Designing multifunctional pigments for an improved energy efficiency in buildings

Materials science offers solutions that when are combined can offer important energy savings in the building sector. In this study, high reflectance coating and thermal storage capacity are combined with the aim of improving energy efficiency in buildings. For this issue a multifunctional pigment having a phase change material adsorbed on its surface and a high total solar reflectance has been manufactured. The total solar reflectance of the pigment will make the paint to reflect the sunlight radiation in the infrared part of the spectrum reducing the amount of absorbed radiation. This high reflection provides a surface level effect as is a passive stimulus-responsive solution that acts with sunlight radiation. On the other hand, the thermal storage capability provides a bulk level effect as is passive stimulus-responsive solution acting by temperature changes, making it possible to use constructive materials as a thermal energy storage media. The preparation process is described and the pigment is characterized conveniently. The thermal performance of corresponding pigmented coatings was evaluated by an experiment simulation in which different boxes were covered with the coating containing the multifunctional pigment and traditional pigmented coating on their tops. The indoor air temperature and the interior temperature of the substrate were measured obtaining differences of 4–5°C.European Union Seventh Framework Programme, FP7-NMP-2010-Small-5 (under grant agreement no 280393) Dpto. Educación, Política Lingüística y Cultura of the Basque Goverment, IT-630-13 Ministerio de Ciencia e Innovación, MAT2013-42092-R Engineering and Physical Sciences Research Council, EP/I00393

Tribology: The Tool to Design Materials for Energy-Efficient and Durable Products and Process

This chapter describes a summary of the main tribological achievements carried out in TEKNIKER during the last 37 years. It covers the description of commercial and newly developed tribological test benches and case studies for a wide variety of applications. The examples refer to different tribological characterization tools for material selection (e.g., composition, surface treatments, lubricants). It makes emphasis in the failure mechanisms (pitting, scuffing, abrasion, adhesion, thermal fatigue, tribocorrosion, etc.) and friction simulation of a wide range of materials (seals, textiles, steels, cast iron, light alloys, ceramic, composites), tribological systems (mechanical components, biomaterials, tribolubrication), and environments (vacuum, ultrahigh vacuum, low or high temperature, and corrosive). A huge range of new testing equipment and protocols have been developed to simulate the mentioned failure mechanisms and working environments. This knowledge will make possible, in the future, to simulate at laboratory a still wider list of tribological systems and develop new standards. Tribology will help to implement materials solutions into energy and resource efficient products and process, to reduce carbon footprint

Effects of Graphene Oxide and Chemically-Reduced Graphene Oxide on the Dynamic Mechanical Properties of Epoxy Amine Composites

Composites based on epoxy/graphene oxide (GO) and epoxy/reduced graphene oxide (rGO) were investigated for thermal-mechanical performance focusing on the effects of the chemical groups present on nanoadditive-enhanced surfaces. GO and rGO obtained in the present study have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD) demonstrating that materials with different oxidation degrees have been obtained. Thereafter, GO/epoxy and rGO/epoxy nanocomposites were successfully prepared and thoroughly characterized by dynamic mechanical thermal analysis (DMTA) and transmission electron microscopy (TEM). A significant increase in the glass transition temperature was found in comparison with the neat epoxy. The presence of functional groups on the graphene surface leads to chemical interactions between these functional groups on GO and rGO surfaces with the epoxy, contributing to the possible formation of covalent bonds between GO and rGO with the matrix. The presence of oxidation groups on GO also contributes to an improved exfoliation, intercalation, and distribution of the GO sheets in the composites with respect to the rGO based composites.Authors would like to acknowledge the Basque Government funding within the ELKARTEK 2015-2016 (KK-2015/00094) and 2016-2017 (KK-2016/00097) Programme, "ACTIMAT", ETORGAI 2014, Graphnology (ER-2014/00014) and Ayudas para apoyar las actividades de los grupos de investigacion del sistema universitario vasco (IT718-13)

Laser surface tempering of hardened chromium-molybdenum alloyed steel

[Abstract]: The effect of a laser tempering process, subsequent to a laser hardening treatment, on the microstructure, microhardness, structural composition of phases and residual stresses of a 42CrMo4 steel has been studied. The tempering process has been carried out using a 10 kW diode laser and a galvanometer scanner head. Results show that the subsequent tempering process, after the laser hardening treatment, can be a complementary and effective method to adjust, through the selection of the appropriate process parameters, the desired degree of hardness and tensional state of the processed area, attending to the specific requirements demanded in a component

Novel Antibacterial and Toughened Carbon-Fibre/Epoxy Composites by the Incorporation of TiO2 Nanoparticles Modified Electrospun Nanofibre Veils

The inclusion of electrospun nanofiber veils was revealed as an effective method for enhancing the mechanical properties of fiber-reinforced epoxy resin composites. These veils will eventually allow the incorporation of nanomaterials not only for mechanical reinforcement but also in multifunctional applications. Therefore, this paper investigates the effect of electrospun nanofibrous veils made of polyamide 6 modified with TiO2 nanoparticles on the mechanical properties of a carbon-fiber/epoxy composite. The nanofibers were included in the carbon-fiber/epoxy composite as a single structure. The effect of positioning these veils in different composite positions was investigated. Compared to the reference, the use of unmodified and TiO2 modified veils increased the flexural stress at failure and the fracture toughness of composites. When TiO2 modified veils were incorporated, new antibacterial properties were achieved due to the photocatalytic properties of the veils, widening the application area of these composites.This research is funded by the ELKARTEK Programme, “ACTIMAT”, grupos de investigación del sistema universitario vasco (IT718-13), the Spanish government through the project TEC2015-63838-C3-1-R-OPTONANOSENS and from the Basque government through the project KK-2017/00089-µ4F

Understanding informal jewellery apprenticeship in Ghana: Nature, processes and challanges

Context: The processes of acquiring education in jewellery in Ghana has been dominated by the informal apprenticeship system and it forms the backbone of the workforce of the jewellery industry in Ghana. However, the patronage of informal jewellery apprenticeship in Ghana in recent times has been on decline even though it has the potential of training human resources to transform Ghana’s precious mineral resources sector.This is based on the belief that jewellery trade and its training are shrouded in secrecy, in other words, the jewellery trade is considered to be a sacred profession where information on its operating systems are not allowed to be shared easily. It is believed to be associated with cult and magic, hence the reluctant to admit people who are from outside the family of particular jewellery enterprise. This study is sought to bring to fore the understanding nature, processes and challenges of the informal jewellery apprenticeship in Ghana. Approach: The study adopted the descriptive and phenomenology research designs (qualitative research methods). Jewellers who own a jewellery business and who are training other people through apprenticeships as well as people who are trained are observed and interviewed. A sample size was selected through purposive and convenience sampling techniques from four jewellery enterprises in Accra, Ghana. A thematic analysis plan was adopted to generate fndings of the study. Findings: The results show that for a person to train as a jeweller, s/he has to enrol by going through induction, futhremore fees (money and perishable items) are to be paid. The training content is driven by orders received by the master jeweller, thereby making it unstructured and lacking criteria for assessing the performance and progress of apprentice jewellers. Teaching and learning methods are usually on-the-job training that rely on demonstrations and observation. Conclusion: Informal jewellery apprenticeship in Ghana uses a fexible, cost-efective approach for transferring jewellery making skills from masters to apprentice jewellers, and it has substantial potential for improving skills training in the country. Sometimes the reluctant of some jeweller to train others is to keep the trade to family members only

Influence of basin fill architecture on fluid flow and ore genesis in the Mount Isa Basin, Northern Australia

This work has been focused on the one-step fabrication by electrospinning of polyamide 6 (PA6) nanofibre membranes modified with titanium dioxide nanoparticles (TiO2), where these TiO2 nanoparticles aggregates could induce a photocatalytic activity. The main potential application of these membranes could be the purification of contaminated water. Thus, it is important to analyse the contaminant degradation capability since in these membranes this is based on their photocatalytic activity. In this work, the effect of the photocatalysis has been studied both on the degradation of an organic model contaminant and on the removal of Escherichia coli and other coliform bacteria. As a result, it was observed that these membranes present excellent photocatalytic activity when they are irradiated under UV light, allowing a 70% reduction of an organic model pollutant after 240 min. In addition, these membranes successfully removed Escherichia coli and other coliform bacteria in artificially inoculated water after 24 h of contact with them. Moreover, the stand-alone structure of the membranes allowed for the reusing of the immobilized catalyst. The experimental evidence indicated that developed nanofibre membranes are a fast and efficient solution for polluted water decontamination based on photocatalysis. Their use could contribute to guarantee a fresh water level and quality, mitigating the water scarcity problem worldwide