55 research outputs found

    Heat Transfer to Separation Flow in Heat Exchangers

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    Recovery of Natural Antioxidants from Fruit Juice Industry Residuals by Ultrasound-Assisted Extraction and Response Surface Methodology

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    Fruit processing industries produce by-products that are good sources of natural antioxidants. These residuals are non-toxic and available in large quantities. A central composite design (CCD) and response surface methodology (RSM) were used to optimize experimental conditions. The processing variables were solvent type, solvent to solid ratio, ethanol concentration, temperature, and time. The responses were total phenolic content (TPC), scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and yield. The optimal conditions were 70% ethanol— water mixture as a food grade solvent, temperature of 35 °C and extraction time 60 min for obtaining extracts with maximum of total phenolic content. Predicted values for total phenolic content in pear, apricot, and peach were 24.7, 19.3, and 10.4 mg gallic acid equivalents per 100 g fruit residual, respectively

    Simulation of heat transfer to separation Air flow in a concentric pipe

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    Flow separations occur in various engineering applications. Computational simulation by using standard k-ε turbulence model was performed to investigate numerically the characteristic of backward-facing step flow in a concentric configuration. This research is focused on the variation of Reynolds number, heat flux and step height in a fully developed turbulent air flow. The design consists of entrance tube, inner and outer tubes at the test section. The inner tube is placed along the entrance tube at the test section with an outer tube to form annular conduit. The entrance tube diameter was varied to create step height, s of 18.5 mm. The Reynolds number was set between 17050 and 44545 and heat flux was set between 719 W/m2 and 2098 W/m2 respectively. It is observed that the higher Reynolds number with step flow contribute to the enhancement of heat transfer. The reattachment point for q=719 W/m2 is observed at 0.542 m, which is the minimum surface temperature. The experimental data shows slightly lower distribution of surface temperature compared to simulation data. As for the same case in experimental result, the minimum surface temperature is obtained at 0.55 m. The difference between numerical and experimental result is 0.008 m. Finally, it can be inferred that utilizing the computational fluid dynamic package software, agreeable results could be obtained for the present research. Keywords: Numerical Simulation; Heat Transfer; Turbulent Flow; Computational Fluid Dynamics; Backward Facing Ste

    Basic effects of pulp refining on fiber properties- a review

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    The requirement for high quality pulps which are widely used in paper industries has increased the demand for pulp refining (beating) process. Pulp refining is a promising approach to improve the pulp quality by changing the fiber characteristics. The diversity of research on the effect of refining on fiber properties which is due to the different pulp sources, pulp consistency and refining equipment has interested us to provide a review on the studies over the last decade. In this article, the influence of pulp refining on structural properties i.e., fibrillations, fine formation, fiber length, fiber curl, crystallinity and distribution of surface chemical compositions is reviewed. The effect of pulp refining on electrokinetic properties of fiber e. g., surface and total charges of pulps is discussed. In addition, an overview of different refining theories, refiners as well as some tests for assessing the pulp refining is presented. (C) 2014 Elsevier Ltd. All rights reserved

    Studying native fishes in Hamadan province

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    Studying native fishes of Hamadan province have been done in 159 stations from 51 important water resources (wetland, reservoir, spring, river and qanat) using with electric tool, cast-net, seine and gill-net gears from July 2010 to Oct. 2011 and the main aims were species identifying and determining their distribution and abundance in the studied area. In the study, 33411 fish specimens are caught in 257 times of sampling and selected randomly about 8500 individual and laboratory works showed the fish belong to 37 species from 7 families. Cyprinidae with 25, Nemacheilidae with 6 and Sisoridae with 2 species had the most diversity and Cobitidae, Poeciliidae, Salmonidae and Mastacembelidae had only a representative. 31 fish species were native or endemic and 6 species were alien. Fish species existed in all rivers of Ghezelozan and Sirvan sub-basins but there were not any fish in 10 rivers of Ghara-Chai sub-basin and in 6 rivers of Gamasiab sub-basin, too. Also, it was observe 1-3 fish species in 15 rivers, 4-6 fish species in 10 rivers, 7-10 fish species in 5 rivers and more than 10 fish species in 4 main water resources and Gamasiab sub-basin with 32 fish species was the most diversified and Ghezelozan sub-basin with 2 fish species was the least diversified. There were any species to 4 (mostly 1 or 2) fish species in studied qanats in Ghara-Chai and Gamasiab rivers sub-basins. 23 fish species existed in a subbasin, 12 species in 2 sub-basin, Capoeta capoeta in 3 sub-basin and Squalius cephalus in all sub-basins of studied area. Alburnoides nicolausi,Capoeta aculeata and Alburnus mossulensis have had the most frequency. Studying fish abundance showed Oxynoemacheilus argyrogramma with 17.8%, Garra rufa with 12.3%, A. mossulensis with 12.1% and C. aculeata with 10.2 % of total number of caught fish specimens are dominant. S. cephalus, Capoeta damascina, C. aculeata, C. trutta, Chondrostoma regium and A. mossulensis have had sport fishing value but Acanthobrama marmid, Oxynoemacheilus kiabii, Oxynoemacheilus kermanshahensis, Turcinoemacheilus kosswigi, Alburnus caeruleus and Mastacembelus mastacembelus have biodiversity value for being endemic or having limited habitats in Iran

    Trout farms and other human activities effects on Cheshmehkileh river ecosystem in Tonekabon

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    Cheshmehkileh River and adjacent mountainous streams, play a strategic role as a historical axis for anthropogenic civilization, human welfare also habitat and migration pathway of commercial – biologic valuable fishes e.g. Caspian trout, Caspian kuttum, members of Cyprinidae family in south Caspian Sea drainage. Treats such as overfishing of Caspian trout and Red spotted trout stocks in mountainous headwaters, barriers construction and manipulations those are out of river carrying capacity developed by human activities, affected normal function of river as well. Sand mining big factories establishment next to the river, legal and illegal trade of river sediments, direct entry of Tonekabon landfill leakage into the river, development of Rainbow trout farms since 3 decades and huge effluents into the river containing dead fish and types of solids, escapement of cultured Rainbow trouts into the river, … are major minimum factors which needs basic information for integrating inclusively drainage management system. Cheshmehkileh River contains Headwaters of Dohezar (Daryasar & Nusha), Sehezar and Valamroud rivers during 13 monthly sampling phases between September 2009 and October 2010 based on macrozoobenthoses investigations by EPT, EPT/C EPA protocols, measurements of nominated physic-chemical and microbiologic parameters. Probability of Rainbow trouts escapement and invasion, existence, nutrition in Cheshmehkileh environment indeed investigated. Data analysis explained significant differences (P<0.05) between groups of measured parameters in different sampling stations. Dendogram of clustered analysis based on consolidation of major biologic/ physic-chemical and microbiologic parameters, separated stations No. 1, 3, 2, 4 in one group and remained classified in different groups. Station 8 and 9 similarly separated which expressed general similarities according to Sehezar river environment which were differs in comparison with other stations. Station 11 separated according to its natural quality of water and environment. Similarities between station 10 to Sehezar river stations 8 and 9 expressed general influence of Sehezar River more than Dohezar River in Cheshmehkileh condition especially in station No. 10. High scores of EPT and EPT/C indices in upstream stations 1, 3 and 8 also low score of indices in stations 7, 13 and 6 expressed levels of environment quality between these groups of stations. Maximum average biomass of macroinvertebrates belongs to Trichoptera order in Cheshmehkileh River. Significant decrease of biomass in stations 11, 12 and 13 in comparison with other stations stated environment degradation in mentioned stations relevant to excessive sand mining as well. Pollution resistant groups of invertebrates significantly increased in downstreams against upstream stations. Also disappearing of Plecoptera order in station No. 7, 9, 10 and 13 stated low quality of environment in comparison with upstream stations. Confirmation of effects quality and quantity for point and non-point sources of imported pollutants require specific management considerations in order to present exploitations, pollutants control and emergencies for river monitoring in forthcoming years

    The feasibility of Gamasiab river area fish farming of rainbow trout (Oncorhynchus mykiss)

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    This study was carried out about 15 months to determine suitable locations for the development of aquaculture across the Gamasiab river of Hamedan province in 2007 - 2008. Physicochemical parameters and macro benthic invertebrates fauna 15 and 13 stations respectively every 45 days and seasonally fish identify in 8 stations were performed according standard methods. The average water temperature was 12.8±3.7 oC, minimum and maximum dissoled oxygen were 2.6 and 12.5 mg/lit respectively during the study. The pH range was between 7.5-8.8 , the minimum and maximum Ec was 250 and 750 µmos/cm in Mehr and Tir. The transparency range was recorded about 1-103 F.T.U. The uder factors such as amount of suspended materials: 0.01-0.1 mg/l, amount of BOD5: 0.05-6.2 mg/l and COD: 30 (minimum) and 70.57 (maximum) were recorded. The total solids material (T.S.S) were less than 1 mg/lit. Totally 37 groups of bentic organisms were identified which 11 groups of them were appertained to pollution sensitive orders containing Ephemeroptera, Trichoptera and Plecoptera. During fish population studied 21 species belonging 5 family were identified. Based on obtained results of biological, ecological, economic and social parameters, 10 sites in 7 areas were suitable identified for fish rearing and 12 aquaculture programs (10 plan for fish rearing and 2 plan for increasing fish production of (Oncorhynchus mykiss). The minimum and maximum production capacity in mentioned places was estimated about 1675 and 3850 tons respectively
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