difficulties with screen size/camera and one with internet connectivity. Conclusion Both face-to-face and internet delivery of TC lessons were equally well received and perceived as beneficial. In the current COVID-19 pandemic, CF patients self-isolating could find this intervention provides important support, therefore the programme was made available on YouTube in April 2020 and linked to the websites of the CF charities funding the research

Machine learning for next-generation nanotechnology in healthcare

Funding: The authors acknowledge financial support from FCT Portugal in the framework of PhD grant 2020.06638.BD (to D.P.S.), and the European Research Council grant agreement 848325 (J. Conde for the ERC Starting Grant). T.R. is an Investigador Auxiliar supported by FCT Portugal (CEECIND/ 00684/2018).Nanotechnology for healthcare is coming of age, but automating the design of composite materials poses unique challenges. Although machine learning is supporting groundbreaking discoveries in materials science, new initiatives leveraging learned patterns are required to fully realize the promise of nanodelivery systems and accelerate development pipelines.publishersversionpublishe

An update on THORPEX-related research in data assimilation and observing strategies

International audienceThe international programme "THORPEX: a World Weather Research Programme" provides a framework in which to tackle the challenge of improving the forecast skill of high-impact weather through international collaboration between academic institutions, operational forecast centres, and users of forecast products. The objectives of the THORPEX Data Assimilation and Observation Strategy Working Group (DAOS-WG) are two-fold. The primary goal is to assess the impact of observations and various targeting methods to provide guidance for observation campaigns and for the configuration of the Global Observing System. The secondary goal is to setup an optimal framework for data assimilation, including aspects such as targeted observations, satellite data, background error covariances and quality control. The Atlantic THORPEX Regional campaign, ATReC, in 2003, has been very successful technically and has provided valuable datasets to test targeting issues. Various data impact experiments have been performed, showing a small but very slightly positive impact of targeted observations. Projects of the DAOS-WG include working on the AMMA field experiment, in the context of IPY and to prepare the future THORPEX-PARC field campaign in the Pacific by comparing sensitivity of the forecasts to observations between several groups

Biomechanics of predator–prey arms race in lion, zebra, cheetah and impala

The fastest and most manoeuvrable terrestrial animals are found in savannah habitats, where predators chase and capture running prey. Hunt outcome and success rate are critical to survival, so both predator and prey should evolve to be faster and/or more manoeuvrable. Here we compare locomotor characteristics in two pursuit predator–prey pairs, lion–zebra and cheetah–impala, in their natural savannah habitat in Botswana. We show that although cheetahs and impalas were universally more athletic than lions and zebras in terms of speed, acceleration and turning, within each predator–prey pair, the predators had 20% higher muscle fibre power than prey, 37% greater acceleration and 72% greater deceleration capacity than their prey. We simulated hunt dynamics with these data and showed that hunts at lower speeds enable prey to use their maximum manoeuvring capacity and favour prey survival, and that the predator needs to be more athletic than its prey to sustain a viable success rate