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This paper aims to propose using polylactic acid (PLA) as an alternative to nanocomposites in additive manufacturing processes in fusion deposition modelling (FDM) systems and describe its thermal and rheological conditions with multi-wall carbon nanotube (PLA/MWCNT) and halloysite nanotube (PLA/HNT) composites for possible applications in additive manufacturing processes.

PLA/MWCNTs and PLA/HNTs were obtained through fusion in a co-rotating twin-screw extruder. PLA was mixed with different percentages of MWCNTs and HNTs at concentrations of 0.5 Wt.%, 0.75 Wt.% and 1 Wt.%. Differential scanning calorimetry (DSC) and capillary rheometry were used to characterise these products, together with an analysis of the melt flow index (MFI).

The DSC data revealed that the nanocomposites had a glass transition temperature T_g = 65 ± 2°C and a melting temperature T_m = 169 ± 1°C. The crystallisation temperature of PLA/MWCNTs and PLA/HNTs was between 107 ± 2°C and 129°C, respectively. The viscosity data of PLA/MWCNTs and PLA/HNTs obtained by capillary rheometry indicated that the viscosity of the materials is the same as that of neat PLA. These results were confirmed by the higher fluidity index in the MFI analysis.

This paper presents an alternative for the applications of nanocomposites in additive manufacturing processes in FDM systems.

This paper aims to describe the influence of maleinized linseed oil (MLO), when used as a lubricant, on the thermal and rheological properties of PLA/MWCNTs (polylactic acid/multi-walled carbon nanotubes) and PLA/HNT (halloysite nanotubes) nanocomposites, as a reference for application in 3D printing processes.

Nanocomposites were obtained by melting in a twin-screw extruder, mixing PLA with MWCNTs and HNTs in different percentages of 0.5, 0.75 and 1 Wt.% for subsequent mixing by the same process with 5 phr MLO, for application in additive manufacturing, as analyzed by means of differential scanning calorimetry (DSC), capillary rheometry, melt flow rate (MFL) and field emission scanning electron microscopy (FESEM).

The results obtained for thermal characterization by using DSC indicate the non-variation of glass transition temperature Tg = 62 ± 2°C and a melting temperature (Tm) around 170°C. Crystallization temperature dropped by approximately 12°C, which should be kept in mind during the transformation processes. The values obtained by capillary rheometry indicate that the material’s viscosity is reduced by the influence of the MLO plasticizer’s lubricant effect on the PLA’s molecular structure. The melt flow index values confirm a rise of approximately 46% in the flow index and back up the capillary rheometry results. The values obtained were as follows: PLA/0.5 Wt.% MWCNT/MLO 5 phr 54.07, PLA/0.75 Wt.% MWCNT/MLO 5 phr 53.46, PLA/1 Wt.% MWCNT/MLO 5 phr 51.84y PLA/0.5 Wt.% HNT/MLO 5 phr 61.8, PLA/0.75 Wt.% HNT/MLO 5 phr 68.3 and PLA/1 Wt.% HNT/MLO 5 phr 71.2 g/10 min. Apart from the nanocharge distribution, the information obtained from the FESEM shows the existence of a cluster, which could have been avoided by more energetic stirring during the nanocompound manufacturing process.

This paper presents an analysis of the insertion of plasticizer in nanocomposites for the application in additive manufacturing processes in fusion deposition modelling (FDM) system.

This is a novel original research work.

The purpose of this study is to analyse the concept of dark tourism and apply it to the Valley of the Fallen in Spain, a controversial monument that is a symbol of the Spanish Civil War and the subsequent dictatorship.

First, the authors carried out a literature review to get an insight into the concept of “dark tourism”, the types of existing dark tourism and the methods that are applied to the main cases around the world. Then, the authors analysed the case through a content analysis of press articles and interviews.

The authors propose a way to change the current symbolism and connotations of the Valley of the Fallen towards a new symbolism engaging all the stakeholders involved, from a dark tourism point of view.

Applying this new symbolism requires attaining a difficult consensus that Spain has not yet been able to put into practice.

The dark tourism framework is an opportunity to link both economic and educational objectives, co-working on a model of consensus, but there is a gap in the literature on dark tourism in terms of Spain’s history. This strategy could be also applied to other controversial heritage with similar characteristics, according to different positioning classifications.

The substantial resources devoted to warfare in modern times might explain the increasing relevance that military spending has acquired in social sciences. In this regard, the so-called defence economics has extensively studied the main determinants of military spending and its main consequences in terms of economic performance and institutional transformations. However, one of the main problems for comparative analysis on the causes and effects of military spending is the lack of long-term homogeneous and comparable data in international panel datasets. This paper contributes to fill in this gap by providing new military spending data on Spain from 1850 to 2009 based on NATO methodological criterion. It provides total military spending estimates as well as economic and administrative disaggregated figures for most of the period. These data allow reliable international comparisons while also providing new quantitative evidence to better understand the military history of Spain in modern times.

The purpose of this paper is to introduce a country’s mixed history of colonialism and cultural heritage as a background to the management of a mining company’s community engagement. Mining-related social conflicts have intensified in Peru as mining expansion challenges Andean people’s traditional livelihoods. It is generally thought that resolving such conflicts requires a set of long-term strategies and engagement.

The case study has been developed using an inductive methodology through content analysis of newspaper reports, official documents and the academic literature. It follows a complex and evolving situation, blending social and cultural theory and norms with actual events to provide insight into the conflicts’ historical, social and cultural forces.

Mining conflicts are complex business and strategic problems that call for a more thorough analysis of causal variables and a deeper understanding of the underlying cultural and historical forces. Transactional community engagement responses may not always be adequate to maintain a mining project’s social licence.

Based on the information presented, students can use the case as a means to examine and critique community engagement approaches to social conflict resolution through this summary of a real-life example of social conflict in Peru’s mining industry. The case may also be used as the basis for teaching forward planning and contingency management for long-term projects involving stakeholders and potential conflict. The case has been used as a resource for teaching communications, risk evaluation and community engagement strategies as part of a Master’s in the Energy Sector Management programme in Peru.

Este caso propone una introducción a la historia del colonialismo y multiculturalismo en el Perú relacionado con el manejo de las relaciones comunitarias por parte del sector minero. Los conflictos sociales provenientes de la actividad minera se han intensificado en el Perú debido a que esta industria insiste en desafiar el estilo de vida de los pueblos andinos. Se piensa que una solución de estos conflictos requiere un conjunto de estrategias y compromisos a largo plazo.

El estudio de caso se ha desarrollado utilizando una metodología inductiva a través del análisis de contenido de informes periodísticos, documentos oficiales y la literatura académica. Se analiza una situación compleja, mezclando la teoría y las normas sociales y culturales con los acontecimientos actuales para proporcionar una visión de las fuerzas históricas, sociales y culturales que sustentan los acontecimientos que ocurren.

Los conflictos mineros son problemas de negocios complejos y estratégicos que requieren un análisis más profundo de las variables causales y una comprensión más profunda de las fuerzas culturales e históricas subyacentes. Las respuestas transaccionales de participación de la comunidad no siempre son adecuadas para mantener la licencia social de un proyecto minero.

Basados en la información presentada, los estudiantes pueden usar el caso como un medio para examinar y criticar los enfoques de participación comunitaria en la resolución de conflictos sociales a través de un ejemplo real de conflicto social en la industria minera peruana. El caso también puede utilizarse como base para enseñar la planificación anticipada y la gestión de contingencias para proyectos a largo plazo que involucren a las partes interesadas. El caso se ha utilizado como recurso para la enseñanza de comunicaciones, estrategia, evaluación de riesgos y de participación comunitaria como parte de un programa de Maestría en Gestión del Sector Energético en Perú.