25 research outputs found

    Evaluating Occupational Accidents and Their Indices In a Refining and Distributing Company of Petroleum Products of Mahshahr 2008-2010

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    Technological progress and oil industry development accompanies have a high rate of risk. This study was conducted with the aim of evaluating occupational accidents and related indicators for decreasing the number of damages by offering control measures. In this descriptive-analytical study, essential information was extracted from the records and agendas of the technical safety committee and the evaluation of accident frequency was done based on the accident type, the time and the location of its occurrence, environmental condition, root factors, and demographic variables of the injured. The relationship between repetition, severity, frequency of the accidents and marital status of the company’s personnel was also studied. Accident analysis was done by Chi square test . The occurrence of about 102 accidents was reported in an incident evaluation, which was done between the years 2008 and 2010. The average age of the injured was 29.1± 8.61. Accidents and clashes were 31.4% of the accidents and falling from height 21.6% of them. Many of the accidents occurred in plumbing activities (24.5%), tank construction (23.5%), and civil operations (15.7%). 47% of the accidents happened in 2009, 43% in 2010, and 10% in 2008. Occurrence rate of accidents was 48.1 and their intensity rate equaled 0.15 for one million working hours. The relationship of accident type and marital status was a meaningful relationship based on Chi-square test (P = 0.014); this test showed the relationship of accident type and its reasons a significant one as well. (P = 0.035) Considering the calculated coefficients and evaluated factors in this study, safety training, constant inquiring of sub-activities, inserting safety and HSE provisions and guidelines to the contractors’ contracts and monitoring their application would be effective in decreasing the number accidents.

    Transpiração e crescimento foliar de crisântemo em função da fração de água transpirável no substrato

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    The objective of this work was to evaluate the response of transpiration and leaf growth of chrysanthemum (Dendranthema grandiflorum) cultivars to available water in the substrate, represented by the fraction of transpirable substrate water (FTbSW). The experiments were performed in two periods, in a completely randomized design, with four chrysanthemum cultivars (Cherie White, Bronze Repin, Yoapple Valley, and Calabria), under two substrate water conditions (with or without water stress), with 10 replicates. Plants were grown in a greenhouse, in 2.8-L pots with substrate. FTSbW, transpiration, and leaf growth were measured daily, during the period of water deficit. The average threshold FTSbW, indicating that transpiration and leaf growth began to be affected, was respectively 0.63 and 0.68 for 'Cherie White', 0.60 and 0.69 for 'Bronze Repin', 0.53 and 0.59 for 'Yoapple Valley', and 0.51 and 0.54 for 'Calabria'. Available water decrease in the substrate reduces leaf growth before restricting transpiration. The Cherie White and Bronze Repin cultivars are more tolerant to water deficit by closing the stomata earlier and retaining more water in the substrate than the Yoapple Valley and Calabria cultivars.O objetivo deste trabalho foi avaliar a resposta da transpiração e do crescimento foliar de cultivares de crisântemo (Dendranthema grandiflorum) ao conteúdo de água disponível no substrato, representado pela fração de água transpirável no substrato (FATSb). Os experimentos foram realizados em dois períodos, em delineamento inteiramente casualizado, com quatro cultivares de crisântemo (Cherie White, Bronze Repin, Yoapple Valley e Calabria), em duas condições hídricas (com ou sem deficiência hídrica), com 10 repetições. As plantas foram cultivadas em casa de vegetação, em vasos de 2,8 L preenchidos com substrato. A FATSb, a transpiração e o crescimento foliar foram determinados diariamente durante o período de deficiência hídrica. As FATSb críticas médias, indicativas de que a transpiração e o crescimento foliar começam a ser afetados, foram respectivamente de 0,63 e 0,68 para 'Cherie White', 0,60 e 0,69 para 'Bronze Repin', 0,53 e 0,59 para 'Yoapple Valley', e 0,51 e 0,54 para 'Calabria'. A diminuição da água disponível no substrato provoca a redução do crescimento foliar antes de restringir a transpiração. As cultivares Cherie White e Bronze Repin são mais tolerantes ao deficit hídrico por fechar os estômatos antes e conservar mais a água no substrato do que as cultivares Yoapple Valley e Calabria

    Transpiration and leaf growth of potato clones in response to soil water deficit

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    Potato (Solanum tuberosum ssp. Tuberosum) crop is particularly susceptible to water deficit because of its small and shallow root system. The fraction of transpirable soil water (FTSW) approach has been widely used in the evaluation of plant responses to water deficit in different crops. The FTSW 34 threshold (when stomatal closure starts) is a trait of particular interest because it is an indicator of tolerance to water deficit. The FTSW threshold for decline in transpiration and leaf growth was evaluated in a drying soil to identify potato clones tolerant to water deficit. Two greenhouse experiments were carried out in pots, with three advanced clones and the cultivar Asterix. The FTSW, transpiration and leaf growth were measured on a daily basis, during the period of soil drying. FTSW was an efficient method to separate potato clones with regard to their response to water deficit. The advancedclones SMINIA 02106-11 and SMINIA 00017-6 are more tolerant to soil water deficit than the cultivar Asterix, and the clone SMINIA 793101-3 is more tolerant only under high solar radiation

    Prediction of CEC using fractal parameters by artificial neural networks

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    The prediction of cation exchange capacity from readily available soil properties remains a challenge. In this study, firstly, we extended the entire particle size distribution curve from limited soil texture data and, at the second step, calculated the fractal parameters from the particle size distribution curve. Three pedotransfer functions were developed based on soil properties, parameters of particle size distribution curve model and fractal parameters of particle size distribution curve fractal model using the artificial neural networks technique. 1 662 soil samples were collected and separated into eight groups. Particle size distribution curve model parameters were estimated from limited soil texture data by the Skaggs method and fractal parameters were calculated by Bird model. Using particle size distribution curve model parameters and fractal parameters in the pedotransfer functions resulted in improvements of cation exchange capacity predictions. The pedotransfer functions that used fractal parameters as predictors performed better than the those which used particle size distribution curve model parameters. This can be related to the non-linear relationship between cation exchange capacity and fractal parameters. Partitioning the soil samples significantly increased the accuracy and reliability of the pedotransfer functions. Substantial improvement was achieved by utilising fractal parameters in the clusters

    Prediction of CEC Using Fractal Parameters by Artificial Neural Networks

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    The prediction of cation exchange capacity from readily available soil properties remains a challenge. In this study, firstly, we extended the entire particle size distribution curve from limited soil texture data and, at the second step, calculated the fractal parameters from the particle size distribution curve. Three pedotransfer functions were developed based on soil properties, parameters of particle size distribution curve model and fractal parameters of particle size distribution curve fractal model using the artificial neural networks technique. 1 662 soil samples were collected and separated into eight groups. Particle size distribution curve model parameters were estimated from limited soil texture data by the Skaggs method and fractal parameters were calculated by Bird model. Using particle size distribution curve model parameters and fractal parameters in the pedotransfer functions resulted in improvements of cation exchange capacity predictions. The pedotransfer functions that used fractal parameters as predictors performed better than the those which used particle size distribution curve model parameters. This can be related to the non-linear relationship between cation exchange capacity and fractal parameters. Partitioning the soil samples significantly increased the accuracy and reliability of the pedotransfer functions. Substantial improvement was achieved by utilising fractal parameters in the clusters

    Physiological and morphological responses of rice (Oryza sativa L.) to varying water stress management strategies.

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    Abstract Sustainability of rice production under limited water conditions is threatened by increasing irrigation water scarcity. Therefore, physiological and morphological responses of rice to varying water stress management strategies should be determined. The physiological and morphological responses of a semi dwarf rice (Hashemi cultivar) to water stress intensities (mild and severe, i.e., short-duration of stress with early recovery and long-duration stress with late recovery, respectively) and timing (mid-tillering, booting and 50% of flowering) were studied in a pot experiment. The severe water stress at mid-tillering significantly (P<0.05) decreased plant height and the number of panicle per hill and delayed flowering. The severe water stress at different growth stages caused substantial yield losses by large percentage of unfilled grains. Root weight was highest under mild water stress at 50% of flowering followed by severe water stress at mid-tillering. Relative transpiration (RT) was not lowered until the thresholds of the fraction of transpirable soil water (FTSW), plant available water (PAW) and soil water tension (h) reached to 0.46 (-), 0.9 (-) and 78.0 kPa, respectively. These values were approximately close to those obtained for the relative leaf development rate (RL), as 0.44 (-), 0.91 (-) and 74.6 kPa, respectively. These results indicated that transpiration and leaf development rates have the same sensitivity to water deficits. However, in the mid-tillering, RL was more sensitive to water deficit than RT. The results of thresholds for RT indicated that booting stage is more sensitive than other stages. It is concluded that water tension of 1500 kPa as considered for permanent wilting point is not suitable for rice. Therefore, PAW can not be a suitable soil-water criteria for rice plants that are sensitive to water deficit. Furthermore, It is concluded that Hashemi cultivar is very sensitive to mild and severe drought stress during reproductive stage
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