Conductivity, NMR and crystallographic study of N,N,N,N-tetramethylammonium dicyanamide plastic crystal phases : an archetypal ambient temperature plastic electrolyte material

N,N,N,N-Tetramethylammonium dicyanamide (Me₄NDCA) has been examined via differential scanning calorimetry (DSC), thermogravimetric analysis, conductivity, single crystal X-ray diffraction and ¹H nuclear magnetic resonance (NMR) analyses, and was found to be highly conductive in the solid state (σ =10−3 S cm⁻² at 420 K) and to also exhibit unusual plastic crystal behaviour. To investigate the correlation between such behaviour and the occurrence of molecular rotations in the crystal, ¹H NMR second moment measurements are compared with calculated values predicted from the crystal structure. While DSC analysis indicates a number of solid–solid transitions at ambient temperatures, subsequent ¹H NMR analysis of the Me₄N⁺ cation shows that a variety of rotational motions become active at low (<240 K) temperatures, and that such transitions in rotational states occur over a range of temperatures rather than in a sharp transition. Conductivity analysis reveals that between 320 K and 420 K the conductivity increases by more than six orders of magnitude in the solid state, in line with the transition of the Me₄N⁺ cation to a diffusive state, and that other phase transitions observed in this temperature range have no marked effect on the conductivity. Conduction in this solid state is therefore envisaged to involve a vacancy-diffusion model, involving Me₄N⁺ cation vacancies.

N,N-Dimethylpyrrolidinium hydroxide : a highly conductive solid material at ambient temperature

N,N-Dimethylpyrrolidinium hydroxide (P₁₁OH·4H₂O) was found to exhibit high ionic conductivity in the solid state (7 × 10⁻³ S cm⁻¹ at 25°C) and unusual thermal properties, and ²H solid state NMR measurements indicate liquid-like mobility of the deuterium species in the solid state of P₁₁OD·4.5D₂O.

Using the psychrometric chart in building measurements

This paper centres around the presentation of multiple measured results on a psychrometric chart. The psychrometric chart was programmed in Microsoft Office Excel to accommodate measured results. It was written because existing programs appear not to cater for the researcher wishing to enter results electronically onto the chart. Furthermore, many existing charts are complex and cluttered displaying up to ten attributes, being intended for engineering design, whereas presenting the behaviour of living and working environments is focused on wet and dry bulb temperature and relative humidity. As well as results, users would also like to specify and adjust the ‘comfort zone’ (a shaded area on the chart) for different ‘adaptive’ or ‘seasonal’ conditions. The comfort zone is bounded by lines of constant heat loss from the skin, relative humidity and wet-bulb temperature. The paper presents various applications of the psychrometric chart for the analysis and reporting of research and discusses the programming of Microsoft Office Excel to generate the chart and display user data.

Investigating glazing system simulated results with real measurements

Over the past decades there has been a great deal of research related to simulation programs that calculate glazing thermal performance. In this study, several glazing systems were designed using VISION 3 (University of Waterloo, 1992) and WINDOW-6 (Lawrence Berkeley National Laboratory, 2010). The systems were fabricated and experimentally tested in-situ for a summer month. It was found that in most cases the predicted results of the glass temperature matched those measured, though slight discrepancies were observed during periods of high solar radiation, particularly for more complex systems and systems with shading devices.

Preliminary tools assisting collected building performance measurements

Investigating on-site building performance in architectural science is increasing. However, the simplest forms of measurement often lack any analytical support other than presentation on a time-series plot. Here, we present instrumentation and analytical tools to assist in reporting building performance. The intention is to explore formats for observing performance of buildings based on collected data. Sometimes data are presented directly, but more often, information is revealed by calculation. We introduce examples of tools pertaining to interior-exterior climatic comparisons, occupant comfort and thermal performance, such as weather data plotted against a neutral temperature so that adaptive model comfort tolerances can be illustrated. We plot the interior and exterior air condition on the ASHRAE psychrometric chart to understand conditioning requirements. Other tools calculate the ISO 7730 (Fanger) comfort model, and an adaptive model of comfort is provided for the interior measurements alongside an 80 – 90% comfort band. These tools add value to reporting data by displaying in several formats, so the researcher can observe and report quickly and clearly on the potential of various conditioning periods within a building.A case study is presented for a house in Darwin during the wet-season.

Temperature conditions during 'cold' sheet metal stamping

This paper investigates the friction and deformation-induced heating that occurs during the stamping of high strength sheet steels, under room temperature conditions. A thermo-mechanical finite element model of a typical plane strain stamping process was developed to understand the temperature conditions experienced within the die and blank material; and this was validated against experimental measurements. A high level of correlation was achieved between the finite element model and experimental data for a range of operating conditions and parameters. The model showed that the heat generated during realistic production conditions can result in high temperatures of up to 108 °C and 181 °C in the blank and die materials, respectively, for what was traditionally expected to be 'cold' forming conditions. It was identified that frictional heating was primarily responsible for the peak temperatures at the die surface, whilst the peak blank temperatures were caused by a combination of frictional and deformation induced heating. The results provide new insights into the local conditions within the blank and die, and are of direct relevance to sheet formability and tool wear performance during industrial stamping processes. © 2014 Elsevier B.V. All rights reserved.

Demo abstract: wind measurements for water quality studies in urban reservoirs

Water quality monitoring and prediction are critical for ensuring the sustainability of water resources which are essential for social security, especially for countries with limited land like Singapore. For example, the Singapore government identified water as a new growth sector and committed in 2006 to invest S$ 330 million over the following five years for water research and development [1]. To investigate the water quality evolution numerically, some key water quality parameters at several discrete locations in the reservoir (e.g., dissolved oxygen, chlorophyll, and temperature) and some environmental parameters (e.g., the wind distribution above water surface, air temperature and precipitation) are used as inputs to a three-dimensional hydrodynamics-ecological model, Estuary Lake and Coastal Ocean Model - Computational Aquatic Ecosystem Dynamics Model (ELCOM-CAEDYM) [2]. Based on the calculation in the model, we can obtain the distribution of water quality in the whole reservoir. We can also study the effect of different environmental parameters on the water quality evolution, and finally predict the water quality of the reservoir with a time step of 30 seconds. In this demo, we introduce our data collection system which enables water quality studies with real-time sensor data.