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Portuguese 2004 [1 p.] Brazil Souza Filho, Paulo Artur Coelho de

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The Netherlands Energy Research Foundation investigated the acidification of fog and dew. Both have little effect on the total acid deposition, but they contribute strongly to the hazardous effects on plants. In particular the effects of hydrogen peroxide and sulfite in fog and dew on plants have been investigated. Special attention is paid to the development of the measurement and sampling equipment. Results of the measurements are presented. 9 figs., 4 refs., 1 tab.

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This paper describes the experimental results of accelerated aging tests conducted on three different types of polymer materials. Salt fog chamber tests were used to study the surface degradation modes for all materials. The work presented here was performed using a newly constructed fog chamber system that was able to control both chamber humidity and UV radiation. The changes in the surface morphology, material structure and leakage current were examined to study the influence of environmental humidity.

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Corrosion characteristics of Al and Cu thin films have been studied in cyclic fog tests using tap water fog and fog created with 0.1% NaCl solution in tap water. Likewise, their corrosion features have been analyzed in continuous immersion testing in the laboratory in distilled water, tap water, in 0.1% NaCl and 3.5% NaCl solutions in distilled water. The corrosion potentials and the corrosion currents of these thin films change and reach steady state values after some time. However, steady state is not realized in 3.5% NaCl solutions. The corrosion current density data have been used to calculate lifetime of 1 {mu}m thick thin films of Al and Cu in the various tests, and assuming that the fog test data would hold under normal exposure conditions, life spans for these thin film sensor elements in actual exterior exposure have also been calculated. According to estimates, an Al-TF of about 1 {mu}m would ...

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Recent work has shown that natural hydrocarbon emissions can significantly affect the levels of urban and regional tropospheric ozone. We report on the reactivities of these biogenic trace gases, particularly isoprene, focusing on their importance in the production of aldehydes and peroxy radicals, leading to increased levels of hydrogen over regional forests. Hydrogen peroxide can lead to the wet oxidation of sulfur dioxide to acidic sulfate in aerosols, fogs, and clouds. In turn, acidic sulfate can act to as a light scattering aerosol and a source of cloud condensation nuclei (CCN), potentially leading to global cooling. Aerosol sulfate and other dissolved organic and inorganic compounds can also play important roles as a greenhouse species in the lower troposphere.

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We have investigated the effect of plasma nitriding and plasma nitrocarburizing on the microstructure and properties of electroplated chromium. Plasma nitriding and plasma nitrocarburizing are applied to 15-100 [mu]m thick electroplated hard chromium coatings to increase both the wear and the corrosion resistance. The properties of the plasma-modified hard chromium layers are characterized by measuring the wear resistance with a Taber wear tester and the corrosion resistance with a salt spray fog test. Cyclic voltammetry is performed in a standard electrochemical cell using a 0.5 M H[sub 2]SO[sub 4] solution acidified to pH 0.3. The compound layer after plasma nitriding consists of CrN and Cr[sub 2]N with a maximum hardness of about 1100 HK[sub 0.01]. After plasma nitrocarburizing, Cr[sub 3]C[sub 2] and Cr[sub 7]C[sub 3] are formed. After plasma nitrocarburizing, the maximum hardness is increased up to 2200 HK[sub 0.01]. The wear rate is reduced as compared to an ...

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The purpose of this study was to correlate MR imaging findings with pathology in experimental hyperoxia-induced acute lung injury, which has similar pathology to diffuse alveolar damage (DAD). Seventeen Yorkshire pigs were studied. These animals were exposed to more than 80% oxygen for 24, 48, 72, and 96 hours in a sealed cage. The lungs were removed and inflated with air infused through the trachea, and then examined by both MRI and high-resolution CT (HRCT). T1-weighted spin-echo (T1WSE), T2-weighted fast (T2WFSE), and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences were performed. Severity in MR findings and signal-to-noise ratios (SNR) on MR images were well correlated with pathological scores. CT values were also correlated well with pathologic scores. Abnormal SNR values were obtained from a pathological score of 5, whereas abnormal CT values were obtained from a pathological score of 15. Furthermore, significant differences in SNR were ...

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Quantitative bone scans were evaluated in 16 patients with osteoporosis and in a control group of 7 healthy subjects. Along with a detailed biochemical analysis of calcium-phosphorus metabolism and standartized reongenographs, a quantitative dynamic bone scintigraphy was performed according to the method proposed by the authors. The bone-accumulating factor K_b was determined on the base of mathematical analysis of the graph reflecting activity changes in bone tissue unit during the investigation, the blood-elimination factor K_h and kidney-elimination factor K_k. In addition the accumulation index AI (in %) was calculated as a relation between the activity in bone tissue unit, registered in 20 min interval, and the activity in soft tissues for the same time. Whereas the static gamma camera scintigraphy, made 3-4 hrs after injecting of the osteotrope radiopharmaceuticals, showed no specific changes in the patients examined, the method proposed realised higher K_b and considerably ...

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45{number_sign} steel, which has good mechanical strength and is relatively cheap, is a common constituent in industrial components, such as precision gears, piston columns of oil pumps, and so on. However, since the working environment of these industrial parts is sometimes quite harsh and unforgiving, they are vulnerable to wear and corrosion. Replacing 45{number_sign} steel with stainless or alloy steel increases the cost significant, and a better alternative is to improve its surface properties and lifetime using plasma immersion ion implantation (PIII). The authors have devised a variety of treatment processes using PIII, including radio-frequency (RF) plasma nitriding, RF plasma nitriding and nitrogen PIII, Ti deposition in conjunction with nitrogen PIII (IBED), as well as Cr deposition followed by nitrogen PIII (IBED). To assess the efficacy of the processes, the microhardness and mass loss due to wear were measured for both the untreated and treated 45{number_sign} samples. A ...

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Dams and reservoirs are among one of the most sensitive of all development Project, in terms of pervasiveness of their influence in altering the environmental conditions and resources. In the present study, major dams and reservoir projects are reviewed, from the environmental point of view. Dams and Reservoir projects bring about major changes in the immediate environment, thus affecting public health, settlements, farmlands, roads and historical sites. Impacts on human population and wildlife may be profound. Tropical diseases, involving fresh-water hosts or vectors in their transmission, are often common around new reservoirs. Large lakes create limnological changes, excessive evaporation, seepage, disturbance in water-table and increased tendencies of landslides and earthquakes. Micro climatic changes are possible, such as fog formation, increased cloudiness and modified rainfall-patterns. Retention of sediment results in silting up of reservoirs. Water ...