Grain Size Distributions after Single Hit Deformation of a Segregated, Commercial Nb-Containing Steel: Prediction and Experiment

The present investigation examines the applicability of the Dutta–Sellars equations in predicting the recrystallized grain sizes following deformation for a 0.046 wt pct Nb-bearing, commercially produced steel with a segregated solute content (from continuous casting). The investigation considered initial unimodal and bimodal grain size distributions before deformation that were generated by reheating the steel to 1498 K and 1423 K (1225 °C and 1150 °C), respectively. It was found that the reheated grain size distribution (separated into grain size classes) could be related to the solute-rich (smaller grain size classes) and solute-depleted (larger grain size classes) regions. The use of these relationships and a simple halving of the grain size within the distribution on recrystallization (used previously for homogenized samples of this steel) were found to be appropriate in the grain size class-based use of the Dutta–Sellars equations with respect to mode and maximum grain sizes after hot deformation and holding. This approach successfully predicted (confirmed by experiment) the grain size distribution after deformation in the presence of Nb segregation from continuous casting.     

The user model-based summarize and refine approach improves information presentation in spoken dialog systems

A common task for spoken dialog systems (SDS) is to help users select a suitable option (e.g., flight, hotel, and restaurant) from the set of options available. As the number of options increases, the system must have strategies for generating summaries that enable the user to browse the option space efficiently and successfully. In the user-model based summarize and refine approach (UMSR, Demberg and Moore, 2006), options are clustered to maximize utility with respect to a user model, and linguistic devices such as discourse cues and adverbials are used to highlight the trade-offs among the presented items. In a Wizard-of-Oz experiment, we show that the UMSR approach leads to improvements in task success, efficiency, and user satisfaction compared to an approach that clusters the available options to maximize coverage of the domain (Polifroni et al., 2003). In both a laboratory experiment and a web-based experimental paradigm employing the Amazon Mechanical Turk platform, we show that the discourse cues in UMSR summaries help users compare different options and choose between options, even though they do not improve verbatim recall. This effect was observed for both written and spoken stimuli.     

Nuclear renaissance,public perception and design criteria: An exploratory review

There is currently an international drive to build new nuclear power plants, bringing about what is being termed a “nuclear renaissance”. However, the public perception of nuclear energy has historically been, and continues to be, a key issue, particularly in light of the Fukushima nuclear incident. This paper discusses the disparity between perceived and calculated risks based on the last four decades of research into risk perception. The leading psychological and sociological theories, Psychometric Paradigm and Cultural Theory, respectively, are critically reviewed. The authors then argue that a new nuclear-build policy that promotes a broader approach to design incorporating a wider range of stakeholder inputs, including that of the lay public, may provide a means for reducing the perceived risk of a nuclear plant. Further research towards such a new approach to design is proposed, based on integrating expert and lay stakeholder inputs and taking into account broader socio-cultural factors whilst maintaining the necessary emphasis on safety, technological development, economics and environmental sustainability.     

Control of grain size and -orientation in multi-crystalline silicon ingots

Two different cooling rates have been imposed during the early solidification of two multi-crystalline silicon ingots with 250mm diameter and 100mm height in a pilot scale directional solidification furnace. This has been done by opening a variable heat leak system below the crucible in order to achieve a high initial cooling rate in one of the ingots. The grain-structure and -orientation of these two ingots have been investigated by light microscopy (LM) and electron backscattered diffraction (EBSD), and their electrical properties by quasi-steady state photo-conductance (QSSPC) and surface photovoltage (SPV) method. The ingot with the high initial cooling rate shows predominantly grains which are significantly larger than what is usually found in mc-Si. The minority carrier diffusion lengths measured on the large grains in the ingot with high cooling rate show higher values than those measured on the ingot with smaller grains. These results indicate that principles of grain size and -orientation control in mc-Si ingots can be applied to a pilot scale furnace, and the potential for up-scaling to industrial ingots with improved electrical properties and, thus, higher solar cell conversion efficiency.     

Strain Dependence of the Uniaxial Compression Response of Vegetable Shortening

Many soft food materials, including vegetable shortening, exhibit complex rheological behavior. For shortening, a precise determination of rheological behavior is necessary to understand its functionality as a food ingredient. Commercial vegetable shortening was subjected to monotonic and cyclic uniaxial compression tests at a wide range of loading rates. The elastic modulus determined from unloading was a function of strain, varying between 740 kPa in the shortening’s strain hardening region to 220 kPa at large strain where perfect plasticity had developed. Visual analysis of shortening specimens during the compression process showed that a rate-dependent stress overshoot was attributable to the development of a shear band following strain hardening. An elastoviscoplastic constitutive model was developed to define the complex rate-dependent compression response of vegetable shortening. Using the fundamental parameters obtained from the different types of compression tests, the proposed model accurately predicted the uniaxial compression response of vegetable shortening over a wide range (three decades) of compression rates. A model with predictive capabilities of large strain properties is desirable because shortening is subject to large strain in essentially all applications.     

Tuning Carbon Materials for Supercapacitors by Direct Pyrolysis of Seaweeds

The sea provides a large variety of seaweeds that, because of their chemical composition, are fantastic precursors of nanotextured carbons. The carbons are obtained by the simple pyrolysis of the seaweeds under a nitrogen atmosphere between 600 and 900 °C, followed by rinsing the product in slightly acidic water. Depending on the origin of the seaweed and on the pyrolysis conditions, the synthesis may be oriented to give an oxygen‐enriched carbon or to give a tuned micro/mesoporous carbon. The samples with a rich oxygenated surface functionality are excellent as supercapacitor electrodes in an aqueous medium whereas the perfectly tuned porous carbons are directly applicable for organic media. In both cases, the specific surface area of the attained carbons does not exceed 1300 m² g⁻¹, which results in high‐density materials. As a consequence, the volumetric capacitance is very high, making these materials more interesting than activated carbons from the point of view of developing small and compact electric power sources. Such versatile carbons, obtained by a simple, ecological, and cheap process, could be well used for environment remediation such as water and air treatment.     

Early manifestations of personality and adult health: A life course perspective.

Objective: The aim of this study is to investigate whether individual personality or temperamental qualities that emerge early and persist over the life course, predict adult midlife health. Specific childhood personality attributes considered include distress proneness, behavioral inhibition, and ability to stay focused on a task. Design: Prospective data are from 569 individuals followed from birth into adulthood. Main Outcome Measures: Outcomes include two different measures of adult health: self-rated general health, and number of illnesses in adulthood. Results: Childhood personality attributes related to attention and distress were significantly associated with adult health, with stronger effects evident among women. Children with high attention reported better self-rated health (b = 0.12, p