Circular Body Research Articles

A High Precision Fiber Bragg Grating Inclination Sensor for Slope Monitoring

A high precision and small size Fiber Bragg Grating (FBG) inclination sensor which is used for slope monitoring is proposed in this paper. The FBG inclination sensor has a pendulum structure for high precision and a circular body for easy installation in the common inclinometer pipe. The sensitivity of the FBG inclination sensor can reach 400 pm/deg by optimizing its parameters. The test results show the superior performance of this FBG inclination sensor in terms of static characteristics, and its sensitivity is 406.6 pm/deg. The comparison experiment shows the static characteristics of the FBG inclination sensor are better than the traditional electrical inclination sensor.

MHD Mixed Convection Flow in a Lid Driven Enclosure with a Sinusoidal Wavy Wall and a Heated Circular Body

MHD mixed convection flow in a lid driven enclosure with a sinusoidal wavy wall and heated circular body located at the center of the enclosure is studied numerically using finite element analysis. The upper wall is moving with a uniform velocity by unity, and other walls are in no slip condition. The enclosure vertical walls are insulated while the heated circular body inside the enclosure is maintained at a uniform temperature higher than the upper wall and lower wavy surface. Calculations are carried out through solving governing equations for different parameters by using finite element method. The investigation is conducted for various values of Richardson number <i>Ri</i> and Prandtl number <i>Pr</i>. The heat transfer characteristics and flow pattern inside the enclosure are presented in the form of streamlines and isothermal contours. Heat transfer rate in terms of the average Nusselt number and average fluid temperature inside the enclosure are presented for different parameters. The results indicate that the average Nusselt number at the heated surface and average temperature of the fluid inside the enclosure are strongly dependent on the configuration of the system under different geometrical and physical conditions.

Effects of Wavy Wall Amplitudes on Mixed Convection Heat Transfer in a Ventilated Wavy Cavity Filled by Copper-Water Nanofluid Containing a Central Circular Cold Body

Effects of Wavy Wall Amplitudes on Mixed Convection Heat Transfer in a Ventilated Wavy Cavity Filled by Copper-Water Nanofluid Containing a Central Circular Cold Body

Wave interactions with circular ice ridge embedded in level ice

The present study examines the wave interactions with a circular elastic body trapped within a thin cover of sea ice of substantial extent. This configuration is an idealization of an ice ridge embedded in a field of level ice. The ice cover and ice ridge are both modeled as thin elastic plates. Two independent approaches are used. The first approach ignores the finite draft, and a closed form solution is obtained by taking the inner product with respect to the eigenfunctions for the ice-covered region. The second approach includes the finite draft, and a least square approximation method is adopted along with the matching of velocity and pressure between the ice cover and ice ridge. Using the second approach, the surge force on the ice ridge, its deflection and the bending moments over the surface are then computed for various ridge configurations and wave characteristics. The submergence of the ridge is found to have a considerable effect on the deflection as well as the surge force in the presence of the ice cover. The results show that the level ice significantly affects the ice ridge response to shorter waves. It is found that the ridge embedded in ice cover experiences larger bending moments compared to the open water case. The results from the present study can help estimate the response of ice ridges to incoming waves, as well as aid in the design of offshore cylindrical structures embedded in level ice.

The effects of acrobatics on morphological characteristics of school children

The aim of this paper is to determine the effects of acrobatic elements on changes in morphological characteristics in children who were experimentally treated. The sample consists of elementary school children from Kosovska Mitrovica N = 52, who regularly attend physical education classes and additional acrobatics trainings three times a week for the implementation of acrobatics in additional classes of physical education. The variables used to assess the circular dimensions and body mass are: Upper arm circumference expressed in cm (AONDL), calf circumference expressed in cm (AOPTK), chest circumference expressed in cm AOGRK, body weight expressed in kg (AMAST). The variables used to estimate the subcutaneous fat tissue are: Upper-arm skinfold expressed in mm (ANNDL), calf skinfold expressed in mm (ANPTK), Abdominal skinfold expressed in mm ANTRB. A t-test was used to determine statistically significant differences in variables (ANNDL p=.006), (ANPTK p=.005), (ANTRB p=.008). The obtained results can contribute to the rationalization of regular and additional teaching of physical education for the optimal planning and control of work.

A 3D common-refinement method for non-matching meshes in partitioned variational fluid–structure analysis

We present a three-dimensional (3D) common-refinement method for non-matching unstructured meshes between non-overlapping subdomains of incompressible turbulent fluid flow and nonlinear hyperelastic structure. The fluid flow is discretized using a stabilized Petrov–Galerkin method, and the large deformation structural formulation relies on a continuous Galerkin finite element method. An arbitrary Lagrangian–Eulerian formulation with a nonlinear iterative force correction (NIFC) coupling is achieved in a staggered partitioned manner by means of fully decoupled implicit procedures for the fluid and solid discretizations. To begin, we first investigate the accuracy of common-refinement method (CRM) to satisfy the traction equilibrium condition along the fluid-elastic interface with non-matching meshes. We systematically assess the accuracy of CRM against the matching grid solution by varying grid mismatch between the fluid and solid meshes over a tubular elastic body. We demonstrate the second-order accuracy of CRM through uniform refinements of fluid and solid meshes along the interface. We then extend the error analysis to transient data transfer across non-matching meshes between the fluid and solid solvers. We show that the common-refinement discretization across non-matching fluid–structure grids yields accurate transfer of the physical quantities across the fluid–solid interface. We next solve a 3D fluid–structure interaction (FSI) problem of a cantilevered hyperelastic plate behind a circular bluff body and verify the accuracy of coupled solutions with respect to the available solution in the literature. By varying the solid interface resolution, we generate various non-matching grid ratios and quantify the accuracy of CRM for the nonlinear structure interacting with a laminar flow. We illustrate that the CRM with the partitioned NIFC treatment is stable for low solid-to-fluid density ratio and non-matching meshes for the 3D FSI problem. Finally, we demonstrate the 3D parallel implementation of the common-refinement with the NIFC method for a realistic engineering problem of drilling riser undergoing complex vortex-induced vibration with strong added mass effects and turbulent wake flow.

In vivo inhibition of circulating tumor cells by two apoptosis-promoting circular aptamers with enhanced specificity

Circulating tumor cells (CTCs) are known as the root cause of cancer metastasis that accounts for 90% of cancer death. Owing to the rarity of blood CTCs and their microenvironmental complexity, the existing biotechnology could not precisely capture and apoptosize CTCs in vivo for cancer metastasis prevention. Here, we designed two double strand circular aptamers aimed to simultaneously target MUC1 and HER2 surface biomarkers on mesenchymal cancer cells. The circular aptamers are composed of a capture arm for binding and seizing CTCs and a circular body for resisting degradation by exonucleases. We conjugated the two circular aptamers onto dendrimer PAMAM G4.5 (dcAp1-G-dcAp2), and the conjugate entity showed both significantly-enhanced biostability in serum for days compared with their linear counterparts and capture specificity in RBC (1:108) compared with their single circular aptamers. dcAp1-G-dcAp2 apoptosized the targeted cells and inhibited their bioenergetic activities significantly by lowing △Ψm, ATP and lactate productions while increasing ROS production. dcAp1-G-dcAp2 captured CTCs in mice in vivo and in patient blood. This study lays the foundation for developing multiple biostable circular aptamers and conjugating them together to precisely capture and apoptosize mesenchymal CTCs in vivo.

Microstructure of the eye tunics, eyelids and ocular glands of the Sulawesi bear cuscus (Ailurops ursinusTemminck, 1824) (Phalangeridae: Marsupialia) based on anatomical, histological and histochemical studies

AbstractThis study described the anatomy, histology and the histochemical analysis of the eye tunics, the upper and lower eyelid, the third eyelid, the lacrimal gland and the superficial gland of the third eyelid in adult Sulawesi bear cuscus. The eyeball and the eyelids with the orbital glands were harvested immediately post‐mortem. The eyeball in the Sulawesi bear cuscus had a sphere‐like shape. The pupil was round, and the lens was a circular biconvex body. There was neither tapetum lucidum nor Harderian gland. Similarly, there were no eyelashes in the lower eyelid. The lymphoid follicles and the high endothelial venules (HEV) were found in the lymphoid region only in the third eyelid and in the connective tissue of the superficial gland of the third eyelid. The third eyelid in the bear cuscus resembled the letter “T.” The lacrimal gland and superficial gland of the third eyelid were multilobar tubuloacinar glands. The histological analysis and histochemical studies showed that the lacrimal gland in the Sulawesi bear cuscus produced a mucoserous secretion with predominantly serous cells. In contrast, the superficial gland of the third eyelid produced a serous secretion with a single acinus mucous in character.

The Contrast of Axial Electrical Characteristics Between the Common Ring and the Cantor Fractal Circular Charged Body

The Contrast of Axial Electrical Characteristics Between the Common Ring and the Cantor Fractal Circular Charged Body

Average Depth versus Average Strike-Length of Fissure Veins for Specified Geometries: A Quantitative Approach

Fissure veins are very important source of mineral deposits particularly that of hydrothermal deposits. The average depth vs. average strike-length of fissure vein, which is an interesting topic, was discussed in Bateman (1962). Some say that depth is equal to length while others opined that depth may be equal to half the length. Here the question arises whether the ratio depth/length which is loosely used refers to depth to length at any given point of time or average depth vs. average length on a statistical basis. Infact these are empirical rules. The empirical rules hold good for an average basis only. Such problems are dealt under geometric probability. The ore body is more like a lens. Infact none of these hold good. The authors developed a method statistically for ore bodies of two geometries namely a circle and an ellipse. In the case of ellipse, three cases are considered namely, (i) the major axis of ellipse is horizontal to X – axis (ii) the major axis of ellipse is parallel to Y axis and (iii) the ellipse is inclined and whose major axis makes an angle θ with the X – axis. In any case, only circular ore body is considered in Bateman (1962). In the case of circular body it is shown that the ratio is neither equal to one or ½ as pointed in Bateman (1962).

A Stokes–Brinkman model of the fluid flow in a periodic cell with a porous body using the boundary element method

The problem of viscous incompressible flow in a periodic cell with a porous body is solved. The Stokes flow model is adopted to describe the flow outside the body and the Brinkman equation is applied to find the filtration velocity field inside the porous domain. The conditions on the boundary between the free fluid and the porous medium for the porous body of arbitrary shape are obtained. The boundary value problem for the joint solution of the biharmonic and Brinkman equations for the stream functions outside and inside the porous body are then solved using a boundary element method. Good agreement of the numerical and analytical models for the Kuwabara circular cell model is shown for the fluid flow through a porous circular cylinder. The fluid flow past a circular, square, triangular cylinders and a circular body of uneven surface (an idealized model of a viral capsid) in a rectangular periodic cell are calculated. Comparison of the results obtained with the numerical solution from a CFD ANSYS/FLUENT model shows good accuracy of the developed mathematical model.

The Global Stability of 2-D Subsonic Circulatory Flows for the Steady Isothermal Gas

This paper is a complement of our work in (Cui &amp; Li, 2011) where we have established the global subsonic circulatory solution for the polytropic gas. In this paper, we are concerned with the global stability of the 2-D subsonic circulatory flow around a perturbed circular body for the isothermal gas. The flow is assumed to be isothermal, isentropic, irrotational and described by a steady Euler equations, which can be reduced into a second order quasilinear elliptic equation in a exterior domain with suitable physical conditions. The unique existence and the state of the flow at infinity are obtained under nature physical assumption.

Hydrodynamic characteristics of internal waves induced by a heaving body in a two-layer fluid

The stratification of fluid caused by the change of water densities can generate two water waves on each fluid boundary. One is the surface wave on the free surface, and the other is the internal wave on the interface between the fluid layers. Two wave modes exist in the two-layer fluid: barotropic mode and baroclinic mode. This study develops a numerical model to simulate the surface and internal waves in the time domain. The time histories of the water waves on both surface boundaries are simulated using the numerical wave tank (NWT) technique by an oscillating circular body located on the free surface or underwater in the lower fluid domain. The NWT technique is based on the boundary element method with properly defined boundary conditions, including interface boundaries. The leapfrog method is used for the time integration of the water surface boundary conditions. The time-varying generated waves are disassembled through the Fast Fourier Transform (FFT). Each wave component is compared with analytic solutions. The relative magnitudes of the generated waves on both fluid layers are examined according to each wave mode. The dominant wave mode varies according to the oscillating body frequencies. The amplitude ratios of the two waves are compared for various density ratios and fluid depths.

Heat transfer and particle migration in nanofluid flow around a circular bluff body using a two-way coupled Eulerian-Lagrangian approach

Nanofluids are engineered suspensions of fine nanoparticles in basefluids. Being a two-component system, different numerical approaches are available to model the thermo-fluidic behavior of nanofluids. In this study, a two-way coupled Eulerian-Lagrangian approach based Discrete Phase Modeling (DPM) has been used to numerically study the flow and heat transfer of nanofluids around a circular bluff body. A 2-D, laminar, steady and forced convective flow of Al2O3-H2O nanofluid around a hot circular cylinder at a constant temperature has been considered. Governing equations of motion and energy transfer for the continuous phase (basefluid) were solved using a finite volume approach and the nanoparticles (discrete phase) were individually tracked in a Lagrangian reference frame by solving the particle force balance equation. Results are presented at 10⩽Re⩽40 and particle volume fraction (ϕ) varying from 0% to 5%. Heat transfer performance of nanofluids is presented in terms of local and average Nusselt numbers. As expected, Nusselt numbers increased with increase in particle volume fraction and Reynolds number. Results indicated that the heat transfer characteristics are notably influenced by Brownian motion and thermophoresis. Effects of reflect and trap boundary conditions for the particulate phase at the cylinder wall, on heat transfer characteristics of nanofluids are also discussed. Special attention has been paid to the distribution of nanoparticles in the flow domain. It is noted that, nanoparticle distribution is non-homogeneous in the proximity of cylinder and in the recirculation region. This observation is in complete contradiction with the basic assumption of conventional Single Phase Modeling (SPM) approach. Results of DPM analysis significantly vary from that of the SPM approach. Furthermore, it is observed that nanofluids with smaller nanoparticles are capable of producing higher heat transfer rates.

Numerical study of natural and mixed convection in a square cavity filled by a Cu–water nanofluid with circular heating and cooling cylinders

The present study investigates the role of natural and mixed convection heat transfer of a Cu–water nanofluid in a square cavity with inside circular heating and cooling bodies. The finite volume discretization method with the Semi-Implicit Method for Pressure Linked Equations algorithm is employed for solving the two-dimensional Navier–Stokes and energy equations. The effects of various design parameters on the heat transfer rate are investigated. Design parameters used in this numerical simulation are the position and size of circular bodies. A wide range of parameters such as the Rayleigh number (103 ≤ Ra ≤ 106 ), volume fraction (0 ≤ ϕ ≤ 0.05), Richardson number (0.01 ≤ Ri ≤ 1000), and the Grashof number (102 ≤ Gr ≤ 104 ) has been used. The numerical analysis is carried out for the circular body’s positions on the vertical centerline of the cavity. The circular body’s positions on the vertical left-line of the cavity are also presented and discussed for comparison purposes. The results show that the optimal heat transfer is obtained when placing the circular body near the bottom wall. Furthermore, the effects of pair of circular bodies on the heat transfer rate are investigated. The simulations show that the heat transfer rate increases with changing the orientation of the pair of circular bodies from the horizontal to the vertical directions. For the case of the mixed convection process, it is found that at high Richardson numbers, the effect of moving walls decreases and the heat transfer rate changes significantly.

An extended iterative direct-forcing immersed boundary method in thermo-fluid problems with Dirichlet or Neumann boundary conditions

An iterative direct-forcing immersed boundary method is extended and used to solve convection heat transfer problems. The pressure, momentum source, and heat source at immersed boundary points are calculated simultaneously to achieve the best coupling. Solutions of convection heat transfer problems with both Dirichlet and Neumann boundary conditions are presented. Two approaches for the implementation of Neumann boundary condition, i.e. direct and indirect methods, are introduced and compared in terms of accuracy and computational efficiency. Validation test cases include forced convection on a heated cylinder in an unbounded flow field and mixed convection around a circular body in a lid-driven cavity. Furthermore, the proposed method is applied to study the mixed convection around a heated rotating cylinder in a square enclosure with both iso-heat flux and iso-thermal boundary conditions. Computational results show that the order of accuracy of the indirect method is less than the direct method. However, the indirect method takes less computational time both in terms of the implementation of the boundary condition and the post processing time required to compute the heat transfer variables such as the Nusselt number. It is concluded that the iterative direct-forcing immersed boundary method is a powerful technique for the solution of convection heat transfer problems with stationary/moving boundaries and various boundary conditions.

Morphological status of eight-year-old girls of varying degrees of nutritional status

Nutritional status of children is one of the most important indicators of health, mental and physical capabilities and potential for normal and healthy growth and development. The aim of this study was to determine differences in morphological characteristics in eight-year-old girls with varying degrees of nutritional status. The research was conducted on a sample of 91 second grade students of elementary schools in Niš, aged 8.06 (± 0.02). Based on the BMI, three sub-samples were formed (normal weight, overweight and obese subjects). Morphological status was determined by measuring the parameters of longitudinal, transversal and circular dimensionality, body weight and subcutaneous fatty tissue. Differences in morphological variables were determined by using MANOVA/ANOVA and LSD Post Hoc test. The results indicate that, in regards to the BMI, there are significant differences in morphological characteristics in eight-year-old girls. The highest values were observed in obese, then overweight, while the value for at least had a normal weight girls.

Forced convective heat transfer of nanofluids around a circular bluff body with the effects of slip velocity using a multi-phase mixture model

Forced convective heat transfer around a circular cylinder using nanofluids has been numerically analyzed employing a mixture model based Multi-Phase Modeling (MPM) approach. A hot circular cylinder with a constant wall temperature is exposed to a free stream of Al2O3–H2O nanofluid at ambient temperature. The flow is steady, laminar and two dimensional in the Reynolds number range of 10⩽Re⩽40. The governing equations of flow and energy transfer along with the respective boundary conditions are numerically solved using a Finite Volume Method (FVM) based on SIMPLE algorithm. The prime aim of this work is to highlight the effects of slip velocity, volume concentration and diameter of nanoparticles on heat transfer characteristics of nanofluids. Results indicate that heat transfer increases with increase in nanoparticle volume fraction. The highest mean Nusselt number is observed at ϕ=5% at any Reynolds number. It is also noted that, nanofluids with smaller nanoparticles result in higher heat transfer rates. Particular attention has been paid to the variation of heat transfer characteristics when the modeling approach is switched from Single-Phase Modeling (SPM) to mixture model based MPM. It is revealed that higher heat transfer rates are observed in MPM which considers the effects of slip velocity.

Analysis of Diagnosis Related Groups and their Impact on Health Care in Post Massive Weight Loss Surgery

Diagnosis Related Groups (DRG) were introduced in Germany as a medico-economic classification system in 2004. In this analysis, we looked at restorative surgery after massive weight loss, focusing on reimbursement of this fee-per-case system in comparison to costs to deduce possible effects on health care over time. First we analysed the algorithms for the relevant DRGs including data about length of stay and reimbursement. Furthermore, we integrated cost data from German reference hospitals of the last 5 years as well as single-centre data from a university hospital. Due to a diagnosis-related algorithm, coding will constantly lead to DRG K07Z. In 2016, a new diagnosis code specific to massive weight loss was introduced, which now leads to DRG J10B. As a result, reimbursement is reduced by more than half. In the cost matrix, staff, general ward, operation theatre and anaesthesia were identified as the main cost drivers. As expected, there was a statistically significant correlation between general ward costs and time of stay in hospital as well as operation theatre costs and incision-suture time. Considering the cost data of the reference hospitals, there was an average excess of EUR 781 per case whereas our own cost data revealed a deficit of EUR 1 700 to 2 700 per case. This is mainly due to the fact that approximately one third of our patient cohort underwent highly elaborate circular body lifts. It has to be questioned whether a newly introduced main diagnosis code can be applied as such without any underlying cost data having been collected in previous years. Given unchanged treatment measures, the main cost drivers identified by us remain the same, which means that there is no rationale for a drop in revenue. In addition to providing incentives for an efficient use of resources and quality optimisation, this system should offer medical service providers a sustainable and realistic possibility to break even.

Imagens que carregamos às costas

O artigo parte de uma análise da obra de Daniel Barroca Circular Body para abordar o congresso Liberation Struggles, The ‘Falling of the Empire’ and the Birth (through Images) of African Nations, que aconteceu em Reading e Londres o 27 e o 28 de janeiro. O texto foca-se no questionamento das imagens e no trabalho com o arquivo que foi apresentado nas distintas comunicações.