Highly pure iron pyrites (FeS2) cubic phased nanocrystals of diameter ∼ 20 nm were synthesized by colloidal method using only amines acting both as a coordinating and surfactant ligands. The details of synthetic condition at temperature 175 °C, 215 °C, 230 °C, 245 °C were compared and elucidated. The best synthetic conditions using an octylamine as a ligand at 230 °C for 2h have been optimized in an inert atmosphere. The XRD measurement shows diffraction peaks of pure cubic iron pyrite crystal structure without any detectable presence of marcasite, pyrrotite, greigyte and other impurity structures. The UV-Vis spectra depict clear absorption onset at 1200 nm in best sample with estimated band gap of ∼1.03 eV. These high pure and nanostructures based iron pyrite processed from solution route may offer excellent manufacturing scalability at very low cost since it can be used as inks for large scale fabrication. The morphological and optical characterizations are carried out by using XRD, UV-Vis, and SEM techniques.

Humanity currently extracts almost 70 billion tons of materials per year. During the last century global materials extraction and use have increased by one order of magnitude. Growth accelerated in the last decade, when materials extraction grew with the global economy at an annual rate of 3.6%. For sustainable development it is of key importance to understand the spatial and temporal dynamics of global material use and the underlying drivers. This paper explores changes in global material use during the last century from a systemic perspective based on the concept of socio-economic metabolism.

In recent years socio-economic (or, more narrowly termed industrial) metabolism became a prominent concept in sustainability science as many global sustainability problems are directly associated with humanities growing demand for raw materials and their transformation into wastes and emissions after processing and use. Material Flow Analysis (MFA) is one of the approaches available to study social metabolism. It provides data and headline indicators for resource use in national economies and is widely used in science and by policy makers.

This paper presents results from a global material flow analysis and explores long term the development of global material extraction and use. It shows that in particular the period after WWII was characterized by a rapid expansion of resource use, driven by both population and economic growth. Within this period a shift from the dominance of renewable biomass towards mineral and fossil materials, which now account for 70% of all used materials, was observed. Overall, material use increased at a slower pace than the global economy, but faster than world population. As a consequence, material intensity (i.e. the amount of materials required per unit of GDP) declined throughout the 20th century, while materials use per capita doubled. The use of materials is by no means equally distributed around the globe. Per capita material use varies by a factor of 20 across countries. At the turn of the millennium, 15% of the global population living in industrialized countries were using half of all mineral and fossil resources; in contrast, the least developed countries, inhabiting 11% of global population, appropriated only 1% of these strategically important materials. In recent years, however, the emerging economies gained significance as drivers for physical growth. So far there is no evidence that growth of global materials use is slowing down. The paper discusses the implications of the results from the material flow analysis for sustainable development.

A SiC-based ceramic foam applied in solar thermal processes was characterized in detail in terms of its textural parameters and its radiative properties. Scanning electron microscopy and x-ray µ-tomography were first performed to investigate the 3D texture of the sample at several length scales. Infrared reflectance microscopy was also applied to probe the local optical responses on the struts constituting the foam. Based on the whole set of experimental data, a numerical tool (C++) was implemented to reconstruct virtual SiC foams. A Monte Carlo Ray Tracing code (iMorphRad, C++) was then used to compute the normal spectral emittance for the real SiC foam and for another reconstructed SiC foam with similar textural features. The two numerically determined emittances were then compared with previous infrared spectroscopy experimental measurements. This numerical procedure enables us to propose a methodology for the design of SiC foams with prescribed radiative properties.

The concept of low carbon, energy saving and sustainable design has been widely accepted all over the world. As a matter of fact, large amount energy is consumed to control the indoor environment to maintain a comfortable ambience for living and working. To increase the energy utilization efficiency, phase change material (PCM), which can store and release heat through phase change, has been recognized as an excellent candidate for green building. Analytical model is of great importance to describe and predict heat transfer with phase change. The classic Stefan problem solution is quite suitable for crystalline materials, which requires the input of certain phase change temperature. However, many PCMs widely used, like paraffin, are semi-crystalline materials, which have a much larger phase changing temperature range compared with small molecule crystalline materials. It is important to appropriately model the phase change of semi-crystalline polymers for the application of PCM. Furthermore, in large spatial scale prediction, widely used semi-infinite plane model is usually quite suitable to explain initial heat transfer. Unfortunately, semi-infinite plane is not the same as real situation. In this paper, by using the temperature at the end of the phase change as the equivalent melting temperature, a heat transfer model for semi-crystalline organic PCM is constructed. Meanwhile, this model concerns the phase change in a limited region. This model can serve as a fast tool to predict the one-dimensional heat transfer with phase change in an explicit form. The model is validated by the results of simulations and experiments reported in the literature.

Hydrogen can be used as an environmentally friendly fuel to power vehicles, electric devices, and spacecraft with water vapor as the only emission. One associated challenge is the development of safe hydrogen storage systems. Hydrogen tanks and other hydrogen infrastructure elements will be exposed to both high-pressure hydrogen and cyclic stresses. In our work, 304 stainless steel specimens were precharged with hydrogen and subjected to rotational bending fatigue with a maximum stress amplitude of 90 ksi. A diffusion model was solved to approximate the concentration of hydrogen in the specimen at the time of the test. Contrary to our previous work with simple bending fatigue tests, hydrogen precharging actually increased rotational bending fatigue life from 28,074 (Sx = 7,430, N = 103) cycles to 91,513 (Sx = 40,209, N=32) cycles, a factor of approximately 3.25. This result demonstrates that the effect of hydrogen on fatigue life can be highly situational, and great care should be taken when designing systems that will be exposed to high-pressure hydrogen under fatigue conditions.