Journal articles on the topic 'Buoyancy program'
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1
Lesmana, Janice, and Jane Savitri. "Tipe Student Academic Support dan Academic Buoyancy pada Mahasiswa." Humanitas (Jurnal Psikologi) 3, no. 3 (December 22, 2019): 179–200. http://dx.doi.org/10.28932/humanitas.v3i3.2266.
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This study aims to overview the relationship between student academic support (informational, esteem, motivational and venting support) and academic buoyancy in students. 230 participants were selected used proportionate stratified random sampling technique. This study used a modified Student Academic Support Scale (SASS; Thompson & Mazer, 2009) and modified Academic buoyancy Scale (ABS; Martin & Marsh, 2008), correlated using Spearman’s correlation test. The results show that academic buoyancy has a significant positive relationship with esteem support (r = 0.168; p = 0.011), motivational support (r = 0.212; p = 0.001) and venting support (r = 0.158; p = 0.017), but doesn’t have relationship with informational support (r = 0.105; p = 0.111). Researcher suggests to do further research about contribution students' academic support to academic buoyancy. It is recommended to develop a mentoring program for students that facilitates mutual helping, care and motivating between students in the academic.
Keywords: Student Academic Support, Academic buoyancy
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Zhuang, Yizhou, Rong Fu, and Hongqing Wang. "How Do Environmental Conditions Influence Vertical Buoyancy Structure and Shallow-to-Deep Convection Transition across Different Climate Regimes?" Journal of the Atmospheric Sciences 75, no. 6 (May 23, 2018): 1909–32. http://dx.doi.org/10.1175/jas-d-17-0284.1.
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Abstract We developed an entraining parcel approach that partitions parcel buoyancy into contributions from different processes (e.g., adiabatic cooling, condensation, freezing, and entrainment). Applying this method to research-quality radiosonde profiles provided by the Atmospheric Radiation Measurement (ARM) program at six sites, we evaluated how atmospheric thermodynamic conditions and entrainment influence various physical processes that determine the vertical buoyancy structure across different climate regimes as represented by these sites. The differences of morning buoyancy profiles between the deep convection (DC)/transition cases and shallow convection (SC)/nontransition cases were used to assess preconditions important for shallow-to-deep convection transition. Our results show that for continental sites such as the U.S. Southern Great Plains (SGP) and west-central Africa, surface conditions alone are enough to account for the buoyancy difference between DC and SC cases, although entrainment further enhances the buoyancy difference at SGP. For oceanic sites in the tropical west Pacific, humidity dilution in the lower to middle free troposphere (~1–6 km) and temperature mixing in the middle to upper troposphere (>4 km) have the most important influences on the buoyancy difference between DC and SC cases. For the humid central Amazon region, entrainment in both the boundary layer and the lower free troposphere (~0–4 km) have significant contributions to the buoyancy difference; the upper-tropospheric influence seems unimportant. In addition, the integral of the condensation term, which represents the parcel’s ability to transform available water vapor into heat through condensation, provides a better discrimination between DC and SC cases than the integral of buoyancy or the convective available potential energy (CAPE).
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Suhesty, Aulia, and Zafira Noor Basuki. "Penyesuaian Diri dan Efikasi Diri Akademik terhadap Academic Buoyancy." Jurnal Basicedu 6, no. 3 (May 26, 2022): 5456–66. http://dx.doi.org/10.31004/basicedu.v6i3.2763.
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Penelitian ini bertujuan untuk mengetahui mengetahui pengaruh penyesuaian diri dan efikasi diri akademik terhadap academic buoyancy mahasiswa yang bekerja. Metode penelitian yang digunakan adalah kuantitatif. Subjek dalam penelitian ini adalah 107 mahasiswa Sekolah Tinggi X Kota Balikpapan yang bekerja kemudian dipilih dengan menggunakan teknik purposive sampling. Metode pengumpulan data yang digunakan ialah dengan skala academic buoyancy, penyesuaian diri dan efikasi diri akademik. Teknik analisis data yang digunakan ialah regresi linear berganda. Seluruh data yang telah terkumpul dianalisis menggunakan bantuan program Statistical Package for Social Science (SPSS) versi 26.0 for windows. Hasil penelitian menemukan bahwa: (1) terdapat pengaruh yang signifikan penyesuaian diri dan efikasi diri akademik terhadap academic buoyancy pada mahasiswa yang bekerja dengan nilai F hitung = 81.466 > F tabel = 3.08 dan nilai p = 0.000 serta memiliki konstribusi pengaruh (R2) sebesar 61%; (2) terdapat pengaruh yang signifikan penyesuaian diri terhadap academic buoyancy pada mahasiswa yang bekerja dengan nilai koefisien beta (β) = 0.385, t hitung = 4.142 > t tabel = 1.983 , dan nilai p = 0.000 (p < 0.05); (3) terdapat pengaruh yang signifikan efikasi diri akademik terhadap academic buoyancy pada mahasiswa yang bekerja dengan nilai koefisien beta (β) = 0.449, t hitung = 4.823 > t tabel = 1.983, dan nilai p = 0.000 (p < 0.05).
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Thompson, T. E., and J. F. Baker. "Heritability and Phenotypic Correlations of Six Pecan Nut Characteristics." Journal of the American Society for Horticultural Science 118, no. 3 (May 1993): 415–18. http://dx.doi.org/10.21273/jashs.118.3.415.
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Heritability estimates for pecan [Carya illinoinensis (Wangenh.) K. Koch] nut weight, nut buoyancy, nut volume, nut density, kernel weight, and percentage kernel were determined from 8748 nut samples representing 152 families collected during 25 years in the U.S. Dept. of Agriculture (USDA) pecan breeding program at Brownwood, Texas. Measurements were corrected for year-to-year environmental variability using least-squares constants of individual year effects. Adjusted values were then regressed on midparent means. Generally, heritability (h2) estimates were low to moderate: nut weight 0.35, nut buoyancy 0.18, nut volume 0.35, nut density 0.03, kernel weight 0.38, and percentage kernel 0.32. The low values are probably due to the extreme alternate bearing tendency of this species, since crop load affects pecan nut characteristics so directly. Phenotypic correlations among these traits showed that larger or heavier nuts had significantly higher kernel weight, buoyancy, and percentage kernel. Nut density increased with higher nut and kernel weight, but decreased with nut volume.
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Zeng, Xiping, Wei-Kuo Tao, Minghua Zhang, Christa Peters-Lidard, Stephen Lang, Joanne Simpson, Sujay Kumar, et al. "Evaluating Clouds in Long-Term Cloud-Resolving Model Simulations with Observational Data." Journal of the Atmospheric Sciences 64, no. 12 (December 1, 2007): 4153–77. http://dx.doi.org/10.1175/2007jas2170.1.
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Abstract Two 20-day, continental midlatitude cases are simulated with a three-dimensional (3D) cloud-resolving model (CRM) and are compared to Atmospheric Radiation Measurement Program (ARM) data. Surface fluxes from ARM ground stations and a land data assimilation system are used to drive the CRM. This modeling evaluation shows that the model simulates precipitation well but overpredicts clouds, especially in the upper troposphere. The evaluation also shows that the ARM surface fluxes can have noticeable errors in summertime. Theoretical analysis reveals that buoyancy damping is sensitive to spatial smoothers in two-dimensional (2D) CRMs, but not in 3D ones. With this theoretical analysis and the ARM cloud observations as background, 2D and 3D simulations are compared, showing that the 2D CRM has not only rapid fluctuations in surface precipitation but also spurious dehumidification (or a decrease in cloud amount). The present study suggests that the rapid precipitation fluctuation and spurious dehumidification be attributed to the sensitivity of buoyancy damping to dimensionality.
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Ciba, Ewelina, Paweł Dymarski, and Mirosław Grygorowicz. "Analysis of the Hydrodynamic Properties of the 3-Column Spar Platform for Offshore Wind Turbines." Polish Maritime Research 29, no. 2 (June 1, 2022): 35–42. http://dx.doi.org/10.2478/pomr-2022-0015.
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Abstract The article presents a design of a floating platform for offshore wind turbines. The concept is a modification of the Spar design and consists of three variable section columns connected to each other by a ballast tank in the lower part of the platform. This solution makes it possible to influence the position of the centre of buoyancy and the centre of mass of the structure. Compared to the classic Spar platform structure, the centre of buoyancy can be higher than mid-draft, which will provide the platform with greater stability. At the same time, this concept is better, in terms of technology, because of its modular structure and smaller bending radii.On the basis of the model testing performed, the hydrodynamic coefficients of the designed platform and its response to a given regular wave were determined (the transfer functions for heave and pitch motion were determined). Then, based on the damping coefficients, the platform was modelled in the ANSYS AQWA program and the results were very similar.
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Tagkalakis, Athanasios O. "Estimating the Elasticity of Corporate Income Tax to Output Gap in Greece." Public Finance Review 45, no. 2 (August 3, 2016): 205–31. http://dx.doi.org/10.1177/1091142115589971.
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Using quarterly data over the period 1999 to 2013, we estimate the elasticity of corporate income tax (CIT) revenue to output gap in Greece. The elasticity is estimated to be about 1.40 to 1.55 when we use the profit share in its construction, while it increases to 1.83 to 2.05 when profit is used in its construction. The high values of the new estimated elasticity imply substantial CIT buoyancy effects in the years to come, provided that the current reform program of the Greek economy remains on track.
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Ramey, Sandra L., Yelena Perkhounkova, Maria Hein, Nicole L. Bohr, and Amanda A. Anderson. "Testing a Resilience Training Program in Police Recruits: A Pilot Study." Biological Research For Nursing 19, no. 4 (March 30, 2017): 440–49. http://dx.doi.org/10.1177/1099800417699879.
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Background: Stress from multiple sources is inherent in law enforcement. However, it is possible to modify responses to stress with resilience training that includes teaching techniques to modify emotional and physical responses to stress, interface with mental health professionals, and practice sessions to improve self-regulation of responses to stress including coherence, a measure of heart rate variability. A gap exists in the research, however, regarding evaluation of the duration of effects after the initial resilience training. Method: Subjects included ( N = 34) recruits enrolled in summer 2015 at the Milwaukee Police Academy. An experimental design was used to compare recruits who received resilience training to recruits in the control group. Results: No statistically significant differences between the groups were found for self-reported measures of stress and resilience. For the treatment group ( n = 17), change in coherence was significant ( p < .001) and improvement in the Personal Organizational Quality Assessment Emotional Buoyancy subscale correlated significantly with the number of practice sessions ( r = .63, p = .01) and marginally with change in coherence ( r = .47, p = .07). Conclusion: Results confirm several significant effects of resilience training with recruits.
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Jiang, Zhong An, and Wang Yi. "Numerical Simulation of Dynamic Emergency Rescue and Regularities during Mine Fire Period." Advanced Materials Research 619 (December 2012): 336–41. http://dx.doi.org/10.4028/www.scientific.net/amr.619.336.
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Under the comprehensive consideration of “buoyancy effect” and “throttle effect” during mine fire period, the article used the geographic information system (GIS) technology, simulated the smoke pollution area, ventilation system junction temperature and state of airflow during mine fire period. Finishing a program for dynamic simulation of emergency rescue during mine fire period, which is significant for establishing fire pre-scheme and the decision-making during fire period. At the same time, the dynamic characteristic of ventilation system and selection of escaping route is also considered, which provides foundation for the rescuing the workers underground in time.
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Cooper, David, and Ingvil Gausemel. "OIL SPILL SORBENTS: TESTING PROTOCOL AND CERTIFICATION LISTING PROGRAM." International Oil Spill Conference Proceedings 1993, no. 1 (March 1, 1993): 549–51. http://dx.doi.org/10.7901/2169-3358-1993-1-549.
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ABSTRACT Environment Canada's Emergencies Engineering Division is spearheading a program in conjunction with the Canadian General Standards Board that would see the development of a certification and listing program in addition to a national standard for the testing of sorbent materials. Funding for this program is provided by Environment Canada (EC), Canadian Coast Guard (CCG), Marine Spill Response Corporation (MSRC), U.S. Coast Guard (USCG), and U.S. Minerals Management Service (MMS). The test methods are based upon those defined by the American Society for Testing and Materials and previous test methods developed by Environment Canada for our series of reports entitled Selection Criteria and Laboratory Evaluation of Oil Spill Sorbents. This series, which was started in 1975, encompasses a number of commercially available oil spill sorbents tested with different petroleum products and hydrocarbon solvents. The testing program will categorize the sorbents according to their operating characteristics. The main categories are oil spills on water, oil spills on land, and industrial use. The characteristics we will be evaluating with the new test protocols include initial and maximum sorption capacities, water pickup, buoyancy, reuse potential, retention profile, disintegration (material integrity), and ease of application and retrieval. In the near future we plan to incorporate changes to the test that would involve increasing our list of test liquids to encompass spills in an industrial setting, in addition to testing sorbent booms and addressing the disposal problem.
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Simeonov, Julian, and Melvin E. Stern. "Equilibration of Two-Dimensional Double-Diffusive Intrusions." Journal of Physical Oceanography 37, no. 3 (March 1, 2007): 625–43. http://dx.doi.org/10.1175/jpo3000.1.
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Abstract This paper considers the equilibration of lateral intrusions in a doubly diffusive fluid with uniform unbounded basic-state gradients in temperature and salinity. These are density compensated in the horizontal direction and finger favorable in the vertical direction. Previous nonlinear studies of this effect have qualitative and quantitative limitations because of their fictitious parameterizations of the weak “turbulence” that arises. Here, two-dimensional direct numerical simulations (DNS) that resolve scales from the smallest to the intrusive are used to predict the equilibrium state. This is achieved by numerically tilting the x–z computational box so that the mean intrusion is represented by a mode with no lateral variation, but smaller-scale 2D eddies comparable to the intrusion thickness are resolved. The DNS show that the initial plane wave intrusion evolves to an equilibrium state containing both a salt finger interface and a diffusive interface, surrounded by well-mixed layers. The inversion of the horizontally averaged density in the mixed layer is negligibly small, but the salt finger buoyancy flux produces large transient density inversions that drive the mixed layer convection. For the considered values of horizontal/vertical gradients, the calculations yield small Cox numbers and buoyancy Reynolds numbers [comparable to those measured in staircases during the Caribbean-Sheets and Layers Transects (C-SALT) program]. An important testable result is the time-averaged maximum velocity of the fastest-growing intrusion Umax = 18.0 (Σ*z/Σ*x)+1/2KT(gΘ*z/νKT)1/4. Here Θ*z is the undisturbed vertical temperature gradient in buoyancy units, Σ*z and Σ*x are the corresponding vertical and horizontal salinity gradients, g is the gravity acceleration, and ν and KT are the respective values of the molecular viscosity and heat diffusivity. The paradoxical inverse dependence on the horizontal gradient results from the assumption that the latter is unbounded.
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Kim, Kyung Sung, Moo Hyun Kim, and Jong-Chun Park. "Development of Moving Particle Simulation Method for Multiliquid-Layer Sloshing." Mathematical Problems in Engineering 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/350165.
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The mixed oil and gas including water and sand are extracted from well to offshore structure. This mixed fluid must be separated for subsequent processes by using wash tanks or separators. To design such a system, a proper numerical-prediction tool for multiphase fluids is required. In this regard, a new moving particle simulation (MPS) method is developed to simulate multiliquid-layer sloshing problems. The new MPS method for multifluid system includes extra search methods for interface particles, boundary conditions for interfaces, buoyancy-correction model, and surface-tension model for interface particles. The new particle interaction models are verified through comparisons with published numerical and experimental data. In particular, the multiliquid MPS method is verified against Molin et al’s (2012) experiment with three liquid layers. In case of excitation frequency close to one of the internal-layer resonances, the internal interface motions can be much greater than top free-surface motions. The verified multiliquid MPS program is subsequently used for more nonlinear cases including multichromatic multimodal motions with larger amplitudes, from which various nonlinear features, such as internal breaking and more particle detachment, can be observed. For the nonlinear case, the differences between with and without buoyancy-correction and surface-tension models are also demonstrated.
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Chougule, Abhijit, Jakob Mann, Mark Kelly, and Gunner C. Larsen. "Modeling Atmospheric Turbulence via Rapid Distortion Theory: Spectral Tensor of Velocity and Buoyancy." Journal of the Atmospheric Sciences 74, no. 4 (March 14, 2017): 949–74. http://dx.doi.org/10.1175/jas-d-16-0215.1.
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Abstract A spectral tensor model is presented for turbulent fluctuations of wind velocity components and temperature, assuming uniform vertical gradients in mean temperature and mean wind speed. The model is built upon rapid distortion theory (RDT) following studies by Mann and by Hanazaki and Hunt, using the eddy lifetime parameterization of Mann to make the model stationary. The buoyant spectral tensor model is driven via five parameters: the viscous dissipation rate ε, length scale of energy-containing eddies L, a turbulence anisotropy parameter , gradient Richardson number (Ri) representing the local atmospheric stability, and the rate of destruction of temperature variance . Model output includes velocity and temperature spectra and associated cospectra, including those of longitudinal and vertical temperature fluxes. The model also produces two-point statistics, such as coherences and phases of velocity components and temperature. The statistics of uniformly sheared and stratified turbulence from the model are compared with atmospheric observations taken from the Horizontal Array Turbulence Study (HATS) field program, and model results fit observed one-dimensional spectra quite well. For highly unstable stratification, however, the model has deficiencies at low wavenumbers that limit its prediction of longitudinal velocity component spectra at scales on the order of 0.6 km. The model predicts coherences well for horizontal separations but overestimates vertical coherence with increasing separation. Finally, it is shown that the RDT output can deviate from Monin–Obukhov similarity theory.
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Réchou, A., P. Durand, A. Druilhet, and B. Bénech. "Turbulence structure of the boundary layer below marine clouds in the SOFIA experiment." Annales Geophysicae 13, no. 10 (October 31, 1995): 1075–86. http://dx.doi.org/10.1007/s00585-995-1075-y.
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Abstract. The SOFIA (Surface of the Ocean: Flux and Interaction with the Atmosphere) experiment, included in the ASTEX (Atlantic Stratocumulus Transition Experiment) field program, was conducted in June 1992 in the Azores region in order to investigate air-sea exchanges, as well as the structure of the atmospheric boundary layer and its capping low-level cloud cover. We present an analysis of the vertical structure of the marine atmospheric boundary layer (MABL), and especially of its turbulence characteristics, deduced from the aircraft missions performed during SOFIA. The meteorological situations were characteristic of a temperate latitude under anticyclonic conditions, i.e., with weak to moderate winds, weak surface sensible heat flux, and broken capping low-altitude cloud cover topped by a strong trade inversion. We show that the mixed layer, driven by the surface fluxes, is decoupled from the above cloud layer. Although weak, the surface buoyancy flux, and the convective velocity scale deduced from it, are relevant for scaling the turbulence moments. The mixed layer then follows the behaviour of a continental convective boundary layer, with the exception of the entrainment process, which is weak in the SOFIA data. These results are confirmed by conditional sampling analysis, which shows that the major turbulence source lies in the buoyant moist updrafts at the surface.
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Yeager, Stephen. "Topographic Coupling of the Atlantic Overturning and Gyre Circulations." Journal of Physical Oceanography 45, no. 5 (May 2015): 1258–84. http://dx.doi.org/10.1175/jpo-d-14-0100.1.
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AbstractThe vorticity dynamics associated with the mean and time-varying gyre and overturning circulations of the Atlantic Ocean are examined in a realistic ocean model hindcast simulation of the late twentieth century. Abyssal flow interaction with sloping bottom bathymetry gives rise to the bottom pressure torque (BPT) term of the vertically integrated vorticity equation. The dominance of this term in the closure of the barotropic gyre circulation noted in previous studies is corroborated here for both non-eddy-resolving and eddy-resolving versions of the Parallel Ocean Program (POP) model. This study shows that BPT is also a dominant term in the vorticity balance of the Atlantic meridional overturning circulation (AMOC) and therefore represents a key dynamical link between the overturning and gyre streamfunctions. The interannual variability of the Atlantic circulation over the last several decades, viewed in terms of time-varying integral vorticity balances, demonstrates the fundamental role played by BPT in coupling the large-scale barotropic and baroclinic flows. Forcing perturbation experiments show how flow–bathymetry interactions mediate buoyancy-driven changes in the gyre circulation and momentum-driven changes in the AMOC. Examples of topographic coupling of the overturning and gyre circulations that this analysis elucidates include the covariation of the high-latitude AMOC and subpolar gyre flows on decadal time scales, buoyancy-forced variance of the Gulf Stream, and large wind-driven variations in AMOC at subtropical latitudes.
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Garbino, Alejandro, Robert W. Sanders, and Charles H. Mathers. "Hypertension screening of commercial divers from an occupational medicine perspective." Undersea and Hyperbaric Medicine 44, no. 2 (March 1, 2017): 133–39. http://dx.doi.org/10.22462/3.4.2017.6.
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Hypertension is one of the most common chronic diseases in the world: in the United States, it affects one-third of the adult population. Most cases are primary hypertension – with no identified cause – and significantly increase risk for cardiovascular disease and stroke. At NASA’s Neutral Buoyancy Laboratory (NBL), there is a cadre of professional divers who provide underwater support during extravehicular activity training (EVAs, commonly referred to as “spacewalks”) for astronauts. The NBL occupational health program requires regular “work-site” physical exams, including blood pressure checks, on at least a weekly basis. Although some blood pressures measured during such regular checks were elevated, the diagnosis and management of blood pressure was outside the scope of that occupational medicine program. As a result, there was no protocol to analyze and manage asymptomatic elevated blood pressure if and when it warranted physician follow-up. We therefore analyzed the blood pressure data from all divers in 2015, vetted the worksite physical and developed a referral pathway to ensure divers have access to effective management of their blood pressure while minimizing impact of such a program on daily operations.
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Wilerson Calil, Vinicius Rubio, and Jorge Inhasz. "DEVELOPMENT OF A PROGRAM FOR THE DETERMINATION OF THE TEMPERATURE AT TRANSFORMERS COPPER BUS BARS BY CALCULATING THEIR DIMENSIONLESS NUMBERS." Journal of Energy - Energija 61, no. 1-4 (July 19, 2022): 139–48. http://dx.doi.org/10.37798/2012611-4246.
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The present technical study aims to demonstrate how to make the determination of the temperature at Transformers Copper Bus Bars by calculating their dimensionless numbers its will explain about the development of a thermal software that represents a viable and cost-effective to dimensioning the transformers Bus Bars due the temperature rise generate by the current. In this environment, the program is basically a virtual lab where is only necessary the cost of specialized engineering analysis and the critical time analysis. This program allows to be done a large number of tests with different types of Bus Bars and different positions of this Bus Bars with the main objective of loss and temperature reduction, material and final cost of the equipment it can also be used to avoid a possible re-work, non-acceptance or disapproval in heating tests, improving the overall performance of the equipment. To find the temperature at the Bus Bar was necessary to calculate the losses at the Bus Bars and the dimensionless numbers of Prandtl which is the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity, Grashof which is a dimensionless number in fluid dynamics and heat transfer which approximates the ratio of the buoyancy to viscous force acting on a fluid, Rayleigh which is associated with buoyancy driven flow (also known as free convection or natural convection) and is the product of the Grashof number and the Prandtl number also and finally Nusselt which is the ratio of convective to conductive heat transfer across (normal to) the boundary. The conductive component is measured under the same conditions as the heat convection but with a (hypothetically) stagnant (or motionless) fluid. All dimensionless numbers were considered for natural convection. To do this calculation an analytical program using Visual Basic at MSExcel was created. To find this temperature some variables are dependent. In that case, this variables need to be fixed after the first temperature found at copper Bus Bars. Some iterations must be done using the program starting from this first temperature to find the correct final temperature. After this procedure is possible to determinate the temperature considering the paper layer of the copper Bus Bars when it exists. The measured results show the reliability of the proposed model by calculating the dimensionless numbers for the determination of the temperature at Transformers copper Bus Bars.
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Ji, Ming Ming, Lin Hua Piao, and Bai Hua Li. "Three-Dimensional FEM Analysis of the Gas Pendulum Characteristic for Airflow Level Posture Sensor." Advanced Materials Research 271-273 (July 2011): 216–19. http://dx.doi.org/10.4028/www.scientific.net/amr.271-273.216.
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Using ANSYS-FLOTRAN CFD program, the finite element simulation is conducted by a series of procedures, such as three-dimensional model building of airflow inclination sensor, network modifying, loads applying and equation solving. The flow field in three-dimensional hermetic chamber of sensitive element of airflow level posture sensor is calculated, FEM analysis has been obtained. The numerical results show that under the buoyancy lift affecting, the direction of nature convection gas always keeps the vertical upward in two-dimensional enclosure, nature convection gas has the pendulum characteristic, and when the dimensional enclosure is inclined, temperature distribution at the several points in dimensional enclosure will change with the tilt angle. The pendulum characteristic can be utilized to measure the level posture by the airflow level posture sensor.
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Wahab, Faisal. "Desain Awal Pembuatan Glider Autonomous Underwater Vehicle (AUV) Parahyangan." JTERA (Jurnal Teknologi Rekayasa) 4, no. 1 (May 14, 2019): 29. http://dx.doi.org/10.31544/jtera.v4.i1.2019.29-36.
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Perkembangan teknologi robot bawah air saat ini menjadi banyak perhatian. Salah satu jenis robot bawah air adalah Glider Autonomous Underwater Vehicle (AUV). Robot ini dapat bekerja secara otomatis tanpa operator berdasarkan perubahan daya apung (buoyancy) agar dapat bekerja dalam tiga kondisi, yaitu mengapung, melayang, dan tenggelam. Penelitian ini merupakan desain awal dan pembuatan Glider AUV Parahyangan berbiaya rendah. Robot yang dirancang terdiri dari sistem elektrik, mekanik, dan program. Robot ini dibuat memiliki satu derajat kebebasan yaitu menggerakan sudut pitch dengan menggunakan dua buah penggerak. Penggerak pertama digunakan untuk mengubah daya apung dengan memasukan air ke dalam tangki robot, sedangkan penggerak kedua digunakan untuk menggeser movable mass sehingga sudut pitch robot ini dapat dikendalikan. Hasil eksperimen menunjukan sistem elektrik, mekanik, dan program dapat bekerja sesuai dengan perancangan. Robot ini diujicobakan juga dengan diberi setpoint sudut pitch sebesar 14° dan hasilnya robot dapat mencapai set point pada detik ke-46. Pada uji coba tersebut, robot mengalami osilasi ketika menuju setpoint yang yang disebabkan oleh getaran motor stepper. Namun demikian, osilasi dapat berkurang saat robot mencapai setpoint.
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Koteja, Agnieszka, Katarzyna Kucia, Małgorzata Potocka-Mitan, Grażyna Kosiba, Maria Gacek, Joanna Gradek, and Magda Majer. "The impact of Aqua Pilayoga program on functional fitness in elderly women." Journal of Kinesiology and Exercise Sciences 31, no. 96 (December 30, 2021): 55–60. http://dx.doi.org/10.5604/01.3001.0015.7583.
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Background: The literature highlights the benefits of physical activity using water resistance during movement in the aquatic environment, and the combination of pilayoga with the activity in the aquatic environment offers an interesting alternative to modern training and inspires research in this field. Nowadays, aquatic fitness is one of the most widely recognized fitness programs among health specialists, sports professionals, and practitioners. Aims: The main aim of the study was to assess the effect of three months of participation in an aqua pilayoga program on the functional fitness of women over 60 years of age. Method: The study group followed a supervised training routine 2 times per week for 3 months. The variables assessed at baseline and after 3 months included body composition (BIA), anthropometric indices i.e. body mass index, and results of the Fullerton Fitness Senior Test (FFST) which evaluated functional fitness. Fitness parameters measured in the study were strength and muscular endurance, mobility, dexterity, speed, body balance, motor coordination, reaction time, and flexibility. Results: After 3 months of the experiment, the greatest changes were found in endurance, agility, and strength of the upper and lower limbs. Positive adaptations were also observed in increased leg strength and flexibility of the lower and upper body. After 3 months, body mass index and fat mass decreased significantly (p<0.05), whereas basal metabolic rate, fat-free mass, and total body water increased significantly (p<0.001) Conclusions: Our findings indicated that aqua pilayoga programs can improve health parameters better and faster than in other sports. This is probably related to the specificity of the aquatic environment (buoyancy, density, resistance force, or waves) and physical exercise in water.
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Viglione, Giuliana A., Andrew F. Thompson, M. Mar Flexas, Janet Sprintall, and Sebastiaan Swart. "Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results." Journal of Physical Oceanography 48, no. 9 (September 2018): 2011–27. http://dx.doi.org/10.1175/jpo-d-17-0192.1.
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AbstractEnhanced vertical velocities associated with submesoscale motions may rapidly modify mixed layer depths and increase exchange between the mixed layer and the ocean interior. These dynamics are of particular importance in the Southern Ocean, where the ventilation of many density classes occurs. Here we present results from an observational field program in southern Drake Passage, a region preconditioned for submesoscale instability owing to its strong mesoscale eddy field, persistent fronts, strong down-front winds, and weak vertical stratification. Two gliders sampled from December 2014 through March 2015 upstream and downstream of the Shackleton Fracture Zone (SFZ). The acquired time series of mixed layer depths and buoyancy gradients enabled calculations of potential vorticity and classifications of submesoscale instabilities. The regions flanking the SFZ displayed remarkably different characteristics despite similar surface forcing. Mixed layer depths were nearly twice as deep, and horizontal buoyancy gradients were larger downstream of the SFZ. Upstream of the SFZ, submesoscale variability was confined to the edges of topographically steered fronts, whereas downstream these motions were more broadly distributed. Comparisons to a one-dimensional (1D) mixing model demonstrate the role of submesoscale instabilities in generating mixed layer variance. Numerical output from a submesoscale-resolving simulation indicates that submesoscale instabilities are crucial for correctly reproducing upper-ocean stratification. These results show that bathymetry can play a key role in generating dynamically distinct submesoscale characteristics over short spatial scales and that submesoscale motions can be locally active during summer months.
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Mei, Chuan Zhi, Lin Hua Piao, Quan Gang Yu, Bao Li Zhang, Xia Ding, and Xing Wang. "Study on the Pendulum Characteristic of Nature Convection in Dimensional Enclosure." Advanced Materials Research 542-543 (June 2012): 1120–23. http://dx.doi.org/10.4028/www.scientific.net/amr.542-543.1120.
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In this paper, the pendulum characteristic of nature convection gas in dimensional enclosure is analyzed by FEM. Using ANSYS-FLOTRAN CFD program, the stream field and the temperature field caused by the point heat source, when the two-dimensional enclosure is inclined, has been obtained by a series of procedure, such as model building, meshing, loads applying and equation solving. The results are as follow: (1)Under the buoyancy lift affecting, the direction of nature convection gas always keeps the vertical upward in two-dimensional enclosure, nature convection gas has the pendulum characteristic. (2)When the dimensional enclosure is inclined, temperature distribution at the several points in dimensional enclosure will change with the tilt angle. The pendulum characteristic can be utilized to measure the tilt angle by the gas pendulum tilt sensor.
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Yu, Quan Gang, Lin Hua Piao, and Xing Wang. "FEM Analysis of the Pendulum Characteristic of Nature Convection in Dimensional Enclosure." Advanced Materials Research 505 (April 2012): 195–98. http://dx.doi.org/10.4028/www.scientific.net/amr.505.195.
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In this paper, the pendulum characteristic of nature convection gas in dimensional enclosure is analyzed by FEM. Using ANSYS-FLOTRAN CFD program, the stream field and the temperature field caused by the point heat source, when the two-dimensional enclosure is inclined, has been obtained by a series of procedure, such as model building, meshing, loads applying and equation solving. The results are as follow: (1)Under the buoyancy lift affecting, the direction of nature convection gas always keeps the vertical upward in two-dimensional enclosure, nature convection gas has the pendulum characteristic. (2)When the dimensional enclosure is inclined, temperature distribution at the several points in dimensional enclosure will change with the tilt angle. The pendulum characteristic can be utilized to measure the tilt angle by the gas pendulum tilt sensor.
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Ingel, L. Kh. "TO THE NONLINEAR DYNAMICS OF TURBULENT THERMALS." XXII workshop of the Council of nonlinear dynamics of the Russian Academy of Sciences 47, no. 1 (April 30, 2019): 61–63. http://dx.doi.org/10.29006/1564-2291.jor-2019.47(1).16.
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Often used model of turbulent convection from localized sources of buoyancy and (or) momentum acting for a short time – isolated thermals. In such a model, the perturbation region (thermal) is approximately represented as a “bubble” or a vortex ring of variable volume and mass that rises (or descends depending on the perturbation sign). The volume of thermals is gradually increasing due to the capture of adjacent volumes of the environment (“entrainment”). The dynamics of a thermal is described by a nonlinear system of ordinary differential equations – the equations of balance of mass, momentum and buoyancy. In the present work, the nonlinear integral model of turbulent thermals is generalized to the case of the presence of horizontal components of its motion relative to the medium (for example, the emergence of a thermal in a shear flow). Compared to traditional models, the possibility of the presence in the thermal of volume heat and momentum sources is additionally taken into account. The problem is solved in quadratures. One of the possible applications is the artificial stimulation by local sources of impulse of downward movements in the atmosphere in order to influence convective clouds. The solution depends on nine parameters – stratification, vertical shear of the background current, intensities of the above-mentioned volume sources, initial conditions for the thermal radius, its buoyancy, and the three components of the thermal velocity. Different limiting cases are analyzed. Attention is paid to the nonlinear effect of the interaction of the horizontal and vertical components of the thermal motion, since each of the components affects the intensity of entrainment, i.e. on the growth rate of thermal dimensions and, consequently, on its mobility. Intensification of entrainment due to the interaction of a thermal with a transverse flow can lead to a significant decrease in its mobility. From this, in turn, depends on the degree of horizontal transfer of a thermal by a background current. Some limiting cases were previously analyzed in the author’s cited below. This study was supported by Program 56 of the Fundamental Research of the Presidium of the Russian Academy of Sciences.
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Parvin, Shahanaz, Siti Suzilliana Putri Mohamed Isa, Norihan Md Arifin, and Fadzilah Md Ali. "The Inclined Factors of Magnetic Field and Shrinking Sheet in Casson Fluid Flow, Heat and Mass Transfer." Symmetry 13, no. 3 (February 25, 2021): 373. http://dx.doi.org/10.3390/sym13030373.
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The development of the mathematical modeling of Casson fluid flow and heat and mass transfer is presented in this paper. The model is subjected to the following physical parameters: shrinking parameter, mixed convection, concentration buoyancy ratio parameter, Soret number, and Dufour number. This model is also subjected to the inclined magnetic field and shrinking sheet at a certain angle projected from the y- and x-axes, respectively. The MATLAB bvp4c program is the main mathematical program that was used to obtain the final numerical solutions for the reduced ordinary differential equations (ODEs). These ODEs originate from the governing partial differential equations (PDEs), where the transformation can be achieved by applying similarity transformations. The MATLAB bvp4c program was also implemented to develop stability analysis, where this calculation was executed to recognize the most stable numerical solution. Numerical graphics were made for the skin friction coefficient, local Nusselt number, local Sherwood number, velocity profile, temperature profile, and concentration profile for certain values of the physical parameters. It is found that all the governed parameters affected the variations of the Casson fluid flow, heat transfer, mass transfer, and the profiles of velocity, temperature, and concentration. In addition, a stable solution can be applied to predict the impact of physical parameters on the actual fluid model by using a mathematical fluid model.
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Yongchao, Liu, Liu Xiuwen, Luan Xin, and Xie Xingtao. "Bending moment analysis of super large ore carrier based on graphical interface development." E3S Web of Conferences 283 (2021): 01035. http://dx.doi.org/10.1051/e3sconf/202128301035.
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In order to improve the safety of shipping process, this paper designs a graphical user interface for calculating the static water bending moment of super large ore earner. Due to the complexity of the actual loading conditions, the long hull girder and the mobility and sinking of cargo, the irregular distribution of gravity and buoyancy along the direction of the captain of the VLCC is prominent. In the actual loading process of ships, compartment loading is adopted in many cases, and the position where the maximum shear force and bending moment appear is generally not in the corresponding position. Traditional ship strength analysis methods can be divided into two kinds. One is to establish the ship’s finite element model to calculate the ship’s strength. The other is to calculate the ship’s strength according to the simple beam bending theory. In this paper, a 360m VALE MAX ore carrier is taken as an example to calculate the local bending moment of the ship at a specific position by using QT software. Compared with the ship loading manual, the error of the program is small, and the program has guiding significance in the actual shipping process.
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Spanos, Pol D., Rupak Ghosh, Lyle D. Finn, and John Halkyard. "Coupled Analysis of a Spar Structure: Monte Carlo and Statistical Linearization Solutions." Journal of Offshore Mechanics and Arctic Engineering 127, no. 1 (February 1, 2005): 11–16. http://dx.doi.org/10.1115/1.1862253.
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The response of a combined dynamic system consisting of a Spar, a mooring line system, and top tension risers is presented. The top tension of a riser is provided by a buoyancy-can that is laterally supported by a preloaded compliant guide. The overall system is nonlinear due to the mooring line restoring force, the friction between the buoyancy-cans and the compliant guides, and the friction between the risers and the guides at the Spar keel. The friction between the Spar and the riser system is captured by a Coulomb model, whereas the stiffness of the mooring line system is accounted for by using a nonlinear regression analysis of pertinent load versus displacement data. The combined model is numerically integrated using input time histories of force and moment that are compatible with a random representation (Jonswap spectrum) of a typical extreme environmental loading in the Gulf of Mexico. The input time histories of the force and the moment for the combined model are obtained at the center of gravity of the Spar by using a standard motion analysis program (MLTSIM). The numerical results of the time domain analysis of the combined model, in conjunction with ergodicity, are used for an associated Monte Carlo study. The Monte Carlo study provides useful information regarding the probability densities and the power spectra of various response components of the combined system. These results serve as a benchmark for additional analytical studies that call attention to the potential usefulness of the technique of statistical linearization for efficient dynamic analyses of preliminary design decisions regarding the combined Spar–Risers–Mooring lines system.
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Cochrane, J., and P. Carpenter. "Characterization of Semiconductors Grown in a Rotating Magnetic Field." Microscopy and Microanalysis 7, S2 (August 2001): 568–69. http://dx.doi.org/10.1017/s1431927600028919.
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Many different techniques have been used in attempts to minimize defects in single crystal semiconductors. This study examines semiconductors grown in the presence of a rotating magnetic field (RMF). The RMF method is commonly used in metallurgy to stir an electrically conducting liquid during the casting process which can reduce the effects of buoyancy driven convection and enhance the mass transfer process. The variation of heat and mass transfer processes by RMF can be controlled by selecting a specific frequency and strength of the magnetic field. Both numerical modeling and space-based crystal growth experiments using RMF indicate that the application of RMF to solidification of semiconductors will dramatically minimize defects and inclusions.A ground based program in the Microgravity Research Division at NASA's Marshall Space Flight Center has been studying the effects of RMF on various semiconductor compounds grown by the traveling heater method (THM).
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Bertrand, Gary L. "Buoyancy programs." Journal of Chemical Education 67, no. 11 (November 1990): 922. http://dx.doi.org/10.1021/ed067p922.3.
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Parvin, Shahanaz, Siti Suzilliana Putri Mohamed Isa, Fuad S. Al- Duais, Syed M. Hussain, Wasim Jamshed, Rabia Safdar, and Mohamed R. Eid. "The flow, thermal and mass properties of Soret-Dufour model of magnetized Maxwell nanofluid flow over a shrinkage inclined surface." PLOS ONE 17, no. 4 (April 29, 2022): e0267148. http://dx.doi.org/10.1371/journal.pone.0267148.
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A mathematical model of 2D-double diffusive layer flow model of boundary in MHD Maxwell fluid created by a sloping slope surface is constructed in this paper. The numerical findings of non-Newtonian fluid are important to the chemical processing industry, mining industry, plastics processing industry, as well as lubrication and biomedical flows. The diversity of regulatory parameters like buoyancy rate, magnetic field, mixed convection, absorption, Brownian motion, thermophoretic diffusion, Deborah number, Lewis number, Prandtl number, Soret number, as well as Dufour number contributes significant impact on the current model. The steps of research methodology are as followed: a) conversion from a separate matrix (PDE) to standard divisive calculations (ODEs), b) Final ODEs are solved in bvp4c program, which developed in MATLAB software, c) The stability analysis part also being developed in bvp4c program, to select the most effective solution in the real liquid state. Lastly, the numerical findings are built on a system of tables and diagrams. As a result, the profiles of velocity, temperature, and concentration are depicted due to the regulatory parameters, as mentioned above. In addition, the characteristics of the local Nusselt, coefficient of skin-friction as well as Sherwood numbers on the Maxwell fluid are described in detail.
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جلال, اسلام احمد, محمد مصدق, احمد عادل فوزى جمال جمال, and خالد محمد عبد الکریم محمد عبد الکریم. "تأثیر برنامج تدریبى مقترح للطفو على بعض المهارات فى ریاضة الغوص-Effect of Natural buoyancy training program on some of Scuba diving skills." المجلة العلمیة للتربیة البدنیة وعلوم الریاضة. جامعة حلوان 92, no. 5 (August 1, 2021): 1–19. http://dx.doi.org/10.21608/jsbsh.2021.81935.1742.
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Cwudzinski, A. "Numerical Prediction of Hydrodynamic Conditions in one Strand Tundish. Influence of Thermal Conditions and Casting Speed/ Numeryczna Prognoza Warunków Hydrodynamicznych W Jednozyłowej Kadzi Posredniej. Wpływ Warunków Cieplnych I Predkosci Odlewania." Archives of Metallurgy and Materials 59, no. 4 (December 1, 2014): 1249–56. http://dx.doi.org/10.2478/amm-2014-0214.
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Abstract This paper reports the results of computer simulations of the flow of liquid steel in a single-nozzle tundish, which describe the flow hydrodynamics, depending on the thermal conditions and casting speed. In this paper, five casting speeds, namely 0.3, 0.6, 0.9, 1.2 and 1.5 m/min., have been examined. In view of the fact that tundishes are being equipped with various flow control devices and the process of creating specific hydrodynamic conditions is influenced also by the temperature gradient, computer simulations of liquid steel flow under isothermal and non-isothermal conditions were performed. Computer simulations of liquid steel flow were performed using the commercial program Ansys-Fluent ®. In order to explain the phenomena occurring in the tundish working space, the buoyancy number (Bu) has been calculated. The next research step in the analysis of the flow pattern forming in different casting conditions was to record the E and F-type RTD characteristics and to describe the pattern of flow.
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Tamsalu, Rein, Kai Myberg, and Juha Sarkkula. "Hydrodynamic and Ecological Models for the Gulf of Finland." Water Quality Research Journal 29, no. 2-3 (May 1, 1994): 343–64. http://dx.doi.org/10.2166/wqrj.1994.021.
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Abstract Measurement programs and model simulations of hydrodynamics and ecology of the Gulf of Finland, a sub-basin of the Baltic Sea, have been carried out from the 1970s. The measurements indicate that there exists a wind-independent background current in the gulf. A 2.5-D baroclinic, prognostic, hydrodynamic model has been developed. The vertical structure of temperature and salinity is based on a self-similarity structure of the sea. The model results showed that the background current in the measurements can be explained by the important role of buoyancy-driven circulation in the studied area. There are quasi-stationary fronts of salinity and velocity in the gulf. The maintenance of these fronts is based on the opposing effects of river water discharge and salty water input from the main Baltic Sea. These processes are modified by the baroclinic circulation and bottom topography. A box model for calculation of ecosystem characteristics was developed for the Gulf of Finland. The plankton organisms are divided into size classes. The aquatic ecosystem characteristics were calculated by using the results of the hydrodynamic model (flow velocity, temperature, salinity, density, sea level and turbulent fluxes) as input data. The verification of the model was carried out against the Baltic Monitoring Program (BMP) data. Long-term water quality simulations were done by changing external nutrient load.
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Puolakanaho, Anne, Raimo Lappalainen, Päivi Lappalainen, Joona S. Muotka, Riikka Hirvonen, Kenneth M. Eklund, Timo P. S. Ahonen, and Noona Kiuru. "Reducing Stress and Enhancing Academic Buoyancy among Adolescents Using a Brief Web-based Program Based on Acceptance and Commitment Therapy: A Randomized Controlled Trial." Journal of Youth and Adolescence 48, no. 2 (December 17, 2018): 287–305. http://dx.doi.org/10.1007/s10964-018-0973-8.
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Elbenghazi, E., K. Agha, and E. Dekam. "Simulation Of Indirect Solar Crop Dryers Augmented With Pebble-Bed Thrmal Storages." Solar Energy and Sustainable Development Journal 6, no. 1 (June 30, 2017): 1–12. http://dx.doi.org/10.51646/jsesd.v6i1.50.
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This paper presents a model of indirect solar dryer augmented with pebble bed thermal storage. The thermal storage system was considered to be placed inside the drying chamber above the 47°-tilted air solar collector and below the crop bed, where an average September-daily insolation profile was given for the 32°N location. A presented mathematical model took into consideration the pressure and natural buoyancy forces, employed the basic governing equations, atmospheric-air psychometric-chart relations, and published correlation relationships. A “QBASIC” computer program was written based on the trial and error method for the calculation of different parameters. Dimensions of the dryer system, position, and characteristics of the crop and storage beds, strongly affected the behavior of the dryer system, for both rice and tomato products. Referring to the considered indirect solar dryer design type, on average two and five days were required for rice and tomatoes long-term drying, respectively. This seems to be visible in rice products, however, it is far from applicability for tomatoes mass-drying process in agricultural fields, due to its high initial moisture content.
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Rocha, Helena A., Daniel A. Marinho, Nuno D. Garrido, Liliane S. Morgado, and Aldo M. Costa. "The acquisition of aquatic skills in preschool children: deep versus shallow water swimming lessons." Motricidade 14, no. 1 (May 24, 2018): 66. http://dx.doi.org/10.6063/motricidade.13724.
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One of the key factors in the swimming teaching-learning process seems to be the variation of water’s depth.However, there are almost no studies about this topic and the existing ones usually follow a basic approach and with no control of the educational program used. It was our purpose to determine the effect of deep versus shallow water differences on developing pre-schoolers’ aquatic skills after 6 months of practice. Twenty-one Portuguese school-aged children of both genders (4.70 ± 0.51 yrs.), inexperienced in aquatic programs, participated in this study. The children were divided into two groups performing a similar aquatic program but in a different water depth: shallow water (n=10) and deep water (n=11). Each participant was evaluated twice for their aquatic readiness using an observation check list of 17 aquatic motor skills: during the first session (T0) and after six months of practice (two sessions per week with a total of 48 sessions) (T1). The aquatic proficiency on each skill was compared between the groups and a stepwise discriminant analysis was conducted to predict the conditions with higher or lower aquatic competence. Results suggested that swimming practice contributed positively to improvements on several basic aquatic skills, in both groups. The results showed that shallow water group managed to acquire a higher degree of aquatic competence particularly in five basic aquatic skills (p< .05): breath control combined with face immersion and eye opening; horizontal buoyancy; body position at ventral gliding; body position at dorsal gliding; leg kick with breath control at ventral body position, without any flutter device. The discriminant function revealed a significant association between both groups and four included factors (aquatic skills) (p< .001), accounting for 88% between group variability. The body position at ventral gliding was the main relevant predictor (r=0.535). Shallow water swimming lessons generated greater aquatic competence in preschool children after a period of 6 months of practice.
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Acharya, Govatsa, Fredrik Dehlin, Sara Bortot, and Ignas Mickus. "INVESTIGATION OF A SELF-ACTUATED, GRAVITY-DRIVEN SHUTDOWN SYSTEM IN A SMALL LEAD-COOLED REACTOR." EPJ Web of Conferences 247 (2021): 07007. http://dx.doi.org/10.1051/epjconf/202124707007.
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Passive safety systems in a nuclear reactor allow to simplify the overall plant design, beside improving economics and reliability, which are considered to be among the salient goals of advanced Generation IV reactors. This work focuses on investigating the application of a self-actuated, gravity-driven shutdown system in a small lead-cooled fast reactor and its dynamic response to an initiating event. The reactor thermal-hydraulics and neutronics assessment were performed in advance. According to a first-order approximation approach, the passive insertion of shutdown assembly was assumed to be influenced primarily by three forces: gravitational, buoyancy and fluid drag. A system of kinematic equations were formulated a priori and a MATLAB program was developed to determine the dynamics of the assembly. Identifying the delicate nature of the balance of forces, sensitivity analysis for coolant channel velocities and assembly foot densities yielded an optimal system model that resulted in successful passive shutdown. Transient safety studies, using the multi-point dynamics code BELLA, showed that the gravity-driven system acts remarkably well, even when accounting for a brief delay in self-actuation. Ultimately the reactor is brought to a sub-critical state while respecting technological constraints.
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Valanto, Petri. "Active Flooding Mitigation for Stability Enhancement in a Damaged RoPax Ship." Journal of Marine Science and Engineering 10, no. 6 (June 9, 2022): 797. http://dx.doi.org/10.3390/jmse10060797.
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In the framework of the EU project Flooding Accident Response (FLARE), flooding mitigation on a RoPax ship was studied using different active methods to improve ship safety in damage cases leading to a hull breach and flooding. Adding active flooding control systems to ship designs and ships in service, which would mitigate the effects of flooding in a damage case, could be an attractive way to improve ship safety. In order to promote this idea, the effects of such active measures on the ship safety were studied: the choice of them, the required application speed of them, their functionality in waves, the numerical modeling of them, and finally testing them with model scale tests. The following flooding mitigation methods were studied: (1) counter flooding, (2) the recovery of lost buoyancy in a damaged compartment, and (3) deploying a watertight barrier on the trailer deck. This study consists of the numerical simulations carried out with the program HSVA Rolls in chosen damage cases on a current RoPax design, with and without active flooding mitigation measures, and of the following ship model tests based on the a priori computations.
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Viecili, Giannin, Abd El Halim Omar Abd El Halim, Abass Braimah, and Osama El-Desouky. "Transportation Optimization of Ribbon Floating Bridges: Analytical and Experimental Investigation." Open Civil Engineering Journal 8, no. 1 (March 7, 2014): 42–56. http://dx.doi.org/10.2174/1874149501408010042.
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Floating bridges are an economical and practical alternative for crossing water obstacles, especially in times of emergencies and conflicts. Ribbon pontoon floating bridges are a special type of floating bridge designed, built, stockpiled and deployed by the military and emergency management organizations in times of need. They are light-weight, fast to erect, and use the buoyancy of water to aid in supporting their self-weight and traffic loads imposed on the bridge. With increasing vehicular weights and fast bridge traversing time requirements, it has become necessary to develop reliable analytical tools capable of designing and analyzing floating bridges. It is critical to ensure that ribbon pontoon floating bridges can accommodate heavier vehicles, and at the same time reduce the spacing between successive vehicles to achieve greater transportation and economic efficiency. This paper presents the outline and results of an analytical and experimental research program designed to study the dynamic behavior of ribbon pontoon floating bridges under two-axle vehicular loading. An innovative experimental model was designed, constructed, and used in the experimental study. The developed analytical model predicted, with reasonable accuracy, maximum bridge displacements at different vehicle speeds and weights when compared with the experimental results.
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Rasheed, Suhad A., and Abeer Aamer Mahmood. "Free Convection Heat Transfer Around a Cylinder Embedded in an Enclosure Filled with Porous Media." Al-Nahrain Journal for Engineering Sciences 23, no. 1 (March 20, 2020): 51–60. http://dx.doi.org/10.29194/njes.23010051.
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An experimental and theoretical study of free convection heat transfer for a cylinder placed in an iron test section of dimensions (0.2x0.2x0.2 m3), the test section filled with saturated porous material glass balls (5 mm), and the air is the working fluid with Raleigh number (7692.6 ≤ Ra ≤ 17654). The circular cylinder heater (D = 0.015 m, L = 0.2 m) is heated electrically, made of Copper and located in different positions (in X & Y direction). The theoretical part includes solving the free convection heat transfer using the ANSYS program (fluent). The experimental and theoretical results showed that the surface temperature values around the cylinder perimeter when changing its position within the test section are changing as moving up and down where the effect of buoyancy force appears. The maximum difference between the upper and lower position at the experimental result is 7.22%, and the average Nusselt number increases with Raleigh number and heat flux. Also, the experimental results showed that the use of porous material significantly improves the heat transfer by 48.6%. The maximum percentage change between the experimental and theoretical results is 5.46%. Moreover, experimental correlations were achieved, and a comparison was performed between the present results with the previous studies and it gives a good agreement.
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Polzin, Kurt L., Binbin Wang, Zhankun Wang, Fred Thwaites, and Albert J. Williams. "Moored Flux and Dissipation Estimates from the Northern Deepwater Gulf of Mexico." Fluids 6, no. 7 (June 30, 2021): 237. http://dx.doi.org/10.3390/fluids6070237.
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Results from a pilot program to assess boundary mixing processes along the northern continental slope of the Gulf of Mexico are presented. We report a novel attempt to utilize a turbulence flux sensor on a conventional mooring. These data document many of the features expected of a stratified Ekman layer: a buoyancy anomaly over a height less than that of the unstratified Ekman layer and an enhanced turning of the velocity vector with depth. Turbulent stress estimates have an appropriate magnitude and are aligned with the near-bottom velocity vector. However, the Ekman layer is time dependent on inertial-diurnal time scales. Cross slope momentum and temperature fluxes have significant contributions from this frequency band. Collocated turbulent kinetic energy dissipation and temperature variance dissipation estimates imply a dissipation ratio of 0.14 that is not sensibly different from canonical values for shear instability (0.2). This mixing signature is associated with production in the internal wave band rather than frequencies associated with turbulent shear production. Our results reveal that the expectation of a quasi-stationary response to quasi-stationary forcing in the guise of eddy variability is naive and a boundary layer structure that does not support recent theoretical assumptions concerning one-dimensional models of boundary mixing.
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Kiciński, Radosław, Bogdan Szturomski, and Wojciech Jurczak. "Determination of Material Characteristics Necessary for Modelling of Marine Structures Exposed to Small-Calibre Bullet." Journal of KONES 26, no. 4 (December 1, 2019): 105–11. http://dx.doi.org/10.2478/kones-2019-0096.
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AbstractThe article presents the results of tests of impact properties of steel 1.3964 used on the construction of modern mine destroyers. Ships of this type, like any other military unit, may be exposed to small-calibre projectiles. Firing can be done, for example, from aircraft, drones or pirate units. The thickness of the plates used in the ship’s construction does not guarantee effective resistance to the projectile calibre 7.62 mm for all compartments of such ships. Thus, it is possible to modify the existing structure or apply additional solutions that will ensure a certain level of ballistic resistance. Solutions of this type are necessary in order to maintain the stability and buoyancy of the ship at the current level. During the tests, a stress-strain curve for steel 1.3964 was obtained, then the Johnson-Cook plasticity and damage model was proposed, which was used in the FEM simulation. The task was modelled as non-linear considering the deformation of both the sample and the projectile. The simulation was prepared in the CAE program, and then verified by an experiment on the shooting range. The results were presented in the form of diagrams and deformation figures, and were compared with photographs of samples and velocities after the specimen.
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Moura, Orilda M., Daniel A. Marinho, Jorge E. Morais, Mafalda P. Pinto, Luís B. Faíl, and Henrique P. Neiva. "Learn-to-swim program in a school context for a twelve-week period enhance aquatic skills and motor coordination in Brazilian children (Las clases de natación en el contexto escolar durante un período de doce semanas mejoran las habilidades acuáticas y l." Retos 43 (July 19, 2021): 316–24. http://dx.doi.org/10.47197/retos.v43i0.88903.
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This study aimed to verify the effects of 12 weeks of swimming lessons implemented in age school Brazilian children’s aquatic skills and motor coordination. Fifty children aged 6 to 10 years old (mean ± SD: 8.34 ± 1.10 years), participated in one swimming lesson per week provided by the school curriculum. Each child was evaluated for their aquatic skills (17 skills checklist) and motor coordination (Körperkoordinationstest Für Kinder test–KTK) before and after the swimming program. This study showed significant improvements in the sum of scores obtained in swimming skills evaluation (31.40 ± 12.89 vs. 46.90 ± 10.73 points, p < .01, d = 3.38). Large effects were found in water orientation and adjustment at the vertical position, breath control, horizontal buoyancy, body position at ventral, dorsal gliding and at longitudinal rotation, front and back somersaults, leg kicking with breath control, feet-first/head-first entries, autonomy in a deep pool and vertical buoyancy and immersion at deep water. The sum of scores in motor coordination assessment increased from 140.64 ± 41.94 to 175.20 ± 41.39 points (p < .01, d = 1.56). These results showed that 12 weeks of swimming practices, even conditioned by state school context (i.e., once a week), allowed Brazilian children aged 6-10 years old to increase aquatic skills and motor coordination.
Resumen. Este estudio tuvo como objetivo verificar los efectos de las clases de natación durante un período de 12 semanas en las habilidades acuáticas y la coordinación motora en niños brasileños. Cincuenta niños entre los 6 y los 10 años de edad (media ± DE: 8.34 ± 1.10 años) participaron una vez por semana en una clase de natación ofrecida por el plan de estudios escolar. Cada niño fue evaluado en cuanto a sus habilidades acuáticas (lista de verificación de 17 habilidades) y coordinación motora (Körperkoordinationstest Für Kinder test - KTK) antes y después del programa de natación. Los resultados del estudio mostraron mejoras significativas en la suma de las puntuaciones obtenidas en la evaluación de las habilidades de natación (31.40 ± 12.89 frente a 46.90 ± 10.73 puntos, p < .01, d = 3.38). Se observaran efectos importantes en la orientación y el ajuste del agua en la posición vertical, en el control de la respiración, en la flotabilidad horizontal, en la posición del cuerpo en la posición ventral, en el deslizamiento dorsal y la rotación longitudinal, en los saltos mortales hacia adelante y hacia atrás, en los empujes con las piernas con control de la respiración, pies primero / cabeza primero entradas, en la autonomía en piscina profunda y flotabilidad vertical y inmersión en aguas profundas. La suma de las puntuaciones en la evaluación de la coordinación motora aumentó de 140.64 ± 41.94 a 175.20 ± 41.39 puntos (p < .01, d = 1.56). Estos resultados mostraron que 12 semanas de prácticas de natación, incluso condicionadas por el contexto de la escuela estatal (es decir, una vez por semana), permitieron a los niños brasileños de 6 a 10 años aumentar de forma significativa la preparación acuática y la coordinación motora.
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Oh, Se Jun, and Sang Heon Lee. "Comparing durability of water- and land-based exercise benefits among older adults in South Korea: A randomized controlled trial with 1-year follow-up." Journal of Back and Musculoskeletal Rehabilitation 34, no. 5 (September 6, 2021): 745–55. http://dx.doi.org/10.3233/bmr-200109.
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BACKGROUND: Aquatic exercise can improve strength, flexibility, and aerobic function while safely providing partial weight-bearing support through viscosity and buoyancy. OBJECTIVE: The aim of the present study was to compare the effects of water-based exercise with land-based exercise before and after a 10-week exercise intervention and again at one-year follow-up. METHODS: Eighty participants aged 65 years and older were randomly assigned to either a water- or a land-based 10-week exercise program. Assessment included the Senior Fitness Test (SFT), the Modified Falls-Efficacy Scale, and the 36-Item Short-Form Health Survey (SF-36). Hip and knee strength was also measured. All assessments were completed at three time points: pre- (T1), post- (T2), and at 1-year follow-up (T3). RESULTS: Significant differences were observed between the two groups on three parameters: the SFT timed up-and-go test; lower hip muscle strength in extension, adduction, and external rotation; and quality of life (QoL) measured by the SF-36 (p< 0.05). No significant differences were observed in the SFT chair stand test, dominant arm curl test, two-minute step test, chair sit-and-reach test, back scratch test, and Modified Falls-Efficacy Scale. CONCLUSION: Aquatic exercise provided greater improvement of physical health and QoL among older people than land-based exercise.
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Zheng, Youtong, Daniel Rosenfeld, and Zhanqing Li. "Satellite Inference of Thermals and Cloud-Base Updraft Speeds Based on Retrieved Surface and Cloud-Base Temperatures." Journal of the Atmospheric Sciences 72, no. 6 (May 27, 2015): 2411–28. http://dx.doi.org/10.1175/jas-d-14-0283.1.
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Abstract Updraft speeds of thermals have always been difficult to measure, despite the significant role they play in transporting pollutants and in cloud formation and precipitation. In this study, updraft speeds in buoyancy-driven planetary boundary layers (PBLs) measured by Doppler lidar are found to be correlated with properties of the PBL and surface over the Southern Great Plains (SGP) site operated by the U.S. Department of Energy’s Atmospheric Radiation Measurement Program (ARM). Based on the relationships found here, two approaches are proposed to estimate both maximum (Wmax) and cloud-base (Wcb) updraft speeds using satellite data together with some ancillary meteorological data of PBL depth, wind speed at 10-m height, and air temperature at 2-m height. The required satellite input data are cloud-base and surface skin temperatures. PBL depth can be determined by using cloud-base temperature in combination with European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis data. Validation against lidar-measured updraft speeds demonstrated the feasibility of retrieving Wmax and Wcb using high-resolution Suomi–National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite (Suomi-NPP VIIRS) measurements over land for PBLs with thermally driven convective clouds during the satellite overpass time. The root-mean-square errors (RMSE) of Wmax and Wcb are 0.32 and 0.42 m s−1, respectively. This method does not work for a stable or a mechanically driven PBL.
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Suhas, E., and Guang J. Zhang. "Evaluation of Trigger Functions for Convective Parameterization Schemes Using Observations." Journal of Climate 27, no. 20 (October 7, 2014): 7647–66. http://dx.doi.org/10.1175/jcli-d-13-00718.1.
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Abstract Realistic simulation of different modes of atmospheric variability ranging from diurnal cycle to interannual variation in global climate models (GCMs) depends crucially on the convection trigger criteria. In this study, using the data from constrained variational analysis by the Atmospheric System Research program for single-column models (SCM), the performance of the commonly used convective trigger functions in GCMs is evaluated based on the equitable threat score (ETS) value, a widely used forecast verification metric. From the ETS score, three consistently better-performing trigger functions were identified. They are based on the dilute and undilute convective available potential energy (CAPE) generation rate from large-scale forcing in the free troposphere (hereafter dCAPE) and parcel buoyancy at the lifting condensation level (Bechtold scheme). The key variables used to define these trigger functions are examined in detail. It is found that the dilute dCAPE trigger function performs the best consistently in both the tropical and midlatitude convective environment. Analysis of the composite fields of key variables of the trigger functions, based on the correct prediction, overprediction and underprediction of convection, and correct prediction of no-convection cases for convective onset, brings to light some critical factors responsible for the performance of the trigger functions. The lower-tropospheric advective forcing in dilute dCAPE trigger and vertical velocity in Bechtold trigger are identified to be the most importance ones. Suggestions are offered for further improvements.
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Gibbs, Jeremy A., Evgeni Fedorovich, and Alexander M. J. van Eijk. "Evaluating Weather Research and Forecasting (WRF) Model Predictions of Turbulent Flow Parameters in a Dry Convective Boundary Layer." Journal of Applied Meteorology and Climatology 50, no. 12 (December 2011): 2429–44. http://dx.doi.org/10.1175/2011jamc2661.1.
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AbstractWeather Research and Forecasting (WRF) model predictions using different boundary layer schemes and horizontal grid spacings were compared with observational and numerical large-eddy simulation data for conditions corresponding to a dry atmospheric convective boundary layer (CBL) over the southern Great Plains (SGP). The first studied case exhibited a dryline passage during the simulation window, and the second studied case was used to examine the CBL in a post-cold-frontal environment. The model runs were conducted with three boundary layer parameterization schemes (Yonsei University, Mellor–Yamada–Janjić, and asymmetrical convective) commonly employed within the WRF model environment to represent effects of small-scale turbulent transport. A study domain was centered over the Atmospheric Radiation Measurement Program SGP site in Lamont, Oklahoma. Results show that near-surface flow and turbulence parameters are predicted reasonably well with all tested horizontal grid spacings (1, 2, and 4 km) and that value added through refining grid spacing was minimal at best for conditions considered in this study. In accord with this result, it was suggested that the 16-fold increase in computing overhead associated with changing from 4- to 1-km grid spacing was not justified. Therefore, only differences among schemes at 4-km spacing were presented in detail. WRF model predictions generally overestimated the contribution to turbulence generation by mechanical forcing over buoyancy forcing in both studied CBL cases. Nonlocal parameterization schemes were found to match observational data more closely than did the local scheme, although differences among the predictions with all three schemes were relatively small.
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Kawaguchi, Yusuke, Shigeto Nishino, Jun Inoue, Katsuhisa Maeno, Hiroki Takeda, and Kazuhiro Oshima. "Enhanced Diapycnal Mixing due to Near-Inertial Internal Waves Propagating through an Anticyclonic Eddy in the Ice-Free Chukchi Plateau." Journal of Physical Oceanography 46, no. 8 (August 2016): 2457–81. http://dx.doi.org/10.1175/jpo-d-15-0150.1.
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AbstractThe Arctic Ocean is known to be quiescent in terms of turbulent kinetic energy (TKE) associated with internal waves. To investigate the current state of TKE in the seasonally ice-free Chukchi Plateau, Arctic Ocean, this study performed a 3-week, fixed-point observation (FPO) using repeated microstructure, hydrographic, and current measurements in September 2014. During the FPO program, the microstructure observation detected noticeable peaks of TKE dissipation rate ε during the transect of an anticyclonic eddy moving across the FPO station. Particularly, ε had a significant elevation in the lower halocline layer, near the critical level, reaching the order of 10−8 W kg−1. The ADCP-measured current displayed energetic near-inertial internal waves (NIWs) propagating via the stratification at the top and bottom of the anticyclone. According to spectral analyses of horizontal velocity, the waves had almost downward energy propagation, and its current amplitude reached ~10 cm s−1. The WKB scaling, incorporating vertical variations of relative vorticity, suggests that increased wave energy near the two pycnoclines was associated with diminishing group velocity at the corresponding depths. The finescale parameterization using observed near-inertial velocity and buoyancy frequency successfully reproduced the characteristics of observed ε, supporting that the near-inertial kinetic energy can be effectively dissipated into turbulence near the critical layer. According to a mixed layer slab model, a rapidly moving storm that has passed over in the first week likely delivered the bulk of NIW kinetic energy, eventually captured by the vortex, into the surface water.
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Vasilenko, V. N., L. N. Frolova, I. V. Dragan, N. A. Mihajlova, and S. I. Zhiltsova. "Development of industrial feed for channel catfish grown in the Central Federal District of the Russian Federation." Proceedings of the Voronezh State University of Engineering Technologies 82, no. 4 (January 20, 2021): 132–36. http://dx.doi.org/10.20914/2310-1202-2020-4-132-136.
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In the result of the analysis of domestic experience over the last 10 years of foreign experience (for example, 9 countries: Vietnam, India, Spain, Canada, China, Norway, USA, Chile, Japan, which possess the most advanced technologies and equipment for highly efficient production of feed for fish) in the development of innovative technologies and equipment for production of high-performance fish feeds were identified that the methods both dry and wet pressing are outdated and do not meet modern requirements in the production of fish feeds since it does not allow a deep physical-chemical transformations in protein-carbohydrate complex and exercise enter fat components at 40 %. Modern fish technologies are based on the use of extrusion processing of multicomponent mixture to give different buoyancy and adjustable rate of immersion of the resulting feed. Extrusion technology will allow to introduce a large amount of fat into the product - up to 35-40 %, to achieve 100 % starch splitting level. Based on the study of the nutrition of the canal catfish grown in the Central Federal District of the Russian Federation, the nutritional value of each of the components of the feed mixture, providing the need for fish to ensure a significant increase in the growth of live mass and improve the chemical composition of meat, was assessed for different age groups. To solve this problem, the "Feed Optima Expert" optimization program has developed products of extruded feed. Food needs of canal som: 30 - 40 percent protein, 4 - 6 percent fat, no more than 5 percent fiber, 35 - 40 percent Nosazotic Extract substances and 12 - 13 thousand kilos of Joule digestible energy in 1 kilogram (in recalculation on dry matter).
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Qu, Xiaobin, Yingxue Yao, and Jianjun Du. "Conceptual Design and Hydrodynamic Performance of a Modular Hybrid Floating Foundation." Energies 14, no. 22 (November 14, 2021): 7605. http://dx.doi.org/10.3390/en14227605.
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The comprehensive utilization of offshore renewable energies is an effective way to solve the intermittency and variability of power supply. This paper aims to present a hybrid floating system (HFS) based on a modular buoyancy-distributed floating foundation (BDFF) that can be equipped with a horizontal-axis wind turbine, solar panels, and wave energy converters (WEC). A simplified test model with a Froude scale ratio of 1/10 is employed to perform the experiments in a deep-water basin to validate the numerical results computed from the code program ANSYS AQWA based on the potential flow theory. The Response Amplitude Operators (RAOs) under regular waves are compared to evaluate the hydrodynamic performance. There is a good agreement in the surge, pitch, and heave RAOs for experiments and the numerical simulation, with a maximum of 6.45 degrees per meter for the pitch motion. Furthermore, the mooring tensions in the time domain are analyzed under different wave conditions.The tension RAOs from simulations are slightly higher than those from measurements with a maximum value at the period of 3.416 s. The mooring line on the windward side has a more considerable mooring tension that is far less than the allowable tensile strength, especially under the wave height of 2 m and the wave period of 2.873 s. The influence of loaded weight representing solar panels is weak, and the impact of winds is acceptable, as the platform deviates 1.3 degrees from the equilibrium state under the test wind speed. Eventually, the effect of irregular waves on the HFS is presented with the critical parameters of mooring tension and pitch motion. The results show that the HFS has a good motion performance.