Roberta Garcia

The first European settlements in the new world faced technical issues with the help of the XVI century scientific advances. Besides briefly exposing the scientific and technological situation, this paper explores, with the help of reverse engineering, two singular mechanical wits representative of the technological advances introduced in America to overcome different problems. Firstly, a pump, based on an alternative movement system through crankshafts and pistons used against the continuous flooding suffered in the Ciudad de México valley. Although flooding remained a problem (it was solved in the XX century), hydraulic pumps were essential for continuous soil drainage. Secondly, a port crane for handling cannons, military devices, and construction materials during the Lima fortification in the XVII century. For both cases, reverse engineering, through engineering methods, Computer-Aided Design CAD programs, and additive manufacturing, provides virtual and/or tangible mockups that help to analyze and improve our knowledge about the dimensions, materials, and functions of used (and currently lost) mechanical systems during the American colonization.

Abstract“The Book of Secrets in the Results of Ideas”, usually called “The Book of Secrets” is a codex containing drawings and descriptions of thirty-one artifacts attributed to the engineer Alī Ibn Khalaf al-Murādī, who lived in Andalusia in southern Spain at the beginning of the 11th century. This manuscript is one of the first written testimonies that describe medieval mechanisms with complex precision. The aim of this work is to reconstruct and study from a historical and technological point of view two of the ancient artifacts contained in the “Book of Secrets”, the “Fortress Demolisher” and the “Magic Well”. The “Fortress Demolisher” is a war machine designed to demolish the upper part of the walls or towers and consists of a battering ram mounted on a platform that can be raised several meters above the ground using a scissor mechanism. The “Magic Well” is a mechanism with several pulleys whose purpose is to raise water several meters from the bottom of a well by collecting a small portion of rope. To reconstruct the two artifacts, a digital model and a detailed study of the geometry and operation of the mechanisms, were first carried out. 3D printing, using the Fused Deposition Modelling technology, made the physical reproduction. The digitization and physical reproduction by 3D printing of the mechanisms represent an update of the traditional ways of transmitting knowledge. The use of these new technologies makes the knowledge more accessible, understandable and attractive.

© 2015 American Association of Public Health Dentistry. Objectives: To summarize diagnostic criteria and examiner training and calibration of the National Institute of Dental and Craniofacial Research-funded Early Childhood Caries Collaborating Centers and report examiner calibration results from 2010 to 2014. The EC4 at Boston University, University of Colorado, and University of California San Francisco are performing randomized controlled early childhood caries prevention trials with caries as the main outcome measure. Methods: The EC4 with University of Iowa consultants developed standardized tooth and tooth surface status examination criteria for use in field conditions, examiner training materials, and examiner calibration and re-calibration methodologies. Calibration and re-calibration were performed with 1- to 5-year-old children in the San Francisco Mission District in which assessments from each examiner to be calibrated were compared with those from a single gold standard examiner from 2010 to 2014. Cohen's kappa statistic was used to determine inter-examiner agreement. Results: A total of seven examiners were successfully calibrated during that period, examining a total of 231 children. Overall unweighted Cohen's kappas for 10 surface conditions exceeded the criterion of 0.70. However, separate agreement for assessment of noncavitated lesions, as in other studies, was lower. Conclusions: An experienced multidisciplinary and multi-institutional team was able to develop criteria and training materials to anticipate situations and field conditions the main trials would encounter. Examiners were successfully trained and calibrated.