216 research outputs found

    Histomorphometrical study of silver carp fish testis in two age classes

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    In this research, morphological and histomorphometrical structure of testis of 20 silver male carp fish were studied in two classes or groups. Group1 was composed of 10 fish with average (±SD) weight of 1.247+0.656kg and average(±SD) length of 43.675+1.414cm with about 2 years age, Group2 was composed of 10 fish with average(±SD) weight of 5.716+0.519kg and average(±SD) length of 81.5+1.643cm. Average (±SD) weight of testis were 2.34+1.47gr and 83.33+25.81gr with average (±SD) GSI of 0.187+0.224 and 1.457+4.974 in groups 1 and 2 respectively. Samples from testis were taken by maximum thickness of 0.5cm and after fixation in bouin , s fixative and 5-6µm thickness section were made routine paraffin embedding method and stained by Hematoxylin-Eosin and PAS staining. The microscopic results showed that the silver carp testis was lobular and cystic type in two groups. In group 1, there was no spermatozoon activity and PGCs were only germ cells in the cysts. But in group2, the numbers of PGCs were decreased significantly and spermatogenic cells were seen in different phases including spermatogonia, primary and secondary spermatocysts, early and late spermatid, and spermatozoa which each one was located in a separated cyst. There was no significant difference in nucleus diameter of PGCs in testis of group1 (6.97+0.438µ) and group (6.13+0.438µ). In group2, the nucleolus diameter of spermatogonia was 2.97+0.112µm, primary spermatocyt 3.59+0.107µ, early spermatid 1.59+0.761µ, late spermatid 1.24+0.132µ, spermatozoa 1.16+0.054µ, and the length of spermatozoia 17.412+1.946µ. The interesting finding was immature testis in fish of group 1 with average weigh (1.247+0.656kg) and average length (43.675+1.414cm) in about 2 years age and mature testis in fish of group 2 with average weight of (5.716+0.519kg) and average length of (81.5+1.643cm) with about 4 years age in Khuzestan climate conditions

    Influence of tillage depth, penetration angle and forward speed on the soil/thin-blade interaction force

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    In this study, an experimental investigation regarding the influence of three independent variables including tillage depth (10, 15, 20 cm), angle of attack (60, 75, 90 degrees) and forward speed (0.5, 1, 1.35, 1.7 m/s) on draft force of a thin blade is presented.  Chisel plow in this research was constructed in two furrows with a blade width of 3 cm and a maximum depth of 25 cm (the distance between two blades was 1 m).  Some changes were made in the chassis of the chisel plow in order to obtain different attack angle of the blade.  The experimental work was then complemented with a new theoretical model for predicting the blade force using dimensional analysis method.  The final expression for estimating the pull resistance is as a function of several soil engineering properties (soil bulk density, soil adhesion and cohesion coefficients), blade parameters (blade width and blade rake angle) and operational conditions (tillage depth and forward speed).  Finally constants of the model were computed based on obtained experimental data.  The proposed model properly estimated the draft force of a thin blade.  Results obtained in this study indicate the stronger influence of tillage depth on the pulling force of a thin soil-working blade compared to the penetration angle and forward velocity.  The average error for the vertical blade with depth of 20, 15 and 10 cm were obtained equal to 4.5%, 4% and 1.5%, respectively.   Keywords: tillage, thin blade, chisel plow, interaction force, dimensional analysi

    Microring resonator made by ion-exchange technique for detecting the CO2, H2O, and NaCl as cladding layer

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    A system of Microring Resonator (MRR) based the comb-like sensor devices has been simulated. We present a Silicon-On-Insulator (SOI) ring resonator based on refractive index sensor. The novelty of the architecture lies in the capability to sense the shifts of multiple peaks simultaneously with an MRR waveguide. The behavior of optical MRRs, especially when functioning as refractive index sensors, is studied. Resonant wavelength, i.e. the wavelength at which the transmission spectrum exhibits a dip (peak) depends on the geometrical characteristics of the circular waveguide and the effective refractive index of the propagating mode. The previous studies have shown that the depth and vertical symmetry of buried waveguides are noticeably affected by the field perturbation. One of cost effective and low loss methods can be the technology known as ion-exchange which uses the glass substrates and the AgNO3/NaNO3 salt-melt at different temperatures and duration can be deposited on the glass substrates. Afterward, an MRR was designed on the glass substrates, where the effect of the carbon dioxide (CO2), Dihydrogen oxide (H2O), and sodium chloride (NaCl) as the cladding on the ion-exchange waveguide studied. Within the compare of the resonance in drop port and throughput port, it can understand that they roughly have the same distance of wavelength in the resonance. H2O is one of the materials showing higher Qfactor and FSR while it was in drop port also in throughput CO2 was the highest in these parameters. Keywords: Microring Resonator (MRR), Sensor, Ion-exchang

    Efficient Strategies for Elimination of Phenolic Compounds During DNA Extraction From Roots of Pistacia Vera L.

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    Optimization of DNA extraction protocols for plant tissues and including endophytic microorganisms is a critical step of advanced plant-microbe interaction in agricultural studies. Pistachio (Pistacia vera L.) root tissue contains high levels of polyphenols have been known as major extract contaminants and inhibitors of enzymatic activities during amplification. The present study aimed to develop reliable strategies to purify DNA from Pistachio root samples. Inhibiting substances were removed from DNA through a process including extraction with hot detergent contains SDS-Tris- EDTA, AlNH4(SO4)2.12H2O as chemical coagulating factor and CTAB-NaCl. Following typically organic extraction/alcohol precipitation, denaturing agarose electrophoresis performed to purify probable remain contaminants. The purified DNA was enough free of polyphenols based upon loss of color and spectral quality (260/230>1.6) and efficiently amplified during polymerase chain reaction particularly in the present of GC-clamp primers. This method proved well with detection of Glomus sp. (arbuscular mycorrhiza fungi) associated with Pistacia vera L. using denaturing gradient gel electrophoresis (DGGE)

    Application of Deep Neural Network to Predict the High-Cycle Fatigue Life of AISI 1045 Steel Coated by Industrial Coatings

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    In this study, deep learning approach was utilized for fatigue behavior prediction, analysis, and optimization of the coated AISI 1045 mild carbon steel with galvanization, hardened chromium, and nickel materials with different thicknesses of 13 and 19 mu m were used for coatings and afterward fatigue behavior of related specimens were achieved via rotating bending fatigue test. Experimental results revealed fatigue life improvement up to 60% after applying galvanization coat on untreated material. Obtained experimental data were used for developing a Deep Neural Network (DNN) modelling and accuracy of more than 99%.was achieved. Predicted results have a fine agreement with experiments. In addition, parametric analysis was carried out for optimization which indicated that coating thickness of 10-15 mu m had the highest effects on fatigue life improvement

    Numerical Simulation of the Performance and Emission of a Diesel Engine with Diesel-biodiesel Mixture

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    IntroductionIncreasing industrialization, growing energy demand, limited reserves of fossil fuels, and increasing environmental pollution have jointly necessitated for exploration of a substitute for conventional liquid fuels. Vegetable oils can be used as alternatives to petroleum fuels for engine operation. These oils are mixtures of free-fatty acid molecules to contain carbon, hydrogen, and oxygen atoms. The ability to simulate the process of converting chemical energy to heat, energy users of computational fluid dynamics software in the design, analysis, and optimization of high-tech tools. Also, simulation saves time and reduces costs, workforce, and the space required.Materials and MethodsIn this research, a one-dimensional computational fluid dynamics solution with GT-Power software was used to simulate a four-cylinder, four-stroke, direct injection diesel engine to study the performance and exhaust emissions characteristics with different speeds and blends at full load. The engine speeds were chosen to be 1100 to 1400 rpm at an interval of 100 rpm. Also, fuel blends such as diesel (as a base), B5, and B10 biodiesel were selected for engine testing. To model a engine, we should have the dimensions of the engine, input air collection, output gases collection, the amount of sprinkled fuel, valves properties, combustion, and some of the estimates corresponding to the cylinder’s thermodynamic parameters when opening the output and input gate and to exchange the heat inside the cylinder as the input data. The model mainly consisted of an air cleaner, intake valve, exhaust valve, intake and exhaust port, injection nozzle, engine cylinder, and engine. Engine cylinder’s intake and exhaust ports are modeled geometrically with pipes. Before this investigation was carried out, a validation model for evaluation was done by experimental and simulation data. The validation results showed that the software model error is acceptable.Results and DiscussionThe engine performance and emissions were evaluated in terms of engine torque, specific fuel consumption, NOx, and CO emission at different engine speeds and fuels at full load. The results showed that with increasing the engine speeds, torque increased. On the other hand, the maximum engine torque for the diesel engine is slightly lower than the biodiesel-blended that increased by 4.4% because of the higher density and viscosity of biodiesel than diesel. Specific Fuel Consumption (SFC) is a measure of the fuel efficiency of any prime mover that burns fuel and produces rotation, or shaft, power. The results indicated that by increasing engine speeds, the SFC increased. A fuel with a lower heating value should be injected with more mass into the engine. This will increase the SFC. So, the maximum engine SFC for the diesel engine is more than the biodiesel-blended that decreased by 4.45% because of better fuel combustion and more power generation of biodiesel than diesel. The only nitrogen oxide that can be formed in an engine combustion temperature is nitrogen monoxide (NO). This pollutant factor can be converted to nitrogen dioxide (NO2) over the time of exhaust gas. The results showed that with increasing the engine speeds, the NOX emissions decrease steadily and then increases, which is due to the high temperature in the cylinder. The viscosity and density of fuels have an effect on NOX emission, and because of the larger droplets of the fuel, it released NOX. The highest NOx emissions belong B10 biodiesel in 1400 rpm, due to the high oxygen content of this fuel and the lowest NOx emissions belong B10 biodiesel in 1300 rpm, due to the low density of the fuel compared to diesel. CO is a colorless and odorless gas, whose even very low concentrations are dangerous for humans and animals. The results showed that with increasing the engine speeds, the CO emission decreased and the minimum CO emission for diesel engine is more than the biodiesel-blended that decreased by 37.61% because of excess oxygen availability and complete combustion in biodiesel than diesel.ConclusionThe results of this study showed that the B10 blend in high engine speeds, generally had the best performance and emissions characteristics among the three fuels used in this study. Also, this investigation will assist in the development of WCO biodiesel as a viable sustainable fuel source through the use of a CFD model, optimized engine configuration, and technical report
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