Application of hyperspectral vegetation indices to detect variations in high leaf area index temperate shrub thicket canopies

Accurate measurement of leaf area index (LAI), an important characteristic of plant canopies directly linked to primary production, is essential for monitoring changes in ecosystem C stocks and other ecosystem level fluxes. Direct measurement of LAI is labor intensive, impractical at large scales and does not capture seasonal or annual variations in canopy biomass. The need to monitor canopy related fluxes across landscapes makes remote sensing an attractive technique for estimating LAI. Many vegetation indices, such as Normalized Difference Vegetation Index (NDVI), tend to saturate at LAI levels > 4 although tropical and temperate forested ecosystems often exceed that threshold. Using two monospecific shrub thickets as model systems, we evaluated the potential of a variety of algorithms specifically developed to improve accuracy of LAI estimates in canopies where LAI exceeds saturation levels for other indices. We also tested the potential of indices developed to detect variations in canopy chlorophyll to estimate LAI because of the direct relationship between total canopy chlorophyll content and LAI. Indices were evaluated based on data from direct (litterfall) and indirect measurements (LAI-2000) of LAI. Relationships between results of direct and indirect ground-sampling techniques were also evaluated. For these two canopies, the indices that showed the highest potential to accurately differentiate LAI values > 4 were derivative indices based on red-edge spectral reflectance. Algorithms intended to improve accuracy at high LAI values in agricultural systems were insensitive when LAI exceeded 4 and offered little or no improvement over NDVI. Furthermore, indirect ground-sampling techniques often used to evaluate the potential of vegetation indices also saturate when LAI exceeds 4. Comparisons between hyperspectral vegetation indices and a saturated LAI value from indirect measurement may overestimate accuracy and sensitivity of some vegetation indices in high LAI communities. We recommend verification of indirect measurements of LAI with direct destructive sampling or litterfall collection, particularly in canopies with high LAI.     

Stone Weathering in a Photograph

The appearance of weathering effects on stone is important for creating outdoor scenes in computer graphics. To achieve them, previous research has built upon physical simulation, which, while yielding a degree of realism, is computationally expensive and inapplicable to the situation when the object geometry is unknown. Also, physical simulation requires specific knowledge of the stone properties and environmental processes. In this paper, we present a simple visual simulation pipeline for creating weathering effects on stone within a single image. Two primary effects of stone weathering, i.e., smoothing and roughening, are considered. In addition, erosion on the object silhouette is treated. These challenging effects involve significant geometry changes, which are intractable for previous image‐based editing techniques. The effectiveness of our technique is illustrated on a variety of scenes and types of stone. While it can be fully automatic, it also allows easy user interaction.     

Atom probe crystallography: characterization of grain boundary orientation relationships in nanocrystalline aluminium

Spatial Distribution Maps (SDM) in their various forms have previously been used to identify and characterize crystallographic structure within APT reconstructions. Importantly, it has been shown that such SDM analyses can also provide the crystallographic orientation of the specimen with respect to the direction of the detector in the original experiment. In this study, we investigate the application of SDMs to the analysis of APT reconstruction of a nanocrystalline Al film. We demonstrate that significant intra-granular crystallographic information is retained in the reconstruction, even in the x-y plane perpendicular to the direction of the detector. Further, the crystallographic orientation of the grains can be characterized highly accurately not only with respect to the bulk specimen but also their misorientation with respect to neighbouring grains.     

Water quality management of aquifer recharge using advanced tools

Managed aquifer recharge (MAR) with recycled water or other alternative resources is one of the most rapidly growing techniques that is viewed as a necessity in water-short areas. In order to better control health and environmental effects of MAR, this paper presents two case studies demonstrating how to improve water quality, enable reliable tracing of injected water and better control and manage MAR operation in the case of indirect and direct aquifer recharge. Two water quality management strategies are illustrated on two full-scale case studies, including the results of the combination of non conventional and advanced technologies for water quality improvement, comprehensive sampling and monitoring programs including emerging pollutants, tracer studies using boron isotopes and integrative aquifer 3D GIS hydraulic and hydrodispersive modelling.     

Synthesis and performance evaluation of thin film PPy-PVDF multilayer electroactive polymer actuators

Bending-type microactuators less than 1 mm in length and comprising of two polypyrrole (PPy) layers separated by polyvinylidene fluoride (PVDF) membrane have previously been fabricated and was shown to operate both in air and aqueous media. The main limiting factor to increase the bending angle and to further miniaturise these actuators was the thickness of the commercially-available PVDF membrane used (～110 μm). In this study, we have synthesised a porous PVDF thin film with a thickness of 32 μm using a spin coating technique, and electrochemically deposited PPy layers on both sides of this thin film to make ultra thin film polymer actuators. The electromechanical and electrochemical properties are investigated and compared with those of the thicker actuator system using the commercially-available PVDF and under identical conditions. The thin film shows very promising performance compared to its thicker counterpart.     

Ink‐jet‐printable phosphorescent organic light‐emitting‐diode devices

Abstract— A novel method for the fabrication of ink‐jet‐printed organic light‐emitting‐diode devices is discussed. Unlike previously reported solution‐processed OLED devices, the emissive layer of OLED devices reported here does not contain polymeric materials. The emission of the ink‐jet‐printed P²OLED (IJ‐P²OLED) device is demonstrated for the first time. It shows good color and uniform emission although it uses small‐molecule solution. Ink‐jet‐printed green P²OLED devices possess a high luminous efficiency of 22 cd/A at 2000 cd/m² and is based on phosphorescent emission. The latest solution‐processed phosphorescent OLED performance by spin‐coating is disclosed. The red P²OLED exhibits a projected LT50 of >53,000 hours with a luminous efficiency of 9 cd/A at 500 cd/m². The green P²OLED shows a projected LT50 of >52,000 hours with a luminous efficiency of 35 cd/A at 1000 cd/m². Also discussed is a newly developed sky‐blue P²OLED with a projected LT50 of >3000 hour and a luminous efficiency of 18 cd/A at 500 cd/m².     

Ultrasonic mineralization of a reactive textile azo dye, remazol black B

The degradation of a reactive black dye in oxygen saturated aqueous solution has been investigated using a high frequency ultrasonic generator. The ˙OH radical initiated oxidative degradation of the dye results in 65% mineralization as measured by the decrease in the total organic content. Ion chromatography indicates that the only remaining components are oxalate, sulfate and nitrate ions.     

Studying a Niche Market: UK Students and the Private Rented Sector

Renting privately is a minority tenure in the UK, but the sector is recognised as being essential to the smooth operation of the wider housing market. The need to target policy effectively has led to an increasing stress on the importance of understanding how local private rental markets operate. Using a number of local case study areas from throughout the country, this paper explores the nature of demand for private rented housing from students. This niche market is a substantial and growing feature of the private rented sector. The paper demonstrates that although student demand shares a number of common characteristics throughout the UK, its localised impacts can vary. Both qualitative and quantitative methods are required to gain an understanding of how student demand affects all aspects of the local housing market, and it is concluded that greater attention needs to be paid to exploring ways of understanding the dynamics of rental market development.