Rain Test Research Articles

Proporção e tamanho de sedimentos e teor de carbono orgânico na enxurrada e no solo para dois cultivos e duas formas de semeadura

O tipo de cultura e a orientação de semeadura em relação ao declive do terreno podem modificar a proporção e o tamanho dos sedimentos transportados na enxurrada, além da relação do teor de C orgânico nos sedimentos e no solo erodido. Este trabalho teve o objetivo de determinar a proporção e o tamanho dos sedimentos transportados pela enxurrada sob taxa constante desta e o teor de C orgânico contido nos sedimentos e no solo erodido, sob duas formas de semeadura das culturas de aveia e ervilhaca. Quatro testes de chuva simulada foram aplicados entre março e novembro de 2006, durante o ciclo vegetativo das culturas, com intensidade constante de 64 mm h-1 e 1 h de duração de cada teste, em Lages, SC, num Cambissolo Húmico com declividade média de 11,9 cm m-1. Os tratamentos eram formados pela combinação de duas culturas e duas orientações de semeadura em relação ao declive. As culturas utilizadas foram aveia (Avena strigosa) e ervilhaca (Vicia sativa); as formas de semeadura eram: mecanizada em linhas em contorno ao declive e mecanizada em linhas paralelas ao declive (morro abaixo). As amostras de enxurrada para a coleta dos sedimentos foram obtidas sob taxa constante de enxurrada, aos 50 min de duração de cada teste de chuva. A aveia reduziu a quantidade de sedimentos na enxurrada em 46 % em relação à ervilhaca, e a semeadura em contorno, em 56 % em relação à semeadura morro abaixo. A proporção de sedimentos na enxurrada foi diminuída em 63 % entre o início e o final do ciclo das culturas. Na classe de menor tamanho dos sedimentos (< 0,038 mm), a aveia aumentou sua proporção em 17 % em relação à ervilhaca, e o contorno os aumentou em 10 % em relação à semeadura morro abaixo. O índice D50 dos sedimentos presentes na enxurrada foi de 0,043 mm na aveia e 0,119 mm na ervilhaca, e de 0,047 mm na semeadura em contorno e 0,117 mm na semeadura morro abaixo. A razão entre o teor de C orgânico dos sedimentos transportados pela enxurrada e o teor de C do solo na camada de 0-2,5 cm foi de 1,39 na aveia e 1,21 na ervilhaca, e de 1,43 na semeadura em contorno e 1,17 na semeadura morro abaixo.

In-situ growth of silica nanoparticles on cellulose and application of hierarchical structure in biomimetic hydrophobicity

Monodispersed silica nanoparticles were prepared by a simple two-step method with hydrolysis and condensation. The materials were characterized by dynamic light scattering (DLS), SEM and TEM. Through in-situ growth of silica nanoparticles on cotton fabrics, a dual-scaled surface with nanoscaled roughness of silica and microscaled roughness of cellulose fiber was generated. After the modification of the low surface energy, the wettability of smooth silicon slide, silicon slide with nanoscaled roughness of silica particles, cotton fabric, and cotton fabric with silica particles was evaluated by the tests of the contact angle (CA) and the advancing and receding contact angle (ARCA). The cotton fabric with dual-scaled roughness exhibits a static CA of 149.8° for 4 μL water droplet and a hysteresis contact angle (HCA) of 1.8°. The results of CA and HCA show that microscaled roughness plays a more important role than nanoscaled roughness for the value of CA and HCA. The results in the hydrostatic pressure test and the rain test show the important contribution of nanoscaled roughness for hydrophobicity.

Measurement of the resistive leakage current in surge arresters under artificial rain test and impulse voltage subjection

Surge arresters are installed on transmission and distribution lines and in substations between phase and earth in order to improve the lightning performance and reduce the failure rates. High-energy stresses and housing deterioration are the main factors of degradation and damage of surge arresters. Thus, there is need for testing and monitoring the electrical network's arresters, in order to verify their good condition and their ability to effectively protect the lines. The most common method used, is the measurement of the arresters' total leakage current (with the isolation of the resistive part), which is an indicator of the arrester's condition, since every change, deterioration or damage leads to an increase of the resistive leakage current. In the current work, the total leakage current of two 20 kV ZnO surge arresters without gaps is measured and the resistive component for three different cases (brand new arresters, measurements under artificial rain and measurements after impulse voltage subjection) is computed. The analysis of the produced results can be useful in correct diagnosis of arresters' condition and in more effective schedule maintenance, since any recorded high-resistive currents do not necessarily result arrester's repair or replacement.

Rugosidade superficial do solo formada por escarificação e influenciada pela erosividade da chuva

A rugosidade superficial do solo é influenciada, entre outros fatores, pelo efeito residual de manejo do solo, pelo tipo de preparo e pela erosividade da chuva e, juntamente com a cobertura do solo por resíduos vegetais, influencia a erosão hídrica. O objetivo deste trabalho foi determinar, entre junho de 2005 e março de 2006, em um Nitossolo Háplico alumínico típico, o efeito de uma operação de escarificador e da erosividade de chuvas sobre a rugosidade superficial, nos seguintes sistemas de manejo do solo: preparo convencional sem cultivo do solo (SCE), preparo convencional com cultivo do solo (PCE), semeadura direta em solo nunca preparado e com resíduos queimados (SQE) e semeadura direta tradicional (STE). Nos tratamentos PCE, SQE e STE, cultivaram-se aveia-preta, soja, ervilhaca comum, milho, aveia-preta, feijão preto, nabo forrageiro, soja, ervilhaca comum, milho e aveia-preta. Aplicaram-se cinco testes de chuva simulada, com 64 mm h-1 e duração de 20, 30, 40, 50 e 60 min cada um. Entre o segundo e o terceiro teste de chuva simulada ocorreram 57 mm de chuva natural; entre o terceiro e o quarto, 21 mm; e entre o quarto e o quinto, 30 mm. Determinou-se a rugosidade superficial imediatamente antes e logo após o preparo do solo com escarificador e imediatamente após cada teste de chuva simulada. A rugosidade original e linear da superfície do solo não foi influenciada pelo manejo, enquanto a rugosidade ao acaso teve essa influência, ao final de um pousio de seis meses. Diferentes sistemas de manejo do solo mantidos em pousio por seis meses resultaram em diferente rugosidade original, linear e ao acaso, quando o solo foi submetido à operação de escarificador. A rugosidade ao acaso foi menos influenciada pela declividade do terreno do que pelas marcas de preparo do solo, tendo diminuído com o aumento da erosividade das chuvas. Essa mesma rugosidade apresentou coeficiente de decaimento temporal semelhante nos sistemas de manejo do solo semeadura direta e preparo convencional.

Image analysis of periodic rain accelerated corrosion of aeronautical aluminium alloys

Periodic rain tests have been carried out for simulating atmospheric corrosion of aeronautical aluminium alloys. A digital image preprocessing and analysis method based on wavelet transformation was used to study the corrosion morphology of aluminium alloys samples, through which an image feature parameter δ was extracted and discussed. The influences of orthogonal experiment parameters on acceleration were analyzed according to image feature parameter δ with analysis of variance (ANOVA) method, and the optimal parameters for accelerated corrosion test were also obtained. The result was shown to be consistent with that from weight loss method.

Covalent coating of coal refuse to inhibit leaching

Acid mine drainage (AMD) is a severe environmental problem that results from the oxidation of pyrite (FeS 2) and various other metal sulfides. AMD is often associated with abandoned mines which produce acidic run-off waters that are rich in heavy metals. AMD also occurs in the areas surrounding coal refuse piles that have accumulated from coal cleaning processes. In the present work, the use of the disodium salt of the ligand 1,3-benzenediamidoethanthiol (Na 2BDET) is explored as a possible coating to prevent the dissolution of pyrite in coal. Unlike phosphate- and silica-based compounds, Na 2BDET is believed to form covalent Fe–BDET linkages along the pyrite lattice. It was found that Fe leaching from BDET-coated coal is reduced by 99.3% when submerged in a pH 6.5 solution, by 97.5% when submerged in a pH 3.0 solution, and 66.4% when subjected to acidic and oxidative conditions. The ligand coating treatment also reduced the leaching of other heavy metals, such as Mn, Cu, Ni, Zn where a reduction of 88.3%, 64.7%, 70.5% and 89.5%, respectively, was observed in leaching after a 14-day simulated acid rain test. Additional leaching reductions were observed for metals such as Zn, Cu, Co, etc. at pH 6.5 and 3.0 when subjected to both oxidative and acidic conditions.

撥水性エポキシ樹脂の耐候性,耐トラッキング性の評価と劣化解析

The hydrophobic epoxy resin system for outdoor insulation was examined by various endurance tests, that is, high energy Xenon weathering test, ozone aging test, and acid rain test. After them, following properties were evaluated, e.g. surface micro-formation, surface roughness, contact angle, and tracking and erosion resistance. These surface properties of the hydrophobic and the conventional epoxy systems were not changed after the ozone aging test and the acid rain test. However after the Xenon weathering test, these properties were changed. The contact angle of conventional cycloaliphatic epoxy system was declined, but the contact angle of hydrophobic epoxy system was increased with progressing the test. From the IEC tracking test, is was confirmed that tracking and erosion resistance of the hydrophobic epoxy system was better than the conventional cycloaliphatic epoxy system. As the result of the degradation analysis, it was clarified that even though the base material is the same, hydrophobic epoxy system has much better weatherability.

The effect of substrate minor compositional differences on the corrosion performance of coated steels

Cabinet tests with wet and dry cycles were undertaken to investigate the effect of small differences in the composition of steels provided by two different manufacturers on their corrosion behaviour when coated and exposed to controlled atmospheres inside a cabinet. A clear alkyd lacquer was chosen as the coating in order to facilitate the monitoring of the corrosion features. Scribed panels were exposed to two aggressive atmospheres. The first environment simulated the effect of industrial atmospheres (Prohesion test). The second environment was made up of a solution which was 10 times more concentrated than the acidic rain of Manchester. In the Prohension test, the corrosion characteristics of the coated steels obtained from different manufacturers showed distinct differences which seemed to be related to the microstructural characteristics of the various steels, mainly their inclusion content. However, the results from the acid rain test did not distinguish the various coated specimens in terms of their corrosion behaviour. The Prohesion test was more corrosive than the acid rain test. This indicates that the degree of corrosivity of the environment influences the ranking of coated specimens in relation to their corrosion performance.

Rain and contamination tests on HVDC wall bushings with and without RTV coatings

Results of tests made to determine the ability of room temperature vulcanized (RTV) silicone rubber coatings to improve the performance of HVDC wall bushings are described. The behavior of uncoated full-scale +or-500 kV wall bushings is first determined in wetting conditions consisting of nonuniform rain and fog with various amounts of predeposited surface contamination. Parameters affecting flashover performance, such as polarity, rain conductivity, and contamination severity, are discussed. Results of nonuniform rain tests on an RTV coated wall bushing are reported. Fog tests and in-service experience have demonstrated that RTV coatings improve the HVDC contamination flashover performance of station post insulators; no flashovers occur in laboratory clean fog tests at rated voltage with ESDD levels up to 0.1 mg/cm/sup 2/. The application of RTV, silicone grease, or oily coatings makes the surface of a wall bushing sufficiently hydrophobic to prevent flashovers during nonuniform rain tests without a pre-deposited layer of contamination.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Field distribution on an HVDC wall bushing during laboratory rain tests

An efficient countermeasure to suppress flashovers across high-voltage DC (HVDC) wall bushings is to make their surfaces hydrophobic. The measured electric fields along such a bushing under different environmental conditions are reported. A significantly reduced radial field strength has been found for the hydrophobic bushing. Moreover, the total field strength distribution becomes almost independent of the prevailing dry zone. The flashover voltage for bushings with a hydrophobic surface is therefore significantly increased.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Laboratory tests to evaluate HVDC wall bushing performance in wet weather

Two test methods are developed to simulate the conditions causing flashover of DC wall bushings at working voltage. One is based on the clean-fog pollution test. The other is a rain test, with part of the bushing unwetted. The effect of varying test parameters is measured and five variants of rain test are adopted for measuring the performance of a wall bushing. Its performance compared unfavorably with that of an empty porcelain shell. Various numbers of booster sheds (removable silicone-rubber cones fitted round the bushing) are found to improve its performance substantially.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The American West's Acid Rain Test. Research report of the World Resources Institute, available by post from WRI Publications, P.O. Box 620, Holmes, Pennsylvania 19043, USA: v + 50 pp., 28.0 × 21.5 × 0.5 cm, figs &amp; tables, US $4.50 soft cover, 1985

The American West's Acid Rain Test. Research report of the World Resources Institute, available by post from WRI Publications, P.O. Box 620, Holmes, Pennsylvania 19043, USA: v + 50 pp., 28.0 × 21.5 × 0.5 cm, figs &amp; tables, US $4.50 soft cover, 1985 - Volume 13 Issue 4

Recording Effects of Rain Erosion with High Speed Photographic Techniques

Although controlled rain erosion testing is one of many types of captive dynamic testing that is carried out for missile and space vehicle systems at the Holloman High Speed Track, it is unique in that the photographic recording of this artificial rain and its effects offer unusual problems not encountered in ordinary sled testing. The 6,000 foot rain test section normally used produces an artificial rain with a mean drop diameter of 1.5mm, and has controllable rain drop concentration outputs plus special nozzles and tanks for isolated rain simulations. Sleds traveling at speeds up to Mach 5.5 have carried various test items through this environment so that scientists can study the effects of the rain on test items at various stations along the sled path as well as the total erosion effects after the vehicles are recovered. Detailed photographs of the test object while in the environment are best recorded by synchroballistic techniques. By sampling at intervals along the path, progressive deterioration can be recorded with space-time correlations as the test item passes through the rain field. Aerodynamic characteristics are recorded using photographic shadowgraph techniques. Engineering and general surveillance data is provided by high speed cameras and various lighting techniques.

Effect of Crop Row Spacing on Erosion and Infiltration1

AbstractSimulated rain tests were applied during four cropstage periods to corn (Zea mays L.) row spacings of 51, 76, and 102 cm and to soybean (Glycine max (L). Merr.) row spacings of 18, 51, and 102 cm. Infiltration and soil loss were measured 2 to 3 weeks, 4 to 5 weeks, and 7 to 8 weeks after planting and after harvest. Corn row spacing had little effect on ground cover or erosion during the first 5 weeks after planting. At 7 to 8 weeks, ground cover was increased slightly and erosion was reduced 24% by the narrow row (51‐cm) spacings. Narrow row spacings (18 and 51 cm) for soybeans significantly increased ground cover as early as 3 to 4 weeks after planting. Major changes in infiltration and erosion resulting from narrow row soybeans, however, were largely restricted to the last half of the growing season. During this period, infiltration was 24% greater and soil loss 35% less from narrow rows (51‐cm) than from wide rows (102‐cm). From the erosion control standpoint, the use of narrow rows for soybeans would appear to be more beneficial than narrow row corn because of the comparatively greater soil‐loss reductions.

Antibiotics as protectant fungicides against rice blast

(1) The activity in vitro of the three antifungal antibiotics Antimycin A, Blastmycin, and Blasticidin against rice blast (Piricularia oryzae) was studied. The germination of spores was completely prevented at a concentration of 50-100 mcg/ml of these antibiotics when tested by the drop culture method. The concentration at which the growth of mycelium was completely inhibited, when grown in shaken liquid media containing one of these antibiotics, was about the same as those of spore germination. In experiments to determine the concentration which completely inhibit growth, the concentration which prevented growth after 48 hours was insufficient to prevent growth after a week. The antibiotics required a concentration of 50-100mcg/ml in order to completely inhibit a week's growth.(2) The stability of the antibiotics on slide-glasses, and on leaves of rice plants growing in the greenhouse was studied by the cup or paper disc method using agar plates seeded with Piricularia oryzae. Antimycin A and Blastmycin were so stable that most of the original activity remained after 2 weeks on the leaves. Blasticidin was stable in the dark places, but decomposed gradually when exposed to sunlight. Little activity was detectable after a week on rice leaves in the greenhouse.In the simulated rain tests, Antimycin A, Blastmycin, and Blasticidin were found to be comparatively resistant simulated rainwashing. The simulated rain was approximately 10 millimeters per 10 minutes.(3) In the greenhouse Antimycin A, Blastmycin, and Blasticidin were found to be effective as a protectant fungicide, but less effective than phenyl mercuric acetate against rice blast. Rice seedlings of uniform size were selected. When their top leaves were about half expanded, and other leaves were completely expanded, plants were sprayed with a solution containing 500mcg/ ml of the antibiotic, and inolulated with the spore suspension of Piricularia oryzae after their top leaves were completely expanded. The plants were then placed in a moist chamber at about 26°C. Seven to ten days after inoculation, the number of spots on the leaves was compared.On all the leaves except the top leaves, almost the same number of leaf-spots developed on plants treated with the antibiotics as on those treated with phenyl mercuric acetate. The systemic effect of the antibiotics on the top leaves that expanded during the 4 days between the initial spraying and subsequent inoculation was inferior to that of phenyl mercuric acetate.

Corona Losses From Conductors of 1.4-Inch Diameter

A sequel to an earlier paper by Carroll and Cozzens concerning corona loss measurements for the design of transmission lines, this paper presents data resulting from comparative tests on 6 different designs of 1.4-in. conductor, the size selected for a 275-kv transmission line from Boulder Dam to Los Angeles. Data covers 3-phase, singlephase, and rain tests, and adds materially to the corona loss data previously reported.

Corona losses from conductors of 1.4-inch diameter

A sequel to an earlier paper by Carroll and Cozzens concerning corona loss measurements for the design of transmission lines, this paper presents data resulting from comparative tests on 6 different designs of 1.4-in. conductor, the size selected for a 275-kv transmission line from Boulder Dam to Los Angeles. Data covers 3-phase, single-phase, and rain tests, and adds materially to the corona loss data previously reported.