Cage Volume Research Articles

Numerical Modelling of Fish Cage Structural Responses in Regular and Irregular Waves Using Modified XPBD

Abstract The structural response of gravity-type fish cages in waves and current is numerically investigated. A Morison model is adopted to compute the hydrodynamic forces acting on the net ropes of the aquaculture nets and a screen model is used to compute the hydrodynamic forces on the net twines of the fish cages. The irregular waves are created based on the JONSWAP wave spectrum. The structure of the aquaculture nets is modeled using a modified extended position-based dynamics (XPBD) algorithm. The proposed method is effectively validated against the published experiment data to ensure its accuracy and reliability. The static response of the fish cage at various current speeds and the dynamic responses of the fish cage in regular and irregular waves are analyzed. Results show that the volume of the investigated fish cage is reduced by 30% in a current of 0.5m/s. The tension at the bottom net can reach about five times of maximum tension of the case without current. In the regular or irregular waves, the drag force of the fish cage is higher than that in a uniform flow with the same current speed and the fish cage volume decreases. The increase in drag force rises from the coupling between the waves and current. Therefore, the hydrodynamic model including the regular and irregular modeling, Morison model and screen model is successfully implemented into the framework of the present modified XPBD algorithm to provide the structural response of fish cages in waves and current.

Holistic shape variation of the rib cage in an adult population.

Traumatic injuries to the thorax are a common occurrence, and given the disparity in outcomes, injury risk is non-uniformly distributed within the population. Rib cage geometry, in conjunction with well-established biomechanical characteristics, is thought to influence injury tolerance, but quantifiable descriptions of adult rib cage shape as a whole are lacking. Here, we develop an automated pipeline to extract whole rib cage measurements from a large population and produce distributions of these measurements to assess variability in rib cage shape. Ten measurements of whole rib cage shape were collected from 1,719 individuals aged 25-45years old including angular, linear, areal, and volumetric measures. The resulting pipeline produced measurements with a mean percent difference to manually collected measurements of 1.7% ± 1.6%, and the whole process takes 30s per scan. Each measurement followed a normal distribution with a maximum absolute skew value of 0.43 and a maximum absolute excess kurtosis value of 0.6. Significant differences were found between the sexes (p < 0.001) in all except angular measures. Multivariate regression revealed that demographic predictors explain 29%-68% of the variance in the data. The angular measurements had the three lowest R2 values and were also the only three to have little correlation with subject stature. Unlike other measures, rib cage height had a negative correlation with BMI. Stature was the dominant demographic factor in predicting rib cage height, coronal area, sagittal area, and volume. Subject weight was the dominant demographic factor for rib cage width, depth, axial area, and angular measurements. Age was minimally important in this cohort of adults from a narrow age range. Individuals of similar height and weight had average rib cage measurements near the regression predictions, but the range of values across all subjects encompassed a large portion of their respective distributions. Our findings characterize the variability in adult rib cage geometry, including the variation within narrow demographic criteria. In future work, these can be integrated into computer aided engineering workflows to assess the influence of whole rib cage shape on the biomechanics of the adult human thorax.

Investigation of hydrogen uptake capacity for FAU, MOR, MTW, MWW

In this study, the hydrogen storage properties of various synthetic zeolites, including Zeolite Y (FAU), Mordenite (MOR), ZSM-12 (MTW), and MCM-22 (MWW) are determined at 77 K and atmospheric pressure. The structures of the zeolites are characterized by XRD, ICP-OES, FE-SEM, TGA and N2 adsorption-desorption isotherms. The results show that H-MCM-22 zeolite has the highest hydrogen storage capacity at 1.0 bar with 1.19 wt%, followed by H-MOR zeolite with 1.05 wt%, H–Y zeolite with 0.75 wt% and H-ZSM-12 zeolite with 0.60 wt%. The hydrogen adsorption data on FAU, MOR, MTW, and MWW at 77 K obey the Sips isotherm model. The experimental data show that the ultra-micropore volume of the zeolite is effective in hydrogen adsorption at low-pressure ranges. In addition, increasing the aluminum content of the zeolite increases the hydrogen adsorption capacity of the zeolite at atmospheric pressure. Therefore, zeolites with channel sizes close to the kinetic diameter of a hydrogen molecule, large cage volumes, and high aluminum content are potential candidates for energy storage applications.

Design and analysis of grid mooring system for gravity net cage with a comprehensive optimization method

The design of gravity net cage mooring systems is a complex endeavor, which is critical for preventing major accidents caused by mooring system failures. A comprehensive optimization method is proposed to enhance the reliability and performance of the net cage mooring system by integrating static and dynamic phases. The proposed method initiates static simulations based on the catenary theory to refine the initial range of parameters. This preparatory step ensures the subsequent dynamic analysis is carried out based on feasible initial conditions with the lumped mass method. The dynamic simulation captures the complex interactions and behavior of the mooring systems under various environmental conditions. The multi-objective optimization provides feasible solutions with simultaneous consideration of both processes. Three different scenarios are optimized with the forces and motions compared after the time domain analysis, resulting in a satisfactory set of solutions. The results show that variations in the angle of the mooring line of the net cage primarily impact the net cage's movement and volume in different environments.

Numerical Simulation of Net Cage and an Alternative Method to Estimate the Remaining Volume

Abstract The deformation caused by waves and current in an aquatic environment significantly impacts the remaining volume of a net cage. Its fluctuations in magnitude could pose a potential threat to the well-being of cultivated species. There is a critical need for a simple, cost-effective solution to monitor cage deformation in real-time. This study proposes a depth-based method, utilizing just two depth meters attached to the cages floating collar and tube sinker, to estimate the remaining volume. Compared to the experimental measurements from previous studies, this method demonstrates satisfactory accuracies. Under current-only and waves-current conditions, the estimation differences are around 11.6% and 23%, respectively. In contrast, when compared to commonly used volume-based methods, the differences are approximately 1.8% and 9.5%. Despite a tendency for overestimation when the mean cross-sectional area deviates from the original top or bottom area of the cage, this method remains a feasible alternative. Its practicality highlights its potential as an efficient means of monitoring cage deformation.

Uncertainty Assessment of the Remaining Volume of an Offshore Gravity Fish Cage

The volume of a gravity cage is greatly reduced under a current due to the flexible structure, which affects the growth and health of the fish. Thus, an accurate assessment of cage volume is essential to determine the number of fishes in the cage. In this study, firstly, a numerical model was built to study the cage volume reduction of gravity cages due to the flexible net deformation when subjected to uniform flow. The remaining volume was calculated and compared with earlier experiments. Even though the flow velocity reductions were considered according to the data from previous experiments, the differences between the results from the numerical calculation and the towing tests are still significant. The physical model tests were treated as the reference value to investigate the uncertainty of the model results. Both the velocity-independent model error and velocity-dependent model error were calculated. With the help of the error models, the uncertainty of the remaining volume can be predicted. In addition, the velocity-dependent model error performs better in evaluating the uncertainty of the numerical calculation of the remaining culturing volume. Overall, the results show that the numerical model assisted by the model errors can calculate the cage volume accurately.

Fluid–Structure Interactions of Net Cages—Full-Scale Pushing Tests in the Field

Abstract This paper presents field tests on a full-scale cage, with and without fish, being pushed by a boat in Masfjorden at various speeds. The purpose was to imitate the exposure of net cages to different currents. The tests involved measuring cage deformations, fish behaviors, and the corresponding flow upstream, downstream, and inside the cage. The study found that the experimental setup used can achieve predictable and stable upstream flow for a full-scale net cage. Based on pressure tag data, the volume reductions of the cage, both with and without fish, were estimated at different speeds. Both cases show a similar trend of cage volume reduction with respect to flow speeds as the previous studies. Moreover, the presence of fish had limited the influence on the net volume change. The reduction in speed inside and downstream from the cage was within the range reported in previous literature. Notably, when the cage becomes significantly deformed, it not only reduces flow speed but also alters flow directions, as evidenced by the high variability of flow direction inside the empty cage, particularly at high speeds. The measured flow speed inside the stocked cage also exhibited high variability, but the pattern of variation differed significantly from that of the empty cage, indicating the influence of fish. These findings suggest that traditional flow speed models might oversimplify the flow field in and around fish cages, especially in studies concerning the dispersion of particles, pathogens, and dissolved matter in and out of fish cages.

Atomistic Investigation of the occupancy limits and stability of hydrogen hydrates as a hydrogen storage medium

Gas hydrates are nonstoichiometric inclusion compounds which occur via a hydrogen bonded water network. This network forms cages that encapsulates gas molecules such as hydrogen which are stabilized by weak van der Waals forces. This unique cage-guest interaction offers the potential for a safe, economical, and green medium for hydrogen storage. In this study, we use Density Functional Theory (DFT) to investigate the storage capacity of hydrates which primarily depends on the hydrogen occupancy in the small and large cages of the lattice structure. Energy analysis of the system with various occupancies shows that DFT is indicating occupancy limits beyond what has been previously reported and that the maximum occupancy in small and large cages is interdependent. The maximum hydrogen occupancy is 9 in large cages with an occupancy of 1 and 2 in the small cages and a maximum of 8 with an occupancy of 3 or 4 in the small cages. The occupancy limit mechanism is the breakage of hydrogen bonds due to cage volume expansion, the diffusion of hydrogen through pentagonal and hexagonal faces in small and large cages, and computational convergence.

Sensitivity analysis of the cage volume and mooring forces for a gravity cage subjected to current and waves

A numerical model is developed to calculate the mooring forces and cage volumes for a gravity cage system. The collar, nets, bottom ring and mooring system are all modelled by line elements due to the slender structure. The effect of structural parameters on the cage capacity and mooring forces is evaluated in a sensitivity analysis, to provide knowledge in the design phase of a fish cage. Heaver sinkers and nets with smaller solidity are preferred to prevent the volume reduction of fish cages but they lead to a larger mooring force or an increase in the probability of fish escaping. Linear wave theory is applied. Short waves increase the mean value of the mooring force and higher waves result in a larger amplitude of the mooring force. It is also found that short waves can change the shape of the nets while the shape of the cage subjected to long waves almost keeps constant as the one under uniform flow, which obtains a good agreement as previous experiments.

Theoretical analysis of substituent- and cage-dependent electronic properties of POSS

Polyhedral Oligomeric Silsesquioxanes (POSS) molecules have emerged as promising alternatives to traditional silica nanoparticles and organosilicon molecules due to their ability to attach a variety of substituents to their central siloxane cages. The electronic features of POSS are dependent on the structures of substituents and cages, making them attractive for applications, such as drug nanocarriers, chemosensors, Janus particles, and inorganic–organic nanocomposites. However, the lack of detailed geometric data poses a difficulty in extending POSS studies using the force field method or beyond the quantum mechanical level. To lay a foundation for future experimental and computational studies, we present new theoretical insights into the influence of substituent and cage on the cage geometries (Si–O bond length, pore width, cage volume, etc.) of 16 substituted POSS molecules with various substituents and cages (T7, T8, T10, T12). Our results show that the mean Si–O bond length of the POSS cage can be in the range of 1.619–1.670 Å depending on the substituent and cage. Moreover, we show that the expansion or shrinkage of POSS depends on the types of substituents, rather than the inductive effect of substituents. Our results demonstrate that the conformational stability, dipole moment, and polarizability of POSS depend on the substituents’ size, substituents’ shape, type of functional moieties of substituents, and cage size. In addition, the HOMO-LUMO bandgap of POSS can be tuned by changing the hydrocarbon chain length, number of aromatic rings, and types of functional groups on the substituents. Finally, we report several sets of geometric data that are transferable to the existing parametrization methods of force field models.

Comparative study of spread and vertical mooring configuration in floating collar net cage under irregular waves and current

Offshore aquaculture is one of the national strategic programs of the Ministry of Fishery and Ocean Affairs of Indonesia to increase national fish cultivation capacity. One solution is using a simple flexible floating collar net which is suitable for small to medium cage volume. In designing such floating net, its mooring line configuration is vital to maintain fixed position of structural part of the cage volume. The purpose of this study is to compare design aspect of two types of mooring systems, i.e., spread and vertical configuration, by investigating selected parameters: mooring line tension, collar offset, and volume reduction. The mooring configuration and floating collar net cage are analysed through a numerical model based on Morison-force equations, under environmental condition adopted from Kangean field East Java. Load cases from collinearly in-line and between-line directions under extreme waves and current condition are checked against relevant safety factor. The dynamics analysis using the time domain simulation is based on 900 seconds cut-off according to its maximum wave elevation profile to generate the hydrodynamics forces to the mooring systems.

P201 Comparison of high-resolution computed tomography chest volume and lung volume measured by body plethysmography in adult patients with cystic fibrosis

The aim of this study was to compare high-resolution computed tomography (HRCT) thoracic cage volume and lung volume measured by body plethysmography in adult patients with cystic fibrosis (CF), and to identify parameters that influence the difference between measurements (Dvol = VHRCT-VPFT).

Rapid ammonia build-up in small individually ventilated mouse cages cannot be overcome by adjusting the amount of bedding

We sought to investigate if varying levels of bedding had an effect on intra-cage ammonia levels in individually ventilated mouse cages (Euro Standard Types II and III). Employing a routine 2 week cage-changing interval, our goal is to keep ammonia levels under 50 ppm. In smaller cages used for breeding or for housing more than four mice, we measured problematic levels of intra-cage ammonia, and a considerable proportion of these cages had ammonia levels at more than 50 ppm toward the end of the cage-change cycle. These levels were not reduced significantly when the levels of absorbent wood chip bedding was either increased or decreased by 50%. The mice in both cage types II and III were housed at comparable stocking densities, yet ammonia levels in larger cages remained lower. This finding highlights the role of cage volume, as opposed to simply the floor space, in controlling air quality. With the current introduction of newer cage designs that employ an even smaller headspace, our study urges caution. With individually ventilated cages, problems with intra-cage ammonia may go undetected, and we may opt to utilize insufficient cage-changing intervals. Few modern cages have been designed to account for the amounts and types of enrichment that are used (and, in parts of the world, mandated) today, adding to the problems associated with decreasing cage volumes.

Respiratory Function Assessment through Kinematic Analysis of Chest Wall Movements: Effects of Position and Gender.

The effect of position and gender on chest movements and respiratory volumes is controversial and investigated in only a few studies. This study aimed to investigate the effects of position and gender on the breathing pattern during four different positions in healthy individuals. In this cross-sectional study, twenty-eight (14 males, 14 females) healthy individuals participated aged 20-45 years. The optoelectronic plethysmography (OEP) method was used for the three-dimensional evaluation of chest wall motions and the compartmental analysis of the breathing pattern in supine, sitting, standing, and active straight leg raised (ASLR) positions. Volume changes in different parts of the chest wall were also measured. Position affected total and compartmental respiratory volumes in both genders. Respiratory volumes decreased in the supine position compared to sitting and standing. Total and abdominal respiratory volumes also decreased in females when comparing supine positions with the ASLR. A higher pulmonary rib cage contribution was identified in females, and males exhibited higher abdominal rib cage volume compared with females. The breathing pattern was affected by position and gender, and the respiratory volumes increased in more upright positions, perhaps due to a greater gravitational load. The ASLR decreases the respiratory volume, which is probably due to increased postural demand.

Experimental and numerical studies on successive failures of two mooring lines of a net cage subjected to currents

This study investigates the hydrodynamic changes due to successive failures of two mooring lines on a net cage that are subjected to currents using model tests and numerical simulations. An eight-point mooring net-cage model with two electromagnets, which are used to disconnect its upstream mooring lines, is installed in a water flume. The experiment is conducted to measure the lateral mooring forces, rigid-body motions, and remaining volume of the net cage under successive mooring-failure conditions. To reduce the experimental difficulty, successive failures of the mooring lines are forced to occur at 10 and 30 s after the beginning of measurement. A numerical simulation, which is specifically designed for the model test, is also conducted. The results reveal that as the second upstream mooring line fails, the mooring load of the lateral lines, vertical and horizontal movements of the floating collar and tube sinker, and remaining volume of the net cage obviously increase. The values are much larger than those at the first upstream-line failure. The yaw motion of the floating collar increases as the first failure occurs, but it reverts to its origin after the second failure. Comparison of the simulation and experimental results shows good agreement in terms of the mooring force, especially for velocities less than 20 cm/s. The numerical simulations of the body motions of the floating collar and tube sinker and the remaining volume of the net cage are also similar to the experimental results. However, the simulation results of the motion response of the floating collar and the tube sinker after the second failure are obviously smaller than the experimental results.

Effect of cage size on oxygen levels in Atlantic salmon sea cages: A model study

The supply of dissolved oxygen (DO) to salmon in sea cages depends on many interacting factors including biomass density, temperature and current speed. With other factors being equal, hypoxic conditions are more likely to arise in large cages compared to small. In this work, a mathematical model of DO in sea cages is used to analyse the effect of horizontal cage size in particular. It is shown and quantified how the DO level at key locations in the cage depend on cage radius and current speed, and the fraction of the cage volume with hypoxic conditions is estimated as a function of cage radius, current speed and temperature.The results of this study give new insight into how oxygen conditions are affected when cage size is scaled up or down. Although conditions at actual aquaculture sites are highly variable and complex, the results can help forecast the effect of increasing cage size at existing sites, and can help guide the planning of new production sites with regard to oxygen supply.

Hydrodynamic origin for the suspension viscoelasticity of rough colloids

We report the linear rheology for dense suspensions of sterically stabilized smooth and mesoscopically rough colloids interacting as hard particles. Small amplitude oscillatory measurements reveal that rough colloids at high volume fractions exhibit storage and loss moduli that are orders of magnitude greater than smooth colloids. Frequency-concentration superposition is used to collapse the viscoelasticity data onto a master curve, where shift factors suggest a more elastic microstructure and reduced cage volume for rough particles. A combination of the mode-coupling theory, hydrodynamic modeling, and the activated hopping theory shows that these rough particles with significantly reduced localization lengths tend to become trapped in their glassy cages for extended periods of time. High-frequency data show that rough colloids, but not smooth colloids, display a transition from a free-draining to a fully lubricated state above the crossover volume fraction and, furthermore, exhibit solidlike behavior. Scaling analyses support the idea that lubrication forces between interlocking asperities are enhanced, leading to rotational constraints and stress-bearing structures that significantly elevate the viscoelasticity of dense suspensions. The results provide a framework for how particle surface topology affects the linear rheology in applications such as coatings, cement, consumer products, and shock-absorbing materials.

The rib cage: a new element in the spinopelvic chain.

This study analyzes anatomical variations of the thoracic cage (TC) according to spinopelvic alignment, age and gender using stereoradiography in erect position. This retrospective multicentric study analyzed computed parameters collected from free-standing position bi-planar radiographs, among healthy subjects. Collected data were: age, gender, pelvic parameters (Pelvic Incidence, Pelvic Tilt (PT) and Sacral Slope), T1-T12 Kyphosis (TK), L1-S1 Lordosis (LL), curvilinear spinal length, global TC parameters (maximum thickness and width,rib cage volume, mean Spinal Penetration Index (SPI)), 1st-10th rib parameters (absolute and relative (to the corresponding vertebra) sagittal angles). Totally, 256 subjects were included (140 females). Mean age was 34(range: 8-83). Significant correlations were found between TK and TC thickness (0.3,p < 0.001) and with TC Volume (0.3,p = 0.04), as well as rib absolute sagittal angle for upper and middle ribs (0.2,p = 0.02). Conversely, a -0.3 correlation has been exhibited between SPI and TK. Similar correlations were found with LL. PT significantly correlated with TC thickness (0.4,p = 0.003), SPI (-0.3,p = 0.03), and all rib relative sagittal angles. Among global TC parameters, only thickness and SPI significantly changed after 20years(respectively, 0.39 and -0.52,p < 0.001). Ribs relative sagittal angle showed negative correlation with age in skeletally mature subjects (p < 0.001). This study demonstrates the correlation between TC anatomy and spinopelvic parameters, confirming its part of the spinopelvic chain of balance. Indeed, higher spinal curvatures were associated with lower SPI and higher TC thickness, TC volume and rib absolute sagittal angles.

Fluoride-coated high-purity magnesium cage promotes bone fusion in goat models.

BackgroundCervical fusion devices made by polyether ether ketone (PEEK) cause concomitant effects which decompress the spinal cord and nerve roots. Magnesium has good biocompatibility and bioactivity as a biodegradable orthopedic implant material; however, its fusion rate is low. In this paper, we aimed to improve interbody fusion rate of high-purity magnesium (HP-Mg) by coating it with fluoride.MethodsFluoride-coated HP-Mg (F-HP-Mg) cages were prepared, and HP-Mg cages served as controls. We tested hydrogen release in phosphate-buffered saline (PBS) and weight loss in chromic acid. Anterior cervical discectomy and bone graft fusion (ACDF) was performed at the C2-C3 segment on goats with F-HP-Mg and HP-Mg cages to evaluate fusion score.ResultsHydrogen release of F-HP-Mg cages was significantly lower than that of HP-Mg cages. Weight was significantly decreased in both types of cages after rinsing with chromic acid, while F-HP-Mg cages were more resistant to corrosion compared to HP-Mg cages. There were no significant differences in disc space height (DSH) and remaining cage volume between the two groups in computed tomography (CT) images of goat cervical spine, while cavities were found at postoperative 12 weeks and confirmed by histological staining. No complications were found, while serum aspartate aminotransaminase (AST) level was significantly higher in the HP-Mg group compared to the F-HP-Mg group. Fusion rate at 24 weeks after ACDF was significantly higher with F-HP-Mg cages.ConclusionsThe use of F-HP-Mg improved histological fusion in the cervical intervertebral space of goats compared to HP-Mg and showed good biosafety.

Thermodynamic and kinetic corrosion behavior of alloys in molten MgCl2–NaCl eutectic: FPMD simulations and electrochemical technologies

Electrochemical corrosion of alloy materials is one of the biggest challenges in the development of heat transfer and storage technology by molten salt. Here, the thermodynamic and kinetic properties as well as microstructural characteristics of divalent alloying elements ( M = Ni, Co, Fe, Mn, Cr, and Ti) in molten MgCl 2 –NaCl (MN) eutectic are analyzed based on first principles molecular dynamics (FPMD) simulations and electrochemical experiments, aiming to reveal corrosion rules of alloy and explain corrosion phenomenon. First, special thermodynamic cycles are designed to calculate the redox potentials of M 2+ | M couples in molten MN, which are corrected by the experimental potential of Ni 2+ |Ni reference electrode. Then, ionic/atomic self-diffusion coefficients of molten salt mixtures are evaluated from FPMD simulations, whose credibility is verified by the results from cyclic voltammetry and chronopotentiometry. Studies have shown that the oxidation reaction of Ti are both thermodynamically and kinetically favorable, while the reactions of Fe and Cr are advantageous in thermodynamics and kinetics, respectively. Furthermore, the Ni enrichment on the alloy surface is explained by the larger diffusivity of Ni 2+ than Ni in molten MN, thereby the deposition order of Ni > Mn > Co is deduced. Last, the dynamic coordination numbers and cage volumes of cation-Cl clusters are captured, where the delayed shuttle of Cl − in molten FeCl 2 -MN verifies the strongest stability of [FeCl 6 ] 4− octahedral structure and the short activation time of Cl − in molten CrCl 2 -MN results in the fast corrosion rate of Cr. • Redox potentials of divalent metals in molten MN were studied by FPMD and experiments. • Oxidation reactions of Fe and Cr are separately thermodynamically and kinetically favorable. • Metal deposition or dissolution depends on the ratio of diffusion coefficients of M 2+ and M . • Shuttle intensity of Cl − in M -centered coordination cages determines the corrosion rate of M .