Search

The MAJORANA DEMONSTRATOR is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluids from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.

The purpose of this article is to show a software application made for online calibration via Internet from simple measuring instruments from the dimensional area (exterior micrometer and calliper). It also shows the educational results obtained in the teaching experiences where it has been used. The environment created makes it possible to replace real practices with virtual simulations where the student must make the proper metrological decisions and make the necessary calculations to determine the instruments' expanded uncertainty. This software has shown to be a very useful and efficient tool in training the distance learning students in the course titled: 'Calibration Plan for Ensuring Quality in Industrial Laboratories,' offered by Technical University of Madrid. Furthermore, some very notable academic results have been achieved among students from two pilot groups for the Mechanical Engineering degree program. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 387-399, 2013 [ABSTRACT FROM AUTHOR]

The object of this paper is to outline the interactive teaching model developed by tile education innovation group 'New Teaching Methodologies in Mechanical and Manufacturing Engineering Technology' of the Polytechnic University of Madrid. The aim of the model is to teach the subject of Manufacturing Engineering Technology for the Mechanical Technical Engineering degree course. It is based on a new face-to-face methodology that we have called DE-learning (driven electronic learning) in which theoretical teaching and laboratory teaching are combined in a collaborative environment, managed through the developed software that combines: theoretical lessons, solved practical examples, exercises, bibliographical references, Webpage links and self-assessment tests. [Here the term 'collaborative' is used to describe the teaching methodology whereby student-to-student and student-to-teacher relationships take place in the learning process and not exclusively through a one way teacher-to-student relationship. ] The teaching of this new model is 'driven" under the guidance and supervision of a professor, in an educational environment with no formally taught classes. Students themselves can decide on the pace at which the), learn, the resources used, the definition and carrying out of practical exercises and whether the), wish to form collaborations among themselves during study time. The fundamental advantage of this model is its efficiency in optimising learning time, given that." (a) all the necessary resources are accessible to the student through electronic teaching support, (b) the laboratory, practical classes take place in the same environment, as the), are combined and connected to the theoretical concepts without any break in continuity, and (c) students' problems can be resolved in a personal and immediate way by the professor. In addition to this, other advantages have emerged that are equally relevant in the engineering training of the students: the development of better communication skills as well as their skills and abilities, motivation, creativity and increase in confidence and confidence in their decisions. The efficacy of this new teaching model has been confirmed through the academic results attained by the students during the 2006107 academic year, which are presented in this paper. [ABSTRACT FROM AUTHOR]

This article describes the structure and content of educational software, developed with the aim of training engineering students in the calibration of standards and instruments, in the field of dimensional metrology. The virtual character of the environment created makes it possible to substitute practising with real metrological equipment for versatile and interactive simulations that provide advantages such as: the reduction in the cost of acquiring and maintaining standards and instruments; the absence of time and space constraints; the provision of training in any metrology condition, and accessibility for students with movement or sensory limitations, etc. The structure of the programme requires the students to engage in active learning. As such, they have to make metrological decisions that ensure traceability and estimate the uncertainties in accordance with the established calibration procedures. A pilot project was carried out with the aim of analysing the teaching viability of the program. This made it possible to objectively evaluate the level of learning reached by mechanical engineering students at the Polytechnic University of Madrid. [ABSTRACT FROM AUTHOR]

This article presents the results of an LMM-R-2019 interlaboratory comparison. Such comparisons of different families of measuring instruments are one of the activities conducted among the calibration laboratories to maintain their ISO 17025 accreditation. Given that the study of surface roughness is becoming increasingly important in the field of dimensional metrology, the comparison focused on determining the Ra parameter on a pseudorandom metallic roughness standard using two types of measuring instruments: physical contact (stylus instruments) and optical (confocal microscopes). Among the aspects studied was whether the roughness measurements obtained using calibrated confocal microscopes could be compared with those using traditional methods since optical instruments obtain measurements more quickly and responsively than do stylus instruments. The results showed that roughness measurements using confocal microscopes are comparable with those from a traditional stylus instrument.

This work describes a method for the metrological characterization of structured surfaces using a confocal microscope. The proposed method is based on the calculation of texture parameters established in ISO 25178-2:2012. To ensure the traceability of these parameters, a procedure for the calibration of the Z-axis of the confocal microscope is proposed. The calculation of uncertainty associated with each parameter employs the Monte Carlo method, as well as the concept of a virtual instrument. The validity of the algorithms has been verified through the use of synthetic data provided by the National Institute of Standards and Technology (NIST) and physical standards, with minimum differences being obtained between the certified values and calculated or measured values. Finally, using the proposed method, the topography of a structured surface manufactured by laser machining is evaluated, obtaining the most used roughness parameters, as well as their measurement uncertainties and possible correlations. In general, it can be affirmed that it is possible to obtain metrologically reliable results with the proposed method.