A Practical and Controllable Hair and Fur Model for Production Path Tracing

We present an energy‐conserving fiber shading model for hair and fur that is efficient enough for path tracing. Our model adopts a near‐field formulation to avoid the expensive integral across the fiber, accounts for all high order internal reflection events with a single lobe, and proposes a novel, closed‐form distribution for azimuthal roughness based on the logistic distribution. Additionally, we derive, through simulation, a parameterization that relates intuitive user controls such as multiple‐scattering albedo and isotropic cylinder roughness to the underlying physical parameters.     

Thermal transients during processing of materials by very high power ultrasonic additive manufacturing

Dynamic recrystallisation at interfaces has been suggested as the bonding mechanism in the joining of metallic tapes, during very high power ultrasonic additive manufacturing. To understand the reasons for such occurrence of dynamic recrystallization, thermal transients from the interface regions were recorded during processing of aluminum alloy (3003 and 6061 series) and 11 000 copper tapes under similar conditions. Measurements in 3003 Al were also carried out for different processing parameters. Measured peak temperatures were seen to increase with increase in shear strength of the material and ultrasonic vibration amplitude. The observations have been rationalized based on interfacial heating at asperities due to adiabatic plastic deformation.     

Polymer nanocomposites based on transition metal ion modified organoclays

A unique class of nanocomposites containing organoclays modified with catalytically active transition metal ions (TMI) and ethylene vinyl acetate (EVA) copolymers was prepared. The morphology, thermal and rheological properties of these nanocomposites were studied by thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), extended X-ray absorption fine structure (EXAFS) spectroscopy, X-ray scattering/diffraction and oscillatory shear rheometry. TMI-modified organoclays were thought to possess pillaring of multivalent TMI in the interlayer silicate gallery, leading to a notable reduction of the interlayer d-spacing. The resulting nanocomposites exhibited significantly improved thermal stability and fire retardation properties, but similar morphology (i.e., an intercalated-exfoliated structure) and rheological properties comparable with EVA nanocomposites containing unmodified organoclays. It appears that the compressed organic component in the TMI-modified organoclay can still facilitate the intercalation/exfoliation processes of polymer molecules, especially under extensive shearing conditions. The improved fire retardation in nanocomposites with TMI-modified organoclays can be attributed to enhanced carbonaceous char formation during combustion, i.e., charring promoted by the presence of catalytically active TMI.     

A pathway for net-zero energy buildings: creating a case for zero cost increase

To have market relevance and gain widespread market adoption, zero energy buildings (ZEBs) will need to be designed and constructed cost-effectively, and preferably without additional costs. An approach was developed to create low-energy buildings without additional construction costs such that it yielded innovation in building technology and integration by the market. A case study of the implementation of this method is presented to provide a data point that ZEBs can be built with zero cost increase. Documenting cost-control best practices and packaging those strategies for adoption by the commercial building sector will help make the business case for ZEBs for mainstream construction and promote market uptake of the innovative technologies and design approaches needed. The holistic implementation of cost-control strategies will enable ZEBs to be designed and constructed on a typical budget. The current state of ZEB economics is evaluated and a path forward is proposed for greater market penetration of ZEBs. By demonstrating how to combine ZEB technologies and design approaches into an overall efficiency package that can be implemented at minimal (zero, in certain cases) incremental capital cost, the domain of ZEB design and construction can be expanded from a niche market to the commercial construction mainstream.     

Overheating in care settings: magnitude,causes, preparedness and remedies

ABSTRACT

Research in UK and elsewhere has highlighted that older people are particularly vulnerable to negative health effects of overheating. This paper examines the magnitude, causes, preparedness and remedies for addressing the risk of summertime overheating in four case study residential care and extra-care settings across the UK, spanning different building types, construction and age. An interdisciplinary approach is adopted, drawing from building science and social science methods, including temperature monitoring, building surveys, and interviews with design and management teams. The findings suggest that overheating is a current and prevalent risk in the case study schemes, yet currently little awareness or preparedness exists to implement suitable and long-term adaptation strategies (e.g., external shading). There was a perception from designers to managers, that cold represents a bigger threat to older occupants’ health than excessive heat. A lack of effective heat management was found across the case studies that included unwanted heat gains from the heating system, confusion in terms of responsibilities to manage indoor temperatures, and conflicts between window opening and occupant safety. Given that care settings should provide protection against risks from cold and hot weather, design, management and care practices need to become better focused towards this goal.     

General contribution of nonspecific interactions to fluorescence intensity

Many chemical compounds, including nonfluorescent ones, induce changes in the fluorescence spectra of certain probes, such as berberine cation and Reichardt's betaine, both in the absence and the presence of solvent, that affect almost exclusively emission intensity. In this work, the application of fluorescence detection by intensity changes (FDIC) to HPLC and TLC chromatographic systems with fluorescence detectors has been studied. FDIC detection is of special interest in detecting nonfluorescent analytes, either in HPLC or in TLC mode. It does not involve covalent interactions, and the dielectric permittivity (epsilon) of the medium plays an important role. The balance between nonspecific and specific interactions produces either an increase or a decrease in fluorescence intensity. Therefore, the influence of chromatographic conditions and chemical structure of analytes on the sign and magnitude of fluorescence peaks for sample detection in HPLC and TLC systems has been discussed. In general, probe nature and concentration determine response and detection sensitivity for a given sample in TLC and HPLC. As solubility and fluorescence properties in solvents determine the operating conditions for a FDIC probe in HPLC mode, nature and flows of mobile phase and solvent are important for chromatographic response and detection sensitivity.     

Controlling self-assembled perovskite-spinel nanostructures

We report a discovery that self-assembled perovskite-spinel nanostructures can be controlled simply by selecting single-crystal substrates with different orientations. In a model BiFeO(3)-CoFe(2)O(4) system, a (001) substrate results in rectangular-shaped CoFe(2)O(4) nanopillars in a BiFeO(3) matrix; in contrast, a (111) substrate leads to triangular-shaped BiFeO(3) nanopillars in a CoFe(2)O(4) matrix, irrespective of the volume fraction of the two phases. This dramatic reversal is attributed to the surface energy anisotropy as an intrinsic property of a crystal.     

Reactive flow in silicon electrodes assisted by the insertion of lithium

In the search for high-energy density materials for Li-ion batteries, silicon has emerged as a promising candidate for anodes due to its ability to absorb a large number of Li atoms. Lithiation of Si leads to large deformation and concurrent changes in its mechanical properties, from a brittle material in its pure form to a material that can sustain large inelastic deformation in the lithiated form. These remarkable changes in behavior pose a challenge to theoretical treatment of the material properties. Here, we provide a detailed picture of the origin of changes in the mechanical properties, based on first-principles calculations of the atomic-scale structural and electronic properties in a model amorphous silicon (a-Si) structure. We regard the reactive flow of lithiated silicon as a nonequilibrium process consisting of concurrent Li insertion driven by unbalanced chemical potential and flow driven by deviatoric stress. The reaction enables the material to flow at a lower level of stress. Our theoretical model is in excellent quantitative agreement with experimental measurements of lithiation-induced stress on a Si thin film.     

New Insights into the Quality of Urban Storm Water in South Eastern Australia

Quantifying the quality of urban storm water is an important prerequisite to the effective management of urban runoff, which is recognized as the major nonpoint source of pollution in urban areas. Although data on urban storm-water quality are widely available, they are often based on relatively limited data sets, usually containing few samples per event and/or few events per catchment. This paper reports on a large scale monitoring of the key storm-water pollutants found in urban discharges during both wet and dry weather from seven urban catchments in South Eastern Australia. The catchments are all separately sewered (with wholly piped systems) with varying sizes and land uses. Using the same monitoring technique, between 16 and 52 pollutographs were captured at each site for total suspended solid (TSS), total phosphorus, and total nitrogen (TN), while event mean concentrations (EMCs) of heavy metals and major ions, as well as species of N and P, were recorded at a subset of sites. It was found that EMCs of TSS were around 50% less than have been typically reported in earlier literature. During wet weather, nutrients were similar to previously reported, as were most metals concentrations. However, zinc concentrations were significantly higher than previously reported. EMCs of TSS were higher during storm flows than in baseflow, while TN concentrations were consistently higher during baseflow. EMCs of all pollutants monitored were poor with simple hydrological parameters (e.g., event rainfall depth); however, event pollution loads correlated very well with the rainfall intensity to a power, summed over the event duration. It was not possible to distinguish an impact of land use on pollutant concentrations. The first-flush effect was found not to be significant at all sites except the smallest catchment with the simplest drainage layout (the roof of a large building). All these findings have significant implication for treatment strategies with the significantly lower than previously observed TSS requiring consideration in future modeling and treatment design.     

Microstructures and Grain Refinement of Additive-Manufactured Ti-xW Alloys

Metallurgical and Materials Transactions A - It is necessary to better understand the composition–processing–microstructure relationships that exist for materials produced by additive...