Development and implantation of a Thesaurus of Manufacturing Engineering terms

Present work shows the teaching-learning experience developed in the Department of Manufacturing Engineering of the University of Malaga. This experience is based on the need to generate a specific glossary of manufacturing engineering terms to be used as a study guide by the students. Eventually, it was decided to make a Thesaurus that would be aimed at a teaching activity. Also, it would take part in the educational innovation project PIE 13-025 of the University of Malaga, within the biennium 2013/2015. The first step consisted of the design of Thesaurus pattern, taking into account the kind of information that it was necessary include in it. Afterward, this pattern would be place on the Virtual Campus and the student would have to complete the information required. Finally, the results obtained in the different applications of this activity would be analyzed and evaluated.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Nanowires: A route to efficient thermoelectric devices

Miniaturization of electronic devices aims at manufacturing ever smaller products, from mesoscopic to nanoscopic sizes. This trend is challenging because the increased levels of dissipated power demands a better understanding of heat transport in small volumes. A significant amount of the consumed energy is transformed into heat and dissipated to the environment. Thermoelectric materials offer the possibility to harness dissipated energy and make devices less energy-demanding. Heat-to-electricity conversion requires materials with a strongly suppressed thermal conductivity but still high electronic conduction. Nanowires can meet nicely these two requirements because enhanced phonon scattering at the surface and defects reduces the lattice thermal conductivity while electric conductivity is not deteriorated, leading to an overall remarkable thermoelectric efficiency. Therefore, nanowires are regarded as a promising route to achieving valuable thermoelectric materials at the nanoscale. In this paper, we present an overview of key experimental and theoretical results concerning the thermoelectric properties of nanowires. The focus of this review is put on the physical mechanisms by which the efficiency of nanowires can be improved. Phonon scattering at surfaces and interfaces, enhancement of the power factor by quantum effects and topological protection of electron states to prevent the degradation of electrical conductivity in nanowires are thoroughly discussed

Tobacco use in the third trimester of pregnancy and its relationship to birth weight. A prospective study in Spain

Background Few studies have been carried out in Spain examining the use of tobacco amongst expectant mothers and its effect on birth weight. Aims To observe the proportion of expectant mothers who smoke during their pregnancy, and the impact of tobacco consumption on maternal and birth weight. We also aimed to identify the trimester of pregnancy in which tobacco use produced the greatest reduction in birth weight. Methods Prospective observational study in Spain. A random sampling strategy was used to select health centres and participant women. A total of 137 individuals were enrolled in the study. Exposure to tobacco was measured through a self-reported questionnaire. Regressions were performed to obtain a predictive model for birth weight related to smoking. Findings Overall, 35% of study participants were smokers during the pre-gestational period (27% in the first trimester, 21.9% in the second and 21.2% in the third). 38.7% of smoking cessation attempts took place in the third-trimester. Pregnant women who smoked up to the third trimester had a higher risk of giving birth to a baby under 3000 g, compared to non-smokers (OR = 5.94, CI 95%: 1.94–18.16). Each additional unit of tobacco consumed daily in the 3rd trimester led to a 32 g reduction in birth weight. Conclusion An important proportion of pregnant women in Spain smoke during pregnancy. Pregnant women exposed to tobacco have newborns with lower birth weight. Smoking during the 3rd trimester of pregnancy is associated with the greatest risk of lower birth weight

Interplay between the magnetic anisotropy contributions of Cobalt nanowires

We report on the magnetic properties and the crystallographic structure of the cobalt nanowire arrays as a function of their nanoscale dimensions. X-ray diffraction measurements show the appearance of an in-plane HCP-Co phase for nanowires with 50 nm diameter, suggesting a partial reorientation of the magnetocrystalline anisotropy axis along the membrane plane with increasing pore diameter. No significant changes in the magnetic behavior of the nanowire system are observed with decreasing temperature, indicating that the effective magnetoelastic anisotropy does not play a dominant role in the remagnetization processes of individual nanowires. An enhancement of the total magnetic anisotropy is found at room temperature with a decreasing nanowire diameter-to-length ratio (d/L), a result that is quantitatively analyzed on the basis of a simplified shape anisotropy model.Comment: 8 pages, 4 figure

Voltage dip generator for testing wind turbines connected to electrical networks

This paper describes a new voltage dip generator that allows the shape of the time profile of the voltage generated to be configured. The use of this device as a tool to test the fault ride-through capability of wind turbines connected to the electricity grid can provide some remarkable benefits: First, this system offers the possibility of adapting the main features of the time–voltage profile generated (dip depth, dip duration, the ramp slope during the recovery process after clearing fault, etc.) to the specific requirements set forth by the grid operation codes, in accordance with different network electrical systems standards. Second, another remarkable ability of this system is to provide sinusoidal voltage and current wave forms during the overall testing process without the presence of harmonic components. This is made possible by the absence of electronic converters. Finally, the paper includes results and a discussion on the experimental data obtained with the use of a reduced size laboratory prototype that was constructed to validate the operating features of this new device

VIMOS-VLT spectroscopy of the giant Ly-alpha nebulae associated with three z~2.5 radio galaxies

The morphological and spectroscopic properties of the giant (>60 kpc) Ly-alpha nebulae associated with three radio galaxies at z~2.5 (MRC 1558-003, MRC 2025-218 and MRC 0140-257) have been investigated using integral field spectroscopic data obtained with VIMOS on VLT. The morphologies are varied. The nebula of one source has a centrally peaked, rounded appearance. In the other two objects, it consists of two spatial components. The three nebulae are aligned with the radio axis within <30 deg. The total Ly-alpha luminosities are in the range (0.3-3.4) x 1e44 erg s-1. The Ly-alpha spectral profile shows strong variation through the nebulae, with FWHM values in the range ~400-1500 km s-1 and velocity shifts V~120-600 km s-1. We present an infall model which can explain successfully most Ly-alpha morphological and spectroscopic properties of the nebula associated with MRC 1558-003. This adds further support to our previous conclusion that the _quiescent_ giant nebulae associated with this and other high redshift powerful radio galaxies are in infall. A problem for this model is the difficulty to reproduce the large Ly-alpha FWHM values. We have discovered a giant (~85 kpc) Ly-alpha nebula associated with the radio galaxy MRC 0140-257 at z=2.64. It shows strikingly relaxed kinematics (FWHM2) radio galaxies.Comment: 14 pages, 13 figures. Accepted for publication in MNRA

The origin of the Acheulean: the 1.7 million-year-old site of FLK West, Olduvai Gorge (Tanzania)

The appearance of the Acheulean is one of the hallmarks of human evolution. It represents the emergence of a complex behavior, expressed in the recurrent manufacture of large-sized tools, with standardized forms, implying more advance forethought and planning by hominins than those required by the precedent Oldowan technology. The earliest known evidence of this technology dates back to c. 1.7 Ma. and is limited to two sites (Kokiselei [Kenya] and Konso [Ethiopia]), both of which lack fauna. The functionality of these earliest Acheulean assemblages remains unknown. Here we present the discovery of another early Acheulean site also dating to c. 1.7 Ma from Olduvai Gorge. This site provides evidence of the earliest steps in developing the Acheulean technology and is the oldest Acheulean site in which stone tools occur spatially and functionally associated with the exploitation of fauna. Simple and elaborate large-cutting tools (LCT) and handaxes co-exist at FLK West, showing that complex cognition was present from the earliest stages of the Acheulean. Here we provide a detailed technological study and evidence of the use of these tools on the butchery and consumption of fauna, probably by early Homo erectus sensu lato