First-principles data for solid-solution strengthening of magnesium: From geometry and chemistry to properties

Solid-solution strengthening results from solutes impeding the glide of dislocations. Existing theories of strength rely on solute/dislocation interactions, but do not consider dislocation core structures, which need an accurate treatment of chemical bonding. Here, we focus on strengthening of Mg, the lightest of all structural metals and a promising replacement for heavier steel and aluminum alloys. Elasticity theory, which is commonly used to predict the requisite solute/dislocation interaction energetics, is replaced with quantum-mechanical first-principles calculations to construct a predictive mesoscale model for solute strengthening of Mg. Results for 29 different solutes are displayed in a “strengthening design map” as a function of solute misfits that quantify volumetric strain and slip effects. Our strengthening model is validated with available experimental data for several solutes, including Al and Zn, the two most common solutes in Mg. These new results highlight the ability of quantum-mechanical first-principles calculations to predict complex material properties such as strength.     

Multi-zone simulation of outdoor particle penetration and transport in a multi-story building

In areas with poor ambient air quality, indoor particle concentrations can be significantly affected by particulate matter originating outdoors. The indoor environments of multi-zone and multi-story buildings are affected differently by outdoor particles compared with single-family houses, because of the buildings’ more complicated airflow characteristics. The objective of this study is to analyze outdoor particle penetration and transport, and their impact on indoor air, in a multi-zone and multi-story building using a CONTAMW simulation. For the airflow and particle transport analysis, the building leakage, penetration coefficients, and deposition rates were determined by on-site experiments. The results of airflow simulations for cold winters show that outdoor air infiltrates through the lower part of building and exfiltrates from the upper part. The results of the particle simulation also indicated that the airflow characteristics, combined with deposition rates, cause the lower floors of a multi-story building to be exposed to higher fine particle concentrations compared with the upper floors of the building. The study demonstrated that the CONTAMW simulation can be useful in analyzing the impact of outdoor particles on indoor environments through the identification of key particle transport parameters and validated airflow simulations.     

Can we ‘Catch ‘em All’? An exploration of the nexus between augmented reality games,urban planning and urban design

Urban planners and designers have spent the last 50 years trying to activate unused public spaces, create walkable cities and encourage sociability through urban design. Pokémon Go has succeeded, almost overnight, to entice people of all demographics into the streets of cities around the world. In fact, many previously underutilized public spaces have suddenly become hot spots for all demographics, playing Pokémon Go and other similar augmented reality games (ARGs). While anecdotally it seems that ARGs activate public spaces, increase community interactions and facilitate exploration of urban spaces, little study has been done on the influence of ARGs on sense of place, or the way in which these games are influencing player engagement with the public spaces they are playing within. This paper reports the findings of a survey of 994 Australian players. The paper explores whether ARGs affect user needs being met in public spaces, and the implications of these findings for urban practitioners.     

浅谈工业区市政工程详规的编制

市政详规在整个规划设计周期中处于承上启下、把蓝图变为现实的结合点,既需要有规划的前瞻性,又要求有指导下一步设计的可操作性。但国内目前尚无针对市政工程详细规划的技术规范或标准用以指导市政详规的设计工作。结合项目实践,探讨了当前工业区市政详规阶段的工作特点、难点和重点,以期与同行交流获益。     

Manufacturing interoperability using a semantic mediation

Globalization has become a major trend in today’s business environment, which has led to the explosion in the amount of information shared amongst business partners. It is critical to share information correctly, inexpensively, and effectively for accomplishing business goals using global information sharing architectures under increasing pressure of competitive markets. One of the major barriers to build such a global information sharing architecture is caused by the absence of universally accepted ontology needed to facilitate business partners to be seamlessly interoperable with one another within a global manufacturing world. In reality, due to heterogeneous enterprise environments in which business partners find themselves, multiple ontologies are defined and used. In this paper, we present a method for semantically mapping different business documents to a conforming document format, given inevitable existence of multiple ontolgoies. Forward reasoning rules are used to express the mapping, and they are applied to exchange messages between heterogeneous business partners. We demonstrate our semantic mapping approach by using a demonstrator that uses Web services for service components and the Jena package for a reasoning engine. A business scenario of the demonstrator consists of a part ordering transaction taking place between an original equipment manufacturer and its supplier. This approach can also be applied to other manufacturing operations such as parts scheduling, order sequencing, and inventory.     

Spatially-Resolved Calorimetry: Using IR Thermography to Measure Temperature and Trapped NOX Distributions on a NOX Adsorber Catalyst

Palladium catalysts supported on CeO_2, Ce_0.75Zr_0.25O₂, ZrO_2, TiO₂, Nb₂O₅, Al₂O₃ were studied on the total oxidation of butyl carbitol. Several techniques were used to characterize the samples such as diffuse reflectance spectroscopy (DRS), temperature programmed reduction (TPR), cyclohexane dehydrogenation and CO temperature programmed desorption (TPD). DRS and TPR results revealed the presence of bulk PdO and PdO with strong interaction with the support. The catalytic tests showed the following order for decreasing activity: Pd/Ce_0.75Zr_0.25O₂ > Pd/CeO₂ > Pd/TiO₂ > Pd/Nb₂O₅ > Pd/Al₂O₃ > Pd/ZrO₂. However, when the turnover frequency (TOF) was calculated, all the samples had similar values.     

Low-temperature synthesis of indium tin oxide nanowires as the transparent electrodes for organic light emitting devices

Low-temperature growth of indium tin oxide (ITO) nanowires (NWs) was obtained on catalyst-free amorphous glass substrates at 250?°C by Nd:YAG pulsed-laser deposition. These ITO NWs have branching morphology as grown in Ar ambient. As suggested by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), our ITO NWs have the tendency to grow vertically outward from the substrate surface, with the (400) plane parallel to the longitudinal axis of the nanowires. These NWs are low in electrical resistivity (1.6×10?? Ω cm) and high in visible transmittance (~90–96%), and were tested as the electrode for organic light emitting devices (OLEDs). An enhanced current density of ~30 mA cm?2 was detected at bias voltages of ~19–21 V with uniform and bright emission. We found that the Hall mobility of these NWs is 2.2–2.7 times higher than that of ITO film, which can be explained by the reduction of Coulomb scattering loss. These results suggested that ITO nanowires are promising for applications in optoelectronic devices including OLED, touch screen displays, and photovoltaic solar cells.     

Thermal and catalytic degradation of waste high-density polyethylene (HDPE) using spent FCC catalyst

Thermal and catalytic degradation using spent fluid catalytic cracking (FCC) catalyst of waste high-density polyethylene (HDPE) at 430 °C into fuel oil were carried out with a stirred semi-batch operation. The product yield and the recovery amount, molecular weight distribution and paraffin, olefin, naphthene and aromatic (PONA) distribution of liquid product by catalytic degradation using spent FCC catalyst were compared with those by thermal degradation. The catalytic degradation had lower degradation temperature, faster liquid product rate and more olefin products as well as shorter molecular weight distributions of gasoline range in the liquid product than thermal degradation. These results confirmed that the catalytic degradation using spent FCC catalyst could be a better alternative method to solve a major environmental problem of waste plastics. This paper is dedicated to Dr. Youn Yong Lee on the occasion of his retirement from Korea Institute of Science and Technology.     

Optimization of Praseodymium-Doped Cerium Pigment Synthesis Temperature

The development of red pigments is of great interest to the ceramic industry. Pr(IV) stabilization in a CeO₂ matrix yields materials with a red color. In this study, the traditional ceramic method involving solid-state reaction was used to prepare pigments in the system Ce_{1− x} Pr _x O_2−δ (0.005 ≤ x ≤ 0.1) from mixtures of rare-earth oxides. The chemical stability of these pigments was then determined in some industrial glazes. The glazing tests indicate that the powder samples calcined at 1200° and1300°C are unstable, whereas those calcined at 1400° and 1500°C are stable. These findings are related to the nonformation of a solid solution, to which the pigmenting power is attributed, in calcinations at temperatures below 1400°C.