Water and air transmissivity of geotextiles

The in-plane flow characteristics of both water and air in needled, nonwoven geotextiles have been evaluated in this study. Transmissivity (equal to permeability times fabric thickness) versus applied normal stress on the fabric has been measured in a radial flow device for different fabrics and for different thicknesses of a given fabric. The transmissivity response in each case was seen to decrease with increasing stress until a residual value was reached. In none of the cases did the fabric compress to the point where flow was completely shut off, even though stress levels of 2500 psf were applied. In turn, the calculated geotextile permeability varied from a fine gravel to a medium sized sand.Planar air flow in geotextiles has been found to be in excess of two orders of magnitude greater than water flow under comparable conditions. Air flow through partially and fully saturated fabrics is shown to be of little practical interest since the air easily moves around the water in the fabric voids or displaces it entirely.The need for transmissivity test standardization for all types of geotextiles and geotextile composite systems is expressed.     

Abnormal carbohydrate metabolism in amyotrophic lateral sclerosis and Parkinsonism-dementia on Guam

Amyotrophic lateral sclerosis and Parkinsonism-dementia are unusually prevalent on Guam. Carbohydrate metabolism was studied in 110 patients with evidence diagnostic of or suspecious for these diseases. The combined incidence of known diabetes in 29 per cent of them plus a high percentage of glucose tolerance tests interpreted as abnormal, even when most age-related criteria were considered, was considerably higher than the incidence of abnormal carbohydrate metabolism reported elsewhere in the general population of the United States, the tropical Pacific area, or in recent surveys on Guam itself. The diabetes was generally mild in nature and noteworthy for a lack of retinopathy and other complications. Hypertension, hypercholesterolemia, and hyperuricemia, although highly prevalent, were not consistently associated with abnormal glucose metabolism. Similarly, no consistent association was demonstrated with such factors as age, muscle atrophy, or physical activity.     

Digitally Crafted Couture

Clothing could be described as architecture in motion. Julia Koerner , a designer based between Salzburg and Los Angeles, operates at the crossroads between architecture and product design. She has recently been working on a number of projects in the couture field, both independently and in collaboration. Here she describes how these creations – largely inspired by the forms and growth patterns of nature – have utilised various additive manufacturing techniques to explore the possibilities of folding, nesting and smocking in digital space. From seamlessness to the ability to adapt to temperature, light and emotion, these garments appear to naturally grow on the body or to animate it.     

Development of permanent magnet MnAlC/polymer composites and flexible filament for bonding and 3D-printing technologies

Searching for high-performance permanent magnets components with no limitation in shape and dimensions is highly desired to overcome the present design and manufacturing restrictions, which affect the efficiency of the final devices in energy, automotive and aerospace sectors. Advanced 3D-printing of composite materials and related technologies is an incipient route to achieve functional structures avoiding the limitations of traditional manufacturing. Gas-atomized MnAlC particles combined with polymer have been used in this work for fabricating scalable rare earth-free permanent magnet composites and extruded flexible filaments with continuous length exceeding 10 m. Solution casting has been used to synthesize homogeneous composites with tuned particles content, made of a polyethylene (PE) matrix embedding quasi-spherical particles of the ferromagnetic τ-MnAlC phase. A maximum filling factor of 86.5 and 72.3% has been obtained for the composite and the filament after extrusion, respectively. The magnetic measurements reveal no deterioration of the properties of the MnAlC particles after the composite synthesis and filament extrusion. The produced MnAlC/PE materials will serve as precursors for an efficient and scalable design and fabrication of end-products by different processing techniques (polymerized cold-compacted magnets and 3D-printing, respectively) in view of technological applications (from micro electromechanical systems to energy and transport applications).     

Effect of polymer–nanoparticle interactions on the glass transition dynamics and the conductivity mechanism in polyurethane titanium dioxide nanocomposites

We report on the glass transition dynamics and the conductivity properties of a nanodielectric system composed of pre-synthesized TiO₂ nanoparticles embedded in thermoplastic polyurethane. Increase of TiO₂ loading results in enhanced segmental mobility of the composites and less steep temperature dependence, i.e., lower fragility index. The decrease in the fragility index and glass transition temperature is discussed based on the FTIR results. We observe different behavior of conductivity for temperatures above and below the glass transition temperature. At high temperatures the composites exhibit conductivity values more than 2 orders of magnitude higher than those in the pristine matrix. At the same time, at sub-T_g temperatures composites are characterized by superior electrical insulation properties compared to pristine matrix material. Such drastic temperature dependence of the conductivity/insulating ability of the flexible and light-weight, low-T_g composite material can be utilized in various applications including sensing and temperature switching materials.