Traditional irrigation and its importance to the tourist landscape of Valais, Switzerland

The contemporary landscape of the Central and Haut Valais, Switzerland, is partially a product of the ancient but extant bisse irrigation system. The current principal conduit network extends for approximately 760 kilometres, whilst the distribution network stretches for over 25 000 kilometres. Both systems have had a major impact on the Valaisan landscape. Besides this, traditional distribution techniques (ruissellement) have also altered dramatically the landscape of specific locations in the Valais. The contribution of bisses to the local milieu has been recognized by the federal, cantonal and communal governments. All three levels of government have provided incentives to farmers and local irrigation institutions to conserve traditional farming practices where appropriate and protect traditional methods of irrigation. This paper describes the landscape impact of traditional and modern irrigation practices and the instruments available for protecting these practices. It also appraises the success of these interventions and examines what future role bisses might play in protecting the current agricultural landscape, which has become so crucial to the success of summer tourism.     

Investigation of high-pressure micro jet technology as an alternative to diamond disc conditioning in ILD CMP

The efficacy of an alternative to conventional diamond conditioning in chemical mechanical planarization (CMP) was evaluated in this study. The high pressure micro jet (HPMJ) system sprays ultra-pure water (UPW) at pressures ranging from 10 to 20 MPa onto a CMP pad to clean the pad of slurry residue, remove embedded slurry particles, and re-establish pad asperities. The system is employed in an ex situ fashion and is compared to in situ and ex situ diamond conditioning as well as using no conditioning. Real-time frictional force acquisition allows for coefficient of friction (COF) analysis, which indicates the extent of pad wear. Removal rate analysis, SEM imagery, and pad surface profilometry are also used to evaluate HPMJ as an alternative conditioning technology. Removal rates significantly lower than those associated with diamond conditioning are obtained for the HPMJ system when UPW conditioning is directly followed by polishing. SEM imagery and pad profilimetry indicate these low HPMJ removal rates are due to differences in pad surface chemistry, not pad surface topography. Experiments including a 30 s silicon wafer polish with slurry following HPMJ conditioning to re-establish pad surface chemistry were performed and result in removal rates that are comparable to those obtained using ex situ conditioning. The removal rates obtained using HPMJ conditioning for relative wafer-platen velocities of 0.31 and 0.62 m/s are 8 and 1% higher than those obtained using ex situ diamond conditioning and 18% lower than those obtained using ex situ diamond conditioning for 0.93 m/s. The average COF values for HPMJ conditioning using the intermediate silicon wafer polishes are 15% lower than average COF values associated with ex situ diamond conditioning, suggesting a possible increase in pad life for the HPMJ system.     

Seasonal Anointment with Millipedes in a Wild Primate: A Chemical Defense Against Insects?

Members of a wild group of wedge-capped capuchin monkeys (Cebus olivaceus) intentionally anoint themselves with millipedes (Orthoporus dorsovittatus). Chemical analysis revealed these millipedes secrete two benzoquinones, compounds known to be potently repellent to insects. We argue that the secretion that rubs off on the monkeys in the course of anointment provides protection against insects, particularly mosquitoes (and the bot flies they transmit) during the rainy season. Millipede secretion is so avidly sought by the monkeys that up to four of them will share a single millipede. The anointment must also entail risks, since benzoquinones are toxic and carcinogenic. We suggest that for capuchins the immediate benefits of anointment outweigh the long-range costs.     

Reliability of thermal interface materials: A review

Thermal interface materials (TIMs) are used extensively to improve thermal conduction across two mating parts. They are particularly crucial in electronics thermal management since excessive junction-to-ambient thermal resistances can cause elevated temperatures which can negatively influence device performance and reliability. Of particular interest to electronic package designers is the thermal resistance of the TIM layer at the end of its design life. Estimations of this allow the package to be designed to perform adequately over its entire useful life. To this end, TIM reliability studies have been performed using accelerated stress tests. This paper reviews the body of work which has been performed on TIM reliability. It focuses on the various test methodologies with commentary on the results which have been obtained for the different TIM materials. Based on the information available in the open literature, a test procedure is proposed for TIM selection based on beginning and end of life performance.     

A comparative ab initio study of hydrogen abstraction from n-propyl benzene

Aromatics form an integral part of typical aviation fuels with n-propyl benzene selected as a representative molecule for inclusion in several EU and US surrogate blends used for design calculations. Despite the practical relevance, kinetic and thermodynamic data obtained using comparatively accurate ab initio methods have to date not been compared with currently used reaction class based estimates. The use of ab initio methods for comparatively complex molecules also necessitates an assessment of the relative benefits of higher levels of theory as it is typically desirable to balance the accuracy of the treatment of individual reactions with the need to consider more complete reaction sequences. The current study examines six hydrogen extractions, via the hydrogen or methyl radicals from the n-propyl side chain. Potential energy surfaces were determined using 10 different approaches, including state-of-the-art DFT (M06, M06-2X and M08-SO) and contemporary composite methods (G4, G4MP2, CBS-QB3 and CBS-4M). Results are presented relative to data obtained using the CCSD(T)/jun-cc-pVTZ//M06-2X/6-311++G(3df,3pd) coupled cluster based method. Rate parameters were determined using transition state theory combined with (i) small curvature tunnelling and energetics at the M06-2X/6-31G(2df,p) level and (ii) Eckart tunnelling corrections and energetics at the CCSD(T)/jun-cc-pVTZ level. Results were found to agree comparatively well with modest differences in rates for several reactions. However, it is also shown that substantial deviations can arise with respect to reaction class based estimation techniques.     

The Influence of the Magnitude of Gravitational Acceleration on Marangoni Convection About an Isolated Bubble under a Heated Wall

Thermocapillary or Marangoni convection is the liquid motion caused by surface tension variation in the presence of a temperature gradient along a gas–liquid or vapor–liquid interface. This work numerically investigates the effect of the magnitude of gravitational acceleration on the flow and temperature fields resulting from the presence of a hemispherical air bubble of constant radius of 1.0 mm, situated on a heated wall immersed in a liquid silicone oil layer of constant depth of 5.0 mm. The model is oriented such that the Marangoni and gravitational forces act to oppose one another. To elucidate the effect of gravity on Marangoni flow and heat transfer, the simulations were carried out for a silicone oil of Prandtl number 83, at a Marangoni number of 915. The gravity levels tested were 0g, 0.01g, 0.1g, 0.25g, 0.5g, 0.75g, and 1g, where g represents the earth gravitational acceleration of 9.81 m/s ² . The influence of the magnitude of gravitational acceleration on the velocity profile along the bubble interface and on the location of maximum velocity was analyzed. It was found that the gravity level affects the velocity profile by influencing the interfacial temperature gradient, but that the location of maximum velocity was almost independent of gravity level. The increase in heat flux on the wall to which the bubble is attached was calculated and it has been determined that local heat transfer enhancement of up to nearly 1.7 times that of the conduction only case can be achieved for the parameter range tested. Furthermore, local enhancement was observed to occur up to a distance of seven bubble radii for the zero-gravity case, but increased gravity levels cause a reduction in the effective radius of enhancement. The influence of the Marangoni flow on the heat transfer for the opposite cooled wall has also been analyzed.     

A Soybean Oil-Based Adhesive and Its Application for Birdseed Binding

Current birdseed binders are mainly based on animal protein and fat. However, exporting the seed cakes containing animal products to European countries can be difficult due to their import policies. A plant oil-based adhesive may be capable of binding loose seeds together, enabling it to be used as an alternative to the animal protein-based and fat-based binders used currently and making the exportation possible. A soybean oil-based adhesive was, therefore, synthesized and tested for birdseed binding in this study. The effects of the quantity of saturated fatty acylglycerols (i.e., fully hydrogenated soybean oil, FHSO) introduced into epoxidized soybean oil (ESO) and a phosphoric acid (H₃PO₄) cross-linker on product characteristics were investigated. Increased quantity of FHSO improved the glass transition point (T _g), hardness, and adhesion while further increasing the quantity led to various degrees of phase separation of the product. Increased quantity of H₃PO₄ also improved hardness and adhesion of the binder. A binder-MDAG (a mixture of mono and diacylglycerols at about a 1:1 ratio as a hardening agent) mixture (BMD) having an average hardness and adhesion of 4024 and 1197 g, respectively, was selected for seed binding. Seed cakes bound with 15 wt.% BMD were about twice as hard as gelatin-bound ones. Storage of the BMD itself in open air led to increased hardness, adhesion, and melting point, and storage of the seed cakes bound by BMD in open air led to increased hardness and high temperature tolerance. Seed cakes bound with BMD also presented much better water resistance.     

An efficient bicomponent TiO2/SnO2 nanofiber photocatalyst fabricated by electrospinning with a side-by-side dual spinneret method

In this communication, we demonstrate that the electrospinning process with a side-by-side dual spinneret can be a simple approach for fabricating bicomponent TiO2/SnO2 nanofibers with controllable heterojunctions. Specifically, both of the TiO2 and SnO2 components in the nanofibers are fully exposed to the surface. This morphology fully utilized the photogenerated holes and electrons during the photocatalytic process, thus leading to a high photocatalytic activity. We believe that this versatile approach can be extended to fabricate other novel high-efficiency bicomponent photocatalysts.     

High power AlGaAs-GaAs visible diode lasers

A high-power room-temperature AlGaAs graded index separately confined heterostructure (GRINSCH) laser emitting in the visible spectral regime (≃715 nm) is reported for the first time. The device is gain-guided and consists of 12 stripes, each 5 μm in width with a centerline separation of 9 μm. This high-power visible laser has been successfully fabricated using a GaAlAs active layer. The epitaxial layer was grown with significantly lower levels of oxygen compared to those grown using standard metalorganic sources. Threshold currents of 310 mA at 10°C were routinely measured on uncoated devices. The uncoated device had a catastrophic optical damage limit of 540 mW and has a slope efficiency as high as 0.48. No degradation in device performance was observed during a 50-hour 150-mW burn-in