Simulation of Film Boiling Heat Transfer in Complex Geometries using Front Tracking Method

Film boiling has various industrial applications especially in heat exchangers. Studying this phenomenon on complex geometries and investigating heat transfer coefficient is desired by many industries. The numerical method used here is a finite difference/front tracking method which is developed independently for film boiling in complex geometries. The film boiling over one, two or more cylinders is simulated using this method. The effect of dimensionless parameters namely Grashof and Jacob numbers are investigated for one cylinder. The effects of spacing, angle, and diameter are investigated for two cylinders. For the case with many cylinders, the effects of different geometrical configurations (regular and staggered) and number of rows are investigated by calculating the average Nusselt number on each cylinder. It is observed that the cylinder spacing does not have any significant effect on the Nusselt number for the upper cylinder. However the angle and cylinder diameter significantly affect the Nusselt number for the upper cylinder. In regular configuration, the Nusselt numbers for the upper cylinders are relatively uniform and higher than lower cylinders. In the staggered configuration, however, the Nusselt numbers of the upper cylinders are different, non-uniform, and higher than those of the regular arrangement

COMPUTER SIMULATIONS OF POSSIBLE FUTURES FOR TWO FLOCKS OF WHOOPING CRANES

We conducted computer simulations using the program VORTEX (version 7) to project population sizes, growth rates, genetic diversity, and probabilities of extinction over the next 100 years for 2 flocks of whooping cranes (Grus americana), the Aransas/Wood Buffalo population and the experimental Florida population. Standard runs based on best estimates of demographic. genetic, and environmental parameter values were used as a baseline to which several alternative scenarios were compared. Results generally supported the conclusion of the earlier Population Viability Assessment (Mirande et al. 1991) that the AransaslWood Buffalo population will continue to grow steadily with less than a 1 % probability of extinction. It was noted, however, that a combination of negative factors such as shrinking habitat and increased probabilities of catastrophes accompanied by increased mortality rates could put this population at risk. Results for the Florida population were less optimistic. The standard run produced a population growth rate (r) of only 0.0026 for the next 100 years, and this shifted down to -0.0001 over a 200-year time frame. Adult mortality in this flock would have to be about 20% lower than the predicted value (10%) in order to raise growth rates to above r = 0.02. Amount and duration of supplementation of the Florida flock had minimal impacts on the long-tenn growth rate of the flock. It is the enduring rates of mortality, breeding, and disease risk that will have major effects on this population. For example, if disease risks tum out to be greater than the best-estimate scenario, this population could face a relatively high risk of extinction (17%). The formula for success in Florida is lower adult mortality, lower age of first breeding, lower disease risk, and higher productivity than the best-guess estimates. Fortunately, there are some potential management interventions (e.g., predator control, vaccines and health monitoring, selective introductions to balance the sex ratio of the flock) that may be able to push the odds in favor of success

Bio-ecological study of river estuaries in Guilan province

The Caspian Sea with brackish water is known as typical environment due to geo position, precious biota and the largest land-enclosed drainage area in the world. Macrobenthos were performed the main group of the Caspian Sea fauna. While they use as environmental bio-assessment, they have not completely studied in the Caspian Sea especially in estuaries environments. In this survey were studied eighteen river estuaries in Guilan province off Caspian sea southwest including Asrara, Chelevand, Lemir, Havigh, Shirabad, Khotbesara, Lisar, Karganroud, Navroud, Nokandekeh, Sefidrud, Heshmatrud, Langerud, Polerud and Chabokrud. The macro-invertebrate sampling was conducted seasonally at eight stations during autumn 2008 to autumn 2009. The macrobenthos organisms were identified as possible level in genus or species. The Shannon Wiener diversity and the Hilsenhoff biotic indices were used for evaluation of environmental quality. In this study, 69 genus identified that belong to 36 families and 16 orders. The most presentation of genus belongs to Chironomidae family with twenty six genus while others families were included forty three genus. The most average of macro-invertebrate abundance belong to order of Diptera with 35 %, subsequently the abundance of Amphipoda and Bivalvia orders occupied the second rank with 8.2 %. Orders Polychaeta, Oligochaeta and Cumacea had a low abundance during the study, however the Polychaeta showed a high abundance in some seasons and stations (up to 25%). The Plecoptera was rarely observed in some stations with high abundance. The Stenogammarus genus had the normally distribution during study, while Chironomidae genera as Eukifferiella and Cricotopus were measured in the high abundance during autumn 2008 to spring 2009. While Streblospio and Limnodrilus had the high presentation during winter and spring 2009, Cerastoderma sp. showed a high percentage in spring and summer 2009. The result of Shannon Wiener index values showed a significantly difference among regions for most seasons. There was also observed significantly difference for diversity values among stations in different seasons. According to Hilsenhoff biotic index for water quality classification; the most stations had good quality in spring 2009, while they were slightly and moderately good condition in winter 2009. The water quality of the Caspian Sea stations was in good condition as compared with the rivers estuary stations

The study of some limnological study of the Kan river in the catchment area of the Persian Gulf Martyrs Lake (Chitgar), Tehran trophic index in Anzali lagoon

This study focused on identification phytoplankton, zooplankton, benthos, fishes and relationship between biotic and abiotic parameters at three stations in the Kan river during 2014. This study identified 19 phytoplankton taxa. The findings showed, the diatoms abundance were dominated in the river. The chlorophytes abundance were recorded the lowest abundance in this study. The nutrients and water temperature were the significant abiotic parameters to increase cyanophytes and chlorophytes abundance in the Kan river. This study identified 26 zooplankton taxa. The Rotatoria and Protozoa abundance were dominated in the Kan river. Based on CCA, there was no correlation between abundance zooplankton and abiotic parameters. The biodiversity index of plankton was between 1.8 and 2 and the lake situation is located in the mesotrophic category. The study of the Kan river fishes showed, only one endemic fish species Capoeta bohsei. The length (between 38 and 270 mm, average 144±86 mm) and weight (between 1.1 and 356 g, average 108.8±146.7 g) of the C. bohsei were varied during the study period. The 19 benthos taxa were identified. The Ephemeroptera was most abundant in the benthos groups. The classification of river based on biology indicator and environmental parameters confimed that water quality is located in the moderate category

An ecological investigating on controlling Mnemiopsis leidyi population activity 6: molecular test in identification of Mnemiopsis leidyi

In this study population genetic structure of Mnemiopsis leidyi were examined by 200 samples from the Caspian Sea. Samples were collected from Guilan province (Astara region), Mazandaran province (Amir Abad region), Golestan province (Gomishan region) and north part of the Caspian Sea. 50 samples were collected from each region. DNA was extracted by phenol - chlorophorm method and its concentration was 50 to 100 nanogram. PCR was performed using 18s rRNA gene. The PCR products of samples were digested by 12 restriction endonuclease enzymes. The digested products accompanied with standard marker (50 bp lader ). In order to measure fragment size samples were run on a 6% vertical polyacrylamide gel. The fragments were visualized by silver staining of the polyacrylamide gel. In this study, Dra I and Alu I enzymes showed different digestion pattern, as each of these enzymes had two genotypes. Other enzymes had similar digestion pattern. RAPD method used by 19 random primers. Ten of nineteen primers showed polymorphism patterns. Statistical analysis of data was performed by Popgene software. In this study, the maximum of genetic variation was in north of the Caspian Sea. Also, the maximum of genetic distance was between north area and Golestan coasts (0.089) and the minimum of genetic distance was between Mazandaran and Guilan coasts (0.001). The UOGMA dendogram showed two clusters. The samples of Mazandaran , Guilan and Golestan coasts placed in one cluster and samples of north area in other cluster The genetic diversity was significantly different between samples of north area and Golestan coasts (p≤0.05). As result, there is a significant genetic divergence between some of samples. Therefore, two genetic group of Mnemiopsis leidyi were identified in the Caspian Sea

Study of Todebin dam reservoir in Zanjan province in order to aquaculture possibility

The Todebin dam reservoir has been constructed in central part of Abhar in the Zanjan province which has been studied with aquaculture purpose. This study was conducted on biotic and abiotic factors. The plankton, benthos and fishes were identified and the parasitology and bacteriology studies were performed on the lake fishes. Then the fisheries potential of the lake was calculated in respect of final fish farming amount and the fish releasing. The results showed the Bacillariophyta was dominated ِduring the study. the highest abundance of phytoplankton was between 2.1 and 12.5 million cells.l^-1 in the upper layer of lake as compared with the lower layer. The genus Cyclotella and Dinobryon belong to phytoplankton and Keratella and Polyathera belong to zooplankton were dominanted abundance. The mean biomass of benthos was varied from 5.5 to 29.5 g.m -2 and the Chironomidae had the most abundance. The ichtiology survey showed the presence of four cultured species and the Goldfish. The hydro-chemical results indicated no restriction for aquaculture activity. The oxygen average was more than 8 mg/l. The average of phosphate, nitrogen and hardness were measured 0.09±0.04, 2±0.8 and 237±94.5 mg/l., respectively. For the most hydrochemical factores, the values were significantly different between upper and bottom layers of the lake. The oxygen production and Chl-a amount were measured about 0.73 mg/l. and 7/03 µg/l., respectively. According to climatic restrictions, the cold fish culture is preferred than to culture of warm fishes. While the natural capacity of the lake was about 5 tones to warm fish culture, the fish production of trout was estimated about 40 tones. This volume will be available during four months periods and twice a year

The survey of Khandaghloo dam reservoir of Mahneshan city of Zanjan province

Reservoirs are one of the most constructions for control and water supply for different usage that could have various social an economical effects. The Khandaghloo dam reservoir with area of 100 ha located in Mahneshan city of Zanjan province and related to Parichay river watershed. Khandaghloo reservoir is valuable water body that the aim of its establishment was supply of water for agriculture farms. The reservoir has been studied for responsible and sustainable fisheries exploitation proposes. Results showed that the reservoir categorizes as eutroph to super eutroph based on different indices.Also phosphorous is limiting factor of the water body.Totally 42 genera from 6 phyla including green-blue algae cyanophyta, diatoms (Bacillariophyta), green algae, chlorophyta, euglenophyta, pyrrophyta and xanthophyta has been identified and cyanophyta was the dominant group that comprise 74.3 % of phytoplankton population. The zooplankton of the reservoir comprised 4 phyla and 20 genera. 1 genera of the protozoa and rhizopoda, 1 genra of the ciliophora ,15 genera of rotatoria, 2 genera of cladocera has been identified in zooplankton communities. Tubificidae and chironomidae has been identified in all months of the survey. The mean total length of crayfish was 130.5±20.5 mm ( 636) and mean weight was measured as 69.4±34.1 g with maximum and minimum weight of 1.9 and 207.2 g respectively .Total biomass of crayfish in Khandaghloo reservoir estimated as 3.4 tones with a range of 1.1–5.7 tones. But it is recommended not to harvest for at least two year due to high mortality of the populations.The fishes of the reservoir comprised common carp Chinese carp (silver carp, big head and grass carp) (released), Caspian kutum (accidentally released by fishery sector) and some endemic species as Siamahii. The catch of the reservoir fluctuated between 8 to 26 tones during 2000-2010.The fish production of Khandaghloo reservoir ranged from 167 to 324 kg/ha based on different methods that by consideration of 100 ha area of the reservoir, the total production of fish fluctuated between 16.7 to 32.4 tones. The fingerling restocking of Chinese carp in Khandaghloo reservoir with density of 1500 fingerling/ha recommended as 68% of phytoplanktonivorous fish (silver carp) ,12% zooplanktonivorous fish (big head), 6.6% of Crass carp and 10% of benthophagous fish (common carp)

Caspian brown trout (Salmo trutta caspius) broodstock supply in south western of the Caspian Sea (Guilan province)

Caspian trout (Salmo trutta caspius ) is one of the migratory fish species which lives and feeds in the Caspian Sea .This species distributed in south and western of the Caspian Sea . In order to rehabilitation of the Caspian trout in western area, the operation of the project started from the beginning of the fishing season of the 20112012. Specimens of the Caspian trout obtained from beach seine cooperatives and have been transferred to the fish farm in Asalem region .Totally, 44 specimens of the Caspian trout has been caught in two month period .Most of the fishes was from Kargan roud river . The mean length and weight of the brood fishes were 67.7 cm and 3122.7 g respectively .As at present Shilat uses just the broods of the Tonekaboon region for restocking of this species ,we recommend to use the broods of the western region separately for rehabilitation of the stocks of this region