Surface functionalization of mesoporous antimony doped tin oxide by metalorganic reaction

Electrically conducting mesoporous antimony doped tin oxide was functionalized by the metalorganic reaction with several Grignard reagents. This fast and efficient grafting approach enables a direct connection of the metal atoms with the organic functionalities avoiding the formation of insulating Si–O linkers, which is of special interest for the interfacial charge transfer processes. Using this approach we introduced vinyl, allyl and phenyl groups into the pores of mesoporous ATO, which was confirmed by IR spectroscopy, TGA and nitrogen sorption measurements. We obtained a high loading of organic groups corresponding to about 50–60% of the monolayer surface coverage. The obtained mesoporous inorganic–organic hybrids can serve as a platform for incorporation of electrochemically active species.     

Flow patterns and velocity fields in two-dimensional thin slice panel with flow-corrective insert

An experimental two-dimensional (2-D) thin slice panel for studying flow patterns of fine silica sand was designed and manufactured. As supplier of sand was not known at that time, flow properties of the silica sand were assessed without shear tests. A preliminary design of plane-flow hopper of the experimental 2-D panel was assumed to be close to the mass flow conditions. Sand was circulated in the experimental panel to study the steady state flow. Tests of flow patterns suggested typical funnel-flow patterns with stagnant zones in the hopper and in the vertical part of the panel. Stagnant zones near the bottom of the hopper indicated insufficient width of the hopper outlet. Shear tests for estimation of flow properties of silica sand were carried out additionally and two methods of how to transform the funnel flow of sand to the mass flow were followed up; (a) existing 2-D panel was retrofitted with flow-corrective element, and (b) the width of outlet in existing experimental panel was widen into the size, calculated according to mass flow conditions. Both modifications were proven to be successful and the last-in first-out funnel flow was transformed into first-in first-out mass flow of sand. Velocities of individual tracer particles were measured during mass flow and velocity field was evaluated. Velocity profile of particles in the vicinity of flow-corrective insert was studied in detail.     

Modelling and simulation of heat transfer by convection in aerogel treated nonwovens

Simulation and numerical modeling are becoming increasingly popular due to the ability to seek solutions for a problem without undertaking real-life experiments. For the problems of heat transfer, these techniques to generate relevant data by incorporating different changes to the input parameters. Heat transfer property of textile materials is a major concern since it influences comfort properties of clothing. In this paper, numerical simulation was applied to evaluate the heat flux, temperature distributions, and convective heat transfer coefficients of the fibrous insulating materials treated with aerogel. The computational model simulated the insulation behavior of nonwoven fabrics without and with aerogel. Ansys and Comsol were used to model and simulate heat transfer. The simulation was performed assuming laminar flow and since the Mach number was < 0.3, the compressible flow model with Mach number < 0.3 was used. The results of simulation were correlated to experimental measurements for validation. Furthermore, aerogel-treated fabric samples showed better thermal performance. Using this model, the heat transfer properties of the nonwoven fabrics treated with aerogel can be optimized further.     

Editorial

This editorial provides an overview of a special issue dedicated to the 7th conference on Process Integration, Modeling and Optimization for Energy Saving and Pollution Reduction—PRES 2004. Eight papers have been selected and peer-reviewed covering various subjects of heat transfer engineering, focusing on the recent development of various features of heat transfer equipment design and optimization. This is the fourth special issue of Heat Transfer Engineering dedicated to selected contributions from PRES conferences [1 Kleme?, J. and Stehlík, P. Heat Transfer Engineering. PRES Conference—Challenges in Complex Process Heat Transfer. vol. 23, pp.1–2. no. 6 [Google Scholar], 2 Stehlík, P. and Kleme?, J. Heat Transfer Engineering. Selected Papers from the PRES 2002 Conference. vol. 25, pp.1–3. no. 5 [Google Scholar], 3 Kleme?, J. and Stehlík, P. Heat Transfer Engineering. Selected Papers from the PRES 2003 Conference. vol. 26, pp.1–3. no. 5 [Google Scholar]].     

Relationship between chemical and rheological properties of two asphalts of different origins

The chemical and rheological properties of two asphalts selected from different sources (Urals, Russia; Cold Lake, Canada) were investigated. Analyses of chemical (elemental composition, fractional composition, molecular weights) and physical properties (complex viscosity, loss tangent, shear compliance) were performed on all original and aged (rolling thin film oven test, RTFOT; pressurized aging vessel, PAV) samples. The analyses of the chemical properties of both asphalts revealed higher asphaltene content, higher heteroatom content, and lower aging susceptibility of the Cold Lake asphalt (less significant changes in group composition). Based on its chemical composition, the Cold Lake asphalt was expected to perform better in the rheological tests than the Urals asphalt. The rheological tests confirmed this hypothesis and revealed better low- and high-temperature properties of the Cold Lake asphalt and a slower deterioration of its physical properties upon oxidative aging.     

Recalibration of the Large Scale Gap‐Test to a Stress Scale

A series of gap‐test experiments were conducted in accordance with the EMTAP Test 22a guidelines to characterize the stress output from a donor charge of ROWANEX 3601. Forty eight successful gap‐tests were conducted at the University of Pardubice in addition to two supporting plate impact experiments performed at the Cavendish Laboratory, University of Cambridge. The experiments indicated that there are two principal release mechanisms, which produce the observed reduction in stress with increasing gap distance. The first is attenuation of the input wave, something which is expected during explosive loading due to the triangular nature of the loading pulse. The second is an interaction between the input wave and lateral release waves from the edges of the test sample at the measurement station. Attenuation of the input wave due to visco‐elastic loss in the PMMA “gap” used is likely to be less significant than these other two release mechanisms. The data generated by this investigation forms a robust dataset that gives an accurate calibration for ROWANEX 3601 for users of the EMTAP 22a test procedure. In addition the data represent an excellent “set problem” for those developing and wishing to validate, computational models of similar physical phenomena.     

Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing

The microstructure and fracture properties of the Eurofer97 steel plates of thickness 14 mm and 25 mm were investigated in as-received state and in state after long-term thermal ageing (550 °C/5000 h). Detailed microstructure studies were carried out by means of optical light, electron and quantitative electron microscopy. Mechanical properties were evaluated by means of Charpy impact testing and hardness testing and fracture surfaces were fractographically analysed in macro and microscales. The microstructure of the Eurofer97 consisted of tempered martensite with M₂₃C₆ and MX precipitates. Microstructure of 14 mm plate was more homogenous and fine grained than 25 mm plate. Due to different microstructure the t_DBTT of thicker plate was on +10 °C higher than for 14 mm plate for which reached −60 °C. Slight microstructural changes on the level of subgrain consisting of their partial recrystallization and slight carbide coarsening were observed after applied ageing. The isothermal ageing caused evident shift in t_DBTT about +5 °C, which was most likely caused by recrystallization of subgrains.     

Wall pressure issues in the aeration of bulk material silos

Operators of bulk material silos frequently face various flow defects. These include defects in flow continuity, vaults, stick rings, and dead zones in the bulk material. The application of aeration systems in bulk material silos is an effective method used in order to eliminate the above defects. This paper presents a study of the effect of an aeration system on wall pressures σ_W of bulk material in a silo during a targeted bulk material aeration and relaxation process, and analyses the results in light of the calculation standards for designing bulk material silos, namely ?SN 73 5570 a DIN 1055.     

The Scent of a Partner: Ambrosia Beetles Are Attracted to Volatiles from Their Fungal Symbionts

Invasive fungus-growing ambrosia beetles are an emerging threat to forest ecosystems and fruit industries, but management tools are lacking. Here we explored the potential of beetle symbionts–ambrosia fungi–as a source of attractants. Our focus was the redbay ambrosia beetle, Xyleborus glabratus, and its symbiotic fungus, Raffaelea lauricola, which are devastating lauraceous hosts in the southeastern United States. We also tested three additional co-occurring beetle species and their symbionts. Each beetle species was consistently attracted to the odors of its symbiotic fungal species, occasionally also to symbionts of other species, but never to non-symbiotic Trichoderma. We further confirmed attraction to ethanol (positive control) in some species. Thus, ambrosia fungi produce volatiles attractive to their vector beetles, which may have potential as novel lures for ambrosia beetle management.