Статті в журналах: "Mixing losses"

1

Rose, M. G., and N. W. Harvey. "Turbomachinery Wakes: Differential Work and Mixing Losses." Journal of Turbomachinery 122, no. 1 (February 1, 1999): 68–77. http://dx.doi.org/10.1115/1.555429.

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In this paper the mixing of stator wakes in turbomachinery is considered. An extension is made to the existing model of Denton (1993, ASME J. Turbomach., 115, pp. 621–656) which addresses the effects of acceleration before mixing. Denton showed that if a total pressure wake was accelerated, mixing loss diminished, and vice versa. Here a total temperature wake is shown to exhibit a reverse trend. An attempt is also made to understand better the work transfer process between a stator wake and a rotor. The paper concentrates on axial turbines, but a brief look at compressors is included. It is argued that the free-stream work is not the same as the wake work, and the concept of “Differential Work” is introduced. A simple steady velocity triangle based model is proposed to give an estimate of the ratio of wake work to free-stream work (μ, see later). The model is compared to an unsteady CFD result to offer some verification of the assumptions. It is concluded that the rotodynamic work process tends to reduce total pressure wake depths in turbines and compressors and therefore mixing losses. The mixing loss due to total temperature wakes is less strongly affected by the differential work process. [S0889-504X(00)00801-1]

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2

Zdobnov, M. I., N. A. Lavrov, and V. V. Shishov. "Analysis of losses in the mixing section of the central air conditioner using the entropy-statistical method." MATEC Web of Conferences 324 (2020): 03005. http://dx.doi.org/10.1051/matecconf/202032403005.

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The article presents an entropy-statistical analysis of losses in the mixing section of a central air conditioner. The temperature and humidity of the outdoor and recirculating air were measured. The methodology for determining losses using the entropy-statistical method is presented in the work. The calculation of losses in the mixing section of the central air conditioner due to the mixing of air flows depending on the flow rate of the supply and recirculation air as well as due to hydraulic losses. A comparative analysis of the results is carried out and the distribution diagrams of the component losses are presented. Proposed conclusions regarding the way to reduce losses.

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3

Gao, J., Q. Zheng, G. Yue, and L. Sun. "Control of shroud leakage flows to reduce mixing losses in a shrouded axial turbine." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 5 (October 3, 2011): 1263–77. http://dx.doi.org/10.1177/0954406211423324.

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The losses caused by the leakage flows through the rotor tip clearance, and the mixing losses by the re-entering leakage into the main flow are considerable parts of the total losses in turbines. The main reason for the mixing losses is the different velocity components of main and leakage flows. This leads to shear stresses which cause increased turbulence and losses. This article presents a numerical investigation on three different configurations to control the leakage flows: (a) turning vanes are fixed onto the casing between the fins to turn the shroud leakage flow into the main flow direction in order to reduce the circumferential mixing losses; (b) honeycomb bands are inserted into the casing to weaken the leakage flow in the circumferential direction and reduce the circumferential mixing losses due to the special hexagon structure; and (c) downstream edge of the cavity is chamfered to reduce the radial velocity component of the leakage jet and the separation at the downstream edge, and also to reduce the streamwise mixing losses. A 1.5-stage axial turbine with high-aspect ratio blading was used in this study to investigate the sealing designs as mentioned. The flow simulation results of the three configurations were analysed and compared in this article.

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4

Kasumova, Rena J. "Four wave mixing and compensating losses in metamaterials." Superlattices and Microstructures 121 (September 2018): 86–91. http://dx.doi.org/10.1016/j.spmi.2018.07.013.

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5

Arbel, A., A. Shklyar, D. Hershgal, M. Barak, and M. Sokolov. "Ejector Irreversibility Characteristics." Journal of Fluids Engineering 125, no. 1 (January 1, 2003): 121–29. http://dx.doi.org/10.1115/1.1523067.

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The present study analyzes and characterizes the irreversibility of the ejector’s internal processes in an effort to improve the understanding of the making of its overall performance. The analysis presented is based on entropy production methodology. Since entropy production is equivalent to performance losses, minimizing entropy production could serve as a tool for performance optimization. The three main internal processes forming sources of ejector irreversibility are mixing, kinetic energy losses, and normal shock wave. Comparison of these with those of an ideal mixing process, an ideal turbine-compressor system and stagnation conditions (of the flow after mixing) provides the benchmarks against which the actual overall performance is measured. By identifying the sources of irreversibility, the analysis provides a diagnostic tool for performance improvements. While irreversibility due to mixing can be eliminated by appropriate choice of gas and/or inlet conditions and an appropriate adjustable throat can eliminate losses associated with normal shock wave–kinetic energy losses can only be reduced but not totally eliminated.

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6

Schobeiri, M. T., and K. Pappu. "Optimization of Trailing Edge Ejection Mixing Losses: A Theoretical and Experimental Study." Journal of Fluids Engineering 121, no. 1 (March 1, 1999): 118–25. http://dx.doi.org/10.1115/1.2821991.

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The aerodynamic effects of trailing edge ejection on mixing losses downstream of cooled gas turbine blades were experimentally investigated and compared with an already existing one-dimensional theory by Schobeiri (1989). The significant parameters determining the mixing losses and, therefore, the efficiency of cooled blades, are the ejection velocity ratio, the cooling mass flow ratio, the temperature ratio, the slot thickness ratio, and the ejection flow angle. To cover a broad range of representative turbine blade geometry and flow deflections, a General Electric power generation gas turbine blade with a high flow deflection and a NASA-turbine blade with intermediate flow deflection and different thickness distributions were experimentally investigated and compared with the existing theory. Comprehensive experimental investigations show that for the ejection velocity ratio μ = 1, the trailing edge ejection reduces the mixing losses downstream of the cooled gas turbine blade to a minimum, which is in agreement with the theory. For the given cooling mass flow ratios that are dictated by the heat transfer requirements, optimum slot thickness to trailing edge thickness ratios are found, which correspond to the minimum mixing loss coefficients. The results allow the turbine aerodynamicist to minimize the mixing losses and to increase the efficiency of cooled gas turbine blades.

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7

Moore, J., and R. Y. Adhye. "Secondary Flows and Losses Downstream of a Turbine Cascade." Journal of Engineering for Gas Turbines and Power 107, no. 4 (October 1, 1985): 961–68. http://dx.doi.org/10.1115/1.3239842.

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The loss mechanisms and the behavior of secondary flows downstream of a large scale, linear turbine cascade have been investigated experimentally. A five-blade replica of the cascade used by Langston et al. at United Technologies Research Center was used for the present tests. Detailed flow measurements, using five-hole and three-hole probes, were made at four different planes, one just upstream of the trailing edge and the rest downstream. The secondary flow field at each measurement plane was found to be dominated by a single large passage vortex, which decayed in strength because of the mixing occurring in the flow. More than one-third of the losses were found to occur downstream of the trailing edge. This rise in total pressure loss in the present tests was almost entirely explained by a corresponding dissipation of the secondary kinetic energy of the flow. A mixing analysis of the flow was done to predict the additional losses due to “mixing” until the flow became completely uniform.

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8

Llobet, J. R., R. J. Gollan, and I. H. Jahn. "Effect of scramjet inlet vortices on fuel plume elongation and mixing rate." Aeronautical Journal 123, no. 1265 (June 21, 2019): 1032–52. http://dx.doi.org/10.1017/aer.2019.45.

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ABSTRACTHypersonic air-breathing propulsion can improve cost and flexibility of Low Earth Orbit (LEO) satellite launch missions. However, at the high flight Mach numbers required for access-to-space, performance margins are extremely tight. Techniques to improve mixing efficiency can push this technology forward. However, these are required to produce a minimal increase in losses and heat loads to be viable. The use of inlet-generated vortices in scramjets for mixing enhancement was previously studied. These vortices interact with the injected fuel plume, stretching it and increasing its effective surface for mixing. Moreover, these vortices are intrinsic to the flowfield. Therefore, contrary to other methods, when using inlet vortices mixing is enhanced without producing additional heat loads or losses. This work studies the vortex-injection interaction through numerical RANS simulations. A non-dimensional variable defining the quality of the plume shape for mixing purposes is proposed. This parameter is used to assess the effect of vortex intensity and injector location on fuel plume shape. The results show the ability of inlet vortices to modify fuel plume shape significantly increasing fuel mixing rate with minimal impact on losses.

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9

Jackson, D. J., K. L. Lee, P. M. Ligrani, and P. D. Johnson. "Transonic Aerodynamic Losses Due to Turbine Airfoil, Suction Surface Film Cooling." Journal of Turbomachinery 122, no. 2 (February 1, 1999): 317–26. http://dx.doi.org/10.1115/1.555455.

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The effects of suction surface film cooling on aerodynamic losses are investigated using an experimental apparatus designed especially for this purpose. A symmetric airfoil with the same transonic Mach number distribution on both sides is employed. Mach numbers range from 0.4 to 1.24 and match values on the suction surface of airfoils from operating aeroengines. Film cooling holes are located on one side of the airfoil near the passage throat where the free-stream Mach number is nominally 1.07. Round cylindrical and conical diffused film cooling hole configurations are investigated with density ratios from 0.8 to 1.3 over a range of blowing ratios, momentum flux ratios, and Mach number ratios. Also included are discharge coefficients, local and integrated total pressure losses, downstream kinetic energy distributions, Mach number profiles, and a correlation for integral aerodynamic losses as they depend upon film cooling parameters. The contributions of mixing and shock waves to total pressure losses are separated and quantified. These results show that losses due to shock waves vary with blowing ratio as shock wave strength changes. Aerodynamic loss magnitudes due to mixing vary significantly with film cooling hole geometry, blowing ratio, Mach number ratio, and (in some situations) density ratio. Integrated mixing losses from round cylindrical holes are three times higher than from conical diffused holes, when compared at the same blowing ratio. Such differences depend upon mixing losses just downstream of the airfoil, as well as turbulent diffusion of streamwise momentum normal to the airfoil symmetry plane. [S0889-504X(00)02202-9]

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10

Schobeiri, T. "Optimum Trailing Edge Ejection for Cooled Gas Turbine Blades." Journal of Turbomachinery 111, no. 4 (October 1, 1989): 510–14. http://dx.doi.org/10.1115/1.3262301.

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The effect of trailing edge ejection on the flow downstream of a cooled gas turbine blade is investigated. Parameters that affect the mixing losses and therefore the efficiency of cooled blades are the ejection velocity ratio, the cooling mass flow ratio, the slot-width ratio, and the ejection angle. For ejection velocity ratio μ = 1, the trailing edge ejection reduces the mixing losses downstream to the cooled blade. For given cooling mass flow ratios, optimum slot-width/trailing edge ratios are found, which correspond to the minimum mixing loss coefficients.

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11

Morrison, Blair, Yanbing Zhang, Mattia Pagani, Benjamin Eggleton, and David Marpaung. "Four-wave mixing and nonlinear losses in thick silicon waveguides." Optics Letters 41, no. 11 (May 17, 2016): 2418. http://dx.doi.org/10.1364/ol.41.002418.

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12

Floryan, J. M., and Sahab Zandi. "Reduction of pressure losses and increase of mixing in laminar flows through channels with long-wavelength vibrations." Journal of Fluid Mechanics 864 (February 11, 2019): 670–707. http://dx.doi.org/10.1017/jfm.2019.21.

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Pressure losses and mixing in vibrating channels were analysed. The vibrations in the form of long-wavelength travelling waves were considered. Significant reduction of pressure losses can be achieved using sufficiently fast waves propagating downstream, while significant increase of such losses is generated by waves propagating upstream. The mechanisms responsible for pressure losses were identified and discussed. The interaction of the pressure field with the waves can create a force which assists the fluid movement. A similar force can be created by friction, but only under conditions leading to flow separation. An analysis of particle trajectories was carried out to determine the effect of vibrations on mixing. A significant transverse particle movement takes place, including particle trajectories with back loops. The downstream-propagating out-of-the phase waves provide a large reduction of pressure gradient and significant potential for mixing intensification. Analysis of energy requirements demonstrates that it is possible to identify waves which reduce power requirements, i.e. the cost of actuation is smaller than the energy savings associated with the reduction of pressure gradient. The fast forward moving waves provide an opportunity for the development of alternative propulsion methods which can be more efficient than methods based on the pressure difference.

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13

Young, J. B., and R. C. Wilcock. "Modeling the Air-Cooled Gas Turbine: Part 1—General Thermodynamics." Journal of Turbomachinery 124, no. 2 (April 1, 2002): 207–13. http://dx.doi.org/10.1115/1.1415037.

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This paper is Part I of a study concerned with developing a formal framework for modeling air-cooled gas turbine cycles and deals with basic thermodynamic issues. Such cycles involve gas mixtures with varying composition which must be modeled realistically. A possible approach is to define just two components, air and gas, the latter being the products of stoichiometric combustion of the fuel with air. If these components can be represented as ideal gases, the entropy increase due to compositional mixing, although a true exergy loss, can be ignored for the purpose of performance prediction. This provides considerable simplification. Consideration of three idealized simple cycles shows that the introduction of cooling with an associated thermal mixing loss does not necessarily result in a loss of cycle efficiency. This is no longer true when real gas properties and turbomachinery losses are included. The analysis clarifies the role of the cooling losses and shows the importance of assessing performance in the context of the complete cycle. There is a strong case for representing the cooling losses in terms of irreversible entropy production as this provides a formalized framework, clarifies the modeling difficulties, and aids physical interpretation. Results are presented that show the effects on performance of varying cooling flowrates and cooling losses. A comparison between simple and reheat cycles highlights the ro^le of the thermal mixing loss. Detailed modeling of the heat transfer and cooling losses is discussed in Part II of this paper.

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14

Cao, Lihua, Heyong Si, Jiaxin Wang, and Pan Li. "Effects of leakage vortex on aerodynamic performance and loss mechanism of steam turbine." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 233, no. 7 (February 20, 2019): 866–76. http://dx.doi.org/10.1177/0957650919831916.

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To avoid friction, a clearance between the rotor blade tip and the cylinder is needed in a steam turbine. As a result, the leakage flow is formed under the pressure difference which mixes with the main flow and causes the mixing loss. So, a numerical calculation was conducted based on a high-pressure 1.5-stage steam turbine with the tip labyrinth seal. The leakage vortex system and the mixing progress at different tip clearances were analyzed. The related leakage losses were calculated. The results show that the leakage flow will lead to the steam deflecting at the rotor exit and cause incidence loss. Furthermore, in the downstream stator, the leakage flow near the suction side with high radial velocity causes the deflection of the outflow angles. The main influence region of leakage flow is distributed above 75% of blade height, whereas the most intense region is distributed at approximately 95% of blade height. It is found that the mixing loss is related to the size of the backflow vortex. The related leakage losses increase with tip clearance, in which the mixing loss is the major part and the mass-averaged entropy mixing loss coefficient is 7–11%.

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15

Vinogradov, Viacheslav A., Yurii M. Shikhman, and Corin Segal. "A Review of Fuel Pre-injection in Supersonic, Chemically Reacting Flows." Applied Mechanics Reviews 60, no. 4 (July 1, 2007): 139–48. http://dx.doi.org/10.1115/1.2750346.

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Developing an efficient, supersonic combustion-based, air breathing propulsion cycle operating above Mach 3.5, especially when conventional hydrocarbon fuels are sought and particularly when liquid fuels are preferred to increase density, requires mostly effective mechanisms to improve mixing efficiency. One way to extend the time available for mixing is to inject part of the fuel upstream of the vehicle’s combustion chamber. Injection from the wall remains one of the most challenging problems in supersonic aerodynamics, including the requirement to minimize impulse losses, improve fuel-air mixing, reduce inlet∕combustor interactions, and promote flame stability. This article presents a review of studies involving liquid and, in selected cases, gaseous fuel injected in supersonic inlets or in combustor’s insulators. In all these studies, the fuel was injected from a wall in a wake of thin swept pylons at low dynamic pressure ratios (qjet∕qair=0.6–1.5), including individual pylon∕injector geometries and combinations in the inlet and combustor’s isolator, a variety of injection conditions, different injectants, and evaluated their effects on fuel plume spray, impulse losses, and mixing efficiency. This review article cites 47 references.

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16

Mohammad, Abdulqahar M. "Effect of Operating Condition on the Losses in Fermenter." Tikrit Journal of Engineering Sciences 21, no. 1 (June 11, 2013): 45–52. http://dx.doi.org/10.25130/tjes.21.1.10.

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The influence of the operating conditions on the losses rates in controlled batchand continuous fermentation reactor has been studied. In which 120 l pilot fermenterreactor used to produce acetic acid from ethanol at standard condition. The results show,the increasing of 1 ºC of mixture temperature, increasing of 1 m3/h of the aeration flowrate or increasing the mixing speed to 1 rpm leading to increase the losses rates to (1.22,0.92, 0.94 ml/l) respectively.

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17

Desikan, S. L. N., and J. Kurian. "Experimental investigation of the role of struts in high speed mixing." Aeronautical Journal 117, no. 1188 (February 2013): 193–211. http://dx.doi.org/10.1017/s0001924000007946.

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AbstractThis paper presents the experimental results of the role of struts in supersonic mixing. Experiments were carried out with novel strut configurations to show their capabilities on mixing with reasonable total pressure losses. The performances were compared with the Baseline Strut configurations (BSPI and BSNI). The analysis presented includes the mixing quantifications using Mie scattering signature, flow field visualisation, measurement of wall static pressure and the total pressure loss calculations. The results clearly demonstrated that the proposed strut configurations achieved increased mixing (7-8%) compared to BSPI with increase in total pressure loss (2%). On the other hand, when compared with BSNI, the mixing performance was found to be decreased by 6% with reduced total pressure loss (12%).

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18

Chwedeńczuk, J., M. Trippenbach, and K. Rzazewski. "Elastic scattering losses in the four-wave mixing of Bose–Einstein condensates." Journal of Physics B: Atomic, Molecular and Optical Physics 37, no. 24 (December 7, 2004): L391—L398. http://dx.doi.org/10.1088/0953-4075/37/24/l01.

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19

Wei, Tianxiang, Shuchao Lv, and Jietai Jing. "Effect of losses on multipartite entanglement from cascaded four-wave mixing processes." Journal of the Optical Society of America B 35, no. 11 (October 18, 2018): 2806. http://dx.doi.org/10.1364/josab.35.002806.

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20

Wang, Zhaozhi, Tiequan Zhang, Chin Sheng Tan, Lulin Xue, Melissa Bukovsky, and Zhiming Qi. "Modeling tillage and manure application on soil phosphorous loss under climate change." Nutrient Cycling in Agroecosystems 122, no. 2 (February 26, 2022): 219–39. http://dx.doi.org/10.1007/s10705-022-10192-7.

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AbstractPhosphorus (P) losses from non-point sources into receiving water bodies play a significant role in eutrophication. Given their failure to adequately control eutrophication in the Lake Erie, conservation recommendations for agricultural watersheds should be reconsidered, particularly under climate change. Using the Environmental Policy Integrated Climate model, the potential impacts on crop yield, surface runoff, tile drainage, and relevant dissolved reactive phosphorus (DRP) losses from manure-amended corn-soybean rotation plots in the Lake Erie basin were estimated for six tillage methods with different mixing efficiencies and manure broadcast application. These were investigated under twelve different regional and global future climate simulations. Tillage alone proved to have only a minor impact on mean corn yield (± 2%). Climate change led to large uncertainties under the single tillage treatment. As a result of the combined effects of biogeochemical processes (e.g., supply) and hydrological (e.g., transport), strong negative relationships (R2 = 0.98) were found between tillage mixing efficiency and DRP loss in surface runoff, tile drainage, and total DRP loss. The impacts of combined manure application (broadcast) and tillage on crop yield and flow volume were similar as those of tillage alone. With respect to total DRP losses, the effects of labile P content change outweighed those of surface runoff or tile drainage change (hydrologic). This resulted in a change in total DRP losses ranging from − 60% to + 151%, with being closely correlated with decreasing tillage mixing efficiency (R2 = 0.94) from moldboard to no-till. Therefore, rotational tillage should be considered for DRP loss reduction and energy saving.

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21

Christianson, C. B., G. Carmona, M. O. Klein, and R. G. Howard. "Impact on ammonia volatilization losses of mixing KCl of high pH with urea." Fertilizer Research 40, no. 2 (1995): 89–92. http://dx.doi.org/10.1007/bf00750092.

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22

Pfau, A., A. I. Kalfas, and R. S. Abhari. "Making Use of Labyrinth Interaction Flow." Journal of Turbomachinery 129, no. 1 (March 1, 2004): 164–74. http://dx.doi.org/10.1115/1.2218571.

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It is the aim of this publication to attract the designers attention to the end wall flow interactions of shrouded high pressure turbines. One of the key issues for designing better turbines is the understanding of the flow interactions set up by the presence of labyrinth seals. Those interaction flows are carefully examined in this publication using the control volume analysis and the radial equilibrium of forces acting on streamlines. The consequences on secondary flow development and mixing losses are discussed and quantified. Out of this insight, design recommendations are derived, which attempt to make use of the nature of the labyrinth interaction flow. The open labyrinth cavities are classified in a systematic way. The aim of this approach is to work out the characteristic differences between hub and tip cavities and those having a leakage jet or sucking main flow fluid into the labyrinth. The influence on the main flow is discussed in terms of the incidence flow angle of downstream blade rows and the associated loss production mechanisms. The design strategies presented in this paper follow two paths: (a) Optimization of the mixing losses of the leakage jets at hub and tip is estimated to result in an efficiency increase of up to 0.2%. (b) The nonaxisymmetric shaping of the labyrinth interaction flow path aims at the secondary flow control in downstream blade rows. This approach might contribute in the same magnitude of order as reduction in the mixing losses.

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23

Flamang, P., and R. Sierens. "Study of the Steady-State Flow Pattern in a Multipulse Converter by LDA." Journal of Engineering for Gas Turbines and Power 110, no. 3 (July 1, 1988): 515–22. http://dx.doi.org/10.1115/1.3240165.

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This paper describes pressure and velocity measurements on a multipulse converter under steady-state conditions. Pressure loss coefficients were measured on this four-entry pulse converter system for a large number of flow configurations. Three-dimensional velocity measurements were done (with Laser-Doppler anemometry) for several flow configurations and at different cross sections in the converter. The normal flow situation (incoming flow at the four entries) and back flow situations were examined. For each cross section the axial velocity profiles, the secondary flow patterns, and the turbulent velocities are presented. From the pressure measurements mixing losses are derived. These are compared with the results of a one-dimensional calculation, which is based on the impulse law for incompressible flow. Taking into account the velocity measurements, this simplified model gives a remarkable agreement with the measured mixing losses.

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24

Friedrichs, S., H. P. Hodson, and W. N. Dawes. "Aerodynamic Aspects of Endwall Film-Cooling." Journal of Turbomachinery 119, no. 4 (October 1, 1997): 786–93. http://dx.doi.org/10.1115/1.2841189.

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This paper describes an investigation of the aerodynamic aspects of endwall film-cooling, in which the flow field downstream of a large-scale low-speed linear turbine cascade has been measured. The integrated losses and locations of secondary flow features with and without endwall film-cooling have been determined for variations of both the coolant supply pressure and injection location. Together with previous measurements of adiabatic film-cooling effectiveness and surface-flow visualization, these results reveal the nature of the interactions between the ejected coolant and the flow in the blade passage. Measured hole massflows and a constant static pressure mixing analysis, together with the measured losses, allow the decomposition of the losses into three distinct entropy generation mechanisms: loss generation within the hole, loss generation due to the mixing of the coolant with the mainstream, and change in secondary loss generation in the blade passage. Results show that the loss generation within the coolant holes is substantial and that ejection into regions of low static pressure increases the loss per unit coolant massflow. Ejection upstream of the three-dimensional separation lines on the endwall changes secondary flow and reduces its associated losses. The results show that it is necessary to take the three-dimensional nature of the endwall flow into account in the design of endwall film-cooling configurations.

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25

Hernández, I., J. M. Cañedo, J. C. Olivares-Galván, and Pavlos S. Georgilakis. "Electromagnetic Analysis and Comparison of Conventional-Wound Cores and Octagonal-Wound Cores of Distribution Transformers." Materials Science Forum 670 (December 2010): 477–86. http://dx.doi.org/10.4028/www.scientific.net/msf.670.477.

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This paper presents comparative results of an electromagnetic study performed in two different wound core transformer configurations in order to know the best configuration that reduce excitation current and core losses. The results show that octagonal wound-core (OWC) reduces the excitation current and eddy-current losses with respect conventional-wound core (CWC). The results were obtained applying 2D and 3D FEM simulations, taking into account the non-linear properties of the core. In the last part of this paper, several grades of grain oriented electrical steels and the combination of them are analyzed to find the best mixing percentage to reduce eddy-current losses and excitation current.

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26

Chen, L. D., and S. L. Dixon. "Growth of Secondary Flow Losses Downstream of a Turbine Blade Cascade." Journal of Engineering for Gas Turbines and Power 108, no. 2 (April 1, 1986): 270–76. http://dx.doi.org/10.1115/1.3239899.

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Endwall total pressure losses downstream of a low-speed turbine cascade have been measured at several planes in order to determine the changes in secondary flow loss coefficients and the growth of the mixing loss with distance downstream. The results obtained are compared with various published secondary flow loss correlations in an attempt to explain some of the anomalies which presently exist. The paper includes some new correlations including one for the important gross secondary loss coefficient YSG with loading and aspect ratio parameters as well as the upstream boundary layer parameters.

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27

Mahammedi, Abdelkader, Naas Toufik Tayeb, Kwang-Yong Kim, and Shakhawat Hossain. "Mixing Enhancement of Non-Newtonian Shear-Thinning Fluid for a Kenics Micromixer." Micromachines 12, no. 12 (November 30, 2021): 1494. http://dx.doi.org/10.3390/mi12121494.

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In this work, a numerical investigation was analyzed to exhibit the mixing behaviors of non-Newtonian shear-thinning fluids in Kenics micromixers. The numerical analysis was performed using the computational fluid dynamic (CFD) tool to solve 3D Navier-Stokes equations with the species transport equations. The efficiency of mixing is estimated by the calculation of the mixing index for different cases of Reynolds number. The geometry of micro Kenics collected with a series of six helical elements twisted 180° and arranged alternately to achieve the higher level of chaotic mixing, inside a pipe with a Y-inlet. Under a wide range of Reynolds numbers between 0.1 to 500 and the carboxymethyl cellulose (CMC) solutions with power-law indices among 1 to 0.49, the micro-Kenics proves high mixing Performances at low and high Reynolds number. Moreover the pressure losses of the shear-thinning fluids for different Reynolds numbers was validated and represented.

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28

Perrey-Debain, Emmanuel, and I. David Abrahams. "TE Mode Mixing Dynamics in Curved Multimode Optical Waveguides." Communications in Computational Physics 11, no. 2 (February 2012): 525–40. http://dx.doi.org/10.4208/cicp.211209.200710s.

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AbstractPropagation of light through curved graded index optical waveguides supporting an arbitrary high number of modes is investigated. The discussion is restricted to optical wave fields which are well confined within the core region and losses through radiation are neglected. Using coupled mode theory formalism, two new forms for the propagation kernel for the transverse electric (TE) wave as it travels along a curved two-dimensional waveguide are presented. One form, involving the notion of “bend” modes, is shown to be attractive from a computational point of view as it allows an efficient numerical evaluation of the optical field for sharply bent waveguides.

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29

Mee, D. J., N. C. Baines, M. L. G. Oldfield, and T. E. Dickens. "An Examination of the Contributions to Loss on a Transonic Turbine Blade in Cascade." Journal of Turbomachinery 114, no. 1 (January 1, 1992): 155–62. http://dx.doi.org/10.1115/1.2927979.

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Experiments to measure losses of a linear cascade of transonic turbine blades are reported. Detailed measurements of the boundary layer at the rear of the suction surface of a blade and examination of wake traverse data enable the individual components of boundary layer, shock and mixing loss to be determined. Results indicate that each component contributes significantly to the overall loss in different Mach number regimes. Traverses in the near wake of the blade indicate the way in which the wake develops and facilitate examination of the development of the mixing loss.

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30

SUGAWARA, Toru. "Experimental techniques to minimize Fe and Na losses in one atmosphere gas mixing furnace." JOURNAL OF MINERALOGY, PETROLOGY AND ECONOMIC GEOLOGY 94, no. 11 (1999): 425–41. http://dx.doi.org/10.2465/ganko.94.425.

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31

Victor Zerbes, Mihai, and Liliana Georgeta Popescu. "Study on improving silicone losses in the process of mixing components of soldering machines." MATEC Web of Conferences 184 (2018): 04021. http://dx.doi.org/10.1051/matecconf/201818404021.

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The paper presents a summary of the steps of the 6 Sigma methodology applied in the gluing section within an automotive company form Sibiu, Romania. We describe the synthesis of each step of the DMAIC model, a well-known model in the application of the 6 Sigma methodology. In the last chapter, we outline some general conclusions regarding the use of the 6 Sigma methodology presenting the benefits both within the automotive organization from Sibiu and its general use by industrial organizations.

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32

Popov, Alexander K., Sergey A. Myslivets, Thomas F. George, and Vladimir M. Shalaev. "Four-wave mixing, quantum control, and compensating losses in doped negative-index photonic metamaterials." Optics Letters 32, no. 20 (October 12, 2007): 3044. http://dx.doi.org/10.1364/ol.32.003044.

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33

Kantemirov, V. D., R. S. Titov, A. V. Timohin, and A. M. Jakovlev. "Improvement of methods of accounting for increased losses and dilution of minerals during production." Mining informational and analytical bulletin, no. 3-1 (March 20, 2020): 453–64. http://dx.doi.org/10.25018/0236-1493-2020-31-0-453-464.

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The article describes the methodological approaches to accounting and valuation losses of minerals during open development of deposits with complex mining and geological conditions. As an example, analyzes indicators of losses of minerals during the development phase of plot Kostonaiskogo Chanvinskogo deposits of limestone used for the production of caustic soda. The installed actual level losses exceeding 30% of the total production volume of raw materials. The given reasons of increased losses of limestone in comparison with in the project losses. Installed that with a detailed exploration of the array of limestone was not identified zone karst and zone with high clay content lying in the form of “lived” in zones of high fracturing. In the result of blasting is the mixing of karst explode, clogged areas with pure limestone, its pollution to exceed the allowable values, which leads to loss of balance reserves of minerals during extraction. The article gives recommendations for calculating the level of losses during the when developing complex faces, which are characterized by intermittency breed productive layer of limestone and karst zones.

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MATHEOU, GEORGIOS, ARISTIDES M. BONANOS, CARLOS PANTANO, and PAUL E. DIMOTAKIS. "Large-eddy simulation of mixing in a recirculating shear flow." Journal of Fluid Mechanics 646 (March 8, 2010): 375–414. http://dx.doi.org/10.1017/s0022112009992965.

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The flow field and mixing in an expansion-ramp geometry is studied using large-eddy simulation (LES) with subgrid scale (SGS) modelling. The expansion-ramp geometry was developed to investigate enhanced mixing and flameholding characteristics while maintaining low total-pressure losses. Passive mixing was considered without taking into account the effects of chemical reactions and heat release, an approximation that is adequate for experiments conducted in parallel. The primary objective of the current work is to validate the LES–SGS closure in the case of passive turbulent mixing in a complex configuration and, if successful, to rely on numerical simulation results for flow details unavailable via experiment. Total (resolved-scale plus subgrid contribution) probability density functions (p.d.f.s) of the mixture fraction are estimated using a presumed beta-distribution model for the subgrid field. Flow and mixing statistics are in good agreement with the experimental measurements, indicating that the mixing on a molecular scale is correctly predicted by the LES–SGS model. Finally, statistics are shown to be resolution-independent by computing the flow for three resolutions, at twice and four times the resolution of the coarsest simulation.

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35

Harrison, S. "The Influence of Blade Lean on Turbine Losses." Journal of Turbomachinery 114, no. 1 (January 1, 1992): 184–90. http://dx.doi.org/10.1115/1.2927982.

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Three linear cascades of highly loaded, low-aspect-ratio turbine blades have been tested in order to investigate the mechanisms by which blade lean (dihedral) influences loss generation. The blades in all three cascades have the same section but they are stacked perpendicular to the end wall in the first cascade, on a straight line inclined at 20 deg from perpendicular in the second, and on a circular arc inclined at 30 deg from perpendicular at each end in the third cascade. Lean has a marked effect upon blade loading, on the distribution of loss generation, and on the state of boundary layers on the blade suction surfaces and the endwalls, but its effect upon overall loss coefficient was found to be minimal. It was found, however, that compound lean reduced the downstream mixing losses, and reasons for this are proposed. Compound lean also has the beneficial effect of substantially reducing spanwise variations of mean exit flow angle. In a turbine this would be likely to reduce losses in the downstream blade row as well as making matching easier and improving off-design performance.

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36

Li, Guo Ping, Ke Ke Gao, Ke Yang, and Yong Hui Xie. "Full 3-D Unsteady Numerical Simulation of Control Stage in Partial Admission Turbine." Applied Mechanics and Materials 741 (March 2015): 509–12. http://dx.doi.org/10.4028/www.scientific.net/amm.741.509.

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The unsteady flow parameters in control stage of partial admission are analyzed in details with full 3-D numerical simulation. The full annulus structure of air turbine in partial admission is modeled due to the unsymmetrical geometry. The partial admission is accomplished through the inlet blocked using segmental arc. The unsteady surface pressure changes of eight blades in the transition regions which demonstrate the power output ability are presented. That the entropy rise associated with the losses at different cross mainly caused by mixing losses and flow separation in partial admission is analyzed to estimate the efficiency distribution.

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37

Oettinger, Marcel, Dajan Mimic, Michael Henke, Oleg Schmunk, and Jorg Seume. "Loss Assessment of the Axial-Gap Size Effect in a Low-Pressure Turbine." Journal of the Global Power and Propulsion Society 5 (January 26, 2021): 1–14. http://dx.doi.org/10.33737/jgpps/127834.

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The aim of this work is the decomposition, quantification, and analysis of losses related to the axial-gap size effect. Both experimental data and unsteady RANS calculations are investigated for axial gaps equal to 20%, 50% and 80% of the stator axial chord. A framework for identifying sources of loss typical in turbomachinery is derived and utilized for the low-pressure turbine presented. The analysis focuses on the dependency of these losses on the axial-gap variation. It is found that two-dimensional profile losses increase for smaller gaps due to higher wake-mixing losses and unsteady wake-blade interaction. Losses in the end-wall regions, however, decrease for smaller gaps. The total system efficiency can be described by a superposition of individual loss contributions, the optimum of which is found for the smallest gap investigated. It is concluded that these loss contributions are characteristic for the medium aspect-ratio airfoils and operating conditions investigated. This establishes a deeper physical understanding for future investigations into the axial-gap size effect and its interdependency with other design parameters.

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38

ROMANKO, Elena, Ivan PYTALEV, Elena BOBYLEVA, and Maria KOLKOVA. "Losses and drying normalization with a level-chamber development system with following laying." Sustainable Development of Mountain Territories 14, no. 1 (March 30, 2022): 126–33. http://dx.doi.org/10.21177/1998-4502-2021-13-4-126-133.

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Ensuring the sustainable development of mining territories is impossible without the rational use of natural resources – minerals during their extraction and primary processing. So, at the stage of mining operations, it is necessary to establish the normative value of losses and dilution of minerals. This value is determined taking into account mining and geological, technological, economic, organizational factors. The normative value of losses and dilution ensures the maximum possible economic effect from the applied geotechnology and primary processing of recoverable reserves. In addition, in order to implement full-fledged rationing, it is necessary to identify the main types of losses and dilution and establish the causes of their formation. The researchers found that the normalization of recovery indicators is possible in the case of searching for the level of losses and dilution at the contact of the deposit, that is, when these indicators are interdependent. For the conditions of most deposits with almost any method and system of development, this is the only type of normalized losses and dilution. The only exceptions are underground mining systems with the collapse of ore and host rocks. All other extraction indicators are determined analytically, experimentally, statistically, by direct measurement. For the conditions of development of the Novo-Uchalinsky deposit by underground geotechnology, the main types of extraction indicators are identified, their causes are established, recommendations are given for determining their magnitude and rationing. Thus, losses in the array and in the beaten form are highlighted, such as losses due to the complexity of the contact and in the corners of the camera, losses on the bottom of the camera and in the baseboards. Dilution occurs in the following types – from the complexity of contact, vaulting in the roof of the chamber, laying on the side of neighboring chambers, from mixing rock in rock dykes. Rationing is carried out by losses and dilution due to the complexity of the contact, in addition, it is possible to normalize dilution by laying on the side of neighboring chambers, since it is possible to establish the optimal contour of the projected chamber on contact with neighboring laid ones. Losses in the corners of the chamber, “in the baseboards”, dilution from vaulting in the roof of the chamber are determined analytically; losses on the bottom of the chamber, dilution by laying from neighboring chambers – experimentally; by direct measurement by geophysical methods, the parameters of the dikes of empty rocks are determined to establish the amount of dilution from mixing the rock in the rock dikes. The actual level of losses and dilution of ore after the mining of the dredging unit is provided equal to the standard with strict execution of the development system and technology of the main production processes.

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39

Moses, A. J., and S. Hamadeh. "Effects of mixing materials on losses and cost of operation of three‐phase transformer cores." Journal of Applied Physics 64, no. 10 (November 15, 1988): 5379–81. http://dx.doi.org/10.1063/1.342376.

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40

Xu, Jianguo, and Rakesh Agrawal. "Gas separation membrane cascades I. One-compressor cascades with minimal exergy losses due to mixing." Journal of Membrane Science 112, no. 2 (April 1996): 115–28. http://dx.doi.org/10.1016/0376-7388(95)00272-3.

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41

SASAKI, Souichi, Yoshio KODAMA, and Makoto HATAKEYAMA. "Influence of the Mixing Losses on the Aerodynamic Characteristics of a Multi-Blade Sirocco Fan." Transactions of the Japan Society of Mechanical Engineers Series B 71, no. 701 (2005): 72–79. http://dx.doi.org/10.1299/kikaib.71.72.

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42

Guedri, Abdessalam, Kawthar Yahya, Noureddine Hamdi, Oscar Baeza-Urrea, Jean-Frank Wagner, and Mohamed Faouzi Zagrarni. "Properties Evaluation of Composite Materials Based on Gypsum Plaster and Posidonia Oceanica Fibers." Buildings 13, no. 1 (January 9, 2023): 177. http://dx.doi.org/10.3390/buildings13010177.

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Estimating the amount of material without significant losses at the end of hybrid casting is a problem addressed in this study. To minimize manufacturing costs and improve the accuracy of results, a correction factor (CF) was used in the formula to estimate the volume percent of the material in order to reduce material losses during the sample manufacturing stage, allowing for greater confidence between the approved blending plan and the results obtained. In this context, three material mixing schemes of different sizes and shapes (gypsum plaster, sand (0/2), gravel (2/4), and Posidonia oceanica fibers (PO)) were created to verify the efficiency of CF and more precisely study the physico-mechanical effects on the samples. The results show that the use of a CF can reduce mixing loss to almost 0%. The optimal compressive strength of the sample (S1B) with the lowest mixing loss was 7.50 MPa. Under optimal conditions, the addition of PO improves mix volume percent correction (negligible), flexural strength (5.45%), density (18%), and porosity (3.70%) compared with S1B. On the other hand, the addition of PO thermo-chemical treatment by NaOH increases the compressive strength (3.97%) compared with PO due to the removal of impurities on the fiber surface, as shown by scanning electron microscopy. We then determined the optimal mixture ratio(PO divided by a mixture of plaster, sand, and gravel), which equals 0.0321 because Tunisian gypsum contains small amounts of bassanite and calcite, as shown by the X-ray diffraction results.

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43

Mori, Kanji, Motohiko Kusakabe, A. Baha Balantekin, Toshitaka Kajino, and Michael A. Famiano. "Enhancement of Lithium in Red Clump Stars by Neutrino Magnetic Moments." EPJ Web of Conferences 260 (2022): 11016. http://dx.doi.org/10.1051/epjconf/202226011016.

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A recent spectroscopic survey has shown that the lithium abundances in low-mass red-clump stars are higher than theoretical prediction. Motivated by their finding, we implemented effects of additional energy losses induced by neutrino magnetic moments on stellar evolution models. It is found that the lithium abundances in red giants increase because the finite magnetic moments of neutrinos enhance the efficiency of deep mixing and 7Be is conveyed from the hydrogen burning shell to the convective envelope. The results motivate further studies on the effects of non-standard energy losses on the surface compositions of low-mass red giants and red-clump stars.

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44

Berry, Helen D., Thomas F. Mumford, Bart Christiaen, Pete Dowty, Max Calloway, Lisa Ferrier, Eric E. Grossman, and Nathan R. VanArendonk. "Long-term changes in kelp forests in an inner basin of the Salish Sea." PLOS ONE 16, no. 2 (February 17, 2021): e0229703. http://dx.doi.org/10.1371/journal.pone.0229703.

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Kelp forests form an important biogenic habitat that responds to natural and human drivers. Global concerns exist about threats to kelp forests, yet long-term information is limited and research suggests that trends are geographically distinct. We examined distribution of the bull kelp Nereocystis luetkeana over 145 years in South Puget Sound (SPS), a semi-protected inner basin in a fjord estuary complex in the northeast Pacific Ocean. We synthesized 48 historical and modern Nereocystis surveys and examined presence/absence within 1-km segments along 452 km of shoreline. Compared to the earliest baseline in 1878, Nereocystis extent in 2017 decreased 63%, with individual sub-basins showing up to 96% loss. Losses have persisted for decades, across a range of climate conditions. In recent decades, Nereocystis predominantly occurred along shorelines with intense currents and mixing, where temperature and nutrient concentrations did not reach thresholds for impacts to Nereocystis performance, and high current speeds likely excluded grazers. Losses predominated in areas with elevated temperature, lower nutrient concentrations, and relatively low current velocities. The pattern of long-term losses in SPS contrasts with stability in floating kelp abundance during the last century in an area of the Salish Sea with greater wave exposure and proximity to oceanic conditions. These findings support the hypothesis that kelp beds along wave-sheltered shorelines exhibit greater sensitivity to environmental stressors. Additionally, shorelines with strong currents and deep-water mixing may provide refugia within sheltered systems.

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45

Mathur, A., and A. N. Netravali. "Effect of plasma polymerization on tensile properties of Kevlar fiber." Advanced Composites Letters 3, no. 1 (January 1994): 096369359400300. http://dx.doi.org/10.1177/096369359400300102.

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The effects of plasma polymerization on the tensile properties of Kevlar 49 fiber has been investigated. Gaseous ammonia was mixed with ethylene to deposit a thin cross linked film containing reactive functional groups on the fiber surface. Results suggest that the plasma conditions such as power input and mixing ratios could be manipulated to minimize the tensile property losses of the fiber.

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46

Ames, F. E., and M. W. Plesniak. "The Influence of Large-Scale, High-Intensity Turbulence on Vane Aerodynamic Losses, Wake Growth, and the Exit Turbulence Parameters." Journal of Turbomachinery 119, no. 2 (April 1, 1997): 182–92. http://dx.doi.org/10.1115/1.2841100.

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An experimental research program was undertaken to examine the influence of large-scale high-intensity turbulence on vane exit losses, wake growth, and exit turbulence characteristics. The experiment was conducted in a four-vane linear cascade at an exit Reynolds number of 800,000 based on chord length and an exit Mach number of 0.27. Exit measurements were made for four inlet turbulence conditions including a low-turbulence case (Tu ≈ 1 percent), a grid-generated turbulence case (Tu ≈ 7.5. percent) and two levels of large-scale turbulence generated with a mock combustor (Tu ≈ 12 and 8 percent). Exit total pressure surveys were taken at two locations to quantify total pressure losses. The suction surface boundary layer was also traversed to determine losses due to boundary layer growth. Losses occurred in the core of the flow for the elevated turbulence cases. The elevated free-stream turbulence was found to have a significant effect on wake growth. Generally, the wakes subjected to elevated free-stream turbulence were broader and had smaller peak velocity deficits. Reynolds stress profiles exhibited asymmetry in peak amplitudes about the wake centerline, which are attributable to differences in the evolution of the boundary layers on the pressure and suction surfaces of the vanes. The overall level of turbulence and dissipation inside the wakes and in the free stream was determined to document the rotor inlet boundary conditions. This is useful information for assessing rotor heat transfer and aerodynamics. Eddy diffusivities and mixing lengths were estimated using X-wire measurements of turbulent shear stress. The free-stream turbulence was found to strongly affect eddy diffusivities, and thus wake mixing. At the last measuring position, the average eddy diffusivity in the wake of the high-turbulence close combustor configuration (Tu ≈ 12) was three times that of the low turbulence wake.

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47

Gao, Jie, Ming Wei, Yunning Liu, Qun Zheng, and Ping Dong. "Experimental and numerical investigations of hole injection on the suction side throat of transonic turbine vanes in a cascade with trailing edge injection." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, no. 8 (February 27, 2017): 1454–66. http://dx.doi.org/10.1177/0954410017694918.

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Trailing-edge mixing flows associated with coolant injection are complex, in particular at transonic flows, and result in significant aerodynamics losses. The objective of this paper is to evaluate the impacts of hole injection near the suction side throat on shock wave control and aerodynamic losses. A series of tests and calculations on effects of hole injection on the suction-side throat of a high-pressure turbine vane cascade with and without trailing-edge injection were conducted. Wake traverses with a five-hole probe and tests of pressure distributions on the turbine profile were taken for total injection mass flow ratios of 0% and 1.2% under test Mach numbers of 0.7, 0.78, and 0.87. Meantime, numerical predictions are carried out for exit isentropic Mach numbers of 0.7, 0.78, 0.87, and 1.1 and hole-injection mass flow ratios of 0%, 0.17%, 0.3%, and 0.89%. Numerical predictions show a reasonable agreement with the experimental data, and wake total pressure losses and flow angles as well as pressure distributions on the turbine profile were compared to calculations without hole injection, indicating a significant effect of hole injection on the profile wake development and its blockage effect on the shock-wave flow in the vane cascade passage. At subsonic flows, the hole injection on the suction side throat thickens the suction-side boundary layer, and increases the flow mixing, thus causing increased wake losses and flow angles. At transonic flows, while the trailing-edge injection reduces the strength of the shock wave at the trailing-edge pressure side, the hole injection on the suction side throat alters the local pressure fields, and then tends to enhance the shock-wave at the trailing-edge pressure-side; however, it seems to reduce the strength of the shock-wave at the trailing-edge suction side.

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48

Feuchtwanger, Jorge, Marc L. Richard, Patricia Lázpita, Jon Gutiérrez, José M. Barandiarán, Samuel M. Allen, and Robert C. O'Handley. "Stress-Induced Twin Boundary Motion in Particulate Ni-Mn-Ga /Polymer Composites." Materials Science Forum 583 (May 2008): 197–212. http://dx.doi.org/10.4028/www.scientific.net/msf.583.197.

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Composites of Ni–Mn–Ga particles in a polyurethane matrix can be made by mixing the particles with the polymer, and allowing them to cure under a magnetic field to texture the composites. These composites show large hysteresis and mechanical losses, when subjected to a cyclic stress, that were far larger than the matrix polymer ones. The additional losses are attributed to the motion of twin boundaries in the filler particles and provide a way for obtaining mechanical energy absorption in a wide frequency range. By means of X-ray and neutron diffraction we present evidence that confirms that twins are present in the particles and that they do move when mechanically loading the composite

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49

Kumar, Virendra, Anil Kumar, Surendra Kumar Yadav, Anshul Yadav, Lalta Prasad, and Jerzy Adam Winczek. "Numerical Analysis on a Constant Rate of Kinetic Energy Change Based a Two-Stage Ejector-Diffuser System." Strojniški vestnik - Journal of Mechanical Engineering 68, no. 5 (May 25, 2022): 368–73. http://dx.doi.org/10.5545/sv-jme.2021.7538.

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Supersonic ejector energy flow devices are extensively used in various applications, such as pumping, mixing, compression, etc. The conventional single-stage ejector (SSE) design approaches are inefficient for modelling an efficient ejector because of their inefficiency in minimizing mixing losses in the mixing chamber, thermodynamic shock in constant area diffuser, and utilization of redundant discharged momentum at the exit of the first stage. The physics-based single-stage ejector design has better solutions because it minimizes irreversibility due to thermodynamic shocks. The present study utilizes the constant rate of a kinetic energy change physics-based approach to design a two-stage ejector (TSE) for water vapour. The computational fluid dynamics (CFD) tool ANSYS-Fluent has been utilized to predict flow characteristics. The performance of the ejector-diffuser system has also been compared with a single-stage ejector. It is found that the performance of TSE is 70 % higher than that of the performance of SSE.

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50

Vázquez-Suñé, E., J. Carrera, I. Tubau, X. Sánchez-Vila, and A. Soler. "An approach to identify urban groundwater recharge." Hydrology and Earth System Sciences Discussions 7, no. 2 (April 22, 2010): 2543–76. http://dx.doi.org/10.5194/hessd-7-2543-2010.

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Abstract. Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, ...). The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i) Identification of potential recharge sources, (ii) Selection of tracers, (iii) Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv) Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%), the sewage network losses (30%), rainfall, concentrated in the non-urbanized areas (17%), from runoff infiltration (20%), and the Besòs River (11%). Regarding species, halogens (chloride, fluoride and bromide), sulfate, total nitrogen, and stable isotopes (18O2H, and 34S) behaved quite conservatively. Boron, residual alkalinity, EDTA and Zn did not. Yet, including these species in the computations did not affect significantly the proportion estimations.

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