Weathering,water absorption,and durability of silicon,acetylated, and heat‐treated wood

In this study, two colloidal dispersions of pure amorphous silicon dioxide particles, acetylated, and heat‐treated samples were tested for a possible application as a wood protection agents. The silicon, acetylated, and heat‐treated samples were exposed to an accelerated weathering experiment, and their dimensional stability was assessed. The weathering experiment comprised cycles of 2 h UV‐light irradiation followed by water spray for 18 min. The surface changes of the weathered samples were characterized by FT‐IR spectroscopy and color measurements. According to results, the silicon treatments showed lower color changes than untreated ones. However, acetylated and heat‐treated samples provided the lowest color changes. The resistance of the silicon, acetylated, and heat‐treated wood to decay was studied by means of brown and white rot fungi in laboratory decay tests. Decay test results revealed that acetylated and heat‐treated wood samples showed better decay resistance against P. placenta and C. versicolor than silicon treatments. Samples modified with silicon were exposed in above ground standard lap‐joint test in Ultuna, Sweden. The dispersions of pure amorphous silicon dioxide impregnated in wood did not significantly influence its hygroscopic and dimensional behavior. However, the silicon treatment reduced the color changes caused by weathering. The silicon impregnated samples showed a weak fungal discoloration similar to that of chromated copper arsenate impregnated controls in above ground standard lap‐joint test. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4506–4513, 2006     

Gravity drainage of activated sludge: new experimental method and considerations of settling velocity, specific cake resistance and cake compressibility

A laboratory scale setup was used for characterization of gravitational drainage of waste activated sludge. The aim of the study was to assess how time of drainage and cake dry matter depended on volumetric load, SS content and sludge floc properties. It was demonstrated that activated sludge forms compressible cakes, even at the low pressures found in gravitational drainage. The values of specific cake resistance were two to three orders of magnitude lower than those obtained in pressure filtration. Despite the compressible nature of sludge, key macroscopic parameters such as time of drainage and cake solid content showed simple functional dependency of the volumetric load and SS of a given sludge. This suggests that the proposed method may be applied for design purposes without the use of extensive numerical modeling. The possibilities for application of this new technique are, among others, the estimation of sludge drainability prior to mechanical dewatering on a belt filter, or the application of surplus sludge on reed beds, as well as adjustments of sludge loading, concentration or sludge pre-treatment in order to optimize the drainage process.     

Magnetic properties of Ni-Co thick-film magnetoresistors

Magnetic susceptibility from 300 to 900 K, room temperature hysteresis cycles and saturation magnetization were investigated in screen printed and fired NiCo-based layers prepared at various peak temperatures. A bulk NiCo metal sheet of comparable composition was also studied. Values of the magnetic polarization J of 0.28 and 0.435 T were obtained (at 200 kA/m) for films prepared at 750 and 950°C, respectively, in contrast with J=0.98 T for the bulk alloy. In addition, the magnetoresistive responses of the layers and the sheet were plotted. These data suggest that strains, pores and lack of composition homogeneity in the films concur in affecting their magnetic properties, and are responsible for their reduced magnetoresistance anisotropy (e.g. ca. 4% for films as compared to ca. 8% for the bulk alloy at H=80 kA/m).     

Transition to chaos in Rayleigh-Bénard convection

The Boussinesq equations for the Rayleigh-Bénard problem have been solved by analytical and numerical methods. Two different sequences of Hopf bifurcations, leading from, stationary two-dimensional rolls to non-periodic motion, have been identified. For one of the sequences the first bifurcation results in transverse oscillations of the rolls. The next bifurcation gives quasiperiodic flow, and the sequence ends in chaotic motion after the third instability. The second route is characterized by waves in the periodic regime, travelling along the rolls. Thereafter two quasiperiodic regimes follow with two and three frequencies, respectively. Both types of sequences have been detected in the experiments reported by Gollub and Benson (1980). The regime of travelling waves is also analysed by a perturbation method.     

Magnetoresistive properties of Ni-based thick films

Investigations have been carried out on the electrical properties of nickel-based films prepared from air-fireable pastes on alumina substrates. In particular, magnetoresistive effects have been studied as a function of temperature, strength and direction of the magnetic field. These properties were determined in films at different stages of formation, i.e. prepared at various peak firing temperatures and dwell times, and compared with those displayed by nickel foils. These results provide the basis for the development of magnetoresistive thick-film sensors.     

Effects of visual alcohol cues on alcoholics' autonomic arousal.

Determined whether visual alcohol cues alone (slides showing drinking environments and alcohol beverage bottles) were sufficient to elicit autonomic arousal. 82 male alcoholics (aged 25–64 yrs) were shown alcohol-related or control slides while electrodermal responses were being recorded. Each slide was presented for 4 sec and interstimulus intervals varied between 20 and 30 sec. The frequency of skin conductance responses (SCRs) and the amplitude of the first SCR to each picture presentation were greater to alcohol slides than to control slides. The Ss showed slower habituation to alcohol-related slides as compared with control slides. Pictures of hard liquor yielded higher SCR amplitudes than did pictures of beer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preparation and operation of gas diffusion electrodes for high-temperature proton exchange membrane fuel cells

Gas diffusion electrodes for high-temperature PEMFC based on acid-doped polybenzimidazole membranes were prepared by a tape-casting method. The overall porosity of the electrodes was tailored in a range from 38% to 59% by introducing porogens into the supporting and/or catalyst layers. The investigated porogens include volatile ammonium oxalate, carbonate and acetate and acid-soluble zinc oxide, among which are ammonium oxalate and ZnO more effective in improving the overall electrode porosity. Effects of the electrode porosity on the fuel cell performance were investigated in terms of the cathodic limiting current density and minimum air stoichiometry, anodic limiting current and hydrogen utilization, as well as operations under different pressures and temperatures.     

FSAP Protects against Histone-Mediated Increase in Endothelial Permeability In Vitro

Factor-VII-activating protease (FSAP) is involved in the regulation of hemostasis and inflammation. Extracellular histones play a role in inflammation and the conversion of latent pro-FSAP into active FSAP. FSAP has been shown to regulate endothelial permeability, but the mechanisms are not clear. Here, we have investigated the effects of FSAP on endothelial permeability in vitro. A mixture of histones from calf thymus stimulated permeability, and the wild-type (WT) serine protease domain (SPD) of FSAP blocked this effect. WT–SPD–FSAP did not influence permeability on its own, nor that stimulated by thrombin or vascular endothelial growth factor (VEGF)-A₁₆₅. Histones induced a large-scale rearrangement of the junction proteins VE-cadherin and zona occludens-1 from a clear junctional distribution to a diffuse pattern. The presence of WT–SPD–FSAP inhibited these changes. Permeability changes by histones were blocked by both TLR-2 and TLR4 blocking antibodies. Histones upregulated the expression of TLR-2, but not TLR-4, in HUVEC cells, and WT–SPD–FSAP abolished the upregulation of TLR-2 expression. An inactive variant, Marburg I (MI)–SPD–FSAP, did not have any of these effects. The inhibition of histone-mediated permeability may be an important function of FSAP with relevance to sepsis, trauma, and stroke and the need to be investigated further in in vivo experiments.