A simple, versatile robotic arm for classroom and student laboratory use

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaf 21).Robotic arms are indispensable tools in both industry and education. The robotic arm currently used in the MIT class 2.12, Introduction to Robotics, is in need of revision. The arm is heavy, imprecise, bulky, and difficult to customize. The new design presented in this thesis resolves these issues while making the arm more user-friendly and inexpensive enough for classroom use. It uses Hitec HS-805BB hobby servo motors to directly drive each joint. Controlling these motors is effortless with the many commercially available servo motor drivers. Modular construction allows students to change the shape and size of the arm's workspace easily; creating and installing custom linkages is a simple task. Linkages and motor output shafts mount to a common connection shaft with one-sided cut hubs. The radial loads in these shafts are supported by maintenance-free Super Oilite bronze bearings. This robotic arm is better suited for a classroom environment than the current one. It weighs 2.7 pounds; the old one weight 21.2 pounds. Though its workspace and recommended linkage length are about 7% smaller than those of the old design are, it is 87% more precise.(cont.) It is 60% cheaper with a materials cost of $120 for a two degree of freedom arm. The new motors have 343 oz-in of torque, which is sufficient to handle a 12 oz payload 17 inches from the joint axis or a 16 oz payload at 14 inches. Students will spend less time connecting wires and calibrating sensors. This arm should be a welcome addition to the introductory robotics classroom.by David Lafferty.S.B

Infrared spectra of van de Waals complexes of importance in planetary atmospheres

It has been suggested that (CO2)2 and Ar-CO2 are important constituents of the planetary atmospheres of Venus and Mars. Recent results on the laboratory spectroscopy of CO2 containing van der Waals complexes which may be of use in the modeling of the spectra of planetary atmospheres are presented. Sub-Doppler infrared spectra were obtained for (CO2)2, (CO2)3, and rare-gas-CO2 complexes in the vicinity of the CO2 Fermi diad at 2.7 micrometers using a color-center-laser optothermal spectrometer. From the spectroscopic constants the geometries of the complexes have been determined and van der Waals vibrational frequencies have been estimated. The equilibrium configurations are C2h, C3h, and C2v, for (CO2)2, (CO2)3, and the rare-gas-CO2 complexes, respectively. Most of the homogeneous linewidths for the revibrational transitions range from 0.5 to 22 MHz, indicating that predissociation is as much as four orders of magnitude faster than radiative processes for vibrational relaxation in these complexes

Measuring the Effects of Pre-workout Supplementation on Resting Metabolic Rate

Please view abstract in the attached PDF file

A Census Atlas of Irish Agriculture

End of Project ReportComputerised mapping systems were developed to analyse agricultural census statistics and data from agricultural policy administration sources. The objective was to identify local geographical variations in the structure and trends in the agricultural economy by mapping the available information, principally at the level of the District Electoral Division (DED) and the Rural District (RD). There were 3,113 DEDs and 156 RDs in the analysis. The main database was the 1991 Census of Agriculture, the latest available. Some statistics are updated annually and where possible these were used in tabular form to trace the 1991- 1997 trends for Regional Authority areas. Conclusions: There are distinctive farming regions in the country whose boundaries span unevenly across county limits. These are undergoing different processes of change depending on their resource base, their responses to economic imperatives, and the policy environment. • Commercial farming has become increasingly associated with areas south and east of a line from Limerick to Dundalk. • It is likely that policies and trends post 2000 will further increase the differences in resource use between commercial farming and other areas

The effects of parasitism and body length on positioning within wild fish shoals

The influence of body length and parasitism on the positioning behaviour of individuals in wild fish shoals was investigated by a novel means of capturing entire shoals of the banded killifish (Fundulus diaphanus, Lesueur) using a grid-net that maintained the two-dimensional positions of individuals within shoals. Fish in the front section of a shoal were larger than those in the rear. Individuals parasitized by the digenean trematode (Crassiphiala bulboglossa, Haitsma) showed a tendency to occupy the front of shoals. Parasitized fish were also found more in peripheral positions than central ones in a significant number of shoals. Shoal geometry was affected by the overall parasite prevalence of shoal members; shoals with high parasite prevalence displayed increasingly phallanx-like shoal formations, whereas shoals with low prevalence were more elliptical. There was no relationship between body length and parasite abundance or prevalence in the fish population which suggests body length and parasite status are independent predictors of positioning behaviour. Solitary individuals found outside shoals were both more likely to be parasitized and had higher parasite abundance than individuals engaged in shoaling. Differences in the shoaling behaviour of parasitized and unparasitized fish are discussed in the context of the adaptive manipulation hypothesis

Understanding uncertainty in temperature effects on vector-borne disease: A Bayesian approach

Extrinsic environmental factors influence the distribution and population dynamics of many organisms, including insects that are of concern for human health and agriculture. This is particularly true for vector-borne infectious diseases, like malaria, which is a major source of morbidity and mortality in humans. Understanding the mechanistic links between environment and population processes for these diseases is key to predicting the consequences of climate change on transmission and for developing effective interventions. An important measure of the intensity of disease transmission is the reproductive number $R_0$. However, understanding the mechanisms linking $R_0$ and temperature, an environmental factor driving disease risk, can be challenging because the data available for parameterization are often poor. To address this we show how a Bayesian approach can help identify critical uncertainties in components of $R_0$ and how this uncertainty is propagated into the estimate of $R_0$. Most notably, we find that different parameters dominate the uncertainty at different temperature regimes: bite rate from 15-25$^\circ$ C; fecundity across all temperatures, but especially $\sim$25-32$^\circ$ C; mortality from 20-30$^\circ$ C; parasite development rate at $\sim$15-16$^\circ$C and again at $\sim$33-35$^\circ$C. Focusing empirical studies on these parameters and corresponding temperature ranges would be the most efficient way to improve estimates of $R_0$. While we focus on malaria, our methods apply to improving process-based models more generally, including epidemiological, physiological niche, and species distribution models.Comment: 27 pages, including 1 table and 3 figure

Magnetostrictive materials for aerospace applications

Structural health monitoring of composite structures to detect barely visible damage is vitally important for the aerospace industry. This research has investigated amorphous magnetostrictive wires (Fe77.5Si7.5B15 and Co72.5Si12.5B15), as a possible solution to monitoring aerospace composites. The different amorphous wires were either embedded into the composite or epoxied on to the surface. How the wires effected the structure of the composite along with ultimate tensile strength was studied. Inductance measurements were used to study the strain within the composite, which provided a non-intrusive method of monitoring the composite

Mapping Physiological Suitability Limits for Malaria in Africa Under Climate Change

We mapped current and future temperature suitability for malaria transmission in Africa using a published model that incorporates nonlinear physiological responses to temperature of the mosquito vector Anopheles gambiae and the malaria parasite Plasmodium falciparum. We found that a larger area of Africa currently experiences the ideal temperature for transmission than previously supposed. Under future climate projections, we predicted a modest increase in the overall area suitable for malaria transmission, but a net decrease in the most suitable area. Combined with human population density projections, our maps suggest that areas with temperatures suitable for year-round, highest-risk transmission will shift from coastal West Africa to the Albertine Rift between the Democratic Republic of Congo and Uganda, whereas areas with seasonal transmission suitability will shift toward sub-Saharan coastal areas. Mapping temperature suitability places important bounds on malaria transmissibility and, along with local level demographic, socioeconomic, and ecological factors, can indicate where resources may be best spent on malaria control

Fertilidad, desarrollo embrionaria y prolificidad de conejas nulíparas alimentadas con piensos enriquecidos en ácidos grasos poliinsaturados n-3.

Un total de 105 conejas nulíparas se alimentaron ad libitum un mes antes y durante su primera gestación con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=53) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etéreo y 38% de ácidos grasos poli-insaturados (AG n-3) para la dieta experimental (grupo P; n=52). A los 4,5 meses de edad se determinó la fertilidad después de ser inseminadas artificialmente y tratadas con 20 μg de Gonadorelina (Inducel-GnRH, Ovejero) para inducirles la ovulación. Al parto se determinó la duración de la gestación, el número y peso de los gazapos nacidos vivos y muertos. Se escogieron 16 conejas al azar, 8 de cada grupo, y se realizaron ecografías a los 8, 15 y 22 días de gestación en las que se determinó las dimensiones del embrión y de los anejos fetales. La suplementación con AG n-3 no afectó a los resultados productivos determinados ya que se trata de parámetros que en nulíparas son difíciles de mejorar y suelen ser altos. Tampoco se observaron diferencias en las determinaciones ecográficas pero se han podido definir medidas fisiológicas de los fetos y anejos placentarios de gran utilidad para futuros estudios en esta especie