13 research outputs found

    Asymptotic theory of diffusion-flame extinction with radiant loss from the flame zone

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    Laminar diffusion flames in counterflow configurations such as stagnation-point boundary layers are analyzed by methods of matched asymptotic expansions with large parameters being the temperature sensitivities of the rates of chemical heat generation and radiant heat loss. Formulas are derived defining critical conditions for flame extinction, including influences of radiant loss

    Assessing changes shoreline in Dayyer city using the landsat satellite data, sensor TM and OLI 1991 and 2014 years

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    Coastal environments are considered the most sensitive system environments. In terms of environmental Coastal areas because of the sensitive and productive ecosystems have high importance and value. Having knowledge of the coastline’s behavior can help of the coastal better management. The aim of this study is to assessing the application of the OIF utility index factor in the assessment of coastline changes in Dayyer city, Using Landsat satellite images sensor TM and OLI 1991 and 2014 and the software are 2013®MATLAB and ArcGis 9.3. For the separation of land and water, OIF index value for all different band combinations in the application MATLAB® 2013 was calculated and then high-pass Sobel filter with 3 × 3 masks was applied to the images. Then digitization process during different periods in application environments ArcGis 9.3 was done manually and with high precision. The results of the survey the coastline from 1991 to 2014 show moving the coastline to the sea side (sedimentation) and landward (erosion), Which totals 33/784 square kilometers sedimentation and 9/132 square kilometers erosion shows from 1991 to 2014, in Dayyer city occurred because of the construction of piers, installations manmade and natural factors

    The evaluation of sea surface temperature and the relationship between SST and depth in the Persian Gulf by MODIS

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    Sea surface temperature (SST) is one of the most widely used parameters in studies pertaining to oceanography and the atmosphere. Water surface temperature changes from time to time and plays a significant role in waters and activities of atmospheric system, survival of marine creatures, sea currents, level of salinity and other conditions of sea and lake waters. In order to provide SST images over the Persian Gulf, the MODIS on board the Aqua Satellite was used. Applying lighting assessment out of images from Modis 21-Level 1B Calibrated Radiances -1km in Persian Gulf and the Bushehr sea station (Bouyeh) from global algorithm specified for above sensor was used to estimate the sea surface temperature. With function of Matlab software to extract data of satellite images, and GIS software to convert the matris obtained, the maps of sea surface temperature were used. 48 images taken in 2008, 2009, 2012, and 2013 were selected. Their correlation coefficient was 0.75, 0.86, and 0.75 respectively. Also, the coefficient of determination obtained was 0.86, 0.90, 0.94 and 0.86 respectively. Finally, taking the 31 band temperature into consideration for the years 2008, 2009, 2012, the temperature differences of bands 31 and 32, the sensor angle as independent factors and the Bouyeh temperature as the affiliated factor, the global algorithm coefficient for the Persian Gulf was calibrated through SPSS. In order to check the correctness of the suggested algorithm, the sea surface temperature was reexamined with satellite images from 2013 and the obtained correlation coefficients were 0.96 and 0.94. According to this study, apart from depth, other factors such as sea currents and latitude also have an effect on sea surface temperature. The amount of temperature change especially in the northern and central latitudes, have an inverse relation with depth

    Validation of aerosol optical depth using AERONET ground stations in marine areas (Case Study: Persian Gulf)

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    Dust prediction such as prediction of wind and rain needs to synoptic information to the earth's surface, upper layers of the atmosphere, the prediction maps of land surface and upper levels as well as using radar and satellites. In the meantime, radar and satellite observations included remote sensing can be useful in prediction accuracy. The purpose of this study, use of remote sensing technology and MODIS images to estimate dust optical depth on the Persian Gulf surface and estimating the linear correlation relationship between the dust measurements in ground and atmospheric. The dust optical depth calculated using the code developed in MATLAB software. Evaluation of extracted data conducted using Pearson correlation coefficient, RMSE and RMSD index. In this study, optical depth obtained from image processing compared with the optical depths obtained from AERONET network. The evaluation results showed a high and significant correlation between the obtained optical depth and optical depths obtained from AERONET network (R 2 =0.99). The best and most suitable mode demonstrated for 1.243 and 1.632 bonds. At all stations, AOD value obtained from satellite image is bigger than AOD amount corresponding to the AERONET station and the algorithm used has overestimated. The cause of this more estimate can be use of limited particle's effective radius, because the scope of this effective radius is limited at the distribution of particle size in log-normal. Error resources at the retrieving particulate matter was defined such as sensor calibration error, pollution on the radiation angle, or poor predictor of water reflection

    Evaluation of optical depth from MODIS satellite imagery in the Persian Gulf

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    Atmospheric dust particles originating in the arid and semi-arid regions of the world are known to be principal sources of mineral dust. The use of satellite remote sensing dust, the potential of this technique is created to provide valuable information to assist in the design of network measurement and estimation dust in marine environments. Dust deposited provides key nutrients such as iron to oceanic phytoplankton. Aerosol optical depth were reviewed in the study between March 2008 and December 2013 in the Persian Gulf. Aqua and Terra satellites for the MODIS sensor data as well as aerosol data (PM10) and Environmental stations and optical depth stations AERONET, used to evaluate the aerosol optical depth. The results showed that the data of MODIS AOD has acceptable accuracy and very high correlation between the values measured by MODIS and network AERONET, there (correlation coefficient: 90/0). Comparison between AOD values derived from measurements by satellites Aqua and Terra MODIS sensor and the amount of aerosol (PM10) estimated environmental stations in the Persian Gulf region also took place. The results showed that between these two values correlated to the Aqua and Terra satellites in the study area, and the correlation coefficient was greater in summer than winter. The results of this study showed that the optical depth data from the MODIS satellite images can provide accurate information dusts the Persian Gulf

    Population genetic study on croaker species Atrobucca nibe in Persian Gulf and Oman Sea using molecular methods

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    Black Mouth Croaker (Atrobucca nibe) is of significant value from the economics point of view. In the following study, the genetic diversity of Atrobucca nibe has been investigated using the PCR-sequencing method from three different regions of the Persian gulf and Oman Sea, namely Chabahar in the Sistan and Baluchestan and Jask in Hormozgan Province of Iran and Fujairah in the Fujairah Emirate of the United Arab of Emirates. The purpose of the following exploration has essentially beencoined to further the study of Atrobucca nibe genetic diversity and its population structure in the Persian Gulf and Oman Sea. For this purpose, a number of 54 fish have been collected from the aforementioned regions. The DNA of the fish had been extracted through the Ammonium Acetate method and the quality of the DNAs were analyzed via the spectrophotometry and furthermore the quantity of the extracted DNA were assessed viaelectrophoresis. Polymerase Chain Reaction (PCR) was conducted on the targeted DNAs and thenceforth DNA sequencing was carried out. Subsequently, through sequencing it was discovered that the D-loop region in the mitochondrial DNA (mtDNA) of Black Mouth Croaker,contained 270 base pairs (bp). For the purpose of analyzing the genetic diversity of Atrobucca nibe and its population structure in the Persian Gulf and Oman Sea, the following softwares have been conducted, namely theBioEdit, Arlequin, Dnasp and Mega5 software. Furthermore, the Kimura 2-parameter was used for the purpose of genetic distance analysis. Through observations of average levels of FST between the regions, it can be summed up that genetic differences do exist among the present populations. On the grounds of the obtained results from the Persian Gulf and Oman Sea, it can be concluded that there currently are three different populations of Atrobucca nibe residing in the waters of Sistan & Baluchestan, Hormozgan and Fujairah
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