scholarly journals Numerical Study of a Single-Point Mooring Gravity Fish Cage With Different Deformation-Suppression Methods

2019 ◽  
Author(s):  
Hui Cheng ◽  
Karl Gunnar Aarsæther ◽  
Lin Li ◽  
Muk Chen Ong
Keyword(s):  
Organic Matter ◽  
Numerical Study ◽  
Single Point ◽  
Local Environment ◽  
Manufacturing Cost ◽  
Volume Loss ◽  
Practical Advice ◽  
Rigid Frame ◽  
The One ◽  
Positive Effect

Abstract Compared to the multi-point mooring fish cage, the single point mooring (SPM) fish cage can spread out the accumulation of organic matter to prevent the local environment from being overwhelmed, and reduce the manufacturing cost at the same time. Thus, it has attracted many attentions recently. In this research, different deformation-suppression methods are applied to the SPM system with a typical Norwegian fish cage aiming to reduce the cultivation volume loss. A well-validated software, FhSim, is used to conduct the full-scale numerical study. The effects of the three deformation-suppression methods (i.e. (i) adding the lower bridles, (ii) adding the frontal rigid frame, (iii) adding the trawl door) are analyzed under pure current and combined wave-current conditions. The results indicate that all the three methods can reduce the cultivation volume loss at least by 32% compared to the one with the original SPM system when the current velocity is larger than 0.5 m/s. In addition, moving the conjunction point close to the bottom ring can bring positive effect in the cultivation volume maintaining with an unnoticeable increase in the tension force. This study will provide practical advice and useful guides for the SPM fish cage design.

scholarly journals Numerical Study of a Single-Point Mooring Gravity Fish Cage With Different Deformation-Suppression Methods

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Hui Cheng ◽  
Karl Gunnar Aarsæther ◽  
Lin Li ◽  
Muk Chen Ong
Keyword(s):  
Current Velocity ◽  
Numerical Study ◽  
Single Point ◽  
Local Environment ◽  
Full Scale ◽  
Tension Force ◽  
Wave Loads ◽  
Practical Advice ◽  
Rigid Frame ◽  
Positive Effect

Abstract Compared with the multipoint mooring fish cage, the single-point mooring (SPM) fish cage can spread out the fish wastes and uneaten feeds in a larger area, and it can also prevent the local environment from being overwhelmed. Thus, it has attracted much attention recently. In this research, different deformation-suppression methods are applied to the SPM system with a typical Norwegian fish cage aiming to increase the cultivation volume under the action of current and/or wave loads. A well-validated software, fhsim, is used to conduct the full-scale numerical study. The effects of the three deformation-suppression methods, i.e., (i) adding the lower bridles, (ii) adding the frontal rigid frame and (iii) adding the trawl doors, are analyzed under pure current and combined wave–current conditions. The results indicate that all the three deformation-suppression methods can improve the cultivation volume at least by 32% compared to the original SPM fish cage when the current velocity is larger than 0.5 m/s. In addition, moving the conjunction point close to the bottom ring can bring a positive effect on the cultivation volume maintaining with an only small increment in the tension force. This study can provide practical advice and useful guides for the SPM fish cage design.

scholarly journals Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4301
Author(s):  
Yassir A. Alamri ◽  
Saad Mahmoud ◽  
Raya Al-Dadah ◽  
Shivangi Sharma ◽  
J. N. Roy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Numerical Study ◽  
Single Point ◽  
Optical Element ◽  
Fresnel Lens ◽  
Electrical Performance ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Optical Efficiency ◽  
Concave Lens

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

On the numerical study of thermohydrodynamics and biochemistry of inland water bodies

2021 ◽  
Author(s):  
Daria Gladskikh ◽  
Evgeny Mortikov ◽  
Victor Stepanenko
Keyword(s):  
Mixed Layer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Water Bodies ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Lake Model ◽  
Upper Mixed Layer ◽  
The One

<p>The study of thermodynamic and biochemical processes of inland water objects using one- and three-dimensional RANS numerical models was carried out both for idealized water bodies and using measurements data. The need to take into account seiche oscillations to correctly reproduce the deepening of the upper mixed layer in one-dimensional (vertical) models is demonstrated. We considered the one-dimensional LAKE model [1] and the three-dimensional model [2, 3, 4] developed at the Research Computing Center of Moscow State University on the basis of a hydrodynamic code combining DNS/LES/RANS approaches for calculating geophysical turbulent flows. The three-dimensional model was supplemented by the equations for calculating biochemical substances by analogy with the one-dimensional biochemistry equations used in the LAKE model. The effect of mixing processes on the distribution of concentration of greenhouse gases, in particular, methane and oxygen, was studied.</p><p>The work was supported by grants of the RF President’s Grant for Young Scientists (MK-1867.2020.5, MD-1850.2020.5) and by the RFBR (19-05-00249, 20-05-00776). </p><p>1. Stepanenko V., Mammarella I., Ojala A., Miettinen H., Lykosov V., Timo V. LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes // Geoscientific Model Development. 2016. V. 9(5). P. 1977–2006.<br>2. Mortikov E.V., Glazunov A.V., Lykosov V.N. Numerical study of plane Couette flow: turbulence statistics and the structure of pressure-strain correlations // Russian Journal of Numerical Analysis and Mathematical Modelling. 2019. 34(2). P. 119-132.<br>3. Mortikov, E.V. Numerical simulation of the motion of an ice keel in stratified flow // Izv. Atmos. Ocean. Phys. 2016. V. 52. P. 108-115.<br>4. Gladskikh D.S., Stepanenko V.M., Mortikov E.V. On the influence of the horizontal dimensions of inland waters on the thickness of the upper mixed layer // Water Resourses. 2021.V. 45, 9 pages. (in press) </p>

scholarly journals Optimal Portfolios for Financial Markets with Wishart Volatility

2013 ◽  
Vol 50 (4) ◽  
pp. 1025-1043 ◽  
Author(s):  
Nicole Bäuerle ◽  
Zejing Li
Keyword(s):  
Value Function ◽  
Numerical Study ◽  
Heston Model ◽  
Hard Part ◽  
Control Approach ◽  
Portfolio Strategy ◽  
Hamilton Jacobi Bellman ◽  
The One ◽  
Hedging Demand ◽  
The Value Function

We consider a multi asset financial market with stochastic volatility modeled by a Wishart process. This is an extension of the one-dimensional Heston model. Within this framework we study the problem of maximizing the expected utility of terminal wealth for power and logarithmic utility. We apply the usual stochastic control approach and obtain, explicitly, the optimal portfolio strategy and the value function in some parameter settings. In particular, we do this when the drift of the assets is a linear function of the volatility matrix. In this case the affine structure of the model can be exploited. In some cases we obtain a Feynman-Kac representation of the candidate value function. Though the approach we use is quite standard, the hard part is to identify when the solution of the Hamilton-Jacobi-Bellman equation is finite. This involves a couple of matrix analytic arguments. In a numerical study we discuss the influence of the investors' risk aversion on the hedging demand.

Is There a Difference between the Effects of One-Point and Three-Point Indirect Moxibustion Stimulation on Skin Temperature Changes of the Posterior Trunk Surface?

2012 ◽  
Vol 30 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Hidetoshi Mori ◽  
Tim Hideaki Tanaka ◽  
Hiroshi Kuge ◽  
Ken Sasaki
Keyword(s):  
Skin Temperature ◽  
Single Point ◽  
Indirect Moxibustion ◽  
Thermal Stimulation ◽  
Acupuncture Points ◽  
Lumbar Region ◽  
Temperature Changes ◽  
Posterior Trunk ◽  
The One ◽  
Stimulation Group

Objective To determine whether any difference exists in responses to indirect moxibustion relative to thermal stimulation sites. Methods Twenty one healthy men of mean±SD age 22.5±6.1 years were randomly divided into two groups, one receiving a single moxibustion stimulation in three locations (the three-point stimulation group, n=10 participants) and the other receiving three stimulations in one location (the one-point stimulation group, n=11 participants). The thermal stimulation sites were GV14, GV9 and GV4 acupuncture points. A thermograph was used to obtain the skin temperature on the posterior trunks of the participants. To analyse skin temperature, four arbitrary frames (the scapular, interscapular, lumbar and vertebral regions) were made on the posterior trunk. Result An increase in skin temperature on the posterior trunk was observed following both one- and three-point moxibustion administrations. The skin temperature of the lumbar region showed a significant increase after three-point stimulation compared with single-point stimulation (p=0.011). There was also a significant increase in skin temperature of the spinal region after three-point stimulation compared with one-point stimulation (p=0.046). Conclusion Administration of single moxibustion doses on the GV14, GV9 and GV4 points produces greater changes in skin temperature than three applications of moxibustion to the GV14 point only.

Experimental and Numerical Study of Honeycomb Tip on Suppressing Tip Leakage Flow in Turbine Cascade

2017 ◽  
Author(s):  
Yunfeng Fu ◽  
Fu Chen ◽  
Huaping Liu ◽  
Yanping Song
Keyword(s):  
Numerical Study ◽  
Flow Characteristics ◽  
Leakage Flow ◽  
Exit Section ◽  
Turbine Cascade ◽  
Tip Leakage Flow ◽  
Physical Processes ◽  
Tip Leakage ◽  
Gap Height ◽  
Positive Effect

In this paper, the effect of a novel honeycomb tip on suppressing tip leakage flow in a highly-loaded turbine cascade has been experimentally and numerically studied. The research focuses on the mechanisms of honeycomb tip on suppressing tip leakage flow and affecting the secondary flow in the cascade, as well as the influences of different clearance heights on leakage flow characteristics. In addition, two kinds of local honeycomb tip structures are pro-posed to explore the positive effect on suppressing leakage flow in simpler tip honeycomb structures. Based on the experimental and numerical results, the physical processes of tip leakage flow and its interaction with main flow are analyzed, the following conclusions can be obtained. Honeycomb tip rolls up a number of small vortices and radial jets in regular hexagonal honeycomb cavities, increasing the flow resistance in the clearance and reducing the velocity of leakage flow. As a result, the structure of honeycomb tip not only suppresses the leakage flow effectively, but also has positive effect on reducing the associated losses in cascade by reducing the strength of leakage vortex. Compare to the flat tip cascade at 1%H gap height, the relative leakage flow in honeycomb tip cascade reduces from 3.05% to 2.73%, and the loss at exit section is also decreased by 10.63%. With the increase of the gap height, the tip leakage flow and loss have variations of direct proportion with it, but their growth rates in the honeycomb tip cascade are smaller. Consider the abradable property of the honeycomb seal, a smaller gap height is allowed in the cascade with honeycomb tip, and that means honeycomb tip has better effect on suppressing leakage flow. Two various local honeycomb tip structures has also been discussed. It shows that local raised honeycomb tip has better suppressing leakage flow effect than honeycomb tip, while local concave honeycomb tip has no more effect than honeycomb tip. Compare to flat tip cascade, the leakage flow in honeycomb tip cascade, local concave tip cascade and local raised honeycomb tip cascade decrease by nearly 17.33%, 15.51% and 30.86% respectively, the losses at exit section is reduced by 13.38%, 12% and 28.17% respectively.

scholarly journals EVALUATION OF THREE SURFACE FRICTION TECHNIQUES FOR THE REMOVAL OF ORGANIC MATTER

2015 ◽  
Vol 24 (4) ◽  
pp. 1061-1070 ◽  
Author(s):  
Marcelo Alessandro Rigotti ◽  
Adriano Menis Ferreira ◽  
Mara Corrêa Lelles Nogueira ◽  
Margarete Teresa Gottardo de Almeida ◽  
Odanir Garcia Guerra ◽  
...  
Keyword(s):  
Organic Matter ◽  
Adenosine Triphosphate ◽  
Organic Material ◽  
Surface Friction ◽  
Disinfection Process ◽  
Significant Difference ◽  
Before And After ◽  
Quantitative Descriptive ◽  
The One ◽  
Cleaning And Disinfection

ABSTRACT The objective of this study was to assess the effectiveness of three surface friction techniques for the removal of organic material. A quantitative, descriptive and exploratory study was developed to evaluate the presence or not of organic material before and after the cleaning and disinfection process of surfaces of bedside tables of patients hospitalized at an Intensive Care Unit. Three friction techniques were executed in the one-way, two-way and centrifugal sense, individually, three times on each table, during alternate weeks. For each patient unit and friction technique, a single table and three sides of cloth were used, moistened with 70% (w/v) alcohol. The organic matter was detected through the presence of adenosine triphosphate by bioluminescence, using 3M(tm) Clean-Trace(tm) ATP Systems. For each technique, 13 samples were collected before and 13 after the cleaning/disinfection process, totaling 78 samples of adenosine triphosphate by bioluminescence. No statistically significant difference was found among the removal techniques of organic matter. This study demonstrated that none of the three surface friction methods was better than the other to remove organic matter. Nevertheless, further research is needed in which other cleaning/disinfection indicators and surfaces are considered.

scholarly journals A Study of the Closed-Loop Supply Chain Coordination on Waste Glass Bottles Recycling

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Wenxue Ran ◽  
Fan Chen ◽  
Qianni Wu ◽  
Sen Liu
Keyword(s):  
Supply Chain ◽  
Closed Loop ◽  
Numerical Study ◽  
Supply And Demand ◽  
Waste Glass ◽  
Manufacturing Cost ◽  
Single Node ◽  
Closed Loop Supply Chain ◽  
Waste Products ◽  
Glass Bottles

The recycling of waste products can sharply save manufacturing cost and improve the economic efficiency and corporate-reputation. It also has a great effect on the environment and resources protection. In the management of the closed-loop supply chain, the recycling of waste products and decision-making on pricing often directly affect the supply and demand of products and the operation efficiency of supply chain. Therefore, first we take waste glass bottles as an example and establish a mathematical model to solve the profit of manufacturers and retailers solely. Then, we analyzed whole supply chain profit under a dual-channel recycling condition which is directly recycled by consumers or by retailers. Finally, we concluded that no matter what product’s price, quality, profit, or operational efficiency of supply chain is, the overall recycling is better than the single node recycling model. Based on the analysis, we developed a new model to coordinate the profit of manufacturers and retailers in the supply chain with revenue-sharing contract. A numerical study shows that this approach is applicable and effective.

scholarly journals On the optimal control force applied to tuned mass dampers for multi-degree-of-freedom systems

2004 ◽  
Vol 26 (1) ◽  
pp. 1-10
Author(s):  
Nguyen Dong Anh ◽  
Nguyen Chi Sang
Keyword(s):  
Optimal Control ◽  
Numerical Study ◽  
Degree Of Freedom ◽  
Control Force ◽  
Linear Quadratic ◽  
Tuned Mass Dampers ◽  
Coloured Noise ◽  
Optimal Theory ◽  
The One ◽  
Better Than

The design of active TMD for multi-degree-of-freedom systems subjected to second order coloured noise excitation is considered using the linear quadratic optimal theory. A detailed numerical study is carried out for a 2-DOF system. It is shown that the effectiveness of active TMD is better than the one of passive TMD.

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