Mist Conditions Research Articles

Determination of visual range during fog and mist using digital camera images

During the winter of 2008, daily time series of images of five "unit-cell chequerboard" targets were acquired using a digital camera. The camera and targets were located in the Majura Valley approximately 3 km from Canberra airport. We show how the contrast between the black and white sections of the targets is related to the meteorological range (or standard visual range), and compare estimates of this quantity derived from images acquired during fog and mist conditions with those from the Vaisala FD-12 visibility meter operated by the Bureau of Meteorology at Canberra Airport. The two sets of ranges are consistent but show the variability of visibility in the patchy fog conditions that often prevail in the Majura Valley. Significant spatial variations of the light extinction coefficient were found to occur over the longest 570 m optical path sampled by the imaging system. Visual ranges could be estimated out to ten times the distance to the furthest target, or approximately 6 km, in these experiments. Image saturation of the white sections of the targets was the major limitation on the quantitative interpretation of the images. In the future, the camera images will be processed in real time so that the camera exposure can be adjusted to avoid saturation.

Heat transfer optimization for air-mist cooling between a stack of parallel plates

A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist flow. The model predicts the optimal separation distance between the plates based on the development of the boundary layers for small and large separation distances, and for dilute mist conditions. Simulation results show the optimal separation distance to be strongly dependent on the liquid-to-air mass flow rate loading ratio, and reach a limit for a critical loading. For these dilute spray conditions, complete evaporation of the droplets takes place. Simulation results also show the optimal separation distance decreases with the increase in the mist flow rate. The proposed theoretical model shall lead to a better understanding of the design of fins spacing in heat exchangers where multiphase spray cooling is used.

Enraizamento de estacas da baunilheira (Orchidaceae)

The vanilla plant (Vanilla planifolia) could have a higher commercial production but there are problems in the efficiency of propagation. The present work was conducted with the aim of studying the effect of different substrates, in the adventitious rooting of cuttings taken at five heights in the plant stem. The cuttings were 20cm long and had two buds and one leaf and were planted in: 1) Liquid medium formed by Clark’s nutrient added of 2.5mg L-1 of IBA placed in plastic foam box with a capacity of 1.5L lined inside with transparent plastic bag and lidded with proper lid. 2) Solid substrate formed by the mixture of sand, carbonized rice husk, soil and cured cow manure in equal proportions of volume, they being placed in rigid polypropylene with a capacity of 0.28L. 3) Pre-rooting of the cuttings in liquid medium (20 days before planting), and later transferred into seedling tubes containing solid substrate. The cuttings planted in the solid substrate were maintained under intermittent mist condition controlled by a timer. After 90 days, the percentage of rooting was of 98-100%, regardless of the treatment. Larger and more vigorous sproutings were obtained from cuttings planted directly into solid substrate. Adventitious rooting of cuttings and formation of new vanilla cuttings occurred, when the cuttings were obtained from position P2 (ranging between 20 to 40cm in stem height) and planted in solid substrate in greenhouse with intermittent misting system.

Laminar premixed methane/air flame extinction characteristics influenced by co-flow water mists

Based on the tubular burner, the burning velocities, flame stretch and inhibition rules influenced by co-flow water mists were studied using a high-speed schlieren system. Moreover, the variation rules of the flame critical extinction in our burner equipment were also obtained by analyzing the process and mechanism of flame extinction and inhibition. It is shown that the flame stretch is related to the fuel concentration, co-flow fluxes and water mist diameters. For droplets with a larger diameter, the smaller the co-flow fluxes, the more obvious the flame stretch. When the water mist loading rate is rather smaller, for fuel-rich premixed flame with Le>1, the flame with larger burning rate tends to backfire more easily. Under the same water mist conditions, for fuel-lean premixed flame with Le<1, the smaller the gas concentration, the easier the flame is extinct.

Ácido indolbutírico no enraizamento de estacas semilenhosas do porta-enxerto de videira 'VR043-43' (Vitis vinifera x Vitis rotundifolia)

Este trabalho teve como objetivo avaliar diferentes concentrações de ácido indolbutírico (AIB) no enraizamento de estacas semilenhosas do porta-enxerto de videira 'VR043-43' (Vitis vinifera x Vitis rotundifolia). O experimento foi realizado na Universidade Federal do Paraná, Curitiba-PR, no período de dezembro de 2004 a janeiro de 2005. As concentrações de AIB testadas foram 0; 1.000; 2.000 e 3.000 mg L-1, sendo a base das estacas imersas nas soluções dos reguladores vegetais, durante dez segundos. Após 40 dias em câmara de nebulização, as estacas foram avaliadas. As estacas com maior porcentagem de enraizamento foram aquelas que não receberam tratamento com AIB (92,5%). A porcentagem de estacas mortas aumentou com as concentrações de AIB, e a porcentagem de retenção foliar diminuiu. Houve incremento do número médio de raízes primárias por estacas com as maiores concentrações de AIB, porém as matérias fresca e seca das raízes não diferiram significativamente entre os tratamentos. Conclui-se que o AIB não é necessário para o enraizamento de estacas semilenhosas do porta-enxerto 'VR043-43'.

Use of a Fusarium graminearum strain transformed with green fluorescent protein to study infection in wheat (Triticum aestivum)

A strain of Fusarium graminearum, the predominant causal agent of fusarium head blight (FHB) in North America, which was transformed to constitutively express the green fluorescent protein (GFP) from jellyfish, was used to perform a comparative study of the early events of colonization in wheat between FHB-susceptible ('Roblin') and FHB-resistant ('Sumai 3') cultivars. Greenhouse grown plants from both cultivars were point inoculated at anthesis with a spore suspension of GFP-Fusarium, then maintained under intermittent misting conditions until harvest. Heads were harvested for microscopy at several points in timeduring the first 24 h after inoculation and, subsequently, at longer intervals, up to 21 days after inoculation. Infected material was visualized as whole mounts; in addition, tissue was fixed and cryosectioned to examine the progress of the fungus within the wheat tissues. In both 'Roblin' and 'Sumai 3', hyphae were visible inside the floret at the point of inoculation within a few hours of the inoculation. The fungus displayed a particular affinity for the pollen and anthers of both wheat cultivars. Fungal growth was most prolific on the ovaries and stigmas of both cultivars throughout the course of the infection. In general, only after the soft tissues of the ovaries and stigmas were thoroughly colonized, did the fungus begin to move into the rachis and to the exterior of the floret. The fungus was able to spread along the spike both internally, through the rachis, and across the external surfaces of the rachis and florets. The major difference in infection pattern between susceptible 'Roblin' and resistant 'Sumai 3' was that the spread of the fungus through the parenchyma and vascular tissues of the rachis was slower and less extensive in the latter.

Método de aplicação do ácido indolbutírico na estaquia de cultivares de pessegueiro

Conduziu-se este trabalho com o objetivo de avaliar o potencial de propagação vegetativa de estacas semilenhosas de cultivares de pessegueiro tratadas com ácido indolbutírico (AIB) em dois métodos de aplicação. O experimento foi desenvolvido no Departamento de Botânica do Instituto de Biociências, Universidade Estadual Paulista “Júlio de Mesquita Filho" (UNESP), campus de Botucatu (SP). De ramos coletados de plantas-matrizes das cultivares Delicioso Precoce, Jóia 1 e Okinawa, estacas semilenhosas foram preparadas com 10 a 15 cm de comprimento, diâmetro de 5 mm e desprovidas de folhas e foram submetidas aos tratamentos de imersão rápida por 5 segundos em soluções concentradas (0, 1250, 2500 e 3750mg.L-1 de AIB) e imersão lenta por 24 horas em soluções diluídas (0, 100, 200 e 300mg.L-1 de AIB). Posteriormente, foram plantadas em bandejas de poliestireno expandido, utilizando-se vermiculita de granulometria fina como substrato e colocadas em estufa sob nebulização intermitente por 45 dias. A cultivar Okinawa (29%) e o método de imersão rápida em AIB (9%) proporcionaram os melhores resultados de enraizamento. Não se recomenda a propagação das cultivares de pessegueiro Delicioso Precoce, Jóia 1 e Okinawa em estacas semilenhosas.

Enraizamento de estacas lenhosas de porta-enxertos de pereira sob nebulização intermitente

Pesquisou-se o enraizamento de estacas lenhosas dos porta-enxertos de pereira: Taiwan Nashi-C (Pyrus calleryana Decaisne), D'água (P. communis L) e Manshu Mamenashi (P. betulaefolia Bunge), na ausência de reguladores de crescimento. As estacas lenhosas, medindo 20 cm de comprimento e contendo de 3 a 4 gemas, foram submetidas aos tratamentos com e sem incisão na parte basal e mantidas por 60 dias em ambiente de nebulização intermitente. As estacas de 'Taiwan Nashi-C' e 'D'água' apresentaram 53,8 e 51,8 % de enraizamento, respectivamente, nos tratamentos com e sem incisão. Em estacas de 'Manshu Mamenashi', verificaram-se excesso de brotações foliares e índice de enraizamento quase nulo. O método de incisão na base das estacas influenciou significativamente no enraizamento do porta-enxerto 'D'água'.

Protection of tomato seedlings against infection by Pseudomonas syringae pv. tomato by using the plant growth-promoting bacterium Azospirillum brasilense.

Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (10(7) versus 10(5) CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (10(7) versus 10(6) CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (10(5) to 10(6) CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>10(8) CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato.

Reduction of bacterial speck (Pseudomonas syringae pv. tomato) of tomato by combined treatments of plant growth-promoting bacterium, Azospirillum brasilense, streptomycin sulfate, and chemo-thermal seed treatment

Inoculation of tomato seeds with the plant growth-promoting bacterium Azospirillum brasilense, or spraying tomato foliage with A. brasilense, streptomycin sulfate, or commercial copper bactericides, separately, before or after inoculation with Pseudomonas syringae pv. tomato, the casual agent of bacterial speck of tomato, had no lasting effect on disease severity or on plant height and dry weight. Seed inoculation with A. brasilense combined with a single streptomycin foliar treatment and two foliar bactericide applications at 5-day intervals (a third or less of the recommended commercial dose) reduced disease severity in tomato seedlings by over 90% after 4 weeks, and significantly slowed disease development under mist conditions. A. brasilense did not induce significant systemic resistance against the pathogen although the level of salicylic acid increased in inoculated plants. Treatment of tomato seeds that were artificially inoculated with P. syringae pv. tomato, with a combination of mild chemo-thermal treatment, A. brasilense seed inoculation, and later, a single foliar application of a copper bactericide, nearly eliminated bacterial leaf speck even when the plants were grown under mist for 6 weeks. This study shows that a combination of otherwise ineffective disease management tactics, when applied in concert, can reduce bacterial speck intensity in tomatoes under mist conditions.

1218 超音速流れの噴霧冷却に関する実験的研究 : 噴霧装置の開発

When the liquid for cooling is sprayed into supersonic flows with high temperature, it is important to understand cooling effects by evaporation on the flows. It is required that the spray used for this purpose should be miniature to make the effects on the flow as small as possible and the droplet discharged should be evaporated easily. The foundational experiments are done to develop the atomizer which fulfills these conditions. In the present study, experimental research on figures and capacity of swirl chamber, and the figures of jet nozzle etc. is performed, and the design parameters of spray to get the desirable mist condition are clarified.

Oil Mist and Machinery Space Fires

A review is presented of the role of oil mist as a principal agent in machinery space fires. The ways in which oil mist can be produced are described as well as the distinction between mist and spray. The contrast between the oil mist conditions inside crankcases and that in the general atmosphere in machinery spaces is discussed. Methods of measuring oil mist and spray are described and equipment suitable for monitoring conditions inside machinery and in machinery spaces is discussed. Recommendations are made to improve safety on board ship and in industrial plants, and Appendices 1 through 4 cover IMO regulations and other initiatives on the oil mist hazard.

Effect of misting on transpiration and conductances of a greenhouse rose canopy

The influence of greenhouse humidity control on the transpiration rate ( λE c), sensible heat flux ( H c) and bulk stomatal conductance ( g c) of a soilless rose canopy ( Rosa hybrida, cv. First Red) was studied in a greenhouse located in the coastal area of eastern Greece. Measurements were carried out during several days in the summer (i) without air humidity control and (ii) with a mist system operating when the relative humidity of the greenhouse air was lower than 75%. The diurnal course of g c was determined from the relation linking λE c to canopy-to-air vapour pressure deficit ( D c) or from inversion of the Penman–Monteith equation. The two ways of estimating g c were in good agreement, showing a significant increase of g c under mist conditions. Covariation of radiation and humidity during the day caused diurnal hysteresis in λE c and g c. The hysteresis phenomena were less marked when the mist system was operating. Normalising g c by radiation removed most of the hysteresis and indicated a curvilinear stomatal response to vapour pressure deficit. The analysis of the energy partition at the canopy showed high negative values of the Bowen ratio ( β≈−0.7) in both conditions, indicating that canopy transpiration played a major role in cooling the greenhouse atmosphere. The contribution of the mist system to total evaporative cooling was estimated to be about 20%, with only 40–50% of the mist water being effectively used in cooling. Calculation of the crop water stress index confirmed that the crop was less stressed under misting conditions. It was concluded that the prediction of short-term variations of λE c and g c in greenhouse environments must account for the magnitude and diurnal variation of air VPD.

Propagação vegetativa de Platanus acerifolia Ait: (II) efeito da aplicação de zinco, boro e ácido indolbutírico no enraizamento de estacas

O objetivo desse trabalho foi avaliar os efeitos da aplicação do zinco (Zn), boro (B) e ácido indolbutírico (AIB) no enraizamento de estacas de Platanus acerifolia Ait. Os tratamentos consistiram do condicionamento das estacas, coletadas em quatro épocas ao longo do ano e representando diferentes tipos fisiológicos, com: sulfato e cloreto de zinco (0, 2,5, 5, 10, 20 e 40mg l-1 Zn), ácido bórico (0, 50, 100, 150, 200 e 250mg l-1 H3BO3) e ácido indolbutírico (0, 20 e 40mg l-1 AIB), através de solução aquosa, pela imersão de 3cm da base da estaca, com duas lesões laterais de 2cm, por 24 horas. A estaquia foi feita em vasos contendo como substrato uma mistura de areia média e casca de arroz carbonizada (1:1, v/v), ambas lavadas. O experimento foi conduzido por 110 dias em casa de vegetação com aspersão intermitente. No encerramento do experimento, avaliaram-se os seguintes parâmetros: comprimento e número de raízes primárias por estaca, máteria seca de raízes por estaca e percentagem de enraizamento. A aplicação isolada de Zn e B não influencia o enraizamento das estacas. O condicionamento de estacas de ramos "do ano" basais finas com AIB afeta, negativamente, o percentual de enraizamento e, positivamente, o número de raízes por estaca.

Propagação vegetativa de Platanus AcerIfolia Ait.: (I) efeito de tipos fisiológicos das estacas e épocas de coleta no enraizamento de estacas

O objetivo desse trabalho foi avaliar os efeitos do tipo fisiológico da estaca e da época de coleta no enraizamento de estacas de Platanus acerifolia Ait. Os tratamentos consistiram de uma combinação bifatorial (4 x 4), representados por quatro tipos fisiológicos de estacas de ramos ("de ano", "do ano" basal, "do ano" mediana e "do ano" basal fina) e quatro épocas de coleta (setembro/95, janeiro/96, março/96 e julho/96). A estaquia foi realizada em vasos contendo como substrato uma mistura de areia média e casca de arroz carbonizada (1:1, v/v), ambas lavadas. O experimento foi conduzido por 110 dias em casa de vegetação com sistema de microaspersão intermitente. A melhor época de coleta das estacas para o enraizamento é em julho e as estacas de ramos "do ano" basais apresentam o maior potencial de enraizamento.

Azospirillum plant growth-promoting strains are nonpathogenic on tomato, pepper, cotton, and wheat

Six strains of Azospirillum belonging to five species of plant growth-promoting bacteria (A. brasilense, A. lipoferum, A. amazonense, A. irakense, and A. halopraeference) did not cause visible disease symptoms on the roots or leaves of tomato, pepper, cotton, and wheat, failed to inhibit seed germination, and did not reduce plant dry weight when seven standard techniques for the inoculation of plant pathogens were used. Similar inoculation conditions with plant pathogens (Pseudomonas syringae pv. tomato, Xanthomonas campestris pv. vesicatoria, Xanthomonas campestris pv. translucens, and Xanthomonas campestris pv. malvacearum) induced typical disease symptoms. None of Azospirillum strains caused the hypersensitive reaction on eggplant, whereas all pathogens did. All Azospirillum strains increased phytoalexin production in all disease-resistant plant species to moderate levels, but the levels were significantly lower than those induced by the compatible pathogens. The various phytoalexins produced in plants had the capacity to inhibit growth of all Azospirillum strains. Azospirillum amazonense, A. irakense, and A. halopraeference had no apparent effect on plant growth, while A. brasilense and A. lipoferum increased the dry weight of all plant species. Under partial mist conditions, all Azospirillum strains were capable of colonizing leaf surfaces (103-107 cfu/g dry weight) regardless of the plant species. These results provide experimental evidence that Azospirillum sp. might be considered safe for the inoculation of several plant species.Key words: Azospirillum, beneficial bacteria, environmental protection, plant inoculation, plant growth-promoting bacteria.

Study of the Effect of Different Media Beds, Time, and Wounding Factors on the Rooting of Semi-hard Cuttings of Olive [Olea europaea (Roghani &amp; Zard Zeitoun C.V.)] under Mist Conditions

To determine the most proper bed, time, and wounding factors on the rooting of semi-hard cuttings of olive (Olea europaea), cuttings were selected and research was conducted at the Faculty of Agriculture of the Tehran Univ. in Karaj. The required cuttings were taken from healthy and similar mother trees at the Roodbar Research Station. Then, semi-hard cuttings of 15 cm in length and 3 to 5 mm in diameter with four terminal leaves were prepared. Then those prepared cuttings were treated with IBA at 4000 ppm and Captan fungicide at 3000 ppm before planting. This experiment was designed in a factorial with a randomized complete block, with four media bed factors for rooting in seven levels (peatmoss + perlite, sawdust + sand, peatmoss + sand, and perlite, sand, and perlite + sand), the time factor for cutting preparation in four levels (May, August, September, and March), cultivars at two levels (Roghani and Zard Zeitoun), and wounding treatment at two levels (unwounded and wounded); there were three replications (20 cuttings per replicate per each unit). The results indicate that, among the selected beds, perlite with 53% of rooting average yield has the highest and peatmoss + perlite with a rooting average of 43.8% has the lowest. As far as time is concerned, those cuttings prepared in March show the highest rooting average of 69.3%, while those prepared in August show the lowest average of 12.7%. The comparison between the two cultivars shows that Roghani, with 60.4% rooting yield, is preferred to Zard Zeitoun, with 48.2% rooting average. There were no significant differences between wounded and unwounded cuttings with regard to rooting.

Consideration for a high resolution of magnetic rotary encoder

The structure of a magnetic rotary encoder is very simple compared with an optical type and is not affected in dust and mist conditions. However, a magnetic rotary encoder with an upper limit of encoder resolution of 2000 pulses per revolution (ppr) per track has lower resolution compared with an optical encoder. In this paper, a high resolution magnetic rotary encoder with 4000 ppr per track resolution utilizing a minimum number of magneto-resistive elements has been developed by using a double interpolation method. A parameter analysis of the magnetization and the detection processes for the main magneto-resistive output voltage using a finite element method is described.

Efeitos do ácido indolbutírico e da época de coleta no enraizamento de estacas de goiabeira (Psidium guajava L.)

Este trabalho foi desenvolvido com o objetivo de verificar o efeito de concentrações de ácido indolbutírico (AIB) e da época de coleta sobre o enraizamento de estacas de goiabeira (Psidium guajava L.), oriundas de plantas produtoras de frutos de polpa vermelha e de polpa branca, em estufa com nebulizacão intermitente. Utilizou-se estacas apicais com um par de folhas e estacas medianas com dois pares de folhas, ambas cortadas pela metade. Após serem padronizadas em aproximadamente 15 cm de comprimento, procedeu-se ao tratamento introduzindo em torno de 1 cm da base da estaca em AIB na forma de pó, nas concentrações de zero, 4000, 5000, 6000 e 7000 ppm. Em seguida, colocou-se o material em sacos de polietileno perfurado, contendo cinza de casca de arroz como substrato. As épocas de estaquila corresponderam aos meses de fevereiro, abril, julho e outubro de 1993. O delineamento experimental adotado foi o de blocos ao acaso, com 3 repetições de 12 estacas por tratamento. Após 60 dias de permanência dentro da estufa, avaliou-se a percentagem de estacas enraizadas, com calo, brotadas e peso de matéria seca das raízes. Nas condições em que o trabalho foi realizado e de acordo com os resultados obtidos, verificou-se que a época de estaquia, influencia significativamente todas as variáveis estudadas. A maior média de estacas enraizadas ocorreu em fevereiro, com a estaca apical, onde obteve-se 51,52% de enraizamento. A brotação das estacas não causou indução na formação de raízes. Os tratamentos com o ácido indolbutírico (AIB), incrementaram o enraizamento e o peso de matéria seca de raízes das estacas de goiabeira. Para as variáveis brotação e percentagem de estacas enraizadas, a variedade de polpa branca foi superior somente na quarta época, correspondente ao mês de outubro.

酸性雨による生態系影響などの被害 酸性霧による影響の特徴と日本での実態

酸性雨による生態系影響などの被害 酸性霧による影響の特徴と日本での実態