386 research outputs found

    Analysis of Heat Transfer in the Material during Pulsed Laser-Metal Interaction by Using Kinetic Theory

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    Nowadays technological developments, the use of lasers in production is increasing and plays an important role due to low cost and high accuracy. The heat transfer, over the course of laser-metal interplay, has a great importance in metal forming. In this study, different types of materials were investigated in order to designate the temperature distributions inside material and on the material surface versus the thermodynamic properties of the material used and then the temperature distributions obtained from the analysis were compared each other. In addition, the heat transfer is occurring during the interaction of the laser power of 1.1010 W/m2 and 5.1010 W/m2 with laser power intensity in two main groups using different materials these are steel, nickel, tantalum and titanium, and numerical results are obtained using the finite-difference method. In the first step, a solution is obtained by electron kinetic theory according to the basic heat transfer. In the second step, since heat convection is formed after material has reached the melting point. Using electron kinetic theory model for convection solutions have been obtained. Moreover, the temperature distribution that occurs during the laser metal interaction was studied by variation of the time chart and the material depth. As a result of the study, material's surface at the correct temperature of liquid phase change material and increased depth in the direction perpendicular to the electro-kinetic theory approach is further demonstrated by the decrease in the first manner and then remains constant in exponential phase change temperature. In addition to this the analysis results, the substrate temperature increases, the change in phase in the material becomes smaller and smaller

    Role of stocking density of tilapia (Oreochromis aureus) on fish growth, water quality and tomato (Solanum lycopersicum) plant biomass in the aquaponic system

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    The present study reports the results of the production of Nile tilapia (Oreochromis aureus) and tomato (Solanum lycopersicum) in the classical aquaponic system (one-loop) with different fish density. The experiment as the first scientific aquaponics study in Turkey was conducted at the Ankara University, Faculty of Agriculture, using in-door, small-scale classical aquaponic systems. Ninety six tilapia juveniles (O. aureus) were stocked at different ratio; 25 kg/m3 (Group I), 35 kg/m3 (Group II) and 50 kg/m3 (Group III) and fed with 45% raw protein feed at the level of 2% body weight for 126 days. Fish density affected the fish growth parameters and the most densiest group showed the best results in terms of fish growth and feed efficiency. Water quality parameters measured fluctated during the experiment even the exceed of the optimal ranges for the fish. However, tilapia tolerated the changes of water quality. Total plant biomass was low with the various limiting factors including insufficient lighting of in-door aquaponics system and low level of water potassium. The results of this study clearly illustrate the fish stocking rate has an impact on total biomass in the aquaponics and in one-loop aquaponics the water quality fluctation is the main challenging factor

    Improved chemotaxis differential evolution optimization algorithm

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    The social foraging behavior of Escherichia coli has recently received great attention and it has been employed to solve complex search optimization problems.This paper presents a modified bacterial foraging optimization BFO algorithm, ICDEOA (Improved Chemotaxis Differential Evolution Optimization Algorithm), to cope with premature convergence of reproduction operator.In ICDEOA, reproduction operator of BFOA is replaced with probabilistic reposition operator to enhance the intensification and the diversification of the search space.ICDEOA was compared with state-of-the-art DE and non-DE variants on 7 numerical functions of the 2014 Congress on Evolutionary Computation (CEC 2014). Simulation results of CEC 2014 benchmark functions reveal that ICDEOA performs better than that of competitors in terms of the quality of the final solution for high dimensional problems

    Use of a Global Positioning System (GPS) to Manage Extensive Sheep Farming and Pasture Land

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    The terrestrial climate is not sufficient to produce enough food to meet the roughage needs of the animals benefiting from the pasture lands because of excessive and early grazing of those areas. Plant growth is adversely affected in pastures that are not uniformly grazed. Tracking animals using the Global Positioning System (GPS) is a very important factor in determining the uniform distribution of grazing animals in a pasture, increasing the utilization rate of the pasture, and saving costs and time. With GPS tracking systems, establishing more effective pasture-use systems by monitoring the feeding regimes of small animals, the status of feed in the pasture, and the grazing behavior of the animals would be possible. The present study aimed to investigate the use of GPS for pasture and herd management in Turkey in addition to using the traditional techniques.In the present study conducted in the village of Köseyusuflu in Yozgat Province in May 2017, 2018, and 2019, grazing benefits that were determined from the pasture containing two Akkaraman sheep herds were recorded using GPS tracking devices. The results suggested that the area covered with vegetation along the sheep’s spring grazing routes varied between 43.6 and 62.9%, the ratio of legumes in the pasture grass in the low grazing areas was between 0.50 and 4.10%, and the grass species were between 12.75 and 44.50%. We determined that the sheep in herd A traveled between 7.6 and 9.9 km, while the sheep in herd B traveled between 4.7 and 5.7 km daily, and the two herds grazed an average of between 122 and 254 daa

    Adsorption of Nitrogen Dioxide (NO2) for Different Gas Concentrations, Temperatures and Relative Humidities by using Activated Carbon Filter: An Experimental Study

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    Noxious gases can be reduced through activated carbon; nevertheless, this process is very complex due to the changing parameters. Nitrogen dioxides take place in the so-called reactive gases. The nitrogen dioxide concentration existing in the environment can be harmful, in particular for asthmatics and it also has the potential to bring about other serious diseases. For instance, interior diseases are often caused by nitrogen oxide gases. Through this study, we have observed the nitrogen dioxide adsorption on the active carbon for varying air temperatures, gas concentrations and air relative humidities. In this context, it has been examined the effect of all three parameters. While conducting this project, we have used parameters between 1ppm and 30ppm (for NO2 concentration), 23°C and 33°C (for air temperature), 30% and 90% (for air relative humidity). In order to understand this process, breakthrough curves of NO2evaluated from experiments have been used in the present study. Results show that the humidity has not a remarkable effect on the adsorption of NO2; however, increasing relative humidity causes to a decrease in the capacity of the activated carbon for NO2 adsorption. Additionally, NO2 adsorption is exothermic, therefore it increases the air temperature

    The morphological investigations on the heart and some vessels of bovine foetus between the 15th and 25th weeks of gestation

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    Background: The aim of this study was to define the morphological and morphometric development of the foetus heart obtained from the domestic cattle in the gestation period of 15–25 weeks. Materials and methods: For this purpose, a total of 30 hearts belonging to cattle foetuses (15 males, 15 females) were used. The ages of foetuses were calculated according to the forehead-to-tail length and examined in three different groups. After dissection; biometric, macroanatomic, morphometric and histological findings were obtained from the foetal hearts according to the groups. In addition, mean values of the morphometric findings were determined. Results: As a result of the study, it was found that with the advancing age the convexity of margo ventricularis dexter increased and margo ventricularis sinister transformed from a convex-concave shape to a flat shape. The heart-to-body weight ratio was determined as 0.08% for Group II female foetuses and 0.09% for all other groups. The heart heights for Groups I, II, and III females were identified as 26.21, 41.00, and 46.27 mm, respectively, and for the males 26.45, 34.89, and 47.15 mm, respectively. In the statistical analysis, it was determined that all the morphometric values measured from the heart correlated significantly with the forehead-to-tail length. Conclusions: The data obtained as a result of the study is thought to help understand the morphological and morphometrical development of the heart, pioneer the attempts to create a foetal cattle heart model, and thus help in the diagnosis of the foetal heart pathologies.acieleck

    Spectra disentangling applied to the Hyades binary Theta^2 Tau AB: new orbit, orbital parallax and component properties

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    Theta^2 Tauri is a detached and single-lined interferometric-spectroscopic binary as well as the most massive binary system of the Hyades cluster. The system revolves in an eccentric orbit with a periodicity of 140.7 days. The secondary has a similar temperature but is less evolved and fainter than the primary. It is also rotating more rapidly. Since the composite spectra are heavily blended, the direct extraction of radial velocities over the orbit of component B was hitherto unsuccessful. Using high-resolution spectroscopic data recently obtained with the Elodie (OHP, France) and Hermes (ORM, La Palma, Spain) spectrographs, and applying a spectra disentangling algorithm to three independent data sets including spectra from the Oak Ridge Observatory (USA), we derived an improved spectroscopic orbit and refined the solution by performing a combined astrometric-spectroscopic analysis based on the new spectroscopy and the long-baseline data from the Mark III optical interferometer. As a result, the velocity amplitude of the fainter component is obtained in a direct and objective way. Major progress based on this new determination includes an improved computation of the orbital parallax. Our mass ratio is in good agreement with the older estimates of Peterson et al. (1991, 1993), but the mass of the primary is 15-25% higher than the more recent estimates by Torres et al. (1997) and Armstrong et al. (2006). Due to the strategic position of the components in the turnoff region of the cluster, these new determinations imply stricter constraints for the age and the metallicity of the Hyades cluster. The location of component B can be explained by current evolutionary models, but the location of the more evolved component A is not trivially explained and requires a detailed abundance analysis of its disentangled spectrum.Comment: in press, 13 pages, 10 Postscript figures, 5 tables. Table~4 is available as online material. Keywords: astrometry - techniques: high angular resolution - stars: binaries: visual - stars: binaries: spectroscopic - stars: fundamental parameter

    Properties of 42 Solar-type Kepler Targets from the Asteroseismic Modeling Portal

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    Recently the number of main-sequence and subgiant stars exhibiting solar-like oscillations that are resolved into individual mode frequencies has increased dramatically. While only a few such data sets were available for detailed modeling just a decade ago, the Kepler mission has produced suitable observations for hundreds of new targets. This rapid expansion in observational capacity has been accompanied by a shift in analysis and modeling strategies to yield uniform sets of derived stellar properties more quickly and easily. We use previously published asteroseismic and spectroscopic data sets to provide a uniform analysis of 42 solar-type Kepler targets from the Asteroseismic Modeling Portal (AMP). We find that fitting the individual frequencies typically doubles the precision of the asteroseismic radius, mass and age compared to grid-based modeling of the global oscillation properties, and improves the precision of the radius and mass by about a factor of three over empirical scaling relations. We demonstrate the utility of the derived properties with several applications.Comment: 12 emulateapj pages, 9 figures, 1 online-only extended figure, 1 table, ApJS accepted (typo corrected in Eq.8
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