Fire resistance of wood treated with a cationic silica sol

Wood was treated with the cationic silica sol (CSS) Levasil 200S and dried at various temperatures (room temperature, 40, 60, 80 and 103 °C). A water leaching test revealed fixation of the silica in wood even after drying at room temperature. Maximum cross sectional swelling of the specimens decreased from 15.6 % (untreated control) to 13.0 %, when treated wood was dried at 103 °C; cell wall bulking values were also negative (?2.3 %), indicating a thermal degradation of the cell wall polymers catalyzed by the CSS. Penetration of the CSS into the cell wall did not occur. A simple flammability test revealed increased fire resistance of the treated wood. Mass loss and velocity of mass loss as well as burning time were reduced; glowing of the formed charcoal was completely prevented. The effectiveness increased with increasing weight percent gain of the CSS in the wood. Thermo gravimetric analysis under nitrogen atmosphere displayed only minor reduction in the initial temperature of thermal decomposition for wood treated with CSS as compared to the control. In the presence of oxygen the resulting charcoal showed comparable thermal behaviour to the control. The yield of charcoal after pyrolysis was increased to a minor extent (from 19.9 to 23.0 %), indicating that the release of combustible gases was hardly reduced. The mode of action of enhanced fire resistance due to CSS-treatment is discussed.     

微星X-Slim X340笔记本新“刀锋战士”

2009年1月召开的CES2009展上，微星（MSI）展出了令人惊艳的X—Slim系列笔记本产品。引起了业内的广泛关注。但是在接下来的两个月时间里。微星却一直对其遮遮掩掩，吊足了笔记本爱好者的胃口。，     

Bioremediation of soil contaminated with alkyllead compounds

Sandy soil, which was highly contaminated with alkyllead compounds, was taken from bore cores from a site of a former tetraalkyllead producing company. It was analyzed for its capacity to chemically and/or biologically degrade alkyllead contaminants. For this purpose, soil samples were supplied with oxygen or oxygen + minerals at different water saturation. For long-term elution, contaminated soil was packed into glass columns of 1.5m length and 10cm diameter. Oxygen-saturated water was recirculated in an upflow mode. Within a time span of 260 days tetraethyllead was completely eluted from the sandy soil and was apparently converted to triethyllead by chemical or microbiological reaction. The triethyllead concentration in the circulating water accounted for 60-80% of the maximal amount, that could be formed from tetraethyllead by a single dealkylation. This indicated that between 20-40% of the triethyllead were apparently further degraded. Only very little diethyllead accumulated in the water. The triethyllead concentration in the circulating water was highly toxic for non-adapted microorganisms. However, if a readily degradable carbon source was added, fast growth of indigenous soil bacteria was observed, but only little alkyllead degradation occurred.     

Auto-ignition hazard of mixtures of ammonia,hydrogen, methane and air in a urea plant

The auto-ignition of NH(3)/CH(4)/H(2)/air mixtures constitutes a hazard that is of much concern in urea plants. In this study, the auto-ignition behaviour of NH(3)/CH(4)/H(2)/air mixtures is investigated experimentally for pressures up to 7500 kPa. The experiments were carried out in a closed spherical vessel with a volume of 8 dm(3). The concentration and the pressure dependence of the auto-ignition temperature (AIT) were determined for four types of mixtures: NH(3)/air, NH(3)/CH(4)/air, NH(3)/H(2)/air and NH(3)/CH(4)/H(2)/air. The most ignitable NH(3)/air mixtures were situated between stoichiometry and the upper flammability limit. Small amounts of methane and hydrogen decrease the AIT of NH(3)/air mixtures to a large extent. The pressure dependence of the AIT could be correlated by a Semenov relationship. For the multi-fuel mixtures, a distinct deviation from the Semenov correlation was observed at the lowest temperatures. With respect to the explosion hazard in urea plants, the experimental results were used to assess realistic AIT values in the pool reactor and the ammonia scrubber, operating at a pressure of 15,000 kPa.     

Practitioner development: From trained technicians to reflective practitioners

The EPSRC funded Rethinking Project Management Network produced several insights into new directions for project management theory and practise, highlighting gaps between current theory and practise in several areas. This paper reviews the discussions around project management practitioner development that arose out of this rethinking process where project management is seen as growing from a predominantly technical skill-set to a broader practise of reflectively managing the things needed to provide a successful project outcome. In particular, the paper identifies and addresses the challenges of developing competent project managers in a world exhibiting increasingly complex project challenges, and when skilled resources at all levels are often increasingly scarce. We provide examples of practical and academic initiatives that are designed to address these challenges: internal assessment and development programs, reflective practice thesis, and distance-based critical management MBA. We conclude by speculating on some of the further challenges in developing reflective practitioners that have yet to be resolved.     

Comparison of the pharmacological profile of S-nitrosothiols, nitric oxide and the nitrergic neurotransmitter in the canine ileocolonic junction

1. In organ bath experiments, hydroquinone (30-100 microM) and hydroxocobalamin (30-100 microM) concentration-dependently inhibited the relaxations induced by NO (0.3-30 microM) but not those by nitroglycerin (GTN, 1 microM) in the canine ileocolonic junction (ICJ). Hydroxocobalamin reduced the relaxation to low frequency (2 Hz) stimulation of the non-adrenergic, non-cholinergic (NANC) nerves, whereas hydroquinone only reduced the NANC nerve-mediated relaxations to electrical stimulation at 16 Hz, 0.5 ms. 2. Relaxations to S-nitroso-L-cysteine (CysNO, 1-30 microM), or S-nitroso-N-acetyl-D,L-penicillamine (SNAP, 1-30 microM) were not inhibited by hydroquinone (30-100 microM), hydroxocobalamin (30-100 microM), pyrogallol (30-100 microM) or L-cysteine (1-3 microM). Hydroquinone (100 microM) only reduced the relaxation to 10 microM CysNO. Hydroxocobalamin, but not hydroquinone, pyrogallol or L-cysteine, potentiated the relaxations to the lowest concentration (1 microM) of S-nitrosoglutathione (GSNO, 1-30 microM). 3. In the superfusion bioassay, hydroquinone (100 microM) and hydroxocobalamin (1 microM) concentration-dependently inhibited the biological activity of authentic NO (1-4 pmol) to the same extent as that of the transferable nitrergic factor, released from the canine ICJ in response to NANC nerve stimulation (8-16 Hz, 2 ms). Responses to GTN (10 pmol) or adenosine 5'-triphosphate (10 nmol) were not affected. 4. In conclusion, the nitrosothiols CysNO, SNAP and GSNO relax the canine ileocolonic junction, but these relaxations, pharmacologically, behave differently from the NANC nerve-mediated relaxations. From the bioassay experiments, we conclude that the nitrergic factor, released in response to NANCnerve stimulation of the canine ICJ, behaves pharmacologically like NO but not like a nitrosothiol.Therefore, we suggest NO, and not CysNO, SNAP or GSNO as the inhibitory NANC neurotransmitter in the canine ICJ.     

Changes in fetal plasma corticotropin-releasing hormone during androstenedione-induced labor in the rhesus monkey: lack of an effect on the fetal hypothalamo-pituitary-adrenal axis

Androstenedione infusion to pregnant monkeys leads to premature labor and live delivery. Androstenedione-induced labor also increased placental CRH messenger RNA and peptide to concentrations observed at term in pregnant monkeys. Placental CRH may modulate fetal pituitary-adrenal function during pregnancy in primates. This study tested the hypothesis that androstenedione-induced premature delivery in pregnant monkeys results from androstenedione-induced increases in placental CRH, which stimulate premature activation of the fetal pituitary-adrenal axis. The hypothesis was tested by comparing fetal umbilical vein (FUV) plasma CRH, ACTH, dehydroepiandrosterone sulfate, and cortisol concentrations at cesarean section in fetuses from mothers undergoing spontaneous, term labor (group I), with those in fetuses from mothers undergoing androstenedione-induced, premature labor (group II) and with those from mothers not in labor (group III). In addition, gestation-related changes in maternal plasma CRH concentrations were investigated, and CRH immunoactivity was characterized by Sephadex G50 chromatography in pooled maternal plasma extracts. FUV CRH concentrations were similarly elevated in group I and group II fetuses, compared with group III fetuses. Despite similar FUV blood gases in all fetuses, FUV ACTH and dehydroepiandrosterone sulfate concentrations were higher in group I fetuses than in group II or group III fetuses. The majority of CRH immunoactivity coeluted with synthetic human CRH. Maternal plasma CRH concentrations showed a modest increase with gestation in the rhesus monkey. These data: 1) demonstrate that androstenedione treatment of pregnant monkeys at 0.8 of gestation elevates fetal plasma CRH to similar concentrations measured at term; 2) do not support the hypothesis that androstenedione-induced delivery in the monkey results from premature activation of the fetal pituitary-adrenal axis by placental CRH; but 3) do support a role for activation of the fetal hypothalamo-pituitary-adrenal axis in association with spontaneous term labor in the monkey; and 4) demonstrate important interprimate species differences in maternal CRH physiology.     

Investigation of the energy flows for transparent and nontransparent building facade

Based on extensive measurements of energy usage for a variety of building facades, a computer model has been developed for calculating in advance the heating and cooling requirements of test rooms equipped with arbitrary facades. To simplify the predictive calculation, the three-dimensional physical model was transformed to a one-dimensional, linear, computational model. The computer model uses the results of an earlier sensitivity analysis. This permits the precise numerical modeling of the measured results and gives special value to the adaptation of this model for describing the geometric and thermal relations investigated experimentally. The results of the numerical calculations are found to be in good agreement with the measurements for six test rooms. This agreement justifies the linear numerical model and the computer program for predicting the energy flows in different room structures. Further, the computer model not only provides results which follow the course of weather conditions for the test year but yields results as well for a Standard Reference Year for the region.