The effect of anaerobic fermentation of cow manure on culture of Rutilus frisii Kutum and comparison of survival and growth factors versus traditional feeding

Rutilus firisii kutum is one of the important fish in Caspian Sea that has significant economical role to the region. The overall objective of the project is to compare the growth and survival of Rutilus frisii Kutum larvae under conventional conditions and conditions under use of organic fertilizer by anaerobic fermentation or slurry. This study was conducted in nine 1.7 hec pounds with 3 treatments with stocking densities of 1.7 million fish larva at Dr Yousefpoor Center at Siakal Village, 32km far from city of Rasht in North of Iran. The first treatment considered as control using concentrated food and grinded kilka fish. In the second treatment, the pound was supplied only by slurry for 13 days followed by concentrated fish food. The third treatment started with slurry for 13 days followed by slurry and concentrated food together. The physical and chemical parameters of water, plankton, biometry of fish, growth indices were monitored weekly. The result indicated that production was 1.7 to 2 times higher in slurry than traditional treatment also the survival rate was 1.7 times higher in slurry treatment. Slurry with several active substances is more effective and can promote the growth of zooplanktons that is the food for larval stage of Rutilus frisi kutum. Nutritional contents of phosphorous, nitrogen, calcium, magnesium, potassium, protein and lipid after anaerobic fermentation were higher in slurry treatment than control. The blue-green algae density in slurry pounds was less than control

Age structure and growth rate of (Squalius cephalus Linnaeus, 1758) in Tuji tributary from Talar River, Mazandaran Province

A structure and growth pattern of Squalius cephalus (Linnaeus, 1758) in Tuji tributary of Talar River, Mazandaran Province, was studied during the period from August 2008 till August 2009. In total, 298 fish were caught by electrofishing and fixed in 10% formalin. The weight and length of fish were measured and the age was determinated by scallometric method. The age data showed that fishes were between 0+ to 4+ age groups. Pauli`s applied growth pattern showed a positive alometric for male and female and total fish and a negative isometric for unmature fishes. The average instantaneous growth rate of European Chub showed that the age groups 2+ and 3+ with 1.1 had the fastest growth compare to 3+ and 4+ age groups with 0.89. Condition factor of specimens showed that the highest one with 1.58 (r2 = 0.983) belong to females and the lowest with 1.17 (r2 = 0.901) belong to unmature fishes. The total sex ratio (123 males to 115 females) showed no significant differences between them

The effects of slurry on larviculture of Rutilus frisii kutum and chienes carp yield and determination of efficient concentration for increasing of production

Rutilus frisii kutum is one of the important fish of Caspian Sea which has significant economical role in the region .The objective of this project is a comparative study on traditional culture of fishes versus slurry. This survey were conducted on nine pound of 1.7 hec triplicate with their treatment with stocking densities of 1.7 million fish larva at Dr yousefpoor center (Affiliated of Shahid Beheshti culture and propagation) at Siakal village , 32 km far from Rasht city in North of Iran, the first treatment considered as control which practice traditionally (using concentrated food plus grinded kilka fish) .In the second treatment for 13 days the pound supplied only by slurry then followed by concentrated fish food only .The tired treatment started with slurry for 13 days and followed by slurry plus concentrated food. The physical and chemical parameters of water, plankton, biometry of fish, growth indices such as daily weight growth (DWG), daily length growth (DLG) as well as specific ratio (SGR) were monitored weekly. The result indicate that net fish production was 1.7 to 2 times higher in slurry than traditional treatment also the survival rate were 1.7 times higher in slurry treatment . The treatment of slurry follow by addition of concentrated food plus slurry showed higher yield camper to others. Slurry with several active substances is more effective and can promote the growth of zooplanktons which is the food of larval stage of rutilus frisi kutum. In second phase of this project the effect of slurry was surveyed on Chinese carp. This experiment was conducted in triplicate with two treatment (one treatment is control which use cow manure plus chemical fertilizer and second treatment was conducted with slurry) and stocked with 2375 N/hec (Silver carp 60%, Big head 15%, common carp 17% and grass carp 8%) at June. In this survey common carp and grass carp were feed with concentrate food and fresh grasses respectively. Chemical factors were measured once for each two week and density of plankton was determined when it was necessarily. Nutritional content of phosphorous, nitrogen, calcium, potassium and magnesium after anaerobic fermentation as well as protein and lipid content with 1.4and 1.9 times respectively were higher in slurry treatment than control. The results showed that survival rate and yield were higher in slurry than control. The increasing percent of yield were 13.5, 2.6, 18.4 and 85.3 in Silver carp, Big head, common carp and grass carp respectively. The survival rate of grass carp was twice higher in slurry treatment than control. Zooplankton abundant in slurry pounds was more but blue- green algae density was less than control. Protein and lipid analysis reviled no significant difference between control and slurry. In general the result indicate that the slurry with higher nutritional content is more effective on the survival and growth rate of fishes and also is more efficient in proliferation of plankton in particular zooplankton

Lean flammability limits for stable performance with a porous burner

Applications of porous burners are of high interest due to many advantages such as extended lean flammability limit in comparison with free flame structures. In this work, laminar premixed flame propagation of methane/air mixture in a porous medium is numerically investigated. An unsteady one-dimensional physical model of a porous burner is considered, in which the flame location is not predetermined. The computational domain is extended beyond either side of the porous medium to accurately model reactions close to the edges of the solid matrix. After validation of the model and performing a baseline simulation, a parametric study is carried out to investigate the lean flammability limits of the burner and the unstable flash-back/blow-out phenomena. Stable performance diagrams are given for two controlling parameters of turn-down ratio and porous medium porosity. The simulation results indicate that the stable performance range of the burner is extended when the equivalence ratio increases; however, the blow-out region expands with an increase in the firing rate. For constant values of porosity and firing rate, increasing the equivalence ratio can change the operating regime of the burner from blow-out to a stable condition. It is observed that by the variation of porosity in the range of 0.6-0.9, and for the equivalence ratios of more than 0.6, the flame flash-back cannot occur. An equivalence ratio of 0.43 is found to be the lower limit at which the flame stabilizes in the matrix.Porous burner Lower flammability limit Flash-back Blow-out Turn-down ratio Matrix porosity